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 0c9c620f 2010-03-10 rsc 	ulong x;
10 60d3db8e 2004-04-21 devnull 	static int randfd = -1;
11 3a6c348f 2005-09-19 devnull 	static char *randfile;
12 60d3db8e 2004-04-21 devnull 
13 60d3db8e 2004-04-21 devnull 	if(randfd < 0){
14 3a6c348f 2005-09-19 devnull 		randfd = open(randfile="/dev/random", OREAD);
15 3a6c348f 2005-09-19 devnull 		/* OpenBSD lets you open /dev/random but not read it! */
16 3a6c348f 2005-09-19 devnull 		if(randfd < 0 || read(randfd, buf, 1) != 1)
17 3a6c348f 2005-09-19 devnull 			randfd = open(randfile="/dev/srandom", OREAD);	/* OpenBSD */
18 fea3228f 2005-08-11 devnull 		if(randfd < 0)
19 c4791fa5 2005-10-29 devnull 			sysfatal("can't open %s: %r", randfile);
20 60d3db8e 2004-04-21 devnull 		fcntl(randfd, F_SETFD, FD_CLOEXEC);
21 60d3db8e 2004-04-21 devnull 	}
22 60d3db8e 2004-04-21 devnull 	for(i=0; i<sizeof(buf); i += n)
23 60d3db8e 2004-04-21 devnull 		if((n = readn(randfd, buf+i, sizeof(buf)-i)) < 0)
24 3a6c348f 2005-09-19 devnull 			sysfatal("can't read %s: %r", randfile);
25 0c9c620f 2010-03-10 rsc 	memmove(&x, buf, sizeof x);
26 0c9c620f 2010-03-10 rsc 	return x;
27 60d3db8e 2004-04-21 devnull }