Make nacl_helper easily debuggable

chrome/app/nacl_fork_delegate_linux.cc

 // Copyright (c) 2011 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 "chrome/app/nacl_fork_delegate_linux.h"
 
 #include <signal.h>
 #include <stdlib.h>
 #include <sys/socket.h>
 
 #include "base/basictypes.h"
 #include "base/command_line.h"
 #include "base/eintr_wrapper.h"
 #include "base/logging.h"
 #include "base/file_path.h"
 #include "base/path_service.h"
 #include "base/process_util.h"
 #include "base/third_party/dynamic_annotations/dynamic_annotations.h"
 #include "content/common/unix_domain_socket_posix.h"
 #include "chrome/common/chrome_paths.h"
 #include "chrome/common/chrome_switches.h"
 #include "chrome/common/nacl_helper_linux.h"
 
 NaClForkDelegate::NaClForkDelegate()
     : status_(kNaClHelperUnused),
       sandboxed_(false),
       fd_(-1) {}
 
+/*
+ * Note these need to match up with their counterparts in nacl_helper_linux.c
+ * and nacl_helper_bootstrap_linux.c.
+ */
 const char kNaClHelperAtZero[] = "--at-zero";
+const char kNaClHelperRDebug[] = "--r_debug=0xXXXXXXXXXXXXXXXX";

[Mark Seaborn, 2011/11/14 20:15:41]

Maybe comment: passing this argument with a template here saves us from having
to reorganise the contents of the stack in nacl_helper_bootstrap_linux.c.

 
 void NaClForkDelegate::Init(const bool sandboxed,
                             const int browserdesc,
                             const int sandboxdesc) {
   VLOG(1) << "NaClForkDelegate::Init()";
   int fds[2];
 
   sandboxed_ = sandboxed;
   // Confirm a couple hard-wired assumptions.
   // The NaCl constants are from chrome/nacl/nacl_linux_helper.h
@@ skipping 12 matching lines @@
     status_ = kNaClHelperMissing;
   } else if (!PathService::Get(chrome::FILE_NACL_HELPER_BOOTSTRAP,
                                &helper_bootstrap_exe)) {
     status_ = kNaClHelperBootstrapMissing;
   } else if (RunningOnValgrind()) {
     status_ = kNaClHelperValgrind;
   } else {
     CommandLine cmd_line(helper_bootstrap_exe);
     cmd_line.AppendArgPath(helper_exe);
     cmd_line.AppendArgNative(kNaClHelperAtZero);
+    cmd_line.AppendArgNative(kNaClHelperRDebug);
     base::LaunchOptions options;
     options.fds_to_remap = &fds_to_map;
     options.clone_flags = CLONE_FS | SIGCHLD;
     if (!base::LaunchProcess(cmd_line.argv(), options, NULL))
       status_ = kNaClHelperLaunchFailed;
     // parent and error cases are handled below
   }
   if (HANDLE_EINTR(close(fds[1])) != 0)
     LOG(ERROR) << "close(fds[1]) failed";
   if (status_ == kNaClHelperUnused) {
@@ skipping 69 matching lines @@
 
 bool NaClForkDelegate::AckChild(const int fd,
                                 const std::string& channel_switch) {
   int nwritten = HANDLE_EINTR(write(fd, channel_switch.c_str(),
                                     channel_switch.length()));
   if (nwritten != static_cast<int>(channel_switch.length())) {
     return false;
   }
   return true;
 }