#ident "$Id$"
/* ----------------------------------------------------------------------- *
 *   
 *   Copyright 2001 H. Peter Anvin - All Rights Reserved
 *
 *   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, Inc., 675 Mass Ave, Cambridge MA 02139,
 *   USA; either version 2 of the License, or (at your option) any later
 *   version; incorporated herein by reference.
 *
 * ----------------------------------------------------------------------- */

/*
 * killramdisk.c
 *
 * This utility opens a ramdisk device (/dev/ram*) and attempts
 * to free its contents.
 */

#include <stdio.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/mount.h>
#include <string.h>

#ifndef MAJOR
# define MAJOR(X)	((X) >> 8)
#endif

const char *program;

void fail(const char *rdname)
{
  const char *err = strerror(errno);
  fprintf(stderr, "%s: %s: %s\n", program, rdname, err);
  exit(1);
}

int main(int argc, char *argv[])
{
  int i, rd;
  const char *rdname;
  struct stat st;

  program = argv[0];

  for ( i = 1 ; i < argc ; i++ ) {
    rdname = argv[i];

    rd = open(rdname, O_RDWR);
    if ( rd < 0 )
      fail(rdname);
    if ( fstat(rd, &st) < 0 )
      fail(rdname);
    /* There should be a cleaner way to test for this! */
    if ( !S_ISBLK(st.st_mode) || MAJOR(st.st_rdev) != 1 ) {
      fprintf(stderr, "%s: %s: Not a ramdisk device\n",
	      program, rdname);
      exit(1);
    }

    if ( ioctl(rd, BLKFLSBUF, 0) < 0 ) {
      fail(rdname);
    }

    close(rd);
  }

  return 0;
}