1 // Copyright (c) 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 CHROME_BROWSER_MAC_RELAUNCHER_H_ 6 #define CHROME_BROWSER_MAC_RELAUNCHER_H_ 7 8 // mac_relauncher implements main browser application relaunches on the Mac. 9 // When a browser wants to relaunch itself, it can't simply fork off a new 10 // process and exec a new browser from within. That leaves open a window 11 // during which two browser applications might be running concurrently. If 12 // that happens, each will wind up with a distinct Dock icon, which is 13 // especially bad if the user expected the Dock icon to be persistent by 14 // choosing Keep in Dock from the icon's contextual menu. 15 // 16 // mac_relauncher approaches this problem by introducing an intermediate 17 // process (the "relauncher") in between the original browser ("parent") and 18 // replacement browser ("relaunched"). The helper executable is used for the 19 // relauncher process; because it's an LSUIElement, it doesn't get a Dock 20 // icon and isn't visible as a running application at all. The parent will 21 // start a relauncher process, giving it the "writer" side of a pipe that it 22 // retains the "reader" end of. When the relauncher starts up, it will 23 // establish a kqueue to wait for the parent to exit, and will then write to 24 // the pipe. The parent, upon reading from the pipe, is free to exit. When the 25 // relauncher is notified via its kqueue that the parent has exited, it 26 // proceeds, launching the relaunched process. The handshake to synchronize 27 // the parent with the relauncher is necessary to avoid races: the relauncher 28 // needs to be sure that it's monitoring the parent and not some other process 29 // in light of PID reuse, so the parent must remain alive long enough for the 30 // relauncher to set up its kqueue. 31 32 #include <string> 33 #include <vector> 34 35 namespace content { 36 struct MainFunctionParams; 37 } 38 39 namespace mac_relauncher { 40 41 // The relauncher process can unmount and eject a mounted disk image and move 42 // its disk image file to the trash. This argument may be supplied to 43 // RelaunchAppWithHelper to achieve this. The argument's value must be a BSD 44 // device name of the form "diskN" or "diskNsM". 45 extern const char* const kRelauncherDMGDeviceArg; 46 47 // Relaunches the application using the helper application associated with the 48 // currently running instance of Chrome in the parent browser process as the 49 // executable for the relauncher process. |args| is an argv-style vector of 50 // command line arguments of the form normally passed to execv. args[0] is 51 // also the path to the relaunched process. Because the relauncher process 52 // will ultimately launch the relaunched process via Launch Services, args[0] 53 // may be either a pathname to an executable file or a pathname to an .app 54 // bundle directory. The caller should exit soon after RelaunchApp returns 55 // successfully. Returns true on success, although some failures can occur 56 // after this function returns true if, for example, they occur within the 57 // relauncher process. Returns false when the relaunch definitely failed. 58 bool RelaunchApp(const std::vector<std::string>& args); 59 60 // Identical to RelaunchApp, but uses |helper| as the path to the relauncher 61 // process, and allows additional arguments to be supplied to the relauncher 62 // process in relauncher_args. Unlike args[0], |helper| must be a pathname to 63 // an executable file. The helper path given must be from the same version of 64 // Chrome as the running parent browser process, as there are no guarantees 65 // that the parent and relauncher processes from different versions will be 66 // able to communicate with one another. This variant can be useful to 67 // relaunch the same version of Chrome from another location, using that 68 // location's helper. 69 bool RelaunchAppWithHelper(const std::string& helper, 70 const std::vector<std::string>& relauncher_args, 71 const std::vector<std::string>& args); 72 73 namespace internal { 74 75 // The entry point from ChromeMain into the relauncher process. This is not a 76 // user API. Don't call it if your name isn't ChromeMain. 77 int RelauncherMain(const content::MainFunctionParams& main_parameters); 78 79 } // namespace internal 80 81 } // namespace mac_relauncher 82 83 #endif // CHROME_BROWSER_MAC_RELAUNCHER_H_ 84