diff --git a/libc/bionic/opendir.c b/libc/bionic/opendir.c
deleted file mode 100644
index f178bc6..0000000
--- a/libc/bionic/opendir.c
+++ /dev/null
@@ -1,273 +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 <unistd.h>
-#include <dirent.h>
-#include <memory.h>
-#include <string.h>
-#include <fcntl.h>
-#include <stdlib.h>
-#include <pthread.h>
-#include <errno.h>
-
-struct DIR
-{
-    int              _DIR_fd;
-    size_t           _DIR_avail;
-    struct dirent*   _DIR_next;
-    pthread_mutex_t  _DIR_lock;
-    struct dirent    _DIR_buff[15];
-};
-
-int dirfd(DIR* dirp)
-{
-    return dirp->_DIR_fd;
-}
-
-DIR*  opendir( const char*  dirpath )
-{
-    DIR*  dir = malloc(sizeof(DIR));
-
-    if (!dir)
-        goto Exit;
-
-    dir->_DIR_fd = open(dirpath, O_RDONLY|O_DIRECTORY);
-    if (dir->_DIR_fd < 0)
-    {
-        free(dir);
-        dir = NULL;
-    }
-    else
-    {
-        dir->_DIR_avail = 0;
-        dir->_DIR_next  = NULL;
-        pthread_mutex_init( &dir->_DIR_lock, NULL );
-    }
-Exit:
-    return dir;
-}
-
-
-DIR*  fdopendir(int fd)
-{
-    DIR*  dir = malloc(sizeof(DIR));
-
-    if (!dir)
-        return 0;
-
-    dir->_DIR_fd = fd;
-    dir->_DIR_avail = 0;
-    dir->_DIR_next  = NULL;
-    pthread_mutex_init( &dir->_DIR_lock, NULL );
-
-    return dir;
-}
-
-
-static struct dirent*
-_readdir_unlocked(DIR*  dir)
-{
-    struct dirent*  entry;
-#ifndef NDEBUG
-    unsigned reclen;
-#endif
-
-    if ( !dir->_DIR_avail )
-    {
-        int  rc;
-
-        for (;;) {
-            rc = getdents( dir->_DIR_fd, dir->_DIR_buff, sizeof(dir->_DIR_buff));
-            if (rc >= 0 || errno != EINTR)
-            break;
-        }
-        if (rc <= 0)
-            return NULL;
-
-        dir->_DIR_avail = rc;
-        dir->_DIR_next  = dir->_DIR_buff;
-    }
-
-    entry = dir->_DIR_next;
-
-    /* perform some sanity checks here */
-    if (((long)(void*)entry & 3) != 0)
-        return NULL;
-
-#ifndef NDEBUG
-    // paranoid testing of the interface with the kernel getdents64 system call
-    reclen = offsetof(struct dirent, d_name) + strlen(entry->d_name) + 1;
-    if ( reclen > sizeof(*entry) || reclen <= offsetof(struct dirent, d_name) )
-        goto Bad;
-
-    if ( (char*)entry + reclen > (char*)dir->_DIR_buff + sizeof(dir->_DIR_buff) )
-        goto Bad;
-
-    if ( !memchr( entry->d_name, 0, reclen - offsetof(struct dirent, d_name)) )
-        goto Bad; 
-#endif
-
-    dir->_DIR_next   = (struct dirent*)((char*)entry + entry->d_reclen);
-    dir->_DIR_avail -= entry->d_reclen;
-
-    return entry;
-
-  Bad:
-    errno = EINVAL;
-    return NULL;
-}
-
-
-struct dirent*
-readdir(DIR * dir)
-{
-    struct dirent *entry = NULL;
-
-    pthread_mutex_lock( &dir->_DIR_lock );
-    entry = _readdir_unlocked(dir);
-    pthread_mutex_unlock( &dir->_DIR_lock );
-
-    return entry;
-}
-
-
-int readdir_r(DIR*  dir, struct dirent *entry, struct dirent **result)
-{
-    struct dirent*  ent;
-    int  save_errno = errno;
-    int  retval;
-
-    *result = NULL;
-    errno   = 0;
-
-    pthread_mutex_lock( &dir->_DIR_lock );
-
-    ent    = _readdir_unlocked(dir);
-    retval = errno;
-    if (ent == NULL) {
-        if (!retval) {
-            errno = save_errno;
-        }
-    } else {
-        if (!retval) {
-            errno   = save_errno;
-            *result = entry;
-            memcpy( entry, ent, ent->d_reclen );
-        }
-    }
-
-    pthread_mutex_unlock( &dir->_DIR_lock );
-
-    return retval;
-}
-
-
-
-int closedir(DIR *dir)
-{
-  int rc;
-
-  rc = close(dir->_DIR_fd);
-  dir->_DIR_fd = -1;
-
-  pthread_mutex_destroy( &dir->_DIR_lock );
-
-  free(dir);
-  return rc;
-}
-
-
-void   rewinddir(DIR *dir)
-{
-    pthread_mutex_lock( &dir->_DIR_lock );
-    lseek( dir->_DIR_fd, 0, SEEK_SET );
-    dir->_DIR_avail = 0;
-    pthread_mutex_unlock( &dir->_DIR_lock );
-}
-
-
-int alphasort(const void *a, const void *b)
-{
-        struct dirent **d1, **d2;
-
-        d1 = (struct dirent **) a;
-        d2 = (struct dirent **) b;
-        return strcmp((*d1)->d_name, (*d2)->d_name);
-}
-
-
-int scandir(const char *dir, struct dirent ***namelist,
-            int(*filter)(const struct dirent *),
-            int(*compar)(const struct dirent **, const struct dirent **))
-{
-    DIR *d;
-    int n_elem = 0;
-    struct dirent *this_de, *de;
-    struct dirent **de_list = NULL;
-    int de_list_size = 0;
-
-    d = opendir(dir);
-    if (d == NULL) {
-        return -1;
-    }
-
-    while ((this_de = readdir(d)) != NULL) {
-        if (filter && (*filter)(this_de) == 0) {
-            continue;
-        }
-        if (n_elem == 0) {
-            de_list_size = 4;
-            de_list = (struct dirent **) 
-                    malloc(sizeof(struct dirent *)*de_list_size);
-            if (de_list == NULL) {
-                return -1;
-            }
-        }
-        else if (n_elem == de_list_size) {
-            struct dirent **de_list_new;
-
-            de_list_size += 10;
-            de_list_new = (struct dirent **) 
-                    realloc(de_list, sizeof(struct dirent *)*de_list_size);
-            if (de_list_new == NULL) {
-                free(de_list);
-                return -1;
-            }
-            de_list = de_list_new;
-        }
-        de = (struct dirent *) malloc(sizeof(struct dirent));
-        *de = *this_de;
-        de_list[n_elem++] = de;
-    }
-    closedir(d);
-    if (n_elem && compar) {
-        qsort(de_list, n_elem, sizeof(struct dirent *), 
-              (int (*)(const void *, const void *)) compar);
-    }
-    *namelist = de_list;
-    return n_elem;
-}
diff --git a/libc/bionic/opendir.cpp b/libc/bionic/opendir.cpp
new file mode 100644
index 0000000..cd5b221
--- /dev/null
+++ b/libc/bionic/opendir.cpp
@@ -0,0 +1,192 @@
+/*
+ * 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 <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <private/ScopedPthreadMutexLocker.h>
+
+struct DIR {
+  int fd_;
+  size_t available_bytes_;
+  dirent* next_;
+  pthread_mutex_t mutex_;
+  dirent buff_[15];
+};
+
+static DIR* __allocate_DIR(int fd) {
+  DIR* d = reinterpret_cast<DIR*>(malloc(sizeof(DIR)));
+  if (d == NULL) {
+    return NULL;
+  }
+  d->fd_ = fd;
+  d->available_bytes_ = 0;
+  d->next_ = NULL;
+  pthread_mutex_init(&d->mutex_, NULL);
+  return d;
+}
+
+int dirfd(DIR* dirp) {
+  return dirp->fd_;
+}
+
+DIR* fdopendir(int fd) {
+  // Is 'fd' actually a directory?
+  struct stat sb;
+  if (fstat(fd, &sb) == -1) {
+    return NULL;
+  }
+  if (!S_ISDIR(sb.st_mode)) {
+    errno = ENOTDIR;
+    return NULL;
+  }
+
+  return __allocate_DIR(fd);
+}
+
+DIR* opendir(const char* path) {
+  int fd = open(path, O_RDONLY | O_DIRECTORY);
+  return (fd != -1) ? __allocate_DIR(fd) : NULL;
+}
+
+static bool __fill_DIR(DIR* d) {
+  int rc = TEMP_FAILURE_RETRY(getdents(d->fd_, d->buff_, sizeof(d->buff_)));
+  if (rc <= 0) {
+    return false;
+  }
+  d->available_bytes_ = rc;
+  d->next_ = d->buff_;
+  return true;
+}
+
+static dirent* __readdir_locked(DIR* d) {
+  if (d->available_bytes_ == 0 && !__fill_DIR(d)) {
+    return NULL;
+  }
+
+  dirent* entry = d->next_;
+  d->next_ = reinterpret_cast<dirent*>(reinterpret_cast<char*>(entry) + entry->d_reclen);
+  d->available_bytes_ -= entry->d_reclen;
+  return entry;
+}
+
+dirent* readdir(DIR* d) {
+  ScopedPthreadMutexLocker locker(&d->mutex_);
+  return __readdir_locked(d);
+}
+
+int readdir_r(DIR* d, dirent* entry, dirent** result) {
+  int saved_errno = errno;
+
+  *result = NULL;
+  errno = 0;
+
+  ScopedPthreadMutexLocker locker(&d->mutex_);
+
+  dirent* next = __readdir_locked(d);
+  if (errno != 0 && next == NULL) {
+    return errno;
+  }
+
+  if (next != NULL) {
+    memcpy(entry, next, next->d_reclen);
+    *result = entry;
+  }
+  errno = saved_errno;
+  return 0;
+}
+
+int closedir(DIR* d) {
+  if (d == NULL) {
+    errno = EINVAL;
+    return -1;
+  }
+
+  int fd = d->fd_;
+  pthread_mutex_destroy(&d->mutex_);
+  free(d);
+  return close(fd);
+}
+
+void rewinddir(DIR* d) {
+  ScopedPthreadMutexLocker locker(&d->mutex_);
+  lseek(d->fd_, 0, SEEK_SET);
+  d->available_bytes_ = 0;
+}
+
+int scandir(const char* path, dirent*** namelist,
+            int(*filter)(const dirent*),
+            int(*compar)(const dirent**, const dirent**))
+{
+  int n_elem = 0;
+  dirent* this_de, *de;
+  dirent** de_list = NULL;
+  int de_list_size = 0;
+
+  DIR* d = opendir(path);
+  if (d == NULL) {
+    return -1;
+  }
+
+  while ((this_de = readdir(d)) != NULL) {
+    if (filter != NULL && (*filter)(this_de) == 0) {
+      continue;
+    }
+    if (n_elem == 0) {
+      de_list_size = 4;
+      de_list = (dirent**) malloc(sizeof(dirent*) * de_list_size);
+      if (de_list == NULL) {
+        return -1;
+      }
+    } else if (n_elem == de_list_size) {
+      de_list_size += 10;
+      dirent** de_list_new = (dirent**) realloc(de_list, sizeof(dirent*) * de_list_size);
+      if (de_list_new == NULL) {
+        free(de_list);
+        return -1;
+      }
+      de_list = de_list_new;
+    }
+    de = (dirent*) malloc(sizeof(dirent));
+    *de = *this_de;
+    de_list[n_elem++] = de;
+  }
+  closedir(d);
+  if (n_elem && compar) {
+    qsort(de_list, n_elem, sizeof(dirent*), (int (*)(const void*, const void*)) compar);
+  }
+  *namelist = de_list;
+  return n_elem;
+}
diff --git a/libc/bionic/sysconf.c b/libc/bionic/sysconf.c
index 7caa4e9..d21a703 100644
--- a/libc/bionic/sysconf.c
+++ b/libc/bionic/sysconf.c
@@ -85,9 +85,8 @@
   }
 
   int result = 0;
-  struct dirent de;
   struct dirent* e;
-  while (!readdir_r(d, &de, &e) && e != NULL) {
+  while ((e = readdir(d)) != NULL) {
     if (e->d_type == DT_DIR && __matches_cpuN(e->d_name)) {
       ++result;
     }