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36 * @(#)trap.c 8.5 (Berkeley) 6/5/95
37 * $FreeBSD: src/bin/sh/trap.c,v 1.20.2.2 2002/08/27 01:36:28 tjr Exp $
38 * $DragonFly: src/bin/sh/trap.c,v 1.4 2004/01/30 18:21:18 dillon Exp $
47 #include "nodes.h" /* for other headers */
58 #include "myhistedit.h"
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 MKINIT char sigmode[NSIG]; /* current value of signal */
75 int pendingsigs; /* indicates some signal received */
76 int in_dotrap; /* do we execute in a trap handler? */
77 static char *volatile trap[NSIG]; /* trap handler commands */
78 static volatile sig_atomic_t gotsig[NSIG];
79 /* indicates specified signal received */
80 static int ignore_sigchld; /* Used while handling SIGCHLD traps. */
81 volatile sig_atomic_t gotwinch;
83 static int getsigaction(int, sig_t *);
87 * Map a string to a signal number.
89 * Note: the signal number may exceed NSIG.
92 sigstring_to_signum(char *sig)
99 return ((signo >= 0 && signo < NSIG) ? signo : (-1));
100 } else if (strcasecmp(sig, "exit") == 0) {
105 if (strncasecmp(sig, "sig", 3) == 0)
107 for (n = 1; n < sys_nsig; n++) {
108 if (sys_signame[n] && strcasecmp(sys_signame[n], sig) == 0)
117 * Print a list of valid signal names.
125 for (n = 1; n < sys_nsig; n++) {
126 if (sys_signame[n]) {
127 out1fmt("%s", sys_signame[n]);
128 outlen += strlen(sys_signame[n]);
131 outlen += 3; /* good enough */
134 if (outlen > 70 || n == sys_nsig - 1) {
148 trapcmd(int argc, char **argv)
154 for (signo = 0 ; signo < sys_nsig; signo++) {
155 if (signo < NSIG && trap[signo] != NULL) {
157 out1fmt("trap -- '%s' %s\n",
158 trap[signo], "exit");
159 } else if (sys_signame[signo]) {
160 out1fmt("trap -- '%s' %s\n",
164 out1fmt("trap -- '%s' %d\n",
172 if (*++argv && strcmp(*argv, "--") == 0)
174 if (*argv && sigstring_to_signum(*argv) == -1) {
175 if ((*argv)[0] != '-') {
178 } else if ((*argv)[1] == '\0') {
180 } else if ((*argv)[1] == 'l' && (*argv)[2] == '\0') {
184 error("bad option %s", *argv);
188 if ((signo = sigstring_to_signum(*argv)) == -1)
189 error("bad signal %s", *argv);
192 action = savestr(action);
195 trap[signo] = action;
206 * Clear traps on a fork.
213 for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
214 if (*tp && **tp) { /* trap not NULL or SIG_IGN */
219 setsignal(tp - trap);
227 * Set the signal handler for the specified signal. The routine figures
228 * out what it should be set to.
234 sig_t sig, sigact = SIG_DFL;
237 if ((t = trap[signo]) == NULL)
243 if (action == S_DFL) {
260 if (rootshell && iflag)
266 if (rootshell && mflag)
272 if (rootshell && iflag)
282 * current setting unknown
284 if (!getsigaction(signo, &sigact)) {
286 * Pretend it worked; maybe we should give a warning
287 * here, but other shells don't. We don't alter
288 * sigmode, so that we retry every time.
292 if (sigact == SIG_IGN) {
293 if (mflag && (signo == SIGTSTP ||
294 signo == SIGTTIN || signo == SIGTTOU)) {
295 *t = S_IGN; /* don't hard ignore these */
299 *t = S_RESET; /* force to be set */
302 if (*t == S_HARD_IGN || *t == action)
305 case S_DFL: sigact = SIG_DFL; break;
306 case S_CATCH: sigact = onsig; break;
307 case S_IGN: sigact = SIG_IGN; break;
310 sig = signal(signo, sigact);
311 if (sig != SIG_ERR && action == S_CATCH)
312 siginterrupt(signo, 1);
317 * Return the current setting for sig w/o changing it.
320 getsigaction(int signo, sig_t *sigact)
324 if (sigaction(signo, (struct sigaction *)0, &sa) == -1)
326 *sigact = (sig_t) sa.sa_handler;
338 if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
339 signal(signo, SIG_IGN);
341 sigmode[signo] = S_HARD_IGN;
353 for (sm = sigmode ; sm < sigmode + NSIG ; sm++) {
368 if (signo == SIGINT && trap[SIGINT] == NULL) {
373 if (signo != SIGCHLD || !ignore_sigchld)
377 /* If we are currently in a wait builtin, prepare to break it */
378 if ((signo == SIGINT || signo == SIGQUIT) && in_waitcmd != 0)
381 * If a trap is set, not ignored and not the null command, we need
382 * to make sure traps are executed even when a child blocks signals.
385 trap[signo] != NULL &&
386 ! trap[signo][0] == '\0' &&
387 ! (trap[signo][0] == ':' && trap[signo][1] == '\0'))
391 if (signo == SIGWINCH)
398 * Called to execute a trap. Perhaps we should avoid entering new trap
399 * handlers while we are executing a trap handler.
409 for (i = 1; i < NSIG; i++) {
414 * Ignore SIGCHLD to avoid infinite recursion
415 * if the trap action does a fork.
419 savestatus = exitstatus;
421 exitstatus = savestatus;
437 * Controls whether the shell is interactive or not.
440 setinteractive(int on)
442 static int is_interactive = -1;
444 if (on == is_interactive)
457 * Called to exit the shell.
460 exitshell(int status)
462 struct jmploc loc1, loc2;
465 TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
466 if (setjmp(loc1.loc)) {
469 if (setjmp(loc2.loc)) {
473 if ((p = trap[0]) != NULL && *p != '\0') {
477 l1: handler = &loc2; /* probably unnecessary */