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 SIGINT/SIGQUIT received */
78 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 volatile sig_atomic_t gotwinch;
84 static int last_trapsig;
86 static int exiting; /* exitshell() has been called */
87 static int exiting_exitstatus; /* value passed to exitshell() */
89 static int getsigaction(int, sig_t *);
93 * Map a string to a signal number.
95 * Note: the signal number may exceed NSIG.
98 sigstring_to_signum(char *sig)
101 if (is_number(sig)) {
105 return ((signo >= 0 && signo < NSIG) ? signo : (-1));
106 } else if (strcasecmp(sig, "EXIT") == 0) {
111 if (strncasecmp(sig, "SIG", 3) == 0)
113 for (n = 1; n < sys_nsig; n++)
114 if (sys_signame[n] &&
115 strcasecmp(sys_signame[n], sig) == 0)
123 * Print a list of valid signal names.
131 for (n = 1; n < sys_nsig; n++) {
132 if (sys_signame[n]) {
133 out1fmt("%s", sys_signame[n]);
134 outlen += strlen(sys_signame[n]);
137 outlen += 3; /* good enough */
140 if (outlen > 71 || n == sys_nsig - 1) {
154 trapcmd(int argc __unused, char **argv)
161 while ((i = nextopt("l")) != '\0') {
171 for (signo = 0 ; signo < sys_nsig ; signo++) {
172 if (signo < NSIG && trap[signo] != NULL) {
174 out1qstr(trap[signo]);
177 } else if (sys_signame[signo]) {
178 out1fmt(" %s\n", sys_signame[signo]);
180 out1fmt(" %d\n", signo);
187 if (*argv && sigstring_to_signum(*argv) == -1) {
188 if (strcmp(*argv, "-") == 0)
195 for (; *argv; argv++) {
196 if ((signo = sigstring_to_signum(*argv)) == -1) {
197 warning("bad signal %s", *argv);
203 action = savestr(action);
206 trap[signo] = action;
216 * Clear traps on a fork.
223 for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
224 if (*tp && **tp) { /* trap not NULL or SIG_IGN */
229 setsignal(tp - trap);
237 * Check if we have any traps enabled.
244 for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
245 if (*tp && **tp) /* trap not NULL or SIG_IGN */
252 * Set the signal handler for the specified signal. The routine figures
253 * out what it should be set to.
259 sig_t sigact = SIG_DFL;
263 if ((t = trap[signo]) == NULL)
269 if (action == S_DFL) {
286 if (rootshell && iflag)
292 if (rootshell && mflag)
298 if (rootshell && iflag)
308 * current setting unknown
310 if (!getsigaction(signo, &sigact)) {
312 * Pretend it worked; maybe we should give a warning
313 * here, but other shells don't. We don't alter
314 * sigmode, so that we retry every time.
318 if (sigact == SIG_IGN) {
319 if (mflag && (signo == SIGTSTP ||
320 signo == SIGTTIN || signo == SIGTTOU)) {
321 *t = S_IGN; /* don't hard ignore these */
325 *t = S_RESET; /* force to be set */
328 if (*t == S_HARD_IGN || *t == action)
331 case S_DFL: sigact = SIG_DFL; break;
332 case S_CATCH: sigact = onsig; break;
333 case S_IGN: sigact = SIG_IGN; break;
336 sa.sa_handler = sigact;
338 sigemptyset(&sa.sa_mask);
339 sigaction(signo, &sa, NULL);
344 * Return the current setting for sig w/o changing it.
347 getsigaction(int signo, sig_t *sigact)
351 if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
353 *sigact = (sig_t) sa.sa_handler;
365 if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
366 signal(signo, SIG_IGN);
368 sigmode[signo] = S_HARD_IGN;
373 issigchldtrapped(void)
376 return (trap[SIGCHLD] != NULL && *trap[SIGCHLD] != '\0');
387 if (signo == SIGINT && trap[SIGINT] == NULL) {
392 /* If we are currently in a wait builtin, prepare to break it */
393 if (signo == SIGINT || signo == SIGQUIT)
394 pendingsig_waitcmd = signo;
396 if (trap[signo] != NULL && trap[signo][0] != '\0' &&
397 (signo != SIGCHLD || !ignore_sigchld)) {
403 if (signo == SIGWINCH)
410 * Called to execute a trap. Perhaps we should avoid entering new trap
411 * handlers while we are executing a trap handler.
417 int savestatus, prev_evalskip, prev_skipcount;
422 pendingsig_waitcmd = 0;
423 for (i = 1; i < NSIG; i++) {
428 * Ignore SIGCHLD to avoid infinite
429 * recursion if the trap action does
436 * Backup current evalskip
437 * state and reset it before
438 * executing a trap, so that the
439 * trap is not disturbed by an
440 * ongoing break/continue/return
443 prev_evalskip = evalskip;
444 prev_skipcount = skipcount;
448 savestatus = exitstatus;
449 evalstring(trap[i], 0);
452 * If such a command was not
453 * already in progress, allow a
454 * break/continue/return in the
455 * trap action to have an effect
459 prev_evalskip != 0) {
460 evalskip = prev_evalskip;
461 skipcount = prev_skipcount;
462 exitstatus = savestatus;
479 * Controls whether the shell is interactive or not.
482 setinteractive(int on)
484 static int is_interactive = -1;
486 if (on == is_interactive)
499 * Called to exit the shell.
502 exitshell(int status)
504 TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
506 exiting_exitstatus = status;
507 exitshell_savedstatus();
511 exitshell_savedstatus(void)
513 struct jmploc loc1, loc2;
519 if (in_dotrap && last_trapsig) {
521 exiting_exitstatus = sig + 128;
523 exiting_exitstatus = oexitstatus;
525 exitstatus = oexitstatus = exiting_exitstatus;
526 if (setjmp(loc1.loc)) {
529 if (setjmp(loc2.loc)) {
533 if ((p = trap[0]) != NULL && *p != '\0') {
535 * Reset evalskip, or the trap on EXIT could be
536 * interrupted if the last command was a "return".
542 l1: handler = &loc2; /* probably unnecessary */
548 if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
550 signal(sig, SIG_DFL);
552 sigaddset(&sigs, sig);
553 sigprocmask(SIG_UNBLOCK, &sigs, NULL);
555 /* If the default action is to ignore, fall back to _exit(). */
557 _exit(exiting_exitstatus);