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 // TODO(jln) base::TerminationStatus should be forward declared when switching 14 // to C++11. 15 #include "base/process/kill.h" 16 17 namespace content { 18 19 // The ZygoteForkDelegate allows the Chrome Linux zygote to delegate 20 // fork operations to another class that knows how to do some 21 // specialized version of fork. 22 class ZygoteForkDelegate { 23 public: 24 // A ZygoteForkDelegate is created during Chrome linux zygote 25 // initialization, and provides "fork()" functionality as an 26 // alternative to forking the zygote. A new delegate is passed in 27 // as an argument to ZygoteMain(). 28 virtual ~ZygoteForkDelegate() {} 29 30 // Initialization happens in the zygote after it has been 31 // started by ZygoteMain. 32 virtual void Init(int sandboxdesc) = 0; 33 34 // After Init, supply a UMA_HISTOGRAM_ENUMERATION the delegate 35 // would like to supply on the first fork. 36 virtual void InitialUMA(std::string* uma_name, 37 int* uma_sample, 38 int* uma_boundary_value) = 0; 39 40 // Returns 'true' if the delegate would like to handle a given fork 41 // request. Otherwise returns false. Optionally, fills in uma_name et al 42 // with a report the helper wants to make via UMA_HISTOGRAM_ENUMERATION. 43 virtual bool CanHelp(const std::string& process_type, std::string* uma_name, 44 int* uma_sample, int* uma_boundary_value) = 0; 45 46 // Indexes of FDs in the vector passed to Fork(). 47 enum { 48 // Used to pass in the descriptor for talking to the Browser 49 kBrowserFDIndex, 50 // The next two are used in the protocol for discovering the 51 // child processes real PID from within the SUID sandbox. See 52 // http://code.google.com/p/chromium/wiki/LinuxZygote 53 kDummyFDIndex, 54 kParentFDIndex, 55 kNumPassedFDs // Number of FDs in the vector passed to Fork(). 56 }; 57 58 // Delegate forks, returning a -1 on failure. Outside the 59 // suid sandbox, Fork() returns the Linux process ID. 60 // This method is not aware of any potential pid namespaces, so it'll 61 // return a raw pid just like fork() would. 62 virtual pid_t Fork(const std::vector<int>& fds) = 0; 63 64 // After a successful fork, signal the child to indicate that 65 // the child's PID has been received. Also communicate the 66 // channel switch as a part of acknowledgement message. 67 virtual bool AckChild(int fd, const std::string& channel_switch) = 0; 68 69 // The fork delegate must also assume the role of waiting for its children 70 // since the caller will not be their parents and cannot do it. |pid| here 71 // should be a pid that has been returned by the Fork() method. i.e. This 72 // method is completely unaware of eventual PID namespaces due to sandboxing. 73 // |known_dead| indicates that the process is already dead and that a 74 // blocking wait() should be performed. In this case, GetTerminationStatus() 75 // will send a SIGKILL to the target process first. 76 virtual bool GetTerminationStatus(pid_t pid, bool known_dead, 77 base::TerminationStatus* status, 78 int* exit_code) = 0; 79 }; 80 81 } // namespace content 82 83 #endif // CONTENT_PUBLIC_COMMON_ZYGOTE_FORK_DELEGATE_LINUX_H_ 84
