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Systemd/src/path.c

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/*-*- 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_MAINTENANCE] = UNIT_MAINTENANCE
};
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_two_dependencies(UNIT(p), UNIT_AFTER, 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 (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_add_default_dependencies(Path *p) {
int r;
assert(p);
if (p->meta.manager->running_as == MANAGER_SYSTEM)
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_CONFLICTED_BY, SPECIAL_SHUTDOWN_TARGET, NULL, true);
}
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;
if (p->meta.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"
"%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);
}
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_MAINTENANCE : 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 (p->meta.job && p->meta.job->type == JOB_STOP)
return;
if ((r = manager_add_job(p->meta.manager, JOB_START, p->unit, JOB_REPLACE, true, &error, 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, bus_error(&error, r));
path_enter_dead(p, false);
dbus_error_free(&error);
}
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_MAINTENANCE);
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 void path_reset_maintenance(Unit *u) {
Path *p = PATH(u);
assert(p);
if (p->state == PATH_MAINTENANCE)
path_set_state(p, PATH_DEAD);
p->failure = false;
}
static const char* const path_state_table[_PATH_STATE_MAX] = {
[PATH_DEAD] = "dead",
[PATH_WAITING] = "waiting",
[PATH_RUNNING] = "running",
[PATH_MAINTENANCE] = "maintenance"
};
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,
.reset_maintenance = path_reset_maintenance,
.bus_interface = "org.freedesktop.systemd1.Path",
.bus_message_handler = bus_path_message_handler
};
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