1 // Copyright 2011 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 BASE_PROCESS_PROCESS_H_ 6 #define BASE_PROCESS_PROCESS_H_ 7 8 #include "base/base_export.h" 9 #include "base/macros.h" 10 #include "base/process/process_handle.h" 11 #include "base/time/time.h" 12 #include "build/build_config.h" 13 14 #if defined(OS_WIN) 15 #include "base/win/scoped_handle.h" 16 #endif 17 18 namespace base { 19 20 // Provides a move-only encapsulation of a process. 21 // 22 // This object is not tied to the lifetime of the underlying process: the 23 // process may be killed and this object may still around, and it will still 24 // claim to be valid. The actual behavior in that case is OS dependent like so: 25 // 26 // Windows: The underlying ProcessHandle will be valid after the process dies 27 // and can be used to gather some information about that process, but most 28 // methods will obviously fail. 29 // 30 // POSIX: The underlying PorcessHandle is not guaranteed to remain valid after 31 // the process dies, and it may be reused by the system, which means that it may 32 // end up pointing to the wrong process. 33 class BASE_EXPORT Process { 34 public: 35 explicit Process(ProcessHandle handle = kNullProcessHandle); 36 37 Process(Process&& other); 38 39 // The destructor does not terminate the process. 40 ~Process(); 41 42 Process& operator=(Process&& other); 43 44 // Returns an object for the current process. 45 static Process Current(); 46 47 // Returns a Process for the given |pid|. 48 static Process Open(ProcessId pid); 49 50 // Returns a Process for the given |pid|. On Windows the handle is opened 51 // with more access rights and must only be used by trusted code (can read the 52 // address space and duplicate handles). 53 static Process OpenWithExtraPrivileges(ProcessId pid); 54 55 #if defined(OS_WIN) 56 // Returns a Process for the given |pid|, using some |desired_access|. 57 // See ::OpenProcess documentation for valid |desired_access|. 58 static Process OpenWithAccess(ProcessId pid, DWORD desired_access); 59 #endif 60 61 // Creates an object from a |handle| owned by someone else. 62 // Don't use this for new code. It is only intended to ease the migration to 63 // a strict ownership model. 64 // TODO(rvargas) crbug.com/417532: Remove this code. 65 static Process DeprecatedGetProcessFromHandle(ProcessHandle handle); 66 67 // Returns true if processes can be backgrounded. 68 static bool CanBackgroundProcesses(); 69 70 // Returns true if this objects represents a valid process. 71 bool IsValid() const; 72 73 // Returns a handle for this process. There is no guarantee about when that 74 // handle becomes invalid because this object retains ownership. 75 ProcessHandle Handle() const; 76 77 // Returns a second object that represents this process. 78 Process Duplicate() const; 79 80 // Get the PID for this process. 81 ProcessId Pid() const; 82 83 // Returns true if this process is the current process. 84 bool is_current() const; 85 86 // Close the process handle. This will not terminate the process. 87 void Close(); 88 89 // Terminates the process with extreme prejudice. The given |exit_code| will 90 // be the exit code of the process. If |wait| is true, this method will wait 91 // for up to one minute for the process to actually terminate. 92 // Returns true if the process terminates within the allowed time. 93 // NOTE: On POSIX |exit_code| is ignored. 94 bool Terminate(int exit_code, bool wait) const; 95 96 // Waits for the process to exit. Returns true on success. 97 // On POSIX, if the process has been signaled then |exit_code| is set to -1. 98 // On Linux this must be a child process, however on Mac and Windows it can be 99 // any process. 100 // NOTE: |exit_code| is optional, nullptr can be passed if the exit code is 101 // not required. 102 bool WaitForExit(int* exit_code); 103 104 // Same as WaitForExit() but only waits for up to |timeout|. 105 // NOTE: |exit_code| is optional, nullptr can be passed if the exit code 106 // is not required. 107 bool WaitForExitWithTimeout(TimeDelta timeout, int* exit_code); 108 109 // A process is backgrounded when it's priority is lower than normal. 110 // Return true if this process is backgrounded, false otherwise. 111 bool IsProcessBackgrounded() const; 112 113 // Set a process as backgrounded. If value is true, the priority of the 114 // process will be lowered. If value is false, the priority of the process 115 // will be made "normal" - equivalent to default process priority. 116 // Returns true if the priority was changed, false otherwise. 117 bool SetProcessBackgrounded(bool value); 118 119 // Returns an integer representing the priority of a process. The meaning 120 // of this value is OS dependent. 121 int GetPriority() const; 122 123 #if defined(OS_CHROMEOS) 124 // Get the PID in its PID namespace. 125 // If the process is not in a PID namespace or /proc/<pid>/status does not 126 // report NSpid, kNullProcessId is returned. 127 ProcessId GetPidInNamespace() const; 128 #endif 129 130 private: 131 #if defined(OS_WIN) 132 bool is_current_process_; 133 win::ScopedHandle process_; 134 #else 135 ProcessHandle process_; 136 #endif 137 138 DISALLOW_COPY_AND_ASSIGN(Process); 139 }; 140 141 #if defined(OS_CHROMEOS) 142 // Exposed for testing. 143 // Given the contents of the /proc/<pid>/cgroup file, determine whether the 144 // process is backgrounded or not. 145 BASE_EXPORT bool IsProcessBackgroundedCGroup( 146 const StringPiece& cgroup_contents); 147 #endif // defined(OS_CHROMEOS) 148 149 } // namespace base 150 151 #endif // BASE_PROCESS_PROCESS_H_ 152