efd1946c35
If job control is not enabled, background jobs started with ... & ignore SIGINT and SIGQUIT so that they are not affected by such signals that are intended for the foreground job. However, this should not prevent reassigning a different action for these signals (as if the shell invocation inherited these signal actions from its parent). Austin group issue #751 Example: { trap - INT; exec sleep 10; } & wait A Ctrl+C should terminate the sleep command.
561 lines
11 KiB
C
561 lines
11 KiB
C
/*-
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* Copyright (c) 1991, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Kenneth Almquist.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifndef lint
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#if 0
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static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95";
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#endif
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#endif /* not lint */
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <signal.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include "shell.h"
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#include "main.h"
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#include "nodes.h" /* for other headers */
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#include "eval.h"
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#include "jobs.h"
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#include "show.h"
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#include "options.h"
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#include "syntax.h"
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#include "output.h"
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#include "memalloc.h"
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#include "error.h"
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#include "trap.h"
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#include "mystring.h"
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#include "builtins.h"
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#include "myhistedit.h"
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/*
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* Sigmode records the current value of the signal handlers for the various
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* modes. A value of zero means that the current handler is not known.
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* S_HARD_IGN indicates that the signal was ignored on entry to the shell,
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*/
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#define S_DFL 1 /* default signal handling (SIG_DFL) */
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#define S_CATCH 2 /* signal is caught */
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#define S_IGN 3 /* signal is ignored (SIG_IGN) */
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#define S_HARD_IGN 4 /* signal is ignored permanently */
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#define S_RESET 5 /* temporary - to reset a hard ignored sig */
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static char sigmode[NSIG]; /* current value of signal */
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volatile sig_atomic_t pendingsig; /* indicates some signal received */
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volatile sig_atomic_t pendingsig_waitcmd; /* indicates SIGINT/SIGQUIT received */
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int in_dotrap; /* do we execute in a trap handler? */
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static char *volatile trap[NSIG]; /* trap handler commands */
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static volatile sig_atomic_t gotsig[NSIG];
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/* indicates specified signal received */
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static int ignore_sigchld; /* Used while handling SIGCHLD traps. */
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volatile sig_atomic_t gotwinch;
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static int last_trapsig;
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static int exiting; /* exitshell() has been called */
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static int exiting_exitstatus; /* value passed to exitshell() */
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static int getsigaction(int, sig_t *);
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/*
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* Map a string to a signal number.
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*
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* Note: the signal number may exceed NSIG.
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*/
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static int
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sigstring_to_signum(char *sig)
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{
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if (is_number(sig)) {
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int signo;
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signo = atoi(sig);
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return ((signo >= 0 && signo < NSIG) ? signo : (-1));
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} else if (strcasecmp(sig, "EXIT") == 0) {
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return (0);
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} else {
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int n;
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if (strncasecmp(sig, "SIG", 3) == 0)
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sig += 3;
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for (n = 1; n < sys_nsig; n++)
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if (sys_signame[n] &&
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strcasecmp(sys_signame[n], sig) == 0)
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return (n);
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}
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return (-1);
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}
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/*
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* Print a list of valid signal names.
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*/
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static void
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printsignals(void)
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{
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int n, outlen;
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outlen = 0;
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for (n = 1; n < sys_nsig; n++) {
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if (sys_signame[n]) {
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out1fmt("%s", sys_signame[n]);
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outlen += strlen(sys_signame[n]);
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} else {
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out1fmt("%d", n);
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outlen += 3; /* good enough */
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}
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++outlen;
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if (outlen > 71 || n == sys_nsig - 1) {
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out1str("\n");
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outlen = 0;
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} else {
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out1c(' ');
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}
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}
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}
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/*
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* The trap builtin.
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*/
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int
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trapcmd(int argc __unused, char **argv)
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{
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char *action;
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int signo;
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int errors = 0;
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int i;
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while ((i = nextopt("l")) != '\0') {
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switch (i) {
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case 'l':
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printsignals();
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return (0);
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}
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}
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argv = argptr;
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if (*argv == NULL) {
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for (signo = 0 ; signo < sys_nsig ; signo++) {
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if (signo < NSIG && trap[signo] != NULL) {
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out1str("trap -- ");
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out1qstr(trap[signo]);
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if (signo == 0) {
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out1str(" EXIT\n");
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} else if (sys_signame[signo]) {
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out1fmt(" %s\n", sys_signame[signo]);
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} else {
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out1fmt(" %d\n", signo);
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}
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}
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}
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return 0;
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}
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action = NULL;
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if (*argv && sigstring_to_signum(*argv) == -1) {
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if (strcmp(*argv, "-") == 0)
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argv++;
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else {
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action = *argv;
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argv++;
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}
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}
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for (; *argv; argv++) {
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if ((signo = sigstring_to_signum(*argv)) == -1) {
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warning("bad signal %s", *argv);
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errors = 1;
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continue;
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}
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INTOFF;
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if (action)
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action = savestr(action);
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if (trap[signo])
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ckfree(trap[signo]);
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trap[signo] = action;
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if (signo != 0)
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setsignal(signo);
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INTON;
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}
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return errors;
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}
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/*
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* Clear traps on a fork.
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*/
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void
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clear_traps(void)
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{
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char *volatile *tp;
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for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
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if (*tp && **tp) { /* trap not NULL or SIG_IGN */
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INTOFF;
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ckfree(*tp);
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*tp = NULL;
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if (tp != &trap[0])
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setsignal(tp - trap);
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INTON;
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}
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}
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}
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/*
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* Check if we have any traps enabled.
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*/
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int
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have_traps(void)
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{
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char *volatile *tp;
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for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
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if (*tp && **tp) /* trap not NULL or SIG_IGN */
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return 1;
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}
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return 0;
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}
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/*
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* Set the signal handler for the specified signal. The routine figures
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* out what it should be set to.
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*/
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void
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setsignal(int signo)
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{
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int action;
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sig_t sigact = SIG_DFL;
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struct sigaction sa;
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char *t;
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if ((t = trap[signo]) == NULL)
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action = S_DFL;
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else if (*t != '\0')
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action = S_CATCH;
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else
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action = S_IGN;
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if (action == S_DFL) {
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switch (signo) {
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case SIGINT:
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action = S_CATCH;
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break;
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case SIGQUIT:
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#ifdef DEBUG
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{
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extern int debug;
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if (debug)
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break;
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}
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#endif
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action = S_CATCH;
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break;
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case SIGTERM:
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if (rootshell && iflag)
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action = S_IGN;
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break;
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#if JOBS
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case SIGTSTP:
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case SIGTTOU:
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if (rootshell && mflag)
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action = S_IGN;
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break;
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#endif
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#ifndef NO_HISTORY
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case SIGWINCH:
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if (rootshell && iflag)
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action = S_CATCH;
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break;
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#endif
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}
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}
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t = &sigmode[signo];
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if (*t == 0) {
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/*
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* current setting unknown
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*/
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if (!getsigaction(signo, &sigact)) {
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/*
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* Pretend it worked; maybe we should give a warning
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* here, but other shells don't. We don't alter
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* sigmode, so that we retry every time.
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*/
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return;
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}
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if (sigact == SIG_IGN) {
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if (mflag && (signo == SIGTSTP ||
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signo == SIGTTIN || signo == SIGTTOU)) {
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*t = S_IGN; /* don't hard ignore these */
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} else
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*t = S_HARD_IGN;
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} else {
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*t = S_RESET; /* force to be set */
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}
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}
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if (*t == S_HARD_IGN || *t == action)
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return;
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switch (action) {
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case S_DFL: sigact = SIG_DFL; break;
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case S_CATCH: sigact = onsig; break;
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case S_IGN: sigact = SIG_IGN; break;
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}
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*t = action;
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sa.sa_handler = sigact;
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sa.sa_flags = 0;
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sigemptyset(&sa.sa_mask);
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sigaction(signo, &sa, NULL);
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}
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/*
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* Return the current setting for sig w/o changing it.
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*/
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static int
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getsigaction(int signo, sig_t *sigact)
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{
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struct sigaction sa;
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if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
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return 0;
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*sigact = (sig_t) sa.sa_handler;
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return 1;
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}
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/*
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* Ignore a signal.
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*/
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void
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ignoresig(int signo)
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{
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if (sigmode[signo] == 0)
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setsignal(signo);
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if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
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signal(signo, SIG_IGN);
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sigmode[signo] = S_IGN;
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}
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}
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int
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issigchldtrapped(void)
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{
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return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0');
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}
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/*
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* Signal handler.
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*/
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void
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onsig(int signo)
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{
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if (signo == SIGINT && trap[SIGINT] == NULL) {
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onint();
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return;
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}
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/* If we are currently in a wait builtin, prepare to break it */
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if (signo == SIGINT || signo == SIGQUIT)
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pendingsig_waitcmd = signo;
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if (trap[signo] != NULL && trap[signo][0] != '\0' &&
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(signo != SIGCHLD || !ignore_sigchld)) {
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gotsig[signo] = 1;
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pendingsig = signo;
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}
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#ifndef NO_HISTORY
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if (signo == SIGWINCH)
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gotwinch = 1;
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#endif
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}
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/*
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* Called to execute a trap. Perhaps we should avoid entering new trap
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* handlers while we are executing a trap handler.
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*/
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void
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dotrap(void)
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{
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int i;
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int savestatus, prev_evalskip, prev_skipcount;
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in_dotrap++;
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for (;;) {
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pendingsig = 0;
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pendingsig_waitcmd = 0;
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for (i = 1; i < NSIG; i++) {
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if (gotsig[i]) {
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gotsig[i] = 0;
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if (trap[i]) {
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/*
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* Ignore SIGCHLD to avoid infinite
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* recursion if the trap action does
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* a fork.
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*/
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if (i == SIGCHLD)
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ignore_sigchld++;
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/*
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* Backup current evalskip
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* state and reset it before
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* executing a trap, so that the
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* trap is not disturbed by an
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* ongoing break/continue/return
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* statement.
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*/
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prev_evalskip = evalskip;
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prev_skipcount = skipcount;
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evalskip = 0;
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last_trapsig = i;
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savestatus = exitstatus;
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evalstring(trap[i], 0);
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/*
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* If such a command was not
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* already in progress, allow a
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* break/continue/return in the
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* trap action to have an effect
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* outside of it.
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*/
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if (evalskip == 0 ||
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prev_evalskip != 0) {
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evalskip = prev_evalskip;
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skipcount = prev_skipcount;
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exitstatus = savestatus;
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}
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if (i == SIGCHLD)
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ignore_sigchld--;
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}
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break;
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}
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}
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if (i >= NSIG)
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break;
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}
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in_dotrap--;
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}
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/*
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* Controls whether the shell is interactive or not.
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*/
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void
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setinteractive(int on)
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{
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static int is_interactive = -1;
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if (on == is_interactive)
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return;
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setsignal(SIGINT);
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setsignal(SIGQUIT);
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setsignal(SIGTERM);
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#ifndef NO_HISTORY
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setsignal(SIGWINCH);
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#endif
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is_interactive = on;
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}
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/*
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* Called to exit the shell.
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*/
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void
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exitshell(int status)
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{
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TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
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exiting = 1;
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exiting_exitstatus = status;
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exitshell_savedstatus();
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}
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void
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exitshell_savedstatus(void)
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{
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struct jmploc loc1, loc2;
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char *p;
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int sig = 0;
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sigset_t sigs;
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if (!exiting) {
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if (in_dotrap && last_trapsig) {
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sig = last_trapsig;
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exiting_exitstatus = sig + 128;
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} else
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exiting_exitstatus = oexitstatus;
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}
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exitstatus = oexitstatus = exiting_exitstatus;
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if (setjmp(loc1.loc)) {
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goto l1;
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}
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if (setjmp(loc2.loc)) {
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goto l2;
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}
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handler = &loc1;
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if ((p = trap[0]) != NULL && *p != '\0') {
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/*
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* Reset evalskip, or the trap on EXIT could be
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* interrupted if the last command was a "return".
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*/
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evalskip = 0;
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trap[0] = NULL;
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evalstring(p, 0);
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}
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l1: handler = &loc2; /* probably unnecessary */
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flushall();
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#if JOBS
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setjobctl(0);
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#endif
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l2:
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if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
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sig != SIGTTOU) {
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signal(sig, SIG_DFL);
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sigemptyset(&sigs);
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sigaddset(&sigs, sig);
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sigprocmask(SIG_UNBLOCK, &sigs, NULL);
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kill(getpid(), sig);
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/* If the default action is to ignore, fall back to _exit(). */
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}
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_exit(exiting_exitstatus);
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}
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