diff options
Diffstat (limited to 'src/path.c')
| -rw-r--r-- | src/path.c | 578 |
1 files changed, 578 insertions, 0 deletions
diff --git a/src/path.c b/src/path.c new file mode 100644 index 000000000..b40a8297f --- /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 +}; |