ivshmem: use little-endian int64_t for the protocol

The current ivshmem protocol uses 'long' for integers. But the
sizeof(long) depends on the host and the endianess is not defined, which
may cause portability troubles.

Instead, switch to using little-endian int64_t. This breaks the
protocol, except on x64 little-endian host where this change
should be compatible.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Claudio Fontana <claudio.fontana@huawei.com>

2 files changed, 8 insertions, 7 deletions

diff --git a/contrib/ivshmem-server/ivshmem-server.c b/contrib/ivshmem-server/ivshmem-server.c
index e8693dec3c..5e5239ce45 100644
--- a/contrib/ivshmem-server/ivshmem-server.c
+++ b/contrib/ivshmem-server/ivshmem-server.c
@@ -33,7 +33,7 @@
 
 /* send message to a client unix socket */
 static int
-ivshmem_server_send_one_msg(int sock_fd, long peer_id, int fd)
+ivshmem_server_send_one_msg(int sock_fd, int64_t peer_id, int fd)
 {
     int ret;
     struct msghdr msg;
@@ -44,6 +44,7 @@ ivshmem_server_send_one_msg(int sock_fd, long peer_id, int fd)
     } msg_control;
     struct cmsghdr *cmsg;
 
+    peer_id = GINT64_TO_LE(peer_id);
     iov[0].iov_base = &peer_id;
     iov[0].iov_len = sizeof(peer_id);
 
@@ -79,7 +80,7 @@ ivshmem_server_free_peer(IvshmemServer *server, IvshmemServerPeer *peer)
     unsigned vector;
     IvshmemServerPeer *other_peer;
 
-    IVSHMEM_SERVER_DEBUG(server, "free peer %ld\n", peer->id);
+    IVSHMEM_SERVER_DEBUG(server, "free peer %" PRId64 "\n", peer->id);
     close(peer->sock_fd);
     QTAILQ_REMOVE(&server->peer_list, peer, next);
 
@@ -209,7 +210,7 @@ ivshmem_server_handle_new_conn(IvshmemServer *server)
     }
 
     QTAILQ_INSERT_TAIL(&server->peer_list, peer, next);
-    IVSHMEM_SERVER_DEBUG(server, "new peer id = %ld\n",
+    IVSHMEM_SERVER_DEBUG(server, "new peer id = %" PRId64 "\n",
                          peer->id);
     return 0;
 
@@ -459,7 +460,7 @@ ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd)
 
 /* lookup peer from its id */
 IvshmemServerPeer *
-ivshmem_server_search_peer(IvshmemServer *server, long peer_id)
+ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id)
 {
     IvshmemServerPeer *peer;
 
@@ -480,7 +481,7 @@ ivshmem_server_dump(const IvshmemServer *server)
 
     /* dump peers */
     QTAILQ_FOREACH(peer, &server->peer_list, next) {
-        printf("peer_id = %ld\n", peer->id);
+        printf("peer_id = %" PRId64 "\n", peer->id);
 
         for (vector = 0; vector < peer->vectors_count; vector++) {
             printf("  vector %d is enabled (fd=%d)\n", vector,
diff --git a/contrib/ivshmem-server/ivshmem-server.h b/contrib/ivshmem-server/ivshmem-server.h
index 89c905fa63..c9359a0a8a 100644
--- a/contrib/ivshmem-server/ivshmem-server.h
+++ b/contrib/ivshmem-server/ivshmem-server.h
@@ -51,7 +51,7 @@
 typedef struct IvshmemServerPeer {
     QTAILQ_ENTRY(IvshmemServerPeer) next;    /**< next in list*/
     int sock_fd;                             /**< connected unix sock */
-    long id;                                 /**< the id of the peer */
+    int64_t id;                              /**< the id of the peer */
     EventNotifier vectors[IVSHMEM_SERVER_MAX_VECTORS]; /**< one per vector */
     unsigned vectors_count;                  /**< number of vectors */
 } IvshmemServerPeer;
@@ -155,7 +155,7 @@ int ivshmem_server_handle_fds(IvshmemServer *server, fd_set *fds, int maxfd);
  * Returns:  The peer structure, or NULL if not found
  */
 IvshmemServerPeer *
-ivshmem_server_search_peer(IvshmemServer *server, long peer_id);
+ivshmem_server_search_peer(IvshmemServer *server, int64_t peer_id);
 
 /**
  * Dump information of this ivshmem server and its peers on stdout