[dm-devel] [PATCH 05/33] Invalid error code when using multipathd CLI

[Martin Wilck]

From: Hannes Reinecke <hare at suse.de>

When calling the multipathd CLI we're getting the message

error -1 receiving packet

instead of the actual error number.
Problem is a confusion about the return values between
libmpathcmd and uxsock.c.
uxsock.c is assuming a negative return value to be the errno,
but libmpathcmd is returning -1 on error and setting errno.

Signed-off-by: Hannes Reinecke <hare at suse.com>
---
 libmpathcmd/mpath_cmd.c | 4 ++++
 libmultipath/uxsock.c   | 9 +++++++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/libmpathcmd/mpath_cmd.c b/libmpathcmd/mpath_cmd.c
index 856e6b48..1496b682 100644
--- a/libmpathcmd/mpath_cmd.c
+++ b/libmpathcmd/mpath_cmd.c
@@ -141,7 +141,11 @@ int mpath_recv_reply(int fd, char **reply, unsigned int timeout)
 	*reply = NULL;
 	len = mpath_recv_reply_len(fd, timeout);
 	if (len <= 0)
+		return len;
+	if (len > MAX_REPLY_LEN) {
+		errno = EINVAL;
 		return -1;
+	}
 	*reply = malloc(len);
 	if (!*reply)
 		return -1;
diff --git a/libmultipath/uxsock.c b/libmultipath/uxsock.c
index 492f4b9c..7e5a1449 100644
--- a/libmultipath/uxsock.c
+++ b/libmultipath/uxsock.c
@@ -88,7 +88,9 @@ int ux_socket_listen(const char *name)
  */
 int send_packet(int fd, const char *buf)
 {
-	return mpath_send_cmd(fd, buf);
+	if (mpath_send_cmd(fd, buf) < 0)
+		return -errno;
+	return 0;
 }
 
 static int _recv_packet(int fd, char **buf, unsigned int timeout, ssize_t limit)
@@ -98,8 +100,10 @@ static int _recv_packet(int fd, char **buf, unsigned int timeout, ssize_t limit)
 
 	*buf = NULL;
 	len = mpath_recv_reply_len(fd, timeout);
-	if (len <= 0)
+	if (len == 0)
 		return len;
+	if (len < 0)
+		return -errno;
 	if ((limit > 0) && (len > limit))
 		return -EINVAL;
 	(*buf) = MALLOC(len);
@@ -109,6 +113,7 @@ static int _recv_packet(int fd, char **buf, unsigned int timeout, ssize_t limit)
 	if (err != 0) {
 		FREE(*buf);
 		(*buf) = NULL;
+		return -errno;
 	}
 	return err;
 }
-- 
2.11.0