NSIS/Source/util.cpp

/*
 * util.cpp
 * 
 * This file is a part of NSIS.
 * 
 * Copyright (C) 1999-2007 Nullsoft and Contributors
 * 
 * Licensed under the zlib/libpng license (the "License");
 * you may not use this file except in compliance with the License.
 * 
 * Licence details can be found in the file COPYING.
 * 
 * This software is provided 'as-is', without any express or implied
 * warranty.
 */

#include "Platform.h"
#include <stdio.h>
#include <stdarg.h>
#include <time.h>
#include <string.h>
#include "exehead/fileform.h"
#include "util.h"
#include "strlist.h"
#include "winchar.h"

#ifndef _WIN32
#  include <ctype.h>
#  include <unistd.h> // for close(2)
#  include <fcntl.h> // for open(2)
#  include <iconv.h>
#endif

#ifdef __APPLE__
namespace Apple { // defines struct section
#  include <mach-o/dyld.h> // for _NSGetExecutablePath
};
#  include <sys/param.h> // for MAXPATHLEN
#endif

#include <cassert> // for assert
#include <algorithm>
#include <stdexcept>

using namespace std;

int g_dopause=0;
extern int g_display_errors;
extern FILE *g_output;

void dopause(void)
{
  if (g_dopause)
  {
    if (g_display_errors) fprintf(g_output,"MakeNSIS done - hit enter to close...");
    fflush(stdout);
    int a;
    while ((a=getchar()) != '\r' && a != '\n' && a != 27/*esc*/);
  }
}

// Returns 0 if everything is OK
// Returns -1 if can't find the file
// Returns -2 if the file is an invalid bitmap
// Returns -3 if the size doesn't match
// Returns -4 if the bpp doesn't match
int update_bitmap(CResourceEditor* re, WORD id, const char* filename, int width/*=0*/, int height/*=0*/, int maxbpp/*=0*/) {
  FILE *f = FOPEN(filename, "rb");
  if (!f) return -1;

  if (fgetc(f) != 'B' || fgetc(f) != 'M') {
    fclose(f);
    return -2;
  }

  if (width != 0) {
    LONG biWidth;
    fseek(f, 18, SEEK_SET); // Seek to the width member of the header
    fread(&biWidth, sizeof(LONG), 1, f);
    FIX_ENDIAN_INT32_INPLACE(biWidth);
    if (width != biWidth) {
      fclose(f);
      return -3;
    }
  }

  if (height != 0) {
    LONG biHeight;
    fseek(f, 22, SEEK_SET); // Seek to the height member of the header
    fread(&biHeight, sizeof(LONG), 1, f);
    FIX_ENDIAN_INT32_INPLACE(biHeight);
    // Bitmap height can be negative too...
    if (height != abs(biHeight)) {
      fclose(f);
      return -3;
    }
  }

  if (maxbpp != 0) {
    WORD biBitCount;
    fseek(f, 28, SEEK_SET); // Seek to the height member of the header
    fread(&biBitCount, sizeof(WORD), 1, f);
    FIX_ENDIAN_INT16_INPLACE(biBitCount);
    if (biBitCount > maxbpp) {
      fclose(f);
      return -4;
    }
  }

  DWORD dwSize;
  fseek(f, 2, SEEK_SET);
  fread(&dwSize, sizeof(DWORD), 1, f);
  FIX_ENDIAN_INT32_INPLACE(dwSize);
  dwSize -= 14;

  unsigned char* bitmap = (unsigned char*)malloc(dwSize);
  if (!bitmap) throw bad_alloc();

  fseek(f, 14, SEEK_SET);
  if (fread(bitmap, 1, dwSize, f) != dwSize) {
    fclose(f);
    return -2;
  }
  fclose(f);

  re->UpdateResourceA(RT_BITMAP, MAKEINTRESOURCE(id), NSIS_DEFAULT_LANG, bitmap, dwSize);

  free(bitmap);

  return 0;
}

// Added by Amir Szekely 8th July 2002
// Icon editing structures
typedef struct {
  WORD wReserved;
  WORD wIsIcon;
  WORD wCount;
} IconGroupHeader;

typedef struct {
  BYTE bWidth;
  BYTE bHeight;
  BYTE bPaletteEntries;
  BYTE bReserved;
  WORD wPlanes;
  WORD wBitsPerPixel;
  DWORD dwRawSize;
  DWORD dwImageOffset;
} FileIconGroupEntry;

typedef struct {
  BYTE bWidth;
  BYTE bHeight;
  BYTE bPaletteEntries;
  BYTE bReserved;
  WORD wPlanes;
  WORD wBitsPerPixel;
  DWORD dwRawSize;
  WORD wRsrcId;
} RsrcIconGroupEntry;

#define SIZEOF_RSRC_ICON_GROUP_ENTRY 14

static FILE * open_icon(const char* filename, IconGroupHeader *igh)
{
  FILE* f = FOPEN(filename, "rb");
  if (!f)
    throw runtime_error("can't open file");

  if (!fread(igh, sizeof(IconGroupHeader), 1, f))
    throw runtime_error("unable to read file");

  FIX_ENDIAN_INT16_INPLACE(igh->wIsIcon);
  FIX_ENDIAN_INT16_INPLACE(igh->wReserved);
  FIX_ENDIAN_INT16_INPLACE(igh->wCount);

  if (igh->wIsIcon != 1 || igh->wReserved != 0)
    throw runtime_error("invalid icon file");

  return f;
}

// replace_icon, must get an initialized resource editor
void replace_icon(CResourceEditor* re, WORD wIconId, const char* filename)
{
  IconGroupHeader igh, *new_igh;
  FILE *f = open_icon(filename, &igh);

  BYTE* rsrcIconGroup = (BYTE*)malloc(sizeof(IconGroupHeader) + igh.wCount*SIZEOF_RSRC_ICON_GROUP_ENTRY);
  if (!rsrcIconGroup) throw bad_alloc();

  CopyMemory(rsrcIconGroup, &igh, sizeof(IconGroupHeader));

  new_igh = (IconGroupHeader *) rsrcIconGroup;
  FIX_ENDIAN_INT16_INPLACE(new_igh->wIsIcon);
  FIX_ENDIAN_INT16_INPLACE(new_igh->wReserved);
  FIX_ENDIAN_INT16_INPLACE(new_igh->wCount);

  RsrcIconGroupEntry* ige = (RsrcIconGroupEntry*)(rsrcIconGroup + sizeof(IconGroupHeader));

  int i = 1;

  // Delete old icons
  while (re->UpdateResourceA(RT_ICON, MAKEINTRESOURCE(i++), NSIS_DEFAULT_LANG, 0, 0));

  for (i = 0; i < igh.wCount; i++) {
    fread(ige, sizeof(FileIconGroupEntry)-sizeof(DWORD), 1, f);

    DWORD dwRawSize = FIX_ENDIAN_INT32(ige->dwRawSize);

    ige->wRsrcId = FIX_ENDIAN_INT16(i + 1);

    DWORD dwOffset;
    fread(&dwOffset, sizeof(DWORD), 1, f);

    FIX_ENDIAN_INT32_INPLACE(dwOffset);

    fpos_t pos;
    fgetpos(f, &pos);

    if (fseek(f, dwOffset, SEEK_SET)) {
      free(rsrcIconGroup);
      throw runtime_error("corrupted icon file, too small");
    }
    BYTE* iconData = (BYTE*)malloc(dwRawSize);
    if (!iconData) {
      free(rsrcIconGroup);
      throw bad_alloc();
    }
    fread(iconData, sizeof(BYTE), dwRawSize, f);
    re->UpdateResourceA(RT_ICON, MAKEINTRESOURCE(i+1), NSIS_DEFAULT_LANG, iconData, dwRawSize);
    free(iconData);

    fsetpos(f, &pos);

    // Seems like the compiler refuses to increase the pointer by just 14.
    // If you'll replace this line by ige++ you will get unwanted results.
    ige = (RsrcIconGroupEntry*)((BYTE*)ige + SIZEOF_RSRC_ICON_GROUP_ENTRY);
  }

  fclose(f);

  re->UpdateResourceA(RT_GROUP_ICON, MAKEINTRESOURCE(wIconId), NSIS_DEFAULT_LANG, rsrcIconGroup, sizeof(IconGroupHeader) + igh.wCount*SIZEOF_RSRC_ICON_GROUP_ENTRY);

  free(rsrcIconGroup);
}

#ifdef NSIS_CONFIG_UNINSTALL_SUPPORT
// returns the data of the uninstaller icon that should replace the installer icon data
unsigned char* generate_uninstall_icon_data(const char* filename, size_t &size)
{
  int i;

  IconGroupHeader igh;
  FILE *f = open_icon(filename, &igh);

  int iNewIconSize = 0;
  FileIconGroupEntry ige;

  DWORD* offsets = (DWORD*)malloc(sizeof(DWORD)*igh.wCount);
  DWORD* rawSizes = (DWORD*)malloc(sizeof(DWORD)*igh.wCount);
  if (!offsets || !rawSizes) throw bad_alloc();

  for (i = 0; i < igh.wCount; i++) {
    if (!fread(&ige, sizeof(FileIconGroupEntry), 1, f)) throw runtime_error("unable to read file");
    offsets[i] = ige.dwImageOffset;
    rawSizes[i] = ige.dwRawSize;
    iNewIconSize += FIX_ENDIAN_INT32(ige.dwRawSize);
  }

  // Before each icon come two DWORDs, one for size and the other for offset (set later)
  // The last size is 0, no offset
  iNewIconSize += sizeof(DWORD)*(1 + igh.wCount*2);

  BYTE* pbUninstIcon = (BYTE*)malloc(iNewIconSize);
  if (!pbUninstIcon) throw bad_alloc();

  BYTE* seeker = pbUninstIcon;

  for (i = 0; i < igh.wCount; i++) {
    *(DWORD*)seeker = rawSizes[i];
    seeker += sizeof(DWORD);
    *(DWORD*)seeker = 0;
    seeker += sizeof(DWORD);
    fseek(f, FIX_ENDIAN_INT32(offsets[i]), SEEK_SET);
    fread(seeker, 1, FIX_ENDIAN_INT32(rawSizes[i]), f);
    seeker += FIX_ENDIAN_INT32(rawSizes[i]);
  }

  // This is how we know there are no more icons (size = 0)
  *(DWORD*)seeker = 0;

  free(offsets);
  free(rawSizes);

  size = iNewIconSize;

  return pbUninstIcon;
}

// Added by Amir Szekely 11th July 2002
#define MY_ASSERT(x, y) if (x) {if (g_display_errors) fprintf(g_output,"\nError finding icon resources: %s -- failing!\n", y);return 0;}

int find_in_dir(PRESOURCE_DIRECTORY rd, WORD id) {
  WORD i = FIX_ENDIAN_INT16(rd->Header.NumberOfNamedEntries);
  WORD l = i + FIX_ENDIAN_INT16(rd->Header.NumberOfIdEntries);

  for (; i < l; i++) {
    if (FIX_ENDIAN_INT16(rd->Entries[i].Id) == id) {
      return i;
    }
  }

  return -1;
}

// Fill the array of icons for uninstall with their offsets
// Returns zero on failure
int generate_unicons_offsets(unsigned char* exeHeader, size_t exeHeaderSize, unsigned char* uninstIconData) {
  DWORD dwResourceSectionVA;

  PIMAGE_NT_HEADERS ntHeaders = CResourceEditor::GetNTHeaders(exeHeader);
  PRESOURCE_DIRECTORY rdRoot = CResourceEditor::GetResourceDirectory(exeHeader, exeHeaderSize, ntHeaders, &dwResourceSectionVA);

  int idx = find_in_dir(rdRoot, (WORD) (long) RT_ICON);
  MY_ASSERT(idx < 0, "no icons found");
  MY_IMAGE_RESOURCE_DIRECTORY_ENTRY rdEntry = rdRoot->Entries[idx];
  FIX_ENDIAN_INT32_INPLACE(rdEntry.OffsetToData);
  MY_ASSERT(!rdEntry.DirectoryOffset.DataIsDirectory, "bad resource directory");

  PRESOURCE_DIRECTORY rdIcons = PRESOURCE_DIRECTORY(rdEntry.DirectoryOffset.OffsetToDirectory + DWORD(rdRoot));

  MY_ASSERT((size_t)rdIcons - (size_t)exeHeader > exeHeaderSize, "corrupted EXE - invalid pointer");

  WORD wNumberOfEntries = FIX_ENDIAN_INT16(rdIcons->Header.NumberOfIdEntries);

  MY_ASSERT(wNumberOfEntries == 0, "no icons found");

  for (WORD i = 0; i < wNumberOfEntries; i++) { // Icons dir can't have named entries
    MY_IMAGE_RESOURCE_DIRECTORY_ENTRY icoEntry = rdIcons->Entries[i];
    FIX_ENDIAN_INT32_INPLACE(icoEntry.OffsetToData);

    MY_ASSERT(!icoEntry.DirectoryOffset.DataIsDirectory, "bad resource directory");
    PRESOURCE_DIRECTORY rd = PRESOURCE_DIRECTORY(icoEntry.DirectoryOffset.OffsetToDirectory + DWORD(rdRoot));
    
    MY_ASSERT((size_t)rd - (size_t)exeHeader > exeHeaderSize, "corrupted EXE - invalid pointer");

    MY_IMAGE_RESOURCE_DIRECTORY_ENTRY datEntry = rd->Entries[0];
    FIX_ENDIAN_INT32_INPLACE(datEntry.OffsetToData);

    MY_ASSERT(datEntry.DirectoryOffset.DataIsDirectory, "bad resource directory");
    
    PIMAGE_RESOURCE_DATA_ENTRY rde = PIMAGE_RESOURCE_DATA_ENTRY(datEntry.OffsetToData + DWORD(rdRoot));

    MY_ASSERT((size_t)rde - (size_t)exeHeader > exeHeaderSize, "corrupted EXE - invalid pointer");

    // find icon to replace
    LPBYTE seeker = uninstIconData;
    while (*seeker) {
      DWORD dwSize = *(DWORD*)seeker;
      seeker += sizeof(DWORD);
      DWORD dwOffset = *(DWORD*)seeker;
      // if we haven't set the offset yet and the size is the same, it's a match
      if (!dwOffset && dwSize == rde->Size)
        break;

      seeker += FIX_ENDIAN_INT32(dwSize) + sizeof(DWORD);

      // reached the end of the list and no match
      MY_ASSERT(!*seeker, "installer, uninstaller icon size mismatch - see the Icon instruction's documentation for more information");
    }

    // Set offset
    DWORD dwOffset = FIX_ENDIAN_INT32(rde->OffsetToData) + DWORD(rdRoot) - dwResourceSectionVA - DWORD(exeHeader);
    *(LPDWORD) seeker = FIX_ENDIAN_INT32(dwOffset);

    MY_ASSERT(dwOffset > exeHeaderSize || dwOffset < (DWORD)rdRoot - (DWORD)exeHeader, "invalid data offset - icon resource probably compressed");
  }

  LPBYTE seeker = uninstIconData;
  while (*seeker) {
    DWORD dwSize = *(DWORD*)seeker;
    seeker += sizeof(DWORD);
    DWORD dwOffset = *(DWORD*)seeker;
    seeker += sizeof(DWORD);
    // offset isn't set which means we found no match for this one
    MY_ASSERT(!dwOffset, "installer, uninstaller number of icons doesn't match - see the Icon instruction's documentation for more information");
    seeker += FIX_ENDIAN_INT32(dwSize);
  }

  return 1;
}
#endif // NSIS_CONFIG_UNINSTALL_SUPPORT

#ifndef _WIN32
char *CharPrev(const char *s, const char *p) {
  if (!s || !p || p < s)
    return NULL;
  while (*s) {
    char *n = CharNext(s);
    if (n >= p)
      break;
    s = n;
  }
  return (char *) s;
}

char *CharNext(const char *s) {
  int l = 0;
  if (s && *s)
    l = max(1, mblen(s, MB_CUR_MAX));
  return (char *) s + l;
}

char *CharNextExA(WORD codepage, const char *s, int flags) {
  char buf[1024];
  snprintf(buf, 1024, "CP%d", codepage);
  setlocale(LC_CTYPE, buf);

  const char* np;
  int len = mblen(s, strlen(s));
  if (len > 0)
    np = s + len;
  else
    np = s + 1;

  setlocale(LC_CTYPE, "");

  return (char *) np;
}

int wsprintf(char *s, const char *format, ...) {
  va_list val;
  va_start(val, format);
  int res = vsnprintf(s, 1024, format, val);
  va_end(val);
  return res;
}

// iconv const inconsistency workaround by Alexandre Oliva
template <typename T>
inline size_t __iconv_adaptor
  (size_t (*iconv_func)(iconv_t, T, size_t *, char**,size_t*),
  iconv_t cd, char **inbuf, size_t *inbytesleft,
  char **outbuf, size_t *outbytesleft)
{
  return iconv_func (cd, (T)inbuf, inbytesleft, outbuf, outbytesleft);
}

void static create_code_page_string(char *buf, size_t len, UINT code_page) {
  if (code_page == CP_ACP)
    code_page = 1252;

  snprintf(buf, len, "CP%d", code_page);
}

int WideCharToMultiByte(UINT CodePage, DWORD dwFlags, LPCWSTR lpWideCharStr,
    int cchWideChar, LPSTR lpMultiByteStr, int cbMultiByte, LPCSTR lpDefaultChar,
    LPBOOL lpUsedDefaultChar) {
  static char buffer[4096];

  char cp[128];
  create_code_page_string(cp, sizeof(cp), CodePage);

  iconv_t cd = iconv_open(cp, "UCS-2LE");
  if (cd == (iconv_t) -1) {
    return 0;
  }

  if (cchWideChar < 0) {
    cchWideChar = (int) winchar_strlen(lpWideCharStr) + 1;
  }

  if (cbMultiByte == 0) {
    cbMultiByte = sizeof(buffer);
    lpMultiByteStr = buffer;
  }

  char *in = (char *) lpWideCharStr;
  char *out = lpMultiByteStr;
  size_t inbytes = cchWideChar * sizeof(WCHAR);
  size_t outbytes = cbMultiByte;

  if (__iconv_adaptor(iconv, cd, &in, &inbytes, &out, &outbytes) == (size_t) -1) {
    iconv_close(cd);
    return 0;
  }

  iconv_close(cd);

  return cbMultiByte - outbytes;
}

int MultiByteToWideChar(UINT CodePage, DWORD dwFlags, LPCSTR lpMultiByteStr,
    int cbMultiByte, LPWSTR lpWideCharStr, int cchWideChar) {
  static WCHAR buffer[4096];

  char cp[128];
  create_code_page_string(cp, sizeof(cp), CodePage);

  iconv_t cd = iconv_open("UCS-2LE", cp);
  if (cd == (iconv_t) -1) {
    return 0;
  }

  if (cbMultiByte < 0) {
    cbMultiByte = strlen(lpMultiByteStr) + 1;
  }

  if (cchWideChar == 0) {
    cchWideChar = sizeof(buffer);
    lpWideCharStr = buffer;
  }

  char *in = (char *) lpMultiByteStr;
  char *out = (char *) lpWideCharStr;
  size_t inbytes = cbMultiByte;
  size_t outbytes = cchWideChar * sizeof(WCHAR);

  if (__iconv_adaptor(iconv, cd, &in, &inbytes, &out, &outbytes) == (size_t) -1) {
    iconv_close(cd);
    return 0;
  }

  iconv_close(cd);

  return cchWideChar - (outbytes / sizeof (WCHAR));
}

#define MY_ERROR_MSG(x) {if (g_display_errors) {fprintf(g_output,"%s", x);}}

char *my_convert(const char *path)
{
  // TODO: (orip) ref. this func. to use std::string?
  char *converted_path = strdup(path);
  size_t len = strlen(path);

  if(!converted_path)
  {
    MY_ERROR_MSG("Error: could not allocate memory in my_convert()\n");
    return (char*) path; /* dirty */
  }

  /* Replace drive letter X: by /X */
  if(len >= 2)
  {
    if (path[1] == ':')
    {
      converted_path[0] = '/';
      converted_path[1] = (char) tolower((int) path[0]);
    }
  }

  char *p = converted_path;

  do
  {
    if (*p == '\\')
    {
      *p = '/';
    }
    p = CharNext(p);
  }
  while (*p);

  return converted_path;
}

void my_convert_free(char *converted_path)
{
  free(converted_path);
}

int my_open(const char *pathname, int flags)
{
  char *converted_pathname = my_convert(pathname);

  int result = open(converted_pathname, flags);
  my_convert_free(converted_pathname);
  return result;
}

FILE *my_fopen(const char *path, const char *mode)
{
  char *converted_path = my_convert(path);

  FILE *result = fopen(converted_path, mode);
  my_convert_free(converted_path);
  return result;
}
#endif//!_WIN32

void *operator new(size_t size) {
  void *p = malloc(size);
  if (!p)
    throw bad_alloc();
  return p;
}

void operator delete(void *p) {
  if (p) free(p);
}

void operator delete [](void *p) {
  if (p) free(p);
}

size_t my_strftime(char *s, size_t max, const char  *fmt, const struct tm *tm) {
  return strftime(s, max, fmt, tm);
}

string get_full_path(const string &path) {
#ifdef _WIN32
  char *throwaway;
  char real_path[1024];
  int rc = GetFullPathName(path.c_str(),1024,real_path,&throwaway);
  assert(rc <= 1024); // path size is limited by MAX_PATH (260)
  assert(rc != 0); // rc==0 in case of error
  return string(real_path);
#else//_WIN32
#ifdef PATH_MAX
  static char buffer[PATH_MAX];
#else//PATH_MAX
  int path_max = pathconf(path, _PC_PATH_MAX);
  if (path_max <= 0)
    path_max = 4096;
  char *buffer = (char *) malloc(path_max);
  if (!buffer)
    return string(path);
#endif//PATH_MAX
  if (!realpath(path.c_str(), buffer))
    strcpy(buffer, path.c_str());
  string result(buffer);
#ifndef PATH_MAX
  free(buffer);
#endif//!PATH_MAX
  return result;
#endif//_WIN32
}

string get_string_prefix(const string& str, const string& separator) {
  const string::size_type last_separator_pos = str.rfind(separator);
  if (last_separator_pos == string::npos)
    return str;
  return str.substr(0, last_separator_pos);
}

string get_string_suffix(const string& str, const string& separator) {
  const string::size_type last_separator_pos = str.rfind(separator);
  if (last_separator_pos == string::npos)
    return str;
  return str.substr(last_separator_pos + separator.size(), string::npos);
}

string get_dir_name(const string& path) {
  return get_string_prefix(path, PLATFORM_PATH_SEPARATOR_STR);
}

string get_file_name(const string& path) {
  return get_string_suffix(path, PLATFORM_PATH_SEPARATOR_STR);
}

string get_executable_path(const char* argv0) {
#ifdef _WIN32
  char temp_buf[MAX_PATH+1];
  temp_buf[0] = '\0';
  int rc = GetModuleFileName(NULL,temp_buf,MAX_PATH);
  assert(rc != 0);
  return string(temp_buf);
#elif __APPLE__
  char temp_buf[MAXPATHLEN+1];
  unsigned int buf_len = MAXPATHLEN;
  int rc = Apple::_NSGetExecutablePath(temp_buf, &buf_len);
  assert(rc == 0);
  return string(temp_buf);
#else /* Linux/BSD/POSIX/etc */
  const char *envpath = getenv("_");
  if( envpath != NULL ) return get_full_path( envpath );
  else {
    char* pathtmp;
    char* path = NULL;
    size_t len = 100;
    size_t nchars;
    while(1){
      pathtmp = (char*)realloc(path,len+1);
      if( pathtmp == NULL ){
        free(path);
        return get_full_path(argv0);
      }
      path = pathtmp;
      nchars = readlink("/proc/self/exe", path, len);
      if( nchars < 0 ){
        free(path);
        return get_full_path(argv0);
      }
      if( nchars < len ){
        path[nchars] = '\0';
        string result(path);
        free(path);
        return result;
      }
      len *= 2;
    }
  }
#endif
}

string get_executable_dir(const char *argv0) {
  return get_dir_name(get_executable_path(argv0));
}

string remove_file_extension(const string& path) {
  return get_string_prefix(path, ".");
}

string lowercase(const string &str) {
  string result = str;
  transform(str.begin(), str.end(), result.begin(), tolower);
  return result;
}

int sane_system(const char *command) {
#ifdef _WIN32

  // workaround for bug #1509909
  // http://sf.net/tracker/?func=detail&atid=373085&aid=1509909&group_id=22049
  //
  // cmd.exe /C has some weird handling for quotes. it strips
  // the surrounding quotes, if they exist. if there are quotes
  // around the program path and its arguments, it will strip
  // the outer quotes. this may result in something like:
  //   `program files\nsis\makensis.exe" "args`
  // which obviously fails...
  //
  // to avoid the stripping, a harmless string is prefixed
  // to the command line.

  string command_s = "IF 1==1 ";
  command_s += command;
  return system(command_s.c_str());

#else

  return system(command);

#endif
}

static bool GetDLLVersionUsingRE(const string& filepath, DWORD& high, DWORD & low)
{
  bool found = false;

  FILE *fdll = FOPEN(filepath.c_str(), "rb");
  if (!fdll)
    return 0;

  fseek(fdll, 0, SEEK_END);
  unsigned int len = ftell(fdll);
  fseek(fdll, 0, SEEK_SET);

  LPBYTE dll = (LPBYTE) malloc(len);

  if (!dll)
  {
    fclose(fdll);
    return 0;
  }

  if (fread(dll, 1, len, fdll) != len)
  {
    fclose(fdll);
    free(dll);
    return 0;
  }

  try
  {
    CResourceEditor *dllre = new CResourceEditor(dll, len);
    LPBYTE ver = dllre->GetResourceA(VS_FILE_INFO, MAKEINTRESOURCE(VS_VERSION_INFO), 0);
    int versize = dllre->GetResourceSizeA(VS_FILE_INFO, MAKEINTRESOURCE(VS_VERSION_INFO), 0);

    if (ver)
    {
      if ((size_t) versize > sizeof(WORD) * 3)
      {
        // get VS_FIXEDFILEINFO from VS_VERSIONINFO
        WCHAR *szKey = (WCHAR *)(ver + sizeof(WORD) * 3);
        int len = (winchar_strlen(szKey) + 1) * sizeof(WCHAR) + sizeof(WORD) * 3;
        len = (len + 3) & ~3; // align on DWORD boundry
        VS_FIXEDFILEINFO *verinfo = (VS_FIXEDFILEINFO *)(ver + len);
        if (versize > len && verinfo->dwSignature == VS_FFI_SIGNATURE)
        {
          low = verinfo->dwFileVersionLS;
          high = verinfo->dwFileVersionMS;
          found = true;
        }
      }
      dllre->FreeResource(ver);
    }

    delete dllre;
  }
  catch (exception&)
  {
  }

  return found;
}

static bool GetDLLVersionUsingAPI(const string& filepath, DWORD& high, DWORD& low)
{
  bool found = false;

#ifdef _WIN32
  char path[1024];
  char *name;
  path[0] = 0;

  GetFullPathName(filepath.c_str(), 1024, path, &name);

  DWORD d;
  DWORD verSize = GetFileVersionInfoSize(path, &d);
  if (verSize)
  {
    void *buf = (void *) GlobalAlloc(GPTR, verSize);
    if (buf)
    {
      UINT uLen;
      VS_FIXEDFILEINFO *pvsf;
      if (GetFileVersionInfo(path, 0, verSize, buf) && VerQueryValue(buf, "\\", (void**) &pvsf, &uLen))
      {
        low = pvsf->dwFileVersionLS;
        high = pvsf->dwFileVersionMS;
        found = true;
      }
      GlobalFree(buf);
    }
  }
#endif

  return found;
}

#ifdef _WIN32

// the following structure must be byte-aligned.
#pragma pack( push, pre_vxd_ver, 1 )
typedef struct _VXD_VERSION_RESOURCE {
  char  cType;
  WORD  wID;
  char  cName;
  WORD  wOrdinal;
  WORD  wFlags;
  DWORD dwResSize;
  BYTE  bVerData;
} VXD_VERSION_RESOURCE, *PVXD_VERSION_RESOURCE;
#pragma pack( pop, pre_vxd_ver )

static BOOL GetVxdVersion( LPCSTR szFile, LPDWORD lpdwLen, LPVOID lpData ) 
{

  HANDLE hFile        = NULL;
  HANDLE hFileMapping = NULL;
  void * pView        = NULL;
  DWORD  dwSize       = 0;
  DWORD  dwError      = 0;

  PIMAGE_DOS_HEADER       pDosExeHdr = NULL;
  PIMAGE_NT_HEADERS       pNtExeHdr  = NULL;
  PIMAGE_VXD_HEADER       pLEHdr     = NULL;
  PVXD_VERSION_RESOURCE   pVerRes    = NULL;
  LPVOID                  pRawRes    = NULL;

  // Open the file for shared read access.
  hFile = CreateFile( szFile, GENERIC_READ, FILE_SHARE_READ,
       NULL, OPEN_EXISTING, 0, NULL );
  if ( hFile == INVALID_HANDLE_VALUE )
  {
    return FALSE;
  }

  // Create a read-only file mapping object for the file.
  hFileMapping = CreateFileMapping( hFile, NULL,
       PAGE_READONLY, 0, 0, NULL);
  if ( !hFileMapping )
  {
    dwError = GetLastError();

    if ( hFile != INVALID_HANDLE_VALUE )
      CloseHandle( hFile );

    SetLastError( dwError );
    return FALSE;
  }

  // Map a view of the the file.
  pView = MapViewOfFile( hFileMapping, FILE_MAP_READ, 0, 0, 0 );
  if ( !pView )
  {
    dwError = GetLastError();

    if ( hFileMapping )
      CloseHandle( hFileMapping );

    if ( hFile != INVALID_HANDLE_VALUE )
      CloseHandle( hFile );

    SetLastError( dwError );
    return FALSE;
  }

  // The DOS header begins at byte 0.
  pDosExeHdr = (PIMAGE_DOS_HEADER) pView;

  // Check to make sure the file has a DOS EXE header.
  if ( pDosExeHdr->e_magic != IMAGE_DOS_SIGNATURE ) 
  {
    if ( pView )
      UnmapViewOfFile( pView );

    if ( hFileMapping )
      CloseHandle( hFileMapping );

    if ( hFile != INVALID_HANDLE_VALUE )
      CloseHandle( hFile );

    SetLastError( ERROR_BAD_FORMAT );
    return FALSE;
  }

  // Find the beginning of the NT header at offset e_lfanew.
  pNtExeHdr = (PIMAGE_NT_HEADERS) ( (DWORD) pView
       + (DWORD) pDosExeHdr->e_lfanew );

  // Check to make sure the file is a VxD.
  if ( (DWORD) pNtExeHdr->Signature != IMAGE_VXD_SIGNATURE ) 
  {
    if ( pView )
      UnmapViewOfFile( pView );

    if ( hFileMapping )
      CloseHandle( hFileMapping );

    if ( hFile != INVALID_HANDLE_VALUE )
      CloseHandle( hFile );

    SetLastError( ERROR_BAD_FORMAT );
    return FALSE;
  }

  // The LE header begins at the same place as the NT header.
  pLEHdr = (PIMAGE_VXD_HEADER) pNtExeHdr;

  // e32_winreslen contains the size of the VxD's version resource.
  if ( pLEHdr->e32_winreslen == 0 ) {
    *lpdwLen = 0;
    if ( pView )
      UnmapViewOfFile( pView );

    if ( hFileMapping )
      CloseHandle( hFileMapping );

    if ( hFile != INVALID_HANDLE_VALUE )
      CloseHandle( hFile );

    SetLastError( ERROR_RESOURCE_DATA_NOT_FOUND );
    return FALSE;
  }

  // e32_winresoff contains the offset of the resource in the VxD.
  pVerRes = (VXD_VERSION_RESOURCE *) ( (DWORD) pView
       + (DWORD) pLEHdr->e32_winresoff );
  dwSize = pVerRes->dwResSize;
  pRawRes = &(pVerRes->bVerData);

  // Make sure the supplied buffer is large enough for the resource.
  if ( ( lpData == NULL ) || ( *lpdwLen < dwSize ) ) {
    *lpdwLen = dwSize;

    if ( pView )
      UnmapViewOfFile( pView );

    if ( hFileMapping )
      CloseHandle( hFileMapping );

    if ( hFile != INVALID_HANDLE_VALUE )
      CloseHandle( hFile );

    SetLastError( ERROR_INSUFFICIENT_BUFFER );
    return FALSE;
  }

  // Zero the passed buffer and copy the resource into it.
  ZeroMemory( lpData, *lpdwLen );
  CopyMemory( lpData, pRawRes, dwSize );
  *lpdwLen = dwSize;

  // Clean up resources.
  if ( pView )
    UnmapViewOfFile( pView );

  if ( hFileMapping )
    CloseHandle( hFileMapping );

  if ( hFile != INVALID_HANDLE_VALUE )
    CloseHandle( hFile );

  SetLastError(0);
  return TRUE;
}

static DWORD GetVxdVersionInfoSize( LPCSTR szFile ) 
{
  DWORD dwResult = 0;

  // Call GetVxdVersion() with NULL for the pointer to the buffer.
  if ( !GetVxdVersion( szFile, &dwResult, NULL ) ) 
  {
    DWORD dwError = GetLastError();

    // GetVxdVersion() will fail with ERROR_INSUFFICIENT_BUFFER and
    // the required buffer size will be returned in dwResult.
    if ( GetLastError() == ERROR_INSUFFICIENT_BUFFER ) 
    {
      SetLastError( 0 );
      return dwResult;
    }
  }

  // The following line is never executed.
  return 0;
}

static BOOL GetVxdVersionInfo( LPCSTR szFile, DWORD dwLen, LPVOID lpData ) 
{
  return GetVxdVersion( szFile, &dwLen, lpData );
}

#endif //_WIN32

static bool GetDLLVersionFromVXD(const string& filepath, DWORD& high, DWORD& low)
{
  bool found = false;

#ifdef _WIN32
  DWORD verSize = GetVxdVersionInfoSize(filepath.c_str());
  if (verSize)
  {
    void *buf = (void *) GlobalAlloc(GPTR, verSize);
    if (buf)
    {
      UINT uLen;
      VS_FIXEDFILEINFO *pvsf;
      if (GetVxdVersionInfo(filepath.c_str(), verSize, buf) && VerQueryValue(buf, "\\", (void**) &pvsf, &uLen))
      {
        low = pvsf->dwFileVersionLS;
        high = pvsf->dwFileVersionMS;
        found = true;
      }
      GlobalFree(buf);
    }
  }
#endif

  return found;
}

bool GetDLLVersion(const string& filepath, DWORD& high, DWORD& low)
{
  if (GetDLLVersionUsingAPI(filepath, high, low))
    return true;

  if (GetDLLVersionUsingRE(filepath, high, low))
    return true;

  if (GetDLLVersionFromVXD(filepath, high, low))
    return true;

  return false;
}