#include <inttypes.h>
#include <urcu/list.h>
#include <urcu/uatomic.h>
+#include <sys/stat.h>
#include <common/defaults.h>
#include <common/common.h>
#include <lttng/channel.h>
#include <lttng/channel-internal.h>
#include <lttng/rotate-internal.h>
+#include <lttng/location-internal.h>
#include <common/string-utils/string-utils.h>
#include "channel.h"
#include "cmd.h"
+/* Sleep for 100ms between each check for the shm path's deletion. */
+#define SESSION_DESTROY_SHM_PATH_CHECK_DELAY_US 100000
+
+static enum lttng_error_code wait_on_path(void *path);
+
+/*
+ * Command completion handler that is used by the destroy command
+ * when a session that has a non-default shm_path is being destroyed.
+ *
+ * See comment in cmd_destroy_session() for the rationale.
+ */
+static struct destroy_completion_handler {
+ struct cmd_completion_handler handler;
+ char shm_path[member_sizeof(struct ltt_session, shm_path)];
+} destroy_completion_handler = {
+ .handler = {
+ .run = wait_on_path,
+ .data = destroy_completion_handler.shm_path
+ },
+ .shm_path = { 0 },
+};
+
+static struct cmd_completion_handler *current_completion_handler;
+
/*
* Used to keep a unique index for each relayd socket created where this value
* is associated with streams on the consumer so it can match the right relayd
PERROR("write kernel poll pipe");
}
+ if (session->shm_path[0]) {
+ /*
+ * When a session is created with an explicit shm_path,
+ * the consumer daemon will create its shared memory files
+ * at that location and will *not* unlink them. This is normal
+ * as the intention of that feature is to make it possible
+ * to retrieve the content of those files should a crash occur.
+ *
+ * To ensure the content of those files can be used, the
+ * sessiond daemon will replicate the content of the metadata
+ * cache in a metadata file.
+ *
+ * On clean-up, it is expected that the consumer daemon will
+ * unlink the shared memory files and that the session daemon
+ * will unlink the metadata file. Then, the session's directory
+ * in the shm path can be removed.
+ *
+ * Unfortunately, a flaw in the design of the sessiond's and
+ * consumerd's tear down of channels makes it impossible to
+ * determine when the sessiond _and_ the consumerd have both
+ * destroyed their representation of a channel. For one, the
+ * unlinking, close, and rmdir happen in deferred 'call_rcu'
+ * callbacks in both daemons.
+ *
+ * However, it is also impossible for the sessiond to know when
+ * the consumer daemon is done destroying its channel(s) since
+ * it occurs as a reaction to the closing of the channel's file
+ * descriptor. There is no resulting communication initiated
+ * from the consumerd to the sessiond to confirm that the
+ * operation is completed (and was successful).
+ *
+ * Until this is all fixed, the session daemon checks for the
+ * removal of the session's shm path which makes it possible
+ * to safely advertise a session as having been destroyed.
+ *
+ * Prior to this fix, it was not possible to reliably save
+ * a session making use of the --shm-path option, destroy it,
+ * and load it again. This is because the creation of the
+ * session would fail upon seeing the session's shm path
+ * already in existence.
+ *
+ * Note that none of the error paths in the check for the
+ * directory's existence return an error. This is normal
+ * as there isn't much that can be done. The session will
+ * be destroyed properly, except that we can't offer the
+ * guarantee that the same session can be re-created.
+ */
+ current_completion_handler = &destroy_completion_handler.handler;
+ ret = lttng_strncpy(destroy_completion_handler.shm_path,
+ session->shm_path,
+ sizeof(destroy_completion_handler.shm_path));
+ assert(!ret);
+ }
ret = session_destroy(session);
return ret;
session->current_archive_id++;
session->rotate_pending = true;
session->rotation_state = LTTNG_ROTATION_STATE_ONGOING;
+ ret = notification_thread_command_session_rotation_ongoing(
+ notification_thread_handle,
+ session->name, session->uid, session->gid,
+ session->current_archive_id);
+ if (ret != LTTNG_OK) {
+ ERR("Failed to notify notification thread that a session rotation is ongoing for session %s",
+ session->name);
+ }
/*
* Create the path name for the next chunk.
* session_list locks.
*/
if (!session->kernel_session && !ust_active) {
+ struct lttng_trace_archive_location *location;
+
+ session->rotate_pending = false;
+ session->rotation_state = LTTNG_ROTATION_STATE_COMPLETED;
ret = rename_complete_chunk(session, now);
if (ret < 0) {
ERR("Failed to rename completed rotation chunk");
goto end;
}
- session->rotate_pending = false;
- session->rotation_state = LTTNG_ROTATION_STATE_COMPLETED;
+
+ /* Ownership of location is transferred. */
+ location = session_get_trace_archive_location(session);
+ ret = notification_thread_command_session_rotation_completed(
+ notification_thread_handle,
+ session->name,
+ session->uid,
+ session->gid,
+ session->current_archive_id,
+ location);
+ if (ret != LTTNG_OK) {
+ ERR("Failed to notify notification thread that rotation is complete for session %s",
+ session->name);
+ }
}
}
* Command LTTNG_ROTATION_SET_SCHEDULE from the lttng-ctl library.
*
* Configure the automatic rotation parameters.
- * Set to -1ULL to disable them.
+ * 'activate' to true means activate the rotation schedule type with 'new_value'.
+ * 'activate' to false means deactivate the rotation schedule and validate that
+ * 'new_value' has the same value as the currently active value.
*
- * Return 0 on success or else an LTTNG_ERR code.
+ * Return 0 on success or else a positive LTTNG_ERR code.
*/
int cmd_rotation_set_schedule(struct ltt_session *session,
- uint64_t timer_us, uint64_t size,
+ bool activate, enum lttng_rotation_schedule_type schedule_type,
+ uint64_t new_value,
struct notification_thread_handle *notification_thread_handle)
{
int ret;
+ uint64_t *parameter_value;
assert(session);
if (session->live_timer || session->snapshot_mode ||
!session->output_traces) {
+ DBG("Failing ROTATION_SET_SCHEDULE command as the rotation feature is not available for this session");
ret = LTTNG_ERR_ROTATION_NOT_AVAILABLE;
goto end;
}
- /* Trying to override an already active timer. */
- if (timer_us && timer_us != -1ULL && session->rotate_timer_period) {
- ret = LTTNG_ERR_ROTATION_TIMER_SET;
+ switch (schedule_type) {
+ case LTTNG_ROTATION_SCHEDULE_TYPE_SIZE_THRESHOLD:
+ parameter_value = &session->rotate_size;
+ break;
+ case LTTNG_ROTATION_SCHEDULE_TYPE_PERIODIC:
+ parameter_value = &session->rotate_timer_period;
+ if (new_value >= UINT_MAX) {
+ DBG("Failing ROTATION_SET_SCHEDULE command as the value requested for a periodic rotation schedule is invalid: %" PRIu64 " > %u (UINT_MAX)",
+ new_value, UINT_MAX);
+ ret = LTTNG_ERR_INVALID;
+ goto end;
+ }
+ break;
+ default:
+ WARN("Failing ROTATION_SET_SCHEDULE command on unknown schedule type");
+ ret = LTTNG_ERR_INVALID;
goto end;
- /* Trying to disable an inactive timer. */
- } else if (timer_us == -1ULL && !session->rotate_timer_period) {
- ret = LTTNG_ERR_ROTATION_NO_TIMER_SET;
+ }
+
+ /* Improper use of the API. */
+ if (new_value == -1ULL) {
+ WARN("Failing ROTATION_SET_SCHEDULE command as the value requested is -1");
+ ret = LTTNG_ERR_INVALID;
goto end;
}
- if (size && size != -1ULL && session->rotate_size) {
- ret = LTTNG_ERR_ROTATION_SIZE_SET;
+ /*
+ * As indicated in struct ltt_session's comments, a value of == 0 means
+ * this schedule rotation type is not in use.
+ *
+ * Reject the command if we were asked to activate a schedule that was
+ * already active.
+ */
+ if (activate && *parameter_value != 0) {
+ DBG("Failing ROTATION_SET_SCHEDULE (activate) command as the schedule is already active");
+ ret = LTTNG_ERR_ROTATION_SCHEDULE_SET;
goto end;
- } else if (size == -1ULL && !session->rotate_size) {
- ret = LTTNG_ERR_ROTATION_NO_SIZE_SET;
+ }
+
+ /*
+ * Reject the command if we were asked to deactivate a schedule that was
+ * not active.
+ */
+ if (!activate && *parameter_value == 0) {
+ DBG("Failing ROTATION_SET_SCHEDULE (deactivate) command as the schedule is already inactive");
+ ret = LTTNG_ERR_ROTATION_SCHEDULE_NOT_SET;
goto end;
}
- if (timer_us && !session->rotate_timer_period) {
- if (timer_us > UINT_MAX) {
- ret = LTTNG_ERR_INVALID;
- goto end;
- }
+ /*
+ * Reject the command if we were asked to deactivate a schedule that
+ * doesn't exist.
+ */
+ if (!activate && *parameter_value != new_value) {
+ DBG("Failing ROTATION_SET_SCHEDULE (deactivate) command as an inexistant schedule was provided");
+ ret = LTTNG_ERR_ROTATION_SCHEDULE_NOT_SET;
+ goto end;
+ }
- session->rotate_timer_period = timer_us;
- /*
- * Only start the timer if the session is active, otherwise
- * it will be started when the session starts.
- */
- if (session->active) {
- ret = sessiond_rotate_timer_start(session, timer_us);
+ *parameter_value = activate ? new_value : 0;
+
+ switch (schedule_type) {
+ case LTTNG_ROTATION_SCHEDULE_TYPE_PERIODIC:
+ if (activate && session->active) {
+ /*
+ * Only start the timer if the session is active,
+ * otherwise it will be started when the session starts.
+ */
+ ret = sessiond_rotate_timer_start(session, new_value);
if (ret) {
- ERR("Failed to enable rotate timer");
+ ERR("Failed to enable session rotation timer in ROTATION_SET_SCHEDULE command");
+ ret = LTTNG_ERR_UNK;
+ goto end;
+ }
+ } else {
+ ret = sessiond_rotate_timer_stop(session);
+ if (ret) {
+ ERR("Failed to disable session rotation timer in ROTATION_SET_SCHEDULE command");
ret = LTTNG_ERR_UNK;
goto end;
}
}
- } else if (timer_us == -1ULL && session->rotate_timer_period > 0) {
- sessiond_rotate_timer_stop(session);
- session->rotate_timer_period = 0;
- }
-
- if (size > 0) {
- if (size == -1ULL) {
- ret = unsubscribe_session_consumed_size_rotation(session,
- notification_thread_handle);
+ break;
+ case LTTNG_ROTATION_SCHEDULE_TYPE_SIZE_THRESHOLD:
+ if (activate) {
+ ret = subscribe_session_consumed_size_rotation(session,
+ new_value, notification_thread_handle);
if (ret) {
+ ERR("Failed to enable consumed-size notification in ROTATION_SET_SCHEDULE command");
ret = LTTNG_ERR_UNK;
goto end;
}
- session->rotate_size = 0;
} else {
- ret = subscribe_session_consumed_size_rotation(session,
- size, notification_thread_handle);
+ ret = unsubscribe_session_consumed_size_rotation(session,
+ notification_thread_handle);
if (ret) {
- PERROR("Subscribe to session usage");
+ ERR("Failed to disable consumed-size notification in ROTATION_SET_SCHEDULE command");
ret = LTTNG_ERR_UNK;
goto end;
}
- session->rotate_size = size;
+
}
+ break;
+ default:
+ /* Would have been caught before. */
+ abort();
}
ret = LTTNG_OK;
return ret;
}
+/* Wait for a given path to be removed before continuing. */
+static enum lttng_error_code wait_on_path(void *path_data)
+{
+ const char *shm_path = path_data;
+
+ DBG("Waiting for the shm path at %s to be removed before completing session destruction",
+ shm_path);
+ while (true) {
+ int ret;
+ struct stat st;
+
+ ret = stat(shm_path, &st);
+ if (ret) {
+ if (errno != ENOENT) {
+ PERROR("stat() returned an error while checking for the existence of the shm path");
+ } else {
+ DBG("shm path no longer exists, completing the destruction of session");
+ }
+ break;
+ } else {
+ if (!S_ISDIR(st.st_mode)) {
+ ERR("The type of shm path %s returned by stat() is not a directory; aborting the wait for shm path removal",
+ shm_path);
+ break;
+ }
+ }
+ usleep(SESSION_DESTROY_SHM_PATH_CHECK_DELAY_US);
+ }
+ return LTTNG_OK;
+}
+
+/*
+ * Returns a pointer to a handler to run on completion of a command.
+ * Returns NULL if no handler has to be run for the last command executed.
+ */
+const struct cmd_completion_handler *cmd_pop_completion_handler(void)
+{
+ struct cmd_completion_handler *handler = current_completion_handler;
+
+ current_completion_handler = NULL;
+ return handler;
+}
+
/*
* Init command subsystem.
*/
projects / lttng-tools.git / blobdiff