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ccc6cda3 JA |
1 | /* sig.c - interface for shell signal handlers and signal initialization. */ |
2 | ||
3 | /* Copyright (C) 1994 Free Software Foundation, Inc. | |
4 | ||
5 | This file is part of GNU Bash, the Bourne Again SHell. | |
6 | ||
7 | Bash is free software; you can redistribute it and/or modify it under | |
8 | the terms of the GNU General Public License as published by the Free | |
9 | Software Foundation; either version 2, or (at your option) any later | |
10 | version. | |
11 | ||
12 | Bash is distributed in the hope that it will be useful, but WITHOUT ANY | |
13 | WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
14 | FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
15 | for more details. | |
16 | ||
17 | You should have received a copy of the GNU General Public License along | |
18 | with Bash; see the file COPYING. If not, write to the Free Software | |
bb70624e | 19 | Foundation, 59 Temple Place, Suite 330, Boston, MA 02111 USA. */ |
ccc6cda3 JA |
20 | |
21 | #include "config.h" | |
22 | ||
23 | #include "bashtypes.h" | |
24 | ||
25 | #if defined (HAVE_UNISTD_H) | |
cce855bc JA |
26 | # ifdef _MINIX |
27 | # include <sys/types.h> | |
28 | # endif | |
ccc6cda3 JA |
29 | # include <unistd.h> |
30 | #endif | |
31 | ||
32 | #include <stdio.h> | |
33 | #include <signal.h> | |
34 | ||
35 | #include "shell.h" | |
36 | #if defined (JOB_CONTROL) | |
37 | #include "jobs.h" | |
38 | #endif /* JOB_CONTROL */ | |
39 | #include "siglist.h" | |
40 | #include "sig.h" | |
41 | #include "trap.h" | |
42 | ||
43 | #include "builtins/common.h" | |
44 | ||
45 | #if defined (READLINE) | |
46 | # include "bashline.h" | |
47 | #endif | |
48 | ||
49 | #if defined (HISTORY) | |
50 | # include "bashhist.h" | |
51 | #endif | |
52 | ||
53 | extern int last_command_exit_value; | |
54 | extern int return_catch_flag; | |
55 | extern int loop_level, continuing, breaking; | |
56 | extern int parse_and_execute_level, shell_initialized; | |
57 | extern int interactive, interactive_shell, login_shell, startup_state; | |
58 | ||
59 | /* Non-zero after SIGINT. */ | |
60 | int interrupt_state; | |
61 | ||
62 | /* The environment at the top-level R-E loop. We use this in | |
63 | the case of error return. */ | |
64 | procenv_t top_level; | |
65 | ||
66 | #if defined (JOB_CONTROL) || defined (HAVE_POSIX_SIGNALS) | |
67 | /* The signal masks that this shell runs with. */ | |
68 | sigset_t top_level_mask; | |
69 | #endif /* JOB_CONTROL */ | |
70 | ||
71 | /* When non-zero, we throw_to_top_level (). */ | |
72 | int interrupt_immediately = 0; | |
73 | ||
d166f048 | 74 | static void initialize_shell_signals (); |
ccc6cda3 JA |
75 | |
76 | void | |
77 | initialize_signals () | |
78 | { | |
d166f048 | 79 | initialize_shell_signals (); |
ccc6cda3 | 80 | initialize_job_signals (); |
e8ce775d | 81 | #if !defined (HAVE_SYS_SIGLIST) && !defined (HAVE_UNDER_SYS_SIGLIST) && !defined (HAVE_STRSIGNAL) |
ccc6cda3 | 82 | initialize_siglist (); |
e8ce775d | 83 | #endif /* !HAVE_SYS_SIGLIST && !HAVE_UNDER_SYS_SIGLIST && !HAVE_STRSIGNAL */ |
ccc6cda3 JA |
84 | } |
85 | ||
86 | void | |
87 | reinitialize_signals () | |
88 | { | |
d166f048 | 89 | initialize_shell_signals (1); |
ccc6cda3 JA |
90 | initialize_job_signals (); |
91 | } | |
92 | ||
93 | /* A structure describing a signal that terminates the shell if not | |
94 | caught. The orig_handler member is present so children can reset | |
95 | these signals back to their original handlers. */ | |
96 | struct termsig { | |
97 | int signum; | |
98 | SigHandler *orig_handler; | |
99 | }; | |
100 | ||
101 | #define NULL_HANDLER (SigHandler *)SIG_DFL | |
102 | ||
103 | /* The list of signals that would terminate the shell if not caught. | |
104 | We catch them, but just so that we can write the history file, | |
105 | and so forth. */ | |
106 | static struct termsig terminating_signals[] = { | |
107 | #ifdef SIGHUP | |
108 | SIGHUP, NULL_HANDLER, | |
109 | #endif | |
110 | ||
111 | #ifdef SIGINT | |
112 | SIGINT, NULL_HANDLER, | |
113 | #endif | |
114 | ||
115 | #ifdef SIGILL | |
116 | SIGILL, NULL_HANDLER, | |
117 | #endif | |
118 | ||
119 | #ifdef SIGTRAP | |
120 | SIGTRAP, NULL_HANDLER, | |
121 | #endif | |
122 | ||
123 | #ifdef SIGIOT | |
124 | SIGIOT, NULL_HANDLER, | |
125 | #endif | |
126 | ||
127 | #ifdef SIGDANGER | |
128 | SIGDANGER, NULL_HANDLER, | |
129 | #endif | |
130 | ||
131 | #ifdef SIGEMT | |
132 | SIGEMT, NULL_HANDLER, | |
133 | #endif | |
134 | ||
135 | #ifdef SIGFPE | |
136 | SIGFPE, NULL_HANDLER, | |
137 | #endif | |
138 | ||
139 | #ifdef SIGBUS | |
140 | SIGBUS, NULL_HANDLER, | |
141 | #endif | |
142 | ||
143 | #ifdef SIGSEGV | |
144 | SIGSEGV, NULL_HANDLER, | |
145 | #endif | |
146 | ||
147 | #ifdef SIGSYS | |
148 | SIGSYS, NULL_HANDLER, | |
149 | #endif | |
150 | ||
151 | #ifdef SIGPIPE | |
152 | SIGPIPE, NULL_HANDLER, | |
153 | #endif | |
154 | ||
155 | #ifdef SIGALRM | |
156 | SIGALRM, NULL_HANDLER, | |
157 | #endif | |
158 | ||
159 | #ifdef SIGTERM | |
160 | SIGTERM, NULL_HANDLER, | |
161 | #endif | |
162 | ||
163 | #ifdef SIGXCPU | |
164 | SIGXCPU, NULL_HANDLER, | |
165 | #endif | |
166 | ||
167 | #ifdef SIGXFSZ | |
168 | SIGXFSZ, NULL_HANDLER, | |
169 | #endif | |
170 | ||
171 | #ifdef SIGVTALRM | |
172 | SIGVTALRM, NULL_HANDLER, | |
173 | #endif | |
174 | ||
bb70624e | 175 | #if 0 |
ccc6cda3 JA |
176 | #ifdef SIGPROF |
177 | SIGPROF, NULL_HANDLER, | |
178 | #endif | |
bb70624e | 179 | #endif |
ccc6cda3 JA |
180 | |
181 | #ifdef SIGLOST | |
182 | SIGLOST, NULL_HANDLER, | |
183 | #endif | |
184 | ||
185 | #ifdef SIGUSR1 | |
186 | SIGUSR1, NULL_HANDLER, | |
187 | #endif | |
188 | ||
189 | #ifdef SIGUSR2 | |
190 | SIGUSR2, NULL_HANDLER, | |
191 | #endif | |
192 | }; | |
193 | ||
194 | #define TERMSIGS_LENGTH (sizeof (terminating_signals) / sizeof (struct termsig)) | |
195 | ||
196 | #define XSIG(x) (terminating_signals[x].signum) | |
197 | #define XHANDLER(x) (terminating_signals[x].orig_handler) | |
198 | ||
d166f048 JA |
199 | static int termsigs_initialized = 0; |
200 | ||
ccc6cda3 | 201 | /* Initialize signals that will terminate the shell to do some |
d166f048 JA |
202 | unwind protection. For non-interactive shells, we only call |
203 | this when a trap is defined for EXIT (0). */ | |
204 | void | |
ccc6cda3 JA |
205 | initialize_terminating_signals () |
206 | { | |
207 | register int i; | |
d166f048 JA |
208 | #if defined (HAVE_POSIX_SIGNALS) |
209 | struct sigaction act, oact; | |
210 | #endif | |
211 | ||
212 | if (termsigs_initialized) | |
213 | return; | |
ccc6cda3 JA |
214 | |
215 | /* The following code is to avoid an expensive call to | |
216 | set_signal_handler () for each terminating_signals. Fortunately, | |
217 | this is possible in Posix. Unfortunately, we have to call signal () | |
218 | on non-Posix systems for each signal in terminating_signals. */ | |
219 | #if defined (HAVE_POSIX_SIGNALS) | |
ccc6cda3 JA |
220 | act.sa_handler = termination_unwind_protect; |
221 | act.sa_flags = 0; | |
222 | sigemptyset (&act.sa_mask); | |
223 | sigemptyset (&oact.sa_mask); | |
224 | for (i = 0; i < TERMSIGS_LENGTH; i++) | |
225 | sigaddset (&act.sa_mask, XSIG (i)); | |
226 | for (i = 0; i < TERMSIGS_LENGTH; i++) | |
227 | { | |
228 | sigaction (XSIG (i), &act, &oact); | |
d166f048 | 229 | XHANDLER(i) = oact.sa_handler; |
ccc6cda3 JA |
230 | /* Don't do anything with signals that are ignored at shell entry |
231 | if the shell is not interactive. */ | |
d166f048 | 232 | if (!interactive_shell && XHANDLER (i) == SIG_IGN) |
ccc6cda3 JA |
233 | { |
234 | sigaction (XSIG (i), &oact, &act); | |
235 | set_signal_ignored (XSIG (i)); | |
236 | } | |
cce855bc | 237 | #if defined (SIGPROF) && !defined (_MINIX) |
d166f048 JA |
238 | if (XSIG (i) == SIGPROF && XHANDLER (i) != SIG_DFL && XHANDLER (i) != SIG_IGN) |
239 | sigaction (XSIG (i), &oact, (struct sigaction *)NULL); | |
cce855bc | 240 | #endif /* SIGPROF && !_MINIX */ |
ccc6cda3 JA |
241 | } |
242 | ||
243 | #else /* !HAVE_POSIX_SIGNALS */ | |
244 | ||
245 | for (i = 0; i < TERMSIGS_LENGTH; i++) | |
246 | { | |
d166f048 | 247 | XHANDLER(i) = signal (XSIG (i), termination_unwind_protect); |
ccc6cda3 JA |
248 | /* Don't do anything with signals that are ignored at shell entry |
249 | if the shell is not interactive. */ | |
d166f048 | 250 | if (!interactive_shell && XHANDLER (i) == SIG_IGN) |
ccc6cda3 JA |
251 | { |
252 | signal (XSIG (i), SIG_IGN); | |
253 | set_signal_ignored (XSIG (i)); | |
254 | } | |
cce855bc | 255 | #ifdef SIGPROF |
d166f048 JA |
256 | if (XSIG (i) == SIGPROF && XHANDLER (i) != SIG_DFL && XHANDLER (i) != SIG_IGN) |
257 | signal (XSIG (i), XHANDLER (i)); | |
cce855bc | 258 | #endif |
ccc6cda3 JA |
259 | } |
260 | ||
261 | #endif /* !HAVE_POSIX_SIGNALS */ | |
262 | ||
d166f048 JA |
263 | termsigs_initialized = 1; |
264 | } | |
265 | ||
266 | static void | |
267 | initialize_shell_signals () | |
268 | { | |
269 | if (interactive) | |
270 | initialize_terminating_signals (); | |
271 | ||
ccc6cda3 JA |
272 | #if defined (JOB_CONTROL) || defined (HAVE_POSIX_SIGNALS) |
273 | /* All shells use the signal mask they inherit, and pass it along | |
274 | to child processes. Children will never block SIGCHLD, though. */ | |
275 | sigemptyset (&top_level_mask); | |
276 | sigprocmask (SIG_BLOCK, (sigset_t *)NULL, &top_level_mask); | |
bb70624e | 277 | # if defined (SIGCHLD) |
ccc6cda3 | 278 | sigdelset (&top_level_mask, SIGCHLD); |
bb70624e | 279 | # endif |
ccc6cda3 JA |
280 | #endif /* JOB_CONTROL || HAVE_POSIX_SIGNALS */ |
281 | ||
282 | /* And, some signals that are specifically ignored by the shell. */ | |
283 | set_signal_handler (SIGQUIT, SIG_IGN); | |
284 | ||
285 | if (interactive) | |
286 | { | |
287 | set_signal_handler (SIGINT, sigint_sighandler); | |
288 | set_signal_handler (SIGTERM, SIG_IGN); | |
289 | } | |
290 | } | |
291 | ||
292 | void | |
293 | reset_terminating_signals () | |
294 | { | |
295 | register int i; | |
ccc6cda3 JA |
296 | #if defined (HAVE_POSIX_SIGNALS) |
297 | struct sigaction act; | |
d166f048 | 298 | #endif |
ccc6cda3 | 299 | |
d166f048 JA |
300 | if (termsigs_initialized == 0) |
301 | return; | |
302 | ||
303 | #if defined (HAVE_POSIX_SIGNALS) | |
ccc6cda3 JA |
304 | act.sa_flags = 0; |
305 | sigemptyset (&act.sa_mask); | |
306 | for (i = 0; i < TERMSIGS_LENGTH; i++) | |
307 | { | |
308 | /* Skip a signal if it's trapped or handled specially, because the | |
309 | trap code will restore the correct value. */ | |
310 | if (signal_is_trapped (XSIG (i)) || signal_is_special (XSIG (i))) | |
311 | continue; | |
312 | ||
313 | act.sa_handler = XHANDLER (i); | |
314 | sigaction (XSIG (i), &act, (struct sigaction *) NULL); | |
315 | } | |
316 | #else /* !HAVE_POSIX_SIGNALS */ | |
317 | for (i = 0; i < TERMSIGS_LENGTH; i++) | |
318 | { | |
319 | if (signal_is_trapped (XSIG (i)) || signal_is_special (XSIG (i))) | |
320 | continue; | |
321 | ||
322 | signal (XSIG (i), XHANDLER (i)); | |
323 | } | |
324 | #endif /* !HAVE_POSIX_SIGNALS */ | |
325 | } | |
326 | #undef XSIG | |
327 | #undef XHANDLER | |
328 | ||
329 | /* What to do when we've been interrupted, and it is safe to handle it. */ | |
330 | void | |
331 | throw_to_top_level () | |
332 | { | |
333 | int print_newline = 0; | |
334 | ||
335 | if (interrupt_state) | |
336 | { | |
337 | print_newline = 1; | |
338 | DELINTERRUPT; | |
339 | } | |
340 | ||
341 | if (interrupt_state) | |
342 | return; | |
343 | ||
344 | last_command_exit_value |= 128; | |
345 | ||
346 | /* Run any traps set on SIGINT. */ | |
347 | run_interrupt_trap (); | |
348 | ||
349 | /* Cleanup string parser environment. */ | |
350 | while (parse_and_execute_level) | |
351 | parse_and_execute_cleanup (); | |
352 | ||
353 | #if defined (JOB_CONTROL) | |
354 | give_terminal_to (shell_pgrp); | |
355 | #endif /* JOB_CONTROL */ | |
356 | ||
357 | #if defined (JOB_CONTROL) || defined (HAVE_POSIX_SIGNALS) | |
358 | /* This should not be necessary on systems using sigsetjmp/siglongjmp. */ | |
359 | sigprocmask (SIG_SETMASK, &top_level_mask, (sigset_t *)NULL); | |
360 | #endif | |
361 | ||
362 | reset_parser (); | |
363 | ||
364 | #if defined (READLINE) | |
365 | if (interactive) | |
366 | bashline_reinitialize (); | |
367 | #endif /* READLINE */ | |
368 | ||
369 | #if defined (PROCESS_SUBSTITUTION) | |
370 | unlink_fifo_list (); | |
371 | #endif /* PROCESS_SUBSTITUTION */ | |
372 | ||
373 | run_unwind_protects (); | |
374 | loop_level = continuing = breaking = 0; | |
375 | return_catch_flag = 0; | |
376 | ||
377 | if (interactive && print_newline) | |
378 | { | |
379 | fflush (stdout); | |
380 | fprintf (stderr, "\n"); | |
381 | fflush (stderr); | |
382 | } | |
383 | ||
384 | /* An interrupted `wait' command in a script does not exit the script. */ | |
385 | if (interactive || (interactive_shell && !shell_initialized) || | |
386 | (print_newline && signal_is_trapped (SIGINT))) | |
387 | jump_to_top_level (DISCARD); | |
388 | else | |
389 | jump_to_top_level (EXITPROG); | |
390 | } | |
391 | ||
392 | /* This is just here to isolate the longjmp calls. */ | |
393 | void | |
394 | jump_to_top_level (value) | |
395 | int value; | |
396 | { | |
397 | longjmp (top_level, value); | |
398 | } | |
399 | ||
400 | sighandler | |
401 | termination_unwind_protect (sig) | |
402 | int sig; | |
403 | { | |
404 | if (sig == SIGINT && signal_is_trapped (SIGINT)) | |
405 | run_interrupt_trap (); | |
406 | ||
407 | #if defined (HISTORY) | |
408 | if (interactive_shell && sig != SIGABRT) | |
409 | maybe_save_shell_history (); | |
410 | #endif /* HISTORY */ | |
411 | ||
412 | #if defined (JOB_CONTROL) | |
413 | if (interactive && sig == SIGHUP) | |
414 | hangup_all_jobs (); | |
415 | end_job_control (); | |
416 | #endif /* JOB_CONTROL */ | |
417 | ||
418 | #if defined (PROCESS_SUBSTITUTION) | |
419 | unlink_fifo_list (); | |
420 | #endif /* PROCESS_SUBSTITUTION */ | |
421 | ||
422 | run_exit_trap (); | |
423 | set_signal_handler (sig, SIG_DFL); | |
424 | kill (getpid (), sig); | |
425 | ||
426 | SIGRETURN (0); | |
427 | } | |
428 | ||
429 | /* What we really do when SIGINT occurs. */ | |
430 | sighandler | |
431 | sigint_sighandler (sig) | |
432 | int sig; | |
433 | { | |
434 | #if defined (MUST_REINSTALL_SIGHANDLERS) | |
435 | signal (sig, sigint_sighandler); | |
436 | #endif | |
437 | ||
438 | /* interrupt_state needs to be set for the stack of interrupts to work | |
439 | right. Should it be set unconditionally? */ | |
440 | if (interrupt_state == 0) | |
441 | ADDINTERRUPT; | |
442 | ||
443 | if (interrupt_immediately) | |
444 | { | |
445 | interrupt_immediately = 0; | |
446 | throw_to_top_level (); | |
447 | } | |
448 | ||
449 | SIGRETURN (0); | |
450 | } | |
451 | ||
452 | /* Signal functions used by the rest of the code. */ | |
453 | #if !defined (HAVE_POSIX_SIGNALS) | |
454 | ||
455 | #if defined (JOB_CONTROL) | |
456 | /* Perform OPERATION on NEWSET, perhaps leaving information in OLDSET. */ | |
457 | sigprocmask (operation, newset, oldset) | |
458 | int operation, *newset, *oldset; | |
459 | { | |
460 | int old, new; | |
461 | ||
462 | if (newset) | |
463 | new = *newset; | |
464 | else | |
465 | new = 0; | |
466 | ||
467 | switch (operation) | |
468 | { | |
469 | case SIG_BLOCK: | |
470 | old = sigblock (new); | |
471 | break; | |
472 | ||
473 | case SIG_SETMASK: | |
474 | sigsetmask (new); | |
475 | break; | |
476 | ||
477 | default: | |
478 | internal_error ("Bad code in sig.c: sigprocmask"); | |
479 | } | |
480 | ||
481 | if (oldset) | |
482 | *oldset = old; | |
483 | } | |
484 | #endif /* JOB_CONTROL */ | |
485 | ||
486 | #else | |
487 | ||
488 | #if !defined (SA_INTERRUPT) | |
489 | # define SA_INTERRUPT 0 | |
490 | #endif | |
491 | ||
492 | #if !defined (SA_RESTART) | |
493 | # define SA_RESTART 0 | |
494 | #endif | |
495 | ||
496 | SigHandler * | |
497 | set_signal_handler (sig, handler) | |
498 | int sig; | |
499 | SigHandler *handler; | |
500 | { | |
501 | struct sigaction act, oact; | |
502 | ||
503 | act.sa_handler = handler; | |
504 | act.sa_flags = 0; | |
505 | #if 0 | |
506 | if (sig == SIGALRM) | |
507 | act.sa_flags |= SA_INTERRUPT; /* XXX */ | |
508 | else | |
509 | act.sa_flags |= SA_RESTART; /* XXX */ | |
510 | #endif | |
511 | sigemptyset (&act.sa_mask); | |
512 | sigemptyset (&oact.sa_mask); | |
513 | sigaction (sig, &act, &oact); | |
514 | return (oact.sa_handler); | |
515 | } | |
516 | #endif /* HAVE_POSIX_SIGNALS */ |