-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathtrap.c
1582 lines (1364 loc) · 43 KB
/
trap.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* trap.c -- Not the trap command, but useful functions for manipulating
those objects. The trap command is in builtins/trap.def. */
/* Copyright (C) 1987-2021 Free Software Foundation, Inc.
This file is part of GNU Bash, the Bourne Again SHell.
Bash is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Bash is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Bash. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#if defined (HAVE_UNISTD_H)
# include <unistd.h>
#endif
#include "bashtypes.h"
#include "bashansi.h"
#include <stdio.h>
#include <errno.h>
#include "bashintl.h"
#include <signal.h>
#include "trap.h"
#include "shell.h"
#include "execute_cmd.h"
#include "flags.h"
#include "parser.h"
#include "input.h" /* for save_token_state, restore_token_state */
#include "jobs.h"
#include "signames.h"
#include "builtins.h"
#include "builtins/common.h"
#include "builtins/builtext.h"
#if defined (READLINE)
# include <readline/readline.h>
# include "bashline.h"
#endif
#ifndef errno
extern int errno;
#endif
/* Flags which describe the current handling state of a signal. */
#define SIG_INHERITED 0x0 /* Value inherited from parent. */
#define SIG_TRAPPED 0x1 /* Currently trapped. */
#define SIG_HARD_IGNORE 0x2 /* Signal was ignored on shell entry. */
#define SIG_SPECIAL 0x4 /* Treat this signal specially. */
#define SIG_NO_TRAP 0x8 /* Signal cannot be trapped. */
#define SIG_INPROGRESS 0x10 /* Signal handler currently executing. */
#define SIG_CHANGED 0x20 /* Trap value changed in trap handler. */
#define SIG_IGNORED 0x40 /* The signal is currently being ignored. */
#define SPECIAL_TRAP(s) ((s) == EXIT_TRAP || (s) == DEBUG_TRAP || (s) == ERROR_TRAP || (s) == RETURN_TRAP)
/* An array of such flags, one for each signal, describing what the
shell will do with a signal. DEBUG_TRAP == NSIG; some code below
assumes this. */
static int sigmodes[BASH_NSIG];
static void free_trap_command (int);
static void change_signal (int, char *);
static int _run_trap_internal (int, char *);
static void free_trap_string (int);
static void reset_signal (int);
static void restore_signal (int);
static void reset_or_restore_signal_handlers (sh_resetsig_func_t *);
static void reinit_trap (int);
static void trap_if_untrapped (int, char *);
/* Variables used here but defined in other files. */
extern volatile int from_return_trap;
extern int waiting_for_child;
extern WORD_LIST *subst_assign_varlist;
/* The list of things to do originally, before we started trapping. */
SigHandler *original_signals[NSIG];
/* For each signal, a slot for a string, which is a command to be
executed when that signal is received. The slot can also contain
DEFAULT_SIG, which means do whatever you were going to do before
you were so rudely interrupted, or IGNORE_SIG, which says ignore
this signal. */
char *trap_list[BASH_NSIG];
/* A bitmap of signals received for which we have trap handlers. */
int pending_traps[NSIG];
/* Set to the number of the signal we're running the trap for + 1.
Used in execute_cmd.c and builtins/common.c to clean up when
parse_and_execute does not return normally after executing the
trap command (e.g., when `return' is executed in the trap command). */
int running_trap;
/* Set to last_command_exit_value before running a trap. */
int trap_saved_exit_value;
/* The (trapped) signal received while executing in the `wait' builtin */
int wait_signal_received;
int trapped_signal_received;
/* Set to 1 to suppress the effect of `set v' in the DEBUG trap. */
int suppress_debug_trap_verbose = 0;
#define GETORIGSIG(sig) \
do { \
original_signals[sig] = (SigHandler *)set_signal_handler (sig, SIG_DFL); \
set_signal_handler (sig, original_signals[sig]); \
if (original_signals[sig] == SIG_IGN) \
sigmodes[sig] |= SIG_HARD_IGNORE; \
} while (0)
#define SETORIGSIG(sig,handler) \
do { \
original_signals[sig] = handler; \
if (original_signals[sig] == SIG_IGN) \
sigmodes[sig] |= SIG_HARD_IGNORE; \
} while (0)
#define GET_ORIGINAL_SIGNAL(sig) \
if (sig && sig < NSIG && original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER) \
GETORIGSIG(sig)
void
initialize_traps ()
{
register int i;
initialize_signames();
trap_list[EXIT_TRAP] = trap_list[DEBUG_TRAP] = trap_list[ERROR_TRAP] = trap_list[RETURN_TRAP] = (char *)NULL;
sigmodes[EXIT_TRAP] = sigmodes[DEBUG_TRAP] = sigmodes[ERROR_TRAP] = sigmodes[RETURN_TRAP] = SIG_INHERITED;
original_signals[EXIT_TRAP] = IMPOSSIBLE_TRAP_HANDLER;
for (i = 1; i < NSIG; i++)
{
pending_traps[i] = 0;
trap_list[i] = (char *)DEFAULT_SIG;
sigmodes[i] = SIG_INHERITED; /* XXX - only set, not used */
original_signals[i] = IMPOSSIBLE_TRAP_HANDLER;
}
/* Show which signals are treated specially by the shell. */
#if defined (SIGCHLD)
GETORIGSIG (SIGCHLD);
sigmodes[SIGCHLD] |= (SIG_SPECIAL | SIG_NO_TRAP);
#endif /* SIGCHLD */
GETORIGSIG (SIGINT);
sigmodes[SIGINT] |= SIG_SPECIAL;
#if defined (__BEOS__)
/* BeOS sets SIGINT to SIG_IGN! */
original_signals[SIGINT] = SIG_DFL;
sigmodes[SIGINT] &= ~SIG_HARD_IGNORE;
#endif
GETORIGSIG (SIGQUIT);
sigmodes[SIGQUIT] |= SIG_SPECIAL;
if (interactive)
{
GETORIGSIG (SIGTERM);
sigmodes[SIGTERM] |= SIG_SPECIAL;
}
get_original_tty_job_signals ();
}
#ifdef DEBUG
/* Return a printable representation of the trap handler for SIG. */
static char *
trap_handler_string (sig)
int sig;
{
if (trap_list[sig] == (char *)DEFAULT_SIG)
return "DEFAULT_SIG";
else if (trap_list[sig] == (char *)IGNORE_SIG)
return "IGNORE_SIG";
else if (trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER)
return "IMPOSSIBLE_TRAP_HANDLER";
else if (trap_list[sig])
return trap_list[sig];
else
return "NULL";
}
#endif
/* Return the print name of this signal. */
char *
signal_name (sig)
int sig;
{
char *ret;
/* on cygwin32, signal_names[sig] could be null */
ret = (sig >= BASH_NSIG || sig < 0 || signal_names[sig] == NULL)
? _("invalid signal number")
: signal_names[sig];
return ret;
}
/* Turn a string into a signal number, or a number into
a signal number. If STRING is "2", "SIGINT", or "INT",
then (int)2 is returned. Return NO_SIG if STRING doesn't
contain a valid signal descriptor. */
int
decode_signal (string, flags)
char *string;
int flags;
{
intmax_t sig;
char *name;
if (legal_number (string, &sig))
return ((sig >= 0 && sig < NSIG) ? (int)sig : NO_SIG);
#if defined (SIGRTMIN) && defined (SIGRTMAX)
if (STREQN (string, "SIGRTMIN+", 9) || ((flags & DSIG_NOCASE) && strncasecmp (string, "SIGRTMIN+", 9) == 0))
{
if (legal_number (string+9, &sig) && sig >= 0 && sig <= SIGRTMAX - SIGRTMIN)
return (SIGRTMIN + sig);
else
return NO_SIG;
}
else if (STREQN (string, "RTMIN+", 6) || ((flags & DSIG_NOCASE) && strncasecmp (string, "RTMIN+", 6) == 0))
{
if (legal_number (string+6, &sig) && sig >= 0 && sig <= SIGRTMAX - SIGRTMIN)
return (SIGRTMIN + sig);
else
return NO_SIG;
}
#endif /* SIGRTMIN && SIGRTMAX */
/* A leading `SIG' may be omitted. */
for (sig = 0; sig < BASH_NSIG; sig++)
{
name = signal_names[sig];
if (name == 0 || name[0] == '\0')
continue;
/* Check name without the SIG prefix first case sensitively or
insensitively depending on whether flags includes DSIG_NOCASE */
if (STREQN (name, "SIG", 3))
{
name += 3;
if ((flags & DSIG_NOCASE) && strcasecmp (string, name) == 0)
return ((int)sig);
else if ((flags & DSIG_NOCASE) == 0 && strcmp (string, name) == 0)
return ((int)sig);
/* If we can't use the `SIG' prefix to match, punt on this
name now. */
else if ((flags & DSIG_SIGPREFIX) == 0)
continue;
}
/* Check name with SIG prefix case sensitively or insensitively
depending on whether flags includes DSIG_NOCASE */
name = signal_names[sig];
if ((flags & DSIG_NOCASE) && strcasecmp (string, name) == 0)
return ((int)sig);
else if ((flags & DSIG_NOCASE) == 0 && strcmp (string, name) == 0)
return ((int)sig);
}
return (NO_SIG);
}
/* Non-zero when we catch a trapped signal. */
static int catch_flag;
void
run_pending_traps ()
{
register int sig;
int x;
volatile int old_exit_value, old_running;
WORD_LIST *save_subst_varlist;
HASH_TABLE *save_tempenv;
sh_parser_state_t pstate;
volatile int save_return_catch_flag, function_code;
procenv_t save_return_catch;
char *trap_command, *old_trap;
#if defined (ARRAY_VARS)
ARRAY *ps;
#endif
if (catch_flag == 0) /* simple optimization */
return;
if (running_trap > 0)
{
internal_debug ("run_pending_traps: recursive invocation while running trap for signal %d", running_trap-1);
#if defined (SIGWINCH)
if (running_trap == SIGWINCH+1 && pending_traps[SIGWINCH])
return; /* no recursive SIGWINCH trap invocations */
#endif
/* could check for running the trap handler for the same signal here
(running_trap == sig+1) */
if (evalnest_max > 0 && evalnest > evalnest_max)
{
internal_error (_("trap handler: maximum trap handler level exceeded (%d)"), evalnest_max);
evalnest = 0;
jump_to_top_level (DISCARD);
}
}
catch_flag = trapped_signal_received = 0;
/* Preserve $? when running trap. */
trap_saved_exit_value = old_exit_value = last_command_exit_value;
#if defined (ARRAY_VARS)
ps = save_pipestatus_array ();
#endif
old_running = running_trap;
for (sig = 1; sig < NSIG; sig++)
{
/* XXX this could be made into a counter by using
while (pending_traps[sig]--) instead of the if statement. */
if (pending_traps[sig])
{
/* XXX - set last_command_exit_value = trap_saved_exit_value here? */
running_trap = sig + 1;
if (sig == SIGINT)
{
pending_traps[sig] = 0; /* XXX */
/* We don't modify evalnest here, since run_interrupt_trap() calls
_run_trap_internal, which does. */
run_interrupt_trap (0);
CLRINTERRUPT; /* interrupts don't stack */
}
#if defined (JOB_CONTROL) && defined (SIGCHLD)
else if (sig == SIGCHLD &&
trap_list[SIGCHLD] != (char *)IMPOSSIBLE_TRAP_HANDLER &&
(sigmodes[SIGCHLD] & SIG_INPROGRESS) == 0)
{
sigmodes[SIGCHLD] |= SIG_INPROGRESS;
/* We modify evalnest here even though run_sigchld_trap can run
the trap action more than once */
evalnest++;
x = pending_traps[sig];
pending_traps[sig] = 0;
run_sigchld_trap (x); /* use as counter */
running_trap = 0;
evalnest--;
sigmodes[SIGCHLD] &= ~SIG_INPROGRESS;
/* continue here rather than reset pending_traps[SIGCHLD] below in
case there are recursive calls to run_pending_traps and children
have been reaped while run_sigchld_trap was running. */
continue;
}
else if (sig == SIGCHLD &&
trap_list[SIGCHLD] == (char *)IMPOSSIBLE_TRAP_HANDLER &&
(sigmodes[SIGCHLD] & SIG_INPROGRESS) != 0)
{
/* This can happen when run_pending_traps is called while
running a SIGCHLD trap handler. */
running_trap = 0;
/* want to leave pending_traps[SIGCHLD] alone here */
continue; /* XXX */
}
else if (sig == SIGCHLD && (sigmodes[SIGCHLD] & SIG_INPROGRESS))
{
/* whoops -- print warning? */
running_trap = 0; /* XXX */
/* want to leave pending_traps[SIGCHLD] alone here */
continue;
}
#endif
else if (trap_list[sig] == (char *)DEFAULT_SIG ||
trap_list[sig] == (char *)IGNORE_SIG ||
trap_list[sig] == (char *)IMPOSSIBLE_TRAP_HANDLER)
{
/* This is possible due to a race condition. Say a bash
process has SIGTERM trapped. A subshell is spawned
using { list; } & and the parent does something and kills
the subshell with SIGTERM. It's possible for the subshell
to set pending_traps[SIGTERM] to 1 before the code in
execute_cmd.c eventually calls restore_original_signals
to reset the SIGTERM signal handler in the subshell. The
next time run_pending_traps is called, pending_traps[SIGTERM]
will be 1, but the trap handler in trap_list[SIGTERM] will
be invalid (probably DEFAULT_SIG, but it could be IGNORE_SIG).
Unless we catch this, the subshell will dump core when
trap_list[SIGTERM] == DEFAULT_SIG, because DEFAULT_SIG is
usually 0x0. */
internal_warning (_("run_pending_traps: bad value in trap_list[%d]: %p"),
sig, trap_list[sig]);
if (trap_list[sig] == (char *)DEFAULT_SIG)
{
internal_warning (_("run_pending_traps: signal handler is SIG_DFL, resending %d (%s) to myself"), sig, signal_name (sig));
kill (getpid (), sig);
}
}
else
{
old_trap = trap_list[sig];
trap_command = savestring (old_trap);
save_parser_state (&pstate);
save_subst_varlist = subst_assign_varlist;
subst_assign_varlist = 0;
save_tempenv = temporary_env;
temporary_env = 0; /* traps should not run with temporary env */
#if defined (JOB_CONTROL)
save_pipeline (1); /* XXX only provides one save level */
#endif
/* XXX - set pending_traps[sig] = 0 here? */
pending_traps[sig] = 0;
evalnest++;
function_code = 0;
save_return_catch_flag = return_catch_flag;
if (return_catch_flag)
{
COPY_PROCENV (return_catch, save_return_catch);
function_code = setjmp_nosigs (return_catch);
}
if (function_code == 0)
/* XXX is x always last_command_exit_value? */
x = parse_and_execute (trap_command, "trap", SEVAL_NONINT|SEVAL_NOHIST|SEVAL_RESETLINE|SEVAL_NOOPTIMIZE);
else
{
parse_and_execute_cleanup (sig + 1); /* XXX - could use -1 */
x = return_catch_value;
}
evalnest--;
#if defined (JOB_CONTROL)
restore_pipeline (1);
#endif
subst_assign_varlist = save_subst_varlist;
restore_parser_state (&pstate);
temporary_env = save_tempenv;
if (save_return_catch_flag)
{
return_catch_flag = save_return_catch_flag;
return_catch_value = x;
COPY_PROCENV (save_return_catch, return_catch);
if (function_code)
{
running_trap = old_running; /* XXX */
/* caller will set last_command_exit_value */
sh_longjmp (return_catch, 1);
}
}
}
pending_traps[sig] = 0; /* XXX - move before evalstring? */
running_trap = old_running;
}
}
#if defined (ARRAY_VARS)
restore_pipestatus_array (ps);
#endif
last_command_exit_value = old_exit_value;
}
/* Set the private state variables noting that we received a signal SIG
for which we have a trap set. */
void
set_trap_state (sig)
int sig;
{
catch_flag = 1;
pending_traps[sig]++;
trapped_signal_received = sig;
}
sighandler
trap_handler (sig)
int sig;
{
int oerrno;
if ((sigmodes[sig] & SIG_TRAPPED) == 0)
{
internal_debug ("trap_handler: signal %d: signal not trapped", sig);
SIGRETURN (0);
}
/* This means we're in a subshell, but have not yet reset the handler for
trapped signals. We're not supposed to execute the trap in this situation;
we should restore the original signal and resend the signal to ourselves
to preserve the Posix "signal traps that are not being ignored shall be
set to the default action" semantics. */
if ((subshell_environment & SUBSHELL_IGNTRAP) && trap_list[sig] != (char *)IGNORE_SIG)
{
sigset_t mask;
/* Paranoia */
if (original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER)
original_signals[sig] = SIG_DFL;
restore_signal (sig);
/* Make sure we let the signal we just caught through */
sigemptyset (&mask);
sigprocmask (SIG_SETMASK, (sigset_t *)NULL, &mask);
sigdelset (&mask, sig);
sigprocmask (SIG_SETMASK, &mask, (sigset_t *)NULL);
kill (getpid (), sig);
SIGRETURN (0);
}
if ((sig >= NSIG) ||
(trap_list[sig] == (char *)DEFAULT_SIG) ||
(trap_list[sig] == (char *)IGNORE_SIG))
programming_error (_("trap_handler: bad signal %d"), sig);
else
{
oerrno = errno;
#if defined (MUST_REINSTALL_SIGHANDLERS)
# if defined (JOB_CONTROL) && defined (SIGCHLD)
if (sig != SIGCHLD)
# endif /* JOB_CONTROL && SIGCHLD */
set_signal_handler (sig, trap_handler);
#endif /* MUST_REINSTALL_SIGHANDLERS */
set_trap_state (sig);
if (this_shell_builtin && (this_shell_builtin == wait_builtin))
{
wait_signal_received = sig;
if (waiting_for_child && wait_intr_flag)
sh_longjmp (wait_intr_buf, 1);
}
#if defined (READLINE)
/* Set the event hook so readline will call it after the signal handlers
finish executing, so if this interrupted character input we can get
quick response. */
if (RL_ISSTATE (RL_STATE_SIGHANDLER))
bashline_set_event_hook ();
#endif
errno = oerrno;
}
SIGRETURN (0);
}
int
next_pending_trap (start)
int start;
{
register int i;
for (i = start; i < NSIG; i++)
if (pending_traps[i])
return i;
return -1;
}
int
first_pending_trap ()
{
return (next_pending_trap (1));
}
/* Return > 0 if any of the "real" signals (not fake signals like EXIT) are
trapped. */
int
any_signals_trapped ()
{
register int i;
for (i = 1; i < NSIG; i++)
if ((sigmodes[i] & SIG_TRAPPED) && (sigmodes[i] & SIG_IGNORED) == 0)
return i;
return -1;
}
void
clear_pending_traps ()
{
register int i;
for (i = 1; i < NSIG; i++)
pending_traps[i] = 0;
}
void
check_signals ()
{
/* Add any other shell timeouts here */
check_read_timeout (); /* set by the read builtin */
QUIT;
}
/* Convenience functions the rest of the shell can use */
void
check_signals_and_traps ()
{
check_signals ();
run_pending_traps ();
}
#if defined (JOB_CONTROL) && defined (SIGCHLD)
#ifdef INCLUDE_UNUSED
/* Make COMMAND_STRING be executed when SIGCHLD is caught. */
void
set_sigchld_trap (command_string)
char *command_string;
{
set_signal (SIGCHLD, command_string);
}
#endif
/* Make COMMAND_STRING be executed when SIGCHLD is caught iff SIGCHLD
is not already trapped. IMPOSSIBLE_TRAP_HANDLER is used as a sentinel
to make sure that a SIGCHLD trap handler run via run_sigchld_trap can
reset the disposition to the default and not have the original signal
accidentally restored, undoing the user's command. */
void
maybe_set_sigchld_trap (command_string)
char *command_string;
{
if ((sigmodes[SIGCHLD] & SIG_TRAPPED) == 0 && trap_list[SIGCHLD] == (char *)IMPOSSIBLE_TRAP_HANDLER)
set_signal (SIGCHLD, command_string);
}
/* Temporarily set the SIGCHLD trap string to IMPOSSIBLE_TRAP_HANDLER. Used
as a sentinel in run_sigchld_trap and maybe_set_sigchld_trap to see whether
or not a SIGCHLD trap handler reset SIGCHLD disposition to the default. */
void
set_impossible_sigchld_trap ()
{
restore_default_signal (SIGCHLD);
change_signal (SIGCHLD, (char *)IMPOSSIBLE_TRAP_HANDLER);
sigmodes[SIGCHLD] &= ~SIG_TRAPPED; /* maybe_set_sigchld_trap checks this */
}
/* Act as if we received SIGCHLD NCHILD times and increment
pending_traps[SIGCHLD] by that amount. This allows us to still run the
SIGCHLD trap once for each exited child. */
void
queue_sigchld_trap (nchild)
int nchild;
{
if (nchild > 0)
{
catch_flag = 1;
pending_traps[SIGCHLD] += nchild;
trapped_signal_received = SIGCHLD;
}
}
#endif /* JOB_CONTROL && SIGCHLD */
/* Set a trap for SIG only if SIG is not already trapped. */
static inline void
trap_if_untrapped (sig, command)
int sig;
char *command;
{
if ((sigmodes[sig] & SIG_TRAPPED) == 0)
set_signal (sig, command);
}
void
set_debug_trap (command)
char *command;
{
set_signal (DEBUG_TRAP, command);
}
/* Separate function to call when functions and sourced files want to restore
the original version of the DEBUG trap before returning. Unless the -T
option is set, source and shell function execution save the old debug trap
and unset the trap. If the function or sourced file changes the DEBUG trap,
SIG_TRAPPED will be set and we don't bother restoring the original trap string.
This is used by both functions and the source builtin. */
void
maybe_set_debug_trap (command)
char *command;
{
trap_if_untrapped (DEBUG_TRAP, command);
}
void
set_error_trap (command)
char *command;
{
set_signal (ERROR_TRAP, command);
}
void
maybe_set_error_trap (command)
char *command;
{
trap_if_untrapped (ERROR_TRAP, command);
}
void
set_return_trap (command)
char *command;
{
set_signal (RETURN_TRAP, command);
}
void
maybe_set_return_trap (command)
char *command;
{
trap_if_untrapped (RETURN_TRAP, command);
}
#ifdef INCLUDE_UNUSED
void
set_sigint_trap (command)
char *command;
{
set_signal (SIGINT, command);
}
#endif
/* Reset the SIGINT handler so that subshells that are doing `shellsy'
things, like waiting for command substitution or executing commands
in explicit subshells ( ( cmd ) ), can catch interrupts properly. */
SigHandler *
set_sigint_handler ()
{
if (sigmodes[SIGINT] & SIG_HARD_IGNORE)
return ((SigHandler *)SIG_IGN);
else if (sigmodes[SIGINT] & SIG_IGNORED)
return ((SigHandler *)set_signal_handler (SIGINT, SIG_IGN)); /* XXX */
else if (sigmodes[SIGINT] & SIG_TRAPPED)
return ((SigHandler *)set_signal_handler (SIGINT, trap_handler));
/* The signal is not trapped, so set the handler to the shell's special
interrupt handler. */
else if (interactive) /* XXX - was interactive_shell */
return (set_signal_handler (SIGINT, sigint_sighandler));
else
return (set_signal_handler (SIGINT, termsig_sighandler));
}
/* Return the correct handler for signal SIG according to the values in
sigmodes[SIG]. */
SigHandler *
trap_to_sighandler (sig)
int sig;
{
if (sigmodes[sig] & (SIG_IGNORED|SIG_HARD_IGNORE))
return (SIG_IGN);
else if (sigmodes[sig] & SIG_TRAPPED)
return (trap_handler);
else
return (SIG_DFL);
}
/* Set SIG to call STRING as a command. */
void
set_signal (sig, string)
int sig;
char *string;
{
sigset_t set, oset;
if (SPECIAL_TRAP (sig))
{
change_signal (sig, savestring (string));
if (sig == EXIT_TRAP && interactive == 0)
initialize_terminating_signals ();
return;
}
/* A signal ignored on entry to the shell cannot be trapped or reset, but
no error is reported when attempting to do so. -- Posix.2 */
if (sigmodes[sig] & SIG_HARD_IGNORE)
return;
/* Make sure we have original_signals[sig] if the signal has not yet
been trapped. */
if ((sigmodes[sig] & SIG_TRAPPED) == 0)
{
/* If we aren't sure of the original value, check it. */
if (original_signals[sig] == IMPOSSIBLE_TRAP_HANDLER)
GETORIGSIG (sig);
if (original_signals[sig] == SIG_IGN)
return;
}
/* Only change the system signal handler if SIG_NO_TRAP is not set.
The trap command string is changed in either case. The shell signal
handlers for SIGINT and SIGCHLD run the user specified traps in an
environment in which it is safe to do so. */
if ((sigmodes[sig] & SIG_NO_TRAP) == 0)
{
BLOCK_SIGNAL (sig, set, oset);
change_signal (sig, savestring (string));
set_signal_handler (sig, trap_handler);
UNBLOCK_SIGNAL (oset);
}
else
change_signal (sig, savestring (string));
}
static void
free_trap_command (sig)
int sig;
{
if ((sigmodes[sig] & SIG_TRAPPED) && trap_list[sig] &&
(trap_list[sig] != (char *)IGNORE_SIG) &&
(trap_list[sig] != (char *)DEFAULT_SIG) &&
(trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER))
free (trap_list[sig]);
}
/* If SIG has a string assigned to it, get rid of it. Then give it
VALUE. */
static void
change_signal (sig, value)
int sig;
char *value;
{
if ((sigmodes[sig] & SIG_INPROGRESS) == 0)
free_trap_command (sig);
trap_list[sig] = value;
sigmodes[sig] |= SIG_TRAPPED;
if (value == (char *)IGNORE_SIG)
sigmodes[sig] |= SIG_IGNORED;
else
sigmodes[sig] &= ~SIG_IGNORED;
if (sigmodes[sig] & SIG_INPROGRESS)
sigmodes[sig] |= SIG_CHANGED;
}
void
get_original_signal (sig)
int sig;
{
/* If we aren't sure the of the original value, then get it. */
if (sig > 0 && sig < NSIG && original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER)
GETORIGSIG (sig);
}
void
get_all_original_signals ()
{
register int i;
for (i = 1; i < NSIG; i++)
GET_ORIGINAL_SIGNAL (i);
}
void
set_original_signal (sig, handler)
int sig;
SigHandler *handler;
{
if (sig > 0 && sig < NSIG && original_signals[sig] == (SigHandler *)IMPOSSIBLE_TRAP_HANDLER)
SETORIGSIG (sig, handler);
}
/* Restore the default action for SIG; i.e., the action the shell
would have taken before you used the trap command. This is called
from trap_builtin (), which takes care to restore the handlers for
the signals the shell treats specially. */
void
restore_default_signal (sig)
int sig;
{
if (SPECIAL_TRAP (sig))
{
if ((sig != DEBUG_TRAP && sig != ERROR_TRAP && sig != RETURN_TRAP) ||
(sigmodes[sig] & SIG_INPROGRESS) == 0)
free_trap_command (sig);
trap_list[sig] = (char *)NULL;
sigmodes[sig] &= ~SIG_TRAPPED;
if (sigmodes[sig] & SIG_INPROGRESS)
sigmodes[sig] |= SIG_CHANGED;
return;
}
GET_ORIGINAL_SIGNAL (sig);
/* A signal ignored on entry to the shell cannot be trapped or reset, but
no error is reported when attempting to do so. Thanks Posix.2. */
if (sigmodes[sig] & SIG_HARD_IGNORE)
return;
/* If we aren't trapping this signal, don't bother doing anything else. */
/* We special-case SIGCHLD and IMPOSSIBLE_TRAP_HANDLER (see above) as a
sentinel to determine whether or not disposition is reset to the default
while the trap handler is executing. */
if (((sigmodes[sig] & SIG_TRAPPED) == 0) &&
(sig != SIGCHLD || (sigmodes[sig] & SIG_INPROGRESS) == 0 || trap_list[sig] != (char *)IMPOSSIBLE_TRAP_HANDLER))
return;
/* Only change the signal handler for SIG if it allows it. */
if ((sigmodes[sig] & SIG_NO_TRAP) == 0)
set_signal_handler (sig, original_signals[sig]);
/* Change the trap command in either case. */
change_signal (sig, (char *)DEFAULT_SIG);
/* Mark the signal as no longer trapped. */
sigmodes[sig] &= ~SIG_TRAPPED;
}
/* Make this signal be ignored. */
void
ignore_signal (sig)
int sig;
{
if (SPECIAL_TRAP (sig) && ((sigmodes[sig] & SIG_IGNORED) == 0))
{
change_signal (sig, (char *)IGNORE_SIG);
return;
}
GET_ORIGINAL_SIGNAL (sig);
/* A signal ignored on entry to the shell cannot be trapped or reset.
No error is reported when the user attempts to do so. */
if (sigmodes[sig] & SIG_HARD_IGNORE)
return;
/* If already trapped and ignored, no change necessary. */
if (sigmodes[sig] & SIG_IGNORED)
return;
/* Only change the signal handler for SIG if it allows it. */
if ((sigmodes[sig] & SIG_NO_TRAP) == 0)
set_signal_handler (sig, SIG_IGN);
/* Change the trap command in either case. */
change_signal (sig, (char *)IGNORE_SIG);
}
/* Handle the calling of "trap 0". The only sticky situation is when
the command to be executed includes an "exit". This is why we have
to provide our own place for top_level to jump to. */
int
run_exit_trap ()
{
char *trap_command;
int code, function_code, retval;
#if defined (ARRAY_VARS)
ARRAY *ps;
#endif
trap_saved_exit_value = last_command_exit_value;
#if defined (ARRAY_VARS)
ps = save_pipestatus_array ();
#endif
function_code = 0;
/* Run the trap only if signal 0 is trapped and not ignored, and we are not
currently running in the trap handler (call to exit in the list of
commands given to trap 0). */
if ((sigmodes[EXIT_TRAP] & SIG_TRAPPED) &&
(sigmodes[EXIT_TRAP] & (SIG_IGNORED|SIG_INPROGRESS)) == 0)
{
trap_command = savestring (trap_list[EXIT_TRAP]);
sigmodes[EXIT_TRAP] &= ~SIG_TRAPPED;
sigmodes[EXIT_TRAP] |= SIG_INPROGRESS;
retval = trap_saved_exit_value;
running_trap = 1;