[NaCl SDK] Add some more logging to nacl_io.

native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.cc

Index: native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.cc b/native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.cc
index 9b50c90f8055a82ab58b8a8740cc5fa5043b2987..efe805525cc5669a58f3b87d43a529e07a264a60 100644
--- a/native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.cc
+++ b/native_client_sdk/src/libraries/nacl_io/devfs/dev_fs.cc
@@ -189,16 +189,21 @@ Error ConsoleNode::Write(const HandleAttr& attr,
                          int* out_bytes) {
   *out_bytes = 0;
 
-  ConsoleInterface* con_intr = filesystem_->ppapi()->GetConsoleInterface();
-  VarInterface* var_intr = filesystem_->ppapi()->GetVarInterface();
+  ConsoleInterface* con_iface = filesystem_->ppapi()->GetConsoleInterface();
+  VarInterface* var_iface = filesystem_->ppapi()->GetVarInterface();
 
-  if (!(var_intr && con_intr))
+  if (!(var_iface && con_iface)) {
+    LOG_ERROR("Got NULL interface(s): %s%s",
+              con_iface ? "" : "Console ",
+              var_iface ? "" : "Var");
     return ENOSYS;
+  }
 
   const char* var_data = static_cast<const char*>(buf);
   uint32_t len = static_cast<uint32_t>(count);
-  struct PP_Var val = var_intr->VarFromUtf8(var_data, len);
-  con_intr->Log(filesystem_->ppapi()->GetInstance(), level_, val);
+  struct PP_Var val = var_iface->VarFromUtf8(var_data, len);
+  con_iface->Log(filesystem_->ppapi()->GetInstance(), level_, val);
+  var_iface->Release(val);
 
   *out_bytes = count;
   return 0;
@@ -241,8 +246,10 @@ Error UrandomNode::Read(const HandleAttr& attr,
   *out_bytes = 0;
 
 #if defined(__native_client__)
-  if (!interface_ok_)
+  if (!interface_ok_) {
+    LOG_ERROR("NACL_IRT_RANDOM_v0_1 interface not avaiable.");
     return EBADF;
+  }
 
   size_t nread;
   int error = (*random_interface_.get_random_bytes)(buf, count, &nread);
@@ -295,8 +302,10 @@ Error DevFs::Access(const Path& path, int a_mode) {
     return error;
 
   // Don't allow execute access.
-  if (a_mode & X_OK)
+  if (a_mode & X_OK) {
+    LOG_TRACE("Executing devfs nodes is not allowed.");
     return EACCES;
+  }
 
   return 0;
 }
@@ -305,38 +314,47 @@ Error DevFs::Open(const Path& path, int open_flags, ScopedNode* out_node) {
   out_node->reset(NULL);
   int error;
   if (path.Part(1) == "fs") {
-    if (path.Size() == 3)
+    if (path.Size() == 3) {
       error = fs_dir_->FindChild(path.Part(2), out_node);
-    else
+    } else {
+      LOG_TRACE("Bad devfs path: %s", path.Join().c_str());
       error = ENOENT;
+    }
   } else {
     error = root_->FindChild(path.Join(), out_node);
   }
 
   // Only return EACCES when trying to create a node that does not exist.
-  if ((error == ENOENT) && (open_flags & O_CREAT))
+  if ((error == ENOENT) && (open_flags & O_CREAT)) {
+    LOG_TRACE("Cannot create devfs node: %s", path.Join().c_str());
     return EACCES;
+  }
 
   return error;
 }
 
 Error DevFs::Unlink(const Path& path) {
+  LOG_ERROR("unlink not supported.");
   return EPERM;
 }
 
 Error DevFs::Mkdir(const Path& path, int permissions) {
+  LOG_ERROR("mkdir not supported.");
   return EPERM;
 }
 
 Error DevFs::Rmdir(const Path& path) {
+  LOG_ERROR("rmdir not supported.");
   return EPERM;
 }
 
 Error DevFs::Remove(const Path& path) {
+  LOG_ERROR("remove not supported.");
   return EPERM;
 }
 
 Error DevFs::Rename(const Path& path, const Path& newpath) {
+  LOG_ERROR("rename not supported.");
   return EPERM;
 }