From: Karel Zak <kzak@redhat.com>
Date: Tue, 6 Sep 2016 08:19:52 +0000 (+0200)
Subject: lib/randutils: add xsrand() and rand_get_number()
X-Git-Tag: v2.29-rc1~78
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=a55d646bd3986937cd3a8488b6abaf74b2b9e28a;p=thirdparty%2Futil-linux.git

lib/randutils: add xsrand() and rand_get_number()

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/include/randutils.h b/include/randutils.h
index 17e2a02fac..7094a4c740 100644
--- a/include/randutils.h
+++ b/include/randutils.h
@@ -6,6 +6,11 @@
 #define rand()		random()
 #endif
 
+/* rand() based */
+extern void xsrand(void);
+extern int rand_get_number(int low_n, int high_n);
+
+/* /dev/urandom based with fallback to rand() */
 extern int random_get_fd(void);
 extern void random_get_bytes(void *buf, size_t nbytes);
 extern const char *random_tell_source(void);
diff --git a/lib/randutils.c b/lib/randutils.c
index 684ac0ac16..2e124bcb66 100644
--- a/lib/randutils.c
+++ b/lib/randutils.c
@@ -30,12 +30,24 @@
 THREAD_LOCAL unsigned short ul_jrand_seed[3];
 #endif
 
+void xsrand(void)
+{
+	struct timeval tv;
+
+	gettimeofday(&tv, 0);
+	srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
+}
+
+int rand_get_number(int low_n, int high_n)
+{
+	return rand() % (high_n - low_n + 1) + low_n;
+}
+
 int random_get_fd(void)
 {
 	int i, fd;
-	struct timeval	tv;
+	struct timeval tv;
 
-	gettimeofday(&tv, 0);
 	fd = open("/dev/urandom", O_RDONLY | O_CLOEXEC);
 	if (fd == -1)
 		fd = open("/dev/random", O_RDONLY | O_NONBLOCK | O_CLOEXEC);
@@ -44,7 +56,7 @@ int random_get_fd(void)
 		if (i >= 0)
 			fcntl(fd, F_SETFD, i | FD_CLOEXEC);
 	}
-	srand((getpid() << 16) ^ getuid() ^ tv.tv_sec ^ tv.tv_usec);
+	xsrand();
 
 #ifdef DO_JRAND_MIX
 	ul_jrand_seed[0] = getpid() ^ (tv.tv_sec & 0xFFFF);