Carousel Volume 2 #1/carousel.iso/mactosh/lang/thinkc30.sit/onexit.c

C/C++ Source or Header | 1989-01-25 | 3.9 KB | 267 lines | [TEXT/KAHL]

/*
 *  onexit.c - Copyright (C) 1989 by Symantec Corp.  All rights reserved.
 *
 *  Shutdown routines installed with "onexit" are called only on NORMAL
 *  termination, i.e. calling "exit" or returning from "main".
 *
 *  Shutdown routines installed with "_onexit" are called on "ExitToShell"
 *  as well as on normal termination.
 *
 *  When initiating any other form of termination (e.g. "Launch"), the
 *  user can call "_exiting" to force shutdown routines to be called.
 *
 */

#ifndef _MacTypes_
#include <MacHeaders>
#endif

extern long ATrapHandler : 0x28;

typedef void (*Proc)();

Proc onexit(Proc);
Proc _onexit(Proc);
void _exiting(int);
void exit(int);
void nop(void);
void abort(void);

#define NPROCS        32

static struct proc { Proc proc; int always; } procs[NPROCS];
static int next = 0;
static Proc oldexit, oldES;
static char *ptrES;

static void normal_exit(void), newES(void);


/*
 *  exit - normal program termination
 *
 *  The exit status is ignored.
 *
 */

void
exit(i)
{
    asm {
        movea.l    0x6C(a5),a0
        jsr        (a0)            ;  call onexit vector
        _ExitToShell
    }
}


/*
 *  onexit - install user shutdown routine
 *
 */

Proc
onexit(proc)
Proc proc;
{
    register struct proc *p;

    if (next == NPROCS)
        return(0);

            /*  install proc in table  */

    p = &procs[next++];
    p->proc = proc;
/*    p->always = 0;    */
    if (!oldexit) {
        proc = normal_exit;

            /*  install onexit vector  */

        asm {
            move.l    0x6C(a5),oldexit
            move.l    proc,0x6C(a5)
        }
    }
    return(p->proc);
}


/*
 *  normal_exit - onexit vector
 *
 */

static void
normal_exit()
{
    _exiting(1);
}


/*
 *  _onexit - install a critical shutdown routine
 *
 *  Routines installed with "_onexit" are called even if the program does
 *  not terminate normally, provided only that "ExitToShell" is called.
 *
 */

Proc
_onexit(proc)
Proc proc;
{
    register struct proc *p;

    if (next == NPROCS)
        return(0);

            /*  install proc in table  */

    p = &procs[next++];
    p->proc = proc;
    p->always = 1;
    if (!oldES) {
        proc = newES;

            /*  save original ExitToShell  */

        asm {
            move.w    #0xA9F4,d0        ;  _ExitToShell
            _GetTrapAddress
            move.l    a0,oldES
        }

            /*  (64K ROM only) allocate intercept in sysheap  */

        asm {
            movea.l    proc,a0
            tst.w    ROM85
            bpl.s    @1
            moveq    #6,d0
            _NewPtr  SYS
            move.l    a0,ptrES
            move.w    #0x4EF9,(a0)    ;  JMP abs.L
            move.l    proc,2(a0)
@1        }

            /*  install ExitToShell intercept  */

        asm {
            move.w    #0xA9F4,d0        ;  _ExitToShell
            _SetTrapAddress
        }
    }
    return(p->proc);
}


/*
 *  newES - ExitToShell intercept
 *
 */

static void
newES()
{
    _exiting(0);
    ExitToShell();
}


/*
 *  _exiting - perform shutdown activity
 *
 *  The argument controls which shutdown routines should be called:
 *
 *        _exiting(1)        call all installed shutdown routines
 *        _exiting(0)        call only routines installed with "_onexit"
 *
 */

void
_exiting(normally)
{
    register struct proc *p;
    Proc proc;
    int i;

    SetUpA5();
    p = &procs[NPROCS];
    for (i = NPROCS; i--; ) {
        if (proc = (--p)->proc) {
            p->proc = 0;
            if (normally || p->always)
                (*proc)();
        }
    }

        /*  deallocate ExitToShell intercept  */

    asm {
        move.l    ptrES,d0
        beq.s    @1
        movea.l    d0,a0
        _DisposPtr
        clr.l    ptrES
@1    }

        /*  remove ExitToShell intercept  */

    asm {
        move.l    oldES,d0
        beq.s    @2
        movea.l    d0,a0
        move.w    #0xA9F4,d0
        _SetTrapAddress
        clr.l    oldES
@2    }

        /*  call original exit proc  */

    asm {
        movea.l    0x6C(a5),a0
        move.l    oldexit,d0
        beq.s    @3
        movea.l    d0,a0
@3        jsr        (a0)
    }
    oldexit = nop;
    RestoreA5();
}


/*
 *  nop - do nothing
 *
 */

static void
nop()
{
}


/*
 *  abort - abort execution
 *
 *  A debugger trap is issued if it looks like a debugger is installed.
 *
 */

void
abort()
{
    if (GetTrapAddress(0xA055) == GetTrapAddress(0xA89F)) {
        if ((ATrapHandler & Lo3Bytes) < ((long) ROMBase & Lo3Bytes))
            Debugger();
    }
    else {
        if (StripAddress(ATrapHandler) < StripAddress(ROMBase))
            Debugger();
    }
    ExitToShell();
}