dload: unhook error buffer after transfer finishes

Similar to what we did in edd9ed6a, disconnect the relationship with our
stack allocated error buffer from the curl handle. Just as an FTP
connection might have some network chatter on teardown causing the
progress callback to be triggered, we might also hit an error condition
that causes curl to write to our (now out of scope) error buffer.

I'm unable to reproduce FS#26327, but I have a suspicion that this
should fix it.

Signed-off-by: Dave Reisner <dreisner@archlinux.org>
Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 4 insertions, 1 deletions

diff --git a/lib/libalpm/dload.c b/lib/libalpm/dload.c
index 33824be8..83060f97 100644
--- a/lib/libalpm/dload.c
+++ b/lib/libalpm/dload.c
@@ -377,8 +377,11 @@ static int curl_download_internal(struct dload_payload *payload,
 	/* perform transfer */
 	payload->curlerr = curl_easy_perform(curl);
 
-	/* immediately unhook the progress callback */
+	/* disconnect relationships from the curl handle for things that might go out
+	 * of scope, but could still be touched on connection teardown.  This really
+	 * only applies to FTP transfers. See FS#26327 for an example. */
 	curl_easy_setopt(curl, CURLOPT_NOPROGRESS, 1L);
+	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, (char *)NULL);
 
 	/* was it a success? */
 	switch(payload->curlerr) {