This patch ensures that session devices are saved for each session.
In order to make the revokation logic work when logind is restarted, the
session devices are now saved in the session state files and their respective
file descriptors sent to PID1's fdstore in order to keep them open accross
restart.
This is mandatory in order to keep the revokation logic working. Indeed in case
of input-devices, the same file descriptors must be shared by logind and a
given session controller in order EVIOCREVOKE to work otherwise multiple
sessions can have device access in parallel.
This should be the only remaining and missing piece for making logind fully
restartable.
Fixes: #1163
if (uid != 0 && (force || uid != s->user->uid))
return sd_bus_error_setf(error, SD_BUS_ERROR_ACCESS_DENIED, "Only owner of session may take control");
- r = session_set_controller(s, sd_bus_message_get_sender(message), force);
+ r = session_set_controller(s, sd_bus_message_get_sender(message), force, true);
if (r < 0)
return r;
* equivalent). */
return sd_bus_error_setf(error, BUS_ERROR_DEVICE_IS_TAKEN, "Device already taken");
- r = session_device_new(s, dev, &sd);
+ r = session_device_new(s, dev, true, &sd);
if (r < 0)
return r;
+ r = session_device_save(sd);
+ if (r < 0)
+ goto error;
+
r = sd_bus_reply_method_return(message, "hb", sd->fd, !sd->active);
if (r < 0)
- session_device_free(sd);
+ goto error;
+
+ session_save(s);
+ return 0;
+error:
+ session_device_free(sd);
return r;
}
return sd_bus_error_setf(error, BUS_ERROR_DEVICE_NOT_TAKEN, "Device not taken");
session_device_free(sd);
+ session_save(s);
+
return sd_bus_reply_method_return(message, NULL);
}
r = session_device_open(sd, true);
if (r < 0)
return r;
- close_nointr(sd->fd);
+ /* For evdev devices, the file descriptor might be left
+ * uninitialized. This might happen while resuming into a
+ * session and logind has been restarted right before. */
+ safe_close(sd->fd);
sd->fd = r;
break;
case DEVICE_TYPE_UNKNOWN:
return r;
}
-int session_device_new(Session *s, dev_t dev, SessionDevice **out) {
+int session_device_new(Session *s, dev_t dev, bool open_device, SessionDevice **out) {
SessionDevice *sd;
int r;
goto error;
}
- /* Open the device for the first time. We need a valid fd to pass back
- * to the caller. If the session is not active, this _might_ immediately
- * revoke access and thus invalidate the fd. But this is still needed
- * to pass a valid fd back. */
- sd->active = session_is_active(s);
- r = session_device_open(sd, sd->active);
- if (r < 0) {
- /* EINVAL _may_ mean a master is active; retry inactive */
- if (sd->active && r == -EINVAL) {
- sd->active = false;
- r = session_device_open(sd, false);
+ if (open_device) {
+ /* Open the device for the first time. We need a valid fd to pass back
+ * to the caller. If the session is not active, this _might_ immediately
+ * revoke access and thus invalidate the fd. But this is still needed
+ * to pass a valid fd back. */
+ sd->active = session_is_active(s);
+ r = session_device_open(sd, sd->active);
+ if (r < 0) {
+ /* EINVAL _may_ mean a master is active; retry inactive */
+ if (sd->active && r == -EINVAL) {
+ sd->active = false;
+ r = session_device_open(sd, false);
+ }
+ if (r < 0)
+ goto error;
}
- if (r < 0)
- goto error;
+ sd->fd = r;
}
- sd->fd = r;
LIST_PREPEND(sd_by_device, sd->device->session_devices, sd);
void session_device_resume_all(Session *s) {
SessionDevice *sd;
Iterator i;
- int r;
assert(s);
HASHMAP_FOREACH(sd, s->devices, i) {
if (!sd->active) {
- r = session_device_start(sd);
- if (!r)
- session_device_notify(sd, SESSION_DEVICE_RESUME);
+ if (session_device_start(sd) < 0)
+ continue;
+ if (session_device_save(sd) < 0)
+ continue;
+ session_device_notify(sd, SESSION_DEVICE_RESUME);
}
}
}
return num_pending;
}
+
+int session_device_save(SessionDevice *sd) {
+ _cleanup_free_ char *state = NULL;
+ int r;
+
+ assert(sd);
+
+ /* Store device fd in PID1. It will send it back to us on
+ * restart so revocation will continue to work. To make things
+ * simple, send fds for all type of devices even if they don't
+ * support the revocation mechanism so we don't have to handle
+ * them differently later.
+ *
+ * Note: for device supporting revocation, PID1 will drop a
+ * stored fd automatically if the corresponding device is
+ * revoked. */
+ r = asprintf(&state, "FDSTORE=1\n"
+ "FDNAME=session-%s", sd->session->id);
+ if (r < 0)
+ return -ENOMEM;
+
+ return sd_pid_notify_with_fds(0, false, state, &sd->fd, 1);
+}
+
+void session_device_attach_fd(SessionDevice *sd, int fd, bool active) {
+ assert(fd > 0);
+ assert(sd);
+ assert(sd->fd < 0);
+ assert(!sd->active);
+
+ sd->fd = fd;
+ sd->active = active;
+}
LIST_FIELDS(struct SessionDevice, sd_by_device);
};
-int session_device_new(Session *s, dev_t dev, SessionDevice **out);
+int session_device_new(Session *s, dev_t dev, bool open_device, SessionDevice **out);
void session_device_free(SessionDevice *sd);
void session_device_complete_pause(SessionDevice *sd);
void session_device_resume_all(Session *s);
void session_device_pause_all(Session *s);
unsigned int session_device_try_pause_all(Session *s);
+
+int session_device_save(SessionDevice *sd);
+void session_device_attach_fd(SessionDevice *sd, int fd, bool active);
LIST_PREPEND(sessions_by_user, u->sessions, s);
}
+static void session_save_devices(Session *s, FILE *f) {
+ SessionDevice *sd;
+ Iterator i;
+
+ if (!hashmap_isempty(s->devices)) {
+ fprintf(f, "DEVICES=");
+ HASHMAP_FOREACH(sd, s->devices, i)
+ fprintf(f, "%u:%u ", major(sd->dev), minor(sd->dev));
+ fprintf(f, "\n");
+ }
+}
+
int session_save(Session *s) {
_cleanup_free_ char *temp_path = NULL;
_cleanup_fclose_ FILE *f = NULL;
s->timestamp.realtime,
s->timestamp.monotonic);
- if (s->controller)
+ if (s->controller) {
fprintf(f, "CONTROLLER=%s\n", s->controller);
+ session_save_devices(s, f);
+ }
r = fflush_and_check(f);
if (r < 0)
return log_error_errno(r, "Failed to save session data %s: %m", s->state_file);
}
+static int session_load_devices(Session *s, const char *devices) {
+ const char *p;
+ int r = 0;
+
+ assert(s);
+
+ for (p = devices;;) {
+ _cleanup_free_ char *word = NULL;
+ SessionDevice *sd;
+ dev_t dev;
+ int k;
+
+ k = extract_first_word(&p, &word, NULL, 0);
+ if (k == 0)
+ break;
+ if (k < 0) {
+ r = k;
+ break;
+ }
+
+ k = parse_dev(word, &dev);
+ if (k < 0) {
+ r = k;
+ continue;
+ }
+
+ /* The file descriptors for loaded devices will be reattached later. */
+ k = session_device_new(s, dev, false, &sd);
+ if (k < 0)
+ r = k;
+ }
+
+ if (r < 0)
+ log_error_errno(r, "Loading session devices for session %s failed: %m", s->id);
+
+ return r;
+}
int session_load(Session *s) {
_cleanup_free_ char *remote = NULL,
*uid = NULL,
*realtime = NULL,
*monotonic = NULL,
- *controller = NULL;
+ *controller = NULL,
+ *active = NULL,
+ *devices = NULL;
int k, r;
"REALTIME", &realtime,
"MONOTONIC", &monotonic,
"CONTROLLER", &controller,
+ "ACTIVE", &active,
+ "DEVICES", &devices,
NULL);
if (r < 0)
if (monotonic)
timestamp_deserialize(monotonic, &s->timestamp.monotonic);
+ if (active) {
+ k = parse_boolean(active);
+ if (k >= 0)
+ s->was_active = k;
+ }
+
if (controller) {
- if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0)
- session_set_controller(s, controller, false);
- else
+ if (bus_name_has_owner(s->manager->bus, controller, NULL) > 0) {
+ session_set_controller(s, controller, false, false);
+ session_load_devices(s, devices);
+ } else
session_restore_vt(s);
}
return 0;
}
-int session_set_controller(Session *s, const char *sender, bool force) {
+int session_set_controller(Session *s, const char *sender, bool force, bool prepare) {
_cleanup_free_ char *name = NULL;
int r;
* Note that we reset the VT on ReleaseControl() and if the controller
* exits.
* If logind crashes/restarts, we restore the controller during restart
- * or reset the VT in case it crashed/exited, too. */
- r = session_prepare_vt(s);
- if (r < 0) {
- s->track = sd_bus_track_unref(s->track);
- return r;
+ * (without preparing the VT since the controller has probably overridden
+ * VT state by now) or reset the VT in case it crashed/exited, too. */
+ if (prepare) {
+ r = session_prepare_vt(s);
+ if (r < 0) {
+ s->track = sd_bus_track_unref(s->track);
+ return r;
+ }
}
session_release_controller(s, true);
bool started:1;
bool stopping:1;
+ bool was_active:1;
+
sd_bus_message *create_message;
sd_event_source *timer_event_source;
void session_leave_vt(Session *s);
bool session_is_controller(Session *s, const char *sender);
-int session_set_controller(Session *s, const char *sender, bool force);
+int session_set_controller(Session *s, const char *sender, bool force, bool prepare);
void session_drop_controller(Session *s);
int bus_session_method_activate(sd_bus_message *message, void *userdata, sd_bus_error *error);
return r;
}
+static int manager_attach_fds(Manager *m) {
+ _cleanup_strv_free_ char **fdnames = NULL;
+ int n, i, fd;
+
+ /* Upon restart, PID1 will send us back all fds of session devices
+ * that we previously opened. Each file descriptor is associated
+ * with a given session. The session ids are passed through FDNAMES. */
+
+ n = sd_listen_fds_with_names(true, &fdnames);
+ if (n <= 0)
+ return n;
+
+ for (i = 0; i < n; i++) {
+ struct stat st;
+ SessionDevice *sd;
+ Session *s;
+ char *id;
+
+ fd = SD_LISTEN_FDS_START + i;
+
+ id = startswith(fdnames[i], "session-");
+ if (!id)
+ continue;
+
+ s = hashmap_get(m->sessions, id);
+ if (!s) {
+ /* If the session doesn't exist anymore, the associated session
+ * device attached to this fd doesn't either. Let's simply close
+ * this fd. */
+ log_debug("Failed to attach fd for unknown session: %s", id);
+ close_nointr(fd);
+ continue;
+ }
+
+ if (fstat(fd, &st) < 0) {
+ /* The device is allowed to go away at a random point, in which
+ * case fstat failing is expected. */
+ log_debug_errno(errno, "Failed to stat device fd for session %s: %m", id);
+ close_nointr(fd);
+ continue;
+ }
+
+ sd = hashmap_get(s->devices, &st.st_rdev);
+ if (!sd) {
+ /* Weird we got an fd for a session device which wasn't
+ * recorded in the session state file... */
+ log_warning("Got fd for missing session device [%u:%u] in session %s",
+ major(st.st_rdev), minor(st.st_rdev), s->id);
+ close_nointr(fd);
+ continue;
+ }
+
+ log_debug("Attaching fd to session device [%u:%u] for session %s",
+ major(st.st_rdev), minor(st.st_rdev), s->id);
+
+ session_device_attach_fd(sd, fd, s->was_active);
+ }
+
+ return 0;
+}
+
static int manager_enumerate_sessions(Manager *m) {
_cleanup_closedir_ DIR *d = NULL;
struct dirent *de;
- int r = 0;
+ int r = 0, k;
assert(m);
FOREACH_DIRENT(de, d, return -errno) {
struct Session *s;
- int k;
if (!dirent_is_file(de))
continue;
k = manager_add_session(m, de->d_name, &s);
if (k < 0) {
log_error_errno(k, "Failed to add session by file name %s: %m", de->d_name);
-
r = k;
continue;
}
r = k;
}
+ /* We might be restarted and PID1 could have sent us back the
+ * session device fds we previously saved. */
+ k = manager_attach_fds(m);
+ if (k < 0)
+ log_warning_errno(k, "Failed to reattach session device fds: %m");
+
return r;
}
assert(m);
return config_parse_many_nulstr(PKGSYSCONFDIR "/logind.conf",
- CONF_PATHS_NULSTR("systemd/logind.conf.d"),
- "Login\0",
- config_item_perf_lookup, logind_gperf_lookup,
- false, m);
+ CONF_PATHS_NULSTR("systemd/logind.conf.d"),
+ "Login\0",
+ config_item_perf_lookup, logind_gperf_lookup,
+ false, m);
#else
const char* logind_conf = getenv("ELOGIND_CONF_FILE");
~ianmdlvl / elogind.git / commitdiff