[NaCl SDK] nacl_io: Fix utime() on directories.

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 <limits.h>
@@ skipping 774 matching lines @@
 int KernelProxy::truncate(const char* path, off_t len) {
   ScopedFilesystem fs;
   ScopedNode node;
 
   Error error = AcquireFsAndNode(path, O_WRONLY, 0, &fs, &node);
   if (error) {
     errno = error;
     return -1;
   }
 
+  // Directories cannot be truncated.
+  if (node->IsaDir()) {
+    return EISDIR;
+  }
+
   if (!node->CanOpen(O_WRONLY)) {
     errno = EACCES;
     return -1;
   }
 
   error = node->FTruncate(len);
   if (error) {
     errno = error;
     return -1;
   }
@@ skipping 1007 matching lines @@
     errno = ENOTSOCK;
     return -1;
   }
 
   return 0;
 }
 
 #endif  // PROVIDES_SOCKET_API
 
 }  // namespace_nacl_io