/* Core of implementation of fstat and stat for native Windows.

   Copyright (C) 2017-2020 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible.  */

#include <config.h>

#if defined _WIN32 && ! defined __CYGWIN__

/* Ensure that <windows.h> defines FILE_ID_INFO.  */

#if !defined _WIN32_WINNT || (_WIN32_WINNT < _WIN32_WINNT_WIN8)

# undef _WIN32_WINNT

# define _WIN32_WINNT _WIN32_WINNT_WIN8

#endif

#include <sys/types.h>

#include <sys/stat.h>

#include <errno.h>

#include <limits.h>

#include <string.h>

#include <unistd.h>

#include <windows.h>

/* Specification.  */

#include "stat-w32.h"

#include "pathmax.h"

#include "verify.h"

#if !(_WIN32_WINNT >= _WIN32_WINNT_VISTA)

/* Avoid warnings from gcc -Wcast-function-type.  */

# define GetProcAddress \

   (void *) GetProcAddress

# if _GL_WINDOWS_STAT_INODES == 2

/* GetFileInformationByHandleEx was introduced only in Windows Vista.  */

typedef DWORD (WINAPI * GetFileInformationByHandleExFuncType) (HANDLE hFile,

                                                               FILE_INFO_BY_HANDLE_CLASS fiClass,

                                                               LPVOID lpBuffer,

                                                               DWORD dwBufferSize);

static GetFileInformationByHandleExFuncType GetFileInformationByHandleExFunc = NULL;

# endif

/* GetFinalPathNameByHandle was introduced only in Windows Vista.  */

typedef DWORD (WINAPI * GetFinalPathNameByHandleFuncType) (HANDLE hFile,

                                                           LPSTR lpFilePath,

                                                           DWORD lenFilePath,

                                                           DWORD dwFlags);

static GetFinalPathNameByHandleFuncType GetFinalPathNameByHandleFunc = NULL;

static BOOL initialized = FALSE;

static void

initialize (void)

{

  HMODULE kernel32 = LoadLibrary ("kernel32.dll");

  if (kernel32 != NULL)

    {

# if _GL_WINDOWS_STAT_INODES == 2

      GetFileInformationByHandleExFunc =

        (GetFileInformationByHandleExFuncType) GetProcAddress (kernel32, "GetFileInformationByHandleEx");

# endif

      GetFinalPathNameByHandleFunc =

        (GetFinalPathNameByHandleFuncType) GetProcAddress (kernel32, "GetFinalPathNameByHandleA");

    }

  initialized = TRUE;

}

#else

# define GetFileInformationByHandleExFunc GetFileInformationByHandleEx

# define GetFinalPathNameByHandleFunc GetFinalPathNameByHandle

#endif

/* Converts a FILETIME to GMT time since 1970-01-01 00:00:00.  */

#if _GL_WINDOWS_STAT_TIMESPEC

struct timespec

_gl_convert_FILETIME_to_timespec (const FILETIME *ft)

{

  struct timespec result;

  /* FILETIME: <https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ns-minwinbase-filetime> */

  unsigned long long since_1601 =

    ((unsigned long long) ft->dwHighDateTime << 32)

    | (unsigned long long) ft->dwLowDateTime;

  if (since_1601 == 0)

    {

      result.tv_sec = 0;

      result.tv_nsec = 0;

    }

  else

    {

      /* Between 1601-01-01 and 1970-01-01 there were 280 normal years and 89

         leap years, in total 134774 days.  */

      unsigned long long since_1970 =

        since_1601 - (unsigned long long) 134774 * (unsigned long long) 86400 * (unsigned long long) 10000000;

      result.tv_sec = since_1970 / (unsigned long long) 10000000;

      result.tv_nsec = (unsigned long) (since_1970 % (unsigned long long) 10000000) * 100;

    }

  return result;

}

#else

time_t

_gl_convert_FILETIME_to_POSIX (const FILETIME *ft)

{

  /* FILETIME: <https://docs.microsoft.com/en-us/windows/desktop/api/minwinbase/ns-minwinbase-filetime> */

  unsigned long long since_1601 =

    ((unsigned long long) ft->dwHighDateTime << 32)

    | (unsigned long long) ft->dwLowDateTime;

  if (since_1601 == 0)

    return 0;

  else

    {

      /* Between 1601-01-01 and 1970-01-01 there were 280 normal years and 89

         leap years, in total 134774 days.  */

      unsigned long long since_1970 =

        since_1601 - (unsigned long long) 134774 * (unsigned long long) 86400 * (unsigned long long) 10000000;

      return since_1970 / (unsigned long long) 10000000;

    }

}

#endif

/* Fill *BUF with information about the file designated by H.

   PATH is the file name, if known, otherwise NULL.

   Return 0 if successful, or -1 with errno set upon failure.  */

int

_gl_fstat_by_handle (HANDLE h, const char *path, struct stat *buf)

{

  /* GetFileType

     <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfiletype> */

  DWORD type = GetFileType (h);

  if (type == FILE_TYPE_DISK)

    {

#if !(_WIN32_WINNT >= _WIN32_WINNT_VISTA)

      if (!initialized)

        initialize ();

#endif

      /* st_mode can be determined through

         GetFileAttributesEx

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileattributesexa>

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_win32_file_attribute_data>

         or through

         GetFileInformationByHandle

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>

         or through

         GetFileInformationByHandleEx with argument FileBasicInfo

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_basic_info>

         The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */

      BY_HANDLE_FILE_INFORMATION info;

      if (! GetFileInformationByHandle (h, &info))

        goto failed;

      /* Test for error conditions before starting to fill *buf.  */

      if (sizeof (buf->st_size) <= 4 && info.nFileSizeHigh > 0)

        {

          errno = EOVERFLOW;

          return -1;

        }

#if _GL_WINDOWS_STAT_INODES

      /* st_ino can be determined through

         GetFileInformationByHandle

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>

         as 64 bits, or through

         GetFileInformationByHandleEx with argument FileIdInfo

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_id_info>

         as 128 bits.

         The latter requires -D_WIN32_WINNT=_WIN32_WINNT_WIN8 or higher.  */

      /* Experiments show that GetFileInformationByHandleEx does not provide

         much more information than GetFileInformationByHandle:

           * The dwVolumeSerialNumber from GetFileInformationByHandle is equal

             to the low 32 bits of the 64-bit VolumeSerialNumber from

             GetFileInformationByHandleEx, and is apparently sufficient for

             identifying the device.

           * The nFileIndex from GetFileInformationByHandle is equal to the low

             64 bits of the 128-bit FileId from GetFileInformationByHandleEx,

             and the high 64 bits of this 128-bit FileId are zero.

           * On a FAT file system, GetFileInformationByHandleEx fails with error

             ERROR_INVALID_PARAMETER, whereas GetFileInformationByHandle

             succeeds.

           * On a CIFS/SMB file system, GetFileInformationByHandleEx fails with

             error ERROR_INVALID_LEVEL, whereas GetFileInformationByHandle

             succeeds.  */

# if _GL_WINDOWS_STAT_INODES == 2

      if (GetFileInformationByHandleExFunc != NULL)

        {

          FILE_ID_INFO id;

          if (GetFileInformationByHandleExFunc (h, FileIdInfo, &id, sizeof (id)))

            {

              buf->st_dev = id.VolumeSerialNumber;

              verify (sizeof (ino_t) == sizeof (id.FileId));

              memcpy (&buf->st_ino, &id.FileId, sizeof (ino_t));

              goto ino_done;

            }

          else

            {

              switch (GetLastError ())

                {

                case ERROR_INVALID_PARAMETER: /* older Windows version, or FAT */

                case ERROR_INVALID_LEVEL: /* CIFS/SMB file system */

                  goto fallback;

                default:

                  goto failed;

                }

            }

        }

     fallback: ;

      /* Fallback for older Windows versions.  */

      buf->st_dev = info.dwVolumeSerialNumber;

      buf->st_ino._gl_ino[0] = ((ULONGLONG) info.nFileIndexHigh << 32) | (ULONGLONG) info.nFileIndexLow;

      buf->st_ino._gl_ino[1] = 0;

     ino_done: ;

# else /* _GL_WINDOWS_STAT_INODES == 1 */

      buf->st_dev = info.dwVolumeSerialNumber;

      buf->st_ino = ((ULONGLONG) info.nFileIndexHigh << 32) | (ULONGLONG) info.nFileIndexLow;

# endif

#else

      /* st_ino is not wide enough for identifying a file on a device.

         Without st_ino, st_dev is pointless.  */

      buf->st_dev = 0;

      buf->st_ino = 0;

#endif

      /* st_mode.  */

      unsigned int mode =

        /* XXX How to handle FILE_ATTRIBUTE_REPARSE_POINT ?  */

        ((info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) ? _S_IFDIR | S_IEXEC_UGO : _S_IFREG)

        | S_IREAD_UGO

        | ((info.dwFileAttributes & FILE_ATTRIBUTE_READONLY) ? 0 : S_IWRITE_UGO);

      if (!(info.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY))

        {

          /* Determine whether the file is executable by looking at the file

             name suffix.

             If the file name is already known, use it. Otherwise, for

             non-empty files, it can be determined through

             GetFinalPathNameByHandle

             <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfinalpathnamebyhandlea>

             or through

             GetFileInformationByHandleEx with argument FileNameInfo

             <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>

             <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_name_info>

             Both require -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */

          if (info.nFileSizeHigh > 0 || info.nFileSizeLow > 0)

            {

              char fpath[PATH_MAX];

              if (path != NULL

                  || (GetFinalPathNameByHandleFunc != NULL

                      && GetFinalPathNameByHandleFunc (h, fpath, sizeof (fpath), VOLUME_NAME_NONE)

                         < sizeof (fpath)

                      && (path = fpath, 1)))

                {

                  const char *last_dot = NULL;

                  const char *p;

                  for (p = path; *p != '\0'; p++)

                    if (*p == '.')

                      last_dot = p;

                  if (last_dot != NULL)

                    {

                      const char *suffix = last_dot + 1;

                      if (_stricmp (suffix, "exe") == 0

                          || _stricmp (suffix, "bat") == 0

                          || _stricmp (suffix, "cmd") == 0

                          || _stricmp (suffix, "com") == 0)

                        mode |= S_IEXEC_UGO;

                    }

                }

              else

                /* Cannot determine file name.  Pretend that it is executable.  */

                mode |= S_IEXEC_UGO;

            }

        }

      buf->st_mode = mode;

      /* st_nlink can be determined through

         GetFileInformationByHandle

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>

         or through

         GetFileInformationByHandleEx with argument FileStandardInfo

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_standard_info>

         The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */

      buf->st_nlink = (info.nNumberOfLinks > SHRT_MAX ? SHRT_MAX : info.nNumberOfLinks);

      /* There's no easy way to map the Windows SID concept to an integer.  */

      buf->st_uid = 0;

      buf->st_gid = 0;

      /* st_rdev is irrelevant for normal files and directories.  */

      buf->st_rdev = 0;

      /* st_size can be determined through

         GetFileSizeEx

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfilesizeex>

         or through

         GetFileAttributesEx

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileattributesexa>

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_win32_file_attribute_data>

         or through

         GetFileInformationByHandle

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>

         or through

         GetFileInformationByHandleEx with argument FileStandardInfo

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_standard_info>

         The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */

      if (sizeof (buf->st_size) <= 4)

        /* Range check already done above.  */

        buf->st_size = info.nFileSizeLow;

      else

        buf->st_size = ((long long) info.nFileSizeHigh << 32) | (long long) info.nFileSizeLow;

      /* st_atime, st_mtime, st_ctime can be determined through

         GetFileTime

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfiletime>

         or through

         GetFileAttributesEx

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileattributesexa>

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_win32_file_attribute_data>

         or through

         GetFileInformationByHandle

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/nf-fileapi-getfileinformationbyhandle>

         <https://docs.microsoft.com/en-us/windows/desktop/api/fileapi/ns-fileapi-_by_handle_file_information>

         or through

         GetFileInformationByHandleEx with argument FileBasicInfo

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/nf-winbase-getfileinformationbyhandleex>

         <https://docs.microsoft.com/en-us/windows/desktop/api/winbase/ns-winbase-_file_basic_info>

         The latter requires -D_WIN32_WINNT=_WIN32_WINNT_VISTA or higher.  */

#if _GL_WINDOWS_STAT_TIMESPEC

      buf->st_atim = _gl_convert_FILETIME_to_timespec (&info.ftLastAccessTime);

      buf->st_mtim = _gl_convert_FILETIME_to_timespec (&info.ftLastWriteTime);

      buf->st_ctim = _gl_convert_FILETIME_to_timespec (&info.ftCreationTime);

#else

      buf->st_atime = _gl_convert_FILETIME_to_POSIX (&info.ftLastAccessTime);

      buf->st_mtime = _gl_convert_FILETIME_to_POSIX (&info.ftLastWriteTime);

      buf->st_ctime = _gl_convert_FILETIME_to_POSIX (&info.ftCreationTime);

#endif

      return 0;

    }

  else if (type == FILE_TYPE_CHAR || type == FILE_TYPE_PIPE)

    {

      buf->st_dev = 0;

#if _GL_WINDOWS_STAT_INODES == 2

      buf->st_ino._gl_ino[0] = buf->st_ino._gl_ino[1] = 0;

#else

      buf->st_ino = 0;

#endif

      buf->st_mode = (type == FILE_TYPE_PIPE ? _S_IFIFO : _S_IFCHR);

      buf->st_nlink = 1;

      buf->st_uid = 0;

      buf->st_gid = 0;

      buf->st_rdev = 0;

      if (type == FILE_TYPE_PIPE)

        {

          /* PeekNamedPipe

             <https://msdn.microsoft.com/en-us/library/aa365779.aspx> */

          DWORD bytes_available;

          if (PeekNamedPipe (h, NULL, 0, NULL, &bytes_available, NULL))

            buf->st_size = bytes_available;

          else

            buf->st_size = 0;

        }

      else

        buf->st_size = 0;

#if _GL_WINDOWS_STAT_TIMESPEC

      buf->st_atim.tv_sec = 0; buf->st_atim.tv_nsec = 0;

      buf->st_mtim.tv_sec = 0; buf->st_mtim.tv_nsec = 0;

      buf->st_ctim.tv_sec = 0; buf->st_ctim.tv_nsec = 0;

#else

      buf->st_atime = 0;

      buf->st_mtime = 0;

      buf->st_ctime = 0;

#endif

      return 0;

    }

  else

    {

      errno = ENOENT;

      return -1;

    }

 failed:

  {

    DWORD error = GetLastError ();

    #if 0

    fprintf (stderr, "_gl_fstat_by_handle error 0x%x\n", (unsigned int) error);

    #endif

    switch (error)

      {

      case ERROR_ACCESS_DENIED:

      case ERROR_SHARING_VIOLATION:

        errno = EACCES;

        break;

      case ERROR_OUTOFMEMORY:

        errno = ENOMEM;

        break;

      case ERROR_WRITE_FAULT:

      case ERROR_READ_FAULT:

      case ERROR_GEN_FAILURE:

        errno = EIO;

        break;

      default:

        errno = EINVAL;

        break;

      }

    return -1;

  }

}

#else

/* This declaration is solely to ensure that after preprocessing

   this file is never empty.  */

typedef int dummy;

#endif