diff --git a/libc/Android.bp b/libc/Android.bp
index 7b0ac23..b8ecf95 100644
--- a/libc/Android.bp
+++ b/libc/Android.bp
@@ -13,6 +13,7 @@
     "bionic/sigblock.c",
     "bionic/siginterrupt.c",
     "bionic/sigsetmask.c",
+    "stdio/fmemopen.cpp",
     "stdio/fread.c",
     "stdio/parsefloat.c",
     "stdio/refill.c",
@@ -438,7 +439,6 @@
         "upstream-openbsd/lib/libc/stdio/fgetwc.c",
         "upstream-openbsd/lib/libc/stdio/fgetws.c",
         "upstream-openbsd/lib/libc/stdio/flags.c",
-        "upstream-openbsd/lib/libc/stdio/fmemopen.c",
         "upstream-openbsd/lib/libc/stdio/fpurge.c",
         "upstream-openbsd/lib/libc/stdio/fputs.c",
         "upstream-openbsd/lib/libc/stdio/fputwc.c",
diff --git a/libc/NOTICE b/libc/NOTICE
index ae98d1d..90de7ef 100644
--- a/libc/NOTICE
+++ b/libc/NOTICE
@@ -682,6 +682,31 @@
 
 -------------------------------------------------------------------
 
+Copyright (C) 2013 Pietro Cerutti <gahr@FreeBSD.org>
+
+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.
+
+THIS SOFTWARE IS PROVIDED BY AUTHOR 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 AUTHOR 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.
+
+-------------------------------------------------------------------
+
 Copyright (C) 2013 The Android Open Source Project
 
 Licensed under the Apache License, Version 2.0 (the "License");
@@ -5071,23 +5096,6 @@
 
 -------------------------------------------------------------------
 
-Copyright (c) 2011 Martin Pieuchot <mpi@openbsd.org>
-Copyright (c) 2009 Ted Unangst
-
-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.
-
--------------------------------------------------------------------
-
 Copyright (c) 2011 The Android Open Source Project
 Copyright (c) 2008 ARM Ltd
 All rights reserved.
diff --git a/libc/stdio/fmemopen.cpp b/libc/stdio/fmemopen.cpp
new file mode 100644
index 0000000..9d8c41f
--- /dev/null
+++ b/libc/stdio/fmemopen.cpp
@@ -0,0 +1,156 @@
+/*-
+ * Copyright (C) 2013 Pietro Cerutti <gahr@FreeBSD.org>
+ *
+ * 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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY AUTHOR 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 AUTHOR 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 <sys/cdefs.h>
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "local.h"
+
+// See http://pubs.opengroup.org/onlinepubs/9699919799/functions/fmemopen.html
+// and http://man7.org/linux/man-pages/man3/fmemopen.3.html for documentation.
+
+struct fmemopen_cookie {
+  char* buf;
+  char* allocation;
+  size_t capacity;
+  size_t size;
+  size_t offset;
+  bool append;
+};
+
+static int fmemopen_read(void* cookie, char* buf, int n) {
+  fmemopen_cookie* ck = static_cast<fmemopen_cookie*>(cookie);
+
+  if (static_cast<size_t>(n) > ck->size - ck->offset) n = ck->size - ck->offset;
+
+  if (n > 0) {
+    memmove(buf, ck->buf + ck->offset, n);
+    ck->offset += n;
+  }
+  return n;
+}
+
+static int fmemopen_write(void* cookie, const char* buf, int n) {
+  fmemopen_cookie* ck = static_cast<fmemopen_cookie*>(cookie);
+
+  // We don't need to add the trailing NUL if there's already a trailing NUL
+  // in the data we're writing.
+  size_t space_for_null = (n > 0 && buf[n - 1] != '\0') ? 1 : 0;
+
+  // Undo any seeking/reading on an append-only stream.
+  if (ck->append) ck->offset = ck->size;
+
+  // How much can we actually fit?
+  if (static_cast<size_t>(n) + space_for_null > ck->capacity - ck->offset) {
+    n = ck->capacity - ck->offset - space_for_null;
+    // Give up if we don't even have room for one byte of userdata.
+    if (n <= 0) {
+      errno = ENOSPC;
+      return -1;
+    }
+  }
+
+  if (n > 0) {
+    memmove(ck->buf + ck->offset, buf, n);
+    ck->offset += n;
+    // Is this the furthest we've ever been?
+    if (ck->offset >= ck->size) {
+      if (buf[n - 1] != '\0') ck->buf[ck->offset] = '\0';
+      ck->size = ck->offset;
+    }
+  }
+  return n;
+}
+
+static fpos_t fmemopen_seek(void* cookie, fpos_t offset, int whence) {
+  fmemopen_cookie* ck = static_cast<fmemopen_cookie*>(cookie);
+
+  if (whence == SEEK_SET && (offset >= 0 && static_cast<size_t>(offset) <= ck->capacity)) {
+    return (ck->offset = offset);
+  } else if (whence == SEEK_CUR && (ck->offset + offset <= ck->capacity)) {
+    return (ck->offset += offset);
+  } else if (whence == SEEK_END && (offset <= 0 && static_cast<size_t>(-offset) <= ck->size)) {
+    return (ck->offset = ck->size + offset);
+  }
+  errno = EINVAL;
+  return -1;
+}
+
+static int fmemopen_close(void* cookie) {
+  fmemopen_cookie* ck = static_cast<fmemopen_cookie*>(cookie);
+  free(ck->allocation);
+  free(ck);
+  return 0;
+}
+
+FILE* fmemopen(void* buf, size_t capacity, const char* mode) {
+  int flags;
+  if (__sflags(mode, &flags) == 0) {
+    errno = EINVAL;
+    return nullptr;
+  }
+
+  fmemopen_cookie* ck = static_cast<fmemopen_cookie*>(calloc(sizeof(fmemopen_cookie), 1));
+  if (ck == nullptr) return nullptr;
+
+  ck->buf = static_cast<char*>(buf);
+  ck->capacity = capacity;
+
+  if (ck->buf == nullptr) ck->buf = ck->allocation = static_cast<char*>(calloc(capacity, 1));
+  if (ck->buf == nullptr) {
+    free(ck);
+    return nullptr;
+  }
+
+  FILE* fp = funopen(ck,
+                     (flags & O_WRONLY) ? nullptr : fmemopen_read,
+                     (flags & O_RDONLY) ? nullptr : fmemopen_write,
+                     fmemopen_seek,
+                     fmemopen_close);
+  if (fp == nullptr) {
+    fmemopen_close(ck);
+    return nullptr;
+  }
+
+  if (mode[0] == 'a') {
+    ck->size = strnlen(ck->buf, ck->capacity);
+    ck->offset = ck->size;
+    ck->append = true;
+  } else if (mode[0] == 'r') {
+    ck->size = capacity;
+    ck->offset = 0;
+  } else if (mode[0] == 'w') {
+    ck->size = 0;
+    ck->offset = 0;
+    ck->buf[0] = '\0';
+  }
+
+  return fp;
+}
diff --git a/libc/upstream-openbsd/lib/libc/stdio/fmemopen.c b/libc/upstream-openbsd/lib/libc/stdio/fmemopen.c
deleted file mode 100644
index 00c2764..0000000
--- a/libc/upstream-openbsd/lib/libc/stdio/fmemopen.c
+++ /dev/null
@@ -1,184 +0,0 @@
-/*	$OpenBSD: fmemopen.c,v 1.3 2015/08/31 02:53:57 guenther Exp $	*/
-
-/*
- * Copyright (c) 2011 Martin Pieuchot <mpi@openbsd.org>
- * Copyright (c) 2009 Ted Unangst
- *
- * 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 <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include "local.h"
-
-struct state {
-	char		*string;	/* actual stream */
-	size_t		 pos;		/* current position */
-	size_t		 size;		/* allocated size */
-	size_t		 len;		/* length of the data */
-	int		 update;	/* open for update */
-};
-
-static int
-fmemopen_read(void *v, char *b, int l)
-{
-	struct state	*st = v;
-	int		 i;
-
-	for (i = 0; i < l && i + st->pos < st->len; i++)
-		b[i] = st->string[st->pos + i];
-	st->pos += i;
-
-	return (i);
-}
-
-static int
-fmemopen_write(void *v, const char *b, int l)
-{
-	struct state	*st = v;
-	int		i;
-
-	for (i = 0; i < l && i + st->pos < st->size; i++)
-		st->string[st->pos + i] = b[i];
-	st->pos += i;
-
-	if (st->pos >= st->len) {
-		st->len = st->pos;
-
-		if (st->len < st->size)
-			st->string[st->len] = '\0';
-		else if (!st->update)
-			st->string[st->size - 1] = '\0';
-	}
-
-	return (i);
-}
-
-static fpos_t
-fmemopen_seek(void *v, fpos_t off, int whence)
-{
-	struct state	*st = v;
-	ssize_t		 base = 0;
-
-	switch (whence) {
-	case SEEK_SET:
-		break;
-	case SEEK_CUR:
-		base = st->pos;
-		break;
-	case SEEK_END:
-		base = st->len;
-		break;
-	}
-
-	if (off > st->size - base || off < -base) {
-		errno = EOVERFLOW;
-		return (-1);
-	}
-
-	st->pos = base + off;
-
-	return (st->pos);
-}
-
-static int
-fmemopen_close(void *v)
-{
-	free(v);
-
-	return (0);
-}
-
-static int
-fmemopen_close_free(void *v)
-{
-	struct state	*st = v;
-
-	free(st->string);
-	free(st);
-
-	return (0);
-}
-
-FILE *
-fmemopen(void *buf, size_t size, const char *mode)
-{
-	struct state	*st;
-	FILE		*fp;
-	int		 flags, oflags;
-
-	if (size == 0) {
-		errno = EINVAL;
-		return (NULL);
-	}
-
-	if ((flags = __sflags(mode, &oflags)) == 0) {
-		errno = EINVAL;
-		return (NULL);
-	}
-
-	if (buf == NULL && ((oflags & O_RDWR) == 0)) {
-		errno = EINVAL;
-		return (NULL);
-	}
-
-	if ((st = malloc(sizeof(*st))) == NULL)
-		return (NULL);
-
-	if ((fp = __sfp()) == NULL) {
-		free(st);
-		return (NULL);
-	}
-
-	st->pos = 0;
-	st->len = (oflags & O_WRONLY) ? 0 : size;
-	st->size = size;
-	st->update = oflags & O_RDWR;
-
-	if (buf == NULL) {
-		if ((st->string = malloc(size)) == NULL) {
-			free(st);
-			fp->_flags = 0;
-			return (NULL);
-		}
-		*st->string = '\0';
-	} else {
-		st->string = (char *)buf;
-
-		if (oflags & O_TRUNC)
-			*st->string = '\0';
-
-		if (oflags & O_APPEND) {
-			char	*p;
-
-			if ((p = memchr(st->string, '\0', size)) != NULL)
-				st->pos = st->len = (p - st->string);
-			else
-				st->pos = st->len = size;
-		}
-	}
-
-	fp->_flags = (short)flags;
-	fp->_file = -1;
-	fp->_cookie = (void *)st;
-	fp->_read = (flags & __SWR) ? NULL : fmemopen_read;
-	fp->_write = (flags & __SRD) ? NULL : fmemopen_write;
-	fp->_seek = fmemopen_seek;
-	fp->_close = (buf == NULL) ? fmemopen_close_free : fmemopen_close;
-
-	return (fp);
-}
-DEF_WEAK(fmemopen);