1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2014 The FreeBSD Foundation 5 * All rights reserved. 6 * 7 * This software was developed by Edward Tomasz Napierala under sponsorship 8 * from the FreeBSD Foundation. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 20 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 22 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 23 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 24 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 25 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 26 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 27 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 28 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 29 * SUCH DAMAGE. 30 * 31 */ 32 33 #include <sys/cdefs.h> 34 __FBSDID("$FreeBSD$"); 35 36 #include <sys/types.h> 37 #include <sys/time.h> 38 #include <sys/ioctl.h> 39 #include <sys/param.h> 40 #include <sys/linker.h> 41 #include <sys/mount.h> 42 #include <sys/socket.h> 43 #include <sys/stat.h> 44 #include <sys/wait.h> 45 #include <sys/utsname.h> 46 #include <assert.h> 47 #include <ctype.h> 48 #include <errno.h> 49 #include <fcntl.h> 50 #include <libgen.h> 51 #include <libutil.h> 52 #include <netdb.h> 53 #include <signal.h> 54 #include <stdbool.h> 55 #include <stdint.h> 56 #include <stdio.h> 57 #include <stdlib.h> 58 #include <string.h> 59 #include <unistd.h> 60 61 #include "autofs_ioctl.h" 62 63 #include "common.h" 64 65 #define AUTOMOUNTD_PIDFILE "/var/run/automountd.pid" 66 67 static int nchildren = 0; 68 static int autofs_fd; 69 static int request_id; 70 71 static void 72 done(int request_error, bool wildcards) 73 { 74 struct autofs_daemon_done add; 75 int error; 76 77 memset(&add, 0, sizeof(add)); 78 add.add_id = request_id; 79 add.add_wildcards = wildcards; 80 add.add_error = request_error; 81 82 log_debugx("completing request %d with error %d", 83 request_id, request_error); 84 85 error = ioctl(autofs_fd, AUTOFSDONE, &add); 86 if (error != 0) 87 log_warn("AUTOFSDONE"); 88 } 89 90 /* 91 * Remove "fstype=whatever" from optionsp and return the "whatever" part. 92 */ 93 static char * 94 pick_option(const char *option, char **optionsp) 95 { 96 char *tofree, *pair, *newoptions; 97 char *picked = NULL; 98 bool first = true; 99 100 tofree = *optionsp; 101 102 newoptions = calloc(1, strlen(*optionsp) + 1); 103 if (newoptions == NULL) 104 log_err(1, "calloc"); 105 106 while ((pair = strsep(optionsp, ",")) != NULL) { 107 /* 108 * XXX: strncasecmp(3) perhaps? 109 */ 110 if (strncmp(pair, option, strlen(option)) == 0) { 111 picked = checked_strdup(pair + strlen(option)); 112 } else { 113 if (first == false) 114 strcat(newoptions, ","); 115 else 116 first = false; 117 strcat(newoptions, pair); 118 } 119 } 120 121 free(tofree); 122 *optionsp = newoptions; 123 124 return (picked); 125 } 126 127 static void 128 create_subtree(const struct node *node, bool incomplete) 129 { 130 const struct node *child; 131 char *path; 132 bool wildcard_found = false; 133 134 /* 135 * Skip wildcard nodes. 136 */ 137 if (strcmp(node->n_key, "*") == 0) 138 return; 139 140 path = node_path(node); 141 log_debugx("creating subtree at %s", path); 142 create_directory(path); 143 144 if (incomplete) { 145 TAILQ_FOREACH(child, &node->n_children, n_next) { 146 if (strcmp(child->n_key, "*") == 0) { 147 wildcard_found = true; 148 break; 149 } 150 } 151 152 if (wildcard_found) { 153 log_debugx("node %s contains wildcard entry; " 154 "not creating its subdirectories due to -d flag", 155 path); 156 free(path); 157 return; 158 } 159 } 160 161 free(path); 162 163 TAILQ_FOREACH(child, &node->n_children, n_next) 164 create_subtree(child, incomplete); 165 } 166 167 static void 168 exit_callback(void) 169 { 170 171 done(EIO, true); 172 } 173 174 static void 175 handle_request(const struct autofs_daemon_request *adr, char *cmdline_options, 176 bool incomplete_hierarchy) 177 { 178 const char *map; 179 struct node *root, *parent, *node; 180 FILE *f; 181 char *key, *options, *fstype, *nobrowse, *retrycnt, *tmp; 182 int error; 183 bool wildcards; 184 185 log_debugx("got request %d: from %s, path %s, prefix \"%s\", " 186 "key \"%s\", options \"%s\"", adr->adr_id, adr->adr_from, 187 adr->adr_path, adr->adr_prefix, adr->adr_key, adr->adr_options); 188 189 /* 190 * Try to notify the kernel about any problems. 191 */ 192 request_id = adr->adr_id; 193 atexit(exit_callback); 194 195 if (strncmp(adr->adr_from, "map ", 4) != 0) { 196 log_errx(1, "invalid mountfrom \"%s\"; failing request", 197 adr->adr_from); 198 } 199 200 map = adr->adr_from + 4; /* 4 for strlen("map "); */ 201 root = node_new_root(); 202 if (adr->adr_prefix[0] == '\0' || strcmp(adr->adr_prefix, "/") == 0) { 203 /* 204 * Direct map. autofs(4) doesn't have a way to determine 205 * correct map key, but since it's a direct map, we can just 206 * use adr_path instead. 207 */ 208 parent = root; 209 key = checked_strdup(adr->adr_path); 210 } else { 211 /* 212 * Indirect map. 213 */ 214 parent = node_new_map(root, checked_strdup(adr->adr_prefix), 215 NULL, checked_strdup(map), 216 checked_strdup("[kernel request]"), lineno); 217 218 if (adr->adr_key[0] == '\0') 219 key = NULL; 220 else 221 key = checked_strdup(adr->adr_key); 222 } 223 224 /* 225 * "Wildcards" here actually means "make autofs(4) request 226 * automountd(8) action if the node being looked up does not 227 * exist, even though the parent is marked as cached". This 228 * needs to be done for maps with wildcard entries, but also 229 * for special and executable maps. 230 */ 231 parse_map(parent, map, key, &wildcards); 232 if (!wildcards) 233 wildcards = node_has_wildcards(parent); 234 if (wildcards) 235 log_debugx("map may contain wildcard entries"); 236 else 237 log_debugx("map does not contain wildcard entries"); 238 239 if (key != NULL) 240 node_expand_wildcard(root, key); 241 242 node = node_find(root, adr->adr_path); 243 if (node == NULL) { 244 log_errx(1, "map %s does not contain key for \"%s\"; " 245 "failing mount", map, adr->adr_path); 246 } 247 248 options = node_options(node); 249 250 /* 251 * Append options from auto_master. 252 */ 253 options = concat(options, ',', adr->adr_options); 254 255 /* 256 * Prepend options passed via automountd(8) command line. 257 */ 258 options = concat(cmdline_options, ',', options); 259 260 if (node->n_location == NULL) { 261 log_debugx("found node defined at %s:%d; not a mountpoint", 262 node->n_config_file, node->n_config_line); 263 264 nobrowse = pick_option("nobrowse", &options); 265 if (nobrowse != NULL && key == NULL) { 266 log_debugx("skipping map %s due to \"nobrowse\" " 267 "option; exiting", map); 268 done(0, true); 269 270 /* 271 * Exit without calling exit_callback(). 272 */ 273 quick_exit(0); 274 } 275 276 /* 277 * Not a mountpoint; create directories in the autofs mount 278 * and complete the request. 279 */ 280 create_subtree(node, incomplete_hierarchy); 281 282 if (incomplete_hierarchy && key != NULL) { 283 /* 284 * We still need to create the single subdirectory 285 * user is trying to access. 286 */ 287 tmp = concat(adr->adr_path, '/', key); 288 node = node_find(root, tmp); 289 if (node != NULL) 290 create_subtree(node, false); 291 } 292 293 log_debugx("nothing to mount; exiting"); 294 done(0, wildcards); 295 296 /* 297 * Exit without calling exit_callback(). 298 */ 299 quick_exit(0); 300 } 301 302 log_debugx("found node defined at %s:%d; it is a mountpoint", 303 node->n_config_file, node->n_config_line); 304 305 if (key != NULL) 306 node_expand_ampersand(node, key); 307 error = node_expand_defined(node); 308 if (error != 0) { 309 log_errx(1, "variable expansion failed for %s; " 310 "failing mount", adr->adr_path); 311 } 312 313 /* 314 * Append "automounted". 315 */ 316 options = concat(options, ',', "automounted"); 317 318 /* 319 * Remove "nobrowse", mount(8) doesn't understand it. 320 */ 321 pick_option("nobrowse", &options); 322 323 /* 324 * Figure out fstype. 325 */ 326 fstype = pick_option("fstype=", &options); 327 if (fstype == NULL) { 328 log_debugx("fstype not specified in options; " 329 "defaulting to \"nfs\""); 330 fstype = checked_strdup("nfs"); 331 } 332 333 if (strcmp(fstype, "nfs") == 0) { 334 /* 335 * The mount_nfs(8) command defaults to retry undefinitely. 336 * We do not want that behaviour, because it leaves mount_nfs(8) 337 * instances and automountd(8) children hanging forever. 338 * Disable retries unless the option was passed explicitly. 339 */ 340 retrycnt = pick_option("retrycnt=", &options); 341 if (retrycnt == NULL) { 342 log_debugx("retrycnt not specified in options; " 343 "defaulting to 1"); 344 options = concat(options, ',', "retrycnt=1"); 345 } else { 346 options = concat(options, ',', 347 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 options = concat(options, ',', optarg); 472 break; 473 case 'v': 474 debug++; 475 break; 476 case '?': 477 default: 478 usage_automountd(); 479 } 480 } 481 argc -= optind; 482 if (argc != 0) 483 usage_automountd(); 484 485 log_init(debug); 486 487 pidfh = pidfile_open(pidfile_path, 0600, &otherpid); 488 if (pidfh == NULL) { 489 if (errno == EEXIST) { 490 log_errx(1, "daemon already running, pid: %jd.", 491 (intmax_t)otherpid); 492 } 493 log_err(1, "cannot open or create pidfile \"%s\"", 494 pidfile_path); 495 } 496 497 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 498 if (autofs_fd < 0 && errno == ENOENT) { 499 saved_errno = errno; 500 retval = kldload("autofs"); 501 if (retval != -1) 502 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 503 else 504 errno = saved_errno; 505 } 506 if (autofs_fd < 0) 507 log_err(1, "failed to open %s", AUTOFS_PATH); 508 509 if (dont_daemonize == false) { 510 if (daemon(0, 0) == -1) { 511 log_warn("cannot daemonize"); 512 pidfile_remove(pidfh); 513 exit(1); 514 } 515 } else { 516 lesser_daemon(); 517 } 518 519 pidfile_write(pidfh); 520 521 register_sigchld(); 522 523 for (;;) { 524 log_debugx("waiting for request from the kernel"); 525 526 memset(&request, 0, sizeof(request)); 527 error = ioctl(autofs_fd, AUTOFSREQUEST, &request); 528 if (error != 0) { 529 if (errno == EINTR) { 530 nchildren -= wait_for_children(false); 531 assert(nchildren >= 0); 532 continue; 533 } 534 535 log_err(1, "AUTOFSREQUEST"); 536 } 537 538 if (dont_daemonize) { 539 log_debugx("not forking due to -d flag; " 540 "will exit after servicing a single request"); 541 } else { 542 nchildren -= wait_for_children(false); 543 assert(nchildren >= 0); 544 545 while (maxproc > 0 && nchildren >= maxproc) { 546 log_debugx("maxproc limit of %d child processes hit; " 547 "waiting for child process to exit", maxproc); 548 nchildren -= wait_for_children(true); 549 assert(nchildren >= 0); 550 } 551 log_debugx("got request; forking child process #%d", 552 nchildren); 553 nchildren++; 554 555 pid = fork(); 556 if (pid < 0) 557 log_err(1, "fork"); 558 if (pid > 0) 559 continue; 560 } 561 562 pidfile_close(pidfh); 563 handle_request(&request, options, incomplete_hierarchy); 564 } 565 566 pidfile_close(pidfh); 567 568 return (0); 569 } 570 571