content/public/common/zygote_fork_delegate_linux.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_PUBLIC_COMMON_ZYGOTE_FORK_DELEGATE_LINUX_H_
   6 #define CONTENT_PUBLIC_COMMON_ZYGOTE_FORK_DELEGATE_LINUX_H_
   7
   8 #include <unistd.h>
   9
  10 #include <string>
  11 #include <vector>
  12
  13 namespace content {
  14
  15 // The ZygoteForkDelegate allows the Chrome Linux zygote to delegate
  16 // fork operations to another class that knows how to do some
  17 // specialized version of fork.
  18 class ZygoteForkDelegate {
  19  public:
  20   // A ZygoteForkDelegate is created during Chrome linux zygote
  21   // initialization, and provides "fork()" functionality as an
  22   // alternative to forking the zygote.  A new delegate is passed in
  23   // as an argument to ZygoteMain().
  24   virtual ~ZygoteForkDelegate() {}
  25
  26   // Initialization happens in the zygote after it has been
  27   // started by ZygoteMain.
  28   virtual void Init(bool sandboxed,
  29                     int browserdesc,
  30                     int sandboxdesc) = 0;
  31
  32   // After Init, supply a UMA_HISTOGRAM_ENUMERATION the delegate
  33   // would like to supply on the first fork.
  34   virtual void InitialUMA(std::string* uma_name,
  35                           int* uma_sample,
  36                           int* uma_boundary_value) = 0;
  37
  38   // Returns 'true' if the delegate would like to handle a given fork
  39   // request.  Otherwise returns false.  Optionally, fills in uma_name et al
  40   // with a report the helper wants to make via UMA_HISTOGRAM_ENUMERATION.
  41   virtual bool CanHelp(const std::string& process_type, std::string* uma_name,
  42                        int* uma_sample, int* uma_boundary_value) = 0;
  43
  44   // Delegate forks, returning a -1 on failure. Outside the
  45   // suid sandbox, Fork() returns the Linux process ID. Inside
  46   // the sandbox, returns a positive integer, with PID discovery
  47   // handled by the sandbox.
  48   virtual pid_t Fork(const std::vector<int>& fds) = 0;
  49
  50   // After a successful for, signal the child to indicate that
  51   // the child's PID has been received. Also communicate the
  52   // channel switch as a part of acknowledgement message.
  53   virtual bool AckChild(int fd, const std::string& channel_switch) = 0;
  54 };
  55
  56 }  // namespace content
  57
  58 #endif  // CONTENT_PUBLIC_COMMON_ZYGOTE_FORK_DELEGATE_LINUX_H_