From: David Goulet <dgoulet@efficios.com>
Date: Fri, 28 Jun 2013 20:13:53 +0000 (-0400)
Subject: Fix: kernel snapshot metadata handling and error paths
X-Git-Tag: v2.3.0-rc1~82
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=d771f8323f5f8964145e149502d6dc8d8cac8745;p=lttng-tools.git

Fix: kernel snapshot metadata handling and error paths

Signed-off-by: David Goulet <dgoulet@efficios.com>
---

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index ada5594b7..02198bd1b 100644
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -363,9 +363,12 @@ end:
 int lttng_kconsumer_snapshot_metadata(uint64_t key, char *path,
 		uint64_t relayd_id, struct lttng_consumer_local_data *ctx)
 {
+	int ret, use_relayd = 0;
+	ssize_t ret_read;
 	struct lttng_consumer_channel *metadata_channel;
 	struct lttng_consumer_stream *metadata_stream;
-	int ret;
+
+	assert(ctx);
 
 	DBG("Kernel consumer snapshot metadata with key %" PRIu64 " at path %s",
 			key, path);
@@ -374,58 +377,66 @@ int lttng_kconsumer_snapshot_metadata(uint64_t key, char *path,
 
 	metadata_channel = consumer_find_channel(key);
 	if (!metadata_channel) {
-		ERR("Snapshot kernel metadata channel not found for key %lu", key);
+		ERR("Kernel snapshot metadata not found for key %" PRIu64, key);
 		ret = -1;
-		goto end;
+		goto error;
 	}
 
 	metadata_stream = metadata_channel->metadata_stream;
 	assert(metadata_stream);
 
+	/* Flag once that we have a valid relayd for the stream. */
 	if (relayd_id != (uint64_t) -1ULL) {
+		use_relayd = 1;
+	}
+
+	if (use_relayd) {
 		ret = send_relayd_stream(metadata_stream, path);
 		if (ret < 0) {
-			ERR("sending stream to relayd");
+			goto error;
 		}
-		DBG("Stream %s sent to the relayd", metadata_stream->name);
 	} else {
 		ret = utils_create_stream_file(path, metadata_stream->name,
 				metadata_stream->chan->tracefile_size,
 				metadata_stream->tracefile_count_current,
 				metadata_stream->uid, metadata_stream->gid);
 		if (ret < 0) {
-			goto end;
+			goto error;
 		}
 		metadata_stream->out_fd = ret;
 	}
 
-	ret = 0;
-	while (ret >= 0) {
-		ret = lttng_kconsumer_read_subbuffer(metadata_stream, ctx);
-		if (ret < 0) {
-			if (ret != -EPERM) {
-				ERR("Kernel snapshot reading subbuffer");
-				goto end;
+	do {
+		ret_read = lttng_kconsumer_read_subbuffer(metadata_stream, ctx);
+		if (ret_read < 0) {
+			if (ret_read != -EPERM) {
+				ERR("Kernel snapshot reading metadata subbuffer (ret: %ld)",
+						ret_read);
+				goto error;
 			}
-			/* "ret" is negative at this point so we will exit the loop. */
+			/* ret_read is negative at this point so we will exit the loop. */
 			continue;
 		}
-	}
+	} while (ret_read >= 0);
 
-	if (relayd_id == (uint64_t) -1ULL) {
+	if (use_relayd) {
+		close_relayd_stream(metadata_stream);
+		metadata_stream->net_seq_idx = (uint64_t) -1ULL;
+	} else {
 		ret = close(metadata_stream->out_fd);
 		if (ret < 0) {
-			PERROR("Kernel consumer snapshot close out_fd");
-			goto end;
+			PERROR("Kernel consumer snapshot metadata close out_fd");
+			/*
+			 * Don't go on error here since the snapshot was successful at this
+			 * point but somehow the close failed.
+			 */
 		}
 		metadata_stream->out_fd = -1;
-	} else {
-		close_relayd_stream(metadata_stream);
-		metadata_stream->net_seq_idx = (uint64_t) -1ULL;
 	}
 
 	ret = 0;
-end:
+
+error:
 	rcu_read_unlock();
 	return ret;
 }
@@ -568,20 +579,15 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 		/* First send a status message before receiving the fds. */
 		ret = consumer_send_status_msg(sock, ret_code);
 		if (ret < 0) {
-			/*
-			 * Somehow, the session daemon is not responding
-			 * anymore.
-			 */
+			/* Somehow, the session daemon is not responding anymore. */
 			goto error_fatal;
 		}
 		if (ret_code != LTTNG_OK) {
-			/*
-			 * Channel was not found.
-			 */
+			/* Channel was not found. */
 			goto end_nosignal;
 		}
 
-		/* block */
+		/* Blocking call */
 		if (lttng_consumer_poll_socket(consumer_sockpoll) < 0) {
 			rcu_read_unlock();
 			return -EINTR;
@@ -627,6 +633,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 			}
 			goto end_nosignal;
 		}
+
 		new_stream->chan = channel;
 		new_stream->wait_fd = fd;
 		switch (channel->output) {
@@ -664,7 +671,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 		if (ctx->on_recv_stream) {
 			ret = ctx->on_recv_stream(new_stream);
 			if (ret < 0) {
-				consumer_del_stream(new_stream, NULL);
+				consumer_stream_free(new_stream);
 				goto end_nosignal;
 			}
 		}
@@ -685,7 +692,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 
 		ret = send_relayd_stream(new_stream, NULL);
 		if (ret < 0) {
-			consumer_del_stream(new_stream, NULL);
+			consumer_stream_free(new_stream);
 			goto end_nosignal;
 		}
 
@@ -701,7 +708,7 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 			ERR("Consumer write %s stream to pipe %d",
 					new_stream->metadata_flag ? "metadata" : "data",
 					lttng_pipe_get_writefd(stream_pipe));
-			consumer_del_stream(new_stream, NULL);
+			consumer_stream_free(new_stream);
 			goto end_nosignal;
 		}