ftruncate.c

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Hash : 3f3d9b41
Author :
Date : 2012-04-14T23:27:45

Large File Support for native Windows platforms.

* m4/largefile.m4 (gl_LARGEFILE): New macro.
* modules/largefile (configure.ac): Require gl_LARGEFILE.

* lib/sys_types.in.h (off_t) [WINDOWS_64_BIT_OFF_T]: Define to a 64-bit
type.
* m4/sys_types_h.m4 (gl_SYS_TYPES_H): Set WINDOWS_64_BIT_OFF_T.
* modules/sys_types (Makefile.am): Substitute WINDOWS_64_BIT_OFF_T.
* doc/posix-headers/sys_types.texi: Mention the effect of the
'largefile' module.

* lib/fcntl.in.h: Add comments about off_t.
* modules/fcntl-h (Depends-on): Add sys_types.

* lib/unistd.in.h [WINDOWS_64_BIT_OFF_T]: Include <sys/types.h>.
(ftruncate): Replace it if REPLACE_FTRUNCATE is 1.
* m4/unistd_h.m4 (gl_UNISTD_H): Require gl_SYS_TYPES_H.
(gl_UNISTD_H_DEFAULTS): Initialize REPLACE_FTRUNCATE.
* modules/unistd (Depends-on): Add sys_types.
(Makefile.am): Substitute WINDOWS_64_BIT_OFF_T, REPLACE_FTRUNCATE.

* lib/lseek.c (rpl_lseek) [_GL_WINDOWS_64_BIT_OFF_T]: Use _lseeki64
instead of lseek.
* m4/lseek.m4 (gl_FUNC_LSEEK): Require gl_SYS_TYPES_H. Set
REPLACE_LSEEK if WINDOWS_64_BIT_OFF_T is 1.
* modules/lseek (Depends-on): Add sys_types.

* lib/ftruncate.c: Put under GPLv3+. Include <windows.h>,
msvc-nothrow.h.
(SetFileSize): New function.
(ftruncate) [_GL_WINDOWS_64_BIT_OFF_T]: New implementation.
* m4/ftruncate.m4 (gl_FUNC_FTRUNCATE): Set REPLACE_FTRUNCATE on Windows
if Large File Support is requested.
* modules/ftruncate (configure.ac): Consider REPLACE_FTRUNCATE.
(Depends-on): Add sys_types, msvc-nothrow. Update conditions.

* lib/stdio.in.h: Add comments about off_t.
* modules/stdio (Depends-on): Add sys_types.

* lib/ftello.c [_GL_WINDOWS_64_BIT_OFF_T]: Use _ftelli64 or ftello64
instead of ftello.
* m4/ftello.m4 (gl_FUNC_FTELLO): Require gl_SYS_TYPES_H. Set
REPLACE_FTELLO if WINDOWS_64_BIT_OFF_T is 1.
(gl_PREREQ_FTELLO): New macro.
* modules/ftello (Depends-on): Add sys_types.
(configure.ac): Incoke gl_PREREQ_FTELLO.

* lib/fseeko.c [_GL_WINDOWS_64_BIT_OFF_T]: Use _fseeki64 or fseeko64
instead of fseeko.
* m4/fseeko.m4 (gl_FUNC_FSEEKO): Require gl_SYS_TYPES_H. Set
REPLACE_FSEEKO if WINDOWS_64_BIT_OFF_T is 1.
(gl_PREREQ_FSEEKO): New macro.
* modules/fseeko (Depends-on): Add sys_types.
(configure.ac): Invoke gl_PREREQ_FSEEKO.

* lib/sys_stat.in.h: Add comments about off_t.
(stat, fstat) [WINDOWS_64_BIT_ST_SIZE]: Define to variants that use a
64-bit integer for st_size in 'struct stat'.
* m4/sys_stat_h.m4 (gl_HEADER_SYS_STAT_H): Set WINDOWS_64_BIT_ST_SIZE.
Define _GL_WINDOWS_64_BIT_ST_SIZE.
* modules/sys_stat (Depends-on): Add sys_types.
(Makefile.am): Substitute WINDOWS_64_BIT_ST_SIZE.

* lib/stat.c (stat) [_GL_WINDOWS_64_BIT_ST_SIZE]: Define to _stati64
instead of stat or _stat.

* lib/fstat.c [_GL_WINDOWS_64_BIT_ST_SIZE]: Use _fstati64 and
'struct _stati64' instead of fstat and 'struct stat'.
* m4/fstat.m4 (gl_FUNC_FSTAT): Require gl_HEADER_SYS_STAT_H. Set
REPLACE_FSTAT if WINDOWS_64_BIT_ST_SIZE is 1.

Reported by Ray Satiro <raysatiro@yahoo.com>.

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lib/ftruncate.c

/* ftruncate emulations for native Windows.
   Copyright (C) 1992-2012 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, 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 <http://www.gnu.org/licenses/>.  */

#include <config.h>

/* Specification.  */
#include <unistd.h>

#if HAVE_CHSIZE
/* A native Windows platform.  */

# include <errno.h>

# if _GL_WINDOWS_64_BIT_OFF_T

/* Large File Support: off_t is 64-bit, but chsize() takes only a 32-bit
   argument.  So, define a 64-bit safe SetFileSize function ourselves.  */

/* Ensure that <windows.h> declares GetFileSizeEx.  */
#  undef _WIN32_WINNT
#  define _WIN32_WINNT 0x500

/* Get declarations of the native Windows API functions.  */
#  define WIN32_LEAN_AND_MEAN
#  include <windows.h>

/* Get _get_osfhandle.  */
#  include "msvc-nothrow.h"

static BOOL
SetFileSize (HANDLE h, LONGLONG size)
{
  LARGE_INTEGER old_size;

  if (!GetFileSizeEx (h, &old_size))
    return FALSE;

  if (size != old_size.QuadPart)
    {
      /* Duplicate the handle, so we are free to modify its file position.  */
      HANDLE curr_process = GetCurrentProcess ();
      HANDLE tmph;

      if (!DuplicateHandle (curr_process,           /* SourceProcessHandle */
                            h,                      /* SourceHandle */
                            curr_process,           /* TargetProcessHandle */
                            (PHANDLE) &tmph,        /* TargetHandle */
                            (DWORD) 0,              /* DesiredAccess */
                            FALSE,                  /* InheritHandle */
                            DUPLICATE_SAME_ACCESS)) /* Options */
        return FALSE;

      if (size < old_size.QuadPart)
        {
          /* Reduce the size.  */
          LONG size_hi = (LONG) (size >> 32);
          if (SetFilePointer (tmph, (LONG) size, &size_hi, FILE_BEGIN)
              == INVALID_SET_FILE_POINTER
              && GetLastError() != NO_ERROR)
            {
              CloseHandle (tmph);
              return FALSE;
            }
          if (!SetEndOfFile (tmph))
            {
              CloseHandle (tmph);
              return FALSE;
            }
        }
      else
        {
          /* Increase the size by adding zero bytes at the end.  */
          static char zero_bytes[1024];
          LONG pos_hi = 0;
          LONG pos_lo = SetFilePointer (tmph, (LONG) 0, &pos_hi, FILE_END);
          LONGLONG pos;
          if (pos_lo == INVALID_SET_FILE_POINTER
              && GetLastError() != NO_ERROR)
            {
              CloseHandle (tmph);
              return FALSE;
            }
          pos = ((LONGLONG) pos_hi << 32) | (ULONGLONG) (ULONG) pos_lo;
          while (pos < size)
            {
              DWORD written;
              LONGLONG count = size - pos;
              if (count > sizeof (zero_bytes))
                count = sizeof (zero_bytes);
              if (!WriteFile (tmph, zero_bytes, (DWORD) count, &written, NULL)
                  || written == 0)
                {
                  CloseHandle (tmph);
                  return FALSE;
                }
              pos += (ULONGLONG) (ULONG) written;
            }
        }
      /* Close the handle.  */
      CloseHandle (tmph);
    }
  return TRUE;
}

int
ftruncate (int fd, off_t length)
{
  HANDLE handle = (HANDLE) _get_osfhandle (fd);

  if (handle == INVALID_HANDLE_VALUE)
    {
      errno = EBADF;
      return -1;
    }
  if (length < 0)
    {
      errno = EINVAL;
      return -1;
    }
  if (!SetFileSize (handle, length))
    {
      switch (GetLastError ())
        {
        case ERROR_ACCESS_DENIED:
          errno = EACCES;
          break;
        case ERROR_HANDLE_DISK_FULL:
        case ERROR_DISK_FULL:
        case ERROR_DISK_TOO_FRAGMENTED:
          errno = ENOSPC;
          break;
        default:
          errno = EIO;
          break;
        }
      return -1;
    }
  return 0;
}

# else

#  include <io.h>

#  if HAVE_MSVC_INVALID_PARAMETER_HANDLER
#   include "msvc-inval.h"
static inline int
chsize_nothrow (int fd, long length)
{
  int result;

  TRY_MSVC_INVAL
    {
      result = chsize (fd, length);
    }
  CATCH_MSVC_INVAL
    {
      result = -1;
      errno = EBADF;
    }
  DONE_MSVC_INVAL;

  return result;
}
#   define chsize chsize_nothrow
#  endif

int
ftruncate (int fd, off_t length)
{
  return chsize (fd, length);
}

# endif
#endif

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