fstatvfs.c

/* Copyright (C) 1998 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Ulrich Drepper <drepper@cygnus.com>, 1998.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public License as
   published by the Free Software Foundation; either version 2 of the
   License, or (at your option) any later version.

   The GNU C Library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public
   License along with the GNU C Library; see the file COPYING.LIB.  If not,
   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
   Boston, MA 02111-1307, USA.  */

#include <errno.h>
#include <mntent.h>
#include <paths.h>
#include <string.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/statfs.h>
#include <sys/statvfs.h>


int
fstatvfs (int fd, struct statvfs *buf)
{
  struct statfs fsbuf;
  struct stat st;

  /* Get as much information as possible from the system.  */
  if (__fstatfs (fd, &fsbuf) < 0)
    return -1;

  /* Now fill in the fields we have information for.  */
  buf->f_bsize = fsbuf.f_bsize;
  buf->f_blocks = fsbuf.f_blocks;
  buf->f_bfree = fsbuf.f_bfree;
  buf->f_bavail = fsbuf.f_bavail;
  buf->f_files = fsbuf.f_files;
  buf->f_ffree = fsbuf.f_ffree;
  buf->f_fsid = fsbuf.f_fsid;
  buf->f_namemax = fsbuf.f_namelen;
  memset (buf->f_spare, '\0', 6 * sizeof (int));

  /* What remains to do is to fill the fields f_frsize, f_favail,
     and f_flag.  */

  /* Linux does not support f_frsize, so set it to zero.  */
  buf->f_frsize = 0;

  /* XXX I have no idea how to compute f_favail.  Any idea???  */
  buf->f_favail = buf->f_ffree;

  /* Determining the flags is tricky.  We have to read /proc/mounts or
     the /etc/mtab file and search for the entry which matches the given
     file.  The way we can test for matching filesystem is using the
     device number.  */
  buf->f_flag = 0;
  if (fstat (fd, &st) >= 0)
    {
      int save_errno = errno;
      struct mntent mntbuf;
      FILE *mtab;

      mtab = __setmntent ("/proc/mounts", "r");
      if (mtab == NULL)
	mtab = __setmntent (_PATH_MOUNTED, "r");

      if (mtab != NULL)
	{
	  char tmpbuf[1024];

	  while (__getmntent_r (mtab, &mntbuf, tmpbuf, sizeof (tmpbuf)))
	    {
	      struct stat fsst;

	      /* Find out about the device the current entry is for.  */
	      if (stat (mntbuf.mnt_dir, &fsst) >= 0
		  && st.st_dev == fsst.st_dev)
		{
		  /* Bingo, we found the entry for the device FD is on.
		     Now interpret the option string.  */
		  char *cp = mntbuf.mnt_opts;
		  char *opt;

		  while ((opt = strsep (&cp, ",")) != NULL)
		    if (strcmp (opt, "ro") == 0)
		      buf->f_flag |= ST_RDONLY;
		    else if (strcmp (opt, "nosuid") == 0)
		      buf->f_flag |= ST_NOSUID;
		    else if (strcmp (opt, "noexec") == 0)
		      buf->f_flag |= ST_NOEXEC;
		    else if (strcmp (opt, "nodev") == 0)
		      buf->f_flag |= ST_NODEV;
		    else if (strcmp (opt, "sync") == 0)
		      buf->f_flag |= ST_SYNCHRONOUS;
		    else if (strcmp (opt, "mand") == 0)
		      buf->f_flag |= ST_MANDLOCK;
		    else if (strcmp (opt, "noatime") == 0)
		      buf->f_flag |= ST_NOATIME;
		    else if (strcmp (opt, "nodiratime") == 0)
		      buf->f_flag |= ST_NODIRATIME;

		  /* We can stop looking for more entries.  */
		  break;
		}
	    }

	  /* Close the file.  */
	  __endmntent (mtab);
	}

      __set_errno (save_errno);
    }

  /* We signal success if the statfs call succeeded.  */
  return 0;
}