vcl/unx/glxtest.cxx

   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 // Explanation: See bug 639842. Safely getting GL driver info on X11 is hard, because the only way to do
  11 // that is to create a GL context and call glGetString(), but with bad drivers,
  12 // just creating a GL context may crash.
  13 //
  14 // This file implements the idea to do that in a separate process.
  15 //
  16 // The only non-static function here is fire_glxtest_process(). It creates a pipe, publishes its 'read' end as the
  17 // mozilla::widget::glxtest_pipe global variable, forks, and runs that GLX probe in the child process,
  18 // which runs the glxtest() static function. This creates a X connection, a GLX context, calls glGetString, and writes that
  19 // to the 'write' end of the pipe.
  20
  21 #include <cstdio>
  22 #include <cstdlib>
  23 #include <unistd.h>
  24 #include <dlfcn.h>
  25 #include <fcntl.h>
  26 #include "stdint.h"
  27 #include <string.h>
  28
  29 #include <vcl/opengl/glxtest.hxx>
  30
  31 #ifdef __SUNPRO_CC
  32 #include <stdio.h>
  33 #endif
  34
  35 #include "X11/Xlib.h"
  36 #include "X11/Xutil.h"
  37
  38 // stuff from glx.h
  39 typedef struct __GLXcontextRec *GLXContext;
  40 typedef XID GLXPixmap;
  41 typedef XID GLXDrawable;
  42 /* GLX 1.3 and later */
  43 typedef struct __GLXFBConfigRec *GLXFBConfig;
  44 typedef XID GLXFBConfigID;
  45 typedef XID GLXContextID;
  46 typedef XID GLXWindow;
  47 typedef XID GLXPbuffer;
  48 #define GLX_RGBA        4
  49 #define GLX_RED_SIZE    8
  50 #define GLX_GREEN_SIZE  9
  51 #define GLX_BLUE_SIZE   10
  52
  53 // stuff from gl.h
  54 typedef uint8_t GLubyte;
  55 typedef uint32_t GLenum;
  56 #define GL_VENDOR       0x1F00
  57 #define GL_RENDERER     0x1F01
  58 #define GL_VERSION      0x1F02
  59
  60 // the write end of the pipe, which we're going to write to
  61 static int write_end_of_the_pipe = -1;
  62
  63 // C++ standard collides with C standard in that it doesn't allow casting void* to function pointer types.
  64 // So the work-around is to convert first to size_t.
  65 // http://www.trilithium.com/johan/2004/12/problem-with-dlsym/
  66 template<typename func_ptr_type>
  67 static func_ptr_type cast(void *ptr)
  68 {
  69   return reinterpret_cast<func_ptr_type>(
  70            reinterpret_cast<size_t>(ptr)
  71          );
  72 }
  73
  74 static void fatal_error(const char *str)
  75 {
  76   int length = strlen(str);
  77   if (write(write_end_of_the_pipe, str, length) != length
  78       || write(write_end_of_the_pipe, "\n", 1) != 1)
  79   {
  80       /* Cannot write to pipe. Fall through to call _exit */
  81   }
  82   _exit(EXIT_FAILURE);
  83 }
  84
  85 static int
  86 x_error_handler(Display *, XErrorEvent *ev)
  87 {
  88   enum { bufsize = 1024 };
  89   char buf[bufsize];
  90   int length = snprintf(buf, bufsize,
  91                         "X error occurred in GLX probe, error_code=%d, request_code=%d, minor_code=%d\n",
  92                         ev->error_code,
  93                         ev->request_code,
  94                         ev->minor_code);
  95   if (write(write_end_of_the_pipe, buf, length) != length)
  96   {
  97       /* Cannot write to pipe. Fall through to call _exit */
  98   }
  99   _exit(EXIT_FAILURE);
 100   return 0;
 101 }
 102
 103 void glxtest()
 104 {
 105   // we want to redirect to /dev/null stdout, stderr, and while we're at it,
 106   // any PR logging file descriptors. To that effect, we redirect all positive
 107   // file descriptors up to what open() returns here. In particular, 1 is stdout and 2 is stderr.
 108   int fd = open("/dev/null", O_WRONLY);
 109   if (fd == -1)
 110     fatal_error("could not redirect stdout+stderr");
 111   for (int i = 1; i < fd; i++)
 112     dup2(fd, i);
 113   close(fd);
 114
 115   ///// Open libGL and load needed symbols /////
 116 #ifdef __OpenBSD__
 117   #define LIBGL_FILENAME "libGL.so"
 118 #else
 119   #define LIBGL_FILENAME "libGL.so.1"
 120 #endif
 121   void *libgl = dlopen(LIBGL_FILENAME, RTLD_LAZY);
 122   if (!libgl)
 123     fatal_error("Unable to load " LIBGL_FILENAME);
 124
 125   typedef void* (* PFNGLXGETPROCADDRESS) (const char *);
 126   PFNGLXGETPROCADDRESS glXGetProcAddress = cast<PFNGLXGETPROCADDRESS>(dlsym(libgl, "glXGetProcAddress"));
 127
 128   if (!glXGetProcAddress)
 129     fatal_error("Unable to find glXGetProcAddress in " LIBGL_FILENAME);
 130
 131   typedef GLXFBConfig* (* PFNGLXQUERYEXTENSION) (Display *, int *, int *);
 132   PFNGLXQUERYEXTENSION glXQueryExtension = cast<PFNGLXQUERYEXTENSION>(glXGetProcAddress("glXQueryExtension"));
 133
 134   typedef GLXFBConfig* (* PFNGLXQUERYVERSION) (Display *, int *, int *);
 135   PFNGLXQUERYVERSION glXQueryVersion = cast<PFNGLXQUERYVERSION>(dlsym(libgl, "glXQueryVersion"));
 136
 137   typedef XVisualInfo* (* PFNGLXCHOOSEVISUAL) (Display *, int, int *);
 138   PFNGLXCHOOSEVISUAL glXChooseVisual = cast<PFNGLXCHOOSEVISUAL>(glXGetProcAddress("glXChooseVisual"));
 139
 140   typedef GLXContext (* PFNGLXCREATECONTEXT) (Display *, XVisualInfo *, GLXContext, Bool);
 141   PFNGLXCREATECONTEXT glXCreateContext = cast<PFNGLXCREATECONTEXT>(glXGetProcAddress("glXCreateContext"));
 142
 143   typedef Bool (* PFNGLXMAKECURRENT) (Display*, GLXDrawable, GLXContext);
 144   PFNGLXMAKECURRENT glXMakeCurrent = cast<PFNGLXMAKECURRENT>(glXGetProcAddress("glXMakeCurrent"));
 145
 146   typedef void (* PFNGLXDESTROYCONTEXT) (Display*, GLXContext);
 147   PFNGLXDESTROYCONTEXT glXDestroyContext = cast<PFNGLXDESTROYCONTEXT>(glXGetProcAddress("glXDestroyContext"));
 148
 149   typedef GLubyte* (* PFNGLGETSTRING) (GLenum);
 150   PFNGLGETSTRING glGetString = cast<PFNGLGETSTRING>(glXGetProcAddress("glGetString"));
 151
 152   if (!glXQueryExtension ||
 153       !glXQueryVersion ||
 154       !glXChooseVisual ||
 155       !glXCreateContext ||
 156       !glXMakeCurrent ||
 157       !glXDestroyContext ||
 158       !glGetString)
 159   {
 160     fatal_error("glXGetProcAddress couldn't find required functions");
 161   }
 162   ///// Open a connection to the X server /////
 163   Display *dpy = XOpenDisplay(nullptr);
 164   if (!dpy)
 165     fatal_error("Unable to open a connection to the X server");
 166
 167   ///// Check that the GLX extension is present /////
 168   if (!glXQueryExtension(dpy, nullptr, nullptr))
 169     fatal_error("GLX extension missing");
 170
 171   XSetErrorHandler(x_error_handler);
 172
 173   ///// Get a visual /////
 174    int attribs[] = {
 175       GLX_RGBA,
 176       GLX_RED_SIZE, 1,
 177       GLX_GREEN_SIZE, 1,
 178       GLX_BLUE_SIZE, 1,
 179       None };
 180   XVisualInfo *vInfo = glXChooseVisual(dpy, DefaultScreen(dpy), attribs);
 181   if (!vInfo)
 182     fatal_error("No visuals found");
 183
 184   // using a X11 Window instead of a GLXPixmap does not crash
 185   // fglrx in indirect rendering. bug 680644
 186   Window window;
 187   XSetWindowAttributes swa;
 188   swa.colormap = XCreateColormap(dpy, RootWindow(dpy, vInfo->screen),
 189                                  vInfo->visual, AllocNone);
 190
 191   swa.border_pixel = 0;
 192   window = XCreateWindow(dpy, RootWindow(dpy, vInfo->screen),
 193                        0, 0, 16, 16,
 194                        0, vInfo->depth, InputOutput, vInfo->visual,
 195                        CWBorderPixel | CWColormap, &swa);
 196
 197   ///// Get a GL context and make it current //////
 198   GLXContext context = glXCreateContext(dpy, vInfo, nullptr, True);
 199   glXMakeCurrent(dpy, window, context);
 200
 201   ///// Look for this symbol to determine texture_from_pixmap support /////
 202   void* glXBindTexImageEXT = glXGetProcAddress("glXBindTexImageEXT");
 203
 204   ///// Get GL vendor/renderer/versions strings /////
 205   enum { bufsize = 1024 };
 206   char buf[bufsize];
 207   const GLubyte *vendorString = glGetString(GL_VENDOR);
 208   const GLubyte *rendererString = glGetString(GL_RENDERER);
 209   const GLubyte *versionString = glGetString(GL_VERSION);
 210
 211   if (!vendorString || !rendererString || !versionString)
 212     fatal_error("glGetString returned null");
 213
 214   int length = snprintf(buf, bufsize,
 215                         "VENDOR\n%s\nRENDERER\n%s\nVERSION\n%s\nTFP\n%s\n",
 216                         vendorString,
 217                         rendererString,
 218                         versionString,
 219                         glXBindTexImageEXT ? "TRUE" : "FALSE");
 220   if (length >= bufsize)
 221     fatal_error("GL strings length too large for buffer size");
 222
 223   ///// Clean up. Indeed, the parent process might fail to kill us (e.g. if it doesn't need to check GL info)
 224   ///// so we might be staying alive for longer than expected, so it's important to consume as little memory as
 225   ///// possible. Also we want to check that we're able to do that too without generating X errors.
 226   glXMakeCurrent(dpy, None, nullptr); // must release the GL context before destroying it
 227   glXDestroyContext(dpy, context);
 228   XDestroyWindow(dpy, window);
 229   XFreeColormap(dpy, swa.colormap);
 230   XFree(vInfo);
 231
 232 #ifdef NS_FREE_PERMANENT_DATA // conditionally defined in nscore.h, don't forget to #include it above
 233   XCloseDisplay(dpy);
 234 #else
 235   // This XSync call wanted to be instead:
 236   //   XCloseDisplay(dpy);
 237   // but this can cause 1-minute stalls on certain setups using Nouveau, see bug 973192
 238   XSync(dpy, False);
 239 #endif
 240
 241   dlclose(libgl);
 242
 243   ///// Finally write data to the pipe
 244   if (write(write_end_of_the_pipe, buf, length) != length)
 245     fatal_error("Could not write to pipe");
 246 }
 247
 248 /** \returns true in the child glxtest process, false in the parent process */
 249 bool fire_glxtest_process()
 250 {
 251   int pfd[2];
 252   if (pipe(pfd) == -1) {
 253       perror("pipe");
 254       return false;
 255   }
 256   pid_t pid = fork();
 257   if (pid < 0) {
 258       perror("fork");
 259       close(pfd[0]);
 260       close(pfd[1]);
 261       return false;
 262   }
 263   // The child exits early to avoid running the full shutdown sequence and avoid conflicting with threads
 264   // we have already spawned (like the profiler).
 265   if (pid == 0) {
 266       close(pfd[0]);
 267       write_end_of_the_pipe = pfd[1];
 268       glxtest();
 269       close(pfd[1]);
 270       _exit(0);
 271   }
 272
 273   close(pfd[1]);
 274   int* glxtest_pipe = getGlxPipe();
 275   *glxtest_pipe = pfd[0];
 276   pid_t* glxtest_pid = getGlxPid();
 277   *glxtest_pid = pid;
 278   return true;
 279 }