Libc-498.tar.gz

[apple/libc.git] / uuid / uuidsrc / gen_uuid.c.patch

--- gen_uuid.c.orig	2006-02-19 03:05:40.000000000 -0800
+++ gen_uuid.c	2006-02-20 12:51:07.000000000 -0800
@@ -72,62 +72,24 @@
 
 #include "uuidP.h"
 
-#ifdef HAVE_SRANDOM
-#define srand(x) 	srandom(x)
-#define rand() 		random()
-#endif
-
-static int get_random_fd(void)
-{
-	struct timeval	tv;
-	static int	fd = -2;
-	int		i;
-
-	if (fd == -2) {
-		gettimeofday(&tv, 0);
-		fd = open("/dev/urandom", O_RDONLY);
-		if (fd == -1)
-			fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
-		srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
-	}
-	/* Crank the random number generator a few times */
-	gettimeofday(&tv, 0);
-	for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
-		rand();
-	return fd;
-}
-
-
 /*
- * Generate a series of random bytes.  Use /dev/urandom if possible,
- * and if not, use srandom/random.
+ * Generate a series of random bytes, using arc4random
  */
 static void get_random_bytes(void *buf, int nbytes)
 {
-	int i, n = nbytes, fd = get_random_fd();
-	int lose_counter = 0;
 	unsigned char *cp = (unsigned char *) buf;
+	u_int32_t u;
+	int n = nbytes / sizeof(u);
 
-	if (fd >= 0) {
-		while (n > 0) {
-			i = read(fd, cp, n);
-			if (i <= 0) {
-				if (lose_counter++ > 16)
-					break;
-				continue;
-			}
-			n -= i;
-			cp += i;
-			lose_counter = 0;
-		}
+	while (n-- > 0) {
+		u = arc4random();
+		memcpy(cp, &u, sizeof(u));
+		cp += sizeof(u);
+	}
+	if ((n = nbytes % sizeof(u)) > 0) {
+		u = arc4random();
+		memcpy(cp, &u, n);
 	}
-	
-	/*
-	 * We do this all the time, but this is the only source of
-	 * randomness if /dev/random/urandom is out to lunch.
-	 */
-	for (cp = buf, i = 0; i < nbytes; i++)
-		*cp++ ^= (rand() >> 7) & 0xFF;
 	return;
 }
 
@@ -302,15 +264,9 @@
 }
 
 /*
- * This is the generic front-end to uuid_generate_random and
- * uuid_generate_time.  It uses uuid_generate_random only if
- * /dev/urandom is available, since otherwise we won't have
- * high-quality randomness.
+ * This is the generic front-end
  */
 void uuid_generate(uuid_t out)
 {
-	if (get_random_fd() >= 0)
-		uuid_generate_random(out);
-	else
-		uuid_generate_time(out);
+	uuid_generate_random(out);
 }