1 /* 2 * This file is part of the ZFS Event Daemon (ZED). 3 * 4 * Developed at Lawrence Livermore National Laboratory (LLNL-CODE-403049). 5 * Copyright (C) 2013-2014 Lawrence Livermore National Security, LLC. 6 * Refer to the OpenZFS git commit log for authoritative copyright attribution. 7 * 8 * The contents of this file are subject to the terms of the 9 * Common Development and Distribution License Version 1.0 (CDDL-1.0). 10 * You can obtain a copy of the license from the top-level file 11 * "OPENSOLARIS.LICENSE" or at <http://opensource.org/licenses/CDDL-1.0>. 12 * You may not use this file except in compliance with the license. 13 */ 14 15 #include <errno.h> 16 #include <fcntl.h> 17 #include <signal.h> 18 #include <stdio.h> 19 #include <stdlib.h> 20 #include <string.h> 21 #include <sys/mman.h> 22 #include <sys/stat.h> 23 #include <unistd.h> 24 #include "zed.h" 25 #include "zed_conf.h" 26 #include "zed_event.h" 27 #include "zed_file.h" 28 #include "zed_log.h" 29 30 static volatile sig_atomic_t _got_exit = 0; 31 static volatile sig_atomic_t _got_hup = 0; 32 33 /* 34 * Signal handler for SIGINT & SIGTERM. 35 */ 36 static void 37 _exit_handler(int signum) 38 { 39 _got_exit = 1; 40 } 41 42 /* 43 * Signal handler for SIGHUP. 44 */ 45 static void 46 _hup_handler(int signum) 47 { 48 _got_hup = 1; 49 } 50 51 /* 52 * Register signal handlers. 53 */ 54 static void 55 _setup_sig_handlers(void) 56 { 57 struct sigaction sa; 58 59 if (sigemptyset(&sa.sa_mask) < 0) 60 zed_log_die("Failed to initialize sigset"); 61 62 sa.sa_flags = SA_RESTART; 63 64 sa.sa_handler = SIG_IGN; 65 if (sigaction(SIGPIPE, &sa, NULL) < 0) 66 zed_log_die("Failed to ignore SIGPIPE"); 67 68 sa.sa_handler = _exit_handler; 69 if (sigaction(SIGINT, &sa, NULL) < 0) 70 zed_log_die("Failed to register SIGINT handler"); 71 72 if (sigaction(SIGTERM, &sa, NULL) < 0) 73 zed_log_die("Failed to register SIGTERM handler"); 74 75 sa.sa_handler = _hup_handler; 76 if (sigaction(SIGHUP, &sa, NULL) < 0) 77 zed_log_die("Failed to register SIGHUP handler"); 78 79 (void) sigaddset(&sa.sa_mask, SIGCHLD); 80 if (pthread_sigmask(SIG_BLOCK, &sa.sa_mask, NULL) < 0) 81 zed_log_die("Failed to block SIGCHLD"); 82 } 83 84 /* 85 * Lock all current and future pages in the virtual memory address space. 86 * Access to locked pages will never be delayed by a page fault. 87 * 88 * EAGAIN is tested up to max_tries in case this is a transient error. 89 * 90 * Note that memory locks are not inherited by a child created via fork() 91 * and are automatically removed during an execve(). As such, this must 92 * be called after the daemon fork()s (when running in the background). 93 */ 94 static void 95 _lock_memory(void) 96 { 97 #if HAVE_MLOCKALL 98 int i = 0; 99 const int max_tries = 10; 100 101 for (i = 0; i < max_tries; i++) { 102 if (mlockall(MCL_CURRENT | MCL_FUTURE) == 0) { 103 zed_log_msg(LOG_INFO, "Locked all pages in memory"); 104 return; 105 } 106 if (errno != EAGAIN) 107 break; 108 } 109 zed_log_die("Failed to lock memory pages: %s", strerror(errno)); 110 111 #else /* HAVE_MLOCKALL */ 112 zed_log_die("Failed to lock memory pages: mlockall() not supported"); 113 #endif /* HAVE_MLOCKALL */ 114 } 115 116 /* 117 * Start daemonization of the process including the double fork(). 118 * 119 * The parent process will block here until _finish_daemonize() is called 120 * (in the grandchild process), at which point the parent process will exit. 121 * This prevents the parent process from exiting until initialization is 122 * complete. 123 */ 124 static void 125 _start_daemonize(void) 126 { 127 pid_t pid; 128 struct sigaction sa; 129 130 /* Create pipe for communicating with child during daemonization. */ 131 zed_log_pipe_open(); 132 133 /* Background process and ensure child is not process group leader. */ 134 pid = fork(); 135 if (pid < 0) { 136 zed_log_die("Failed to create child process: %s", 137 strerror(errno)); 138 } else if (pid > 0) { 139 140 /* Close writes since parent will only read from pipe. */ 141 zed_log_pipe_close_writes(); 142 143 /* Wait for notification that daemonization is complete. */ 144 zed_log_pipe_wait(); 145 146 zed_log_pipe_close_reads(); 147 _exit(EXIT_SUCCESS); 148 } 149 150 /* Close reads since child will only write to pipe. */ 151 zed_log_pipe_close_reads(); 152 153 /* Create independent session and detach from terminal. */ 154 if (setsid() < 0) 155 zed_log_die("Failed to create new session: %s", 156 strerror(errno)); 157 158 /* Prevent child from terminating on HUP when session leader exits. */ 159 if (sigemptyset(&sa.sa_mask) < 0) 160 zed_log_die("Failed to initialize sigset"); 161 162 sa.sa_flags = 0; 163 sa.sa_handler = SIG_IGN; 164 165 if (sigaction(SIGHUP, &sa, NULL) < 0) 166 zed_log_die("Failed to ignore SIGHUP"); 167 168 /* Ensure process cannot re-acquire terminal. */ 169 pid = fork(); 170 if (pid < 0) { 171 zed_log_die("Failed to create grandchild process: %s", 172 strerror(errno)); 173 } else if (pid > 0) { 174 _exit(EXIT_SUCCESS); 175 } 176 } 177 178 /* 179 * Finish daemonization of the process by closing stdin/stdout/stderr. 180 * 181 * This must be called at the end of initialization after all external 182 * communication channels are established and accessible. 183 */ 184 static void 185 _finish_daemonize(void) 186 { 187 int devnull; 188 189 /* Preserve fd 0/1/2, but discard data to/from stdin/stdout/stderr. */ 190 devnull = open("/dev/null", O_RDWR); 191 if (devnull < 0) 192 zed_log_die("Failed to open /dev/null: %s", strerror(errno)); 193 194 if (dup2(devnull, STDIN_FILENO) < 0) 195 zed_log_die("Failed to dup /dev/null onto stdin: %s", 196 strerror(errno)); 197 198 if (dup2(devnull, STDOUT_FILENO) < 0) 199 zed_log_die("Failed to dup /dev/null onto stdout: %s", 200 strerror(errno)); 201 202 if (dup2(devnull, STDERR_FILENO) < 0) 203 zed_log_die("Failed to dup /dev/null onto stderr: %s", 204 strerror(errno)); 205 206 if ((devnull > STDERR_FILENO) && (close(devnull) < 0)) 207 zed_log_die("Failed to close /dev/null: %s", strerror(errno)); 208 209 /* Notify parent that daemonization is complete. */ 210 zed_log_pipe_close_writes(); 211 } 212 213 /* 214 * ZFS Event Daemon (ZED). 215 */ 216 int 217 main(int argc, char *argv[]) 218 { 219 struct zed_conf zcp; 220 uint64_t saved_eid; 221 int64_t saved_etime[2]; 222 223 zed_log_init(argv[0]); 224 zed_log_stderr_open(LOG_NOTICE); 225 zed_conf_init(&zcp); 226 zed_conf_parse_opts(&zcp, argc, argv); 227 if (zcp.do_verbose) 228 zed_log_stderr_open(LOG_INFO); 229 230 if (geteuid() != 0) 231 zed_log_die("Must be run as root"); 232 233 zed_file_close_from(STDERR_FILENO + 1); 234 235 (void) umask(0); 236 237 if (chdir("/") < 0) 238 zed_log_die("Failed to change to root directory"); 239 240 if (zed_conf_scan_dir(&zcp) < 0) 241 exit(EXIT_FAILURE); 242 243 if (!zcp.do_foreground) { 244 _start_daemonize(); 245 zed_log_syslog_open(LOG_DAEMON); 246 } 247 _setup_sig_handlers(); 248 249 if (zcp.do_memlock) 250 _lock_memory(); 251 252 if ((zed_conf_write_pid(&zcp) < 0) && (!zcp.do_force)) 253 exit(EXIT_FAILURE); 254 255 if (!zcp.do_foreground) 256 _finish_daemonize(); 257 258 zed_log_msg(LOG_NOTICE, 259 "ZFS Event Daemon %s-%s (PID %d)", 260 ZFS_META_VERSION, ZFS_META_RELEASE, (int)getpid()); 261 262 if (zed_conf_open_state(&zcp) < 0) 263 exit(EXIT_FAILURE); 264 265 if (zed_conf_read_state(&zcp, &saved_eid, saved_etime) < 0) 266 exit(EXIT_FAILURE); 267 268 idle: 269 /* 270 * If -I is specified, attempt to open /dev/zfs repeatedly until 271 * successful. 272 */ 273 do { 274 if (!zed_event_init(&zcp)) 275 break; 276 /* Wait for some time and try again. tunable? */ 277 sleep(30); 278 } while (!_got_exit && zcp.do_idle); 279 280 if (_got_exit) 281 goto out; 282 283 zed_event_seek(&zcp, saved_eid, saved_etime); 284 285 while (!_got_exit) { 286 int rv; 287 if (_got_hup) { 288 _got_hup = 0; 289 (void) zed_conf_scan_dir(&zcp); 290 } 291 rv = zed_event_service(&zcp); 292 293 /* ENODEV: When kernel module is unloaded (osx) */ 294 if (rv != 0) 295 break; 296 } 297 298 zed_log_msg(LOG_NOTICE, "Exiting"); 299 zed_event_fini(&zcp); 300 301 if (zcp.do_idle && !_got_exit) 302 goto idle; 303 304 out: 305 zed_conf_destroy(&zcp); 306 zed_log_fini(); 307 exit(EXIT_SUCCESS); 308 } 309