/* GLIB - Library of useful routines for C programming
 * Copyright (C) 1995-1998  Peter Mattis, Spencer Kimball and Josh MacDonald
 * Copyright (C) 1998-1999  Tor Lillqvist
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
 */

/*
 * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GLib Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GLib at ftp://ftp.gtk.org/pub/gtk/. 
 */

/* 
 * MT safe for the unix part, FIXME: make the win32 part MT safe as well.
 */

#include "config.h"

#include "glibconfig.h"

#include <glib/gstdio.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <wchar.h>
#include <errno.h>
#include <fcntl.h>

#include <winsock2.h>
#include <windows.h>
#ifndef G_WITH_CYGWIN
#include <direct.h>
#endif
#include <errno.h>
#include <ctype.h>
#if defined(_MSC_VER) || defined(__DMC__)
#  include <io.h>
#endif /* _MSC_VER || __DMC__ */

#define MODERN_API_FAMILY 2

#if WINAPI_FAMILY == MODERN_API_FAMILY
/* This is for modern UI Builds, where we can't use LoadLibraryW()/GetProcAddress() */
/* ntddk.h is found in the WDK, and MinGW */
#include <ntddk.h>

#ifdef _MSC_VER
#pragma comment (lib, "ntoskrnl.lib")
#endif
#elif defined(__MINGW32__) && !defined(__MINGW64_VERSION_MAJOR)
/* mingw-w64 must use winternl.h, but not MinGW */
#include <ntdef.h>
#else
#include <winternl.h>
#endif

#include "glib.h"
#include "gwin32.h"
#include "gwin32private.h"
#include "gthreadprivate.h"
#include "gwin32private.h"
#include "glib-init.h"

#ifdef G_WITH_CYGWIN
#include <sys/cygwin.h>
#endif

#ifndef G_WITH_CYGWIN

gint
g_win32_ftruncate (gint  fd,
		   guint size)
{
  return _chsize (fd, size);
}

#endif

/**
 * g_win32_getlocale:
 *
 * The setlocale() function in the Microsoft C library uses locale
 * names of the form "English_United States.1252" etc. We want the
 * UNIXish standard form "en_US", "zh_TW" etc. This function gets the
 * current thread locale from Windows - without any encoding info -
 * and returns it as a string of the above form for use in forming
 * file names etc. The returned string should be deallocated with
 * g_free().
 *
 * Returns: newly-allocated locale name.
 **/

#ifndef SUBLANG_SERBIAN_LATIN_BA
#define SUBLANG_SERBIAN_LATIN_BA 0x06
#endif

gchar *
g_win32_getlocale (void)
{
  gchar *result;
  LCID lcid;
  LANGID langid;
  const gchar *ev;
  gint primary, sub;
  WCHAR iso639[10];
  gchar *iso639_utf8;
  WCHAR iso3166[10];
  gchar *iso3166_utf8;
  const gchar *script = NULL;

  /* Let the user override the system settings through environment
   * variables, as on POSIX systems. Note that in GTK applications
   * since GTK 2.10.7 setting either LC_ALL or LANG also sets the
   * Win32 locale and C library locale through code in gtkmain.c.
   */
  if (((ev = g_getenv ("LC_ALL")) != NULL && ev[0] != '\0')
      || ((ev = g_getenv ("LC_MESSAGES")) != NULL && ev[0] != '\0')
      || ((ev = g_getenv ("LANG")) != NULL && ev[0] != '\0'))
    return g_strdup (ev);

  lcid = GetThreadLocale ();

  if (!GetLocaleInfoW (lcid, LOCALE_SISO639LANGNAME, iso639, sizeof (iso639)) ||
      !GetLocaleInfoW (lcid, LOCALE_SISO3166CTRYNAME, iso3166, sizeof (iso3166)))
    return g_strdup ("C");
  
  /* Strip off the sorting rules, keep only the language part.  */
  langid = LANGIDFROMLCID (lcid);

  /* Split into language and territory part.  */
  primary = PRIMARYLANGID (langid);
  sub = SUBLANGID (langid);

  /* Handle special cases */
  switch (primary)
    {
    case LANG_AZERI:
      switch (sub)
	{
	case SUBLANG_AZERI_LATIN:
	  script = "@Latn";
	  break;
	case SUBLANG_AZERI_CYRILLIC:
	  script = "@Cyrl";
	  break;
	}
      break;
    case LANG_SERBIAN:		/* LANG_CROATIAN == LANG_SERBIAN */
      switch (sub)
	{
	case SUBLANG_SERBIAN_LATIN:
	case 0x06: /* Serbian (Latin) - Bosnia and Herzegovina */
	  script = "@Latn";
	  break;
	}
      break;
    case LANG_UZBEK:
      switch (sub)
	{
	case SUBLANG_UZBEK_LATIN:
	  script = "@Latn";
	  break;
	case SUBLANG_UZBEK_CYRILLIC:
	  script = "@Cyrl";
	  break;
	}
      break;
    }

  iso639_utf8 = g_utf16_to_utf8 (iso639, -1, NULL, NULL, NULL);
  iso3166_utf8 = g_utf16_to_utf8 (iso3166, -1, NULL, NULL, NULL);

  result = g_strconcat (iso639_utf8, "_", iso3166_utf8, script, NULL);

  g_free (iso3166_utf8);
  g_free (iso639_utf8);

  return result;
}

/**
 * g_win32_error_message:
 * @error: Win32 error code
 *
 * Translate a Win32 error code into a human readable message.
 *
 * The error code could be as returned by
 * [`GetLastError()`](https://learn.microsoft.com/en-us/windows/win32/api/errhandlingapi/nf-errhandlingapi-getlasterror)
 * or [`WSAGetLastError()`](https://learn.microsoft.com/en-us/windows/win32/api/winsock/nf-winsock-wsagetlasterror).
 *
 * The message is either language neutral, or in the thread’s language, or the
 * user’s language, the system’s language, or US English (see documentation for
 * [`FormatMessage()`](https://learn.microsoft.com/en-us/windows/win32/api/winbase/nf-winbase-formatmessagew)).
 * The returned string is in UTF-8.
 *
 * If a human readable message cannot be found for the given @error, an empty
 * string is returned.
 *
 * Returns: (transfer full) (not nullable): newly-allocated error message
 **/
gchar *
g_win32_error_message (gint error)
{
  gchar *retval;
  wchar_t *msg = NULL;
  size_t nchars;

  FormatMessageW (FORMAT_MESSAGE_ALLOCATE_BUFFER
		  |FORMAT_MESSAGE_IGNORE_INSERTS
		  |FORMAT_MESSAGE_FROM_SYSTEM,
		  NULL, error, 0,
		  (LPWSTR) &msg, 0, NULL);
  if (msg != NULL)
    {
      nchars = wcslen (msg);

      if (nchars >= 2 && msg[nchars-1] == L'\n' && msg[nchars-2] == L'\r')
        msg[nchars-2] = L'\0';

      retval = g_utf16_to_utf8 (msg, -1, NULL, NULL, NULL);

      LocalFree (msg);
    }
  else
    retval = g_strdup ("");

  return retval;
}

/**
 * g_win32_get_package_installation_directory_of_module:
 * @hmodule: (nullable): The Win32 handle for a DLL loaded into the current process, or %NULL
 *
 * This function tries to determine the installation directory of a
 * software package based on the location of a DLL of the software
 * package.
 *
 * @hmodule should be the handle of a loaded DLL or %NULL. The
 * function looks up the directory that DLL was loaded from. If
 * @hmodule is NULL, the directory the main executable of the current
 * process is looked up. If that directory's last component is "bin"
 * or "lib", its parent directory is returned, otherwise the directory
 * itself.
 *
 * It thus makes sense to pass only the handle to a "public" DLL of a
 * software package to this function, as such DLLs typically are known
 * to be installed in a "bin" or occasionally "lib" subfolder of the
 * installation folder. DLLs that are of the dynamically loaded module
 * or plugin variety are often located in more private locations
 * deeper down in the tree, from which it is impossible for GLib to
 * deduce the root of the package installation.
 *
 * The typical use case for this function is to have a DllMain() that
 * saves the handle for the DLL. Then when code in the DLL needs to
 * construct names of files in the installation tree it calls this
 * function passing the DLL handle.
 *
 * Returns: a string containing the guessed installation directory for
 * the software package @hmodule is from. The string is in the GLib
 * file name encoding, i.e. UTF-8. The return value should be freed
 * with g_free() when not needed any longer. If the function fails
 * %NULL is returned.
 *
 * Since: 2.16
 */
gchar *
g_win32_get_package_installation_directory_of_module (gpointer hmodule)
{
  gchar *filename;
  gchar *retval;
  gchar *p;
  wchar_t wc_fn[MAX_PATH];

  /* NOTE: it relies that GetModuleFileNameW returns only canonical paths */
  if (!GetModuleFileNameW (hmodule, wc_fn, MAX_PATH))
    return NULL;

  filename = g_utf16_to_utf8 (wc_fn, -1, NULL, NULL, NULL);

  if ((p = strrchr (filename, G_DIR_SEPARATOR)) != NULL)
    *p = '\0';

  retval = g_strdup (filename);

  do
    {
      p = strrchr (retval, G_DIR_SEPARATOR);
      if (p == NULL)
        break;

      *p = '\0';

      if (g_ascii_strcasecmp (p + 1, "bin") == 0 ||
          g_ascii_strcasecmp (p + 1, "lib") == 0)
        break;
    }
  while (p != NULL);

  if (p == NULL)
    {
      g_free (retval);
      retval = filename;
    }
  else
    g_free (filename);

#ifdef G_WITH_CYGWIN
  /* In Cygwin we need to have POSIX paths */
  {
    gchar tmp[MAX_PATH];

    cygwin_conv_to_posix_path (retval, tmp);
    g_free (retval);
    retval = g_strdup (tmp);
  }
#endif

  return retval;
}

static gchar *
get_package_directory_from_module (const gchar *module_name)
{
  static GHashTable *module_dirs = NULL;
  G_LOCK_DEFINE_STATIC (module_dirs);
  HMODULE hmodule = NULL;
  gchar *fn;

  G_LOCK (module_dirs);

  if (module_dirs == NULL)
    module_dirs = g_hash_table_new (g_str_hash, g_str_equal);
  
  fn = g_hash_table_lookup (module_dirs, module_name ? module_name : "");
      
  if (fn)
    {
      G_UNLOCK (module_dirs);
      return g_strdup (fn);
    }

  if (module_name)
    {
      wchar_t *wc_module_name = g_utf8_to_utf16 (module_name, -1, NULL, NULL, NULL);
      hmodule = GetModuleHandleW (wc_module_name);
      g_free (wc_module_name);

      if (!hmodule)
	{
	  G_UNLOCK (module_dirs);
	  return NULL;
	}
    }

  fn = g_win32_get_package_installation_directory_of_module (hmodule);

  if (fn == NULL)
    {
      G_UNLOCK (module_dirs);
      return NULL;
    }
  
  g_hash_table_insert (module_dirs, module_name ? g_strdup (module_name) : "", fn);

  G_UNLOCK (module_dirs);

  return g_strdup (fn);
}

/**
 * g_win32_get_package_installation_directory:
 * @package: (nullable): You should pass %NULL for this.
 * @dll_name: (nullable): The name of a DLL that a package provides in UTF-8, or %NULL.
 *
 * Try to determine the installation directory for a software package.
 *
 * This function is deprecated. Use
 * g_win32_get_package_installation_directory_of_module() instead.
 *
 * The use of @package is deprecated. You should always pass %NULL. A
 * warning is printed if non-NULL is passed as @package.
 *
 * The original intended use of @package was for a short identifier of
 * the package, typically the same identifier as used for
 * `GETTEXT_PACKAGE` in software configured using GNU
 * autotools. The function first looks in the Windows Registry for the
 * value `#InstallationDirectory` in the key
 * `#HKLM\Software\@package`, and if that value
 * exists and is a string, returns that.
 *
 * It is strongly recommended that packagers of GLib-using libraries
 * for Windows do not store installation paths in the Registry to be
 * used by this function as that interferes with having several
 * parallel installations of the library. Enabling multiple
 * installations of different versions of some GLib-using library, or
 * GLib itself, is desirable for various reasons.
 *
 * For this reason it is recommended to always pass %NULL as
 * @package to this function, to avoid the temptation to use the
 * Registry. In version 2.20 of GLib the @package parameter
 * will be ignored and this function won't look in the Registry at all.
 *
 * If @package is %NULL, or the above value isn't found in the
 * Registry, but @dll_name is non-%NULL, it should name a DLL loaded
 * into the current process. Typically that would be the name of the
 * DLL calling this function, looking for its installation
 * directory. The function then asks Windows what directory that DLL
 * was loaded from. If that directory's last component is "bin" or
 * "lib", the parent directory is returned, otherwise the directory
 * itself. If that DLL isn't loaded, the function proceeds as if
 * @dll_name was %NULL.
 *
 * If both @package and @dll_name are %NULL, the directory from where
 * the main executable of the process was loaded is used instead in
 * the same way as above.
 *
 * Returns: a string containing the installation directory for
 * @package. The string is in the GLib file name encoding,
 * i.e. UTF-8. The return value should be freed with g_free() when not
 * needed any longer. If the function fails %NULL is returned.
 *
 * Deprecated: 2.18: Pass the HMODULE of a DLL or EXE to
 * g_win32_get_package_installation_directory_of_module() instead.
 **/

gchar *
g_win32_get_package_installation_directory (const gchar *package,
                                            const gchar *dll_name)
{
  gchar *result = NULL;

  if (package != NULL)
      g_warning ("Passing a non-NULL package to g_win32_get_package_installation_directory() is deprecated and it is ignored.");

  if (dll_name != NULL)
    result = get_package_directory_from_module (dll_name);

  if (result == NULL)
    result = get_package_directory_from_module (NULL);

  return result;
}

/**
 * g_win32_get_package_installation_subdirectory:
 * @package: (nullable): You should pass %NULL for this.
 * @dll_name: (nullable): The name of a DLL that a package provides, in UTF-8, or %NULL.
 * @subdir: A subdirectory of the package installation directory, also in UTF-8
 *
 * This function is deprecated. Use
 * g_win32_get_package_installation_directory_of_module() and
 * g_build_filename() instead.
 *
 * Returns a newly-allocated string containing the path of the
 * subdirectory @subdir in the return value from calling
 * g_win32_get_package_installation_directory() with the @package and
 * @dll_name parameters. See the documentation for
 * g_win32_get_package_installation_directory() for more details. In
 * particular, note that it is deprecated to pass anything except NULL
 * as @package.
 *
 * Returns: a string containing the complete path to @subdir inside
 * the installation directory of @package. The returned string is in
 * the GLib file name encoding, i.e. UTF-8. The return value should be
 * freed with g_free() when no longer needed. If something goes wrong,
 * %NULL is returned.
 *
 * Deprecated: 2.18: Pass the HMODULE of a DLL or EXE to
 * g_win32_get_package_installation_directory_of_module() instead, and
 * then construct a subdirectory pathname with g_build_filename().
 **/

gchar *
g_win32_get_package_installation_subdirectory (const gchar *package,
                                               const gchar *dll_name,
                                               const gchar *subdir)
{
  gchar *prefix;
  gchar *dirname;

G_GNUC_BEGIN_IGNORE_DEPRECATIONS
  prefix = g_win32_get_package_installation_directory (package, dll_name);
G_GNUC_END_IGNORE_DEPRECATIONS

  dirname = g_build_filename (prefix, subdir, NULL);
  g_free (prefix);

  return dirname;
}

/*
 * private API to call Windows's RtlGetVersion(), which may need to be called
 * via GetProcAddress()
 */
gboolean
_g_win32_call_rtl_version (OSVERSIONINFOEXW *info)
{
  static OSVERSIONINFOEXW result;
  static gsize inited = 0;

  g_return_val_if_fail (info != NULL, FALSE);

  if (g_once_init_enter (&inited))
    {
#if WINAPI_FAMILY != MODERN_API_FAMILY
      /* For non-modern UI Apps, use the LoadLibraryW()/GetProcAddress() thing */
      typedef NTSTATUS (WINAPI fRtlGetVersion) (PRTL_OSVERSIONINFOEXW);

      fRtlGetVersion *RtlGetVersion;
      HMODULE hmodule = LoadLibraryW (L"ntdll.dll");
      g_return_val_if_fail (hmodule != NULL, FALSE);

      RtlGetVersion = (fRtlGetVersion *) GetProcAddress (hmodule, "RtlGetVersion");
      g_return_val_if_fail (RtlGetVersion != NULL, FALSE);
#endif

      memset (&result, 0, sizeof (OSVERSIONINFOEXW));
      result.dwOSVersionInfoSize = sizeof (OSVERSIONINFOEXW);

      RtlGetVersion (&result);

#if WINAPI_FAMILY != MODERN_API_FAMILY
      FreeLibrary (hmodule);
#endif
      g_once_init_leave (&inited, TRUE);
    }

  *info = result;

  return TRUE;
}

/**
 * g_win32_check_windows_version:
 * @major: major version of Windows
 * @minor: minor version of Windows
 * @spver: Windows Service Pack Level, 0 if none
 * @os_type: Type of Windows OS
 *
 * Returns whether the version of the Windows operating system the
 * code is running on is at least the specified major, minor and
 * service pack versions.  See MSDN documentation for the Operating
 * System Version.  Software that needs even more detailed version and
 * feature information should use the Win32 API VerifyVersionInfo()
 * directly.
 *
 * Successive calls of this function can be used for enabling or
 * disabling features at run-time for a range of Windows versions,
 * as per the VerifyVersionInfo() API documentation.
 *
 * Returns: %TRUE if the Windows Version is the same or greater than
 *          the specified major, minor and service pack versions, and
 *          whether the running Windows is a workstation or server edition
 *          of Windows, if specifically specified.
 *
 * Since: 2.44
 **/
gboolean
g_win32_check_windows_version (const gint major,
                               const gint minor,
                               const gint spver,
                               const GWin32OSType os_type)
{
  OSVERSIONINFOEXW osverinfo;
  gboolean is_ver_checked = FALSE;
  gboolean is_type_checked = FALSE;

  /* We Only Support Checking for XP or later */
  g_return_val_if_fail (major >= 5 && (major <= 6 || major == 10), FALSE);
  g_return_val_if_fail ((major >= 5 && minor >= 1) || major >= 6, FALSE);

  /* Check for Service Pack Version >= 0 */
  g_return_val_if_fail (spver >= 0, FALSE);

  if (!_g_win32_call_rtl_version (&osverinfo))
    return FALSE;

  /* check the OS and Service Pack Versions */
  if (osverinfo.dwMajorVersion > (DWORD) major)
    is_ver_checked = TRUE;
  else if (osverinfo.dwMajorVersion == (DWORD) major)
    {
      if (osverinfo.dwMinorVersion > (DWORD) minor)
        is_ver_checked = TRUE;
      else if (osverinfo.dwMinorVersion == (DWORD) minor)
        if (osverinfo.wServicePackMajor >= (DWORD) spver)
          is_ver_checked = TRUE;
    }

  /* Check OS Type */
  if (is_ver_checked)
    {
      switch (os_type)
        {
          case G_WIN32_OS_ANY:
            is_type_checked = TRUE;
            break;
          case G_WIN32_OS_WORKSTATION:
            if (osverinfo.wProductType == VER_NT_WORKSTATION)
              is_type_checked = TRUE;
            break;
          case G_WIN32_OS_SERVER:
            if (osverinfo.wProductType == VER_NT_SERVER ||
                osverinfo.wProductType == VER_NT_DOMAIN_CONTROLLER)
              is_type_checked = TRUE;
            break;
          default:
            /* shouldn't get here normally */
            g_warning ("Invalid os_type specified");
            break;
        }
    }

  return is_ver_checked && is_type_checked;
}

/**
 * g_win32_get_windows_version:
 *
 * This function is deprecated. Use
 * g_win32_check_windows_version() instead.
 *
 * Returns version information for the Windows operating system the
 * code is running on. See MSDN documentation for the GetVersion()
 * function. To summarize, the most significant bit is one on Win9x,
 * and zero on NT-based systems. Since version 2.14, GLib works only
 * on NT-based systems, so checking whether your are running on Win9x
 * in your own software is moot. The least significant byte is 4 on
 * Windows NT 4, and 5 on Windows XP. Software that needs really
 * detailed version and feature information should use Win32 API like
 * GetVersionEx() and VerifyVersionInfo().
 *
 * Returns: The version information.
 *
 * Deprecated: 2.44: Be aware that for Windows 8.1 and Windows Server
 * 2012 R2 and later, this will return 62 unless the application is
 * manifested for Windows 8.1/Windows Server 2012 R2, for example.
 * MSDN stated that GetVersion(), which is used here, is subject to
 * further change or removal after Windows 8.1.
 **/
guint
g_win32_get_windows_version (void)
{
  static gsize windows_version;

  if (g_once_init_enter (&windows_version))
    g_once_init_leave (&windows_version, GetVersion ());

  return windows_version;
}

/*
 * Doesn't use gettext (and gconv), preventing recursive calls when
 * g_win32_locale_filename_from_utf8() is called during
 * gettext initialization.
 */
static gchar *
special_wchar_to_locale_encoding (wchar_t *wstring)
{
  int sizeof_output;
  int wctmb_result;
  char *result;
  BOOL not_representable = FALSE;

  sizeof_output = WideCharToMultiByte (CP_ACP,
                                       WC_NO_BEST_FIT_CHARS,
                                       wstring, -1,
                                       NULL, 0,
                                       NULL,
                                       &not_representable);

  if (not_representable ||
      sizeof_output == 0 ||
      sizeof_output > MAX_PATH)
    return NULL;

  result = g_malloc0 (sizeof_output + 1);

  wctmb_result = WideCharToMultiByte (CP_ACP,
                                      WC_NO_BEST_FIT_CHARS,
                                      wstring, -1,
                                      result, sizeof_output + 1,
                                      NULL,
                                      &not_representable);

  if (wctmb_result == sizeof_output &&
      not_representable == FALSE)
    return result;

  g_free (result);

  return NULL;
}

/**
 * g_win32_locale_filename_from_utf8:
 * @utf8filename: a UTF-8 encoded filename.
 *
 * Converts a filename from UTF-8 to the system codepage.
 *
 * On NT-based Windows, on NTFS file systems, file names are in
 * Unicode. It is quite possible that Unicode file names contain
 * characters not representable in the system codepage. (For instance,
 * Greek or Cyrillic characters on Western European or US Windows
 * installations, or various less common CJK characters on CJK Windows
 * installations.)
 *
 * In such a case, and if the filename refers to an existing file, and
 * the file system stores alternate short (8.3) names for directory
 * entries, the short form of the filename is returned. Note that the
 * "short" name might in fact be longer than the Unicode name if the
 * Unicode name has very short pathname components containing
 * non-ASCII characters. If no system codepage name for the file is
 * possible, %NULL is returned.
 *
 * The return value is dynamically allocated and should be freed with
 * g_free() when no longer needed.
 *
 * Returns: The converted filename, or %NULL on conversion
 * failure and lack of short names.
 *
 * Since: 2.8
 */
gchar *
g_win32_locale_filename_from_utf8 (const gchar *utf8filename)
{
  gchar *retval;
  wchar_t *wname;

  wname = g_utf8_to_utf16 (utf8filename, -1, NULL, NULL, NULL);

  if (wname == NULL)
    return NULL;

  retval = special_wchar_to_locale_encoding (wname);

  if (retval == NULL)
    {
      /* Conversion failed, so check if there is a 8.3 version, and use that. */
      wchar_t wshortname[MAX_PATH + 1];

      if (GetShortPathNameW (wname, wshortname, G_N_ELEMENTS (wshortname)))
        retval = special_wchar_to_locale_encoding (wshortname);
    }

  g_free (wname);

  return retval;
}

/**
 * g_win32_get_command_line:
 *
 * Gets the command line arguments, on Windows, in the GLib filename
 * encoding (ie: UTF-8).
 *
 * Normally, on Windows, the command line arguments are passed to main()
 * in the system codepage encoding.  This prevents passing filenames as
 * arguments if the filenames contain characters that fall outside of
 * this codepage.  If such filenames are passed, then substitutions
 * will occur (such as replacing some characters with '?').
 *
 * GLib's policy of using UTF-8 as a filename encoding on Windows was
 * designed to localise the pain of dealing with filenames outside of
 * the system codepage to one area: dealing with commandline arguments
 * in main().
 *
 * As such, most GLib programs should ignore the value of argv passed to
 * their main() function and call g_win32_get_command_line() instead.
 * This will get the "full Unicode" commandline arguments using
 * GetCommandLineW() and convert it to the GLib filename encoding (which
 * is UTF-8 on Windows).
 *
 * The strings returned by this function are suitable for use with
 * functions such as g_open() and g_file_new_for_commandline_arg() but
 * are not suitable for use with g_option_context_parse(), which assumes
 * that its input will be in the system codepage.  The return value is
 * suitable for use with g_option_context_parse_strv(), however, which
 * is a better match anyway because it won't leak memory.
 *
 * Unlike argv, the returned value is a normal strv and can (and should)
 * be freed with g_strfreev() when no longer needed.
 *
 * Returns: (transfer full): the commandline arguments in the GLib
 *   filename encoding (ie: UTF-8)
 *
 * Since: 2.40
 **/
gchar **
g_win32_get_command_line (void)
{
  gchar **result;
  LPWSTR *args;
  gint i, n;

  args = CommandLineToArgvW (GetCommandLineW(), &n);

  result = g_new (gchar *, n + 1);
  for (i = 0; i < n; i++)
    result[i] = g_utf16_to_utf8 (args[i], -1, NULL, NULL, NULL);
  result[i] = NULL;

  LocalFree (args);
  return result;
}

/* Binary compatibility versions. Not for newly compiled code. */

_GLIB_EXTERN gchar *g_win32_get_package_installation_directory_utf8    (const gchar *package,
                                                                        const gchar *dll_name);

_GLIB_EXTERN gchar *g_win32_get_package_installation_subdirectory_utf8 (const gchar *package,
                                                                        const gchar *dll_name,
                                                                        const gchar *subdir);

gchar *
g_win32_get_package_installation_directory_utf8 (const gchar *package,
                                                 const gchar *dll_name)
{
G_GNUC_BEGIN_IGNORE_DEPRECATIONS
  return g_win32_get_package_installation_directory (package, dll_name);
G_GNUC_END_IGNORE_DEPRECATIONS
}

gchar *
g_win32_get_package_installation_subdirectory_utf8 (const gchar *package,
                                                    const gchar *dll_name,
                                                    const gchar *subdir)
{
G_GNUC_BEGIN_IGNORE_DEPRECATIONS
  return g_win32_get_package_installation_subdirectory (package,
                                                        dll_name,
                                                        subdir);
G_GNUC_END_IGNORE_DEPRECATIONS
}

/* This function looks up two environment
 * variables, G_WIN32_ALLOC_CONSOLE and G_WIN32_ATTACH_CONSOLE.
 * G_WIN32_ALLOC_CONSOLE, if set to 1, makes the process
 * call AllocConsole(). This is useful for binaries that
 * are compiled to run without automatically-allocated console
 * (like most GUI applications).
 * G_WIN32_ATTACH_CONSOLE, if set to a comma-separated list
 * of one or more strings "stdout", "stdin" and "stderr",
 * makes the process reopen the corresponding standard streams
 * to ensure that they are attached to the files that
 * GetStdHandle() returns, which, hopefully, would be
 * either a file handle or a console handle.
 *
 * This function is called automatically when glib DLL is
 * attached to a process, from DllMain().
 */
void
g_console_win32_init (void)
{
  struct
    {
      gboolean     redirect;
      FILE        *stream;
      const gchar *stream_name;
      DWORD        std_handle_type;
      int          flags;
      const gchar *mode;
    }
  streams[] =
    {
      { FALSE, stdin, "stdin", STD_INPUT_HANDLE, _O_RDONLY, "rb" },
      { FALSE, stdout, "stdout", STD_OUTPUT_HANDLE, 0, "wb" },
      { FALSE, stderr, "stderr", STD_ERROR_HANDLE, 0, "wb" },
    };

  const gchar  *attach_envvar;
  guint         i;
  gchar       **attach_strs;

  /* Note: it's not a very good practice to use DllMain()
   * to call any functions not in Kernel32.dll.
   * The following only works if there are no weird
   * circular DLL dependencies that could cause glib DllMain()
   * to be called before CRT DllMain().
   */

  if (g_strcmp0 (g_getenv ("G_WIN32_ALLOC_CONSOLE"), "1") == 0)
    AllocConsole (); /* no error handling, fails if console already exists */

  attach_envvar = g_getenv ("G_WIN32_ATTACH_CONSOLE");

  if (attach_envvar == NULL)
    return;

  /* Re-use parent console, if we don't have our own.
   * If we do, it will fail, so just ignore the error.
   */
  AttachConsole (ATTACH_PARENT_PROCESS);

  attach_strs = g_strsplit (attach_envvar, ",", -1);

  for (i = 0; attach_strs[i]; i++)
    {
      if (g_strcmp0 (attach_strs[i], "stdout") == 0)
        streams[1].redirect = TRUE;
      else if (g_strcmp0 (attach_strs[i], "stderr") == 0)
        streams[2].redirect = TRUE;
      else if (g_strcmp0 (attach_strs[i], "stdin") == 0)
        streams[0].redirect = TRUE;
      else
        g_warning ("Unrecognized stream name %s", attach_strs[i]);
    }

  g_strfreev (attach_strs);

  for (i = 0; i < G_N_ELEMENTS (streams); i++)
    {
      int          old_fd;
      int          backup_fd;
      int          new_fd;
      int          preferred_fd = i;
      HANDLE       std_handle;
      errno_t      errsv = 0;

      if (!streams[i].redirect)
        continue;

      if (ferror (streams[i].stream) != 0)
        {
          g_warning ("Stream %s is in error state", streams[i].stream_name);
          continue;
        }

      std_handle = GetStdHandle (streams[i].std_handle_type);

      if (std_handle == INVALID_HANDLE_VALUE)
        {
          DWORD gle = GetLastError ();
          g_warning ("Standard handle for %s can't be obtained: %lu",
                     streams[i].stream_name, gle);
          continue;
        }

      old_fd = fileno (streams[i].stream);

      /* We need the stream object to be associated with
       * any valid integer fd for the code to work.
       * If it isn't, reopen it with NUL (/dev/null) to
       * ensure that it is.
       */
      if (old_fd < 0)
        {
          if (freopen ("NUL", streams[i].mode, streams[i].stream) == NULL)
            {
              errsv = errno;
              g_warning ("Failed to redirect %s: %d - %s",
                         streams[i].stream_name,
                         errsv,
                         strerror (errsv));
              continue;
            }

          old_fd = fileno (streams[i].stream);

          if (old_fd < 0)
            {
              g_warning ("Stream %s does not have a valid fd",
                         streams[i].stream_name);
              continue;
            }
        }

      new_fd = _open_osfhandle ((intptr_t) std_handle, streams[i].flags);

      if (new_fd < 0)
        {
          g_warning ("Failed to create new fd for stream %s",
                     streams[i].stream_name);
          continue;
        }

      backup_fd = dup (old_fd);

      if (backup_fd < 0)
        g_warning ("Failed to backup old fd %d for stream %s",
                   old_fd, streams[i].stream_name);

      errno = 0;

      /* Force old_fd to be associated with the same file
       * as new_fd, i.e with the standard handle we need
       * (or, rather, with the same kernel object; handle
       * value will be different, but the kernel object
       * won't be).
       */
      /* NOTE: MSDN claims that _dup2() returns 0 on success and -1 on error,
       * POSIX claims that dup2() reurns new FD on success and -1 on error.
       * The "< 0" check satisfies the error condition for either implementation.
       */
      if (_dup2 (new_fd, old_fd) < 0)
        {
          errsv = errno;
          g_warning ("Failed to substitute fd %d for stream %s: %d : %s",
                     old_fd, streams[i].stream_name, errsv, strerror (errsv));

          _close (new_fd);

          if (backup_fd < 0)
            continue;

          errno = 0;

          /* Try to restore old_fd back to its previous
           * handle, in case the _dup2() call above succeeded partially.
           */
          if (_dup2 (backup_fd, old_fd) < 0)
            {
              errsv = errno;
              g_warning ("Failed to restore fd %d for stream %s: %d : %s",
                         old_fd, streams[i].stream_name, errsv, strerror (errsv));
            }

          _close (backup_fd);

          continue;
        }

      /* Success, drop the backup */
      if (backup_fd >= 0)
        _close (backup_fd);

      /* Sadly, there's no way to check that preferred_fd
       * is currently valid, so we can't back it up.
       * Doing operations on invalid FDs invokes invalid
       * parameter handler, which is bad for us.
       */
      if (old_fd != preferred_fd)
        /* This extra code will also try to ensure that
         * the expected file descriptors 0, 1 and 2 are
         * associated with the appropriate standard
         * handles.
         */
        if (_dup2 (new_fd, preferred_fd) < 0)
          g_warning ("Failed to dup fd %d into fd %d", new_fd, preferred_fd);

      _close (new_fd);
    }
}

/* This is a handle to the Vectored Exception Handler that
 * we install on library initialization. If installed correctly,
 * it will be non-NULL. Only used to later de-install the handler
 * on library de-initialization.
 */
static void        *WinVEH_handle = NULL;

#define             DEBUGGER_BUFFER_SIZE (MAX_PATH + 1)
/* This is the debugger that we'll run on crash */
static wchar_t      debugger[DEBUGGER_BUFFER_SIZE];

static gsize        number_of_exceptions_to_catch = 0;
static DWORD       *exceptions_to_catch = NULL;

static HANDLE       debugger_wakeup_event = 0;
static DWORD        debugger_spawn_flags = 0;

/* Copy @cmdline into @debugger, and substitute @pid for `%p`
 * and @event for `%e`.
 * If @debugger_size (in wchar_ts) is overflowed, return %FALSE.
 * Also returns %FALSE when `%` is followed by anything other
 * than `e` or `p`.
 */
bool
g_win32_substitute_pid_and_event (wchar_t       *local_debugger,
                                  gsize          debugger_size,
                                  const wchar_t *cmdline,
                                  DWORD          pid,
                                  guintptr       event)
{
  gsize i = 0, dbg_i = 0;
/* These are integers, and they can't be longer than 20 characters
 * even when they are 64-bit and in decimal notation.
 * Use 30 just to be sure.
 */
#define STR_BUFFER_SIZE 30
  wchar_t pid_str[STR_BUFFER_SIZE] = {0};
  gsize pid_str_len;
  wchar_t event_str[STR_BUFFER_SIZE] = {0};
  gsize event_str_len;

  _snwprintf_s (pid_str, STR_BUFFER_SIZE, G_N_ELEMENTS (pid_str), L"%lu", pid);
  pid_str[G_N_ELEMENTS (pid_str) - 1] = 0;
  pid_str_len = wcslen (pid_str);
  _snwprintf_s (event_str, STR_BUFFER_SIZE, G_N_ELEMENTS (pid_str), L"%Iu", event);
  event_str[G_N_ELEMENTS (pid_str) - 1] = 0;
  event_str_len = wcslen (event_str);
#undef STR_BUFFER_SIZE

  while (cmdline[i] != 0 && dbg_i < debugger_size)
    {
      if (cmdline[i] != L'%')
        local_debugger[dbg_i++] = cmdline[i++];
      else if (cmdline[i + 1] == L'p')
        {
          gsize j = 0;
          while (j < pid_str_len && dbg_i < debugger_size)
            local_debugger[dbg_i++] = pid_str[j++];
          i += 2;
        }
      else if (cmdline[i + 1] == L'e')
        {
          gsize j = 0;
          while (j < event_str_len && dbg_i < debugger_size)
            local_debugger[dbg_i++] = event_str[j++];
          i += 2;
        }
      else
        return FALSE;
    }
  if (dbg_i < debugger_size)
    local_debugger[dbg_i] = 0;
  else
    return FALSE;

  return TRUE;
}

static char *
copy_chars (char       *buffer,
            gsize      *buffer_size,
            const char *to_copy)
{
  gsize copy_count = MIN (strlen (to_copy), *buffer_size - 1);
  memset (buffer, 0x20, copy_count);
  strncpy_s (buffer, *buffer_size, to_copy, _TRUNCATE);
  *buffer_size -= copy_count;
  return &buffer[copy_count];
}

/* Handles exceptions (useful for debugging).
 * Issues a DebugBreak() call if the process is being debugged (not really
 * useful - if the process is being debugged, this handler won't be invoked
 * anyway). If it is not, runs a debugger from G_DEBUGGER env var,
 * substituting first %p in it for PID, and the first %e for the event handle -
 * that event should be set once the debugger attaches itself (otherwise the
 * only way out of WaitForSingleObject() is to time out after 1 minute).
 * For example, G_DEBUGGER can be set to the following command:
 * ```
 * gdb.exe -ex "attach %p" -ex "signal-event %e" -ex "bt" -ex "c"
 * ```
 * This will make GDB attach to the process, signal the event (GDB must be
 * recent enough for the signal-event command to be available),
 * show the backtrace and resume execution, which should make it catch
 * the exception when Windows re-raises it again.
 * The command line can't be longer than MAX_PATH (260 characters).
 *
 * This function will only stop (and run a debugger) on the following exceptions:
 * * EXCEPTION_ACCESS_VIOLATION
 * * EXCEPTION_STACK_OVERFLOW
 * * EXCEPTION_ILLEGAL_INSTRUCTION
 * To make it stop at other exceptions one should set the G_VEH_CATCH
 * environment variable to a list of comma-separated hexadecimal numbers,
 * where each number is the code of an exception that should be caught.
 * This is done to prevent GLib from breaking when Windows uses
 * exceptions to shuttle information (SetThreadName(), OutputDebugString())
 * or for control flow.
 *
 * This function deliberately avoids calling any GLib code.
 * This is done on purpose. This function can be called when the program
 * is in a bad state (crashing). It can also be called very early, as soon
 * as the handler is installed. Therefore, it's imperative that
 * it does as little as possible. Preferably, all the work that can be
 * done in advance (when the program is not crashing yet) should be done
 * in advance.
 */
static LONG __stdcall
g_win32_veh_handler (PEXCEPTION_POINTERS ExceptionInfo)
{
  EXCEPTION_RECORD    *er;
  gsize                i;
  STARTUPINFOW         si;
  PROCESS_INFORMATION  pi;
#define ITOA_BUFFER_SIZE 100
  char                 itoa_buffer[ITOA_BUFFER_SIZE];
#define DEBUG_STRING_SIZE 1024
  gsize                dbgs = DEBUG_STRING_SIZE;
  char                 debug_string[DEBUG_STRING_SIZE];
  char                *dbgp;

  if (ExceptionInfo == NULL ||
      ExceptionInfo->ExceptionRecord == NULL ||
      IsDebuggerPresent () ||
      debugger[0] == 0)
    return EXCEPTION_CONTINUE_SEARCH;

  er = ExceptionInfo->ExceptionRecord;

  switch (er->ExceptionCode)
    {
    case EXCEPTION_ACCESS_VIOLATION:
    case EXCEPTION_STACK_OVERFLOW:
    case EXCEPTION_ILLEGAL_INSTRUCTION:
      break;
    default:
      for (i = 0; i < number_of_exceptions_to_catch; i++)
        if (exceptions_to_catch[i] == er->ExceptionCode)
          break;

      if (i == number_of_exceptions_to_catch)
        return EXCEPTION_CONTINUE_SEARCH;

      break;
    }

  memset (&si, 0, sizeof (si));
  memset (&pi, 0, sizeof (pi));
  si.cb = sizeof (si);

  /* Run the debugger */
  if (0 != CreateProcessW (NULL, debugger, NULL, NULL, TRUE, debugger_spawn_flags, NULL, NULL, &si, &pi))
    {
      CloseHandle (pi.hProcess);
      CloseHandle (pi.hThread);
      /* If successful, wait for 60 seconds on the event
       * we passed. The debugger should signal that event.
       * 60 second limit is here to prevent us from hanging
       * up forever in case the debugger does not support
       * event signalling.
       */
      WaitForSingleObject (debugger_wakeup_event, 60000);

      dbgp = &debug_string[0];

      dbgp = copy_chars (dbgp, &dbgs, "Exception code=0x");
      itoa_buffer[0] = 0;
      _ui64toa_s (er->ExceptionCode, itoa_buffer, ITOA_BUFFER_SIZE, 16);
      dbgp = copy_chars (dbgp, &dbgs, itoa_buffer);
      dbgp = copy_chars (dbgp, &dbgs, " flags=0x");
      itoa_buffer[0] = 0;
      _ui64toa_s (er->ExceptionFlags, itoa_buffer, ITOA_BUFFER_SIZE, 16);
      dbgp = copy_chars (dbgp, &dbgs, itoa_buffer);
      dbgp = copy_chars (dbgp, &dbgs, " at 0x");
      itoa_buffer[0] = 0;
      _ui64toa_s ((guintptr) er->ExceptionAddress, itoa_buffer, ITOA_BUFFER_SIZE, 16);
      dbgp = copy_chars (dbgp, &dbgs, itoa_buffer);

      switch (er->ExceptionCode)
        {
        case EXCEPTION_ACCESS_VIOLATION:
          dbgp = copy_chars (dbgp, &dbgs, ". Access violation - attempting to ");
          if (er->ExceptionInformation[0] == 0)
            dbgp = copy_chars (dbgp, &dbgs, "read data");
          else if (er->ExceptionInformation[0] == 1)
            dbgp = copy_chars (dbgp, &dbgs, "write data");
          else if (er->ExceptionInformation[0] == 8)
            dbgp = copy_chars (dbgp, &dbgs, "execute data");
          else
            dbgp = copy_chars (dbgp, &dbgs, "do something bad");
          dbgp = copy_chars (dbgp, &dbgs, " at address 0x");
          itoa_buffer[0] = 0;
          _ui64toa_s (er->ExceptionInformation[1], itoa_buffer, ITOA_BUFFER_SIZE, 16);
          dbgp = copy_chars (dbgp, &dbgs, itoa_buffer);
          break;
        case EXCEPTION_IN_PAGE_ERROR:
          dbgp = copy_chars (dbgp, &dbgs, ". Page access violation - attempting to ");
          if (er->ExceptionInformation[0] == 0)
            dbgp = copy_chars (dbgp, &dbgs, "read from an inaccessible page");
          else if (er->ExceptionInformation[0] == 1)
            dbgp = copy_chars (dbgp, &dbgs, "write to an inaccessible page");
          else if (er->ExceptionInformation[0] == 8)
            dbgp = copy_chars (dbgp, &dbgs, "execute data in page");
          else
            dbgp = copy_chars (dbgp, &dbgs, "do something bad with a page");
          dbgp = copy_chars (dbgp, &dbgs, " at address 0x");
          itoa_buffer[0] = 0;
          _ui64toa_s (er->ExceptionInformation[1], itoa_buffer, ITOA_BUFFER_SIZE, 16);
          dbgp = copy_chars (dbgp, &dbgs, itoa_buffer);
          dbgp = copy_chars (dbgp, &dbgs, " with status ");
          itoa_buffer[0] = 0;
          _ui64toa_s (er->ExceptionInformation[2], itoa_buffer, ITOA_BUFFER_SIZE, 16);
          dbgp = copy_chars (dbgp, &dbgs, itoa_buffer);
          break;
        default:
          break;
        }

      dbgp = copy_chars (dbgp, &dbgs, "\n");
      OutputDebugStringA (debug_string);
    }

  /* Now the debugger is present, and we can try
   * resuming execution, re-triggering the exception,
   * which will be caught by debugger this time around.
   */
  if (IsDebuggerPresent ())
    return EXCEPTION_CONTINUE_EXECUTION;

  return EXCEPTION_CONTINUE_SEARCH;
}

static gsize
parse_catch_list (const wchar_t *catch_buffer,
                  DWORD         *exceptions,
                  gsize          num_exceptions)
{
  const wchar_t *catch_list = catch_buffer;
  gsize          result = 0;
  gsize          i = 0;

  while (catch_list != NULL &&
         catch_list[0] != 0)
    {
      unsigned long  catch_code;
      wchar_t       *end;
      errno = 0;
      catch_code = wcstoul (catch_list, &end, 16);
      if (errno != NO_ERROR)
        break;
      catch_list = end;
      if (catch_list != NULL && catch_list[0] == L',')
        catch_list++;
      if (exceptions && i < num_exceptions)
        exceptions[i++] = catch_code;
    }

  return result;
}

void
g_crash_handler_win32_init (void)
{
  wchar_t      debugger_env[DEBUGGER_BUFFER_SIZE];
#define CATCH_BUFFER_SIZE 1024
  wchar_t      catch_buffer[CATCH_BUFFER_SIZE];
  SECURITY_ATTRIBUTES  sa;

  if (WinVEH_handle != NULL)
    return;

  /* Do not register an exception handler if we're not supposed to catch any
   * exceptions. Exception handlers are considered dangerous to use, and can
   * break advanced exception handling such as in CLRs like C# or other managed
   * code. See: http://www.windows-tech.info/13/785f590867bd6316.php
   */
  debugger_env[0] = 0;
  if (!GetEnvironmentVariableW (L"G_DEBUGGER", debugger_env, DEBUGGER_BUFFER_SIZE))
    return;

  /* Create an inheritable event */
  memset (&sa, 0, sizeof (sa));
  sa.nLength = sizeof (sa);
  sa.bInheritHandle = TRUE;
  debugger_wakeup_event = CreateEvent (&sa, FALSE, FALSE, NULL);

  /* Put process ID and event handle into debugger commandline */
  if (!g_win32_substitute_pid_and_event (debugger, G_N_ELEMENTS (debugger),
                                         debugger_env, GetCurrentProcessId (),
                                         (guintptr) debugger_wakeup_event))
    {
      CloseHandle (debugger_wakeup_event);
      debugger_wakeup_event = 0;
      debugger[0] = 0;
      return;
    }
  debugger[MAX_PATH] = L'\0';

  catch_buffer[0] = 0;
  if (GetEnvironmentVariableW (L"G_VEH_CATCH", catch_buffer, CATCH_BUFFER_SIZE))
    {
      number_of_exceptions_to_catch = parse_catch_list (catch_buffer, NULL, 0);
      if (number_of_exceptions_to_catch > 0)
        {
          exceptions_to_catch = g_new0 (DWORD, number_of_exceptions_to_catch);
          parse_catch_list (catch_buffer, exceptions_to_catch, number_of_exceptions_to_catch);
        }
    }

  if (GetEnvironmentVariableW (L"G_DEBUGGER_OLD_CONSOLE", (wchar_t *) &debugger_spawn_flags, 1))
    debugger_spawn_flags = 0;
  else
    debugger_spawn_flags = CREATE_NEW_CONSOLE;

  WinVEH_handle = AddVectoredExceptionHandler (0, &g_win32_veh_handler);
}

void
g_crash_handler_win32_deinit (void)
{
  if (WinVEH_handle != NULL)
    RemoveVectoredExceptionHandler (WinVEH_handle);

  WinVEH_handle = NULL;
}

/**
 * g_win32_find_helper_executable_path:
 * @executable_name: (transfer none): name of the helper executable to find
 * (something like gspawn-win64-helper.exe or gdbus.exe for example).
 * @dll_handle: handle of the DLL to use as searching base path. Pass NULL
 * to take current process executable as searching base path.
 *
 * Find an external executable path and name starting in the same folder
 * as a specified DLL or current process executable path. Helper executables
 * (like gspawn-win64-helper.exe, gspawn-win64-helper-console.exe or
 * gdbus.exe for example) are generally installed in the same folder as the
 * corresponding DLL file.
 *
 * So, if package has been correctly installed, with a dynamic build of GLib,
 * the helper executable should be in the same directory as the corresponding
 * DLL file and searching should be straightforward.
 *
 * But if built statically, DLL handle is not available and we have to start
 * searching from the directory holding current executable. It may be very
 * different from the directory containing the helper program. In order to
 * find the right helper program automatically in all common situations, we
 * use this pattern:
 *
 * current directory
 *             |-- ???
 *             |-- bin
 *             |    |-- ???
 *             |-- lib
 *             |    |-- ???
 *             |-- glib
 *             |    |-- ???
 *             |-- gio
 *                  |-- ???
 *
 * starting at base searching path (DLL or current executable directory) and
 * getting up until the root path. If we cannot still find the helper program,
 * we'll rely on PATH as the last resort.
 *
 * Returns: (transfer full) (type filename) (nullable): the helper executable
 * path and name in the GLib filename encoding or NULL in case of error. It
 * should be deallocated with g_free().
 */
gchar *
g_win32_find_helper_executable_path (const gchar *executable_name, void *dll_handle)
{
  static const gchar *const subdirs[] = { "", "bin", "lib", "glib", "gio" };
  static const gsize nb_subdirs = G_N_ELEMENTS (subdirs);

  DWORD module_path_len;
  wchar_t module_path[MAX_PATH + 2] = { 0 };
  gchar *base_searching_path;
  gchar *p;
  gchar *executable_path;
  gsize i;

  g_return_val_if_fail (executable_name && *executable_name, NULL);

  module_path_len = GetModuleFileNameW (dll_handle, module_path, MAX_PATH + 1);
  /* The > MAX_PATH check prevents truncated module path usage */
  if (module_path_len == 0 || module_path_len > MAX_PATH)
    return NULL;

  base_searching_path = g_utf16_to_utf8 (module_path, -1, NULL, NULL, NULL);
  if (base_searching_path == NULL)
    return NULL;

  p = strrchr (base_searching_path, G_DIR_SEPARATOR);
  if (p == NULL)
    {
      g_free (base_searching_path);
      return NULL;
    }
  *p = '\0';

  for (;;)
    {
      /* Search in subdirectories */
      for (i = 0; i < nb_subdirs; ++i)
        {
          /* As this function is exclusively used on Windows, the
           * executable_path is always an absolute path. At worse, when
           * reaching the root of the filesystem, base_searching_path may
           * equal something like "[Drive letter]:" but never "/" like on
           * Linux or Mac.
           * For the peace of mind we still assert this, just in case that
           * one day someone tries to use this function on Linux or Mac.
           */
          executable_path = g_build_filename (base_searching_path, subdirs[i], executable_name, NULL);
          g_assert (g_path_is_absolute (executable_path));
          if (g_file_test (executable_path, G_FILE_TEST_IS_REGULAR))
            break;

          g_free (executable_path);
          executable_path = NULL;
        }

      if (executable_path != NULL)
        break;

      /* Let's get one directory level up */
      p = strrchr (base_searching_path, G_DIR_SEPARATOR);
      if (p == NULL)
        break;

      *p = '\0';
    }
  g_free (base_searching_path);

  if (executable_path == NULL)
    {
      /* Search in system PATH */
      executable_path = g_find_program_in_path (executable_name);
      if (executable_path == NULL)
        executable_path = g_strdup (executable_name);
    }

  return executable_path;
}

/** < private >
 *
 * g_win32_file_stream_is_console_output:
 *
 * @stream: a FILE stream
 *
 * Checks if the given FILE stream refers to a Win32 console
 * screen buffer.
 */
bool
g_win32_file_stream_is_console_output (FILE *stream)
{
  int fd = _fileno (stream);

  if (fd < 0)
    {
      /* On Windows, FILE streams can be 'open' but not associated
       * with any file descriptor. As far as I know, that can only
       * happen for the standard streams stdin, stdout, and stderr.
       * Window processes can have NULL standard HANDLEs, but the
       * C standard states that standard streams must be 'open'
       * when main is called. So, on Windows, _fileno() is expected
       * to return values < 0 even without errors.
       */
      return false;
    }

  /* We call _isatty() first because it's a very fast check (just
   * checking an internal flag). However, the _isatty check comprehends
   * output devices like serial ports, so we check if the output is
   * really a win32 console with g_win32_handle_is_console_output.
   */
  return _isatty (fd) &&
         g_win32_handle_is_console_output ((HANDLE)_get_osfhandle (fd));
}

/** < private >
 *
 * g_win32_handle_is_console_output:
 *
 * @handle: the given HANDLE
 *
 * Checks if the given HANDLE refers to a Win32 console screen
 * buffer (output HANDLE).
 */
bool
g_win32_handle_is_console_output (HANDLE handle)
{
  /* MSDN suggests using GetConsoleMode() to check if a HANDLE refers to
   * the console. However GetConsoleMode() requires read access rights
   * (FILE_READ_DATA | FILE_READ_ATTRIBUTES | FILE_READ_EA on Windows 10),
   * and output HANDLEs may have been opened with write rights only. To
   * overcome that, we use WriteConsole() with a zero characters count.
   */
  const wchar_t *dummy = L"";
  if (!WriteConsole (handle, dummy, 0, NULL, NULL))
    {
      DWORD code = GetLastError ();

      if (code != ERROR_INVALID_FUNCTION && code != ERROR_INVALID_HANDLE)
        {
          WIN32_API_FAILED ("WriteConsole");
        }

      return false;
    }

  return true;
}

/*
 * g_win32_handle_is_socket:
 * @h: a win32 HANDLE
 *
 * Returns: %TRUE if the handle is a `SOCKET`.
 */
gboolean
g_win32_handle_is_socket (HANDLE h)
{
  int option = 0;
  int optlen = sizeof (option);

  /* according to: https://stackoverflow.com/a/50981652/1277510, this is reasonable */
  if (getsockopt ((SOCKET) h, SOL_SOCKET, SO_DEBUG, (char *) &option, &optlen) == SOCKET_ERROR)
    return FALSE;

  return TRUE;
}

/*
 * g_win32_reopen_noninherited:
 * @fd: (transfer full): A file descriptor
 * @mode: _open_osfhandle flags
 * @error: A location to return an error of type %G_FILE_ERROR
 *
 * Reopen the given @fd with `_O_NOINHERIT`.
 *
 * The @fd is closed on success.
 *
 * Returns: (transfer full): The new file-descriptor, or -1 on error.
 */
int
g_win32_reopen_noninherited (int fd,
                             int mode,
                             GError **error)
{
  HANDLE h;
  HANDLE duph;
  int dupfd, errsv;

  h = (HANDLE) _get_osfhandle (fd);
  errsv = errno;

  if (h == INVALID_HANDLE_VALUE)
    {
      const char *emsg = g_strerror (errsv);
      g_set_error (error, G_FILE_ERROR, g_file_error_from_errno (errsv),
                   "_get_osfhandle() failed: %s", emsg);
      return -1;
    }

  if (g_win32_handle_is_socket (h))
    {
      WSAPROTOCOL_INFO info;

      if (WSADuplicateSocket ((SOCKET) h,
                              GetCurrentProcessId (),
                              &info))
        {
          gchar *emsg = g_win32_error_message (WSAGetLastError ());
          g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_FAILED,
                       "WSADuplicateSocket() failed: %s", emsg);
          g_free (emsg);
          return -1;
        }

      duph = (HANDLE) WSASocket (FROM_PROTOCOL_INFO,
                                 FROM_PROTOCOL_INFO,
                                 FROM_PROTOCOL_INFO,
                                 &info, 0, 0);
      if (duph == (HANDLE) INVALID_SOCKET)
        {
          gchar *emsg = g_win32_error_message (WSAGetLastError ());
          g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_FAILED,
                       "WSASocket() failed: %s", emsg);
          g_free (emsg);
          return -1;
        }
    }
  else if (DuplicateHandle (GetCurrentProcess (), h,
                            GetCurrentProcess (), &duph,
                            0, FALSE, DUPLICATE_SAME_ACCESS) == 0)
    {
      char *emsg = g_win32_error_message (GetLastError ());
      g_set_error (error, G_FILE_ERROR, G_FILE_ERROR_FAILED,
                   "DuplicateHandle() failed: %s", emsg);
      g_free (emsg);
      return -1;
    }

  /* the duph ownership is transferred to dupfd */
  dupfd = _open_osfhandle ((gintptr) duph, mode | _O_NOINHERIT);
  if (dupfd < 0)
    {
      g_set_error_literal (error, G_FILE_ERROR, G_FILE_ERROR_FAILED,
                           "_open_osfhandle() failed");
      CloseHandle (duph);
      return -1;
    }

  if (!g_close (fd, error))
    {
      /* ignore extra errors in this case */
      g_close (dupfd, NULL);
      return -1;
    }

  return dupfd;
}

bool
g_win32_error_message_in_place (DWORD    code,
                                wchar_t *buffer,
                                size_t   wchars_count)
{
  const DWORD flags = FORMAT_MESSAGE_FROM_SYSTEM |
                      FORMAT_MESSAGE_IGNORE_INSERTS;
  DWORD wchars_written;

  g_assert (wchars_count > 0);

  wchars_written = FormatMessage (flags, NULL, code, 0, buffer, wchars_count - 1, NULL);
  if (wchars_written == 0)
    return false;

  g_assert (wchars_written < wchars_count);

  if (wchars_written >= 2)
    {
      wchars_written -= (buffer[wchars_written - 1] == L'\n') +
                        (buffer[wchars_written - 2] == L'\r');
    }

  buffer[wchars_written] = L'\0';

  return true;
}

/** < private >
 *
 * g_win32_api_failed:
 *
 * @where: location in the source code
 * @api: name of the failing API
 * @code: a Windows error code or a failing HRESULT
 *
 * Prints a warning about the failing API with an extended
 * error description (see g_win32_error_message).
 */
void
g_win32_api_failed_with_code (const char *where,
                              const char *api,
                              DWORD       code)
{
  wchar_t description[500];

  if (g_win32_error_message_in_place (code, description, G_N_ELEMENTS (description)))
    g_warning ("%s failed: %S", api, description);
  else
    g_warning ("%s failed with error code %u", api, (unsigned int) code);
}

/** < private >
 *
 * g_win32_api_failed:
 *
 * @where: location in the source code
 * @api: name of the failing API
 *
 * Prints a warning about the failing API with an extended
 * error description (see g_win32_error_message).
 */
void
g_win32_api_failed (const char *where,
                    const char *api)
{
  g_win32_api_failed_with_code (where, api, GetLastError ());
}
