diff options
Diffstat (limited to 'sendmail/libsm/signal.c')
| -rw-r--r-- | sendmail/libsm/signal.c | 340 |
1 files changed, 340 insertions, 0 deletions
diff --git a/sendmail/libsm/signal.c b/sendmail/libsm/signal.c new file mode 100644 index 0000000..ce2e242 --- /dev/null +++ b/sendmail/libsm/signal.c @@ -0,0 +1,340 @@ +/* + * 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. + */ + +#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; +} + |
