2 * SPDX-License-Identifier: BSD-3-Clause
4 * Copyright (c) 1991, 1993
5 * The Regents of the University of California. All rights reserved.
7 * This code is derived from software contributed to Berkeley by
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 static char sccsid
[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95";
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD: head/bin/sh/trap.c 364919 2020-08-28 15:35:45Z jilles $");
49 #include "nodes.h" /* for other headers */
62 #include "myhistedit.h"
67 * Sigmode records the current value of the signal handlers for the various
68 * modes. A value of zero means that the current handler is not known.
69 * S_HARD_IGN indicates that the signal was ignored on entry to the shell,
72 #define S_DFL 1 /* default signal handling (SIG_DFL) */
73 #define S_CATCH 2 /* signal is caught */
74 #define S_IGN 3 /* signal is ignored (SIG_IGN) */
75 #define S_HARD_IGN 4 /* signal is ignored permanently */
76 #define S_RESET 5 /* temporary - to reset a hard ignored sig */
79 static char sigmode
[NSIG
]; /* current value of signal */
80 volatile sig_atomic_t pendingsig
; /* indicates some signal received */
81 volatile sig_atomic_t pendingsig_waitcmd
; /* indicates wait builtin should be interrupted */
82 static int in_dotrap
; /* do we execute in a trap handler? */
83 static char *volatile trap
[NSIG
]; /* trap handler commands */
84 static volatile sig_atomic_t gotsig
[NSIG
];
85 /* indicates specified signal received */
86 static int ignore_sigchld
; /* Used while handling SIGCHLD traps. */
87 static int last_trapsig
;
89 static int exiting
; /* exitshell() has been called */
90 static int exiting_exitstatus
; /* value passed to exitshell() */
92 static int getsigaction(int, sig_t
*);
96 * Map a string to a signal number.
98 * Note: the signal number may exceed NSIG.
101 sigstring_to_signum(char *sig
)
104 if (is_number(sig
)) {
108 return ((signo
>= 0 && signo
< NSIG
) ? signo
: (-1));
109 } else if (strcasecmp(sig
, "EXIT") == 0) {
114 if (strncasecmp(sig
, "SIG", 3) == 0)
116 for (n
= 1; n
< sys_nsig
; n
++)
117 if (sys_signame
[n
] &&
118 strcasecmp(sys_signame
[n
], sig
) == 0)
126 * Print a list of valid signal names.
134 for (n
= 1; n
< sys_nsig
; n
++) {
135 if (sys_signame
[n
]) {
136 out1fmt("%s", sys_signame
[n
]);
137 outlen
+= strlen(sys_signame
[n
]);
140 outlen
+= 3; /* good enough */
143 if (outlen
> 71 || n
== sys_nsig
- 1) {
157 trapcmd(int argc __unused
, char **argv
)
164 while ((i
= nextopt("l")) != '\0') {
174 for (signo
= 0 ; signo
< sys_nsig
; signo
++) {
175 if (signo
< NSIG
&& trap
[signo
] != NULL
) {
177 out1qstr(trap
[signo
]);
180 } else if (sys_signame
[signo
]) {
181 out1fmt(" %s\n", sys_signame
[signo
]);
183 out1fmt(" %d\n", signo
);
190 if (*argv
&& !is_number(*argv
)) {
191 if (strcmp(*argv
, "-") == 0)
198 for (; *argv
; argv
++) {
199 if ((signo
= sigstring_to_signum(*argv
)) == -1) {
200 warning("bad signal %s", *argv
);
206 action
= savestr(action
);
209 trap
[signo
] = action
;
219 * Clear traps on a fork.
226 for (tp
= trap
; tp
<= &trap
[NSIG
- 1] ; tp
++) {
227 if (*tp
&& **tp
) { /* trap not NULL or SIG_IGN */
232 setsignal(tp
- trap
);
240 * Check if we have any traps enabled.
247 for (tp
= trap
; tp
<= &trap
[NSIG
- 1] ; tp
++) {
248 if (*tp
&& **tp
) /* trap not NULL or SIG_IGN */
255 * Set the signal handler for the specified signal. The routine figures
256 * out what it should be set to.
262 sig_t sigact
= SIG_DFL
;
266 if ((t
= trap
[signo
]) == NULL
)
272 if (action
== S_DFL
) {
289 if (rootshell
&& iflag
)
295 if (rootshell
&& mflag
)
305 * current setting unknown
307 if (!getsigaction(signo
, &sigact
)) {
309 * Pretend it worked; maybe we should give a warning
310 * here, but other shells don't. We don't alter
311 * sigmode, so that we retry every time.
315 if (sigact
== SIG_IGN
) {
316 if (mflag
&& (signo
== SIGTSTP
||
317 signo
== SIGTTIN
|| signo
== SIGTTOU
)) {
318 *t
= S_IGN
; /* don't hard ignore these */
322 *t
= S_RESET
; /* force to be set */
325 if (*t
== S_HARD_IGN
|| *t
== action
)
328 case S_DFL
: sigact
= SIG_DFL
; break;
329 case S_CATCH
: sigact
= onsig
; break;
330 case S_IGN
: sigact
= SIG_IGN
; break;
333 sa
.sa_handler
= sigact
;
335 sigemptyset(&sa
.sa_mask
);
336 sigaction(signo
, &sa
, NULL
);
341 * Return the current setting for sig w/o changing it.
344 getsigaction(int signo
, sig_t
*sigact
)
348 if (sigaction(signo
, (struct sigaction
*)0, &sa
) == -1)
350 *sigact
= (sig_t
) sa
.sa_handler
;
362 if (sigmode
[signo
] == 0)
364 if (sigmode
[signo
] != S_IGN
&& sigmode
[signo
] != S_HARD_IGN
) {
365 signal(signo
, SIG_IGN
);
366 sigmode
[signo
] = S_IGN
;
372 issigchldtrapped(void)
375 return (trap
[SIGCHLD
] != NULL
&& *trap
[SIGCHLD
] != '\0');
386 if (signo
== SIGINT
&& trap
[SIGINT
] == NULL
) {
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.
414 struct stackmark smark
;
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 setstackmark(&smark
);
449 evalstring(stsavestr(trap
[i
]), 0);
450 popstackmark(&smark
);
453 * If such a command was not
454 * already in progress, allow a
455 * break/continue/return in the
456 * trap action to have an effect
460 prev_evalskip
!= 0) {
461 evalskip
= prev_evalskip
;
462 skipcount
= prev_skipcount
;
463 exitstatus
= savestatus
;
488 * Controls whether the shell is interactive or not based on iflag.
498 * Called to exit the shell.
501 exitshell(int status
)
503 TRACE(("exitshell(%d) pid=%d\n", status
, getpid()));
505 exiting_exitstatus
= status
;
506 exitshell_savedstatus();
510 exitshell_savedstatus(void)
512 struct jmploc loc1
, loc2
;
518 if (in_dotrap
&& last_trapsig
) {
520 exiting_exitstatus
= sig
+ 128;
522 exiting_exitstatus
= oexitstatus
;
524 exitstatus
= oexitstatus
= exiting_exitstatus
;
525 if (!setjmp(loc1
.loc
)) {
527 if ((p
= trap
[0]) != NULL
&& *p
!= '\0') {
529 * Reset evalskip, or the trap on EXIT could be
530 * interrupted if the last command was a "return".
538 if (!setjmp(loc2
.loc
)) {
539 handler
= &loc2
; /* probably unnecessary */
546 if (sig
!= 0 && sig
!= SIGSTOP
&& sig
!= SIGTSTP
&& sig
!= SIGTTIN
&&
548 signal(sig
, SIG_DFL
);
550 sigaddset(&sigs
, sig
);
551 sigprocmask(SIG_UNBLOCK
, &sigs
, NULL
);
553 /* If the default action is to ignore, fall back to _exit(). */
555 _exit(exiting_exitstatus
);