diff options
Diffstat (limited to 'src/libcore/device.c')
| -rw-r--r-- | src/libcore/device.c | 878 |
1 files changed, 878 insertions, 0 deletions
diff --git a/src/libcore/device.c b/src/libcore/device.c new file mode 100644 index 0000000000..d201dc5e4b --- /dev/null +++ b/src/libcore/device.c @@ -0,0 +1,878 @@ +/*** + 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 <sys/epoll.h> + +#include "libudev.h" + +#include "alloc-util.h" +#include "dbus-device.h" +#include "device.h" +#include "log.h" +#include "parse-util.h" +#include "path-util.h" +#include "stat-util.h" +#include "string-util.h" +#include "swap.h" +#include "udev-util.h" +#include "unit-name.h" +#include "unit.h" + +static const UnitActiveState state_translation_table[_DEVICE_STATE_MAX] = { + [DEVICE_DEAD] = UNIT_INACTIVE, + [DEVICE_TENTATIVE] = UNIT_ACTIVATING, + [DEVICE_PLUGGED] = UNIT_ACTIVE, +}; + +static int device_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata); + +static void device_unset_sysfs(Device *d) { + Hashmap *devices; + Device *first; + + assert(d); + + if (!d->sysfs) + return; + + /* Remove this unit from the chain of devices which share the + * same sysfs path. */ + devices = UNIT(d)->manager->devices_by_sysfs; + first = hashmap_get(devices, d->sysfs); + LIST_REMOVE(same_sysfs, first, d); + + if (first) + hashmap_remove_and_replace(devices, d->sysfs, first->sysfs, first); + else + hashmap_remove(devices, d->sysfs); + + d->sysfs = mfree(d->sysfs); +} + +static int device_set_sysfs(Device *d, const char *sysfs) { + Device *first; + char *copy; + int r; + + assert(d); + + if (streq_ptr(d->sysfs, sysfs)) + return 0; + + r = hashmap_ensure_allocated(&UNIT(d)->manager->devices_by_sysfs, &string_hash_ops); + if (r < 0) + return r; + + copy = strdup(sysfs); + if (!copy) + return -ENOMEM; + + device_unset_sysfs(d); + + first = hashmap_get(UNIT(d)->manager->devices_by_sysfs, sysfs); + LIST_PREPEND(same_sysfs, first, d); + + r = hashmap_replace(UNIT(d)->manager->devices_by_sysfs, copy, first); + if (r < 0) { + LIST_REMOVE(same_sysfs, first, d); + free(copy); + return r; + } + + d->sysfs = copy; + + return 0; +} + +static void device_init(Unit *u) { + Device *d = DEVICE(u); + + assert(d); + assert(UNIT(d)->load_state == UNIT_STUB); + + /* In contrast to all other unit types we timeout jobs waiting + * for devices by default. This is because they otherwise wait + * indefinitely for plugged in devices, something which cannot + * happen for the other units since their operations time out + * anyway. */ + u->job_timeout = u->manager->default_timeout_start_usec; + + u->ignore_on_isolate = true; +} + +static void device_done(Unit *u) { + Device *d = DEVICE(u); + + assert(d); + + device_unset_sysfs(d); +} + +static void device_set_state(Device *d, DeviceState state) { + DeviceState old_state; + assert(d); + + old_state = d->state; + d->state = state; + + if (state != old_state) + log_unit_debug(UNIT(d), "Changed %s -> %s", device_state_to_string(old_state), device_state_to_string(state)); + + unit_notify(UNIT(d), state_translation_table[old_state], state_translation_table[state], true); +} + +static int device_coldplug(Unit *u) { + Device *d = DEVICE(u); + + assert(d); + assert(d->state == DEVICE_DEAD); + + if (d->found & DEVICE_FOUND_UDEV) + /* If udev says the device is around, it's around */ + device_set_state(d, DEVICE_PLUGGED); + else if (d->found != DEVICE_NOT_FOUND && d->deserialized_state != DEVICE_PLUGGED) + /* If a device is found in /proc/self/mountinfo or + * /proc/swaps, and was not yet announced via udev, + * it's "tentatively" around. */ + device_set_state(d, DEVICE_TENTATIVE); + + return 0; +} + +static int device_serialize(Unit *u, FILE *f, FDSet *fds) { + Device *d = DEVICE(u); + + assert(u); + assert(f); + assert(fds); + + unit_serialize_item(u, f, "state", device_state_to_string(d->state)); + + return 0; +} + +static int device_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) { + Device *d = DEVICE(u); + + assert(u); + assert(key); + assert(value); + assert(fds); + + if (streq(key, "state")) { + DeviceState state; + + state = device_state_from_string(value); + if (state < 0) + log_unit_debug(u, "Failed to parse state value: %s", value); + else + d->deserialized_state = state; + } else + log_unit_debug(u, "Unknown serialization key: %s", key); + + return 0; +} + +static void device_dump(Unit *u, FILE *f, const char *prefix) { + Device *d = DEVICE(u); + + assert(d); + + fprintf(f, + "%sDevice State: %s\n" + "%sSysfs Path: %s\n", + prefix, device_state_to_string(d->state), + prefix, strna(d->sysfs)); +} + +_pure_ static UnitActiveState device_active_state(Unit *u) { + assert(u); + + return state_translation_table[DEVICE(u)->state]; +} + +_pure_ static const char *device_sub_state_to_string(Unit *u) { + assert(u); + + return device_state_to_string(DEVICE(u)->state); +} + +static int device_update_description(Unit *u, struct udev_device *dev, const char *path) { + const char *model; + int r; + + assert(u); + assert(dev); + assert(path); + + model = udev_device_get_property_value(dev, "ID_MODEL_FROM_DATABASE"); + if (!model) + model = udev_device_get_property_value(dev, "ID_MODEL"); + + if (model) { + const char *label; + + /* Try to concatenate the device model string with a label, if there is one */ + label = udev_device_get_property_value(dev, "ID_FS_LABEL"); + if (!label) + label = udev_device_get_property_value(dev, "ID_PART_ENTRY_NAME"); + if (!label) + label = udev_device_get_property_value(dev, "ID_PART_ENTRY_NUMBER"); + + if (label) { + _cleanup_free_ char *j; + + j = strjoin(model, " ", label, NULL); + if (j) + r = unit_set_description(u, j); + else + r = -ENOMEM; + } else + r = unit_set_description(u, model); + } else + r = unit_set_description(u, path); + + if (r < 0) + log_unit_error_errno(u, r, "Failed to set device description: %m"); + + return r; +} + +static int device_add_udev_wants(Unit *u, struct udev_device *dev) { + const char *wants; + const char *word, *state; + size_t l; + int r; + const char *property; + + assert(u); + assert(dev); + + property = u->manager->running_as == MANAGER_USER ? "SYSTEMD_USER_WANTS" : "SYSTEMD_WANTS"; + wants = udev_device_get_property_value(dev, property); + if (!wants) + return 0; + + FOREACH_WORD_QUOTED(word, l, wants, state) { + _cleanup_free_ char *n = NULL; + char e[l+1]; + + memcpy(e, word, l); + e[l] = 0; + + r = unit_name_mangle(e, UNIT_NAME_NOGLOB, &n); + if (r < 0) + return log_unit_error_errno(u, r, "Failed to mangle unit name: %m"); + + r = unit_add_dependency_by_name(u, UNIT_WANTS, n, NULL, true); + if (r < 0) + return log_unit_error_errno(u, r, "Failed to add wants dependency: %m"); + } + if (!isempty(state)) + log_unit_warning(u, "Property %s on %s has trailing garbage, ignoring.", property, strna(udev_device_get_syspath(dev))); + + return 0; +} + +static int device_setup_unit(Manager *m, struct udev_device *dev, const char *path, bool main) { + _cleanup_free_ char *e = NULL; + const char *sysfs = NULL; + Unit *u = NULL; + bool delete; + int r; + + assert(m); + assert(path); + + if (dev) { + sysfs = udev_device_get_syspath(dev); + if (!sysfs) + return 0; + } + + r = unit_name_from_path(path, ".device", &e); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name from device path: %m"); + + u = manager_get_unit(m, e); + + /* The device unit can still be present even if the device was + * unplugged: a mount unit can reference it hence preventing + * the GC to have garbaged it. That's desired since the device + * unit may have a dependency on the mount unit which was + * added during the loading of the later. */ + if (u && DEVICE(u)->state == DEVICE_PLUGGED) { + /* This unit is in plugged state: we're sure it's + * attached to a device. */ + if (!path_equal(DEVICE(u)->sysfs, sysfs)) { + log_unit_error(u, "Dev %s appeared twice with different sysfs paths %s and %s", + e, DEVICE(u)->sysfs, sysfs); + return -EEXIST; + } + } + + if (!u) { + delete = true; + + u = unit_new(m, sizeof(Device)); + if (!u) + return log_oom(); + + r = unit_add_name(u, e); + if (r < 0) + goto fail; + + unit_add_to_load_queue(u); + } else + delete = false; + + /* If this was created via some dependency and has not + * actually been seen yet ->sysfs will not be + * initialized. Hence initialize it if necessary. */ + if (sysfs) { + r = device_set_sysfs(DEVICE(u), sysfs); + if (r < 0) + goto fail; + + (void) device_update_description(u, dev, path); + + /* The additional systemd udev properties we only interpret + * for the main object */ + if (main) + (void) device_add_udev_wants(u, dev); + } + + + /* Note that this won't dispatch the load queue, the caller + * has to do that if needed and appropriate */ + + unit_add_to_dbus_queue(u); + return 0; + +fail: + log_unit_warning_errno(u, r, "Failed to set up device unit: %m"); + + if (delete) + unit_free(u); + + return r; +} + +static int device_process_new(Manager *m, struct udev_device *dev) { + const char *sysfs, *dn, *alias; + struct udev_list_entry *item = NULL, *first = NULL; + int r; + + assert(m); + + sysfs = udev_device_get_syspath(dev); + if (!sysfs) + return 0; + + /* Add the main unit named after the sysfs path */ + r = device_setup_unit(m, dev, sysfs, true); + if (r < 0) + return r; + + /* Add an additional unit for the device node */ + dn = udev_device_get_devnode(dev); + if (dn) + (void) device_setup_unit(m, dev, dn, false); + + /* Add additional units for all symlinks */ + first = udev_device_get_devlinks_list_entry(dev); + udev_list_entry_foreach(item, first) { + const char *p; + struct stat st; + + /* Don't bother with the /dev/block links */ + p = udev_list_entry_get_name(item); + + if (path_startswith(p, "/dev/block/") || + path_startswith(p, "/dev/char/")) + continue; + + /* Verify that the symlink in the FS actually belongs + * to this device. This is useful to deal with + * conflicting devices, e.g. when two disks want the + * same /dev/disk/by-label/xxx link because they have + * the same label. We want to make sure that the same + * device that won the symlink wins in systemd, so we + * check the device node major/minor */ + if (stat(p, &st) >= 0) + if ((!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode)) || + st.st_rdev != udev_device_get_devnum(dev)) + continue; + + (void) device_setup_unit(m, dev, p, false); + } + + /* Add additional units for all explicitly configured + * aliases */ + alias = udev_device_get_property_value(dev, "SYSTEMD_ALIAS"); + if (alias) { + const char *word, *state; + size_t l; + + FOREACH_WORD_QUOTED(word, l, alias, state) { + char e[l+1]; + + memcpy(e, word, l); + e[l] = 0; + + if (path_is_absolute(e)) + (void) device_setup_unit(m, dev, e, false); + else + log_warning("SYSTEMD_ALIAS for %s is not an absolute path, ignoring: %s", sysfs, e); + } + if (!isempty(state)) + log_warning("SYSTEMD_ALIAS for %s has trailing garbage, ignoring.", sysfs); + } + + return 0; +} + +static void device_update_found_one(Device *d, bool add, DeviceFound found, bool now) { + DeviceFound n, previous; + + assert(d); + + n = add ? (d->found | found) : (d->found & ~found); + if (n == d->found) + return; + + previous = d->found; + d->found = n; + + if (!now) + return; + + if (d->found & DEVICE_FOUND_UDEV) + /* When the device is known to udev we consider it + * plugged. */ + device_set_state(d, DEVICE_PLUGGED); + else if (d->found != DEVICE_NOT_FOUND && (previous & DEVICE_FOUND_UDEV) == 0) + /* If the device has not been seen by udev yet, but is + * now referenced by the kernel, then we assume the + * kernel knows it now, and udev might soon too. */ + device_set_state(d, DEVICE_TENTATIVE); + else + /* If nobody sees the device, or if the device was + * previously seen by udev and now is only referenced + * from the kernel, then we consider the device is + * gone, the kernel just hasn't noticed it yet. */ + device_set_state(d, DEVICE_DEAD); +} + +static int device_update_found_by_sysfs(Manager *m, const char *sysfs, bool add, DeviceFound found, bool now) { + Device *d, *l; + + assert(m); + assert(sysfs); + + if (found == DEVICE_NOT_FOUND) + return 0; + + l = hashmap_get(m->devices_by_sysfs, sysfs); + LIST_FOREACH(same_sysfs, d, l) + device_update_found_one(d, add, found, now); + + return 0; +} + +static int device_update_found_by_name(Manager *m, const char *path, bool add, DeviceFound found, bool now) { + _cleanup_free_ char *e = NULL; + Unit *u; + int r; + + assert(m); + assert(path); + + if (found == DEVICE_NOT_FOUND) + return 0; + + r = unit_name_from_path(path, ".device", &e); + if (r < 0) + return log_error_errno(r, "Failed to generate unit name from device path: %m"); + + u = manager_get_unit(m, e); + if (!u) + return 0; + + device_update_found_one(DEVICE(u), add, found, now); + return 0; +} + +static bool device_is_ready(struct udev_device *dev) { + const char *ready; + + assert(dev); + + ready = udev_device_get_property_value(dev, "SYSTEMD_READY"); + if (!ready) + return true; + + return parse_boolean(ready) != 0; +} + +static Unit *device_following(Unit *u) { + Device *d = DEVICE(u); + Device *other, *first = NULL; + + assert(d); + + if (startswith(u->id, "sys-")) + return NULL; + + /* Make everybody follow the unit that's named after the sysfs path */ + for (other = d->same_sysfs_next; other; other = other->same_sysfs_next) + if (startswith(UNIT(other)->id, "sys-")) + return UNIT(other); + + for (other = d->same_sysfs_prev; other; other = other->same_sysfs_prev) { + if (startswith(UNIT(other)->id, "sys-")) + return UNIT(other); + + first = other; + } + + return UNIT(first); +} + +static int device_following_set(Unit *u, Set **_set) { + Device *d = DEVICE(u), *other; + Set *set; + int r; + + assert(d); + assert(_set); + + if (LIST_JUST_US(same_sysfs, d)) { + *_set = NULL; + return 0; + } + + set = set_new(NULL); + if (!set) + return -ENOMEM; + + LIST_FOREACH_AFTER(same_sysfs, other, d) { + r = set_put(set, other); + if (r < 0) + goto fail; + } + + LIST_FOREACH_BEFORE(same_sysfs, other, d) { + r = set_put(set, other); + if (r < 0) + goto fail; + } + + *_set = set; + return 1; + +fail: + set_free(set); + return r; +} + +static void device_shutdown(Manager *m) { + assert(m); + + m->udev_event_source = sd_event_source_unref(m->udev_event_source); + + if (m->udev_monitor) { + udev_monitor_unref(m->udev_monitor); + m->udev_monitor = NULL; + } + + m->devices_by_sysfs = hashmap_free(m->devices_by_sysfs); +} + +static void device_enumerate(Manager *m) { + _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL; + struct udev_list_entry *item = NULL, *first = NULL; + int r; + + assert(m); + + if (!m->udev_monitor) { + m->udev_monitor = udev_monitor_new_from_netlink(m->udev, "udev"); + if (!m->udev_monitor) { + log_oom(); + goto fail; + } + + /* This will fail if we are unprivileged, but that + * should not matter much, as user instances won't run + * during boot. */ + (void) udev_monitor_set_receive_buffer_size(m->udev_monitor, 128*1024*1024); + + r = udev_monitor_filter_add_match_tag(m->udev_monitor, "systemd"); + if (r < 0) { + log_error_errno(r, "Failed to add udev tag match: %m"); + goto fail; + } + + r = udev_monitor_enable_receiving(m->udev_monitor); + if (r < 0) { + log_error_errno(r, "Failed to enable udev event reception: %m"); + goto fail; + } + + r = sd_event_add_io(m->event, &m->udev_event_source, udev_monitor_get_fd(m->udev_monitor), EPOLLIN, device_dispatch_io, m); + if (r < 0) { + log_error_errno(r, "Failed to watch udev file descriptor: %m"); + goto fail; + } + + (void) sd_event_source_set_description(m->udev_event_source, "device"); + } + + e = udev_enumerate_new(m->udev); + if (!e) { + log_oom(); + goto fail; + } + + r = udev_enumerate_add_match_tag(e, "systemd"); + if (r < 0) { + log_error_errno(r, "Failed to create udev tag enumeration: %m"); + goto fail; + } + + r = udev_enumerate_add_match_is_initialized(e); + if (r < 0) { + log_error_errno(r, "Failed to install initialization match into enumeration: %m"); + goto fail; + } + + r = udev_enumerate_scan_devices(e); + if (r < 0) { + log_error_errno(r, "Failed to enumerate devices: %m"); + goto fail; + } + + first = udev_enumerate_get_list_entry(e); + udev_list_entry_foreach(item, first) { + _cleanup_udev_device_unref_ struct udev_device *dev = NULL; + const char *sysfs; + + sysfs = udev_list_entry_get_name(item); + + dev = udev_device_new_from_syspath(m->udev, sysfs); + if (!dev) { + log_oom(); + continue; + } + + if (!device_is_ready(dev)) + continue; + + (void) device_process_new(m, dev); + + device_update_found_by_sysfs(m, sysfs, true, DEVICE_FOUND_UDEV, false); + } + + return; + +fail: + device_shutdown(m); +} + +static int device_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) { + _cleanup_udev_device_unref_ struct udev_device *dev = NULL; + Manager *m = userdata; + const char *action, *sysfs; + int r; + + assert(m); + + if (revents != EPOLLIN) { + static RATELIMIT_DEFINE(limit, 10*USEC_PER_SEC, 5); + + if (!ratelimit_test(&limit)) + log_error_errno(errno, "Failed to get udev event: %m"); + if (!(revents & EPOLLIN)) + return 0; + } + + /* + * libudev might filter-out devices which pass the bloom + * filter, so getting NULL here is not necessarily an error. + */ + dev = udev_monitor_receive_device(m->udev_monitor); + if (!dev) + return 0; + + sysfs = udev_device_get_syspath(dev); + if (!sysfs) { + log_error("Failed to get udev sys path."); + return 0; + } + + action = udev_device_get_action(dev); + if (!action) { + log_error("Failed to get udev action string."); + return 0; + } + + if (streq(action, "remove")) { + r = swap_process_device_remove(m, dev); + if (r < 0) + log_error_errno(r, "Failed to process swap device remove event: %m"); + + /* If we get notified that a device was removed by + * udev, then it's completely gone, hence unset all + * found bits */ + device_update_found_by_sysfs(m, sysfs, false, DEVICE_FOUND_UDEV|DEVICE_FOUND_MOUNT|DEVICE_FOUND_SWAP, true); + + } else if (device_is_ready(dev)) { + + (void) device_process_new(m, dev); + + r = swap_process_device_new(m, dev); + if (r < 0) + log_error_errno(r, "Failed to process swap device new event: %m"); + + manager_dispatch_load_queue(m); + + /* The device is found now, set the udev found bit */ + device_update_found_by_sysfs(m, sysfs, true, DEVICE_FOUND_UDEV, true); + + } else { + /* The device is nominally around, but not ready for + * us. Hence unset the udev bit, but leave the rest + * around. */ + + device_update_found_by_sysfs(m, sysfs, false, DEVICE_FOUND_UDEV, true); + } + + return 0; +} + +static bool device_supported(void) { + static int read_only = -1; + + /* If /sys is read-only we don't support device units, and any + * attempts to start one should fail immediately. */ + + if (read_only < 0) + read_only = path_is_read_only_fs("/sys"); + + return read_only <= 0; +} + +int device_found_node(Manager *m, const char *node, bool add, DeviceFound found, bool now) { + _cleanup_udev_device_unref_ struct udev_device *dev = NULL; + struct stat st; + + assert(m); + assert(node); + + if (!device_supported()) + return 0; + + /* This is called whenever we find a device referenced in + * /proc/swaps or /proc/self/mounts. Such a device might be + * mounted/enabled at a time where udev has not finished + * probing it yet, and we thus haven't learned about it + * yet. In this case we will set the device unit to + * "tentative" state. */ + + if (add) { + if (!path_startswith(node, "/dev")) + return 0; + + /* We make an extra check here, if the device node + * actually exists. If it's missing, then this is an + * indication that device was unplugged but is still + * referenced in /proc/swaps or + * /proc/self/mountinfo. Note that this check doesn't + * really cover all cases where a device might be gone + * away, since drives that can have a medium inserted + * will still have a device node even when the medium + * is not there... */ + + if (stat(node, &st) >= 0) { + if (!S_ISBLK(st.st_mode) && !S_ISCHR(st.st_mode)) + return 0; + + dev = udev_device_new_from_devnum(m->udev, S_ISBLK(st.st_mode) ? 'b' : 'c', st.st_rdev); + if (!dev && errno != ENOENT) + return log_error_errno(errno, "Failed to get udev device from devnum %u:%u: %m", major(st.st_rdev), minor(st.st_rdev)); + + } else if (errno != ENOENT) + return log_error_errno(errno, "Failed to stat device node file %s: %m", node); + + /* If the device is known in the kernel and newly + * appeared, then we'll create a device unit for it, + * under the name referenced in /proc/swaps or + * /proc/self/mountinfo. */ + + (void) device_setup_unit(m, dev, node, false); + } + + /* Update the device unit's state, should it exist */ + return device_update_found_by_name(m, node, add, found, now); +} + +const UnitVTable device_vtable = { + .object_size = sizeof(Device), + .sections = + "Unit\0" + "Device\0" + "Install\0", + + .no_instances = true, + + .init = device_init, + .done = device_done, + .load = unit_load_fragment_and_dropin_optional, + + .coldplug = device_coldplug, + + .serialize = device_serialize, + .deserialize_item = device_deserialize_item, + + .dump = device_dump, + + .active_state = device_active_state, + .sub_state_to_string = device_sub_state_to_string, + + .bus_vtable = bus_device_vtable, + + .following = device_following, + .following_set = device_following_set, + + .enumerate = device_enumerate, + .shutdown = device_shutdown, + .supported = device_supported, + + .status_message_formats = { + .starting_stopping = { + [0] = "Expecting device %s...", + }, + .finished_start_job = { + [JOB_DONE] = "Found device %s.", + [JOB_TIMEOUT] = "Timed out waiting for device %s.", + }, + }, +}; |