path: root/toolkit/xre/glxtest.cpp

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
 * vim: sw=2 ts=8 et :
 */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

//////////////////////////////////////////////////////////////////////////////
//
// Explanation: See bug 639842. Safely getting GL driver info on X11 is hard,
// because the only way to do that is to create a GL context and call
// glGetString(), but with bad drivers, just creating a GL context may crash.
//
// This file implements the idea to do that in a separate process.
//
// The only non-static function here is fire_glxtest_process(). It creates a
// pipe, publishes its 'read' end as the mozilla::widget::glxtest_pipe global
// variable, forks, and runs that GLX probe in the child process, which runs the
// childgltest() static function. This creates a X connection, a GLX context,
// calls glGetString, and writes that to the 'write' end of the pipe.

#include <cstdio>
#include <cstdlib>
#include <dlfcn.h>
#include <fcntl.h>
#include <unistd.h>

#include "mozilla/Unused.h"
#include "nsAppRunner.h"  // for IsWaylandDisabled on IsX11EGLEnabled
#include "stdint.h"

#ifdef __SUNPRO_CC
#  include <stdio.h>
#endif

#ifdef MOZ_X11
#  include "X11/Xlib.h"
#  include "X11/Xutil.h"
#endif

#ifdef MOZ_WAYLAND
#  include "mozilla/widget/mozwayland.h"
#  include "mozilla/widget/xdg-output-unstable-v1-client-protocol.h"
#endif

#ifdef MOZ_X11
// stuff from glx.h
typedef struct __GLXcontextRec* GLXContext;
typedef XID GLXPixmap;
typedef XID GLXDrawable;
/* GLX 1.3 and later */
typedef struct __GLXFBConfigRec* GLXFBConfig;
typedef XID GLXFBConfigID;
typedef XID GLXContextID;
typedef XID GLXWindow;
typedef XID GLXPbuffer;
#  define GLX_RGBA 4
#  define GLX_RED_SIZE 8
#  define GLX_GREEN_SIZE 9
#  define GLX_BLUE_SIZE 10
#endif

// stuff from gl.h
typedef uint8_t GLubyte;
typedef uint32_t GLenum;
#define GL_VENDOR 0x1F00
#define GL_RENDERER 0x1F01
#define GL_VERSION 0x1F02

// GLX_MESA_query_renderer
// clang-format off
#define GLX_RENDERER_VENDOR_ID_MESA                            0x8183
#define GLX_RENDERER_DEVICE_ID_MESA                            0x8184
#define GLX_RENDERER_VERSION_MESA                              0x8185
#define GLX_RENDERER_ACCELERATED_MESA                          0x8186
#define GLX_RENDERER_VIDEO_MEMORY_MESA                         0x8187
#define GLX_RENDERER_UNIFIED_MEMORY_ARCHITECTURE_MESA          0x8188
#define GLX_RENDERER_PREFERRED_PROFILE_MESA                    0x8189
#define GLX_RENDERER_OPENGL_CORE_PROFILE_VERSION_MESA          0x818A
#define GLX_RENDERER_OPENGL_COMPATIBILITY_PROFILE_VERSION_MESA 0x818B
#define GLX_RENDERER_OPENGL_ES_PROFILE_VERSION_MESA            0x818C
#define GLX_RENDERER_OPENGL_ES2_PROFILE_VERSION_MESA           0x818D
#define GLX_RENDERER_ID_MESA                                   0x818E
// clang-format on

// stuff from egl.h
typedef intptr_t EGLAttrib;
typedef int EGLBoolean;
typedef void* EGLConfig;
typedef void* EGLContext;
typedef void* EGLDeviceEXT;
typedef void* EGLDisplay;
typedef int EGLint;
typedef void* EGLNativeDisplayType;
typedef void* EGLSurface;
typedef void* (*PFNEGLGETPROCADDRESS)(const char*);

#define EGL_NO_CONTEXT nullptr
#define EGL_FALSE 0
#define EGL_TRUE 1
#define EGL_BLUE_SIZE 0x3022
#define EGL_GREEN_SIZE 0x3023
#define EGL_RED_SIZE 0x3024
#define EGL_NONE 0x3038
#define EGL_VENDOR 0x3053
#define EGL_CONTEXT_CLIENT_VERSION 0x3098
#define EGL_DEVICE_EXT 0x322C
#define EGL_DRM_DEVICE_FILE_EXT 0x3233

// stuff from xf86drm.h
#define DRM_NODE_RENDER 2
#define DRM_NODE_MAX 3

typedef struct _drmDevice {
  char** nodes;
  int available_nodes;
  int bustype;
  union {
    void* pci;
    void* usb;
    void* platform;
    void* host1x;
  } businfo;
  union {
    void* pci;
    void* usb;
    void* platform;
    void* host1x;
  } deviceinfo;
} drmDevice, *drmDevicePtr;

// Open libGL and load needed symbols
#if defined(__OpenBSD__) || defined(__NetBSD__)
#  define LIBGL_FILENAME "libGL.so"
#  define LIBGLES_FILENAME "libGLESv2.so"
#  define LIBEGL_FILENAME "libEGL.so"
#  define LIBDRM_FILENAME "libdrm.so"
#else
#  define LIBGL_FILENAME "libGL.so.1"
#  define LIBGLES_FILENAME "libGLESv2.so.2"
#  define LIBEGL_FILENAME "libEGL.so.1"
#  define LIBDRM_FILENAME "libdrm.so.2"
#endif

#define EXIT_FAILURE_BUFFER_TOO_SMALL 2

namespace mozilla {
namespace widget {
// the read end of the pipe, which will be used by GfxInfo
extern int glxtest_pipe;
// the PID of the glxtest process, to pass to waitpid()
extern pid_t glxtest_pid;
}  // namespace widget
}  // namespace mozilla

// the write end of the pipe, which we're going to write to
static int write_end_of_the_pipe = -1;

// our buffer, size and used length
static char* glxtest_buf = nullptr;
static int glxtest_bufsize = 0;
static int glxtest_length = 0;

// C++ standard collides with C standard in that it doesn't allow casting void*
// to function pointer types. So the work-around is to convert first to size_t.
// http://www.trilithium.com/johan/2004/12/problem-with-dlsym/
template <typename func_ptr_type>
static func_ptr_type cast(void* ptr) {
  return reinterpret_cast<func_ptr_type>(reinterpret_cast<size_t>(ptr));
}

static void record_value(const char* format, ...) {
  // Don't add more if the buffer is full.
  if (glxtest_bufsize <= glxtest_length) {
    return;
  }

  // Append the new values to the buffer, not to exceed the remaining space.
  int remaining = glxtest_bufsize - glxtest_length;
  va_list args;
  va_start(args, format);
  int max_added =
      vsnprintf(glxtest_buf + glxtest_length, remaining, format, args);
  va_end(args);

  // snprintf returns how many char it could have added, not how many it added.
  // It is important to get this right since it will control how many chars we
  // will attempt to write to the pipe fd.
  if (max_added > remaining) {
    glxtest_length += remaining;
  } else {
    glxtest_length += max_added;
  }
}

static void record_error(const char* str) { record_value("ERROR\n%s\n", str); }

static void record_warning(const char* str) {
  record_value("WARNING\n%s\n", str);
}

static void record_flush() {
  mozilla::Unused << write(write_end_of_the_pipe, glxtest_buf, glxtest_length);
}

#ifdef MOZ_X11
static int x_error_handler(Display*, XErrorEvent* ev) {
  record_value(
      "ERROR\nX error, error_code=%d, "
      "request_code=%d, minor_code=%d\n",
      ev->error_code, ev->request_code, ev->minor_code);
  record_flush();
  _exit(EXIT_FAILURE);
  return 0;
}
#endif

// childgltest is declared inside extern "C" so that the name is not mangled.
// The name is used in build/valgrind/x86_64-pc-linux-gnu.sup to suppress
// memory leak errors because we run it inside a short lived fork and we don't
// care about leaking memory
extern "C" {

static void close_logging() {
  // we want to redirect to /dev/null stdout, stderr, and while we're at it,
  // any PR logging file descriptors. To that effect, we redirect all positive
  // file descriptors up to what open() returns here. In particular, 1 is stdout
  // and 2 is stderr.
  int fd = open("/dev/null", O_WRONLY);
  for (int i = 1; i < fd; i++) {
    dup2(fd, i);
  }
  close(fd);

  if (getenv("MOZ_AVOID_OPENGL_ALTOGETHER")) {
    const char* msg = "ERROR\nMOZ_AVOID_OPENGL_ALTOGETHER envvar set";
    mozilla::Unused << write(write_end_of_the_pipe, msg, strlen(msg));
    exit(EXIT_FAILURE);
  }
}

#define PCI_FILL_IDENT 0x0001
#define PCI_FILL_CLASS 0x0020
#define PCI_BASE_CLASS_DISPLAY 0x03

static void get_pci_status() {
  void* libpci = dlopen("libpci.so.3", RTLD_LAZY);
  if (!libpci) {
    libpci = dlopen("libpci.so", RTLD_LAZY);
  }
  if (!libpci) {
    record_warning("libpci missing");
    return;
  }

  typedef struct pci_dev {
    struct pci_dev* next;
    uint16_t domain_16;
    uint8_t bus, dev, func;
    unsigned int known_fields;
    uint16_t vendor_id, device_id;
    uint16_t device_class;
  } pci_dev;

  typedef struct pci_access {
    unsigned int method;
    int writeable;
    int buscentric;
    char* id_file_name;
    int free_id_name;
    int numeric_ids;
    unsigned int id_lookup_mode;
    int debugging;
    void* error;
    void* warning;
    void* debug;
    pci_dev* devices;
  } pci_access;

  typedef pci_access* (*PCIALLOC)(void);
  PCIALLOC pci_alloc = cast<PCIALLOC>(dlsym(libpci, "pci_alloc"));

  typedef void (*PCIINIT)(pci_access*);
  PCIINIT pci_init = cast<PCIINIT>(dlsym(libpci, "pci_init"));

  typedef void (*PCICLEANUP)(pci_access*);
  PCICLEANUP pci_cleanup = cast<PCICLEANUP>(dlsym(libpci, "pci_cleanup"));

  typedef void (*PCISCANBUS)(pci_access*);
  PCISCANBUS pci_scan_bus = cast<PCISCANBUS>(dlsym(libpci, "pci_scan_bus"));

  typedef void (*PCIFILLINFO)(pci_dev*, int);
  PCIFILLINFO pci_fill_info = cast<PCIFILLINFO>(dlsym(libpci, "pci_fill_info"));

  if (!pci_alloc || !pci_cleanup || !pci_scan_bus || !pci_fill_info) {
    dlclose(libpci);
    record_warning("libpci missing methods");
    return;
  }

  pci_access* pacc = pci_alloc();
  if (!pacc) {
    dlclose(libpci);
    record_warning("libpci alloc failed");
    return;
  }

  pci_init(pacc);
  pci_scan_bus(pacc);

  for (pci_dev* dev = pacc->devices; dev; dev = dev->next) {
    pci_fill_info(dev, PCI_FILL_IDENT | PCI_FILL_CLASS);
    if (dev->device_class >> 8 == PCI_BASE_CLASS_DISPLAY && dev->vendor_id &&
        dev->device_id) {
      record_value("PCI_VENDOR_ID\n0x%04x\nPCI_DEVICE_ID\n0x%04x\n",
                   dev->vendor_id, dev->device_id);
    }
  }

  pci_cleanup(pacc);
  dlclose(libpci);
}

#ifdef MOZ_WAYLAND
static bool device_has_name(const drmDevice* device, const char* name) {
  for (size_t i = 0; i < DRM_NODE_MAX; i++) {
    if (!(device->available_nodes & (1 << i))) {
      continue;
    }
    if (strcmp(device->nodes[i], name) == 0) {
      return true;
    }
  }
  return false;
}

static char* get_render_name(const char* name) {
  void* libdrm = dlopen(LIBDRM_FILENAME, RTLD_LAZY);
  if (!libdrm) {
    record_warning("Failed to open libdrm");
    return nullptr;
  }

  typedef int (*DRMGETDEVICES2)(uint32_t, drmDevicePtr*, int);
  DRMGETDEVICES2 drmGetDevices2 =
      cast<DRMGETDEVICES2>(dlsym(libdrm, "drmGetDevices2"));

  typedef void (*DRMFREEDEVICE)(drmDevicePtr*);
  DRMFREEDEVICE drmFreeDevice =
      cast<DRMFREEDEVICE>(dlsym(libdrm, "drmFreeDevice"));

  if (!drmGetDevices2 || !drmFreeDevice) {
    record_warning(
        "libdrm missing methods for drmGetDevices2 or drmFreeDevice");
    dlclose(libdrm);
    return nullptr;
  }

  uint32_t flags = 0;
  int devices_len = drmGetDevices2(flags, nullptr, 0);
  if (devices_len < 0) {
    record_warning("drmGetDevices2 failed");
    dlclose(libdrm);
    return nullptr;
  }
  drmDevice** devices = (drmDevice**)calloc(devices_len, sizeof(drmDevice*));
  if (!devices) {
    record_warning("Allocation error");
    dlclose(libdrm);
    return nullptr;
  }
  devices_len = drmGetDevices2(flags, devices, devices_len);
  if (devices_len < 0) {
    free(devices);
    record_warning("drmGetDevices2 failed");
    dlclose(libdrm);
    return nullptr;
  }

  const drmDevice* match = nullptr;
  for (int i = 0; i < devices_len; i++) {
    if (device_has_name(devices[i], name)) {
      match = devices[i];
      break;
    }
  }

  char* render_name = nullptr;
  if (!match) {
    record_warning("Cannot find DRM device");
  } else if (!(match->available_nodes & (1 << DRM_NODE_RENDER))) {
    record_warning("DRM device has no render node");
  } else {
    render_name = strdup(match->nodes[DRM_NODE_RENDER]);
  }

  for (int i = 0; i < devices_len; i++) {
    drmFreeDevice(&devices[i]);
  }
  free(devices);

  dlclose(libdrm);
  return render_name;
}
#endif

static void get_gles_status(EGLDisplay dpy,
                            PFNEGLGETPROCADDRESS eglGetProcAddress) {
  typedef EGLBoolean (*PFNEGLCHOOSECONFIGPROC)(
      EGLDisplay dpy, EGLint const* attrib_list, EGLConfig* configs,
      EGLint config_size, EGLint* num_config);
  PFNEGLCHOOSECONFIGPROC eglChooseConfig =
      cast<PFNEGLCHOOSECONFIGPROC>(eglGetProcAddress("eglChooseConfig"));

  typedef EGLContext (*PFNEGLCREATECONTEXTPROC)(
      EGLDisplay dpy, EGLConfig config, EGLContext share_context,
      EGLint const* attrib_list);
  PFNEGLCREATECONTEXTPROC eglCreateContext =
      cast<PFNEGLCREATECONTEXTPROC>(eglGetProcAddress("eglCreateContext"));

  typedef EGLSurface (*PFNEGLCREATEPBUFFERSURFACEPROC)(
      EGLDisplay dpy, EGLConfig config, EGLint const* attrib_list);
  PFNEGLCREATEPBUFFERSURFACEPROC eglCreatePbufferSurface =
      cast<PFNEGLCREATEPBUFFERSURFACEPROC>(
          eglGetProcAddress("eglCreatePbufferSurface"));

  typedef EGLBoolean (*PFNEGLMAKECURRENTPROC)(
      EGLDisplay dpy, EGLSurface draw, EGLSurface read, EGLContext context);
  PFNEGLMAKECURRENTPROC eglMakeCurrent =
      cast<PFNEGLMAKECURRENTPROC>(eglGetProcAddress("eglMakeCurrent"));

  typedef const char* (*PFNEGLQUERYDEVICESTRINGEXTPROC)(EGLDeviceEXT device,
                                                        EGLint name);
  PFNEGLQUERYDEVICESTRINGEXTPROC eglQueryDeviceStringEXT =
      cast<PFNEGLQUERYDEVICESTRINGEXTPROC>(
          eglGetProcAddress("eglQueryDeviceStringEXT"));

  typedef EGLBoolean (*PFNEGLQUERYDISPLAYATTRIBEXTPROC)(
      EGLDisplay dpy, EGLint name, EGLAttrib * value);
  PFNEGLQUERYDISPLAYATTRIBEXTPROC eglQueryDisplayAttribEXT =
      cast<PFNEGLQUERYDISPLAYATTRIBEXTPROC>(
          eglGetProcAddress("eglQueryDisplayAttribEXT"));

  if (!eglChooseConfig || !eglCreateContext || !eglCreatePbufferSurface ||
      !eglMakeCurrent) {
    record_error("libEGL missing methods for GLES test");
    return;
  }

  typedef GLubyte* (*PFNGLGETSTRING)(GLenum);
  PFNGLGETSTRING glGetString =
      cast<PFNGLGETSTRING>(eglGetProcAddress("glGetString"));

  // Implementations disagree about whether eglGetProcAddress or dlsym
  // should be used for getting functions from the actual API, see
  // https://github.com/anholt/libepoxy/commit/14f24485e33816139398d1bd170d617703473738
  void* libgl = nullptr;
  if (!glGetString) {
    libgl = dlopen(LIBGL_FILENAME, RTLD_LAZY);
    if (!libgl) {
      libgl = dlopen(LIBGLES_FILENAME, RTLD_LAZY);
      if (!libgl) {
        record_error("Unable to load " LIBGL_FILENAME " or " LIBGLES_FILENAME);
        return;
      }
    }

    glGetString = cast<PFNGLGETSTRING>(dlsym(libgl, "glGetString"));
    if (!glGetString) {
      dlclose(libgl);
      record_error("libGL or libGLESv2 glGetString missing");
      return;
    }
  }

  EGLint config_attrs[] = {EGL_RED_SIZE,  8, EGL_GREEN_SIZE, 8,
                           EGL_BLUE_SIZE, 8, EGL_NONE};
  EGLConfig config;
  EGLint num_config;
  eglChooseConfig(dpy, config_attrs, &config, 1, &num_config);
  EGLint ctx_attrs[] = {EGL_CONTEXT_CLIENT_VERSION, 3, EGL_NONE};
  EGLContext ectx = eglCreateContext(dpy, config, EGL_NO_CONTEXT, ctx_attrs);
  EGLSurface pbuf = eglCreatePbufferSurface(dpy, config, nullptr);
  eglMakeCurrent(dpy, pbuf, pbuf, ectx);

  const GLubyte* versionString = glGetString(GL_VERSION);
  const GLubyte* vendorString = glGetString(GL_VENDOR);
  const GLubyte* rendererString = glGetString(GL_RENDERER);

  if (versionString && vendorString && rendererString) {
    record_value("VENDOR\n%s\nRENDERER\n%s\nVERSION\n%s\nTFP\nTRUE\n",
                 vendorString, rendererString, versionString);
  } else {
    record_error("libGLESv2 glGetString returned null");
  }

  if (eglQueryDeviceStringEXT) {
    EGLDeviceEXT device = nullptr;

    if (eglQueryDisplayAttribEXT(dpy, EGL_DEVICE_EXT, (EGLAttrib*)&device) ==
        EGL_TRUE) {
      const char* deviceString =
          eglQueryDeviceStringEXT(device, EGL_DRM_DEVICE_FILE_EXT);
      if (deviceString) {
        record_value("MESA_ACCELERATED\nTRUE\n");

#ifdef MOZ_WAYLAND
        char* renderDeviceName = get_render_name(deviceString);
        if (renderDeviceName) {
          record_value("DRM_RENDERDEVICE\n%s\n", renderDeviceName);
        } else {
          record_warning("Can't find render node name for DRM device");
        }
#endif
      }
    }
  }

  if (libgl) {
    dlclose(libgl);
  }
}

static void get_egl_status(EGLNativeDisplayType native_dpy, bool gles_test) {
  void* libegl = dlopen(LIBEGL_FILENAME, RTLD_LAZY);
  if (!libegl) {
    record_warning("libEGL missing");
    return;
  }

  PFNEGLGETPROCADDRESS eglGetProcAddress =
      cast<PFNEGLGETPROCADDRESS>(dlsym(libegl, "eglGetProcAddress"));

  if (!eglGetProcAddress) {
    dlclose(libegl);
    record_error("no eglGetProcAddress");
    return;
  }

  typedef EGLDisplay (*PFNEGLGETDISPLAYPROC)(void* native_display);
  PFNEGLGETDISPLAYPROC eglGetDisplay =
      cast<PFNEGLGETDISPLAYPROC>(eglGetProcAddress("eglGetDisplay"));

  typedef EGLBoolean (*PFNEGLINITIALIZEPROC)(EGLDisplay dpy, EGLint * major,
                                             EGLint * minor);
  PFNEGLINITIALIZEPROC eglInitialize =
      cast<PFNEGLINITIALIZEPROC>(eglGetProcAddress("eglInitialize"));

  typedef EGLBoolean (*PFNEGLTERMINATEPROC)(EGLDisplay dpy);
  PFNEGLTERMINATEPROC eglTerminate =
      cast<PFNEGLTERMINATEPROC>(eglGetProcAddress("eglTerminate"));

  if (!eglGetDisplay || !eglInitialize || !eglTerminate) {
    dlclose(libegl);
    record_error("libEGL missing methods");
    return;
  }

  EGLDisplay dpy = eglGetDisplay(native_dpy);
  if (!dpy) {
    dlclose(libegl);
    record_warning("libEGL no display");
    return;
  }

  EGLint major, minor;
  if (!eglInitialize(dpy, &major, &minor)) {
    dlclose(libegl);
    record_warning("libEGL initialize failed");
    return;
  }

  if (gles_test) {
    get_gles_status(dpy, eglGetProcAddress);
  }

  typedef const char* (*PFNEGLGETDISPLAYDRIVERNAMEPROC)(EGLDisplay dpy);
  PFNEGLGETDISPLAYDRIVERNAMEPROC eglGetDisplayDriverName =
      cast<PFNEGLGETDISPLAYDRIVERNAMEPROC>(
          eglGetProcAddress("eglGetDisplayDriverName"));
  if (eglGetDisplayDriverName) {
    const char* driDriver = eglGetDisplayDriverName(dpy);
    if (driDriver) {
      record_value("DRI_DRIVER\n%s\n", driDriver);
    }
  }

  eglTerminate(dpy);
  dlclose(libegl);
}

#ifdef MOZ_X11
static void get_x11_screen_info(Display* dpy) {
  int screenCount = ScreenCount(dpy);
  int defaultScreen = DefaultScreen(dpy);
  if (screenCount != 0) {
    record_value("SCREEN_INFO\n");
    for (int idx = 0; idx < screenCount; idx++) {
      Screen* scrn = ScreenOfDisplay(dpy, idx);
      int current_height = scrn->height;
      int current_width = scrn->width;

      record_value("%dx%d:%d%s", current_width, current_height,
                   idx == defaultScreen ? 1 : 0,
                   idx == screenCount - 1 ? ";\n" : ";");
    }
  }
}

static void get_glx_status(int* gotGlxInfo, int* gotDriDriver) {
  void* libgl = dlopen(LIBGL_FILENAME, RTLD_LAZY);
  if (!libgl) {
    record_error(LIBGL_FILENAME " missing");
    return;
  }

  typedef void* (*PFNGLXGETPROCADDRESS)(const char*);
  PFNGLXGETPROCADDRESS glXGetProcAddress =
      cast<PFNGLXGETPROCADDRESS>(dlsym(libgl, "glXGetProcAddress"));

  if (!glXGetProcAddress) {
    record_error("no glXGetProcAddress");
    return;
  }

  typedef GLXFBConfig* (*PFNGLXQUERYEXTENSION)(Display*, int*, int*);
  PFNGLXQUERYEXTENSION glXQueryExtension =
      cast<PFNGLXQUERYEXTENSION>(glXGetProcAddress("glXQueryExtension"));

  typedef GLXFBConfig* (*PFNGLXQUERYVERSION)(Display*, int*, int*);
  PFNGLXQUERYVERSION glXQueryVersion =
      cast<PFNGLXQUERYVERSION>(dlsym(libgl, "glXQueryVersion"));

  typedef XVisualInfo* (*PFNGLXCHOOSEVISUAL)(Display*, int, int*);
  PFNGLXCHOOSEVISUAL glXChooseVisual =
      cast<PFNGLXCHOOSEVISUAL>(glXGetProcAddress("glXChooseVisual"));

  typedef GLXContext (*PFNGLXCREATECONTEXT)(Display*, XVisualInfo*, GLXContext,
                                            Bool);
  PFNGLXCREATECONTEXT glXCreateContext =
      cast<PFNGLXCREATECONTEXT>(glXGetProcAddress("glXCreateContext"));

  typedef Bool (*PFNGLXMAKECURRENT)(Display*, GLXDrawable, GLXContext);
  PFNGLXMAKECURRENT glXMakeCurrent =
      cast<PFNGLXMAKECURRENT>(glXGetProcAddress("glXMakeCurrent"));

  typedef void (*PFNGLXDESTROYCONTEXT)(Display*, GLXContext);
  PFNGLXDESTROYCONTEXT glXDestroyContext =
      cast<PFNGLXDESTROYCONTEXT>(glXGetProcAddress("glXDestroyContext"));

  typedef GLubyte* (*PFNGLGETSTRING)(GLenum);
  PFNGLGETSTRING glGetString =
      cast<PFNGLGETSTRING>(glXGetProcAddress("glGetString"));

  if (!glXQueryExtension || !glXQueryVersion || !glXChooseVisual ||
      !glXCreateContext || !glXMakeCurrent || !glXDestroyContext ||
      !glGetString) {
    record_error(LIBGL_FILENAME " missing methods");
    return;
  }

  ///// Open a connection to the X server /////
  Display* dpy = XOpenDisplay(nullptr);
  if (!dpy) {
    record_error("Unable to open a connection to the X server");
    return;
  }

  ///// Check that the GLX extension is present /////
  if (!glXQueryExtension(dpy, nullptr, nullptr)) {
    record_error("GLX extension missing");
    return;
  }

  XSetErrorHandler(x_error_handler);

  ///// Get a visual /////
  int attribs[] = {GLX_RGBA, GLX_RED_SIZE,  1, GLX_GREEN_SIZE,
                   1,        GLX_BLUE_SIZE, 1, None};
  XVisualInfo* vInfo = glXChooseVisual(dpy, DefaultScreen(dpy), attribs);
  if (!vInfo) {
    record_error("No visuals found");
    return;
  }

  // using a X11 Window instead of a GLXPixmap does not crash
  // fglrx in indirect rendering. bug 680644
  Window window;
  XSetWindowAttributes swa;
  swa.colormap = XCreateColormap(dpy, RootWindow(dpy, vInfo->screen),
                                 vInfo->visual, AllocNone);

  swa.border_pixel = 0;
  window = XCreateWindow(dpy, RootWindow(dpy, vInfo->screen), 0, 0, 16, 16, 0,
                         vInfo->depth, InputOutput, vInfo->visual,
                         CWBorderPixel | CWColormap, &swa);

  ///// Get a GL context and make it current //////
  GLXContext context = glXCreateContext(dpy, vInfo, nullptr, True);
  glXMakeCurrent(dpy, window, context);

  ///// Look for this symbol to determine texture_from_pixmap support /////
  void* glXBindTexImageEXT = glXGetProcAddress("glXBindTexImageEXT");

  ///// Get GL vendor/renderer/versions strings /////
  const GLubyte* versionString = glGetString(GL_VERSION);
  const GLubyte* vendorString = glGetString(GL_VENDOR);
  const GLubyte* rendererString = glGetString(GL_RENDERER);

  if (versionString && vendorString && rendererString) {
    record_value("VENDOR\n%s\nRENDERER\n%s\nVERSION\n%s\nTFP\n%s\n",
                 vendorString, rendererString, versionString,
                 glXBindTexImageEXT ? "TRUE" : "FALSE");
    *gotGlxInfo = 1;
  } else {
    record_error("glGetString returned null");
  }

  // If GLX_MESA_query_renderer is available, populate additional data.
  typedef Bool (*PFNGLXQUERYCURRENTRENDERERINTEGERMESAPROC)(
      int attribute, unsigned int* value);
  PFNGLXQUERYCURRENTRENDERERINTEGERMESAPROC
  glXQueryCurrentRendererIntegerMESAProc =
      cast<PFNGLXQUERYCURRENTRENDERERINTEGERMESAPROC>(
          glXGetProcAddress("glXQueryCurrentRendererIntegerMESA"));
  if (glXQueryCurrentRendererIntegerMESAProc) {
    unsigned int vendorId, deviceId, accelerated, videoMemoryMB;
    glXQueryCurrentRendererIntegerMESAProc(GLX_RENDERER_VENDOR_ID_MESA,
                                           &vendorId);
    glXQueryCurrentRendererIntegerMESAProc(GLX_RENDERER_DEVICE_ID_MESA,
                                           &deviceId);
    glXQueryCurrentRendererIntegerMESAProc(GLX_RENDERER_ACCELERATED_MESA,
                                           &accelerated);
    glXQueryCurrentRendererIntegerMESAProc(GLX_RENDERER_VIDEO_MEMORY_MESA,
                                           &videoMemoryMB);

    // Truncate IDs to 4 digits- that's all PCI IDs are.
    vendorId &= 0xFFFF;
    deviceId &= 0xFFFF;

    record_value(
        "MESA_VENDOR_ID\n0x%04x\n"
        "MESA_DEVICE_ID\n0x%04x\n"
        "MESA_ACCELERATED\n%s\n"
        "MESA_VRAM\n%dMB\n",
        vendorId, deviceId, accelerated ? "TRUE" : "FALSE", videoMemoryMB);
  }

  // From Mesa's GL/internal/dri_interface.h, to be used by DRI clients.
  typedef const char* (*PFNGLXGETSCREENDRIVERPROC)(Display * dpy, int scrNum);
  PFNGLXGETSCREENDRIVERPROC glXGetScreenDriverProc =
      cast<PFNGLXGETSCREENDRIVERPROC>(glXGetProcAddress("glXGetScreenDriver"));
  if (glXGetScreenDriverProc) {
    const char* driDriver = glXGetScreenDriverProc(dpy, DefaultScreen(dpy));
    if (driDriver) {
      *gotDriDriver = 1;
      record_value("DRI_DRIVER\n%s\n", driDriver);
    }
  }

  // Get monitor information
  get_x11_screen_info(dpy);

  ///// Clean up. Indeed, the parent process might fail to kill us (e.g. if it
  ///// doesn't need to check GL info) so we might be staying alive for longer
  ///// than expected, so it's important to consume as little memory as
  ///// possible. Also we want to check that we're able to do that too without
  ///// generating X errors.
  glXMakeCurrent(dpy, None,
                 nullptr);  // must release the GL context before destroying it
  glXDestroyContext(dpy, context);
  XDestroyWindow(dpy, window);
  XFreeColormap(dpy, swa.colormap);

#  ifdef NS_FREE_PERMANENT_DATA  // conditionally defined in nscore.h, don't
                                 // forget to #include it above
  XCloseDisplay(dpy);
#  else
  // This XSync call wanted to be instead:
  //   XCloseDisplay(dpy);
  // but this can cause 1-minute stalls on certain setups using Nouveau, see bug
  // 973192
  XSync(dpy, False);
#  endif

  dlclose(libgl);
}

static bool x11_egltest() {
  get_egl_status(nullptr, true);

  Display* dpy = XOpenDisplay(nullptr);
  if (!dpy) {
    return false;
  }
  XSetErrorHandler(x_error_handler);

  get_x11_screen_info(dpy);

  XCloseDisplay(dpy);
  return true;
}

static void glxtest() {
  int gotGlxInfo = 0;
  int gotDriDriver = 0;

  get_glx_status(&gotGlxInfo, &gotDriDriver);
  if (!gotGlxInfo) {
    get_egl_status(nullptr, true);
  } else if (!gotDriDriver) {
    // If we failed to get the driver name from X, try via
    // EGL_MESA_query_driver. We are probably using Wayland.
    get_egl_status(nullptr, false);
  }
}
#endif

#ifdef MOZ_WAYLAND
typedef void (*print_info_t)(void* info);
typedef void (*destroy_info_t)(void* info);

struct global_info {
  struct wl_list link;

  uint32_t id;
  uint32_t version;
  char* interface;

  print_info_t print;
  destroy_info_t destroy;
};

struct output_info {
  struct global_info global;
  struct wl_list global_link;

  struct wl_output* output;

  int32_t version;

  int32_t scale;
};

struct xdg_output_v1_info {
  struct wl_list link;

  struct zxdg_output_v1* xdg_output;
  struct output_info* output;

  struct {
    int32_t width, height;
  } logical;

  char *name, *description;
};

struct xdg_output_manager_v1_info {
  struct global_info global;
  struct zxdg_output_manager_v1* manager;
  struct weston_info* info;

  struct wl_list outputs;
};

struct weston_info {
  struct wl_display* display;
  struct wl_registry* registry;

  struct wl_list infos;
  bool roundtrip_needed;

  struct wl_list outputs;
  struct xdg_output_manager_v1_info* xdg_output_manager_v1_info;
};

static void init_global_info(struct weston_info* info,
                             struct global_info* global, uint32_t id,
                             const char* interface, uint32_t version) {
  global->id = id;
  global->version = version;
  global->interface = strdup(interface);

  wl_list_insert(info->infos.prev, &global->link);
}

static void print_output_info(void* data) {}

static void destroy_xdg_output_v1_info(struct xdg_output_v1_info* info) {
  wl_list_remove(&info->link);
  zxdg_output_v1_destroy(info->xdg_output);
  free(info->name);
  free(info->description);
  free(info);
}

static int cmpOutputIds(const void* a, const void* b) {
  return (((struct xdg_output_v1_info*)a)->output->global.id -
          ((struct xdg_output_v1_info*)b)->output->global.id);
}

static void print_xdg_output_manager_v1_info(void* data) {
  struct xdg_output_manager_v1_info* info =
      (struct xdg_output_manager_v1_info*)data;
  struct xdg_output_v1_info* output;

  int screen_count = wl_list_length(&info->outputs);
  if (screen_count > 0) {
    struct xdg_output_v1_info* infos = (struct xdg_output_v1_info*)malloc(
        screen_count * sizeof(xdg_output_v1_info));

    int pos = 0;
    wl_list_for_each(output, &info->outputs, link) {
      infos[pos] = *output;
      pos++;
    }

    if (screen_count > 1) {
      qsort(infos, screen_count, sizeof(struct xdg_output_v1_info),
            cmpOutputIds);
    }

    record_value("SCREEN_INFO\n");
    for (int i = 0; i < screen_count; i++) {
      record_value("%dx%d:0;", infos[i].logical.width, infos[i].logical.height);
    }
    record_value("\n");

    free(infos);
  }
}

static void destroy_xdg_output_manager_v1_info(void* data) {
  struct xdg_output_manager_v1_info* info =
      (struct xdg_output_manager_v1_info*)data;
  struct xdg_output_v1_info *output, *tmp;

  zxdg_output_manager_v1_destroy(info->manager);

  wl_list_for_each_safe(output, tmp, &info->outputs, link)
      destroy_xdg_output_v1_info(output);
}

static void handle_xdg_output_v1_logical_position(void* data,
                                                  struct zxdg_output_v1* output,
                                                  int32_t x, int32_t y) {}

static void handle_xdg_output_v1_logical_size(void* data,
                                              struct zxdg_output_v1* output,
                                              int32_t width, int32_t height) {
  struct xdg_output_v1_info* xdg_output = (struct xdg_output_v1_info*)data;
  xdg_output->logical.width = width;
  xdg_output->logical.height = height;
}

static void handle_xdg_output_v1_done(void* data,
                                      struct zxdg_output_v1* output) {}

static void handle_xdg_output_v1_name(void* data, struct zxdg_output_v1* output,
                                      const char* name) {
  struct xdg_output_v1_info* xdg_output = (struct xdg_output_v1_info*)data;
  xdg_output->name = strdup(name);
}

static void handle_xdg_output_v1_description(void* data,
                                             struct zxdg_output_v1* output,
                                             const char* description) {
  struct xdg_output_v1_info* xdg_output = (struct xdg_output_v1_info*)data;
  xdg_output->description = strdup(description);
}

static const struct zxdg_output_v1_listener xdg_output_v1_listener = {
    .logical_position = handle_xdg_output_v1_logical_position,
    .logical_size = handle_xdg_output_v1_logical_size,
    .done = handle_xdg_output_v1_done,
    .name = handle_xdg_output_v1_name,
    .description = handle_xdg_output_v1_description,
};

static void add_xdg_output_v1_info(
    struct xdg_output_manager_v1_info* manager_info,
    struct output_info* output) {
  struct xdg_output_v1_info* xdg_output =
      (struct xdg_output_v1_info*)malloc(sizeof *xdg_output);

  wl_list_insert(&manager_info->outputs, &xdg_output->link);
  xdg_output->xdg_output = zxdg_output_manager_v1_get_xdg_output(
      manager_info->manager, output->output);
  zxdg_output_v1_add_listener(xdg_output->xdg_output, &xdg_output_v1_listener,
                              xdg_output);

  xdg_output->output = output;

  manager_info->info->roundtrip_needed = true;
}

static void add_xdg_output_manager_v1_info(struct weston_info* info,
                                           uint32_t id, uint32_t version) {
  struct output_info* output;
  struct xdg_output_manager_v1_info* manager =
      (struct xdg_output_manager_v1_info*)malloc(sizeof *manager);

  wl_list_init(&manager->outputs);
  manager->info = info;

  init_global_info(info, &manager->global, id,
                   zxdg_output_manager_v1_interface.name, version);
  manager->global.print = print_xdg_output_manager_v1_info;
  manager->global.destroy = destroy_xdg_output_manager_v1_info;

  manager->manager = (struct zxdg_output_manager_v1*)wl_registry_bind(
      info->registry, id, &zxdg_output_manager_v1_interface,
      version > 2 ? 2 : version);

  wl_list_for_each(output, &info->outputs, global_link)
      add_xdg_output_v1_info(manager, output);

  info->xdg_output_manager_v1_info = manager;
}

static void output_handle_geometry(void* data, struct wl_output* wl_output,
                                   int32_t x, int32_t y, int32_t physical_width,
                                   int32_t physical_height, int32_t subpixel,
                                   const char* make, const char* model,
                                   int32_t output_transform) {}

static void output_handle_mode(void* data, struct wl_output* wl_output,
                               uint32_t flags, int32_t width, int32_t height,
                               int32_t refresh) {}

static void output_handle_done(void* data, struct wl_output* wl_output) {}

static void output_handle_scale(void* data, struct wl_output* wl_output,
                                int32_t scale) {
  struct output_info* output = (struct output_info*)data;

  output->scale = scale;
}

static const struct wl_output_listener output_listener = {
    output_handle_geometry,
    output_handle_mode,
    output_handle_done,
    output_handle_scale,
};

static void destroy_output_info(void* data) {
  struct output_info* output = (struct output_info*)data;

  wl_output_destroy(output->output);
}

static void add_output_info(struct weston_info* info, uint32_t id,
                            uint32_t version) {
  struct output_info* output = (struct output_info*)malloc(sizeof *output);

  init_global_info(info, &output->global, id, "wl_output", version);
  output->global.print = print_output_info;
  output->global.destroy = destroy_output_info;

  output->version = MIN(version, 2);
  output->scale = 1;

  output->output = (struct wl_output*)wl_registry_bind(
      info->registry, id, &wl_output_interface, output->version);
  wl_output_add_listener(output->output, &output_listener, output);

  info->roundtrip_needed = true;
  wl_list_insert(&info->outputs, &output->global_link);

  if (info->xdg_output_manager_v1_info) {
    add_xdg_output_v1_info(info->xdg_output_manager_v1_info, output);
  }
}

static void global_handler(void* data, struct wl_registry* registry,
                           uint32_t id, const char* interface,
                           uint32_t version) {
  struct weston_info* info = (struct weston_info*)data;

  if (!strcmp(interface, "wl_output")) {
    add_output_info(info, id, version);
  } else if (!strcmp(interface, zxdg_output_manager_v1_interface.name)) {
    add_xdg_output_manager_v1_info(info, id, version);
  }
}

static void global_remove_handler(void* data, struct wl_registry* registry,
                                  uint32_t name) {}

static const struct wl_registry_listener registry_listener = {
    global_handler, global_remove_handler};

static void print_infos(struct wl_list* infos) {
  struct global_info* info;

  wl_list_for_each(info, infos, link) { info->print(info); }
}

static void destroy_info(void* data) {
  struct global_info* global = (struct global_info*)data;

  global->destroy(data);
  wl_list_remove(&global->link);
  free(global->interface);
  free(data);
}

static void destroy_infos(struct wl_list* infos) {
  struct global_info *info, *tmp;
  wl_list_for_each_safe(info, tmp, infos, link) { destroy_info(info); }
}

static void get_wayland_screen_info(struct wl_display* dpy) {
  struct weston_info info = {0};
  info.display = dpy;

  info.xdg_output_manager_v1_info = NULL;
  wl_list_init(&info.infos);
  wl_list_init(&info.outputs);

  info.registry = wl_display_get_registry(info.display);
  wl_registry_add_listener(info.registry, &registry_listener, &info);

  do {
    info.roundtrip_needed = false;
    wl_display_roundtrip(info.display);
  } while (info.roundtrip_needed);

  print_infos(&info.infos);
  destroy_infos(&info.infos);

  wl_registry_destroy(info.registry);
}

static bool wayland_egltest() {
  // NOTE: returns false to fall back to X11 when the Wayland socket doesn't
  // exist but fails with record_error if something actually went wrong
  struct wl_display* dpy = wl_display_connect(nullptr);
  if (!dpy) {
    return false;
  }

  get_egl_status((EGLNativeDisplayType)dpy, true);
  get_wayland_screen_info(dpy);

  wl_display_disconnect(dpy);
  return true;
}
#endif

int childgltest() {
  enum { bufsize = 2048 };
  char buf[bufsize];

  // We save it as a global so that the X error handler can flush the buffer
  // before early exiting.
  glxtest_buf = buf;
  glxtest_bufsize = bufsize;

  // Get a list of all GPUs from the PCI bus.
  get_pci_status();

  bool result = false;
#ifdef MOZ_WAYLAND
  if (!IsWaylandDisabled()) {
    result = wayland_egltest();
  }
#endif
#ifdef MOZ_X11
  // TODO: --display command line argument is not properly handled
  if (!result && IsX11EGLEnabled()) {
    result = x11_egltest();
  }
  if (!result) {
    glxtest();
  }
#endif

  // Finally write buffered data to the pipe.
  record_flush();

  // If we completely filled the buffer, we need to tell the parent.
  if (glxtest_length >= glxtest_bufsize) {
    return EXIT_FAILURE_BUFFER_TOO_SMALL;
  }

  return EXIT_SUCCESS;
}

}  // extern "C"

/** \returns true in the child glxtest process, false in the parent process */
bool fire_glxtest_process() {
  int pfd[2];
  if (pipe(pfd) == -1) {
    perror("pipe");
    return false;
  }
  pid_t pid = fork();
  if (pid < 0) {
    perror("fork");
    close(pfd[0]);
    close(pfd[1]);
    return false;
  }
  // The child exits early to avoid running the full shutdown sequence and avoid
  // conflicting with threads we have already spawned (like the profiler).
  if (pid == 0) {
    close(pfd[0]);
    write_end_of_the_pipe = pfd[1];
    close_logging();
    int rv = childgltest();
    close(pfd[1]);
    _exit(rv);
  }

  close(pfd[1]);
  mozilla::widget::glxtest_pipe = pfd[0];
  mozilla::widget::glxtest_pid = pid;
  return false;
}