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 NULL, 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 options = node_options(node); 235 options = concat(adr->adr_options, ',', options); 236 237 /* 238 * Prepend options passed via automountd(8) command line. 239 */ 240 if (cmdline_options != NULL) 241 options = concat(cmdline_options, ',', options); 242 243 if (node->n_location == NULL) { 244 log_debugx("found node defined at %s:%d; not a mountpoint", 245 node->n_config_file, node->n_config_line); 246 247 nobrowse = pick_option("nobrowse", &options); 248 if (nobrowse != NULL && adr->adr_key[0] == '\0') { 249 log_debugx("skipping map %s due to \"nobrowse\" " 250 "option; exiting", map); 251 done(0, true); 252 253 /* 254 * Exit without calling exit_callback(). 255 */ 256 quick_exit(0); 257 } 258 259 /* 260 * Not a mountpoint; create directories in the autofs mount 261 * and complete the request. 262 */ 263 create_subtree(node, incomplete_hierarchy); 264 265 if (incomplete_hierarchy && adr->adr_key[0] != '\0') { 266 /* 267 * We still need to create the single subdirectory 268 * user is trying to access. 269 */ 270 tmp = concat(adr->adr_path, '/', adr->adr_key); 271 node = node_find(root, tmp); 272 if (node != NULL) 273 create_subtree(node, false); 274 } 275 276 log_debugx("nothing to mount; exiting"); 277 done(0, wildcards); 278 279 /* 280 * Exit without calling exit_callback(). 281 */ 282 quick_exit(0); 283 } 284 285 log_debugx("found node defined at %s:%d; it is a mountpoint", 286 node->n_config_file, node->n_config_line); 287 288 node_expand_ampersand(node, 289 adr->adr_key[0] != '\0' ? adr->adr_key : NULL); 290 error = node_expand_defined(node); 291 if (error != 0) { 292 log_errx(1, "variable expansion failed for %s; " 293 "failing mount", adr->adr_path); 294 } 295 296 /* 297 * Append "automounted". 298 */ 299 options = concat(options, ',', "automounted"); 300 301 /* 302 * Remove "nobrowse", mount(8) doesn't understand it. 303 */ 304 pick_option("nobrowse", &options); 305 306 /* 307 * Figure out fstype. 308 */ 309 fstype = pick_option("fstype=", &options); 310 if (fstype == NULL) { 311 log_debugx("fstype not specified in options; " 312 "defaulting to \"nfs\""); 313 fstype = checked_strdup("nfs"); 314 } 315 316 if (strcmp(fstype, "nfs") == 0) { 317 /* 318 * The mount_nfs(8) command defaults to retry undefinitely. 319 * We do not want that behaviour, because it leaves mount_nfs(8) 320 * instances and automountd(8) children hanging forever. 321 * Disable retries unless the option was passed explicitly. 322 */ 323 retrycnt = pick_option("retrycnt=", &options); 324 if (retrycnt == NULL) { 325 log_debugx("retrycnt not specified in options; " 326 "defaulting to 1"); 327 options = concat(options, ',', "retrycnt=1"); 328 } else { 329 options = concat(options, ',', 330 concat("retrycnt", '=', retrycnt)); 331 } 332 } 333 334 f = auto_popen("mount", "-t", fstype, "-o", options, 335 node->n_location, adr->adr_path, NULL); 336 assert(f != NULL); 337 error = auto_pclose(f); 338 if (error != 0) 339 log_errx(1, "mount failed"); 340 341 log_debugx("mount done; exiting"); 342 done(0, wildcards); 343 344 /* 345 * Exit without calling exit_callback(). 346 */ 347 quick_exit(0); 348 } 349 350 static void 351 sigchld_handler(int dummy __unused) 352 { 353 354 /* 355 * The only purpose of this handler is to make SIGCHLD 356 * interrupt the AUTOFSREQUEST ioctl(2), so we can call 357 * wait_for_children(). 358 */ 359 } 360 361 static void 362 register_sigchld(void) 363 { 364 struct sigaction sa; 365 int error; 366 367 bzero(&sa, sizeof(sa)); 368 sa.sa_handler = sigchld_handler; 369 sigfillset(&sa.sa_mask); 370 error = sigaction(SIGCHLD, &sa, NULL); 371 if (error != 0) 372 log_err(1, "sigaction"); 373 374 } 375 376 377 static int 378 wait_for_children(bool block) 379 { 380 pid_t pid; 381 int status; 382 int num = 0; 383 384 for (;;) { 385 /* 386 * If "block" is true, wait for at least one process. 387 */ 388 if (block && num == 0) 389 pid = wait4(-1, &status, 0, NULL); 390 else 391 pid = wait4(-1, &status, WNOHANG, NULL); 392 if (pid <= 0) 393 break; 394 if (WIFSIGNALED(status)) { 395 log_warnx("child process %d terminated with signal %d", 396 pid, WTERMSIG(status)); 397 } else if (WEXITSTATUS(status) != 0) { 398 log_debugx("child process %d terminated with exit status %d", 399 pid, WEXITSTATUS(status)); 400 } else { 401 log_debugx("child process %d terminated gracefully", pid); 402 } 403 num++; 404 } 405 406 return (num); 407 } 408 409 static void 410 usage_automountd(void) 411 { 412 413 fprintf(stderr, "usage: automountd [-D name=value][-m maxproc]" 414 "[-o opts][-Tidv]\n"); 415 exit(1); 416 } 417 418 int 419 main_automountd(int argc, char **argv) 420 { 421 struct pidfh *pidfh; 422 pid_t pid, otherpid; 423 const char *pidfile_path = AUTOMOUNTD_PIDFILE; 424 char *options = NULL; 425 struct autofs_daemon_request request; 426 int ch, debug = 0, error, maxproc = 30, retval, saved_errno; 427 bool dont_daemonize = false, incomplete_hierarchy = false; 428 429 defined_init(); 430 431 while ((ch = getopt(argc, argv, "D:Tdim:o:v")) != -1) { 432 switch (ch) { 433 case 'D': 434 defined_parse_and_add(optarg); 435 break; 436 case 'T': 437 /* 438 * For compatibility with other implementations, 439 * such as OS X. 440 */ 441 debug++; 442 break; 443 case 'd': 444 dont_daemonize = true; 445 debug++; 446 break; 447 case 'i': 448 incomplete_hierarchy = true; 449 break; 450 case 'm': 451 maxproc = atoi(optarg); 452 break; 453 case 'o': 454 if (options == NULL) { 455 options = checked_strdup(optarg); 456 } else { 457 options = concat(options, ',', optarg); 458 } 459 break; 460 case 'v': 461 debug++; 462 break; 463 case '?': 464 default: 465 usage_automountd(); 466 } 467 } 468 argc -= optind; 469 if (argc != 0) 470 usage_automountd(); 471 472 log_init(debug); 473 474 pidfh = pidfile_open(pidfile_path, 0600, &otherpid); 475 if (pidfh == NULL) { 476 if (errno == EEXIST) { 477 log_errx(1, "daemon already running, pid: %jd.", 478 (intmax_t)otherpid); 479 } 480 log_err(1, "cannot open or create pidfile \"%s\"", 481 pidfile_path); 482 } 483 484 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 485 if (autofs_fd < 0 && errno == ENOENT) { 486 saved_errno = errno; 487 retval = kldload("autofs"); 488 if (retval != -1) 489 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 490 else 491 errno = saved_errno; 492 } 493 if (autofs_fd < 0) 494 log_err(1, "failed to open %s", AUTOFS_PATH); 495 496 if (dont_daemonize == false) { 497 if (daemon(0, 0) == -1) { 498 log_warn("cannot daemonize"); 499 pidfile_remove(pidfh); 500 exit(1); 501 } 502 } else { 503 lesser_daemon(); 504 } 505 506 pidfile_write(pidfh); 507 508 register_sigchld(); 509 510 for (;;) { 511 log_debugx("waiting for request from the kernel"); 512 513 memset(&request, 0, sizeof(request)); 514 error = ioctl(autofs_fd, AUTOFSREQUEST, &request); 515 if (error != 0) { 516 if (errno == EINTR) { 517 nchildren -= wait_for_children(false); 518 assert(nchildren >= 0); 519 continue; 520 } 521 522 log_err(1, "AUTOFSREQUEST"); 523 } 524 525 if (dont_daemonize) { 526 log_debugx("not forking due to -d flag; " 527 "will exit after servicing a single request"); 528 } else { 529 nchildren -= wait_for_children(false); 530 assert(nchildren >= 0); 531 532 while (maxproc > 0 && nchildren >= maxproc) { 533 log_debugx("maxproc limit of %d child processes hit; " 534 "waiting for child process to exit", maxproc); 535 nchildren -= wait_for_children(true); 536 assert(nchildren >= 0); 537 } 538 log_debugx("got request; forking child process #%d", 539 nchildren); 540 nchildren++; 541 542 pid = fork(); 543 if (pid < 0) 544 log_err(1, "fork"); 545 if (pid > 0) 546 continue; 547 } 548 549 pidfile_close(pidfh); 550 handle_request(&request, options, incomplete_hierarchy); 551 } 552 553 pidfile_close(pidfh); 554 555 return (0); 556 } 557 558