/*-*- 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 <sys/inotify.h> #include <sys/epoll.h> #include <errno.h> #include <unistd.h> #include "unit.h" #include "unit-name.h" #include "path.h" #include "mkdir.h" #include "dbus-path.h" #include "special.h" #include "macro.h" #include "bus-util.h" #include "bus-error.h" static const UnitActiveState state_translation_table[_PATH_STATE_MAX] = { [PATH_DEAD] = UNIT_INACTIVE, [PATH_WAITING] = UNIT_ACTIVE, [PATH_RUNNING] = UNIT_ACTIVE, [PATH_FAILED] = UNIT_FAILED }; static int path_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata); int path_spec_watch(PathSpec *s, sd_event_io_handler_t handler) { static const int flags_table[_PATH_TYPE_MAX] = { [PATH_EXISTS] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB, [PATH_EXISTS_GLOB] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB, [PATH_CHANGED] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CLOSE_WRITE|IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO, [PATH_MODIFIED] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CLOSE_WRITE|IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO|IN_MODIFY, [PATH_DIRECTORY_NOT_EMPTY] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CREATE|IN_MOVED_TO }; bool exists = false; char *slash, *oldslash = NULL; int r; assert(s); assert(s->unit); assert(handler); path_spec_unwatch(s); s->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC); if (s->inotify_fd < 0) { r = -errno; goto fail; } r = sd_event_add_io(s->unit->manager->event, &s->event_source, s->inotify_fd, EPOLLIN, handler, s); if (r < 0) goto fail; (void) sd_event_source_set_description(s->event_source, "path"); /* This assumes the path was passed through path_kill_slashes()! */ for (slash = strchr(s->path, '/'); ; slash = strchr(slash+1, '/')) { char *cut = NULL; int flags; char tmp; if (slash) { cut = slash + (slash == s->path); tmp = *cut; *cut = '\0'; flags = IN_MOVE_SELF | IN_DELETE_SELF | IN_ATTRIB | IN_CREATE | IN_MOVED_TO; } else flags = flags_table[s->type]; r = inotify_add_watch(s->inotify_fd, s->path, flags); if (r < 0) { if (errno == EACCES || errno == ENOENT) { if (cut) *cut = tmp; break; } r = log_warning_errno(errno, "Failed to add watch on %s: %s", s->path, errno == ENOSPC ? "too many watches" : strerror(-r)); if (cut) *cut = tmp; goto fail; } else { exists = true; /* Path exists, we don't need to watch parent too closely. */ if (oldslash) { char *cut2 = oldslash + (oldslash == s->path); char tmp2 = *cut2; *cut2 = '\0'; inotify_add_watch(s->inotify_fd, s->path, IN_MOVE_SELF); /* Error is ignored, the worst can happen is we get spurious events. */ *cut2 = tmp2; } } if (cut) *cut = tmp; if (slash) oldslash = slash; else { /* whole path has been iterated over */ s->primary_wd = r; break; } } if (!exists) { r = log_error_errno(errno, "Failed to add watch on any of the components of %s: %m", s->path); /* either EACCESS or ENOENT */ goto fail; } return 0; fail: path_spec_unwatch(s); return r; } void path_spec_unwatch(PathSpec *s) { assert(s); s->event_source = sd_event_source_unref(s->event_source); s->inotify_fd = safe_close(s->inotify_fd); } int path_spec_fd_event(PathSpec *s, uint32_t revents) { union inotify_event_buffer buffer; struct inotify_event *e; ssize_t l; int r = 0; if (revents != EPOLLIN) { log_error("Got invalid poll event on inotify."); return -EINVAL; } l = read(s->inotify_fd, &buffer, sizeof(buffer)); if (l < 0) { if (errno == EAGAIN || errno == EINTR) return 0; return log_error_errno(errno, "Failed to read inotify event: %m"); } FOREACH_INOTIFY_EVENT(e, buffer, l) { if ((s->type == PATH_CHANGED || s->type == PATH_MODIFIED) && s->primary_wd == e->wd) r = 1; } return r; } static bool path_spec_check_good(PathSpec *s, bool initial) { bool good = false; switch (s->type) { case PATH_EXISTS: good = access(s->path, F_OK) >= 0; break; case PATH_EXISTS_GLOB: good = glob_exists(s->path) > 0; break; case PATH_DIRECTORY_NOT_EMPTY: { int k; k = dir_is_empty(s->path); good = !(k == -ENOENT || k > 0); break; } case PATH_CHANGED: case PATH_MODIFIED: { bool b; b = access(s->path, F_OK) >= 0; good = !initial && b != s->previous_exists; s->previous_exists = b; break; } default: ; } return good; } static void path_spec_mkdir(PathSpec *s, mode_t mode) { int r; if (s->type == PATH_EXISTS || s->type == PATH_EXISTS_GLOB) return; r = mkdir_p_label(s->path, mode); if (r < 0) log_warning_errno(r, "mkdir(%s) failed: %m", s->path); } static void path_spec_dump(PathSpec *s, FILE *f, const char *prefix) { fprintf(f, "%s%s: %s\n", prefix, path_type_to_string(s->type), s->path); } void path_spec_done(PathSpec *s) { assert(s); assert(s->inotify_fd == -1); free(s->path); } static void path_init(Unit *u) { Path *p = PATH(u); assert(u); assert(u->load_state == UNIT_STUB); p->directory_mode = 0755; } void path_free_specs(Path *p) { PathSpec *s; assert(p); while ((s = p->specs)) { path_spec_unwatch(s); LIST_REMOVE(spec, p->specs, s); path_spec_done(s); free(s); } } static void path_done(Unit *u) { Path *p = PATH(u); assert(p); path_free_specs(p); } static int path_add_mount_links(Path *p) { PathSpec *s; int r; assert(p); LIST_FOREACH(spec, s, p->specs) { r = unit_require_mounts_for(UNIT(p), s->path); if (r < 0) return r; } return 0; } static int path_verify(Path *p) { assert(p); if (UNIT(p)->load_state != UNIT_LOADED) return 0; if (!p->specs) { log_unit_error(UNIT(p), "Path unit lacks path setting. Refusing."); return -EINVAL; } return 0; } static int path_add_default_dependencies(Path *p) { int r; assert(p); r = unit_add_dependency_by_name(UNIT(p), UNIT_BEFORE, SPECIAL_PATHS_TARGET, NULL, true); if (r < 0) return r; if (UNIT(p)->manager->running_as == MANAGER_SYSTEM) { r = unit_add_two_dependencies_by_name(UNIT(p), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, NULL, true); if (r < 0) return r; } return unit_add_two_dependencies_by_name(UNIT(p), UNIT_BEFORE, UNIT_CONFLICTS, SPECIAL_SHUTDOWN_TARGET, NULL, true); } static int path_load(Unit *u) { Path *p = PATH(u); int r; assert(u); assert(u->load_state == UNIT_STUB); r = unit_load_fragment_and_dropin(u); if (r < 0) return r; if (u->load_state == UNIT_LOADED) { if (set_isempty(u->dependencies[UNIT_TRIGGERS])) { Unit *x; r = unit_load_related_unit(u, ".service", &x); if (r < 0) return r; r = unit_add_two_dependencies(u, UNIT_BEFORE, UNIT_TRIGGERS, x, true); if (r < 0) return r; } r = path_add_mount_links(p); if (r < 0) return r; if (UNIT(p)->default_dependencies) { r = path_add_default_dependencies(p); if (r < 0) return r; } } return path_verify(p); } static void path_dump(Unit *u, FILE *f, const char *prefix) { Path *p = PATH(u); Unit *trigger; PathSpec *s; assert(p); assert(f); trigger = UNIT_TRIGGER(u); fprintf(f, "%sPath State: %s\n" "%sResult: %s\n" "%sUnit: %s\n" "%sMakeDirectory: %s\n" "%sDirectoryMode: %04o\n", prefix, path_state_to_string(p->state), prefix, path_result_to_string(p->result), prefix, trigger ? trigger->id : "n/a", prefix, yes_no(p->make_directory), prefix, p->directory_mode); LIST_FOREACH(spec, s, p->specs) path_spec_dump(s, f, prefix); } static void path_unwatch(Path *p) { PathSpec *s; assert(p); LIST_FOREACH(spec, s, p->specs) path_spec_unwatch(s); } static int path_watch(Path *p) { int r; PathSpec *s; assert(p); LIST_FOREACH(spec, s, p->specs) { r = path_spec_watch(s, path_dispatch_io); if (r < 0) return r; } return 0; } static void path_set_state(Path *p, PathState state) { PathState old_state; assert(p); old_state = p->state; p->state = state; if (state != PATH_WAITING && (state != PATH_RUNNING || p->inotify_triggered)) path_unwatch(p); if (state != old_state) log_debug("Changed %s -> %s", path_state_to_string(old_state), path_state_to_string(state)); unit_notify(UNIT(p), state_translation_table[old_state], state_translation_table[state], true); } static void path_enter_waiting(Path *p, bool initial, bool recheck); static int path_coldplug(Unit *u) { Path *p = PATH(u); assert(p); assert(p->state == PATH_DEAD); if (p->deserialized_state != p->state) { if (p->deserialized_state == PATH_WAITING || p->deserialized_state == PATH_RUNNING) path_enter_waiting(p, true, true); else path_set_state(p, p->deserialized_state); } return 0; } static void path_enter_dead(Path *p, PathResult f) { assert(p); if (f != PATH_SUCCESS) p->result = f; path_set_state(p, p->result != PATH_SUCCESS ? PATH_FAILED : PATH_DEAD); } static void path_enter_running(Path *p) { _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL; int r; assert(p); /* Don't start job if we are supposed to go down */ if (unit_stop_pending(UNIT(p))) return; r = manager_add_job(UNIT(p)->manager, JOB_START, UNIT_TRIGGER(UNIT(p)), JOB_REPLACE, true, &error, NULL); if (r < 0) goto fail; p->inotify_triggered = false; r = path_watch(p); if (r < 0) goto fail; path_set_state(p, PATH_RUNNING); return; fail: log_unit_warning(UNIT(p), "Failed to queue unit startup job: %s", bus_error_message(&error, r)); path_enter_dead(p, PATH_FAILURE_RESOURCES); } static bool path_check_good(Path *p, bool initial) { PathSpec *s; bool good = false; assert(p); LIST_FOREACH(spec, s, p->specs) { good = path_spec_check_good(s, initial); if (good) break; } return good; } static void path_enter_waiting(Path *p, bool initial, bool recheck) { int r; if (recheck) if (path_check_good(p, initial)) { log_unit_debug(UNIT(p), "Got triggered."); path_enter_running(p); return; } r = path_watch(p); if (r < 0) goto fail; /* Hmm, so now we have created inotify watches, but the file * might have appeared/been removed by now, so we must * recheck */ if (recheck) if (path_check_good(p, false)) { log_unit_debug(UNIT(p), "Got triggered."); path_enter_running(p); return; } path_set_state(p, PATH_WAITING); return; fail: log_unit_warning_errno(UNIT(p), r, "Failed to enter waiting state: %m"); path_enter_dead(p, PATH_FAILURE_RESOURCES); } static void path_mkdir(Path *p) { PathSpec *s; assert(p); if (!p->make_directory) return; LIST_FOREACH(spec, s, p->specs) path_spec_mkdir(s, p->directory_mode); } static int path_start(Unit *u) { Path *p = PATH(u); assert(p); assert(p->state == PATH_DEAD || p->state == PATH_FAILED); if (UNIT_TRIGGER(u)->load_state != UNIT_LOADED) return -ENOENT; path_mkdir(p); p->result = PATH_SUCCESS; path_enter_waiting(p, true, true); return 1; } static int path_stop(Unit *u) { Path *p = PATH(u); assert(p); assert(p->state == PATH_WAITING || p->state == PATH_RUNNING); path_enter_dead(p, PATH_SUCCESS); return 1; } static int path_serialize(Unit *u, FILE *f, FDSet *fds) { Path *p = PATH(u); assert(u); assert(f); assert(fds); unit_serialize_item(u, f, "state", path_state_to_string(p->state)); unit_serialize_item(u, f, "result", path_result_to_string(p->result)); return 0; } static int path_deserialize_item(Unit *u, const char *key, const char *value, FDSet *fds) { Path *p = PATH(u); assert(u); assert(key); assert(value); assert(fds); if (streq(key, "state")) { PathState state; state = path_state_from_string(value); if (state < 0) log_unit_debug(u, "Failed to parse state value: %s", value); else p->deserialized_state = state; } else if (streq(key, "result")) { PathResult f; f = path_result_from_string(value); if (f < 0) log_unit_debug(u, "Failed to parse result value: %s", value); else if (f != PATH_SUCCESS) p->result = f; } else log_unit_debug(u, "Unknown serialization key: %s", key); return 0; } _pure_ static UnitActiveState path_active_state(Unit *u) { assert(u); return state_translation_table[PATH(u)->state]; } _pure_ static const char *path_sub_state_to_string(Unit *u) { assert(u); return path_state_to_string(PATH(u)->state); } static int path_dispatch_io(sd_event_source *source, int fd, uint32_t revents, void *userdata) { PathSpec *s = userdata; Path *p; int changed; assert(s); assert(s->unit); assert(fd >= 0); p = PATH(s->unit); if (p->state != PATH_WAITING && p->state != PATH_RUNNING) return 0; /* log_debug("inotify wakeup on %s.", u->id); */ LIST_FOREACH(spec, s, p->specs) if (path_spec_owns_inotify_fd(s, fd)) break; if (!s) { log_error("Got event on unknown fd."); goto fail; } changed = path_spec_fd_event(s, revents); if (changed < 0) goto fail; /* If we are already running, then remember that one event was * dispatched so that we restart the service only if something * actually changed on disk */ p->inotify_triggered = true; if (changed) path_enter_running(p); else path_enter_waiting(p, false, true); return 0; fail: path_enter_dead(p, PATH_FAILURE_RESOURCES); return 0; } static void path_trigger_notify(Unit *u, Unit *other) { Path *p = PATH(u); assert(u); assert(other); /* Invoked whenever the unit we trigger changes state or gains * or loses a job */ if (other->load_state != UNIT_LOADED) return; if (p->state == PATH_RUNNING && UNIT_IS_INACTIVE_OR_FAILED(unit_active_state(other))) { log_unit_debug(UNIT(p), "Got notified about unit deactivation."); /* Hmm, so inotify was triggered since the * last activation, so I guess we need to * recheck what is going on. */ path_enter_waiting(p, false, p->inotify_triggered); } } static void path_reset_failed(Unit *u) { Path *p = PATH(u); assert(p); if (p->state == PATH_FAILED) path_set_state(p, PATH_DEAD); p->result = PATH_SUCCESS; } static const char* const path_state_table[_PATH_STATE_MAX] = { [PATH_DEAD] = "dead", [PATH_WAITING] = "waiting", [PATH_RUNNING] = "running", [PATH_FAILED] = "failed" }; DEFINE_STRING_TABLE_LOOKUP(path_state, PathState); static const char* const path_type_table[_PATH_TYPE_MAX] = { [PATH_EXISTS] = "PathExists", [PATH_EXISTS_GLOB] = "PathExistsGlob", [PATH_DIRECTORY_NOT_EMPTY] = "DirectoryNotEmpty", [PATH_CHANGED] = "PathChanged", [PATH_MODIFIED] = "PathModified", }; DEFINE_STRING_TABLE_LOOKUP(path_type, PathType); static const char* const path_result_table[_PATH_RESULT_MAX] = { [PATH_SUCCESS] = "success", [PATH_FAILURE_RESOURCES] = "resources", }; DEFINE_STRING_TABLE_LOOKUP(path_result, PathResult); const UnitVTable path_vtable = { .object_size = sizeof(Path), .sections = "Unit\0" "Path\0" "Install\0", .init = path_init, .done = path_done, .load = path_load, .coldplug = path_coldplug, .dump = path_dump, .start = path_start, .stop = path_stop, .serialize = path_serialize, .deserialize_item = path_deserialize_item, .active_state = path_active_state, .sub_state_to_string = path_sub_state_to_string, .trigger_notify = path_trigger_notify, .reset_failed = path_reset_failed, .bus_interface = "org.freedesktop.systemd1.Path", .bus_vtable = bus_path_vtable };