sh: Fix duplicate prototypes for builtins.
[dragonfly.git] / bin / sh / trap.c
CommitLineData
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1/*-
2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Kenneth Almquist.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 * must display the following acknowledgement:
18 * This product includes software developed by the University of
19 * California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
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35 *
36 * @(#)trap.c 8.5 (Berkeley) 6/5/95
c3e3bc7a 37 * $FreeBSD: src/bin/sh/trap.c,v 1.46 2011/06/13 21:03:27 jilles Exp $
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38 */
39
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40#include <signal.h>
41#include <unistd.h>
42#include <stdlib.h>
43
44#include "shell.h"
45#include "main.h"
46#include "nodes.h" /* for other headers */
47#include "eval.h"
48#include "jobs.h"
49#include "show.h"
50#include "options.h"
51#include "syntax.h"
52#include "output.h"
53#include "memalloc.h"
54#include "error.h"
55#include "trap.h"
56#include "mystring.h"
c3e3bc7a 57#include "builtins.h"
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58#include "myhistedit.h"
59
60
61/*
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,
65 */
66
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 */
72
73
74MKINIT char sigmode[NSIG]; /* current value of signal */
75int pendingsigs; /* indicates some signal received */
76int in_dotrap; /* do we execute in a trap handler? */
77static char *volatile trap[NSIG]; /* trap handler commands */
89a03866 78static volatile sig_atomic_t gotsig[NSIG];
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79 /* indicates specified signal received */
80static int ignore_sigchld; /* Used while handling SIGCHLD traps. */
81volatile sig_atomic_t gotwinch;
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82static int last_trapsig;
83
84static int exiting; /* exitshell() has been called */
85static int exiting_exitstatus; /* value passed to exitshell() */
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86
87static int getsigaction(int, sig_t *);
88
89
90/*
91 * Map a string to a signal number.
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92 *
93 * Note: the signal number may exceed NSIG.
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94 */
95static int
96sigstring_to_signum(char *sig)
97{
98
99 if (is_number(sig)) {
100 int signo;
101
102 signo = atoi(sig);
103 return ((signo >= 0 && signo < NSIG) ? signo : (-1));
99512ac4 104 } else if (strcasecmp(sig, "EXIT") == 0) {
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105 return (0);
106 } else {
107 int n;
108
99512ac4 109 if (strncasecmp(sig, "SIG", 3) == 0)
984263bc 110 sig += 3;
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111 for (n = 1; n < sys_nsig; n++)
112 if (sys_signame[n] &&
113 strcasecmp(sys_signame[n], sig) == 0)
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114 return (n);
115 }
116 return (-1);
117}
118
119
120/*
121 * Print a list of valid signal names.
122 */
123static void
124printsignals(void)
125{
89a03866 126 int n, outlen;
984263bc 127
89a03866 128 outlen = 0;
14726127 129 for (n = 1; n < sys_nsig; n++) {
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130 if (sys_signame[n]) {
131 out1fmt("%s", sys_signame[n]);
132 outlen += strlen(sys_signame[n]);
133 } else {
134 out1fmt("%d", n);
135 outlen += 3; /* good enough */
136 }
137 ++outlen;
99512ac4 138 if (outlen > 71 || n == sys_nsig - 1) {
984263bc 139 out1str("\n");
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140 outlen = 0;
141 } else {
984263bc 142 out1c(' ');
02f4d240 143 }
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144 }
145}
146
147
148/*
149 * The trap builtin.
150 */
151int
99512ac4 152trapcmd(int argc __unused, char **argv)
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153{
154 char *action;
155 int signo;
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156 int errors = 0;
157 int i;
158
159 while ((i = nextopt("l")) != '\0') {
160 switch (i) {
161 case 'l':
162 printsignals();
163 return (0);
164 }
165 }
166 argv = argptr;
984263bc 167
99512ac4 168 if (*argv == NULL) {
89a03866 169 for (signo = 0 ; signo < sys_nsig ; signo++) {
02f4d240 170 if (signo < NSIG && trap[signo] != NULL) {
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171 out1str("trap -- ");
172 out1qstr(trap[signo]);
02f4d240 173 if (signo == 0) {
99512ac4 174 out1str(" EXIT\n");
02f4d240 175 } else if (sys_signame[signo]) {
89a03866 176 out1fmt(" %s\n", sys_signame[signo]);
02f4d240 177 } else {
89a03866 178 out1fmt(" %d\n", signo);
02f4d240 179 }
14726127 180 }
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181 }
182 return 0;
183 }
184 action = NULL;
984263bc 185 if (*argv && sigstring_to_signum(*argv) == -1) {
99512ac4 186 if (strcmp(*argv, "-") == 0)
984263bc 187 argv++;
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188 else {
189 action = *argv;
984263bc 190 argv++;
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191 }
192 }
193 while (*argv) {
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194 if ((signo = sigstring_to_signum(*argv)) == -1) {
195 warning("bad signal %s", *argv);
196 errors = 1;
197 }
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198 INTOFF;
199 if (action)
200 action = savestr(action);
201 if (trap[signo])
202 ckfree(trap[signo]);
203 trap[signo] = action;
204 if (signo != 0)
205 setsignal(signo);
206 INTON;
207 argv++;
208 }
99512ac4 209 return errors;
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210}
211
212
213/*
214 * Clear traps on a fork.
215 */
216void
217clear_traps(void)
218{
219 char *volatile *tp;
220
221 for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
222 if (*tp && **tp) { /* trap not NULL or SIG_IGN */
223 INTOFF;
224 ckfree(*tp);
225 *tp = NULL;
226 if (tp != &trap[0])
227 setsignal(tp - trap);
228 INTON;
229 }
230 }
231}
232
233
234/*
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235 * Check if we have any traps enabled.
236 */
237int
238have_traps(void)
239{
240 char *volatile *tp;
241
242 for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) {
243 if (*tp && **tp) /* trap not NULL or SIG_IGN */
244 return 1;
245 }
246 return 0;
247}
248
249/*
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250 * Set the signal handler for the specified signal. The routine figures
251 * out what it should be set to.
252 */
253void
254setsignal(int signo)
255{
256 int action;
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257 sig_t sigact = SIG_DFL;
258 struct sigaction sa;
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259 char *t;
260
261 if ((t = trap[signo]) == NULL)
262 action = S_DFL;
263 else if (*t != '\0')
264 action = S_CATCH;
265 else
266 action = S_IGN;
267 if (action == S_DFL) {
268 switch (signo) {
269 case SIGINT:
270 action = S_CATCH;
271 break;
272 case SIGQUIT:
273#ifdef DEBUG
274 {
275 extern int debug;
276
277 if (debug)
278 break;
279 }
280#endif
281 action = S_CATCH;
282 break;
283 case SIGTERM:
284 if (rootshell && iflag)
285 action = S_IGN;
286 break;
287#if JOBS
288 case SIGTSTP:
289 case SIGTTOU:
290 if (rootshell && mflag)
291 action = S_IGN;
292 break;
293#endif
294#ifndef NO_HISTORY
295 case SIGWINCH:
296 if (rootshell && iflag)
297 action = S_CATCH;
298 break;
299#endif
300 }
301 }
302
303 t = &sigmode[signo];
304 if (*t == 0) {
305 /*
306 * current setting unknown
307 */
308 if (!getsigaction(signo, &sigact)) {
309 /*
310 * Pretend it worked; maybe we should give a warning
311 * here, but other shells don't. We don't alter
312 * sigmode, so that we retry every time.
313 */
314 return;
315 }
316 if (sigact == SIG_IGN) {
317 if (mflag && (signo == SIGTSTP ||
318 signo == SIGTTIN || signo == SIGTTOU)) {
319 *t = S_IGN; /* don't hard ignore these */
320 } else
321 *t = S_HARD_IGN;
322 } else {
323 *t = S_RESET; /* force to be set */
324 }
325 }
326 if (*t == S_HARD_IGN || *t == action)
327 return;
328 switch (action) {
329 case S_DFL: sigact = SIG_DFL; break;
330 case S_CATCH: sigact = onsig; break;
331 case S_IGN: sigact = SIG_IGN; break;
332 }
333 *t = action;
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334 sa.sa_handler = sigact;
335 sa.sa_flags = 0;
336 sigemptyset(&sa.sa_mask);
337 sigaction(signo, &sa, NULL);
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338}
339
340
341/*
342 * Return the current setting for sig w/o changing it.
343 */
344static int
345getsigaction(int signo, sig_t *sigact)
346{
347 struct sigaction sa;
348
60233e58 349 if (sigaction(signo, NULL, &sa) == -1)
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350 return 0;
351 *sigact = (sig_t) sa.sa_handler;
352 return 1;
353}
354
355
356/*
357 * Ignore a signal.
358 */
359void
360ignoresig(int signo)
361{
362
363 if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) {
364 signal(signo, SIG_IGN);
365 }
366 sigmode[signo] = S_HARD_IGN;
367}
368
369
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370/*
371 * Signal handler.
372 */
373void
374onsig(int signo)
375{
376
377 if (signo == SIGINT && trap[SIGINT] == NULL) {
378 onint();
379 return;
380 }
381
382 if (signo != SIGCHLD || !ignore_sigchld)
383 gotsig[signo] = 1;
384 pendingsigs++;
385
386 /* If we are currently in a wait builtin, prepare to break it */
387 if ((signo == SIGINT || signo == SIGQUIT) && in_waitcmd != 0)
388 breakwaitcmd = 1;
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389 /*
390 * If a trap is set, not ignored and not the null command, we need
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391 * to make sure traps are executed even when a child blocks signals.
392 */
393 if (Tflag &&
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394 trap[signo] != NULL &&
395 ! (trap[signo][0] == '\0') &&
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396 ! (trap[signo][0] == ':' && trap[signo][1] == '\0'))
397 breakwaitcmd = 1;
398
399#ifndef NO_HISTORY
400 if (signo == SIGWINCH)
401 gotwinch = 1;
402#endif
403}
404
405
406/*
407 * Called to execute a trap. Perhaps we should avoid entering new trap
408 * handlers while we are executing a trap handler.
409 */
410void
411dotrap(void)
412{
413 int i;
414 int savestatus;
415
416 in_dotrap++;
417 for (;;) {
418 for (i = 1; i < NSIG; i++) {
419 if (gotsig[i]) {
420 gotsig[i] = 0;
421 if (trap[i]) {
422 /*
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423 * Ignore SIGCHLD to avoid infinite
424 * recursion if the trap action does
425 * a fork.
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426 */
427 if (i == SIGCHLD)
428 ignore_sigchld++;
99512ac4 429 last_trapsig = i;
984263bc 430 savestatus = exitstatus;
99512ac4 431 evalstring(trap[i], 0);
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432 exitstatus = savestatus;
433 if (i == SIGCHLD)
434 ignore_sigchld--;
435 }
436 break;
437 }
438 }
439 if (i >= NSIG)
440 break;
441 }
442 in_dotrap--;
443 pendingsigs = 0;
444}
445
446
447/*
448 * Controls whether the shell is interactive or not.
449 */
450void
451setinteractive(int on)
452{
453 static int is_interactive = -1;
454
455 if (on == is_interactive)
456 return;
457 setsignal(SIGINT);
458 setsignal(SIGQUIT);
459 setsignal(SIGTERM);
460#ifndef NO_HISTORY
461 setsignal(SIGWINCH);
462#endif
463 is_interactive = on;
464}
465
466
467/*
468 * Called to exit the shell.
469 */
470void
471exitshell(int status)
472{
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473 TRACE(("exitshell(%d) pid=%d\n", status, getpid()));
474 exiting = 1;
475 exiting_exitstatus = status;
476 exitshell_savedstatus();
477}
478
479void
480exitshell_savedstatus(void)
481{
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482 struct jmploc loc1, loc2;
483 char *p;
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484 volatile int sig = 0;
485 sigset_t sigs;
486
487 if (!exiting) {
488 if (in_dotrap && last_trapsig) {
489 sig = last_trapsig;
490 exiting_exitstatus = sig + 128;
491 } else
492 exiting_exitstatus = oexitstatus;
493 }
494 exitstatus = oexitstatus = exiting_exitstatus;
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495 if (setjmp(loc1.loc)) {
496 goto l1;
497 }
498 if (setjmp(loc2.loc)) {
499 goto l2;
500 }
501 handler = &loc1;
502 if ((p = trap[0]) != NULL && *p != '\0') {
503 trap[0] = NULL;
99512ac4 504 evalstring(p, 0);
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505 }
506l1: handler = &loc2; /* probably unnecessary */
507 flushall();
508#if JOBS
509 setjobctl(0);
510#endif
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511l2:
512 if (sig != 0 && sig != SIGSTOP && sig != SIGTSTP && sig != SIGTTIN &&
513 sig != SIGTTOU) {
514 signal(sig, SIG_DFL);
515 sigemptyset(&sigs);
516 sigaddset(&sigs, sig);
517 sigprocmask(SIG_UNBLOCK, &sigs, NULL);
518 kill(getpid(), sig);
519 /* If the default action is to ignore, fall back to _exit(). */
520 }
521 _exit(exiting_exitstatus);
984263bc 522}