2 * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved
3 * Copyright 2001-2006 Ian Kent <raven@themaw.net>
5 * This file is part of the Linux kernel and is made available under
6 * the terms of the GNU General Public License, version 2, or at your
7 * option, any later version, incorporated herein by reference.
10 #include <linux/slab.h>
11 #include <linux/time.h>
12 #include <linux/signal.h>
13 #include <linux/sched/signal.h>
14 #include <linux/file.h>
17 /* We make this a static variable rather than a part of the superblock; it
18 * is better if we don't reassign numbers easily even across filesystems
20 static autofs_wqt_t autofs4_next_wait_queue = 1;
22 /* These are the signals we allow interrupting a pending mount */
23 #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))
25 void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
27 struct autofs_wait_queue *wq, *nwq;
29 mutex_lock(&sbi->wq_mutex);
31 mutex_unlock(&sbi->wq_mutex);
35 pr_debug("entering catatonic mode\n");
39 sbi->queues = NULL; /* Erase all wait queues */
42 wq->status = -ENOENT; /* Magic is gone - report failure */
45 wake_up_interruptible(&wq->queue);
50 fput(sbi->pipe); /* Close the pipe */
53 mutex_unlock(&sbi->wq_mutex);
56 static int autofs4_write(struct autofs_sb_info *sbi,
57 struct file *file, const void *addr, int bytes)
59 unsigned long sigpipe, flags;
60 const char *data = (const char *)addr;
63 sigpipe = sigismember(¤t->pending.signal, SIGPIPE);
65 mutex_lock(&sbi->pipe_mutex);
67 wr = __kernel_write(file, data, bytes, &file->f_pos);
73 mutex_unlock(&sbi->pipe_mutex);
75 /* Keep the currently executing process from receiving a
76 * SIGPIPE unless it was already supposed to get one
78 if (wr == -EPIPE && !sigpipe) {
79 spin_lock_irqsave(¤t->sighand->siglock, flags);
80 sigdelset(¤t->pending.signal, SIGPIPE);
82 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
85 /* if 'wr' returned 0 (impossible) we assume -EIO (safe) */
86 return bytes == 0 ? 0 : wr < 0 ? wr : -EIO;
89 static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
90 struct autofs_wait_queue *wq,
94 struct autofs_packet_hdr hdr;
95 union autofs_packet_union v4_pkt;
96 union autofs_v5_packet_union v5_pkt;
98 struct file *pipe = NULL;
102 pr_debug("wait id = 0x%08lx, name = %.*s, type=%d\n",
103 (unsigned long) wq->wait_queue_token,
104 wq->name.len, wq->name.name, type);
106 memset(&pkt, 0, sizeof(pkt)); /* For security reasons */
108 pkt.hdr.proto_version = sbi->version;
112 /* Kernel protocol v4 missing and expire packets */
113 case autofs_ptype_missing:
115 struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
119 mp->wait_queue_token = wq->wait_queue_token;
120 mp->len = wq->name.len;
121 memcpy(mp->name, wq->name.name, wq->name.len);
122 mp->name[wq->name.len] = '\0';
125 case autofs_ptype_expire_multi:
127 struct autofs_packet_expire_multi *ep =
128 &pkt.v4_pkt.expire_multi;
132 ep->wait_queue_token = wq->wait_queue_token;
133 ep->len = wq->name.len;
134 memcpy(ep->name, wq->name.name, wq->name.len);
135 ep->name[wq->name.len] = '\0';
139 * Kernel protocol v5 packet for handling indirect and direct
140 * mount missing and expire requests
142 case autofs_ptype_missing_indirect:
143 case autofs_ptype_expire_indirect:
144 case autofs_ptype_missing_direct:
145 case autofs_ptype_expire_direct:
147 struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
148 struct user_namespace *user_ns = sbi->pipe->f_cred->user_ns;
150 pktsz = sizeof(*packet);
152 packet->wait_queue_token = wq->wait_queue_token;
153 packet->len = wq->name.len;
154 memcpy(packet->name, wq->name.name, wq->name.len);
155 packet->name[wq->name.len] = '\0';
156 packet->dev = wq->dev;
157 packet->ino = wq->ino;
158 packet->uid = from_kuid_munged(user_ns, wq->uid);
159 packet->gid = from_kgid_munged(user_ns, wq->gid);
160 packet->pid = wq->pid;
161 packet->tgid = wq->tgid;
165 pr_warn("bad type %d!\n", type);
166 mutex_unlock(&sbi->wq_mutex);
170 pipe = get_file(sbi->pipe);
172 mutex_unlock(&sbi->wq_mutex);
174 switch (ret = autofs4_write(sbi, pipe, &pkt, pktsz)) {
179 /* Just fail this one */
180 autofs4_wait_release(sbi, wq->wait_queue_token, ret);
183 autofs4_catatonic_mode(sbi);
189 static int autofs4_getpath(struct autofs_sb_info *sbi,
190 struct dentry *dentry, char **name)
192 struct dentry *root = sbi->sb->s_root;
203 seq = read_seqbegin(&rename_lock);
205 spin_lock(&sbi->fs_lock);
206 for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
207 len += tmp->d_name.len + 1;
209 if (!len || --len > NAME_MAX) {
210 spin_unlock(&sbi->fs_lock);
212 if (read_seqretry(&rename_lock, seq))
218 p = buf + len - dentry->d_name.len;
219 strncpy(p, dentry->d_name.name, dentry->d_name.len);
221 for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
223 p -= tmp->d_name.len;
224 strncpy(p, tmp->d_name.name, tmp->d_name.len);
226 spin_unlock(&sbi->fs_lock);
228 if (read_seqretry(&rename_lock, seq))
234 static struct autofs_wait_queue *
235 autofs4_find_wait(struct autofs_sb_info *sbi, const struct qstr *qstr)
237 struct autofs_wait_queue *wq;
239 for (wq = sbi->queues; wq; wq = wq->next) {
240 if (wq->name.hash == qstr->hash &&
241 wq->name.len == qstr->len &&
243 !memcmp(wq->name.name, qstr->name, qstr->len))
250 * Check if we have a valid request.
252 * 1 if the request should continue.
253 * In this case we can return an autofs_wait_queue entry if one is
254 * found or NULL to idicate a new wait needs to be created.
255 * 0 or a negative errno if the request shouldn't continue.
257 static int validate_request(struct autofs_wait_queue **wait,
258 struct autofs_sb_info *sbi,
259 const struct qstr *qstr,
260 const struct path *path, enum autofs_notify notify)
262 struct dentry *dentry = path->dentry;
263 struct autofs_wait_queue *wq;
264 struct autofs_info *ino;
269 /* Wait in progress, continue; */
270 wq = autofs4_find_wait(sbi, qstr);
278 /* If we don't yet have any info this is a new request */
279 ino = autofs4_dentry_ino(dentry);
284 * If we've been asked to wait on an existing expire (NFY_NONE)
285 * but there is no wait in the queue ...
287 if (notify == NFY_NONE) {
289 * Either we've betean the pending expire to post it's
290 * wait or it finished while we waited on the mutex.
291 * So we need to wait till either, the wait appears
292 * or the expire finishes.
295 while (ino->flags & AUTOFS_INF_EXPIRING) {
296 mutex_unlock(&sbi->wq_mutex);
297 schedule_timeout_interruptible(HZ/10);
298 if (mutex_lock_interruptible(&sbi->wq_mutex))
304 wq = autofs4_find_wait(sbi, qstr);
312 * Not ideal but the status has already gone. Of the two
313 * cases where we wait on NFY_NONE neither depend on the
314 * return status of the wait.
320 * If we've been asked to trigger a mount and the request
321 * completed while we waited on the mutex ...
323 if (notify == NFY_MOUNT) {
324 struct dentry *new = NULL;
329 * If the dentry was successfully mounted while we slept
330 * on the wait queue mutex we can return success. If it
331 * isn't mounted (doesn't have submounts for the case of
332 * a multi-mount with no mount at it's base) we can
333 * continue on and create a new request.
335 if (!IS_ROOT(dentry)) {
336 if (d_unhashed(dentry) &&
337 d_really_is_positive(dentry)) {
338 struct dentry *parent = dentry->d_parent;
340 new = d_lookup(parent, &dentry->d_name);
345 this.mnt = path->mnt;
346 this.dentry = dentry;
347 if (path_has_submounts(&this))
358 int autofs4_wait(struct autofs_sb_info *sbi,
359 const struct path *path, enum autofs_notify notify)
361 struct dentry *dentry = path->dentry;
362 struct autofs_wait_queue *wq;
365 int status, ret, type;
369 /* In catatonic mode, we don't wait for nobody */
374 * Try translating pids to the namespace of the daemon.
376 * Zero means failure: we are in an unrelated pid namespace.
378 pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
379 tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
380 if (pid == 0 || tgid == 0)
383 if (d_really_is_negative(dentry)) {
385 * A wait for a negative dentry is invalid for certain
386 * cases. A direct or offset mount "always" has its mount
387 * point directory created and so the request dentry must
388 * be positive or the map key doesn't exist. The situation
389 * is very similar for indirect mounts except only dentrys
390 * in the root of the autofs file system may be negative.
392 if (autofs_type_trigger(sbi->type))
394 else if (!IS_ROOT(dentry->d_parent))
398 name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
402 /* If this is a direct mount request create a dummy name */
403 if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
404 qstr.len = sprintf(name, "%p", dentry);
406 qstr.len = autofs4_getpath(sbi, dentry, &name);
413 qstr.hash = full_name_hash(dentry, name, qstr.len);
415 if (mutex_lock_interruptible(&sbi->wq_mutex)) {
420 ret = validate_request(&wq, sbi, &qstr, path, notify);
423 mutex_unlock(&sbi->wq_mutex);
429 /* Create a new wait queue */
430 wq = kmalloc(sizeof(struct autofs_wait_queue), GFP_KERNEL);
433 mutex_unlock(&sbi->wq_mutex);
437 wq->wait_queue_token = autofs4_next_wait_queue;
438 if (++autofs4_next_wait_queue == 0)
439 autofs4_next_wait_queue = 1;
440 wq->next = sbi->queues;
442 init_waitqueue_head(&wq->queue);
443 memcpy(&wq->name, &qstr, sizeof(struct qstr));
444 wq->dev = autofs4_get_dev(sbi);
445 wq->ino = autofs4_get_ino(sbi);
446 wq->uid = current_cred()->uid;
447 wq->gid = current_cred()->gid;
450 wq->status = -EINTR; /* Status return if interrupted */
453 if (sbi->version < 5) {
454 if (notify == NFY_MOUNT)
455 type = autofs_ptype_missing;
457 type = autofs_ptype_expire_multi;
459 if (notify == NFY_MOUNT)
460 type = autofs_type_trigger(sbi->type) ?
461 autofs_ptype_missing_direct :
462 autofs_ptype_missing_indirect;
464 type = autofs_type_trigger(sbi->type) ?
465 autofs_ptype_expire_direct :
466 autofs_ptype_expire_indirect;
469 pr_debug("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
470 (unsigned long) wq->wait_queue_token, wq->name.len,
471 wq->name.name, notify);
474 * autofs4_notify_daemon() may block; it will unlock ->wq_mutex
476 autofs4_notify_daemon(sbi, wq, type);
479 pr_debug("existing wait id = 0x%08lx, name = %.*s, nfy=%d\n",
480 (unsigned long) wq->wait_queue_token, wq->name.len,
481 wq->name.name, notify);
482 mutex_unlock(&sbi->wq_mutex);
487 * wq->name.name is NULL iff the lock is already released
488 * or the mount has been made catatonic.
491 /* Block all but "shutdown" signals while waiting */
492 unsigned long shutdown_sigs_mask;
493 unsigned long irqflags;
496 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
497 oldset = current->blocked;
498 shutdown_sigs_mask = SHUTDOWN_SIGS & ~oldset.sig[0];
499 siginitsetinv(¤t->blocked, shutdown_sigs_mask);
501 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
503 wait_event_interruptible(wq->queue, wq->name.name == NULL);
505 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
506 current->blocked = oldset;
508 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
510 pr_debug("skipped sleeping\n");
516 * For direct and offset mounts we need to track the requester's
517 * uid and gid in the dentry info struct. This is so it can be
518 * supplied, on request, by the misc device ioctl interface.
519 * This is needed during daemon resatart when reconnecting
520 * to existing, active, autofs mounts. The uid and gid (and
521 * related string values) may be used for macro substitution
522 * in autofs mount maps.
525 struct autofs_info *ino;
526 struct dentry *de = NULL;
528 /* direct mount or browsable map */
529 ino = autofs4_dentry_ino(dentry);
531 /* If not lookup actual dentry used */
532 de = d_lookup(dentry->d_parent, &dentry->d_name);
534 ino = autofs4_dentry_ino(de);
537 /* Set mount requester */
539 spin_lock(&sbi->fs_lock);
542 spin_unlock(&sbi->fs_lock);
549 /* Are we the last process to need status? */
550 mutex_lock(&sbi->wq_mutex);
553 mutex_unlock(&sbi->wq_mutex);
559 int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
561 struct autofs_wait_queue *wq, **wql;
563 mutex_lock(&sbi->wq_mutex);
564 for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
565 if (wq->wait_queue_token == wait_queue_token)
570 mutex_unlock(&sbi->wq_mutex);
574 *wql = wq->next; /* Unlink from chain */
575 kfree(wq->name.name);
576 wq->name.name = NULL; /* Do not wait on this queue */
578 wake_up_interruptible(&wq->queue);
581 mutex_unlock(&sbi->wq_mutex);