ivshmem-server: use a uint16 for client ID

In practice, the number of VM is limited to MAXUINT16 in ivshmem, so use
the same limit on the server (removes a theorical infinite loop)

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

2 files changed, 11 insertions, 2 deletions

diff --git a/contrib/ivshmem-server/ivshmem-server.c b/contrib/ivshmem-server/ivshmem-server.c
index 56b5df8ab7..53a51735ee 100644
--- a/contrib/ivshmem-server/ivshmem-server.c
+++ b/contrib/ivshmem-server/ivshmem-server.c
@@ -145,9 +145,18 @@ ivshmem_server_handle_new_conn(IvshmemServer *server)
     peer->sock_fd = newfd;
 
     /* get an unused peer id */
-    while (ivshmem_server_search_peer(server, server->cur_id) != NULL) {
+    /* XXX: this could use id allocation such as Linux IDA, or simply
+     * a free-list */
+    for (i = 0; i < G_MAXUINT16; i++) {
+        if (ivshmem_server_search_peer(server, server->cur_id) == NULL) {
+            break;
+        }
         server->cur_id++;
     }
+    if (i == G_MAXUINT16) {
+        IVSHMEM_SERVER_DEBUG(server, "cannot allocate new client id\n");
+        goto fail;
+    }
     peer->id = server->cur_id++;
 
     /* create eventfd, one per vector */
diff --git a/contrib/ivshmem-server/ivshmem-server.h b/contrib/ivshmem-server/ivshmem-server.h
index bf7de7a7ca..83c751c261 100644
--- a/contrib/ivshmem-server/ivshmem-server.h
+++ b/contrib/ivshmem-server/ivshmem-server.h
@@ -71,7 +71,7 @@ typedef struct IvshmemServer {
     size_t shm_size;                 /**< size of shm */
     int shm_fd;                      /**< shm file descriptor */
     unsigned n_vectors;              /**< number of vectors */
-    long cur_id;                     /**< id to be given to next client */
+    uint16_t cur_id;                 /**< id to be given to next client */
     bool verbose;                    /**< true in verbose mode */
     IvshmemServerPeerList peer_list; /**< list of peers */
 } IvshmemServer;