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 #include <signal.h>
  29
  30 #include <sys/wait.h>
  31
  32 #include <opengl/x11/glxtest.hxx>
  33
  34 #ifdef __SUNPRO_CC
  35 #include <stdio.h>
  36 #endif
  37
  38 #include <X11/Xlib.h>
  39 #include <X11/Xutil.h>
  40
  41 #include <sal/log.hxx>
  42
  43 // stuff from glx.h
  44 typedef struct __GLXcontextRec *GLXContext;
  45 typedef XID GLXPixmap;
  46 typedef XID GLXDrawable;
  47 /* GLX 1.3 and later */
  48 typedef struct __GLXFBConfigRec *GLXFBConfig;
  49 #define GLX_RGBA        4
  50 #define GLX_RED_SIZE    8
  51 #define GLX_GREEN_SIZE  9
  52 #define GLX_BLUE_SIZE   10
  53
  54 // stuff from gl.h
  55 typedef uint8_t GLubyte;
  56 typedef uint32_t GLenum;
  57 #define GL_VENDOR       0x1F00
  58 #define GL_RENDERER     0x1F01
  59 #define GL_VERSION      0x1F02
  60
  61 // the write end of the pipe, which we're going to write to
  62 static int write_end_of_the_pipe = -1;
  63
  64 // C++ standard collides with C standard in that it doesn't allow casting void* to function pointer types.
  65 // So the work-around is to convert first to size_t.
  66 // http://www.trilithium.com/johan/2004/12/problem-with-dlsym/
  67 template<typename func_ptr_type>
  68 static func_ptr_type cast(void *ptr)
  69 {
  70   return reinterpret_cast<func_ptr_type>(
  71            reinterpret_cast<size_t>(ptr)
  72          );
  73 }
  74
  75 static void fatal_error(const char *str)
  76 {
  77   int length = strlen(str);
  78   if (write(write_end_of_the_pipe, str, length) != length
  79       || write(write_end_of_the_pipe, "\n", 1) != 1)
  80   {
  81       /* Cannot write to pipe. Fall through to call _exit */
  82   }
  83   _exit(EXIT_FAILURE);
  84 }
  85
  86 static int
  87 x_error_handler(Display *, XErrorEvent *ev)
  88 {
  89   enum { bufsize = 1024 };
  90   char buf[bufsize];
  91   int length = snprintf(buf, bufsize,
  92                         "X error occurred in GLX probe, error_code=%d, request_code=%d, minor_code=%d\n",
  93                         ev->error_code,
  94                         ev->request_code,
  95                         ev->minor_code);
  96   if (write(write_end_of_the_pipe, buf, length) != length)
  97   {
  98       /* Cannot write to pipe. Fall through to call _exit */
  99   }
 100   _exit(EXIT_FAILURE);
 101   return 0;
 102 }
 103
 104 static void glxtest()
 105 {
 106   signal(SIGPIPE, SIG_IGN);
 107   // we want to redirect to /dev/null stdout, stderr, and while we're at it,
 108   // any PR logging file descriptors. To that effect, we redirect all positive
 109   // file descriptors up to what open() returns here. In particular, 1 is stdout and 2 is stderr.
 110   int fd = open("/dev/null", O_WRONLY);
 111   if (fd == -1)
 112     fatal_error("could not redirect stdout+stderr");
 113   for (int i = 1; i < fd; i++)
 114     dup2(fd, i);
 115   close(fd);
 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   XFree(vInfo);
 233
 234 #ifdef NS_FREE_PERMANENT_DATA // conditionally defined in nscore.h, don't forget to #include it above
 235   XCloseDisplay(dpy);
 236 #else
 237   // This XSync call wanted to be instead:
 238   //   XCloseDisplay(dpy);
 239   // but this can cause 1-minute stalls on certain setups using Nouveau, see bug 973192
 240   XSync(dpy, False);
 241 #endif
 242
 243   dlclose(libgl);
 244
 245   ///// Finally write data to the pipe
 246   if (write(write_end_of_the_pipe, buf, length) != length)
 247     fatal_error("Could not write to pipe");
 248 }
 249
 250 /** \returns true in the child glxtest process, false in the parent process */
 251 bool fire_glxtest_process()
 252 {
 253   int pfd[2];
 254   if (pipe(pfd) == -1) {
 255       perror("pipe");
 256       return false;
 257   }
 258   pid_t pid = fork();
 259   if (pid < 0) {
 260       perror("fork");
 261       close(pfd[0]);
 262       close(pfd[1]);
 263       return false;
 264   }
 265   // The child exits early to avoid running the full shutdown sequence and avoid conflicting with threads
 266   // we have already spawned (like the profiler).
 267   if (pid == 0) {
 268       close(pfd[0]);
 269       write_end_of_the_pipe = pfd[1];
 270       glxtest();
 271       close(pfd[1]);
 272       _exit(0);
 273   }
 274
 275   close(pfd[1]);
 276   int* glxtest_pipe = getGlxPipe();
 277   *glxtest_pipe = pfd[0];
 278   pid_t* glxtest_pid = getGlxPid();
 279   *glxtest_pid = pid;
 280   return true;
 281 }
 282
 283 void reap_glxtest_process() {
 284     pid_t * pid = getGlxPid();
 285     if (*pid != 0) {
 286         // Use WNOHANG, as it is probably better to have a (rather harmless) zombie child process
 287         // hanging around for the duration of the calling process, than to potentially block the
 288         // calling process here:
 289         pid_t e = waitpid(*pid, nullptr, WNOHANG);
 290         SAL_INFO_IF(
 291             e <= 0, "vcl.opengl", "waiting for glxtest process " << *pid << " failed with " << e);
 292     }
 293 }