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From: Cong Wang <amwang@redhat.com>
To: util-linux@vger.kernel.org
Cc: Cong Wang <xiyou.wangcong@gmail.com>, Karel Zak <kzak@redhat.com>
Subject: [Patch] lib/sysfs.c: check if cxt->dir_path is NULL in sysfs_readlink()
Date: Wed, 20 Jun 2012 16:32:00 +0800
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From: Cong Wang <xiyou.wangcong@gmail.com>

cxt->dir_path could be NULL, for example, when sysfs_init() fails,
check this before calling readlink()/readlink_at().

Cc: Karel Zak <kzak@redhat.com>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>

---
diff --git a/lib/sysfs.c b/lib/sysfs.c
index 312191f..b4fb7cd 100644
--- a/lib/sysfs.c
+++ b/lib/sysfs.c
@@ -220,6 +220,9 @@ static int sysfs_open(struct sysfs_cxt *cxt, const char *attr)
 ssize_t sysfs_readlink(struct sysfs_cxt *cxt, const char *attr,
 		   char *buf, size_t bufsiz)
 {
+	if (!cxt->dir_path)
+		return -1;
+
 	if (attr)
 		return readlink_at(cxt->dir_fd, cxt->dir_path, attr, buf, bufsiz);