freebsd-dev/sys/fs/autofs/autofs.c
Warner Losh fbbd9655e5 Renumber copyright clause 4
Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by:	Jan Schaumann <jschauma@stevens.edu>
Pull Request:	https://github.com/freebsd/freebsd/pull/96
2017-02-28 23:42:47 +00:00

706 lines
19 KiB
C

/*-
* Copyright (c) 2014 The FreeBSD Foundation
* All rights reserved.
*
* This software was developed by Edward Tomasz Napierala under sponsorship
* from the FreeBSD Foundation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
/*-
* Copyright (c) 1989, 1991, 1993, 1995
* The Regents of the University of California. All rights reserved.
*
* This code is derived from software contributed to Berkeley by
* Rick Macklem at The University of Guelph.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/buf.h>
#include <sys/conf.h>
#include <sys/dirent.h>
#include <sys/ioccom.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <sys/mount.h>
#include <sys/refcount.h>
#include <sys/sx.h>
#include <sys/sysctl.h>
#include <sys/syscallsubr.h>
#include <sys/taskqueue.h>
#include <sys/tree.h>
#include <sys/vnode.h>
#include <machine/atomic.h>
#include <vm/uma.h>
#include <fs/autofs/autofs.h>
#include <fs/autofs/autofs_ioctl.h>
MALLOC_DEFINE(M_AUTOFS, "autofs", "Automounter filesystem");
uma_zone_t autofs_request_zone;
uma_zone_t autofs_node_zone;
static int autofs_open(struct cdev *dev, int flags, int fmt,
struct thread *td);
static int autofs_close(struct cdev *dev, int flag, int fmt,
struct thread *td);
static int autofs_ioctl(struct cdev *dev, u_long cmd, caddr_t arg,
int mode, struct thread *td);
static struct cdevsw autofs_cdevsw = {
.d_version = D_VERSION,
.d_open = autofs_open,
.d_close = autofs_close,
.d_ioctl = autofs_ioctl,
.d_name = "autofs",
};
/*
* List of signals that can interrupt an autofs trigger. Might be a good
* idea to keep it synchronised with list in sys/fs/nfs/nfs_commonkrpc.c.
*/
int autofs_sig_set[] = {
SIGINT,
SIGTERM,
SIGHUP,
SIGKILL,
SIGQUIT
};
struct autofs_softc *autofs_softc;
SYSCTL_NODE(_vfs, OID_AUTO, autofs, CTLFLAG_RD, 0, "Automounter filesystem");
int autofs_debug = 1;
TUNABLE_INT("vfs.autofs.debug", &autofs_debug);
SYSCTL_INT(_vfs_autofs, OID_AUTO, debug, CTLFLAG_RWTUN,
&autofs_debug, 1, "Enable debug messages");
int autofs_mount_on_stat = 0;
TUNABLE_INT("vfs.autofs.mount_on_stat", &autofs_mount_on_stat);
SYSCTL_INT(_vfs_autofs, OID_AUTO, mount_on_stat, CTLFLAG_RWTUN,
&autofs_mount_on_stat, 0, "Trigger mount on stat(2) on mountpoint");
int autofs_timeout = 30;
TUNABLE_INT("vfs.autofs.timeout", &autofs_timeout);
SYSCTL_INT(_vfs_autofs, OID_AUTO, timeout, CTLFLAG_RWTUN,
&autofs_timeout, 30, "Number of seconds to wait for automountd(8)");
int autofs_cache = 600;
TUNABLE_INT("vfs.autofs.cache", &autofs_cache);
SYSCTL_INT(_vfs_autofs, OID_AUTO, cache, CTLFLAG_RWTUN,
&autofs_cache, 600, "Number of seconds to wait before reinvoking "
"automountd(8) for any given file or directory");
int autofs_retry_attempts = 3;
TUNABLE_INT("vfs.autofs.retry_attempts", &autofs_retry_attempts);
SYSCTL_INT(_vfs_autofs, OID_AUTO, retry_attempts, CTLFLAG_RWTUN,
&autofs_retry_attempts, 3, "Number of attempts before failing mount");
int autofs_retry_delay = 1;
TUNABLE_INT("vfs.autofs.retry_delay", &autofs_retry_delay);
SYSCTL_INT(_vfs_autofs, OID_AUTO, retry_delay, CTLFLAG_RWTUN,
&autofs_retry_delay, 1, "Number of seconds before retrying");
int autofs_interruptible = 1;
TUNABLE_INT("vfs.autofs.interruptible", &autofs_interruptible);
SYSCTL_INT(_vfs_autofs, OID_AUTO, interruptible, CTLFLAG_RWTUN,
&autofs_interruptible, 1, "Allow requests to be interrupted by signal");
static int
autofs_node_cmp(const struct autofs_node *a, const struct autofs_node *b)
{
return (strcmp(a->an_name, b->an_name));
}
RB_GENERATE(autofs_node_tree, autofs_node, an_link, autofs_node_cmp);
int
autofs_init(struct vfsconf *vfsp)
{
int error;
KASSERT(autofs_softc == NULL,
("softc %p, should be NULL", autofs_softc));
autofs_softc = malloc(sizeof(*autofs_softc), M_AUTOFS,
M_WAITOK | M_ZERO);
autofs_request_zone = uma_zcreate("autofs_request",
sizeof(struct autofs_request), NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, 0);
autofs_node_zone = uma_zcreate("autofs_node",
sizeof(struct autofs_node), NULL, NULL, NULL, NULL,
UMA_ALIGN_PTR, 0);
TAILQ_INIT(&autofs_softc->sc_requests);
cv_init(&autofs_softc->sc_cv, "autofscv");
sx_init(&autofs_softc->sc_lock, "autofslk");
error = make_dev_p(MAKEDEV_CHECKNAME, &autofs_softc->sc_cdev,
&autofs_cdevsw, NULL, UID_ROOT, GID_WHEEL, 0600, "autofs");
if (error != 0) {
AUTOFS_WARN("failed to create device node, error %d", error);
uma_zdestroy(autofs_request_zone);
uma_zdestroy(autofs_node_zone);
free(autofs_softc, M_AUTOFS);
return (error);
}
autofs_softc->sc_cdev->si_drv1 = autofs_softc;
return (0);
}
int
autofs_uninit(struct vfsconf *vfsp)
{
sx_xlock(&autofs_softc->sc_lock);
if (autofs_softc->sc_dev_opened) {
sx_xunlock(&autofs_softc->sc_lock);
return (EBUSY);
}
if (autofs_softc->sc_cdev != NULL)
destroy_dev(autofs_softc->sc_cdev);
uma_zdestroy(autofs_request_zone);
uma_zdestroy(autofs_node_zone);
sx_xunlock(&autofs_softc->sc_lock);
/*
* XXX: Race with open?
*/
free(autofs_softc, M_AUTOFS);
return (0);
}
bool
autofs_ignore_thread(const struct thread *td)
{
struct proc *p;
p = td->td_proc;
if (autofs_softc->sc_dev_opened == false)
return (false);
PROC_LOCK(p);
if (p->p_session->s_sid == autofs_softc->sc_dev_sid) {
PROC_UNLOCK(p);
return (true);
}
PROC_UNLOCK(p);
return (false);
}
static char *
autofs_path(struct autofs_node *anp)
{
struct autofs_mount *amp;
char *path, *tmp;
amp = anp->an_mount;
path = strdup("", M_AUTOFS);
for (; anp->an_parent != NULL; anp = anp->an_parent) {
tmp = malloc(strlen(anp->an_name) + strlen(path) + 2,
M_AUTOFS, M_WAITOK);
strcpy(tmp, anp->an_name);
strcat(tmp, "/");
strcat(tmp, path);
free(path, M_AUTOFS);
path = tmp;
}
tmp = malloc(strlen(amp->am_mountpoint) + strlen(path) + 2,
M_AUTOFS, M_WAITOK);
strcpy(tmp, amp->am_mountpoint);
strcat(tmp, "/");
strcat(tmp, path);
free(path, M_AUTOFS);
path = tmp;
return (path);
}
static void
autofs_task(void *context, int pending)
{
struct autofs_request *ar;
ar = context;
sx_xlock(&autofs_softc->sc_lock);
AUTOFS_WARN("request %d for %s timed out after %d seconds",
ar->ar_id, ar->ar_path, autofs_timeout);
/*
* XXX: EIO perhaps?
*/
ar->ar_error = ETIMEDOUT;
ar->ar_wildcards = true;
ar->ar_done = true;
ar->ar_in_progress = false;
cv_broadcast(&autofs_softc->sc_cv);
sx_xunlock(&autofs_softc->sc_lock);
}
bool
autofs_cached(struct autofs_node *anp, const char *component, int componentlen)
{
int error;
struct autofs_mount *amp;
amp = anp->an_mount;
AUTOFS_ASSERT_UNLOCKED(amp);
/*
* For root node we need to request automountd(8) assistance even
* if the node is marked as cached, but the requested top-level
* directory does not exist. This is necessary for wildcard indirect
* map keys to work. We don't do this if we know that there are
* no wildcards.
*/
if (anp->an_parent == NULL && componentlen != 0 && anp->an_wildcards) {
AUTOFS_SLOCK(amp);
error = autofs_node_find(anp, component, componentlen, NULL);
AUTOFS_SUNLOCK(amp);
if (error != 0)
return (false);
}
return (anp->an_cached);
}
static void
autofs_cache_callout(void *context)
{
struct autofs_node *anp;
anp = context;
anp->an_cached = false;
}
void
autofs_flush(struct autofs_mount *amp)
{
/*
* XXX: This will do for now, but ideally we should iterate
* over all the nodes.
*/
amp->am_root->an_cached = false;
AUTOFS_DEBUG("%s flushed", amp->am_mountpoint);
}
/*
* The set/restore sigmask functions are used to (temporarily) overwrite
* the thread td_sigmask during triggering.
*/
static void
autofs_set_sigmask(sigset_t *oldset)
{
sigset_t newset;
int i;
SIGFILLSET(newset);
/* Remove the autofs set of signals from newset */
PROC_LOCK(curproc);
mtx_lock(&curproc->p_sigacts->ps_mtx);
for (i = 0 ; i < nitems(autofs_sig_set); i++) {
/*
* But make sure we leave the ones already masked
* by the process, i.e. remove the signal from the
* temporary signalmask only if it wasn't already
* in p_sigmask.
*/
if (!SIGISMEMBER(curthread->td_sigmask, autofs_sig_set[i]) &&
!SIGISMEMBER(curproc->p_sigacts->ps_sigignore,
autofs_sig_set[i])) {
SIGDELSET(newset, autofs_sig_set[i]);
}
}
mtx_unlock(&curproc->p_sigacts->ps_mtx);
kern_sigprocmask(curthread, SIG_SETMASK, &newset, oldset,
SIGPROCMASK_PROC_LOCKED);
PROC_UNLOCK(curproc);
}
static void
autofs_restore_sigmask(sigset_t *set)
{
kern_sigprocmask(curthread, SIG_SETMASK, set, NULL, 0);
}
static int
autofs_trigger_one(struct autofs_node *anp,
const char *component, int componentlen)
{
sigset_t oldset;
struct autofs_mount *amp;
struct autofs_node *firstanp;
struct autofs_request *ar;
char *key, *path;
int error = 0, request_error, last;
bool wildcards;
amp = anp->an_mount;
sx_assert(&autofs_softc->sc_lock, SA_XLOCKED);
if (anp->an_parent == NULL) {
key = strndup(component, componentlen, M_AUTOFS);
} else {
for (firstanp = anp; firstanp->an_parent->an_parent != NULL;
firstanp = firstanp->an_parent)
continue;
key = strdup(firstanp->an_name, M_AUTOFS);
}
path = autofs_path(anp);
TAILQ_FOREACH(ar, &autofs_softc->sc_requests, ar_next) {
if (strcmp(ar->ar_path, path) != 0)
continue;
if (strcmp(ar->ar_key, key) != 0)
continue;
KASSERT(strcmp(ar->ar_from, amp->am_from) == 0,
("from changed; %s != %s", ar->ar_from, amp->am_from));
KASSERT(strcmp(ar->ar_prefix, amp->am_prefix) == 0,
("prefix changed; %s != %s",
ar->ar_prefix, amp->am_prefix));
KASSERT(strcmp(ar->ar_options, amp->am_options) == 0,
("options changed; %s != %s",
ar->ar_options, amp->am_options));
break;
}
if (ar != NULL) {
refcount_acquire(&ar->ar_refcount);
} else {
ar = uma_zalloc(autofs_request_zone, M_WAITOK | M_ZERO);
ar->ar_mount = amp;
ar->ar_id =
atomic_fetchadd_int(&autofs_softc->sc_last_request_id, 1);
strlcpy(ar->ar_from, amp->am_from, sizeof(ar->ar_from));
strlcpy(ar->ar_path, path, sizeof(ar->ar_path));
strlcpy(ar->ar_prefix, amp->am_prefix, sizeof(ar->ar_prefix));
strlcpy(ar->ar_key, key, sizeof(ar->ar_key));
strlcpy(ar->ar_options,
amp->am_options, sizeof(ar->ar_options));
TIMEOUT_TASK_INIT(taskqueue_thread, &ar->ar_task, 0,
autofs_task, ar);
taskqueue_enqueue_timeout(taskqueue_thread, &ar->ar_task,
autofs_timeout * hz);
refcount_init(&ar->ar_refcount, 1);
TAILQ_INSERT_TAIL(&autofs_softc->sc_requests, ar, ar_next);
}
cv_broadcast(&autofs_softc->sc_cv);
while (ar->ar_done == false) {
if (autofs_interruptible != 0) {
autofs_set_sigmask(&oldset);
error = cv_wait_sig(&autofs_softc->sc_cv,
&autofs_softc->sc_lock);
autofs_restore_sigmask(&oldset);
if (error != 0) {
AUTOFS_WARN("cv_wait_sig for %s failed "
"with error %d", ar->ar_path, error);
break;
}
} else {
cv_wait(&autofs_softc->sc_cv, &autofs_softc->sc_lock);
}
}
request_error = ar->ar_error;
if (request_error != 0) {
AUTOFS_WARN("request for %s completed with error %d",
ar->ar_path, request_error);
}
wildcards = ar->ar_wildcards;
last = refcount_release(&ar->ar_refcount);
if (last) {
TAILQ_REMOVE(&autofs_softc->sc_requests, ar, ar_next);
/*
* Unlock the sc_lock, so that autofs_task() can complete.
*/
sx_xunlock(&autofs_softc->sc_lock);
taskqueue_cancel_timeout(taskqueue_thread, &ar->ar_task, NULL);
taskqueue_drain_timeout(taskqueue_thread, &ar->ar_task);
uma_zfree(autofs_request_zone, ar);
sx_xlock(&autofs_softc->sc_lock);
}
/*
* Note that we do not do negative caching on purpose. This
* way the user can retry access at any time, e.g. after fixing
* the failure reason, without waiting for cache timer to expire.
*/
if (error == 0 && request_error == 0 && autofs_cache > 0) {
anp->an_cached = true;
anp->an_wildcards = wildcards;
callout_reset(&anp->an_callout, autofs_cache * hz,
autofs_cache_callout, anp);
}
free(key, M_AUTOFS);
free(path, M_AUTOFS);
if (error != 0)
return (error);
return (request_error);
}
/*
* Send request to automountd(8) and wait for completion.
*/
int
autofs_trigger(struct autofs_node *anp,
const char *component, int componentlen)
{
int error;
for (;;) {
error = autofs_trigger_one(anp, component, componentlen);
if (error == 0) {
anp->an_retries = 0;
return (0);
}
if (error == EINTR || error == ERESTART) {
AUTOFS_DEBUG("trigger interrupted by signal, "
"not retrying");
anp->an_retries = 0;
return (error);
}
anp->an_retries++;
if (anp->an_retries >= autofs_retry_attempts) {
AUTOFS_DEBUG("trigger failed %d times; returning "
"error %d", anp->an_retries, error);
anp->an_retries = 0;
return (error);
}
AUTOFS_DEBUG("trigger failed with error %d; will retry in "
"%d seconds, %d attempts left", error, autofs_retry_delay,
autofs_retry_attempts - anp->an_retries);
sx_xunlock(&autofs_softc->sc_lock);
pause("autofs_retry", autofs_retry_delay * hz);
sx_xlock(&autofs_softc->sc_lock);
}
}
static int
autofs_ioctl_request(struct autofs_daemon_request *adr)
{
struct autofs_request *ar;
int error;
sx_xlock(&autofs_softc->sc_lock);
for (;;) {
TAILQ_FOREACH(ar, &autofs_softc->sc_requests, ar_next) {
if (ar->ar_done)
continue;
if (ar->ar_in_progress)
continue;
break;
}
if (ar != NULL)
break;
error = cv_wait_sig(&autofs_softc->sc_cv,
&autofs_softc->sc_lock);
if (error != 0) {
sx_xunlock(&autofs_softc->sc_lock);
return (error);
}
}
ar->ar_in_progress = true;
sx_xunlock(&autofs_softc->sc_lock);
adr->adr_id = ar->ar_id;
strlcpy(adr->adr_from, ar->ar_from, sizeof(adr->adr_from));
strlcpy(adr->adr_path, ar->ar_path, sizeof(adr->adr_path));
strlcpy(adr->adr_prefix, ar->ar_prefix, sizeof(adr->adr_prefix));
strlcpy(adr->adr_key, ar->ar_key, sizeof(adr->adr_key));
strlcpy(adr->adr_options, ar->ar_options, sizeof(adr->adr_options));
PROC_LOCK(curproc);
autofs_softc->sc_dev_sid = curproc->p_session->s_sid;
PROC_UNLOCK(curproc);
return (0);
}
static int
autofs_ioctl_done_101(struct autofs_daemon_done_101 *add)
{
struct autofs_request *ar;
sx_xlock(&autofs_softc->sc_lock);
TAILQ_FOREACH(ar, &autofs_softc->sc_requests, ar_next) {
if (ar->ar_id == add->add_id)
break;
}
if (ar == NULL) {
sx_xunlock(&autofs_softc->sc_lock);
AUTOFS_DEBUG("id %d not found", add->add_id);
return (ESRCH);
}
ar->ar_error = add->add_error;
ar->ar_wildcards = true;
ar->ar_done = true;
ar->ar_in_progress = false;
cv_broadcast(&autofs_softc->sc_cv);
sx_xunlock(&autofs_softc->sc_lock);
return (0);
}
static int
autofs_ioctl_done(struct autofs_daemon_done *add)
{
struct autofs_request *ar;
sx_xlock(&autofs_softc->sc_lock);
TAILQ_FOREACH(ar, &autofs_softc->sc_requests, ar_next) {
if (ar->ar_id == add->add_id)
break;
}
if (ar == NULL) {
sx_xunlock(&autofs_softc->sc_lock);
AUTOFS_DEBUG("id %d not found", add->add_id);
return (ESRCH);
}
ar->ar_error = add->add_error;
ar->ar_wildcards = add->add_wildcards;
ar->ar_done = true;
ar->ar_in_progress = false;
cv_broadcast(&autofs_softc->sc_cv);
sx_xunlock(&autofs_softc->sc_lock);
return (0);
}
static int
autofs_open(struct cdev *dev, int flags, int fmt, struct thread *td)
{
sx_xlock(&autofs_softc->sc_lock);
/*
* We must never block automountd(8) and its descendants, and we use
* session ID to determine that: we store session id of the process
* that opened the device, and then compare it with session ids
* of triggering processes. This means running a second automountd(8)
* instance would break the previous one. The check below prevents
* it from happening.
*/
if (autofs_softc->sc_dev_opened) {
sx_xunlock(&autofs_softc->sc_lock);
return (EBUSY);
}
autofs_softc->sc_dev_opened = true;
sx_xunlock(&autofs_softc->sc_lock);
return (0);
}
static int
autofs_close(struct cdev *dev, int flag, int fmt, struct thread *td)
{
sx_xlock(&autofs_softc->sc_lock);
KASSERT(autofs_softc->sc_dev_opened, ("not opened?"));
autofs_softc->sc_dev_opened = false;
sx_xunlock(&autofs_softc->sc_lock);
return (0);
}
static int
autofs_ioctl(struct cdev *dev, u_long cmd, caddr_t arg, int mode,
struct thread *td)
{
KASSERT(autofs_softc->sc_dev_opened, ("not opened?"));
switch (cmd) {
case AUTOFSREQUEST:
return (autofs_ioctl_request(
(struct autofs_daemon_request *)arg));
case AUTOFSDONE101:
return (autofs_ioctl_done_101(
(struct autofs_daemon_done_101 *)arg));
case AUTOFSDONE:
return (autofs_ioctl_done(
(struct autofs_daemon_done *)arg));
default:
AUTOFS_DEBUG("invalid cmd %lx", cmd);
return (EINVAL);
}
}