-/* ftruncate emulations that work on some System V's.
- This file is in the public domain. */
+/* ftruncate emulations for native Windows.
+ Copyright (C) 1992-2014 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>
-#include <sys/types.h>
-#include <fcntl.h>
+#if HAVE_CHSIZE
+/* A native Windows platform. */
-#ifdef F_CHSIZE
+# include <errno.h>
-int
-ftruncate (int fd, off_t length)
-{
- return fcntl (fd, F_CHSIZE, length);
-}
+# if _GL_WINDOWS_64_BIT_OFF_T
-#else /* not F_CHSIZE */
-# ifdef F_FREESP
+/* 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. */
-/* By William Kucharski <kucharsk@netcom.com>. */
+/* Ensure that <windows.h> declares GetFileSizeEx. */
+# undef _WIN32_WINNT
+# define _WIN32_WINNT 0x500
-# include <sys/stat.h>
-# include <errno.h>
+/* Get declarations of the native Windows API functions. */
+# define WIN32_LEAN_AND_MEAN
+# include <windows.h>
-int
-ftruncate (int fd, off_t length)
+/* Get _get_osfhandle. */
+# include "msvc-nothrow.h"
+
+static BOOL
+SetFileSize (HANDLE h, LONGLONG size)
{
- struct flock fl;
- struct stat filebuf;
+ LARGE_INTEGER old_size;
- if (fstat (fd, &filebuf) < 0)
- return -1;
+ if (!GetFileSizeEx (h, &old_size))
+ return FALSE;
- if (filebuf.st_size < length)
+ if (size != old_size.QuadPart)
{
- /* Extend file length. */
- if (lseek (fd, (length - 1), SEEK_SET) < 0)
- return -1;
-
- /* Write a "0" byte. */
- if (write (fd, "", 1) != 1)
- return -1;
+ /* 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);
}
- else
- {
-
- /* Truncate length. */
-
- fl.l_whence = 0;
- fl.l_len = 0;
- fl.l_start = length;
- fl.l_type = F_WRLCK; /* write lock on file space */
+ return TRUE;
+}
- /* This relies on the *undocumented* F_FREESP argument to fcntl,
- which truncates the file so that it ends at the position
- indicated by fl.l_start. Will minor miracles never cease? */
+int
+ftruncate (int fd, off_t length)
+{
+ HANDLE handle = (HANDLE) _get_osfhandle (fd);
- if (fcntl (fd, F_FREESP, &fl) < 0)
- return -1;
+ 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 /* not F_CHSIZE nor F_FREESP */
-# if HAVE_CHSIZE /* native Windows, e.g. mingw */
+# else
-int
-ftruncate (int fd, off_t length)
+# include <io.h>
+
+# if HAVE_MSVC_INVALID_PARAMETER_HANDLER
+# include "msvc-inval.h"
+static int
+chsize_nothrow (int fd, long length)
{
- return chsize (fd, length);
-}
+ int result;
-# else /* not F_CHSIZE nor F_FREESP nor HAVE_CHSIZE */
+ TRY_MSVC_INVAL
+ {
+ result = chsize (fd, length);
+ }
+ CATCH_MSVC_INVAL
+ {
+ result = -1;
+ errno = EBADF;
+ }
+ DONE_MSVC_INVAL;
-# include <errno.h>
+ return result;
+}
+# define chsize chsize_nothrow
+# endif
int
ftruncate (int fd, off_t length)
{
- errno = EIO;
- return -1;
+ return chsize (fd, length);
}
-# endif /* not HAVE_CHSIZE */
-# endif /* not F_FREESP */
-#endif /* not F_CHSIZE */
+# endif
+#endif
projects / gnulib.git / blobdiff