OpenSolaris_b135/cmd/sendmail/libsm/signal.c
/*
* Copyright (c) 2000-2001 Sendmail, Inc. and its suppliers.
* All rights reserved.
*
* By using this file, you agree to the terms and conditions set
* forth in the LICENSE file which can be found at the top level of
* the sendmail distribution.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <sm/gen.h>
SM_RCSID("@(#)$Id: signal.c,v 1.17 2005/06/14 23:07:20 ca Exp $")
#if SM_CONF_SETITIMER
# include <sm/time.h>
#endif /* SM_CONF_SETITIMER */
#include <errno.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
#include <sm/clock.h>
#include <sm/signal.h>
#include <signal.h>
#include <sm/string.h>
unsigned int volatile InCriticalSection; /* >0 if inside critical section */
int volatile PendingSignal; /* pending signal to resend */
/*
** SM_SIGNAL -- set a signal handler
**
** This is essentially old BSD "signal(3)".
**
** NOTE: THIS CAN BE CALLED FROM A SIGNAL HANDLER. DO NOT ADD
** ANYTHING TO THIS ROUTINE UNLESS YOU KNOW WHAT YOU ARE
** DOING.
*/
sigfunc_t
sm_signal(sig, handler)
int sig;
sigfunc_t handler;
{
# if defined(SA_RESTART) || (!defined(SYS5SIGNALS) && !defined(BSD4_3))
struct sigaction n, o;
# endif /* defined(SA_RESTART) || (!defined(SYS5SIGNALS) && !defined(BSD4_3)) */
/*
** First, try for modern signal calls
** and restartable syscalls
*/
# ifdef SA_RESTART
(void) memset(&n, '\0', sizeof n);
# if USE_SA_SIGACTION
n.sa_sigaction = (void(*)(int, siginfo_t *, void *)) handler;
n.sa_flags = SA_RESTART|SA_SIGINFO;
# else /* USE_SA_SIGACTION */
n.sa_handler = handler;
n.sa_flags = SA_RESTART;
# endif /* USE_SA_SIGACTION */
if (sigaction(sig, &n, &o) < 0)
return SIG_ERR;
return o.sa_handler;
# else /* SA_RESTART */
/*
** Else check for SYS5SIGNALS or
** BSD4_3 signals
*/
# if defined(SYS5SIGNALS) || defined(BSD4_3)
# ifdef BSD4_3
return signal(sig, handler);
# else /* BSD4_3 */
return sigset(sig, handler);
# endif /* BSD4_3 */
# else /* defined(SYS5SIGNALS) || defined(BSD4_3) */
/*
** Finally, if nothing else is available,
** go for a default
*/
(void) memset(&n, '\0', sizeof n);
n.sa_handler = handler;
if (sigaction(sig, &n, &o) < 0)
return SIG_ERR;
return o.sa_handler;
# endif /* defined(SYS5SIGNALS) || defined(BSD4_3) */
# endif /* SA_RESTART */
}
/*
** SM_BLOCKSIGNAL -- hold a signal to prevent delivery
**
** Parameters:
** sig -- the signal to block.
**
** Returns:
** 1 signal was previously blocked
** 0 signal was not previously blocked
** -1 on failure.
*/
int
sm_blocksignal(sig)
int sig;
{
# ifdef BSD4_3
# ifndef sigmask
# define sigmask(s) (1 << ((s) - 1))
# endif /* ! sigmask */
return (sigblock(sigmask(sig)) & sigmask(sig)) != 0;
# else /* BSD4_3 */
# ifdef ALTOS_SYSTEM_V
sigfunc_t handler;
handler = sigset(sig, SIG_HOLD);
if (handler == SIG_ERR)
return -1;
else
return handler == SIG_HOLD;
# else /* ALTOS_SYSTEM_V */
sigset_t sset, oset;
(void) sigemptyset(&sset);
(void) sigaddset(&sset, sig);
if (sigprocmask(SIG_BLOCK, &sset, &oset) < 0)
return -1;
else
return sigismember(&oset, sig);
# endif /* ALTOS_SYSTEM_V */
# endif /* BSD4_3 */
}
/*
** SM_RELEASESIGNAL -- release a held signal
**
** Parameters:
** sig -- the signal to release.
**
** Returns:
** 1 signal was previously blocked
** 0 signal was not previously blocked
** -1 on failure.
*/
int
sm_releasesignal(sig)
int sig;
{
# ifdef BSD4_3
return (sigsetmask(sigblock(0) & ~sigmask(sig)) & sigmask(sig)) != 0;
# else /* BSD4_3 */
# ifdef ALTOS_SYSTEM_V
sigfunc_t handler;
handler = sigset(sig, SIG_HOLD);
if (sigrelse(sig) < 0)
return -1;
else
return handler == SIG_HOLD;
# else /* ALTOS_SYSTEM_V */
sigset_t sset, oset;
(void) sigemptyset(&sset);
(void) sigaddset(&sset, sig);
if (sigprocmask(SIG_UNBLOCK, &sset, &oset) < 0)
return -1;
else
return sigismember(&oset, sig);
# endif /* ALTOS_SYSTEM_V */
# endif /* BSD4_3 */
}
/*
** PEND_SIGNAL -- Add a signal to the pending signal list
**
** Parameters:
** sig -- signal to add
**
** Returns:
** none.
**
** NOTE: THIS CAN BE CALLED FROM A SIGNAL HANDLER. DO NOT ADD
** ANYTHING TO THIS ROUTINE UNLESS YOU KNOW WHAT YOU ARE
** DOING.
*/
void
pend_signal(sig)
int sig;
{
int sigbit;
int save_errno = errno;
#if SM_CONF_SETITIMER
struct itimerval clr;
#endif /* SM_CONF_SETITIMER */
/*
** Don't want to interrupt something critical, hence delay
** the alarm for one second. Hopefully, by then we
** will be out of the critical section. If not, then
** we will just delay again. The events to be run will
** still all be run, maybe just a little bit late.
*/
switch (sig)
{
case SIGHUP:
sigbit = PEND_SIGHUP;
break;
case SIGINT:
sigbit = PEND_SIGINT;
break;
case SIGTERM:
sigbit = PEND_SIGTERM;
break;
case SIGUSR1:
sigbit = PEND_SIGUSR1;
break;
case SIGALRM:
/* don't have to pend these */
sigbit = 0;
break;
default:
/* If we get here, we are in trouble */
abort();
/* NOTREACHED */
/* shut up stupid compiler warning on HP-UX 11 */
sigbit = 0;
break;
}
if (sigbit != 0)
PendingSignal |= sigbit;
(void) sm_signal(SIGALRM, sm_tick);
#if SM_CONF_SETITIMER
clr.it_interval.tv_sec = 0;
clr.it_interval.tv_usec = 0;
clr.it_value.tv_sec = 1;
clr.it_value.tv_usec = 0;
(void) setitimer(ITIMER_REAL, &clr, NULL);
#else /* SM_CONF_SETITIMER */
(void) alarm(1);
#endif /* SM_CONF_SETITIMER */
errno = save_errno;
}
/*
** SM_ALLSIGNALS -- act on all signals
**
** Parameters:
** block -- whether to block or release all signals.
**
** Returns:
** none.
*/
void
sm_allsignals(block)
bool block;
{
# ifdef BSD4_3
# ifndef sigmask
# define sigmask(s) (1 << ((s) - 1))
# endif /* ! sigmask */
if (block)
{
int mask = 0;
mask |= sigmask(SIGALRM);
mask |= sigmask(SIGCHLD);
mask |= sigmask(SIGHUP);
mask |= sigmask(SIGINT);
mask |= sigmask(SIGTERM);
mask |= sigmask(SIGUSR1);
(void) sigblock(mask);
}
else
sigsetmask(0);
# else /* BSD4_3 */
# ifdef ALTOS_SYSTEM_V
if (block)
{
(void) sigset(SIGALRM, SIG_HOLD);
(void) sigset(SIGCHLD, SIG_HOLD);
(void) sigset(SIGHUP, SIG_HOLD);
(void) sigset(SIGINT, SIG_HOLD);
(void) sigset(SIGTERM, SIG_HOLD);
(void) sigset(SIGUSR1, SIG_HOLD);
}
else
{
(void) sigset(SIGALRM, SIG_DFL);
(void) sigset(SIGCHLD, SIG_DFL);
(void) sigset(SIGHUP, SIG_DFL);
(void) sigset(SIGINT, SIG_DFL);
(void) sigset(SIGTERM, SIG_DFL);
(void) sigset(SIGUSR1, SIG_DFL);
}
# else /* ALTOS_SYSTEM_V */
sigset_t sset;
(void) sigemptyset(&sset);
(void) sigaddset(&sset, SIGALRM);
(void) sigaddset(&sset, SIGCHLD);
(void) sigaddset(&sset, SIGHUP);
(void) sigaddset(&sset, SIGINT);
(void) sigaddset(&sset, SIGTERM);
(void) sigaddset(&sset, SIGUSR1);
(void) sigprocmask(block ? SIG_BLOCK : SIG_UNBLOCK, &sset, NULL);
# endif /* ALTOS_SYSTEM_V */
# endif /* BSD4_3 */
}
/*
** SM_SIGNAL_NOOP -- A signal no-op function
**
** Parameters:
** sig -- signal received
**
** Returns:
** SIGFUNC_RETURN
*/
/* ARGSUSED */
SIGFUNC_DECL
sm_signal_noop(sig)
int sig;
{
int save_errno = errno;
FIX_SYSV_SIGNAL(sig, sm_signal_noop);
errno = save_errno;
return SIGFUNC_RETURN;
}