[NaCl SDK] nacl_io: Added support for access() syscall.

native_client_sdk/src/libraries/nacl_io/kernel_proxy.cc

 /* Copyright (c) 2012 The Chromium Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 #include "nacl_io/kernel_proxy.h"
 
 #include <assert.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <pthread.h>
@@ skipping 540 matching lines @@
   return result;
 }
 
 // TODO(noelallen): Needs implementation.
 int KernelProxy::fchmod(int fd, int mode) {
   errno = EINVAL;
   return -1;
 }
 
 int KernelProxy::access(const char* path, int amode) {
-  errno = EINVAL;
-  return -1;
+  Path rel;
+
+  Mount* mnt;
+  Error error = AcquireMountAndPath(path, &mnt, &rel);
+  if (error) {
+    errno = error;
+    return -1;
+  }
+
+  error = mnt->Access(rel, amode);
+  ReleaseMount(mnt);
+  if (error) {
+    errno = error;
+    return -1;
+  }
+  return 0;
 }
 
+// TODO(noelallen): Needs implementation.
 int KernelProxy::link(const char* oldpath, const char* newpath) {
   errno = EINVAL;
   return -1;
 }
 
 int KernelProxy::symlink(const char* oldpath, const char* newpath) {
   errno = EINVAL;
   return -1;
 }
 
@@ skipping 94 matching lines @@
   }
 
   int fd = AllocateFD(handle);
   mnt->AcquireNode(node);
 
   ReleaseHandle(handle);
   ReleaseMount(mnt);
 
   return fd;
 }