From 4535ac486ce87b6a7257a7959426138405b7ecf8 Mon Sep 17 00:00:00 2001
From: Philipp Klaus <philipp.klaus@gmail.com>
Date: Tue, 21 Jun 2011 17:12:21 +0200
Subject: automatic commit for pwgen-2.0

---
 randnum.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 92 insertions(+)
 create mode 100644 randnum.c

(limited to 'randnum.c')

diff --git a/randnum.c b/randnum.c
new file mode 100644
index 0000000..3f22cfe
--- /dev/null
+++ b/randnum.c
@@ -0,0 +1,92 @@
+/*
+ * randnum.c -- generate (good) randum numbers.
+ *
+ * Copyright (C) 2001 by Theodore Ts'o
+ * 
+ * This file may be distributed under the terms of the GNU Public
+ * License.
+ */
+
+#include <unistd.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <sys/time.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#include "pwgen.h"
+
+#ifdef HAVE_DRAND48
+extern double drand48();
+#endif
+
+/* Borrowed/adapted from e2fsprogs's UUID generation code */
+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);
+#ifdef HAVE_DRAND48
+		srand48((tv.tv_sec<<9) ^ (getpgrp()<<15) ^
+			(getpid()) ^ (tv.tv_usec>>11));
+#else
+		srandom((getpid() << 16) ^ (getpgrp() << 8) ^ getuid() 
+		      ^ tv.tv_sec ^ tv.tv_usec);
+#endif
+	}
+	/* Crank the random number generator a few times */
+	gettimeofday(&tv, 0);
+	for (i = (tv.tv_sec ^ tv.tv_usec) & 0x1F; i > 0; i--)
+#ifdef HAVE_DRAND48
+		drand48();
+#else
+		rand();
+#endif
+	return fd;
+}
+
+/*
+ * Generate a random number n, where 0 <= n < max_num, using
+ * /dev/urandom if possible.
+ */
+int pw_random_number(int max_num)
+{
+	int i, fd = get_random_fd();
+	int lose_counter = 0, nbytes=4;
+	unsigned int rand;
+	char *cp = (char *) &rand;
+
+	if (fd >= 0) {
+		while (nbytes > 0) {
+			i = read(fd, cp, nbytes);
+			if ((i < 0) &&
+			    ((errno == EINTR) || (errno == EAGAIN)))
+				continue;
+			if (i <= 0) {
+				if (lose_counter++ == 8)
+					break;
+				continue;
+			}
+			nbytes -= i;
+			cp += i;
+			lose_counter = 0;
+		}
+	}
+	if (nbytes == 0)
+		return (rand % max_num);
+
+	/* OK, we weren't able to use /dev/random, fall back to rand/rand48 */
+
+#ifdef RAND48
+	return ((int) ((drand48() * max_num)));
+#else
+	return ((int) (random() / ((float) RAND_MAX) * max_num));
+#endif
+}
-- 
cgit v1.2.3