1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 2016 The DragonFly Project
5 * Copyright (c) 2014 The FreeBSD Foundation
6 * All rights reserved.
7 *
8 * This software was developed by Edward Tomasz Napierala under sponsorship
9 * from the FreeBSD Foundation.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 */
33
34 #include <sys/types.h>
35 #include <sys/ioctl.h>
36 #include <sys/linker.h>
37 #include <sys/wait.h>
38 #include <assert.h>
39 #include <errno.h>
40 #include <fcntl.h>
41 #include <signal.h>
42 #include <stdio.h>
43 #include <stdlib.h>
44 #include <string.h>
45 #include <unistd.h>
46 #include <libutil.h>
47 #include <vfs/autofs/autofs_ioctl.h>
48
49 #include "common.h"
50
51 #define AUTOMOUNTD_PIDFILE "/var/run/automountd.pid"
52
53 static int nchildren = 0;
54 static int autofs_fd;
55 static int request_id;
56
57 static void
done(int request_error,bool wildcards)58 done(int request_error, bool wildcards)
59 {
60 struct autofs_daemon_done add;
61 int error;
62
63 memset(&add, 0, sizeof(add));
64 add.add_id = request_id;
65 add.add_wildcards = wildcards;
66 add.add_error = request_error;
67
68 log_debugx("completing request %d with error %d",
69 request_id, request_error);
70
71 error = ioctl(autofs_fd, AUTOFSDONE, &add);
72 if (error != 0)
73 log_warn("AUTOFSDONE");
74 }
75
76 /*
77 * Remove "fstype=whatever" from optionsp and return the "whatever" part.
78 */
79 static char *
pick_option(const char * option,char ** optionsp)80 pick_option(const char *option, char **optionsp)
81 {
82 char *tofree, *pair, *newoptions;
83 char *picked = NULL;
84 bool first = true;
85
86 tofree = *optionsp;
87
88 newoptions = calloc(1, strlen(*optionsp) + 1);
89 if (newoptions == NULL)
90 log_err(1, "calloc");
91
92 while ((pair = strsep(optionsp, ",")) != NULL) {
93 /*
94 * XXX: strncasecmp(3) perhaps?
95 */
96 if (strncmp(pair, option, strlen(option)) == 0) {
97 picked = checked_strdup(pair + strlen(option));
98 } else {
99 if (first == false)
100 strcat(newoptions, ",");
101 else
102 first = false;
103 strcat(newoptions, pair);
104 }
105 }
106
107 free(tofree);
108 *optionsp = newoptions;
109
110 return (picked);
111 }
112
113 static void
create_subtree(const struct node * node,bool incomplete)114 create_subtree(const struct node *node, bool incomplete)
115 {
116 const struct node *child;
117 char *path;
118 bool wildcard_found = false;
119
120 /*
121 * Skip wildcard nodes.
122 */
123 if (strcmp(node->n_key, "*") == 0)
124 return;
125
126 path = node_path(node);
127 log_debugx("creating subtree at %s", path);
128 create_directory(path);
129
130 if (incomplete) {
131 TAILQ_FOREACH(child, &node->n_children, n_next) {
132 if (strcmp(child->n_key, "*") == 0) {
133 wildcard_found = true;
134 break;
135 }
136 }
137
138 if (wildcard_found) {
139 log_debugx("node %s contains wildcard entry; "
140 "not creating its subdirectories due to -d flag",
141 path);
142 free(path);
143 return;
144 }
145 }
146
147 free(path);
148
149 TAILQ_FOREACH(child, &node->n_children, n_next)
150 create_subtree(child, incomplete);
151 }
152
153 static void
exit_callback(void)154 exit_callback(void)
155 {
156
157 done(EIO, true);
158 }
159
160 static void
handle_request(const struct autofs_daemon_request * adr,char * cmdline_options,bool incomplete_hierarchy)161 handle_request(const struct autofs_daemon_request *adr, char *cmdline_options,
162 bool incomplete_hierarchy)
163 {
164 const char *map;
165 struct node *root, *parent, *node;
166 FILE *f;
167 char *key, *options, *fstype, *nobrowse, *retrycnt, *tmp;
168 int error;
169 bool wildcards;
170
171 log_debugx("got request %d: from %s, path %s, prefix \"%s\", "
172 "key \"%s\", options \"%s\"", adr->adr_id, adr->adr_from,
173 adr->adr_path, adr->adr_prefix, adr->adr_key, adr->adr_options);
174
175 /*
176 * Try to notify the kernel about any problems.
177 */
178 request_id = adr->adr_id;
179 atexit(exit_callback);
180
181 if (strncmp(adr->adr_from, "map ", 4) != 0) {
182 log_errx(1, "invalid mountfrom \"%s\"; failing request",
183 adr->adr_from);
184 }
185
186 map = adr->adr_from + 4; /* 4 for strlen("map "); */
187 root = node_new_root();
188 if (adr->adr_prefix[0] == '\0' || strcmp(adr->adr_prefix, "/") == 0) {
189 /*
190 * Direct map. autofs(4) doesn't have a way to determine
191 * correct map key, but since it's a direct map, we can just
192 * use adr_path instead.
193 */
194 parent = root;
195 key = checked_strdup(adr->adr_path);
196 } else {
197 /*
198 * Indirect map.
199 */
200 parent = node_new_map(root, checked_strdup(adr->adr_prefix),
201 NULL, checked_strdup(map),
202 checked_strdup("[kernel request]"), lineno);
203
204 if (adr->adr_key[0] == '\0')
205 key = NULL;
206 else
207 key = checked_strdup(adr->adr_key);
208 }
209
210 /*
211 * "Wildcards" here actually means "make autofs(4) request
212 * automountd(8) action if the node being looked up does not
213 * exist, even though the parent is marked as cached". This
214 * needs to be done for maps with wildcard entries, but also
215 * for special and executable maps.
216 */
217 parse_map(parent, map, key, &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 (key != NULL)
226 node_expand_wildcard(root, 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 && key == NULL) {
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 && key != NULL) {
269 /*
270 * We still need to create the single subdirectory
271 * user is trying to access.
272 */
273 tmp = concat(adr->adr_path, '/', 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 if (key != NULL)
292 node_expand_ampersand(node, key);
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
353 static void
sigchld_handler(int dummy __unused)354 sigchld_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
364 static void
register_sigchld(void)365 register_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 static int
wait_for_children(bool block)380 wait_for_children(bool block)
381 {
382 pid_t pid;
383 int status;
384 int num = 0;
385
386 for (;;) {
387 /*
388 * If "block" is true, wait for at least one process.
389 */
390 if (block && num == 0)
391 pid = wait4(-1, &status, 0, NULL);
392 else
393 pid = wait4(-1, &status, WNOHANG, NULL);
394 if (pid <= 0)
395 break;
396 if (WIFSIGNALED(status)) {
397 log_warnx("child process %d terminated with signal %d",
398 pid, WTERMSIG(status));
399 } else if (WEXITSTATUS(status) != 0) {
400 log_debugx("child process %d terminated with exit status %d",
401 pid, WEXITSTATUS(status));
402 } else {
403 log_debugx("child process %d terminated gracefully", pid);
404 }
405 num++;
406 }
407
408 return (num);
409 }
410
411 static void
usage_automountd(void)412 usage_automountd(void)
413 {
414
415 fprintf(stderr, "usage: automountd [-D name=value][-m maxproc]"
416 "[-o opts][-Tidv]\n");
417 exit(1);
418 }
419
420 void
main_automountd(int argc,char ** argv)421 main_automountd(int argc, char **argv)
422 {
423 struct pidfh *pidfh;
424 pid_t pid, otherpid;
425 const char *pidfile_path = AUTOMOUNTD_PIDFILE;
426 char *options = NULL;
427 struct autofs_daemon_request request;
428 int ch, debug = 0, error, maxproc = 30, retval, saved_errno;
429 bool dont_daemonize = false, incomplete_hierarchy = false;
430
431 defined_init();
432
433 while ((ch = getopt(argc, argv, "D:Tdim:o:v")) != -1) {
434 switch (ch) {
435 case 'D':
436 defined_parse_and_add(optarg);
437 break;
438 case 'T':
439 /*
440 * For compatibility with other implementations,
441 * such as OS X.
442 */
443 debug++;
444 break;
445 case 'd':
446 dont_daemonize = true;
447 debug++;
448 break;
449 case 'i':
450 incomplete_hierarchy = true;
451 break;
452 case 'm':
453 maxproc = atoi(optarg);
454 break;
455 case 'o':
456 options = concat(options, ',', optarg);
457 break;
458 case 'v':
459 debug++;
460 break;
461 case '?':
462 default:
463 usage_automountd();
464 }
465 }
466 argc -= optind;
467 if (argc != 0)
468 usage_automountd();
469
470 log_init(debug);
471
472 pidfh = pidfile_open(pidfile_path, 0600, &otherpid);
473 if (pidfh == NULL) {
474 if (errno == EEXIST) {
475 log_errx(1, "daemon already running, pid: %jd.",
476 (intmax_t)otherpid);
477 }
478 log_err(1, "cannot open or create pidfile \"%s\"",
479 pidfile_path);
480 }
481
482 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC);
483 if (autofs_fd < 0 && errno == ENOENT) {
484 saved_errno = errno;
485 retval = kldload("autofs");
486 if (retval != -1)
487 autofs_fd = open(AUTOFS_PATH, O_RDWR | O_CLOEXEC);
488 else
489 errno = saved_errno;
490 }
491 if (autofs_fd < 0)
492 log_err(1, "failed to open %s", AUTOFS_PATH);
493
494 if (dont_daemonize == false) {
495 if (daemon(0, 0) == -1) {
496 log_warn("cannot daemonize");
497 pidfile_remove(pidfh);
498 exit(1);
499 }
500 } else {
501 lesser_daemon();
502 }
503
504 pidfile_write(pidfh);
505
506 register_sigchld();
507
508 for (;;) {
509 log_debugx("waiting for request from the kernel");
510
511 memset(&request, 0, sizeof(request));
512 error = ioctl(autofs_fd, AUTOFSREQUEST, &request);
513 if (error != 0) {
514 if (errno == EINTR) {
515 nchildren -= wait_for_children(false);
516 assert(nchildren >= 0);
517 continue;
518 }
519
520 log_err(1, "AUTOFSREQUEST");
521 }
522
523 if (dont_daemonize) {
524 log_debugx("not forking due to -d flag; "
525 "will exit after servicing a single request");
526 } else {
527 nchildren -= wait_for_children(false);
528 assert(nchildren >= 0);
529
530 while (maxproc > 0 && nchildren >= maxproc) {
531 log_debugx("maxproc limit of %d child processes hit; "
532 "waiting for child process to exit", maxproc);
533 nchildren -= wait_for_children(true);
534 assert(nchildren >= 0);
535 }
536 log_debugx("got request; forking child process #%d",
537 nchildren);
538 nchildren++;
539
540 pid = fork();
541 if (pid < 0)
542 log_err(1, "fork");
543 if (pid > 0)
544 continue;
545 }
546
547 pidfile_close(pidfh);
548 handle_request(&request, options, incomplete_hierarchy);
549 }
550 }
551