1 /*** 2 This file is part of libdaemon. 3 4 Copyright 2003-2008 Lennart Poettering 5 6 Permission is hereby granted, free of charge, to any person obtaining a copy 7 of this software and associated documentation files (the "Software"), to deal 8 in the Software without restriction, including without limitation the rights 9 to use, copy, modify, merge, publish, distribute, sublicense, and/or sell 10 copies of the Software, and to permit persons to whom the Software is 11 furnished to do so, subject to the following conditions: 12 13 The above copyright notice and this permission notice shall be included in 14 all copies or substantial portions of the Software. 15 16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE 19 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 22 SOFTWARE. 23 24 ***/ 25 26 #ifdef HAVE_CONFIG_H 27 #include <config.h> 28 #endif 29 30 #include <fcntl.h> 31 #include <unistd.h> 32 #include <errno.h> 33 #include <string.h> 34 #include <stdarg.h> 35 #include <signal.h> 36 37 #include "dsignal.h" 38 #include "dlog.h" 39 #include "dnonblock.h" 40 41 static int _signal_pipe[2] = { -1, -1 }; 42 43 static void _sigfunc(int s) { 44 int saved_errno = errno; 45 write(_signal_pipe[1], &s, sizeof(s)); 46 errno = saved_errno; 47 } 48 49 static int _init(void) { 50 51 if (_signal_pipe[0] < 0 || _signal_pipe[1] < 0) { 52 if (pipe(_signal_pipe) < 0) { 53 daemon_log(LOG_ERR, "pipe(): %s", strerror(errno)); 54 return -1; 55 } 56 57 if (daemon_nonblock(_signal_pipe[0], 1) < 0 || daemon_nonblock(_signal_pipe[1], 1) < 0) { 58 daemon_signal_done(); 59 return -1; 60 } 61 } 62 63 return 0; 64 } 65 66 int daemon_signal_install(int s){ 67 sigset_t ss; 68 struct sigaction sa; 69 70 if (_init() < 0) 71 return -1; 72 73 if (sigemptyset(&ss) < 0) { 74 daemon_log(LOG_ERR, "sigemptyset(): %s", strerror(errno)); 75 return -1; 76 } 77 78 if (sigaddset(&ss, s) < 0) { 79 daemon_log(LOG_ERR, "sigaddset(): %s", strerror(errno)); 80 return -1; 81 } 82 83 if (sigprocmask(SIG_UNBLOCK, &ss, NULL) < 0) { 84 daemon_log(LOG_ERR, "sigprocmask(): %s", strerror(errno)); 85 return -1; 86 } 87 88 memset(&sa, 0, sizeof(sa)); 89 sa.sa_handler = _sigfunc; 90 sigemptyset(&sa.sa_mask); 91 sa.sa_flags = SA_RESTART; 92 93 if (sigaction(s, &sa, NULL) < 0) { 94 daemon_log(LOG_ERR, "sigaction(%s, ...) failed: %s", strsignal(s), strerror(errno)); 95 return -1; 96 } 97 98 return 0; 99 } 100 101 int daemon_signal_init(int s, ...) { 102 int sig, r = 0; 103 va_list ap; 104 105 if (_init() < 0) 106 return -1; 107 108 va_start(ap, s); 109 110 sig = s; 111 while (sig > 0) { 112 if ((r = daemon_signal_install(sig)) < 0) 113 break; 114 115 sig = va_arg(ap, int); 116 } 117 118 va_end(ap); 119 120 return r; 121 } 122 123 void daemon_signal_done(void) { 124 int saved_errno = errno; 125 126 if (_signal_pipe[0] != -1) 127 close(_signal_pipe[0]); 128 129 if (_signal_pipe[1] != -1) 130 close(_signal_pipe[1]); 131 132 _signal_pipe[0] = _signal_pipe[1] = -1; 133 134 errno = saved_errno; 135 } 136 137 int daemon_signal_next(void) { 138 int s; 139 ssize_t r; 140 141 if ((r = read(_signal_pipe[0], &s, sizeof(s))) == sizeof(s)) 142 return s; 143 144 if (r < 0) { 145 146 if (errno == EAGAIN) 147 return 0; 148 else { 149 daemon_log(LOG_ERR, "read(signal_pipe[0], ...): %s", strerror(errno)); 150 return -1; 151 } 152 } 153 154 daemon_log(LOG_ERR, "Short read() on signal pipe."); 155 return -1; 156 } 157 158 int daemon_signal_fd(void) { 159 return _signal_pipe[0]; 160 } 161