Gold Fish 3/goldfish_volume_3.bin/files/fish/disks/d1015.lha/Programs/SnoopDos/Source.lha/Source/patches.c

C/C++ Source or Header | 1994-09-18 | 136.1 KB | 4,804 lines

/*
 *        PATCHES.C                                    vi:ts=4
 *
 *      Copyright (c) Eddy Carroll, September 1994.
 *
 *        Controls the patching of dos.library and other functions in a
 *        reliable manner.
 */

#define DEBUG_PATTERN        0

#define MONITOR_SEMAPHORE    0
#define STACK_CHECK            0        /* Not currently used */

#pragma libcall SysBase RawPutChar 204 001

#include "system.h"
#include "snoopdos.h"
#include "patches.h"

/*
 *        These four pointers are imported from PATCHCODE.S, which is
 *        also where the real code size is determined.
 */
#define CODESIZE        88    /* Must equal PatchCode_End - PatchCode_Start   */
#define STACKADJUST        14    /* Must equal pc_JumpOrigFunc - pc_NormalReturn */

#define PatchCode_Size          (PatchCode_End - PatchCode_Start)
#define PatchCode_StackAdjust (PatchCode_JumpOrigFunc - PatchCode_NormalReturn)

extern char far PatchCode_Start[];
extern char far PatchCode_NormalReturn[];
extern char far PatchCode_JumpOrigFunc[];
extern char far PatchCode_End[];

#define ASM    __asm __saveds

#if MONITOR_SEMAPHORE
Task *LoadTask;                /* Indicates we're inside LoadSeg() */
#endif

/*
 *        Now some packet IDs not defined by Commodore in dos/dosextens.h
 */
#define ACTION_DOUBLE          2000    /* Conman: create pipe filehandle    */
#define ACTION_FORCE          2001    /* Conman: Force input into handler    */
#define ACTION_DROP              2004    /* Conman: Discard all queued input    */

#define ACTION_GET_DISK_FSSM  4201    /* Get disk startup message            */
#define ACTION_FREE_DISK_FSSM 4202    /* Free disk startup message        */

/*
 *        Next, our three message types for the background process. These
 *        correspond to pattern and pathname expansion messages.
 */
#define QUIT_MSG        0
#define PATTERN_MSG        1
#define PATHEXPAND_MSG    2

/*
 *        Some miscellaneous strings
 */
char LinkPointerString[] = " --> ";

/*
 *        I needed a quick way to hook into ReleaseSemaphore() to try and
 *        figure out why ramlib would sometimes crash on calling it. What
 *        better way to do this than by re-using one of our existing
 *        patched functions (one which takes a parameter in A0). OpenDevice
 *        fits the bill nicely (we just ignore the additional parameters).
 */
#if MONITOR_SEMAPHORE
#undef LVO_OpenDevice
#define LVO_OpenDevice        -570 // ReleaseSemaphore() LVO vector
#endif

/*
 *        This structure is used to communicate between the PutMsg() patch
 *        and the background SnoopDos process when doing path expansion
 *        for ACTION_MAKE_LINK or ShowFullPaths (when we're monitoring packets,
 *        we can't guarantee that the calling processes' message port is free).
 */
typedef struct NameFromLockMsg {
    struct Message  msg;        /* Standard exec message                */
    int                type;        /* Type of this message                    */
    BPTR            lock;        /* Lock to calculate path relative to    */
    char            *filename;    /* Filename relative to lock            */
    char            *buf;        /* Buffer to store result in            */
    int                maxlen;        /* Maximum length of buffer                */
    char            *newbuf;    /* On return, points to path in buffer     */
    int                sigmask;    /* Signal number to signal when done    */
    Task            *task;        /* Task to signal when done                */
} NameFromLockMsg;

/*
 *        This structure is used to communicate between the patches and
 *        the background SnoopDos process when doing pattern matching.
 */
typedef struct PatternMsg {
    struct Message    msg;        /* Standard exec message                */
    int                type;        /* Type of this message                    */
    char            *name;        /* Name of task to check                */
    int                match;        /* Result of pattern match (1 == okay)    */
    int                sigmask;    /* Signal number to signal when done    */
    Task            *task;        /* Task to signal when done                */
} PatternMsg;

/*
 *        This structure is used to cache the results of pattern comparisons
 *        for various tasks.
 */
typedef struct PatternCache {
    struct MinNode    node;        /* Used to link items together                */
    Task            *task;        /* ID of task stored in this entry            */
    char            name[PC_NAMELEN];/* Name of task stored in this entry    */
    int                match;        /* True=monitor this task, false=don't        */
} PatternCache;

PatternCache    PCacheEntries[NUM_PCACHE_ENTRIES];    /* Entries on list        */
MsgPort            BackgroundPort;    /* Where to send pattern match requests to    */
List            PatternList;    /* List of cached patterns                    */
Semaphore        PatternCacheSem;/* Sem to control access to pattern cache      */
Semaphore        PatternBufSem;    /* Sem to control access to pattern buffer    */
Semaphore        TaskCacheSem;    /* Sem used to arbitrate cache access        */
Semaphore        DosDeviceSem;    /* Sem used to control access to dev list    */
Process            *BackgroundProc;/* Process used to do pattern matching        */
ULONG            PatternEnabled;        /* If true, pattern matching is enabled    */
ULONG            PatternWildcard;    /* If true, pattern contains a wildcard    */
Task            *SnoopTask;            /* Pointer to our own task                */
Task            *RamLibTask;        /* Pointer to RamLib process            */
Task            *RealRamLibTask;    /* Pointer to Ramlib process (always!)    */
Task            *InputTask;            /* Pointer to input.device's task        */
ULONG            NewEventSig    = -1;/* Signal bit used when new event ready    */
ULONG            ScanDosListSig = -1;/* Signal bit used to say rescan list    */
ULONG            TaskCacheIndex = 1; /* Index into task cache array            */

#define PAT_MAX_LEN    (MAX_STR_LEN   + 50)
#define PAT_BUF_LEN    (PAT_MAX_LEN*2 + 3)

char            PatternString[PAT_MAX_LEN];            /* Holds source pattern    */
char            PatternBuf[PAT_BUF_LEN];            /* Holds parsed pattern    */
Task            *CachedTask[NUM_CACHED_TASKS];        /* Holds cached tasks    */
Task            *DeviceTaskList[MAX_DOS_DEVICES];    /* Holds device IDs        */

/*
 *        This structure records outstanding packets (for direct packet i/o
 *        that bypasses AmigaDOS) which we are watching out for a reply to.
 *        We keep all the additional info because it's likely that any given
 *        task will re-use a packet structure when sending packets to different
 *        DOS processes, and we want to be able to distinguish these cases.
 */
typedef struct WaitPacket {
    struct    MinNode        node;            /* Used to link items together    */
    struct    DosPacket    *dp;            /* Packet that was dispatched    */
    struct    Task        *sendtask;        /* Task that sent it            */
    struct    MsgPort        *destport;        /* Port it was sent to            */
    LONG    eventnum;                    /* Associated event number        */
    Event    *event;                        /* Associated event pointer        */
    ULONG    arg1;                        /* ARG1 of the packet            */
    ULONG    arg2;                        /* ARG2 of the packet            */
    ULONG    arg3;                        /* ARG3 of the packet            */
    char    *resmsg;                    /* Message to use for result    */
    UWORD    flags;                        /* Flags associated with result    */
} WaitPacket;

Semaphore    PacketSem;                            /* Arbitrates list access    */
struct List PacketWaitList;                        /* List of waiting packets    */
struct List    PacketFreeList;                        /* List of free nodes        */
WaitPacket    PacketEntries[NUM_PACKET_ENTRIES];    /* The nodes on the list    */

/*
 *        Prototypes for all our replacement patched functions
 */

void BackgroundProcCode(void);
char *MyNameFromLock(BPTR lock, char *filename, char *buf, int maxlen);

typedef unsigned long (*FuncPtr)();

#define FPROTO(name)    ULONG ASM New_##name(){return (0);}
#define DPROTO(name)    ULONG ASM New_##name();

DPROTO(AddDosEntry)
DPROTO(CurrentDir)
DPROTO(DeleteFile)
DPROTO(Execute)
DPROTO(GetVar)
DPROTO(FindVar)
DPROTO(LoadSeg)
DPROTO(NewLoadSeg)
DPROTO(Lock)
DPROTO(CreateDir)
DPROTO(MakeLink)
DPROTO(Open)
DPROTO(Rename)
DPROTO(RunCommand)
DPROTO(SetVar)
DPROTO(DeleteVar)
DPROTO(SystemTagList)

DPROTO(FindPort)
DPROTO(FindResident)
DPROTO(FindSemaphore)
DPROTO(FindTask)
DPROTO(OpenDevice)
DPROTO(OpenLibrary)
DPROTO(OpenResource)
DPROTO(PutMsg)

DPROTO(OpenFont)
DPROTO(LockPubScreen)
DPROTO(FindToolType)
DPROTO(MatchToolValue)

/*
 *        These two defines control whether or not a patch is enabled. It's
 *        vital that PATCH_ENABLED be -1 rather than simply any non-zero
 *        value -- see the comments in patchcode.s for more details.
 */
#define PATCH_ENABLED        ((ULONG)(-1))
#define PATCH_DISABLED        0

/*
 *        MarkCallAddr
 *        CallAddr
 *
 *        These two macros allow us to determine what address we were called
 *        from in a patch function. MarkCallAddr should be the first
 *        declaration at the start of the patch function, and then CallAddr
 *        will correspond to the caller's address throughout that function.
 *        callmarker[0] is the place marker itself, callmarker[1] is the
 *        immediate return address, and callmarker[3] takes into the
 *        account the assembly language patch stub as well.
 */
#define MarkCallAddr        ULONG volatile callmarker[1]
#define CallAddr            (callmarker[6])

/*
 *        JumpOrigFunc(retval)
 *
 *        This macro lets us return and call the original function from the
 *        resident patch code rather than from our C code. The passed
 *        parameter can be 0 in most cases, but if the function we're using
 *        this in had a formal parameter passed in reg_d0, then that
 *        formal parameter must be used as the return value.
 *
 *        We implement this by patching the stack directly to adjust the
 *        return address so that we arrive back at a second bit of code
 *        instead of the first bit.
 */
#define JumpOrigFunc(retval) \
    { callmarker[1] += STACKADJUST; \
      return (ULONG)(retval); }

/*
 *        The patch structure itself. Don't change the order of the first
 *        four fields without updating the code in PATCHCODE.S as well!
 *
 *        Note that we use a library number rather than a pointer to an
 *        actual library, for convenience.
 */
typedef struct Patch {
    UWORD    code[CODESIZE/2];        /* Assembly code to handle patch    */
    FuncPtr    origfunc;                /* Original function pointer        */
    FuncPtr    newfunc;                /* Replacement function pointer        */
    ULONG    enabled;                /* If -1, patch currently active    */
    void    *sysbase;                /* Points to ExecBase                */
    ULONG    stackneeded;            /* #bytes free stack required        */
    UWORD    usecount;                /* No. of tasks currently in code    */
    UWORD    library;                /* Library to patch                    */
    WORD    offset;                    /* Offset into library                */
    WORD    pad;                    /* Keep structure longword-aligned    */
} Patch;

#define PATCH_DEF(lib,func)    { lib, LVO_##func, (FuncPtr)New_##func }
#define PATCH_END            { 0, 0, 0 }

/*
 *        This structure is used to initialise the main Patch array in memory.
 *
 *        IMPORTANT -- these patches MUST be defined in exactly the same
 *        order as the first entries in the GID_* defines in snoopdos.h
 *        since those same GID_* values are used to toggle the patches
 *        on and off.
 */
struct PatchInitTable {
    UWORD    library;                /* Library number to patch            */
    WORD    offset;                    /* Offset in that library            */
    FuncPtr    newfunc;                /* Replacement function to call        */
} PatchInit[] = {
    PATCH_END,
    PATCH_DEF(    EXEC_LIB,        FindPort        ),    /* GID_FINDPORT            */
    PATCH_DEF(    EXEC_LIB,        FindResident    ),    /* GID_FINDRESIDENT        */
    PATCH_DEF(    EXEC_LIB,        FindSemaphore    ),    /* GID_FINDSEMAPHORE    */
    PATCH_DEF(    EXEC_LIB,        FindTask        ),    /* GID_FINDTASK            */
    PATCH_DEF(    INTUITION_LIB,    LockPubScreen    ),    /* GID_LOCKSCREEN        */
    PATCH_DEF(    EXEC_LIB,        OpenDevice        ),    /* GID_OPENDEVICE        */
    PATCH_DEF(    GRAPHICS_LIB,    OpenFont        ),    /* GID_OPENFONT            */
    PATCH_DEF(    EXEC_LIB,        OpenLibrary        ),    /* GID_OPENLIBRARY        */
    PATCH_DEF(    EXEC_LIB,        OpenResource    ),    /* GID_OPENRESOURCE        */
    PATCH_DEF(    ICON_LIB,        FindToolType    ),    /* GID_READTOOLTYPES    */
    PATCH_DEF(  EXEC_LIB,        PutMsg          ),    /* GID_SENDREXX            */

    PATCH_DEF(    DOS_LIB,        CurrentDir        ),    /* GID_CHANGEDIR        */
    PATCH_DEF(    DOS_LIB,        DeleteFile        ),    /* GID_DELETE            */
    PATCH_DEF(    DOS_LIB,        Execute            ),    /* GID_EXECUTE            */
    PATCH_DEF(    DOS_LIB,        GetVar            ),    /* GID_GETVAR            */
    PATCH_DEF(    DOS_LIB,        LoadSeg            ),    /* GID_LOADSEG            */
    PATCH_DEF(    DOS_LIB,        Lock            ),    /* GID_LOCKFILE            */
    PATCH_DEF(    DOS_LIB,        CreateDir        ),    /* GID_MAKEDIR            */
    PATCH_DEF(    DOS_LIB,        MakeLink        ),    /* GID_MAKELINK            */
    PATCH_DEF(    DOS_LIB,        Open            ),    /* GID_OPENFILE            */
    PATCH_DEF(    DOS_LIB,        Rename            ),    /* GID_RENAME            */
    PATCH_DEF(    DOS_LIB,        RunCommand        ),    /* GID_RUNCOMMAND        */
    PATCH_DEF(    DOS_LIB,        SetVar            ),    /* GID_SETVAR            */
    PATCH_DEF(    DOS_LIB,        SystemTagList    ),    /* GID_SYSTEM            */

    /*
     *        Now the paired functions that track their partner's state
     */
    PATCH_DEF(    ICON_LIB,        MatchToolValue    ),    /* GID_READTOOLTYPES2    */
    PATCH_DEF(    DOS_LIB,        NewLoadSeg        ),    /* GID_LOADSEG2            */
    PATCH_DEF(    DOS_LIB,        FindVar           ),    /* GID_GETVAR2             */
    PATCH_DEF(    DOS_LIB,        DeleteVar         ),    /* GID_SETVAR2          */
    PATCH_DEF(  DOS_LIB,        AddDosEntry        ),    /* GID_ADDDOSENTRY        */

    PATCH_END
};

#define PatchInitCount    (sizeof(PatchInit) / sizeof(PatchInit[0]))
#define PatchInitSize    (PatchInitCount * sizeof(Patch))

/*
 *        This anchor structure is used to let us locate the patches if we
 *        quit SnoopDos and then rerun it -- the patches themselves always
 *        stay in memory once loaded.
 */
typedef struct {
    Semaphore    sem;            /* Semaphore to arbitrate access to patches    */
    char        name[30];        /* Somewhere permanent to store sem name    */
    Patch        patchdata[1];    /* This is an open-ended array                */
} PatchAnchorData;

PatchAnchorData *PatchAnchor;    /* Points to the current patch anchor        */

/*
 *        If SAS/C allowed us to examine the value of Enum types from
 *        within the preprocessor, the following check would actually work
 */
#if SASC_ALLOWS_ENUM_CHECKS
#if (sizeof(PatchInit)/sizeof(PatchInit[0])) < (GID_NUMPATCHES+1)
#error "PatchInit[] table has too few entries for patches"
#else
#if (sizeof(PatchInit)/sizeof(PatchInit[0])) > (GID_NUMPATCHES+1)
#error "PatchInit[] table has too many entries for patches"
#endif
#endif
#endif

void *LibList[NUM_LIBS];

Patch *PatchList;

/*
 *        Now we have a big table of DOS packets that we recognise while
 *        monitoring. For each packet, we record the internal AmigaDOS ID
 *        we use to recognise it, the message ID of its name, the number
 *        of dp_Args to display, and the number of results to display.
 */

/*        The following constants define how many parameters are returned
 *        by the handler when it receives this packet. PK_0 means there is
 *        no return value, PK_1 means 1 return value, PK_2 means there are
 *        two return values (with the second being the error code if the
 *        first one indicates failure) and PK_2OK means there are two actual
 *        returned values, both of which are legitimate.
 */
#define PK_0            0            /* No return value from this packet        */
#define PK_1            1            /* One return value from this packet    */
#define PK_2            2            /* Two return values from this packet    */
#define PK_2OK            3            /* Two return values even when okay        */
#define PK_MASK            3            /* Used to extract PK_CODE                */

/*
 *        How to detect when an event failed. Selecting none of these means
 *        that the packet can never fail.
 */
#define PKF_BOOL        0x08        /* True if zero result == fail            */
#define PKF_NEG            0x10        /* True if -1 result == fail            */

/*
 *        We want to completely ignore some packets, namely all those sent
 *        by the handler to lower level devices like timer.device or scsi.device
 *        for its own needs. We use PK_IGNORE to identify all such packets
 *        so we can discard them.
 *
 *        PK_COMMON packets are those which are monitored when the
 *        "Monitor Packets" option is enabled. These are connected
 *        with the associated DOS functions Open(), Lock() etc. and
 *        are output as such by SnoopDos, rather than as raw packets.
 *
 *        PK_RAW is used for our sentinel packet which indicates that
 *        even the packet type should be output since it's not recognised.
 */
#define PK_COMMON        0x20        /* Common packet (Open, Lock, etc.)        */
#define PK_RAW            0x40        /* Completely raw packet                */
#define PK_IGNORE        0x80        /* Ignore this packet completely        */

/*
 *        Most packets return a value in dp_Res1 and if that value is
 *        zero or -1, then the error code is in dp_Res2. We define
 *        two constants to handle these common case.
 */
#define PK_BOOLEAN        (PKF_BOOL | PK_2)
#define PK_NEGATIVE        (PKF_NEG  | PK_2)

/*
 *        Warning: this table MUST be sorted by packet ID in ascending order,
 *        since a binary search is used to locate packet types
 */
#define LAST_PACK_MSG        0

struct PacketRef {
    UWORD    packetid;                /* The ID we watch out for                */
    UWORD    msgid;                    /* The name of the action to print        */
    UBYTE    numparams;                /* Number of parameters to display        */
    UBYTE    flags;                    /* How to interpret the result            */
} PacketTable[] = {
    ACTION_STARTUP,            MSG_ACT_STARTUP,         1, PK_1,
    ACTION_GET_BLOCK,        MSG_ACT_GET_BLOCK,         1, PK_IGNORE,
    ACTION_SET_MAP,            MSG_ACT_SET_MAP,         1, PK_IGNORE,
    ACTION_DIE,                MSG_ACT_DIE,             0, PK_BOOLEAN,
    ACTION_EVENT,            MSG_ACT_EVENT,             1, PK_IGNORE,
    ACTION_CURRENT_VOLUME,    MSG_ACT_CURRENT_VOLUME,     1, PK_2OK,
    ACTION_LOCATE_OBJECT,    MSG_ACT_LOCATE_OBJECT,     3, PK_BOOLEAN | PK_COMMON,
    ACTION_RENAME_DISK,        MSG_ACT_RENAME_DISK,     1, PK_BOOLEAN,
    ACTION_FREE_LOCK,        MSG_ACT_FREE_LOCK,         1, PK_BOOLEAN,
    ACTION_DELETE_OBJECT,    MSG_ACT_DELETE_OBJECT,     2, PK_BOOLEAN | PK_COMMON,
    ACTION_RENAME_OBJECT,    MSG_ACT_RENAME_OBJECT,     4, PK_BOOLEAN | PK_COMMON,
    ACTION_MORE_CACHE,        MSG_ACT_MORE_CACHE,         1, PKF_BOOL   | PK_2OK,
    ACTION_COPY_DIR,        MSG_ACT_COPY_DIR,         1, PK_BOOLEAN,
    ACTION_WAIT_CHAR,        MSG_ACT_WAIT_CHAR,         1, PKF_BOOL   | PK_2OK,
    ACTION_SET_PROTECT,        MSG_ACT_SET_PROTECT,     4, PK_BOOLEAN,
    ACTION_CREATE_DIR,        MSG_ACT_CREATE_DIR,         2, PK_BOOLEAN | PK_COMMON,
    ACTION_EXAMINE_OBJECT,    MSG_ACT_EXAMINE_OBJECT,     2, PK_BOOLEAN,
    ACTION_EXAMINE_NEXT,    MSG_ACT_EXAMINE_NEXT,     2, PK_BOOLEAN,
    ACTION_DISK_INFO,        MSG_ACT_DISK_INFO,         1, PK_BOOLEAN,
    ACTION_INFO,            MSG_ACT_INFO,             2, PK_BOOLEAN,
    ACTION_FLUSH,            MSG_ACT_FLUSH,             0, PK_BOOLEAN,
    ACTION_SET_COMMENT,        MSG_ACT_SET_COMMENT,     4, PK_BOOLEAN,
    ACTION_PARENT,            MSG_ACT_PARENT,             1, PK_BOOLEAN,
    ACTION_TIMER,            MSG_ACT_TIMER,             1, PK_IGNORE,
    ACTION_INHIBIT,            MSG_ACT_INHIBIT,         1, PK_BOOLEAN,
    ACTION_DISK_TYPE,        MSG_ACT_DISK_TYPE,         1, PK_IGNORE,
    ACTION_DISK_CHANGE,        MSG_ACT_DISK_CHANGE,     1, PK_1,
    ACTION_SET_DATE,        MSG_ACT_SET_DATE,         4, PK_BOOLEAN,
    ACTION_SAME_LOCK,        MSG_ACT_SAME_LOCK,         2, PK_BOOLEAN,
    ACTION_READ,            MSG_ACT_READ,             3, PK_NEGATIVE,
    ACTION_WRITE,            MSG_ACT_WRITE,             3, PK_NEGATIVE,
    ACTION_SCREEN_MODE,        MSG_ACT_SCREEN_MODE,     1, PK_BOOLEAN,
    ACTION_CHANGE_SIGNAL,    MSG_ACT_CHANGE_SIGNAL,     3, PKF_BOOL   | PK_2OK,
    ACTION_READ_RETURN,        MSG_ACT_READ_RETURN,     1, PK_IGNORE,
    ACTION_WRITE_RETURN,    MSG_ACT_WRITE_RETURN,     1, PK_IGNORE,
    ACTION_FINDUPDATE,        MSG_ACT_FINDUPDATE,         3, PK_BOOLEAN | PK_COMMON,
    ACTION_FINDINPUT,        MSG_ACT_FINDINPUT,         3, PK_BOOLEAN | PK_COMMON,
    ACTION_FINDOUTPUT,        MSG_ACT_FINDOUTPUT,         3, PK_BOOLEAN | PK_COMMON,
    ACTION_END,                MSG_ACT_END,             1, PK_BOOLEAN,
    ACTION_SEEK,            MSG_ACT_SEEK,             3, PK_NEGATIVE,
    ACTION_FORMAT,            MSG_ACT_FORMAT,             2, PK_BOOLEAN,
    ACTION_MAKE_LINK,        MSG_ACT_MAKE_LINK,         4, PK_BOOLEAN | PK_COMMON,
    ACTION_SET_FILE_SIZE,    MSG_ACT_SET_FILE_SIZE,     3, PK_NEGATIVE,
    ACTION_WRITE_PROTECT,    MSG_ACT_WRITE_PROTECT,     2, PK_BOOLEAN,
    ACTION_READ_LINK,        MSG_ACT_READ_LINK,         4, PK_BOOLEAN,
    ACTION_FH_FROM_LOCK,    MSG_ACT_FH_FROM_LOCK,     2, PK_BOOLEAN,
    ACTION_IS_FILESYSTEM,    MSG_ACT_IS_FILESYSTEM,     0, PK_BOOLEAN,
    ACTION_CHANGE_MODE,        MSG_ACT_CHANGE_MODE,     3, PK_BOOLEAN,
    ACTION_COPY_DIR_FH,        MSG_ACT_COPY_DIR_FH,     1, PK_BOOLEAN,
    ACTION_PARENT_FH,        MSG_ACT_PARENT_FH,         1, PK_BOOLEAN,
    ACTION_EXAMINE_ALL,        MSG_ACT_EXAMINE_ALL,     5, PK_BOOLEAN,
    ACTION_EXAMINE_FH,        MSG_ACT_EXAMINE_FH,         2, PK_BOOLEAN,
    ACTION_EXAMINE_ALL_END,    MSG_ACT_EXAMINE_ALL_END, 5, PK_BOOLEAN,
    ACTION_SET_OWNER,        MSG_ACT_SET_OWNER,         4, PK_BOOLEAN,
    ACTION_DOUBLE,            MSG_ACT_DOUBLE,             3, PK_BOOLEAN,
    ACTION_FORCE,            MSG_ACT_FORCE,             3, PK_BOOLEAN,
    ACTION_STACK,            MSG_ACT_STACK,             3, PK_BOOLEAN,
    ACTION_QUEUE,            MSG_ACT_QUEUE,             3, PK_BOOLEAN,
    ACTION_DROP,            MSG_ACT_DROP,             1, PK_BOOLEAN,
    ACTION_LOCK_RECORD,        MSG_ACT_LOCK_RECORD,     5, PK_BOOLEAN,
    ACTION_FREE_RECORD,        MSG_ACT_FREE_RECORD,     3, PK_BOOLEAN,
    ACTION_ADD_NOTIFY,        MSG_ACT_ADD_NOTIFY,         1, PK_BOOLEAN,
    ACTION_REMOVE_NOTIFY,    MSG_ACT_REMOVE_NOTIFY,     1, PK_BOOLEAN,
    ACTION_SERIALIZE_DISK,    MSG_ACT_SERIALIZE_DISK,     0, PK_BOOLEAN,
    ACTION_GET_DISK_FSSM,    MSG_ACT_GET_DISK_FSSM,     0, PK_BOOLEAN,
    ACTION_FREE_DISK_FSSM,    MSG_ACT_FREE_DISK_FSSM,     0, PK_BOOLEAN,
    /*
      *        Our final table entry is used as a sentinel -- we key off the
     *        final packet message as an indication that we're finished
     *        searching the table.
      */
    0,                        LAST_PACK_MSG,             4, PK_2OK | PK_RAW
};

#define NUM_PACKETS        (sizeof(PacketTable) / sizeof(PacketTable[0]))

/*****************************************************************************
 *
 *        Start of functions!
 *
 *****************************************************************************/

/*
 *        InitPatches()
 *
 *        Sets up the library pointers and makes sure all the patch
 *        code vectors are initialised properly.
 *
 *        Also allocates memory for the patches (if necessary)
 *
 *        Returns TRUE for success, FALSE for failure.
 */
int InitPatches(void)
{
    struct PatchInitTable *pi;
    Patch *p;
    int i;

    /*
     *        Before doing anything else, do a quick check to ensure that
     *        the patch code in PATCHCODE.S agrees with the equivalent patch
     *        structure defined in this file.
     */
    if (CODESIZE != PatchCode_Size || STACKADJUST != PatchCode_StackAdjust) {
        Printf("In patches.c, adjust CODESIZE by %ld and STACKADJUST by %ld\n",
                PatchCode_Size-CODESIZE, PatchCode_StackAdjust-STACKADJUST);
        return (FALSE);
    }

    LibList[DOS_LIB]        = DOSBase;
    LibList[EXEC_LIB]        = SysBase;
    LibList[INTUITION_LIB]    = IntuitionBase;
    LibList[GRAPHICS_LIB]    = GfxBase;
    LibList[ICON_LIB]        = IconBase;

    /*
     *        First, let's calculate our ROM start and end address.
     *        We do this by getting the address pointed to by the
     *        Open LVO vector in exec.library and rounding it down
     *        to the nearest 512K
     */
    RomStart = (*((ULONG *)(((char *)SysBase) + LIB_OPEN + 2))) & 0xFFF80000;
    RomEnd   = RomStart + 0x7FFFF;

    /*
     *        Now see if the patches were already installed by an earlier
     *        version of SnoopDos.
     */
    Forbid();
    PatchAnchor = (PatchAnchorData *)FindSemaphore(PATCHES_NAME);
    if (!PatchAnchor) {
        /*
         *        Patches weren't found, so allocate a new set and initialise
         *        it with our patch code.
         */
        PatchAnchor = AllocMem(sizeof(PatchAnchorData) + PatchInitSize,
                               MEMF_ANY | MEMF_CLEAR);
        if (!PatchAnchor) {
            Permit();
            return (FALSE);
        }
        strcpy(PatchAnchor->name, PATCHES_NAME);
        PatchAnchor->sem.ss_Link.ln_Name = PatchAnchor->name;
        PatchAnchor->sem.ss_Link.ln_Pri  = 0;
        AddSemaphore(&PatchAnchor->sem);
    }
    /*
     *        Now PatchAnchor points to our patch list in memory -- copy over
     *        our patch code and initialised data accordingly.
     */
    PatchList = PatchAnchor->patchdata;
    for (pi = PatchInit+1, p = PatchList+1; pi->offset; p++, pi++) {
        memcpy(p->code, PatchCode_Start, CODESIZE);
        p->library        = pi->library;
        p->offset        = pi->offset;
        p->newfunc        = pi->newfunc;
        p->stackneeded    = CurSettings.StackLimit;
        p->sysbase        = SysBase;
    }
    CacheClearU();    /* Invalidate cache for code we just built */
    Permit();

    /*
     *        Now initialise other variables associated with the patch code
     */
    SnoopTask    = SysBase->ThisTask;
    InputTask    = FindTask("input.device");
    InitRamLibPatch();
    InitSemaphore(&PatternBufSem);
    InitSemaphore(&PatternCacheSem);
    InitSemaphore(&TaskCacheSem);
    InitSemaphore(&DosDeviceSem);
    InitSemaphore(&PauseSem);
    InitSemaphore(&PacketSem);

    UpdateDeviceList(SCANDEV_IMMEDIATE);

    NewList(&PatternList);
    for (i = 0; i < NUM_PCACHE_ENTRIES; i++)
        AddHead(&PatternList, (Node *)&PCacheEntries[i]);

    NewList(&PacketWaitList);
    NewList(&PacketFreeList);
    for (i = 0; i < NUM_PACKET_ENTRIES; i++)
        AddHead(&PacketFreeList, (Node *)&PacketEntries[i]);

    NewEventSig = AllocSignal(-1);
    if (NewEventSig == -1)
        return (FALSE);
    NewEventMask = 1 << NewEventSig;

    /*
     *        Signal bit used to tell main task to rescan device list because
     *        a device was added (or removed?)
     */
    ScanDosListSig = AllocSignal(-1);
    if (ScanDosListSig == -1)
        return (FALSE);
    ScanDosListMask = 1 << ScanDosListSig;

    /*
     *        Now create a background process to handle process matching.
     *        We run this at a high priority to ensure quick response.
     *
     *        We first of all initialise our pattern port, and set it
     *        to NOT signal our task when a message arrives. This ensures
     *        that if, for some reason, our new process doesn't run
     *        until after someone tries to send it a message, nothing
     *        bad will happen (e.g. signalling a task at 0x0000)
     *
     *        The background process itself will replace this with
     *        PA_SIGNAL to make things work normally again.
     */
    NewList(&BackgroundPort.mp_MsgList);
    BackgroundPort.mp_Flags = PA_IGNORE;
    BackgroundProc = CreateNewProcTags(NP_Entry,     BackgroundProcCode,
                                          NP_Name,      BACKGROUND_NAME,
                                       NP_Priority,  5,
                                          TAG_DONE);

    return (BackgroundProc != NULL);
}

/*
 *        UpdatePatches()
 *
 *        Scans the list of patches, updating our behaviour as follows.
 *        This means:
 *
 *            - Any patch that's currently active and which has been flagged
 *              as inactive should be disabled if possible (i.e. origfunc
 *              set to NULL).
 *
 *            - Any patch that's currently inactive and which has been flagged
 *              as active should be enabled if possible (i.e. origfunc set
 *              to point to the original function).
 *
 *        If we are currently Disabled, then all patches are made inactive.
 *
 */
void UpdatePatches(void)
{
    Patch *p;

    if (!PatchList)
        return;

    if (MonPackets || ShowAllPackets)
        UpdateDeviceList(SCANDEV_IMMEDIATE); /* Keep device list up to date */

    Forbid();            /* Don't even think about letting anyone else run! */

    /*
     *        Update status of pair functions to reflect the master
     *        function's status
     */
    PatchList[GID_READTOOLTYPES2].enabled    =
                            PatchList[GID_READTOOLTYPES].enabled;
    PatchList[GID_LOADSEG2].enabled            =
                            PatchList[GID_LOADSEG].enabled;
    PatchList[GID_GETVAR2].enabled            =
                            PatchList[GID_GETVAR].enabled;
    PatchList[GID_SETVAR2].enabled            =
                            PatchList[GID_SETVAR].enabled;

    for (p = PatchList+1; p->offset; p++) {
        void *lib        = LibList[p->library];
        int func_enabled = (Disabled ? PATCH_DISABLED : p->enabled);

        p->stackneeded     = CurSettings.StackLimit;    /* Update this */

        if (!lib)            /* Skip over any libraries we couldn't open */
            continue;

        if (p->origfunc == NULL && func_enabled != PATCH_DISABLED) {
            /*
             *        Okay, we want to enable this function.
             */
            p->origfunc = (FuncPtr)SetFunction(lib, p->offset, (FuncPtr)p);
        } else if (p->origfunc && func_enabled == PATCH_DISABLED) {
            /*
             *        Okay, we want to disable this function. However, we
             *        may not be able to do this cleanly, if it's been
             *        since patched by someone else. Thus, if our attempt
             *        to unpatch it doesn't return a pointer to our replacement
             *        code, we have to leave the patch installed. However, it
             *        will be re-tried automatically the next time someone
             *        calls this function.
             */
            FuncPtr curfunc = (FuncPtr)SetFunction(lib, p->offset, p->origfunc);

            if (curfunc != (FuncPtr)p) {
                /*
                 *        Uhoh -- someone else patched us!
                 */
                SetFunction(lib, p->offset, (FuncPtr)curfunc);
            } else {
                /*
                 *        We unpatched successfully, so zero pointer
                 */
                p->origfunc = NULL;
            }
        }
    }
    /*
     *        We disable stack monitoring for the PutMsg() patch because
     *        we need to catch the return packet from small-stack processes
     *        like RAM: etc. Instead, that patch does its own stack checking.
     */
    PatchList[GID_SENDREXX].stackneeded = 0;

    CacheClearU();    /* Just to be safe */
    Permit();
    /*
     *        Finally, check if we've disabled packet monitoring and
     *        there are some outstanding packets that have not yet had
     *        return values assigned. Free them all as appropriate
     */
    if (!MonPackets && !ShowAllPackets)
    {
        for (;;) {
            WaitPacket *wp;
            Event *ev;
            LONG  seqnum;

            ObtainSemaphore(&PacketSem);
            if (IsListEmpty(&PacketWaitList)) {
                ReleaseSemaphore(&PacketSem);
                break;
            }
            wp        = (WaitPacket *)RemHead(&PacketWaitList);
            AddHead(&PacketFreeList, (Node *)wp);
            ev       = wp->event;
            seqnum = wp->eventnum;
            ReleaseSemaphore(&PacketSem);

            ObtainSemaphore(&BufSem);
            if (seqnum >= RealFirstSeq) {
                ev->status = ES_READY;
                Signal(SnoopTask, NewEventMask);
            }
            ReleaseSemaphore(&BufSem);
        }
    }
}

/*
 *        CleanupPatches()
 *
 *        Frees any resources allocated when initialising this module. Also
 *        disable any patches that are still active.
 */
void CleanupPatches(void)
{
    static int unpatchtries = 0;

    if (PatchList) {
        struct PatchInitTable *pi;
        Patch *p;

        for (p = PatchList+1; p->offset; p++)
            p->enabled = PATCH_DISABLED;
        UpdatePatches();

        /*
         *        Now our patches have been disabled, and it's time to
         *        ensure nobody got left inside our code. We do this by
         *        checking that all the usecounts are set to zero, and if
         *        they're not, giving the user the option of continuing
         *        to try, or exiting.
         *
         *        Before we do this, however, we record all the functions
         *        which still have a usecount > 0 -- this way, if someone
         *        else runs SnoopDos while we are checking and installs
         *        a new set of patches in the patchtable, and enables
         *        some additional functions, we don't have to check that
         *        ALL usage counts are zero, only those which were non-zero
         *        at the start of the loop.
         *
         *        (That is, we ignore any usage counts which are results of
         *        functions being re-enabled by the new SnoopDos -- typically,
         *        there will only be one or two functions at most to be
         *        checked.)
         *
         *        For convenience, we re-use the PatchInit list to hold the
         *        exit "usage" states for each function -- we won't be needing
         *        it any more.
         */
        for (p = (PatchList+1), pi = (PatchInit+1); p->offset; p++, pi++)
            pi->offset = p->usecount;

        for (;;) {
            for (p = (PatchList+1), pi = (PatchInit+1); p->offset; p++, pi++) {
                if (pi->offset > 0) {
                    if (p->usecount > 0)
                        break;
                    pi->offset = 0;    /* No longer active, so mark as done */
                }
            }
            if (p->offset) {
                /*
                 *        Couldn't unpatch, so go around the loop and try
                 *        again. After about 8-10 seconds, we warn the user
                 *        that we're still trying.
                 */
                unpatchtries++;
                if (unpatchtries == 5) {
                    char errorbuf[400];

                    mysprintf(errorbuf, MSG(MSG_ERROR_UNPATCH),
                              GetFuncName(p - PatchList));
                    ShowError(errorbuf);
                }
                Delay(2*50);        /* Wait 2 seconds before next try */
            } else
                break;
        }
    }
    if (BackgroundProc) {
        /*
         *        Send a terminate message to the pattern process and wait
         *        for it to respond
         */
        PatternMsg pmsg;

        pmsg.type                = QUIT_MSG;
        pmsg.sigmask             = SIGF_SINGLE;
        pmsg.task                 = SysBase->ThisTask;
        pmsg.msg.mn_Node.ln_Name = NULL;

        SetSignal(0, SIGF_SINGLE);        /* Ensure signal is clear first */
        PutMsg(&BackgroundPort, &pmsg);    /* Send quit message to process    */
        Wait(SIGF_SINGLE);                /* Wait for acknowledgement        */
    }
    if (NewEventSig    != -1) FreeSignal(NewEventSig),    NewEventSig    = -1;
    if (ScanDosListSig != -1) FreeSignal(ScanDosListSig), ScanDosListSig = -1;
}

/*
 *        InitRamLibPatch()
 *
 *        Attempts to patch the ramlib process so that it no longer uses
 *        a message port with the signal bit set to SIGB_SINGLE (which
 *        is asking for trouble if you call any functions that use
 *        semaphores, since a SIGB_SINGLE can be generated by a message
 *        arriving at the message port while waiting for the semaphore,
 *        causing all hell to break loose -- the semaphore appears to be
 *        obtained while in fact it's still in use by someone else).
 */
void InitRamLibPatch(void)
{
    unsigned char *ramdata;
    int i;

    RealRamLibTask = FindTask("ramlib");
    if (NoPatchRamLib || !RealRamLibTask) {
        /*
         *        Not patching ramlib, so instead, install our bypass patch
         *        that stops us from monitoring any ramlib tasks so that
         *        we won't get crashed.
         */
        RamLibTask = RealRamLibTask;
    } else {
        /*
         *        Patch ramlib itself so that it doesn't use SIGF_SINGLE
         *        any more.
         */
        ramdata = (void *)SysBase->ex_RamLibPrivate;
        if (!ramdata) {
            /*
             *        You never know ... this field may no longer exist. If
             *        it doesn't, then assume the bug no longer exists either
             *        and exit.
             */
            return;
        }
        for (i = 0x20; i < 0x50; i += 2) {
            struct MsgPort *ramport = (struct MsgPort *)(ramdata + i);

            /*
             *        Depending on the Kickstart version (V37 through V40)
             *        the ramlib message port lies somewhere in the range
             *        0x30 to 0x50 of the ramlib's private area. We do
             *        some integrity checks on the port to make sure it's
             *        not just a lucky hit. If some future SetPatch fixes
             *        this, then we will never find a match, which suits
             *        us fine.
             */
            if (ramport->mp_Flags   == 0            &&
                ramport->mp_SigBit  == SIGB_SINGLE    &&
                ramport->mp_SigTask == RealRamLibTask)
            {
                /*
                 *        Now patch ramlib's message port so it won't use
                 *        SIGB_SINGLE any more. This is a little tricky, since
                 *        ramlib process will be in the middle of WaitPort()
                 *        and WaitPort() won't return until a message arrives at
                 *        the port. Essentially, we can only change the port's
                 *        message bit while we are sure that the ramlib process
                 *        is NOT in a WaitPort(). We do this by bumping our
                 *        process priority up to 127 temporarily, making the
                 *        call, and then restoring it.
                 *
                 *        Since we're at a higher priority than ramlib, then
                 *        as soon as ramlib responds to the message, it will
                 *        be switched out (in the Ready state) before it has a
                 *        chance to call WaitPort() and go back to sleep again.
                 */
                ULONG oldpri;

                Forbid();
                oldpri = SetTaskPri(SysBase->ThisTask, 127);
                OpenLibrary("ramlib-patch.library", 0);    /* Wake-up ramlib */
                ramport->mp_SigBit = SIGBREAKB_CTRL_E;
                SetTaskPri(SysBase->ThisTask, oldpri);
                Permit();
                break;
            }
        }
    }
}

/*
 *        UpdateDeviceList(method)
 *
 *        Updates the DOS device list. This is used to keep an internal list
 *        of all the task IDs of DOS handlers so we can quickly determine
 *        if a given ID belongs to a handler or not.
 *
 *        This should be called at least once, and ideally every now and
 *        again, so that new devices added to the DOS list can be detected
 *        and old ones ignored.
 *
 *        The method can be SCANDEV_IMMEDIATE, to immediately scan the device
 *        list, or SCANDEV_DELAY to wait for a second before updating. The
 *        delay is because the patch that signals us to rescan (AddDosEntry)
 *        happens before the device is actually fully initialised, so we need
 *        to give it a little extra time to get going.
 *
 *        It's not critical if we don't give it enough time, it just means
 *        that the new device won't appear in the list after all -- a bit
 *        annoying for people using the packet debugger to help debug a
 *        device they keep mounting interactively.
 */
void UpdateDeviceList(int method)
{
    struct DosList *dlist;
    int i = 0;

    if (method == SCANDEV_DELAY)
        Delay(50);

    ObtainSemaphore(&DosDeviceSem);
    dlist = LockDosList(LDF_DEVICES | LDF_READ);
    while ((dlist = NextDosEntry(dlist, LDF_DEVICES))
             && i < (MAX_DOS_DEVICES-1))
    {
        if (dlist->dol_Task)
            DeviceTaskList[i++] = dlist->dol_Task->mp_SigTask;
    }
    UnLockDosList(LDF_DEVICES | LDF_READ);
    DeviceTaskList[i] = 0;
#if 0
    Printf("New device list:\n");
    for (i = 0; DeviceTaskList[i]; i++)
        Printf("    %2ld = %s\n", i, DeviceTaskList[i]->tc_Node.ln_Name);
#endif
    ReleaseSemaphore(&DosDeviceSem);
}

/*
 *        SetPattern(string, ignorewb)
 *
 *        Sets the current pattern to the given string (possibly containing
 *        wildcards). If ignorewb is true, then the pattern is modified to
 *        also exclude any processes with the names Workbench, Shell Process
 *        or Background CLI.
 */
void SetPattern(char *pattern, int ignorewb)
{
    PatternCache *pc;
    char *p;

    if (*pattern == '\0' && !ignorewb) {
        PatternEnabled = 0;
        return;
    }
    ObtainSemaphore(&PatternCacheSem);
    ObtainSemaphore(&PatternBufSem);
    PatternEnabled = 0;

    /*
     *        Now, update our pattern string. If the pattern string is empty,
     *        we disable patterns. If the pattern string contains no wildcards,
     *        we enable patterns but disable wildcard patching (this is much
     *        faster, since it can be done in the patch's task, rather than
     *        having to call back to the main routine).
     *
     *        We allocate both pattern semaphores: the Cache semaphore to
     *        ensure that no pattern code can execute when PatternEnabled
     *        is zero, and the buffer semaphore to ensure that the pattern
     *        process doesn't try to do pattern matching while we are
     *        building the new pattern string.
     *
     *        We need to be careful to get the cache semaphore BEFORE we get
     *        the pattern buffer semaphore, otherwise we could deadlock if
     *        a patch decided to check a pattern at just the wrong time.
     */
    if (ignorewb) {
        if (*pattern == '\0')
            strcpy(PatternString, PAT_EASY_EXCLUDE);
        else
            mysprintf(PatternString, PAT_COMPLEX_EXCLUDE, pattern);
    } else
        strcpy(PatternString, pattern);

    /*
     *        Now, due to a bug in AmigaDOS's ParsePatternNoCase, we
     *        have to convert the string to upper case first. (The bug
     *        is that character classes like [a-z] will never match anything,
     *        only [A-Z] will work. Since it's case insensitive for
     *        everything else, we simply convert everything to upper case.)
     */
    for (p = PatternString; *p; p++) {
        if (*p >= 'a' && *p <= 'z')
            *p &= 0x5F;
    }
    PatternWildcard = ParsePatternNoCase(PatternString,
                                         PatternBuf, PAT_BUF_LEN);

    if (PatternWildcard != -1)    /* Only enable patterns if successful */
        PatternEnabled = 1;

    /*
     *        Regardless of what happened, invalidate the pattern cache
     *        to force a new match for each task name.
     */
    FORLIST(&PatternList, pc)
        pc->task = NULL;

    ReleaseSemaphore(&PatternBufSem);
    ReleaseSemaphore(&PatternCacheSem);
}

/*
 *        FlushWaitingPackets(void)
 *
 *        Flushes any packets currently in the waiting packets queue
 *        (marking them as missed). Usually called after packet monitoring
 *        has been disabled, in case there were any half-completed packets
 *        in the queue.
 */
void FlushWaitingPackets(void)
{
    WaitPacket *wp;
    int flushed = 0;

    ObtainSemaphore(&PacketSem);
    wp = HeadNode(&PacketWaitList);
    while (NextNode(wp)) {
        ULONG seqnum = wp->eventnum;
        Event *ev    = wp->event;

        Remove((Node *)wp);
        AddHead(&PacketFreeList, (Node *)wp);
        ReleaseSemaphore(&PacketSem);    /* Never lock two sem's at once! */
        ObtainSemaphore(&BufSem);
        if (seqnum >= RealFirstSeq) {
            ev->result = MSG(MSG_RES_MISSED);
            ev->status = ES_READY;
            flushed    = 1;
        }
        ReleaseSemaphore(&BufSem);
        ObtainSemaphore(&PacketSem);
        wp = HeadNode(&PacketWaitList);
    }
    ReleaseSemaphore(&PacketSem);

    if (flushed)
        Signal(SnoopTask, NewEventMask);
}

/*
 *        LoadFuncSettings(FuncSets)
 *
 *        Downloads the values in the passed-in FuncSettings array to the
 *        various local structures that require them.
 */
void LoadFuncSettings(FuncSettings *func)
{
    Patch *p;
    int i;

    if (!PatchList)
        return;

    Forbid();
    for (p = PatchList+1, i = 1; p->offset; p++, i++)
        p->enabled = ((func->Opts[i] && !Disabled) ?
                            PATCH_ENABLED : PATCH_DISABLED);
    /*
     *        A bit of a hack -- the PutMsg() function is needed to monitor
     *        three individual patches: SendRexx, Monitor Packets, and
     *        Packet Debugger. We do the check for the last two here.
     */
    if ((func->Opts[GID_MONPACKETS] || func->Opts[GID_MONALLPACKETS]) &&
         !Disabled)
    {
        PatchList[GID_SENDREXX].enabled    = PATCH_ENABLED;
        PatchList[GID_ADDDOSENTRY].enabled = PATCH_ENABLED;
    } else {
        PatchList[GID_ADDDOSENTRY].enabled = PATCH_DISABLED;
        FlushWaitingPackets();
    }
    UpdatePatches();
    Permit();
    SetPattern(func->Pattern, func->Opts[GID_IGNOREWB]);
}

/*
 *        BackgroundProcCode()
 *
 *        This function is called as a separate process. It is used
 *        to service requests for pattern matching by patched code.
 *        We do this in a separate process to ensure we have enough
 *        stack to perform the pattern matching (pattern matching can
 *        be very stack-intensive.)
 *
 *        This process is also used to do pathname expansion when we
 *        are monitoring packets -- this is needed for both the
 *        ShowAllPaths option and monitoring of the ACTION_MAKE_LINK packet.
 *
 *        We keep going until we get a QUIT_MSG from the main task,
 *        at which point we exit.
 */
void __saveds BackgroundProcCode(void)
{
#if DEBUG_PATTERN
    BPTR dbfile = Open("CON:100/100/400/100/Pattern/WAIT/AUTO/CLOSE",
                       MODE_OLDFILE);
#define DBP(s)    FPrintf s
#else
#define DBP(s)
#endif

    Task  *quittask;
    ULONG  quitsig;
    int    done = 0;

    /*
     *        Our first task is to re-route the message port allocated
     *        on our behalf by the main process so that it points to us.
     *        We also re-enable signals on incoming messages to ensure
     *        we are correctly interrupted.
     */
    BackgroundPort.mp_SigTask = SysBase->ThisTask;
    BackgroundPort.mp_SigBit  = AllocSignal(-1);    /* Better not fail!        */
    BackgroundPort.mp_Flags   = PA_SIGNAL;            /* Allow signalling now    */
    DBP((dbfile, "Started pattern debug code\n"));

    while (!done) {
        /*        Now handle all pattern messages queue on the pattern port.
         *        Unlike normal messages, we don't simply reply to these
         *        with ReplyMsg(); instead, we signal the indicated task
         *        using the signal bit specified in the message.
         *
         *        This is because the sender may not have an available
         *        signal bit to use to receive the reply so it uses a
         *        system bit which is guaranteed to be unused.
         *
         *        Note that we grab the pattern semapore while we process
         *        the messages; this stops the mainline code from updating
         *        the middle of the buffer while we are doing a comparison.
         */
        PatternMsg      *pmsg;
        NameFromLockMsg *lmsg;

        WaitPort(&BackgroundPort);

        ObtainSemaphore(&PatternBufSem);
        while ((pmsg = (void *)GetMsg(&BackgroundPort)) != NULL) {
            DBP((dbfile, "Got a message, type = %ld!\n", pmsg->type));
            switch (pmsg->type) {

                case QUIT_MSG:
                    /*
                     *        We've been told to quit by the main task, so
                     *        set some variables appropriately. We flush
                     *        the remaining messages in the queue first
                     *        just to be safe (we wouldn't want to leave
                     *        anyone hanging, now, would we?)
                     */
                    PatternEnabled    = 0;    /* Safety first */
                    done             = 1;
                    quittask        = pmsg->task;
                    quitsig          = pmsg->sigmask;
                    break;

                case PATTERN_MSG:
                    DBP((dbfile, "Got a pmatch from %s\n", pmsg->name));
                    if (PatternEnabled)
                        pmsg->match = MatchPatternNoCase(PatternBuf,
                                                         pmsg->name);
                    else
                        pmsg->match = 1; /* If disabled, everything matches */

                    Signal(pmsg->task, pmsg->sigmask);
                    break;

                case PATHEXPAND_MSG:
                    lmsg         = (NameFromLockMsg *)pmsg;
                    lmsg->newbuf = MyNameFromLock(lmsg->lock, lmsg->filename,
                                                  lmsg->buf,  lmsg->maxlen);
                    Signal(lmsg->task, lmsg->sigmask);
                    break;
            }
        }
        ReleaseSemaphore(&PatternBufSem);
    }

#if DEBUG_PATTERN
    DBP((dbfile, "Quitting...\n"));
    Close(dbfile);
#endif

    /*
     *        Now cleanup and exit from this task. We need to Forbid()
     *        before we signal the main task that we're ready to quit,
     *        since otherwise the main task might go ahead and unload
     *        us before we have a chance to execute the last few lines
     *        in the function (e.g. if the main task is running at a
     *        higher priority than we are).
     */
    Forbid();
    FreeSignal(BackgroundPort.mp_SigBit);
    Signal(quittask, quitsig);
}

/*
 *        CheckPattern(name, namelen)
 *
 *        Checks if our task's name has been masked out by the
 *        user, using our current AmigaDOS pattern string.
 *
 *        We can't call the DOS pattern match function directly, due to
 *        stack limitations (the caller may not have a very big stack).
 *        So, we maintain a cache of recently used tasks -- the first
 *        task on the list is always the most recently monitored task.
 *
 *        If a task doesn't appear on the list, or if it appears on the
 *        list but its name has changed, then we send a message to the
 *        main SnoopDos task asking it to check the pattern. We also
 *        add the result of this check to our cache for future calls.
 *
 *        Sending a message to another task from within a patch is tricky;
 *        more specifically, receiving the acknowledgement back from the
 *        main task is tricky. This is because we don't know what signal
 *        bits the caller might be using, and so we can't just grab one.
 *        We could use AllocSignal(), but then what if the caller has no
 *        free signal bits?
 *
 *        Our solution (not necessarily the best) is to use the reserved
 *        exec signal bit SIGB_SINGLE. This is used for semaphore operations,
 *        among others, and is only ever used while waiting for a single
 *        event to happen. Thus, when our code is reached, we know this
 *        bit is not in use and thus we can use it ourselves.
 *
 *        Returns true if no pattern is set, or if the pattern matches
 *        the current task name. Returns false otherwise.
 *
 */
int CheckPattern(char *taskname, int namelen)
{
    PatternCache *pc;
    Task *thistask = SysBase->ThisTask;
    PatternMsg pmsg;

    if (!PatternEnabled)
        return (TRUE);

    if (!PatternWildcard)
        return (stricmp(taskname, PatternString) == 0);

    namelen = MIN(namelen, PC_NAMELEN-1);

    /*
     *        Got a pattern, so search our cache list
     */
    ObtainSemaphore(&PatternCacheSem);
    FORLIST(&PatternList, pc)
        if (pc->task == thistask)
            break;

    /*
     *        Okay, now pc is either the matching task, or else a pointer
     *        to the end of our list.
     */
    if (NextNode(pc) && pc->task == thistask) {
        /*
         *        We broke out of the loop since we matched the task.
         *        Now check if the name matches too.
         */
        if (strncmp(pc->name, taskname, namelen) == 0) {
            /*
             *        We're the same. Move this node to the start of
             *        the list, and return the appropriate state.
             */
            Remove((Node *)pc);
            AddHead(&PatternList, (Node *)pc);
            ReleaseSemaphore(&PatternCacheSem);
            return (pc->match);
        }
        /*
         *        The name is different but the Task ID is the same --
         *        most likely, someone ran a new CLI command. Thus, use
         *        this cache entry for our new task name and fall through.
         */
    } else {
        /*
         *        We didn't match a task so grab one from the end of the
         *        list and use that instead.
         */
        pc         = TailNode(&PatternList);
        pc->task = thistask;
    }

    /*
     *        Move the node to the start of the list to stop it being flushed
     *        any time soon, and update the name to match our own name.
     */
    Remove((Node *)pc);
    AddHead(&PatternList, (Node *)pc);
    strncpy(pc->name, taskname, namelen);
    pc->name[namelen] = 0;
    ReleaseSemaphore(&PatternCacheSem);

    /*
     *        Now send a message to the main task asking it to perform a name
     *        match for us. We need to be careful to make sure our pmsg won't
     *        be confused with a DOS packet by our PutMsg() patch -- we do
     *        this by NULLing out the name field.
     */
    pmsg.type                = PATTERN_MSG;
    pmsg.name                 = taskname;
    pmsg.sigmask             = SIGF_SINGLE;
    pmsg.task                 = thistask;
    pmsg.msg.mn_Node.ln_Name = NULL;

    SetSignal(0, SIGF_SINGLE);        /* Ensure signal is clear first        */
    PutMsg(&BackgroundPort, &pmsg);    /* Send request to background task    */
    Wait(SIGF_SINGLE);                /* Wait for acknowledgement            */
    pc->match = pmsg.match;            /* And save result in cache            */

    return (pmsg.match);
}

/*
 *        GetVolName(lock, buf, maxlen)
 *
 *        Copies the volume name associated with lock into the buffer,
 *        with terminating ':'. If lock is NULL, the volume address is
 *        taken directly from volume.
 *
 *        If UseDevNames is true, the device list is searched looking
 *        for the device node associated with the volume node (i.e. two
 *        nodes sharing the same task address).
 *
 *        WARNING: This function must not be called from within a DOS
 *                 device handler due to potential deadlock errors!
 *
 */
void GetVolName(BPTR lock, char *buf, int maxlen)
{
    struct DeviceList *vol;
    struct DosList *dl;
    int gotdev = 0;

    if (lock == NULL) {
        NameFromLock(lock, buf, maxlen);
        return;
    }
    vol = BTOC(((struct FileLock *)BTOC(lock))->fl_Volume);

    if (UseDevNames == 0 || vol->dl_Task == NULL) {
        /*
         *        Use volume name, especially if the volume isn't currently
         *        mounted!
         */
        UBYTE *volname = BTOC(vol->dl_Name);
        int len = MIN(maxlen-2, *volname);

        memcpy(buf, volname+1, len);
        buf[len++] = ':';
        buf[len] = '\0';
        return;
    }

    /*
     *        The user wants the device name. The only way to obtain this
     *        is to search the device list looking for the device node with
     *        the same task address as this volume.
     */
    dl = LockDosList(LDF_DEVICES | LDF_READ);
    while (dl = NextDosEntry(dl, LDF_DEVICES)) {
        if (dl->dol_Task == vol->dl_Task) {
            /*
             *        Found our task, so now copy device name
             */
            UBYTE *devname = BTOC(dl->dol_Name);
            int len = MIN(maxlen-2, *devname);

            memcpy(buf, devname+1, len);
            buf[len++] = ':';
            buf[len] = '\0';
            gotdev = 1;
            break;
        }
    }
    UnLockDosList(LDF_DEVICES | LDF_READ);
    if (!gotdev)
        strcpy(buf, "???:");
}

/*
 *        MyNameFromLock(lock, filename, buf, maxlen)
 *
 *        This is a custom version of the DOS function NameFromLock()
 *        which expands a disk lock into a full path.
 *
 *        Our version adds the following features. The device name will be
 *        given as either the physical device (like DH0:) if UseDevNames
 *        is true, or the volume name (like System3.0:) if UseDevNames is
 *        false.
 *
 *        If filename is non-NULL, then it will be appended to the lock
 *        path. If filename contains path info, then this will be taken
 *        into account when generating the lock, so that an absolute path
 *        in filename will not have any effect, and a relative filename
 *        (like //directory) will cause the original lock to be ParentDir()'d
 *        twice before being resolved.
 *
 *        This function can't fail. In the event of an error (string too
 *        long, or something like that), the buffer will be filled accordingly.
 *        It is assumed that the buffer will always be big enough to hold short
 *        error messages or a volume name.
 *
 *        Returns a pointer to the path (which will not necessarily be at
 *        the start of the buffer, but is guaranteed null-terminated.)
 *        Note that it's even possible that the pointer returned will be
 *        to the original filename if no path expansion was required.
 *
 *        New: We now preserve the IoErr() that was present on entry, since
 *        it may have been set by the calling function if OnlyShowFails is
 *        true. Otherwise, IoErr() will be screwed up by the operations we
 *        do here (e.g. SAS/C deleting a non-existent file when OnlyShowFails
 *        is true).
 *
 *        WARNING: This function must not be called from within a DOS
 *                 device handler due to potential deadlock errors!
 */
char *MyNameFromLock(BPTR lock, char *filename, char *buf, int maxlen)
{
    Process *myproc = (Process *)SysBase->ThisTask;
    int pos = maxlen - 1;
    D_S(fib, struct FileInfoBlock);
    LONG savedioerr = IoErr();
    BPTR curlock;
    BPTR newlock;
    void *savewinptr;
    char *p;
    int len;
    int skipfirstslash = 0;    /* If true, skip first slash when building name */
    int err = 0;

    /*
     *        Check for special magic filehandle
     */
    if (filename && *filename) {
        if (strcmp(filename, "*") == 0)
            return (filename);

        /*
         *        First determine if we have any work to do.
         */
        if (*filename == ':') {
            /*
             *        Got a reference relative to the root directory. Simply
             *        grab the volume (or device) name from the lock and go
             *        with that.
             */
            int len;

            GetVolName(lock, buf, maxlen);
            len = strlen(buf);
            strncat(buf+len, filename+1, maxlen-len);
            buf[maxlen-1] = '\0';
            SetIoErr(savedioerr);
            return (buf);
        }
        for (p = filename; *p; p++) {
            if (*p == ':')            /* If absolute path name, leave it alone */
                return (filename);
        }
    } else {
        /*
         *        Filename is null, so indicate we want to skip the first
         *        slash when building the directory path
         */
        skipfirstslash = 1;
    }

    savewinptr = myproc->pr_WindowPtr;
    myproc->pr_WindowPtr = (APTR)-1;        /* Disable error requesters      */

    newlock = DupLock(lock);
    if (lock && !newlock) {
        GetVolName(lock, buf, 20);
        if (filename) {
            strcat(buf, ".../");
            strcat(buf, filename);
        }
        myproc->pr_WindowPtr = savewinptr;    /* Re-enable error requesters */
        SetIoErr(savedioerr);
        return (buf);
    }
    buf[pos] = '\0';
    curlock = newlock;
    if (filename) {
        while (newlock && *filename == '/') {
            /*
             *        Handle leading /'s by moving back a directory level
             *        but nothing else
             */
            newlock = ParentDir(curlock);
            if (newlock) {
                UnLock(curlock);
                curlock = newlock;
                filename++;
            }
        }
        len = strlen(filename);
        if (len > (pos-2)) {
            memcpy(buf+2, filename+len-pos, pos-2);
            buf[0] = buf[1] = '.';
            pos = 0;
            UnLock(curlock);
        } else {
            pos -= len;
            memcpy(buf+pos, filename, len);
        }
    }

    /*
     *        At this point, we have buf containing the filename (minus any
     *        leading /'s), starting at the index given by pos. If filename
     *        was NULL or empty, then pos indexes to a \0 terminator.
     *
     *        Next, we want to pre-pend directory names to the front of
     *        the filename (assuming there _is_ a filename) until we get
     *        to the device root.
     */
    newlock = curlock;
    while (newlock) {

        if (!Examine(curlock, fib)) {
            err++;
            break;
        }
        len = strlen(fib->fib_FileName);
        if (len > (pos-3)) {
            /*
             *        Not enough room: prefix dots at start to indicate
             *        an overrun. We use pos-3 since we need one char
             *        for a possible slash and two more to accomodate a
             *        leading ".."
             */
            memcpy(buf+2, fib->fib_FileName+len-pos+3, pos-2);
            buf[0] = buf[1] = '.';
            buf[pos-1] = '/';
            pos = 0;
            break;
        }
        newlock = ParentDir(curlock);
        if (newlock) {
            UnLock(curlock);
            curlock = newlock;
            pos -= len + 1;
            memcpy(buf + pos, fib->fib_FileName, len);
            if (skipfirstslash) {
                skipfirstslash = 0;
                buf[pos+len] = '\0';
            } else
                buf[pos+len] = '/';
        }
    }
    /*
     *        Now we've built the path components; add the volume node
     *        to the beginning if possible.
     */
    if (err) {
        /*
         *        If an error occurred, the volume is probably not mounted,
         *        so we include a ".../" component in the path to show
         *        we couldn't get all the info
         */
        pos -= 4;
        memcpy(buf + pos, ".../", 4);
    }
    if (pos > 0) {
        char volname[20];
        int len;
        char *p;

        GetVolName(curlock, volname, 20);
        len = strlen(volname);
        if (len > pos) {
            p = volname + len - pos;
            len = pos;
        } else {
            p = volname;
        }
        pos -= len;
        memcpy(buf + pos, p, len);
    }
    if (curlock)
        UnLock(curlock);

    myproc->pr_WindowPtr = savewinptr;        /* Re-enable error requesters */
    SetIoErr(savedioerr);
    return (buf+pos);
}

/*
 *        AsyncNameFromLock(volname, lock, filename, dest, maxlen)
 *
 *        This is identical to the MyNameFromLock() function except that
 *        it gets the background SnoopDos process to do the path expansion
 *        instead of doinng it from within the caller's process. This is
 *        necessary if we need to expand paths and we are not sure if the
 *        caller's process mesage port is free.
 *
 *        Volname is the volume on which the lock resides. If the lock itself
 *        is NULL, then the root of the volume will be assumed and this
 *        string will be copied into the buffer as the volume name.
 *
 *        WARNING: This function must not be called from within a DOS
 *                 device handler due to potential deadlock errors!
 */
char *AsyncNameFromLock(char *volname, BPTR lock, char *filename,
                        char *buf, int maxlen)
{
    NameFromLockMsg lmsg;

    if (lock == NULL) {
        /*
         *        Do a quick scan on the filename itself to see
         *        if it contains a colon prefixed by some text;
         *        if it does, then we already have a full path.
         *        If it's just a colon, prefix it with the
         *        volume name. If it has no colon, prefix it
         *        with the volume name and a colon.
         */
        char *p;

        strcpy(buf, volname);
        if (filename) {
            if (*filename == ':') {
                strcat(buf, filename);
            } else {
                for (p = filename; *p && *p != ':'; p++)
                    ;
                if (*p)
                    strcpy(buf, filename);
                else
                    mysprintf(buf, "%s:%s", volname, filename);
            }
        }
        return (buf);
    }
    lmsg.type        = PATHEXPAND_MSG;
    lmsg.lock        = lock;
    lmsg.filename    = filename;
    lmsg.buf        = buf;
    lmsg.maxlen        = maxlen;
    lmsg.sigmask    = SIGF_SINGLE;
    lmsg.task        = SysBase->ThisTask;
    lmsg.msg.mn_Node.ln_Name = NULL;

    SetSignal(0, SIGF_SINGLE);        /* Ensure signal is clear first        */
    PutMsg(&BackgroundPort, &lmsg);    /* Send request to background task    */
    Wait(SIGF_SINGLE);                /* Wait for acknowledgement            */
    return (lmsg.newbuf);
}

#if STACK_CHECK
/*
 *        GetFreeStack()
 *
 *        Returns the amount of free space available on the calling task's
 *        stack (thanks to Ralph Babel for this).
 */
ULONG GetFreeStack(void)
{
    Process *pr = (Process *)SysBase->ThisTask;
    char *upper;
    char *lower;
    ULONG total;
    ULONG avail;

    if (pr->pr_Task.tc_Node.ln_Type == NT_PROCESS && pr->pr_CLI != NULL) {
        upper = (char *)pr->pr_ReturnAddr + sizeof(ULONG);
        total = *(ULONG *)pr->pr_ReturnAddr;
        lower = upper - total;
    } else {
        upper = (char *)pr->pr_Task.tc_SPUpper;
        lower = (char *)pr->pr_Task.tc_SPLower;
        total = upper - lower;
    }
    avail = (char *)getreg(REG_A7) - lower;
    return (avail);
}
#endif

/*
 *        CreateEvent(calladdr, seqnum, action, filename,
 *                    options, expandname [, lock] )
 *
 *        Allocates a new event for the current task and initialises
 *        almost all the fields in it accordingly.
 *
 *        seqnum is initialised to the sequence number of the new event. This
 *        is used to allow later detection of events which have scrolled off
 *        the top of the buffer.
 *
 *        filename and options are text strings, and actionid is a message ID.
 *        The storage for these will be allocated in the event buffer.
 *
 *        If expandname is EXPAND_NAME, then 'filename' is assumed to represent
 *        a real disk filename, and it will be expanded to a full path if that
 *        option is set. If expandname is NO_EXPAND, then the name is passed
 *        unchanged.
 *
 *        If expandname is neither EXPAND_NAME or NO_EXPAND, then it is
 *        interpreted as a volume name, and one additional parameter
 *        following it will be expected -- this additional parameter will
 *        be a lock on that volume. The filename will then be expanded
 *        to a full pathname on that volume. If the lock is null, then it
 *        is assumed to represent the root of the volume. The filename
 *        expansion is done by the background process, making it safe to
 *        call from within the PutMsg() patch which monitors raw packets.
 *
 *        If you pass in a NULL value for any of the three pointers, it will
 *        be made to point to a blank string.
 *
 *        If for some reason the event could not be created, returns NULL,
 *        else returns a pointer to the initialised event.
 *
 *        Possible reasons for failure include:
 *
 *            - Calling task is main SnoopDos task (!)
 *            - Calling task is not included in the match pattern
 *            - Calling task was called by a ROM function
 *            - Disk error occurred expanding filename
 *            - Out of memory allocating new event
 */
struct Event *CreateEvent(ULONG calladdr, LONG *seqnum, ULONG actionid,
                          char *filename, char *options, int expandname, ...)
{
    Task *thistask = SysBase->ThisTask;
    struct CommandLineInterface *cli;
    Event *ev;
    char *procname;
    char *strptr;
    char *action;
    char namebuf[MAX_SHORT_LEN+1];
    char pathbuf[MAX_STR_LEN+1];
    int plen = 0;
    int flen = 0;
    int olen = 0;
    int alen = 0;
    int slen = 0;
    int clinum;

    /*
     *        We ignore all calls from the main SnoopDOS process and
     *        background process, and also any nested calls made while
     *        we have the semaphore locked (which might otherwise lead
     *        to nasty trashing of the list!)
     *
     *        Also, any calls from input.device are ignored since these
     *        typically call us with layers locked, and the slightest
     *        delay could be fatal.
     */
    if (thistask == SnoopTask || thistask == (Task *)BackgroundProc
                              || thistask == BufSem.ss_Owner
                              || thistask == RamLibTask
                              || thistask == InputTask)
        return (NULL);

    /*
     *        We also ignore any calls made from ROM addresses (if this
     *        option is enabled), since this cuts down the amount of
     *        superfluos output considerably.
     *
     *        We specifically DO allow calls from within ramlib, since
     *        it's very easy to disable ramlib directly if need be (by
     *        putting ~ramlib in the match name) and ramlib does
     *        many useful operations that are convenient to monitor.
     */
    if (thistask != RealRamLibTask && !MonROMCalls &&
                              calladdr >= RomStart && calladdr <= RomEnd)
        return (NULL);

    /*
     *        Work out the correct name for our task. This will either be
     *        the task name, the process name, or the current CLI command
     *        (if the process is a CLI, _and_ is currently running a command.)
     *
     *        In addition, for CLIs, we set clinum to the CLI number. For
     *        tasks and non-CLI processes, clinum becomes zero.
     */
    procname = thistask->tc_Node.ln_Name;
    plen     = strlen(procname);
    cli         = BTOC(((Process *)thistask)->pr_CLI);
    clinum   = 0;

    if (thistask->tc_Node.ln_Type == NT_PROCESS && cli) {
        /*
         *        If we have a CLI command, we have to convert the name
         *        from a BSTR into a C string
         */
        clinum = ((Process *)thistask)->pr_TaskNum;
        if (cli->cli_Module) {
            UBYTE *cliname = BTOC(cli->cli_CommandName);
            plen = *cliname;

            if (plen) {
                if (plen > MAX_SHORT_LEN)
                    plen = MAX_SHORT_LEN;
                memcpy(namebuf, cliname+1, plen);
                namebuf[plen] = 0;
            } else {
                strcpy(namebuf, "<Unknown>");
                plen = strlen(namebuf);
            }
            procname = namebuf;
        }
    }

#if 0
    if (stricmp(procname, "ramlib") == 0) {
        KPrintF("Ramlib: Stacksize is %ld\n", GetFreeStack());
    }
#endif

    if (!CheckPattern(procname, plen))        /* Perform pattern check */
        return (FALSE);

    /*
     *        Now deal with our three strings
     */
    if (ShowPaths && filename != NULL) {
        if (expandname == EXPAND_NAME) {
            /*
             *        Expand filename to full path
             */
            filename = MyNameFromLock(((Process *)thistask)->pr_CurrentDir,
                                      filename, pathbuf, MAX_STR_LEN);
        } else if (expandname != NO_EXPAND) {
            /*
             *        Expand filename to full path using background process
             *        and the lock specified in expandname.
             */
            BPTR lock = *(ULONG *)(&expandname+1);

            filename = AsyncNameFromLock((char *)expandname, lock, filename,
                                         pathbuf, MAX_STR_LEN);
        }
    }
    plen++;
    if (ShowCLINum && clinum)
        plen += 8;                        /* Leave room for CLI display */

    action = MSG(actionid);
    alen   = strlen(action) + 1;

    if (filename)    flen = strlen(filename)    + 1;
    if (options)    olen = strlen(options)    + 1;

    if (SegTrackerActive)
        slen = MAX_SEGTRACKER_LEN;

    /*
     *        If the calling task has locked the layers of the SnoopDos
     *        screen, then we ignore all calls by that task. This prevents
     *        us deadlocking when we wait for the semaphore (while meanwhile,
     *        the SnoopDos mainline code could own the semaphore, and be
     *        waiting for the layers to be unlocked by our caller so it can
     *        render some output).
     *
     *        We Forbid() to make sure the window doesn't get closed from
     *        under our feet while we're checking it. We have to try and
     *        allocate the event while still Forbid'd since otherwise, there
     *        is a small window where the main window could open, lock the
     *        layers, and lock the semaphore, in between our check. It's
     *        unlikely, but not _that_ unlikely (especially since the main
     *        window always does an immediate redraw when it opens)
     */
    Forbid();
    if (MainWindow &&
            (MainWindow->RPort->Layer->Lock.ss_Owner   == thistask ||
             MainWindow->WScreen->LayerInfo.Lock.ss_Owner == thistask)) {
        Permit();
        return (NULL);
    }
    ev = GetNewEvent(plen + alen + flen + olen + slen);
    Permit();

    if (!ev)
        return (NULL);

    ev->action = ev->filename = ev->options = ev->result = "";

    strptr = (char *)(ev+1);

    if (ShowCLINum && clinum)
        mysprintf(strptr, "[%ld] %s", clinum, procname);
    else
        strcpy(strptr, procname);
    ev->procname  = strptr;
    strptr       += plen;

//    KPrintF("New event: %ld, %s, %s\n", ev->seqnum, procname, action); /* DB */
    if (alen) {
        strcpy(strptr, action);
        ev->action   = strptr;
        strptr          += alen;
    }
    if (flen) {
        strcpy(strptr, filename);
        ev->filename  = strptr;
        strptr        += flen;
    }
    if (olen) {
        strcpy(strptr, options);
        ev->options   = strptr;
        strptr       += olen;
    }
    if (slen) {
        ev->segname      = strptr;
        strptr       += slen;
    } else {
        ev->segname   = NULL;    /* Say no segtracker storage allocated */
    }
    // DateStamp(&ev->datestamp);
    ev->calladdr    = calladdr;
    ev->processid    = (ULONG)thistask;
    // ev->processid    = GetFreeStack();

    if (seqnum)
        *seqnum = ev->seqnum;
    return (ev);
}

/*
 *        CheckTaskRecursion()
 *
 *        Checks if the current task is already listed as being on the
 *        recursion list. If so, returns FALSE, indicating that the
 *        caller should immediately pass control back to the original
 *        function and not try and do anything else.
 *
 *        Otherwise, records the task's address in a recursion list
 *        and returns a handle. This handle should be passed back to
 *        EndTaskRecursion() when the function is complete, which will
 *        cause it to be removed from the list.
 *
 *        OpenLibrary() needs to surround its call to CreateEvent() with
 *        CheckTaskRecursion()/EndTaskRecursion. Also, GetMsg()/PutMsg() need
 *        this to check if any of the DOS packets it monitors have been
 *        generated by AmigaDOS functions we monitor.
 */
ULONG CheckTaskRecursion(void)
{
    Task *taskid = SysBase->ThisTask;
    ULONG taskhandle;
    int i;

    for (i = 1; i < NUM_CACHED_TASKS; i++)
        if (CachedTask[i] == taskid)
            return (0);

    ObtainSemaphore(&TaskCacheSem);
    taskhandle = TaskCacheIndex++;
    if (TaskCacheIndex >= NUM_CACHED_TASKS)
        TaskCacheIndex = 1;
    CachedTask[taskhandle] = taskid;
    ReleaseSemaphore(&TaskCacheSem);

    return (taskhandle);
}

/*
 *        EndTaskRecursion(taskhandle)
 *
 *        Called to remove a task from the recursion list.
 *        See CheckTaskRecursion() above.
 */
void EndTaskRecursion(ULONG taskhandle)
{
    CachedTask[taskhandle] = 0;
}

#if 0
/*
 *        TestPatch()
 *
 *        Patches a single function to try it out
 */
void TestPatch(void)
{
    extern List            EventList;            /* List of events        */
    static EventFormat evformat[50];
    static char outstr[500];
    char *formatstr = "%d %t %c %n %s %h %a %40f %o %r";
    int formatlen;

    OnlyShowFails    = 0;
    SegTrackerActive = 1;
    formatlen = ParseFormatString(formatstr, evformat, 50);

    if (!InitPatches()) {
        printf("Patch initialisation failed!\n");
        return;
    }

    PatchList[GID_OPENFILE].enabled = 1;
    UpdatePatches();
    printf("Patch now enabled!\n\n");

    FormatEvent(evformat, NULL, outstr, 0, formatlen-1);
    printf("%s\n", outstr);
    printf("%s\n", UnderlineTitles(evformat, outstr, '-'));

    for (;;) {
        ULONG mask;

        mask = Wait(SIGBREAKF_CTRL_C | NewEventMask);
        if (mask & SIGBREAKF_CTRL_C)
            break;

        if (mask & NewEventMask) {
            Event *ev;

            SetSignal(0, NewEventMask);    /* Clear signal for next time */
            FORLIST(&EventList, ev) {
                int stat = ev->status;

                if (stat == ES_UPDATING || stat == ES_READY) {
                    FormatEvent(evformat, ev, outstr, 0, formatlen-1);
                    printf("%s\n", outstr);
                    if (stat == ES_READY)
                        ev->status = ES_ACCEPTED;
                }
            }
        }
    }
    PatchList[GID_OPENFILE].enabled = 0;
    UpdatePatches();
    printf("Patch disabled\n");
    CleanupPatches();
}
#endif

/*
 *        HandlePaused(event, seqnum)
 *
 *        Should be called when pausing is enabled -- it sets the
 *        event Result code to "...." to indicate the event is about
 *        to be executed, then waits for the pausing to be turned off.
 *        If you pass in NULL as the event code, then this isn't done.
 *
 *        seqnum is the actual event number remembered by the caller,
 *        not (necessarily) the event number stored in the event. This
 *        is so that the code can check if the event has rolled off the
 *        top of the buffer or not before modifying it.
 *
 *        There are some circumstances where it is dangerous for
 *        us to pause because we are being called by a system task
 *        that is needed by the main SnoopDos program.
 *
 *        We work around this as follows. Firstly, if the caller happens
 *        to own the semaphore associated with the layer info for the
 *        window or screen containing the SnoopDos window, then we
 *        don't try and pause it since otherwise we might deadlock
 *        (the user wouldn't be able to unpause SnoopDos because that
 *        requires clicking on a button.)
 *
 *        Secondly, whenever SnoopDos itself does something that might
 *        stop it processing the main messages (e.g. show a requester,
 *        open a file, check for ASL, etc.) then pausing is temporarily
 *        turned off since we have no way of knowing whether a third
 *        party patch might be spinning off a background task to do it
 *        and the background task might try and wait on this. Bummer, eh?
 */
void HandlePaused(Event *ev, LONG seqnum)
{
    if (Paused) {
        /*
         *        Need to forbid when checking layers since otherwise the
         *        main window might close while we're reading its pointers.
         */
        int gotlock = 0;
        char *oldresmsg;

        Forbid();
        if (MainWindow) {
            struct Layer *layer;
            struct Layer_Info *li;
            Task *thistask = SysBase->ThisTask;

            layer = MainWindow->RPort->Layer;
            li    = &MainWindow->WScreen->LayerInfo;

            gotlock = (li->Lock.ss_Owner    == thistask) ||
                      (layer->Lock.ss_Owner == thistask);
        }
        Permit();
        if (gotlock)
            return;

        /*
         *        Okay, safe to proceed with pausing. We simply set the
         *        result message to indicate we're paused, signal
         *        the main task, wait for the pausing to finish, restore
         *        the result message, and return.
         */
        if (ev) {
            ObtainSemaphore(&BufSem);
            if (seqnum >= RealFirstSeq) {
                oldresmsg  = ev->result;
                ev->result = MSG(MSG_RES_PAUSE);
            }
            ReleaseSemaphore(&BufSem);
        }
        Signal(SnoopTask, NewEventMask);    /* Make sure main task updates */
        ObtainSemaphore(&PauseSem);
        ReleaseSemaphore(&PauseSem);
        if (ev) {
            ObtainSemaphore(&BufSem);
            if (seqnum >= RealFirstSeq)
                ev->result = oldresmsg;
            ReleaseSemaphore(&BufSem);
        }
    }
}

#define CheckForPause(ev,seqnum)    if (Paused)    { HandlePaused(ev, seqnum); }

/*****************************************************************************
 *
 *        Now here are all the patches for the 25 or so functions that we
 *        patch into. Most of the patches follow a similar template, and
 *        share similar lower-level functions, but are different enough to
 *        prevent us from using the same patch for several functions.
 *
 *        We always signal both before and after a particular call, so that
 *        in the event of a call causing a crash, it will still show up in
 *        the SnoopDos window.
 *
 *        The OnlyShowFails flag is used to say whether we want to monitor
 *        all calls to a function, or only those which return a failure code.
 *        If the latter, we need to call the function first before deciding
 *        whether or not to create an event to record it -- in this case, the
 *        result code remains cached for the remainder of the function. The
 *        rest of the time, we create the event and signal the main task,
 *        then call the function to get the result, and finally update the
 *        event with the result and signal the main task again.
 *
 *        Each patch that calls a function and then updates the buffer on its
 *        return must ensure that the buffer entry is has a pointer to is still
 *        valid before it updates it. It does this by remembering the sequence
 *        number of the buffer entry, and then checking that the sequence
 *        number of the first buffer entry is still <= that (i.e. the entry
 *        is still somewhere in the buffer). This is vital to ensure that
 *        innocent buffer memory isn't trashed by old events.
 *
 *****************************************************************************/

/*
 *        New_FindPort(name)
 *
 *        Searches the system port list looking for a port name
 */
ULONG ASM New_FindPort(reg_a1 char *name, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_FindPort origfunc = (FP_FindPort)PatchList[GID_FINDPORT].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_FINDPORT,
                     name, NULL, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_FindResident(name)
 *
 *        Searches the system resident list looking for a resident module
 */
ULONG ASM New_FindResident(reg_a1 char *name, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_FindResident origfunc = (FP_FindResident)
                                PatchList[GID_FINDRESIDENT].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    LONG  seqnum;

    if (SysBase->ThisTask == RealRamLibTask)
        JumpOrigFunc(0);

    if (onlyfails) {
        result = origfunc(name, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_FINDRESIDENT,
                     name, NULL, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_FindSemaphore(name)
 *
 *        Searches the system semaphore list looking for the named semaphore
 */
ULONG ASM New_FindSemaphore(reg_a1 char *name, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_FindSemaphore origfunc = (FP_FindSemaphore)
                                  PatchList[GID_FINDSEMAPHORE].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_FINDSEM,
                     name, NULL, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_FindTask(name)
 *
 *        Searches the system task list looking for the named task.
 *        We ignore calls to FindTask(0) since this is just
 *        looking for a pointer to the current task.
 */
ULONG ASM New_FindTask(reg_a1 char *name, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_FindTask origfunc = (FP_FindTask)PatchList[GID_FINDTASK].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    LONG  seqnum;

    if (name == NULL)
        return (origfunc(name, libbase));

    if (onlyfails) {
        result = origfunc(name, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_FINDTASK,
                     name, NULL, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_LockPubScreen(name)
 *
 *        Obtains a lock on the named public screen. If the name is NULL,
 *        then the caller is looking for a Lock() on the default screen,
 *        and we ignore it (otherwise we'd get loads of output).
 */
ULONG ASM New_LockPubScreen(reg_a0 char *name, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_LockPubScreen origfunc = (FP_LockPubScreen)
                                PatchList[GID_LOCKSCREEN].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    LONG  seqnum;

    if (!name)
        JumpOrigFunc(0);

    if (onlyfails) {
        result = origfunc(name, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_LOCKSCREEN,
                     name, NULL, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        Signal(SnoopTask, NewEventMask);
        CheckForPause(ev, seqnum);
        result = origfunc(name, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_OpenDevice(name, unit, ioreq, flags)
 *
 *        Opens a new device. We need to be careful with the error return
 *        for this function, since success is indicated by a return of 0!
 *
 *        N.b. Kickstart 3.1 has a space-saving hack which allows a NULL
 *        device name to be interpreted as a magic cookie indicating a
 *        particular ROM devices. We ignore such calls (especially from CON,
 *        which does it a lot!) but flag other occurrances of NULL device
 *        names as an error.
 */
ULONG ASM New_OpenDevice(reg_a0 char *name, reg_d0 long unit,
                         reg_a1 struct IORequest *ioreq,
                         reg_d1 long flags, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_OpenDevice origfunc = (FP_OpenDevice)PatchList[GID_OPENDEVICE].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    char unitstr[20];
    char *devname = name;
    LONG  seqnum;

/*
 *        Release Semaphore replacement code for debugging patch
 */
#if MONITOR_SEMAPHORE
    Semaphore *sem = (Semaphore *)name;

    if (LoadTask == SysBase->ThisTask)
        KPrintF("ReleaseSemaphore in LoadSeg: retaddr = %08lx\n", CallAddr);
    return origfunc(name, unit, ioreq, flags, libbase);
#endif

    if (onlyfails) {
        result = origfunc(name, unit, ioreq, flags, libbase);
        if (!result)
            return (result);
    }
    /*
     *        Now a workaround for a bug in CON that makes it call
     *        OpenDevice("timer.device" | NULL) very frequently.
     *        (The NULL is a space-saving shorthand which the 3.1 Kickstart
     *        interprets as a magic cookie for "timer.device" to save some
     *        ROM space).
     */
    if ((CallAddr >= RomStart && CallAddr <= RomEnd) ||
                    strcmp(SysBase->ThisTask->tc_Node.ln_Name, "CON") == 0) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(unit);
    }
    if (!devname)
        devname = MSG(MSG_NULLSTR);

    mysprintf(unitstr, MSG(MSG_OPT_DEVUNIT), unit);
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_OPENDEV,
                     devname, unitstr, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(unit);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, unit, ioreq, flags, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (!result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_OpenFont(textattr)
 *
 *        Opens a new font that's currently in memory. OpenDiskFont will
 *        call this function first before checking the disk, so patching
 *        this function catches all accesses.
 */
ULONG ASM New_OpenFont(reg_a0 struct TextAttr *textattr, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_OpenFont origfunc = (FP_OpenFont)PatchList[GID_OPENFONT].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    char *name;
    char sizestr[20];
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(textattr, libbase);
        if (result)
            return (result);
    }
    if (textattr) {
        mysprintf(sizestr, MSG(MSG_OPT_FONTSIZE), textattr->ta_YSize);
        name = textattr->ta_Name;
    } else {
        *sizestr = '\0';
        name = MSG(MSG_NULLSTR);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_OPENFONT,
                     name, sizestr, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(textattr, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_OpenLibrary(name, version)
 *
 *        Opens the named library with the specified version number.
 *
 *        We have a nasty potential for deadlock here -- CreateEvent()
 *        which we call, in turns calls DateStamp(), and DateStamp()
 *        itself calls OpenLibrary(....). So, we need to protect
 *        ourselves against a recursive call.
 *
 *        We do this by ignoring any call to open dos.library made
 *        by a call originating in ROM.
 */
ULONG ASM New_OpenLibrary(reg_a1 char *name, reg_d0 long version,
                          reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_OpenLibrary origfunc = (FP_OpenLibrary)
                               PatchList[GID_OPENLIBRARY].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    char verstr[20];
    ULONG taskhandle;
    LONG  seqnum;

    /*
     *        Check for re-entrant calling (usually caused by the
     *        DateStamp call in the GetNewEvent() code).
     *
     *        In theory, we should only need to check if the semaphore
     *        is owned by the current task. In practise, we need
     *        the additional checks to be really sure (otherwise
     *        we seem to get unexplained crashes very frequently --
     *        very mysterious and worrying).
     *
     *        We also ignore calls to open dos.library -- this is partly
     *        because it gets called by DateStamp() inside dos.library
     *        itself (so things that call DateStamp once a second, like
     *        Enforcer(), will generate loads of calls to it) and partly
     *        to avoid problems with our own CreateEvent() code calling it.
     */
    if (BufSem.ss_Owner == SysBase->ThisTask ||
        strcmp(name, "dos.library") == 0)
    {
        JumpOrigFunc(version);
    }

    if (onlyfails) {
        result = origfunc(name, version, libbase);
        if (result)
            return (result);
    }
    taskhandle = CheckTaskRecursion();
    if (!taskhandle) {
        if (!onlyfails)
            result = origfunc(name, version, libbase);
        return (result);
    }
    mysprintf(verstr, MSG(MSG_OPT_LIBVER), version);
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_OPENLIB,
                     name, verstr, NO_EXPAND);
    EndTaskRecursion(taskhandle);

    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(version);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, version, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_OpenResource(name)
 *
 *        Opens the named resource
 */
ULONG ASM New_OpenResource(reg_a1 char *name, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_OpenResource origfunc = (FP_OpenResource)
                                PatchList[GID_OPENRESOURCE].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_OPENRES,
                     name, NULL, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_FindToolType(array, tooltype)
 *
 *        Searches the tooltype array for a particular tooltype
 */
ULONG ASM New_FindToolType(reg_a0 char **array, reg_a1 char *tooltype,
                           reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_FindToolType origfunc = (FP_FindToolType)
                                PatchList[GID_READTOOLTYPES].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    char *toolname = tooltype;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(array, tooltype, libbase);
        if (result)
            return (result);
    }
    if (toolname == NULL)
        toolname = MSG(MSG_NULLSTR);

    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_FINDTOOL,
                     toolname, NULL, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(array, tooltype, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_MatchToolValue(tooltype, value)
 *
 *        Checks if a specified tooltype contains a given value
 */
ULONG ASM New_MatchToolValue(reg_a0 char *tooltype, reg_a1 char *value,
                             reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_MatchToolValue origfunc = (FP_MatchToolValue)
                                  PatchList[GID_READTOOLTYPES2].origfunc;
    int onlyfails = OnlyShowFails;
    ULONG result;
    Event *ev;
    char *toolname = tooltype;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(tooltype, value, libbase);
        if (result)
            return (result);
    }
    if (toolname == NULL)
        toolname = MSG(MSG_NULLSTR);

    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_MATCHTOOL,
                     toolname, value, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(tooltype, value, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_CurrentDir()
 *
 *        Changes current directory to somewhere else
 */
ULONG ASM New_CurrentDir(reg_d1 BPTR lock, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_CurrentDir origfunc = (FP_CurrentDir)PatchList[GID_CHANGEDIR].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    char lockbuf[MAX_LOCK_LEN+1];
    char *lockpath;
    LONG  seqnum;

    if (onlyfails)
        return origfunc(lock, libbase);        /* CurrentDir never fails */

    lockpath = MyNameFromLock(lock, NULL, lockbuf, MAX_LOCK_LEN);
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_CHANGEDIR,
                     lockpath, NULL, NO_EXPAND);
    if (!ev)
        JumpOrigFunc(0);

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    ev->status = ES_UPDATING;
    CheckForPause(ev, seqnum);
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return origfunc(lock, libbase);
}

/*
 *        New_DeleteFile()
 *
 *        Deletes a file from disk
 */
ULONG ASM New_DeleteFile(reg_d1 char *name, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_DeleteFile origfunc = (FP_DeleteFile)PatchList[GID_DELETE].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_DELETE,
                     name, NULL, EXPAND_NAME);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_Execute()
 *
 *        Executes a command from disk. Now superceded by System and RunCommand
 */
ULONG ASM New_Execute(reg_d1 char *cmdline, reg_d2 BPTR fin, reg_d3 BPTR fout,
                      reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_Execute origfunc = (FP_Execute)PatchList[GID_EXECUTE].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    char *optstr;
    LONG  seqnum;

    /*
     *        For functions that may potentially take a long time to complete,
     *        we check if they're being called from ROM straight away, so
     *        that we can exit and not hang around waiting for them if they
     *        are, even in the OnlyShowFails case.
     */
    if (!MonROMCalls && CallAddr >= RomStart && CallAddr <= RomEnd)
        JumpOrigFunc(0);

    if (onlyfails) {
        result = origfunc(cmdline, fin, fout, libbase);
        if (result)
            return (result);
    }
    if (fin == NULL)
        optstr = MSG(MSG_OPT_EXECSINGLE);
    else
        optstr = MSG(MSG_OPT_EXECBATCH);

    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_EXECUTE,
                     cmdline, optstr, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(cmdline, fin, fout, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_GetVar()
 *
 *        Inquires about the value of an environment variable
 */
ULONG ASM New_GetVar(reg_d1 char *name, reg_d2 char *buffer,
                     reg_d3 size, reg_d4 flags, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_GetVar origfunc = (FP_GetVar)PatchList[GID_GETVAR].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    char optstr[20];
    ULONG optid;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, buffer, size, flags, libbase);
        if (result != -1)
            return (result);
    }
    /*
     *        Now determine our flags. We recognise global, local
     *        or either types of variable. Binary variables are
     *        flagged with a trailing asterisk.
     */
    if        (flags & GVF_GLOBAL_ONLY)    optid = MSG_OPT_GLOBAL;
    else if ((flags & 7) == LV_ALIAS)    optid = MSG_OPT_ALIAS;
    else if (flags & GVF_LOCAL_ONLY)    optid = MSG_OPT_LOCAL;
    else                                optid = MSG_OPT_ANY;
    strcpy(optstr, MSG(optid));

    if (flags & GVF_BINARY_VAR)            strcat(optstr, "*");

    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_GETVAR,
                     name, optstr, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, buffer, size, flags, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result != -1)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_FindVar()
 *
 *        Inquires about the value of a local environment variable
 */
ULONG ASM New_FindVar(reg_d1 char *name, reg_d2 ULONG type,
                      reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_FindVar origfunc = (FP_FindVar)PatchList[GID_GETVAR2].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    ULONG optid;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, type, libbase);
        if (result)
            return (result);
    }

    if        ((type & 7) == LV_VAR)        optid = MSG_OPT_LOCAL;
    else if ((type & 7) == LV_ALIAS)    optid = MSG_OPT_ALIAS;
    else                                optid = MSG_OPT_UNKNOWN;

    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_FINDVAR,
                     name, MSG(optid), NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        Signal(SnoopTask, NewEventMask);
        CheckForPause(ev, seqnum);
        result = origfunc(name, type, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_SetVar()
 *
 *        Sets a (possibly new) variable to a particular value
 */
ULONG ASM New_SetVar(reg_d1 char *name, reg_d2 char *buffer,
                     reg_d3 size, reg_d4 flags, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_SetVar origfunc = (FP_SetVar)PatchList[GID_SETVAR].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    char varstr[MAX_STR_LEN+1];
    int vlen;
    ULONG optid;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, buffer, size, flags, libbase);
        if (result)
            return (result);
    }
    /*
     *        Now determine our flags. We recognise global, local
     *        or alias variables.
     */
    if        (flags & GVF_GLOBAL_ONLY)    optid = MSG_OPT_GLOBAL;
    else if ((flags & 7) == LV_VAR)        optid = MSG_OPT_LOCAL;
    else if ((flags & 7) == LV_ALIAS)    optid = MSG_OPT_ALIAS;
    else                                optid = MSG_OPT_UNKNOWN;

    /*
     *        Now create a string that looks like "Variable=Value"
     *
     *        We go to some pains to ensure we don't overwrite our
     *        string length
     */
    vlen = strlen(name);
    if (vlen > (MAX_STR_LEN-1)) {
        strncpy(varstr, name, MAX_STR_LEN);
        varstr[MAX_STR_LEN] = 0;
    } else {
        strcpy(varstr, name);
        strcat(varstr, "=");
        vlen = 98 - vlen;
        if (size != -1)
            vlen = MIN(vlen, size);

        strncat(varstr, buffer, vlen);
        varstr[MAX_STR_LEN] = 0;
    }

    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_SETVAR,
                     varstr, MSG(optid), NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, buffer, size, flags, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_DeleteVar()
 *
 *        Deletes an environment variable from the environment
 */
ULONG ASM New_DeleteVar(reg_d1 char *name, reg_d2 ULONG flags,
                         reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_DeleteVar origfunc = (FP_DeleteVar)PatchList[GID_SETVAR2].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    ULONG optid;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, flags, libbase);
        if (result)
            return (result);
    }
    /*
     *        Now determine our flags. We recognise global, local
     *        or alias variables.
     */
    if        (flags & GVF_GLOBAL_ONLY)    optid = MSG_OPT_GLOBAL;
    else if ((flags & 7) == LV_VAR)        optid = MSG_OPT_LOCAL;
    else if ((flags & 7) == LV_ALIAS)    optid = MSG_OPT_ALIAS;
    else                                optid = MSG_OPT_UNKNOWN;

    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_KILLVAR,
                     name, MSG(optid), NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, flags, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_LoadSeg()
 *
 *        Tries to load in a module from disk
 */
ULONG ASM New_LoadSeg(reg_d1 char *name, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_LoadSeg origfunc = (FP_LoadSeg)PatchList[GID_LOADSEG].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_LOADSEG,
                     name, NULL, EXPAND_NAME);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);

#if MONITOR_SEMAPHORE
        LoadTask = SysBase->ThisTask;
        result = origfunc(name, libbase);
        LoadTask = 0;
#else
        result = origfunc(name, libbase);
#endif
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_NewLoadSeg()
 *
 *        Tries to load in a module from disk
 */
ULONG ASM New_NewLoadSeg(reg_d1 char *name, reg_d2 TAGPTR tags,
                         reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_NewLoadSeg origfunc = (FP_NewLoadSeg)PatchList[GID_LOADSEG2].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, tags, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_NEWLOADSEG,
                     name, NULL, EXPAND_NAME);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, tags, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_NewLoadSeg()
 *
 *        Tries to load in a module from disk
 */
ULONG ASM New_Lock(reg_d1 char *name, reg_d2 LONG mode, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_Lock origfunc = (FP_Lock)PatchList[GID_LOCKFILE].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    LONG optid;
    char *curname;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, mode, libbase);
        if (result)
            return (result);
    }
    if        (mode == ACCESS_READ)        optid = MSG_OPT_READ;
    else if (mode == ACCESS_WRITE)        optid = MSG_OPT_WRITE;
    else                                optid = MSG_OPT_READBAD;

    curname = name;
    if (!ShowPaths && *curname == '\0')
        curname = "\"\"";

    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_LOCK,
                     curname, MSG(optid), EXPAND_NAME);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, mode, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_CreateDir()
 *
 *        Creates a new directory on disk
 */
ULONG ASM New_CreateDir(reg_d1 char *name, reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_CreateDir origfunc = (FP_CreateDir)PatchList[GID_MAKEDIR].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(name, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_MAKEDIR,
                     name, NULL, EXPAND_NAME);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_MakeLink()
 *
 *        Creates a new hard or soft link
 */
ULONG ASM New_MakeLink(reg_d1 char *name, reg_d2 LONG dest, reg_d3 LONG soft,
                        reg_a6 void *libbase)
{
    MarkCallAddr;
    struct Process *myproc = (struct Process *)SysBase->ThisTask;
    FP_MakeLink origfunc   = (FP_MakeLink)PatchList[GID_MAKELINK].origfunc;
    int onlyfails          = OnlyShowFails;
    Event *ev;
    ULONG result;
    LONG optid;
    char namestr[MAX_STR_LEN+1];
    LONG seqnum;
    int  len;

    if (onlyfails) {
        result = origfunc(name, dest, soft, libbase);
        if (result)
            return (result);
    }
    if (soft)    optid = MSG_OPT_SOFTLINK;
    else        optid = MSG_OPT_HARDLINK;

    /*
     *        Now build a string that looks like "name --> <dest>" to display
     *        as our link. For soft links, we just concatenate the two
     *        strings. For hard links, we have to generate a filename
     *        from the lock also.
     */
    len = strlen(name);
    if (len >= MAX_STR_LEN) {
        strncpy(namestr, name, MAX_STR_LEN);
        namestr[MAX_STR_LEN] = 0;
    } else {
        if (ShowPaths) {
            strcpy(namestr, MyNameFromLock(myproc->pr_CurrentDir,
                                           name, namestr, MAX_STR_LEN-2));
            len = strlen(namestr);
        } else
            strcpy(namestr, name);

        strcat(namestr, LinkPointerString);        /* Usually ' --> ' */
        if (soft) {
            strncat(namestr, (char *)dest, MAX_STR_LEN - len - 1);
            namestr[MAX_STR_LEN] = 0;
        } else {
            strcat(namestr, MyNameFromLock(dest, NULL, namestr+len+1,
                                                 MAX_STR_LEN-len-1));
        }
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_MAKELINK,
                     namestr, MSG(optid), NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, dest, soft, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_Open()
 *
 *        Opens a new file on disk
 */
ULONG ASM New_Open(reg_d1 char *name, reg_d2 LONG accessMode,
                  reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_Open origfunc = (FP_Open)PatchList[GID_OPENFILE].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    char *optstr;
    LONG  seqnum;

    if        (accessMode == MODE_OLDFILE)    optstr = MSG(MSG_OPT_READ);
    else if (accessMode == MODE_NEWFILE)    optstr = MSG(MSG_OPT_WRITE);
    else if (accessMode == MODE_READWRITE)    optstr = MSG(MSG_OPT_MODIFY);
    else                                    optstr = MSG(MSG_OPT_UNKNOWN);

    if (onlyfails) {
        result = origfunc(name, accessMode, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_OPEN,
                     name, optstr, EXPAND_NAME);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(name, accessMode, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_Rename()
 *
 *        Renames a file on disk. This is a little tricky, since we have
 *        to generate two events: one containing the source name and
 *        one containing the destination name.
 */
ULONG ASM New_Rename(reg_d1 char *oldname, reg_d2 char *newname,
                     reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_Rename origfunc = (FP_Rename)PatchList[GID_RENAME].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    LONG  seqnum;

    if (onlyfails) {
        result = origfunc(oldname, newname, libbase);
        if (result)
            return (result);
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_RENAME,
                     oldname, NULL, EXPAND_NAME);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }
    ev->status = ES_READY;
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_RENAME2,
                     newname, NULL, EXPAND_NAME);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(oldname, newname, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result)
            ev->result = MSG(MSG_RES_OKAY);
        else
            ev->result = MSG(MSG_RES_FAIL);
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_RunCommand()
 *
 *        Runs a command from disk. Like Execute() only with more control.
 */
ULONG ASM New_RunCommand(reg_d1 BPTR seglist,  reg_d2 ULONG stack,
                         reg_d3 char *cmdline, reg_d4 cmdlen,
                          reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_RunCommand origfunc = (FP_RunCommand)PatchList[GID_RUNCOMMAND].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    char  stacksize[40];    /* Reserve additional space for return code! */
    LONG  seqnum;
    int      stklen;
    char  *p;

    /*
     *        For functions that may potentially take a long time to complete,
     *        we check if they're being called from ROM straight away, so
     *        that we can exit and not hang around waiting for them if they
     *        are, even in the OnlyShowFails case.
     */
    if (!MonROMCalls && CallAddr >= RomStart && CallAddr <= RomEnd)
        JumpOrigFunc(0);

    if (onlyfails) {
        result = origfunc(seglist, stack, cmdline, cmdlen, libbase);
        if (result != -1)
            return (result);
    }

    /*
     *        This is kind of nasty but it works. We need somewhere to store
     *        the return code string, but when we call CreateEvent(), we
     *        don't know what it will be yet. So, we allocate additional
     *        space at the end of our stacksize to hold this info, and
     *        overwrite it later on.
     */
    mysprintf(stacksize, "%ld", stack);
    stklen = strlen(stacksize);
    strcat(stacksize, "................");    /* Storage for return code */

    /*
     *        Next, a quick hack to get rid of that nasty CR at the end
     *        of the string (purely for visual purposes -- we put it back
     *        afterwards, of course!)
     */
    for (p = cmdline; *p; p++) {
        if (*p == '\n') {
            *p = ' ';
            break;
        }
    }
    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_RUNCOMMAND,
                     cmdline, stacksize, NO_EXPAND);
    if (*p)
        *p = '\n';

    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }
    ev->options[stklen] = 0;

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->result = "----";
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(seglist, stack, cmdline, cmdlen, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result != -1) {
            ev->result = ev->options + stklen + 1;
            mysprintf(ev->result, "%ld", result);
        } else {
            ev->result = MSG(MSG_RES_FAIL);
        }
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*
 *        New_SystemTagList()
 *
 *        Executes a command line. Like Execute() only more powerful.
 */
ULONG ASM New_SystemTagList(reg_d1 char *cmdline, reg_d2 TAGPTR tags,
                             reg_a6 void *libbase)
{
    MarkCallAddr;
    FP_SystemTagList origfunc = (FP_SystemTagList)
                                 PatchList[GID_SYSTEM].origfunc;
    int onlyfails = OnlyShowFails;
    Event *ev;
    ULONG result;
    char  optstr[20];    /* Reserve additional space for return code! */
    LONG  seqnum;

    /*
     *        For functions that may potentially take a long time to complete,
     *        we check if they're being called from ROM straight away, so
     *        that we can exit and not hang around waiting for them if they
     *        are, even in the OnlyShowFails case.
     */
    if (!MonROMCalls && CallAddr >= RomStart && CallAddr <= RomEnd)
        JumpOrigFunc(0);

    if (onlyfails) {
        result = origfunc(cmdline, tags, libbase);
        if (result != -1)
            return (result);
    }
    /*
     *        This is kind of nasty but it works. We need somewhere to store
     *        the return code string, but when we call CreateEvent(), we
     *        don't know what it will be yet. So, we allocate space for our
     *        option string instead and then replace it with our result
     *        string later on.
     */
    strcpy(optstr, "............");    /* Storage for result string */

    ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_SYSTEM, cmdline,
                     optstr, NO_EXPAND);
    if (!ev) {
        if (onlyfails)
            return (result);
        JumpOrigFunc(0);
    }
    *ev->options = '\0';

    /*
     *        Allocated event safely, now tell SnoopDos task to wake up
     */
    if (onlyfails) {
        CheckForPause(NULL, 0);
    } else {
        ev->result = "----";
        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
        result = origfunc(cmdline, tags, libbase);
    }
    ObtainSemaphore(&BufSem);
    if (seqnum >= RealFirstSeq) {
        if (result != -1) {
            ev->result  = ev->options;
            ev->options = "";
            mysprintf(ev->result, "%ld", result);
        } else {
            ev->result = MSG(MSG_RES_FAIL);
        }
        ev->status = ES_READY;
        Signal(SnoopTask, NewEventMask);
    }
    ReleaseSemaphore(&BufSem);
    return (result);
}

/*****************************************************************************
 *
 *      Now the Mother of all patches -- the PutMsg() packet monitor/Rexx patch
 *
 *      (There are quite a few sub-functions associated with this.)
 *
 *****************************************************************************/

/*
 *        New_AddDosEntry(dlist)
 *
 *        This is a very simple patch which is only enabled when we are
 *        monitoring DOS packets. It simply signals the main task to update
 *        the device list whenever a new device is added to the DOS device
 *        list.
 */
ULONG ASM New_AddDosEntry(reg_d1 struct DosList *dlist, reg_a6 void *libbase)
{
    FP_AddDosEntry origfunc = (FP_AddDosEntry)
                               PatchList[GID_ADDDOSENTRY].origfunc;
    ULONG result;

    /*
     *        Note that we better remember to actually add the new device
     *        before telling SnoopDos to update its list, otherwise it
     *        might miss it if it's too quick (e.g. priority > 0).
     *
     *        New: Even though we DO add it before signalling SnoopDos, the
     *        device itself won't be fully initialised for a little bit longer.
     *        Therefore, the main SnoopDos code
     */
    result = origfunc(dlist, libbase);

    if (dlist && dlist->dol_Type == DLT_DEVICE)
        Signal(SnoopTask, ScanDosListMask);

    return (result);
}

/*
 *        AddWaitingPacket(ev, seqnum, failmsg, dp, port, pt)
 *
 *        Adds a new entry to the list of waiting packets containing enough
 *        information to allow us to identify the reply to the packet when
 *        it is processed later on (in the main PutMsg() patch).
 *
 *        If there isn't a spare waiting packet, we will steal one and mark
 *        the event it represented as "Miss" to indicate the return code
 *        was missed.
 */
void AddWaitingPacket(Event *ev, LONG seqnum, char *failmsg,
                      struct DosPacket *dp, struct MsgPort *port,
                      struct PacketRef *pt)
{
    WaitPacket *wp;
    Event *oldev;
    ULONG oldseq;

    /*
     *        Add details about this packet to our list of waiting
     *        packets, so that when we spot the packet being returned
     *        by PutMsg() later on, we can fill in the result code.
     *
     *        Note that we must not obtain both the buffer and packet
     *        semaphores simultaneously, or a deadlock could occur.
     */
    ObtainSemaphore(&PacketSem);
    if (IsListEmpty(&PacketFreeList)) {
        /*
         *        Removing an existing node which is already in use. We need
         *        to signal our main task to tell it not to continue waiting
         *        for this event to complete. We have to wait until we unlock
         *        the packetsem so we just note the details for now.
         */
        wp     = (WaitPacket *)RemTail(&PacketWaitList);
        oldseq = wp->eventnum;
        oldev  = wp->event;
        //    if (!wp)
        //        KPrintF("Warning!! No packet available on WaitList!\n");
    } else {
        wp     = (WaitPacket *)RemHead(&PacketFreeList);
        oldseq = 0;
    }
    wp->dp        = dp;
    wp->sendtask = SysBase->ThisTask;
    wp->destport = port;
    wp->event    = ev;
    wp->eventnum = seqnum;
    wp->arg1      = dp->dp_Arg1;
    wp->arg2      = dp->dp_Arg2;
    wp->arg3      = dp->dp_Arg3;
    wp->resmsg     = failmsg;
    wp->flags    = pt->flags;
    AddHead(&PacketWaitList, (Node *)wp);
    ReleaseSemaphore(&PacketSem);

    /*
     *        Finally, check if we had to flush out an old packet from
     *        our list of waiting packets when we allocated the new
     *        packet. If so, mark the packet as missed (if it hasn't
     *        already scrolled off the top of the buffer)
     */
    if (oldseq) {
        ObtainSemaphore(&BufSem);
        if (oldseq >= RealFirstSeq) {
            oldev->result = MSG(MSG_RES_MISSED);
            oldev->status = ES_READY;
            Signal(SnoopTask, NewEventMask);
        }
        ReleaseSemaphore(&BufSem);
    }
}

/*
 *        HandleSimplePacket(calladdr, packet, port, packetref)
 *
 *        Handles the given packet by creating an event that matches the
 *        packet type (if we support it) and creating a new entry on the
 *        waiting packet list so we can match it up later.
 *
 *        This function handles only simple packets (i.e. those with the
 *        PK_COMMON flag set in the packet table). If the corresponding
 *        AmigaDOS option (Open, Lock, MakeDir etc.) is not currently
 *        enabled, then no entry is made for this packet.
 */
void HandleSimplePacket(ULONG calladdr, struct DosPacket *dp,
                         struct MsgPort *port, struct PacketRef *pt)
{
    /*
     *        Now create our new simple event to represent the packet.
     *        The contents of this will vary depending on the packet
     *        itself, but in general, is an exact match with the format
     *        of the AmigaDOS function associated with the packet.
     *
     *        (If that function is not being monitored, then we do nothing.)
     */
    Event *ev;
    LONG  seqnum;
    ULONG gadid;
    ULONG actid = 0;
    char  *volname = ((Task *)(port->mp_SigTask))->tc_Node.ln_Name;
    BPTR  lock = NULL;
    BSTR  name;
    char  *optstr;
    char  namebuf[MAX_STR_LEN+1];
    char  optbuf[20];

    namebuf[0] = '\0';

    /*
     *        First, determine the format to use, based on the packet type
     */
    switch (dp->dp_Type) {
        case ACTION_FINDINPUT:
            gadid    = GID_OPENFILE;
            actid    = MSG_ACT_POPEN;
            lock    = dp->dp_Arg2;
            name    = dp->dp_Arg3;
            optstr    = MSG(MSG_OPT_READ);
            break;

        case ACTION_FINDOUTPUT:
            gadid    = GID_OPENFILE;
            actid    = MSG_ACT_POPEN;
            lock    = dp->dp_Arg2;
            name    = dp->dp_Arg3;
            optstr    = MSG(MSG_OPT_WRITE);
            break;

        case ACTION_FINDUPDATE:
            gadid    = GID_OPENFILE;
            actid    = MSG_ACT_POPEN;
            lock    = dp->dp_Arg2;
            name    = dp->dp_Arg3;
            optstr    = MSG(MSG_OPT_MODIFY);
            break;

        case ACTION_DELETE_OBJECT:
            gadid    = GID_DELETE;
            actid    = MSG_ACT_PDELETE;
            lock    = dp->dp_Arg1;
            name    = dp->dp_Arg2;
            optstr  = NULL;
            break;

        case ACTION_CREATE_DIR:
            gadid    = GID_MAKEDIR;
            actid    = MSG_ACT_PMAKEDIR;
            lock    = dp->dp_Arg1;
            name    = dp->dp_Arg2;
            optstr  = NULL;
            break;

        case ACTION_LOCATE_OBJECT:
            gadid    = GID_LOCKFILE;
            actid    = MSG_ACT_PLOCK;
            lock    = dp->dp_Arg1;
            name    = dp->dp_Arg2;
            switch (dp->dp_Arg3) {
                case ACCESS_READ:    optstr = MSG(MSG_OPT_READ);        break;
                case ACCESS_WRITE:    optstr = MSG(MSG_OPT_WRITE);    break;
                default:            optstr = MSG(MSG_OPT_READBAD);    break;
            }
            break;

        case ACTION_MAKE_LINK:
        {
            int len;
            char *cname;

            gadid    = GID_MAKELINK;
            actid    = MSG_ACT_PMAKELINK;
            lock    = dp->dp_Arg1;
            cname    = BTOC(dp->dp_Arg2);

            /*
             *        Now build a string that looks like "name --> <dest>" to
             *        display as our link. For soft links, we just concatenate
             *        the two strings. For hard links, we have to generate a
             *        filename from the lock also.
             */
            len = *cname;
            if (len >= MAX_STR_LEN) {
                strncpy(namebuf, cname+1, MAX_STR_LEN);
                namebuf[MAX_STR_LEN] = 0;
            } else {
                if (ShowPaths) {
                    char *tempbuf = namebuf + MAX_STR_LEN-9 - len;

                    memcpy(tempbuf, cname+1, len);
                    tempbuf[len] = '\0';
                    strcpy(namebuf, AsyncNameFromLock(volname, lock, tempbuf,
                                                      namebuf, MAX_STR_LEN-8));
                    len = strlen(namebuf);
                } else {
                    memcpy(namebuf, cname+1, len);
                    namebuf[len] = '\0';
                }
                strcat(namebuf, LinkPointerString);        /* Usually ' --> ' */
                len += strlen(LinkPointerString);

                if (dp->dp_Arg4 == LINK_HARD) {
                    /*
                     *        Hard link: interpret dp->dp_Arg3 as the lock
                     *        being linked to
                     */
                    strcat(namebuf, AsyncNameFromLock(volname, dp->dp_Arg3,
                                                      NULL, namebuf+len+1,
                                                      MAX_STR_LEN-len-1));
                    optstr = MSG(MSG_OPT_HARDLINK);
                } else {
                    /*
                     *        Soft link: interpret dp->dp_Arg3 as the name of
                     *        the path to the link
                     */
                    strncat(namebuf, (char *)dp->dp_Arg3, MAX_STR_LEN-len-1);
                    namebuf[MAX_STR_LEN] = 0;
                    optstr = MSG(MSG_OPT_SOFTLINK);
                }
            }
            volname = (char *)NO_EXPAND; /* Don't try and expand filename */
            name    = NULL;
            break;
        }

        case ACTION_RENAME_OBJECT:
            lock    = dp->dp_Arg1;
            name    = dp->dp_Arg2;
            optstr    = NULL;

            /*
             *        This is a bit cheeky. The Rename action comes in
             *        two parts, the first line with the original name and
             *        the second part with the new name. We create the
             *        first part here, and then fall through to let the
             *        rest of the code handle the second part.
             */
            if (CurSettings.Func.Opts[GID_RENAME]) {
                char *cname = BTOC(name);

                lock          = dp->dp_Arg3;
                name          = dp->dp_Arg4;
                if (*cname) {
                    memcpy(namebuf, cname+1, *cname);
                    namebuf[*cname] = '\0';
                } else {
                    /*
                     *        If we have an empty string, we replace it with ""
                     *        since we may be renaming the current directory (?)
                     */
                    strcpy(namebuf, "\"\"");
                }
                ev = CreateEvent(calladdr, &seqnum, MSG_ACT_PRENAME,
                                 namebuf, NULL, (int)volname, lock);
                if (!ev)
                    return;

                ev->status    = ES_READY;
                gadid        = GID_RENAME;
                actid         = MSG_ACT_PRENAME2;
            }
            break;
    }

    /*
     *        Now, if we recognised the packet type, create a new event
     *        with the info stored accordingly. We ignore any packets
     *        for which monitoring is disabled.
     */
    if (actid && CurSettings.Func.Opts[gadid]) {
        /*
         *        We reserve 8 bytes at the start of the options string to
         *        hold the result message (Ok or Fail) that is filled in
         *        by the PutMsg() code when the packet is returned.
         */
#define RES_LEN        8

        strcpy(optbuf, "........");
        if (optstr)
            strcat(optbuf, optstr);

        if (name) {
            char *cname = BTOC(name);

            namebuf[0] = '\0';
            if (*cname) {
                memcpy(namebuf, cname+1, *cname);
                namebuf[*cname] = '\0';
            } else {
                /*
                 *        If we have an empty string, we replace it with ""
                 *        since it will typically be a Lock("").
                 */
                strcpy(namebuf, "\"\"");
            }
        }
        ev = CreateEvent(calladdr, &seqnum, actid, namebuf, optbuf,
                         (int)volname, lock);
        if (!ev)
            return;

        ev->result    = ev->options;
        ev->options  += RES_LEN;
        *ev->result   = '\0';
        ev->status    = ES_UPDATING;
        /*
         *        We add the event to the waiting list BEFORE checking for Pause
         *        so that if while paused, the user decides to disable packet
         *        monitoring, the packet will be in the wait queue already and
         *        thus will be safely flushed; otherwise, it would hang around
         *        for ever (not doing any damage but wasting resources).
         */
        AddWaitingPacket(ev, seqnum, "%s", dp, port, pt);
        CheckForPause(ev, seqnum);
        Signal(SnoopTask, NewEventMask);
    }
#undef RES_LEN
}

/*
 *        HandleRawPacket(calladdr, packet, port, packetref)
 *
 *        Handles the given packet by creating an event that matches the
 *        packet type (if we support it) and creating a new entry on the
 *        waiting packet list so we can match it up later.
 *
 *        This function handles all packets and produces a raw hex dump
 *        (with the name of the packet) rather than the more english-like
 *        "Open", "Lock", etc.
 */
void HandleRawPacket(ULONG calladdr, struct DosPacket *dp,
                     struct MsgPort *port, struct PacketRef *pt)
{
    /*
     *        Building this event is a little tricky, since the result
     *        string will not be a static string but will contain the
     *        actual return value. Thus, we allocate enough room in the
     *        filename portion to hold the result string as well, and
     *        adjust our variables accordingly after the event has
     *        been created.
     *
     *        The same is true for raw packet types (i.e. those that we
     *        don't recognise at all).
     */
#define RAW_LEN        20        /* Length of possible raw packet type    */
#define RES_LEN        26        /* Length of longest result code        */
#define ARG_LEN        50        /* Length of longest argument list        */

    static char *fmt[] = {
        "(None)", "%8lx", "%8lx, %8lx", "%8lx, %8lx, %8lx",
        "%8lx, %8lx, %8lx, %8lx", "%8lx, %8lx, %8lx, %8lx, %8lx"
    };
    static char *failmsg[] = {
        "%s", "%-4s %8lx", "%-4s %8lx", "%-4s %8lx, %8lx"
    };
    char args[RAW_LEN+RES_LEN+ARG_LEN];
    char *tname = args;
    Event *ev;
    LONG  seqnum;

    if (pt->flags & PK_RAW)
        tname += RAW_LEN;

    tname += RES_LEN;
    memset(args, ' ', tname - args);
    mysprintf(tname, fmt[pt->numparams], dp->dp_Arg1, dp->dp_Arg2,
                            dp->dp_Arg3, dp->dp_Arg4, dp->dp_Arg5);

    ev = CreateEvent(calladdr, &seqnum, pt->msgid, args,
                     ((Task *)(port->mp_SigTask))->tc_Node.ln_Name,
                     NO_EXPAND);
    if (!ev)
        return;

    if (pt->flags & PK_RAW) {
        /*
         *        Now fix up action name and target name
         */
        ev->action    = ev->filename;
        ev->filename += RAW_LEN;
        mysprintf(ev->action, MSG(MSG_ACT_RAWPACKET), dp->dp_Type);
    }
    ev->result    = ev->filename;    /* Point to storage for later result */
    ev->filename += RES_LEN;
    *ev->result   = 0;                /* Make result field empty initially */
    ev->status      = ES_UPDATING;
    /*
     *        We add the event to the waiting list BEFORE checking for Pause
     *        so that if while paused, the user decides to disable packet
     *        monitoring, the packet will be in the wait queue already and
     *        thus will be safely flushed; otherwise, it would hang around
     *        for ever (not doing any damage but wasting resources).
     */
    AddWaitingPacket(ev, seqnum, failmsg[pt->flags & PK_MASK], dp, port, pt);
    CheckForPause(ev, seqnum);
    Signal(SnoopTask, NewEventMask);
}

/*
 *        New_PutMsg()
 *
 *        This function is used frequently by the system to send a message
 *        from one task to another. It is also used by applications wishing
 *        to send ARexx messages, which is what we want to monitor.
 *
 *        The problem is: how do we distinguish system messages (of which
 *        there are lots!) from ARexx messages (which are relatively
 *        infrequent).
 *
 *        It's almost impossible to get a perfect solution to this, but we
 *        can get fairly close by checking the following:
 *
 *          - The destination port must have a name
 *          - The host name associated with the supposed Rexx message must
 *            point to valid memory
 *        - The action type for the Rexx message is RXCOMM
 *        - The Rexx system library must be up and running
 *        - The library base must be word aligned (else we fault on a 68000)
 *        - The Close() vector in the Rexx private system library must
 *            match the Close() vector in the Rexx library base that we
 *            opened ourselves (the library bases themselves can be different).
 *
 *        If all these hold true, then we can assume it is a valid ARexx
 *        message and display it accordingly.
 *
 *        For DOS packets, things are a little simpler since DOS packets contain
 *        cross-links that can be easily checked for validity. To keep things
 *        moving at a reasonable speed, we only consider StandardPackets, where
 *        the DosPacket structure immediately follows the exec message structure.
 *        This is not universally true, but it covers all the cases we want to
 *        monitor.
 *
 *        We need to intercept DOS packets twice -- once on the initial PutMsg
 *        to the target device, and once when the target device PutMsg's the
 *        reply. Thus, we maintain a list of outstanding packets so we can
 *        detect which is which.
 *
 *        To identify DOS packets, we use the following criterion:
 *
 *            - Task is a process
 *            - Message node's name points to valid longword-aligned memory
 *            - DOS packet (from name ptr) points back to message header
 *            - Either current task is on the list of devices we're monitoring
 *              or the destination message port's owner is on the list of
 *              devices we're monitoring.
 *
 *        If any of these conditions fail, we ignore the message.
 *
 */
ULONG ASM New_PutMsg(reg_a0 struct MsgPort *port, reg_a1 struct Message *msg,
                     reg_a6 void *libbase)
{
    MarkCallAddr;

    FP_PutMsg origfunc   = (FP_PutMsg)PatchList[GID_SENDREXX].origfunc;
    Task *thistask         = SysBase->ThisTask;

/*
 *        Save a little stack space and time by making these non-local
 */
#define rmsg            ((struct RexxMsg *)msg)
#define rexxclosevect     (ULONG *)(((ULONG)RexxSysBase) - 10)
#define thisclosevect    (ULONG *)(((ULONG)rmsg->rm_LibBase) - 10)

    struct DosPacket *dp;
    Task  *desttask;
    Event *ev;
    LONG  seqnum;
    ULONG taskhandle;

    /*
     *        Before doing anything else, check if we're being called from
     *        within an interrupt. If so, get the heck out of here since
     *        trying to obtain a semaphore from within an interrupt is
     *        definitely a bad idea!
     *
     *        To quickly check if we're within an interrupt, we simply see
     *        if our stack pointer is within the range of the supervisor stack.
     *        If it is, then we're probably in an interrupt, or at least in
     *        Supervisor mode, and either way we don't want to continue.
     *
     *        We also ignore ramlib, for the usual reasons, and our own
     *        background task (since it is used to expand locks from within
     *        of this patch and an infinite loop would be easy!)
     */
    if (thistask == RamLibTask || thistask == (Task *)BackgroundProc ||
        (getreg(REG_A7) >= (ULONG)SysBase->SysStkLower &&
         getreg(REG_A7) <= (ULONG)SysBase->SysStkUpper))
    {
        JumpOrigFunc(0);
    }

    /*
     *        See if we have a valid ARexx message. See the function
     *        header for an explanation of all the checks
     */
    if (CurSettings.Func.Opts[GID_SENDREXX]            &&
        port->mp_Node.ln_Name                        &&
        *port->mp_Node.ln_Name                        &&
        rmsg->rm_CommAddr                            &&
        TypeOfMem(rmsg->rm_CommAddr)                &&
        (rmsg->rm_Action & RXCODEMASK) == RXCOMM    &&
        RexxSysBase                                    &&
        TypeOfMem(thisclosevect)                    &&
        ((ULONG)thisclosevect & 1) == 0             &&
        *thisclosevect == *rexxclosevect)
    {
        /*
         *        Okay, we know we've got a valid Rexx message so now enter
         *        it into the event buffer. First, however, check that we
         *        are within our stack bounds (since the normal check done
         *        in the assembly patch code is bypassed for this function
         *        to accomodate RAM returning DOS packets).
         */
        if (getreg(REG_A7) >= (ULONG)thistask->tc_SPLower &&
             getreg(REG_A7) <= (ULONG)thistask->tc_SPUpper &&
             getreg(REG_A7) <=
                         ((ULONG)thistask->tc_SPLower+CurSettings.StackLimit))
        {
            JumpOrigFunc(0);
        }
        ev = CreateEvent(CallAddr, &seqnum, MSG_ACT_SENDREXX, rmsg->rm_Args[0],
                         port->mp_Node.ln_Name, NO_EXPAND);
        if (!ev)
            return origfunc(port, msg, libbase);

        ev->status = ES_UPDATING;
        CheckForPause(ev, seqnum);
        ObtainSemaphore(&BufSem);
        if (seqnum >= RealFirstSeq) {
            ev->status = ES_READY;
            Signal(SnoopTask, NewEventMask);
        }
        ReleaseSemaphore(&BufSem);
        return origfunc(port, msg, libbase);
    }

    /*
     *        Not an ARexx message, now check if it's a DOS packet.
     *        First though, we must check to see if we're already in
     *        the middle of a SnoopDos patch -- if so, we could end up
     *        recursing forever unless we don't try and monitor this one.
     *
     *        See above for the criteria we use to spot packet messages.
     */
    taskhandle = CheckTaskRecursion();
    if (!taskhandle)
        return origfunc(port, msg, libbase);

    dp         = (struct DosPacket *)(msg->mn_Node.ln_Name);
    desttask = port->mp_SigTask;

    if ((ShowAllPackets | MonPackets)                            &&
        thistask->tc_Node.ln_Type == NT_PROCESS                    &&
        ((ULONG)dp & 1) == 0                                    &&
        TypeOfMem(dp)                                            &&
        dp->dp_Link == msg                                        &&
        ((ULONG)(dp->dp_Port) & 3) == 0                            &&
        TypeOfMem(dp->dp_Port))
    {
        /*
         *        Looks like we're going to monitor the packet.
         *
         *        First, check if the packet is already on our list of
         *        outstanding packets. If so, we can handle it immediately.
         */
        struct PacketRef *pt;
        WaitPacket *wp;
        Task **ptask;
        char *p = NULL;

        /*
         *        Now some slightly tricky stuff. We can have up to TWO
         *        entries on the waiting packet list which match the current
         *        packet (one for the Packet Debugger and one for the
         *        Monitor Packets option) and we need to acknowledge them
         *        both. However, we also need to ensure we never try and
         *        lock both the PacketSem and BufferSem at the same time
         *        (since otherwise we could deadlock).
         *
         *        This effectively means we have to restart our list scan
         *        after each packet has been acknowledged, until we have
         *        no more left -- a small speed hit, but actually not too
         *        bad since most times, we will be the only packet on the
         *        wait list anyway. (We use 'p' as a flag to indicate
         *        whether or not we found a packet, so we know to return
         *        at the end of it all.)
         */
        ObtainSemaphore(&PacketSem);
        wp = HeadNode(&PacketWaitList);
        while (NextNode(wp)) {
            if (wp->dp         == dp                    &&
                wp->sendtask != thistask            &&
                wp->destport != port                &&
                wp->arg1     == dp->dp_Arg1            &&
                wp->arg2     == dp->dp_Arg2            &&
                wp->arg3     == dp->dp_Arg3)
            {
                /*
                 *        Found the packet on our list, so go ahead and fill in
                 *        the result code for the associated event (assuming it
                 *        hasn't scrolled off the buffer, of course!)
                 */
                Event *ev       = wp->event;
                LONG   seqnum = wp->eventnum;
                char  *fmsg   = wp->resmsg;
                char   flags  = wp->flags;

                Remove((Node *)wp);
                AddHead(&PacketFreeList, (Node *)wp);
                ReleaseSemaphore(&PacketSem);
                ObtainSemaphore(&BufSem);
                if (seqnum >= RealFirstSeq) {
                    /*
                     *        Okay, now fill in the result string. The space for
                     *        this was allocated when the event was defined.
                     *
                     *        For events that succeed, we can print "Okay",
                     *        "Okay <result>", and "Okay <result1> <result2>".
                     *
                     *        For events which fail, we can print
                     *        "Fail <result2>" or "Fail <result1> <result2>"
                     */
                    UWORD fail;
                    ULONG param;
                    char  *q, *r;

#define                      evresmsg    MSG(fail ? MSG_RES_FAIL : MSG_RES_OKAY)

                     fail = ((flags & PKF_BOOL) && dp->dp_Res1 == 0)     ||
                           ((flags & PKF_NEG)  && dp->dp_Res1 == (ULONG)-1);

#if NOT_WORRIED_ABOUT_STACK_SIZE
                    /*
                     *        Unfortunately, we can't use this nice simple
                     *        code because calling mysprintf() uses too much
                     *        stack space if we're being called from certain
                     *        handlers with minimal stack space (e.g. RAM).
                     *        Instead, we must do the same effect ourselves.
                     *        This code is left here so you can see what the
                     *        original intention was.
                     */
                    if ((flags & PK_MASK) == PK_2OK) {
                        mysprintf(ev->result, fmsg, evresmsg,
                                  dp->dp_Res1, dp->dp_Res2);
                    } else {
                        mysprintf(ev->result, fmsg, evresmsg,
                                  (fail ? dp->dp_Res2 : dp->dp_Res1));
                    }
                    p = (char *)-1;    /* Non-zero means we did something */

#else /* Extremely worried about stack size */

                    /*
                     *        Here we roll our own sprintf() (inline!) to keep
                     *        stack usage to an absolute minimum. It's a rather
                     *        small subset and somewhat hacked, you'll notice.
                     *
                     *        We make P non-null to indicate we did some work
                     */
                    p = fmsg;
                    q = ev->result;

                    /*
                     *        First, skip over string formatter at start which
                     *        always holds either 'Ok' or 'Fail'
                     */
                    strcpy(q, evresmsg);
                    q += strlen(q);
                    while (q < (ev->result + 4))
                        *q++ = ' ';
                    while (*p && *p != 's')
                        p++;
                    if (*p)
                        p++;

                    /*
                     *        Now parse remainder of string. The first parameter
                     *        encountered gets replaced with either dp_Res1 or
                     *        dp_Res2, depending on circumstances. The second
                     *        parameter always gets replaced with dp_Res2.
                     */
                    if ((flags & PK_MASK) == PK_2OK || !fail)
                        param = dp->dp_Res1;
                    else
                        param = dp->dp_Res2;

                    while (*p) {
                        if (*p != '%') {
                            *q++ = *p++;
                            continue;
                        }
                        while (*p && *p != 'x' && *p != 'X')
                            p++;
                        p++;
                        if (param == 0) {
                            strcpy(q, "       0");
                        } else if (param == (ULONG)-1) {
                            strcpy(q, "      -1");
                        } else {
                            /*
                             *        Expand param to 8 hex digits, right-aligned
                             */
                            r = q + 7;
                            while (param > 0) {
                                *r-- = "0123456789ABCDEF"[param & 15];
                                param >>= 4;
                            }
                            while (r >= q)
                                *r-- = ' ';
                        }
                        q += 8;
                        param = dp->dp_Res2; /* Second parm always dp_Res2 */
                    }
                    *q = '\0';
#endif
                    /*
                     *        Unlike most times, we don't signal SnoopDos that
                     *        an event has been updated (yet) since there may
                     *        be another event to update too, and it's best
                     *        to do a single signal at the end (fewer context
                     *        switches are required.) So, we just mark the
                     *        event as ready.
                     */
                    ev->status = ES_READY;
                }
                ReleaseSemaphore(&BufSem);
                ObtainSemaphore(&PacketSem);
                /*
                 *        Now restart the search from the beginning of the
                 *        list (since wp is no longer valid)
                 */
                wp = HeadNode(&PacketWaitList);
            } else {
                /*
                 *        Just advance to next element on list
                 */
                wp = NextNode(wp);
            }
        }
        ReleaseSemaphore(&PacketSem);
        if (p) {
            /*
             *        Found a matching packet, so wake up the main task
             *        and finish up. (We only signal the main snoop task
             *        now, so that both events get printed simultaneously,
             *        rather than one after another, which would be a little
             *        messy). This also avoids us getting pre-empted inside
             *        our loop above if SnoopDos is running at a higher priority
             *        than this task, which is convenient (though not essential).
             */
            Signal(SnoopTask, NewEventMask);
            goto done_putmsg;
        }

        /*
         *        If we didn't find a match on our list of waiting packets,
         *        then check to see if we're ignoring ROM calls. If so,
         *        and if we were called from ROM, then immediately abort
         *        (this would be done later anyway, but by checking now,
         *        we save quite a bit of time.)
         *
         *        (We can't do this checking any earlier, or we'd miss
         *        returned packets from ROM filesystems like RAM: and FFS).
         *
         *        We also exit if we're under the stack limit. (We can't
         *        check this earlier because otherwise we'd miss the
         *        return packet from RAM which only has a tiny stack.)
         */
        if (((!MonROMCalls && CallAddr >= RomStart && CallAddr <= RomEnd)) ||
            (getreg(REG_A7) >= (ULONG)thistask->tc_SPLower &&
             getreg(REG_A7) <= (ULONG)thistask->tc_SPUpper &&
             getreg(REG_A7) <=
                         ((ULONG)thistask->tc_SPLower+CurSettings.StackLimit)))
        {
            goto done_putmsg;
        }

        /*
         *        Okay, didn't match the packet with a previous outgoing one.
         *        Now search the device list to see if we can match either
         *        the owner of the port (a new outgoing packet) or the task ID
         *        of the sender (a returning packet).
         *
         *        In the case of a returning packet, we just ignore it since
         *        we missed it on the way out.
         */
        for (ptask = DeviceTaskList; *ptask && *ptask != desttask; ptask++) {
            if (*ptask == thistask)
                goto done_putmsg;    /* Sender was a DOS device so ignore */
        }
        if (!*ptask) {
            /*
             *        Couldn't find dest task on device list so it must
             *        be a message to somewhere else -- hence, ignore it.
             */
            goto done_putmsg;
        }

        /*
         *        Okay, got ourselves a bona fida packet. Next, look it up
         *        in our packet table to decide what to do with it.
         *        Unrecognised packets come out as LAST_PACK_MSG which is
         *        specifically initialised to handle them properly.
         */
        for (pt = &PacketTable[0]; pt->msgid != LAST_PACK_MSG; pt++)
            if (pt->packetid == dp->dp_Type)
                break;

        if (pt->flags & PK_IGNORE)    /* Certain packet types are ignored */
            goto done_putmsg;

        /*
         *        Okay, we finally (finally!) get to create a new entry
         *        in our event buffer. Actually, we get to create two
         *        entries, since if we have both the Packet Debugger
         *        AND the Monitor Packets option turned on, we want to
         *        see the output from both of them (even if they're both
         *        the same event!).
         *
         *        Why? Well, if you're debugging a device driver and you
         *        have Open packets etc. coming back and forth, then
         *        as well as the raw packet data, it's also kind of nice
         *        to see actual filenames etc. in english instead of hex.
         */
        if (MonPackets && (pt->flags & PK_COMMON))
            HandleSimplePacket(CallAddr, dp, port, pt);

        if (ShowAllPackets)
            HandleRawPacket(CallAddr, dp, port, pt);
    }

done_putmsg:
    EndTaskRecursion(taskhandle);
    return origfunc(port, msg, libbase);
}