/*** 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 = MANAGER_IS_USER(u->manager) ? "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 (dev && 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_debug(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.", }, }, };