Fix segfault for wlroots based capturing

sunshine/platform/linux/wayland.cpp

@@ -168,7 +168,6 @@ void dmabuf_t::frame(
   next_frame->width     = width;
   next_frame->height    = height;
   next_frame->obj_count = obj_count;
-  next_frame->frame     = frame;
 }
 
 void dmabuf_t::object(
@@ -192,6 +191,8 @@ void dmabuf_t::ready(
   zwlr_export_dmabuf_frame_v1 *frame,
   std::uint32_t tv_sec_hi, std::uint32_t tv_sec_lo, std::uint32_t tv_nsec) {
 
+  zwlr_export_dmabuf_frame_v1_destroy(frame);
+
   current_frame->destroy();
   current_frame = get_next_frame();
 
@@ -201,6 +202,9 @@ void dmabuf_t::ready(
 void dmabuf_t::cancel(
   zwlr_export_dmabuf_frame_v1 *frame,
   zwlr_export_dmabuf_frame_v1_cancel_reason reason) {
+
+  zwlr_export_dmabuf_frame_v1_destroy(frame);
+
   auto next_frame = get_next_frame();
   next_frame->destroy();
 
@@ -208,15 +212,10 @@ void dmabuf_t::cancel(
 }
 
 void frame_t::destroy() {
-  if(frame) {
-    zwlr_export_dmabuf_frame_v1_destroy(frame);
-  }
-
   for(auto x = 0; x < obj_count; ++x) {
     close(fds[x]);
   }
 
-  frame     = nullptr;
   obj_count = 0;
 }
 

sunshine/platform/linux/wayland.h

@@ -22,8 +22,6 @@ public:
   std::uint32_t offsets[4];
   std::uint32_t plane_indices[4];
 
-  zwlr_export_dmabuf_frame_v1 *frame;
-
   void destroy();
 };
 

sunshine/platform/linux/wlgrab.cpp

@@ -16,6 +16,21 @@ struct img_t : public platf::img_t {
   }
 };
 
+class frame_descriptor_t : public egl::img_descriptor_t {
+public:
+  ~frame_descriptor_t() {
+    reset();
+  }
+
+  void reset() {
+    std::for_each_n(fds, obj_count, [](int fd) {
+      close(fd);
+    });
+
+    obj_count = 0;
+  }
+};
+
 class wlr_t : public platf::display_t {
 public:
   int init(platf::mem_type_e hwdevice_type, const std::string &display_name, int framerate) {
@@ -259,7 +274,8 @@ public:
       return status;
     }
 
-    auto img = (egl::img_descriptor_t *)img_out_base;
+    auto img = (frame_descriptor_t *)img_out_base;
+    img->reset();
 
     auto current_frame = dmabuf.current_frame;
 
@@ -275,11 +291,14 @@ public:
     std::copy_n(std::begin(current_frame->offsets), current_frame->obj_count, img->offsets);
     std::copy_n(std::begin(current_frame->strides), current_frame->obj_count, img->strides);
 
+    // Prevent dmabuf from closing the file descriptors.
+    current_frame->obj_count = 0;
+
     return platf::capture_e::ok;
   }
 
   std::shared_ptr<platf::img_t> alloc_img() override {
-    auto img = std::make_shared<egl::img_descriptor_t>();
+    auto img = std::make_shared<frame_descriptor_t>();
 
     img->img_width  = width;
     img->img_height = height;