Function to probe for Wayland compositor name

Maybe needed to workaround #8236
kovidgoyal · Jan 21, 2025 · 7346aca · 7346aca
1 parent 5335d18
commit 7346aca
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Showing 2 changed files with 35 additions and 0 deletions.
diff --git a/glfw/wl_init.c b/glfw/wl_init.c
@@ -668,6 +668,35 @@ GLFWAPI pid_t glfwWaylandCompositorPID(void) {
     return get_socket_peer_pid(fd);
 }
 
+const char*
+_glfwWaylandCompositorName(void) {
+    static bool probed = false;
+    if (!probed) {
+        probed = true;
+        static const size_t sz = 1024;
+        _glfw.wl.compositor_name = malloc(sz);
+        if (!_glfw.wl.compositor_name) return "";
+        char *ans = _glfw.wl.compositor_name; ans[0] = 0;
+        pid_t cpid = glfwWaylandCompositorPID();
+        if (cpid < 0) return ans;
+        snprintf(ans, sz, "/proc/%d/cmdline", cpid);
+        int fd = open(ans, O_RDONLY | O_CLOEXEC);
+        if (fd < 0) {
+            ans[0] = 0;
+        } else {
+            ssize_t n;
+            while (true) {
+                n = read(fd, ans, sz-1);
+                if (n < 0 && errno == EINTR) continue;
+                close(fd); break;
+            }
+            ans[n < 0 ? 0 : n] = 0;
+        }
+    }
+    return _glfw.wl.compositor_name ? _glfw.wl.compositor_name : "";
+}
+
+
 //////////////////////////////////////////////////////////////////////////
 //////                       GLFW platform API                      //////
 //////////////////////////////////////////////////////////////////////////
@@ -876,6 +905,10 @@ void _glfwPlatformTerminate(void)
         wl_display_disconnect(_glfw.wl.display);
     }
     finalizePollData(&_glfw.wl.eventLoopData);
+    if (_glfw.wl.compositor_name) {
+        free(_glfw.wl.compositor_name);
+        _glfw.wl.compositor_name = NULL;
+    }
 }
 
 #define GLFW_LOOP_BACKEND wl

diff --git a/glfw/wl_platform.h b/glfw/wl_platform.h
@@ -389,6 +389,7 @@ typedef struct _GLFWlibraryWayland
     size_t dataOffersCounter;
     _GLFWWaylandDataOffer dataOffers[8];
     bool has_preferred_buffer_scale;
+    char *compositor_name;
 } _GLFWlibraryWayland;
 
 // Wayland-specific per-monitor data
@@ -432,6 +433,7 @@ int _glfwWaylandIntegerWindowScale(_GLFWwindow*);
 void animateCursorImage(id_type timer_id, void *data);
 struct wl_cursor* _glfwLoadCursor(GLFWCursorShape, struct wl_cursor_theme*);
 void destroy_data_offer(_GLFWWaylandDataOffer*);
+const char* _glfwWaylandCompositorName(void);
 
 typedef struct wayland_cursor_shape {
     int which; const char *name;