/* gtkiconcachevalidator.c

 * Copyright (C) 2007 Red Hat, Inc

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Library General Public

 * License as published by the Free Software Foundation; either

 * version 2 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Library General Public License for more details.

 *

 * You should have received a copy of the GNU Library General Public

 * License along with this library; if not, write to the

 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,

 * Boston, MA 02111-1307, USA.

 */

#include "config.h"

#include "gtkiconcachevalidator.h"

#include <glib.h>

#undef GDK_PIXBUF_DISABLE_DEPRECATED

#include <gdk-pixbuf/gdk-pixdata.h>

#define VERBOSE(x) 

#define check(name,condition) \

  if (!(condition)) \

    { \

      VERBOSE(g_print ("bad %s\n", (name))); \

      return FALSE; \

    } 

static inline gboolean 

get_uint16 (CacheInfo *info, 

            guint32    offset, 

            guint16   *value)

{

  if (offset < info->cache_size) 

    { 

      *value = GUINT16_FROM_BE(*(guint16*)(info->cache + offset)); 

      return TRUE;

    }

  else 

    { 

      *value = 0;

      return FALSE; 

    } 

}

static inline gboolean 

get_uint32 (CacheInfo *info, 

            guint32    offset, 

            guint32   *value)

{

  if (offset < info->cache_size) 

    { 

      *value = GUINT32_FROM_BE(*(guint32*)(info->cache + offset)); 

      return TRUE;

    }

  else 

    { 

      *value = 0;

      return FALSE; 

    } 

}

static gboolean 

check_version (CacheInfo *info)

{

  guint16 major, minor;

  check ("major version", get_uint16 (info, 0, &major) && major == 1);

  check ("minor version", get_uint16 (info, 2, &minor) && minor == 0);

  return TRUE;

}

static gboolean 

check_string (CacheInfo *info, 

              guint32    offset)

{

  check ("string offset", offset < info->cache_size);

  if (info->flags & CHECK_STRINGS) 

    {

      gint i;

      gchar c;

      /* assume no string is longer than 1k */

      for (i = 0; i < 1024; i++) 

        { 

          check ("string offset", offset + i < info->cache_size)

          c = *(info->cache + offset + i);

          if (c == '\0')

            break;

          check ("string content", g_ascii_isgraph (c));

        }

      check ("string length", i < 1024);

    }

  return TRUE;

}

static gboolean 

check_string_utf8 (CacheInfo *info, 

                   guint32    offset)

{

  check ("string offset", offset < info->cache_size);

  if (info->flags & CHECK_STRINGS) 

    {

      gint i;

      gchar c;

      /* assume no string is longer than 1k */

      for (i = 0; i < 1024; i++) 

        { 

          check ("string offset", offset + i < info->cache_size)

            c = *(info->cache + offset + i);

          if (c == '\0')

            break;

        }

      check ("string length", i < 1024);

      check ("string utf8 data", g_utf8_validate((char *)(info->cache + offset), -1, NULL));

    }

  return TRUE;

}

static gboolean 

check_directory_list (CacheInfo *info, 

                      guint32    offset)

{

  guint32 directory_offset;

  gint i;

  check ("offset, directory list", get_uint32 (info, offset, &info->n_directories));

  for (i = 0; i < info->n_directories; i++) 

    {

      check ("offset, directory", get_uint32 (info, offset + 4 + 4 * i, &directory_offset));

      if (!check_string (info, directory_offset))

        return FALSE;

    }

  return TRUE;

}

static gboolean 

check_pixel_data (CacheInfo *info, 

                  guint32    offset)

{

  guint32 type;

  guint32 length;

  check ("offset, pixel data type", get_uint32 (info, offset, &type));

  check ("offset, pixel data length", get_uint32 (info, offset + 4, &length));

  check ("pixel data type", type == 0);

  check ("pixel data length", offset + 8 + length < info->cache_size);

  if (info->flags & CHECK_PIXBUFS) 

    {

      GdkPixdata data; 

      check ("pixel data", gdk_pixdata_deserialize (&data, length,

                                                    (const guint8*)info->cache + offset + 8, 

                                                    NULL));

    }

  return TRUE;

}

static gboolean 

check_embedded_rect (CacheInfo *info, 

                     guint32    offset)

{

  check ("embedded rect", offset + 4 < info->cache_size);

  return TRUE;

}

static gboolean 

check_attach_point_list (CacheInfo *info, 

                         guint32    offset)

{

  guint32 n_attach_points;

  check ("offset, attach point list", get_uint32 (info, offset, &n_attach_points));

  check ("attach points", offset + 4 + 4 * n_attach_points < info->cache_size); 

  return TRUE;

}

static gboolean 

check_display_name_list (CacheInfo *info, 

                         guint32    offset)

{

  guint32 n_display_names, ofs;

  gint i;

  check ("offset, display name list", 

         get_uint32 (info, offset, &n_display_names));

  for (i = 0; i < n_display_names; i++) 

    {

      get_uint32(info, offset + 4 + 8 * i, &ofs;;

      if (!check_string (info, ofs))

        return FALSE;

      get_uint32(info, offset + 4 + 8 * i + 4, &ofs;;

      if (!check_string_utf8 (info, ofs))

        return FALSE;

    }

  return TRUE;	

}

static gboolean 

check_meta_data (CacheInfo *info, 

                 guint32    offset)

{

  guint32 embedded_rect_offset;

  guint32 attach_point_list_offset;

  guint32 display_name_list_offset;

  check ("offset, embedded rect", 

         get_uint32 (info, offset, &embedded_rect_offset));

  check ("offset, attach point list", 

         get_uint32 (info, offset + 4, &attach_point_list_offset));

  check ("offset, display name list", 

         get_uint32 (info, offset + 8, &display_name_list_offset));

  if (embedded_rect_offset != 0) 

    {

      if (!check_embedded_rect (info, embedded_rect_offset))

        return FALSE;

    }

  if (attach_point_list_offset != 0) 

    {

      if (!check_attach_point_list (info, attach_point_list_offset))

        return FALSE;

    }

  if (display_name_list_offset != 0) 

    {

      if (!check_display_name_list (info, display_name_list_offset))

        return FALSE;

    }

  return TRUE;

}

static gboolean 

check_image_data (CacheInfo *info, 

                  guint32    offset)

{

  guint32 pixel_data_offset;

  guint32 meta_data_offset;

  check ("offset, pixel data", get_uint32 (info, offset, &pixel_data_offset));

  check ("offset, meta data", get_uint32 (info, offset + 4, &meta_data_offset));

  if (pixel_data_offset != 0) 

    {

      if (!check_pixel_data (info, pixel_data_offset))

        return FALSE;

    }

  if (meta_data_offset != 0) 

    {

      if (!check_meta_data (info, meta_data_offset))

        return FALSE;

    }

  return TRUE;

}

static gboolean 

check_image (CacheInfo *info, 

             guint32    offset)

{

  guint16 index;

  guint16 flags;

  guint32 image_data_offset;

  check ("offset, image index", get_uint16 (info, offset, &index));

  check ("offset, image flags", get_uint16 (info, offset + 2, &flags));	

  check ("offset, image data offset", 

         get_uint32 (info, offset + 4, &image_data_offset));

  check ("image index", index < info->n_directories);

  check ("image flags", flags < 16);

  if (image_data_offset != 0) 

    {

      if (!check_image_data (info, image_data_offset))

        return FALSE;

    }

  return TRUE;

}

static gboolean 

check_image_list (CacheInfo *info, 

                  guint32    offset)

{

  guint32 n_images;

  gint i;

  check ("offset, image list", get_uint32 (info, offset, &n_images));

  for (i = 0; i < n_images; i++) 

    {

      if (!check_image (info, offset + 4 + 8 * i))

        return FALSE;

    }

  return TRUE;

}

static gboolean 

check_icon (CacheInfo *info, 

            guint32    offset)

{

  guint32 chain_offset;

  guint32 name_offset;

  guint32 image_list_offset;

  check ("offset, icon chain", get_uint32 (info, offset, &chain_offset));

  check ("offset, icon name", get_uint32 (info, offset + 4, &name_offset));

  check ("offset, icon image list", get_uint32 (info, offset + 8, 

         &image_list_offset));

  if (!check_string (info, name_offset))

    return FALSE;

  if (!check_image_list (info, image_list_offset))

    return FALSE;

  if (chain_offset != 0xffffffff) 

    {

      if (!check_icon (info, chain_offset))

        return FALSE;

    }

  return TRUE;

}

static gboolean 

check_hash (CacheInfo *info, 

            guint32    offset)

{

  guint32 n_buckets, icon_offset;

  gint i;

  check ("offset, hash size", get_uint32 (info, offset, &n_buckets));

  for (i = 0; i < n_buckets; i++) 

    {

      check ("offset, hash chain", 

             get_uint32 (info, offset + 4 + 4 * i, &icon_offset));

      if (icon_offset != 0xffffffff) 

        {

          if (!check_icon (info, icon_offset))

            return FALSE;

        }

    }

  return TRUE;

}

/**

 * _gtk_icon_cache_validate:

 * @info: a CacheInfo structure 

 *

 * Validates the icon cache passed in the @cache and

 * @cache_size fields of the @info structure. The

 * validator checks that offsets specified in the

 * cache do not point outside the mapped area, that

 * strings look reasonable, and that pixbufs can

 * be deserialized. The amount of validation can

 * be controlled with the @flags field.  

 *

 * Return value: %TRUE if the cache is valid

 */

gboolean 

_gtk_icon_cache_validate (CacheInfo *info)

{

  guint32 hash_offset;

  guint32 directory_list_offset;

  if (!check_version (info))

    return FALSE;

  check ("header, hash offset", get_uint32 (info, 4, &hash_offset));

  check ("header, directory list offset", get_uint32 (info, 8, &directory_list_offset));

  if (!check_directory_list (info, directory_list_offset))

    return FALSE;

  if (!check_hash (info, hash_offset))

    return FALSE;

  return TRUE;

}