chrome/browser/chrome_browser_main_posix.cc

   1 // Copyright (c) 2012 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 #include "chrome/browser/chrome_browser_main_posix.h"
   6
   7 #include <errno.h>
   8 #include <limits.h>
   9 #include <pthread.h>
  10 #include <signal.h>
  11 #include <sys/resource.h>
  12 #include <unistd.h>
  13
  14 #include <string>
  15
  16 #include "base/bind.h"
  17 #include "base/command_line.h"
  18 #include "base/logging.h"
  19 #include "base/posix/eintr_wrapper.h"
  20 #include "base/strings/string_number_conversions.h"
  21 #include "chrome/browser/chrome_notification_types.h"
  22 #include "chrome/browser/lifetime/application_lifetime.h"
  23 #include "chrome/browser/sessions/session_restore.h"
  24 #include "chrome/common/chrome_switches.h"
  25 #include "content/public/browser/browser_thread.h"
  26
  27 using content::BrowserThread;
  28
  29 namespace {
  30
  31 // See comment in |PreEarlyInitialization()|, where sigaction is called.
  32 void SIGCHLDHandler(int signal) {
  33 }
  34
  35 // The OSX fork() implementation can crash in the child process before
  36 // fork() returns.  In that case, the shutdown pipe will still be
  37 // shared with the parent process.  To prevent child crashes from
  38 // causing parent shutdowns, |g_pipe_pid| is the pid for the process
  39 // which registered |g_shutdown_pipe_write_fd|.
  40 // See <http://crbug.com/175341>.
  41 pid_t g_pipe_pid = -1;
  42 int g_shutdown_pipe_write_fd = -1;
  43 int g_shutdown_pipe_read_fd = -1;
  44
  45 // Common code between SIG{HUP, INT, TERM}Handler.
  46 void GracefulShutdownHandler(int signal) {
  47   // Reinstall the default handler.  We had one shot at graceful shutdown.
  48   struct sigaction action;
  49   memset(&action, 0, sizeof(action));
  50   action.sa_handler = SIG_DFL;
  51   RAW_CHECK(sigaction(signal, &action, NULL) == 0);
  52
  53   RAW_CHECK(g_pipe_pid == getpid());
  54   RAW_CHECK(g_shutdown_pipe_write_fd != -1);
  55   RAW_CHECK(g_shutdown_pipe_read_fd != -1);
  56   size_t bytes_written = 0;
  57   do {
  58     int rv = HANDLE_EINTR(
  59         write(g_shutdown_pipe_write_fd,
  60               reinterpret_cast<const char*>(&signal) + bytes_written,
  61               sizeof(signal) - bytes_written));
  62     RAW_CHECK(rv >= 0);
  63     bytes_written += rv;
  64   } while (bytes_written < sizeof(signal));
  65 }
  66
  67 // See comment in |PostMainMessageLoopStart()|, where sigaction is called.
  68 void SIGHUPHandler(int signal) {
  69   RAW_CHECK(signal == SIGHUP);
  70   GracefulShutdownHandler(signal);
  71 }
  72
  73 // See comment in |PostMainMessageLoopStart()|, where sigaction is called.
  74 void SIGINTHandler(int signal) {
  75   RAW_CHECK(signal == SIGINT);
  76   GracefulShutdownHandler(signal);
  77 }
  78
  79 // See comment in |PostMainMessageLoopStart()|, where sigaction is called.
  80 void SIGTERMHandler(int signal) {
  81   RAW_CHECK(signal == SIGTERM);
  82   GracefulShutdownHandler(signal);
  83 }
  84
  85 // ExitHandler takes care of servicing an exit (from a signal) at the
  86 // appropriate time. Specifically if we get an exit and have not finished
  87 // session restore we delay the exit. To do otherwise means we're exiting part
  88 // way through startup which causes all sorts of problems.
  89 class ExitHandler {
  90  public:
  91   // Invokes exit when appropriate.
  92   static void ExitWhenPossibleOnUIThread();
  93
  94  private:
  95   ExitHandler();
  96   ~ExitHandler();
  97
  98   // Called when a session restore has finished.
  99   void OnSessionRestoreDone(int num_tabs_restored);
 100
 101   // Does the appropriate call to Exit.
 102   static void Exit();
 103
 104   // Points to the on-session-restored callback that was registered with
 105   // SessionRestore's callback list. When objects of this class are destroyed,
 106   // the subscription object's destructor will automatically unregister the
 107   // callback in SessionRestore, so that the callback list does not contain any
 108   // obsolete callbacks.
 109   SessionRestore::CallbackSubscription
 110       on_session_restored_callback_subscription_;
 111
 112   DISALLOW_COPY_AND_ASSIGN(ExitHandler);
 113 };
 114
 115 // static
 116 void ExitHandler::ExitWhenPossibleOnUIThread() {
 117   DCHECK_CURRENTLY_ON(content::BrowserThread::UI);
 118   if (SessionRestore::IsRestoringSynchronously()) {
 119     // ExitHandler takes care of deleting itself.
 120     new ExitHandler();
 121   } else {
 122     Exit();
 123   }
 124 }
 125
 126 ExitHandler::ExitHandler() {
 127   on_session_restored_callback_subscription_ =
 128       SessionRestore::RegisterOnSessionRestoredCallback(
 129           base::Bind(&ExitHandler::OnSessionRestoreDone,
 130                      base::Unretained(this)));
 131 }
 132
 133 ExitHandler::~ExitHandler() {
 134 }
 135
 136 void ExitHandler::OnSessionRestoreDone(int /* num_tabs */) {
 137   if (!SessionRestore::IsRestoringSynchronously()) {
 138     // At this point the message loop may not be running (meaning we haven't
 139     // gotten through browser startup, but are close). Post the task to at which
 140     // point the message loop is running.
 141     BrowserThread::PostTask(BrowserThread::UI, FROM_HERE,
 142                             base::Bind(&ExitHandler::Exit));
 143     delete this;
 144   }
 145 }
 146
 147 // static
 148 void ExitHandler::Exit() {
 149 #if defined(OS_CHROMEOS)
 150   // On ChromeOS, exiting on signal should be always clean.
 151   chrome::ExitCleanly();
 152 #else
 153   chrome::AttemptExit();
 154 #endif
 155 }
 156
 157 class ShutdownDetector : public base::PlatformThread::Delegate {
 158  public:
 159   explicit ShutdownDetector(int shutdown_fd);
 160
 161   void ThreadMain() override;
 162
 163  private:
 164   const int shutdown_fd_;
 165
 166   DISALLOW_COPY_AND_ASSIGN(ShutdownDetector);
 167 };
 168
 169 ShutdownDetector::ShutdownDetector(int shutdown_fd)
 170     : shutdown_fd_(shutdown_fd) {
 171   CHECK_NE(shutdown_fd_, -1);
 172 }
 173
 174 // These functions are used to help us diagnose crash dumps that happen
 175 // during the shutdown process.
 176 NOINLINE void ShutdownFDReadError() {
 177   // Ensure function isn't optimized away.
 178   asm("");
 179   sleep(UINT_MAX);
 180 }
 181
 182 NOINLINE void ShutdownFDClosedError() {
 183   // Ensure function isn't optimized away.
 184   asm("");
 185   sleep(UINT_MAX);
 186 }
 187
 188 NOINLINE void ExitPosted() {
 189   // Ensure function isn't optimized away.
 190   asm("");
 191   sleep(UINT_MAX);
 192 }
 193
 194 void ShutdownDetector::ThreadMain() {
 195   base::PlatformThread::SetName("CrShutdownDetector");
 196
 197   int signal;
 198   size_t bytes_read = 0;
 199   ssize_t ret;
 200   do {
 201     ret = HANDLE_EINTR(
 202         read(shutdown_fd_,
 203              reinterpret_cast<char*>(&signal) + bytes_read,
 204              sizeof(signal) - bytes_read));
 205     if (ret < 0) {
 206       NOTREACHED() << "Unexpected error: " << strerror(errno);
 207       ShutdownFDReadError();
 208       break;
 209     } else if (ret == 0) {
 210       NOTREACHED() << "Unexpected closure of shutdown pipe.";
 211       ShutdownFDClosedError();
 212       break;
 213     }
 214     bytes_read += ret;
 215   } while (bytes_read < sizeof(signal));
 216   VLOG(1) << "Handling shutdown for signal " << signal << ".";
 217   base::Closure task = base::Bind(&ExitHandler::ExitWhenPossibleOnUIThread);
 218
 219   if (!BrowserThread::PostTask(BrowserThread::UI, FROM_HERE, task)) {
 220     // Without a UI thread to post the exit task to, there aren't many
 221     // options.  Raise the signal again.  The default handler will pick it up
 222     // and cause an ungraceful exit.
 223     RAW_LOG(WARNING, "No UI thread, exiting ungracefully.");
 224     kill(getpid(), signal);
 225
 226     // The signal may be handled on another thread.  Give that a chance to
 227     // happen.
 228     sleep(3);
 229
 230     // We really should be dead by now.  For whatever reason, we're not. Exit
 231     // immediately, with the exit status set to the signal number with bit 8
 232     // set.  On the systems that we care about, this exit status is what is
 233     // normally used to indicate an exit by this signal's default handler.
 234     // This mechanism isn't a de jure standard, but even in the worst case, it
 235     // should at least result in an immediate exit.
 236     RAW_LOG(WARNING, "Still here, exiting really ungracefully.");
 237     _exit(signal | (1 << 7));
 238   }
 239   ExitPosted();
 240 }
 241
 242 }  // namespace
 243
 244 // ChromeBrowserMainPartsPosix -------------------------------------------------
 245
 246 ChromeBrowserMainPartsPosix::ChromeBrowserMainPartsPosix(
 247     const content::MainFunctionParams& parameters)
 248     : ChromeBrowserMainParts(parameters) {
 249 }
 250
 251 void ChromeBrowserMainPartsPosix::PreEarlyInitialization() {
 252   ChromeBrowserMainParts::PreEarlyInitialization();
 253
 254   // We need to accept SIGCHLD, even though our handler is a no-op because
 255   // otherwise we cannot wait on children. (According to POSIX 2001.)
 256   struct sigaction action;
 257   memset(&action, 0, sizeof(action));
 258   action.sa_handler = SIGCHLDHandler;
 259   CHECK(sigaction(SIGCHLD, &action, NULL) == 0);
 260 }
 261
 262 void ChromeBrowserMainPartsPosix::PostMainMessageLoopStart() {
 263   ChromeBrowserMainParts::PostMainMessageLoopStart();
 264
 265   int pipefd[2];
 266   int ret = pipe(pipefd);
 267   if (ret < 0) {
 268     PLOG(DFATAL) << "Failed to create pipe";
 269   } else {
 270     g_pipe_pid = getpid();
 271     g_shutdown_pipe_read_fd = pipefd[0];
 272     g_shutdown_pipe_write_fd = pipefd[1];
 273 #if !defined(ADDRESS_SANITIZER) && !defined(KEEP_SHADOW_STACKS)
 274     const size_t kShutdownDetectorThreadStackSize = PTHREAD_STACK_MIN * 2;
 275 #else
 276     // ASan instrumentation and -finstrument-functions (used for keeping the
 277     // shadow stacks) bloat the stack frames, so we need to increase the stack
 278     // size to avoid hitting the guard page.
 279     const size_t kShutdownDetectorThreadStackSize = PTHREAD_STACK_MIN * 4;
 280 #endif
 281     // TODO(viettrungluu,willchan): crbug.com/29675 - This currently leaks, so
 282     // if you change this, you'll probably need to change the suppression.
 283     if (!base::PlatformThread::CreateNonJoinable(
 284             kShutdownDetectorThreadStackSize,
 285             new ShutdownDetector(g_shutdown_pipe_read_fd))) {
 286       LOG(DFATAL) << "Failed to create shutdown detector task.";
 287     }
 288   }
 289   // Setup signal handlers for shutdown AFTER shutdown pipe is setup because
 290   // it may be called right away after handler is set.
 291
 292   // If adding to this list of signal handlers, note the new signal probably
 293   // needs to be reset in child processes. See
 294   // base/process_util_posix.cc:LaunchProcess.
 295
 296   // We need to handle SIGTERM, because that is how many POSIX-based distros ask
 297   // processes to quit gracefully at shutdown time.
 298   struct sigaction action;
 299   memset(&action, 0, sizeof(action));
 300   action.sa_handler = SIGTERMHandler;
 301   CHECK(sigaction(SIGTERM, &action, NULL) == 0);
 302   // Also handle SIGINT - when the user terminates the browser via Ctrl+C. If
 303   // the browser process is being debugged, GDB will catch the SIGINT first.
 304   action.sa_handler = SIGINTHandler;
 305   CHECK(sigaction(SIGINT, &action, NULL) == 0);
 306   // And SIGHUP, for when the terminal disappears. On shutdown, many Linux
 307   // distros send SIGHUP, SIGTERM, and then SIGKILL.
 308   action.sa_handler = SIGHUPHandler;
 309   CHECK(sigaction(SIGHUP, &action, NULL) == 0);
 310 }
 311
 312 void ChromeBrowserMainPartsPosix::ShowMissingLocaleMessageBox() {
 313 #if defined(OS_CHROMEOS)
 314   NOTREACHED();  // Should not ever happen on ChromeOS.
 315 #elif defined(OS_MACOSX)
 316   // Not called on Mac because we load the locale files differently.
 317   NOTREACHED();
 318 #elif defined(USE_AURA)
 319   // TODO(port): We may want a views based message dialog here eventually, but
 320   // for now, crash.
 321   NOTREACHED();
 322 #else
 323 #error "Need MessageBox implementation."
 324 #endif
 325 }