[PATCH] copy.c: make copy_fd preserve meaningful errno

From: Stefan Beller <sbeller@google.com>
Date: Nov 17, 2014, 22:14 UTC
Message-ID: <1416262453-30349-1-git-send-email-sbeller@google.com>

From: Ronnie Sahlberg <sahlberg@google.com>

Update copy_fd to return a meaningful errno on failure and also preserve the existing errno variable.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
---
As announced in [1], I'm going to take over the 
ref-transactions-reflog series by Ronnie Sahlberg.

This patch was sent previously to the list as part of that series[2], but it seems to be unrelated to me.

Thanks, Stefan

[1] http://www.mail-archive.com/git@vger.kernel.org/msg61051.html
[2] http://www.spinics.net/lists/git/msg240784.html
 copy.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/copy.c b/copy.c
index f2970ec..a8d366e 100644
--- a/copy.c
+++ b/copy.c
@@ -8,12 +8,17 @@ int copy_fd(int ifd, int ofd)
 		if (!len)
 			break;
 		if (len < 0) {
-			return error("copy-fd: read returned %s",
-				     strerror(errno));
+			int save_errno = errno;
+			error("copy-fd: read returned %s", strerror(errno));
+			errno = save_errno;
+			return -1;
+		}
+		if (write_in_full(ofd, buffer, len) < 0) {
+			int save_errno = errno;
+			error("copy-fd: write returned %s", strerror(errno));
+			errno = save_errno;
+			return -1;
 		}
-		if (write_in_full(ofd, buffer, len) < 0)
-			return error("copy-fd: write returned %s",
-				     strerror(errno));
 	}
 	return 0;
 }

-- 
2.2.0.rc1.24.g562add4