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authorLennart Poettering <lennart@poettering.net>2010-05-24 05:25:33 +0200
committerLennart Poettering <lennart@poettering.net>2010-05-24 05:25:33 +0200
commit01f78473b104d28db0fa813414092bc6358ae521 (patch)
treedbc1a63d818c7420ee2a50cbd205ae90b0c7185d /src/path.c
parent871d7de47c13ee6cd78b8eefdf9128be3c740ac0 (diff)
path: add .path unit type for monitoring files
Diffstat (limited to 'src/path.c')
-rw-r--r--src/path.c578
1 files changed, 578 insertions, 0 deletions
diff --git a/src/path.c b/src/path.c
new file mode 100644
index 0000000000..b40a8297ff
--- /dev/null
+++ b/src/path.c
@@ -0,0 +1,578 @@
+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+ 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 General Public License as published by
+ the Free Software Foundation; either version 2 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
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <sys/inotify.h>
+#include <sys/epoll.h>
+#include <sys/ioctl.h>
+#include <errno.h>
+#include <unistd.h>
+
+#include "unit.h"
+#include "unit-name.h"
+#include "path.h"
+#include "dbus-path.h"
+
+static const UnitActiveState state_translation_table[_PATH_STATE_MAX] = {
+ [PATH_DEAD] = UNIT_INACTIVE,
+ [PATH_WAITING] = UNIT_ACTIVE,
+ [PATH_RUNNING] = UNIT_ACTIVE,
+ [PATH_MAINTAINANCE] = UNIT_INACTIVE
+};
+
+static void path_done(Unit *u) {
+ Path *p = PATH(u);
+ PathSpec *s;
+
+ assert(p);
+
+ while ((s = p->specs)) {
+ LIST_REMOVE(PathSpec, spec, p->specs, s);
+ free(s);
+ }
+}
+
+int path_add_one_mount_link(Path *p, Mount *m) {
+ PathSpec *s;
+ int r;
+
+ assert(p);
+ assert(m);
+
+ if (p->meta.load_state != UNIT_LOADED ||
+ m->meta.load_state != UNIT_LOADED)
+ return 0;
+
+ LIST_FOREACH(spec, s, p->specs) {
+
+ if (!path_startswith(s->path, m->where))
+ continue;
+
+ if ((r = unit_add_dependency(UNIT(m), UNIT_BEFORE, UNIT(p), true)) < 0)
+ return r;
+
+ if ((r = unit_add_dependency(UNIT(p), UNIT_REQUIRES, UNIT(m), true)) < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int path_add_mount_links(Path *p) {
+ Meta *other;
+ int r;
+
+ assert(p);
+
+ LIST_FOREACH(units_per_type, other, p->meta.manager->units_per_type[UNIT_MOUNT])
+ if ((r = path_add_one_mount_link(p, (Mount*) other)) < 0)
+ return r;
+
+ return 0;
+}
+
+static int path_verify(Path *p) {
+ assert(p);
+
+ if (UNIT(p)->meta.load_state != UNIT_LOADED)
+ return 0;
+
+ if (!p->specs) {
+ log_error("%s lacks path setting. Refusing.", p->meta.id);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static int path_load(Unit *u) {
+ Path *p = PATH(u);
+ int r;
+
+ assert(u);
+ assert(u->meta.load_state == UNIT_STUB);
+
+ if ((r = unit_load_fragment_and_dropin(u)) < 0)
+ return r;
+
+ if (u->meta.load_state == UNIT_LOADED) {
+
+ if (!p->unit)
+ if ((r = unit_load_related_unit(u, ".service", &p->unit)))
+ return r;
+
+ if ((r = unit_add_dependency(u, UNIT_BEFORE, p->unit, true)) < 0)
+ return r;
+
+ if ((r = path_add_mount_links(p)) < 0)
+ return r;
+ }
+
+ return path_verify(p);
+}
+
+static void path_dump(Unit *u, FILE *f, const char *prefix) {
+ Path *p = PATH(u);
+ const char *prefix2;
+ char *p2;
+ PathSpec *s;
+
+ p2 = strappend(prefix, "\t");
+ prefix2 = p2 ? p2 : prefix;
+
+ fprintf(f,
+ "%sPath State: %s\n"
+ "%sUnit: %s\n",
+ prefix, path_state_to_string(p->state),
+ prefix, p->unit->meta.id);
+
+ LIST_FOREACH(spec, s, p->specs)
+ fprintf(f,
+ "%s%s: %s\n",
+ prefix,
+ path_type_to_string(s->type),
+ s->path);
+
+ free(p2);
+}
+
+static void path_unwatch_one(Path *p, PathSpec *s) {
+
+ if (s->inotify_fd < 0)
+ return;
+
+ unit_unwatch_fd(UNIT(p), &s->watch);
+
+ close_nointr_nofail(s->inotify_fd);
+ s->inotify_fd = -1;
+}
+
+static int path_watch_one(Path *p, PathSpec *s) {
+ static const int flags_table[_PATH_TYPE_MAX] = {
+ [PATH_EXISTS] = IN_DELETE_SELF|IN_MOVE_SELF,
+ [PATH_CHANGED] = IN_DELETE_SELF|IN_MOVE_SELF|IN_ATTRIB|IN_CLOSE_WRITE|IN_CREATE|IN_DELETE|IN_MOVED_FROM|IN_MOVED_TO,
+ [PATH_DIRECTORY_NOT_EMPTY] = IN_DELETE_SELF|IN_MOVE_SELF|IN_CREATE|IN_MOVED_TO
+ };
+
+ bool exists = false;
+ char *k;
+ int r;
+
+ assert(p);
+ assert(s);
+
+ path_unwatch_one(p, s);
+
+ if (!(k = strdup(s->path)))
+ return -ENOMEM;
+
+ if ((s->inotify_fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC)) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ if (unit_watch_fd(UNIT(p), s->inotify_fd, EPOLLIN, &s->watch) < 0) {
+ r = -errno;
+ goto fail;
+ }
+
+ if ((s->primary_wd = inotify_add_watch(s->inotify_fd, k, flags_table[s->type])) >= 0)
+ exists = true;
+
+ for (;;) {
+ int flags;
+ char *slash;
+
+ /* This assumes the path was passed through path_kill_slashes()! */
+ if (!(slash = strrchr(k, '/')))
+ break;
+
+ *slash = 0;
+
+ flags = IN_DELETE_SELF|IN_MOVE_SELF;
+ if (!exists)
+ flags |= IN_CREATE | IN_MOVED_TO | IN_ATTRIB;
+
+ if (inotify_add_watch(s->inotify_fd, k, flags) >= 0)
+ exists = true;
+ }
+
+ return 0;
+
+fail:
+ free(k);
+
+ path_unwatch_one(p, s);
+ return r;
+}
+
+static void path_unwatch(Path *p) {
+ PathSpec *s;
+
+ assert(p);
+
+ LIST_FOREACH(spec, s, p->specs)
+ path_unwatch_one(p, s);
+}
+
+static int path_watch(Path *p) {
+ int r;
+ PathSpec *s;
+
+ assert(p);
+
+ LIST_FOREACH(spec, s, p->specs)
+ if ((r = path_watch_one(p, s)) < 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)
+ path_unwatch(p);
+
+ if (state != old_state)
+ log_debug("%s changed %s -> %s",
+ p->meta.id,
+ path_state_to_string(old_state),
+ path_state_to_string(state));
+
+ unit_notify(UNIT(p), state_translation_table[old_state], state_translation_table[state]);
+}
+
+static void path_enter_waiting(Path *p, bool initial);
+
+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);
+ else
+ path_set_state(p, p->deserialized_state);
+ }
+
+ return 0;
+}
+
+static void path_enter_dead(Path *p, bool success) {
+ assert(p);
+
+ if (!success)
+ p->failure = true;
+
+ path_set_state(p, p->failure ? PATH_MAINTAINANCE : PATH_DEAD);
+}
+
+static void path_enter_running(Path *p) {
+ int r;
+ assert(p);
+
+ if ((r = manager_add_job(UNIT(p)->meta.manager, JOB_START, p->unit, JOB_REPLACE, true, NULL)) < 0)
+ goto fail;
+
+ path_set_state(p, PATH_RUNNING);
+ return;
+
+fail:
+ log_warning("%s failed to queue unit startup job: %s", p->meta.id, strerror(-r));
+ path_enter_dead(p, false);
+}
+
+
+static void path_enter_waiting(Path *p, bool initial) {
+ PathSpec *s;
+ int r;
+ bool good = false;
+
+ LIST_FOREACH(spec, s, p->specs) {
+
+ switch (s->type) {
+
+ case PATH_EXISTS:
+ good = access(s->path, F_OK) >= 0;
+ break;
+
+ case PATH_DIRECTORY_NOT_EMPTY:
+ good = dir_is_empty(s->path) == 0;
+ break;
+
+ case PATH_CHANGED: {
+ bool b;
+
+ b = access(s->path, F_OK) >= 0;
+ good = !initial && b != s->previous_exists;
+ s->previous_exists = b;
+ break;
+ }
+
+ default:
+ ;
+ }
+
+ if (good)
+ break;
+ }
+
+ if (good) {
+ path_enter_running(p);
+ return;
+ }
+
+ if ((r = path_watch(p)) < 0)
+ goto fail;
+
+ path_set_state(p, PATH_WAITING);
+ return;
+
+fail:
+ log_warning("%s failed to enter waiting state: %s", p->meta.id, strerror(-r));
+ path_enter_dead(p, false);
+}
+
+static int path_start(Unit *u) {
+ Path *p = PATH(u);
+
+ assert(p);
+ assert(p->state == PATH_DEAD || p->state == PATH_MAINTAINANCE);
+
+ if (p->unit->meta.load_state != UNIT_LOADED)
+ return -ENOENT;
+
+ p->failure = false;
+path_enter_waiting(p, true);
+ return 0;
+}
+
+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, true);
+ return 0;
+}
+
+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));
+
+ 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;
+
+ if ((state = path_state_from_string(value)) < 0)
+ log_debug("Failed to parse state value %s", value);
+ else
+ p->deserialized_state = state;
+ } else
+ log_debug("Unknown serialization key '%s'", key);
+
+ return 0;
+}
+
+static UnitActiveState path_active_state(Unit *u) {
+ assert(u);
+
+ return state_translation_table[PATH(u)->state];
+}
+
+static const char *path_sub_state_to_string(Unit *u) {
+ assert(u);
+
+ return path_state_to_string(PATH(u)->state);
+}
+
+static void path_fd_event(Unit *u, int fd, uint32_t events, Watch *w) {
+ Path *p = PATH(u);
+ int l;
+ ssize_t k;
+ struct inotify_event *buf = NULL;
+ PathSpec *s;
+
+ assert(p);
+ assert(fd >= 0);
+
+ if (p->state != PATH_WAITING)
+ return;
+
+ log_debug("inotify wakeup on %s.", u->meta.id);
+
+ if (events != EPOLLIN) {
+ log_error("Got Invalid poll event on inotify.");
+ goto fail;
+ }
+
+ LIST_FOREACH(spec, s, p->specs)
+ if (s->inotify_fd == fd)
+ break;
+
+ if (!s) {
+ log_error("Got event on unknown fd.");
+ goto fail;
+ }
+
+ if (ioctl(fd, FIONREAD, &l) < 0) {
+ log_error("FIONREAD failed: %s", strerror(errno));
+ goto fail;
+ }
+
+ if (!(buf = malloc(l))) {
+ log_error("Failed to allocate buffer: %s", strerror(-ENOMEM));
+ goto fail;
+ }
+
+ if ((k = read(fd, buf, l)) < 0) {
+ log_error("Failed to read inotify event: %s", strerror(-errno));
+ goto fail;
+ }
+
+ if ((size_t) k < sizeof(struct inotify_event) ||
+ (size_t) k < sizeof(struct inotify_event) + buf->len) {
+ log_error("inotify event too small.");
+ goto fail;
+ }
+
+ if (s->type == PATH_CHANGED && s->primary_wd == buf->wd)
+ path_enter_running(p);
+ else
+ path_enter_waiting(p, false);
+
+ free(buf);
+
+ return;
+
+fail:
+ free(buf);
+ path_enter_dead(p, false);
+}
+
+void path_unit_notify(Unit *u, UnitActiveState new_state) {
+ char *n;
+ int r;
+ Iterator i;
+
+ if (u->meta.type == UNIT_PATH)
+ return;
+
+ SET_FOREACH(n, u->meta.names, i) {
+ char *k;
+ Unit *t;
+ Path *p;
+
+ if (!(k = unit_name_change_suffix(n, ".path"))) {
+ r = -ENOMEM;
+ goto fail;
+ }
+
+ t = manager_get_unit(u->meta.manager, k);
+ free(k);
+
+ if (!t)
+ continue;
+
+ if (t->meta.load_state != UNIT_LOADED)
+ continue;
+
+ p = PATH(t);
+
+ if (p->unit != u)
+ continue;
+
+ if (p->state == PATH_RUNNING && new_state == UNIT_INACTIVE) {
+ log_debug("%s got notified about unit deactivation.", p->meta.id);
+ path_enter_waiting(p, false);
+ }
+ }
+
+ return;
+
+fail:
+ log_error("Failed find path unit: %s", strerror(-r));
+}
+
+static const char* const path_state_table[_PATH_STATE_MAX] = {
+ [PATH_DEAD] = "dead",
+ [PATH_WAITING] = "waiting",
+ [PATH_RUNNING] = "running",
+ [PATH_MAINTAINANCE] = "maintainance"
+};
+
+DEFINE_STRING_TABLE_LOOKUP(path_state, PathState);
+
+static const char* const path_type_table[_PATH_TYPE_MAX] = {
+ [PATH_EXISTS] = "PathExists",
+ [PATH_CHANGED] = "PathChanged",
+ [PATH_DIRECTORY_NOT_EMPTY] = "DirectoryNotEmpty"
+};
+
+DEFINE_STRING_TABLE_LOOKUP(path_type, PathType);
+
+const UnitVTable path_vtable = {
+ .suffix = ".path",
+
+ .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,
+
+ .fd_event = path_fd_event,
+
+ .bus_message_handler = bus_path_message_handler
+};