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BCHDRN.C
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1992-03-25
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/* -*- C -*-
$Header: /scheme/src/microcode/RCS/bchdrn.c,v 1.4 1992/03/26 04:21:11 cph Exp $
Copyright (c) 1991-92 Massachusetts Institute of Technology
This material was developed by the Scheme project at the Massachusetts
Institute of Technology, Department of Electrical Engineering and
Computer Science. Permission to copy this software, to redistribute
it, and to use it for any purpose is granted, subject to the following
restrictions and understandings.
1. Any copy made of this software must include this copyright notice
in full.
2. Users of this software agree to make their best efforts (a) to
return to the MIT Scheme project any improvements or extensions that
they make, so that these may be included in future releases; and (b)
to inform MIT of noteworthy uses of this software.
3. All materials developed as a consequence of the use of this
software shall duly acknowledge such use, in accordance with the usual
standards of acknowledging credit in academic research.
4. MIT has made no warrantee or representation that the operation of
this software will be error-free, and MIT is under no obligation to
provide any services, by way of maintenance, update, or otherwise.
5. In conjunction with products arising from the use of this material,
there shall be no use of the name of the Massachusetts Institute of
Technology nor of any adaptation thereof in any advertising,
promotional, or sales literature without prior written consent from
MIT in each case. */
/* Drone program for overlapped I/O in bchscheme. */
#include <setjmp.h>
#include "ux.h"
#include "bchdrn.h"
#define DEBUG
/* #define DEBUG_1 */
/* #define DEBUG_2 */
extern char * EXFUN (error_name, (int));
extern int EXFUN (retrying_file_operation,
(/* no prototype because (CONST char *) != (char *) */
int EXFUN((*), ()),
int, char *, long, long, char *, char *, long *,
int EXFUN((*), (char *, char *))));
#ifdef HAVE_SYSV_SHARED_MEMORY
static struct
{
char * program_name;
char * file_name; /* gc file name */
int shmid; /* shared memory descriptor */
int tdron; /* total number of drones */
int nbuf; /* total number of buffers */
long bufsiz; /* size of each buffer in bytes */
int sdron; /* index of first drone to start */
int ndron; /* number of drones to start */
int keep_p; /* keep the gc file if Scheme dies? */
} arguments;
struct argdesc
{
char * name;
char * format;
PTR location;
};
static char string_a[] = "%s";
#define STRING_FMT &string_a[0]
static char decimal_int_a[] = "%d";
#define DECIMAL_INT_FMT &decimal_int_a[0]
static char decimal_long_a[] = "%ld";
#define DECIMAL_LONG_FMT &decimal_long_a[0]
static struct argdesc command_line[] =
{
{ "program_name", STRING_FMT, &arguments.program_name },
{ "file_name", STRING_FMT, &arguments.file_name },
{ "shmid", DECIMAL_INT_FMT, &arguments.shmid },
{ "tdron", DECIMAL_INT_FMT, &arguments.tdron },
{ "nbuf", DECIMAL_INT_FMT, &arguments.nbuf },
{ "bufsiz", DECIMAL_LONG_FMT, &arguments.bufsiz },
{ "sdron", DECIMAL_INT_FMT, &arguments.sdron },
{ "ndron", DECIMAL_INT_FMT, &arguments.ndron },
{ "keep_gc_file", DECIMAL_INT_FMT, &arguments.keep_p }
};
static int gc_fid = -1;
static char * shared_memory;
static struct buffer_info * gc_buffers;
static struct drone_info * myself;
static unsigned long * drone_version, * wait_mask;
static jmp_buf abort_point;
static pid_t boss_pid;
static void
DEFUN (posix_signal, (signum, handler),
int signum AND void EXFUN ((*handler), ()))
{
static void EXFUN (shutdown, ());
struct sigaction new;
new.sa_handler = handler;
UX_sigemptyset (&new.sa_mask);
UX_sigaddset ((&new.sa_mask), SIGCONT);
UX_sigaddset ((&new.sa_mask), SIGQUIT);
new.sa_flags = SA_NOCLDSTOP;
if ((UX_sigaction (signum, &new, 0)) == -1)
{
fprintf (stderr, "%s (%d, posix_signal): sigaction failed. errno = %s.\n",
arguments.program_name, myself->index, (error_name (errno)));
fflush (stderr);
shutdown (0);
/*NOTREACHED*/
}
return;
}
static void
DEFUN (shutdown, (sig), int sig)
{
myself->state = drone_dead;
if (gc_fid != -1)
close (gc_fid);
shmdt (shared_memory);
if (sig == -1)
{
shmctl (arguments.shmid, IPC_RMID, ((struct shmid_ds *) 0));
if (!arguments.keep_p)
unlink (arguments.file_name);
}
exit (0);
/*NOTREACHED*/
}
static void
DEFUN (abort_operation, (sig), int sig)
{
RE_INSTALL_HANDLER (SIGQUIT, abort_operation);
myself->state = drone_aborting;
longjmp (abort_point, 1);
/*NOTREACHED*/
}
static void
DEFUN (continue_running, (sig), int sig)
{
RE_INSTALL_HANDLER (SIGCONT, continue_running);
longjmp (abort_point, 1);
/*NOTREACHED*/
}
static int
DEFUN (always_one, (operation_name, noise),
char * operation_name AND char * noise)
{
return (1);
}
static void
DEFUN (process_requests, (drone), struct drone_info * drone)
{
#if !(defined(_HPUX) && (_HPUX_VERSION >= 80))
extern int EXFUN (select, (int, int *, int *, int *, struct timeval *));
#endif
sigset_t non_blocking_signal_mask, blocking_signal_mask;
int result, count, buffer_index, flags;
long current_position = -1;
struct timeval timeout;
struct stat file_info;
unsigned long read_mask, my_mask;
myself = drone;
my_mask = (((unsigned long) 1) << drone->index);
drone->DRONE_PID = (getpid ());
gc_fid = (open (arguments.file_name, O_RDWR, 0644));
if (gc_fid == -1)
{
fprintf (stderr,
"%s (%d, process_requests): open failed. errno = %s.\n",
arguments.program_name, drone->index, (error_name (errno)));
fflush (stderr);
if (drone->DRONE_PPID == boss_pid)
(void) (kill (boss_pid, SIGCONT));
shutdown (0);
/*NOTREACHED*/
}
#ifdef DEBUG_1
printf ("%s (%d, process_requests): Starting (pid = %d, ppid = %d).\n",
arguments.program_name, drone->index,
drone->DRONE_PID, drone->DRONE_PPID);
fflush (stdout);
#endif
if ((result = (fstat (gc_fid, &file_info))) == -1)
{
fprintf (stderr,
"%s (%d, process_requests): fstat failed. errno = %s.\n",
arguments.program_name, drone->index, (error_name (errno)));
fflush (stderr);
}
/* Force O_SYNC only if we are dealing with a raw device. */
if ((result == -1) || ((file_info.st_mode & S_IFMT) == S_IFCHR))
{
if ((flags = (fcntl (gc_fid, F_GETFL, 0))) == -1)
{
fprintf
(stderr,
"%s (%d, process_requests): fcntl (F_GETFL) failed. errno = %s.\n",
arguments.program_name, drone->index, (error_name (errno)));
fflush (stderr);
}
else
{
flags |= O_SYNC;
if ((fcntl (gc_fid, F_SETFL, flags)) == -1)
{
fprintf
(stderr,
"%s (%d, process_requests): fcntl (F_SETFL) failed. errno = %s.\n",
arguments.program_name, drone->index, (error_name (errno)));
fflush (stderr);
}
}
}
UX_sigemptyset (&non_blocking_signal_mask);
UX_sigemptyset (&blocking_signal_mask);
UX_sigaddset ((&blocking_signal_mask), SIGCONT);
UX_sigaddset ((&blocking_signal_mask), SIGQUIT);
UX_sigprocmask (SIG_SETMASK, (&blocking_signal_mask), 0);
posix_signal (SIGQUIT, abort_operation);
posix_signal (SIGCONT, continue_running);
if ((setjmp (abort_point)) == 0)
{
count = drone->index;
drone->state = drone_idle;
if (drone->DRONE_PPID == boss_pid)
(void) (kill (boss_pid, SIGCONT));
}
else
goto redo_dispatch;
for (; 1; count++)
{
timeout.tv_sec = 6;
timeout.tv_usec = 0;
UX_sigprocmask (SIG_SETMASK, (&non_blocking_signal_mask), 0);
result = (select (0, 0, 0, 0, &timeout));
UX_sigprocmask (SIG_SETMASK, (&blocking_signal_mask), 0);
if ((drone->state != drone_idle)
|| ((result == -1) && (errno == EINTR)))
{
if (result != -1)
{
fprintf (stderr,
"\n%s (%d, process_requests): request after timeout %d.\n",
arguments.program_name, drone->index, drone->state);
fflush (stderr);
}
redo_dispatch:
switch (drone->state)
{
default:
fprintf (stderr,
"\n%s (%d, process_requests): Unknown/bad operation %d.\n",
arguments.program_name, drone->index, drone->state);
fflush (stderr);
shutdown (0);
/*NOTREACHED*/
case drone_idle:
break;
case drone_aborting:
#ifdef DEBUG_1
printf ("\n%s (%d, process_requests): Aborting.",
arguments.program_name, drone->index);
fflush (stdout);
#endif
drone->buffer_index = -1;
current_position = -1;
break;
case drone_reading:
case drone_writing:
{
/* Can't use buffer->bottom because the shared memory may be
attached at a different address!
*/
int saved_errno;
enum drone_state operation;
char * operation_name, * buffer_address;
struct buffer_info * buffer;
struct gc_queue_entry * entry;
operation = drone->state;
buffer_index = (drone->buffer_index);
buffer = (gc_buffers + buffer_index);
entry = ((struct gc_queue_entry *)
(((char *) drone) + (drone->entry_offset)));
entry->error_code = 0;
operation_name = ((operation == drone_reading) ? "read" : "write");
buffer_address = (shared_memory + (arguments.bufsiz * buffer_index));
#ifdef DEBUG_1
printf ("\n%s (%d, process_requests %s): Buffer index = %d.\n",
arguments.program_name, drone->index, operation_name,
buffer_index);
printf ("\tBuffer address = 0x%lx; Position = 0x%lx; Size = 0x%lx.",
buffer_address, buffer->position, buffer->size);
fflush (stdout);
#endif
UX_sigprocmask (SIG_SETMASK, (&non_blocking_signal_mask), 0);
result = (retrying_file_operation
(((operation == drone_reading)
? ((int (*) ()) read)
: ((int (*) ()) write)),
gc_fid, buffer_address,
buffer->position, buffer->size, operation_name, NULL,
¤t_position, always_one));
saved_errno = errno;
UX_sigprocmask (SIG_SETMASK, (&blocking_signal_mask), 0);
if (result == -1)
{
buffer->state = ((operation == drone_reading)
? buffer_read_error
: buffer_write_error);
drone->buffer_index = -1;
entry->drone_index = -1;
entry->error_code = saved_errno;
entry->state = entry_error;
current_position = -1;
#ifdef DEBUG
printf ("\n%s (%d, process_requests): %s error (errno = %s).\n",
arguments.program_name, drone->index, operation_name,
(error_name (saved_errno)));
fflush (stdout);
#endif
}
else
{
buffer->state = ((operation == drone_reading)
? buffer_ready
: buffer_idle);
drone->buffer_index = -1;
entry->drone_index = -1;
if (operation == drone_writing)
{
entry->retry_count = 0;
entry->state = entry_idle;
}
#ifdef DEBUG_1
printf ("\n%s (%d, process_requests %s): Done.",
arguments.program_name, drone->index, operation_name);
fflush (stdout);
#endif
}
}
}
count = 0;
drone->state = drone_idle;
read_mask = (* wait_mask);
if ((read_mask & my_mask) == my_mask)
(void) (kill (boss_pid, SIGCONT));
}
else if (result == 0)
{
if (count == arguments.tdron)
{
count = 0;
if ((kill (boss_pid, 0)) == -1)
shutdown (-1);
}
read_mask = (* wait_mask);
if ((read_mask & my_mask) == my_mask)
{
fprintf (stderr,
"\n%s (%d, process_requests): signal deadlock (%s)!\n",
arguments.program_name, drone->index,
((read_mask == ((unsigned long) -1)) ? "any" : "me"));
fflush (stderr);
drone->state = drone_idle; /* !! */
(void) (kill (boss_pid, SIGCONT));
}
}
}
}
static void
DEFUN_VOID (start_drones)
{
pid_t my_pid;
int counter, cpid;
struct drone_info *gc_drones, *drone;
my_pid = (getpid ());
shared_memory = (shmat (arguments.shmid, ((char *) 0), 0));
if (shared_memory == ((char *) -1))
{
fprintf (stderr,
"\
%s (start_drones): Unable to attach shared memory segment %d (errno = %s).\n",
arguments.program_name, arguments.shmid, (error_name (errno)));
fflush (stderr);
sleep (10);
kill (boss_pid, SIGCONT);
exit (1);
}
#ifdef DEBUG_1
printf ("%s (start_drones): Attached shared memory at address = 0x%lx.\n",
arguments.program_name, ((long) shared_memory));
fflush (stdout);
#endif
posix_signal (SIGINT, SIG_IGN);
posix_signal (SIGQUIT, SIG_IGN);
posix_signal (SIGHUP, shutdown);
posix_signal (SIGTERM, shutdown);
gc_buffers = ((struct buffer_info *)
(shared_memory + (arguments.nbuf * arguments.bufsiz)));
gc_drones = ((struct drone_info *) (gc_buffers + arguments.nbuf));
drone_version = ((unsigned long *) (gc_drones + arguments.tdron));
wait_mask = (drone_version + 1);
if ((* drone_version) != ((unsigned long) DRONE_VERSION_NUMBER))
{
fprintf (stderr,
"%s (start_drones): stored drone version != drone version.\n",
arguments.program_name);
fprintf (stderr, "\t*drone_version = %ld; DRONE_VERSION_NUMBER = %ld.\n",
(* drone_version), ((unsigned long) DRONE_VERSION_NUMBER));
fflush (stderr);
kill (boss_pid, SIGCONT);
exit (1);
}
for (counter = 1, drone = (gc_drones + (arguments.sdron + 1));
counter < arguments.ndron;
counter++, drone ++)
{
if ((cpid = (fork ())) == 0)
{
drone->DRONE_PPID = my_pid;
process_requests (drone);
/*NOTREACHED*/
}
else if (cpid == -1)
{
fprintf (stderr,
"%s (start_drones): fork failed; errno = %s.\n",
arguments.program_name, (error_name (errno)));
fflush (stderr);
}
}
drone = (gc_drones + arguments.sdron);
drone->DRONE_PPID = boss_pid;
/* This is non-portable behavior to prevent zombies from being created. */
if (arguments.ndron != 1)
posix_signal (SIGCHLD, SIG_IGN);
process_requests (drone);
/*NOTREACHED*/
}
void
DEFUN (main, (argc, argv), int argc AND char ** argv)
{
int count, nargs;
static char err_buf[1024];
#if defined(DEBUG) || defined(DEBUG_1) || defined(DEBUG_2)
static char out_buf[1024];
setvbuf (stdout, &out_buf[0], _IOFBF, (sizeof (out_buf)));
#endif
setvbuf (stderr, &err_buf[0], _IOFBF, (sizeof (err_buf)));
#ifdef DEBUG_2
printf ("%s (main): Arguments =\n", argv[0]);
for (count = 1; count < argc; count++)
printf ("\t%s\n", argv[count]);
fflush (stdout);
#endif
nargs = ((sizeof (command_line)) / (sizeof (struct argdesc)));
boss_pid = (getppid ());
if (argc != nargs)
{
fprintf (stderr,
"%s (main): Wrong number of arguments (got %d, expected %d).\n",
argv[0], (argc - 1), (nargs - 1));
fflush (stderr);
kill (boss_pid, SIGCONT);
exit (1);
}
for (count = 0; count < nargs; count++)
{
if (command_line[count].format == STRING_FMT)
(* ((char **) command_line[count].location)) = argv[count];
else
sscanf (argv[count],
command_line[count].format,
command_line[count].location);
}
#ifdef DEBUG_2
printf ("%s (main): Parsed arguments =\n", argv[0]);
for (count = 0; count < nargs; count++)
{
if (command_line[count].format == STRING_FMT)
printf ("\t%s\t= %s\n",
command_line[count].name,
(* ((char **) (command_line[count].location))));
else
printf ("\t%s\t= %d\n",
command_line[count].name,
(* ((int *) (command_line[count].location))));
}
fflush (stdout);
#endif
start_drones ();
/*NOTREACHED*/
}
#define MAIN main
#endif /* HAVE_SYSV_SHARED_MEMORY */
#ifndef MAIN
void
DEFUN (main, (argc, argv), int argc AND char ** argv)
{
fprintf (stderr, "%s: Not implemented.\n", (argv[0]));
fflush (stderr);
exit (1);
}
#endif /* MAIN */