gl/tests/ftruncate.c

   1 /* ftruncate emulations for native Windows.
   2    Copyright (C) 1992-2012 Free Software Foundation, Inc.
   3
   4    This program is free software; you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation; either version 3, or (at your option)
   7    any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License along
  15    with this program; if not, see <http://www.gnu.org/licenses/>.  */
  16
  17 #include <config.h>
  18
  19 /* Specification.  */
  20 #include <unistd.h>
  21
  22 #if HAVE_CHSIZE
  23 /* A native Windows platform.  */
  24
  25 # include <errno.h>
  26
  27 # if _GL_WINDOWS_64_BIT_OFF_T
  28
  29 /* Large File Support: off_t is 64-bit, but chsize() takes only a 32-bit
  30    argument.  So, define a 64-bit safe SetFileSize function ourselves.  */
  31
  32 /* Ensure that <windows.h> declares GetFileSizeEx.  */
  33 #  undef _WIN32_WINNT
  34 #  define _WIN32_WINNT 0x500
  35
  36 /* Get declarations of the native Windows API functions.  */
  37 #  define WIN32_LEAN_AND_MEAN
  38 #  include <windows.h>
  39
  40 /* Get _get_osfhandle.  */
  41 #  include "msvc-nothrow.h"
  42
  43 static BOOL
  44 SetFileSize (HANDLE h, LONGLONG size)
  45 {
  46   LARGE_INTEGER old_size;
  47
  48   if (!GetFileSizeEx (h, &old_size))
  49     return FALSE;
  50
  51   if (size != old_size.QuadPart)
  52     {
  53       /* Duplicate the handle, so we are free to modify its file position.  */
  54       HANDLE curr_process = GetCurrentProcess ();
  55       HANDLE tmph;
  56
  57       if (!DuplicateHandle (curr_process,           /* SourceProcessHandle */
  58                             h,                      /* SourceHandle */
  59                             curr_process,           /* TargetProcessHandle */
  60                             (PHANDLE) &tmph,        /* TargetHandle */
  61                             (DWORD) 0,              /* DesiredAccess */
  62                             FALSE,                  /* InheritHandle */
  63                             DUPLICATE_SAME_ACCESS)) /* Options */
  64         return FALSE;
  65
  66       if (size < old_size.QuadPart)
  67         {
  68           /* Reduce the size.  */
  69           LONG size_hi = (LONG) (size >> 32);
  70           if (SetFilePointer (tmph, (LONG) size, &size_hi, FILE_BEGIN)
  71               == INVALID_SET_FILE_POINTER
  72               && GetLastError() != NO_ERROR)
  73             {
  74               CloseHandle (tmph);
  75               return FALSE;
  76             }
  77           if (!SetEndOfFile (tmph))
  78             {
  79               CloseHandle (tmph);
  80               return FALSE;
  81             }
  82         }
  83       else
  84         {
  85           /* Increase the size by adding zero bytes at the end.  */
  86           static char zero_bytes[1024];
  87           LONG pos_hi = 0;
  88           LONG pos_lo = SetFilePointer (tmph, (LONG) 0, &pos_hi, FILE_END);
  89           LONGLONG pos;
  90           if (pos_lo == INVALID_SET_FILE_POINTER
  91               && GetLastError() != NO_ERROR)
  92             {
  93               CloseHandle (tmph);
  94               return FALSE;
  95             }
  96           pos = ((LONGLONG) pos_hi << 32) | (ULONGLONG) (ULONG) pos_lo;
  97           while (pos < size)
  98             {
  99               DWORD written;
 100               LONGLONG count = size - pos;
 101               if (count > sizeof (zero_bytes))
 102                 count = sizeof (zero_bytes);
 103               if (!WriteFile (tmph, zero_bytes, (DWORD) count, &written, NULL)
 104                   || written == 0)
 105                 {
 106                   CloseHandle (tmph);
 107                   return FALSE;
 108                 }
 109               pos += (ULONGLONG) (ULONG) written;
 110             }
 111         }
 112       /* Close the handle.  */
 113       CloseHandle (tmph);
 114     }
 115   return TRUE;
 116 }
 117
 118 int
 119 ftruncate (int fd, off_t length)
 120 {
 121   HANDLE handle = (HANDLE) _get_osfhandle (fd);
 122
 123   if (handle == INVALID_HANDLE_VALUE)
 124     {
 125       errno = EBADF;
 126       return -1;
 127     }
 128   if (length < 0)
 129     {
 130       errno = EINVAL;
 131       return -1;
 132     }
 133   if (!SetFileSize (handle, length))
 134     {
 135       switch (GetLastError ())
 136         {
 137         case ERROR_ACCESS_DENIED:
 138           errno = EACCES;
 139           break;
 140         case ERROR_HANDLE_DISK_FULL:
 141         case ERROR_DISK_FULL:
 142         case ERROR_DISK_TOO_FRAGMENTED:
 143           errno = ENOSPC;
 144           break;
 145         default:
 146           errno = EIO;
 147           break;
 148         }
 149       return -1;
 150     }
 151   return 0;
 152 }
 153
 154 # else
 155
 156 #  include <io.h>
 157
 158 #  if HAVE_MSVC_INVALID_PARAMETER_HANDLER
 159 #   include "msvc-inval.h"
 160 static inline int
 161 chsize_nothrow (int fd, long length)
 162 {
 163   int result;
 164
 165   TRY_MSVC_INVAL
 166     {
 167       result = chsize (fd, length);
 168     }
 169   CATCH_MSVC_INVAL
 170     {
 171       result = -1;
 172       errno = EBADF;
 173     }
 174   DONE_MSVC_INVAL;
 175
 176   return result;
 177 }
 178 #   define chsize chsize_nothrow
 179 #  endif
 180
 181 int
 182 ftruncate (int fd, off_t length)
 183 {
 184   return chsize (fd, length);
 185 }
 186
 187 # endif
 188 #endif