NetBSD/gnu/libexec/uucp/libunix/signal.c

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/* signal.c
Signal handling routines.
Copyright (C) 1992 Ian Lance Taylor
This file is part of the Taylor UUCP package.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the
License, or (at your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
The author of the program may be contacted at ian@airs.com or
c/o Infinity Development Systems, P.O. Box 520, Waltham, MA 02254.
*/
#include "uucp.h"
#include "uudefs.h"
#include "sysdep.h"
#include "system.h"
#include <errno.h>
/* Signal handling routines. When we catch a signal, we want to set
the appropriate elements of afSignal and afLog_signal to TRUE. If
we are on a system which restarts system calls, we may also want to
longjmp out. On a system which does not restart system calls,
these signal handling routines are well-defined by ANSI C. */
#if HAVE_RESTARTABLE_SYSCALLS
volatile sig_atomic_t fSjmp;
volatile jmp_buf sSjmp_buf;
#endif /* HAVE_RESTARTABLE_SYSCALLS */
/* Some systems, such as SunOS, have a SA_INTERRUPT bit that must be
set in the sigaction structure to force system calls to be
interrupted. */
#ifndef SA_INTERRUPT
#define SA_INTERRUPT 0
#endif
/* The SVR3 sigset function can be called just like signal, unless
system calls are restarted which is extremely unlikely; we prevent
this case in sysh.unx. */
#if HAVE_SIGSET && ! HAVE_SIGACTION && ! HAVE_SIGVEC
#define signal sigset
#endif
/* The sigvec structure changed from 4.2BSD to 4.3BSD. These macros
make the 4.3 code backward compatible. */
#ifndef SV_INTERRUPT
#define SV_INTERRUPT 0
#endif
#if ! HAVE_SIGVEC_SV_FLAGS
#define sv_flags sv_onstack
#endif
/* Catch a signal. Reinstall the signal handler if necessary, set the
appropriate variables, and do a longjmp if necessary. */
RETSIGTYPE
ussignal (isig)
int isig;
{
int iindex;
#if ! HAVE_SIGACTION && ! HAVE_SIGVEC && ! HAVE_SIGSET
(void) signal (isig, ussignal);
#endif
switch (isig)
{
default: iindex = INDEXSIG_SIGHUP; break;
#ifdef SIGINT
case SIGINT: iindex = INDEXSIG_SIGINT; break;
#endif
#ifdef SIGQUIT
case SIGQUIT: iindex = INDEXSIG_SIGQUIT; break;
#endif
#ifdef SIGTERM
case SIGTERM: iindex = INDEXSIG_SIGTERM; break;
#endif
#ifdef SIGPIPE
case SIGPIPE: iindex = INDEXSIG_SIGPIPE; break;
#endif
}
afSignal[iindex] = TRUE;
afLog_signal[iindex] = TRUE;
#if HAVE_RESTARTABLE_SYSCALLS
if (fSjmp)
longjmp (sSjmp_buf, 1);
#endif /* HAVE_RESTARTABLE_SYSCALLS */
}
/* Prepare to catch a signal. This is basically the ANSI C routine
signal, but it uses sigaction or sigvec instead if they are
available. If fforce is FALSE, we do not set the signal if it is
currently being ignored. If pfignored is not NULL and fforce is
FALSE, then *pfignored will be set to TRUE if the signal was
previously being ignored (if fforce is TRUE the value returned in
*pfignored is meaningless). If we can't change the signal handler
we give a fatal error. */
void
usset_signal (isig, pfn, fforce, pfignored)
int isig;
RETSIGTYPE (*pfn) P((int));
boolean fforce;
boolean *pfignored;
{
#if HAVE_SIGACTION
struct sigaction s;
if (! fforce)
{
(void) (sigemptyset (&s.sa_mask));
if (sigaction (isig, (struct sigaction *) NULL, &s) != 0)
ulog (LOG_FATAL, "sigaction (%d): %s", isig, strerror (errno));
if (s.sa_handler == SIG_IGN)
{
if (pfignored != NULL)
*pfignored = TRUE;
return;
}
if (pfignored != NULL)
*pfignored = FALSE;
}
s.sa_handler = pfn;
(void) (sigemptyset (&s.sa_mask));
s.sa_flags = SA_INTERRUPT;
if (sigaction (isig, &s, (struct sigaction *) NULL) != 0)
ulog (LOG_FATAL, "sigaction (%d): %s", isig, strerror (errno));
#else /* ! HAVE_SIGACTION */
#if HAVE_SIGVEC
struct sigvec s;
if (! fforce)
{
if (sigvec (isig, (struct sigvec *) NULL, &s) != 0)
ulog (LOG_FATAL, "sigvec (%d): %s", isig, strerror (errno));
if (s.sv_handler == SIG_IGN)
{
if (pfignored != NULL)
*pfignored = TRUE;
return;
}
if (pfignored != NULL)
*pfignored = FALSE;
}
s.sv_handler = pfn;
s.sv_mask = 0;
s.sv_flags = SV_INTERRUPT;
if (sigvec (isig, &s, (struct sigvec *) NULL) != 0)
ulog (LOG_FATAL, "sigvec (%d): %s", isig, strerror (errno));
#else /* ! HAVE_SIGVEC */
if (! fforce)
{
if (signal (isig, SIG_IGN) == SIG_IGN)
{
if (pfignored != NULL)
*pfignored = TRUE;
return;
}
if (pfignored != NULL)
*pfignored = FALSE;
}
(void) signal (isig, pfn);
#endif /* ! HAVE_SIGVEC */
#endif /* ! HAVE_SIGACTION */
}
/* The routine called by the system independent code, which always
uses the same signal handler. */
void
usysdep_signal (isig)
int isig;
{
usset_signal (isig, ussignal, FALSE, (boolean *) NULL);
}