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Systemd/src/core/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 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 <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 "mkdir.h"
#include "dbus-path.h"
#include "special.h"
#include "bus-errors.h"
#include "path-util.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;
}
s->primary_wd = inotify_add_watch(s->inotify_fd, k, flags_table[s->type]);
if (s->primary_wd >= 0)
exists = true;
do {
int flags;
/* This assumes the path was passed through path_kill_slashes()! */
slash = strrchr(k, '/');
if (!slash)
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_label(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 == SYSTEMD_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 = {
.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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