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 hook_remove(struct hookproc *hp); 86 static void hook_free(struct hookproc *hp); 87 88 static void 89 descriptors(void) 90 { 91 int fd; 92 93 /* 94 * Close all (or almost all) descriptors. 95 */ 96 if (pjdlog_mode_get() == PJDLOG_MODE_STD) { 97 closefrom(MAX(MAX(STDIN_FILENO, STDOUT_FILENO), 98 STDERR_FILENO) + 1); 99 return; 100 } 101 102 closefrom(0); 103 104 /* 105 * Redirect stdin, stdout and stderr to /dev/null. 106 */ 107 fd = open(_PATH_DEVNULL, O_RDONLY); 108 if (fd < 0) { 109 pjdlog_errno(LOG_WARNING, "Unable to open %s for reading", 110 _PATH_DEVNULL); 111 } else if (fd != STDIN_FILENO) { 112 if (dup2(fd, STDIN_FILENO) < 0) { 113 pjdlog_errno(LOG_WARNING, 114 "Unable to duplicate descriptor for stdin"); 115 } 116 close(fd); 117 } 118 fd = open(_PATH_DEVNULL, O_WRONLY); 119 if (fd < 0) { 120 pjdlog_errno(LOG_WARNING, "Unable to open %s for writing", 121 _PATH_DEVNULL); 122 } else { 123 if (fd != STDOUT_FILENO && dup2(fd, STDOUT_FILENO) < 0) { 124 pjdlog_errno(LOG_WARNING, 125 "Unable to duplicate descriptor for stdout"); 126 } 127 if (fd != STDERR_FILENO && dup2(fd, STDERR_FILENO) < 0) { 128 pjdlog_errno(LOG_WARNING, 129 "Unable to duplicate descriptor for stderr"); 130 } 131 if (fd != STDOUT_FILENO && fd != STDERR_FILENO) 132 close(fd); 133 } 134 } 135 136 void 137 hook_init(void) 138 { 139 140 assert(!hooks_initialized); 141 142 mtx_init(&hookprocs_lock); 143 TAILQ_INIT(&hookprocs); 144 hooks_initialized = true; 145 } 146 147 void 148 hook_fini(void) 149 { 150 struct hookproc *hp; 151 152 assert(hooks_initialized); 153 154 mtx_lock(&hookprocs_lock); 155 while ((hp = TAILQ_FIRST(&hookprocs)) != NULL) { 156 assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 157 assert(hp->hp_pid > 0); 158 159 hook_remove(hp); 160 hook_free(hp); 161 } 162 mtx_unlock(&hookprocs_lock); 163 164 mtx_destroy(&hookprocs_lock); 165 TAILQ_INIT(&hookprocs); 166 hooks_initialized = false; 167 } 168 169 static struct hookproc * 170 hook_alloc(const char *path, char **args) 171 { 172 struct hookproc *hp; 173 unsigned int ii; 174 175 hp = malloc(sizeof(*hp)); 176 if (hp == NULL) { 177 pjdlog_error("Unable to allocate %zu bytes of memory for a hook.", 178 sizeof(*hp)); 179 return (NULL); 180 } 181 182 hp->hp_pid = 0; 183 hp->hp_birthtime = hp->hp_lastreport = time(NULL); 184 (void)strlcpy(hp->hp_comm, path, sizeof(hp->hp_comm)); 185 /* We start at 2nd argument as we don't want to have exec name twice. */ 186 for (ii = 1; args[ii] != NULL; ii++) { 187 (void)strlcat(hp->hp_comm, " ", sizeof(hp->hp_comm)); 188 (void)strlcat(hp->hp_comm, args[ii], sizeof(hp->hp_comm)); 189 } 190 if (strlen(hp->hp_comm) >= sizeof(hp->hp_comm) - 1) { 191 pjdlog_error("Exec path too long, correct configuration file."); 192 free(hp); 193 return (NULL); 194 } 195 hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 196 return (hp); 197 } 198 199 static void 200 hook_add(struct hookproc *hp, pid_t pid) 201 { 202 203 assert(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 204 assert(hp->hp_pid == 0); 205 206 hp->hp_pid = pid; 207 mtx_lock(&hookprocs_lock); 208 hp->hp_magic = HOOKPROC_MAGIC_ONLIST; 209 TAILQ_INSERT_TAIL(&hookprocs, hp, hp_next); 210 mtx_unlock(&hookprocs_lock); 211 } 212 213 static void 214 hook_remove(struct hookproc *hp) 215 { 216 217 assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 218 assert(hp->hp_pid > 0); 219 assert(mtx_owned(&hookprocs_lock)); 220 221 TAILQ_REMOVE(&hookprocs, hp, hp_next); 222 hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 223 } 224 225 static void 226 hook_free(struct hookproc *hp) 227 { 228 229 assert(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 230 assert(hp->hp_pid > 0); 231 232 hp->hp_magic = 0; 233 free(hp); 234 } 235 236 static struct hookproc * 237 hook_find(pid_t pid) 238 { 239 struct hookproc *hp; 240 241 assert(mtx_owned(&hookprocs_lock)); 242 243 TAILQ_FOREACH(hp, &hookprocs, hp_next) { 244 assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 245 assert(hp->hp_pid > 0); 246 247 if (hp->hp_pid == pid) 248 break; 249 } 250 251 return (hp); 252 } 253 254 void 255 hook_check_one(pid_t pid, int status) 256 { 257 struct hookproc *hp; 258 259 mtx_lock(&hookprocs_lock); 260 hp = hook_find(pid); 261 if (hp == NULL) { 262 mtx_unlock(&hookprocs_lock); 263 pjdlog_debug(1, "Unknown process pid=%u", pid); 264 return; 265 } 266 hook_remove(hp); 267 mtx_unlock(&hookprocs_lock); 268 if (WIFEXITED(status) && WEXITSTATUS(status) == 0) { 269 pjdlog_debug(1, "Hook exited gracefully (pid=%u, cmd=[%s]).", 270 pid, hp->hp_comm); 271 } else if (WIFSIGNALED(status)) { 272 pjdlog_error("Hook was killed (pid=%u, signal=%d, cmd=[%s]).", 273 pid, WTERMSIG(status), hp->hp_comm); 274 } else { 275 pjdlog_error("Hook exited ungracefully (pid=%u, exitcode=%d, cmd=[%s]).", 276 pid, WIFEXITED(status) ? WEXITSTATUS(status) : -1, 277 hp->hp_comm); 278 } 279 hook_free(hp); 280 } 281 282 void 283 hook_check(void) 284 { 285 struct hookproc *hp, *hp2; 286 time_t now; 287 288 assert(hooks_initialized); 289 290 /* 291 * Report about processes that are running for a long time. 292 */ 293 now = time(NULL); 294 mtx_lock(&hookprocs_lock); 295 TAILQ_FOREACH_SAFE(hp, &hookprocs, hp_next, hp2) { 296 assert(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 297 assert(hp->hp_pid > 0); 298 299 /* 300 * If process doesn't exists we somehow missed it. 301 * Not much can be done expect for logging this situation. 302 */ 303 if (kill(hp->hp_pid, 0) == -1 && errno == ESRCH) { 304 pjdlog_warning("Hook disappeared (pid=%u, cmd=[%s]).", 305 hp->hp_pid, hp->hp_comm); 306 hook_remove(hp); 307 hook_free(hp); 308 continue; 309 } 310 311 /* 312 * Skip proccesses younger than 1 minute. 313 */ 314 if (now - hp->hp_lastreport < REPORT_INTERVAL) 315 continue; 316 317 /* 318 * Hook is running for too long, report it. 319 */ 320 pjdlog_warning("Hook is running for %ju seconds (pid=%u, cmd=[%s]).", 321 (uintmax_t)(now - hp->hp_birthtime), hp->hp_pid, 322 hp->hp_comm); 323 hp->hp_lastreport = now; 324 } 325 mtx_unlock(&hookprocs_lock); 326 } 327 328 void 329 hook_exec(const char *path, ...) 330 { 331 va_list ap; 332 333 va_start(ap, path); 334 hook_execv(path, ap); 335 va_end(ap); 336 } 337 338 void 339 hook_execv(const char *path, va_list ap) 340 { 341 struct hookproc *hp; 342 char *args[64]; 343 unsigned int ii; 344 sigset_t mask; 345 pid_t pid; 346 347 assert(hooks_initialized); 348 349 if (path == NULL || path[0] == '\0') 350 return; 351 352 memset(args, 0, sizeof(args)); 353 args[0] = basename(path); 354 for (ii = 1; ii < sizeof(args) / sizeof(args[0]); ii++) { 355 args[ii] = va_arg(ap, char *); 356 if (args[ii] == NULL) 357 break; 358 } 359 assert(ii < sizeof(args) / sizeof(args[0])); 360 361 hp = hook_alloc(path, args); 362 if (hp == NULL) 363 return; 364 365 pid = fork(); 366 switch (pid) { 367 case -1: /* Error. */ 368 pjdlog_errno(LOG_ERR, "Unable to fork to execute %s", path); 369 hook_free(hp); 370 return; 371 case 0: /* Child. */ 372 descriptors(); 373 PJDLOG_VERIFY(sigemptyset(&mask) == 0); 374 PJDLOG_VERIFY(sigprocmask(SIG_SETMASK, &mask, NULL) == 0); 375 execv(path, args); 376 pjdlog_errno(LOG_ERR, "Unable to execute %s", path); 377 exit(EX_SOFTWARE); 378 default: /* Parent. */ 379 hook_add(hp, pid); 380 break; 381 } 382 } 383