[Qemu-devel] [PATCH v2 01/11] curl: introduce CURLSockInfo to BDRVCURLState.

[Fam Zheng <famz@redhat.com>]

We use socket provided by curl in the driver.  Libcurl multi interface
has option CURLMOPT_SOCKETFUNCTION for socket.

Per man 3 curl_multi_setopt:

    ...
    CURLMOPT_SOCKETFUNCTION

    Pass a pointer to a function matching the curl_socket_callback
    prototype. The curl_multi_socket_action(3) function informs the
    application about updates in the socket (file descriptor) status by
    doing none, one, or multiple calls to the curl_socket_callback given in
    the param argument. They update the status with changes since the
    previous time a curl_multi_socket(3) function was called. If the given
    callback pointer is NULL, no callback will be called. Set the callback's
    userp argument with CURLMOPT_SOCKETDATA. See curl_multi_socket(3) for
    more callback details.
    ...

The added structure store information for all the socket returned by
libcurl. The most important field is action, which is used to keep what
actions are needed when this socket's fd handler is called.

Signed-off-by: Fam Zheng <famz@redhat.com>
---
 block/curl.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/block/curl.c b/block/curl.c
index b8935fd..14f4552 100644
--- a/block/curl.c
+++ b/block/curl.c
@@ -75,10 +75,18 @@ typedef struct CURLState
     char in_use;
 } CURLState;
 
+typedef struct CURLSockInfo {
+    curl_socket_t fd;
+    int action;
+    struct BDRVCURLState *s;
+    QLIST_ENTRY(CURLSockInfo) next;
+} CURLSockInfo;
+
 typedef struct BDRVCURLState {
     CURLM *multi;
     size_t len;
     CURLState states[CURL_NUM_STATES];
+    QLIST_HEAD(, CURLSockInfo) socks;
     char *url;
     size_t readahead_size;
 } BDRVCURLState;
@@ -90,7 +98,16 @@ static int curl_aio_flush(void *opaque);
 static int curl_sock_cb(CURL *curl, curl_socket_t fd, int action,
                         void *s, void *sp)
 {
+    BDRVCURLState *bs = (BDRVCURLState *)s;
     DPRINTF("CURL (AIO): Sock action %d on fd %d\n", action, fd);
+    CURLSockInfo *sock = (CURLSockInfo *)sp;
+    if (!sp) {
+        sock = g_malloc0(sizeof(CURLSockInfo));
+        sock->fd = fd;
+        sock->s = bs;
+        QLIST_INSERT_HEAD(&bs->socks, sock, next);
+        curl_multi_assign(bs->multi, fd, sock);
+    }
     switch (action) {
         case CURL_POLL_IN:
             qemu_aio_set_fd_handler(fd, curl_multi_do, NULL, curl_aio_flush, s);
@@ -462,8 +479,8 @@ static int curl_open(BlockDriverState *bs, QDict *options, int flags)
     // initialize the multi interface!
 
     s->multi = curl_multi_init();
-    curl_multi_setopt( s->multi, CURLMOPT_SOCKETDATA, s); 
-    curl_multi_setopt( s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb ); 
+    curl_multi_setopt(s->multi, CURLMOPT_SOCKETDATA, s);
+    curl_multi_setopt(s->multi, CURLMOPT_SOCKETFUNCTION, curl_sock_cb);
     curl_multi_do(s);
 
     qemu_opts_del(opts);
-- 
1.8.1.4