/* SPDX-License-Identifier: LGPL-2.1+ */ /*** Copyright 2010 Lennart Poettering ***/ #include #include #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_update_found_one(Device *d, DeviceFound found, DeviceFound mask); 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) { _cleanup_free_ char *copy = NULL; Device *first; int r; assert(d); if (streq_ptr(d->sysfs, sysfs)) return 0; r = hashmap_ensure_allocated(&UNIT(d)->manager->devices_by_sysfs, &path_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); return r; } d->sysfs = TAKE_PTR(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_running_timeout = u->manager->default_timeout_start_usec; u->ignore_on_isolate = true; d->deserialized_state = _DEVICE_STATE_INVALID; } 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 == DEVICE_DEAD) device_unset_sysfs(d); 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], 0); } static int device_coldplug(Unit *u) { Device *d = DEVICE(u); assert(d); assert(d->state == DEVICE_DEAD); /* First, let's put the deserialized state and found mask into effect, if we have it. */ if (d->deserialized_state < 0 || (d->deserialized_state == d->state && d->deserialized_found == d->found)) return 0; d->found = d->deserialized_found; device_set_state(d, d->deserialized_state); return 0; } static void device_catchup(Unit *u) { Device *d = DEVICE(u); assert(d); /* Second, let's update the state with the enumerated state if it's different */ if (d->enumerated_found == d->found) return; device_update_found_one(d, d->enumerated_found, DEVICE_FOUND_MASK); } static const struct { DeviceFound flag; const char *name; } device_found_map[] = { { DEVICE_FOUND_UDEV, "found-udev" }, { DEVICE_FOUND_MOUNT, "found-mount" }, { DEVICE_FOUND_SWAP, "found-swap" }, }; static int device_found_to_string_many(DeviceFound flags, char **ret) { _cleanup_free_ char *s = NULL; unsigned i; assert(ret); for (i = 0; i < ELEMENTSOF(device_found_map); i++) { if (!FLAGS_SET(flags, device_found_map[i].flag)) continue; if (!strextend_with_separator(&s, ",", device_found_map[i].name, NULL)) return -ENOMEM; } *ret = TAKE_PTR(s); return 0; } static int device_found_from_string_many(const char *name, DeviceFound *ret) { DeviceFound flags = 0; int r; assert(ret); for (;;) { _cleanup_free_ char *word = NULL; DeviceFound f = 0; unsigned i; r = extract_first_word(&name, &word, ",", 0); if (r < 0) return r; if (r == 0) break; for (i = 0; i < ELEMENTSOF(device_found_map); i++) if (streq(word, device_found_map[i].name)) { f = device_found_map[i].flag; break; } if (f == 0) return -EINVAL; flags |= f; } *ret = flags; return 0; } static int device_serialize(Unit *u, FILE *f, FDSet *fds) { _cleanup_free_ char *s = NULL; Device *d = DEVICE(u); assert(u); assert(f); assert(fds); unit_serialize_item(u, f, "state", device_state_to_string(d->state)); if (device_found_to_string_many(d->found, &s) >= 0) unit_serialize_item(u, f, "found", s); return 0; } static int device_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) { Device *d = DEVICE(u); int r; 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, ignoring: %s", value); else d->deserialized_state = state; } else if (streq(key, "found")) { r = device_found_from_string_many(value, &d->deserialized_found); if (r < 0) log_unit_debug_errno(u, r, "Failed to parse found value, ignoring: %s", value); } 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); _cleanup_free_ char *s = NULL; assert(d); (void) device_found_to_string_many(d->found, &s); fprintf(f, "%sDevice State: %s\n" "%sSysfs Path: %s\n" "%sFound: %s\n", prefix, device_state_to_string(d->state), prefix, strna(d->sysfs), prefix, strna(s)); } _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); if (!j) return log_oom(); r = unit_set_description(u, j); } else r = unit_set_description(u, model); } else r = unit_set_description(u, path); if (r < 0) return log_unit_error_errno(u, r, "Failed to set device description: %m"); return 0; } static int device_add_udev_wants(Unit *u, struct udev_device *dev) { const char *wants, *property; int r; 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; for (;;) { _cleanup_free_ char *word = NULL, *k = NULL; r = extract_first_word(&wants, &word, NULL, EXTRACT_QUOTES); if (r == 0) return 0; if (r == -ENOMEM) return log_oom(); if (r < 0) return log_unit_error_errno(u, r, "Failed to parse property %s with value %s: %m", property, wants); if (unit_name_is_valid(word, UNIT_NAME_TEMPLATE) && DEVICE(u)->sysfs) { _cleanup_free_ char *escaped = NULL; /* If the unit name is specified as template, then automatically fill in the sysfs path of the * device as instance name, properly escaped. */ r = unit_name_path_escape(DEVICE(u)->sysfs, &escaped); if (r < 0) return log_unit_error_errno(u, r, "Failed to escape %s: %m", DEVICE(u)->sysfs); r = unit_name_replace_instance(word, escaped, &k); if (r < 0) return log_unit_error_errno(u, r, "Failed to build %s instance of template %s: %m", escaped, word); } else { /* If this is not a template, then let's mangle it so, that it becomes a valid unit name. */ r = unit_name_mangle(word, UNIT_NAME_MANGLE_WARN, &k); if (r < 0) return log_unit_error_errno(u, r, "Failed to mangle unit name \"%s\": %m", word); } r = unit_add_dependency_by_name(u, UNIT_WANTS, k, NULL, true, UNIT_DEPENDENCY_UDEV); if (r < 0) return log_unit_error_errno(u, r, "Failed to add Wants= dependency: %m"); } } static bool device_is_bound_by_mounts(Device *d, struct udev_device *dev) { const char *bound_by; int r; assert(d); assert(dev); bound_by = udev_device_get_property_value(dev, "SYSTEMD_MOUNT_DEVICE_BOUND"); if (bound_by) { r = parse_boolean(bound_by); if (r < 0) log_warning_errno(r, "Failed to parse SYSTEMD_MOUNT_DEVICE_BOUND='%s' udev property of %s, ignoring: %m", bound_by, strna(d->sysfs)); d->bind_mounts = r > 0; } else d->bind_mounts = false; return d->bind_mounts; } static void device_upgrade_mount_deps(Unit *u) { Unit *other; Iterator i; void *v; int r; /* Let's upgrade Requires= to BindsTo= on us. (Used when SYSTEMD_MOUNT_DEVICE_BOUND is set) */ HASHMAP_FOREACH_KEY(v, other, u->dependencies[UNIT_REQUIRED_BY], i) { if (other->type != UNIT_MOUNT) continue; r = unit_add_dependency(other, UNIT_BINDS_TO, u, true, UNIT_DEPENDENCY_UDEV); if (r < 0) log_unit_warning_errno(u, r, "Failed to add BindsTo= dependency between device and mount unit, ignoring: %m"); } } 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) { log_debug("Couldn't get syspath from udev device, ignoring."); 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) { /* 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. When the device is * plugged the sysfs might not be initialized yet, as we serialize the device's state but do not * serialize the sysfs path across reloads/reexecs. Hence, when coming back from a reload/restart we * might have the state valid, but not the sysfs path. Hence, let's filter out conflicting devices, but * let's accept devices in any state with no sysfs path set. */ if (DEVICE(u)->state == DEVICE_PLUGGED && DEVICE(u)->sysfs && sysfs && !path_equal(DEVICE(u)->sysfs, sysfs)) { log_unit_debug(u, "Device %s appeared twice with different sysfs paths %s and %s, ignoring the latter.", e, DEVICE(u)->sysfs, sysfs); return -EEXIST; } delete = false; /* Let's remove all dependencies generated due to udev properties. We'll readd whatever is configured * now below. */ unit_remove_dependencies(u, UNIT_DEPENDENCY_UDEV); } else { delete = true; r = unit_new_for_name(m, sizeof(Device), e, &u); if (r < 0) { log_error_errno(r, "Failed to allocate device unit %s: %m", e); goto fail; } unit_add_to_load_queue(u); } /* 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) { log_error_errno(r, "Failed to set sysfs path %s for device unit %s: %m", sysfs, e); 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); } /* So the user wants the mount units to be bound to the device but a mount unit might has been seen by systemd * before the device appears on its radar. In this case the device unit is partially initialized and includes * the deps on the mount unit but at that time the "bind mounts" flag wasn't not present. Fix this up now. */ if (dev && device_is_bound_by_mounts(DEVICE(u), dev)) device_upgrade_mount_deps(u); /* 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: 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_SET(p, "/dev/block/", "/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"); for (;;) { _cleanup_free_ char *word = NULL; r = extract_first_word(&alias, &word, NULL, EXTRACT_QUOTES); if (r == 0) break; if (r == -ENOMEM) return log_oom(); if (r < 0) return log_warning_errno(r, "Failed to add parse SYSTEMD_ALIAS for %s: %m", sysfs); if (!path_is_absolute(word)) log_warning("SYSTEMD_ALIAS for %s is not an absolute path, ignoring: %s", sysfs, word); else if (!path_is_normalized(word)) log_warning("SYSTEMD_ALIAS for %s is not a normalized path, ignoring: %s", sysfs, word); else (void) device_setup_unit(m, dev, word, false); } return 0; } static void device_found_changed(Device *d, DeviceFound previous, DeviceFound now) { assert(d); /* Didn't exist before, but does now? if so, generate a new invocation ID for it */ if (previous == DEVICE_NOT_FOUND && now != DEVICE_NOT_FOUND) (void) unit_acquire_invocation_id(UNIT(d)); if (FLAGS_SET(now, DEVICE_FOUND_UDEV)) /* When the device is known to udev we consider it plugged. */ device_set_state(d, DEVICE_PLUGGED); else if (now != DEVICE_NOT_FOUND && !FLAGS_SET(previous, DEVICE_FOUND_UDEV)) /* 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 void device_update_found_one(Device *d, DeviceFound found, DeviceFound mask) { assert(d); if (MANAGER_IS_RUNNING(UNIT(d)->manager)) { DeviceFound n, previous; /* When we are already running, then apply the new mask right-away, and trigger state changes * right-away */ n = (d->found & ~mask) | (found & mask); if (n == d->found) return; previous = d->found; d->found = n; device_found_changed(d, previous, n); } else /* We aren't running yet, let's apply the new mask to the shadow variable instead, which we'll apply as * soon as we catch-up with the state. */ d->enumerated_found = (d->enumerated_found & ~mask) | (found & mask); } static void device_update_found_by_sysfs(Manager *m, const char *sysfs, DeviceFound found, DeviceFound mask) { Device *d, *l, *n; assert(m); assert(sysfs); if (mask == 0) return; l = hashmap_get(m->devices_by_sysfs, sysfs); LIST_FOREACH_SAFE(same_sysfs, d, n, l) device_update_found_one(d, found, mask); } static int device_update_found_by_name(Manager *m, const char *path, DeviceFound found, DeviceFound mask) { _cleanup_free_ char *e = NULL; Unit *u; int r; assert(m); assert(path); if (mask == 0) 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), found, mask); 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; _cleanup_set_free_ Set *set = NULL; 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) return r; } LIST_FOREACH_BEFORE(same_sysfs, other, d) { r = set_put(set, other); if (r < 0) return r; } *_set = TAKE_PTR(set); return 1; } static void device_shutdown(Manager *m) { assert(m); m->udev_event_source = sd_event_source_unref(m->udev_event_source); m->udev_monitor = udev_monitor_unref(m->udev_monitor); m->devices_by_sysfs = hashmap_free(m->devices_by_sysfs); } static void device_enumerate(Manager *m) { _cleanup_(udev_enumerate_unrefp) 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_error_errno(errno, "Failed to allocate udev monitor: %m"); 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_error_errno(errno, "Failed to alloacte udev enumerator: %m"); 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_unrefp) 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) { if (errno == ENOMEM) { log_oom(); goto fail; } /* If we can't create a device, don't bother, it probably just disappeared. */ log_debug_errno(errno, "Failed to create udev device object for %s: %m", sysfs); continue; } if (!device_is_ready(dev)) continue; (void) device_process_new(m, dev); device_update_found_by_sysfs(m, sysfs, DEVICE_FOUND_UDEV, DEVICE_FOUND_UDEV); } return; fail: device_shutdown(m); } static void device_propagate_reload_by_sysfs(Manager *m, const char *sysfs) { Device *d, *l, *n; int r; assert(m); assert(sysfs); l = hashmap_get(m->devices_by_sysfs, sysfs); LIST_FOREACH_SAFE(same_sysfs, d, n, l) { if (d->state == DEVICE_DEAD) continue; r = manager_propagate_reload(m, UNIT(d), JOB_REPLACE, NULL); if (r < 0) log_warning_errno(r, "Failed to propagate reload, ignoring: %m"); } } static int device_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) { _cleanup_(udev_device_unrefp) 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_below(&limit)) log_warning("Failed to get udev event"); 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, "change")) device_propagate_reload_by_sysfs(m, sysfs); /* A change event can signal that a device is becoming ready, in particular if * the device is using the SYSTEMD_READY logic in udev * so we need to reach the else block of the follwing if, even for change events */ if (streq(action, "remove")) { r = swap_process_device_remove(m, dev); if (r < 0) log_warning_errno(r, "Failed to process swap device remove event, ignoring: %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, 0, DEVICE_FOUND_UDEV|DEVICE_FOUND_MOUNT|DEVICE_FOUND_SWAP); } else if (device_is_ready(dev)) { (void) device_process_new(m, dev); r = swap_process_device_new(m, dev); if (r < 0) log_warning_errno(r, "Failed to process swap device new event, ignoring: %m"); manager_dispatch_load_queue(m); /* The device is found now, set the udev found bit */ device_update_found_by_sysfs(m, sysfs, DEVICE_FOUND_UDEV, DEVICE_FOUND_UDEV); } 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, 0, DEVICE_FOUND_UDEV); } 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; } static int validate_node(Manager *m, const char *node, struct udev_device **ret) { struct stat st; int r; assert(m); assert(node); assert(ret); /* Validates a device node that showed up in /proc/swaps or /proc/self/mountinfo if it makes sense for us to * track. Note that this validator is fine within missing device nodes, but not with badly set up ones! */ if (!path_startswith(node, "/dev")) { *ret = NULL; return 0; /* bad! */ } if (stat(node, &st) < 0) { if (errno != ENOENT) return log_error_errno(errno, "Failed to stat() device node file %s: %m", node); *ret = NULL; return 1; /* good! (though missing) */ } else { _cleanup_(udev_device_unrefp) struct udev_device *dev = NULL; r = udev_device_new_from_stat_rdev(m->udev, &st, &dev); if (r == -ENOENT) { *ret = NULL; return 1; /* good! (though missing) */ } else if (r == -ENOTTY) { *ret = NULL; return 0; /* bad! (not a device node but some other kind of file system node) */ } else if (r < 0) return log_error_errno(r, "Failed to get udev device from devnum %u:%u: %m", major(st.st_rdev), minor(st.st_rdev)); *ret = TAKE_PTR(dev); return 1; /* good! */ } } void device_found_node(Manager *m, const char *node, DeviceFound found, DeviceFound mask) { int r; assert(m); assert(node); if (!device_supported()) return; if (mask == 0) return; /* 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. * * This takes a pair of DeviceFound flags parameters. The 'mask' parameter is a bit mask that indicates which * bits of 'found' to copy into the per-device DeviceFound flags field. Thus, this function may be used to set * and unset individual bits in a single call, while merging partially with previous state. */ if ((found & mask) != 0) { _cleanup_(udev_device_unrefp) struct udev_device *dev = NULL; /* 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. But first, let's validate if * everything is alright with the device node. */ r = validate_node(m, node, &dev); if (r <= 0) return; /* Don't create a device unit for this if the device node is borked. */ (void) device_setup_unit(m, dev, node, false); } /* Update the device unit's state, should it exist */ (void) device_update_found_by_name(m, node, found, mask); } bool device_shall_be_bound_by(Unit *device, Unit *u) { assert(device); assert(u); if (u->type != UNIT_MOUNT) return false; return DEVICE(device)->bind_mounts; } const UnitVTable device_vtable = { .object_size = sizeof(Device), .sections = "Unit\0" "Device\0" "Install\0", .gc_jobs = true, .init = device_init, .done = device_done, .load = unit_load_fragment_and_dropin_optional, .coldplug = device_coldplug, .catchup = device_catchup, .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.", }, }, };