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