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-rw-r--r--src/libcore/path.c784
1 files changed, 784 insertions, 0 deletions
diff --git a/src/libcore/path.c b/src/libcore/path.c
new file mode 100644
index 0000000000..0dd0d375d8
--- /dev/null
+++ b/src/libcore/path.c
@@ -0,0 +1,784 @@
+/***
+ 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 <sys/inotify.h>
+#include <unistd.h>
+
+#include "bus-error.h"
+#include "bus-util.h"
+#include "dbus-path.h"
+#include "fd-util.h"
+#include "fs-util.h"
+#include "glob-util.h"
+#include "macro.h"
+#include "mkdir.h"
+#include "path.h"
+#include "special.h"
+#include "stat-util.h"
+#include "string-table.h"
+#include "string-util.h"
+#include "unit-name.h"
+#include "unit.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';
+
+ (void) 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);
+
+ if (!UNIT(p)->default_dependencies)
+ return 0;
+
+ r = unit_add_dependency_by_name(UNIT(p), UNIT_BEFORE, SPECIAL_PATHS_TARGET, NULL, true);
+ if (r < 0)
+ return r;
+
+ if (MANAGER_IS_SYSTEM(UNIT(p)->manager)) {
+ 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;
+
+ 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_unit_debug(UNIT(p), "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_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+ Unit *trigger;
+ int r;
+
+ assert(p);
+
+ /* Don't start job if we are supposed to go down */
+ if (unit_stop_pending(UNIT(p)))
+ return;
+
+ trigger = UNIT_TRIGGER(UNIT(p));
+ if (!trigger) {
+ log_unit_error(UNIT(p), "Unit to trigger vanished.");
+ path_enter_dead(p, PATH_FAILURE_RESOURCES);
+ return;
+ }
+
+ r = manager_add_job(UNIT(p)->manager, JOB_START, trigger, JOB_REPLACE, &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);
+ Unit *trigger;
+ int r;
+
+ assert(p);
+ assert(p->state == PATH_DEAD || p->state == PATH_FAILED);
+
+ trigger = UNIT_TRIGGER(u);
+ if (!trigger || trigger->load_state != UNIT_LOADED) {
+ log_unit_error(u, "Refusing to start, unit to trigger not loaded.");
+ return -ENOENT;
+ }
+
+ r = unit_start_limit_test(u);
+ if (r < 0) {
+ path_enter_dead(p, PATH_FAILURE_START_LIMIT_HIT);
+ return r;
+ }
+
+ 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_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",
+ [PATH_FAILURE_START_LIMIT_HIT] = "start-limit-hit",
+};
+
+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_vtable = bus_path_vtable
+};