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 #if defined(OS_MACOSX) 19 #include "base/feature_list.h" 20 #include "base/process/port_provider_mac.h" 21 #endif 22 23 namespace base { 24 25 #if defined(OS_MACOSX) 26 extern const Feature kMacAllowBackgroundingProcesses; 27 #endif 28 29 // Provides a move-only encapsulation of a process. 30 // 31 // This object is not tied to the lifetime of the underlying process: the 32 // process may be killed and this object may still around, and it will still 33 // claim to be valid. The actual behavior in that case is OS dependent like so: 34 // 35 // Windows: The underlying ProcessHandle will be valid after the process dies 36 // and can be used to gather some information about that process, but most 37 // methods will obviously fail. 38 // 39 // POSIX: The underlying PorcessHandle is not guaranteed to remain valid after 40 // the process dies, and it may be reused by the system, which means that it may 41 // end up pointing to the wrong process. 42 class BASE_EXPORT Process { 43 public: 44 explicit Process(ProcessHandle handle = kNullProcessHandle); 45 46 Process(Process&& other); 47 48 // The destructor does not terminate the process. 49 ~Process(); 50 51 Process& operator=(Process&& other); 52 53 // Returns an object for the current process. 54 static Process Current(); 55 56 // Returns a Process for the given |pid|. 57 static Process Open(ProcessId pid); 58 59 // Returns a Process for the given |pid|. On Windows the handle is opened 60 // with more access rights and must only be used by trusted code (can read the 61 // address space and duplicate handles). 62 static Process OpenWithExtraPrivileges(ProcessId pid); 63 64 #if defined(OS_WIN) 65 // Returns a Process for the given |pid|, using some |desired_access|. 66 // See ::OpenProcess documentation for valid |desired_access|. 67 static Process OpenWithAccess(ProcessId pid, DWORD desired_access); 68 #endif 69 70 // Creates an object from a |handle| owned by someone else. 71 // Don't use this for new code. It is only intended to ease the migration to 72 // a strict ownership model. 73 // TODO(rvargas) crbug.com/417532: Remove this code. 74 static Process DeprecatedGetProcessFromHandle(ProcessHandle handle); 75 76 // Returns true if processes can be backgrounded. 77 static bool CanBackgroundProcesses(); 78 79 // Terminates the current process immediately with |exit_code|. 80 static void TerminateCurrentProcessImmediately(int exit_code); 81 82 // Returns true if this objects represents a valid process. 83 bool IsValid() const; 84 85 // Returns a handle for this process. There is no guarantee about when that 86 // handle becomes invalid because this object retains ownership. 87 ProcessHandle Handle() const; 88 89 // Returns a second object that represents this process. 90 Process Duplicate() const; 91 92 // Get the PID for this process. 93 ProcessId Pid() const; 94 95 // Returns true if this process is the current process. 96 bool is_current() const; 97 98 // Close the process handle. This will not terminate the process. 99 void Close(); 100 101 // Terminates the process with extreme prejudice. The given |exit_code| will 102 // be the exit code of the process. If |wait| is true, this method will wait 103 // for up to one minute for the process to actually terminate. 104 // Returns true if the process terminates within the allowed time. 105 // NOTE: On POSIX |exit_code| is ignored. 106 bool Terminate(int exit_code, bool wait) const; 107 108 // Waits for the process to exit. Returns true on success. 109 // On POSIX, if the process has been signaled then |exit_code| is set to -1. 110 // On Linux this must be a child process, however on Mac and Windows it can be 111 // any process. 112 // NOTE: |exit_code| is optional, nullptr can be passed if the exit code is 113 // not required. 114 bool WaitForExit(int* exit_code) const; 115 116 // Same as WaitForExit() but only waits for up to |timeout|. 117 // NOTE: |exit_code| is optional, nullptr can be passed if the exit code 118 // is not required. 119 bool WaitForExitWithTimeout(TimeDelta timeout, int* exit_code) const; 120 121 #if defined(OS_MACOSX) 122 // The Mac needs a Mach port in order to manipulate a process's priority, 123 // and there's no good way to get that from base given the pid. These Mac 124 // variants of the IsProcessBackgrounded and SetProcessBackgrounded API take 125 // a port provider for this reason. See crbug.com/460102 126 // 127 // A process is backgrounded when its task priority is 128 // |TASK_BACKGROUND_APPLICATION|. 129 // 130 // Returns true if the port_provider can locate a task port for the process 131 // and it is backgrounded. If port_provider is null, returns false. 132 bool IsProcessBackgrounded(PortProvider* port_provider) const; 133 134 // Set the process as backgrounded. If value is 135 // true, the priority of the associated task will be set to 136 // TASK_BACKGROUND_APPLICATION. If value is false, the 137 // priority of the process will be set to TASK_FOREGROUND_APPLICATION. 138 // 139 // Returns true if the priority was changed, false otherwise. If 140 // |port_provider| is null, this is a no-op and it returns false. 141 bool SetProcessBackgrounded(PortProvider* port_provider, bool value); 142 #else 143 // A process is backgrounded when it's priority is lower than normal. 144 // Return true if this process is backgrounded, false otherwise. 145 bool IsProcessBackgrounded() const; 146 147 // Set a process as backgrounded. If value is true, the priority of the 148 // process will be lowered. If value is false, the priority of the process 149 // will be made "normal" - equivalent to default process priority. 150 // Returns true if the priority was changed, false otherwise. 151 bool SetProcessBackgrounded(bool value); 152 #endif // defined(OS_MACOSX) 153 // Returns an integer representing the priority of a process. The meaning 154 // of this value is OS dependent. 155 int GetPriority() const; 156 157 #if defined(OS_CHROMEOS) 158 // Get the PID in its PID namespace. 159 // If the process is not in a PID namespace or /proc/<pid>/status does not 160 // report NSpid, kNullProcessId is returned. 161 ProcessId GetPidInNamespace() const; 162 #endif 163 164 private: 165 #if defined(OS_WIN) 166 bool is_current_process_; 167 win::ScopedHandle process_; 168 #else 169 ProcessHandle process_; 170 #endif 171 172 DISALLOW_COPY_AND_ASSIGN(Process); 173 }; 174 175 #if defined(OS_CHROMEOS) 176 // Exposed for testing. 177 // Given the contents of the /proc/<pid>/cgroup file, determine whether the 178 // process is backgrounded or not. 179 BASE_EXPORT bool IsProcessBackgroundedCGroup( 180 const StringPiece& cgroup_contents); 181 #endif // defined(OS_CHROMEOS) 182 183 } // namespace base 184 185 #endif // BASE_PROCESS_PROCESS_H_ 186