diff --git a/libc/bionic/tmpfile.cpp b/libc/bionic/tmpfile.cpp
new file mode 100644
index 0000000..ad58a92
--- /dev/null
+++ b/libc/bionic/tmpfile.cpp
@@ -0,0 +1,113 @@
+/*-
+ * Copyright (c) 1990, 1993
+ *	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 <errno.h>
+#include <signal.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+class ScopedSignalBlocker {
+ public:
+  ScopedSignalBlocker() {
+    sigset_t set;
+    sigfillset(&set);
+    sigprocmask(SIG_BLOCK, &set, &old_set_);
+  }
+
+  ~ScopedSignalBlocker() {
+    sigprocmask(SIG_SETMASK, &old_set_, NULL);
+  }
+
+ private:
+  sigset_t old_set_;
+};
+
+static FILE* __tmpfile_dir(const char* tmp_dir) {
+  char buf[PATH_MAX];
+  int path_length = snprintf(buf, sizeof(buf), "%s/tmp.XXXXXXXXXX", tmp_dir);
+  if (path_length >= sizeof(buf)) {
+    return NULL;
+  }
+
+  int fd;
+  {
+    ScopedSignalBlocker ssb;
+    fd = mkstemp(buf);
+    if (fd == -1) {
+      return NULL;
+    }
+
+    // Unlink the file now so that it's removed when closed.
+    unlink(buf);
+
+    // Can we still use the file now it's unlinked?
+    // File systems without hard link support won't have the usual Unix semantics.
+    struct stat sb;
+    int rc = fstat(fd, &sb);
+    if (rc == -1) {
+      int old_errno = errno;
+      close(fd);
+      errno = old_errno;
+      return NULL;
+    }
+  }
+
+  // Turn the file descriptor into a FILE*.
+  FILE* fp = fdopen(fd, "w+");
+  if (fp != NULL) {
+    return fp;
+  }
+
+  // Failure. Clean up. We already unlinked, so we just need to close.
+  int old_errno = errno;
+  close(fd);
+  errno = old_errno;
+  return NULL;
+}
+
+FILE* tmpfile() {
+  // TODO: get this app's temporary directory from the framework ("/data/data/app/cache").
+
+  // $EXTERNAL_STORAGE turns out not to be very useful because it doesn't support hard links.
+  // This means we can't do the usual trick of calling unlink before handing the file back.
+
+  FILE* fp = __tmpfile_dir("/data/local/tmp");
+  if (fp == NULL) {
+    // P_tmpdir is "/tmp/", but POSIX explicitly says that tmpdir(3) should try P_tmpdir before
+    // giving up. This is potentially useful for bionic on the host anyway.
+    fp = __tmpfile_dir(P_tmpdir);
+  }
+  return fp;
+}