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 */
59 #include "myhistedit.h"
63 * Sigmode records the current value of the signal handlers for the various
64 * modes. A value of zero means that the current handler is not known.
65 * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
68 #define S_DFL 1 /* default signal handling (SIG_DFL) */
69 #define S_CATCH 2 /* signal is caught */
70 #define S_IGN 3 /* signal is ignored (SIG_IGN) */
71 #define S_HARD_IGN 4 /* signal is ignored permanently */
72 #define S_RESET 5 /* temporary - to reset a hard ignored sig */
75 static char sigmode[NSIG]; /* current value of signal */
76 volatile sig_atomic_t pendingsig; /* indicates some signal received */
77 volatile sig_atomic_t pendingsig_waitcmd; /* indicates wait builtin should be interrupted */
78 static int in_dotrap; /* do we execute in a trap handler? */
79 static char *volatile trap[NSIG]; /* trap handler commands */
80 static volatile sig_atomic_t gotsig[NSIG];
81 /* indicates specified signal received */
82 static int ignore_sigchld; /* Used while handling SIGCHLD traps. */
83 static int last_trapsig;
85 static int exiting; /* exitshell() has been called */
86 static int exiting_exitstatus; /* value passed to exitshell() */
88 static int getsigaction(int, sig_t *);
92 * Map a string to a signal number.
94 * Note: the signal number may exceed NSIG.
97 sigstring_to_signum(char *sig)
100 if (is_number(sig)) {
104 return ((signo >= 0 && signo < NSIG) ? signo : (-1));
105 } else if (strcasecmp(sig, "EXIT") == 0) {
110 if (strncasecmp(sig, "SIG", 3) == 0)
112 for (n = 1; n < sys_nsig; n++)
113 if (sys_signame[n] &&
114 strcasecmp(sys_signame[n], sig) == 0)
122 * Print a list of valid signal names.
130 for (n = 1; n < sys_nsig; n++) {
131 if (sys_signame[n]) {
132 out1fmt("%s", sys_signame[n]);
133 outlen += strlen(sys_signame[n]);
136 outlen += 3; /* good enough */
139 if (outlen > 71 || n == sys_nsig - 1) {
153 trapcmd(int argc __unused, char **argv)
160 while ((i = nextopt("l")) != '\0') {
170 for (signo = 0 ; signo < sys_nsig ; signo++) {
171 if (signo < NSIG && trap[signo] != NULL) {
173 out1qstr(trap[signo]);
176 } else if (sys_signame[signo]) {
177 out1fmt(" %s\n", sys_signame[signo]);
179 out1fmt(" %d\n", signo);
186 if (*argv && !is_number(*argv)) {
187 if (strcmp(*argv, "-") == 0)
194 for (; *argv; argv++) {
195 if ((signo = sigstring_to_signum(*argv)) == -1) {
196 warning("bad signal %s", *argv);
202 action = savestr(action);
205 trap[signo] = action;
215 * Clear traps on a fork.
222 for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
223 if (*tp && **tp) { /* trap not NULL or SIG_IGN */
228 setsignal(tp - trap);
236 * Check if we have any traps enabled.
243 for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
244 if (*tp && **tp) /* trap not NULL or SIG_IGN */
251 * Set the signal handler for the specified signal. The routine figures
252 * out what it should be set to.
258 sig_t sigact = SIG_DFL;
262 if ((t = trap[signo]) == NULL)
268 if (action == S_DFL) {
285 if (rootshell && iflag)
291 if (rootshell && mflag)
301 * current setting unknown
303 if (!getsigaction(signo, &sigact)) {
305 * Pretend it worked; maybe we should give a warning
306 * here, but other shells don't. We don't alter
307 * sigmode, so that we retry every time.
311 if (sigact == SIG_IGN) {
312 if (mflag && (signo == SIGTSTP ||
313 signo == SIGTTIN || signo == SIGTTOU)) {
314 *t = S_IGN; /* don't hard ignore these */
318 *t = S_RESET; /* force to be set */
321 if (*t == S_HARD_IGN || *t == action)
324 case S_DFL: sigact = SIG_DFL; break;
325 case S_CATCH: sigact = onsig; break;
326 case S_IGN: sigact = SIG_IGN; break;
329 sa.sa_handler = sigact;
331 sigemptyset(&sa.sa_mask);
332 sigaction(signo, &sa, NULL);
337 * Return the current setting for sig w/o changing it.
340 getsigaction(int signo, sig_t *sigact)
344 if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
346 *sigact = (sig_t) sa.sa_handler;
358 if (sigmode[signo] == 0)
360 if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
361 signal(signo, SIG_IGN);
362 sigmode[signo] = S_IGN;
368 issigchldtrapped(void)
371 return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0');
382 if (signo == SIGINT && trap[SIGINT] == NULL) {
384 * The !in_dotrap here is safe. The only way we can arrive
385 * here with in_dotrap set is that a trap handler set SIGINT to
386 * SIG_DFL and killed itself.
388 if (suppressint && !in_dotrap)
395 /* If we are currently in a wait builtin, prepare to break it */
396 if (signo == SIGINT || signo == SIGQUIT)
397 pendingsig_waitcmd = signo;
399 if (trap[signo] != NULL && trap[signo][0] != '\0' &&
400 (signo != SIGCHLD || !ignore_sigchld)) {
403 pendingsig_waitcmd = signo;
409 * Called to execute a trap. Perhaps we should avoid entering new trap
410 * handlers while we are executing a trap handler.
416 int savestatus, prev_evalskip, prev_skipcount;
421 pendingsig_waitcmd = 0;
422 for (i = 1; i < NSIG; i++) {
427 * Ignore SIGCHLD to avoid infinite
428 * recursion if the trap action does
435 * Backup current evalskip
436 * state and reset it before
437 * executing a trap, so that the
438 * trap is not disturbed by an
439 * ongoing break/continue/return
442 prev_evalskip = evalskip;
443 prev_skipcount = skipcount;
447 savestatus = exitstatus;
448 evalstring(trap[i], 0);
451 * If such a command was not
452 * already in progress, allow a
453 * break/continue/return in the
454 * trap action to have an effect
458 prev_evalskip != 0) {
459 evalskip = prev_evalskip;
460 skipcount = prev_skipcount;
461 exitstatus = savestatus;
478 * Controls whether the shell is interactive or not.
481 setinteractive(int on)
483 static int is_interactive = -1;
485 if (on == is_interactive)
495 * Called to exit the shell.
498 exitshell(int status)
500 TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
502 exiting_exitstatus = status;
503 exitshell_savedstatus();
507 exitshell_savedstatus(void)
509 struct jmploc loc1, loc2;
515 if (in_dotrap && last_trapsig) {
517 exiting_exitstatus = sig + 128;
519 exiting_exitstatus = oexitstatus;
521 exitstatus = oexitstatus = exiting_exitstatus;
522 if (!setjmp(loc1.loc)) {
524 if ((p = trap[0]) != NULL && *p != '\0') {
526 * Reset evalskip, or the trap on EXIT could be
527 * interrupted if the last command was a "return".
534 if (!setjmp(loc2.loc)) {
535 handler = &loc2; /* probably unnecessary */
541 if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
543 signal(sig, SIG_DFL);
545 sigaddset(&sigs, sig);
546 sigprocmask(SIG_UNBLOCK, &sigs, NULL);
548 /* If the default action is to ignore, fall back to _exit(). */
550 _exit(exiting_exitstatus);