From a4b2ac79e43381fa4f3b9be9e4f8ac1b8a0fac17 Mon Sep 17 00:00:00 2001
From: "Pedro F. Giffuni" <pfg@FreeBSD.org>
Date: Fri, 19 Sep 2014 18:24:02 +0000
Subject: [PATCH] awk: Use random(3) instead of rand(3)

While none of them is considered even near to cryptographic
level, random(3) is a better random generator than rand(3).

Use random(3) for awk as is done in other systems.

Thanks to Chenguang Li for discussing this in the lists
and submitting the patch upstream.

PR:		193147
MFC after:	5 weeks
---
 contrib/one-true-awk/awk.1  | 2 +-
 contrib/one-true-awk/main.c | 2 +-
 contrib/one-true-awk/run.c  | 8 +++++---
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/contrib/one-true-awk/awk.1 b/contrib/one-true-awk/awk.1
index 6119613c1aa..b0d243b495c 100644
--- a/contrib/one-true-awk/awk.1
+++ b/contrib/one-true-awk/awk.1
@@ -208,7 +208,7 @@ or of
 if no argument.
 .TP
 .B rand
-random number on (0,1)
+random number on [0,1)
 .TP
 .B srand
 sets seed for
diff --git a/contrib/one-true-awk/main.c b/contrib/one-true-awk/main.c
index ab01676f394..ec702945438 100644
--- a/contrib/one-true-awk/main.c
+++ b/contrib/one-true-awk/main.c
@@ -74,7 +74,7 @@ int main(int argc, char *argv[])
 	signal(SIGFPE, fpecatch);
 
 	srand_seed = 1;
-	srand(srand_seed);
+	srandom((unsigned long) srand_seed);
 
 	yyin = NULL;
 	symtab = makesymtab(NSYMTAB/NSYMTAB);
diff --git a/contrib/one-true-awk/run.c b/contrib/one-true-awk/run.c
index cafaff3e4ad..2bcd9dfa252 100644
--- a/contrib/one-true-awk/run.c
+++ b/contrib/one-true-awk/run.c
@@ -1521,8 +1521,10 @@ Cell *bltin(Node **a, int n)	/* builtin functions. a[0] is type, a[1] is arg lis
 		u = (Awkfloat) system(getsval(x)) / 256;   /* 256 is unix-dep */
 		break;
 	case FRAND:
-		/* in principle, rand() returns something in 0..RAND_MAX */
-		u = (Awkfloat) (rand() % RAND_MAX) / RAND_MAX;
+		/* random() returns numbers in [0..2^31-1]
+		 * in order to get a number in [0, 1), divide it by 2^31
+		 */
+		u = (Awkfloat) random() / (0x7fffffffL + 0x1UL);
 		break;
 	case FSRAND:
 		if (isrec(x))	/* no argument provided */
@@ -1530,7 +1532,7 @@ Cell *bltin(Node **a, int n)	/* builtin functions. a[0] is type, a[1] is arg lis
 		else
 			u = getfval(x);
 		tmp = u;
-		srand((unsigned int) u);
+		srandom((unsigned long) u);
 		u = srand_seed;
 		srand_seed = tmp;
 		break;