1 /*- 2 * Copyright (c) 2014 The FreeBSD Foundation 3 * All rights reserved. 4 * 5 * This software was developed by Edward Tomasz Napierala under sponsorship 6 * from the FreeBSD Foundation. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 */ 30 31 #include <sys/cdefs.h> 32 __FBSDID("$FreeBSD$"); 33 34 #include <sys/types.h> 35 #include <sys/time.h> 36 #include <sys/ioctl.h> 37 #include <sys/param.h> 38 #include <sys/linker.h> 39 #include <sys/mount.h> 40 #include <sys/socket.h> 41 #include <sys/stat.h> 42 #include <sys/wait.h> 43 #include <sys/utsname.h> 44 #include <assert.h> 45 #include <ctype.h> 46 #include <errno.h> 47 #include <fcntl.h> 48 #include <libgen.h> 49 #include <netdb.h> 50 #include <signal.h> 51 #include <stdbool.h> 52 #include <stdint.h> 53 #include <stdio.h> 54 #include <stdlib.h> 55 #include <string.h> 56 #include <unistd.h> 57 58 #include <libutil.h> 59 60 #include "autofs_ioctl.h" 61 62 #include "common.h" 63 64 #define AUTOMOUNTD_PIDFILE "/var/run/automountd.pid" 65 66 static int nchildren = 0; 67 static int autofs_fd; 68 static int request_id; 69 70 static void 71 done(int request_error, bool wildcards) 72 { 73 struct autofs_daemon_done add; 74 int error; 75 76 memset(&add, 0, sizeof(add)); 77 add.add_id = request_id; 78 add.add_wildcards = wildcards; 79 add.add_error = request_error; 80 81 log_debugx("completing request %d with error %d", 82 request_id, request_error); 83 84 error = ioctl(autofs_fd, AUTOFSDONE, &add); 85 if (error != 0) 86 log_warn("AUTOFSDONE"); 87 } 88 89 /* 90 * Remove "fstype=whatever" from optionsp and return the "whatever" part. 91 */ 92 static char * 93 pick_option(const char *option, char **optionsp) 94 { 95 char *tofree, *pair, *newoptions; 96 char *picked = NULL; 97 bool first = true; 98 99 tofree = *optionsp; 100 101 newoptions = calloc(strlen(*optionsp) + 1, 1); 102 if (newoptions == NULL) 103 log_err(1, "calloc"); 104 105 while ((pair = strsep(optionsp, ",")) != NULL) { 106 /* 107 * XXX: strncasecmp(3) perhaps? 108 */ 109 if (strncmp(pair, option, strlen(option)) == 0) { 110 picked = checked_strdup(pair + strlen(option)); 111 } else { 112 if (first == false) 113 strcat(newoptions, ","); 114 else 115 first = false; 116 strcat(newoptions, pair); 117 } 118 } 119 120 free(tofree); 121 *optionsp = newoptions; 122 123 return (picked); 124 } 125 126 static void 127 create_subtree(const struct node *node, bool incomplete) 128 { 129 const struct node *child; 130 char *path; 131 bool wildcard_found = false; 132 133 /* 134 * Skip wildcard nodes. 135 */ 136 if (strcmp(node->n_key, "*") == 0) 137 return; 138 139 path = node_path(node); 140 log_debugx("creating subtree at %s", path); 141 create_directory(path); 142 143 if (incomplete) { 144 TAILQ_FOREACH(child, &node->n_children, n_next) { 145 if (strcmp(child->n_key, "*") == 0) { 146 wildcard_found = true; 147 break; 148 } 149 } 150 151 if (wildcard_found) { 152 log_debugx("node %s contains wildcard entry; " 153 "not creating its subdirectories due to -d flag", 154 path); 155 free(path); 156 return; 157 } 158 } 159 160 free(path); 161 162 TAILQ_FOREACH(child, &node->n_children, n_next) 163 create_subtree(child, incomplete); 164 } 165 166 static void 167 exit_callback(void) 168 { 169 170 done(EIO, true); 171 } 172 173 static void 174 handle_request(const struct autofs_daemon_request *adr, char *cmdline_options, 175 bool incomplete_hierarchy) 176 { 177 const char *map; 178 struct node *root, *parent, *node; 179 FILE *f; 180 char *options, *fstype, *nobrowse, *retrycnt, *tmp; 181 int error; 182 bool wildcards; 183 184 log_debugx("got request %d: from %s, path %s, prefix \"%s\", " 185 "key \"%s\", options \"%s\"", adr->adr_id, adr->adr_from, 186 adr->adr_path, adr->adr_prefix, adr->adr_key, adr->adr_options); 187 188 /* 189 * Try to notify the kernel about any problems. 190 */ 191 request_id = adr->adr_id; 192 atexit(exit_callback); 193 194 if (strncmp(adr->adr_from, "map ", 4) != 0) { 195 log_errx(1, "invalid mountfrom \"%s\"; failing request", 196 adr->adr_from); 197 } 198 199 map = adr->adr_from + 4; /* 4 for strlen("map "); */ 200 root = node_new_root(); 201 if (adr->adr_prefix[0] == '\0' || strcmp(adr->adr_prefix, "/") == 0) { 202 parent = root; 203 } else { 204 parent = node_new_map(root, checked_strdup(adr->adr_prefix), 205 checked_strdup(adr->adr_options), checked_strdup(map), 206 checked_strdup("[kernel request]"), lineno); 207 } 208 209 /* 210 * "Wildcards" here actually means "make autofs(4) request 211 * automountd(8) action if the node being looked up does not 212 * exist, even though the parent is marked as cached". This 213 * needs to be done for maps with wildcard entries, but also 214 * for special and executable maps. 215 */ 216 parse_map(parent, map, adr->adr_key[0] != '\0' ? adr->adr_key : NULL, 217 &wildcards); 218 if (!wildcards) 219 wildcards = node_has_wildcards(parent); 220 if (wildcards) 221 log_debugx("map may contain wildcard entries"); 222 else 223 log_debugx("map does not contain wildcard entries"); 224 225 if (adr->adr_key[0] != '\0') 226 node_expand_wildcard(root, adr->adr_key); 227 228 node = node_find(root, adr->adr_path); 229 if (node == NULL) { 230 log_errx(1, "map %s does not contain key for \"%s\"; " 231 "failing mount", map, adr->adr_path); 232 } 233 234 if (node->n_location == NULL) { 235 log_debugx("found node defined at %s:%d; not a mountpoint", 236 node->n_config_file, node->n_config_line); 237 238 options = node_options(node); 239 240 /* 241 * Prepend options passed via automountd(8) command line. 242 */ 243 if (cmdline_options != NULL) { 244 options = 245 separated_concat(cmdline_options, options, ','); 246 } 247 248 nobrowse = pick_option("nobrowse", &options); 249 if (nobrowse != NULL && adr->adr_key[0] == '\0') { 250 log_debugx("skipping map %s due to \"nobrowse\" " 251 "option; exiting", map); 252 done(0, true); 253 254 /* 255 * Exit without calling exit_callback(). 256 */ 257 quick_exit(0); 258 } 259 260 /* 261 * Not a mountpoint; create directories in the autofs mount 262 * and complete the request. 263 */ 264 create_subtree(node, incomplete_hierarchy); 265 266 if (incomplete_hierarchy && adr->adr_key[0] != '\0') { 267 /* 268 * We still need to create the single subdirectory 269 * user is trying to access. 270 */ 271 tmp = separated_concat(adr->adr_path, 272 adr->adr_key, '/'); 273 node = node_find(root, tmp); 274 if (node != NULL) 275 create_subtree(node, false); 276 } 277 278 log_debugx("nothing to mount; exiting"); 279 done(0, wildcards); 280 281 /* 282 * Exit without calling exit_callback(). 283 */ 284 quick_exit(0); 285 } 286 287 log_debugx("found node defined at %s:%d; it is a mountpoint", 288 node->n_config_file, node->n_config_line); 289 290 node_expand_ampersand(node, 291 adr->adr_key[0] != '\0' ? adr->adr_key : NULL); 292 error = node_expand_defined(node); 293 if (error != 0) { 294 log_errx(1, "variable expansion failed for %s; " 295 "failing mount", adr->adr_path); 296 } 297 298 options = node_options(node); 299 300 /* 301 * Prepend options passed via automountd(8) command line. 302 */ 303 if (cmdline_options != NULL) 304 options = separated_concat(cmdline_options, options, ','); 305 306 /* 307 * Append "automounted". 308 */ 309 options = separated_concat(options, "automounted", ','); 310 311 /* 312 * Remove "nobrowse", mount(8) doesn't understand it. 313 */ 314 pick_option("nobrowse", &options); 315 316 /* 317 * Figure out fstype. 318 */ 319 fstype = pick_option("fstype=", &options); 320 if (fstype == NULL) { 321 log_debugx("fstype not specified in options; " 322 "defaulting to \"nfs\""); 323 fstype = checked_strdup("nfs"); 324 } 325 326 if (strcmp(fstype, "nfs") == 0) { 327 /* 328 * The mount_nfs(8) command defaults to retry undefinitely. 329 * We do not want that behaviour, because it leaves mount_nfs(8) 330 * instances and automountd(8) children hanging forever. 331 * Disable retries unless the option was passed explicitly. 332 */ 333 retrycnt = pick_option("retrycnt=", &options); 334 if (retrycnt == NULL) { 335 log_debugx("retrycnt not specified in options; " 336 "defaulting to 1"); 337 options = separated_concat(options, 338 separated_concat("retrycnt", "1", '='), ','); 339 } else { 340 options = separated_concat(options, 341 separated_concat("retrycnt", retrycnt, '='), ','); 342 } 343 } 344 345 f = auto_popen("mount", "-t", fstype, "-o", options, 346 node->n_location, adr->adr_path, NULL); 347 assert(f != NULL); 348 error = auto_pclose(f); 349 if (error != 0) 350 log_errx(1, "mount failed"); 351 352 log_debugx("mount done; exiting"); 353 done(0, wildcards); 354 355 /* 356 * Exit without calling exit_callback(). 357 */ 358 quick_exit(0); 359 } 360 361 static void 362 sigchld_handler(int dummy __unused) 363 { 364 365 /* 366 * The only purpose of this handler is to make SIGCHLD 367 * interrupt the AUTOFSREQUEST ioctl(2), so we can call 368 * wait_for_children(). 369 */ 370 } 371 372 static void 373 register_sigchld(void) 374 { 375 struct sigaction sa; 376 int error; 377 378 bzero(&sa, sizeof(sa)); 379 sa.sa_handler = sigchld_handler; 380 sigfillset(&sa.sa_mask); 381 error = sigaction(SIGCHLD, &sa, NULL); 382 if (error != 0) 383 log_err(1, "sigaction"); 384 385 } 386 387 388 static int 389 wait_for_children(bool block) 390 { 391 pid_t pid; 392 int status; 393 int num = 0; 394 395 for (;;) { 396 /* 397 * If "block" is true, wait for at least one process. 398 */ 399 if (block && num == 0) 400 pid = wait4(-1, &status, 0, NULL); 401 else 402 pid = wait4(-1, &status, WNOHANG, NULL); 403 if (pid <= 0) 404 break; 405 if (WIFSIGNALED(status)) { 406 log_warnx("child process %d terminated with signal %d", 407 pid, WTERMSIG(status)); 408 } else if (WEXITSTATUS(status) != 0) { 409 log_debugx("child process %d terminated with exit status %d", 410 pid, WEXITSTATUS(status)); 411 } else { 412 log_debugx("child process %d terminated gracefully", pid); 413 } 414 num++; 415 } 416 417 return (num); 418 } 419 420 static void 421 usage_automountd(void) 422 { 423 424 fprintf(stderr, "usage: automountd [-D name=value][-m maxproc]" 425 "[-o opts][-Tidv]\n"); 426 exit(1); 427 } 428 429 int 430 main_automountd(int argc, char **argv) 431 { 432 struct pidfh *pidfh; 433 pid_t pid, otherpid; 434 const char *pidfile_path = AUTOMOUNTD_PIDFILE; 435 char *options = NULL; 436 struct autofs_daemon_request request; 437 int ch, debug = 0, error, maxproc = 30, retval, saved_errno; 438 bool dont_daemonize = false, incomplete_hierarchy = false; 439 440 defined_init(); 441 442 while ((ch = getopt(argc, argv, "D:Tdim:o:v")) != -1) { 443 switch (ch) { 444 case 'D': 445 defined_parse_and_add(optarg); 446 break; 447 case 'T': 448 /* 449 * For compatibility with other implementations, 450 * such as OS X. 451 */ 452 debug++; 453 break; 454 case 'd': 455 dont_daemonize = true; 456 debug++; 457 break; 458 case 'i': 459 incomplete_hierarchy = true; 460 break; 461 case 'm': 462 maxproc = atoi(optarg); 463 break; 464 case 'o': 465 if (options == NULL) { 466 options = checked_strdup(optarg); 467 } else { 468 options = 469 separated_concat(options, optarg, ','); 470 } 471 break; 472 case 'v': 473 debug++; 474 break; 475 case '?': 476 default: 477 usage_automountd(); 478 } 479 } 480 argc -= optind; 481 if (argc != 0) 482 usage_automountd(); 483 484 log_init(debug); 485 486 pidfh = pidfile_open(pidfile_path, 0600, &otherpid); 487 if (pidfh == NULL) { 488 if (errno == EEXIST) { 489 log_errx(1, "daemon already running, pid: %jd.", 490 (intmax_t)otherpid); 491 } 492 log_err(1, "cannot open or create pidfile \"%s\"", 493 pidfile_path); 494 } 495 496 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 497 if (autofs_fd < 0 && errno == ENOENT) { 498 saved_errno = errno; 499 retval = kldload("autofs"); 500 if (retval != -1) 501 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 502 else 503 errno = saved_errno; 504 } 505 if (autofs_fd < 0) 506 log_err(1, "failed to open %s", AUTOFS_PATH); 507 508 if (dont_daemonize == false) { 509 if (daemon(0, 0) == -1) { 510 log_warn("cannot daemonize"); 511 pidfile_remove(pidfh); 512 exit(1); 513 } 514 } else { 515 lesser_daemon(); 516 } 517 518 pidfile_write(pidfh); 519 520 register_sigchld(); 521 522 for (;;) { 523 log_debugx("waiting for request from the kernel"); 524 525 memset(&request, 0, sizeof(request)); 526 error = ioctl(autofs_fd, AUTOFSREQUEST, &request); 527 if (error != 0) { 528 if (errno == EINTR) { 529 nchildren -= wait_for_children(false); 530 assert(nchildren >= 0); 531 continue; 532 } 533 534 log_err(1, "AUTOFSREQUEST"); 535 } 536 537 if (dont_daemonize) { 538 log_debugx("not forking due to -d flag; " 539 "will exit after servicing a single request"); 540 } else { 541 nchildren -= wait_for_children(false); 542 assert(nchildren >= 0); 543 544 while (maxproc > 0 && nchildren >= maxproc) { 545 log_debugx("maxproc limit of %d child processes hit; " 546 "waiting for child process to exit", maxproc); 547 nchildren -= wait_for_children(true); 548 assert(nchildren >= 0); 549 } 550 log_debugx("got request; forking child process #%d", 551 nchildren); 552 nchildren++; 553 554 pid = fork(); 555 if (pid < 0) 556 log_err(1, "fork"); 557 if (pid > 0) 558 continue; 559 } 560 561 pidfile_close(pidfh); 562 handle_request(&request, options, incomplete_hierarchy); 563 } 564 565 pidfile_close(pidfh); 566 567 return (0); 568 } 569 570