Subject: Re: [PATCH] http.c: use CURLOPT_RANGE for range requests

From: David Turner <[email-masked]>
Date: Fri, 30 Oct 2015 18:43:26 -0400

Please disregard this; I noticed I missed a few instances.  Will reroll
shortly.

On Fri, 2015-10-30 at 18:41 -0400, David Turner wrote:
> A HTTP server is permitted to return a non-range response to a HTTP
> range request (and Apache httpd in fact does this in some cases).
> While libcurl knows how to correctly handle this (by skipping bytes
> before and after the requested range), it only turns on this handling
> if it is aware that a range request is being made.  By manually
> setting the range header instead of using CURLOPT_RANGE, we were
> hiding the fact that this was a range request from libcurl.  This
> could cause corruption.
> 
> Signed-off-by: David Turner <[email-masked]>
> ---
>  http.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/http.c b/http.c
> index 0f924a8..303b388 100644
> --- a/http.c
> +++ b/http.c
> @@ -1202,8 +1202,9 @@ static int http_request(const char *url,
>  			curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION,
>  					 fwrite);
>  			if (posn > 0) {
> -				strbuf_addf(&buf, "Range: bytes=%ld-", posn);
> -				headers = curl_slist_append(headers, buf.buf);
> +				strbuf_addf(&buf, "%ld-", posn);
> +				curl_easy_setopt(slot->curl, CURLOPT_RANGE,
> +						 &buf.buf);
>  				strbuf_reset(&buf);
>  			}
>  		} else