random32.c

linuxUNIX下跑的一套服务端程序

/* * 
 *  $Id: random32.c 20 2004-06-18 17:14:56Z federico $
 *  
 *  This file is part of NeMeSI
 *
 *  NeMeSI -- NEtwork MEdia Streamer I
 *
 *  Copyright (C) 2001 by
 *  	
 *  	Giampaolo "mancho" Mancini - [e-mail]
 *	Francesco "shawill" Varano - [e-mail]
 *
 *  NeMeSI 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.
 *
 *  NeMeSI 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 NeMeSI; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *  
 * */

/* From RFC 1889 */

#include <sys/time.h>
#include <sys/utsname.h>
#include <sys/types.h>
#include <unistd.h>
#include <time.h>
#include <fenice/md5global.h>
#include <fenice/md5.h>
#include <fenice/types.h>

static uint32 md_32(char *string, int length)
{
	MD5_CTX context;
	union {
		char c[16];
		uint32 x[4];
	} digest;
	uint32 r;
	int i;

	MD5Init(&context);
	MD5Update(&context, string, length);
	MD5Final((unsigned char *)&digest, &context);
	r=0;
	for (i=0; i<3; i++)
		r ^= digest.x[i];
	return r;
}

uint32 random32(int type)
{
	struct {
		int type;
		struct timeval tv;
		clock_t cpu;
		pid_t pid;
		uint32 hid;
		uid_t uid;
		gid_t gid;
		struct utsname name;
	} s;

	gettimeofday(&s.tv, NULL);
	uname(&s.name);
	s.type=type;
	s.cpu=clock();
	s.pid=getpid();
	s.hid=gethostid();
	s.uid=getuid();
	s.gid=getgid();

	return md_32((char *)&s, sizeof(s));
}