toolkit/xre/glxtest.cpp

   1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  * vim: sw=2 ts=8 et :
   3  */
   4 /* This Source Code Form is subject to the terms of the Mozilla Public
   5  * License, v. 2.0. If a copy of the MPL was not distributed with this
   6  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   7
   8
   9 //////////////////////////////////////////////////////////////////////////////
  10 //
  11 // Explanation: See bug 639842. Safely getting GL driver info on X11 is hard, because the only way to do
  12 // that is to create a GL context and call glGetString(), but with bad drivers,
  13 // just creating a GL context may crash.
  14 //
  15 // This file implements the idea to do that in a separate process.
  16 //
  17 // The only non-static function here is fire_glxtest_process(). It creates a pipe, publishes its 'read' end as the
  18 // mozilla::widget::glxtest_pipe global variable, forks, and runs that GLX probe in the child process,
  19 // which runs the glxtest() static function. This creates a X connection, a GLX context, calls glGetString, and writes that
  20 // to the 'write' end of the pipe.
  21
  22 #include <cstdio>
  23 #include <cstdlib>
  24 #include <unistd.h>
  25 #include <dlfcn.h>
  26 #include "nscore.h"
  27 #include <fcntl.h>
  28 #include "stdint.h"
  29
  30 #ifdef __SUNPRO_CC
  31 #include <stdio.h>
  32 #endif
  33
  34 #include "X11/Xlib.h"
  35 #include "X11/Xutil.h"
  36
  37 // stuff from glx.h
  38 typedef struct __GLXcontextRec *GLXContext;
  39 typedef XID GLXPixmap;
  40 typedef XID GLXDrawable;
  41 /* GLX 1.3 and later */
  42 typedef struct __GLXFBConfigRec *GLXFBConfig;
  43 typedef XID GLXFBConfigID;
  44 typedef XID GLXContextID;
  45 typedef XID GLXWindow;
  46 typedef XID GLXPbuffer;
  47 #define GLX_RGBA        4
  48 #define GLX_RED_SIZE    8
  49 #define GLX_GREEN_SIZE  9
  50 #define GLX_BLUE_SIZE   10
  51
  52 // stuff from gl.h
  53 typedef uint8_t GLubyte;
  54 typedef uint32_t GLenum;
  55 #define GL_VENDOR       0x1F00
  56 #define GL_RENDERER     0x1F01
  57 #define GL_VERSION      0x1F02
  58
  59 namespace mozilla {
  60 namespace widget {
  61 // the read end of the pipe, which will be used by GfxInfo
  62 extern int glxtest_pipe;
  63 // the PID of the glxtest process, to pass to waitpid()
  64 extern pid_t glxtest_pid;
  65 }
  66 }
  67
  68 // the write end of the pipe, which we're going to write to
  69 static int write_end_of_the_pipe = -1;
  70
  71 // C++ standard collides with C standard in that it doesn't allow casting void* to function pointer types.
  72 // So the work-around is to convert first to size_t.
  73 // http://www.trilithium.com/johan/2004/12/problem-with-dlsym/
  74 template<typename func_ptr_type>
  75 static func_ptr_type cast(void *ptr)
  76 {
  77   return reinterpret_cast<func_ptr_type>(
  78            reinterpret_cast<size_t>(ptr)
  79          );
  80 }
  81
  82 static void fatal_error(const char *str)
  83 {
  84   write(write_end_of_the_pipe, str, strlen(str));
  85   write(write_end_of_the_pipe, "\n", 1);
  86   exit(EXIT_FAILURE);
  87 }
  88
  89 static int
  90 x_error_handler(Display *, XErrorEvent *ev)
  91 {
  92   enum { bufsize = 1024 };
  93   char buf[bufsize];
  94   int length = snprintf(buf, bufsize,
  95                         "X error occurred in GLX probe, error_code=%d, request_code=%d, minor_code=%d\n",
  96                         ev->error_code,
  97                         ev->request_code,
  98                         ev->minor_code);
  99   write(write_end_of_the_pipe, buf, length);
 100   exit(EXIT_FAILURE);
 101   return 0;
 102 }
 103
 104 static void glxtest()
 105 {
 106   // we want to redirect to /dev/null stdout, stderr, and while we're at it,
 107   // any PR logging file descriptors. To that effect, we redirect all positive
 108   // file descriptors up to what open() returns here. In particular, 1 is stdout and 2 is stderr.
 109   int fd = open("/dev/null", O_WRONLY);
 110   for (int i = 1; i < fd; i++)
 111     dup2(fd, i);
 112   close(fd);
 113
 114   if (getenv("MOZ_AVOID_OPENGL_ALTOGETHER"))
 115     fatal_error("The MOZ_AVOID_OPENGL_ALTOGETHER environment variable is defined");
 116
 117   ///// Open libGL and load needed symbols /////
 118 #ifdef __OpenBSD__
 119   #define LIBGL_FILENAME "libGL.so"
 120 #else
 121   #define LIBGL_FILENAME "libGL.so.1"
 122 #endif
 123   void *libgl = dlopen(LIBGL_FILENAME, RTLD_LAZY);
 124   if (!libgl)
 125     fatal_error("Unable to load " LIBGL_FILENAME);
 126
 127   typedef void* (* PFNGLXGETPROCADDRESS) (const char *);
 128   PFNGLXGETPROCADDRESS glXGetProcAddress = cast<PFNGLXGETPROCADDRESS>(dlsym(libgl, "glXGetProcAddress"));
 129
 130   if (!glXGetProcAddress)
 131     fatal_error("Unable to find glXGetProcAddress in " LIBGL_FILENAME);
 132
 133   typedef GLXFBConfig* (* PFNGLXQUERYEXTENSION) (Display *, int *, int *);
 134   PFNGLXQUERYEXTENSION glXQueryExtension = cast<PFNGLXQUERYEXTENSION>(glXGetProcAddress("glXQueryExtension"));
 135
 136   typedef GLXFBConfig* (* PFNGLXQUERYVERSION) (Display *, int *, int *);
 137   PFNGLXQUERYVERSION glXQueryVersion = cast<PFNGLXQUERYVERSION>(dlsym(libgl, "glXQueryVersion"));
 138
 139   typedef XVisualInfo* (* PFNGLXCHOOSEVISUAL) (Display *, int, int *);
 140   PFNGLXCHOOSEVISUAL glXChooseVisual = cast<PFNGLXCHOOSEVISUAL>(glXGetProcAddress("glXChooseVisual"));
 141
 142   typedef GLXContext (* PFNGLXCREATECONTEXT) (Display *, XVisualInfo *, GLXContext, Bool);
 143   PFNGLXCREATECONTEXT glXCreateContext = cast<PFNGLXCREATECONTEXT>(glXGetProcAddress("glXCreateContext"));
 144
 145   typedef Bool (* PFNGLXMAKECURRENT) (Display*, GLXDrawable, GLXContext);
 146   PFNGLXMAKECURRENT glXMakeCurrent = cast<PFNGLXMAKECURRENT>(glXGetProcAddress("glXMakeCurrent"));
 147
 148   typedef void (* PFNGLXDESTROYCONTEXT) (Display*, GLXContext);
 149   PFNGLXDESTROYCONTEXT glXDestroyContext = cast<PFNGLXDESTROYCONTEXT>(glXGetProcAddress("glXDestroyContext"));
 150
 151   typedef GLubyte* (* PFNGLGETSTRING) (GLenum);
 152   PFNGLGETSTRING glGetString = cast<PFNGLGETSTRING>(glXGetProcAddress("glGetString"));
 153
 154   if (!glXQueryExtension ||
 155       !glXQueryVersion ||
 156       !glXChooseVisual ||
 157       !glXCreateContext ||
 158       !glXMakeCurrent ||
 159       !glXDestroyContext ||
 160       !glGetString)
 161   {
 162     fatal_error("glXGetProcAddress couldn't find required functions");
 163   }
 164   ///// Open a connection to the X server /////
 165   Display *dpy = XOpenDisplay(nullptr);
 166   if (!dpy)
 167     fatal_error("Unable to open a connection to the X server");
 168
 169   ///// Check that the GLX extension is present /////
 170   if (!glXQueryExtension(dpy, nullptr, nullptr))
 171     fatal_error("GLX extension missing");
 172
 173   XSetErrorHandler(x_error_handler);
 174
 175   ///// Get a visual /////
 176    int attribs[] = {
 177       GLX_RGBA,
 178       GLX_RED_SIZE, 1,
 179       GLX_GREEN_SIZE, 1,
 180       GLX_BLUE_SIZE, 1,
 181       None };
 182   XVisualInfo *vInfo = glXChooseVisual(dpy, DefaultScreen(dpy), attribs);
 183   if (!vInfo)
 184     fatal_error("No visuals found");
 185
 186   // using a X11 Window instead of a GLXPixmap does not crash
 187   // fglrx in indirect rendering. bug 680644
 188   Window window;
 189   XSetWindowAttributes swa;
 190   swa.colormap = XCreateColormap(dpy, RootWindow(dpy, vInfo->screen),
 191                                  vInfo->visual, AllocNone);
 192
 193   swa.border_pixel = 0;
 194   window = XCreateWindow(dpy, RootWindow(dpy, vInfo->screen),
 195                        0, 0, 16, 16,
 196                        0, vInfo->depth, InputOutput, vInfo->visual,
 197                        CWBorderPixel | CWColormap, &swa);
 198
 199   ///// Get a GL context and make it current //////
 200   GLXContext context = glXCreateContext(dpy, vInfo, nullptr, True);
 201   glXMakeCurrent(dpy, window, context);
 202
 203   ///// Look for this symbol to determine texture_from_pixmap support /////
 204   void* glXBindTexImageEXT = glXGetProcAddress("glXBindTexImageEXT");
 205
 206   ///// Get GL vendor/renderer/versions strings /////
 207   enum { bufsize = 1024 };
 208   char buf[bufsize];
 209   const GLubyte *vendorString = glGetString(GL_VENDOR);
 210   const GLubyte *rendererString = glGetString(GL_RENDERER);
 211   const GLubyte *versionString = glGetString(GL_VERSION);
 212
 213   if (!vendorString || !rendererString || !versionString)
 214     fatal_error("glGetString returned null");
 215
 216   int length = snprintf(buf, bufsize,
 217                         "VENDOR\n%s\nRENDERER\n%s\nVERSION\n%s\nTFP\n%s\n",
 218                         vendorString,
 219                         rendererString,
 220                         versionString,
 221                         glXBindTexImageEXT ? "TRUE" : "FALSE");
 222   if (length >= bufsize)
 223     fatal_error("GL strings length too large for buffer size");
 224
 225   ///// Clean up. Indeed, the parent process might fail to kill us (e.g. if it doesn't need to check GL info)
 226   ///// so we might be staying alive for longer than expected, so it's important to consume as little memory as
 227   ///// possible. Also we want to check that we're able to do that too without generating X errors.
 228   glXMakeCurrent(dpy, None, nullptr); // must release the GL context before destroying it
 229   glXDestroyContext(dpy, context);
 230   XDestroyWindow(dpy, window);
 231   XFreeColormap(dpy, swa.colormap);
 232   XCloseDisplay(dpy);
 233   dlclose(libgl);
 234
 235   ///// Finally write data to the pipe
 236   write(write_end_of_the_pipe, buf, length);
 237 }
 238
 239 /** \returns true in the child glxtest process, false in the parent process */
 240 bool fire_glxtest_process()
 241 {
 242   int pfd[2];
 243   if (pipe(pfd) == -1) {
 244       perror("pipe");
 245       return false;
 246   }
 247   pid_t pid = fork();
 248   if (pid < 0) {
 249       perror("fork");
 250       close(pfd[0]);
 251       close(pfd[1]);
 252       return false;
 253   }
 254   if (pid == 0) {
 255       close(pfd[0]);
 256       write_end_of_the_pipe = pfd[1];
 257       glxtest();
 258       close(pfd[1]);
 259       return true;
 260   }
 261
 262   close(pfd[1]);
 263   mozilla::widget::glxtest_pipe = pfd[0];
 264   mozilla::widget::glxtest_pid = pid;
 265   return false;
 266 }