341 lines
7.0 KiB
C
341 lines
7.0 KiB
C
/*
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* Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
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* All rights reserved.
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*
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* By using this file, you agree to the terms and conditions set
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* forth in the LICENSE file which can be found at the top level of
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* the sendmail distribution.
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*/
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#include <sm/gen.h>
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SM_RCSID("@(#)$Id: signal.c,v 1.17 2005/06/14 23:07:20 ca Exp $")
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#if SM_CONF_SETITIMER
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# include <sm/time.h>
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#endif /* SM_CONF_SETITIMER */
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#include <errno.h>
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#include <stdlib.h>
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#include <time.h>
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#include <unistd.h>
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#include <sm/clock.h>
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#include <sm/signal.h>
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#include <signal.h>
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#include <sm/string.h>
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unsigned int volatile InCriticalSection; /* >0 if inside critical section */
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int volatile PendingSignal; /* pending signal to resend */
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/*
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** SM_SIGNAL -- set a signal handler
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**
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** This is essentially old BSD "signal(3)".
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**
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** NOTE: THIS CAN BE CALLED FROM A SIGNAL HANDLER. DO NOT ADD
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** ANYTHING TO THIS ROUTINE UNLESS YOU KNOW WHAT YOU ARE
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** DOING.
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*/
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sigfunc_t
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sm_signal(sig, handler)
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int sig;
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sigfunc_t handler;
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{
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# if defined(SA_RESTART) || (!defined(SYS5SIGNALS) && !defined(BSD4_3))
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struct sigaction n, o;
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# endif /* defined(SA_RESTART) || (!defined(SYS5SIGNALS) && !defined(BSD4_3)) */
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/*
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** First, try for modern signal calls
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** and restartable syscalls
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*/
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# ifdef SA_RESTART
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(void) memset(&n, '\0', sizeof n);
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# if USE_SA_SIGACTION
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n.sa_sigaction = (void(*)(int, siginfo_t *, void *)) handler;
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n.sa_flags = SA_RESTART|SA_SIGINFO;
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# else /* USE_SA_SIGACTION */
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n.sa_handler = handler;
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n.sa_flags = SA_RESTART;
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# endif /* USE_SA_SIGACTION */
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if (sigaction(sig, &n, &o) < 0)
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return SIG_ERR;
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return o.sa_handler;
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# else /* SA_RESTART */
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/*
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** Else check for SYS5SIGNALS or
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** BSD4_3 signals
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*/
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# if defined(SYS5SIGNALS) || defined(BSD4_3)
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# ifdef BSD4_3
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return signal(sig, handler);
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# else /* BSD4_3 */
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return sigset(sig, handler);
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# endif /* BSD4_3 */
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# else /* defined(SYS5SIGNALS) || defined(BSD4_3) */
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/*
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** Finally, if nothing else is available,
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** go for a default
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*/
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(void) memset(&n, '\0', sizeof n);
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n.sa_handler = handler;
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if (sigaction(sig, &n, &o) < 0)
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return SIG_ERR;
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return o.sa_handler;
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# endif /* defined(SYS5SIGNALS) || defined(BSD4_3) */
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# endif /* SA_RESTART */
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}
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/*
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** SM_BLOCKSIGNAL -- hold a signal to prevent delivery
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**
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** Parameters:
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** sig -- the signal to block.
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**
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** Returns:
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** 1 signal was previously blocked
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** 0 signal was not previously blocked
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** -1 on failure.
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*/
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int
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sm_blocksignal(sig)
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int sig;
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{
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# ifdef BSD4_3
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# ifndef sigmask
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# define sigmask(s) (1 << ((s) - 1))
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# endif /* ! sigmask */
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return (sigblock(sigmask(sig)) & sigmask(sig)) != 0;
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# else /* BSD4_3 */
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# ifdef ALTOS_SYSTEM_V
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sigfunc_t handler;
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handler = sigset(sig, SIG_HOLD);
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if (handler == SIG_ERR)
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return -1;
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else
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return handler == SIG_HOLD;
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# else /* ALTOS_SYSTEM_V */
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sigset_t sset, oset;
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(void) sigemptyset(&sset);
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(void) sigaddset(&sset, sig);
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if (sigprocmask(SIG_BLOCK, &sset, &oset) < 0)
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return -1;
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else
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return sigismember(&oset, sig);
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# endif /* ALTOS_SYSTEM_V */
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# endif /* BSD4_3 */
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}
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/*
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** SM_RELEASESIGNAL -- release a held signal
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**
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** Parameters:
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** sig -- the signal to release.
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**
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** Returns:
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** 1 signal was previously blocked
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** 0 signal was not previously blocked
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** -1 on failure.
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*/
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int
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sm_releasesignal(sig)
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int sig;
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{
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# ifdef BSD4_3
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return (sigsetmask(sigblock(0) & ~sigmask(sig)) & sigmask(sig)) != 0;
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# else /* BSD4_3 */
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# ifdef ALTOS_SYSTEM_V
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sigfunc_t handler;
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handler = sigset(sig, SIG_HOLD);
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if (sigrelse(sig) < 0)
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return -1;
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else
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return handler == SIG_HOLD;
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# else /* ALTOS_SYSTEM_V */
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sigset_t sset, oset;
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(void) sigemptyset(&sset);
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(void) sigaddset(&sset, sig);
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if (sigprocmask(SIG_UNBLOCK, &sset, &oset) < 0)
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return -1;
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else
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return sigismember(&oset, sig);
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# endif /* ALTOS_SYSTEM_V */
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# endif /* BSD4_3 */
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}
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/*
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** PEND_SIGNAL -- Add a signal to the pending signal list
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**
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** Parameters:
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** sig -- signal to add
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**
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** Returns:
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** none.
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**
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** NOTE: THIS CAN BE CALLED FROM A SIGNAL HANDLER. DO NOT ADD
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** ANYTHING TO THIS ROUTINE UNLESS YOU KNOW WHAT YOU ARE
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** DOING.
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*/
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void
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pend_signal(sig)
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int sig;
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{
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int sigbit;
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int save_errno = errno;
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#if SM_CONF_SETITIMER
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struct itimerval clr;
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#endif /* SM_CONF_SETITIMER */
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/*
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** Don't want to interrupt something critical, hence delay
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** the alarm for one second. Hopefully, by then we
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** will be out of the critical section. If not, then
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** we will just delay again. The events to be run will
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** still all be run, maybe just a little bit late.
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*/
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switch (sig)
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{
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case SIGHUP:
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sigbit = PEND_SIGHUP;
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break;
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case SIGINT:
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sigbit = PEND_SIGINT;
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break;
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case SIGTERM:
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sigbit = PEND_SIGTERM;
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break;
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case SIGUSR1:
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sigbit = PEND_SIGUSR1;
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break;
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case SIGALRM:
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/* don't have to pend these */
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sigbit = 0;
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break;
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default:
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/* If we get here, we are in trouble */
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abort();
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/* NOTREACHED */
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/* shut up stupid compiler warning on HP-UX 11 */
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sigbit = 0;
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break;
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}
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if (sigbit != 0)
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PendingSignal |= sigbit;
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(void) sm_signal(SIGALRM, sm_tick);
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#if SM_CONF_SETITIMER
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clr.it_interval.tv_sec = 0;
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clr.it_interval.tv_usec = 0;
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clr.it_value.tv_sec = 1;
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clr.it_value.tv_usec = 0;
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(void) setitimer(ITIMER_REAL, &clr, NULL);
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#else /* SM_CONF_SETITIMER */
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(void) alarm(1);
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#endif /* SM_CONF_SETITIMER */
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errno = save_errno;
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}
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/*
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** SM_ALLSIGNALS -- act on all signals
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**
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** Parameters:
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** block -- whether to block or release all signals.
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**
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** Returns:
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** none.
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*/
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void
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sm_allsignals(block)
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bool block;
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{
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# ifdef BSD4_3
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# ifndef sigmask
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# define sigmask(s) (1 << ((s) - 1))
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# endif /* ! sigmask */
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if (block)
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{
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int mask = 0;
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mask |= sigmask(SIGALRM);
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mask |= sigmask(SIGCHLD);
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mask |= sigmask(SIGHUP);
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mask |= sigmask(SIGINT);
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mask |= sigmask(SIGTERM);
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mask |= sigmask(SIGUSR1);
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(void) sigblock(mask);
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}
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else
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sigsetmask(0);
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# else /* BSD4_3 */
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# ifdef ALTOS_SYSTEM_V
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if (block)
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{
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(void) sigset(SIGALRM, SIG_HOLD);
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(void) sigset(SIGCHLD, SIG_HOLD);
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(void) sigset(SIGHUP, SIG_HOLD);
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(void) sigset(SIGINT, SIG_HOLD);
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(void) sigset(SIGTERM, SIG_HOLD);
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(void) sigset(SIGUSR1, SIG_HOLD);
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}
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else
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{
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(void) sigset(SIGALRM, SIG_DFL);
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(void) sigset(SIGCHLD, SIG_DFL);
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(void) sigset(SIGHUP, SIG_DFL);
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(void) sigset(SIGINT, SIG_DFL);
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(void) sigset(SIGTERM, SIG_DFL);
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(void) sigset(SIGUSR1, SIG_DFL);
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}
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# else /* ALTOS_SYSTEM_V */
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sigset_t sset;
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(void) sigemptyset(&sset);
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(void) sigaddset(&sset, SIGALRM);
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(void) sigaddset(&sset, SIGCHLD);
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(void) sigaddset(&sset, SIGHUP);
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(void) sigaddset(&sset, SIGINT);
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(void) sigaddset(&sset, SIGTERM);
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(void) sigaddset(&sset, SIGUSR1);
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(void) sigprocmask(block ? SIG_BLOCK : SIG_UNBLOCK, &sset, NULL);
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# endif /* ALTOS_SYSTEM_V */
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# endif /* BSD4_3 */
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}
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/*
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** SM_SIGNAL_NOOP -- A signal no-op function
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**
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** Parameters:
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** sig -- signal received
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**
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** Returns:
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** SIGFUNC_RETURN
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*/
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/* ARGSUSED */
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SIGFUNC_DECL
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sm_signal_noop(sig)
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int sig;
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{
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int save_errno = errno;
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FIX_SYSV_SIGNAL(sig, sm_signal_noop);
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errno = save_errno;
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return SIGFUNC_RETURN;
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}
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