80 lines
4.2 KiB
C++
80 lines
4.2 KiB
C++
// Copyright (c) 2016 GitHub, Inc.
|
|
// Use of this source code is governed by the MIT license that can be
|
|
// found in the LICENSE file.
|
|
|
|
#ifndef ATOM_BROWSER_RELAUNCHER_H_
|
|
#define ATOM_BROWSER_RELAUNCHER_H_
|
|
|
|
// relauncher implements main browser application relaunches across platforms.
|
|
// When a browser wants to relaunch itself, it can't simply fork off a new
|
|
// process and exec a new browser from within. That leaves open a window
|
|
// during which two browser applications might be running concurrently. If
|
|
// that happens, each will wind up with a distinct Dock icon, which is
|
|
// especially bad if the user expected the Dock icon to be persistent by
|
|
// choosing Keep in Dock from the icon's contextual menu.
|
|
//
|
|
// relauncher approaches this problem by introducing an intermediate
|
|
// process (the "relauncher") in between the original browser ("parent") and
|
|
// replacement browser ("relaunched"). The helper executable is used for the
|
|
// relauncher process; because it's an LSUIElement, it doesn't get a Dock
|
|
// icon and isn't visible as a running application at all. The parent will
|
|
// start a relauncher process, giving it the "writer" side of a pipe that it
|
|
// retains the "reader" end of. When the relauncher starts up, it will
|
|
// establish a kqueue to wait for the parent to exit, and will then write to
|
|
// the pipe. The parent, upon reading from the pipe, is free to exit. When the
|
|
// relauncher is notified via its kqueue that the parent has exited, it
|
|
// proceeds, launching the relaunched process. The handshake to synchronize
|
|
// the parent with the relauncher is necessary to avoid races: the relauncher
|
|
// needs to be sure that it's monitoring the parent and not some other process
|
|
// in light of PID reuse, so the parent must remain alive long enough for the
|
|
// relauncher to set up its kqueue.
|
|
|
|
#include <string>
|
|
#include <vector>
|
|
|
|
namespace content {
|
|
struct MainFunctionParams;
|
|
}
|
|
|
|
namespace relauncher {
|
|
|
|
// Relaunches the application using the helper application associated with the
|
|
// currently running instance of Chrome in the parent browser process as the
|
|
// executable for the relauncher process. |args| is an argv-style vector of
|
|
// command line arguments of the form normally passed to execv. args[0] is
|
|
// also the path to the relaunched process. Because the relauncher process
|
|
// will ultimately launch the relaunched process via Launch Services, args[0]
|
|
// may be either a pathname to an executable file or a pathname to an .app
|
|
// bundle directory. The caller should exit soon after RelaunchApp returns
|
|
// successfully. Returns true on success, although some failures can occur
|
|
// after this function returns true if, for example, they occur within the
|
|
// relauncher process. Returns false when the relaunch definitely failed.
|
|
bool RelaunchApp(const std::vector<std::string>& args);
|
|
|
|
// Identical to RelaunchApp, but uses |helper| as the path to the relauncher
|
|
// process, and allows additional arguments to be supplied to the relauncher
|
|
// process in relauncher_args. Unlike args[0], |helper| must be a pathname to
|
|
// an executable file. The helper path given must be from the same version of
|
|
// Chrome as the running parent browser process, as there are no guarantees
|
|
// that the parent and relauncher processes from different versions will be
|
|
// able to communicate with one another. This variant can be useful to
|
|
// relaunch the same version of Chrome from another location, using that
|
|
// location's helper.
|
|
bool RelaunchAppWithHelper(const std::string& helper,
|
|
const std::vector<std::string>& relauncher_args,
|
|
const std::vector<std::string>& args);
|
|
|
|
// In the relauncher process, performs the necessary synchronization steps
|
|
// with the parent by setting up a kqueue to watch for it to exit, writing a
|
|
// byte to the pipe, and then waiting for the exit notification on the kqueue.
|
|
// If anything fails, this logs a message and returns immediately. In those
|
|
// situations, it can be assumed that something went wrong with the parent
|
|
// process and the best recovery approach is to attempt relaunch anyway.
|
|
void RelauncherSynchronizeWithParent();
|
|
|
|
// The entry point from ChromeMain into the relauncher process.
|
|
int RelauncherMain(const content::MainFunctionParams& main_parameters);
|
|
|
|
} // namespace relauncher
|
|
|
|
#endif // ATOM_BROWSER_RELAUNCHER_H_
|