1 /*- 2 * Copyright (c) 2010 The FreeBSD Foundation 3 * Copyright (c) 2010 Pawel Jakub Dawidek <pjd@FreeBSD.org> 4 * All rights reserved. 5 * 6 * This software was developed by Pawel Jakub Dawidek under sponsorship from 7 * the FreeBSD Foundation. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in the 16 * documentation and/or other materials provided with the distribution. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/types.h> 35 #include <sys/sysctl.h> 36 #include <sys/wait.h> 37 38 #include <assert.h> 39 #include <errno.h> 40 #include <fcntl.h> 41 #include <libgen.h> 42 #include <paths.h> 43 #include <signal.h> 44 #include <stdbool.h> 45 #include <stdint.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 #include <syslog.h> 50 #include <unistd.h> 51 52 #include <pjdlog.h> 53 54 #include "hooks.h" 55 #include "synch.h" 56 57 /* Report processes that are running for too long not often than this value. */ 58 #define REPORT_INTERVAL 60 59 60 /* Are we initialized? */ 61 static bool hooks_initialized = false; 62 63 /* 64 * Keep all processes we forked on a global queue, so we can report nicely 65 * when they finish or report that they are running for a long time. 66 */ 67 #define HOOKPROC_MAGIC_ALLOCATED 0x80090ca 68 #define HOOKPROC_MAGIC_ONLIST 0x80090c0 69 struct hookproc { 70 /* Magic. */ 71 int hp_magic; 72 /* PID of a forked child. */ 73 pid_t hp_pid; 74 /* When process were forked? */ 75 time_t hp_birthtime; 76 /* When we logged previous reported? */ 77 time_t hp_lastreport; 78 /* Path to executable and all the arguments we passed. */ 79 char hp_comm[PATH_MAX]; 80 TAILQ_ENTRY(hookproc) hp_next; 81 }; 82 static TAILQ_HEAD(, hookproc) hookprocs; 83 static pthread_mutex_t hookprocs_lock; 84 85 static void 86 descriptors(void) 87 { 88 long maxfd; 89 int fd; 90 91 /* 92 * Close all descriptors. 93 */ 94 maxfd = sysconf(_SC_OPEN_MAX); 95 if (maxfd < 0) { 96 pjdlog_errno(LOG_WARNING, "sysconf(_SC_OPEN_MAX) failed"); 97 maxfd = 1024; 98 } 99 for (fd = 0; fd <= maxfd; fd++) { 100 switch (fd) { 101 case STDIN_FILENO: 102 case STDOUT_FILENO: 103 case STDERR_FILENO: 104 if (pjdlog_mode_get() == PJDLOG_MODE_STD) 105 break; 106 /* FALLTHROUGH */ 107 default: 108 close(fd); 109 break; 110 } 111 } 112 if (pjdlog_mode_get() == PJDLOG_MODE_STD) 113 return; 114 /* 115 * Redirect stdin, stdout and stderr to /dev/null. 116 */ 117 fd = open(_PATH_DEVNULL, O_RDONLY); 118 if (fd < 0) { 119 pjdlog_errno(LOG_WARNING, "Unable to open %s for reading", 120 _PATH_DEVNULL); 121 } else if (fd != STDIN_FILENO) { 122 if (dup2(fd, STDIN_FILENO) < 0) { 123 pjdlog_errno(LOG_WARNING, 124 "Unable to duplicate descriptor for stdin"); 125 } 126 close(fd); 127 } 128 fd = open(_PATH_DEVNULL, O_WRONLY); 129 if (fd < 0) { 130 pjdlog_errno(LOG_WARNING, "Unable to open %s for writing", 131 _PATH_DEVNULL); 132 } else { 133 if (fd != STDOUT_FILENO && dup2(fd, STDOUT_FILENO) < 0) { 134 pjdlog_errno(LOG_WARNING, 135 "Unable to duplicate descriptor for stdout"); 136 } 137 if (fd != STDERR_FILENO && dup2(fd, STDERR_FILENO) < 0) { 138 pjdlog_errno(LOG_WARNING, 139 "Unable to duplicate descriptor for stderr"); 140 } 141 if (fd != STDOUT_FILENO && fd != STDERR_FILENO) 142 close(fd); 143 } 144 } 145 146 void 147 hook_init(void) 148 { 149 150 mtx_init(&hookprocs_lock); 151 TAILQ_INIT(&hookprocs); 152 hooks_initialized = true; 153 } 154 155 static struct hookproc * 156 hook_alloc(const char *path, char **args) 157 { 158 struct hookproc *hp; 159 unsigned int ii; 160 161 hp = malloc(sizeof(*hp)); 162 if (hp == NULL) { 163 pjdlog_error("Unable to allocate %zu bytes of memory for a hook.", 164 sizeof(*hp)); 165 return (NULL); 166 } 167 168 hp->hp_pid = 0; 169 hp->hp_birthtime = hp->hp_lastreport = time(NULL); 170 (void)strlcpy(hp->hp_comm, path, sizeof(hp->hp_comm)); 171 /* We start at 2nd argument as we don't want to have exec name twice. */ 172 for (ii = 1; args[ii] != NULL; ii++) { 173 (void)strlcat(hp->hp_comm, " ", sizeof(hp->hp_comm)); 174 (void)strlcat(hp->hp_comm, args[ii], sizeof(hp->hp_comm)); 175 } 176 if (strlen(hp->hp_comm) >= sizeof(hp->hp_comm) - 1) { 177 pjdlog_error("Exec path too long, correct configuration file."); 178 free(hp); 179 return (NULL); 180 } 181 hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 182 return (hp); 183 } 184 185 static void 186 hook_add(struct hookproc *hp, pid_t pid) 187 { 188 189 assert(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 190 assert(hp->hp_pid == 0); 191 192 hp->hp_pid = pid; 193 mtx_lock(&hookprocs_lock); 194 hp->hp_magic = HOOKPROC_MAGIC_ONLIST; 195 TAILQ_INSERT_TAIL(&hookprocs, hp, hp_next); 196 mtx_unlock(&hookprocs_lock); 197 } 198 199 static void 200 hook_remove(struct hookproc *hp) 201 { 202 203 assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 204 assert(hp->hp_pid > 0); 205 assert(mtx_owned(&hookprocs_lock)); 206 207 TAILQ_REMOVE(&hookprocs, hp, hp_next); 208 hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 209 } 210 211 static void 212 hook_free(struct hookproc *hp) 213 { 214 215 assert(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 216 assert(hp->hp_pid > 0); 217 218 hp->hp_magic = 0; 219 free(hp); 220 } 221 222 static struct hookproc * 223 hook_find(pid_t pid) 224 { 225 struct hookproc *hp; 226 227 assert(mtx_owned(&hookprocs_lock)); 228 229 TAILQ_FOREACH(hp, &hookprocs, hp_next) { 230 assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 231 assert(hp->hp_pid > 0); 232 233 if (hp->hp_pid == pid) 234 break; 235 } 236 237 return (hp); 238 } 239 240 void 241 hook_check(bool sigchld) 242 { 243 struct hookproc *hp, *hp2; 244 int status; 245 time_t now; 246 pid_t pid; 247 248 assert(hooks_initialized); 249 250 /* 251 * If SIGCHLD was received, garbage collect finished processes. 252 */ 253 while (sigchld && (pid = wait3(&status, WNOHANG, NULL)) > 0) { 254 mtx_lock(&hookprocs_lock); 255 hp = hook_find(pid); 256 if (hp == NULL) { 257 mtx_unlock(&hookprocs_lock); 258 pjdlog_warning("Unknown process pid=%u", pid); 259 continue; 260 } 261 hook_remove(hp); 262 mtx_unlock(&hookprocs_lock); 263 if (WIFEXITED(status) && WEXITSTATUS(status) == 0) { 264 pjdlog_debug(1, "Hook exited gracefully (pid=%u, cmd=[%s]).", 265 pid, hp->hp_comm); 266 } else if (WIFSIGNALED(status)) { 267 pjdlog_error("Hook was killed (pid=%u, signal=%d, cmd=[%s]).", 268 pid, WTERMSIG(status), hp->hp_comm); 269 } else { 270 pjdlog_error("Hook exited ungracefully (pid=%u, exitcode=%d, cmd=[%s]).", 271 pid, WIFEXITED(status) ? WEXITSTATUS(status) : -1, 272 hp->hp_comm); 273 } 274 hook_free(hp); 275 } 276 277 /* 278 * Report about processes that are running for a long time. 279 */ 280 now = time(NULL); 281 mtx_lock(&hookprocs_lock); 282 TAILQ_FOREACH_SAFE(hp, &hookprocs, hp_next, hp2) { 283 assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 284 assert(hp->hp_pid > 0); 285 286 /* 287 * If process doesn't exists we somehow missed it. 288 * Not much can be done expect for logging this situation. 289 */ 290 if (kill(hp->hp_pid, 0) == -1 && errno == ESRCH) { 291 pjdlog_warning("Hook disappeared (pid=%u, cmd=[%s]).", 292 hp->hp_pid, hp->hp_comm); 293 hook_remove(hp); 294 hook_free(hp); 295 continue; 296 } 297 298 /* 299 * Skip proccesses younger than 1 minute. 300 */ 301 if (now - hp->hp_lastreport < REPORT_INTERVAL) 302 continue; 303 304 /* 305 * Hook is running for too long, report it. 306 */ 307 pjdlog_warning("Hook is running for %ju seconds (pid=%u, cmd=[%s]).", 308 (uintmax_t)(now - hp->hp_birthtime), hp->hp_pid, 309 hp->hp_comm); 310 hp->hp_lastreport = now; 311 } 312 mtx_unlock(&hookprocs_lock); 313 } 314 315 void 316 hook_exec(const char *path, ...) 317 { 318 va_list ap; 319 320 va_start(ap, path); 321 hook_execv(path, ap); 322 va_end(ap); 323 } 324 325 void 326 hook_execv(const char *path, va_list ap) 327 { 328 struct hookproc *hp; 329 char *args[64]; 330 unsigned int ii; 331 pid_t pid; 332 333 assert(hooks_initialized); 334 335 if (path == NULL || path[0] == '\0') 336 return; 337 338 memset(args, 0, sizeof(args)); 339 args[0] = basename(path); 340 for (ii = 1; ii < sizeof(args) / sizeof(args[0]); ii++) { 341 args[ii] = va_arg(ap, char *); 342 if (args[ii] == NULL) 343 break; 344 } 345 assert(ii < sizeof(args) / sizeof(args[0])); 346 347 hp = hook_alloc(path, args); 348 if (hp == NULL) 349 return; 350 351 pid = fork(); 352 switch (pid) { 353 case -1: /* Error. */ 354 pjdlog_errno(LOG_ERR, "Unable to fork to execute %s", path); 355 return; 356 case 0: /* Child. */ 357 descriptors(); 358 execv(path, args); 359 pjdlog_errno(LOG_ERR, "Unable to execute %s", path); 360 exit(EX_SOFTWARE); 361 default: /* Parent. */ 362 hook_add(hp, pid); 363 break; 364 } 365 } 366