[Qemu-block] [PATCH for-2.9 2/2] block/curl: Check protocol prefix

[Max Reitz]

If the user has explicitly specified a block driver and thus a protocol,
we have to make sure the URL's protocol prefix matches. Otherwise the
latter will silently override the former which might catch some users by
surprise.

Signed-off-by: Max Reitz <address@hidden>
---
 block/curl.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/block/curl.c b/block/curl.c
index 34dbd335f4..2708d57c2f 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -659,6 +659,7 @@ static int curl_open(BlockDriverState *bs, QDict *options, 
int flags,
     const char *cookie;
     double d;
     const char *secretid;
+    const char *protocol_delimiter;
 
     static int inited = 0;
 
@@ -700,6 +701,15 @@ static int curl_open(BlockDriverState *bs, QDict *options, 
int flags,
         goto out_noclean;
     }
 
+    if (!strstart(file, bs->drv->protocol_name, &protocol_delimiter) ||
+        !strstart(protocol_delimiter, "://", NULL))
+    {
+        error_setg(errp, "%s curl driver cannot handle the URL '%s' (does not "
+                   "start with '%s://')", bs->drv->protocol_name, file,
+                   bs->drv->protocol_name);
+        goto out_noclean;
+    }
+
     s->username = g_strdup(qemu_opt_get(opts, CURL_BLOCK_OPT_USERNAME));
     secretid = qemu_opt_get(opts, CURL_BLOCK_OPT_PASSWORD_SECRET);
 
-- 
2.12.1