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 /* 87 * Do this instead of log_err() to avoid calling 88 * done() again with error, from atexit handler. 89 */ 90 log_warn("AUTOFSDONE"); 91 } 92 quick_exit(1); 93 } 94 95 /* 96 * Remove "fstype=whatever" from optionsp and return the "whatever" part. 97 */ 98 static char * 99 pick_option(const char *option, char **optionsp) 100 { 101 char *tofree, *pair, *newoptions; 102 char *picked = NULL; 103 bool first = true; 104 105 tofree = *optionsp; 106 107 newoptions = calloc(strlen(*optionsp) + 1, 1); 108 if (newoptions == NULL) 109 log_err(1, "calloc"); 110 111 while ((pair = strsep(optionsp, ",")) != NULL) { 112 /* 113 * XXX: strncasecmp(3) perhaps? 114 */ 115 if (strncmp(pair, option, strlen(option)) == 0) { 116 picked = checked_strdup(pair + strlen(option)); 117 } else { 118 if (first == false) 119 strcat(newoptions, ","); 120 else 121 first = false; 122 strcat(newoptions, pair); 123 } 124 } 125 126 free(tofree); 127 *optionsp = newoptions; 128 129 return (picked); 130 } 131 132 static void 133 create_subtree(const struct node *node, bool incomplete) 134 { 135 const struct node *child; 136 char *path; 137 bool wildcard_found = false; 138 139 /* 140 * Skip wildcard nodes. 141 */ 142 if (strcmp(node->n_key, "*") == 0) 143 return; 144 145 path = node_path(node); 146 log_debugx("creating subtree at %s", path); 147 create_directory(path); 148 149 if (incomplete) { 150 TAILQ_FOREACH(child, &node->n_children, n_next) { 151 if (strcmp(child->n_key, "*") == 0) { 152 wildcard_found = true; 153 break; 154 } 155 } 156 157 if (wildcard_found) { 158 log_debugx("node %s contains wildcard entry; " 159 "not creating its subdirectories due to -d flag", 160 path); 161 free(path); 162 return; 163 } 164 } 165 166 free(path); 167 168 TAILQ_FOREACH(child, &node->n_children, n_next) 169 create_subtree(child, incomplete); 170 } 171 172 static void 173 exit_callback(void) 174 { 175 176 done(EIO, true); 177 } 178 179 static void 180 handle_request(const struct autofs_daemon_request *adr, char *cmdline_options, 181 bool incomplete_hierarchy) 182 { 183 const char *map; 184 struct node *root, *parent, *node; 185 FILE *f; 186 char *options, *fstype, *nobrowse, *retrycnt, *tmp; 187 int error; 188 bool wildcards; 189 190 log_debugx("got request %d: from %s, path %s, prefix \"%s\", " 191 "key \"%s\", options \"%s\"", adr->adr_id, adr->adr_from, 192 adr->adr_path, adr->adr_prefix, adr->adr_key, adr->adr_options); 193 194 /* 195 * Try to notify the kernel about any problems. 196 */ 197 request_id = adr->adr_id; 198 atexit(exit_callback); 199 200 if (strncmp(adr->adr_from, "map ", 4) != 0) { 201 log_errx(1, "invalid mountfrom \"%s\"; failing request", 202 adr->adr_from); 203 } 204 205 map = adr->adr_from + 4; /* 4 for strlen("map "); */ 206 root = node_new_root(); 207 if (adr->adr_prefix[0] == '\0' || strcmp(adr->adr_prefix, "/") == 0) { 208 parent = root; 209 } else { 210 parent = node_new_map(root, checked_strdup(adr->adr_prefix), 211 checked_strdup(adr->adr_options), checked_strdup(map), 212 checked_strdup("[kernel request]"), lineno); 213 } 214 215 /* 216 * "Wildcards" here actually means "make autofs(4) request 217 * automountd(8) action if the node being looked up does not 218 * exist, even though the parent is marked as cached". This 219 * needs to be done for maps with wildcard entries, but also 220 * for special and executable maps. 221 */ 222 parse_map(parent, map, adr->adr_key[0] != '\0' ? adr->adr_key : NULL, 223 &wildcards); 224 if (!wildcards) 225 wildcards = node_has_wildcards(parent); 226 if (wildcards) 227 log_debugx("map may contain wildcard entries"); 228 else 229 log_debugx("map does not contain wildcard entries"); 230 231 if (adr->adr_key[0] != '\0') 232 node_expand_wildcard(root, adr->adr_key); 233 234 node = node_find(root, adr->adr_path); 235 if (node == NULL) { 236 log_errx(1, "map %s does not contain key for \"%s\"; " 237 "failing mount", map, adr->adr_path); 238 } 239 240 if (node->n_location == NULL) { 241 log_debugx("found node defined at %s:%d; not a mountpoint", 242 node->n_config_file, node->n_config_line); 243 244 options = node_options(node); 245 246 /* 247 * Prepend options passed via automountd(8) command line. 248 */ 249 if (cmdline_options != NULL) { 250 options = 251 separated_concat(cmdline_options, options, ','); 252 } 253 254 nobrowse = pick_option("nobrowse", &options); 255 if (nobrowse != NULL && adr->adr_key[0] == '\0') { 256 log_debugx("skipping map %s due to \"nobrowse\" " 257 "option; exiting", map); 258 done(0, true); 259 260 /* 261 * Exit without calling exit_callback(). 262 */ 263 quick_exit(0); 264 } 265 266 /* 267 * Not a mountpoint; create directories in the autofs mount 268 * and complete the request. 269 */ 270 create_subtree(node, incomplete_hierarchy); 271 272 if (incomplete_hierarchy && adr->adr_key[0] != '\0') { 273 /* 274 * We still need to create the single subdirectory 275 * user is trying to access. 276 */ 277 tmp = separated_concat(adr->adr_path, 278 adr->adr_key, '/'); 279 node = node_find(root, tmp); 280 if (node != NULL) 281 create_subtree(node, false); 282 } 283 284 log_debugx("nothing to mount; exiting"); 285 done(0, wildcards); 286 287 /* 288 * Exit without calling exit_callback(). 289 */ 290 quick_exit(0); 291 } 292 293 log_debugx("found node defined at %s:%d; it is a mountpoint", 294 node->n_config_file, node->n_config_line); 295 296 node_expand_ampersand(node, 297 adr->adr_key[0] != '\0' ? adr->adr_key : NULL); 298 error = node_expand_defined(node); 299 if (error != 0) { 300 log_errx(1, "variable expansion failed for %s; " 301 "failing mount", adr->adr_path); 302 } 303 304 options = node_options(node); 305 306 /* 307 * Prepend options passed via automountd(8) command line. 308 */ 309 if (cmdline_options != NULL) 310 options = separated_concat(cmdline_options, options, ','); 311 312 /* 313 * Append "automounted". 314 */ 315 options = separated_concat(options, "automounted", ','); 316 317 /* 318 * Remove "nobrowse", mount(8) doesn't understand it. 319 */ 320 pick_option("nobrowse", &options); 321 322 /* 323 * Figure out fstype. 324 */ 325 fstype = pick_option("fstype=", &options); 326 if (fstype == NULL) { 327 log_debugx("fstype not specified in options; " 328 "defaulting to \"nfs\""); 329 fstype = checked_strdup("nfs"); 330 } 331 332 if (strcmp(fstype, "nfs") == 0) { 333 /* 334 * The mount_nfs(8) command defaults to retry undefinitely. 335 * We do not want that behaviour, because it leaves mount_nfs(8) 336 * instances and automountd(8) children hanging forever. 337 * Disable retries unless the option was passed explicitly. 338 */ 339 retrycnt = pick_option("retrycnt=", &options); 340 if (retrycnt == NULL) { 341 log_debugx("retrycnt not specified in options; " 342 "defaulting to 1"); 343 options = separated_concat(options, 344 separated_concat("retrycnt", "1", '='), ','); 345 } else { 346 options = separated_concat(options, 347 separated_concat("retrycnt", retrycnt, '='), ','); 348 } 349 } 350 351 f = auto_popen("mount", "-t", fstype, "-o", options, 352 node->n_location, adr->adr_path, NULL); 353 assert(f != NULL); 354 error = auto_pclose(f); 355 if (error != 0) 356 log_errx(1, "mount failed"); 357 358 log_debugx("mount done; exiting"); 359 done(0, wildcards); 360 361 /* 362 * Exit without calling exit_callback(). 363 */ 364 quick_exit(0); 365 } 366 367 static void 368 sigchld_handler(int dummy __unused) 369 { 370 371 /* 372 * The only purpose of this handler is to make SIGCHLD 373 * interrupt the AUTOFSREQUEST ioctl(2), so we can call 374 * wait_for_children(). 375 */ 376 } 377 378 static void 379 register_sigchld(void) 380 { 381 struct sigaction sa; 382 int error; 383 384 bzero(&sa, sizeof(sa)); 385 sa.sa_handler = sigchld_handler; 386 sigfillset(&sa.sa_mask); 387 error = sigaction(SIGCHLD, &sa, NULL); 388 if (error != 0) 389 log_err(1, "sigaction"); 390 391 } 392 393 394 static int 395 wait_for_children(bool block) 396 { 397 pid_t pid; 398 int status; 399 int num = 0; 400 401 for (;;) { 402 /* 403 * If "block" is true, wait for at least one process. 404 */ 405 if (block && num == 0) 406 pid = wait4(-1, &status, 0, NULL); 407 else 408 pid = wait4(-1, &status, WNOHANG, NULL); 409 if (pid <= 0) 410 break; 411 if (WIFSIGNALED(status)) { 412 log_warnx("child process %d terminated with signal %d", 413 pid, WTERMSIG(status)); 414 } else if (WEXITSTATUS(status) != 0) { 415 log_debugx("child process %d terminated with exit status %d", 416 pid, WEXITSTATUS(status)); 417 } else { 418 log_debugx("child process %d terminated gracefully", pid); 419 } 420 num++; 421 } 422 423 return (num); 424 } 425 426 static void 427 usage_automountd(void) 428 { 429 430 fprintf(stderr, "usage: automountd [-D name=value][-m maxproc]" 431 "[-o opts][-Tidv]\n"); 432 exit(1); 433 } 434 435 int 436 main_automountd(int argc, char **argv) 437 { 438 struct pidfh *pidfh; 439 pid_t pid, otherpid; 440 const char *pidfile_path = AUTOMOUNTD_PIDFILE; 441 char *options = NULL; 442 struct autofs_daemon_request request; 443 int ch, debug = 0, error, maxproc = 30, retval, saved_errno; 444 bool dont_daemonize = false, incomplete_hierarchy = false; 445 446 defined_init(); 447 448 while ((ch = getopt(argc, argv, "D:Tdim:o:v")) != -1) { 449 switch (ch) { 450 case 'D': 451 defined_parse_and_add(optarg); 452 break; 453 case 'T': 454 /* 455 * For compatibility with other implementations, 456 * such as OS X. 457 */ 458 debug++; 459 break; 460 case 'd': 461 dont_daemonize = true; 462 debug++; 463 break; 464 case 'i': 465 incomplete_hierarchy = true; 466 break; 467 case 'm': 468 maxproc = atoi(optarg); 469 break; 470 case 'o': 471 if (options == NULL) { 472 options = checked_strdup(optarg); 473 } else { 474 options = 475 separated_concat(options, optarg, ','); 476 } 477 break; 478 case 'v': 479 debug++; 480 break; 481 case '?': 482 default: 483 usage_automountd(); 484 } 485 } 486 argc -= optind; 487 if (argc != 0) 488 usage_automountd(); 489 490 log_init(debug); 491 492 pidfh = pidfile_open(pidfile_path, 0600, &otherpid); 493 if (pidfh == NULL) { 494 if (errno == EEXIST) { 495 log_errx(1, "daemon already running, pid: %jd.", 496 (intmax_t)otherpid); 497 } 498 log_err(1, "cannot open or create pidfile \"%s\"", 499 pidfile_path); 500 } 501 502 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 503 if (autofs_fd < 0 && errno == ENOENT) { 504 saved_errno = errno; 505 retval = kldload("autofs"); 506 if (retval != -1) 507 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 508 else 509 errno = saved_errno; 510 } 511 if (autofs_fd < 0) 512 log_err(1, "failed to open %s", AUTOFS_PATH); 513 514 if (dont_daemonize == false) { 515 if (daemon(0, 0) == -1) { 516 log_warn("cannot daemonize"); 517 pidfile_remove(pidfh); 518 exit(1); 519 } 520 } else { 521 lesser_daemon(); 522 } 523 524 pidfile_write(pidfh); 525 526 register_sigchld(); 527 528 for (;;) { 529 log_debugx("waiting for request from the kernel"); 530 531 memset(&request, 0, sizeof(request)); 532 error = ioctl(autofs_fd, AUTOFSREQUEST, &request); 533 if (error != 0) { 534 if (errno == EINTR) { 535 nchildren -= wait_for_children(false); 536 assert(nchildren >= 0); 537 continue; 538 } 539 540 log_err(1, "AUTOFSREQUEST"); 541 } 542 543 if (dont_daemonize) { 544 log_debugx("not forking due to -d flag; " 545 "will exit after servicing a single request"); 546 } else { 547 nchildren -= wait_for_children(false); 548 assert(nchildren >= 0); 549 550 while (maxproc > 0 && nchildren >= maxproc) { 551 log_debugx("maxproc limit of %d child processes hit; " 552 "waiting for child process to exit", maxproc); 553 nchildren -= wait_for_children(true); 554 assert(nchildren >= 0); 555 } 556 log_debugx("got request; forking child process #%d", 557 nchildren); 558 nchildren++; 559 560 pid = fork(); 561 if (pid < 0) 562 log_err(1, "fork"); 563 if (pid > 0) 564 continue; 565 } 566 567 pidfile_close(pidfh); 568 handle_request(&request, options, incomplete_hierarchy); 569 } 570 571 pidfile_close(pidfh); 572 573 return (0); 574 } 575 576