chrome/common/service_process_util_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/common/service_process_util_posix.h"
   6
   7 #include "base/basictypes.h"
   8 #include "base/bind.h"
   9 #include "base/message_loop/message_loop_proxy.h"
  10 #include "base/posix/eintr_wrapper.h"
  11 #include "base/synchronization/waitable_event.h"
  12 #include "chrome/common/multi_process_lock.h"
  13
  14 namespace {
  15 int g_signal_socket = -1;
  16 }
  17
  18 // Attempts to take a lock named |name|. If |waiting| is true then this will
  19 // make multiple attempts to acquire the lock.
  20 // Caller is responsible for ownership of the MultiProcessLock.
  21 MultiProcessLock* TakeNamedLock(const std::string& name, bool waiting) {
  22   scoped_ptr<MultiProcessLock> lock(MultiProcessLock::Create(name));
  23   if (lock == NULL) return NULL;
  24   bool got_lock = false;
  25   for (int i = 0; i < 10; ++i) {
  26     if (lock->TryLock()) {
  27       got_lock = true;
  28       break;
  29     }
  30     if (!waiting) break;
  31     base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(100 * i));
  32   }
  33   if (!got_lock) {
  34     lock.reset();
  35   }
  36   return lock.release();
  37 }
  38
  39 ServiceProcessTerminateMonitor::ServiceProcessTerminateMonitor(
  40     const base::Closure& terminate_task)
  41     : terminate_task_(terminate_task) {
  42 }
  43
  44 ServiceProcessTerminateMonitor::~ServiceProcessTerminateMonitor() {
  45 }
  46
  47 void ServiceProcessTerminateMonitor::OnFileCanReadWithoutBlocking(int fd) {
  48   if (!terminate_task_.is_null()) {
  49     int buffer;
  50     int length = read(fd, &buffer, sizeof(buffer));
  51     if ((length == sizeof(buffer)) && (buffer == kTerminateMessage)) {
  52       terminate_task_.Run();
  53       terminate_task_.Reset();
  54     } else if (length > 0) {
  55       DLOG(ERROR) << "Unexpected read: " << buffer;
  56     } else if (length == 0) {
  57       DLOG(ERROR) << "Unexpected fd close";
  58     } else if (length < 0) {
  59       DPLOG(ERROR) << "read";
  60     }
  61   }
  62 }
  63
  64 void ServiceProcessTerminateMonitor::OnFileCanWriteWithoutBlocking(int fd) {
  65   NOTIMPLEMENTED();
  66 }
  67
  68 // "Forced" Shutdowns on POSIX are done via signals. The magic signal for
  69 // a shutdown is SIGTERM. "write" is a signal safe function. PLOG(ERROR) is
  70 // not, but we don't ever expect it to be called.
  71 static void SigTermHandler(int sig, siginfo_t* info, void* uap) {
  72   // TODO(dmaclach): add security here to make sure that we are being shut
  73   //                 down by an appropriate process.
  74   int message = ServiceProcessTerminateMonitor::kTerminateMessage;
  75   if (write(g_signal_socket, &message, sizeof(message)) < 0) {
  76     DPLOG(ERROR) << "write";
  77   }
  78 }
  79
  80 ServiceProcessState::StateData::StateData() : set_action_(false) {
  81   memset(sockets_, -1, sizeof(sockets_));
  82   memset(&old_action_, 0, sizeof(old_action_));
  83 }
  84
  85 void ServiceProcessState::StateData::SignalReady(base::WaitableEvent* signal,
  86                                                  bool* success) {
  87   DCHECK_EQ(g_signal_socket, -1);
  88   DCHECK(!signal->IsSignaled());
  89   *success = base::MessageLoopForIO::current()->WatchFileDescriptor(
  90       sockets_[0],
  91       true,
  92       base::MessageLoopForIO::WATCH_READ,
  93       &watcher_,
  94       terminate_monitor_.get());
  95   if (!*success) {
  96     DLOG(ERROR) << "WatchFileDescriptor";
  97     signal->Signal();
  98     return;
  99   }
 100   g_signal_socket = sockets_[1];
 101
 102   // Set up signal handler for SIGTERM.
 103   struct sigaction action;
 104   memset(&action, 0, sizeof(action));
 105   action.sa_sigaction = SigTermHandler;
 106   sigemptyset(&action.sa_mask);
 107   action.sa_flags = SA_SIGINFO;
 108   *success = sigaction(SIGTERM, &action, &old_action_) == 0;
 109   if (!*success) {
 110     DPLOG(ERROR) << "sigaction";
 111     signal->Signal();
 112     return;
 113   }
 114
 115   // If the old_action is not default, somebody else has installed a
 116   // a competing handler. Our handler is going to override it so it
 117   // won't be called. If this occurs it needs to be fixed.
 118   DCHECK_EQ(old_action_.sa_handler, SIG_DFL);
 119   set_action_ = true;
 120
 121 #if defined(OS_MACOSX)
 122   *success = WatchExecutable();
 123   if (!*success) {
 124     DLOG(ERROR) << "WatchExecutable";
 125     signal->Signal();
 126     return;
 127   }
 128 #elif defined(OS_POSIX)
 129   initializing_lock_.reset();
 130 #endif  // OS_POSIX
 131   signal->Signal();
 132 }
 133
 134 ServiceProcessState::StateData::~StateData() {
 135   if (sockets_[0] != -1) {
 136     if (HANDLE_EINTR(close(sockets_[0]))) {
 137       DPLOG(ERROR) << "close";
 138     }
 139   }
 140   if (sockets_[1] != -1) {
 141     if (HANDLE_EINTR(close(sockets_[1]))) {
 142       DPLOG(ERROR) << "close";
 143     }
 144   }
 145   if (set_action_) {
 146     if (sigaction(SIGTERM, &old_action_, NULL) < 0) {
 147       DPLOG(ERROR) << "sigaction";
 148     }
 149   }
 150   g_signal_socket = -1;
 151 }
 152
 153 void ServiceProcessState::CreateState() {
 154   DCHECK(!state_);
 155   state_ = new StateData;
 156
 157   // Explicitly adding a reference here (and removing it in TearDownState)
 158   // because StateData is refcounted on Mac and Linux so that methods can
 159   // be called on other threads.
 160   // It is not refcounted on Windows at this time.
 161   state_->AddRef();
 162 }
 163
 164 bool ServiceProcessState::SignalReady(
 165     base::MessageLoopProxy* message_loop_proxy,
 166     const base::Closure& terminate_task) {
 167   DCHECK(state_);
 168
 169 #if defined(OS_POSIX) && !defined(OS_MACOSX)
 170   state_->running_lock_.reset(TakeServiceRunningLock(true));
 171   if (state_->running_lock_.get() == NULL) {
 172     return false;
 173   }
 174 #endif
 175   state_->terminate_monitor_.reset(
 176       new ServiceProcessTerminateMonitor(terminate_task));
 177   if (pipe(state_->sockets_) < 0) {
 178     DPLOG(ERROR) << "pipe";
 179     return false;
 180   }
 181   base::WaitableEvent signal_ready(true, false);
 182   bool success = false;
 183
 184   message_loop_proxy->PostTask(FROM_HERE,
 185       base::Bind(&ServiceProcessState::StateData::SignalReady,
 186                  state_,
 187                  &signal_ready,
 188                  &success));
 189   signal_ready.Wait();
 190   return success;
 191 }
 192
 193 void ServiceProcessState::TearDownState() {
 194   if (state_) {
 195     state_->Release();
 196     state_ = NULL;
 197   }
 198 }