diff options
Diffstat (limited to 'src/path.c')
| -rw-r--r-- | src/path.c | 770 |
1 files changed, 770 insertions, 0 deletions
diff --git a/src/path.c b/src/path.c new file mode 100644 index 0000000000..e97cd09810 --- /dev/null +++ b/src/path.c @@ -0,0 +1,770 @@ +/*-*- 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 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" +#include "special.h" +#include "bus-errors.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 +}; + +int path_spec_watch(PathSpec *s, Unit *u) { + + 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 *k, *slash; + int r; + + assert(u); + assert(s); + + path_spec_unwatch(s, u); + + 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(u, 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; + + do { + int flags; + + /* This assumes the path was passed through path_kill_slashes()! */ + if (!(slash = strrchr(k, '/'))) + break; + + /* Trim the path at the last slash. Keep the slash if it's the root dir. */ + slash[slash == k] = 0; + + flags = IN_MOVE_SELF; + if (!exists) + flags |= IN_DELETE_SELF | IN_ATTRIB | IN_CREATE | IN_MOVED_TO; + + if (inotify_add_watch(s->inotify_fd, k, flags) >= 0) + exists = true; + } while (slash != k); + + return 0; + +fail: + free(k); + + path_spec_unwatch(s, u); + return r; +} + +void path_spec_unwatch(PathSpec *s, Unit *u) { + + if (s->inotify_fd < 0) + return; + + unit_unwatch_fd(u, &s->watch); + + close_nointr_nofail(s->inotify_fd); + s->inotify_fd = -1; +} + +int path_spec_fd_event(PathSpec *s, uint32_t events) { + uint8_t *buf = NULL; + struct inotify_event *e; + ssize_t k; + int l; + int r = 0; + + if (events != EPOLLIN) { + log_error("Got Invalid poll event on inotify."); + r = -EINVAL; + goto out; + } + + if (ioctl(s->inotify_fd, FIONREAD, &l) < 0) { + log_error("FIONREAD failed: %m"); + r = -errno; + goto out; + } + + assert(l > 0); + + if (!(buf = malloc(l))) { + log_error("Failed to allocate buffer: %m"); + r = -errno; + goto out; + } + + if ((k = read(s->inotify_fd, buf, l)) < 0) { + log_error("Failed to read inotify event: %m"); + r = -errno; + goto out; + } + + e = (struct inotify_event*) buf; + + while (k > 0) { + size_t step; + + if ((s->type == PATH_CHANGED || s->type == PATH_MODIFIED) && + s->primary_wd == e->wd) + r = 1; + + step = sizeof(struct inotify_event) + e->len; + assert(step <= (size_t) k); + + e = (struct inotify_event*) ((uint8_t*) e + step); + k -= step; + } +out: + free(buf); + 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 bool path_spec_startswith(PathSpec *s, const char *what) { + return path_startswith(s->path, what); +} + +static void path_spec_mkdir(PathSpec *s, mode_t mode) { + int r; + + if (s->type == PATH_EXISTS || s->type == PATH_EXISTS_GLOB) + return; + + if ((r = mkdir_p(s->path, mode)) < 0) + log_warning("mkdir(%s) failed: %s", s->path, strerror(-r)); +} + +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; +} + +static void path_done(Unit *u) { + Path *p = PATH(u); + PathSpec *s; + + assert(p); + + unit_ref_unset(&p->unit); + + while ((s = p->specs)) { + path_spec_unwatch(s, u); + LIST_REMOVE(PathSpec, spec, p->specs, s); + path_spec_done(s); + free(s); + } +} + +int path_add_one_mount_link(Path *p, Mount *m) { + PathSpec *s; + int r; + + assert(p); + assert(m); + + if (UNIT(p)->load_state != UNIT_LOADED || + UNIT(m)->load_state != UNIT_LOADED) + return 0; + + LIST_FOREACH(spec, s, p->specs) { + + if (!path_spec_startswith(s, m->where)) + continue; + + if ((r = unit_add_two_dependencies(UNIT(p), UNIT_AFTER, UNIT_REQUIRES, UNIT(m), true)) < 0) + return r; + } + + return 0; +} + +static int path_add_mount_links(Path *p) { + Unit *other; + int r; + + assert(p); + + LIST_FOREACH(units_by_type, other, UNIT(p)->manager->units_by_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)->load_state != UNIT_LOADED) + return 0; + + if (!p->specs) { + log_error("%s lacks path setting. Refusing.", UNIT(p)->id); + return -EINVAL; + } + + return 0; +} + +static int path_add_default_dependencies(Path *p) { + int r; + + assert(p); + + if (UNIT(p)->manager->running_as == MANAGER_SYSTEM) { + if ((r = unit_add_dependency_by_name(UNIT(p), UNIT_BEFORE, SPECIAL_BASIC_TARGET, NULL, true)) < 0) + return r; + + if ((r = unit_add_two_dependencies_by_name(UNIT(p), UNIT_AFTER, UNIT_REQUIRES, SPECIAL_SYSINIT_TARGET, NULL, true)) < 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); + + if ((r = unit_load_fragment_and_dropin(u)) < 0) + return r; + + if (u->load_state == UNIT_LOADED) { + + if (!UNIT_DEREF(p->unit)) { + Unit *x; + + r = unit_load_related_unit(u, ".service", &x); + if (r < 0) + return r; + + unit_ref_set(&p->unit, x); + } + + r = unit_add_two_dependencies(u, UNIT_BEFORE, UNIT_TRIGGERS, UNIT_DEREF(p->unit), true); + if (r < 0) + return r; + + if ((r = path_add_mount_links(p)) < 0) + return r; + + if (UNIT(p)->default_dependencies) + if ((r = path_add_default_dependencies(p)) < 0) + return r; + } + + return path_verify(p); +} + +static void path_dump(Unit *u, FILE *f, const char *prefix) { + Path *p = PATH(u); + PathSpec *s; + + assert(p); + assert(f); + + 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, UNIT_DEREF(p->unit)->id, + 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, UNIT(p)); +} + +static int path_watch(Path *p) { + int r; + PathSpec *s; + + assert(p); + + LIST_FOREACH(spec, s, p->specs) + if ((r = path_spec_watch(s, UNIT(p))) < 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("%s changed %s -> %s", + UNIT(p)->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], 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) { + int r; + DBusError error; + + assert(p); + dbus_error_init(&error); + + /* Don't start job if we are supposed to go down */ + if (UNIT(p)->job && UNIT(p)->job->type == JOB_STOP) + return; + + if ((r = manager_add_job(UNIT(p)->manager, JOB_START, UNIT_DEREF(p->unit), JOB_REPLACE, true, &error, NULL)) < 0) + goto fail; + + p->inotify_triggered = false; + + if ((r = path_watch(p)) < 0) + goto fail; + + path_set_state(p, PATH_RUNNING); + return; + +fail: + log_warning("%s failed to queue unit startup job: %s", UNIT(p)->id, bus_error(&error, r)); + path_enter_dead(p, PATH_FAILURE_RESOURCES); + + dbus_error_free(&error); +} + +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_debug("%s got triggered.", UNIT(p)->id); + path_enter_running(p); + return; + } + + if ((r = path_watch(p)) < 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_debug("%s got triggered.", UNIT(p)->id); + path_enter_running(p); + return; + } + + path_set_state(p, PATH_WAITING); + return; + +fail: + log_warning("%s failed to enter waiting state: %s", UNIT(p)->id, strerror(-r)); + 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_DEREF(p->unit)->load_state != UNIT_LOADED) + return -ENOENT; + + path_mkdir(p); + + p->result = PATH_SUCCESS; + path_enter_waiting(p, true, 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, PATH_SUCCESS); + 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)); + 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; + + if ((state = path_state_from_string(value)) < 0) + log_debug("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_debug("Failed to parse result value %s", value); + else if (f != PATH_SUCCESS) + p->result = f; + + } 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); + PathSpec *s; + int changed; + + assert(p); + assert(fd >= 0); + + if (p->state != PATH_WAITING && + p->state != PATH_RUNNING) + return; + + /* 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, events); + 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; + +fail: + path_enter_dead(p, PATH_FAILURE_RESOURCES); +} + +void path_unit_notify(Unit *u, UnitActiveState new_state) { + Iterator i; + Unit *k; + + if (u->type == UNIT_PATH) + return; + + SET_FOREACH(k, u->dependencies[UNIT_TRIGGERED_BY], i) { + Path *p; + + if (k->type != UNIT_PATH) + continue; + + if (k->load_state != UNIT_LOADED) + continue; + + p = PATH(k); + + if (p->state == PATH_RUNNING && new_state == UNIT_INACTIVE) { + log_debug("%s got notified about unit deactivation.", UNIT(p)->id); + + /* 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_CHANGED] = "PathChanged", + [PATH_MODIFIED] = "PathModified", + [PATH_DIRECTORY_NOT_EMPTY] = "DirectoryNotEmpty" +}; + +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 = { + .suffix = ".path", + .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, + + .fd_event = path_fd_event, + + .reset_failed = path_reset_failed, + + .bus_interface = "org.freedesktop.systemd1.Path", + .bus_message_handler = bus_path_message_handler, + .bus_invalidating_properties = bus_path_invalidating_properties +}; 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