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Diffstat (limited to 'Src/signals.c')
| -rw-r--r-- | Src/signals.c | 748 |
1 files changed, 748 insertions, 0 deletions
diff --git a/Src/signals.c b/Src/signals.c new file mode 100644 index 000000000..5dc19dd22 --- /dev/null +++ b/Src/signals.c @@ -0,0 +1,748 @@ +/* + * signals.c - signals handling code + * + * This file is part of zsh, the Z shell. + * + * Copyright (c) 1992-1997 Paul Falstad + * All rights reserved. + * + * Permission is hereby granted, without written agreement and without + * license or royalty fees, to use, copy, modify, and distribute this + * software and to distribute modified versions of this software for any + * purpose, provided that the above copyright notice and the following + * two paragraphs appear in all copies of this software. + * + * In no event shall Paul Falstad or the Zsh Development Group be liable + * to any party for direct, indirect, special, incidental, or consequential + * damages arising out of the use of this software and its documentation, + * even if Paul Falstad and the Zsh Development Group have been advised of + * the possibility of such damage. + * + * Paul Falstad and the Zsh Development Group specifically disclaim any + * warranties, including, but not limited to, the implied warranties of + * merchantability and fitness for a particular purpose. The software + * provided hereunder is on an "as is" basis, and Paul Falstad and the + * Zsh Development Group have no obligation to provide maintenance, + * support, updates, enhancements, or modifications. + * + */ + +#include "zsh.mdh" +#include "signals.pro" + +/* Array describing the state of each signal: an element contains * + * 0 for the default action or some ZSIG_* flags ored together. */ + +/**/ +int sigtrapped[VSIGCOUNT]; + +/* trap functions for each signal */ + +/**/ +List sigfuncs[VSIGCOUNT]; + +/* Variables used by signal queueing */ + +/**/ +int queueing_enabled, queue_front, queue_rear; +/**/ +int signal_queue[MAX_QUEUE_SIZE]; +/**/ +sigset_t signal_mask_queue[MAX_QUEUE_SIZE]; + +/* This is only used on machines that don't understand signal sets. * + * On SYSV machines this will represent the signals that are blocked * + * (held) using sighold. On machines which can't block signals at * + * all, we will simulate this by ignoring them and remembering them * + * in this variable. */ +#if !defined(POSIX_SIGNALS) && !defined(BSD_SIGNALS) +static sigset_t blocked_set; +#endif + +#ifdef POSIX_SIGNALS +# define signal_jmp_buf sigjmp_buf +# define signal_setjmp(b) sigsetjmp((b),1) +# define signal_longjmp(b,n) siglongjmp((b),(n)) +#else +# define signal_jmp_buf jmp_buf +# define signal_setjmp(b) setjmp(b) +# define signal_longjmp(b,n) longjmp((b),(n)) +#endif + +#ifdef NO_SIGNAL_BLOCKING +# define signal_process(sig) signal_ignore(sig) +# define signal_reset(sig) install_handler(sig) +#else +# define signal_process(sig) ; +# define signal_reset(sig) ; +#endif + +/* Install signal handler for given signal. * + * If possible, we want to make sure that interrupted * + * system calls are not restarted. */ + +/**/ +void +install_handler(int sig) +{ +#ifdef POSIX_SIGNALS + struct sigaction act; + + act.sa_handler = (SIGNAL_HANDTYPE) handler; + sigemptyset(&act.sa_mask); /* only block sig while in handler */ + act.sa_flags = 0; +# ifdef SA_INTERRUPT /* SunOS 4.x */ + if (interact) + act.sa_flags |= SA_INTERRUPT; /* make sure system calls are not restarted */ +# endif + sigaction(sig, &act, (struct sigaction *)NULL); +#else +# ifdef BSD_SIGNALS + struct sigvec vec; + + vec.sv_handler = (SIGNAL_HANDTYPE) handler; + vec.sv_mask = sigmask(sig); /* mask out this signal while in handler */ +# ifdef SV_INTERRUPT + vec.sv_flags = SV_INTERRUPT; /* make sure system calls are not restarted */ +# endif + sigvec(sig, &vec, (struct sigvec *)NULL); +# else +# ifdef SYSV_SIGNALS + /* we want sigset rather than signal because it will * + * block sig while in handler. signal usually doesn't */ + sigset(sig, handler); +# else /* NO_SIGNAL_BLOCKING (bummer) */ + signal(sig, handler); + +# endif /* SYSV_SIGNALS */ +# endif /* BSD_SIGNALS */ +#endif /* POSIX_SIGNALS */ +} + +/* enable ^C interrupts */ + +/**/ +void +intr(void) +{ + if (interact) + install_handler(SIGINT); +} + +#if 0 +/* disable ^C interrupts */ + +/**/ +void +nointr(void) +{ + if (interact) + signal_ignore(SIGINT); +} +#endif + +/* temporarily block ^C interrupts */ + +/**/ +void +holdintr(void) +{ + if (interact) + signal_block(signal_mask(SIGINT)); +} + +/* release ^C interrupts */ + +/**/ +void +noholdintr(void) +{ + if (interact) + signal_unblock(signal_mask(SIGINT)); +} + +/* create a signal mask containing * + * only the given signal */ + +/**/ +sigset_t +signal_mask(int sig) +{ + sigset_t set; + + sigemptyset(&set); + if (sig) + sigaddset(&set, sig); + return set; +} + +/* Block the signals in the given signal * + * set. Return the old signal set. */ + +/**/ +sigset_t +signal_block(sigset_t set) +{ + sigset_t oset; + +#ifdef POSIX_SIGNALS + sigprocmask(SIG_BLOCK, &set, &oset); +#else +# ifdef BSD_SIGNALS + oset = sigblock(set); +# else +# ifdef SYSV_SIGNALS + int i; + + oset = blocked_set; + for (i = 1; i <= NSIG; ++i) { + if (sigismember(&set, i) && !sigismember(&blocked_set, i)) { + sigaddset(&blocked_set, i); + sighold(i); + } + } +# else /* NO_SIGNAL_BLOCKING */ +/* We will just ignore signals if the system doesn't have * + * the ability to block them. */ + int i; + + oset = blocked_set; + for (i = 1; i <= NSIG; ++i) { + if (sigismember(&set, i) && !sigismember(&blocked_set, i)) { + sigaddset(&blocked_set, i); + signal_ignore(i); + } + } +# endif /* SYSV_SIGNALS */ +# endif /* BSD_SIGNALS */ +#endif /* POSIX_SIGNALS */ + + return oset; +} + +/* Unblock the signals in the given signal * + * set. Return the old signal set. */ + +/**/ +sigset_t +signal_unblock(sigset_t set) +{ + sigset_t oset; + +#ifdef POSIX_SIGNALS + sigprocmask(SIG_UNBLOCK, &set, &oset); +#else +# ifdef BSD_SIGNALS + sigfillset(&oset); + oset = sigsetmask(oset); + sigsetmask(oset & ~set); +# else +# ifdef SYSV_SIGNALS + int i; + + oset = blocked_set; + for (i = 1; i <= NSIG; ++i) { + if (sigismember(&set, i) && sigismember(&blocked_set, i)) { + sigdelset(&blocked_set, i); + sigrelse(i); + } + } +# else /* NO_SIGNAL_BLOCKING */ +/* On systems that can't block signals, we are just ignoring them. So * + * to unblock signals, we just reenable the signal handler for them. */ + int i; + + oset = blocked_set; + for (i = 1; i <= NSIG; ++i) { + if (sigismember(&set, i) && sigismember(&blocked_set, i)) { + sigdelset(&blocked_set, i); + install_handler(i); + } + } +# endif /* SYSV_SIGNALS */ +# endif /* BSD_SIGNALS */ +#endif /* POSIX_SIGNALS */ + + return oset; +} + +/* set the process signal mask to * + * be the given signal mask */ + +/**/ +sigset_t +signal_setmask(sigset_t set) +{ + sigset_t oset; + +#ifdef POSIX_SIGNALS + sigprocmask(SIG_SETMASK, &set, &oset); +#else +# ifdef BSD_SIGNALS + oset = sigsetmask(set); +# else +# ifdef SYSV_SIGNALS + int i; + + oset = blocked_set; + for (i = 1; i <= NSIG; ++i) { + if (sigismember(&set, i) && !sigismember(&blocked_set, i)) { + sigaddset(&blocked_set, i); + sighold(i); + } else if (!sigismember(&set, i) && sigismember(&blocked_set, i)) { + sigdelset(&blocked_set, i); + sigrelse(i); + } + } +# else /* NO_SIGNAL_BLOCKING */ + int i; + + oset = blocked_set; + for (i = 1; i < NSIG; ++i) { + if (sigismember(&set, i) && !sigismember(&blocked_set, i)) { + sigaddset(&blocked_set, i); + signal_ignore(i); + } else if (!sigismember(&set, i) && sigismember(&blocked_set, i)) { + sigdelset(&blocked_set, i); + install_handler(i); + } + } +# endif /* SYSV_SIGNALS */ +# endif /* BSD_SIGNALS */ +#endif /* POSIX_SIGNALS */ + + return oset; +} + +#if defined(NO_SIGNAL_BLOCKING) +static int suspend_longjmp = 0; +static signal_jmp_buf suspend_jmp_buf; +#endif + +/**/ +int +signal_suspend(int sig, int sig2) +{ + int ret; + +#ifdef POSIX_SIGNALS + sigset_t set; + + sigfillset(&set); + sigdelset(&set, sig); + sigdelset(&set, SIGHUP); /* still don't know why we add this? */ + if (sig2) + sigdelset(&set, sig2); + ret = sigsuspend(&set); +#else +# ifdef BSD_SIGNALS + sigset_t set; + + sigfillset(&set); + sigdelset(&set, sig); + if (sig2) + sigdelset(&set, sig2); + ret = sigpause(set); +# else +# ifdef SYSV_SIGNALS + ret = sigpause(sig); + +# else /* NO_SIGNAL_BLOCKING */ + /* need to use signal_longjmp to make this race-free * + * between the child_unblock() and pause() */ + if (signal_setjmp(suspend_jmp_buf) == 0) { + suspend_longjmp = 1; /* we want to signal_longjmp after catching signal */ + child_unblock(); /* do we need to unblock sig2 as well? */ + ret = pause(); + } + suspend_longjmp = 0; /* turn off using signal_longjmp since we are past * + * the pause() function. */ +# endif /* SYSV_SIGNALS */ +# endif /* BSD_SIGNALS */ +#endif /* POSIX_SIGNALS */ + + return ret; +} + +/* What flavor of waitpid/wait3/wait shall we use? */ + +#ifdef HAVE_WAITPID +# define WAIT(pid, statusp, options) waitpid(pid, statusp, options) +#else +# ifdef HAVE_WAIT3 +# define WAIT(pid, statusp, options) wait3((void *) statusp, options, NULL) +# else +# define WAIT(pid, statusp, options) wait(statusp) +# endif +#endif + +/* the signal handler */ + +/**/ +RETSIGTYPE +handler(int sig) +{ + sigset_t newmask, oldmask; + +#if defined(NO_SIGNAL_BLOCKING) + int do_jump; + signal_jmp_buf jump_to; +#endif + + signal_process(sig); + + sigfillset(&newmask); + oldmask = signal_block(newmask); /* Block all signals temporarily */ + +#if defined(NO_SIGNAL_BLOCKING) + do_jump = suspend_longjmp; /* do we need to longjmp to signal_suspend */ + suspend_longjmp = 0; /* In case a SIGCHLD somehow arrives */ + + if (sig == SIGCHLD) { /* Traps can cause nested child_suspend() */ + if (do_jump) + jump_to = suspend_jmp_buf; /* Copy suspend_jmp_buf */ + } +#endif + + if (queueing_enabled) { /* Are we queueing signals now? */ + int temp_rear = ++queue_rear % MAX_QUEUE_SIZE; + + DPUTS(temp_rear == queue_front, "BUG: signal queue full"); + if (temp_rear != queue_front) { /* Make sure it's not full (extremely unlikely) */ + queue_rear = temp_rear; /* ok, not full, so add to queue */ + signal_queue[queue_rear] = sig; /* save signal caught */ + signal_mask_queue[queue_rear] = oldmask; /* save current signal mask */ + } + signal_reset(sig); + return; + } + + signal_setmask(oldmask); /* Reset signal mask, signal traps ok now */ + + switch (sig) { + case SIGCHLD: + + /* keep WAITING until no more child processes to reap */ + for (;;) + cont: { + int old_errno = errno; /* save the errno, since WAIT may change it */ + int status; + Job jn; + Process pn; + pid_t pid; + pid_t *procsubpid = &cmdoutpid; + int *procsubval = &cmdoutval; + struct execstack *es = exstack; + + pid = WAIT(-1, &status, WNOHANG|WUNTRACED); /* reap the child process */ + + if (!pid) /* no more children to reap */ + break; + + /* check if child returned was from process substitution */ + for (;;) { + if (pid == *procsubpid) { + *procsubpid = 0; + if (WIFSIGNALED(status)) + *procsubval = (0200 | WTERMSIG(status)); + else + *procsubval = WEXITSTATUS(status); + times(&shtms); + goto cont; + } + if (!es) + break; + procsubpid = &es->cmdoutpid; + procsubval = &es->cmdoutval; + es = es->next; + } + + /* check for WAIT error */ + if (pid == -1) { + if (errno != ECHILD) + zerr("wait failed: %e", NULL, errno); + errno = old_errno; /* WAIT changed errno, so restore the original */ + break; + } + + /* Find the process and job containing this pid and update it. */ + if (findproc(pid, &jn, &pn)) { + update_process(pn, status); + update_job(jn); + } else { + /* If not found, update the shell record of time spent by + * children in sub processes anyway: otherwise, this + * will get added on to the next found process that terminates. + */ + times(&shtms); + } + } + break; + + case SIGHUP: + if (sigtrapped[SIGHUP]) + dotrap(SIGHUP); + else { + stopmsg = 1; + zexit(SIGHUP, 1); + } + break; + + case SIGINT: + if (sigtrapped[SIGINT]) + dotrap(SIGINT); + else { + if ((isset(PRIVILEGED) || isset(RESTRICTED)) && + isset(INTERACTIVE) && noerrexit < 0) + zexit(SIGINT, 1); + if (list_pipe || chline || simple_pline) { + breaks = loops; + errflag = 1; + inerrflush(); + } + } + break; + +#ifdef SIGWINCH + case SIGWINCH: + adjustwinsize(); /* check window size and adjust */ + if (sigtrapped[SIGWINCH]) + dotrap(SIGWINCH); + break; +#endif + + case SIGALRM: + if (sigtrapped[SIGALRM]) { + int tmout; + dotrap(SIGALRM); + if ((tmout = getiparam("TMOUT"))) + alarm(tmout); /* reset the alarm */ + } else { + int idle = ttyidlegetfn(NULL); + int tmout = getiparam("TMOUT"); + if (idle >= 0 && idle < tmout) + alarm(tmout - idle); + else { + errflag = noerrs = 0; + zerr("timeout", NULL, 0); + errflag = 0; + stopmsg = 1; + zexit(SIGALRM, 1); + } + } + break; + + default: + dotrap(sig); + break; + } /* end of switch(sig) */ + + signal_reset(sig); + +/* This is used to make signal_suspend() race-free */ +#if defined(NO_SIGNAL_BLOCKING) + if (do_jump) + signal_longjmp(jump_to, 1); +#endif + +} /* handler */ + + +/* SIGHUP any jobs left running */ + +/**/ +void +killrunjobs(int from_signal) +{ + int i, killed = 0; + + if (unset(HUP)) + return; + for (i = 1; i < MAXJOB; i++) + if ((from_signal || i != thisjob) && (jobtab[i].stat & STAT_LOCKED) && + !(jobtab[i].stat & STAT_NOPRINT) && + !(jobtab[i].stat & STAT_STOPPED)) { + if (killpg(jobtab[i].gleader, SIGHUP) != -1) + killed++; + } + if (killed) + zerr("warning: %d jobs SIGHUPed", NULL, killed); +} + + +/* send a signal to a job (simply involves kill if monitoring is on) */ + +/**/ +int +killjb(Job jn, int sig) +{ + Process pn; + int err = 0; + + if (jobbing) { + if (jn->stat & STAT_SUPERJOB) { + if (sig == SIGCONT) { + for (pn = jobtab[jn->other].procs; pn; pn = pn->next) + kill(pn->pid, sig); + + for (pn = jn->procs; pn->next; pn = pn->next) + err = kill(pn->pid, sig); + + return err; + } + + killpg(jobtab[jn->other].gleader, sig); + return killpg(jn->gleader, sig); + } + else + return (killpg(jn->gleader, sig)); + } + for (pn = jn->procs; pn; pn = pn->next) + if ((err = kill(pn->pid, sig)) == -1 && errno != ESRCH) + return -1; + return err; +} + +/**/ +int +settrap(int sig, List l) +{ + if (sig == -1) + return 1; + if (jobbing && (sig == SIGTTOU || sig == SIGTSTP || sig == SIGTTIN)) { + zerr("can't trap SIG%s in interactive shells", sigs[sig], 0); + return 1; + } + if (sigfuncs[sig]) + unsettrap(sig); + sigfuncs[sig] = l; + if (!l) { + sigtrapped[sig] = ZSIG_IGNORED; + if (sig && sig <= SIGCOUNT && +#ifdef SIGWINCH + sig != SIGWINCH && +#endif + sig != SIGCHLD) + signal_ignore(sig); + } else { + sigtrapped[sig] = ZSIG_TRAPPED; + if (sig && sig <= SIGCOUNT && +#ifdef SIGWINCH + sig != SIGWINCH && +#endif + sig != SIGCHLD) + install_handler(sig); + } + return 0; +} + +/**/ +void +unsettrap(int sig) +{ + int trapped; + + if (sig == -1 || !(trapped = sigtrapped[sig]) || + (jobbing && (sig == SIGTTOU || sig == SIGTSTP || sig == SIGTTIN))) { + return; + } + sigtrapped[sig] = 0; + if (sig == SIGINT && interact) { + /* PWS 1995/05/16: added test for interactive, also noholdintr() * + * as subshells ignoring SIGINT have it blocked from delivery */ + intr(); + noholdintr(); + } else if (sig == SIGHUP) + install_handler(sig); + else if (sig && sig <= SIGCOUNT && +#ifdef SIGWINCH + sig != SIGWINCH && +#endif + sig != SIGCHLD) + signal_default(sig); + if (trapped & ZSIG_FUNC) { + char func[20]; + HashNode hn; + + sprintf(func, "TRAP%s", sigs[sig]); + if ((hn = shfunctab->removenode(shfunctab, func))) + shfunctab->freenode(hn); + } else if (sigfuncs[sig]) { + freestruct(sigfuncs[sig]); + sigfuncs[sig] = NULL; + } +} + +/* Execute a trap function for a given signal, possibly + * with non-standard sigtrapped & sigfuncs values + */ + +/**/ +void +dotrapargs(int sig, int *sigtr, void *sigfn) +{ + LinkList args; + char *name, num[4]; + int trapret = 0; + int obreaks = breaks; + + /* if signal is being ignored or the trap function * + * is NULL, then return * + * * + * Also return if errflag is set. In fact, the code in the * + * function will test for this, but this way we keep status flags * + * intact without working too hard. Special cases (e.g. calling * + * a trap for SIGINT after the error flag was set) are handled * + * by the calling code. (PWS 1995/06/08). */ + if ((*sigtr & ZSIG_IGNORED) || !sigfn || errflag) + return; + + *sigtr |= ZSIG_IGNORED; + + lexsave(); + execsave(); + breaks = 0; + if (*sigtr & ZSIG_FUNC) { + PERMALLOC { + args = newlinklist(); + name = (char *) zalloc(5 + strlen(sigs[sig])); + sprintf(name, "TRAP%s", sigs[sig]); + addlinknode(args, name); + sprintf(num, "%d", sig); + addlinknode(args, num); + } LASTALLOC; + trapreturn = -1; + doshfunc(sigfn, args, 0, 1); + freelinklist(args, (FreeFunc) NULL); + zsfree(name); + } else HEAPALLOC { + execlist(dupstruct(sigfn), 1, 0); + } LASTALLOC; + if (trapreturn > 0) + trapret = trapreturn; + else if (errflag) + trapret = 1; + execrestore(); + lexrestore(); + + if (trapret > 0) { + breaks = loops; + errflag = 1; + } else { + breaks += obreaks; + if (breaks > loops) + breaks = loops; + } + + if (*sigtr != ZSIG_IGNORED) + *sigtr &= ~ZSIG_IGNORED; +} + +/* Standard call to execute a trap for a given signal */ + +/**/ +void +dotrap(int sig) +{ + dotrapargs(sig, sigtrapped+sig, sigfuncs[sig]); +} |