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Commit | Line | Data |
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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 | |
bb70624e | 10 | Software Foundation; either version 2, or (at your option) any later |
726f6388 JA |
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 | |
bb70624e | 20 | Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */ |
726f6388 | 21 | |
ccc6cda3 JA |
22 | #include "config.h" |
23 | ||
e8ce775d JA |
24 | #if defined (HAVE_UNISTD_H) |
25 | # include <unistd.h> | |
26 | #endif | |
27 | ||
726f6388 | 28 | #include "bashtypes.h" |
d166f048 | 29 | #include "bashansi.h" |
726f6388 | 30 | |
cce855bc | 31 | #include <stdio.h> |
bb70624e | 32 | #include <errno.h> |
cce855bc JA |
33 | |
34 | #include "trap.h" | |
35 | ||
726f6388 | 36 | #include "shell.h" |
bb70624e | 37 | #include "input.h" /* for save_token_state, restore_token_state */ |
726f6388 | 38 | #include "signames.h" |
ccc6cda3 | 39 | #include "builtins/common.h" |
726f6388 | 40 | |
bb70624e JA |
41 | #ifndef errno |
42 | extern int errno; | |
43 | #endif | |
44 | ||
726f6388 JA |
45 | /* Flags which describe the current handling state of a signal. */ |
46 | #define SIG_INHERITED 0x0 /* Value inherited from parent. */ | |
47 | #define SIG_TRAPPED 0x1 /* Currently trapped. */ | |
48 | #define SIG_HARD_IGNORE 0x2 /* Signal was ignored on shell entry. */ | |
49 | #define SIG_SPECIAL 0x4 /* Treat this signal specially. */ | |
50 | #define SIG_NO_TRAP 0x8 /* Signal cannot be trapped. */ | |
ccc6cda3 JA |
51 | #define SIG_INPROGRESS 0x10 /* Signal handler currently executing. */ |
52 | #define SIG_CHANGED 0x20 /* Trap value changed in trap handler. */ | |
53 | #define SIG_IGNORED 0x40 /* The signal is currently being ignored. */ | |
726f6388 JA |
54 | |
55 | /* An array of such flags, one for each signal, describing what the | |
ccc6cda3 JA |
56 | shell will do with a signal. DEBUG_TRAP == NSIG; some code below |
57 | assumes this. */ | |
58 | static int sigmodes[NSIG+1]; | |
726f6388 JA |
59 | |
60 | static void change_signal (), restore_signal (); | |
61 | ||
62 | /* Variables used here but defined in other files. */ | |
63 | extern int interactive_shell, interactive; | |
64 | extern int interrupt_immediately; | |
65 | extern int last_command_exit_value; | |
d166f048 | 66 | extern int line_number; |
726f6388 JA |
67 | |
68 | /* The list of things to do originally, before we started trapping. */ | |
69 | SigHandler *original_signals[NSIG]; | |
70 | ||
71 | /* For each signal, a slot for a string, which is a command to be | |
72 | executed when that signal is recieved. The slot can also contain | |
73 | DEFAULT_SIG, which means do whatever you were going to do before | |
74 | you were so rudely interrupted, or IGNORE_SIG, which says ignore | |
75 | this signal. */ | |
ccc6cda3 | 76 | char *trap_list[NSIG+1]; |
726f6388 JA |
77 | |
78 | /* A bitmap of signals received for which we have trap handlers. */ | |
79 | int pending_traps[NSIG]; | |
80 | ||
ccc6cda3 JA |
81 | /* Set to the number of the signal we're running the trap for + 1. |
82 | Used in execute_cmd.c and builtins/common.c to clean up when | |
83 | parse_and_execute does not return normally after executing the | |
84 | trap command (e.g., when `return' is executed in the trap command). */ | |
85 | int running_trap; | |
86 | ||
d166f048 JA |
87 | /* The value of line_number when the trap started executing, since |
88 | parse_and_execute resets it to 1 and the trap command might want | |
89 | it. */ | |
90 | int trap_line_number; | |
91 | ||
726f6388 JA |
92 | /* A value which can never be the target of a trap handler. */ |
93 | #define IMPOSSIBLE_TRAP_HANDLER (SigHandler *)initialize_traps | |
94 | ||
95 | void | |
96 | initialize_traps () | |
97 | { | |
98 | register int i; | |
99 | ||
ccc6cda3 JA |
100 | trap_list[EXIT_TRAP] = trap_list[DEBUG_TRAP] = (char *)NULL; |
101 | sigmodes[EXIT_TRAP] = sigmodes[DEBUG_TRAP] = SIG_INHERITED; | |
102 | original_signals[EXIT_TRAP] = IMPOSSIBLE_TRAP_HANDLER; | |
726f6388 JA |
103 | |
104 | for (i = 1; i < NSIG; i++) | |
105 | { | |
106 | pending_traps[i] = 0; | |
107 | trap_list[i] = (char *)DEFAULT_SIG; | |
108 | sigmodes[i] = SIG_INHERITED; | |
109 | original_signals[i] = IMPOSSIBLE_TRAP_HANDLER; | |
110 | } | |
111 | ||
112 | /* Show which signals are treated specially by the shell. */ | |
113 | #if defined (SIGCHLD) | |
ccc6cda3 JA |
114 | original_signals[SIGCHLD] = |
115 | (SigHandler *) set_signal_handler (SIGCHLD, SIG_DFL); | |
726f6388 JA |
116 | set_signal_handler (SIGCHLD, original_signals[SIGCHLD]); |
117 | sigmodes[SIGCHLD] |= (SIG_SPECIAL | SIG_NO_TRAP); | |
118 | #endif /* SIGCHLD */ | |
119 | ||
120 | original_signals[SIGINT] = | |
121 | (SigHandler *) set_signal_handler (SIGINT, SIG_DFL); | |
122 | set_signal_handler (SIGINT, original_signals[SIGINT]); | |
123 | sigmodes[SIGINT] |= SIG_SPECIAL; | |
124 | ||
b72432fd JA |
125 | #if defined (__BEOS__) |
126 | /* BeOS sets SIGINT to SIG_IGN! */ | |
127 | original_signals[SIGINT] = SIG_DFL; | |
128 | #endif | |
129 | ||
726f6388 JA |
130 | original_signals[SIGQUIT] = |
131 | (SigHandler *) set_signal_handler (SIGQUIT, SIG_DFL); | |
132 | set_signal_handler (SIGQUIT, original_signals[SIGQUIT]); | |
133 | sigmodes[SIGQUIT] |= SIG_SPECIAL; | |
134 | ||
135 | if (interactive) | |
136 | { | |
ccc6cda3 JA |
137 | original_signals[SIGTERM] = |
138 | (SigHandler *)set_signal_handler (SIGTERM, SIG_DFL); | |
726f6388 JA |
139 | set_signal_handler (SIGTERM, original_signals[SIGTERM]); |
140 | sigmodes[SIGTERM] |= SIG_SPECIAL; | |
141 | } | |
142 | } | |
143 | ||
bb70624e JA |
144 | #ifdef INCLUDE_UNUSED |
145 | /* Return a printable representation of the trap handler for SIG. */ | |
146 | static char * | |
147 | trap_handler_string (sig) | |
148 | int sig; | |
149 | { | |
150 | if (trap_list[sig] == (char *)DEFAULT_SIG) | |
151 | return "DEFAULT_SIG"; | |
152 | else if (trap_list[sig] == (char *)IGNORE_SIG) | |
153 | return "IGNORE_SIG"; | |
154 | else if (trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER) | |
155 | return "IMPOSSIBLE_TRAP_HANDLER"; | |
156 | else if (trap_list[sig]) | |
157 | return trap_list[sig]; | |
158 | else | |
159 | return "NULL"; | |
160 | } | |
161 | #endif | |
162 | ||
726f6388 JA |
163 | /* Return the print name of this signal. */ |
164 | char * | |
165 | signal_name (sig) | |
166 | int sig; | |
167 | { | |
cce855bc JA |
168 | char *ret; |
169 | ||
170 | /* on cygwin32, signal_names[sig] could be null */ | |
171 | ret = (sig > NSIG || sig < 0) ? "bad signal number" : signal_names[sig]; | |
172 | if (ret == NULL) | |
173 | ret = "unrecognized signal number"; | |
174 | return ret; | |
726f6388 JA |
175 | } |
176 | ||
177 | /* Turn a string into a signal number, or a number into | |
178 | a signal number. If STRING is "2", "SIGINT", or "INT", | |
179 | then (int)2 is returned. Return NO_SIG if STRING doesn't | |
180 | contain a valid signal descriptor. */ | |
181 | int | |
182 | decode_signal (string) | |
183 | char *string; | |
184 | { | |
ccc6cda3 | 185 | long sig; |
726f6388 | 186 | |
ccc6cda3 JA |
187 | if (legal_number (string, &sig)) |
188 | return ((sig >= 0 && sig <= NSIG) ? (int)sig : NO_SIG); | |
726f6388 | 189 | |
e8ce775d | 190 | /* A leading `SIG' may be omitted. */ |
ccc6cda3 | 191 | for (sig = 0; sig <= NSIG; sig++) |
b72432fd JA |
192 | { |
193 | if (signal_names[sig] == 0 || signal_names[sig][0] == '\0') | |
194 | continue; | |
195 | if (strcasecmp (string, signal_names[sig]) == 0 || | |
196 | (STREQN (signal_names[sig], "SIG", 3) && | |
197 | strcasecmp (string, &(signal_names[sig])[3]) == 0)) | |
198 | return ((int)sig); | |
199 | } | |
726f6388 JA |
200 | |
201 | return (NO_SIG); | |
202 | } | |
203 | ||
204 | /* Non-zero when we catch a trapped signal. */ | |
ccc6cda3 | 205 | static int catch_flag; |
726f6388 JA |
206 | |
207 | void | |
208 | run_pending_traps () | |
209 | { | |
210 | register int sig; | |
bb70624e | 211 | int old_exit_value, *token_state; |
726f6388 JA |
212 | |
213 | if (catch_flag == 0) /* simple optimization */ | |
214 | return; | |
215 | ||
216 | catch_flag = 0; | |
217 | ||
218 | /* Preserve $? when running trap. */ | |
219 | old_exit_value = last_command_exit_value; | |
220 | ||
221 | for (sig = 1; sig < NSIG; sig++) | |
222 | { | |
223 | /* XXX this could be made into a counter by using | |
224 | while (pending_traps[sig]--) instead of the if statement. */ | |
225 | if (pending_traps[sig]) | |
226 | { | |
ccc6cda3 | 227 | #if defined (HAVE_POSIX_SIGNALS) |
726f6388 JA |
228 | sigset_t set, oset; |
229 | ||
230 | sigemptyset (&set); | |
231 | sigemptyset (&oset); | |
232 | ||
233 | sigaddset (&set, sig); | |
234 | sigprocmask (SIG_BLOCK, &set, &oset); | |
235 | #else | |
236 | # if defined (HAVE_BSD_SIGNALS) | |
237 | int oldmask = sigblock (sigmask (sig)); | |
238 | # endif | |
ccc6cda3 | 239 | #endif /* HAVE_POSIX_SIGNALS */ |
726f6388 JA |
240 | |
241 | if (sig == SIGINT) | |
242 | { | |
243 | run_interrupt_trap (); | |
ccc6cda3 | 244 | CLRINTERRUPT; |
726f6388 | 245 | } |
bb70624e JA |
246 | else if (trap_list[sig] == (char *)DEFAULT_SIG || |
247 | trap_list[sig] == (char *)IGNORE_SIG || | |
248 | trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER) | |
249 | { | |
250 | /* This is possible due to a race condition. Say a bash | |
251 | process has SIGTERM trapped. A subshell is spawned | |
252 | using { list; } & and the parent does something and kills | |
253 | the subshell with SIGTERM. It's possible for the subshell | |
254 | to set pending_traps[SIGTERM] to 1 before the code in | |
255 | execute_cmd.c eventually calls restore_original_signals | |
256 | to reset the SIGTERM signal handler in the subshell. The | |
257 | next time run_pending_traps is called, pending_traps[SIGTERM] | |
258 | will be 1, but the trap handler in trap_list[SIGTERM] will | |
259 | be invalid (probably DEFAULT_SIG, but it could be IGNORE_SIG). | |
260 | Unless we catch this, the subshell will dump core when | |
261 | trap_list[SIGTERM] == DEFAULT_SIG, because DEFAULT_SIG is | |
262 | usually 0x0. */ | |
263 | internal_warning ("run_pending_traps: bad value in trap_list[%d]: 0x%x", | |
264 | sig, (int)trap_list[sig]); | |
265 | if (trap_list[sig] == (char *)DEFAULT_SIG) | |
266 | { | |
267 | internal_warning ("run_pending_traps: signal handler is SIG_DFL, resending %d (%s) to myself", sig, signal_name (sig)); | |
268 | kill (getpid (), sig); | |
269 | } | |
270 | } | |
726f6388 | 271 | else |
bb70624e JA |
272 | { |
273 | token_state = save_token_state (); | |
274 | parse_and_execute (savestring (trap_list[sig]), "trap", SEVAL_NONINT|SEVAL_NOHIST); | |
275 | restore_token_state (token_state); | |
276 | free (token_state); | |
277 | } | |
726f6388 JA |
278 | |
279 | pending_traps[sig] = 0; | |
280 | ||
ccc6cda3 | 281 | #if defined (HAVE_POSIX_SIGNALS) |
726f6388 JA |
282 | sigprocmask (SIG_SETMASK, &oset, (sigset_t *)NULL); |
283 | #else | |
284 | # if defined (HAVE_BSD_SIGNALS) | |
285 | sigsetmask (oldmask); | |
286 | # endif | |
287 | #endif /* POSIX_VERSION */ | |
288 | } | |
289 | } | |
290 | ||
291 | last_command_exit_value = old_exit_value; | |
292 | } | |
293 | ||
294 | sighandler | |
295 | trap_handler (sig) | |
296 | int sig; | |
297 | { | |
bb70624e JA |
298 | int oerrno; |
299 | ||
726f6388 JA |
300 | if ((sig >= NSIG) || |
301 | (trap_list[sig] == (char *)DEFAULT_SIG) || | |
302 | (trap_list[sig] == (char *)IGNORE_SIG)) | |
ccc6cda3 | 303 | programming_error ("trap_handler: bad signal %d", sig); |
726f6388 JA |
304 | else |
305 | { | |
bb70624e | 306 | errno = oerrno; |
ccc6cda3 | 307 | #if defined (MUST_REINSTALL_SIGHANDLERS) |
726f6388 | 308 | set_signal_handler (sig, trap_handler); |
ccc6cda3 | 309 | #endif /* MUST_REINSTALL_SIGHANDLERS */ |
726f6388 JA |
310 | |
311 | catch_flag = 1; | |
312 | pending_traps[sig]++; | |
313 | ||
314 | if (interrupt_immediately) | |
315 | run_pending_traps (); | |
bb70624e JA |
316 | |
317 | errno = oerrno; | |
726f6388 | 318 | } |
ccc6cda3 JA |
319 | |
320 | SIGRETURN (0); | |
726f6388 JA |
321 | } |
322 | ||
323 | #if defined (JOB_CONTROL) && defined (SIGCHLD) | |
cce855bc JA |
324 | |
325 | #ifdef INCLUDE_UNUSED | |
726f6388 JA |
326 | /* Make COMMAND_STRING be executed when SIGCHLD is caught. */ |
327 | void | |
328 | set_sigchld_trap (command_string) | |
329 | char *command_string; | |
330 | { | |
726f6388 JA |
331 | set_signal (SIGCHLD, command_string); |
332 | } | |
cce855bc | 333 | #endif |
726f6388 JA |
334 | |
335 | /* Make COMMAND_STRING be executed when SIGCHLD is caught iff the current | |
336 | SIGCHLD trap handler is DEFAULT_SIG. */ | |
337 | void | |
338 | maybe_set_sigchld_trap (command_string) | |
339 | char *command_string; | |
340 | { | |
726f6388 JA |
341 | if ((sigmodes[SIGCHLD] & SIG_TRAPPED) == 0) |
342 | set_signal (SIGCHLD, command_string); | |
343 | } | |
344 | #endif /* JOB_CONTROL && SIGCHLD */ | |
345 | ||
ccc6cda3 JA |
346 | void |
347 | set_debug_trap (command) | |
726f6388 JA |
348 | char *command; |
349 | { | |
ccc6cda3 JA |
350 | set_signal (DEBUG_TRAP, command); |
351 | } | |
726f6388 | 352 | |
cce855bc | 353 | #ifdef INCLUDE_UNUSED |
ccc6cda3 JA |
354 | void |
355 | set_sigint_trap (command) | |
356 | char *command; | |
357 | { | |
726f6388 JA |
358 | set_signal (SIGINT, command); |
359 | } | |
cce855bc | 360 | #endif |
726f6388 JA |
361 | |
362 | /* Reset the SIGINT handler so that subshells that are doing `shellsy' | |
363 | things, like waiting for command substitution or executing commands | |
364 | in explicit subshells ( ( cmd ) ), can catch interrupts properly. */ | |
365 | SigHandler * | |
366 | set_sigint_handler () | |
367 | { | |
368 | if (sigmodes[SIGINT] & SIG_HARD_IGNORE) | |
369 | return ((SigHandler *)SIG_IGN); | |
370 | ||
371 | else if (sigmodes[SIGINT] & SIG_IGNORED) | |
ccc6cda3 JA |
372 | return ((SigHandler *)set_signal_handler (SIGINT, SIG_IGN)); /* XXX */ |
373 | ||
726f6388 JA |
374 | else if (sigmodes[SIGINT] & SIG_TRAPPED) |
375 | return ((SigHandler *)set_signal_handler (SIGINT, trap_handler)); | |
376 | ||
377 | /* The signal is not trapped, so set the handler to the shell's special | |
378 | interrupt handler. */ | |
379 | else if (interactive) /* XXX - was interactive_shell */ | |
380 | return (set_signal_handler (SIGINT, sigint_sighandler)); | |
381 | else | |
382 | return (set_signal_handler (SIGINT, termination_unwind_protect)); | |
383 | } | |
384 | ||
e8ce775d JA |
385 | /* Return the correct handler for signal SIG according to the values in |
386 | sigmodes[SIG]. */ | |
387 | SigHandler * | |
388 | trap_to_sighandler (sig) | |
389 | int sig; | |
390 | { | |
391 | if (sigmodes[sig] & (SIG_IGNORED|SIG_HARD_IGNORE)) | |
392 | return (SIG_IGN); | |
393 | else if (sigmodes[sig] & SIG_TRAPPED) | |
394 | return (trap_handler); | |
395 | else | |
396 | return (SIG_DFL); | |
397 | } | |
398 | ||
726f6388 JA |
399 | /* Set SIG to call STRING as a command. */ |
400 | void | |
401 | set_signal (sig, string) | |
402 | int sig; | |
403 | char *string; | |
404 | { | |
ccc6cda3 JA |
405 | if (sig == DEBUG_TRAP || sig == EXIT_TRAP) |
406 | { | |
407 | change_signal (sig, savestring (string)); | |
d166f048 JA |
408 | if (sig == EXIT_TRAP && interactive == 0) |
409 | initialize_terminating_signals (); | |
ccc6cda3 JA |
410 | return; |
411 | } | |
412 | ||
726f6388 JA |
413 | /* A signal ignored on entry to the shell cannot be trapped or reset, but |
414 | no error is reported when attempting to do so. -- Posix.2 */ | |
415 | if (sigmodes[sig] & SIG_HARD_IGNORE) | |
416 | return; | |
417 | ||
418 | /* Make sure we have original_signals[sig] if the signal has not yet | |
419 | been trapped. */ | |
420 | if ((sigmodes[sig] & SIG_TRAPPED) == 0) | |
421 | { | |
422 | /* If we aren't sure of the original value, check it. */ | |
423 | if (original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) | |
424 | { | |
425 | original_signals[sig] = (SigHandler *)set_signal_handler (sig, SIG_DFL); | |
426 | set_signal_handler (sig, original_signals[sig]); | |
427 | } | |
428 | ||
429 | /* Signals ignored on entry to the shell cannot be trapped or reset. */ | |
430 | if (original_signals[sig] == SIG_IGN) | |
431 | { | |
432 | sigmodes[sig] |= SIG_HARD_IGNORE; | |
433 | return; | |
434 | } | |
435 | } | |
436 | ||
437 | /* Only change the system signal handler if SIG_NO_TRAP is not set. | |
438 | The trap command string is changed in either case. The shell signal | |
439 | handlers for SIGINT and SIGCHLD run the user specified traps in an | |
440 | environment in which it is safe to do so. */ | |
441 | if ((sigmodes[sig] & SIG_NO_TRAP) == 0) | |
442 | { | |
443 | set_signal_handler (sig, SIG_IGN); | |
444 | change_signal (sig, savestring (string)); | |
445 | set_signal_handler (sig, trap_handler); | |
446 | } | |
447 | else | |
448 | change_signal (sig, savestring (string)); | |
449 | } | |
450 | ||
451 | static void | |
452 | free_trap_command (sig) | |
453 | int sig; | |
454 | { | |
455 | if ((sigmodes[sig] & SIG_TRAPPED) && trap_list[sig] && | |
456 | (trap_list[sig] != (char *)IGNORE_SIG) && | |
457 | (trap_list[sig] != (char *)DEFAULT_SIG) && | |
458 | (trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER)) | |
459 | free (trap_list[sig]); | |
460 | } | |
ccc6cda3 | 461 | |
726f6388 JA |
462 | /* If SIG has a string assigned to it, get rid of it. Then give it |
463 | VALUE. */ | |
464 | static void | |
465 | change_signal (sig, value) | |
466 | int sig; | |
467 | char *value; | |
468 | { | |
d166f048 JA |
469 | if ((sigmodes[sig] & SIG_INPROGRESS) == 0) |
470 | free_trap_command (sig); | |
726f6388 JA |
471 | trap_list[sig] = value; |
472 | ||
473 | sigmodes[sig] |= SIG_TRAPPED; | |
474 | if (value == (char *)IGNORE_SIG) | |
475 | sigmodes[sig] |= SIG_IGNORED; | |
476 | else | |
477 | sigmodes[sig] &= ~SIG_IGNORED; | |
478 | if (sigmodes[sig] & SIG_INPROGRESS) | |
479 | sigmodes[sig] |= SIG_CHANGED; | |
480 | } | |
481 | ||
482 | #define GET_ORIGINAL_SIGNAL(sig) \ | |
483 | if (sig && sig < NSIG && original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) \ | |
484 | get_original_signal (sig) | |
485 | ||
486 | static void | |
487 | get_original_signal (sig) | |
488 | int sig; | |
489 | { | |
490 | /* If we aren't sure the of the original value, then get it. */ | |
491 | if (original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER) | |
492 | { | |
493 | original_signals[sig] = | |
494 | (SigHandler *) set_signal_handler (sig, SIG_DFL); | |
495 | set_signal_handler (sig, original_signals[sig]); | |
496 | ||
497 | /* Signals ignored on entry to the shell cannot be trapped. */ | |
498 | if (original_signals[sig] == SIG_IGN) | |
499 | sigmodes[sig] |= SIG_HARD_IGNORE; | |
500 | } | |
501 | } | |
502 | ||
503 | /* Restore the default action for SIG; i.e., the action the shell | |
504 | would have taken before you used the trap command. This is called | |
505 | from trap_builtin (), which takes care to restore the handlers for | |
506 | the signals the shell treats specially. */ | |
507 | void | |
508 | restore_default_signal (sig) | |
509 | int sig; | |
510 | { | |
ccc6cda3 | 511 | if (sig == DEBUG_TRAP || sig == EXIT_TRAP) |
726f6388 | 512 | { |
d166f048 JA |
513 | if ((sig != DEBUG_TRAP) || (sigmodes[sig] & SIG_INPROGRESS) == 0) |
514 | free_trap_command (sig); | |
726f6388 JA |
515 | trap_list[sig] = (char *)NULL; |
516 | sigmodes[sig] &= ~SIG_TRAPPED; | |
d166f048 JA |
517 | if (sigmodes[sig] & SIG_INPROGRESS) |
518 | sigmodes[sig] |= SIG_CHANGED; | |
726f6388 JA |
519 | return; |
520 | } | |
521 | ||
522 | GET_ORIGINAL_SIGNAL (sig); | |
523 | ||
524 | /* A signal ignored on entry to the shell cannot be trapped or reset, but | |
525 | no error is reported when attempting to do so. Thanks Posix.2. */ | |
526 | if (sigmodes[sig] & SIG_HARD_IGNORE) | |
527 | return; | |
528 | ||
529 | /* If we aren't trapping this signal, don't bother doing anything else. */ | |
ccc6cda3 | 530 | if ((sigmodes[sig] & SIG_TRAPPED) == 0) |
726f6388 JA |
531 | return; |
532 | ||
533 | /* Only change the signal handler for SIG if it allows it. */ | |
ccc6cda3 | 534 | if ((sigmodes[sig] & SIG_NO_TRAP) == 0) |
726f6388 JA |
535 | set_signal_handler (sig, original_signals[sig]); |
536 | ||
537 | /* Change the trap command in either case. */ | |
538 | change_signal (sig, (char *)DEFAULT_SIG); | |
539 | ||
540 | /* Mark the signal as no longer trapped. */ | |
541 | sigmodes[sig] &= ~SIG_TRAPPED; | |
542 | } | |
543 | ||
544 | /* Make this signal be ignored. */ | |
545 | void | |
546 | ignore_signal (sig) | |
547 | int sig; | |
548 | { | |
ccc6cda3 JA |
549 | if ((sig == EXIT_TRAP || sig == DEBUG_TRAP) && ((sigmodes[sig] & SIG_IGNORED) == 0)) |
550 | { | |
551 | change_signal (sig, (char *)IGNORE_SIG); | |
552 | return; | |
553 | } | |
554 | ||
726f6388 JA |
555 | GET_ORIGINAL_SIGNAL (sig); |
556 | ||
557 | /* A signal ignored on entry to the shell cannot be trapped or reset. | |
ccc6cda3 | 558 | No error is reported when the user attempts to do so. */ |
726f6388 JA |
559 | if (sigmodes[sig] & SIG_HARD_IGNORE) |
560 | return; | |
561 | ||
562 | /* If already trapped and ignored, no change necessary. */ | |
ccc6cda3 | 563 | if (sigmodes[sig] & SIG_IGNORED) |
726f6388 JA |
564 | return; |
565 | ||
566 | /* Only change the signal handler for SIG if it allows it. */ | |
ccc6cda3 | 567 | if ((sigmodes[sig] & SIG_NO_TRAP) == 0) |
726f6388 JA |
568 | set_signal_handler (sig, SIG_IGN); |
569 | ||
570 | /* Change the trap command in either case. */ | |
571 | change_signal (sig, (char *)IGNORE_SIG); | |
572 | } | |
573 | ||
574 | /* Handle the calling of "trap 0". The only sticky situation is when | |
575 | the command to be executed includes an "exit". This is why we have | |
576 | to provide our own place for top_level to jump to. */ | |
577 | int | |
578 | run_exit_trap () | |
579 | { | |
ccc6cda3 JA |
580 | char *trap_command; |
581 | int code, old_exit_value; | |
726f6388 JA |
582 | |
583 | old_exit_value = last_command_exit_value; | |
584 | ||
ccc6cda3 JA |
585 | /* Run the trap only if signal 0 is trapped and not ignored, and we are not |
586 | currently running in the trap handler (call to exit in the list of | |
587 | commands given to trap 0). */ | |
588 | if ((sigmodes[EXIT_TRAP] & SIG_TRAPPED) && | |
589 | (sigmodes[EXIT_TRAP] & (SIG_IGNORED|SIG_INPROGRESS)) == 0) | |
726f6388 | 590 | { |
ccc6cda3 JA |
591 | trap_command = savestring (trap_list[EXIT_TRAP]); |
592 | sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED; | |
593 | sigmodes[EXIT_TRAP] |= SIG_INPROGRESS; | |
726f6388 JA |
594 | |
595 | code = setjmp (top_level); | |
596 | ||
597 | if (code == 0) | |
cce855bc JA |
598 | { |
599 | reset_parser (); | |
600 | parse_and_execute (trap_command, "exit trap", SEVAL_NONINT|SEVAL_NOHIST); | |
601 | } | |
726f6388 | 602 | else if (code == EXITPROG) |
ccc6cda3 | 603 | return (last_command_exit_value); |
726f6388 JA |
604 | else |
605 | return (old_exit_value); | |
606 | } | |
607 | ||
608 | return (old_exit_value); | |
609 | } | |
610 | ||
ccc6cda3 JA |
611 | void |
612 | run_trap_cleanup (sig) | |
613 | int sig; | |
614 | { | |
615 | sigmodes[sig] &= ~(SIG_INPROGRESS|SIG_CHANGED); | |
616 | } | |
617 | ||
618 | /* Run a trap command for SIG. SIG is one of the signals the shell treats | |
619 | specially. */ | |
726f6388 | 620 | static void |
ccc6cda3 | 621 | _run_trap_internal (sig, tag) |
726f6388 | 622 | int sig; |
ccc6cda3 | 623 | char *tag; |
726f6388 | 624 | { |
ccc6cda3 | 625 | char *trap_command, *old_trap; |
bb70624e | 626 | int old_exit_value, old_line_number, *token_state; |
ccc6cda3 JA |
627 | |
628 | /* Run the trap only if SIG is trapped and not ignored, and we are not | |
629 | currently executing in the trap handler. */ | |
630 | if ((sigmodes[sig] & SIG_TRAPPED) && ((sigmodes[sig] & SIG_IGNORED) == 0) && | |
631 | (trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER) && | |
632 | ((sigmodes[sig] & SIG_INPROGRESS) == 0)) | |
633 | { | |
634 | old_trap = trap_list[sig]; | |
635 | sigmodes[sig] |= SIG_INPROGRESS; | |
636 | sigmodes[sig] &= ~SIG_CHANGED; /* just to be sure */ | |
637 | trap_command = savestring (old_trap); | |
638 | ||
639 | running_trap = sig + 1; | |
640 | old_exit_value = last_command_exit_value; | |
d166f048 JA |
641 | /* Need to copy the value of line_number because parse_and_execute |
642 | resets it to 1, and the trap command might want it. */ | |
643 | trap_line_number = line_number; | |
bb70624e JA |
644 | |
645 | token_state = save_token_state (); | |
d166f048 | 646 | parse_and_execute (trap_command, tag, SEVAL_NONINT|SEVAL_NOHIST); |
bb70624e JA |
647 | restore_token_state (token_state); |
648 | free (token_state); | |
649 | ||
ccc6cda3 JA |
650 | last_command_exit_value = old_exit_value; |
651 | running_trap = 0; | |
652 | ||
653 | sigmodes[sig] &= ~SIG_INPROGRESS; | |
654 | ||
655 | if (sigmodes[sig] & SIG_CHANGED) | |
656 | { | |
657 | free (old_trap); | |
658 | sigmodes[sig] &= ~SIG_CHANGED; | |
659 | } | |
660 | } | |
661 | } | |
662 | ||
663 | void | |
664 | run_debug_trap () | |
665 | { | |
666 | if ((sigmodes[DEBUG_TRAP] & SIG_TRAPPED) && (sigmodes[DEBUG_TRAP] & SIG_INPROGRESS) == 0) | |
667 | _run_trap_internal (DEBUG_TRAP, "debug trap"); | |
668 | } | |
669 | ||
670 | /* Run a trap set on SIGINT. This is called from throw_to_top_level (), and | |
671 | declared here to localize the trap functions. */ | |
672 | void | |
673 | run_interrupt_trap () | |
674 | { | |
675 | _run_trap_internal (SIGINT, "interrupt trap"); | |
726f6388 JA |
676 | } |
677 | ||
cce855bc | 678 | #ifdef INCLUDE_UNUSED |
726f6388 JA |
679 | /* Free all the allocated strings in the list of traps and reset the trap |
680 | values to the default. */ | |
681 | void | |
682 | free_trap_strings () | |
683 | { | |
684 | register int i; | |
685 | ||
ccc6cda3 | 686 | for (i = 0; i < NSIG+1; i++) |
726f6388 JA |
687 | { |
688 | free_trap_command (i); | |
689 | trap_list[i] = (char *)DEFAULT_SIG; | |
690 | sigmodes[i] &= ~SIG_TRAPPED; | |
691 | } | |
ccc6cda3 | 692 | trap_list[DEBUG_TRAP] = trap_list[EXIT_TRAP] = (char *)NULL; |
726f6388 | 693 | } |
cce855bc | 694 | #endif |
726f6388 JA |
695 | |
696 | /* Reset the handler for SIG to the original value. */ | |
697 | static void | |
698 | reset_signal (sig) | |
699 | int sig; | |
700 | { | |
701 | set_signal_handler (sig, original_signals[sig]); | |
702 | } | |
703 | ||
ccc6cda3 JA |
704 | /* Set the handler signal SIG to the original and free any trap |
705 | command associated with it. */ | |
706 | static void | |
707 | restore_signal (sig) | |
708 | int sig; | |
726f6388 | 709 | { |
ccc6cda3 JA |
710 | set_signal_handler (sig, original_signals[sig]); |
711 | change_signal (sig, (char *)DEFAULT_SIG); | |
712 | sigmodes[sig] &= ~SIG_TRAPPED; | |
726f6388 JA |
713 | } |
714 | ||
ccc6cda3 JA |
715 | static void |
716 | reset_or_restore_signal_handlers (reset) | |
717 | VFunction *reset; | |
726f6388 JA |
718 | { |
719 | register int i; | |
720 | ||
ccc6cda3 JA |
721 | /* Take care of the exit trap first */ |
722 | if (sigmodes[EXIT_TRAP] & SIG_TRAPPED) | |
726f6388 | 723 | { |
ccc6cda3 JA |
724 | free_trap_command (EXIT_TRAP); |
725 | trap_list[EXIT_TRAP] = (char *)NULL; | |
726 | sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED; | |
726f6388 | 727 | } |
726f6388 JA |
728 | for (i = 1; i < NSIG; i++) |
729 | { | |
ccc6cda3 | 730 | if (sigmodes[i] & SIG_TRAPPED) |
726f6388 JA |
731 | { |
732 | if (trap_list[i] == (char *)IGNORE_SIG) | |
733 | set_signal_handler (i, SIG_IGN); | |
734 | else | |
ccc6cda3 | 735 | (*reset) (i); |
726f6388 | 736 | } |
ccc6cda3 JA |
737 | else if (sigmodes[i] & SIG_SPECIAL) |
738 | (*reset) (i); | |
726f6388 JA |
739 | } |
740 | } | |
741 | ||
726f6388 | 742 | void |
ccc6cda3 | 743 | reset_signal_handlers () |
726f6388 | 744 | { |
ccc6cda3 JA |
745 | reset_or_restore_signal_handlers (reset_signal); |
746 | } | |
726f6388 | 747 | |
ccc6cda3 JA |
748 | /* Reset all trapped signals to their original values. Signals set to be |
749 | ignored with trap '' SIGNAL should be ignored, so we make sure that they | |
750 | are. Called by child processes after they are forked. */ | |
751 | void | |
752 | restore_original_signals () | |
753 | { | |
754 | reset_or_restore_signal_handlers (restore_signal); | |
726f6388 JA |
755 | } |
756 | ||
757 | /* If a trap handler exists for signal SIG, then call it; otherwise just | |
758 | return failure. */ | |
759 | int | |
760 | maybe_call_trap_handler (sig) | |
761 | int sig; | |
762 | { | |
763 | /* Call the trap handler for SIG if the signal is trapped and not ignored. */ | |
ccc6cda3 | 764 | if ((sigmodes[sig] & SIG_TRAPPED) && ((sigmodes[sig] & SIG_IGNORED) == 0)) |
726f6388 JA |
765 | { |
766 | switch (sig) | |
767 | { | |
768 | case SIGINT: | |
769 | run_interrupt_trap (); | |
770 | break; | |
ccc6cda3 | 771 | case EXIT_TRAP: |
726f6388 JA |
772 | run_exit_trap (); |
773 | break; | |
ccc6cda3 JA |
774 | case DEBUG_TRAP: |
775 | run_debug_trap (); | |
776 | break; | |
726f6388 JA |
777 | default: |
778 | trap_handler (sig); | |
779 | break; | |
780 | } | |
781 | return (1); | |
782 | } | |
783 | else | |
784 | return (0); | |
785 | } | |
786 | ||
787 | int | |
788 | signal_is_trapped (sig) | |
789 | int sig; | |
790 | { | |
791 | return (sigmodes[sig] & SIG_TRAPPED); | |
792 | } | |
793 | ||
794 | int | |
795 | signal_is_special (sig) | |
796 | int sig; | |
797 | { | |
798 | return (sigmodes[sig] & SIG_SPECIAL); | |
799 | } | |
800 | ||
801 | int | |
802 | signal_is_ignored (sig) | |
803 | int sig; | |
804 | { | |
805 | return (sigmodes[sig] & SIG_IGNORED); | |
806 | } | |
807 | ||
808 | void | |
809 | set_signal_ignored (sig) | |
810 | int sig; | |
811 | { | |
812 | sigmodes[sig] |= SIG_HARD_IGNORE; | |
ccc6cda3 | 813 | original_signals[sig] = SIG_IGN; |
726f6388 | 814 | } |