diff --git a/libc/arch-arm/arm.mk b/libc/arch-arm/arm.mk
index 60600e5..d72a160 100644
--- a/libc/arch-arm/arm.mk
+++ b/libc/arch-arm/arm.mk
@@ -5,8 +5,6 @@
 #
 
 libc_bionic_src_files_arm += \
-    bionic/memchr.c \
-    bionic/memrchr.c \
     bionic/strchr.cpp \
     bionic/strnlen.c \
     bionic/strrchr.cpp \
@@ -22,6 +20,8 @@
     upstream-freebsd/lib/libc/string/wmemmove.c \
 
 libc_openbsd_src_files_arm += \
+    upstream-openbsd/lib/libc/string/memchr.c \
+    upstream-openbsd/lib/libc/string/memrchr.c \
     upstream-openbsd/lib/libc/string/stpncpy.c \
     upstream-openbsd/lib/libc/string/strlcat.c \
     upstream-openbsd/lib/libc/string/strlcpy.c \
diff --git a/libc/arch-arm64/arm64.mk b/libc/arch-arm64/arm64.mk
index 8418993..470a038 100644
--- a/libc/arch-arm64/arm64.mk
+++ b/libc/arch-arm64/arm64.mk
@@ -8,7 +8,6 @@
     bionic/__memset_chk.cpp \
     bionic/__strcpy_chk.cpp \
     bionic/__strcat_chk.cpp \
-    bionic/memrchr.c \
     bionic/strrchr.cpp \
 
 libc_freebsd_src_files_arm64 += \
@@ -21,6 +20,7 @@
     upstream-freebsd/lib/libc/string/wmemcmp.c \
 
 libc_openbsd_src_files_arm64 += \
+    upstream-openbsd/lib/libc/string/memrchr.c \
     upstream-openbsd/lib/libc/string/stpncpy.c \
     upstream-openbsd/lib/libc/string/strcat.c \
     upstream-openbsd/lib/libc/string/strlcat.c \
diff --git a/libc/arch-mips/mips.mk b/libc/arch-mips/mips.mk
index 7e3fe25..33eceab 100644
--- a/libc/arch-mips/mips.mk
+++ b/libc/arch-mips/mips.mk
@@ -10,8 +10,6 @@
     bionic/__memset_chk.cpp \
     bionic/__strcpy_chk.cpp \
     bionic/__strcat_chk.cpp \
-    bionic/memchr.c \
-    bionic/memrchr.c \
     bionic/strchr.cpp \
     bionic/strnlen.c \
     bionic/strrchr.cpp \
@@ -27,7 +25,9 @@
     upstream-freebsd/lib/libc/string/wmemmove.c \
 
 libc_openbsd_src_files_mips += \
+    upstream-openbsd/lib/libc/string/memchr.c \
     upstream-openbsd/lib/libc/string/memmove.c \
+    upstream-openbsd/lib/libc/string/memrchr.c \
     upstream-openbsd/lib/libc/string/stpcpy.c \
     upstream-openbsd/lib/libc/string/stpncpy.c \
     upstream-openbsd/lib/libc/string/strcat.c \
diff --git a/libc/arch-mips64/mips64.mk b/libc/arch-mips64/mips64.mk
index 1376395..2b81e63 100644
--- a/libc/arch-mips64/mips64.mk
+++ b/libc/arch-mips64/mips64.mk
@@ -9,8 +9,6 @@
     bionic/__memset_chk.cpp \
     bionic/__strcpy_chk.cpp \
     bionic/__strcat_chk.cpp \
-    bionic/memchr.c \
-    bionic/memrchr.c \
     bionic/strchr.cpp \
     bionic/strnlen.c \
     bionic/strrchr.cpp \
@@ -30,7 +28,9 @@
     upstream-freebsd/lib/libc/string/wmemmove.c \
 
 libc_openbsd_src_files_mips64 += \
+    upstream-openbsd/lib/libc/string/memchr.c \
     upstream-openbsd/lib/libc/string/memmove.c \
+    upstream-openbsd/lib/libc/string/memrchr.c \
     upstream-openbsd/lib/libc/string/stpcpy.c \
     upstream-openbsd/lib/libc/string/stpncpy.c \
     upstream-openbsd/lib/libc/string/strcat.c \
diff --git a/libc/arch-x86_64/x86_64.mk b/libc/arch-x86_64/x86_64.mk
index ae01d2a..06d3185 100644
--- a/libc/arch-x86_64/x86_64.mk
+++ b/libc/arch-x86_64/x86_64.mk
@@ -9,8 +9,6 @@
     bionic/__memset_chk.cpp \
     bionic/__strcpy_chk.cpp \
     bionic/__strcat_chk.cpp \
-    bionic/memchr.c \
-    bionic/memrchr.c \
     bionic/strchr.cpp \
     bionic/strnlen.c \
     bionic/strrchr.cpp \
@@ -25,6 +23,10 @@
     upstream-freebsd/lib/libc/string/wmemcmp.c \
     upstream-freebsd/lib/libc/string/wmemmove.c \
 
+libc_openbsd_src_files_x86_64 += \
+    upstream-openbsd/lib/libc/string/memchr.c \
+    upstream-openbsd/lib/libc/string/memrchr.c \
+
 #
 # Inherently architecture-specific code.
 #
diff --git a/libc/bionic/memchr.c b/libc/bionic/memchr.c
deleted file mode 100644
index b14167a..0000000
--- a/libc/bionic/memchr.c
+++ /dev/null
@@ -1,46 +0,0 @@
-/*
- * Copyright (C) 2008 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-#include <stddef.h>
-#include <string.h>
-
-void *memchr(const void *s, int c, size_t n)
-{
-    const unsigned char*  p   = s;
-    const unsigned char*  end = p + n;
-
-    for (;;) {
-        if (p >= end || p[0] == c) break; p++;
-        if (p >= end || p[0] == c) break; p++;
-        if (p >= end || p[0] == c) break; p++;
-        if (p >= end || p[0] == c) break; p++;
-    }
-    if (p >= end)
-        return NULL;
-    else
-        return (void*) p;
-}
diff --git a/libc/bionic/memrchr.c b/libc/bionic/memrchr.c
deleted file mode 100644
index aeb5643..0000000
--- a/libc/bionic/memrchr.c
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * Copyright (C) 2008 The Android Open Source Project
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- *  * Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer.
- *  * Redistributions in binary form must reproduce the above copyright
- *    notice, this list of conditions and the following disclaimer in
- *    the documentation and/or other materials provided with the
- *    distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
- * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
- * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
- * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
- * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
- * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
- * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
- * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
- * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
- * SUCH DAMAGE.
- */
-#include <stddef.h>
-#include <string.h>
-
-void *memrchr(const void *s, int c, size_t n)
-{
-    if (n > 0) {
-        const char*  p = (const char*) s;
-        const char*  q = p + n;
-
-        while (1) {
-            q--; if (q < p || q[0] == (char) c) break;
-            q--; if (q < p || q[0] == (char) c) break;
-            q--; if (q < p || q[0] == (char) c) break;
-            q--; if (q < p || q[0] == (char) c) break;
-        }
-        if (q >= p)
-            return (void*)q;
-    }
-    return NULL;
-}
diff --git a/libc/upstream-openbsd/lib/libc/string/memchr.c b/libc/upstream-openbsd/lib/libc/string/memchr.c
new file mode 100644
index 0000000..4573e3c
--- /dev/null
+++ b/libc/upstream-openbsd/lib/libc/string/memchr.c
@@ -0,0 +1,48 @@
+/*	$OpenBSD: memchr.c,v 1.7 2005/08/08 08:05:37 espie Exp $ */
+/*-
+ * Copyright (c) 1990 The Regents of the University of California.
+ * All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Chris Torek.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. Neither the name of the University nor the names of its contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <string.h>
+
+void *
+memchr(const void *s, int c, size_t n)
+{
+	if (n != 0) {
+		const unsigned char *p = s;
+
+		do {
+			if (*p++ == (unsigned char)c)
+				return ((void *)(p - 1));
+		} while (--n != 0);
+	}
+	return (NULL);
+}
diff --git a/libc/upstream-openbsd/lib/libc/string/memrchr.c b/libc/upstream-openbsd/lib/libc/string/memrchr.c
new file mode 100644
index 0000000..bd27ebc
--- /dev/null
+++ b/libc/upstream-openbsd/lib/libc/string/memrchr.c
@@ -0,0 +1,38 @@
+/*	$OpenBSD: memrchr.c,v 1.2 2007/11/27 16:22:12 martynas Exp $	*/
+
+/*
+ * Copyright (c) 2007 Todd C. Miller <Todd.Miller@courtesan.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <string.h>
+
+/*
+ * Reverse memchr()
+ * Find the last occurrence of 'c' in the buffer 's' of size 'n'.
+ */
+void *
+memrchr(const void *s, int c, size_t n)
+{
+	const unsigned char *cp;
+
+	if (n != 0) {
+		cp = (unsigned char *)s + n;
+		do {
+			if (*(--cp) == (unsigned char)c)
+				return((void *)cp);
+		} while (--n != 0);
+	}
+	return(NULL);
+}
diff --git a/tests/string_test.cpp b/tests/string_test.cpp
index 137565e..66cf848 100644
--- a/tests/string_test.cpp
+++ b/tests/string_test.cpp
@@ -1385,3 +1385,13 @@
   TestBasename("///", "");
   TestBasename("//usr//lib//", "");
 }
+
+TEST(string, strnlen_147048) {
+  // https://code.google.com/p/android/issues/detail?id=147048
+  char stack_src[64] = {0};
+  EXPECT_EQ(0U, strnlen(stack_src, 1024*1024*1024));
+  char* heap_src = new char[1];
+  *heap_src = '\0';
+  EXPECT_EQ(0U, strnlen(heap_src, 1024*1024*1024));
+  delete[] heap_src;
+}