ipc: verify resume/suspend commands

Calling mpv_resume() too often is considered an API usage violation,
and will trigger an internal assertion somewhere.

1 files changed, 16 insertions, 4 deletions

diff --git a/input/ipc.c b/input/ipc.c
index 3d2a35f558..1fb096842b 100644
--- a/input/ipc.c
+++ b/input/ipc.c
@@ -60,6 +60,8 @@ struct client_arg {
     int client_fd;
 
     bool writable;
+
+    int suspend_counter;
 };
 
 static mpv_node *mpv_node_map_get(mpv_node *src, const char *key)
@@ -409,11 +411,21 @@ static char *json_execute_command(struct client_arg *arg, void *ta_parent,
         rc = mpv_unobserve_property(arg->client,
                                   cmd_node->u.list->values[1].u.int64);
     } else if (!strcmp("suspend", cmd)) {
-        mpv_suspend(arg->client);
-        rc = MPV_ERROR_SUCCESS;
+        if (arg->suspend_counter < INT_MAX) {
+            mpv_suspend(arg->client);
+            arg->suspend_counter++;
+            rc = MPV_ERROR_SUCCESS;
+        } else {
+            rc = MPV_ERROR_INVALID_PARAMETER;
+        }
     } else if (!strcmp("resume", cmd)) {
-        mpv_resume(arg->client);
-        rc = MPV_ERROR_SUCCESS;
+        if (arg->suspend_counter > 0) {
+            mpv_resume(arg->client);
+            arg->suspend_counter--;
+            rc = MPV_ERROR_SUCCESS;
+        } else {
+            rc = MPV_ERROR_INVALID_PARAMETER;
+        }
     } else {
         mpv_node result_node;