[PATCH 15/24] tools/xenstore: get_handle: use "goto err" error handling style

From: Ian Jackson <ian.jackson@eu.citrix.com>
To: xen-devel@lists.xensource.com
Cc: Ross Lagerwall <ross.lagerwall@citrix.com>,
	Stefano Stabellini <sstabellini@kernel.org>,
	Wei Liu <wei.liu2@citrix.com>,
	Ian Jackson <Ian.Jackson@eu.citrix.com>
Subject: [PATCH 15/24] tools/xenstore: get_handle: use "goto err" error handling style
Date: Wed, 4 Oct 2017 16:57:21 +0100	[thread overview]
Message-ID: <1507132650-25376-16-git-send-email-ian.jackson@eu.citrix.com> (raw)
In-Reply-To: <1507132650-25376-1-git-send-email-ian.jackson@eu.citrix.com>

Replace the ad-hoc exit clauses with the error handling style where
  - local variables contain either things to be freed, or sentinels
  - all error exits go via an "err" label which frees everything

Signed-off-by: Ian Jackson <Ian.Jackson@eu.citrix.com>
Acked-by: Wei Liu <wei.liu2@citrix.com>
---
 tools/xenstore/xs.c | 21 +++++++++++++--------
 1 file changed, 13 insertions(+), 8 deletions(-)

diff --git a/tools/xenstore/xs.c b/tools/xenstore/xs.c
index 56caac7..65cba86 100644
--- a/tools/xenstore/xs.c
+++ b/tools/xenstore/xs.c
@@ -226,7 +226,7 @@ static struct xs_handle *get_handle(const char *connect_to)
 	int fd = -1, saved_errno;
 
 	if (stat(connect_to, &buf) != 0)
-		return NULL;
+		goto err;
 
 	if (S_ISSOCK(buf.st_mode))
 		fd = get_socket(connect_to);
@@ -234,15 +234,11 @@ static struct xs_handle *get_handle(const char *connect_to)
 		fd = get_dev(connect_to);
 
 	if (fd == -1)
-		return NULL;
+		goto err;
 
 	h = malloc(sizeof(*h));
-	if (h == NULL) {
-		saved_errno = errno;
-		close(fd);
-		errno = saved_errno;
-		return NULL;
-	}
+	if (h == NULL)
+		goto err;
 
 	memset(h, 0, sizeof(*h));
 
@@ -267,6 +263,15 @@ static struct xs_handle *get_handle(const char *connect_to)
 #endif
 
 	return h;
+
+err:
+	saved_errno = errno;
+
+	if (fd >= 0) close(fd);
+	free(h);
+
+	errno = saved_errno;
+	return NULL;
 }
 
 struct xs_handle *xs_daemon_open(void)
-- 
2.1.4


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