view lib/ftruncate.c @ 15727:144db791c6fa

Ensure EBADF returns for socket functions on mingw. * lib/accept.c (rpl_accept): Fail with error EBADF if the file descriptor is invalid. * lib/bind.c (rpl_bind): Likewise. * lib/connect.c (rpl_connect): Likewise. * lib/getpeername.c (rpl_getpeername): Likewise. * lib/getsockname.c (rpl_getsockname): Likewise. * lib/getsockopt.c (rpl_getsockopt): Likewise. * lib/listen.c (rpl_listen): Likewise. * lib/recv.c (rpl_recv): Likewise. * lib/recvfrom.c (rpl_recvfrom): Likewise. * lib/send.c (rpl_send): Likewise. * lib/sendto.c (rpl_sendto): Likewise. * lib/setsockopt.c (rpl_setsockopt): Likewise. * lib/shutdown.c (rpl_shutdown): Likewise.
author Bruno Haible <bruno@clisp.org>
date Wed, 21 Sep 2011 00:20:59 +0200
parents e8d2c6fc33ad
children 9f82d16d3139
line wrap: on
line source

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

#include <config.h>

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

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

#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 */