--- /dev/null
+/*-
+ * Copyright (c) 1991, 1993
+ * The Regents of the University of California. All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Kenneth Almquist.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ * 4. Neither the name of the University nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#ifndef lint
+#if 0
+static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95";
+#endif
+#endif /* not lint */
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <signal.h>
+#include <unistd.h>
+#include <stdlib.h>
+
+#include "shell.h"
+#include "main.h"
+#include "nodes.h" /* for other headers */
+#include "eval.h"
+#include "jobs.h"
+#include "show.h"
+#include "options.h"
+#include "syntax.h"
+#include "output.h"
+#include "memalloc.h"
+#include "error.h"
+#include "trap.h"
+#include "mystring.h"
+#include "builtins.h"
+#include "myhistedit.h"
+
+#ifdef __APPLE__
+#define sys_nsig (NSIG)
+#endif /* __APPLE__ */
+
+/*
+ * Sigmode records the current value of the signal handlers for the various
+ * modes. A value of zero means that the current handler is not known.
+ * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
+ */
+
+#define S_DFL 1 /* default signal handling (SIG_DFL) */
+#define S_CATCH 2 /* signal is caught */
+#define S_IGN 3 /* signal is ignored (SIG_IGN) */
+#define S_HARD_IGN 4 /* signal is ignored permanently */
+#define S_RESET 5 /* temporary - to reset a hard ignored sig */
+
+
+static char sigmode[NSIG]; /* current value of signal */
+volatile sig_atomic_t pendingsig; /* indicates some signal received */
+volatile sig_atomic_t pendingsig_waitcmd; /* indicates wait builtin should be interrupted */
+static int in_dotrap; /* do we execute in a trap handler? */
+static char *volatile trap[NSIG]; /* trap handler commands */
+static volatile sig_atomic_t gotsig[NSIG];
+ /* indicates specified signal received */
+static int ignore_sigchld; /* Used while handling SIGCHLD traps. */
+static int last_trapsig;
+
+static int exiting; /* exitshell() has been called */
+static int exiting_exitstatus; /* value passed to exitshell() */
+
+static int getsigaction(int, sig_t *);
+
+
+/*
+ * Map a string to a signal number.
+ *
+ * Note: the signal number may exceed NSIG.
+ */
+static int
+sigstring_to_signum(char *sig)
+{
+
+ if (is_number(sig)) {
+ int signo;
+
+ signo = atoi(sig);
+ return ((signo >= 0 && signo < NSIG) ? signo : (-1));
+ } else if (strcasecmp(sig, "EXIT") == 0) {
+ return (0);
+ } else {
+ int n;
+
+ if (strncasecmp(sig, "SIG", 3) == 0)
+ sig += 3;
+ for (n = 1; n < sys_nsig; n++)
+ if (sys_signame[n] &&
+ strcasecmp(sys_signame[n], sig) == 0)
+ return (n);
+ }
+ return (-1);
+}
+
+
+/*
+ * Print a list of valid signal names.
+ */
+static void
+printsignals(void)
+{
+ int n, outlen;
+
+ outlen = 0;
+ for (n = 1; n < sys_nsig; n++) {
+ if (sys_signame[n]) {
+ out1fmt("%s", sys_signame[n]);
+ outlen += strlen(sys_signame[n]);
+ } else {
+ out1fmt("%d", n);
+ outlen += 3; /* good enough */
+ }
+ ++outlen;
+ if (outlen > 71 || n == sys_nsig - 1) {
+ out1str("\n");
+ outlen = 0;
+ } else {
+ out1c(' ');
+ }
+ }
+}
+
+
+/*
+ * The trap builtin.
+ */
+int
+trapcmd(int argc __unused, char **argv)
+{
+ char *action;
+ int signo;
+ int errors = 0;
+ int i;
+
+ while ((i = nextopt("l")) != '\0') {
+ switch (i) {
+ case 'l':
+ printsignals();
+ return (0);
+ }
+ }
+ argv = argptr;
+
+ if (*argv == NULL) {
+ for (signo = 0 ; signo < sys_nsig ; signo++) {
+ if (signo < NSIG && trap[signo] != NULL) {
+ out1str("trap -- ");
+ out1qstr(trap[signo]);
+ if (signo == 0) {
+ out1str(" EXIT\n");
+ } else if (sys_signame[signo]) {
+ out1fmt(" %s\n", sys_signame[signo]);
+ } else {
+ out1fmt(" %d\n", signo);
+ }
+ }
+ }
+ return 0;
+ }
+ action = NULL;
+ if (*argv && !is_number(*argv)) {
+ if (strcmp(*argv, "-") == 0)
+ argv++;
+ else {
+ action = *argv;
+ argv++;
+ }
+ }
+ for (; *argv; argv++) {
+ if ((signo = sigstring_to_signum(*argv)) == -1) {
+ warning("bad signal %s", *argv);
+ errors = 1;
+ continue;
+ }
+ INTOFF;
+ if (action)
+ action = savestr(action);
+ if (trap[signo])
+ ckfree(trap[signo]);
+ trap[signo] = action;
+ if (signo != 0)
+ setsignal(signo);
+ INTON;
+ }
+ return errors;
+}
+
+
+/*
+ * Clear traps on a fork.
+ */
+void
+clear_traps(void)
+{
+ char *volatile *tp;
+
+ for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
+ if (*tp && **tp) { /* trap not NULL or SIG_IGN */
+ INTOFF;
+ ckfree(*tp);
+ *tp = NULL;
+ if (tp != &trap[0])
+ setsignal(tp - trap);
+ INTON;
+ }
+ }
+}
+
+
+/*
+ * Check if we have any traps enabled.
+ */
+int
+have_traps(void)
+{
+ char *volatile *tp;
+
+ for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
+ if (*tp && **tp) /* trap not NULL or SIG_IGN */
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * Set the signal handler for the specified signal. The routine figures
+ * out what it should be set to.
+ */
+void
+setsignal(int signo)
+{
+ int action;
+ sig_t sigact = SIG_DFL;
+ struct sigaction sa;
+ char *t;
+
+ if ((t = trap[signo]) == NULL)
+ action = S_DFL;
+ else if (*t != '\0')
+ action = S_CATCH;
+ else
+ action = S_IGN;
+ if (action == S_DFL) {
+ switch (signo) {
+ case SIGINT:
+ action = S_CATCH;
+ break;
+ case SIGQUIT:
+#ifdef DEBUG
+ {
+ extern int debug;
+
+ if (debug)
+ break;
+ }
+#endif
+ action = S_CATCH;
+ break;
+ case SIGTERM:
+ if (rootshell && iflag)
+ action = S_IGN;
+ break;
+#if JOBS
+ case SIGTSTP:
+ case SIGTTOU:
+ if (rootshell && mflag)
+ action = S_IGN;
+ break;
+#endif
+ }
+ }
+
+ t = &sigmode[signo];
+ if (*t == 0) {
+ /*
+ * current setting unknown
+ */
+ if (!getsigaction(signo, &sigact)) {
+ /*
+ * Pretend it worked; maybe we should give a warning
+ * here, but other shells don't. We don't alter
+ * sigmode, so that we retry every time.
+ */
+ return;
+ }
+ if (sigact == SIG_IGN) {
+ if (mflag && (signo == SIGTSTP ||
+ signo == SIGTTIN || signo == SIGTTOU)) {
+ *t = S_IGN; /* don't hard ignore these */
+ } else
+ *t = S_HARD_IGN;
+ } else {
+ *t = S_RESET; /* force to be set */
+ }
+ }
+ if (*t == S_HARD_IGN || *t == action)
+ return;
+ switch (action) {
+ case S_DFL: sigact = SIG_DFL; break;
+ case S_CATCH: sigact = onsig; break;
+ case S_IGN: sigact = SIG_IGN; break;
+ }
+ *t = action;
+ sa.sa_handler = sigact;
+ sa.sa_flags = 0;
+ sigemptyset(&sa.sa_mask);
+ sigaction(signo, &sa, NULL);
+}
+
+
+/*
+ * Return the current setting for sig w/o changing it.
+ */
+static int
+getsigaction(int signo, sig_t *sigact)
+{
+ struct sigaction sa;
+
+ if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
+ return 0;
+ *sigact = (sig_t) sa.sa_handler;
+ return 1;
+}
+
+
+/*
+ * Ignore a signal.
+ */
+void
+ignoresig(int signo)
+{
+
+ if (sigmode[signo] == 0)
+ setsignal(signo);
+ if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
+ signal(signo, SIG_IGN);
+ sigmode[signo] = S_IGN;
+ }
+}
+
+
+int
+issigchldtrapped(void)
+{
+
+ return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0');
+}
+
+
+/*
+ * Signal handler.
+ */
+void
+onsig(int signo)
+{
+
+ if (signo == SIGINT && trap[SIGINT] == NULL) {
+ /*
+ * The !in_dotrap here is safe. The only way we can arrive
+ * here with in_dotrap set is that a trap handler set SIGINT to
+ * SIG_DFL and killed itself.
+ */
+ if (suppressint && !in_dotrap)
+ SET_PENDING_INT;
+ else
+ onint();
+ return;
+ }
+
+ /* If we are currently in a wait builtin, prepare to break it */
+ if (signo == SIGINT || signo == SIGQUIT)
+ pendingsig_waitcmd = signo;
+
+ if (trap[signo] != NULL && trap[signo][0] != '\0' &&
+ (signo != SIGCHLD || !ignore_sigchld)) {
+ gotsig[signo] = 1;
+ pendingsig = signo;
+ pendingsig_waitcmd = signo;
+ }
+}
+
+
+/*
+ * Called to execute a trap. Perhaps we should avoid entering new trap
+ * handlers while we are executing a trap handler.
+ */
+void
+dotrap(void)
+{
+ int i;
+ int savestatus, prev_evalskip, prev_skipcount;
+
+ in_dotrap++;
+ for (;;) {
+ pendingsig = 0;
+ pendingsig_waitcmd = 0;
+ for (i = 1; i < NSIG; i++) {
+ if (gotsig[i]) {
+ gotsig[i] = 0;
+ if (trap[i]) {
+ /*
+ * Ignore SIGCHLD to avoid infinite
+ * recursion if the trap action does
+ * a fork.
+ */
+ if (i == SIGCHLD)
+ ignore_sigchld++;
+
+ /*
+ * Backup current evalskip
+ * state and reset it before
+ * executing a trap, so that the
+ * trap is not disturbed by an
+ * ongoing break/continue/return
+ * statement.
+ */
+ prev_evalskip = evalskip;
+ prev_skipcount = skipcount;
+ evalskip = 0;
+
+ last_trapsig = i;
+ savestatus = exitstatus;
+ evalstring(trap[i], 0);
+
+ /*
+ * If such a command was not
+ * already in progress, allow a
+ * break/continue/return in the
+ * trap action to have an effect
+ * outside of it.
+ */
+ if (evalskip == 0 ||
+ prev_evalskip != 0) {
+ evalskip = prev_evalskip;
+ skipcount = prev_skipcount;
+ exitstatus = savestatus;
+ }
+
+ if (i == SIGCHLD)
+ ignore_sigchld--;
+ }
+ break;
+ }
+ }
+ if (i >= NSIG)
+ break;
+ }
+ in_dotrap--;
+}
+
+
+/*
+ * Controls whether the shell is interactive or not.
+ */
+void
+setinteractive(int on)
+{
+ static int is_interactive = -1;
+
+ if (on == is_interactive)
+ return;
+ setsignal(SIGINT);
+ setsignal(SIGQUIT);
+ setsignal(SIGTERM);
+ is_interactive = on;
+}
+
+
+/*
+ * Called to exit the shell.
+ */
+void
+exitshell(int status)
+{
+ TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
+ exiting = 1;
+ exiting_exitstatus = status;
+ exitshell_savedstatus();
+}
+
+void
+exitshell_savedstatus(void)
+{
+ struct jmploc loc1, loc2;
+ char *p;
+ int sig = 0;
+ sigset_t sigs;
+
+ if (!exiting) {
+ if (in_dotrap && last_trapsig) {
+ sig = last_trapsig;
+ exiting_exitstatus = sig + 128;
+ } else
+ exiting_exitstatus = oexitstatus;
+ }
+ exitstatus = oexitstatus = exiting_exitstatus;
+ if (!setjmp(loc1.loc)) {
+ handler = &loc1;
+ if ((p = trap[0]) != NULL && *p != '\0') {
+ /*
+ * Reset evalskip, or the trap on EXIT could be
+ * interrupted if the last command was a "return".
+ */
+ evalskip = 0;
+ trap[0] = NULL;
+ evalstring(p, 0);
+ }
+ }
+ if (!setjmp(loc2.loc)) {
+ handler = &loc2; /* probably unnecessary */
+ flushall();
+#if JOBS
+ setjobctl(0);
+#endif
+ }
+ if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
+ sig != SIGTTOU) {
+ signal(sig, SIG_DFL);
+ sigemptyset(&sigs);
+ sigaddset(&sigs, sig);
+ sigprocmask(SIG_UNBLOCK, &sigs, NULL);
+ kill(getpid(), sig);
+ /* If the default action is to ignore, fall back to _exit(). */
+ }
+ _exit(exiting_exitstatus);
+}
projects / apple / shell_cmds.git / blobdiff