2 * Copyright (c) 1991, 1993
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35 static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95";
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
47 #include "nodes.h" /* for other headers */
62 * Sigmode records the current value of the signal handlers for the various
63 * modes. A value of zero means that the current handler is not known.
64 * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
67 #define S_DFL 1 /* default signal handling (SIG_DFL) */
68 #define S_CATCH 2 /* signal is caught */
69 #define S_IGN 3 /* signal is ignored (SIG_IGN) */
70 #define S_HARD_IGN 4 /* signal is ignored permanently */
71 #define S_RESET 5 /* temporary - to reset a hard ignored sig */
74 static char sigmode[NSIG]; /* current value of signal */
75 volatile sig_atomic_t pendingsig; /* indicates some signal received */
76 volatile sig_atomic_t pendingsig_waitcmd; /* indicates wait builtin should be interrupted */
77 static int in_dotrap; /* do we execute in a trap handler? */
78 static char *volatile trap[NSIG]; /* trap handler commands */
79 static volatile sig_atomic_t gotsig[NSIG];
80 /* indicates specified signal received */
81 static int ignore_sigchld; /* Used while handling SIGCHLD traps. */
82 static int last_trapsig;
84 static int exiting; /* exitshell() has been called */
85 static int exiting_exitstatus; /* value passed to exitshell() */
87 static int getsigaction(int, sig_t *);
91 * Map a string to a signal number.
93 * Note: the signal number may exceed NSIG.
96 sigstring_to_signum(char *sig)
103 return ((signo >= 0 && signo < NSIG) ? signo : (-1));
104 } else if (strcasecmp(sig, "EXIT") == 0) {
109 if (strncasecmp(sig, "SIG", 3) == 0)
111 for (n = 1; n < sys_nsig; n++)
112 if (sys_signame[n] &&
113 strcasecmp(sys_signame[n], sig) == 0)
121 * Print a list of valid signal names.
129 for (n = 1; n < sys_nsig; n++) {
130 if (sys_signame[n]) {
131 out1fmt("%s", sys_signame[n]);
132 outlen += strlen(sys_signame[n]);
135 outlen += 3; /* good enough */
138 if (outlen > 71 || n == sys_nsig - 1) {
152 trapcmd(int argc __unused, char **argv)
159 while ((i = nextopt("l")) != '\0') {
169 for (signo = 0 ; signo < sys_nsig ; signo++) {
170 if (signo < NSIG && trap[signo] != NULL) {
172 out1qstr(trap[signo]);
175 } else if (sys_signame[signo]) {
176 out1fmt(" %s\n", sys_signame[signo]);
178 out1fmt(" %d\n", signo);
185 if (*argv && !is_number(*argv)) {
186 if (strcmp(*argv, "-") == 0)
193 for (; *argv; argv++) {
194 if ((signo = sigstring_to_signum(*argv)) == -1) {
195 warning("bad signal %s", *argv);
201 action = savestr(action);
204 trap[signo] = action;
214 * Clear traps on a fork.
221 for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
222 if (*tp && **tp) { /* trap not NULL or SIG_IGN */
227 setsignal(tp - trap);
235 * Check if we have any traps enabled.
242 for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
243 if (*tp && **tp) /* trap not NULL or SIG_IGN */
250 * Set the signal handler for the specified signal. The routine figures
251 * out what it should be set to.
257 sig_t sigact = SIG_DFL;
261 if ((t = trap[signo]) == NULL)
267 if (action == S_DFL) {
284 if (rootshell && iflag)
290 if (rootshell && mflag)
300 * current setting unknown
302 if (!getsigaction(signo, &sigact)) {
304 * Pretend it worked; maybe we should give a warning
305 * here, but other shells don't. We don't alter
306 * sigmode, so that we retry every time.
310 if (sigact == SIG_IGN) {
311 if (mflag && (signo == SIGTSTP ||
312 signo == SIGTTIN || signo == SIGTTOU)) {
313 *t = S_IGN; /* don't hard ignore these */
317 *t = S_RESET; /* force to be set */
320 if (*t == S_HARD_IGN || *t == action)
323 case S_DFL: sigact = SIG_DFL; break;
324 case S_CATCH: sigact = onsig; break;
325 case S_IGN: sigact = SIG_IGN; break;
328 sa.sa_handler = sigact;
330 sigemptyset(&sa.sa_mask);
331 sigaction(signo, &sa, NULL);
336 * Return the current setting for sig w/o changing it.
339 getsigaction(int signo, sig_t *sigact)
343 if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
345 *sigact = (sig_t) sa.sa_handler;
357 if (sigmode[signo] == 0)
359 if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
360 signal(signo, SIG_IGN);
361 sigmode[signo] = S_IGN;
367 issigchldtrapped(void)
370 return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0');
381 if (signo == SIGINT && trap[SIGINT] == NULL) {
383 * The !in_dotrap here is safe. The only way we can arrive
384 * here with in_dotrap set is that a trap handler set SIGINT to
385 * SIG_DFL and killed itself.
387 if (suppressint && !in_dotrap)
394 /* If we are currently in a wait builtin, prepare to break it */
395 if (signo == SIGINT || signo == SIGQUIT)
396 pendingsig_waitcmd = signo;
398 if (trap[signo] != NULL && trap[signo][0] != '\0' &&
399 (signo != SIGCHLD || !ignore_sigchld)) {
402 pendingsig_waitcmd = signo;
408 * Called to execute a trap. Perhaps we should avoid entering new trap
409 * handlers while we are executing a trap handler.
415 int savestatus, prev_evalskip, prev_skipcount;
420 pendingsig_waitcmd = 0;
421 for (i = 1; i < NSIG; i++) {
426 * Ignore SIGCHLD to avoid infinite
427 * recursion if the trap action does
434 * Backup current evalskip
435 * state and reset it before
436 * executing a trap, so that the
437 * trap is not disturbed by an
438 * ongoing break/continue/return
441 prev_evalskip = evalskip;
442 prev_skipcount = skipcount;
446 savestatus = exitstatus;
447 evalstring(trap[i], 0);
450 * If such a command was not
451 * already in progress, allow a
452 * break/continue/return in the
453 * trap action to have an effect
457 prev_evalskip != 0) {
458 evalskip = prev_evalskip;
459 skipcount = prev_skipcount;
460 exitstatus = savestatus;
477 * Controls whether the shell is interactive or not.
480 setinteractive(int on)
482 static int is_interactive = -1;
484 if (on == is_interactive)
494 * Called to exit the shell.
497 exitshell(int status)
499 TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
501 exiting_exitstatus = status;
502 exitshell_savedstatus();
506 exitshell_savedstatus(void)
508 struct jmploc loc1, loc2;
514 if (in_dotrap && last_trapsig) {
516 exiting_exitstatus = sig + 128;
518 exiting_exitstatus = oexitstatus;
520 exitstatus = oexitstatus = exiting_exitstatus;
521 if (!setjmp(loc1.loc)) {
523 if ((p = trap[0]) != NULL && *p != '\0') {
525 * Reset evalskip, or the trap on EXIT could be
526 * interrupted if the last command was a "return".
533 if (!setjmp(loc2.loc)) {
534 handler = &loc2; /* probably unnecessary */
540 if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
542 signal(sig, SIG_DFL);
544 sigaddset(&sigs, sig);
545 sigprocmask(SIG_UNBLOCK, &sigs, NULL);
547 /* If the default action is to ignore, fall back to _exit(). */
549 _exit(exiting_exitstatus);