init

src/x11/meson.build

@@ -0,0 +1,25 @@
+# Copyright © 2017 Intel Corporation
+# SPDX-License-Identifier: MIT
+
+inc_loader_x11 = include_directories('.')
+
+loader_x11_files = files(
+  'x11_display.c',
+)
+
+if with_dri_platform == 'drm' or with_dri_platform == 'pseudo-drm'
+  loader_x11_files += files('x11_dri3.c')
+endif
+
+libloader_x11 = static_library(
+  'loader_x11',
+  loader_x11_files,
+  gnu_symbol_visibility : 'hidden',
+  include_directories : [inc_include, inc_src],
+  dependencies : [
+    idep_mesautil,
+    dep_libdrm, dep_xcb_dri3, dep_xcb_present, dep_xcb_sync, dep_xshmfence,
+    dep_xcb_xfixes, dep_x11
+  ],
+  build_by_default : false,
+)

src/x11/x11_display.c

@@ -0,0 +1,128 @@
+/*
+ * Copyright © 2025 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+#include "x11_display.h"
+
+#include "util/macros.h"
+#include "util/log.h"
+
+#include <stdio.h>
+#include <X11/Xlibint.h>
+
+#ifdef HAVE_SYS_SHM_H
+#include <xcb/shm.h>
+#include <sys/shm.h>
+#endif
+
+bool
+x11_xlib_display_is_thread_safe(Display *dpy)
+{
+   static bool warned = false;
+
+   /* 'lock_fns' is the XLockDisplay function pointer of the X11 display 'dpy'.
+    * It will be NULL if XInitThreads wasn't called.
+    */
+   if (likely(dpy->lock_fns != NULL))
+      return true;
+
+   if (unlikely(!warned)) {
+      fprintf(stderr, "Xlib is not thread-safe.  This should never be the "
+                      "case starting with XLib 1.8.  Either upgrade XLib "
+                      "or call XInitThreads() from your app.\n");
+      warned = true;
+   }
+
+   return false;
+}
+
+#ifdef HAVE_SYS_SHM_H
+bool
+x11_xcb_display_supports_xshm(xcb_connection_t *con)
+{
+   xcb_generic_error_t *error;
+   xcb_query_extension_cookie_t shm_cookie;
+   xcb_query_extension_reply_t *shm_reply;
+   bool has_mit_shm;
+   int shmid;
+   void *shm_addr = (void *) -1;
+   xcb_shm_seg_t shm_seg;
+   bool ret = true;
+
+   shm_cookie = xcb_query_extension(con, 7, "MIT-SHM");
+   shm_reply = xcb_query_extension_reply(con, shm_cookie, NULL);
+
+   has_mit_shm = shm_reply && shm_reply->present;
+   free(shm_reply);
+   if (!has_mit_shm)
+      return false;
+
+   /* Check if we're a remote client by attempting to detach segment 0.
+    * Remote clients will get BadRequest, local clients get BadValue,
+    * since 'info' has an invalid segment name.
+    */
+   if ((error = xcb_request_check(con,
+                                  xcb_shm_detach_checked(con, 0)))) {
+      bool is_remote = error->error_code == BadRequest;
+      free(error);
+      if (is_remote)
+         return false;
+    }
+
+   /* We're a local client. Now verify we can actually attach SHM.
+    * In some container setups, the X server reports MIT-SHM support
+    * but the client lacks permission to attach shared memory.
+    */
+   shmid = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0600);
+   if (shmid < 0) {
+      mesa_logd("shared memory allocation error: %s", strerror(errno));
+      return false;
+   }
+
+   shm_addr = shmat(shmid, NULL, 0);
+   if (shm_addr == (void *) -1) {
+      mesa_logd("shmat failed: %s", strerror(errno));
+      ret = false;
+      goto check_xshm_cleanup;
+   }
+
+   shm_seg = xcb_generate_id(con);
+   error = xcb_request_check(con,
+                             xcb_shm_attach_checked(con,
+                                                    shm_seg, shmid, 0));
+   if (error) {
+      mesa_logd("Failed to attach to x11 shm with error: %u", error->error_code);
+      free(error);
+      ret = false;
+      goto check_xshm_cleanup;
+   }
+
+   /* Only detach if it was attached successfully */
+   xcb_shm_detach(con, shm_seg);
+
+check_xshm_cleanup:
+   if (shm_addr != (void *) -1)
+      shmdt(shm_addr);
+   shmctl(shmid, IPC_RMID, NULL);
+
+   return ret;
+}
+#endif

src/x11/x11_display.h

@@ -0,0 +1,47 @@
+/*
+ * Copyright © 2025 Collabora, Ltd.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#ifndef _UTIL_X11_H
+#define _UTIL_X11_H
+
+#include <stdbool.h>
+#include <X11/Xlib.h>
+#ifdef HAVE_SYS_SHM_H
+#include <xcb/xcb.h>
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+bool x11_xlib_display_is_thread_safe(Display *dpy);
+
+#ifdef HAVE_SYS_SHM_H
+bool x11_xcb_display_supports_xshm(xcb_connection_t *con);
+#endif
+
+#ifdef __cplusplus
+} /* extern C */
+#endif
+
+#endif /* _UTIL_X11_H */

src/x11/x11_dri3.c

@@ -0,0 +1,146 @@
+/*
+ * Copyright © 2013 Keith Packard
+ * Copyright © 2015 Boyan Ding
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#include "x11_dri3.h"
+
+#include <stdbool.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <xcb/xcb.h>
+#include <xcb/dri3.h>
+#include <xcb/present.h>
+#include <xcb/xfixes.h>
+
+/** x11_dri3_open
+ *
+ * Wrapper around xcb_dri3_open
+ */
+int
+x11_dri3_open(xcb_connection_t *conn,
+                 xcb_window_t root,
+                 uint32_t provider)
+{
+   xcb_dri3_open_cookie_t       cookie;
+   xcb_dri3_open_reply_t        *reply;
+   xcb_xfixes_query_version_cookie_t fixes_cookie;
+   xcb_xfixes_query_version_reply_t *fixes_reply;
+   int                          fd;
+   const xcb_query_extension_reply_t *extension;
+
+   xcb_prefetch_extension_data(conn, &xcb_dri3_id);
+   extension = xcb_get_extension_data(conn, &xcb_dri3_id);
+   if (!(extension && extension->present))
+      return -1;
+
+   cookie = xcb_dri3_open(conn,
+                          root,
+                          provider);
+
+   reply = xcb_dri3_open_reply(conn, cookie, NULL);
+
+   if (!reply || reply->nfd != 1) {
+      free(reply);
+      return -1;
+   }
+
+   fd = xcb_dri3_open_reply_fds(conn, reply)[0];
+   free(reply);
+   fcntl(fd, F_SETFD, fcntl(fd, F_GETFD) | FD_CLOEXEC);
+
+   /* let the server know our xfixes level */
+   fixes_cookie = xcb_xfixes_query_version(conn,
+                                           XCB_XFIXES_MAJOR_VERSION,
+                                           XCB_XFIXES_MINOR_VERSION);
+   fixes_reply = xcb_xfixes_query_version_reply(conn, fixes_cookie, NULL);
+   if (fixes_reply->major_version < 2) {
+      close(fd);
+      fd = -1;
+   }
+   free(fixes_reply);
+
+   return fd;
+}
+
+/* Only request versions of these protocols which we actually support. */
+#define DRI3_SUPPORTED_MAJOR 1
+#define PRESENT_SUPPORTED_MAJOR 1
+
+#ifdef HAVE_X11_DRM
+#define DRI3_SUPPORTED_MINOR 2
+#define PRESENT_SUPPORTED_MINOR 2
+#else
+#define PRESENT_SUPPORTED_MINOR 0
+#define DRI3_SUPPORTED_MINOR 0
+#endif
+
+bool
+x11_dri3_has_multibuffer(xcb_connection_t *c)
+{
+   xcb_dri3_query_version_cookie_t      dri3_cookie;
+   xcb_dri3_query_version_reply_t       *dri3_reply;
+   xcb_present_query_version_cookie_t   present_cookie;
+   xcb_present_query_version_reply_t    *present_reply;
+   xcb_generic_error_t                  *error;
+   const xcb_query_extension_reply_t    *extension;
+
+   xcb_prefetch_extension_data(c, &xcb_dri3_id);
+   xcb_prefetch_extension_data(c, &xcb_present_id);
+
+   extension = xcb_get_extension_data(c, &xcb_dri3_id);
+   if (!(extension && extension->present))
+      return false;
+
+   extension = xcb_get_extension_data(c, &xcb_present_id);
+   if (!(extension && extension->present))
+      return false;
+
+   dri3_cookie = xcb_dri3_query_version(c,
+                                        DRI3_SUPPORTED_MAJOR,
+                                        DRI3_SUPPORTED_MINOR);
+   present_cookie = xcb_present_query_version(c,
+                                              PRESENT_SUPPORTED_MAJOR,
+                                              PRESENT_SUPPORTED_MINOR);
+
+   dri3_reply = xcb_dri3_query_version_reply(c, dri3_cookie, &error);
+   if (!dri3_reply) {
+      free(error);
+      return false;
+   }
+
+   int dri3Major = dri3_reply->major_version;
+   int dri3Minor = dri3_reply->minor_version;
+   free(dri3_reply);
+
+   present_reply = xcb_present_query_version_reply(c, present_cookie, &error);
+   if (!present_reply) {
+      free(error);
+      return false;
+   }
+   int presentMajor = present_reply->major_version;
+   int presentMinor = present_reply->minor_version;
+   free(present_reply);
+
+   return (presentMajor > 1 || (presentMajor == 1 && presentMinor >= 2)) &&
+      (dri3Major > 1 || (dri3Major == 1 && dri3Minor >= 2));
+}

src/x11/x11_dri3.h

@@ -0,0 +1,34 @@
+/*
+ * Copyright © 2013 Keith Packard
+ * Copyright © 2015 Boyan Ding
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ */
+
+#ifndef LOADER_X11_H
+#define LOADER_X11_H
+
+#include <xcb/xcb.h>
+#include <inttypes.h>
+#include <stdbool.h>
+
+int x11_dri3_open(xcb_connection_t *conn, xcb_window_t root, uint32_t provider);
+bool x11_dri3_has_multibuffer(xcb_connection_t *c);
+
+#endif