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/file.h>
16 /* We make this a static variable rather than a part of the superblock; it
17 * is better if we don't reassign numbers easily even across filesystems
19 static autofs_wqt_t autofs4_next_wait_queue = 1;
21 /* These are the signals we allow interrupting a pending mount */
22 #define SHUTDOWN_SIGS (sigmask(SIGKILL) | sigmask(SIGINT) | sigmask(SIGQUIT))
24 void autofs4_catatonic_mode(struct autofs_sb_info *sbi)
26 struct autofs_wait_queue *wq, *nwq;
28 mutex_lock(&sbi->wq_mutex);
30 mutex_unlock(&sbi->wq_mutex);
34 pr_debug("entering catatonic mode\n");
38 sbi->queues = NULL; /* Erase all wait queues */
41 wq->status = -ENOENT; /* Magic is gone - report failure */
45 wake_up_interruptible(&wq->queue);
48 fput(sbi->pipe); /* Close the pipe */
51 mutex_unlock(&sbi->wq_mutex);
54 static int autofs4_write(struct autofs_sb_info *sbi,
55 struct file *file, const void *addr, int bytes)
57 unsigned long sigpipe, flags;
59 const char *data = (const char *)addr;
62 sigpipe = sigismember(¤t->pending.signal, SIGPIPE);
64 /* Save pointer to user space and point back to kernel space */
68 mutex_lock(&sbi->pipe_mutex);
70 wr = __vfs_write(file, data, bytes, &file->f_pos);
76 mutex_unlock(&sbi->pipe_mutex);
80 /* Keep the currently executing process from receiving a
81 * SIGPIPE unless it was already supposed to get one
83 if (wr == -EPIPE && !sigpipe) {
84 spin_lock_irqsave(¤t->sighand->siglock, flags);
85 sigdelset(¤t->pending.signal, SIGPIPE);
87 spin_unlock_irqrestore(¤t->sighand->siglock, flags);
93 static void autofs4_notify_daemon(struct autofs_sb_info *sbi,
94 struct autofs_wait_queue *wq,
98 struct autofs_packet_hdr hdr;
99 union autofs_packet_union v4_pkt;
100 union autofs_v5_packet_union v5_pkt;
102 struct file *pipe = NULL;
105 pr_debug("wait id = 0x%08lx, name = %.*s, type=%d\n",
106 (unsigned long) wq->wait_queue_token,
107 wq->name.len, wq->name.name, type);
109 memset(&pkt, 0, sizeof(pkt)); /* For security reasons */
111 pkt.hdr.proto_version = sbi->version;
115 /* Kernel protocol v4 missing and expire packets */
116 case autofs_ptype_missing:
118 struct autofs_packet_missing *mp = &pkt.v4_pkt.missing;
122 mp->wait_queue_token = wq->wait_queue_token;
123 mp->len = wq->name.len;
124 memcpy(mp->name, wq->name.name, wq->name.len);
125 mp->name[wq->name.len] = '\0';
128 case autofs_ptype_expire_multi:
130 struct autofs_packet_expire_multi *ep =
131 &pkt.v4_pkt.expire_multi;
135 ep->wait_queue_token = wq->wait_queue_token;
136 ep->len = wq->name.len;
137 memcpy(ep->name, wq->name.name, wq->name.len);
138 ep->name[wq->name.len] = '\0';
142 * Kernel protocol v5 packet for handling indirect and direct
143 * mount missing and expire requests
145 case autofs_ptype_missing_indirect:
146 case autofs_ptype_expire_indirect:
147 case autofs_ptype_missing_direct:
148 case autofs_ptype_expire_direct:
150 struct autofs_v5_packet *packet = &pkt.v5_pkt.v5_packet;
151 struct user_namespace *user_ns = sbi->pipe->f_cred->user_ns;
153 pktsz = sizeof(*packet);
155 packet->wait_queue_token = wq->wait_queue_token;
156 packet->len = wq->name.len;
157 memcpy(packet->name, wq->name.name, wq->name.len);
158 packet->name[wq->name.len] = '\0';
159 packet->dev = wq->dev;
160 packet->ino = wq->ino;
161 packet->uid = from_kuid_munged(user_ns, wq->uid);
162 packet->gid = from_kgid_munged(user_ns, wq->gid);
163 packet->pid = wq->pid;
164 packet->tgid = wq->tgid;
168 pr_warn("bad type %d!\n", type);
169 mutex_unlock(&sbi->wq_mutex);
173 pipe = get_file(sbi->pipe);
175 mutex_unlock(&sbi->wq_mutex);
177 if (autofs4_write(sbi, pipe, &pkt, pktsz))
178 autofs4_catatonic_mode(sbi);
182 static int autofs4_getpath(struct autofs_sb_info *sbi,
183 struct dentry *dentry, char **name)
185 struct dentry *root = sbi->sb->s_root;
196 seq = read_seqbegin(&rename_lock);
198 spin_lock(&sbi->fs_lock);
199 for (tmp = dentry ; tmp != root ; tmp = tmp->d_parent)
200 len += tmp->d_name.len + 1;
202 if (!len || --len > NAME_MAX) {
203 spin_unlock(&sbi->fs_lock);
205 if (read_seqretry(&rename_lock, seq))
211 p = buf + len - dentry->d_name.len;
212 strncpy(p, dentry->d_name.name, dentry->d_name.len);
214 for (tmp = dentry->d_parent; tmp != root ; tmp = tmp->d_parent) {
216 p -= tmp->d_name.len;
217 strncpy(p, tmp->d_name.name, tmp->d_name.len);
219 spin_unlock(&sbi->fs_lock);
221 if (read_seqretry(&rename_lock, seq))
227 static struct autofs_wait_queue *
228 autofs4_find_wait(struct autofs_sb_info *sbi, const struct qstr *qstr)
230 struct autofs_wait_queue *wq;
232 for (wq = sbi->queues; wq; wq = wq->next) {
233 if (wq->name.hash == qstr->hash &&
234 wq->name.len == qstr->len &&
236 !memcmp(wq->name.name, qstr->name, qstr->len))
243 * Check if we have a valid request.
245 * 1 if the request should continue.
246 * In this case we can return an autofs_wait_queue entry if one is
247 * found or NULL to idicate a new wait needs to be created.
248 * 0 or a negative errno if the request shouldn't continue.
250 static int validate_request(struct autofs_wait_queue **wait,
251 struct autofs_sb_info *sbi,
252 const struct qstr *qstr,
253 const struct path *path, enum autofs_notify notify)
255 struct dentry *dentry = path->dentry;
256 struct autofs_wait_queue *wq;
257 struct autofs_info *ino;
262 /* Wait in progress, continue; */
263 wq = autofs4_find_wait(sbi, qstr);
271 /* If we don't yet have any info this is a new request */
272 ino = autofs4_dentry_ino(dentry);
277 * If we've been asked to wait on an existing expire (NFY_NONE)
278 * but there is no wait in the queue ...
280 if (notify == NFY_NONE) {
282 * Either we've betean the pending expire to post it's
283 * wait or it finished while we waited on the mutex.
284 * So we need to wait till either, the wait appears
285 * or the expire finishes.
288 while (ino->flags & AUTOFS_INF_EXPIRING) {
289 mutex_unlock(&sbi->wq_mutex);
290 schedule_timeout_interruptible(HZ/10);
291 if (mutex_lock_interruptible(&sbi->wq_mutex))
297 wq = autofs4_find_wait(sbi, qstr);
305 * Not ideal but the status has already gone. Of the two
306 * cases where we wait on NFY_NONE neither depend on the
307 * return status of the wait.
313 * If we've been asked to trigger a mount and the request
314 * completed while we waited on the mutex ...
316 if (notify == NFY_MOUNT) {
317 struct dentry *new = NULL;
322 * If the dentry was successfully mounted while we slept
323 * on the wait queue mutex we can return success. If it
324 * isn't mounted (doesn't have submounts for the case of
325 * a multi-mount with no mount at it's base) we can
326 * continue on and create a new request.
328 if (!IS_ROOT(dentry)) {
329 if (d_unhashed(dentry) &&
330 d_really_is_positive(dentry)) {
331 struct dentry *parent = dentry->d_parent;
333 new = d_lookup(parent, &dentry->d_name);
338 this.mnt = path->mnt;
339 this.dentry = dentry;
340 if (path_has_submounts(&this))
351 int autofs4_wait(struct autofs_sb_info *sbi,
352 const struct path *path, enum autofs_notify notify)
354 struct dentry *dentry = path->dentry;
355 struct autofs_wait_queue *wq;
358 int status, ret, type;
362 /* In catatonic mode, we don't wait for nobody */
367 * Try translating pids to the namespace of the daemon.
369 * Zero means failure: we are in an unrelated pid namespace.
371 pid = task_pid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
372 tgid = task_tgid_nr_ns(current, ns_of_pid(sbi->oz_pgrp));
373 if (pid == 0 || tgid == 0)
376 if (d_really_is_negative(dentry)) {
378 * A wait for a negative dentry is invalid for certain
379 * cases. A direct or offset mount "always" has its mount
380 * point directory created and so the request dentry must
381 * be positive or the map key doesn't exist. The situation
382 * is very similar for indirect mounts except only dentrys
383 * in the root of the autofs file system may be negative.
385 if (autofs_type_trigger(sbi->type))
387 else if (!IS_ROOT(dentry->d_parent))
391 name = kmalloc(NAME_MAX + 1, GFP_KERNEL);
395 /* If this is a direct mount request create a dummy name */
396 if (IS_ROOT(dentry) && autofs_type_trigger(sbi->type))
397 qstr.len = sprintf(name, "%p", dentry);
399 qstr.len = autofs4_getpath(sbi, dentry, &name);
406 qstr.hash = full_name_hash(dentry, name, qstr.len);
408 if (mutex_lock_interruptible(&sbi->wq_mutex)) {
413 ret = validate_request(&wq, sbi, &qstr, path, notify);
416 mutex_unlock(&sbi->wq_mutex);
422 /* Create a new wait queue */
423 wq = kmalloc(sizeof(struct autofs_wait_queue), GFP_KERNEL);
426 mutex_unlock(&sbi->wq_mutex);
430 wq->wait_queue_token = autofs4_next_wait_queue;
431 if (++autofs4_next_wait_queue == 0)
432 autofs4_next_wait_queue = 1;
433 wq->next = sbi->queues;
435 init_waitqueue_head(&wq->queue);
436 memcpy(&wq->name, &qstr, sizeof(struct qstr));
437 wq->dev = autofs4_get_dev(sbi);
438 wq->ino = autofs4_get_ino(sbi);
439 wq->uid = current_cred()->uid;
440 wq->gid = current_cred()->gid;
443 wq->status = -EINTR; /* Status return if interrupted */
446 if (sbi->version < 5) {
447 if (notify == NFY_MOUNT)
448 type = autofs_ptype_missing;
450 type = autofs_ptype_expire_multi;
452 if (notify == NFY_MOUNT)
453 type = autofs_type_trigger(sbi->type) ?
454 autofs_ptype_missing_direct :
455 autofs_ptype_missing_indirect;
457 type = autofs_type_trigger(sbi->type) ?
458 autofs_ptype_expire_direct :
459 autofs_ptype_expire_indirect;
462 pr_debug("new wait id = 0x%08lx, name = %.*s, nfy=%d\n",
463 (unsigned long) wq->wait_queue_token, wq->name.len,
464 wq->name.name, notify);
467 * autofs4_notify_daemon() may block; it will unlock ->wq_mutex
469 autofs4_notify_daemon(sbi, wq, type);
472 pr_debug("existing wait id = 0x%08lx, name = %.*s, nfy=%d\n",
473 (unsigned long) wq->wait_queue_token, wq->name.len,
474 wq->name.name, notify);
475 mutex_unlock(&sbi->wq_mutex);
480 * wq->name.name is NULL iff the lock is already released
481 * or the mount has been made catatonic.
484 /* Block all but "shutdown" signals while waiting */
485 unsigned long shutdown_sigs_mask;
486 unsigned long irqflags;
489 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
490 oldset = current->blocked;
491 shutdown_sigs_mask = SHUTDOWN_SIGS & ~oldset.sig[0];
492 siginitsetinv(¤t->blocked, shutdown_sigs_mask);
494 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
496 wait_event_interruptible(wq->queue, wq->name.name == NULL);
498 spin_lock_irqsave(¤t->sighand->siglock, irqflags);
499 current->blocked = oldset;
501 spin_unlock_irqrestore(¤t->sighand->siglock, irqflags);
503 pr_debug("skipped sleeping\n");
509 * For direct and offset mounts we need to track the requester's
510 * uid and gid in the dentry info struct. This is so it can be
511 * supplied, on request, by the misc device ioctl interface.
512 * This is needed during daemon resatart when reconnecting
513 * to existing, active, autofs mounts. The uid and gid (and
514 * related string values) may be used for macro substitution
515 * in autofs mount maps.
518 struct autofs_info *ino;
519 struct dentry *de = NULL;
521 /* direct mount or browsable map */
522 ino = autofs4_dentry_ino(dentry);
524 /* If not lookup actual dentry used */
525 de = d_lookup(dentry->d_parent, &dentry->d_name);
527 ino = autofs4_dentry_ino(de);
530 /* Set mount requester */
532 spin_lock(&sbi->fs_lock);
535 spin_unlock(&sbi->fs_lock);
542 /* Are we the last process to need status? */
543 mutex_lock(&sbi->wq_mutex);
546 mutex_unlock(&sbi->wq_mutex);
552 int autofs4_wait_release(struct autofs_sb_info *sbi, autofs_wqt_t wait_queue_token, int status)
554 struct autofs_wait_queue *wq, **wql;
556 mutex_lock(&sbi->wq_mutex);
557 for (wql = &sbi->queues; (wq = *wql) != NULL; wql = &wq->next) {
558 if (wq->wait_queue_token == wait_queue_token)
563 mutex_unlock(&sbi->wq_mutex);
567 *wql = wq->next; /* Unlink from chain */
568 kfree(wq->name.name);
569 wq->name.name = NULL; /* Do not wait on this queue */
571 wake_up_interruptible(&wq->queue);
574 mutex_unlock(&sbi->wq_mutex);