openenvutils/commandshell/shell/src/signals.c
changeset 0 2e3d3ce01487
child 1 0fdb7f6b0309
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/openenvutils/commandshell/shell/src/signals.c	Tue Feb 02 10:12:00 2010 +0200
@@ -0,0 +1,1133 @@
+// signals.c - signals handling code
+//
+// © Portions Copyright (c) Symbian Software Ltd 2007. All rights reserved.
+//
+/*
+ * 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"
+
+#ifdef __SYMBIAN32__
+#include "dummy.h"
+#endif //__SYMBIAN32__
+
+#ifdef __SYMBIAN32__
+#ifdef __WINSCW__
+#pragma warn_unusedarg off
+#endif//__WINSCW__
+#endif//__SYMBIAN32__
+
+/* Array describing the state of each signal: an element contains *
+ * 0 for the default action or some ZSIG_* flags ored together.   */
+
+/**/
+mod_export int sigtrapped[VSIGCOUNT];
+
+/* trap functions for each signal */
+
+/**/
+mod_export Eprog sigfuncs[VSIGCOUNT];
+
+/* Total count of trapped signals */
+
+/**/
+mod_export int nsigtrapped;
+
+/* Variables used by signal queueing */
+
+/**/
+mod_export int queueing_enabled, queue_front, queue_rear;
+/**/
+mod_export int signal_queue[MAX_QUEUE_SIZE];
+/**/
+mod_export sigset_t signal_mask_queue[MAX_QUEUE_SIZE];
+
+/* Variables used by trap queueing */
+
+/**/
+mod_export int trap_queueing_enabled, trap_queue_front, trap_queue_rear;
+/**/
+mod_export int trap_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.                    */
+
+/**/
+mod_export void
+install_handler(int sig)
+{
+#ifdef POSIX_SIGNALS
+    struct sigaction act;
+ 
+    act.sa_handler = (SIGNAL_HANDTYPE) zhandler;
+    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
+#ifndef __SYMBIAN32__
+    sigaction(sig, &act, (struct sigaction *)NULL);
+#endif    
+#else
+# ifdef BSD_SIGNALS
+    struct sigvec vec;
+ 
+    vec.sv_handler = (SIGNAL_HANDTYPE) zhandler;
+    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, zhandler);
+#  else  /* NO_SIGNAL_BLOCKING (bummer) */
+#ifndef __SYMBIAN32__
+    signal(sig, zhandler); 
+#endif
+
+#  endif /* SYSV_SIGNALS  */
+# endif  /* BSD_SIGNALS   */
+#endif   /* POSIX_SIGNALS */
+}
+
+/* enable ^C interrupts */
+ 
+/**/
+mod_export void
+intr(void)
+{
+    if (interact)
+        install_handler(SIGINT);
+}
+
+/* disable ^C interrupts */
+ 
+#if 0 /**/
+void
+nointr(void)
+{
+    if (interact)
+        signal_ignore(SIGINT);
+}
+#endif
+ 
+/* temporarily block ^C interrupts */
+ 
+/**/
+mod_export void
+holdintr(void)
+{
+    if (interact)
+        signal_block(signal_mask(SIGINT));
+}
+
+/* release ^C interrupts */
+ 
+/**/
+mod_export 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.       */
+
+/**/
+#ifdef POSIX_SIGNALS
+
+/**/
+mod_export sigset_t dummy_sigset1, dummy_sigset2;
+
+/**/
+#else
+
+/**/
+#ifndef BSD_SIGNALS
+
+sigset_t
+signal_block(sigset_t set)
+{
+    sigset_t oset;
+ 
+#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  */
+ 
+    return oset;
+}
+
+/**/
+#endif /* BSD_SIGNALS */
+
+/**/
+#endif /* POSIX_SIGNALS */
+
+/* Unblock the signals in the given signal *
+ * set. Return the old signal set.         */
+
+#ifndef POSIX_SIGNALS
+
+sigset_t
+signal_unblock(sigset_t set)
+{
+
+    sigset_t oset;
+    
+#ifndef __SYMBIAN32__
+# 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 //__SYMBIAN32__
+    return oset;
+}
+
+#endif   /* POSIX_SIGNALS */
+
+/* set the process signal mask to *
+ * be the given signal mask       */
+
+/**/
+mod_export sigset_t
+signal_setmask(sigset_t set)
+{
+    sigset_t oset;
+ 
+#ifdef POSIX_SIGNALS
+    sigprocmask(35, &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;
+#ifdef BROKEN_POSIX_SIGSUSPEND
+    sigset_t oset;
+#endif /* BROKEN_POSIX_SIGSUSPEND */
+
+    if (isset(TRAPSASYNC)) {
+	sigemptyset(&set);
+    } else {
+	sigfillset(&set);
+	sigdelset(&set, sig);
+	sigdelset(&set, SIGHUP);  /* still don't know why we add this? */
+	if (sig2)
+	    sigdelset(&set, sig2);
+    }
+#ifdef BROKEN_POSIX_SIGSUSPEND
+    sigprocmask(SIG_SETMASK, &set, &oset);
+    pause();
+    sigprocmask(SIG_SETMASK, &oset, NULL);
+#else /* not BROKEN_POSIX_SIGSUSPEND */
+    ret = sigsuspend(&set);
+#endif /* BROKEN_POSIX_SIGSUSPEND */
+#else /* not POSIX_SIGNALS */
+# ifdef BSD_SIGNALS
+    sigset_t set;
+
+    if (isset(TRAPSASYNC)) {
+	sigemptyset(&set);
+    } else {
+	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;
+}
+
+/* the signal handler */
+ 
+/**/
+mod_export RETSIGTYPE
+zhandler(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 signal_suspend()  */
+        if (do_jump)
+            jump_to = suspend_jmp_buf;      /* Copy suspend_jmp_buf                    */
+    }
+#endif
+
+    /* Are we queueing signals now?      */
+    if (queueing_enabled) {
+        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;
+
+	    /*
+	     * Reap the child process.
+	     * If we want usage information, we need to use wait3.
+	     */
+#ifdef HAVE_WAIT3
+# ifdef HAVE_GETRUSAGE
+	    struct rusage ru;
+
+	    pid = wait3((void *)&status, WNOHANG|WUNTRACED, &ru); 
+# else
+	    pid = wait3((void *)&status, WNOHANG|WUNTRACED, NULL);
+# endif
+#else
+# ifdef HAVE_WAITPID
+	    pid = waitpid(-1, &status, WNOHANG|WUNTRACED);
+# else
+	    pid = wait(&status);
+# endif
+#endif
+
+            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);
+		    get_usage();
+		    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, 0)) {
+#if defined(HAVE_WAIT3) && defined(HAVE_GETRUSAGE) 
+		struct timezone dummy_tz;
+		gettimeofday(&pn->endtime, &dummy_tz);
+		pn->status = status;
+		pn->ti = ru;
+#elif !defined(HAVE_GETRUSAGE)
+		update_process(pn, status);
+#endif
+		update_job(jn);
+	    } else if (findproc(pid, &jn, &pn, 1)) {
+		pn->status = 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.
+		 */
+		get_usage();
+	    }
+        }
+        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(1);  /* 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;
+		zwarn("timeout", NULL, 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 (jobtab[i].gleader != getpid() &&
+		killpg(jobtab[i].gleader, SIGHUP) != -1)
+                killed++;
+        }
+    if (killed)
+        zwarn("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)
+                    if (killpg(pn->pid, sig) == -1)
+			if (kill(pn->pid, sig) == -1 && errno != ESRCH)
+			    err = -1;
+ 
+                for (pn = jn->procs; pn->next; pn = pn->next)
+                    if (kill(pn->pid, sig) == -1 && errno != ESRCH)
+			err = -1;
+
+		if (!jobtab[jn->other].procs && pn)
+		    if (kill(pn->pid, sig) == -1 && errno != ESRCH)
+			err = -1;
+
+                return err;
+            }
+            if (killpg(jobtab[jn->other].gleader, sig) == -1 && errno != ESRCH)
+		err = -1;
+		
+	    if (killpg(jn->gleader, sig) == -1 && errno != ESRCH)
+		err = -1;
+
+	    return err;
+        }
+        else
+	    return killpg(jn->gleader, sig);
+    }
+    for (pn = jn->procs; pn; pn = pn->next)
+        if ((err = kill(pn->pid, sig)) == -1 && errno != ESRCH && sig != 0)
+            return -1;
+    return err;
+}
+
+/*
+ * List for saving traps.  We don't usually have that many traps
+ * at once, so just use a linked list.
+ */
+struct savetrap {
+    int sig, flags, local;
+    void *list;
+};
+
+static LinkList savetraps;
+static int dontsavetrap;
+
+/*
+ * Save the current trap by copying it.  This does nothing to
+ * the existing value of sigtrapped or sigfuncs.
+ */
+
+static void
+dosavetrap(int sig, int level)
+{
+    struct savetrap *st;
+    st = (struct savetrap *)zalloc(sizeof(*st));
+    st->sig = sig;
+    st->local = level;
+    if ((st->flags = sigtrapped[sig]) & ZSIG_FUNC) {
+	/*
+	 * Get the old function: this assumes we haven't added
+	 * the new one yet.
+	 */
+	Shfunc shf, newshf = NULL;
+	if ((shf = (Shfunc)gettrapnode(sig, 1))) {
+	    /* Copy the node for saving */
+	    newshf = (Shfunc) zalloc(sizeof(*newshf));
+	    newshf->nam = ztrdup(shf->nam);
+	    newshf->flags = shf->flags;
+	    newshf->funcdef = dupeprog(shf->funcdef, 0);
+	    if (shf->flags & PM_UNDEFINED)
+		newshf->funcdef->shf = newshf;
+	}
+#ifdef DEBUG
+	else dputs("BUG: no function present with function trap flag set.");
+#endif
+	st->list = newshf;
+    } else if (sigtrapped[sig]) {
+	st->list = sigfuncs[sig] ? dupeprog(sigfuncs[sig], 0) : NULL;
+    } else {
+	DPUTS(sigfuncs[sig], "BUG: sigfuncs not null for untrapped signal");
+	st->list = NULL;
+    }
+    if (!savetraps)
+	savetraps = znewlinklist();
+    /*
+     * Put this at the front of the list
+     */
+    zinsertlinknode(savetraps, (LinkNode)savetraps, st);
+}
+
+/**/
+mod_export int
+settrap(int sig, Eprog 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;
+    }
+
+    /*
+     * Call unsettrap() unconditionally, to make sure trap is saved
+     * if necessary.
+     */
+    queue_signals();
+    unsettrap(sig);
+
+    sigfuncs[sig] = l;
+    if (empty_eprog(l)) {
+	sigtrapped[sig] = ZSIG_IGNORED;
+        if (sig && sig <= SIGCOUNT &&
+#ifdef SIGWINCH
+            sig != SIGWINCH &&
+#endif
+            sig != SIGCHLD)
+            signal_ignore(sig);
+    } else {
+	nsigtrapped++;
+        sigtrapped[sig] = ZSIG_TRAPPED;
+        if (sig && sig <= SIGCOUNT &&
+#ifdef SIGWINCH
+            sig != SIGWINCH &&
+#endif
+            sig != SIGCHLD)
+            install_handler(sig);
+    }
+    /*
+     * Note that introducing the locallevel does not affect whether
+     * sigtrapped[sig] is zero or not, i.e. a test without a mask
+     * works just the same.
+     */
+    sigtrapped[sig] |= (locallevel << ZSIG_SHIFT);
+    unqueue_signals();
+    return 0;
+}
+
+/**/
+void
+unsettrap(int sig)
+{
+    HashNode hn;
+
+    queue_signals();
+    hn = removetrap(sig);
+    if (hn)
+	shfunctab->freenode(hn);
+    unqueue_signals();
+}
+
+/**/
+HashNode
+removetrap(int sig)
+{
+    int trapped;
+
+    if (sig == -1 ||
+	(jobbing && (sig == SIGTTOU || sig == SIGTSTP || sig == SIGTTIN)))
+	return NULL;
+
+    queue_signals();
+    trapped = sigtrapped[sig];
+    /*
+     * Note that we save the trap here even if there isn't an existing
+     * one, to aid in removing this one.  However, if there's
+     * already one at the current locallevel we just overwrite it.
+     */
+    if (!dontsavetrap && (isset(LOCALTRAPS) || sig == SIGEXIT) &&
+	locallevel &&
+	(!trapped || locallevel > (sigtrapped[sig] >> ZSIG_SHIFT)))
+	dosavetrap(sig, locallevel);
+
+    if (!trapped) {
+	unqueue_signals();
+        return NULL;
+    }
+    if (sigtrapped[sig] & ZSIG_TRAPPED)
+	nsigtrapped--;
+    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);
+
+    /*
+     * At this point we free the appropriate structs.  If we don't
+     * want that to happen then either the function should already have been
+     * removed from shfunctab, or the entry in sigfuncs should have been set
+     * to NULL.  This is no longer necessary for saving traps as that
+     * copies the structures, so here we are remove the originals.
+     * That causes a little inefficiency, but a good deal more reliability.
+     */
+    if (trapped & ZSIG_FUNC) {
+	HashNode node = gettrapnode(sig, 1);
+
+	/*
+	 * As in dosavetrap(), don't call removeshfuncnode() because
+	 * that calls back into unsettrap();
+	 */
+	sigfuncs[sig] = NULL;
+	if (node)
+	    removehashnode(shfunctab, node->nam);
+	unqueue_signals();
+
+	return node;
+    } else if (sigfuncs[sig]) {
+	freeeprog(sigfuncs[sig]);
+	sigfuncs[sig] = NULL;
+    }
+    unqueue_signals();
+
+    return NULL;
+}
+
+/**/
+void
+starttrapscope(void)
+{
+    /* No special SIGEXIT behaviour inside another trap. */
+    if (intrap)
+	return;
+
+    /*
+     * SIGEXIT needs to be restored at the current locallevel,
+     * so give it the next higher one. dosavetrap() is called
+     * automatically where necessary.
+     */
+    if (sigtrapped[SIGEXIT]) {
+	locallevel++;
+	unsettrap(SIGEXIT);
+	locallevel--;
+    }
+}
+
+/*
+ * Reset traps after the end of a function: must be called after
+ * endparamscope() so that the locallevel has been decremented.
+ */
+
+/**/
+void
+endtrapscope(void)
+{
+    LinkNode ln;
+    struct savetrap *st;
+    int exittr;
+    void *exitfn = NULL;
+
+    /*
+     * Remember the exit trap, but don't run it until
+     * after all the other traps have been put back.
+     * Don't do this inside another trap.
+     */
+    if (intrap)
+	exittr = 0;
+    else if ((exittr = sigtrapped[SIGEXIT])) {
+	if (exittr & ZSIG_FUNC) {
+	    exitfn = removehashnode(shfunctab, "TRAPEXIT");
+	} else {
+	    exitfn = sigfuncs[SIGEXIT];
+	}
+	sigfuncs[SIGEXIT] = NULL;
+	if (sigtrapped[SIGEXIT] & ZSIG_TRAPPED)
+	    nsigtrapped--;
+	sigtrapped[SIGEXIT] = 0;
+    }
+
+    if (savetraps) {
+	while ((ln = firstnode(savetraps)) &&
+	       (st = (struct savetrap *) ln->dat) &&
+	       st->local > locallevel) {
+	    int sig = st->sig;
+
+	    remnode(savetraps, ln);
+
+	    if (st->flags && (st->list != NULL)) {
+		Eprog prog = (st->flags & ZSIG_FUNC) ?
+		    ((Shfunc) st->list)->funcdef : (Eprog) st->list;
+		/* prevent settrap from saving this */
+		dontsavetrap++;
+		settrap(sig, prog);
+		dontsavetrap--;
+		/*
+		 * counting of nsigtrapped should presumably be handled
+		 * in settrap...
+		 */
+		DPUTS((sigtrapped[sig] ^ st->flags) & ZSIG_TRAPPED,
+		      "BUG: settrap didn't restore correct ZSIG_TRAPPED");
+		if ((sigtrapped[sig] = st->flags) & ZSIG_FUNC)
+		    shfunctab->addnode(shfunctab, ((Shfunc)st->list)->nam,
+				       (Shfunc) st->list);
+	    } else if (sigtrapped[sig])
+		unsettrap(sig);
+
+	    zfree(st, sizeof(*st));
+	}
+    }
+
+    if (exittr) {
+	dotrapargs(SIGEXIT, &exittr, (exittr & ZSIG_FUNC) ?
+		   ((Shfunc)exitfn)->funcdef : (Eprog) exitfn);
+	if (exittr & ZSIG_FUNC)
+	    shfunctab->freenode((HashNode)exitfn);
+	else
+	    freeeprog(exitfn);
+    }
+    DPUTS(!locallevel && savetraps && firstnode(savetraps),
+	  "BUG: still saved traps outside all function scope");
+}
+
+/* Execute a trap function for a given signal, possibly
+ * with non-standard sigtrapped & sigfuncs values
+ */
+
+/* Are we already executing a trap? */
+/**/
+int intrap;
+
+/* Is the current trap a function? */
+
+/**/
+int trapisfunc;
+
+/**/
+void
+dotrapargs(int sig, int *sigtr, void *sigfn)
+{
+    LinkList args;
+    char *name, num[4];
+    int trapret = 0;
+    int obreaks = breaks;
+    int isfunc;
+
+    /* 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).			      *
+     *                                                                *
+     * This test is now replicated in dotrap().                       */
+    if ((*sigtr & ZSIG_IGNORED) || !sigfn || errflag)
+        return;
+
+    /*
+     * Never execute special (synchronous) traps inside other traps.
+     * This can cause unexpected code execution when more than one
+     * of these is set.
+     *
+     * The down side is that it's harder to debug traps.  I don't think
+     * that's a big issue.
+     */
+    if (intrap) {
+	switch (sig) {
+	case SIGEXIT:
+	case SIGDEBUG:
+	case SIGZERR:
+	    return;
+	}
+    }
+
+    intrap++;
+    *sigtr |= ZSIG_IGNORED;
+
+    lexsave();
+    execsave();
+    breaks = 0;
+    runhookdef(BEFORETRAPHOOK, NULL);
+    if (*sigtr & ZSIG_FUNC) {
+	int osc = sfcontext;
+	HashNode hn = gettrapnode(sig, 0);
+
+	args = znewlinklist();
+	/*
+	 * In case of multiple names, try to get
+	 * a hint of the name in use from the function table.
+	 * In special cases, e.g. EXIT traps, the function
+	 * has already been removed.  Then it's OK to
+	 * use the standard name.
+	 */
+	if (hn) {
+	    name = ztrdup(hn->nam);
+	} else {
+	    name = (char *) zalloc(5 + strlen(sigs[sig]));
+	    sprintf(name, "TRAP%s", sigs[sig]);
+	}
+	zaddlinknode(args, name);
+	sprintf(num, "%d", sig);
+	zaddlinknode(args, num);
+
+	trapreturn = -1;	/* incremented by doshfunc */
+	trapisfunc = isfunc = 1;
+
+	sfcontext = SFC_SIGNAL;
+	doshfunc(name, sigfn, args, 0, 1);
+	sfcontext = osc;
+	freelinklist(args, (FreeFunc) NULL);
+	zsfree(name);
+
+    } else {
+	trapreturn = -2;	/* not incremented, used at current level */
+	trapisfunc = isfunc = 0;
+
+	execode(sigfn, 1, 0);
+    }
+    runhookdef(AFTERTRAPHOOK, NULL);
+
+    if (trapreturn > 0 && isfunc) {
+	/*
+	 * Context was its own function.  We propagate the return
+	 * value specially.  Return value zero means don't do
+	 * anything special, so don't handle it.
+	 */
+	trapret = trapreturn;
+    } else if (trapreturn >= 0 && !isfunc) {
+	/*
+	 * Context was an inline trap.  If an explicit return value
+	 * was used, we need to set `lastval'.  Otherwise we use the
+	 * value restored by execrestore.  In this case, all return
+	 * values indicate an explicit return from the current function,
+	 * so always handle specially.  trapreturn is always restored by
+	 * execrestore.
+	 */
+	trapret = trapreturn + 1;
+    } else if (errflag)
+	trapret = 1;
+    execrestore();
+    lexrestore();
+
+    if (trapret > 0) {
+	if (isfunc) {
+	    breaks = loops;
+	    errflag = 1;
+	} else {
+	    lastval = trapret-1;
+	}
+    } else {
+	breaks += obreaks;
+	if (breaks > loops)
+	    breaks = loops;
+    }
+
+    /*
+     * If zle was running while the trap was executed, see if we
+     * need to restore the display.
+     */
+    if (zleactive && resetneeded)
+	zrefresh();
+
+    if (*sigtr != ZSIG_IGNORED)
+	*sigtr &= ~ZSIG_IGNORED;
+    intrap--;
+}
+
+/* Standard call to execute a trap for a given signal. */
+
+/**/
+void
+dotrap(int sig)
+{
+    /* Copied from dotrapargs(). */
+    if ((sigtrapped[sig] & ZSIG_IGNORED) || !sigfuncs[sig] || errflag)
+	return;
+
+    dotrapargs(sig, sigtrapped+sig, sigfuncs[sig]);
+}