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

native_client_sdk/src/libraries/nacl_io/mount_dev.cc

Index: native_client_sdk/src/libraries/nacl_io/mount_dev.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_dev.cc b/native_client_sdk/src/libraries/nacl_io/mount_dev.cc
index 11893ea09e8ff985c82bd569b12f5731b1132ac6..a7e507af5f3b7927e73e5dbcfa1c408478d78ae6 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_dev.cc
+++ b/native_client_sdk/src/libraries/nacl_io/mount_dev.cc
@@ -9,6 +9,7 @@
 #include <errno.h>
 #include <fcntl.h>
 #include <string.h>
+#include <unistd.h>
 #include "nacl_io/kernel_wrap_real.h"
 #include "nacl_io/mount_dev.h"
 #include "nacl_io/mount_node.h"
@@ -269,6 +270,22 @@ Error UrandomNode::Write(size_t offs,
 
 }  // namespace
 
+Error MountDev::Access(const Path& path, int a_mode) {
+  MountNode* node = NULL;
+
+  AutoLock lock(&lock_);
+
+  int error = root_->FindChild(path.Join(), &node);
+  if (error)
+    return error;
+
+  // Don't allow execute access.
+  if (a_mode & X_OK)
+    return EACCES;
+
+  return 0;
+}
+
 Error MountDev::Open(const Path& path, int mode, MountNode** out_node) {
   *out_node = NULL;