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/**************************************************************************

 *

 * Copyright 2008 Tungsten Graphics, Inc., Cedar Park, Texas.

 * Copyright 2009-2010 Chia-I Wu 

 * Copyright 2010-2011 LunarG, Inc.

 * All Rights Reserved.

 *

 * 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, sub license, 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.

 *

 **************************************************************************/

/**

 * Functions for choosing and opening/loading device drivers.

 */

#include 

#include 

#include 

#include 

#include "eglstring.h"

#include "egldefines.h"

#include "egldisplay.h"

#include "egldriver.h"

#include "egllog.h"

#include "eglmutex.h"

typedef unsigned int lib_handle;

lib_handle load_library(const char *name);

void *get_proc_address(lib_handle lib, char *proc_name);

typedef struct _egl_module {

   char *Path;

   _EGLMain_t BuiltIn;

   void *Handle;

   _EGLDriver *Driver;

} _EGLModule;

static _EGL_DECLARE_MUTEX(_eglModuleMutex);

static _EGLArray *_eglModules;

const struct {

   const char *name;

   _EGLMain_t main;

} _eglBuiltInDrivers[] = {

#ifdef _EGL_BUILT_IN_DRIVER_GALLIUM

   { "egl_gallium", _eglBuiltInDriverGALLIUM },

#endif

#ifdef _EGL_BUILT_IN_DRIVER_DRI2

   { "egl_dri2", _eglBuiltInDriverDRI2 },

#endif

#ifdef _EGL_BUILT_IN_DRIVER_GLX

   { "egl_glx", _eglBuiltInDriverGLX },

#endif

   { NULL, NULL }

};

/**

 * Wrappers for dlopen/dlclose()

 */

#if defined(_EGL_OS_WINDOWS)

typedef HMODULE lib_handle;

static HMODULE

open_library(const char *filename)

{

   return LoadLibrary(filename);

}

static void

close_library(HMODULE lib)

{

   FreeLibrary(lib);

}

static const char *

library_suffix(void)

{

   return ".dll";

}

#elif defined(_EGL_OS_UNIX)

typedef void * lib_handle;

static void *

open_library(const char *filename)

{

   return dlopen(filename, RTLD_LAZY);

}

static void

close_library(void *lib)

{

   dlclose(lib);

}

static const char *

library_suffix(void)

{

   return ".so";

}

#endif

/**

 * Open the named driver and find its bootstrap function: _eglMain().

 */

static _EGLMain_t

_eglOpenLibrary(const char *driverPath, lib_handle *handle)

{

   lib_handle lib;

   _EGLMain_t mainFunc = NULL;

   const char *error = "unknown error";

   assert(driverPath);

   _eglLog(_EGL_DEBUG, "dlopen(%s)", driverPath);

   lib = load_library(driverPath);

   if (!lib) {

      _eglLog(_EGL_WARNING, "Could not open driver %s (%s)",

              driverPath, error);

      return NULL;

   }

   mainFunc = (_EGLMain_t) get_proc_address(lib, "_eglMain");

   if (!mainFunc) {

      _eglLog(_EGL_WARNING, "_eglMain not found in %s (%s)",

              driverPath, error);

      return NULL;

   }

   *handle = lib;

   return mainFunc;

}

/**

 * Load a module and create the driver object.

 */

static EGLBoolean

_eglLoadModule(_EGLModule *mod)

{

   _EGLMain_t mainFunc;

   lib_handle lib;

   _EGLDriver *drv;

   if (mod->Driver)

      return EGL_TRUE;

   if (mod->BuiltIn) {

      lib = (lib_handle) NULL;

      mainFunc = mod->BuiltIn;

   }

   else {

      mainFunc = _eglOpenLibrary(mod->Path, &lib);

      if (!mainFunc)

         return EGL_FALSE;

   }

   drv = mainFunc(NULL);

   if (!drv) {

      return EGL_FALSE;

   }

   if (!drv->Name) {

      _eglLog(_EGL_WARNING, "Driver loaded from %s has no name", mod->Path);

      drv->Name = "UNNAMED";

   }

   mod->Handle = (void *) lib;

   mod->Driver = drv;

   return EGL_TRUE;

}

/**

 * Unload a module.

 */

static void

_eglUnloadModule(_EGLModule *mod)

{

#if defined(_EGL_OS_UNIX)

   /* destroy the driver */

   if (mod->Driver && mod->Driver->Unload)

      mod->Driver->Unload(mod->Driver);

   /*

    * XXX At this point (atexit), the module might be the last reference to

    * libEGL.  Closing the module might unmap libEGL and give problems.

    */

#if 0

   if (mod->Handle)

      close_library(mod->Handle);

#endif

#elif defined(_EGL_OS_WINDOWS)

   /* XXX Windows unloads DLLs before atexit */

#endif

   mod->Driver = NULL;

   mod->Handle = NULL;

}

/**

 * Add a module to the module array.

 */

static _EGLModule *

_eglAddModule(const char *path)

{

   _EGLModule *mod;

   EGLint i;

   if (!_eglModules) {

      _eglModules = _eglCreateArray("Module", 8);

      if (!_eglModules)

         return NULL;

   }

   /* find duplicates */

   for (i = 0; i < _eglModules->Size; i++) {

      mod = _eglModules->Elements[i];

      if (strcmp(mod->Path, path) == 0)

         return mod;

   }

   /* allocate a new one */

   mod = calloc(1, sizeof(*mod));

   if (mod) {

      mod->Path = _eglstrdup(path);

      if (!mod->Path) {

         free(mod);

         mod = NULL;

      }

   }

   if (mod) {

      _eglAppendArray(_eglModules, (void *) mod);

      _eglLog(_EGL_DEBUG, "added %s to module array", mod->Path);

   }

   return mod;

}

/**

 * Free a module.

 */

static void

_eglFreeModule(void *module)

{

   _EGLModule *mod = (_EGLModule *) module;

   _eglUnloadModule(mod);

   free(mod->Path);

   free(mod);

}

#if 0

/**

 * A loader function for use with _eglPreloadForEach.  The loader data is the

 * filename of the driver.   This function stops on the first valid driver.

 */

static EGLBoolean

_eglLoaderFile(const char *dir, size_t len, void *loader_data)

{

   char path[1024];

   const char *filename = (const char *) loader_data;

   size_t flen = strlen(filename);

   /* make a full path */

   if (len + flen + 2 > sizeof(path))

      return EGL_TRUE;

   if (len) {

      memcpy(path, dir, len);

      path[len++] = '/';

   }

   memcpy(path + len, filename, flen);

   len += flen;

   path[len] = '\0';

   if (library_suffix()) {

      const char *suffix = library_suffix();

      size_t slen = strlen(suffix);

      const char *p;

      EGLBoolean need_suffix;

      p = filename + flen - slen;

      need_suffix = (p < filename || strcmp(p, suffix) != 0);

      if (need_suffix) {

         /* overflow */

         if (len + slen + 1 > sizeof(path))

            return EGL_TRUE;

         strcpy(path + len, suffix);

      }

   }

#if defined(_EGL_OS_UNIX)

   /* check if the file exists */

   if (access(path, F_OK))

      return EGL_TRUE;

#endif

   _eglAddModule(path);

   return EGL_TRUE;

}

/**

 * Run the callback function on each driver directory.

 *

 * The process may end prematurely if the callback function returns false.

 */

static void

_eglPreloadForEach(const char *search_path,

                   EGLBoolean (*loader)(const char *, size_t, void *),

                   void *loader_data)

{

   const char *cur, *next;

   size_t len;

   cur = search_path;

   while (cur) {

      next = strchr(cur, ':');

      len = (next) ? next - cur : strlen(cur);

      if (!loader(cur, len, loader_data))

         break;

      cur = (next) ? next + 1 : NULL;

   }

}

/**

 * Return a list of colon-separated driver directories.

 */

static const char *

_eglGetSearchPath(void)

{

   static char search_path[1024];

#if defined(_EGL_OS_UNIX) || defined(_EGL_OS_WINDOWS)

   if (search_path[0] == '\0') {

      char *buf = search_path;

      size_t len = sizeof(search_path);

      EGLBoolean use_env;

      char dir_sep;

      int ret;

#if defined(_EGL_OS_UNIX)

      use_env = (geteuid() == getuid() && getegid() == getgid());

      dir_sep = '/';

#else

      use_env = EGL_TRUE;

      dir_sep = '\\';

#endif

      if (use_env) {

         char *p;

         /* extract the dirname from EGL_DRIVER */

         p = getenv("EGL_DRIVER");

         if (p && strchr(p, dir_sep)) {

            ret = _eglsnprintf(buf, len, "%s", p);

            if (ret > 0 && ret < len) {

               p = strrchr(buf, dir_sep);

               *p++ = ':';

               len -= p - buf;

               buf = p;

            }

         }

         /* append EGL_DRIVERS_PATH */

         p = getenv("EGL_DRIVERS_PATH");

         if (p) {

            ret = _eglsnprintf(buf, len, "%s:", p);

            if (ret > 0 && ret < len) {

               buf += ret;

               len -= ret;

            }

         }

      }

      else {

         _eglLog(_EGL_DEBUG,

               "ignore EGL_DRIVERS_PATH for setuid/setgid binaries");

      }

      ret = _eglsnprintf(buf, len, "%s", _EGL_DRIVER_SEARCH_DIR);

      if (ret < 0 || ret >= len)

         search_path[0] = '\0';

      _eglLog(_EGL_DEBUG, "EGL search path is %s", search_path);

   }

#endif /* defined(_EGL_OS_UNIX) || defined(_EGL_OS_WINDOWS) */

   return search_path;

}

/**

 * Add the user driver to the module array.

 *

 * The user driver is specified by EGL_DRIVER.

 */

static EGLBoolean

_eglAddUserDriver(void)

{

   const char *search_path = _eglGetSearchPath();

   char *env;

   size_t name_len = 0;

   env = getenv("EGL_DRIVER");

#if defined(_EGL_OS_UNIX)

   if (env && strchr(env, '/')) {

      search_path = "";

      if ((geteuid() != getuid() || getegid() != getgid())) {

         _eglLog(_EGL_DEBUG,

               "ignore EGL_DRIVER for setuid/setgid binaries");

         env = NULL;

      }

   }

   else if (env) {

      char *suffix = strchr(env, '.');

      name_len = (suffix) ? suffix - env : strlen(env);

   }

#else

   if (env)

      name_len = strlen(env);

#endif /* _EGL_OS_UNIX */

   /*

    * Try built-in drivers first if we know the driver name.  This makes sure

    * we do not load the outdated external driver that is still on the

    * filesystem.

    */

   if (name_len) {

      _EGLModule *mod;

      EGLint i;

      for (i = 0; _eglBuiltInDrivers[i].name; i++) {

         if (strlen(_eglBuiltInDrivers[i].name) == name_len &&

             !strncmp(_eglBuiltInDrivers[i].name, env, name_len)) {

            mod = _eglAddModule(env);

            if (mod)

               mod->BuiltIn = _eglBuiltInDrivers[i].main;

            return EGL_TRUE;

         }

      }

   }

   /* otherwise, treat env as a path */

   if (env) {

      _eglPreloadForEach(search_path, _eglLoaderFile, (void *) env);

      return EGL_TRUE;

   }

   return EGL_FALSE;

}

/**

 * Add egl_gallium to the module array.

 */

static void

_eglAddGalliumDriver(void)

{

#ifndef _EGL_BUILT_IN_DRIVER_GALLIUM

   void *external = (void *) "egl_gallium";

   _eglPreloadForEach(_eglGetSearchPath(), _eglLoaderFile, external);

#endif

}

#endif

/**

 * Add built-in drivers to the module array.

 */

static void

_eglAddBuiltInDrivers(void)

{

   _EGLModule *mod;

   EGLint i;

   for (i = 0; _eglBuiltInDrivers[i].name; i++) {

      mod = _eglAddModule(_eglBuiltInDrivers[i].name);

      if (mod)

         mod->BuiltIn = _eglBuiltInDrivers[i].main;

   }

}

/**

 * Add drivers to the module array.  Drivers will be loaded as they are matched

 * to displays.

 */

static EGLBoolean

_eglAddDrivers(void)

{

   if (_eglModules)

      return EGL_TRUE;

//   if (!_eglAddUserDriver()) {

      /*

       * Add other drivers only when EGL_DRIVER is not set.  The order here

       * decides the priorities.

       */

//      _eglAddGalliumDriver();

      _eglAddBuiltInDrivers();

//   }

   return (_eglModules != NULL);

}

/**

 * A helper function for _eglMatchDriver.  It finds the first driver that can

 * initialize the display and return.

 */

static _EGLDriver *

_eglMatchAndInitialize(_EGLDisplay *dpy)

{

   _EGLDriver *drv = NULL;

   EGLint i = 0;

   if (!_eglAddDrivers()) {

      _eglLog(_EGL_WARNING, "failed to find any driver");

      return NULL;

   }

   if (dpy->Driver) {

      drv = dpy->Driver;

      /* no re-matching? */

      if (!drv->API.Initialize(drv, dpy))

         drv = NULL;

      return drv;

   }

   while (i < _eglModules->Size) {

      _EGLModule *mod = (_EGLModule *) _eglModules->Elements[i];

      if (!_eglLoadModule(mod)) {

         /* remove invalid modules */

         _eglEraseArray(_eglModules, i, _eglFreeModule);

         continue;

      }

      if (mod->Driver->API.Initialize(mod->Driver, dpy)) {

         drv = mod->Driver;

         break;

      }

      else {

         i++;

      }

   }

   return drv;

}

/**

 * Match a display to a driver.  The display is initialized unless test_only is

 * true.  The matching is done by finding the first driver that can initialize

 * the display.

 */

_EGLDriver *

_eglMatchDriver(_EGLDisplay *dpy, EGLBoolean test_only)

{

   _EGLDriver *best_drv;

   assert(!dpy->Initialized);

   _eglLockMutex(&_eglModuleMutex);

   /* set options */

   dpy->Options.TestOnly = test_only;

   dpy->Options.UseFallback = EGL_FALSE;

   best_drv = _eglMatchAndInitialize(dpy);

   if (!best_drv) {

      dpy->Options.UseFallback = EGL_TRUE;

      best_drv = _eglMatchAndInitialize(dpy);

   }

   _eglUnlockMutex(&_eglModuleMutex);

   if (best_drv) {

      _eglLog(_EGL_DEBUG, "the best driver is %s%s",

            best_drv->Name, (test_only) ? " (test only) " : "");

      if (!test_only) {

         dpy->Driver = best_drv;

         dpy->Initialized = EGL_TRUE;

      }

   }

   return best_drv;

}

__eglMustCastToProperFunctionPointerType

_eglGetDriverProc(const char *procname)

{

   EGLint i;

   _EGLProc proc = NULL;

   if (!_eglModules) {

      /* load the driver for the default display */

      EGLDisplay egldpy = eglGetDisplay(EGL_DEFAULT_DISPLAY);

      _EGLDisplay *dpy = _eglLookupDisplay(egldpy);

      if (!dpy || !_eglMatchDriver(dpy, EGL_TRUE))

         return NULL;

   }

   for (i = 0; i < _eglModules->Size; i++) {

      _EGLModule *mod = (_EGLModule *) _eglModules->Elements[i];

      if (!mod->Driver)

         break;

      proc = mod->Driver->API.GetProcAddress(mod->Driver, procname);

      if (proc)

         break;

   }

   return proc;

}

/**

 * Unload all drivers.

 */

void

_eglUnloadDrivers(void)

{

   /* this is called at atexit time */

   if (_eglModules) {

      _eglDestroyArray(_eglModules, _eglFreeModule);

      _eglModules = NULL;

   }

}

#if 0

/**

 * Invoke a callback function on each EGL search path.

 *

 * The first argument of the callback function is the name of the search path.

 * The second argument is the length of the name.

 */

void

_eglSearchPathForEach(EGLBoolean (*callback)(const char *, size_t, void *),

                      void *callback_data)

{

   const char *search_path = _eglGetSearchPath();

   _eglPreloadForEach(search_path, callback, callback_data);

}

#endif