block: Do not strcmp() with NULL uri->scheme

uri_parse(...)->scheme may be NULL. In fact, probably every field may be
NULL, and the callers do test this for all of the other fields but not
for scheme (except for block/gluster.c; block/vxhs.c does not access
that field at all).

We can easily fix this by using g_strcmp0() instead of strcmp().

Cc: qemu-stable@nongnu.org
Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20170613205726.13544-1-mreitz@redhat.com
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

4 files changed, 8 insertions, 8 deletions

diff --git a/block/nbd.c b/block/nbd.c
index e946ea944d..d529305330 100644
--- a/block/nbd.c
+++ b/block/nbd.c
@@ -64,11 +64,11 @@ static int nbd_parse_uri(const char *filename, QDict *options)
     }
 
     /* transport */
-    if (!strcmp(uri->scheme, "nbd")) {
+    if (!g_strcmp0(uri->scheme, "nbd")) {
         is_unix = false;
-    } else if (!strcmp(uri->scheme, "nbd+tcp")) {
+    } else if (!g_strcmp0(uri->scheme, "nbd+tcp")) {
         is_unix = false;
-    } else if (!strcmp(uri->scheme, "nbd+unix")) {
+    } else if (!g_strcmp0(uri->scheme, "nbd+unix")) {
         is_unix = true;
     } else {
         ret = -EINVAL;
diff --git a/block/nfs.c b/block/nfs.c
index 6b8b5b653d..c3c5de0113 100644
--- a/block/nfs.c
+++ b/block/nfs.c
@@ -82,7 +82,7 @@ static int nfs_parse_uri(const char *filename, QDict *options, Error **errp)
         error_setg(errp, "Invalid URI specified");
         goto out;
     }
-    if (strcmp(uri->scheme, "nfs") != 0) {
+    if (g_strcmp0(uri->scheme, "nfs") != 0) {
         error_setg(errp, "URI scheme must be 'nfs'");
         goto out;
     }
diff --git a/block/sheepdog.c b/block/sheepdog.c
index a87ee5facd..08d7b11e9d 100644
--- a/block/sheepdog.c
+++ b/block/sheepdog.c
@@ -1046,11 +1046,11 @@ static void sd_parse_uri(SheepdogConfig *cfg, const char *filename,
     }
 
     /* transport */
-    if (!strcmp(uri->scheme, "sheepdog")) {
+    if (!g_strcmp0(uri->scheme, "sheepdog")) {
         is_unix = false;
-    } else if (!strcmp(uri->scheme, "sheepdog+tcp")) {
+    } else if (!g_strcmp0(uri->scheme, "sheepdog+tcp")) {
         is_unix = false;
-    } else if (!strcmp(uri->scheme, "sheepdog+unix")) {
+    } else if (!g_strcmp0(uri->scheme, "sheepdog+unix")) {
         is_unix = true;
     } else {
         error_setg(&err, "URI scheme must be 'sheepdog', 'sheepdog+tcp',"
diff --git a/block/ssh.c b/block/ssh.c
index bac3453c3e..52964416da 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -204,7 +204,7 @@ static int parse_uri(const char *filename, QDict *options, Error **errp)
         return -EINVAL;
     }
 
-    if (strcmp(uri->scheme, "ssh") != 0) {
+    if (g_strcmp0(uri->scheme, "ssh") != 0) {
         error_setg(errp, "URI scheme must be 'ssh'");
         goto err;
     }