content/browser/child_process_launcher.h

   1 // Copyright (c) 2012 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 #ifndef CONTENT_BROWSER_CHILD_PROCESS_LAUNCHER_H_
   6 #define CONTENT_BROWSER_CHILD_PROCESS_LAUNCHER_H_
   7
   8 #include "base/basictypes.h"
   9 #include "base/memory/ref_counted.h"
  10 #include "base/process/kill.h"
  11 #include "base/process/launch.h"
  12 #include "content/common/content_export.h"
  13
  14 class CommandLine;
  15
  16 namespace content {
  17 class SandboxedProcessLauncherDelegate;
  18
  19 // Launches a process asynchronously and notifies the client of the process
  20 // handle when it's available.  It's used to avoid blocking the calling thread
  21 // on the OS since often it can take > 100 ms to create the process.
  22 class CONTENT_EXPORT ChildProcessLauncher {
  23  public:
  24   class CONTENT_EXPORT Client {
  25    public:
  26     // Will be called on the thread that the ChildProcessLauncher was
  27     // constructed on.
  28     virtual void OnProcessLaunched() = 0;
  29
  30    protected:
  31     virtual ~Client() {}
  32   };
  33
  34   // Launches the process asynchronously, calling the client when the result is
  35   // ready.  Deleting this object before the process is created is safe, since
  36   // the callback won't be called.  If the process is still running by the time
  37   // this object destructs, it will be terminated.
  38   // Takes ownership of cmd_line.
  39   ChildProcessLauncher(
  40 #if defined(OS_WIN)
  41       SandboxedProcessLauncherDelegate* delegate,
  42 #elif defined(OS_POSIX)
  43       bool use_zygote,
  44       const base::EnvironmentMap& environ,
  45       int ipcfd,
  46 #endif
  47       CommandLine* cmd_line,
  48       int child_process_id,
  49       Client* client);
  50   ~ChildProcessLauncher();
  51
  52   // True if the process is being launched and so the handle isn't available.
  53   bool IsStarting();
  54
  55   // Getter for the process handle.  Only call after the process has started.
  56   base::ProcessHandle GetHandle();
  57
  58   // Call this when the child process exits to know what happened to it.
  59   // |known_dead| can be true if we already know the process is dead as it can
  60   // help the implemention figure the proper TerminationStatus.
  61   // On Linux, the use of |known_dead| is subtle and can be crucial if an
  62   // accurate status is important. With |known_dead| set to false, a dead
  63   // process could be seen as running. With |known_dead| set to true, the
  64   // process will be killed if it was still running. See ZygoteHostImpl for
  65   // more discussion of Linux implementation details.
  66   // |exit_code| is the exit code of the process if it exited (e.g. status from
  67   // waitpid if on posix, from GetExitCodeProcess on Windows). |exit_code| may
  68   // be NULL.
  69   base::TerminationStatus GetChildTerminationStatus(bool known_dead,
  70                                                     int* exit_code);
  71
  72   // Changes whether the process runs in the background or not.  Only call
  73   // this after the process has started.
  74   void SetProcessBackgrounded(bool background);
  75
  76   // Controls whether the child process should be terminated on browser
  77   // shutdown.
  78   void SetTerminateChildOnShutdown(bool terminate_on_shutdown);
  79
  80  private:
  81   class Context;
  82
  83   scoped_refptr<Context> context_;
  84
  85   DISALLOW_COPY_AND_ASSIGN(ChildProcessLauncher);
  86 };
  87
  88 }  // namespace content
  89
  90 #endif  // CONTENT_BROWSER_CHILD_PROCESS_LAUNCHER_H_