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

native_client_sdk/src/libraries/nacl_io/mount_mem.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/mount_mem.h"
 
 #include <errno.h>
 #include <fcntl.h>
 #include <string>
+#include <unistd.h>
 
 #include "nacl_io/mount.h"
 #include "nacl_io/mount_node.h"
 #include "nacl_io/mount_node_dir.h"
 #include "nacl_io/mount_node_mem.h"
 #include "nacl_io/osstat.h"
 #include "nacl_io/path.h"
 #include "sdk_util/auto_lock.h"
 #include "sdk_util/ref_object.h"
 
@@ skipping 49 matching lines @@
 
   // If a file is expected, but it's not a file, then fail.
   if ((type & S_IFREG) && node->IsaDir())
     return EISDIR;
 
   // We now have a valid object of the expected type, so return it.
   *out_node = node;
   return 0;
 }
 
+Error MountMem::Access(const Path& path, int a_mode) {
+  AutoLock lock(&lock_);
+  MountNode* node = NULL;
+  Error error = FindNode(path, 0, &node);
+
+  if (error)
+    return error;
+
+  int obj_mode = node->GetMode();
+  if (((a_mode & R_OK) && !(obj_mode & S_IREAD)) ||
+      ((a_mode & W_OK) && !(obj_mode & S_IWRITE)) ||
+      ((a_mode & X_OK) && !(obj_mode & S_IEXEC))) {

[binji, 2013/06/19 16:46:28]

no exec

[Matt Giuca, 2013/06/20 01:43:14]

See comment on mount_html5fs.

Also note that regardless of the outcome of that discussion, I think this code
makes sense. This isn't saying that files are executable, this is saying that if
the EXEC bit is set on a given file, Access with X_OK will succeed. Currently,
that bit is never set, so it will always fail, but given that there *is* an EXEC
bit in the memfs data structure, it is correct to test it here.

[binji, 2013/06/20 16:07:21]

OK

+    return EACCES;
+  }
+
+  return 0;
+}
+
 Error MountMem::Open(const Path& path, int mode, MountNode** out_node) {
   AutoLock lock(&lock_);
   MountNode* node = NULL;
   *out_node = NULL;
 
   Error error = FindNode(path, 0, &node);
 
   if (error) {
     // If the node does not exist and we can't create it, fail
     if ((mode & O_CREAT) == 0)
@@ skipping 131 matching lines @@
     return ENOTDIR;
 
   if (file_only && child->IsaDir())
     return EISDIR;
 
   if (remove_dir && child->ChildCount() > 0)
     return ENOTEMPTY;
 
   return parent->RemoveChild(path.Basename());
 }