diff options
Diffstat (limited to 'src/automount.c')
| -rw-r--r-- | src/automount.c | 784 |
1 files changed, 784 insertions, 0 deletions
diff --git a/src/automount.c b/src/automount.c new file mode 100644 index 0000000000..465354f555 --- /dev/null +++ b/src/automount.c @@ -0,0 +1,784 @@ +/*-*- Mode: C; c-basic-offset: 8 -*-*/ + +/*** + 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 General Public License as published by + the Free Software Foundation; either version 2 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 + General Public License for more details. + + You should have received a copy of the GNU 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" + +static const UnitActiveState state_translation_table[_AUTOMOUNT_STATE_MAX] = { + [AUTOMOUNT_DEAD] = UNIT_INACTIVE, + [AUTOMOUNT_WAITING] = UNIT_ACTIVE, + [AUTOMOUNT_RUNNING] = UNIT_ACTIVE, + [AUTOMOUNT_MAINTAINANCE] = UNIT_INACTIVE, +}; + +static int open_dev_autofs(Manager *m); + +static void automount_init(Unit *u) { + Automount *a = AUTOMOUNT(u); + + assert(u); + assert(u->meta.load_state == UNIT_STUB); + + a->pipe_watch.fd = a->pipe_fd = -1; + a->pipe_watch.type = WATCH_INVALID; +} + +static void repeat_unmout(const char *path) { + assert(path); + + for (;;) { + + 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)->meta.manager->exit_code != MANAGER_RELOAD && + UNIT(a)->meta.manager->exit_code != MANAGER_REEXECUTE)) + repeat_unmout(a->where); +} + +static void automount_done(Unit *u) { + Automount *a = AUTOMOUNT(u); + + assert(a); + + unmount_autofs(a); + a->mount = NULL; + + 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 (a->meta.load_state != UNIT_LOADED || + m->meta.load_state != UNIT_LOADED) + return 0; + + if (!path_startswith(a->where, m->where)) + return 0; + + if ((r = unit_add_dependency(UNIT(m), UNIT_BEFORE, UNIT(a), true)) < 0) + return r; + + if ((r = unit_add_dependency(UNIT(a), UNIT_REQUIRES, UNIT(m), true)) < 0) + return r; + + return 0; +} + +static int automount_add_mount_links(Automount *a) { + Meta *other; + int r; + + assert(a); + + LIST_FOREACH(units_per_type, other, a->meta.manager->units_per_type[UNIT_MOUNT]) + if ((r = automount_add_one_mount_link(a, (Mount*) other)) < 0) + return r; + + return 0; +} + +static int automount_verify(Automount *a) { + bool b; + char *e; + assert(a); + + if (UNIT(a)->meta.load_state != UNIT_LOADED) + return 0; + + 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)->meta.id); + return -EINVAL; + } + + return 0; +} + +static int automount_load(Unit *u) { + int r; + Automount *a = AUTOMOUNT(u); + + assert(u); + assert(u->meta.load_state == UNIT_STUB); + + /* Load a .automount file */ + if ((r = unit_load_fragment_and_dropin_optional(u)) < 0) + return r; + + if (u->meta.load_state == UNIT_LOADED) { + + if (!a->where) + if (!(a->where = unit_name_to_path(u->meta.id))) + return -ENOMEM; + + path_kill_slashes(a->where); + + if ((r = automount_add_mount_links(a)) < 0) + return r; + + if ((r = unit_load_related_unit(u, ".mount", (Unit**) &a->mount)) < 0) + return r; + + if ((r = unit_add_dependency(u, UNIT_BEFORE, UNIT(a->mount), true)) < 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)->meta.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]); +} + +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->meta.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" + "%sWhere: %s\n", + prefix, automount_state_to_string(a->state), + prefix, a->where); +} + +static void automount_enter_dead(Automount *a, bool success) { + assert(a); + + if (!success) + a->failure = true; + + automount_set_state(a, a->failure ? AUTOMOUNT_MAINTAINANCE : 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; + + 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(¶m); + if (ioctl(m->dev_autofs_fd, AUTOFS_DEV_IOCTL_VERSION, ¶m) < 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(¶m); + param.ioctlfd = ioctl_fd; + + if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_PROTOVER, ¶m) < 0) + return -errno; + + major = param.protover.version; + + init_autofs_dev_ioctl(¶m); + param.ioctlfd = ioctl_fd; + + if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_PROTOSUBVER, ¶m) < 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(¶m); + param.ioctlfd = ioctl_fd; + param.timeout.timeout = sec; + + if (ioctl(dev_autofs_fd, AUTOFS_DEV_IOCTL_TIMEOUT, ¶m) < 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(¶m); + 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, ¶m) < 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)->meta.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."); + + /* 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)->meta.manager->dev_autofs_fd, + ioctl_fd, + token, + status)) < 0) + r = k; + } + + r = 0; + +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)->meta.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, false); +} + +static void automount_enter_runnning(Automount *a) { + int r; + struct stat st; + + assert(a); + assert(a->mount); + + /* Before we do anything, let's see if somebody is playing games with us? */ + + if (stat(a->where, &st) < 0) { + log_warning("%s failed stat automount point: %m", a->meta.id); + goto fail; + } + + if (!S_ISDIR(st.st_mode) || st.st_dev != a->dev_id) + log_info("%s's automount point already active?", a->meta.id); + else if ((r = manager_add_job(UNIT(a)->meta.manager, JOB_START, UNIT(a->mount), JOB_REPLACE, true, NULL)) < 0) { + log_warning("%s failed to queue mount startup job: %s", a->meta.id, strerror(-r)); + goto fail; + } + + automount_set_state(a, AUTOMOUNT_RUNNING); + return; + +fail: + automount_enter_dead(a, false); +} + +static int automount_start(Unit *u) { + Automount *a = AUTOMOUNT(u); + + assert(a); + + if (path_is_mount_point(a->where)) { + log_error("Path %s is already a mount point, refusing start for %s", a->where, u->meta.id); + return -EEXIST; + } + + assert(a->state == AUTOMOUNT_DEAD || a->state == AUTOMOUNT_MAINTAINANCE); + + a->failure = false; + 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, true); + 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, "failure", yes_no(a->failure)); + 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, "failure")) { + int b; + + if ((b = parse_boolean(value)) < 0) + log_debug("Failed to parse failure value %s", value); + else + a->failure = b || a->failure; + } 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); + + return UNIT_VTABLE(UNIT(a->mount))->check_gc(UNIT(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))) != 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: + 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, false); +} + +static void automount_shutdown(Manager *m) { + assert(m); + + if (m->dev_autofs_fd >= 0) + close_nointr_nofail(m->dev_autofs_fd); +} + +static const char* const automount_state_table[_AUTOMOUNT_STATE_MAX] = { + [AUTOMOUNT_DEAD] = "dead", + [AUTOMOUNT_WAITING] = "waiting", + [AUTOMOUNT_RUNNING] = "running", + [AUTOMOUNT_MAINTAINANCE] = "maintainance" +}; + +DEFINE_STRING_TABLE_LOOKUP(automount_state, AutomountState); + +const UnitVTable automount_vtable = { + .suffix = ".automount", + + .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, + + .bus_message_handler = bus_automount_message_handler, + + .shutdown = automount_shutdown +}; |