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

Copyright 1998-1999 Precision Insight, Inc., Cedar Park, Texas.
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 NON-INFRINGEMENT.
IN NO EVENT SHALL PRECISION INSIGHT AND/OR ITS SUPPLIERS 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.

**************************************************************************/
/* $XFree86: xc/lib/GL/dri/dri_glx.c,v 1.14 2003/07/16 00:54:00 dawes Exp $ */

/*
 * Authors:
 *   Kevin E. Martin <kevin@precisioninsight.com>
 *   Brian Paul <brian@precisioninsight.com>
 *
 */

#ifdef GLX_DIRECT_RENDERING

#include <unistd.h>
#include <X11/Xlibint.h>
#include <X11/extensions/Xext.h>
#include <X11/extensions/extutil.h>
#include "glxclient.h"
#include "xf86dri.h"
#include "sarea.h"
#include <stdio.h>
#include <dlfcn.h>
#include "dri_glx.h"
#include <sys/types.h>
#include <stdarg.h>

#ifndef RTLD_NOW
#define RTLD_NOW 0
#endif
#ifndef RTLD_GLOBAL
#define RTLD_GLOBAL 0
#endif


#ifndef DEFAULT_DRIVER_DIR
/* this is normally defined in Mesa/configs/default with DRI_DRIVER_SEARCH_PATH */
#define DEFAULT_DRIVER_DIR "/usr/X11R6/lib/modules/dri"
#endif

static __DRIdriver *Drivers = NULL;


/*
 * printf wrappers
 */

static void InfoMessageF(const char *f, ...)
{
    va_list args;
    const char *env;

    if ((env = getenv("LIBGL_DEBUG")) && strstr(env, "verbose")) {
	fprintf(stderr, "libGL: ");
	va_start(args, f);
	vfprintf(stderr, f, args);
	va_end(args);
    }
}

static void ErrorMessageF(const char *f, ...)
{
    va_list args;

    if (getenv("LIBGL_DEBUG")) {
	fprintf(stderr, "libGL error: ");
	va_start(args, f);
	vfprintf(stderr, f, args);
	va_end(args);
    }
}


/**
 * Extract the ith directory path out of a colon-separated list of paths.  No
 * more than \c dirLen characters, including the terminating \c NUL, will be
 * written to \c dir.
 *
 * \param index  Index of path to extract (starting at zero)
 * \param paths  The colon-separated list of paths
 * \param dirLen Maximum length of result to store in \c dir
 * \param dir    Buffer to hold the extracted directory path
 *
 * \returns
 * The number of characters that would have been written to \c dir had there
 * been enough room.  This does not include the terminating \c NUL.  When
 * extraction fails, zero will be returned.
 * 
 * \todo
 * It seems like this function could be rewritten to use \c strchr.
 */
static size_t
ExtractDir(int index, const char *paths, int dirLen, char *dir)
{
   int i, len;
   const char *start, *end;

   /* find ith colon */
   start = paths;
   i = 0;
   while (i < index) {
      if (*start == ':') {
         i++;
         start++;
      }
      else if (*start == 0) {
         /* end of string and couldn't find ith colon */
         dir[0] = 0;
         return 0;
      }
      else {
         start++;
      }
   }

   while (*start == ':')
      start++;

   /* find next colon, or end of string */
   end = start + 1;
   while (*end != ':' && *end != 0) {
      end++;
   }

   /* copy string between <start> and <end> into result string */
   len = end - start;
   if (len > dirLen - 1)
      len = dirLen - 1;
   strncpy(dir, start, len);
   dir[len] = 0;

   return( end - start );
}


/**
 * Versioned name of the expected \c __driCreateNewScreen function.
 * 
 * The version of the last incompatible loader/driver inteface change is
 * appended to the name of the \c __driCreateNewScreen function.  This
 * prevents loaders from trying to load drivers that are too old.
 * 
 * \todo
 * Create a macro or something so that this is automatically updated.
 */
static const char createNewScreenName[] = "__driCreateNewScreen_20070105";


/**
 * Try to \c dlopen the named driver.
 *
 * This function adds the "_dri.so" suffix to the driver name and searches the
 * directories specified by the \c LIBGL_DRIVERS_PATH environment variable in
 * order to find the driver.
 *
 * \param driverName - a name like "tdfx", "i810", "mga", etc.
 *
 * \returns
 * A handle from \c dlopen, or \c NULL if driver file not found.
 */
static __DRIdriver *OpenDriver(const char *driverName)
{
   void *glhandle = NULL;
   char *libPaths = NULL;
   char libDir[1000];
   int i;
   __DRIdriver *driver;

   /* First, search Drivers list to see if we've already opened this driver */
   for (driver = Drivers; driver; driver = driver->next) {
      if (strcmp(driver->name, driverName) == 0) {
         /* found it */
         return driver;
      }
   }

   /* Attempt to make sure libGL symbols will be visible to the driver */
   glhandle = dlopen("libGL.so.1", RTLD_NOW | RTLD_GLOBAL);

   if (geteuid() == getuid()) {
      /* don't allow setuid apps to use LIBGL_DRIVERS_PATH */
      libPaths = getenv("LIBGL_DRIVERS_PATH");
      if (!libPaths)
         libPaths = getenv("LIBGL_DRIVERS_DIR"); /* deprecated */
   }
   if (!libPaths)
      libPaths = DEFAULT_DRIVER_DIR;

   for ( i = 0 ; ExtractDir(i, libPaths, 1000, libDir) != 0 ; i++ ) {
      char realDriverName[200];
      void *handle = NULL;

      
      /* If TLS support is enabled, try to open the TLS version of the driver
       * binary first.  If that fails, try the non-TLS version.
       */
#ifdef GLX_USE_TLS
      snprintf(realDriverName, 200, "%s/tls/%s_dri.so", libDir, driverName);
      InfoMessageF("OpenDriver: trying %s\n", realDriverName);
      handle = dlopen(realDriverName, RTLD_NOW | RTLD_GLOBAL);
#endif

      if ( handle == NULL ) {
	 snprintf(realDriverName, 200, "%s/%s_dri.so", libDir, driverName);
	 InfoMessageF("OpenDriver: trying %s\n", realDriverName);
	 handle = dlopen(realDriverName, RTLD_NOW | RTLD_GLOBAL);
      }

      if ( handle != NULL ) {
         /* allocate __DRIdriver struct */
         driver = (__DRIdriver *) Xmalloc(sizeof(__DRIdriver));
         if (!driver)
            break; /* out of memory! */
         /* init the struct */
         driver->name = __glXstrdup(driverName);
         if (!driver->name) {
            Xfree(driver);
            driver = NULL;
            break; /* out of memory! */
         }

         driver->createNewScreenFunc = (PFNCREATENEWSCREENFUNC)
            dlsym(handle, createNewScreenName);

         if ( driver->createNewScreenFunc == NULL ) {
            /* If the driver doesn't have this symbol then something's
             * really, really wrong.
             */
            ErrorMessageF("%s not defined in %s_dri.so!\n"
			  "Your driver may be too old for this libGL.\n",
			  createNewScreenName, driverName);
            Xfree(driver);
            driver = NULL;
            dlclose(handle);
            continue;
         }
         driver->handle = handle;
         /* put at head of linked list */
         driver->next = Drivers;
         Drivers = driver;
         break;
      }
      else {
	 ErrorMessageF("dlopen %s failed (%s)\n", realDriverName, dlerror());
      }
   }

   if (!driver)
      ErrorMessageF("unable to load driver: %s_dri.so\n", driverName);

   if (glhandle)
      dlclose(glhandle);

   return driver;
}


/*
 * Given a display pointer and screen number, determine the name of
 * the DRI driver for the screen. (I.e. "r128", "tdfx", etc).
 * Return True for success, False for failure.
 */
static Bool GetDriverName(Display *dpy, int scrNum, char **driverName)
{
   int directCapable;
   Bool b;
   int driverMajor, driverMinor, driverPatch;

   *driverName = NULL;

   if (!XF86DRIQueryDirectRenderingCapable(dpy, scrNum, &directCapable)) {
      ErrorMessageF("XF86DRIQueryDirectRenderingCapable failed\n");
      return False;
   }
   if (!directCapable) {
      ErrorMessageF("XF86DRIQueryDirectRenderingCapable returned false\n");
      return False;
   }

   b = XF86DRIGetClientDriverName(dpy, scrNum, &driverMajor, &driverMinor,
                                  &driverPatch, driverName);
   if (!b) {
      ErrorMessageF("Cannot determine driver name for screen %d\n", scrNum);
      return False;
   }

   InfoMessageF("XF86DRIGetClientDriverName: %d.%d.%d %s (screen %d)\n",
	     driverMajor, driverMinor, driverPatch, *driverName, scrNum);

   return True;
}


/*
 * Given a display pointer and screen number, return a __DRIdriver handle.
 * Return NULL if anything goes wrong.
 */
__DRIdriver *driGetDriver(Display *dpy, int scrNum)
{
   char *driverName;
   if (GetDriverName(dpy, scrNum, &driverName)) {
      __DRIdriver *ret;
      ret = OpenDriver(driverName);
      if (driverName)
     	 Xfree(driverName);
      return ret;
   }
   return NULL;
}


/*
 * Exported function for querying the DRI driver for a given screen.
 *
 * The returned char pointer points to a static array that will be
 * overwritten by subsequent calls.
 */
const char *glXGetScreenDriver (Display *dpy, int scrNum) {
   static char ret[32];
   char *driverName;
   if (GetDriverName(dpy, scrNum, &driverName)) {
      int len;
      if (!driverName)
	 return NULL;
      len = strlen (driverName);
      if (len >= 31)
	 return NULL;
      memcpy (ret, driverName, len+1);
      Xfree(driverName);
      return ret;
   }
   return NULL;
}


/*
 * Exported function for obtaining a driver's option list (UTF-8 encoded XML).
 *
 * The returned char pointer points directly into the driver. Therefore
 * it should be treated as a constant.
 *
 * If the driver was not found or does not support configuration NULL is
 * returned.
 *
 * Note: The driver remains opened after this function returns.
 */
const char *glXGetDriverConfig (const char *driverName) {
   __DRIdriver *driver = OpenDriver (driverName);
   if (driver)
      return dlsym (driver->handle, "__driConfigOptions");
   else
      return NULL;
}


/* This function isn't currently used.
 */
static void driDestroyDisplay(Display *dpy, void *private)
{
    __DRIdisplayPrivate *pdpyp = (__DRIdisplayPrivate *)private;

    if (pdpyp) {
        const int numScreens = ScreenCount(dpy);
        int i;
        for (i = 0; i < numScreens; i++) {
            if (pdpyp->libraryHandles[i])
                dlclose(pdpyp->libraryHandles[i]);
        }
        Xfree(pdpyp->libraryHandles);
	Xfree(pdpyp);
    }
}


/*
 * Allocate, initialize and return a __DRIdisplayPrivate object.
 * This is called from __glXInitialize() when we are given a new
 * display pointer.
 */
void *driCreateDisplay(Display *dpy, __DRIdisplay *pdisp)
{
    const int numScreens = ScreenCount(dpy);
    __DRIdisplayPrivate *pdpyp;
    int eventBase, errorBase;
    int major, minor, patch;
    int scrn;

    /* Initialize these fields to NULL in case we fail.
     * If we don't do this we may later get segfaults trying to free random
     * addresses when the display is closed.
     */
    pdisp->private = NULL;
    pdisp->destroyDisplay = NULL;

    if (!XF86DRIQueryExtension(dpy, &eventBase, &errorBase)) {
	return NULL;
    }

    if (!XF86DRIQueryVersion(dpy, &major, &minor, &patch)) {
	return NULL;
    }

    pdpyp = (__DRIdisplayPrivate *)Xmalloc(sizeof(__DRIdisplayPrivate));
    if (!pdpyp) {
	return NULL;
    }

    pdpyp->driMajor = major;
    pdpyp->driMinor = minor;
    pdpyp->driPatch = patch;

    pdisp->destroyDisplay = driDestroyDisplay;

    /* allocate array of pointers to createNewScreen funcs */
    pdisp->createNewScreen = (PFNCREATENEWSCREENFUNC *)
      Xmalloc(numScreens * sizeof(void *));
    if (!pdisp->createNewScreen) {
       Xfree(pdpyp);
       return NULL;
    }

    /* allocate array of library handles */
    pdpyp->libraryHandles = (void **) Xmalloc(numScreens * sizeof(void*));
    if (!pdpyp->libraryHandles) {
       Xfree(pdisp->createNewScreen);
       Xfree(pdpyp);
       return NULL;
    }

    /* dynamically discover DRI drivers for all screens, saving each
     * driver's "__driCreateScreen" function pointer.  That's the bootstrap
     * entrypoint for all DRI drivers.
     */
    for (scrn = 0; scrn < numScreens; scrn++) {
        __DRIdriver *driver = driGetDriver(dpy, scrn);
        if (driver) {
           pdisp->createNewScreen[scrn] = driver->createNewScreenFunc;
           pdpyp->libraryHandles[scrn] = driver->handle;
        }
        else {
           pdisp->createNewScreen[scrn] = NULL;
           pdpyp->libraryHandles[scrn] = NULL;
        }
    }

    return (void *)pdpyp;
}

#endif /* GLX_DIRECT_RENDERING */