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 35extern "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 46namespace signals = utils::signals; 47 48 49/// Number of the last valid signal. 50const 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. 59void 60signals::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. 78bool 79signals::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