automountd.c revision 283238
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: stable/10/usr.sbin/autofs/automountd.c 283238 2015-05-21 13:36:00Z trasz $"); 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 66static int nchildren = 0; 67static int autofs_fd; 68static int request_id; 69 70static void 71done(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 */ 92static char * 93pick_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 126static void 127create_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 166static void 167exit_callback(void) 168{ 169 170 done(EIO, true); 171} 172 173static void 174handle_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); 235 236 /* 237 * Append options from auto_master. 238 */ 239 options = concat(options, ',', adr->adr_options); 240 241 /* 242 * Prepend options passed via automountd(8) command line. 243 */ 244 options = concat(cmdline_options, ',', options); 245 246 if (node->n_location == NULL) { 247 log_debugx("found node defined at %s:%d; not a mountpoint", 248 node->n_config_file, node->n_config_line); 249 250 nobrowse = pick_option("nobrowse", &options); 251 if (nobrowse != NULL && adr->adr_key[0] == '\0') { 252 log_debugx("skipping map %s due to \"nobrowse\" " 253 "option; exiting", map); 254 done(0, true); 255 256 /* 257 * Exit without calling exit_callback(). 258 */ 259 quick_exit(0); 260 } 261 262 /* 263 * Not a mountpoint; create directories in the autofs mount 264 * and complete the request. 265 */ 266 create_subtree(node, incomplete_hierarchy); 267 268 if (incomplete_hierarchy && adr->adr_key[0] != '\0') { 269 /* 270 * We still need to create the single subdirectory 271 * user is trying to access. 272 */ 273 tmp = concat(adr->adr_path, '/', adr->adr_key); 274 node = node_find(root, tmp); 275 if (node != NULL) 276 create_subtree(node, false); 277 } 278 279 log_debugx("nothing to mount; exiting"); 280 done(0, wildcards); 281 282 /* 283 * Exit without calling exit_callback(). 284 */ 285 quick_exit(0); 286 } 287 288 log_debugx("found node defined at %s:%d; it is a mountpoint", 289 node->n_config_file, node->n_config_line); 290 291 node_expand_ampersand(node, 292 adr->adr_key[0] != '\0' ? adr->adr_key : NULL); 293 error = node_expand_defined(node); 294 if (error != 0) { 295 log_errx(1, "variable expansion failed for %s; " 296 "failing mount", adr->adr_path); 297 } 298 299 /* 300 * Append "automounted". 301 */ 302 options = concat(options, ',', "automounted"); 303 304 /* 305 * Remove "nobrowse", mount(8) doesn't understand it. 306 */ 307 pick_option("nobrowse", &options); 308 309 /* 310 * Figure out fstype. 311 */ 312 fstype = pick_option("fstype=", &options); 313 if (fstype == NULL) { 314 log_debugx("fstype not specified in options; " 315 "defaulting to \"nfs\""); 316 fstype = checked_strdup("nfs"); 317 } 318 319 if (strcmp(fstype, "nfs") == 0) { 320 /* 321 * The mount_nfs(8) command defaults to retry undefinitely. 322 * We do not want that behaviour, because it leaves mount_nfs(8) 323 * instances and automountd(8) children hanging forever. 324 * Disable retries unless the option was passed explicitly. 325 */ 326 retrycnt = pick_option("retrycnt=", &options); 327 if (retrycnt == NULL) { 328 log_debugx("retrycnt not specified in options; " 329 "defaulting to 1"); 330 options = concat(options, ',', "retrycnt=1"); 331 } else { 332 options = concat(options, ',', 333 concat("retrycnt", '=', retrycnt)); 334 } 335 } 336 337 f = auto_popen("mount", "-t", fstype, "-o", options, 338 node->n_location, adr->adr_path, NULL); 339 assert(f != NULL); 340 error = auto_pclose(f); 341 if (error != 0) 342 log_errx(1, "mount failed"); 343 344 log_debugx("mount done; exiting"); 345 done(0, wildcards); 346 347 /* 348 * Exit without calling exit_callback(). 349 */ 350 quick_exit(0); 351} 352 353static void 354sigchld_handler(int dummy __unused) 355{ 356 357 /* 358 * The only purpose of this handler is to make SIGCHLD 359 * interrupt the AUTOFSREQUEST ioctl(2), so we can call 360 * wait_for_children(). 361 */ 362} 363 364static void 365register_sigchld(void) 366{ 367 struct sigaction sa; 368 int error; 369 370 bzero(&sa, sizeof(sa)); 371 sa.sa_handler = sigchld_handler; 372 sigfillset(&sa.sa_mask); 373 error = sigaction(SIGCHLD, &sa, NULL); 374 if (error != 0) 375 log_err(1, "sigaction"); 376 377} 378 379 380static int 381wait_for_children(bool block) 382{ 383 pid_t pid; 384 int status; 385 int num = 0; 386 387 for (;;) { 388 /* 389 * If "block" is true, wait for at least one process. 390 */ 391 if (block && num == 0) 392 pid = wait4(-1, &status, 0, NULL); 393 else 394 pid = wait4(-1, &status, WNOHANG, NULL); 395 if (pid <= 0) 396 break; 397 if (WIFSIGNALED(status)) { 398 log_warnx("child process %d terminated with signal %d", 399 pid, WTERMSIG(status)); 400 } else if (WEXITSTATUS(status) != 0) { 401 log_debugx("child process %d terminated with exit status %d", 402 pid, WEXITSTATUS(status)); 403 } else { 404 log_debugx("child process %d terminated gracefully", pid); 405 } 406 num++; 407 } 408 409 return (num); 410} 411 412static void 413usage_automountd(void) 414{ 415 416 fprintf(stderr, "usage: automountd [-D name=value][-m maxproc]" 417 "[-o opts][-Tidv]\n"); 418 exit(1); 419} 420 421int 422main_automountd(int argc, char **argv) 423{ 424 struct pidfh *pidfh; 425 pid_t pid, otherpid; 426 const char *pidfile_path = AUTOMOUNTD_PIDFILE; 427 char *options = NULL; 428 struct autofs_daemon_request request; 429 int ch, debug = 0, error, maxproc = 30, retval, saved_errno; 430 bool dont_daemonize = false, incomplete_hierarchy = false; 431 432 defined_init(); 433 434 while ((ch = getopt(argc, argv, "D:Tdim:o:v")) != -1) { 435 switch (ch) { 436 case 'D': 437 defined_parse_and_add(optarg); 438 break; 439 case 'T': 440 /* 441 * For compatibility with other implementations, 442 * such as OS X. 443 */ 444 debug++; 445 break; 446 case 'd': 447 dont_daemonize = true; 448 debug++; 449 break; 450 case 'i': 451 incomplete_hierarchy = true; 452 break; 453 case 'm': 454 maxproc = atoi(optarg); 455 break; 456 case 'o': 457 options = concat(options, ',', optarg); 458 break; 459 case 'v': 460 debug++; 461 break; 462 case '?': 463 default: 464 usage_automountd(); 465 } 466 } 467 argc -= optind; 468 if (argc != 0) 469 usage_automountd(); 470 471 log_init(debug); 472 473 pidfh = pidfile_open(pidfile_path, 0600, &otherpid); 474 if (pidfh == NULL) { 475 if (errno == EEXIST) { 476 log_errx(1, "daemon already running, pid: %jd.", 477 (intmax_t)otherpid); 478 } 479 log_err(1, "cannot open or create pidfile \"%s\"", 480 pidfile_path); 481 } 482 483 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 484 if (autofs_fd < 0 && errno == ENOENT) { 485 saved_errno = errno; 486 retval = kldload("autofs"); 487 if (retval != -1) 488 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC); 489 else 490 errno = saved_errno; 491 } 492 if (autofs_fd < 0) 493 log_err(1, "failed to open %s", AUTOFS_PATH); 494 495 if (dont_daemonize == false) { 496 if (daemon(0, 0) == -1) { 497 log_warn("cannot daemonize"); 498 pidfile_remove(pidfh); 499 exit(1); 500 } 501 } else { 502 lesser_daemon(); 503 } 504 505 pidfile_write(pidfh); 506 507 register_sigchld(); 508 509 for (;;) { 510 log_debugx("waiting for request from the kernel"); 511 512 memset(&request, 0, sizeof(request)); 513 error = ioctl(autofs_fd, AUTOFSREQUEST, &request); 514 if (error != 0) { 515 if (errno == EINTR) { 516 nchildren -= wait_for_children(false); 517 assert(nchildren >= 0); 518 continue; 519 } 520 521 log_err(1, "AUTOFSREQUEST"); 522 } 523 524 if (dont_daemonize) { 525 log_debugx("not forking due to -d flag; " 526 "will exit after servicing a single request"); 527 } else { 528 nchildren -= wait_for_children(false); 529 assert(nchildren >= 0); 530 531 while (maxproc > 0 && nchildren >= maxproc) { 532 log_debugx("maxproc limit of %d child processes hit; " 533 "waiting for child process to exit", maxproc); 534 nchildren -= wait_for_children(true); 535 assert(nchildren >= 0); 536 } 537 log_debugx("got request; forking child process #%d", 538 nchildren); 539 nchildren++; 540 541 pid = fork(); 542 if (pid < 0) 543 log_err(1, "fork"); 544 if (pid > 0) 545 continue; 546 } 547 548 pidfile_close(pidfh); 549 handle_request(&request, options, incomplete_hierarchy); 550 } 551 552 pidfile_close(pidfh); 553 554 return (0); 555} 556 557