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42a4f53d | 1 | /* Copyright (C) 2016-2019 Free Software Foundation, Inc. |
f348d89a PA |
2 | |
3 | This file is part of GDB. | |
4 | ||
5 | This program is free software; you can redistribute it and/or modify | |
6 | it under the terms of the GNU General Public License as published by | |
7 | the Free Software Foundation; either version 3 of the License, or | |
8 | (at your option) any later version. | |
9 | ||
10 | This program is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
13 | GNU General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public License | |
16 | along with this program. If not, see <http://www.gnu.org/licenses/>. */ | |
17 | ||
18 | #include "common-defs.h" | |
19 | #include "signals-state-save-restore.h" | |
20 | ||
21 | #include <signal.h> | |
22 | ||
23 | /* The original signal actions and mask. */ | |
24 | ||
25 | #ifdef HAVE_SIGACTION | |
26 | static struct sigaction original_signal_actions[NSIG]; | |
27 | ||
28 | /* Note that we use sigprocmask without worrying about threads because | |
29 | the save/restore functions are called either from main, or after a | |
30 | fork. In both cases, we know the calling process is single | |
31 | threaded. */ | |
32 | static sigset_t original_signal_mask; | |
33 | #endif | |
34 | ||
35 | /* See signals-state-save-restore.h. */ | |
36 | ||
37 | void | |
e379cee6 | 38 | save_original_signals_state (bool quiet) |
f348d89a PA |
39 | { |
40 | #ifdef HAVE_SIGACTION | |
41 | int i; | |
42 | int res; | |
43 | ||
44 | res = sigprocmask (0, NULL, &original_signal_mask); | |
45 | if (res == -1) | |
669f9429 | 46 | perror_with_name (("sigprocmask")); |
f348d89a | 47 | |
e379cee6 PA |
48 | bool found_preinstalled = false; |
49 | ||
f348d89a PA |
50 | for (i = 1; i < NSIG; i++) |
51 | { | |
52 | struct sigaction *oldact = &original_signal_actions[i]; | |
53 | ||
54 | res = sigaction (i, NULL, oldact); | |
55 | if (res == -1 && errno == EINVAL) | |
56 | { | |
57 | /* Some signal numbers in the range are invalid. */ | |
58 | continue; | |
59 | } | |
60 | else if (res == -1) | |
669f9429 | 61 | perror_with_name (("sigaction")); |
f348d89a PA |
62 | |
63 | /* If we find a custom signal handler already installed, then | |
e379cee6 PA |
64 | this function was called too late. This is a warning instead |
65 | of an internal error because this can also happen if you | |
66 | LD_PRELOAD a library that installs a signal handler early via | |
67 | __attribute__((constructor)), like libSegFault.so. */ | |
68 | if (!quiet | |
69 | && oldact->sa_handler != SIG_DFL | |
70 | && oldact->sa_handler != SIG_IGN) | |
71 | { | |
72 | found_preinstalled = true; | |
73 | ||
74 | /* Use raw fprintf here because we're being called in early | |
db422fb2 | 75 | startup, before GDB's filtered streams are created. */ |
e379cee6 PA |
76 | fprintf (stderr, |
77 | _("warning: Found custom handler for signal " | |
78 | "%d (%s) preinstalled.\n"), i, | |
79 | strsignal (i)); | |
80 | } | |
81 | } | |
82 | ||
83 | if (found_preinstalled) | |
84 | { | |
85 | fprintf (stderr, _("\ | |
86 | Some signal dispositions inherited from the environment (SIG_DFL/SIG_IGN)\n\ | |
87 | won't be propagated to spawned programs.\n")); | |
f348d89a PA |
88 | } |
89 | #endif | |
90 | } | |
91 | ||
92 | /* See signals-state-save-restore.h. */ | |
93 | ||
94 | void | |
95 | restore_original_signals_state (void) | |
96 | { | |
97 | #ifdef HAVE_SIGACTION | |
98 | int i; | |
99 | int res; | |
100 | ||
101 | for (i = 1; i < NSIG; i++) | |
102 | { | |
103 | res = sigaction (i, &original_signal_actions[i], NULL); | |
104 | if (res == -1 && errno == EINVAL) | |
105 | { | |
106 | /* Some signal numbers in the range are invalid. */ | |
107 | continue; | |
108 | } | |
109 | else if (res == -1) | |
669f9429 | 110 | perror_with_name (("sigaction")); |
f348d89a PA |
111 | } |
112 | ||
113 | res = sigprocmask (SIG_SETMASK, &original_signal_mask, NULL); | |
114 | if (res == -1) | |
669f9429 | 115 | perror_with_name (("sigprocmask")); |
f348d89a PA |
116 | #endif |
117 | } |