text: /* Copyright (c) Piotr Durlej
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are met:
   *
   * 1. Redistributions of source code must retain the above copyright notice,
   * this list of conditions and the following disclaimer.
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
   * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
   * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
   * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
   * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
   * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
   * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
   * POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include <xenus/mtab.h>
  #include <sys/mount.h>
  #include <unistd.h>
  #include <string.h>
  #include <fcntl.h>
  #include <stdio.h>
  #include <errno.h>
  
  static int mtfd = -1;
  
  static void clrm(char *dir)
  {
  	struct mtab mt;
  	ssize_t cnt;
  	
  	if (mtfd < 0)
  		mtfd = open("/etc/mtab", O_RDWR);
  	if (mtfd < 0)
  	{
  		if (errno != ENOENT)
  			perror("/etc/mtab");
  		return;
  	}
  	lseek(mtfd, 0, SEEK_SET);
  	
  	while (cnt = read(mtfd, &mt, sizeof mt), cnt == sizeof mt)
  		if (!strncmp(mt.path, dir, sizeof mt.path))
  		{
  			memset(&mt, 0, sizeof mt);
  			lseek(mtfd, -cnt, SEEK_CUR);
  			write(mtfd, &mt, sizeof mt);
  			return;
  		}
  }
  
  int main(int argc, char **argv)
  {
  	if (argc < 2)
  	{
  		fputs("umount dir\n", stderr);
  		return 1;
  	}
  	
  	if (umount(argv[1]))
  	{
  		perror(NULL);
  		return 1;
  	}
  	clrm(argv[1]);
  	return 0;
  }
  