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 <errno.h> 39 #include <fcntl.h> 40 #include <paths.h> 41 #include <signal.h> 42 #include <stdbool.h> 43 #include <stdint.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <syslog.h> 48 #include <unistd.h> 49 50 #include <pjdlog.h> 51 52 #include "hooks.h" 53 #include "subr.h" 54 #include "synch.h" 55 56 /* Report processes that are running for too long not often than this value. */ 57 #define REPORT_INTERVAL 60 58 59 /* Are we initialized? */ 60 static bool hooks_initialized = false; 61 62 /* 63 * Keep all processes we forked on a global queue, so we can report nicely 64 * when they finish or report that they are running for a long time. 65 */ 66 #define HOOKPROC_MAGIC_ALLOCATED 0x80090ca 67 #define HOOKPROC_MAGIC_ONLIST 0x80090c0 68 struct hookproc { 69 /* Magic. */ 70 int hp_magic; 71 /* PID of a forked child. */ 72 pid_t hp_pid; 73 /* When process were forked? */ 74 time_t hp_birthtime; 75 /* When we logged previous reported? */ 76 time_t hp_lastreport; 77 /* Path to executable and all the arguments we passed. */ 78 char hp_comm[PATH_MAX]; 79 TAILQ_ENTRY(hookproc) hp_next; 80 }; 81 static TAILQ_HEAD(, hookproc) hookprocs; 82 static pthread_mutex_t hookprocs_lock; 83 84 static void hook_remove(struct hookproc *hp); 85 static void hook_free(struct hookproc *hp); 86 87 static void 88 descriptors(void) 89 { 90 int fd; 91 92 /* 93 * Close all (or almost all) descriptors. 94 */ 95 if (pjdlog_mode_get() == PJDLOG_MODE_STD) { 96 closefrom(MAX(MAX(STDIN_FILENO, STDOUT_FILENO), 97 STDERR_FILENO) + 1); 98 return; 99 } 100 101 closefrom(0); 102 103 /* 104 * Redirect stdin, stdout and stderr to /dev/null. 105 */ 106 fd = open(_PATH_DEVNULL, O_RDONLY); 107 if (fd == -1) { 108 pjdlog_errno(LOG_WARNING, "Unable to open %s for reading", 109 _PATH_DEVNULL); 110 } else if (fd != STDIN_FILENO) { 111 if (dup2(fd, STDIN_FILENO) == -1) { 112 pjdlog_errno(LOG_WARNING, 113 "Unable to duplicate descriptor for stdin"); 114 } 115 close(fd); 116 } 117 fd = open(_PATH_DEVNULL, O_WRONLY); 118 if (fd == -1) { 119 pjdlog_errno(LOG_WARNING, "Unable to open %s for writing", 120 _PATH_DEVNULL); 121 } else { 122 if (fd != STDOUT_FILENO && dup2(fd, STDOUT_FILENO) == -1) { 123 pjdlog_errno(LOG_WARNING, 124 "Unable to duplicate descriptor for stdout"); 125 } 126 if (fd != STDERR_FILENO && dup2(fd, STDERR_FILENO) == -1) { 127 pjdlog_errno(LOG_WARNING, 128 "Unable to duplicate descriptor for stderr"); 129 } 130 if (fd != STDOUT_FILENO && fd != STDERR_FILENO) 131 close(fd); 132 } 133 } 134 135 void 136 hook_init(void) 137 { 138 139 PJDLOG_ASSERT(!hooks_initialized); 140 141 mtx_init(&hookprocs_lock); 142 TAILQ_INIT(&hookprocs); 143 hooks_initialized = true; 144 } 145 146 void 147 hook_fini(void) 148 { 149 struct hookproc *hp; 150 151 PJDLOG_ASSERT(hooks_initialized); 152 153 mtx_lock(&hookprocs_lock); 154 while ((hp = TAILQ_FIRST(&hookprocs)) != NULL) { 155 PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 156 PJDLOG_ASSERT(hp->hp_pid > 0); 157 158 hook_remove(hp); 159 hook_free(hp); 160 } 161 mtx_unlock(&hookprocs_lock); 162 163 mtx_destroy(&hookprocs_lock); 164 TAILQ_INIT(&hookprocs); 165 hooks_initialized = false; 166 } 167 168 static struct hookproc * 169 hook_alloc(const char *path, char **args) 170 { 171 struct hookproc *hp; 172 unsigned int ii; 173 174 hp = malloc(sizeof(*hp)); 175 if (hp == NULL) { 176 pjdlog_error("Unable to allocate %zu bytes of memory for a hook.", 177 sizeof(*hp)); 178 return (NULL); 179 } 180 181 hp->hp_pid = 0; 182 hp->hp_birthtime = hp->hp_lastreport = time(NULL); 183 (void)strlcpy(hp->hp_comm, path, sizeof(hp->hp_comm)); 184 /* We start at 2nd argument as we don't want to have exec name twice. */ 185 for (ii = 1; args[ii] != NULL; ii++) { 186 (void)snprlcat(hp->hp_comm, sizeof(hp->hp_comm), " %s", 187 args[ii]); 188 } 189 if (strlen(hp->hp_comm) >= sizeof(hp->hp_comm) - 1) { 190 pjdlog_error("Exec path too long, correct configuration file."); 191 free(hp); 192 return (NULL); 193 } 194 hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 195 return (hp); 196 } 197 198 static void 199 hook_add(struct hookproc *hp, pid_t pid) 200 { 201 202 PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 203 PJDLOG_ASSERT(hp->hp_pid == 0); 204 205 hp->hp_pid = pid; 206 mtx_lock(&hookprocs_lock); 207 hp->hp_magic = HOOKPROC_MAGIC_ONLIST; 208 TAILQ_INSERT_TAIL(&hookprocs, hp, hp_next); 209 mtx_unlock(&hookprocs_lock); 210 } 211 212 static void 213 hook_remove(struct hookproc *hp) 214 { 215 216 PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 217 PJDLOG_ASSERT(hp->hp_pid > 0); 218 PJDLOG_ASSERT(mtx_owned(&hookprocs_lock)); 219 220 TAILQ_REMOVE(&hookprocs, hp, hp_next); 221 hp->hp_magic = HOOKPROC_MAGIC_ALLOCATED; 222 } 223 224 static void 225 hook_free(struct hookproc *hp) 226 { 227 228 PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ALLOCATED); 229 PJDLOG_ASSERT(hp->hp_pid > 0); 230 231 hp->hp_magic = 0; 232 free(hp); 233 } 234 235 static struct hookproc * 236 hook_find(pid_t pid) 237 { 238 struct hookproc *hp; 239 240 PJDLOG_ASSERT(mtx_owned(&hookprocs_lock)); 241 242 TAILQ_FOREACH(hp, &hookprocs, hp_next) { 243 PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 244 PJDLOG_ASSERT(hp->hp_pid > 0); 245 246 if (hp->hp_pid == pid) 247 break; 248 } 249 250 return (hp); 251 } 252 253 void 254 hook_check_one(pid_t pid, int status) 255 { 256 struct hookproc *hp; 257 258 mtx_lock(&hookprocs_lock); 259 hp = hook_find(pid); 260 if (hp == NULL) { 261 mtx_unlock(&hookprocs_lock); 262 pjdlog_debug(1, "Unknown process pid=%u", pid); 263 return; 264 } 265 hook_remove(hp); 266 mtx_unlock(&hookprocs_lock); 267 if (WIFEXITED(status) && WEXITSTATUS(status) == 0) { 268 pjdlog_debug(1, "Hook exited gracefully (pid=%u, cmd=[%s]).", 269 pid, hp->hp_comm); 270 } else if (WIFSIGNALED(status)) { 271 pjdlog_error("Hook was killed (pid=%u, signal=%d, cmd=[%s]).", 272 pid, WTERMSIG(status), hp->hp_comm); 273 } else { 274 pjdlog_error("Hook exited ungracefully (pid=%u, exitcode=%d, cmd=[%s]).", 275 pid, WIFEXITED(status) ? WEXITSTATUS(status) : -1, 276 hp->hp_comm); 277 } 278 hook_free(hp); 279 } 280 281 void 282 hook_check(void) 283 { 284 struct hookproc *hp, *hp2; 285 time_t now; 286 287 PJDLOG_ASSERT(hooks_initialized); 288 289 pjdlog_debug(2, "Checking hooks."); 290 291 /* 292 * Report about processes that are running for a long time. 293 */ 294 now = time(NULL); 295 mtx_lock(&hookprocs_lock); 296 TAILQ_FOREACH_SAFE(hp, &hookprocs, hp_next, hp2) { 297 PJDLOG_ASSERT(hp->hp_magic == HOOKPROC_MAGIC_ONLIST); 298 PJDLOG_ASSERT(hp->hp_pid > 0); 299 300 /* 301 * If process doesn't exists we somehow missed it. 302 * Not much can be done expect for logging this situation. 303 */ 304 if (kill(hp->hp_pid, 0) == -1 && errno == ESRCH) { 305 pjdlog_warning("Hook disappeared (pid=%u, cmd=[%s]).", 306 hp->hp_pid, hp->hp_comm); 307 hook_remove(hp); 308 hook_free(hp); 309 continue; 310 } 311 312 /* 313 * Skip proccesses younger than 1 minute. 314 */ 315 if (now - hp->hp_lastreport < REPORT_INTERVAL) 316 continue; 317 318 /* 319 * Hook is running for too long, report it. 320 */ 321 pjdlog_warning("Hook is running for %ju seconds (pid=%u, cmd=[%s]).", 322 (uintmax_t)(now - hp->hp_birthtime), hp->hp_pid, 323 hp->hp_comm); 324 hp->hp_lastreport = now; 325 } 326 mtx_unlock(&hookprocs_lock); 327 } 328 329 void 330 hook_exec(const char *path, ...) 331 { 332 va_list ap; 333 334 va_start(ap, path); 335 hook_execv(path, ap); 336 va_end(ap); 337 } 338 339 void 340 hook_execv(const char *path, va_list ap) 341 { 342 struct hookproc *hp; 343 char *args[64]; 344 unsigned int ii; 345 sigset_t mask; 346 pid_t pid; 347 348 PJDLOG_ASSERT(hooks_initialized); 349 350 if (path == NULL || path[0] == '\0') 351 return; 352 353 memset(args, 0, sizeof(args)); 354 args[0] = __DECONST(char *, path); 355 for (ii = 1; ii < sizeof(args) / sizeof(args[0]); ii++) { 356 args[ii] = va_arg(ap, char *); 357 if (args[ii] == NULL) 358 break; 359 } 360 PJDLOG_ASSERT(ii < sizeof(args) / sizeof(args[0])); 361 362 hp = hook_alloc(path, args); 363 if (hp == NULL) 364 return; 365 366 pjdlog_debug(1, "Executing hook: %s", hp->hp_comm); 367 368 pid = fork(); 369 switch (pid) { 370 case -1: /* Error. */ 371 pjdlog_errno(LOG_ERR, "Unable to fork to execute %s", path); 372 hook_free(hp); 373 return; 374 case 0: /* Child. */ 375 descriptors(); 376 PJDLOG_VERIFY(sigemptyset(&mask) == 0); 377 PJDLOG_VERIFY(sigprocmask(SIG_SETMASK, &mask, NULL) == 0); 378 /* 379 * Dummy handler set for SIGCHLD in the parent will be restored 380 * to SIG_IGN on execv(3) below, so there is no need to do 381 * anything with it. 382 */ 383 execv(path, args); 384 pjdlog_errno(LOG_ERR, "Unable to execute %s", path); 385 exit(EX_SOFTWARE); 386 default: /* Parent. */ 387 hook_add(hp, pid); 388 break; 389 } 390 } 391