X-Git-Url: http://nsz.repo.hu/git/?a=blobdiff_plain;f=src%2Fprng%2Frandom.c;h=d3780fa7eac3b47fd15ce51a546a66d1a0ce93a3;hb=ea3b40a321e751e016948087ef23ae7b9e8e0150;hp=4b2daef2116774776d8287c2191478442309efea;hpb=c7ce1b20d2f37f97f9cfcd57cb4fb4c7cd66a3a0;p=musl

diff --git a/src/prng/random.c b/src/prng/random.c
index 4b2daef2..d3780fa7 100644
--- a/src/prng/random.c
+++ b/src/prng/random.c
@@ -1,21 +1,12 @@
-/*
- * random.c - Copyright © 2011 Szabolcs Nagy
- * Permission to use, copy, modify, and/or distribute this code
- * for any purpose with or without fee is hereby granted.
- * There is no warranty.
-*/
-
 #include <stdlib.h>
 #include <stdint.h>
+#include "lock.h"
+#include "fork_impl.h"
 
 /*
 this code uses the same lagged fibonacci generator as the
 original bsd random implementation except for the seeding
-
-different seeds produce different sequences with long period
-(other libcs seed the state with a park-miller generator
-when seed=0 some fail to produce good random sequence
-others produce the same sequence as another seed)
+which was broken in the original
 */
 
 static uint32_t init[] = {
@@ -32,6 +23,8 @@ static int n = 31;
 static int i = 3;
 static int j = 0;
 static uint32_t *x = init+1;
+static volatile int lock[1];
+volatile int *const __random_lockptr = lock;
 
 static uint32_t lcg31(uint32_t x) {
 	return (1103515245*x + 12345) & 0x7fffffff;
@@ -53,7 +46,7 @@ static void loadstate(uint32_t *state) {
 	j = x[-1]&0xff;
 }
 
-void srandom(unsigned seed) {
+static void __srandom(unsigned seed) {
 	int k;
 	uint64_t s = seed;
 
@@ -71,11 +64,20 @@ void srandom(unsigned seed) {
 	x[0] |= 1;
 }
 
+void srandom(unsigned seed) {
+	LOCK(lock);
+	__srandom(seed);
+	UNLOCK(lock);
+}
+
 char *initstate(unsigned seed, char *state, size_t size) {
-	void *old = savestate();
+	void *old;
+
 	if (size < 8)
 		return 0;
-	else if (size < 32)
+	LOCK(lock);
+	old = savestate();
+	if (size < 32)
 		n = 0;
 	else if (size < 64)
 		n = 7;
@@ -86,26 +88,37 @@ char *initstate(unsigned seed, char *state, size_t size) {
 	else
 		n = 63;
 	x = (uint32_t*)state + 1;
-	srandom(seed);
+	__srandom(seed);
+	savestate();
+	UNLOCK(lock);
 	return old;
 }
 
 char *setstate(char *state) {
-	void *old = savestate();
+	void *old;
+
+	LOCK(lock);
+	old = savestate();
 	loadstate((uint32_t*)state);
+	UNLOCK(lock);
 	return old;
 }
 
 long random(void) {
 	long k;
 
-	if (n == 0)
-		return x[0] = lcg31(x[0]);
+	LOCK(lock);
+	if (n == 0) {
+		k = x[0] = lcg31(x[0]);
+		goto end;
+	}
 	x[i] += x[j];
 	k = x[i]>>1;
 	if (++i == n)
 		i = 0;
 	if (++j == n)
 		j = 0;
+end:
+	UNLOCK(lock);
 	return k;
 }