[deliverable/binutils-gdb.git] / gold / ftruncate.c

/* ftruncate emulations that work on some System V's.
   This file is in the public domain.  */

/* Copyright (C) 2012-2016 Free Software Foundation, Inc.

   This file is part of gold.

   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, write to the Free Software
   Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
   MA 02110-1301, USA.  */

#include <config.h>

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

#include <sys/types.h>
#include <fcntl.h>

extern int ftruncate (int, off_t);

#ifdef F_CHSIZE

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

#else /* not F_CHSIZE */
# ifdef F_FREESP

/* By William Kucharski <kucharsk@netcom.com>.  */

#  include <sys/stat.h>
#  include <errno.h>

int
ftruncate (int fd, off_t length)
{
  struct flock fl;
  struct stat filebuf;

  if (fstat (fd, &filebuf) < 0)
    return -1;

  if (filebuf.st_size < length)
    {
      /* Extend file length. */
      if (lseek (fd, (length - 1), SEEK_SET) < 0)
	return -1;

      /* Write a "0" byte. */
      if (write (fd, "", 1) != 1)
	return -1;
    }
  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 */

      /* 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?  */

      if (fcntl (fd, F_FREESP, &fl) < 0)
	return -1;
    }

  return 0;
}

# else /* not F_CHSIZE nor F_FREESP */
#  if HAVE_CHSIZE                      /* native Windows, e.g. mingw */

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

#  else /* not F_CHSIZE nor F_FREESP nor HAVE_CHSIZE */

#   include <errno.h>

int
ftruncate (int fd, off_t length)
{
  errno = EIO;
  return -1;
}

#  endif /* not HAVE_CHSIZE */
# endif /* not F_FREESP */
#endif /* not F_CHSIZE */
Commit	Line	Data
9201d894 ILT	1	/* ftruncate emulations that work on some System V's.
	2	This file is in the public domain. */
	3
6f2750fe	4	/* Copyright (C) 2012-2016 Free Software Foundation, Inc.
5bf135a7 NC	5
	6	This file is part of gold.
	7
	8	This program is free software; you can redistribute it and/or modify
	9	it under the terms of the GNU General Public License as published by
	10	the Free Software Foundation; either version 3 of the License, or
	11	(at your option) any later version.
	12
	13	This program is distributed in the hope that it will be useful,
	14	but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	16	GNU General Public License for more details.
	17
	18	You should have received a copy of the GNU General Public License
	19	along with this program; if not, write to the Free Software
	20	Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston,
	21	MA 02110-1301, USA. */
	22
9201d894 ILT	23	#include <config.h>
	24
	25	/* Specification. */
	26	#include <unistd.h>
	27
	28	#include <sys/types.h>
	29	#include <fcntl.h>
	30
fd03461a ILT	31	extern int ftruncate (int, off_t);
fd03461a ILT	32
9201d894 ILT	33	#ifdef F_CHSIZE
	34
	35	int
	36	ftruncate (int fd, off_t length)
	37	{
	38	return fcntl (fd, F_CHSIZE, length);
	39	}
	40
	41	#else /* not F_CHSIZE */
	42	# ifdef F_FREESP
	43
	44	/* By William Kucharski <kucharsk@netcom.com>. */
	45
	46	# include <sys/stat.h>
	47	# include <errno.h>
	48
	49	int
	50	ftruncate (int fd, off_t length)
	51	{
	52	struct flock fl;
	53	struct stat filebuf;
	54
	55	if (fstat (fd, &filebuf) < 0)
	56	return -1;
	57
	58	if (filebuf.st_size < length)
	59	{
	60	/* Extend file length. */
	61	if (lseek (fd, (length - 1), SEEK_SET) < 0)
	62	return -1;
	63
	64	/* Write a "0" byte. */
	65	if (write (fd, "", 1) != 1)
	66	return -1;
	67	}
	68	else
	69	{
	70
	71	/* Truncate length. */
	72
	73	fl.l_whence = 0;
	74	fl.l_len = 0;
	75	fl.l_start = length;
	76	fl.l_type = F_WRLCK; /* write lock on file space */
	77
	78	/* This relies on the undocumented F_FREESP argument to fcntl,
	79	which truncates the file so that it ends at the position
	80	indicated by fl.l_start. Will minor miracles never cease? */
	81
	82	if (fcntl (fd, F_FREESP, &fl) < 0)
	83	return -1;
	84	}
	85
	86	return 0;
	87	}
	88
	89	# else /* not F_CHSIZE nor F_FREESP */
	90	# if HAVE_CHSIZE /* native Windows, e.g. mingw */
	91
	92	int
	93	ftruncate (int fd, off_t length)
	94	{
	95	return chsize (fd, length);
	96	}
97
98	# else /* not F_CHSIZE nor F_FREESP nor HAVE_CHSIZE */
99
100	# include <errno.h>
101
102	int
103	ftruncate (int fd, off_t length)
104	{
105	errno = EIO;
106	return -1;
107	}
108
109	# endif /* not HAVE_CHSIZE */
110	# endif /* not F_FREESP */
111	#endif /* not F_CHSIZE */