209 lines
5.3 KiB
C
209 lines
5.3 KiB
C
/* signal.c
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Signal handling routines.
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Copyright (C) 1992 Ian Lance Taylor
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This file is part of the Taylor UUCP package.
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This program is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License as
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published by the Free Software Foundation; either version 2 of the
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License, or (at your option) any later version.
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This program is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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The author of the program may be contacted at ian@airs.com or
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c/o Cygnus Support, 48 Grove Street, Somerville, MA 02144.
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*/
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#include "uucp.h"
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#include "uudefs.h"
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#include "sysdep.h"
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#include "system.h"
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#include <errno.h>
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/* Signal handling routines. When we catch a signal, we want to set
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the appropriate elements of afSignal and afLog_signal to TRUE. If
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we are on a system which restarts system calls, we may also want to
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longjmp out. On a system which does not restart system calls,
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these signal handling routines are well-defined by ANSI C. */
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#if HAVE_RESTARTABLE_SYSCALLS
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volatile sig_atomic_t fSjmp;
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volatile jmp_buf sSjmp_buf;
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#endif /* HAVE_RESTARTABLE_SYSCALLS */
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/* Some systems, such as SunOS, have a SA_INTERRUPT bit that must be
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set in the sigaction structure to force system calls to be
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interrupted. */
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#ifndef SA_INTERRUPT
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#define SA_INTERRUPT 0
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#endif
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/* The SVR3 sigset function can be called just like signal, unless
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system calls are restarted which is extremely unlikely; we prevent
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this case in sysh.unx. */
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#if HAVE_SIGSET && ! HAVE_SIGACTION && ! HAVE_SIGVEC
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#define signal sigset
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#endif
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/* The sigvec structure changed from 4.2BSD to 4.3BSD. These macros
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make the 4.3 code backward compatible. */
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#ifndef SV_INTERRUPT
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#define SV_INTERRUPT 0
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#endif
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#if ! HAVE_SIGVEC_SV_FLAGS
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#define sv_flags sv_onstack
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#endif
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/* Catch a signal. Reinstall the signal handler if necessary, set the
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appropriate variables, and do a longjmp if necessary. */
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RETSIGTYPE
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ussignal (isig)
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int isig;
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{
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int iindex;
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#if ! HAVE_SIGACTION && ! HAVE_SIGVEC && ! HAVE_SIGSET
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(void) signal (isig, ussignal);
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#endif
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switch (isig)
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{
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default: iindex = INDEXSIG_SIGHUP; break;
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#ifdef SIGINT
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case SIGINT: iindex = INDEXSIG_SIGINT; break;
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#endif
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#ifdef SIGQUIT
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case SIGQUIT: iindex = INDEXSIG_SIGQUIT; break;
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#endif
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#ifdef SIGTERM
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case SIGTERM: iindex = INDEXSIG_SIGTERM; break;
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#endif
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#ifdef SIGPIPE
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case SIGPIPE: iindex = INDEXSIG_SIGPIPE; break;
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#endif
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}
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afSignal[iindex] = TRUE;
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afLog_signal[iindex] = TRUE;
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#if HAVE_RESTARTABLE_SYSCALLS
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if (fSjmp)
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longjmp (sSjmp_buf, 1);
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#endif /* HAVE_RESTARTABLE_SYSCALLS */
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}
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/* Prepare to catch a signal. This is basically the ANSI C routine
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signal, but it uses sigaction or sigvec instead if they are
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available. If fforce is FALSE, we do not set the signal if it is
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currently being ignored. If pfignored is not NULL and fforce is
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FALSE, then *pfignored will be set to TRUE if the signal was
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previously being ignored (if fforce is TRUE the value returned in
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*pfignored is meaningless). If we can't change the signal handler
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we give a fatal error. */
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void
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usset_signal (isig, pfn, fforce, pfignored)
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int isig;
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RETSIGTYPE (*pfn) P((int));
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boolean fforce;
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boolean *pfignored;
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{
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#if HAVE_SIGACTION
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struct sigaction s;
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if (! fforce)
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{
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(void) (sigemptyset (&s.sa_mask));
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if (sigaction (isig, (struct sigaction *) NULL, &s) != 0)
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ulog (LOG_FATAL, "sigaction (%d): %s", isig, strerror (errno));
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if (s.sa_handler == SIG_IGN)
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{
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if (pfignored != NULL)
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*pfignored = TRUE;
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return;
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}
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if (pfignored != NULL)
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*pfignored = FALSE;
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}
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s.sa_handler = pfn;
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(void) (sigemptyset (&s.sa_mask));
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s.sa_flags = SA_INTERRUPT;
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if (sigaction (isig, &s, (struct sigaction *) NULL) != 0)
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ulog (LOG_FATAL, "sigaction (%d): %s", isig, strerror (errno));
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#else /* ! HAVE_SIGACTION */
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#if HAVE_SIGVEC
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struct sigvec s;
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if (! fforce)
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{
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if (sigvec (isig, (struct sigvec *) NULL, &s) != 0)
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ulog (LOG_FATAL, "sigvec (%d): %s", isig, strerror (errno));
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if (s.sv_handler == SIG_IGN)
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{
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if (pfignored != NULL)
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*pfignored = TRUE;
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return;
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}
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if (pfignored != NULL)
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*pfignored = FALSE;
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}
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s.sv_handler = pfn;
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s.sv_mask = 0;
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s.sv_flags = SV_INTERRUPT;
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if (sigvec (isig, &s, (struct sigvec *) NULL) != 0)
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ulog (LOG_FATAL, "sigvec (%d): %s", isig, strerror (errno));
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#else /* ! HAVE_SIGVEC */
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if (! fforce)
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{
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if (signal (isig, SIG_IGN) == SIG_IGN)
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{
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if (pfignored != NULL)
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*pfignored = TRUE;
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return;
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}
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if (pfignored != NULL)
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*pfignored = FALSE;
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}
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(void) signal (isig, pfn);
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#endif /* ! HAVE_SIGVEC */
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#endif /* ! HAVE_SIGACTION */
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}
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/* The routine called by the system independent code, which always
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uses the same signal handler. */
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void
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usysdep_signal (isig)
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int isig;
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{
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usset_signal (isig, ussignal, FALSE, (boolean *) NULL);
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}
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