Add create session snapshot API in lttng-sessiond

[lttng-tools.git] / src / bin / lttng-sessiond / cmd.c

diff --git a/src/bin/lttng-sessiond/cmd.c b/src/bin/lttng-sessiond/cmd.c
index 211fc5a34df02b70de775c15880d526d26afe050..60a4ef2fbd95a9a5d5af29e6b509902ca801a29f 100644 (file)
--- a/src/bin/lttng-sessiond/cmd.c
+++ b/src/bin/lttng-sessiond/cmd.c
@@ -25,6 +25,7 @@
 #include <common/common.h>
 #include <common/sessiond-comm/sessiond-comm.h>
 #include <common/relayd/relayd.h>
+#include <common/utils.h>
 
 #include "channel.h"
 #include "consumer.h"
@@ -721,7 +722,7 @@ static int start_kernel_session(struct ltt_kernel_session *ksess, int wpipe)
        struct ltt_kernel_channel *kchan;
 
        /* Open kernel metadata */
-       if (ksess->metadata == NULL) {
+       if (ksess->metadata == NULL && ksess->output_traces) {
                ret = kernel_open_metadata(ksess);
                if (ret < 0) {
                        ret = LTTNG_ERR_KERN_META_FAIL;
@@ -730,7 +731,7 @@ static int start_kernel_session(struct ltt_kernel_session *ksess, int wpipe)
        }
 
        /* Open kernel metadata stream */
-       if (ksess->metadata_stream_fd < 0) {
+       if (ksess->metadata && ksess->metadata_stream_fd < 0) {
                ret = kernel_open_metadata_stream(ksess);
                if (ret < 0) {
                        ERR("Kernel create metadata stream failed");
@@ -1742,6 +1743,72 @@ find_error:
        return ret;
 }
 
+/*
+ * Command LTTNG_CREATE_SESSION_SNAPSHOT processed by the client thread.
+ */
+int cmd_create_session_snapshot(char *name, struct lttng_uri *uris,
+               size_t nb_uri, lttng_sock_cred *creds)
+{
+       int ret;
+       struct ltt_session *session;
+       struct snapshot_output *new_output = NULL;
+
+       assert(name);
+       assert(creds);
+
+       /*
+        * Create session in no output mode with URIs set to NULL. The uris we've
+        * received are for a default snapshot output if one.
+        */
+       ret = cmd_create_session_uri(name, NULL, 0, creds);
+       if (ret != LTTNG_OK) {
+               goto error;
+       }
+
+       /* Get the newly created session pointer back. This should NEVER fail. */
+       session = session_find_by_name(name);
+       assert(session);
+
+       /* Flag session for snapshot mode. */
+       session->snapshot_mode = 1;
+
+       /* Skip snapshot output creation if no URI is given. */
+       if (nb_uri == 0) {
+               goto end;
+       }
+
+       new_output = snapshot_output_alloc();
+       if (!new_output) {
+               ret = LTTNG_ERR_NOMEM;
+               goto error_snapshot_alloc;
+       }
+
+       ret = snapshot_output_init_with_uri(DEFAULT_SNAPSHOT_MAX_SIZE, NULL,
+                       uris, nb_uri, session->consumer, new_output, &session->snapshot);
+       if (ret < 0) {
+               if (ret == -ENOMEM) {
+                       ret = LTTNG_ERR_NOMEM;
+               } else {
+                       ret = LTTNG_ERR_INVALID;
+               }
+               goto error_snapshot;
+       }
+
+       rcu_read_lock();
+       snapshot_add_output(&session->snapshot, new_output);
+       rcu_read_unlock();
+
+end:
+       return LTTNG_OK;
+
+error_snapshot:
+       snapshot_output_destroy(new_output);
+error_snapshot_alloc:
+       session_destroy(session);
+error:
+       return ret;
+}
+
 /*
  * Command LTTNG_DESTROY_SESSION processed by the client thread.
  */
@@ -2374,8 +2441,8 @@ static int set_relayd_for_snapshot(struct consumer_output *consumer,
         * snapshot output.
         */
        rcu_read_lock();
-       cds_lfht_for_each_entry(consumer->socks->ht, &iter.iter, socket,
-                       node.node) {
+       cds_lfht_for_each_entry(snap_output->consumer->socks->ht, &iter.iter,
+                       socket, node.node) {
                ret = send_consumer_relayd_sockets(0, session->id,
                                snap_output->consumer, socket);
                if (ret < 0) {
@@ -2403,6 +2470,14 @@ static int record_kernel_snapshot(struct ltt_kernel_session *ksess,
        assert(output);
        assert(session);
 
+       /* Get the datetime for the snapshot output directory. */
+       ret = utils_get_current_time_str("%Y%m%d-%H%M%S", output->datetime,
+                       sizeof(output->datetime));
+       if (!ret) {
+               ret = -EINVAL;
+               goto error;
+       }
+
        if (!output->kernel_sockets_copied) {
                ret = consumer_copy_sockets(output->consumer, ksess->consumer);
                if (ret < 0) {
@@ -2439,6 +2514,14 @@ static int record_ust_snapshot(struct ltt_ust_session *usess,
        assert(output);
        assert(session);
 
+       /* Get the datetime for the snapshot output directory. */
+       ret = utils_get_current_time_str("%Y%m%d-%H%M%S", output->datetime,
+                       sizeof(output->datetime));
+       if (!ret) {
+               ret = -EINVAL;
+               goto error;
+       }
+
        if (!output->ust_sockets_copied) {
                ret = consumer_copy_sockets(output->consumer, usess->consumer);
                if (ret < 0) {
@@ -2555,7 +2638,7 @@ int cmd_snapshot_record(struct ltt_session *session,
                        rcu_read_lock();
                        cds_lfht_for_each_entry(session->snapshot.output_ht->ht,
                                        &iter.iter, sout, node.node) {
-                               ret = record_ust_snapshot(usess, tmp_sout, session, wait);
+                               ret = record_ust_snapshot(usess, sout, session, wait);
                                if (ret < 0) {
                                        rcu_read_unlock();
                                        goto error;