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 void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
24 struct autofs_wait_queue *wq, *nwq;
26 mutex_lock(&sbi->wq_mutex);
28 mutex_unlock(&sbi->wq_mutex);
32 pr_debug("entering catatonic mode\n");
36 sbi->queues = NULL; /* Erase all wait queues */
39 wq->status = -ENOENT; /* Magic is gone - report failure */
43 wake_up_interruptible(&wq->queue);
46 fput(sbi->pipe); /* Close the pipe */
49 mutex_unlock(&sbi->wq_mutex);
52 static int autofs4_write(struct autofs_sb_info *sbi,
53 struct file *file, const void *addr, int bytes)
55 unsigned long sigpipe, flags;
56 const char *data = (const char *)addr;
59 sigpipe = sigismember(¤t->pending.signal, SIGPIPE);
61 mutex_lock(&sbi->pipe_mutex);
63 wr = __kernel_write(file, data, bytes, &file->f_pos);
69 mutex_unlock(&sbi->pipe_mutex);
71 /* Keep the currently executing process from receiving a
72 * SIGPIPE unless it was already supposed to get one
74 if (wr == -EPIPE && !sigpipe) {
75 spin_lock_irqsave(¤t->sighand->siglock, flags);
76 sigdelset(¤t->pending.signal, SIGPIPE);
78 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
81 /* if 'wr' returned 0 (impossible) we assume -EIO (safe) */
82 return bytes == 0 ? 0 : wr < 0 ? wr : -EIO;
85 static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
86 struct autofs_wait_queue *wq,
90 struct autofs_packet_hdr hdr;
91 union autofs_packet_union v4_pkt;
92 union autofs_v5_packet_union v5_pkt;
94 struct file *pipe = NULL;
98 pr_debug("wait id = 0x%08lx, name = %.*s, type=%d\n",
99 (unsigned long) wq->wait_queue_token,
100 wq->name.len, wq->name.name, type);
102 memset(&pkt, 0, sizeof(pkt)); /* For security reasons */
104 pkt.hdr.proto_version = sbi->version;
108 /* Kernel protocol v4 missing and expire packets */
109 case autofs_ptype_missing:
111 struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
115 mp->wait_queue_token = wq->wait_queue_token;
116 mp->len = wq->name.len;
117 memcpy(mp->name, wq->name.name, wq->name.len);
118 mp->name[wq->name.len] = '\0';
121 case autofs_ptype_expire_multi:
123 struct autofs_packet_expire_multi *ep =
124 &pkt.v4_pkt.expire_multi;
128 ep->wait_queue_token = wq->wait_queue_token;
129 ep->len = wq->name.len;
130 memcpy(ep->name, wq->name.name, wq->name.len);
131 ep->name[wq->name.len] = '\0';
135 * Kernel protocol v5 packet for handling indirect and direct
136 * mount missing and expire requests
138 case autofs_ptype_missing_indirect:
139 case autofs_ptype_expire_indirect:
140 case autofs_ptype_missing_direct:
141 case autofs_ptype_expire_direct:
143 struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
144 struct user_namespace *user_ns = sbi->pipe->f_cred->user_ns;
146 pktsz = sizeof(*packet);
148 packet->wait_queue_token = wq->wait_queue_token;
149 packet->len = wq->name.len;
150 memcpy(packet->name, wq->name.name, wq->name.len);
151 packet->name[wq->name.len] = '\0';
152 packet->dev = wq->dev;
153 packet->ino = wq->ino;
154 packet->uid = from_kuid_munged(user_ns, wq->uid);
155 packet->gid = from_kgid_munged(user_ns, wq->gid);
156 packet->pid = wq->pid;
157 packet->tgid = wq->tgid;
161 pr_warn("bad type %d!\n", type);
162 mutex_unlock(&sbi->wq_mutex);
166 pipe = get_file(sbi->pipe);
168 mutex_unlock(&sbi->wq_mutex);
170 switch (ret = autofs4_write(sbi, pipe, &pkt, pktsz)) {
175 /* Just fail this one */
176 autofs4_wait_release(sbi, wq->wait_queue_token, ret);
179 autofs4_catatonic_mode(sbi);
185 static int autofs4_getpath(struct autofs_sb_info *sbi,
186 struct dentry *dentry, char **name)
188 struct dentry *root = sbi->sb->s_root;
199 seq = read_seqbegin(&rename_lock);
201 spin_lock(&sbi->fs_lock);
202 for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
203 len += tmp->d_name.len + 1;
205 if (!len || --len > NAME_MAX) {
206 spin_unlock(&sbi->fs_lock);
208 if (read_seqretry(&rename_lock, seq))
214 p = buf + len - dentry->d_name.len;
215 strncpy(p, dentry->d_name.name, dentry->d_name.len);
217 for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
219 p -= tmp->d_name.len;
220 strncpy(p, tmp->d_name.name, tmp->d_name.len);
222 spin_unlock(&sbi->fs_lock);
224 if (read_seqretry(&rename_lock, seq))
230 static struct autofs_wait_queue *
231 autofs4_find_wait(struct autofs_sb_info *sbi, const struct qstr *qstr)
233 struct autofs_wait_queue *wq;
235 for (wq = sbi->queues; wq; wq = wq->next) {
236 if (wq->name.hash == qstr->hash &&
237 wq->name.len == qstr->len &&
239 !memcmp(wq->name.name, qstr->name, qstr->len))
246 * Check if we have a valid request.
248 * 1 if the request should continue.
249 * In this case we can return an autofs_wait_queue entry if one is
250 * found or NULL to idicate a new wait needs to be created.
251 * 0 or a negative errno if the request shouldn't continue.
253 static int validate_request(struct autofs_wait_queue **wait,
254 struct autofs_sb_info *sbi,
255 const struct qstr *qstr,
256 const struct path *path, enum autofs_notify notify)
258 struct dentry *dentry = path->dentry;
259 struct autofs_wait_queue *wq;
260 struct autofs_info *ino;
265 /* Wait in progress, continue; */
266 wq = autofs4_find_wait(sbi, qstr);
274 /* If we don't yet have any info this is a new request */
275 ino = autofs4_dentry_ino(dentry);
280 * If we've been asked to wait on an existing expire (NFY_NONE)
281 * but there is no wait in the queue ...
283 if (notify == NFY_NONE) {
285 * Either we've betean the pending expire to post it's
286 * wait or it finished while we waited on the mutex.
287 * So we need to wait till either, the wait appears
288 * or the expire finishes.
291 while (ino->flags & AUTOFS_INF_EXPIRING) {
292 mutex_unlock(&sbi->wq_mutex);
293 schedule_timeout_interruptible(HZ/10);
294 if (mutex_lock_interruptible(&sbi->wq_mutex))
300 wq = autofs4_find_wait(sbi, qstr);
308 * Not ideal but the status has already gone. Of the two
309 * cases where we wait on NFY_NONE neither depend on the
310 * return status of the wait.
316 * If we've been asked to trigger a mount and the request
317 * completed while we waited on the mutex ...
319 if (notify == NFY_MOUNT) {
320 struct dentry *new = NULL;
325 * If the dentry was successfully mounted while we slept
326 * on the wait queue mutex we can return success. If it
327 * isn't mounted (doesn't have submounts for the case of
328 * a multi-mount with no mount at it's base) we can
329 * continue on and create a new request.
331 if (!IS_ROOT(dentry)) {
332 if (d_unhashed(dentry) &&
333 d_really_is_positive(dentry)) {
334 struct dentry *parent = dentry->d_parent;
336 new = d_lookup(parent, &dentry->d_name);
341 this.mnt = path->mnt;
342 this.dentry = dentry;
343 if (path_has_submounts(&this))
354 int autofs4_wait(struct autofs_sb_info *sbi,
355 const struct path *path, enum autofs_notify notify)
357 struct dentry *dentry = path->dentry;
358 struct autofs_wait_queue *wq;
361 int status, ret, type;
365 /* In catatonic mode, we don't wait for nobody */
370 * Try translating pids to the namespace of the daemon.
372 * Zero means failure: we are in an unrelated pid namespace.
374 pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
375 tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
376 if (pid == 0 || tgid == 0)
379 if (d_really_is_negative(dentry)) {
381 * A wait for a negative dentry is invalid for certain
382 * cases. A direct or offset mount "always" has its mount
383 * point directory created and so the request dentry must
384 * be positive or the map key doesn't exist. The situation
385 * is very similar for indirect mounts except only dentrys
386 * in the root of the autofs file system may be negative.
388 if (autofs_type_trigger(sbi->type))
390 else if (!IS_ROOT(dentry->d_parent))
394 name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
398 /* If this is a direct mount request create a dummy name */
399 if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
400 qstr.len = sprintf(name, "%p", dentry);
402 qstr.len = autofs4_getpath(sbi, dentry, &name);
409 qstr.hash = full_name_hash(dentry, name, qstr.len);
411 if (mutex_lock_interruptible(&sbi->wq_mutex)) {
416 ret = validate_request(&wq, sbi, &qstr, path, notify);
419 mutex_unlock(&sbi->wq_mutex);
425 /* Create a new wait queue */
426 wq = kmalloc(sizeof(struct autofs_wait_queue), GFP_KERNEL);
429 mutex_unlock(&sbi->wq_mutex);
433 wq->wait_queue_token = autofs4_next_wait_queue;
434 if (++autofs4_next_wait_queue == 0)
435 autofs4_next_wait_queue = 1;
436 wq->next = sbi->queues;
438 init_waitqueue_head(&wq->queue);
439 memcpy(&wq->name, &qstr, sizeof(struct qstr));
440 wq->dev = autofs4_get_dev(sbi);
441 wq->ino = autofs4_get_ino(sbi);
442 wq->uid = current_uid();
443 wq->gid = current_gid();
446 wq->status = -EINTR; /* Status return if interrupted */
449 if (sbi->version < 5) {
450 if (notify == NFY_MOUNT)
451 type = autofs_ptype_missing;
453 type = autofs_ptype_expire_multi;
455 if (notify == NFY_MOUNT)
456 type = autofs_type_trigger(sbi->type) ?
457 autofs_ptype_missing_direct :
458 autofs_ptype_missing_indirect;
460 type = autofs_type_trigger(sbi->type) ?
461 autofs_ptype_expire_direct :
462 autofs_ptype_expire_indirect;
465 pr_debug("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
466 (unsigned long) wq->wait_queue_token, wq->name.len,
467 wq->name.name, notify);
470 * autofs4_notify_daemon() may block; it will unlock ->wq_mutex
472 autofs4_notify_daemon(sbi, wq, type);
475 pr_debug("existing wait id = 0x%08lx, name = %.*s, nfy=%d\n",
476 (unsigned long) wq->wait_queue_token, wq->name.len,
477 wq->name.name, notify);
478 mutex_unlock(&sbi->wq_mutex);
483 * wq->name.name is NULL iff the lock is already released
484 * or the mount has been made catatonic.
486 wait_event_killable(wq->queue, wq->name.name == NULL);
490 * For direct and offset mounts we need to track the requester's
491 * uid and gid in the dentry info struct. This is so it can be
492 * supplied, on request, by the misc device ioctl interface.
493 * This is needed during daemon resatart when reconnecting
494 * to existing, active, autofs mounts. The uid and gid (and
495 * related string values) may be used for macro substitution
496 * in autofs mount maps.
499 struct autofs_info *ino;
500 struct dentry *de = NULL;
502 /* direct mount or browsable map */
503 ino = autofs4_dentry_ino(dentry);
505 /* If not lookup actual dentry used */
506 de = d_lookup(dentry->d_parent, &dentry->d_name);
508 ino = autofs4_dentry_ino(de);
511 /* Set mount requester */
513 spin_lock(&sbi->fs_lock);
516 spin_unlock(&sbi->fs_lock);
523 /* Are we the last process to need status? */
524 mutex_lock(&sbi->wq_mutex);
527 mutex_unlock(&sbi->wq_mutex);
533 int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
535 struct autofs_wait_queue *wq, **wql;
537 mutex_lock(&sbi->wq_mutex);
538 for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
539 if (wq->wait_queue_token == wait_queue_token)
544 mutex_unlock(&sbi->wq_mutex);
548 *wql = wq->next; /* Unlink from chain */
549 kfree(wq->name.name);
550 wq->name.name = NULL; /* Do not wait on this queue */
555 mutex_unlock(&sbi->wq_mutex);