X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fkernel-consumer%2Fkernel-consumer.c;h=5a219fc0b6c543d5c0f5270c3febd4ccfb4adb3a;hp=11701aebfb9869b7e6dbac8deb26828bd3d8cebe;hb=c30aaa51f34105a7f20b9ceb39866001843db6e6;hpb=fb3a43a9284f3300e9b66edc2f2c2d2767895423

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index 11701aebf..5a219fc0b 100644
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -118,7 +118,8 @@ int lttng_kconsumer_recv_cmd(struct lttng_consumer_local_data *ctx,
 		new_channel = consumer_allocate_channel(msg.u.channel.channel_key,
 				-1, -1,
 				msg.u.channel.mmap_len,
-				msg.u.channel.max_sb_size);
+				msg.u.channel.max_sb_size,
+				msg.u.channel.nb_init_streams);
 		if (new_channel == NULL) {
 			lttng_consumer_send_error(ctx, LTTCOMM_CONSUMERD_OUTFD_ERROR);
 			goto end_nosignal;
@@ -295,7 +296,7 @@ end_nosignal:
 ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 		struct lttng_consumer_local_data *ctx)
 {
-	unsigned long len;
+	unsigned long len, subbuf_size, padding;
 	int err;
 	ssize_t ret = 0;
 	int infd = stream->wait_fd;
@@ -304,6 +305,7 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 	/* Get the next subbuffer */
 	err = kernctl_get_next_subbuf(infd);
 	if (err != 0) {
+		ret = err;
 		/*
 		 * This is a debug message even for single-threaded consumer,
 		 * because poll() have more relaxed criterions than get subbuf,
@@ -315,60 +317,92 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 		goto end;
 	}
 
+	/* Get the full subbuffer size including padding */
+	err = kernctl_get_padded_subbuf_size(infd, &len);
+	if (err != 0) {
+		errno = -err;
+		perror("Getting sub-buffer len failed.");
+		ret = err;
+		goto end;
+	}
+
 	switch (stream->output) {
-		case LTTNG_EVENT_SPLICE:
-			/* read the whole subbuffer */
-			err = kernctl_get_padded_subbuf_size(infd, &len);
-			if (err != 0) {
-				errno = -ret;
-				perror("Getting sub-buffer len failed.");
-				goto end;
-			}
+	case LTTNG_EVENT_SPLICE:
 
-			/* splice the subbuffer to the tracefile */
-			ret = lttng_consumer_on_read_subbuffer_splice(ctx, stream, len);
-			if (ret != len) {
-				/*
-				 * display the error but continue processing to try
-				 * to release the subbuffer
-				 */
-				ERR("Error splicing to tracefile (ret: %zd != len: %lu)",
-						ret, len);
-			}
+		/*
+		 * XXX: The lttng-modules splice "actor" does not handle copying
+		 * partial pages hence only using the subbuffer size without the
+		 * padding makes the splice fail.
+		 */
+		subbuf_size = len;
+		padding = 0;
 
-			break;
-		case LTTNG_EVENT_MMAP:
-			/* read the used subbuffer size */
-			err = kernctl_get_padded_subbuf_size(infd, &len);
-			if (err != 0) {
-				errno = -ret;
-				perror("Getting sub-buffer len failed.");
-				goto end;
-			}
-			/* write the subbuffer to the tracefile */
-			ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
-			if (ret != len) {
-				/*
-				 * display the error but continue processing to try
-				 * to release the subbuffer
-				 */
-				ERR("Error writing to tracefile");
-			}
-			break;
-		default:
-			ERR("Unknown output method");
-			ret = -1;
+		/* splice the subbuffer to the tracefile */
+		ret = lttng_consumer_on_read_subbuffer_splice(ctx, stream, subbuf_size,
+				padding);
+		/*
+		 * XXX: Splice does not support network streaming so the return value
+		 * is simply checked against subbuf_size and not like the mmap() op.
+		 */
+		if (ret != subbuf_size) {
+			/*
+			 * display the error but continue processing to try
+			 * to release the subbuffer
+			 */
+			ERR("Error splicing to tracefile (ret: %zd != len: %lu)",
+					ret, subbuf_size);
+		}
+		break;
+	case LTTNG_EVENT_MMAP:
+		/* Get subbuffer size without padding */
+		err = kernctl_get_subbuf_size(infd, &subbuf_size);
+		if (err != 0) {
+			errno = -err;
+			perror("Getting sub-buffer len failed.");
+			ret = err;
+			goto end;
+		}
+
+		/* Make sure the tracer is not gone mad on us! */
+		assert(len >= subbuf_size);
+
+		padding = len - subbuf_size;
+
+		/* write the subbuffer to the tracefile */
+		ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, subbuf_size,
+				padding);
+		/*
+		 * The mmap operation should write subbuf_size amount of data when
+		 * network streaming or the full padding (len) size when we are _not_
+		 * streaming.
+		 */
+		if ((ret != subbuf_size && stream->net_seq_idx != -1) ||
+				(ret != len && stream->net_seq_idx == -1)) {
+			/*
+			 * Display the error but continue processing to try to release the
+			 * subbuffer
+			 */
+			ERR("Error writing to tracefile "
+					"(ret: %zd != len: %lu != subbuf_size: %lu)",
+					ret, len, subbuf_size);
+		}
+		break;
+	default:
+		ERR("Unknown output method");
+		ret = -1;
 	}
 
 	err = kernctl_put_next_subbuf(infd);
 	if (err != 0) {
-		errno = -ret;
+		errno = -err;
 		if (errno == EFAULT) {
 			perror("Error in unreserving sub buffer\n");
 		} else if (errno == EIO) {
 			/* Should never happen with newer LTTng versions */
 			perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
 		}
+
+		ret = -err;
 		goto end;
 	}