patch.c

   1 /*
   2  * Copyright (C) 2010 gonzoj
   3  *
   4  * Please check the CREDITS file for further information.
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 3 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  18  */
  19
  20 #include <stdio.h>
  21 #include <stdlib.h>
  22 #include <string.h>
  23 #include <sys/mman.h>
  24 #include <unistd.h>
  25
  26 #include "d2pointers.h"
  27 #include "kernel32.h"
  28 #include "maphack.h"
  29 #include "misc.h"
  30 #include "patch.h"
  31 #include "stubs.h"
  32 #include "types.h"
  33
  34 #include "debug.h"
  35
  36 #include "version.h"
  37
  38 #define PAGE_ALIGN(addr) (addr & ~0xfff)
  39
  40 char last_game_name[512];
  41
  42 unit_any *viewing_unit;
  43
  44 #define i386_CALL 0xE8
  45 #define i386_JUMP 0xE9
  46
  47 typedef struct
  48 {
  49   unsigned char type;
  50   const char *module;
  51   vaddr offset;
  52   size_t size;
  53   void *func;
  54   unsigned char *backup;
  55 } hook;
  56
  57 #define N_HOOKS 8
  58
  59 hook
  60     hooks[] =
  61       {
  62
  63 #ifdef _VERSION_1_13 /* updated */
  64             { i386_CALL, "D2Client.dll", 0x626FE, 5, draw_automap, NULL}, /* updated 0x6FB126FE */
  65             { i386_JUMP, "D2Client.dll", 0xC3DB4, 6, draw_ingame_STUB, NULL}, /* updated 0x6FB73DB4 */
  66             { i386_CALL, "D2Client.dll", 0x92366, 6, item_name_patch_STUB, NULL}, /* updated 0x6FB42366 */
  67             { i386_CALL, "D2Multi.dll", 0x14D29, 5, next_game_name_patch, NULL}, /* updated 0x6F9E4D29 */
  68             { i386_CALL, "D2Multi.dll", 0x14A0B, 5, next_game_name_patch, NULL}, /* updated 0x6F9E4A0B */
  69             { i386_CALL, "D2Client.dll", 0x953E2, 6, view_inventory_patch_1, NULL}, /* updated 0x6FB453E2 */
  70             { i386_CALL, "D2Client.dll", 0x94AB4, 6, view_inventory_patch_2, NULL}, /* updated 0x6FB44AB4 */
  71             { i386_CALL, "D2Client.dll", 0x93A6F, 5, view_inventory_patch_3, NULL} /* updated 0x6FB43A6F */
  72
  73 #elif defined _VERSION_1_12 /* from McGod's mMap (modified) */
  74             { i386_CALL, "D2Client.dll", 0x4063E, 5, draw_automap, NULL },
  75             { i386_JUMP, "D2Client.dll", 0x90524, 6, draw_ingame_STUB, NULL },
  76             { i386_CALL, "D2Client.dll", 0xAF242, 6, view_inventory_patch_1, NULL },
  77             { i386_CALL, "D2Client.dll", 0xAE914, 6, view_inventory_patch_2, NULL },
  78             { i386_CALL, "D2Client.dll", 0xAD93F, 5, view_inventory_patch_3, NULL },
  79             { i386_CALL, "D2Client.dll", 0xAC236, 6, item_name_patch_STUB, NULL },
  80             { i386_CALL, "D2Multi.dll", 0x14959, 5, next_game_name_patch, NULL },
  81             { i386_CALL, "D2Multi.dll", 0x1463B, 5, next_game_name_patch, NULL }
  82
  83 #else
  84
  85 #error NO VERSION SPECIFIED
  86
  87 #endif
  88
  89     };
  90
  91 void
  92 draw_automap()
  93 {
  94   reveal_automap();
  95   draw_monsters();
  96   draw_automap_text();
  97   if (strlen(D2CLIENT_get_game_info()->game_ip) > 0)
  98     {
  99       draw_text(780, 122, D2FONT_GOLD, 0, D2FONT_SPECIAL, 0, "%s",
 100           D2CLIENT_get_game_info()->game_ip);
 101     }
 102 }
 103
 104 void
 105 draw_ingame()
 106 {
 107   draw_text(400, 540, D2FONT_WHITE, 0, D2FONT_STANDARD, 1, "%s",
 108       "snoogans.so v 0.4");
 109 }
 110
 111 void __attribute__((fastcall))
 112 item_name_patch(unit_any *item, ms_wchar_t *wname)
 113 {
 114   if (!item || !wname)
 115     {
 116       return;
 117     }
 118   char tmp[512];
 119   ms_wchar_to_char(wname, tmp);
 120   char line1[512], *line2;
 121   strcpy(line1, strtok(tmp, "\n"));
 122   line2 = strtok(NULL, "\n");
 123   int sockets = D2COMMON_get_unit_stat(item, 194, 0);
 124   if (sockets > 0)
 125     {
 126       char c_sockets[5];
 127       sprintf(c_sockets, " (%i)", sockets);
 128       strcat(line1, c_sockets);
 129     }
 130   if (item->item_data->flags & 0x400000)
 131     {
 132       char eth[] = " (Eth)";
 133       strcat(line1, eth);
 134     }
 135   char name[1024];
 136   sprintf(name, "(%i) ", item->item_data->level);
 137   strcat(name, line1);
 138   if (line2)
 139     {
 140       strcat(name, "\n");
 141       strcat(name, line2);
 142     }
 143   char_to_ms_wchar(name, wname);
 144 }
 145
 146 void __attribute__((fastcall))
 147 next_game_name_patch(vaddr box, int __attribute__((stdcall))
 148 (*call_back)(vaddr, DWORD, DWORD))
 149 {
 150   if (strlen(last_game_name) == 0)
 151     {
 152       return;
 153     }
 154   ms_wchar_t wname[512];
 155   char_to_ms_wchar(last_game_name, wname);
 156   D2WIN_set_control_text(box, wname);
 157   D2WIN_select_edit_box_text(box, wname);
 158   D2WIN_set_edit_box_proc(box, call_back);
 159 }
 160
 161 unit_any *
 162 get_view_unit()
 163 {
 164   if (!viewing_unit)
 165     {
 166       return D2CLIENT_get_player_unit();
 167     }
 168   return viewing_unit;
 169 }
 170
 171 unit_any *
 172 view_inventory_patch()
 173 {
 174   unit_any *unit = get_view_unit();
 175   unit_any *me = D2CLIENT_get_player_unit();
 176   if (unit->id == me->id)
 177     {
 178       return me;
 179     }
 180   draw_text(560, 300, D2FONT_WHITE, 0, D2FONT_SPECIAL, 1, "%s",
 181       unit->player_data->name);
 182   return get_view_unit();
 183 }
 184
 185 static int
 186 install_hook(const char *module, vaddr offset, vaddr func, size_t bytes,
 187     unsigned char inst, unsigned char **backup)
 188 {
 189   void *h = LoadLibraryA(module);
 190   if (h == NULL)
 191     {
 192       printf("err: could not get a handle for %s\n", module);
 193       return 0;
 194     }
 195   vaddr addr = (vaddr) h + offset;
 196   unsigned char hook[bytes];
 197   memset(hook, 0x90, bytes);
 198   hook[0] = inst;
 199   *(vaddr *) &hook[1] = func - (addr + 5);
 200   DEBUG_DO(printf("installing hook at 0x%08X to func (0x%08X)\n", addr, func)); DEBUG_DO(printf("ASM: ");)
 201   DEBUG_DO(inst == i386_CALL ? printf("call ") : printf("jmp ");)
 202   DEBUG_DO(printf("0x%08X\n", func - (addr + 5));)
 203   DEBUG_DO(printf("enabling write access to page(s) starting from 0x%08X\n", PAGE_ALIGN(addr));)
 204   if (mprotect((void *) PAGE_ALIGN(addr), bytes, PROT_READ | PROT_WRITE
 205       | PROT_EXEC))
 206     {
 207       printf("err: could not enable write access to page(s)\n");
 208       return 0;
 209     }
 210   *backup = (unsigned char *) malloc(bytes);
 211   memcpy((void *) *backup, (void *) addr, bytes);
 212   DEBUG_DO(printf("saved original code\n");)
 213   memcpy((void *) addr, (void *) hook, bytes);
 214   DEBUG_DO(printf("patched to:\n");
 215       int i;
 216       for (i = 0; i < bytes; i++)
 217         {
 218           printf("0x%02X\n", hook[i]);
 219         })
 220   DEBUG_DO(printf("disabling write access to page(s) starting from 0x%08X\n", PAGE_ALIGN(addr));)
 221   if (mprotect((void *) PAGE_ALIGN(addr), bytes, PROT_READ | PROT_EXEC))
 222     {
 223       printf("err: could not disable write access to page(s)\n");
 224       return 0;
 225     }
 226   DEBUG_DO(printf("done\n");)
 227   return 1;
 228 }
 229
 230 int
 231 install_hooks()
 232 {
 233   int i;
 234   for (i = 0; i < N_HOOKS; i++)
 235     {
 236       if (!install_hook(hooks[i].module, hooks[i].offset,
 237           (vaddr) hooks[i].func, hooks[i].size, hooks[i].type, &hooks[i].backup))
 238         {
 239           return 0;
 240         }
 241     }
 242   return 1;
 243 }
 244
 245 static int
 246 remove_hook(const char *module, vaddr offset, size_t bytes,
 247     unsigned char *backup)
 248 {
 249   void *h = LoadLibraryA(module);
 250   if (h == NULL)
 251     {
 252       printf("err: could not get a handle for %s\n", module);
 253       return 0;
 254     }
 255   vaddr addr = (vaddr) h + offset;
 256   DEBUG_DO(printf("enabling write access to page(s) starting from 0x%08X\n", PAGE_ALIGN(addr));)
 257   if (mprotect((void *) PAGE_ALIGN(addr), bytes, PROT_READ | PROT_WRITE
 258       | PROT_EXEC))
 259     {
 260       printf("err: could not enable write access to page(s)\n");
 261       return 0;
 262     }
 263   memcpy((void *) addr, (void *) backup, bytes);
 264   DEBUG_DO(printf("restored original code:\n");
 265       int i;
 266       for (i = 0; i < bytes; i++)
 267         {
 268           printf("0x%02X\n", backup[i]);
 269         })
 270   free(backup);
 271   DEBUG_DO(printf("disabling write access to page(s) starting from 0x%08X\n", PAGE_ALIGN(addr));)
 272   if (mprotect((void *) PAGE_ALIGN(addr), bytes, PROT_READ | PROT_EXEC))
 273     {
 274       printf("err: could not disable write access to page(s)\n");
 275       return 0;
 276     }
 277   DEBUG_DO(printf("done\n");)
 278   return 1;
 279 }
 280
 281 int
 282 remove_hooks()
 283 {
 284   int i;
 285   for (i = 0; i < N_HOOKS; i++)
 286     {
 287       if (hooks[i].backup)
 288         {
 289           if (!remove_hook(hooks[i].module, hooks[i].offset, hooks[i].size,
 290               hooks[i].backup))
 291             {
 292               return 0;
 293             }
 294         }
 295     }
 296   return 1;
 297 }