[NaCl SDK] Add some more logging to nacl_io.

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

 // Copyright 2013 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/devfs/tty_node.h"
 
 #include <assert.h>
 #include <errno.h>
 #include <signal.h>
 #include <stdio.h>
@@ skipping 71 matching lines @@
 }
 
 Error TtyNode::Write(const HandleAttr& attr,
                      const void* buf,
                      size_t count,
                      int* out_bytes) {
   AUTO_LOCK(output_lock_);
   *out_bytes = 0;
 
   // No handler registered.
-  if (output_handler_.handler == NULL)
+  if (output_handler_.handler == NULL) {
+    // No error here; many of the tests trigger this message.
+    LOG_TRACE("No output handler registered.");
     return EIO;
+  }
 
   int rtn = output_handler_.handler(
       static_cast<const char*>(buf), count, output_handler_.user_data);
 
   // Negative return value means an error occured and the return
   // value is a negated errno value.
   if (rtn < 0)
     return -rtn;
 
   *out_bytes = rtn;
@@ skipping 59 matching lines @@
     // TOOD(sbc): Do something more useful in response to a
     // failure to echo.
     return error;
   }
 
   return 0;
 }
 
 Error TtyNode::ProcessInput(PP_Var message) {
   if (message.type != PP_VARTYPE_STRING) {
-    LOG_ERROR("ProcessInput: expected VarString but got %d.", message.type);
+    LOG_ERROR("Expected VarString but got %d.", message.type);
     return EINVAL;
   }
 
   PepperInterface* ppapi = filesystem_->ppapi();
   if (!ppapi) {
-    LOG_ERROR("ProcessInput: ppapi is NULL.");
+    LOG_ERROR("ppapi is NULL.");
     return EINVAL;
   }
 
   VarInterface* var_iface = ppapi->GetVarInterface();
   if (!var_iface) {
-    LOG_ERROR("ProcessInput: Var interface pointer is NULL.");
+    LOG_ERROR("Got NULL interface: Var");
     return EINVAL;
   }
 
   uint32_t num_bytes;
   const char* buffer = var_iface->VarToUtf8(message, &num_bytes);
   Error error = ProcessInput(buffer, num_bytes);
   return error;
 }
 
 Error TtyNode::ProcessInput(const char* buffer, size_t num_bytes) {
@@ skipping 62 matching lines @@
 
 Error TtyNode::VIoctl(int request, va_list args) {
   switch (request) {
     case TIOCNACLOUTPUT: {
       struct tioc_nacl_output* arg = va_arg(args, struct tioc_nacl_output*);
       AUTO_LOCK(output_lock_);
       if (arg == NULL) {
         output_handler_.handler = NULL;
         return 0;
       }
-      if (output_handler_.handler != NULL)
+      if (output_handler_.handler != NULL) {
+        LOG_ERROR("Output handler already set.");
         return EALREADY;
+      }
       output_handler_ = *arg;
       return 0;
     }
     case NACL_IOC_HANDLEMESSAGE: {
       struct PP_Var* message = va_arg(args, struct PP_Var*);
       return ProcessInput(*message);
     }
     case TIOCSWINSZ: {
       struct winsize* size = va_arg(args, struct winsize*);
       {
@@ skipping 34 matching lines @@
 }
 
 Error TtyNode::Tcsetattr(int optional_actions,
                          const struct termios* termios_p) {
   AUTO_LOCK(node_lock_);
   termios_ = *termios_p;
   return 0;
 }
 
 }  // namespace nacl_io