[PATCH] Allow curl to rewind the read buffers

["Martin Storsjö" <martin@martin.st>]

Rewinding of the read buffers may be needed when doing HTTP PUT or POST
(or PROPFIND) with multi-pass authentication methods.

Depending on the HTTP server, the read buffers may or may not need
rewinding. (Apache returns a 401 error immediately before any data has
been read from the buffers, while Lighttpd doesn't reply until all data
has been sent.)

Signed-off-by: Martin Storsjo <martin@martin.st>
---
 http-push.c |   24 ++++++++++++++++++++++++
 http.c      |   19 +++++++++++++++++++
 http.h      |    7 +++++++
 3 files changed, 50 insertions(+), 0 deletions(-)

diff --git a/http-push.c b/http-push.c
index 6ce5a1d..7dc0dd4 100644
--- a/http-push.c
+++ b/http-push.c
@@ -567,6 +567,10 @@ static void start_put(struct transfer_request *request)
 	curl_easy_setopt(slot->curl, CURLOPT_INFILE, &request->buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_INFILESIZE, request->buffer.buf.len);
 	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, fread_buffer);
+#ifndef NO_CURL_IOCTL
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLFUNCTION, ioctl_buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLDATA, &request->buffer);
+#endif
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_null);
 	curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, DAV_PUT);
 	curl_easy_setopt(slot->curl, CURLOPT_UPLOAD, 1);
@@ -1267,6 +1271,10 @@ static struct remote_lock *lock_remote(const char *path, long timeout)
 	curl_easy_setopt(slot->curl, CURLOPT_INFILE, &out_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_INFILESIZE, out_buffer.buf.len);
 	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, fread_buffer);
+#ifndef NO_CURL_IOCTL
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLFUNCTION, ioctl_buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLDATA, &out_buffer);
+#endif
 	curl_easy_setopt(slot->curl, CURLOPT_FILE, &in_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_URL, url);
@@ -1508,6 +1516,10 @@ static void remote_ls(const char *path, int flags,
 	curl_easy_setopt(slot->curl, CURLOPT_INFILE, &out_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_INFILESIZE, out_buffer.buf.len);
 	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, fread_buffer);
+#ifndef NO_CURL_IOCTL
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLFUNCTION, ioctl_buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLDATA, &out_buffer);
+#endif
 	curl_easy_setopt(slot->curl, CURLOPT_FILE, &in_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_URL, url);
@@ -1584,6 +1596,10 @@ static int locking_available(void)
 	curl_easy_setopt(slot->curl, CURLOPT_INFILE, &out_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_INFILESIZE, out_buffer.buf.len);
 	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, fread_buffer);
+#ifndef NO_CURL_IOCTL
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLFUNCTION, ioctl_buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLDATA, &out_buffer);
+#endif
 	curl_easy_setopt(slot->curl, CURLOPT_FILE, &in_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_URL, repo->url);
@@ -1766,6 +1782,10 @@ static int update_remote(unsigned char *sha1, struct remote_lock *lock)
 	curl_easy_setopt(slot->curl, CURLOPT_INFILE, &out_buffer);
 	curl_easy_setopt(slot->curl, CURLOPT_INFILESIZE, out_buffer.buf.len);
 	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, fread_buffer);
+#ifndef NO_CURL_IOCTL
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLFUNCTION, ioctl_buffer);
+	curl_easy_setopt(slot->curl, CURLOPT_IOCTLDATA, &out_buffer);
+#endif
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_null);
 	curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, DAV_PUT);
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, dav_headers);
@@ -1910,6 +1930,10 @@ static void update_remote_info_refs(struct remote_lock *lock)
 		curl_easy_setopt(slot->curl, CURLOPT_INFILE, &buffer);
 		curl_easy_setopt(slot->curl, CURLOPT_INFILESIZE, buffer.buf.len);
 		curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, fread_buffer);
+#ifndef NO_CURL_IOCTL
+		curl_easy_setopt(slot->curl, CURLOPT_IOCTLFUNCTION, ioctl_buffer);
+		curl_easy_setopt(slot->curl, CURLOPT_IOCTLDATA, &buffer);
+#endif
 		curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, fwrite_null);
 		curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, DAV_PUT);
 		curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, dav_headers);
diff --git a/http.c b/http.c
index eae74aa..3e8d548 100644
--- a/http.c
+++ b/http.c
@@ -44,6 +44,25 @@ size_t fread_buffer(void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 	return size;
 }
 
+#ifndef NO_CURL_IOCTL
+curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp)
+{
+	struct buffer *buffer = clientp;
+
+	switch (cmd) {
+	case CURLIOCMD_NOP:
+		return CURLIOE_OK;
+
+	case CURLIOCMD_RESTARTREAD:
+		buffer->posn = 0;
+		return CURLIOE_OK;
+
+	default:
+		return CURLIOE_UNKNOWNCMD;
+	}
+}
+#endif
+
 size_t fwrite_buffer(const void *ptr, size_t eltsize, size_t nmemb, void *buffer_)
 {
 	size_t size = eltsize * nmemb;
diff --git a/http.h b/http.h
index 905b462..26abebe 100644
--- a/http.h
+++ b/http.h
@@ -37,6 +37,10 @@
 #define CURLE_HTTP_RETURNED_ERROR CURLE_HTTP_NOT_FOUND
 #endif
 
+#if LIBCURL_VERSION_NUM < 0x070c03
+#define NO_CURL_IOCTL
+#endif
+
 struct slot_results
 {
 	CURLcode curl_result;
@@ -67,6 +71,9 @@ struct buffer
 extern size_t fread_buffer(void *ptr, size_t eltsize, size_t nmemb, void *strbuf);
 extern size_t fwrite_buffer(const void *ptr, size_t eltsize, size_t nmemb, void *strbuf);
 extern size_t fwrite_null(const void *ptr, size_t eltsize, size_t nmemb, void *strbuf);
+#ifndef NO_CURL_IOCTL
+extern curlioerr ioctl_buffer(CURL *handle, int cmd, void *clientp);
+#endif
 
 /* Slot lifecycle functions */
 extern struct active_request_slot *get_active_slot(void);
-- 
1.6.0.2