diff --git a/libc/Android.mk b/libc/Android.mk
index 6a77deb..45dadd2 100644
--- a/libc/Android.mk
+++ b/libc/Android.mk
@@ -123,7 +123,6 @@
 	stdio/sscanf.c \
 	stdio/stdio.c \
 	stdio/tempnam.c \
-	stdio/tmpfile.c \
 	stdio/tmpnam.c \
 	stdio/ungetc.c \
 	stdio/vasprintf.c \
@@ -257,6 +256,7 @@
 	tzcode/strftime.c \
 	tzcode/strptime.c \
 	bionic/__set_errno.c \
+	bionic/__umask_chk.c \
 	bionic/bionic_clone.c \
 	bionic/cpuacct.c \
 	bionic/arc4random.c \
@@ -296,6 +296,7 @@
 	bionic/tdestroy.c \
 	bionic/time64.c \
 	bionic/thread_atexit.c \
+	bionic/tmpfile.cpp \
 	bionic/utime.c \
 	bionic/utmp.c \
 	netbsd/gethnamaddr.c \
diff --git a/libc/bionic/__umask_chk.c b/libc/bionic/__umask_chk.c
new file mode 100644
index 0000000..5bb6a3b
--- /dev/null
+++ b/libc/bionic/__umask_chk.c
@@ -0,0 +1,53 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#undef _FORTIFY_SOURCE
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <private/logd.h>
+#include <stdlib.h>
+
+/*
+ * Runtime implementation of __umask_chk.
+ *
+ * Validate that umask is called with sane mode.
+ *
+ * This umask check is called if _FORTIFY_SOURCE is defined and
+ * greater than 0.
+ */
+mode_t __umask_chk(mode_t mode)
+{
+    if ((mode & 0777) != mode) {
+        __libc_android_log_print(ANDROID_LOG_FATAL, "libc",
+            "*** FORTIFY_SOURCE: umask called with invalid mask ***\n");
+        abort();
+    }
+
+    return umask(mode);
+}
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;
+}
diff --git a/libc/include/sys/stat.h b/libc/include/sys/stat.h
index bee648e..62e0d8b 100644
--- a/libc/include/sys/stat.h
+++ b/libc/include/sys/stat.h
@@ -122,6 +122,27 @@
 extern int    mknod(const char *, mode_t, dev_t);
 extern mode_t umask(mode_t);
 
+#if defined(__BIONIC_FORTIFY_INLINE)
+
+extern mode_t __umask_chk(mode_t);
+extern mode_t __umask_real(mode_t)
+    __asm__(__USER_LABEL_PREFIX__ "umask");
+extern void __umask_error()
+    __attribute__((__error__("umask called with invalid mode")));
+
+__BIONIC_FORTIFY_INLINE
+mode_t umask(mode_t mode) {
+  if (__builtin_constant_p(mode)) {
+    if ((mode & 0777) != mode) {
+      __umask_error();
+    }
+    return __umask_real(mode);
+  }
+  return __umask_chk(mode);
+}
+#endif /* defined(__BIONIC_FORTIFY_INLINE) */
+
+
 #define  stat64    stat
 #define  fstat64   fstat
 #define  lstat64   lstat
diff --git a/libc/stdio/tmpfile.c b/libc/stdio/tmpfile.c
deleted file mode 100644
index 39f7e92..0000000
--- a/libc/stdio/tmpfile.c
+++ /dev/null
@@ -1,81 +0,0 @@
-/*	$OpenBSD: tmpfile.c,v 1.10 2005/10/10 12:00:52 espie Exp $ */
-/*-
- * 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 <sys/types.h>
-#include <sys/stat.h>
-#include <unistd.h>
-#include <signal.h>
-#include <errno.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <paths.h>
-
-FILE *
-tmpfile(void)
-{
-	sigset_t set, oset;
-	FILE *fp;
-	int fd, sverrno;
-#define	TRAILER	"tmp.XXXXXXXXXX"
-	char buf[sizeof(_PATH_TMP) + sizeof(TRAILER)];
-
-	(void)memcpy(buf, _PATH_TMP, sizeof(_PATH_TMP) - 1);
-	(void)memcpy(buf + sizeof(_PATH_TMP) - 1, TRAILER, sizeof(TRAILER));
-
-	sigfillset(&set);
-	(void)sigprocmask(SIG_BLOCK, &set, &oset);
-
-	fd = mkstemp(buf);
-	if (fd != -1) {
-		mode_t u;
-
-		(void)unlink(buf);
-		u = umask(0);
-		(void)umask(u);
-		(void)fchmod(fd, 0666 & ~u);
-	}
-
-	(void)sigprocmask(SIG_SETMASK, &oset, NULL);
-
-	if (fd == -1)
-		return (NULL);
-
-	if ((fp = fdopen(fd, "w+")) == NULL) {
-		sverrno = errno;
-		(void)close(fd);
-		errno = sverrno;
-		return (NULL);
-	}
-	return (fp);
-}
diff --git a/linker/dlfcn.c b/linker/dlfcn.c
index 44ab158..920137e 100644
--- a/linker/dlfcn.c
+++ b/linker/dlfcn.c
@@ -138,7 +138,8 @@
         memset(info, 0, sizeof(Dl_info));
 
         info->dli_fname = si->name;
-        info->dli_fbase = (void*)si->load_bias;
+        /* Address at which the shared object is loaded */
+        info->dli_fbase = (void*)si->base;
 
         /* Determine if any symbol in the library contains the specified address */
         Elf32_Sym *sym = soinfo_find_symbol(si, addr);
diff --git a/tests/Android.mk b/tests/Android.mk
index be47585..38f8ceb 100644
--- a/tests/Android.mk
+++ b/tests/Android.mk
@@ -22,6 +22,7 @@
     getcwd_test.cpp \
     pthread_test.cpp \
     regex_test.cpp \
+    stdio_test.cpp \
     string_test.cpp \
     stubs_test.cpp \
 
diff --git a/tests/dlopen_test.cpp b/tests/dlopen_test.cpp
index c290b4d..c41c5e6 100644
--- a/tests/dlopen_test.cpp
+++ b/tests/dlopen_test.cpp
@@ -17,6 +17,12 @@
 #include <gtest/gtest.h>
 
 #include <dlfcn.h>
+#include <libgen.h>
+#include <limits.h>
+#include <stdio.h>
+#include <stdint.h>
+
+#include <string>
 
 static bool gCalled = false;
 extern "C" void DlSymTestFunction() {
@@ -36,3 +42,69 @@
   function();
   ASSERT_TRUE(gCalled);
 }
+
+TEST(dlopen, dladdr) {
+  void* self = dlopen(NULL, RTLD_NOW);
+  ASSERT_TRUE(self != NULL);
+
+  void* sym = dlsym(self, "DlSymTestFunction");
+  ASSERT_TRUE(sym != NULL);
+
+  // Deliberately ask dladdr for an address inside a symbol, rather than the symbol base address.
+  void* addr = reinterpret_cast<void*>(reinterpret_cast<uintptr_t>(sym) + 2);
+
+  Dl_info info;
+  int rc = dladdr(addr, &info);
+  ASSERT_NE(rc, 0); // Zero on error, non-zero on success.
+
+  // Get the name of this executable.
+  char executable_path[PATH_MAX];
+  rc = readlink("/proc/self/exe", executable_path, sizeof(executable_path));
+  ASSERT_NE(rc, -1);
+  executable_path[rc] = '\0';
+  std::string executable_name(basename(executable_path));
+
+  // The filename should be that of this executable.
+  // Note that we don't know whether or not we have the full path, so we want an "ends_with" test.
+  std::string dli_fname(info.dli_fname);
+  dli_fname = basename(&dli_fname[0]);
+  ASSERT_EQ(dli_fname, executable_name);
+
+  // The symbol name should be the symbol we looked up.
+  ASSERT_STREQ(info.dli_sname, "DlSymTestFunction");
+
+  // The address should be the exact address of the symbol.
+  ASSERT_EQ(info.dli_saddr, sym);
+
+  // Look in /proc/pid/maps to find out what address we were loaded at.
+  // TODO: factor /proc/pid/maps parsing out into a class and reuse all over bionic.
+  void* base_address = NULL;
+  char path[PATH_MAX];
+  snprintf(path, sizeof(path), "/proc/%d/maps", getpid());
+  char line[BUFSIZ];
+  FILE* fp = fopen(path, "r");
+  ASSERT_TRUE(fp != NULL);
+  while (fgets(line, sizeof(line), fp) != NULL) {
+    uintptr_t start = strtoul(line, 0, 16);
+    line[strlen(line) - 1] = '\0'; // Chomp the '\n'.
+    char* path = strchr(line, '/');
+    if (strcmp(executable_path, path) == 0) {
+      base_address = reinterpret_cast<void*>(start);
+      break;
+    }
+  }
+  fclose(fp);
+
+  // The base address should be the address we were loaded at.
+  ASSERT_EQ(info.dli_fbase, base_address);
+}
+
+TEST(dlopen, dladdr_invalid) {
+  Dl_info info;
+
+  // No symbol corresponding to NULL.
+  ASSERT_EQ(dladdr(NULL, &info), 0); // Zero on error, non-zero on success.
+
+  // No symbol corresponding to a stack address.
+  ASSERT_EQ(dladdr(&info, &info), 0); // Zero on error, non-zero on success.
+}
diff --git a/tests/stdio_test.cpp b/tests/stdio_test.cpp
new file mode 100644
index 0000000..72af796
--- /dev/null
+++ b/tests/stdio_test.cpp
@@ -0,0 +1,48 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <gtest/gtest.h>
+
+#include <errno.h>
+#include <stdio.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+TEST(stdio, tmpfile_fileno_fprintf_rewind_fgets) {
+  FILE* fp = tmpfile();
+  ASSERT_TRUE(fp != NULL);
+
+  int fd = fileno(fp);
+  ASSERT_NE(fd, -1);
+
+  struct stat sb;
+  int rc = fstat(fd, &sb);
+  ASSERT_NE(rc, -1);
+  ASSERT_EQ(sb.st_mode & 0777, 0600U);
+
+  rc = fprintf(fp, "hello\n");
+  ASSERT_EQ(rc, 6);
+
+  rewind(fp);
+
+  char buf[16];
+  char* s = fgets(buf, sizeof(buf), fp);
+  ASSERT_TRUE(s != NULL);
+  ASSERT_STREQ("hello\n", s);
+
+  fclose(fp);
+}