[Qemu-block] [PATCH] qemu-img / curl: When fetching Content-Size use GET instead of HEAD.

[Boris Schrijver]

Hi all,

I was testing out the "qemu-img info/convert" options in combination with
"http/https" when I stumbled upon this issue. When "qemu-img info/convert" tries
to collect the file info it will first try to fetch the Content-Size of the
remote file. It does a HEAD request and after a GET request for the correct
range.

The HEAD request is an issue. Because when you've got a pre-signed url, for
example from S3, which INCLUDES the REQUEST METHOD in it's signature, you'll get
a 403 Forbidden.

It's is therefore better to use only the GET request method, and discard the
body at the first call.

Please review! I'll be ready for answers!

[PATCH] qemu-img / curl: When fetching Content-Size use GET instead of HEAD.

A server can respond different to both methods, or can block one of the two.
---
 block/curl.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/block/curl.c b/block/curl.c
index 8994182..2e74c32 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -594,11 +594,11 @@ static int curl_open(BlockDriverState *bs, QDict *options,
int flags,
     // Get file size
 
     s->accept_range = false;
-    curl_easy_setopt(state->curl, CURLOPT_NOBODY, 1);
+    curl_easy_setopt(state->curl, CURLOPT_HTTPGET, 1);
     curl_easy_setopt(state->curl, CURLOPT_HEADERFUNCTION,
                      curl_header_cb);
     curl_easy_setopt(state->curl, CURLOPT_HEADERDATA, s);
-    if (curl_easy_perform(state->curl))
+    if (curl_easy_perform(state->curl) != 23)
         goto out;
     curl_easy_getinfo(state->curl, CURLINFO_CONTENT_LENGTH_DOWNLOAD, &d);
     if (d)
-- 
2.1.4

-- 

Met vriendelijke groet / Kind regards,

Boris Schrijver

PCextreme B.V.

http://www.pcextreme.nl/contact
Tel direct: +31 (0) 118 700 215