1 60d3db8e 2004-04-21 devnull #include <u.h>
 2 60d3db8e 2004-04-21 devnull #include <libc.h>
 3 60d3db8e 2004-04-21 devnull 
 4 60d3db8e 2004-04-21 devnull ulong
 5 60d3db8e 2004-04-21 devnull truerand(void)
 6 60d3db8e 2004-04-21 devnull {
 7 60d3db8e 2004-04-21 devnull 	int i, n;
 8 60d3db8e 2004-04-21 devnull 	uchar buf[sizeof(ulong)];
 9 60d3db8e 2004-04-21 devnull 	static int randfd = -1;
10 3a6c348f 2005-09-19 devnull 	static char *randfile;
11 60d3db8e 2004-04-21 devnull 
12 60d3db8e 2004-04-21 devnull 	if(randfd < 0){
13 3a6c348f 2005-09-19 devnull 		randfd = open(randfile="/dev/random", OREAD);
14 3a6c348f 2005-09-19 devnull 		/* OpenBSD lets you open /dev/random but not read it! */
15 3a6c348f 2005-09-19 devnull 		if(randfd < 0 || read(randfd, buf, 1) != 1)
16 3a6c348f 2005-09-19 devnull 			randfd = open(randfile="/dev/srandom", OREAD);	/* OpenBSD */
17 fea3228f 2005-08-11 devnull 		if(randfd < 0)
18 c4791fa5 2005-10-29 devnull 			sysfatal("can't open %s: %r", randfile);
19 60d3db8e 2004-04-21 devnull 		fcntl(randfd, F_SETFD, FD_CLOEXEC);
20 60d3db8e 2004-04-21 devnull 	}
21 60d3db8e 2004-04-21 devnull 	for(i=0; i<sizeof(buf); i += n)
22 60d3db8e 2004-04-21 devnull 		if((n = readn(randfd, buf+i, sizeof(buf)-i)) < 0)
23 3a6c348f 2005-09-19 devnull 			sysfatal("can't read %s: %r", randfile);
24 60d3db8e 2004-04-21 devnull 	return *((ulong*)buf);
25 60d3db8e 2004-04-21 devnull }