freeramdisk.c

这是一个SIGMA方案的PMP播放器的UCLINUX程序,可播放DVD,VCD,CD MP3...有很好的参考价值.

/* vi: set sw=4 ts=4: */
/*
 * freeramdisk implementation for busybox
 *
 * Copyright (C) 2000 and written by Emanuele Caratti <[e-mail]>
 * Adjusted a bit by Erik Andersen <[e-mail]>
 *
 * 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 2 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <errno.h>
#include <stdlib.h>
#include "busybox.h"


/* From linux/fs.h */
#define BLKFLSBUF  _IO(0x12,97)	/* flush buffer cache */

extern int
freeramdisk_main(int argc, char **argv)
{
	FILE *f;

	if (argc != 2 || *argv[1] == '-') {
		show_usage();
	}

	f = xfopen(argv[1], "r+");
	
	if (ioctl(fileno(f), BLKFLSBUF) < 0) {
		perror_msg_and_die("failed ioctl on %s", argv[1]);
	}
	/* Don't bother closing.  Exit does
	 * that, so we can save a few bytes */
	/* close(f); */
	return EXIT_SUCCESS;
}

/*
Local Variables:
c-file-style: "linux"
c-basic-offset: 4
tab-width: 4
End:
*/