From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Fri, 24 Feb 2012 19:41:49 +0000 (-0500)
Subject: Fix: lttng UST and kernel consumer: fix ret vs errno mixup
X-Git-Tag: v2.0.0-rc3~24
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=87dc6a9c2c936cf4386043083412c695a914cb36;p=lttng-tools.git

Fix: lttng UST and kernel consumer: fix ret vs errno mixup

- errno should be set to -ret (not the opposite!)
  The main effect is that the perror errors were meaningless.

- errno should always be compared with positive values.
  This was also causing consumerd error handling mistakes.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c
index f32f47b3e..c1ba1405e 100644
--- a/src/common/kernel-consumer/kernel-consumer.c
+++ b/src/common/kernel-consumer/kernel-consumer.c
@@ -58,7 +58,7 @@ int lttng_kconsumer_on_read_subbuffer_mmap(
 	/* get the offset inside the fd to mmap */
 	ret = kernctl_get_mmap_read_offset(fd, &mmap_offset);
 	if (ret != 0) {
-		ret = -errno;
+		errno = -ret;
 		perror("kernctl_get_mmap_read_offset");
 		goto end;
 	}
@@ -68,7 +68,7 @@ int lttng_kconsumer_on_read_subbuffer_mmap(
 		if (ret >= len) {
 			len = 0;
 		} else if (ret < 0) {
-			ret = -errno;
+			errno = -ret;
 			perror("Error in file write");
 			goto end;
 		}
@@ -108,7 +108,7 @@ int lttng_kconsumer_on_read_subbuffer_splice(
 				SPLICE_F_MOVE | SPLICE_F_MORE);
 		DBG("splice chan to pipe ret %ld", ret);
 		if (ret < 0) {
-			ret = errno;
+			errno = -ret;
 			perror("Error in relay splice");
 			goto splice_error;
 		}
@@ -117,7 +117,7 @@ int lttng_kconsumer_on_read_subbuffer_splice(
 				SPLICE_F_MOVE | SPLICE_F_MORE);
 		DBG("splice pipe to file %ld", ret);
 		if (ret < 0) {
-			ret = errno;
+			errno = -ret;
 			perror("Error in file splice");
 			goto splice_error;
 		}
@@ -165,7 +165,7 @@ int lttng_kconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 
 	ret = kernctl_snapshot(infd);
 	if (ret != 0) {
-		ret = errno;
+		errno = -ret;
 		perror("Getting sub-buffer snapshot.");
 	}
 
@@ -187,7 +187,7 @@ int lttng_kconsumer_get_produced_snapshot(
 
 	ret = kernctl_snapshot_get_produced(infd, pos);
 	if (ret != 0) {
-		ret = errno;
+		errno = -ret;
 		perror("kernctl_snapshot_get_produced");
 	}
 
@@ -320,7 +320,6 @@ int lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 	/* Get the next subbuffer */
 	err = kernctl_get_next_subbuf(infd);
 	if (err != 0) {
-		ret = errno;
 		/*
 		 * This is a debug message even for single-threaded consumer,
 		 * because poll() have more relaxed criterions than get subbuf,
@@ -337,7 +336,7 @@ int lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 			/* read the whole subbuffer */
 			err = kernctl_get_padded_subbuf_size(infd, &len);
 			if (err != 0) {
-				ret = errno;
+				errno = -ret;
 				perror("Getting sub-buffer len failed.");
 				goto end;
 			}
@@ -356,7 +355,7 @@ int lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 			/* read the used subbuffer size */
 			err = kernctl_get_padded_subbuf_size(infd, &len);
 			if (err != 0) {
-				ret = errno;
+				errno = -ret;
 				perror("Getting sub-buffer len failed.");
 				goto end;
 			}
@@ -377,7 +376,7 @@ int lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 
 	err = kernctl_put_next_subbuf(infd);
 	if (err != 0) {
-		ret = errno;
+		errno = -ret;
 		if (errno == EFAULT) {
 			perror("Error in unreserving sub buffer\n");
 		} else if (errno == EIO) {
@@ -415,7 +414,7 @@ int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
 
 		ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
 		if (ret != 0) {
-			ret = errno;
+			errno = -ret;
 			perror("kernctl_get_mmap_len");
 			goto error_close_fd;
 		}
diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c
index e81f05041..113682384 100644
--- a/src/common/ust-consumer/ust-consumer.c
+++ b/src/common/ust-consumer/ust-consumer.c
@@ -58,7 +58,7 @@ int lttng_ustconsumer_on_read_subbuffer_mmap(
 	ret = ustctl_get_mmap_read_offset(stream->chan->handle,
 		stream->buf, &mmap_offset);
 	if (ret != 0) {
-		ret = -errno;
+		errno = -ret;
 		perror("ustctl_get_mmap_read_offset");
 		goto end;
 	}
@@ -67,7 +67,7 @@ int lttng_ustconsumer_on_read_subbuffer_mmap(
 		if (ret >= len) {
 			len = 0;
 		} else if (ret < 0) {
-			ret = -errno;
+			errno = -ret;
 			perror("Error in file write");
 			goto end;
 		}
@@ -109,7 +109,7 @@ int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx,
 
 	ret = ustctl_snapshot(stream->chan->handle, stream->buf);
 	if (ret != 0) {
-		ret = errno;
+		errno = -ret;
 		perror("Getting sub-buffer snapshot.");
 	}
 
@@ -131,7 +131,7 @@ int lttng_ustconsumer_get_produced_snapshot(
 	ret = ustctl_snapshot_get_produced(stream->chan->handle,
 			stream->buf, pos);
 	if (ret != 0) {
-		ret = errno;
+		errno = -ret;
 		perror("kernctl_snapshot_get_produced");
 	}
 
@@ -347,7 +347,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
 	if (!stream->hangup_flush_done) {
 		do {
 			readlen = read(stream->wait_fd, &dummy, 1);
-		} while (readlen == -1 && errno == -EINTR);
+		} while (readlen == -1 && errno == EINTR);
 		if (readlen == -1) {
 			ret = readlen;
 			goto end;