signlq16.c

来自「开放源码的编译器open watcom 1.6.0版的源代码」· C语言 代码 · 共 150 行

/****************************************************************************
*
*                            Open Watcom Project
*
*    Portions Copyright (c) 1983-2002 Sybase, Inc. All Rights Reserved.
*
*  ========================================================================
*
*    This file contains Original Code and/or Modifications of Original
*    Code as defined in and that are subject to the Sybase Open Watcom
*    Public License version 1.0 (the 'License'). You may not use this file
*    except in compliance with the License. BY USING THIS FILE YOU AGREE TO
*    ALL TERMS AND CONDITIONS OF THE LICENSE. A copy of the License is
*    provided with the Original Code and Modifications, and is also
*    available at www.sybase.com/developer/opensource.
*
*    The Original Code and all software distributed under the License are
*    distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
*    EXPRESS OR IMPLIED, AND SYBASE AND ALL CONTRIBUTORS HEREBY DISCLAIM
*    ALL SUCH WARRANTIES, INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF
*    MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR
*    NON-INFRINGEMENT. Please see the License for the specific language
*    governing rights and limitations under the License.
*
*  ========================================================================
*
* Description:  WHEN YOU FIGURE OUT WHAT THIS FILE DOES, PLEASE
*               DESCRIBE IT HERE!
*
****************************************************************************/


#include "variety.h"
#include <sys/types.h>
#include <stdio.h>
#include <errno.h>
#include <signal.h>
#include <sys/kernel.h>
#include <sys/proc_msg.h>
#include <i86.h>

extern  void    (*__abort)( void );
extern  void    __sigabort( void );


/*
 * This table is fished into by the kernel so do not change its
 * size or layout.
 */
struct __sigtable {
    void                (__SIG_FAR *stub)();
    struct sigaction    acttable[_SIGMAX];
    } _SignalTable;



_WCRTLINK void (*signal( int sig, void (*func)(int) ))(int)
{
    struct sigaction act;

#if defined( __SMALL_CODE__ )
    /* this if is necessary in small code models to get the
       correct near ==> far pointer conversions */
    if( func == SIG_ERR ) {
        act.sa_handler = __FAR_SIG_ERR;
    } else if( func == SIG_DFL ) {
        act.sa_handler = __FAR_SIG_DFL;
    } else if( func == SIG_IGN ) {
        act.sa_handler = __FAR_SIG_IGN;
    } else if( func == SIG_HOLD ) {
        act.sa_handler = __FAR_SIG_HOLD;
    } else {
        act.sa_handler = func;
    }
#else
    act.sa_handler = func;
#endif
    act.sa_mask = 0;
    act.sa_flags = 0;

    if( sigaction(sig, &act, &act) )
        return SIG_ERR;
    return( (void (*)(int))act.sa_handler );
}



_WCRTLINK int sigaction(sig, act, oact)
int sig;
register const struct sigaction *act;
register struct sigaction *oact;
{
    extern void __sigstub();
    static int  first = 1;
    union {
        struct _proc_signal         s;
        struct _proc_signal_reply   r;
    } msg;

    /*
     * Tell the process manager the address of our signal table.
     */
    if( first ) {
        _SignalTable.stub = &__sigstub;
        msg.s.type = _PROC_SIGNAL;
        msg.s.subtype = _SIGTABLE;
        msg.s.segment = FP_SEG( &_SignalTable );
        msg.s.offset = (long)FP_OFF( &_SignalTable );
        msg.s.zero1 = 0;
        Send( PROC_PID, &msg.s, &msg.r, sizeof( msg.s ), sizeof( msg.r ) );
        first = 0;

        __abort = __sigabort;           /* change the abort rtn address */
    }

    if( (sig < _SIGMIN)  ||  (sig > _SIGMAX) ) {
        errno = EINVAL;
        return( -1 );
    }

    /*
     * The process manager will stuff the signal table itself
     * before the send returns. It does the stuffing because
     * the update must be atomic (user procs don't do cli ... sti).
     */
    if( act ) {
        msg.s.type = _PROC_SIGNAL;
        msg.s.subtype = _SIGACT;
        msg.s.signum = sig;
        msg.s.segment = FP_SEG( act->sa_handler );
        msg.s.offset = (long)FP_OFF( act->sa_handler );
        msg.s.mask = act->sa_mask;
        msg.s.zero1 = 0;
    }

    if( oact )
        *oact = _SignalTable.acttable[sig-1];

    if( act ) {
        Send( PROC_PID, &msg.s, &msg.r, sizeof( msg.s ), sizeof( msg.r ) );

        if( msg.r.status != EOK ) {
            errno = msg.r.status;
            return( -1 );
        }
    }

    return( 0 );
}