1 // Copyright 2010 The Kyua Authors.
2 // All rights reserved.
3 //
4 // Redistribution and use in source and binary forms, with or without
5 // modification, are permitted provided that the following conditions are
6 // met:
7 //
8 // * Redistributions of source code must retain the above copyright
9 // notice, this list of conditions and the following disclaimer.
10 // * Redistributions in binary form must reproduce the above copyright
11 // notice, this list of conditions and the following disclaimer in the
12 // documentation and/or other materials provided with the distribution.
13 // * Neither the name of Google Inc. nor the names of its contributors
14 // may be used to endorse or promote products derived from this software
15 // without specific prior written permission.
16 //
17 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28
29 #include "utils/signals/misc.hpp"
30
31 #if defined(HAVE_CONFIG_H)
32 # include "config.h"
33 #endif
34
35 extern "C" {
36 #include <signal.h>
37 }
38
39 #include <cerrno>
40 #include <cstddef>
41
42 #include "utils/format/macros.hpp"
43 #include "utils/logging/macros.hpp"
44 #include "utils/signals/exceptions.hpp"
45
46 namespace signals = utils::signals;
47
48
49 /// Number of the last valid signal.
50 const int utils::signals::last_signo = LAST_SIGNO;
51
52
53 /// Resets a signal handler to its default behavior.
54 ///
55 /// \param signo The number of the signal handler to reset.
56 ///
57 /// \throw signals::system_error If there is a problem trying to reset the
58 /// signal handler to its default behavior.
59 void
reset(const int signo)60 signals::reset(const int signo)
61 {
62 struct ::sigaction sa;
63 sa.sa_handler = SIG_DFL;
64 sigemptyset(&sa.sa_mask);
65 sa.sa_flags = 0;
66
67 if (::sigaction(signo, &sa, NULL) == -1) {
68 const int original_errno = errno;
69 throw system_error(F("Failed to reset signal %s") % signo,
70 original_errno);
71 }
72 }
73
74
75 /// Resets all signals to their default handlers.
76 ///
77 /// \return True if all signals could be reset properly; false otherwise.
78 bool
reset_all(void)79 signals::reset_all(void)
80 {
81 bool ok = true;
82
83 for (int signo = 1; signo <= signals::last_signo; ++signo) {
84 if (signo == SIGKILL || signo == SIGSTOP) {
85 // Don't attempt to reset immutable signals.
86 } else {
87 try {
88 signals::reset(signo);
89 } catch (const signals::error& e) {
90 #if defined(SIGTHR)
91 if (signo == SIGTHR) {
92 // If FreeBSD's libthr is loaded, it prevents us from
93 // modifying SIGTHR (at least in 11.0-CURRENT as of
94 // 2015-01-28). Skip failures for this signal if they
95 // happen to avoid this corner case.
96 continue;
97 }
98 #endif
99 LW(e.what());
100 ok = false;
101 }
102 }
103 }
104
105 return ok;
106 }
107