CURLOPT_BUFFERSIZE: support enlarging receive buffer

Replace use of fixed macro BUFSIZE to define the size of the receive
buffer.  Reappropriate CURLOPT_BUFFERSIZE to include enlarging receive
buffer size.  Upon setting, resize buffer if larger than the current
default size up to a MAX_BUFSIZE (512KB). This can benefit protocols
like SFTP.

Closes #1222

1 files changed, 6 insertions, 0 deletions

diff --git a/lib/easy.c b/lib/easy.c
index 1242369d5..bed94a444 100644
--- a/lib/easy.c
+++ b/lib/easy.c
@@ -870,6 +870,11 @@ struct Curl_easy *curl_easy_duphandle(struct Curl_easy *data)
    * get setup on-demand in the code, as that would probably decrease
    * the likeliness of us forgetting to init a buffer here in the future.
    */
+  outcurl->set.buffer_size = data->set.buffer_size;
+  outcurl->state.buffer = malloc(CURL_BUFSIZE(outcurl->set.buffer_size) + 1);
+  if(!outcurl->state.buffer)
+    goto fail;
+
   outcurl->state.headerbuff = malloc(HEADERSIZE);
   if(!outcurl->state.headerbuff)
     goto fail;
@@ -940,6 +945,7 @@ struct Curl_easy *curl_easy_duphandle(struct Curl_easy *data)
   if(outcurl) {
     curl_slist_free_all(outcurl->change.cookielist);
     outcurl->change.cookielist = NULL;
+    Curl_safefree(outcurl->state.buffer);
     Curl_safefree(outcurl->state.headerbuff);
     Curl_safefree(outcurl->change.url);
     Curl_safefree(outcurl->change.referer);