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726f6388 JA |
1 | /* trap.c -- Not the trap command, but useful functions for manipulating |
2 | those objects. The trap command is in builtins/trap.def. */ | |
3 | ||
4 | /* Copyright (C) 1987, 1991 Free Software Foundation, Inc. | |
5 | ||
6 | This file is part of GNU Bash, the Bourne Again SHell. | |
7 | ||
8 | Bash is free software; you can redistribute it and/or modify it under | |
9 | the terms of the GNU General Public License as published by the Free | |
10 | Software Foundation; either version 1, or (at your option) any later | |
11 | version. | |
12 | ||
13 | Bash is distributed in the hope that it will be useful, but WITHOUT ANY | |
14 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
16 | for more details. | |
17 | ||
18 | You should have received a copy of the GNU General Public License along | |
19 | with Bash; see the file COPYING. If not, write to the Free Software | |
20 | Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
21 | ||
ccc6cda3 JA |
22 | #include "config.h" |
23 | ||
726f6388 JA |
24 | #include <stdio.h> |
25 | ||
26 | #include "bashtypes.h" | |
27 | #include "trap.h" | |
28 | ||
29 | #if defined (HAVE_STRING_H) | |
30 | # include <string.h> | |
31 | #else /* !HAVE_STRING_H */ | |
32 | # include <strings.h> | |
33 | #endif /* !HAVE_STRING_H */ | |
34 | ||
ccc6cda3 JA |
35 | #if defined (HAVE_UNISTD_H) |
36 | # include <unistd.h> | |
37 | #endif | |
38 | ||
726f6388 JA |
39 | #include "shell.h" |
40 | #include "signames.h" | |
ccc6cda3 | 41 | #include "builtins/common.h" |
726f6388 JA |
42 | |
43 | /* Flags which describe the current handling state of a signal. */ | |
44 | #define SIG_INHERITED 0x0 /* Value inherited from parent. */ | |
45 | #define SIG_TRAPPED 0x1 /* Currently trapped. */ | |
46 | #define SIG_HARD_IGNORE 0x2 /* Signal was ignored on shell entry. */ | |
47 | #define SIG_SPECIAL 0x4 /* Treat this signal specially. */ | |
48 | #define SIG_NO_TRAP 0x8 /* Signal cannot be trapped. */ | |
ccc6cda3 JA |
49 | #define SIG_INPROGRESS 0x10 /* Signal handler currently executing. */ |
50 | #define SIG_CHANGED 0x20 /* Trap value changed in trap handler. */ | |
51 | #define SIG_IGNORED 0x40 /* The signal is currently being ignored. */ | |
726f6388 JA |
52 | |
53 | /* An array of such flags, one for each signal, describing what the | |
ccc6cda3 JA |
54 | shell will do with a signal. DEBUG_TRAP == NSIG; some code below |
55 | assumes this. */ | |
56 | static int sigmodes[NSIG+1]; | |
726f6388 JA |
57 | |
58 | static void change_signal (), restore_signal (); | |
59 | ||
60 | /* Variables used here but defined in other files. */ | |
61 | extern int interactive_shell, interactive; | |
62 | extern int interrupt_immediately; | |
63 | extern int last_command_exit_value; | |
64 | ||
65 | /* The list of things to do originally, before we started trapping. */ | |
66 | SigHandler *original_signals[NSIG]; | |
67 | ||
68 | /* For each signal, a slot for a string, which is a command to be | |
69 | executed when that signal is recieved. The slot can also contain | |
70 | DEFAULT_SIG, which means do whatever you were going to do before | |
71 | you were so rudely interrupted, or IGNORE_SIG, which says ignore | |
72 | this signal. */ | |
ccc6cda3 | 73 | char *trap_list[NSIG+1]; |
726f6388 JA |
74 | |
75 | /* A bitmap of signals received for which we have trap handlers. */ | |
76 | int pending_traps[NSIG]; | |
77 | ||
ccc6cda3 JA |
78 | /* Set to the number of the signal we're running the trap for + 1. |
79 | Used in execute_cmd.c and builtins/common.c to clean up when | |
80 | parse_and_execute does not return normally after executing the | |
81 | trap command (e.g., when `return' is executed in the trap command). */ | |
82 | int running_trap; | |
83 | ||
726f6388 JA |
84 | /* A value which can never be the target of a trap handler. */ |
85 | #define IMPOSSIBLE_TRAP_HANDLER (SigHandler *)initialize_traps | |
86 | ||
87 | void | |
88 | initialize_traps () | |
89 | { | |
90 | register int i; | |
91 | ||
ccc6cda3 JA |
92 | trap_list[EXIT_TRAP] = trap_list[DEBUG_TRAP] = (char *)NULL; |
93 | sigmodes[EXIT_TRAP] = sigmodes[DEBUG_TRAP] = SIG_INHERITED; | |
94 | original_signals[EXIT_TRAP] = IMPOSSIBLE_TRAP_HANDLER; | |
726f6388 JA |
95 | |
96 | for (i = 1; i < NSIG; i++) | |
97 | { | |
98 | pending_traps[i] = 0; | |
99 | trap_list[i] = (char *)DEFAULT_SIG; | |
100 | sigmodes[i] = SIG_INHERITED; | |
101 | original_signals[i] = IMPOSSIBLE_TRAP_HANDLER; | |
102 | } | |
103 | ||
104 | /* Show which signals are treated specially by the shell. */ | |
105 | #if defined (SIGCHLD) | |
ccc6cda3 JA |
106 | original_signals[SIGCHLD] = |
107 | (SigHandler *) set_signal_handler (SIGCHLD, SIG_DFL); | |
726f6388 JA |
108 | set_signal_handler (SIGCHLD, original_signals[SIGCHLD]); |
109 | sigmodes[SIGCHLD] |= (SIG_SPECIAL | SIG_NO_TRAP); | |
110 | #endif /* SIGCHLD */ | |
111 | ||
112 | original_signals[SIGINT] = | |
113 | (SigHandler *) set_signal_handler (SIGINT, SIG_DFL); | |
114 | set_signal_handler (SIGINT, original_signals[SIGINT]); | |
115 | sigmodes[SIGINT] |= SIG_SPECIAL; | |
116 | ||
117 | original_signals[SIGQUIT] = | |
118 | (SigHandler *) set_signal_handler (SIGQUIT, SIG_DFL); | |
119 | set_signal_handler (SIGQUIT, original_signals[SIGQUIT]); | |
120 | sigmodes[SIGQUIT] |= SIG_SPECIAL; | |
121 | ||
122 | if (interactive) | |
123 | { | |
ccc6cda3 JA |
124 | original_signals[SIGTERM] = |
125 | (SigHandler *)set_signal_handler (SIGTERM, SIG_DFL); | |
726f6388 JA |
126 | set_signal_handler (SIGTERM, original_signals[SIGTERM]); |
127 | sigmodes[SIGTERM] |= SIG_SPECIAL; | |
128 | } | |
129 | } | |
130 | ||
131 | /* Return the print name of this signal. */ | |
132 | char * | |
133 | signal_name (sig) | |
134 | int sig; | |
135 | { | |
ccc6cda3 | 136 | return ((sig > NSIG || sig < 0) ? "bad signal number" : signal_names[sig]); |
726f6388 JA |
137 | } |
138 | ||
139 | /* Turn a string into a signal number, or a number into | |
140 | a signal number. If STRING is "2", "SIGINT", or "INT", | |
141 | then (int)2 is returned. Return NO_SIG if STRING doesn't | |
142 | contain a valid signal descriptor. */ | |
143 | int | |
144 | decode_signal (string) | |
145 | char *string; | |
146 | { | |
ccc6cda3 | 147 | long sig; |
726f6388 | 148 | |
ccc6cda3 JA |
149 | if (legal_number (string, &sig)) |
150 | return ((sig >= 0 && sig <= NSIG) ? (int)sig : NO_SIG); | |
726f6388 | 151 | |
ccc6cda3 JA |
152 | for (sig = 0; sig <= NSIG; sig++) |
153 | if (strcasecmp (string, signal_names[sig]) == 0 || | |
154 | strcasecmp (string, &(signal_names[sig])[3]) == 0) | |
155 | return ((int)sig); | |
726f6388 JA |
156 | |
157 | return (NO_SIG); | |
158 | } | |
159 | ||
160 | /* Non-zero when we catch a trapped signal. */ | |
ccc6cda3 | 161 | static int catch_flag; |
726f6388 JA |
162 | |
163 | void | |
164 | run_pending_traps () | |
165 | { | |
166 | register int sig; | |
167 | int old_exit_value; | |
168 | ||
169 | if (catch_flag == 0) /* simple optimization */ | |
170 | return; | |
171 | ||
172 | catch_flag = 0; | |
173 | ||
174 | /* Preserve $? when running trap. */ | |
175 | old_exit_value = last_command_exit_value; | |
176 | ||
177 | for (sig = 1; sig < NSIG; sig++) | |
178 | { | |
179 | /* XXX this could be made into a counter by using | |
180 | while (pending_traps[sig]--) instead of the if statement. */ | |
181 | if (pending_traps[sig]) | |
182 | { | |
ccc6cda3 | 183 | #if defined (HAVE_POSIX_SIGNALS) |
726f6388 JA |
184 | sigset_t set, oset; |
185 | ||
186 | sigemptyset (&set); | |
187 | sigemptyset (&oset); | |
188 | ||
189 | sigaddset (&set, sig); | |
190 | sigprocmask (SIG_BLOCK, &set, &oset); | |
191 | #else | |
192 | # if defined (HAVE_BSD_SIGNALS) | |
193 | int oldmask = sigblock (sigmask (sig)); | |
194 | # endif | |
ccc6cda3 | 195 | #endif /* HAVE_POSIX_SIGNALS */ |
726f6388 JA |
196 | |
197 | if (sig == SIGINT) | |
198 | { | |
199 | run_interrupt_trap (); | |
ccc6cda3 | 200 | CLRINTERRUPT; |
726f6388 JA |
201 | } |
202 | else | |
203 | parse_and_execute (savestring (trap_list[sig]), "trap", 0); | |
204 | ||
205 | pending_traps[sig] = 0; | |
206 | ||
ccc6cda3 | 207 | #if defined (HAVE_POSIX_SIGNALS) |
726f6388 JA |
208 | sigprocmask (SIG_SETMASK, &oset, (sigset_t *)NULL); |
209 | #else | |
210 | # if defined (HAVE_BSD_SIGNALS) | |
211 | sigsetmask (oldmask); | |
212 | # endif | |
213 | #endif /* POSIX_VERSION */ | |
214 | } | |
215 | } | |
216 | ||
217 | last_command_exit_value = old_exit_value; | |
218 | } | |
219 | ||
220 | sighandler | |
221 | trap_handler (sig) | |
222 | int sig; | |
223 | { | |
224 | if ((sig >= NSIG) || | |
225 | (trap_list[sig] == (char *)DEFAULT_SIG) || | |
226 | (trap_list[sig] == (char *)IGNORE_SIG)) | |
ccc6cda3 | 227 | programming_error ("trap_handler: bad signal %d", sig); |
726f6388 JA |
228 | else |
229 | { | |
ccc6cda3 | 230 | #if defined (MUST_REINSTALL_SIGHANDLERS) |
726f6388 | 231 | set_signal_handler (sig, trap_handler); |
ccc6cda3 | 232 | #endif /* MUST_REINSTALL_SIGHANDLERS */ |
726f6388 JA |
233 | |
234 | catch_flag = 1; | |
235 | pending_traps[sig]++; | |
236 | ||
237 | if (interrupt_immediately) | |
238 | run_pending_traps (); | |
239 | } | |
ccc6cda3 JA |
240 | |
241 | SIGRETURN (0); | |
726f6388 JA |
242 | } |
243 | ||
244 | #if defined (JOB_CONTROL) && defined (SIGCHLD) | |
245 | /* Make COMMAND_STRING be executed when SIGCHLD is caught. */ | |
246 | void | |
247 | set_sigchld_trap (command_string) | |
248 | char *command_string; | |
249 | { | |
726f6388 JA |
250 | set_signal (SIGCHLD, command_string); |
251 | } | |
252 | ||
253 | /* Make COMMAND_STRING be executed when SIGCHLD is caught iff the current | |
254 | SIGCHLD trap handler is DEFAULT_SIG. */ | |
255 | void | |
256 | maybe_set_sigchld_trap (command_string) | |
257 | char *command_string; | |
258 | { | |
726f6388 JA |
259 | if ((sigmodes[SIGCHLD] & SIG_TRAPPED) == 0) |
260 | set_signal (SIGCHLD, command_string); | |
261 | } | |
262 | #endif /* JOB_CONTROL && SIGCHLD */ | |
263 | ||
ccc6cda3 JA |
264 | void |
265 | set_debug_trap (command) | |
726f6388 JA |
266 | char *command; |
267 | { | |
ccc6cda3 JA |
268 | set_signal (DEBUG_TRAP, command); |
269 | } | |
726f6388 | 270 | |
ccc6cda3 JA |
271 | void |
272 | set_sigint_trap (command) | |
273 | char *command; | |
274 | { | |
726f6388 JA |
275 | set_signal (SIGINT, command); |
276 | } | |
277 | ||
278 | /* Reset the SIGINT handler so that subshells that are doing `shellsy' | |
279 | things, like waiting for command substitution or executing commands | |
280 | in explicit subshells ( ( cmd ) ), can catch interrupts properly. */ | |
281 | SigHandler * | |
282 | set_sigint_handler () | |
283 | { | |
284 | if (sigmodes[SIGINT] & SIG_HARD_IGNORE) | |
285 | return ((SigHandler *)SIG_IGN); | |
286 | ||
287 | else if (sigmodes[SIGINT] & SIG_IGNORED) | |
ccc6cda3 JA |
288 | return ((SigHandler *)set_signal_handler (SIGINT, SIG_IGN)); /* XXX */ |
289 | ||
726f6388 JA |
290 | else if (sigmodes[SIGINT] & SIG_TRAPPED) |
291 | return ((SigHandler *)set_signal_handler (SIGINT, trap_handler)); | |
292 | ||
293 | /* The signal is not trapped, so set the handler to the shell's special | |
294 | interrupt handler. */ | |
295 | else if (interactive) /* XXX - was interactive_shell */ | |
296 | return (set_signal_handler (SIGINT, sigint_sighandler)); | |
297 | else | |
298 | return (set_signal_handler (SIGINT, termination_unwind_protect)); | |
299 | } | |
300 | ||
301 | /* Set SIG to call STRING as a command. */ | |
302 | void | |
303 | set_signal (sig, string) | |
304 | int sig; | |
305 | char *string; | |
306 | { | |
ccc6cda3 JA |
307 | if (sig == DEBUG_TRAP || sig == EXIT_TRAP) |
308 | { | |
309 | change_signal (sig, savestring (string)); | |
310 | return; | |
311 | } | |
312 | ||
726f6388 JA |
313 | /* A signal ignored on entry to the shell cannot be trapped or reset, but |
314 | no error is reported when attempting to do so. -- Posix.2 */ | |
315 | if (sigmodes[sig] & SIG_HARD_IGNORE) | |
316 | return; | |
317 | ||
318 | /* Make sure we have original_signals[sig] if the signal has not yet | |
319 | been trapped. */ | |
320 | if ((sigmodes[sig] & SIG_TRAPPED) == 0) | |
321 | { | |
322 | /* If we aren't sure of the original value, check it. */ | |
323 | if (original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) | |
324 | { | |
325 | original_signals[sig] = (SigHandler *)set_signal_handler (sig, SIG_DFL); | |
326 | set_signal_handler (sig, original_signals[sig]); | |
327 | } | |
328 | ||
329 | /* Signals ignored on entry to the shell cannot be trapped or reset. */ | |
330 | if (original_signals[sig] == SIG_IGN) | |
331 | { | |
332 | sigmodes[sig] |= SIG_HARD_IGNORE; | |
333 | return; | |
334 | } | |
335 | } | |
336 | ||
337 | /* Only change the system signal handler if SIG_NO_TRAP is not set. | |
338 | The trap command string is changed in either case. The shell signal | |
339 | handlers for SIGINT and SIGCHLD run the user specified traps in an | |
340 | environment in which it is safe to do so. */ | |
341 | if ((sigmodes[sig] & SIG_NO_TRAP) == 0) | |
342 | { | |
343 | set_signal_handler (sig, SIG_IGN); | |
344 | change_signal (sig, savestring (string)); | |
345 | set_signal_handler (sig, trap_handler); | |
346 | } | |
347 | else | |
348 | change_signal (sig, savestring (string)); | |
349 | } | |
350 | ||
351 | static void | |
352 | free_trap_command (sig) | |
353 | int sig; | |
354 | { | |
355 | if ((sigmodes[sig] & SIG_TRAPPED) && trap_list[sig] && | |
356 | (trap_list[sig] != (char *)IGNORE_SIG) && | |
357 | (trap_list[sig] != (char *)DEFAULT_SIG) && | |
358 | (trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER)) | |
359 | free (trap_list[sig]); | |
360 | } | |
ccc6cda3 | 361 | |
726f6388 JA |
362 | /* If SIG has a string assigned to it, get rid of it. Then give it |
363 | VALUE. */ | |
364 | static void | |
365 | change_signal (sig, value) | |
366 | int sig; | |
367 | char *value; | |
368 | { | |
369 | free_trap_command (sig); | |
370 | trap_list[sig] = value; | |
371 | ||
372 | sigmodes[sig] |= SIG_TRAPPED; | |
373 | if (value == (char *)IGNORE_SIG) | |
374 | sigmodes[sig] |= SIG_IGNORED; | |
375 | else | |
376 | sigmodes[sig] &= ~SIG_IGNORED; | |
377 | if (sigmodes[sig] & SIG_INPROGRESS) | |
378 | sigmodes[sig] |= SIG_CHANGED; | |
379 | } | |
380 | ||
381 | #define GET_ORIGINAL_SIGNAL(sig) \ | |
382 | if (sig && sig < NSIG && original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) \ | |
383 | get_original_signal (sig) | |
384 | ||
385 | static void | |
386 | get_original_signal (sig) | |
387 | int sig; | |
388 | { | |
389 | /* If we aren't sure the of the original value, then get it. */ | |
390 | if (original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER) | |
391 | { | |
392 | original_signals[sig] = | |
393 | (SigHandler *) set_signal_handler (sig, SIG_DFL); | |
394 | set_signal_handler (sig, original_signals[sig]); | |
395 | ||
396 | /* Signals ignored on entry to the shell cannot be trapped. */ | |
397 | if (original_signals[sig] == SIG_IGN) | |
398 | sigmodes[sig] |= SIG_HARD_IGNORE; | |
399 | } | |
400 | } | |
401 | ||
402 | /* Restore the default action for SIG; i.e., the action the shell | |
403 | would have taken before you used the trap command. This is called | |
404 | from trap_builtin (), which takes care to restore the handlers for | |
405 | the signals the shell treats specially. */ | |
406 | void | |
407 | restore_default_signal (sig) | |
408 | int sig; | |
409 | { | |
ccc6cda3 | 410 | if (sig == DEBUG_TRAP || sig == EXIT_TRAP) |
726f6388 JA |
411 | { |
412 | free_trap_command (sig); | |
413 | trap_list[sig] = (char *)NULL; | |
414 | sigmodes[sig] &= ~SIG_TRAPPED; | |
415 | return; | |
416 | } | |
417 | ||
418 | GET_ORIGINAL_SIGNAL (sig); | |
419 | ||
420 | /* A signal ignored on entry to the shell cannot be trapped or reset, but | |
421 | no error is reported when attempting to do so. Thanks Posix.2. */ | |
422 | if (sigmodes[sig] & SIG_HARD_IGNORE) | |
423 | return; | |
424 | ||
425 | /* If we aren't trapping this signal, don't bother doing anything else. */ | |
ccc6cda3 | 426 | if ((sigmodes[sig] & SIG_TRAPPED) == 0) |
726f6388 JA |
427 | return; |
428 | ||
429 | /* Only change the signal handler for SIG if it allows it. */ | |
ccc6cda3 | 430 | if ((sigmodes[sig] & SIG_NO_TRAP) == 0) |
726f6388 JA |
431 | set_signal_handler (sig, original_signals[sig]); |
432 | ||
433 | /* Change the trap command in either case. */ | |
434 | change_signal (sig, (char *)DEFAULT_SIG); | |
435 | ||
436 | /* Mark the signal as no longer trapped. */ | |
437 | sigmodes[sig] &= ~SIG_TRAPPED; | |
438 | } | |
439 | ||
440 | /* Make this signal be ignored. */ | |
441 | void | |
442 | ignore_signal (sig) | |
443 | int sig; | |
444 | { | |
ccc6cda3 JA |
445 | if ((sig == EXIT_TRAP || sig == DEBUG_TRAP) && ((sigmodes[sig] & SIG_IGNORED) == 0)) |
446 | { | |
447 | change_signal (sig, (char *)IGNORE_SIG); | |
448 | return; | |
449 | } | |
450 | ||
726f6388 JA |
451 | GET_ORIGINAL_SIGNAL (sig); |
452 | ||
453 | /* A signal ignored on entry to the shell cannot be trapped or reset. | |
ccc6cda3 | 454 | No error is reported when the user attempts to do so. */ |
726f6388 JA |
455 | if (sigmodes[sig] & SIG_HARD_IGNORE) |
456 | return; | |
457 | ||
458 | /* If already trapped and ignored, no change necessary. */ | |
ccc6cda3 | 459 | if (sigmodes[sig] & SIG_IGNORED) |
726f6388 JA |
460 | return; |
461 | ||
462 | /* Only change the signal handler for SIG if it allows it. */ | |
ccc6cda3 | 463 | if ((sigmodes[sig] & SIG_NO_TRAP) == 0) |
726f6388 JA |
464 | set_signal_handler (sig, SIG_IGN); |
465 | ||
466 | /* Change the trap command in either case. */ | |
467 | change_signal (sig, (char *)IGNORE_SIG); | |
468 | } | |
469 | ||
470 | /* Handle the calling of "trap 0". The only sticky situation is when | |
471 | the command to be executed includes an "exit". This is why we have | |
472 | to provide our own place for top_level to jump to. */ | |
473 | int | |
474 | run_exit_trap () | |
475 | { | |
ccc6cda3 JA |
476 | char *trap_command; |
477 | int code, old_exit_value; | |
726f6388 JA |
478 | |
479 | old_exit_value = last_command_exit_value; | |
480 | ||
ccc6cda3 JA |
481 | /* Run the trap only if signal 0 is trapped and not ignored, and we are not |
482 | currently running in the trap handler (call to exit in the list of | |
483 | commands given to trap 0). */ | |
484 | if ((sigmodes[EXIT_TRAP] & SIG_TRAPPED) && | |
485 | (sigmodes[EXIT_TRAP] & (SIG_IGNORED|SIG_INPROGRESS)) == 0) | |
726f6388 | 486 | { |
ccc6cda3 JA |
487 | trap_command = savestring (trap_list[EXIT_TRAP]); |
488 | sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED; | |
489 | sigmodes[EXIT_TRAP] |= SIG_INPROGRESS; | |
726f6388 JA |
490 | |
491 | code = setjmp (top_level); | |
492 | ||
493 | if (code == 0) | |
ccc6cda3 | 494 | parse_and_execute (trap_command, "exit trap", 0); |
726f6388 | 495 | else if (code == EXITPROG) |
ccc6cda3 | 496 | return (last_command_exit_value); |
726f6388 JA |
497 | else |
498 | return (old_exit_value); | |
499 | } | |
500 | ||
501 | return (old_exit_value); | |
502 | } | |
503 | ||
ccc6cda3 JA |
504 | void |
505 | run_trap_cleanup (sig) | |
506 | int sig; | |
507 | { | |
508 | sigmodes[sig] &= ~(SIG_INPROGRESS|SIG_CHANGED); | |
509 | } | |
510 | ||
511 | /* Run a trap command for SIG. SIG is one of the signals the shell treats | |
512 | specially. */ | |
726f6388 | 513 | static void |
ccc6cda3 | 514 | _run_trap_internal (sig, tag) |
726f6388 | 515 | int sig; |
ccc6cda3 | 516 | char *tag; |
726f6388 | 517 | { |
ccc6cda3 JA |
518 | char *trap_command, *old_trap; |
519 | int old_exit_value; | |
520 | ||
521 | /* Run the trap only if SIG is trapped and not ignored, and we are not | |
522 | currently executing in the trap handler. */ | |
523 | if ((sigmodes[sig] & SIG_TRAPPED) && ((sigmodes[sig] & SIG_IGNORED) == 0) && | |
524 | (trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER) && | |
525 | ((sigmodes[sig] & SIG_INPROGRESS) == 0)) | |
526 | { | |
527 | old_trap = trap_list[sig]; | |
528 | sigmodes[sig] |= SIG_INPROGRESS; | |
529 | sigmodes[sig] &= ~SIG_CHANGED; /* just to be sure */ | |
530 | trap_command = savestring (old_trap); | |
531 | ||
532 | running_trap = sig + 1; | |
533 | old_exit_value = last_command_exit_value; | |
534 | parse_and_execute (trap_command, tag, 0); | |
535 | last_command_exit_value = old_exit_value; | |
536 | running_trap = 0; | |
537 | ||
538 | sigmodes[sig] &= ~SIG_INPROGRESS; | |
539 | ||
540 | if (sigmodes[sig] & SIG_CHANGED) | |
541 | { | |
542 | free (old_trap); | |
543 | sigmodes[sig] &= ~SIG_CHANGED; | |
544 | } | |
545 | } | |
546 | } | |
547 | ||
548 | void | |
549 | run_debug_trap () | |
550 | { | |
551 | if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && (sigmodes[DEBUG_TRAP] & SIG_INPROGRESS) == 0) | |
552 | _run_trap_internal (DEBUG_TRAP, "debug trap"); | |
553 | } | |
554 | ||
555 | /* Run a trap set on SIGINT. This is called from throw_to_top_level (), and | |
556 | declared here to localize the trap functions. */ | |
557 | void | |
558 | run_interrupt_trap () | |
559 | { | |
560 | _run_trap_internal (SIGINT, "interrupt trap"); | |
726f6388 JA |
561 | } |
562 | ||
563 | /* Free all the allocated strings in the list of traps and reset the trap | |
564 | values to the default. */ | |
565 | void | |
566 | free_trap_strings () | |
567 | { | |
568 | register int i; | |
569 | ||
ccc6cda3 | 570 | for (i = 0; i < NSIG+1; i++) |
726f6388 JA |
571 | { |
572 | free_trap_command (i); | |
573 | trap_list[i] = (char *)DEFAULT_SIG; | |
574 | sigmodes[i] &= ~SIG_TRAPPED; | |
575 | } | |
ccc6cda3 | 576 | trap_list[DEBUG_TRAP] = trap_list[EXIT_TRAP] = (char *)NULL; |
726f6388 JA |
577 | } |
578 | ||
579 | /* Reset the handler for SIG to the original value. */ | |
580 | static void | |
581 | reset_signal (sig) | |
582 | int sig; | |
583 | { | |
584 | set_signal_handler (sig, original_signals[sig]); | |
585 | } | |
586 | ||
ccc6cda3 JA |
587 | /* Set the handler signal SIG to the original and free any trap |
588 | command associated with it. */ | |
589 | static void | |
590 | restore_signal (sig) | |
591 | int sig; | |
726f6388 | 592 | { |
ccc6cda3 JA |
593 | set_signal_handler (sig, original_signals[sig]); |
594 | change_signal (sig, (char *)DEFAULT_SIG); | |
595 | sigmodes[sig] &= ~SIG_TRAPPED; | |
726f6388 JA |
596 | } |
597 | ||
ccc6cda3 JA |
598 | static void |
599 | reset_or_restore_signal_handlers (reset) | |
600 | VFunction *reset; | |
726f6388 JA |
601 | { |
602 | register int i; | |
603 | ||
ccc6cda3 JA |
604 | /* Take care of the exit trap first */ |
605 | if (sigmodes[EXIT_TRAP] & SIG_TRAPPED) | |
726f6388 | 606 | { |
ccc6cda3 JA |
607 | free_trap_command (EXIT_TRAP); |
608 | trap_list[EXIT_TRAP] = (char *)NULL; | |
609 | sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED; | |
726f6388 | 610 | } |
726f6388 JA |
611 | for (i = 1; i < NSIG; i++) |
612 | { | |
ccc6cda3 | 613 | if (sigmodes[i] & SIG_TRAPPED) |
726f6388 JA |
614 | { |
615 | if (trap_list[i] == (char *)IGNORE_SIG) | |
616 | set_signal_handler (i, SIG_IGN); | |
617 | else | |
ccc6cda3 | 618 | (*reset) (i); |
726f6388 | 619 | } |
ccc6cda3 JA |
620 | else if (sigmodes[i] & SIG_SPECIAL) |
621 | (*reset) (i); | |
726f6388 JA |
622 | } |
623 | } | |
624 | ||
726f6388 | 625 | void |
ccc6cda3 | 626 | reset_signal_handlers () |
726f6388 | 627 | { |
ccc6cda3 JA |
628 | reset_or_restore_signal_handlers (reset_signal); |
629 | } | |
726f6388 | 630 | |
ccc6cda3 JA |
631 | /* Reset all trapped signals to their original values. Signals set to be |
632 | ignored with trap '' SIGNAL should be ignored, so we make sure that they | |
633 | are. Called by child processes after they are forked. */ | |
634 | void | |
635 | restore_original_signals () | |
636 | { | |
637 | reset_or_restore_signal_handlers (restore_signal); | |
726f6388 JA |
638 | } |
639 | ||
640 | /* If a trap handler exists for signal SIG, then call it; otherwise just | |
641 | return failure. */ | |
642 | int | |
643 | maybe_call_trap_handler (sig) | |
644 | int sig; | |
645 | { | |
646 | /* Call the trap handler for SIG if the signal is trapped and not ignored. */ | |
ccc6cda3 | 647 | if ((sigmodes[sig] & SIG_TRAPPED) && ((sigmodes[sig] & SIG_IGNORED) == 0)) |
726f6388 JA |
648 | { |
649 | switch (sig) | |
650 | { | |
651 | case SIGINT: | |
652 | run_interrupt_trap (); | |
653 | break; | |
ccc6cda3 | 654 | case EXIT_TRAP: |
726f6388 JA |
655 | run_exit_trap (); |
656 | break; | |
ccc6cda3 JA |
657 | case DEBUG_TRAP: |
658 | run_debug_trap (); | |
659 | break; | |
726f6388 JA |
660 | default: |
661 | trap_handler (sig); | |
662 | break; | |
663 | } | |
664 | return (1); | |
665 | } | |
666 | else | |
667 | return (0); | |
668 | } | |
669 | ||
670 | int | |
671 | signal_is_trapped (sig) | |
672 | int sig; | |
673 | { | |
674 | return (sigmodes[sig] & SIG_TRAPPED); | |
675 | } | |
676 | ||
677 | int | |
678 | signal_is_special (sig) | |
679 | int sig; | |
680 | { | |
681 | return (sigmodes[sig] & SIG_SPECIAL); | |
682 | } | |
683 | ||
684 | int | |
685 | signal_is_ignored (sig) | |
686 | int sig; | |
687 | { | |
688 | return (sigmodes[sig] & SIG_IGNORED); | |
689 | } | |
690 | ||
691 | void | |
692 | set_signal_ignored (sig) | |
693 | int sig; | |
694 | { | |
695 | sigmodes[sig] |= SIG_HARD_IGNORE; | |
ccc6cda3 | 696 | original_signals[sig] = SIG_IGN; |
726f6388 | 697 | } |