boost.c

#include <stdint.h>
#include "minhook/include/MinHook.h"


typedef void(__fastcall* netcat_insert_direct_t)(uint64_t catalog, uint64_t* key, uint64_t** item);
netcat_insert_direct_t netcat_insert_direct = NULL;

typedef size_t (__cdecl* strlen_t)(const char *str);
strlen_t builtin_strlen = NULL;

HMODULE g_hmod = NULL;
HANDLE g_uninject_thread = NULL;

uint64_t netcat_insert_dedupe_addr = 0;
uint64_t strlen_addr = 0;


// proper dll self unloading - not sure where I got this from
DWORD WINAPI unload_thread(LPVOID lpThreadParameter)
{
  CloseHandle(g_uninject_thread);
  FreeLibraryAndExitThread(g_hmod, 0);
}

void unload()
{
  g_uninject_thread = CreateThread(NULL, 0, &unload_thread, NULL, 0, NULL);
}


// not-really-safe strlen
// comes with a built in "cache" for exactly one item
size_t strlen_cacher(char* str)
{
  static char* start = NULL;
  static char* end = NULL;
  size_t len = 0;
  const size_t cap = 20000;

  // if we have a "cached" string and current pointer is within it
  if (start && str >= start && str <= end) {
    // calculate the new strlen
    len = end - str;

    // if we're near the end, unload self
    // we don't want to mess something else up
    if (len < cap / 2)
      MH_DisableHook((LPVOID)strlen_addr);

    // super-fast return!
    return len;
  }

  // count the actual length
  // we need at least one measurement of the large JSON
  // or normal strlen for other strings
  len = builtin_strlen(str);

  // if it was the really long string
  // save it's start and end addresses
  if (len > cap) {
    start = str;
    end = str + len;
  }

  // slow, boring return
  return len;
}


// normally this checks for duplicates before inserting
// but to speed things up we just skip that and insert directly
char __fastcall netcat_insert_dedupe_hooked(uint64_t catalog, uint64_t* key, uint64_t* item)
{
  // didn't bother reversing the structure
  uint64_t not_a_hashmap = catalog + 88;

  // no idea what this does, but repeat what the original did
  if (!(*(uint8_t(__fastcall**)(uint64_t*))(*item + 48))(item))
    return 0;

  // insert directly
  netcat_insert_direct(not_a_hashmap, key, &item);

  // remove hooks when the last item's hash is hit
  // and unload the .dll, we are done here :)
  if (*key == 0x7FFFD6BE) {
    MH_DisableHook((LPVOID)netcat_insert_dedupe_addr);
    unload();
  }

  return 1;
}

void initialize()
{
  // set up function hooks
  uint64_t base_addr = (uint64_t)GetModuleHandleA(NULL);
  
  if (GetModuleHandleA("steam_api64.dll") == NULL) {
    // addresses hardcoded for Social Club version 2215/1.53
    netcat_insert_dedupe_addr = base_addr + 0x10A9664;
    strlen_addr = base_addr + 0x17BD600;

    netcat_insert_direct = (netcat_insert_direct_t)(base_addr + 0x24EA8C);
  } else {
    // addresses hardcoded for Steam version 2215/1.53
    netcat_insert_dedupe_addr = base_addr + 0x10AA918;
    strlen_addr = base_addr + 0x17C01A0;

    netcat_insert_direct = (netcat_insert_direct_t)(base_addr + 0x5BB07C);
  }
  
  MH_Initialize();

  MH_CreateHook((LPVOID)strlen_addr, &strlen_cacher, (LPVOID*)&builtin_strlen);
  MH_CreateHook((LPVOID)netcat_insert_dedupe_addr, &netcat_insert_dedupe_hooked, NULL);
  
  MH_EnableHook((LPVOID)strlen_addr);
  MH_EnableHook((LPVOID)netcat_insert_dedupe_addr);
}

BOOL WINAPI DllMain(HINSTANCE hinstDLL, DWORD fdwReason, LPVOID lpvReversed)
{
  switch (fdwReason)
  {
  case DLL_PROCESS_ATTACH:
    g_hmod = hinstDLL;
    initialize();

    break;
  case DLL_PROCESS_DETACH:
    MH_Uninitialize();
    break;
  }

  return TRUE;
}