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Systemd/src/core/automount.c

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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <errno.h>
#include <limits.h>
#include <sys/mount.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/epoll.h>
#include <sys/stat.h>
#include <linux/auto_fs4.h>
#include <linux/auto_dev-ioctl.h>
#include "unit.h"
#include "automount.h"
#include "load-fragment.h"
#include "load-dropin.h"
#include "unit-name.h"
#include "dbus-automount.h"
#include "bus-errors.h"
#include "special.h"
#include "label.h"
#include "mkdir.h"
static const UnitActiveState state_translation_table[_AUTOMOUNT_STATE_MAX] = {
[AUTOMOUNT_DEAD] = UNIT_INACTIVE,
[AUTOMOUNT_WAITING] = UNIT_ACTIVE,
[AUTOMOUNT_RUNNING] = UNIT_ACTIVE,
[AUTOMOUNT_FAILED] = UNIT_FAILED
};
static int open_dev_autofs(Manager *m);
static void automount_init(Unit *u) {
Automount *a = AUTOMOUNT(u);
assert(u);
assert(u->load_state == UNIT_STUB);
a->pipe_watch.fd = a->pipe_fd = -1;
a->pipe_watch.type = WATCH_INVALID;
a->directory_mode = 0755;
UNIT(a)->ignore_on_isolate = true;
}
static void repeat_unmout(const char *path) {
assert(path);
for (;;) {
/* If there are multiple mounts on a mount point, this
* removes them all */
if (umount2(path, MNT_DETACH) >= 0)
continue;
if (errno != EINVAL)
log_error("Failed to unmount: %m");
break;
}
}
static void unmount_autofs(Automount *a) {
assert(a);
if (a->pipe_fd < 0)
return;
automount_send_ready(a, -EHOSTDOWN);
unit_unwatch_fd(UNIT(a), &a->pipe_watch);
close_nointr_nofail(a->pipe_fd);
a->pipe_fd = -1;
/* If we reload/reexecute things we keep the mount point
* around */
if (a->where &&
(UNIT(a)->manager->exit_code != MANAGER_RELOAD &&
UNIT(a)->manager->exit_code != MANAGER_REEXECUTE))
repeat_unmout(a->where);
}
static void automount_done(Unit *u) {
Automount *a = AUTOMOUNT(u);
assert(a);
unmount_autofs(a);
unit_ref_unset(&a->mount);
free(a->where);
a->where = NULL;
set_free(a->tokens);
a->tokens = NULL;
}
int automount_add_one_mount_link(Automount *a, Mount *m) {
int r;
assert(a);
assert(m);
if (UNIT(a)->load_state != UNIT_LOADED ||
UNIT(m)->load_state != UNIT_LOADED)
return 0;
if (!path_startswith(a->where, m->where))
return 0;
if (path_equal(a->where, m->where))
return 0;
if ((r = unit_add_two_dependencies(UNIT(a), UNIT_AFTER, UNIT_REQUIRES, UNIT(m), true)) < 0)
return r;
return 0;
}
static int automount_add_mount_links(Automount *a) {
Unit *other;
int r;
assert(a);
LIST_FOREACH(units_by_type, other, UNIT(a)->manager->units_by_type[UNIT_MOUNT])
if ((r = automount_add_one_mount_link(a, MOUNT(other))) < 0)
return r;
return 0;
}
static int automount_add_default_dependencies(Automount *a) {
int r;
assert(a);
if (UNIT(a)->manager->running_as == MANAGER_SYSTEM) {
if ((r = unit_add_dependency_by_name(UNIT(a), UNIT_BEFORE, SPECIAL_BASIC_TARGET, NULL, true)) < 0)
return r;
if ((r = unit_add_two_dependencies_by_name(UNIT(a), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_UMOUNT_TARGET, NULL, true)) < 0)
return r;
}
return 0;
}
static int automount_verify(Automount *a) {
bool b;
char *e;
assert(a);
if (UNIT(a)->load_state != UNIT_LOADED)
return 0;
if (path_equal(a->where, "/")) {
log_error("Cannot have an automount unit for the root directory. Refusing.");
return -EINVAL;
}
if (!(e = unit_name_from_path(a->where, ".automount")))
return -ENOMEM;
b = unit_has_name(UNIT(a), e);
free(e);
if (!b) {
log_error("%s's Where setting doesn't match unit name. Refusing.", UNIT(a)->id);
return -EINVAL;
}
return 0;
}
static int automount_load(Unit *u) {
int r;
Automount *a = AUTOMOUNT(u);
assert(u);
assert(u->load_state == UNIT_STUB);
/* Load a .automount file */
if ((r = unit_load_fragment_and_dropin_optional(u)) < 0)
return r;
if (u->load_state == UNIT_LOADED) {
Unit *x;
if (!a->where)
if (!(a->where = unit_name_to_path(u->id)))
return -ENOMEM;
path_kill_slashes(a->where);
if ((r = automount_add_mount_links(a)) < 0)
return r;
r = unit_load_related_unit(u, ".mount", &x);
if (r < 0)
return r;
unit_ref_set(&a->mount, x);
r = unit_add_two_dependencies(u, UNIT_BEFORE, UNIT_TRIGGERS, UNIT_DEREF(a->mount), true);
if (r < 0)
return r;
if (UNIT(a)->default_dependencies)
if ((r = automount_add_default_dependencies(a)) < 0)
return r;
}
return automount_verify(a);
}
static void automount_set_state(Automount *a, AutomountState state) {
AutomountState old_state;
assert(a);
old_state = a->state;
a->state = state;
if (state != AUTOMOUNT_WAITING &&
state != AUTOMOUNT_RUNNING)
unmount_autofs(a);
if (state != old_state)
log_debug("%s changed %s -> %s",
UNIT(a)->id,
automount_state_to_string(old_state),
automount_state_to_string(state));
unit_notify(UNIT(a), state_translation_table[old_state], state_translation_table[state], true);
}
static int automount_coldplug(Unit *u) {
Automount *a = AUTOMOUNT(u);
int r;
assert(a);
assert(a->state == AUTOMOUNT_DEAD);
if (a->deserialized_state != a->state) {
if ((r = open_dev_autofs(u->manager)) < 0)
return r;
if (a->deserialized_state == AUTOMOUNT_WAITING ||
a->deserialized_state == AUTOMOUNT_RUNNING) {
assert(a->pipe_fd >= 0);
if ((r = unit_watch_fd(UNIT(a), a->pipe_fd, EPOLLIN, &a->pipe_watch)) < 0)
return r;
}
automount_set_state(a, a->deserialized_state);
}
return 0;
}
static void automount_dump(Unit *u, FILE *f, const char *prefix) {
Automount *a = AUTOMOUNT(u);
assert(a);
fprintf(f,
"%sAutomount State: %s\n"
"%sResult: %s\n"
"%sWhere: %s\n"
"%sDirectoryMode: %04o\n",
prefix, automount_state_to_string(a->state),
prefix, automount_result_to_string(a->result),
prefix, a->where,
prefix, a->directory_mode);
}
static void automount_enter_dead(Automount *a, AutomountResult f) {
assert(a);
if (f != AUTOMOUNT_SUCCESS)
a->result = f;
automount_set_state(a, a->result != AUTOMOUNT_SUCCESS ? AUTOMOUNT_FAILED : AUTOMOUNT_DEAD);
}
static int open_dev_autofs(Manager *m) {
struct autofs_dev_ioctl param;
assert(m);
if (m->dev_autofs_fd >= 0)
return m->dev_autofs_fd;
label_fix("/dev/autofs", false);
if ((m->dev_autofs_fd = open("/dev/autofs", O_CLOEXEC|O_RDONLY)) < 0) {
log_error("Failed to open /dev/autofs: %s", strerror(errno));
return -errno;
}
init_autofs_dev_ioctl(&param);
if (ioctl(m->dev_autofs_fd, AUTOFS_DEV_IOCTL_VERSION, &param) < 0) {
close_nointr_nofail(m->dev_autofs_fd);
m->dev_autofs_fd = -1;
return -errno;
}
log_debug("Autofs kernel version %i.%i", param.ver_major, param.ver_minor);
return m->dev_autofs_fd;
}
static int open_ioctl_fd(int dev_autofs_fd, const char *where, dev_t devid) {
struct autofs_dev_ioctl *param;
size_t l;
int r;
assert(dev_autofs_fd >= 0);
assert(where);
l = sizeof(struct autofs_dev_ioctl) + strlen(where) + 1;
if (!(param = malloc(l)))
return -ENOMEM;
init_autofs_dev_ioctl(param);
param->size = l;
param->ioctlfd = -1;
param->openmount.devid = devid;
strcpy(param->path, where);
if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_OPENMOUNT, param) < 0) {
r = -errno;
goto finish;
}
if (param->ioctlfd < 0) {
r = -EIO;
goto finish;
}
fd_cloexec(param->ioctlfd, true);
r = param->ioctlfd;
finish:
free(param);
return r;
}
static int autofs_protocol(int dev_autofs_fd, int ioctl_fd) {
uint32_t major, minor;
struct autofs_dev_ioctl param;
assert(dev_autofs_fd >= 0);
assert(ioctl_fd >= 0);
init_autofs_dev_ioctl(&param);
param.ioctlfd = ioctl_fd;
if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_PROTOVER, &param) < 0)
return -errno;
major = param.protover.version;
init_autofs_dev_ioctl(&param);
param.ioctlfd = ioctl_fd;
if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_PROTOSUBVER, &param) < 0)
return -errno;
minor = param.protosubver.sub_version;
log_debug("Autofs protocol version %i.%i", major, minor);
return 0;
}
static int autofs_set_timeout(int dev_autofs_fd, int ioctl_fd, time_t sec) {
struct autofs_dev_ioctl param;
assert(dev_autofs_fd >= 0);
assert(ioctl_fd >= 0);
init_autofs_dev_ioctl(&param);
param.ioctlfd = ioctl_fd;
param.timeout.timeout = sec;
if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_TIMEOUT, &param) < 0)
return -errno;
return 0;
}
static int autofs_send_ready(int dev_autofs_fd, int ioctl_fd, uint32_t token, int status) {
struct autofs_dev_ioctl param;
assert(dev_autofs_fd >= 0);
assert(ioctl_fd >= 0);
init_autofs_dev_ioctl(&param);
param.ioctlfd = ioctl_fd;
if (status) {
param.fail.token = token;
param.fail.status = status;
} else
param.ready.token = token;
if (ioctl(dev_autofs_fd, status ? AUTOFS_DEV_IOCTL_FAIL : AUTOFS_DEV_IOCTL_READY, &param) < 0)
return -errno;
return 0;
}
int automount_send_ready(Automount *a, int status) {
int ioctl_fd, r;
unsigned token;
assert(a);
assert(status <= 0);
if (set_isempty(a->tokens))
return 0;
if ((ioctl_fd = open_ioctl_fd(UNIT(a)->manager->dev_autofs_fd, a->where, a->dev_id)) < 0) {
r = ioctl_fd;
goto fail;
}
if (status)
log_debug("Sending failure: %s", strerror(-status));
else
log_debug("Sending success.");
r = 0;
/* Autofs thankfully does not hand out 0 as a token */
while ((token = PTR_TO_UINT(set_steal_first(a->tokens)))) {
int k;
/* Autofs fun fact II:
*
* if you pass a positive status code here, the kernel will
* freeze! Yay! */
if ((k = autofs_send_ready(UNIT(a)->manager->dev_autofs_fd,
ioctl_fd,
token,
status)) < 0)
r = k;
}
fail:
if (ioctl_fd >= 0)
close_nointr_nofail(ioctl_fd);
return r;
}
static void automount_enter_waiting(Automount *a) {
int p[2] = { -1, -1 };
char name[32], options[128];
bool mounted = false;
int r, ioctl_fd = -1, dev_autofs_fd;
struct stat st;
assert(a);
assert(a->pipe_fd < 0);
assert(a->where);
if (a->tokens)
set_clear(a->tokens);
if ((dev_autofs_fd = open_dev_autofs(UNIT(a)->manager)) < 0) {
r = dev_autofs_fd;
goto fail;
}
/* We knowingly ignore the results of this call */
mkdir_p(a->where, 0555);
if (pipe2(p, O_NONBLOCK|O_CLOEXEC) < 0) {
r = -errno;
goto fail;
}
snprintf(options, sizeof(options), "fd=%i,pgrp=%u,minproto=5,maxproto=5,direct", p[1], (unsigned) getpgrp());
char_array_0(options);
snprintf(name, sizeof(name), "systemd-%u", (unsigned) getpid());
char_array_0(name);
if (mount(name, a->where, "autofs", 0, options) < 0) {
r = -errno;
goto fail;
}
mounted = true;
close_nointr_nofail(p[1]);
p[1] = -1;
if (stat(a->where, &st) < 0) {
r = -errno;
goto fail;
}
if ((ioctl_fd = open_ioctl_fd(dev_autofs_fd, a->where, st.st_dev)) < 0) {
r = ioctl_fd;
goto fail;
}
if ((r = autofs_protocol(dev_autofs_fd, ioctl_fd)) < 0)
goto fail;
if ((r = autofs_set_timeout(dev_autofs_fd, ioctl_fd, 300)) < 0)
goto fail;
/* Autofs fun fact:
*
* Unless we close the ioctl fd here, for some weird reason
* the direct mount will not receive events from the
* kernel. */
close_nointr_nofail(ioctl_fd);
ioctl_fd = -1;
if ((r = unit_watch_fd(UNIT(a), p[0], EPOLLIN, &a->pipe_watch)) < 0)
goto fail;
a->pipe_fd = p[0];
a->dev_id = st.st_dev;
automount_set_state(a, AUTOMOUNT_WAITING);
return;
fail:
assert_se(close_pipe(p) == 0);
if (ioctl_fd >= 0)
close_nointr_nofail(ioctl_fd);
if (mounted)
repeat_unmout(a->where);
log_error("Failed to initialize automounter: %s", strerror(-r));
automount_enter_dead(a, AUTOMOUNT_FAILURE_RESOURCES);
}
static void automount_enter_runnning(Automount *a) {
int r;
struct stat st;
DBusError error;
assert(a);
assert(UNIT_DEREF(a->mount));
dbus_error_init(&error);
/* We don't take mount requests anymore if we are supposed to
* shut down anyway */
if (unit_pending_inactive(UNIT(a))) {
log_debug("Suppressing automount request on %s since unit stop is scheduled.", UNIT(a)->id);
automount_send_ready(a, -EHOSTDOWN);
return;
}
mkdir_p(a->where, a->directory_mode);
/* Before we do anything, let's see if somebody is playing games with us? */
if (lstat(a->where, &st) < 0) {
log_warning("%s failed to stat automount point: %m", UNIT(a)->id);
goto fail;
}
if (!S_ISDIR(st.st_mode) || st.st_dev != a->dev_id)
log_info("%s's automount point already active?", UNIT(a)->id);
else if ((r = manager_add_job(UNIT(a)->manager, JOB_START, UNIT_DEREF(a->mount), JOB_REPLACE, true, &error, NULL)) < 0) {
log_warning("%s failed to queue mount startup job: %s", UNIT(a)->id, bus_error(&error, r));
goto fail;
}
automount_set_state(a, AUTOMOUNT_RUNNING);
return;
fail:
automount_enter_dead(a, AUTOMOUNT_FAILURE_RESOURCES);
dbus_error_free(&error);
}
static int automount_start(Unit *u) {
Automount *a = AUTOMOUNT(u);
assert(a);
assert(a->state == AUTOMOUNT_DEAD || a->state == AUTOMOUNT_FAILED);
if (path_is_mount_point(a->where, false)) {
log_error("Path %s is already a mount point, refusing start for %s", a->where, u->id);
return -EEXIST;
}
if (UNIT_DEREF(a->mount)->load_state != UNIT_LOADED)
return -ENOENT;
a->result = AUTOMOUNT_SUCCESS;
automount_enter_waiting(a);
return 0;
}
static int automount_stop(Unit *u) {
Automount *a = AUTOMOUNT(u);
assert(a);
assert(a->state == AUTOMOUNT_WAITING || a->state == AUTOMOUNT_RUNNING);
automount_enter_dead(a, AUTOMOUNT_SUCCESS);
return 0;
}
static int automount_serialize(Unit *u, FILE *f, FDSet *fds) {
Automount *a = AUTOMOUNT(u);
void *p;
Iterator i;
assert(a);
assert(f);
assert(fds);
unit_serialize_item(u, f, "state", automount_state_to_string(a->state));
unit_serialize_item(u, f, "result", automount_result_to_string(a->result));
unit_serialize_item_format(u, f, "dev-id", "%u", (unsigned) a->dev_id);
SET_FOREACH(p, a->tokens, i)
unit_serialize_item_format(u, f, "token", "%u", PTR_TO_UINT(p));
if (a->pipe_fd >= 0) {
int copy;
if ((copy = fdset_put_dup(fds, a->pipe_fd)) < 0)
return copy;
unit_serialize_item_format(u, f, "pipe-fd", "%i", copy);
}
return 0;
}
static int automount_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) {
Automount *a = AUTOMOUNT(u);
int r;
assert(a);
assert(fds);
if (streq(key, "state")) {
AutomountState state;
if ((state = automount_state_from_string(value)) < 0)
log_debug("Failed to parse state value %s", value);
else
a->deserialized_state = state;
} else if (streq(key, "result")) {
AutomountResult f;
f = automount_result_from_string(value);
if (f < 0)
log_debug("Failed to parse result value %s", value);
else if (f != AUTOMOUNT_SUCCESS)
a->result = f;
} else if (streq(key, "dev-id")) {
unsigned d;
if (safe_atou(value, &d) < 0)
log_debug("Failed to parse dev-id value %s", value);
else
a->dev_id = (unsigned) d;
} else if (streq(key, "token")) {
unsigned token;
if (safe_atou(value, &token) < 0)
log_debug("Failed to parse token value %s", value);
else {
if (!a->tokens)
if (!(a->tokens = set_new(trivial_hash_func, trivial_compare_func)))
return -ENOMEM;
if ((r = set_put(a->tokens, UINT_TO_PTR(token))) < 0)
return r;
}
} else if (streq(key, "pipe-fd")) {
int fd;
if (safe_atoi(value, &fd) < 0 || fd < 0 || !fdset_contains(fds, fd))
log_debug("Failed to parse pipe-fd value %s", value);
else {
if (a->pipe_fd >= 0)
close_nointr_nofail(a->pipe_fd);
a->pipe_fd = fdset_remove(fds, fd);
}
} else
log_debug("Unknown serialization key '%s'", key);
return 0;
}
static UnitActiveState automount_active_state(Unit *u) {
assert(u);
return state_translation_table[AUTOMOUNT(u)->state];
}
static const char *automount_sub_state_to_string(Unit *u) {
assert(u);
return automount_state_to_string(AUTOMOUNT(u)->state);
}
static bool automount_check_gc(Unit *u) {
Automount *a = AUTOMOUNT(u);
assert(a);
if (!UNIT_DEREF(a->mount))
return false;
return UNIT_VTABLE(UNIT_DEREF(a->mount))->check_gc(UNIT_DEREF(a->mount));
}
static void automount_fd_event(Unit *u, int fd, uint32_t events, Watch *w) {
Automount *a = AUTOMOUNT(u);
union autofs_v5_packet_union packet;
ssize_t l;
int r;
assert(a);
assert(fd == a->pipe_fd);
if (events != EPOLLIN) {
log_error("Got invalid poll event on pipe.");
goto fail;
}
if ((l = loop_read(a->pipe_fd, &packet, sizeof(packet), true)) != sizeof(packet)) {
log_error("Invalid read from pipe: %s", l < 0 ? strerror(-l) : "short read");
goto fail;
}
switch (packet.hdr.type) {
case autofs_ptype_missing_direct:
if (packet.v5_packet.pid > 0) {
char *p = NULL;
get_process_comm(packet.v5_packet.pid, &p);
log_debug("Got direct mount request for %s, triggered by %lu (%s)", packet.v5_packet.name, (unsigned long) packet.v5_packet.pid, strna(p));
free(p);
} else
log_debug("Got direct mount request for %s", packet.v5_packet.name);
if (!a->tokens)
if (!(a->tokens = set_new(trivial_hash_func, trivial_compare_func))) {
log_error("Failed to allocate token set.");
goto fail;
}
if ((r = set_put(a->tokens, UINT_TO_PTR(packet.v5_packet.wait_queue_token))) < 0) {
log_error("Failed to remember token: %s", strerror(-r));
goto fail;
}
automount_enter_runnning(a);
break;
default:
log_error("Received unknown automount request %i", packet.hdr.type);
break;
}
return;
fail:
automount_enter_dead(a, AUTOMOUNT_FAILURE_RESOURCES);
}
static void automount_shutdown(Manager *m) {
assert(m);
if (m->dev_autofs_fd >= 0)
close_nointr_nofail(m->dev_autofs_fd);
}
static void automount_reset_failed(Unit *u) {
Automount *a = AUTOMOUNT(u);
assert(a);
if (a->state == AUTOMOUNT_FAILED)
automount_set_state(a, AUTOMOUNT_DEAD);
a->result = AUTOMOUNT_SUCCESS;
}
static const char* const automount_state_table[_AUTOMOUNT_STATE_MAX] = {
[AUTOMOUNT_DEAD] = "dead",
[AUTOMOUNT_WAITING] = "waiting",
[AUTOMOUNT_RUNNING] = "running",
[AUTOMOUNT_FAILED] = "failed"
};
DEFINE_STRING_TABLE_LOOKUP(automount_state, AutomountState);
static const char* const automount_result_table[_AUTOMOUNT_RESULT_MAX] = {
[AUTOMOUNT_SUCCESS] = "success",
[AUTOMOUNT_FAILURE_RESOURCES] = "resources"
};
DEFINE_STRING_TABLE_LOOKUP(automount_result, AutomountResult);
const UnitVTable automount_vtable = {
.suffix = ".automount",
.object_size = sizeof(Automount),
.sections =
"Unit\0"
"Automount\0"
"Install\0",
.no_alias = true,
.no_instances = true,
.init = automount_init,
.load = automount_load,
.done = automount_done,
.coldplug = automount_coldplug,
.dump = automount_dump,
.start = automount_start,
.stop = automount_stop,
.serialize = automount_serialize,
.deserialize_item = automount_deserialize_item,
.active_state = automount_active_state,
.sub_state_to_string = automount_sub_state_to_string,
.check_gc = automount_check_gc,
.fd_event = automount_fd_event,
.reset_failed = automount_reset_failed,
.bus_interface = "org.freedesktop.systemd1.Automount",
.bus_message_handler = bus_automount_message_handler,
.bus_invalidating_properties = bus_automount_invalidating_properties,
.shutdown = automount_shutdown
};
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