headless: Make it possible to override the DevTools server address

headless/app/headless_shell.cc

 // Copyright 2016 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 <memory>
 
 #include "base/bind.h"
 #include "base/callback.h"
 #include "base/command_line.h"
 #include "base/location.h"
@@ skipping 83 matching lines @@
   DISALLOW_COPY_AND_ASSIGN(HeadlessShell);
 };
 
 int main(int argc, const char** argv) {
   HeadlessShell shell;
   HeadlessBrowser::Options::Builder builder(argc, argv);
 
   // Enable devtools if requested.
   base::CommandLine command_line(argc, argv);
   if (command_line.HasSwitch(switches::kRemoteDebuggingPort)) {
+    std::string address = kDevToolsHttpServerAddress;
+    if (command_line.HasSwitch(headless::switches::kRemoteDebuggingAddress)) {
+      address = command_line.GetSwitchValueASCII(
+          headless::switches::kRemoteDebuggingAddress);

[Mike West, 2016/04/26 08:04:37]

It seems reasonable to do some sanity checking here; maybe look at using
`net::ParseURLHostnameToAddress` to verify that the string you're given is
actually an IP address? Otherwise you'll potentially be in a bad state after the
call to assign the IP address to devtools below (the DCHECK wouldn't crash you
in non-debug mode).

[Sami, 2016/04/26 10:07:52]

Good point. I've now made this use net::ParseURLHostnameToAddress and to bail
out if that doesn't like the input (plus the same for port parsing).

+    }
     int parsed_port;
     std::string port_str =
         command_line.GetSwitchValueASCII(switches::kRemoteDebuggingPort);
     if (base::StringToInt(port_str, &parsed_port) &&
         base::IsValueInRangeForNumericType<uint16_t>(parsed_port)) {
       net::IPAddress devtools_address;
-      bool result =
-          devtools_address.AssignFromIPLiteral(kDevToolsHttpServerAddress);
+      bool result = devtools_address.AssignFromIPLiteral(address);
       DCHECK(result);
       builder.EnableDevToolsServer(net::IPEndPoint(
           devtools_address, base::checked_cast<uint16_t>(parsed_port)));
     }
   }
 
   if (command_line.HasSwitch(headless::switches::kProxyServer)) {
     std::string proxy_server =
         command_line.GetSwitchValueASCII(headless::switches::kProxyServer);
     net::HostPortPair parsed_proxy_server =
         net::HostPortPair::FromString(proxy_server);
     if (parsed_proxy_server.host().empty() || !parsed_proxy_server.port()) {
       LOG(ERROR) << "Malformed proxy server url";
       return EXIT_FAILURE;
     }
     builder.SetProxyServer(parsed_proxy_server);
   }
 
   if (command_line.HasSwitch(switches::kHostResolverRules)) {
     builder.SetHostResolverRules(
         command_line.GetSwitchValueASCII(switches::kHostResolverRules));
   }
 
   return HeadlessBrowserMain(
       builder.Build(),
       base::Bind(&HeadlessShell::OnStart, base::Unretained(&shell)));
 }