diff --git a/libc/Android.mk b/libc/Android.mk
index d044145..916b63c 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -290,6 +290,7 @@
     upstream-netbsd/lib/libc/stdlib/drand48.c \
     upstream-netbsd/lib/libc/stdlib/erand48.c \
     upstream-netbsd/lib/libc/stdlib/jrand48.c \
+    upstream-netbsd/lib/libc/stdlib/lcong48.c \
     upstream-netbsd/lib/libc/stdlib/ldiv.c \
     upstream-netbsd/lib/libc/stdlib/lldiv.c \
     upstream-netbsd/lib/libc/stdlib/lrand48.c \
diff --git a/libc/include/stdlib.h b/libc/include/stdlib.h
index b97eaf9..3053e85 100644
--- a/libc/include/stdlib.h
+++ b/libc/include/stdlib.h
@@ -103,15 +103,6 @@
 
 extern void qsort(void *, size_t, size_t, int (*)(const void *, const void *));
 
-extern long jrand48(unsigned short *);
-extern long mrand48(void);
-extern long nrand48(unsigned short *);
-extern long lrand48(void);
-extern unsigned short *seed48(unsigned short*);
-extern double erand48(unsigned short xsubi[3]);
-extern double drand48(void);
-extern void srand48(long);
-
 uint32_t arc4random(void);
 uint32_t arc4random_uniform(uint32_t);
 void arc4random_buf(void*, size_t);
@@ -122,6 +113,16 @@
 int rand_r(unsigned int*);
 void srand(unsigned int);
 
+double drand48(void);
+double erand48(unsigned short[3]);
+long jrand48(unsigned short[3]);
+void lcong48(unsigned short[7]);
+long lrand48(void);
+long mrand48(void);
+long nrand48(unsigned short[3]);
+unsigned short* seed48(unsigned short[3]);
+void srand48(long);
+
 char* initstate(unsigned int, char*, size_t);
 long random(void);
 char* setstate(char*);
diff --git a/libc/upstream-netbsd/lib/libc/stdlib/lcong48.c b/libc/upstream-netbsd/lib/libc/stdlib/lcong48.c
new file mode 100644
index 0000000..42ce979
--- /dev/null
+++ b/libc/upstream-netbsd/lib/libc/stdlib/lcong48.c
@@ -0,0 +1,43 @@
+/*	$NetBSD: lcong48.c,v 1.8 2005/06/12 05:21:28 lukem Exp $	*/
+
+/*
+ * Copyright (c) 1993 Martin Birgmeier
+ * All rights reserved.
+ *
+ * You may redistribute unmodified or modified versions of this source
+ * code provided that the above copyright notice and this and the
+ * following conditions are retained.
+ *
+ * This software is provided ``as is'', and comes with no warranties
+ * of any kind. I shall in no event be liable for anything that happens
+ * to anyone/anything when using this software.
+ */
+
+#include <sys/cdefs.h>
+#if defined(LIBC_SCCS) && !defined(lint)
+__RCSID("$NetBSD: lcong48.c,v 1.8 2005/06/12 05:21:28 lukem Exp $");
+#endif /* LIBC_SCCS and not lint */
+
+#include "namespace.h"
+
+#include <assert.h>
+
+#include "rand48.h"
+
+#ifdef __weak_alias
+__weak_alias(lcong48,_lcong48)
+#endif
+
+void
+lcong48(unsigned short p[7])
+{
+	_DIAGASSERT(p != NULL);
+
+	__rand48_seed[0] = p[0];
+	__rand48_seed[1] = p[1];
+	__rand48_seed[2] = p[2];
+	__rand48_mult[0] = p[3];
+	__rand48_mult[1] = p[4];
+	__rand48_mult[2] = p[5];
+	__rand48_add = p[6];
+}
diff --git a/tests/stdlib_test.cpp b/tests/stdlib_test.cpp
index 421cd82..050f5a7 100644
--- a/tests/stdlib_test.cpp
+++ b/tests/stdlib_test.cpp
@@ -28,12 +28,54 @@
 #include <sys/types.h>
 #include <sys/wait.h>
 
+// The random number generator tests all set the seed, get four values, reset the seed and check
+// that they get the first two values repeated, and then reset the seed and check two more values
+// to rule out the possibility that we're just going round a cycle of four values.
+// TODO: factor this out.
+
 TEST(stdlib, drand48) {
   srand48(0x01020304);
   EXPECT_DOUBLE_EQ(0.65619299195623526, drand48());
   EXPECT_DOUBLE_EQ(0.18522597229772941, drand48());
   EXPECT_DOUBLE_EQ(0.42015087072844537, drand48());
   EXPECT_DOUBLE_EQ(0.061637783047395089, drand48());
+  srand48(0x01020304);
+  EXPECT_DOUBLE_EQ(0.65619299195623526, drand48());
+  EXPECT_DOUBLE_EQ(0.18522597229772941, drand48());
+  srand48(0x01020304);
+  EXPECT_DOUBLE_EQ(0.65619299195623526, drand48());
+  EXPECT_DOUBLE_EQ(0.18522597229772941, drand48());
+}
+
+TEST(stdlib, erand48) {
+  const unsigned short seed[3] = { 0x330e, 0xabcd, 0x1234 };
+  unsigned short xsubi[3];
+  memcpy(xsubi, seed, sizeof(seed));
+  EXPECT_DOUBLE_EQ(0.39646477376027534, erand48(xsubi));
+  EXPECT_DOUBLE_EQ(0.84048536941142515, erand48(xsubi));
+  EXPECT_DOUBLE_EQ(0.35333609724524351, erand48(xsubi));
+  EXPECT_DOUBLE_EQ(0.44658343479654405, erand48(xsubi));
+  memcpy(xsubi, seed, sizeof(seed));
+  EXPECT_DOUBLE_EQ(0.39646477376027534, erand48(xsubi));
+  EXPECT_DOUBLE_EQ(0.84048536941142515, erand48(xsubi));
+  memcpy(xsubi, seed, sizeof(seed));
+  EXPECT_DOUBLE_EQ(0.39646477376027534, erand48(xsubi));
+  EXPECT_DOUBLE_EQ(0.84048536941142515, erand48(xsubi));
+}
+
+TEST(stdlib, lcong48) {
+  unsigned short p[7] = { 0x0102, 0x0304, 0x0506, 0x0708, 0x090a, 0x0b0c, 0x0d0e };
+  lcong48(p);
+  EXPECT_EQ(1531389981, lrand48());
+  EXPECT_EQ(1598801533, lrand48());
+  EXPECT_EQ(2080534853, lrand48());
+  EXPECT_EQ(1102488897, lrand48());
+  lcong48(p);
+  EXPECT_EQ(1531389981, lrand48());
+  EXPECT_EQ(1598801533, lrand48());
+  lcong48(p);
+  EXPECT_EQ(1531389981, lrand48());
+  EXPECT_EQ(1598801533, lrand48());
 }
 
 TEST(stdlib, lrand48) {
@@ -42,6 +84,12 @@
   EXPECT_EQ(397769746, lrand48());
   EXPECT_EQ(902267124, lrand48());
   EXPECT_EQ(132366131, lrand48());
+  srand48(0x01020304);
+  EXPECT_EQ(1409163720, lrand48());
+  EXPECT_EQ(397769746, lrand48());
+  srand48(0x01020304);
+  EXPECT_EQ(1409163720, lrand48());
+  EXPECT_EQ(397769746, lrand48());
 }
 
 TEST(stdlib, random) {
@@ -50,6 +98,12 @@
   EXPECT_EQ(1399865117, random());
   EXPECT_EQ(2032643283, random());
   EXPECT_EQ(571329216, random());
+  srandom(0x01020304);
+  EXPECT_EQ(55436735, random());
+  EXPECT_EQ(1399865117, random());
+  srandom(0x01020304);
+  EXPECT_EQ(55436735, random());
+  EXPECT_EQ(1399865117, random());
 }
 
 TEST(stdlib, rand) {
@@ -58,6 +112,12 @@
   EXPECT_EQ(1399865117, rand());
   EXPECT_EQ(2032643283, rand());
   EXPECT_EQ(571329216, rand());
+  srand(0x01020304);
+  EXPECT_EQ(55436735, rand());
+  EXPECT_EQ(1399865117, rand());
+  srand(0x01020304);
+  EXPECT_EQ(55436735, rand());
+  EXPECT_EQ(1399865117, rand());
 }
 
 TEST(stdlib, mrand48) {
@@ -66,6 +126,12 @@
   EXPECT_EQ(795539493, mrand48());
   EXPECT_EQ(1804534249, mrand48());
   EXPECT_EQ(264732262, mrand48());
+  srand48(0x01020304);
+  EXPECT_EQ(-1476639856, mrand48());
+  EXPECT_EQ(795539493, mrand48());
+  srand48(0x01020304);
+  EXPECT_EQ(-1476639856, mrand48());
+  EXPECT_EQ(795539493, mrand48());
 }
 
 TEST(stdlib, posix_memalign) {