OS/2 Professional/OS2PRO194.ISO/os2/prgramer/hotkeys/hook_kbs.doc

Text File | 1992-10-17 | 22.3 KB | 455 lines

Document File for hook_kbs program

From : Morton F. Kaplon  CIS : 73457,437
       1047 Johnston Drive
       Bethlehem PA 18017
       [phone]

Revised and Updated : Sat  10-17-1992

Subject : Hooking the Keyboard in OS/2 2.0 and Assigning HotKeys

INTRODUCTION

  HOOK_KBS is an OS/2 equivalent of a DOS TRS program. HotKeys are defined in
  a user created data file that assigns to a HotKey a command to execute; the
  data file is read by the program when loaded. Once loaded it intercepts the
  message stream and inspects all WM_CHAR messages, the equivalent in DOS of
  hooking the Keyboard Interrupt. When a key stroke meeting a HotKey
  definition is detected, it takes appropriate action otherwise it passes
  things along. The action taken is that of executing the assigned command
  which may be a COM, EXE, CMD, or BAT file or loading an instance of the
  command processor for either OS/2 or DOS. Thus you may activate a program or
  load an instance of the command processor at the flick of a HotKey without
  having to access an ICON.

  HOOK_KBS works in conjunction with HOOK_DLS, a dynamic link module. HOOK_KBS
  loads HOOK_DLS which captures Key Strokes (via sampling the systen nessage
  queue) from all Windows BUT Full Screen OS/2 or DOS. The KeyStrokes
  assignments are USER DEFINED in a data file named HOOK_KBS.DAT and the
  program recognizes keystrokes assigned to Shift-Alt-X  and Shift-Ctrl-X
  where X is 0.....9 and A...Z independent of case (The restriction on X is
  mine and is changeable of course). There are two combinations Shift-Alt-Del
  and Shift-Alt-Ins (both white keys) that are hard coded into the program.
  Shift-Alt-Del unloads the program and Shift-Alt-Ins pops up a small OS/2
  window in the center of the screen. These, as is true for the other key
  stroke combinations, may be called from anywhere, except for the Full Screen
  sessions noted above.

  To capture from Full Screen OS/2 or DOS would require an additional program
  but since my principal purpose was to create a program that would allow me
  to capture keystrokes independent of where I was working and since not using
  Full Screen has advantages in flexibility, I decided to go without it. For
  DOS windows you may in fact readily switch back and forth from Full Screen
  to Windowed via the Alt-Home combination so nothing is really lost there.

  The reason for requiring the triplet combination of Shift-Alt-X or
  Shift-Ctrl-X is that besides the large number of pre-assigned keys in OS/2,
  many programs use keystroke combinations for accessing specific features and
  if the Hot Key is to be useful, it should not conflict. I can only remember
  one program that I have seen over the years which used a Shift-Alt-X or
  Shift-Ctrl-X combination and so it seems to be a fairly safe one, and one
  that should not lead to conflicts. In filtering KeyStrokes the program
  rejects all but the combinations Shift-Alt-X and Shift-Ctrl-X so that the
  usual run of keystroke assignments of Alt-X or Ctrl-X and all Function key
  combinations will be unaffected. Keystrokes are recognized on the down
  stroke. I would note that the Shift-Alt or Shift-Ctrl combination is
  particularly easy to access on those keyboards where the Shift Key sits
  vertically between the Ctrl and Alt keys.

  As presently configured, once a key stroke combination has activated a
  program, using that combination a second time will not open an additional
  instance of the program but will switch back to the original. HOWEVER, IF
  the opened window was used to load another program (such as a command
  processor window might), then that window loses its unique identity and
  using the same HotKey will activate another copy. The reason for this is
  that the Identity of each window is determined by its Window title which is
  defined as "Alt-X" or "Ctl-X" where X is the key used. The window popped up
  with Shift-Alt-Ins has the letter ID "Ω". If another program is started from
  an open window, its program title is noted as "prgname.ext Alt-X" or
  "prgname.ext Ctl-X", where ext is the program's extension, and is thus not
  recognized as an already existing window title.

  The program is written in 32 bit Assembler.

OVERVIEW

  FILES REQUIRED TO CREATE HOOK_KBS.EXE AND HOOK_DLS.DLL

  DOSWIN32.MAC  Macros and Equates used by Programs

  HOOK_KBS.ASM  Source for Executable, Assembled and Linked by MLC-W386.CMD

  HOOK_DLS.DEF  Define file needed by IMPLIB and linker for HOOK_DLS.ASM

  HOOK_DLS.ASM  Source for HOOK_DLS.DLL, Assembled and linked by DLL-W386.CMD

  DLL-W386.CMD  IMPLIB and HOOK_DLS.DEF create C:\TOOLKT20\OS2LIB\HOOK_DLS.LIB
                MASM then assembles HOOK_DLS.ASM, LINK386 produces HOOK_DLS.DLL
                and HOOK_DLS.DLL is copied to C:\OS2\DLL directory.

  MLC-W386.CMD  MASM assembles HOOK_KBS.ASM and LINK386 produces HOOK_KBS.EXE


  To ASSEMBLE and LINK use the directory holding the above files as the
  default and the two commands below to produce the necessary files.

  DLL-W386  HOOK_DLS
  MLC-W386  HOOK_KBS

  FILES REQUIRED TO EXECUTE HOOK_KBS.EXE

  HOOK_KBS.DAT  Text File assigning programs to key strokes-read by HOOK_KBS.
                The user creates this file according to the structure outlined
                in the sample. MUST BE LOCATED IN C:\OS2. Edit the sample to
                fit your needs. Note that my assignment to C0 (Shift-Ctrl-0)
                displays a file which I have configured to list the Hot Key
                assignments. It serves as a useful reminder and I would
                recommend each user to make such an assignment. The one I
                use is a reasonable template and is included as HOT-KEY.MNU.
                All assignments fit on one screen in the default window size.

  HOOK_KBS.EXE  Exec file created above

  HOOK_DLS.DLL  Dynamic Load File Created Above - must be in C:\OS2\DLL

  DO NOT RENAME HOOK_DLS.* or HOOK_KBS.DAT as those names are coded into
                HOOK_KBS.ASM .

  The assembler used is MASM 6.0 including its built in MACROS for control
  structures and segment definitions.

  The 32 bit linker (LINK386) and the 32 bit library, along with the necessary
  INC files require the user to have the OS/2 TOOLKIT as well as MASM 6.0 to
  assemble the program.

  PROGRAM METHOD

  The system message queue is hooked using the HK_INPUT parameter. The
  function which samples the message queue is in HOOK_DLS.DLL. In the section
  "Input Hook", p. 30-2 in the Programming Guide, Vol. II, it states : "The
  system calls an input_hook function whenever the WinGetMsg or WinPeekMsg
  functions is about to return a message."

  The installed procedure, InputHook, in HOOK_DLS.DLL tests for WM_CHAR and
  when detected it further tests to see if the key combination Shift-Alt-X or
  Shift-Ctrl-X was struck, with X (as defined above) on the down stroke. If
  that criteria is met its POSTS to HOOK_KBS, via the API function WinPostMsg,
  the message WM_USER+300h. The mp1 parameter of that message holds a flag
  indicating whether Alt or Ctl was down and the mp2 parameter has the scan
  code for the key X that was struck.

  HOOK_KBS determines if the Key actually struck was assigned in the file
  HOOK_KBS.DAT and if so reads its parameters into the appropriate data
  structure required to execute the program. The Shift-Alt-Del key-stroke is
  assigned to removing the DLL from memory and closing the program, equivalent
  to unloading a TSR in DOS.

  The main program, HOOK_KBS.EXE, a PM program, sets up the hook, receives the
  message indicated above and takes the appropriate action depending on the
  Key Stroke. The program is established as Invisible and Not listed in the
  Window List. The program should be launched from an OS/2 window with the
  START command, i.e. "START HOOK_KBS". That command can be placed in a
  STARTUP.CMD for automatic loading. If you modify the file HOOK_KBS.DAT, you
  must unload HOOK_KBS by Shift-Alt-Del(white key) and then reload it to
  activate the new set of key assignments.

  The program automatically sets DPMI_DOS_API=ENABLED for programs whose
  session type (DOS full or windowed) is defined as 4 or 7 in hook_kbs.dat.
  This enables the Dos Protected Mode Interface for the DOS session. If the
  Session type value of 0 is used, DPMI is not enabled as above. It is
  interesting to note that setting that parameter is done by passing the
  DosStartSession data structure an address holding the text string above,
  even though the manual states that the field for a DOS session is reserved
  and must be ZERO. Unfortunately, there are quite a few errors in the OS/2
  Technical Library, but fortunately a lot of people to inform you about them.

  The flow of HOOK_KBS is delineated below. The same headings are listed in
  the source code in HOOK_KBS.ASM.


  PROGRAM FLOW : HOOK_KBS

  PRELIMINARIES
    Define Model and Calling Protocol
    Equates for Using Macros in .DATA section
    Equates for INC files
    Include file listings
    Prototype definitions for MASM
    Structure definition for storing info on Program Assignment to Keys

  .STACK   defines an 8KB stack

  .DATA    contains variables,parameters and strings required for .CODE section

  .CODE    outlined below

  ESTABLISH WINDOW
    WinInitialize             ;Initialize
    WinCreateMessageQueue     ;Create a Message Queue
    WinRegisterClass          ;Registers and identifies MainWinProc as name
                              ;of Procedure for messages
    WinCreateStdWindow        ;Creates window - here it is made Invisible,etc.

  IS HOOK_DLS.DLL LOADED ?    ;If yes, display message and exit

  ALLOCATE SHARED MEM AND STORE Handle Returned by WinCreateStdWindow
    This is required in order to pass the Handle to HOOK_DLS

  IS DATA FILE AVAILABLE AND VALID ?
    Load C:\OS2\HOOK_KBS.DAT  ;If it does not exist, exit with Error Message
    Get HOOK_KBS.DAT FileSize ;Required by program for subsequent use
    AllocateMemoryBuffer      ;Buffer for User Key assignments from DataFile
    Copy HOOK_KBS.DAT->Buffer ;Read File into Buffer
    Close HOOK_KBS.DAT        ;No longer needed
    Process Data in Buffer    ;If Format Not Correct, EXIT with  Message

  ALLOCATE MEMORY FOR SWITCH LIST STRUCTURE
    Do once since size needed can change as programs loaded/unloaded.

  ESTABLISH THE HOOK
    DosLoadModule             ;Loads HOOK_DLS.DLL
    DosQueryProcAddr          ;Get the address of the function in the DLL
    WinSetHook                ;Uses the Address above and HK_INPUT to set HOOK

  CREATE MAIN MESSAGE LOOP    ;Standard PM requirement but EXIT TEST is
                              ;commented out - a WM_QUIT message has no
                              ;impact here

  EXIT ROUTINE                ;Note this is commented out but is included
                              ;to demonstrate the overall structure of
                              ;setting up a PM program

  PROCESS MESSAGE QUEUE       ;The heart of a PM program

    MainWinProc               ;Processes message queue
      GET PASSED PARAMETERS FROM STACK

      RESTORE STACK POINTER AND STACK STATUS

      TEST SYSTEM QUEUE FOR MESSAGES FROM

        WM_CREATE

        WM_PAINT

        WM_CHAR

        WM_USER+300h          ;dispatched from hook_dls.dll
        IF msg = WM_USER+300h
          GET SCAN CODE AND ALT/CTRL FLAG
          IF Alt-Del struck
            Release DLL,Memory, Close Queues and Windows and Exit
          ELSE TEST FOR ASSIGNED KEYS
            SETUP DATA STRUCTURES FOR ACTIVATING HOT KEY
            GO THRU SWITCH LIST TO SEE IF HOT KEY ACTIVE
               IF ACTIVE SWITCH TO
               ELSE ACTIVATE HOT KEY PROGRAM
          ENDIF
        ENDIF

  END  PROGRAM FLOW : HOOK_KBS

  The flow of HOOK_DLS is delineated below. The same headings are listed in
  HOOK_KBS.DLL.

  PROGRAM FLOW : HOOK_DLS

  PRELIMINARIES
    Define Model and Calling Protocol
    Equates for INC files
    Include file listings

  .STACK   defines a 2KB stack

  .DATA    contains variables,parameters and strings required for .CODE section

  .CODE    delineated below

  ESTABLISH InputHook

  GET PARAMETERS FROM STACK

  GET ADDRESS OF SHARED MEMORY

      Get Handle Of Hook_kbs and Release Shared Memory

  IF WM_CHAR MESSAGE DETECTED
       Save mp1 and mp2 of WM_CHAR message
       Test for Shift Key,Alt/Ctrl Down and Valid Scan Key
       IF ScanCode & Shift & one of Alt or Ctrl down
           Send original message nowhere via WM_USER+0cfffh
           WinPostMessage to HOOK_KBS via WM_USER+300h ;with ALt/Ctrl Flag and
       ENDIF                                           ;ScanCode as parms
  ENDIF

  END PROGRAM FLOW : HOOK_DLS

DISCUSSION


  DOSWIN32.MAC  (Macros and Equates used by Program)

  This file contains the equates, EXTRN declarations, MACROS and Procedures
  used in the ASM files. The EXTRN declarations include many more than those
  used in the program but represent the accrued list of those used so far in
  my OS/2 assembler programming. (As I use a new one, I just add it).

  Included are two defines used in the .DATA section of hook_kbs.asm. The
  single most important MACRO is $CALL. This allows one to list parameters
  after the function name in the same order as they are listed in the OS/2 2.0
  Technical Manuals (and as called in C) . The macro pushes them on the stack
  in the correct order and resets the stack pointer after the call. It could
  clearly easily be extended to accomodate a longer parameter list. Following
  that are several useful macros and three others defined via equates.

  For displaying error messages and rudimentary inline debugging, there are
  three macros named $DosErrMsg, $WinErrMsg and $WinDebugMessage . The first
  two are meant to be called after an API function call to display the error
  number for the function used. Information on the success of the call is
  returned in EAX and this must be tested. Note EAX returns differently for
  DOS than for WIN calls. The user passes the text string for the Function
  used on the parameter line for the $XXXErrMsg. $DosErrMsg can only be used
  in Text Windows while $WinErrMsg only in PM windows.

  Finally there are several macros and procedures used for Binary <-> ASCII
  conversion for both Decimal and Hex, and also for displaying numerical
  results in Binary form. Not all of these are used but are included as a part
  of the overall package. Note that in 32 bit mode, it is most convenient to
  do all these conversion as DWORDS. These are required for numerical to ASCII
  conversion for the error messages.

  HOOK_DLS.DEF

  This file is required by both IMPLIB and LINK386 in the creation of
  HOOK_DLS.DLL. It identifies the function(s) exported from the DLL.

  HOOK_DLS.ASM

  This file represents the dynamic link code. It contains one function, named
  InputHook whose syntax is defined by OS/2 on page 30-2 of the Programming
  Guide, Vol II of the OS/2 Technical Library. This DLL monitors the system
  message queue and looks for the message WM_CHAR.

  Since I decided to use WinPostMsg to return information to hook_kbs, its
  handle is required in this program. The simplest way seemed to be to pass it
  in a shared memory region established by hook_kbs. Thus the first task done
  by the function InputHook, after setting itself up, is to get the address of
  the shared memory region and to obtain the handle of hook_kbs that was placed
  there by hook_kbs. After that is done, the shared memory is released.

  The program then waits for a message WM_CHAR and when that is detected the
  Keyboard Parameters are tested to see if they meet the HotKey criteria. If
  they do not, the message is passed on. If they do, a flag denoting whether
  the Alt or Ctrl key was down is equated to the mp1 parameter and the scan
  code value equated to the mp2 parameter of the message WM_USER+300h which is
  posted to HOOK_KBS by WinPostMsg.

  This DLL is released from memory when hook_kbs is closed.

  HOOK_KBS

  The first four WIN... function calls are a standard calling sequence in
  setting up a PM program. Since a PM program cannot display text using DOS
  write calls, error messages cannot be displayed with Window Message Calls
  until the Window is initialized with the first call.

  After the window is established a test is done to see if HOOK_DLS is loaded.
  If it is a message is given and the program terminates. A Shared Memory area
  is then established. Its sole use in this program is to furnish a method of
  passing HOOK_KBS's handle to HOOK_DLS. This is done following the call to
  DosAllocSharedMem. Note that eax is now tested for a non-zero value
  indicating an error, as contrasted to Win calls where a 0 returned in eax
  indicates an error.

  Next the program attempts to load the data file C:\OS2\HOOK_KBS.DAT. If it
  does not exist, an error message is displayed and the program terminates. If
  it loads, its size is obtained (note the calls are rather similar to what
  you would do in DOS) and that value is used to create a buffer to hold the
  file in memory. The file is read into the buffer and then closed. The big
  .WHILE loop reads the buffer and assigns the Addresses of the Executable
  program name and Command Line parameters and the Session type to the
  appropriate member of the Structure ExecOnKb and places a 0 at the end of
  strings in order that they meet the requirement of being ASCIIZ strings. If
  the count of characters read in the buffer does not equal the file size or
  if the data file was not properly formatted, an error message is displayed
  and the program terminated; the error message displays the number of bytes
  of the buffer processed when the program terminated.

  If everything is in order, a large memory block is defined to hold the data
  structure of the Switch List (which is used to determine if a program is
  loaded or not) and then the HOOK is established with the next three calls to
  DosLoadModule, DosQueryProcAddr and WinSetHook.

  The Main Message Loop is next established. Normally this loop is exited when
  WM_QUIT is received and the exit code is executed to gracefully terminate
  the program. However, in this program, to ensure that it is terminated only
  by the Key Combination Alt-Del, the Main Message Loop is not exitable (I
  have commented out the normal tests) and I have included the Exit code only
  for purposes of demonstration of what a more normal program would look like.

  The procedure MainWinProc examines the message queue. It first sets up to
  get the parameters passed on the stack and goes through a series of tests
  for specific messages. In a C program this would usually be a Case
  statement. There is no requirement for these tests to do anything in this
  case since the window is invisible but they are required to respond to
  certain system calls.

  The heart of the program is the test for WM_USER+300h . WM_USER defines a
  lower limit for message IDs that is (presumably) guaranteed not to conflict
  with any system messages. I have arbitrarily used WM_USER + 300h. HOOK_DLS
  uses this message ID in posting its information to this programs message
  queue. First a test is done to see whether Alt-Del was struck and if so, the
  system is closed and exited. If not, tests are done to see whether the Scan
  Code of the key struck is in the list read from HOOK_KBS.DAT. A test is
  first done to see if the (white)Insert key was struck, and if not, a test is
  done for the rest of the possible assignments.

  Depending on the key combination struck, the address of the program, address
  of the command line parameters, the Session Type for the Key Combination
  identified in the message and the Program Title ( based on the Key
  combination ) are obtained and inserted into the StartData structure
  required for the DosStartSession function. The Switch (Task) list is then
  examined to see if the HotKey program is already loaded and its identity
  unchanged. If it is, it is switched to, else DosStartSession is then called
  with appropriate parameters.

  Note that WinSetFocus is called before DosStartSession. The programs started
  by DosStartSession will not be in the foreground unless the program calling
  DosStartSession is in the foreground and it seems reasonable that programs
  called with a "HotKey" want to be in the foreground.

  The six procedures at the very end are just routines used by parts of the
  code in the program.

  I have found this program very useful, particularly with respect to programs
  using COM ports. Since OS/2 will not allow you to have two programs open at
  the same time that use the same COM port, this affords a rapid means of
  serially accessing programs sharing a common COM port. Another use I have
  found effective is to assign MENUS to some of the Hot Keys. In my sample
  HOOK_KBS.DAT file, the assignment Aq (Alt-q) to loadq.cmd, is a CMD file
  that displays a menu for editing a variety of different files and the
  assignment Ar (Alt-r) to viewref.cmd displays a menu whose choices allow you
  to View the various OnLine References of OS/2 and Toolkit20. You can readily
  assign any program assigned to an ICON to a hot key, presuming the program
  has an executable form or can be called as a parameter to another program.
  But by far I have found it an efficient expediter for rapidly accessing
  programs without changing anything on your DeskTop.

  As it was with TSR's in DOS, you must be careful of your assignments so that
  required keys in programs are not made unavailable. That stricture was
  reflected in my choice of keys to assign and reflects my particular
  concerns. A natural question to ask is - are there any problems with other
  programs that may be sampling the system message queue ?

  Included in OS/2 and the Toolkit are the following programs that I am aware
  of which are "resident" in the above sense:

    PULSE    From Productivity Group - Samples Processor Activity
    KWIKINF  From OS/2 ToolKit20     - An  OnLineReference Access
    PMSPY    From OS/2 ToolKit20     - A Message queue trace

  I have not detected any problems with HOOK_KBS loaded with any or all of the
  above programs active, independent of the order of loading.