2 * Copyright (c) 1991, 1993
3 * The Regents of the University of California. All rights reserved.
5 * This code is derived from software contributed to Berkeley by
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
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. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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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 */
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 static char sigmode
[NSIG
]; /* current value of signal */
75 volatile sig_atomic_t pendingsig
; /* indicates some signal received */
76 volatile sig_atomic_t pendingsig_waitcmd
; /* indicates wait builtin should be interrupted */
77 static int in_dotrap
; /* do we execute in a trap handler? */
78 static char *volatile trap
[NSIG
]; /* trap handler commands */
79 static volatile sig_atomic_t gotsig
[NSIG
];
80 /* indicates specified signal received */
81 static int ignore_sigchld
; /* Used while handling SIGCHLD traps. */
82 static int last_trapsig
;
84 static int exiting
; /* exitshell() has been called */
85 static int exiting_exitstatus
; /* value passed to exitshell() */
87 static int getsigaction(int, sig_t
*);
91 * Map a string to a signal number.
93 * Note: the signal number may exceed NSIG.
96 sigstring_to_signum(char *sig
)
103 return ((signo
>= 0 && signo
< NSIG
) ? signo
: (-1));
104 } else if (strcasecmp(sig
, "EXIT") == 0) {
109 if (strncasecmp(sig
, "SIG", 3) == 0)
111 for (n
= 1; n
< sys_nsig
; n
++)
112 if (sys_signame
[n
] &&
113 strcasecmp(sys_signame
[n
], sig
) == 0)
121 * Print a list of valid signal names.
129 for (n
= 1; n
< sys_nsig
; n
++) {
130 if (sys_signame
[n
]) {
131 out1fmt("%s", sys_signame
[n
]);
132 outlen
+= strlen(sys_signame
[n
]);
135 outlen
+= 3; /* good enough */
138 if (outlen
> 71 || n
== sys_nsig
- 1) {
152 trapcmd(int argc __unused
, char **argv
)
159 while ((i
= nextopt("l")) != '\0') {
169 for (signo
= 0 ; signo
< sys_nsig
; signo
++) {
170 if (signo
< NSIG
&& trap
[signo
] != NULL
) {
172 out1qstr(trap
[signo
]);
175 } else if (sys_signame
[signo
]) {
176 out1fmt(" %s\n", sys_signame
[signo
]);
178 out1fmt(" %d\n", signo
);
185 if (*argv
&& !is_number(*argv
)) {
186 if (strcmp(*argv
, "-") == 0)
193 for (; *argv
; argv
++) {
194 if ((signo
= sigstring_to_signum(*argv
)) == -1) {
195 warning("bad signal %s", *argv
);
201 action
= savestr(action
);
204 trap
[signo
] = action
;
214 * Clear traps on a fork.
221 for (tp
= trap
; tp
<= &trap
[NSIG
- 1] ; tp
++) {
222 if (*tp
&& **tp
) { /* trap not NULL or SIG_IGN */
227 setsignal(tp
- trap
);
235 * Check if we have any traps enabled.
242 for (tp
= trap
; tp
<= &trap
[NSIG
- 1] ; tp
++) {
243 if (*tp
&& **tp
) /* trap not NULL or SIG_IGN */
250 * Set the signal handler for the specified signal. The routine figures
251 * out what it should be set to.
257 sig_t sigact
= SIG_DFL
;
261 if ((t
= trap
[signo
]) == NULL
)
267 if (action
== S_DFL
) {
284 if (rootshell
&& iflag
)
290 if (rootshell
&& mflag
)
300 * current setting unknown
302 if (!getsigaction(signo
, &sigact
)) {
304 * Pretend it worked; maybe we should give a warning
305 * here, but other shells don't. We don't alter
306 * sigmode, so that we retry every time.
310 if (sigact
== SIG_IGN
) {
311 if (mflag
&& (signo
== SIGTSTP
||
312 signo
== SIGTTIN
|| signo
== SIGTTOU
)) {
313 *t
= S_IGN
; /* don't hard ignore these */
317 *t
= S_RESET
; /* force to be set */
320 if (*t
== S_HARD_IGN
|| *t
== action
)
323 case S_DFL
: sigact
= SIG_DFL
; break;
324 case S_CATCH
: sigact
= onsig
; break;
325 case S_IGN
: sigact
= SIG_IGN
; break;
328 sa
.sa_handler
= sigact
;
330 sigemptyset(&sa
.sa_mask
);
331 sigaction(signo
, &sa
, NULL
);
336 * Return the current setting for sig w/o changing it.
339 getsigaction(int signo
, sig_t
*sigact
)
343 if (sigaction(signo
, (struct sigaction
*)0, &sa
) == -1)
345 *sigact
= (sig_t
) sa
.sa_handler
;
357 if (sigmode
[signo
] == 0)
359 if (sigmode
[signo
] != S_IGN
&& sigmode
[signo
] != S_HARD_IGN
) {
360 signal(signo
, SIG_IGN
);
361 sigmode
[signo
] = S_IGN
;
367 issigchldtrapped(void)
370 return (trap
[SIGCHLD
] != NULL
&& *trap
[SIGCHLD
] != '\0');
381 if (signo
== SIGINT
&& trap
[SIGINT
] == NULL
) {
383 * The !in_dotrap here is safe. The only way we can arrive
384 * here with in_dotrap set is that a trap handler set SIGINT to
385 * SIG_DFL and killed itself.
387 if (suppressint
&& !in_dotrap
)
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.
415 int savestatus
, prev_evalskip
, prev_skipcount
;
420 pendingsig_waitcmd
= 0;
421 for (i
= 1; i
< NSIG
; i
++) {
426 * Ignore SIGCHLD to avoid infinite
427 * recursion if the trap action does
434 * Backup current evalskip
435 * state and reset it before
436 * executing a trap, so that the
437 * trap is not disturbed by an
438 * ongoing break/continue/return
441 prev_evalskip
= evalskip
;
442 prev_skipcount
= skipcount
;
446 savestatus
= exitstatus
;
447 evalstring(trap
[i
], 0);
450 * If such a command was not
451 * already in progress, allow a
452 * break/continue/return in the
453 * trap action to have an effect
457 prev_evalskip
!= 0) {
458 evalskip
= prev_evalskip
;
459 skipcount
= prev_skipcount
;
460 exitstatus
= savestatus
;
477 * Controls whether the shell is interactive or not.
480 setinteractive(int on
)
482 static int is_interactive
= -1;
484 if (on
== is_interactive
)
494 * Called to exit the shell.
497 exitshell(int status
)
499 TRACE(("exitshell(%d) pid=%d\n", status
, getpid()));
501 exiting_exitstatus
= status
;
502 exitshell_savedstatus();
506 exitshell_savedstatus(void)
508 struct jmploc loc1
, loc2
;
514 if (in_dotrap
&& last_trapsig
) {
516 exiting_exitstatus
= sig
+ 128;
518 exiting_exitstatus
= oexitstatus
;
520 exitstatus
= oexitstatus
= exiting_exitstatus
;
521 if (!setjmp(loc1
.loc
)) {
523 if ((p
= trap
[0]) != NULL
&& *p
!= '\0') {
525 * Reset evalskip, or the trap on EXIT could be
526 * interrupted if the last command was a "return".
533 if (!setjmp(loc2
.loc
)) {
534 handler
= &loc2
; /* probably unnecessary */
540 if (sig
!= 0 && sig
!= SIGSTOP
&& sig
!= SIGTSTP
&& sig
!= SIGTTIN
&&
542 signal(sig
, SIG_DFL
);
544 sigaddset(&sigs
, sig
);
545 sigprocmask(SIG_UNBLOCK
, &sigs
, NULL
);
547 /* If the default action is to ignore, fall back to _exit(). */
549 _exit(exiting_exitstatus
);