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/cdefs.h>
33 #include <sys/types.h>
34 #include <sys/time.h>
35 #include <sys/ioctl.h>
36 #include <sys/param.h>
37 #include <sys/linker.h>
38 #include <sys/mount.h>
39 #include <sys/socket.h>
40 #include <sys/stat.h>
41 #include <sys/wait.h>
42 #include <sys/utsname.h>
43 #include <assert.h>
44 #include <ctype.h>
45 #include <errno.h>
46 #include <fcntl.h>
47 #include <libgen.h>
48 #include <libutil.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 "autofs_ioctl.h"
59
60 #include "common.h"
61
62 #define AUTOMOUNTD_PIDFILE "/var/run/automountd.pid"
63
64 static int nchildren = 0;
65 static int autofs_fd;
66 static int request_id;
67
68 static void
done(int request_error,bool wildcards)69 done(int request_error, bool wildcards)
70 {
71 struct autofs_daemon_done add;
72 int error;
73
74 memset(&add, 0, sizeof(add));
75 add.add_id = request_id;
76 add.add_wildcards = wildcards;
77 add.add_error = request_error;
78
79 log_debugx("completing request %d with error %d",
80 request_id, request_error);
81
82 error = ioctl(autofs_fd, AUTOFSDONE, &add);
83 if (error != 0)
84 log_warn("AUTOFSDONE");
85 }
86
87 /*
88 * Remove "fstype=whatever" from optionsp and return the "whatever" part.
89 */
90 static char *
pick_option(const char * option,char ** optionsp)91 pick_option(const char *option, char **optionsp)
92 {
93 char *tofree, *pair, *newoptions;
94 char *picked = NULL;
95 bool first = true;
96
97 tofree = *optionsp;
98
99 newoptions = calloc(1, strlen(*optionsp) + 1);
100 if (newoptions == NULL)
101 log_err(1, "calloc");
102
103 while ((pair = strsep(optionsp, ",")) != NULL) {
104 /*
105 * XXX: strncasecmp(3) perhaps?
106 */
107 if (strncmp(pair, option, strlen(option)) == 0) {
108 picked = checked_strdup(pair + strlen(option));
109 } else {
110 if (first == false)
111 strcat(newoptions, ",");
112 else
113 first = false;
114 strcat(newoptions, pair);
115 }
116 }
117
118 free(tofree);
119 *optionsp = newoptions;
120
121 return (picked);
122 }
123
124 static void
create_subtree(const struct node * node,bool incomplete)125 create_subtree(const struct node *node, bool incomplete)
126 {
127 const struct node *child;
128 char *path;
129 bool wildcard_found = false;
130
131 /*
132 * Skip wildcard nodes.
133 */
134 if (strcmp(node->n_key, "*") == 0)
135 return;
136
137 path = node_path(node);
138 log_debugx("creating subtree at %s", path);
139 create_directory(path);
140
141 if (incomplete) {
142 TAILQ_FOREACH(child, &node->n_children, n_next) {
143 if (strcmp(child->n_key, "*") == 0) {
144 wildcard_found = true;
145 break;
146 }
147 }
148
149 if (wildcard_found) {
150 log_debugx("node %s contains wildcard entry; "
151 "not creating its subdirectories due to -d flag",
152 path);
153 free(path);
154 return;
155 }
156 }
157
158 free(path);
159
160 TAILQ_FOREACH(child, &node->n_children, n_next)
161 create_subtree(child, incomplete);
162 }
163
164 static void
exit_callback(void)165 exit_callback(void)
166 {
167
168 done(EIO, true);
169 }
170
171 static void
handle_request(const struct autofs_daemon_request * adr,char * cmdline_options,bool incomplete_hierarchy)172 handle_request(const struct autofs_daemon_request *adr, char *cmdline_options,
173 bool incomplete_hierarchy)
174 {
175 const char *map;
176 struct node *root, *parent, *node;
177 FILE *f;
178 char *key, *options, *fstype, *nobrowse, *retrycnt, *tmp;
179 int error;
180 bool wildcards;
181
182 log_debugx("got request %d: from %s, path %s, prefix \"%s\", "
183 "key \"%s\", options \"%s\"", adr->adr_id, adr->adr_from,
184 adr->adr_path, adr->adr_prefix, adr->adr_key, adr->adr_options);
185
186 /*
187 * Try to notify the kernel about any problems.
188 */
189 request_id = adr->adr_id;
190 atexit(exit_callback);
191
192 if (strncmp(adr->adr_from, "map ", 4) != 0) {
193 log_errx(1, "invalid mountfrom \"%s\"; failing request",
194 adr->adr_from);
195 }
196
197 map = adr->adr_from + 4; /* 4 for strlen("map "); */
198 root = node_new_root();
199 if (adr->adr_prefix[0] == '\0' || strcmp(adr->adr_prefix, "/") == 0) {
200 /*
201 * Direct map. autofs(4) doesn't have a way to determine
202 * correct map key, but since it's a direct map, we can just
203 * use adr_path instead.
204 */
205 parent = root;
206 key = checked_strdup(adr->adr_path);
207 } else {
208 /*
209 * Indirect map.
210 */
211 parent = node_new_map(root, checked_strdup(adr->adr_prefix),
212 NULL, checked_strdup(map),
213 checked_strdup("[kernel request]"), lineno);
214
215 if (adr->adr_key[0] == '\0')
216 key = NULL;
217 else
218 key = checked_strdup(adr->adr_key);
219 }
220
221 /*
222 * "Wildcards" here actually means "make autofs(4) request
223 * automountd(8) action if the node being looked up does not
224 * exist, even though the parent is marked as cached". This
225 * needs to be done for maps with wildcard entries, but also
226 * for special and executable maps.
227 */
228 parse_map(parent, map, key, &wildcards);
229 if (!wildcards)
230 wildcards = node_has_wildcards(parent);
231 if (wildcards)
232 log_debugx("map may contain wildcard entries");
233 else
234 log_debugx("map does not contain wildcard entries");
235
236 if (key != NULL)
237 node_expand_wildcard(root, key);
238
239 node = node_find(root, adr->adr_path);
240 if (node == NULL) {
241 log_errx(1, "map %s does not contain key for \"%s\"; "
242 "failing mount", map, adr->adr_path);
243 }
244
245 options = node_options(node);
246
247 /*
248 * Append options from auto_master.
249 */
250 options = concat(options, ',', adr->adr_options);
251
252 /*
253 * Prepend options passed via automountd(8) command line.
254 */
255 options = concat(cmdline_options, ',', options);
256
257 if (node->n_location == NULL) {
258 log_debugx("found node defined at %s:%d; not a mountpoint",
259 node->n_config_file, node->n_config_line);
260
261 nobrowse = pick_option("nobrowse", &options);
262 if (nobrowse != NULL && key == NULL) {
263 log_debugx("skipping map %s due to \"nobrowse\" "
264 "option; exiting", map);
265 done(0, true);
266
267 /*
268 * Exit without calling exit_callback().
269 */
270 quick_exit(0);
271 }
272
273 /*
274 * Not a mountpoint; create directories in the autofs mount
275 * and complete the request.
276 */
277 create_subtree(node, incomplete_hierarchy);
278
279 if (incomplete_hierarchy && key != NULL) {
280 /*
281 * We still need to create the single subdirectory
282 * user is trying to access.
283 */
284 tmp = concat(adr->adr_path, '/', key);
285 node = node_find(root, tmp);
286 if (node != NULL)
287 create_subtree(node, false);
288 }
289
290 log_debugx("nothing to mount; exiting");
291 done(0, wildcards);
292
293 /*
294 * Exit without calling exit_callback().
295 */
296 quick_exit(0);
297 }
298
299 log_debugx("found node defined at %s:%d; it is a mountpoint",
300 node->n_config_file, node->n_config_line);
301
302 if (key != NULL)
303 node_expand_ampersand(node, key);
304 error = node_expand_defined(node);
305 if (error != 0) {
306 log_errx(1, "variable expansion failed for %s; "
307 "failing mount", adr->adr_path);
308 }
309
310 /*
311 * Append "automounted".
312 */
313 options = concat(options, ',', "automounted");
314
315 /*
316 * Remove "nobrowse", mount(8) doesn't understand it.
317 */
318 pick_option("nobrowse", &options);
319
320 /*
321 * Figure out fstype.
322 */
323 fstype = pick_option("fstype=", &options);
324 if (fstype == NULL) {
325 log_debugx("fstype not specified in options; "
326 "defaulting to \"nfs\"");
327 fstype = checked_strdup("nfs");
328 }
329
330 if (strcmp(fstype, "nfs") == 0) {
331 /*
332 * The mount_nfs(8) command defaults to retry undefinitely.
333 * We do not want that behaviour, because it leaves mount_nfs(8)
334 * instances and automountd(8) children hanging forever.
335 * Disable retries unless the option was passed explicitly.
336 */
337 retrycnt = pick_option("retrycnt=", &options);
338 if (retrycnt == NULL) {
339 log_debugx("retrycnt not specified in options; "
340 "defaulting to 1");
341 options = concat(options, ',', "retrycnt=1");
342 } else {
343 options = concat(options, ',',
344 concat("retrycnt", '=', retrycnt));
345 }
346 }
347
348 f = auto_popen("mount", "-t", fstype, "-o", options,
349 node->n_location, adr->adr_path, NULL);
350 assert(f != NULL);
351 error = auto_pclose(f);
352 if (error != 0)
353 log_errx(1, "mount failed");
354
355 log_debugx("mount done; exiting");
356 done(0, wildcards);
357
358 /*
359 * Exit without calling exit_callback().
360 */
361 quick_exit(0);
362 }
363
364 static void
sigchld_handler(int dummy __unused)365 sigchld_handler(int dummy __unused)
366 {
367
368 /*
369 * The only purpose of this handler is to make SIGCHLD
370 * interrupt the AUTOFSREQUEST ioctl(2), so we can call
371 * wait_for_children().
372 */
373 }
374
375 static void
register_sigchld(void)376 register_sigchld(void)
377 {
378 struct sigaction sa;
379 int error;
380
381 bzero(&sa, sizeof(sa));
382 sa.sa_handler = sigchld_handler;
383 sigfillset(&sa.sa_mask);
384 error = sigaction(SIGCHLD, &sa, NULL);
385 if (error != 0)
386 log_err(1, "sigaction");
387
388 }
389
390
391 static int
wait_for_children(bool block)392 wait_for_children(bool block)
393 {
394 pid_t pid;
395 int status;
396 int num = 0;
397
398 for (;;) {
399 /*
400 * If "block" is true, wait for at least one process.
401 */
402 if (block && num == 0)
403 pid = wait4(-1, &status, 0, NULL);
404 else
405 pid = wait4(-1, &status, WNOHANG, NULL);
406 if (pid <= 0)
407 break;
408 if (WIFSIGNALED(status)) {
409 log_warnx("child process %d terminated with signal %d",
410 pid, WTERMSIG(status));
411 } else if (WEXITSTATUS(status) != 0) {
412 log_debugx("child process %d terminated with exit status %d",
413 pid, WEXITSTATUS(status));
414 } else {
415 log_debugx("child process %d terminated gracefully", pid);
416 }
417 num++;
418 }
419
420 return (num);
421 }
422
423 static void
usage_automountd(void)424 usage_automountd(void)
425 {
426
427 fprintf(stderr, "usage: automountd [-D name=value][-m maxproc]"
428 "[-o opts][-Tidv]\n");
429 exit(1);
430 }
431
432 int
main_automountd(int argc,char ** argv)433 main_automountd(int argc, char **argv)
434 {
435 struct pidfh *pidfh;
436 pid_t pid, otherpid;
437 const char *pidfile_path = AUTOMOUNTD_PIDFILE;
438 char *options = NULL;
439 struct autofs_daemon_request request;
440 int ch, debug = 0, error, maxproc = 30, retval, saved_errno;
441 bool dont_daemonize = false, incomplete_hierarchy = false;
442
443 defined_init();
444
445 while ((ch = getopt(argc, argv, "D:Tdim:o:v")) != -1) {
446 switch (ch) {
447 case 'D':
448 defined_parse_and_add(optarg);
449 break;
450 case 'T':
451 /*
452 * For compatibility with other implementations,
453 * such as OS X.
454 */
455 debug++;
456 break;
457 case 'd':
458 dont_daemonize = true;
459 debug++;
460 break;
461 case 'i':
462 incomplete_hierarchy = true;
463 break;
464 case 'm':
465 maxproc = atoi(optarg);
466 break;
467 case 'o':
468 options = concat(options, ',', optarg);
469 break;
470 case 'v':
471 debug++;
472 break;
473 case '?':
474 default:
475 usage_automountd();
476 }
477 }
478 argc -= optind;
479 if (argc != 0)
480 usage_automountd();
481
482 log_init(debug);
483
484 pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
485 if (pidfh == NULL) {
486 if (errno == EEXIST) {
487 log_errx(1, "daemon already running, pid: %jd.",
488 (intmax_t)otherpid);
489 }
490 log_err(1, "cannot open or create pidfile \"%s\"",
491 pidfile_path);
492 }
493
494 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC);
495 if (autofs_fd < 0 && errno == ENOENT) {
496 saved_errno = errno;
497 retval = kldload("autofs");
498 if (retval != -1)
499 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC);
500 else
501 errno = saved_errno;
502 }
503 if (autofs_fd < 0)
504 log_err(1, "failed to open %s", AUTOFS_PATH);
505
506 if (dont_daemonize == false) {
507 if (daemon(0, 0) == -1) {
508 log_warn("cannot daemonize");
509 pidfile_remove(pidfh);
510 exit(1);
511 }
512 } else {
513 lesser_daemon();
514 }
515
516 pidfile_write(pidfh);
517
518 register_sigchld();
519
520 for (;;) {
521 log_debugx("waiting for request from the kernel");
522
523 memset(&request, 0, sizeof(request));
524 error = ioctl(autofs_fd, AUTOFSREQUEST, &request);
525 if (error != 0) {
526 if (errno == EINTR) {
527 nchildren -= wait_for_children(false);
528 assert(nchildren >= 0);
529 continue;
530 }
531
532 log_err(1, "AUTOFSREQUEST");
533 }
534
535 if (dont_daemonize) {
536 log_debugx("not forking due to -d flag; "
537 "will exit after servicing a single request");
538 } else {
539 nchildren -= wait_for_children(false);
540 assert(nchildren >= 0);
541
542 while (maxproc > 0 && nchildren >= maxproc) {
543 log_debugx("maxproc limit of %d child processes hit; "
544 "waiting for child process to exit", maxproc);
545 nchildren -= wait_for_children(true);
546 assert(nchildren >= 0);
547 }
548 log_debugx("got request; forking child process #%d",
549 nchildren);
550 nchildren++;
551
552 pid = fork();
553 if (pid < 0)
554 log_err(1, "fork");
555 if (pid > 0)
556 continue;
557 }
558
559 pidfile_close(pidfh);
560 handle_request(&request, options, incomplete_hierarchy);
561 }
562
563 pidfile_close(pidfh);
564
565 return (0);
566 }
567
568