chrome/app/chrome_watcher_command_line_win.cc

   1 // Copyright (c) 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/app/chrome_watcher_command_line_win.h"
   6
   7 #include <string>
   8
   9 #include "base/command_line.h"
  10 #include "base/files/file_path.h"
  11 #include "base/logging.h"
  12 #include "base/strings/string_number_conversions.h"
  13 #include "base/strings/stringprintf.h"
  14 #include "chrome/common/chrome_switches.h"
  15
  16 namespace {
  17
  18 const char kOnIninitializedEventHandleSwitch[] = "on-initialized-event-handle";
  19 const char kParentHandleSwitch[] = "parent-handle";
  20
  21 void AppendHandleSwitch(const std::string& switch_name,
  22                         HANDLE handle,
  23                         base::CommandLine* command_line) {
  24   command_line->AppendSwitchASCII(
  25       switch_name, base::UintToString(reinterpret_cast<unsigned int>(handle)));
  26 }
  27
  28 HANDLE ReadHandleFromSwitch(const base::CommandLine& command_line,
  29                             const std::string& switch_name) {
  30   std::string switch_string = command_line.GetSwitchValueASCII(switch_name);
  31   unsigned int switch_uint = 0;
  32   if (switch_string.empty() ||
  33       !base::StringToUint(switch_string, &switch_uint)) {
  34     DLOG(ERROR) << "Missing or invalid " << switch_name << " argument.";
  35     return nullptr;
  36   }
  37   return reinterpret_cast<HANDLE>(switch_uint);
  38 }
  39
  40 }  // namespace
  41
  42 base::CommandLine GenerateChromeWatcherCommandLine(
  43     const base::FilePath& chrome_exe,
  44     HANDLE parent_process,
  45     HANDLE on_initialized_event) {
  46   base::CommandLine command_line(chrome_exe);
  47   command_line.AppendSwitchASCII(switches::kProcessType, "watcher");
  48   AppendHandleSwitch(kOnIninitializedEventHandleSwitch, on_initialized_event,
  49                      &command_line);
  50   AppendHandleSwitch(kParentHandleSwitch, parent_process, &command_line);
  51   return command_line;
  52 }
  53
  54 bool InterpretChromeWatcherCommandLine(
  55     const base::CommandLine& command_line,
  56     base::win::ScopedHandle* parent_process,
  57     base::win::ScopedHandle* on_initialized_event) {
  58   DCHECK(on_initialized_event);
  59   DCHECK(parent_process);
  60
  61   // For consistency, always close any existing HANDLEs here.
  62   on_initialized_event->Close();
  63   parent_process->Close();
  64
  65   HANDLE parent_handle =
  66       ReadHandleFromSwitch(command_line, kParentHandleSwitch);
  67   HANDLE on_initialized_event_handle =
  68       ReadHandleFromSwitch(command_line, kOnIninitializedEventHandleSwitch);
  69
  70   if (parent_handle) {
  71     // Initial test of the handle, a zero PID indicates invalid handle, or not
  72     // a process handle. In this case, parsing fails and we avoid closing the
  73     // handle.
  74     DWORD process_pid = ::GetProcessId(parent_handle);
  75     if (process_pid == 0) {
  76       DLOG(ERROR) << "Invalid " << kParentHandleSwitch
  77                   << " argument. Can't get parent PID.";
  78     } else {
  79       parent_process->Set(parent_handle);
  80     }
  81   }
  82
  83   if (on_initialized_event_handle) {
  84     DWORD result = ::WaitForSingleObject(on_initialized_event_handle, 0);
  85     if (result == WAIT_FAILED) {
  86       DPLOG(ERROR)
  87           << "Unexpected error while testing the initialization event.";
  88     } else if (result != WAIT_TIMEOUT) {
  89       DLOG(ERROR) << "Unexpected result while testing the initialization event "
  90                      "with WaitForSingleObject: " << result;
  91     } else {
  92       on_initialized_event->Set(on_initialized_event_handle);
  93     }
  94   }
  95
  96   if (!on_initialized_event->IsValid() || !parent_process->IsValid()) {
  97     // If one was valid and not the other, free the valid one.
  98     on_initialized_event->Close();
  99     parent_process->Close();
 100     return false;
 101   }
 102
 103   return true;
 104 }