Import chrome/browser/mac/relauncher.{cc,h}

chromium_src/chrome/browser/mac/relauncher.cc

@@ -0,0 +1,381 @@
+// Copyright 2012 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "chrome/browser/mac/relauncher.h"
+
+#include <ApplicationServices/ApplicationServices.h>
+#include <AvailabilityMacros.h>
+#include <crt_externs.h>
+#include <dlfcn.h>
+#include <stddef.h>
+#include <string.h>
+#include <sys/event.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <string>
+#include <vector>
+
+#include "base/files/file_util.h"
+#include "base/files/scoped_file.h"
+#include "base/logging.h"
+#include "base/mac/mac_logging.h"
+#include "base/mac/mac_util.h"
+#include "base/mac/scoped_cftyperef.h"
+#include "base/path_service.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/process/launch.h"
+#include "base/strings/stringprintf.h"
+#include "base/strings/sys_string_conversions.h"
+#include "chrome/browser/mac/install_from_dmg.h"
+#include "chrome/common/chrome_switches.h"
+#include "content/public/common/content_paths.h"
+#include "content/public/common/content_switches.h"
+#include "content/public/common/main_function_params.h"
+
+namespace mac_relauncher {
+
+namespace {
+
+// The "magic" file descriptor that the relauncher process' write side of the
+// pipe shows up on. Chosen to avoid conflicting with stdin, stdout, and
+// stderr.
+const int kRelauncherSyncFD = STDERR_FILENO + 1;
+
+// The argument separating arguments intended for the relauncher process from
+// those intended for the relaunched process. "---" is chosen instead of "--"
+// because CommandLine interprets "--" as meaning "end of switches", but
+// for many purposes, the relauncher process' CommandLine ought to interpret
+// arguments intended for the relaunched process, to get the correct settings
+// for such things as logging and the user-data-dir in case it affects crash
+// reporting.
+const char kRelauncherArgSeparator[] = "---";
+
+// When this argument is supplied to the relauncher process, it will launch
+// the relaunched process without bringing it to the foreground.
+const char kRelauncherBackgroundArg[] = "--background";
+
+// The beginning of the "process serial number" argument that Launch Services
+// sometimes inserts into command lines. A process serial number is only valid
+// for a single process, so any PSN arguments will be stripped from command
+// lines during relaunch to avoid confusion.
+const char kPSNArg[] = "-psn_";
+
+// Returns the "type" argument identifying a relauncher process
+// ("--type=relauncher").
+std::string RelauncherTypeArg() {
+  return base::StringPrintf("--%s=%s",
+                            switches::kProcessType,
+                            switches::kRelauncherProcess);
+}
+
+}  // namespace
+
+bool RelaunchApp(const std::vector<std::string>& args) {
+  // Use the currently-running application's helper process. The automatic
+  // update feature is careful to leave the currently-running version alone,
+  // so this is safe even if the relaunch is the result of an update having
+  // been applied. In fact, it's safer than using the updated version of the
+  // helper process, because there's no guarantee that the updated version's
+  // relauncher implementation will be compatible with the running version's.
+  base::FilePath child_path;
+  if (!PathService::Get(content::CHILD_PROCESS_EXE, &child_path)) {
+    LOG(ERROR) << "No CHILD_PROCESS_EXE";
+    return false;
+  }
+
+  std::vector<std::string> relauncher_args;
+  return RelaunchAppWithHelper(child_path.value(), relauncher_args, args);
+}
+
+bool RelaunchAppWithHelper(const std::string& helper,
+                           const std::vector<std::string>& relauncher_args,
+                           const std::vector<std::string>& args) {
+  std::vector<std::string> relaunch_args;
+  relaunch_args.push_back(helper);
+  relaunch_args.push_back(RelauncherTypeArg());
+
+  // If this application isn't in the foreground, the relaunched one shouldn't
+  // be either.
+  if (!base::mac::AmIForeground()) {
+    relaunch_args.push_back(kRelauncherBackgroundArg);
+  }
+
+  relaunch_args.insert(relaunch_args.end(),
+                       relauncher_args.begin(), relauncher_args.end());
+
+  relaunch_args.push_back(kRelauncherArgSeparator);
+
+  // When using the CommandLine interface, -psn_ may have been rewritten as
+  // --psn_. Look for both.
+  const char alt_psn_arg[] = "--psn_";
+  for (size_t index = 0; index < args.size(); ++index) {
+    // Strip any -psn_ arguments, as they apply to a specific process.
+    if (args[index].compare(0, strlen(kPSNArg), kPSNArg) != 0 &&
+        args[index].compare(0, strlen(alt_psn_arg), alt_psn_arg) != 0) {
+      relaunch_args.push_back(args[index]);
+    }
+  }
+
+  int pipe_fds[2];
+  if (HANDLE_EINTR(pipe(pipe_fds)) != 0) {
+    PLOG(ERROR) << "pipe";
+    return false;
+  }
+
+  // The parent process will only use pipe_read_fd as the read side of the
+  // pipe. It can close the write side as soon as the relauncher process has
+  // forked off. The relauncher process will only use pipe_write_fd as the
+  // write side of the pipe. In that process, the read side will be closed by
+  // base::LaunchApp because it won't be present in fd_map, and the write side
+  // will be remapped to kRelauncherSyncFD by fd_map.
+  base::ScopedFD pipe_read_fd(pipe_fds[0]);
+  base::ScopedFD pipe_write_fd(pipe_fds[1]);
+
+  // Make sure kRelauncherSyncFD is a safe value. base::LaunchProcess will
+  // preserve these three FDs in forked processes, so kRelauncherSyncFD should
+  // not conflict with them.
+  static_assert(kRelauncherSyncFD != STDIN_FILENO &&
+                kRelauncherSyncFD != STDOUT_FILENO &&
+                kRelauncherSyncFD != STDERR_FILENO,
+                "kRelauncherSyncFD must not conflict with stdio fds");
+
+  base::FileHandleMappingVector fd_map;
+  fd_map.push_back(std::make_pair(pipe_write_fd.get(), kRelauncherSyncFD));
+
+  base::LaunchOptions options;
+  options.fds_to_remap = &fd_map;
+  if (!base::LaunchProcess(relaunch_args, options).IsValid()) {
+    LOG(ERROR) << "base::LaunchProcess failed";
+    return false;
+  }
+
+  // The relauncher process is now starting up, or has started up. The
+  // original parent process continues.
+
+  pipe_write_fd.reset();  // close(pipe_fds[1]);
+
+  // Synchronize with the relauncher process.
+  char read_char;
+  int read_result = HANDLE_EINTR(read(pipe_read_fd.get(), &read_char, 1));
+  if (read_result != 1) {
+    if (read_result < 0) {
+      PLOG(ERROR) << "read";
+    } else {
+      LOG(ERROR) << "read: unexpected result " << read_result;
+    }
+    return false;
+  }
+
+  // Since a byte has been successfully read from the relauncher process, it's
+  // guaranteed to have set up its kqueue monitoring this process for exit.
+  // It's safe to exit now.
+  return true;
+}
+
+namespace {
+
+// 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() {
+  base::ScopedFD relauncher_sync_fd(kRelauncherSyncFD);
+
+  int parent_pid = getppid();
+
+  // PID 1 identifies init. launchd, that is. launchd never starts the
+  // relauncher process directly, having this parent_pid means that the parent
+  // already exited and launchd "inherited" the relauncher as its child.
+  // There's no reason to synchronize with launchd.
+  if (parent_pid == 1) {
+    LOG(ERROR) << "unexpected parent_pid";
+    return;
+  }
+
+  // Set up a kqueue to monitor the parent process for exit.
+  base::ScopedFD kq(kqueue());
+  if (!kq.is_valid()) {
+    PLOG(ERROR) << "kqueue";
+    return;
+  }
+
+  struct kevent change = { 0 };
+  EV_SET(&change, parent_pid, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, NULL);
+  if (kevent(kq.get(), &change, 1, NULL, 0, NULL) == -1) {
+    PLOG(ERROR) << "kevent (add)";
+    return;
+  }
+
+  // Write a '\0' character to the pipe.
+  if (HANDLE_EINTR(write(relauncher_sync_fd.get(), "", 1)) != 1) {
+    PLOG(ERROR) << "write";
+    return;
+  }
+
+  // Up until now, the parent process was blocked in a read waiting for the
+  // write above to complete. The parent process is now free to exit. Wait for
+  // that to happen.
+  struct kevent event;
+  int events = kevent(kq.get(), NULL, 0, &event, 1, NULL);
+  if (events != 1) {
+    if (events < 0) {
+      PLOG(ERROR) << "kevent (monitor)";
+    } else {
+      LOG(ERROR) << "kevent (monitor): unexpected result " << events;
+    }
+    return;
+  }
+
+  if (event.filter != EVFILT_PROC ||
+      event.fflags != NOTE_EXIT ||
+      event.ident != static_cast<uintptr_t>(parent_pid)) {
+    LOG(ERROR) << "kevent (monitor): unexpected event, filter " << event.filter
+               << ", fflags " << event.fflags << ", ident " << event.ident;
+    return;
+  }
+}
+
+}  // namespace
+
+namespace internal {
+
+int RelauncherMain(const content::MainFunctionParams& main_parameters) {
+  // CommandLine rearranges the order of the arguments returned by
+  // main_parameters.argv(), rendering it impossible to determine which
+  // arguments originally came before kRelauncherArgSeparator and which came
+  // after. It's crucial to distinguish between these because only those
+  // after the separator should be given to the relaunched process; it's also
+  // important to not treat the path to the relaunched process as a "loose"
+  // argument. NXArgc and NXArgv are pointers to the original argc and argv as
+  // passed to main(), so use those. Access them through _NSGetArgc and
+  // _NSGetArgv because NXArgc and NXArgv are normally only available to a
+  // main executable via crt1.o and this code will run from a dylib, and
+  // because of http://crbug.com/139902.
+  const int* argcp = _NSGetArgc();
+  if (!argcp) {
+    NOTREACHED();
+    return 1;
+  }
+  int argc = *argcp;
+
+  const char* const* const* argvp = _NSGetArgv();
+  if (!argvp) {
+    NOTREACHED();
+    return 1;
+  }
+  const char* const* argv = *argvp;
+
+  if (argc < 4 || RelauncherTypeArg() != argv[1]) {
+    LOG(ERROR) << "relauncher process invoked with unexpected arguments";
+    return 1;
+  }
+
+  RelauncherSynchronizeWithParent();
+
+  // The capacity for relaunch_args is 4 less than argc, because it
+  // won't contain the argv[0] of the relauncher process, the
+  // RelauncherTypeArg() at argv[1], kRelauncherArgSeparator, or the
+  // executable path of the process to be launched.
+  base::ScopedCFTypeRef<CFMutableArrayRef> relaunch_args(
+      CFArrayCreateMutable(NULL, argc - 4, &kCFTypeArrayCallBacks));
+  if (!relaunch_args) {
+    LOG(ERROR) << "CFArrayCreateMutable";
+    return 1;
+  }
+
+  // Figure out what to execute, what arguments to pass it, and whether to
+  // start it in the background.
+  bool background = false;
+  bool in_relaunch_args = false;
+  std::string dmg_bsd_device_name;
+  bool seen_relaunch_executable = false;
+  std::string relaunch_executable;
+  const std::string relauncher_arg_separator(kRelauncherArgSeparator);
+  const std::string relauncher_dmg_device_arg =
+      base::StringPrintf("--%s=", switches::kRelauncherProcessDMGDevice);
+  for (int argv_index = 2; argv_index < argc; ++argv_index) {
+    const std::string arg(argv[argv_index]);
+
+    // Strip any -psn_ arguments, as they apply to a specific process.
+    if (arg.compare(0, strlen(kPSNArg), kPSNArg) == 0) {
+      continue;
+    }
+
+    if (!in_relaunch_args) {
+      if (arg == relauncher_arg_separator) {
+        in_relaunch_args = true;
+      } else if (arg == kRelauncherBackgroundArg) {
+        background = true;
+      } else if (arg.compare(0,
+                             relauncher_dmg_device_arg.size(),
+                             relauncher_dmg_device_arg) == 0) {
+        dmg_bsd_device_name.assign(
+            arg.substr(relauncher_dmg_device_arg.size()));
+      }
+    } else {
+      if (!seen_relaunch_executable) {
+        // The first argument after kRelauncherBackgroundArg is the path to
+        // the executable file or .app bundle directory. The Launch Services
+        // interface wants this separate from the rest of the arguments. In
+        // the relaunched process, this path will still be visible at argv[0].
+        relaunch_executable.assign(arg);
+        seen_relaunch_executable = true;
+      } else {
+        base::ScopedCFTypeRef<CFStringRef> arg_cf(
+            base::SysUTF8ToCFStringRef(arg));
+        if (!arg_cf) {
+          LOG(ERROR) << "base::SysUTF8ToCFStringRef failed for " << arg;
+          return 1;
+        }
+        CFArrayAppendValue(relaunch_args, arg_cf);
+      }
+    }
+  }
+
+  if (!seen_relaunch_executable) {
+    LOG(ERROR) << "nothing to relaunch";
+    return 1;
+  }
+
+  FSRef app_fsref;
+  if (!base::mac::FSRefFromPath(relaunch_executable, &app_fsref)) {
+    LOG(ERROR) << "base::mac::FSRefFromPath failed for " << relaunch_executable;
+    return 1;
+  }
+
+  LSApplicationParameters ls_parameters = {
+    0,  // version
+    kLSLaunchDefaults | kLSLaunchAndDisplayErrors | kLSLaunchNewInstance |
+        (background ? kLSLaunchDontSwitch : 0),
+    &app_fsref,
+    NULL,  // asyncLaunchRefCon
+    NULL,  // environment
+    relaunch_args,
+    NULL   // initialEvent
+  };
+
+  OSStatus status = LSOpenApplication(&ls_parameters, NULL);
+  if (status != noErr) {
+    OSSTATUS_LOG(ERROR, status) << "LSOpenApplication";
+    return 1;
+  }
+
+  // The application should have relaunched (or is in the process of
+  // relaunching). From this point on, only clean-up tasks should occur, and
+  // failures are tolerable.
+
+  if (!dmg_bsd_device_name.empty()) {
+    EjectAndTrashDiskImage(dmg_bsd_device_name);
+  }
+
+  return 0;
+}
+
+}  // namespace internal
+
+}  // namespace mac_relauncher

chromium_src/chrome/browser/mac/relauncher.h

@@ -0,0 +1,77 @@
+// Copyright (c) 2011 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef CHROME_BROWSER_MAC_RELAUNCHER_H_
+#define CHROME_BROWSER_MAC_RELAUNCHER_H_
+
+// mac_relauncher implements main browser application relaunches on the Mac.
+// 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.
+//
+// mac_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 mac_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);
+
+namespace internal {
+
+// The entry point from ChromeMain into the relauncher process. This is not a
+// user API. Don't call it if your name isn't ChromeMain.
+int RelauncherMain(const content::MainFunctionParams& main_parameters);
+
+}  // namespace internal
+
+}  // namespace mac_relauncher
+
+#endif  // CHROME_BROWSER_MAC_RELAUNCHER_H_

filenames.gypi

@@ -420,6 +420,8 @@
       'chromium_src/chrome/browser/extensions/global_shortcut_listener_x11.h',
       'chromium_src/chrome/browser/extensions/global_shortcut_listener_win.cc',
       'chromium_src/chrome/browser/extensions/global_shortcut_listener_win.h',
+      'chromium_src/chrome/browser/mac/relauncher.cc',
+      'chromium_src/chrome/browser/mac/relauncher.h',
       'chromium_src/chrome/browser/media/desktop_media_list.h',
       'chromium_src/chrome/browser/media/desktop_media_list_observer.h',
       'chromium_src/chrome/browser/media/native_desktop_media_list.cc',