Split out process killing functions from base/process_util.h into base/process/kill.h.

base/process/kill_posix.cc

+// Copyright (c) 2013 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 "base/process/kill.h"
+
+#include <signal.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "base/file_util.h"
+#include "base/logging.h"
+#include "base/posix/eintr_wrapper.h"
+#include "base/process/process_iterator.h"
+#include "base/process_util.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/third_party/dynamic_annotations/dynamic_annotations.h"
+#include "base/threading/platform_thread.h"
+
+namespace base {
+
+namespace {
+
+int WaitpidWithTimeout(ProcessHandle handle,
+                       int64 wait_milliseconds,
+                       bool* success) {
+  // This POSIX version of this function only guarantees that we wait no less
+  // than |wait_milliseconds| for the process to exit.  The child process may
+  // exit sometime before the timeout has ended but we may still block for up
+  // to 256 milliseconds after the fact.
+  //
+  // waitpid() has no direct support on POSIX for specifying a timeout, you can
+  // either ask it to block indefinitely or return immediately (WNOHANG).
+  // When a child process terminates a SIGCHLD signal is sent to the parent.
+  // Catching this signal would involve installing a signal handler which may
+  // affect other parts of the application and would be difficult to debug.
+  //
+  // Our strategy is to call waitpid() once up front to check if the process
+  // has already exited, otherwise to loop for wait_milliseconds, sleeping for
+  // at most 256 milliseconds each time using usleep() and then calling
+  // waitpid().  The amount of time we sleep starts out at 1 milliseconds, and
+  // we double it every 4 sleep cycles.
+  //
+  // usleep() is speced to exit if a signal is received for which a handler
+  // has been installed.  This means that when a SIGCHLD is sent, it will exit
+  // depending on behavior external to this function.
+  //
+  // This function is used primarily for unit tests, if we want to use it in
+  // the application itself it would probably be best to examine other routes.
+  int status = -1;
+  pid_t ret_pid = HANDLE_EINTR(waitpid(handle, &status, WNOHANG));
+  static const int64 kMaxSleepInMicroseconds = 1 << 18;  // ~256 milliseconds.
+  int64 max_sleep_time_usecs = 1 << 10;  // ~1 milliseconds.
+  int64 double_sleep_time = 0;
+
+  // If the process hasn't exited yet, then sleep and try again.
+  TimeTicks wakeup_time = TimeTicks::Now() +
+      TimeDelta::FromMilliseconds(wait_milliseconds);
+  while (ret_pid == 0) {
+    TimeTicks now = TimeTicks::Now();
+    if (now > wakeup_time)
+      break;
+    // Guaranteed to be non-negative!
+    int64 sleep_time_usecs = (wakeup_time - now).InMicroseconds();
+    // Sleep for a bit while we wait for the process to finish.
+    if (sleep_time_usecs > max_sleep_time_usecs)
+      sleep_time_usecs = max_sleep_time_usecs;
+
+    // usleep() will return 0 and set errno to EINTR on receipt of a signal
+    // such as SIGCHLD.
+    usleep(sleep_time_usecs);
+    ret_pid = HANDLE_EINTR(waitpid(handle, &status, WNOHANG));
+
+    if ((max_sleep_time_usecs < kMaxSleepInMicroseconds) &&
+        (double_sleep_time++ % 4 == 0)) {
+      max_sleep_time_usecs *= 2;
+    }
+  }
+
+  if (success)
+    *success = (ret_pid != -1);
+
+  return status;
+}
+
+TerminationStatus GetTerminationStatusImpl(ProcessHandle handle,
+                                           bool can_block,
+                                           int* exit_code) {
+  int status = 0;
+  const pid_t result = HANDLE_EINTR(waitpid(handle, &status,
+                                            can_block ? 0 : WNOHANG));
+  if (result == -1) {
+    DPLOG(ERROR) << "waitpid(" << handle << ")";
+    if (exit_code)
+      *exit_code = 0;
+    return TERMINATION_STATUS_NORMAL_TERMINATION;
+  } else if (result == 0) {
+    // the child hasn't exited yet.
+    if (exit_code)
+      *exit_code = 0;
+    return TERMINATION_STATUS_STILL_RUNNING;
+  }
+
+  if (exit_code)
+    *exit_code = status;
+
+  if (WIFSIGNALED(status)) {
+    switch (WTERMSIG(status)) {
+      case SIGABRT:
+      case SIGBUS:
+      case SIGFPE:
+      case SIGILL:
+      case SIGSEGV:
+        return TERMINATION_STATUS_PROCESS_CRASHED;
+      case SIGINT:
+      case SIGKILL:
+      case SIGTERM:
+        return TERMINATION_STATUS_PROCESS_WAS_KILLED;
+      default:
+        break;
+    }
+  }
+
+  if (WIFEXITED(status) && WEXITSTATUS(status) != 0)
+    return TERMINATION_STATUS_ABNORMAL_TERMINATION;
+
+  return TERMINATION_STATUS_NORMAL_TERMINATION;
+}
+
+}  // namespace
+
+// Attempts to kill the process identified by the given process
+// entry structure.  Ignores specified exit_code; posix can't force that.
+// Returns true if this is successful, false otherwise.
+bool KillProcess(ProcessHandle process_id, int exit_code, bool wait) {
+  DCHECK_GT(process_id, 1) << " tried to kill invalid process_id";
+  if (process_id <= 1)
+    return false;
+  bool result = kill(process_id, SIGTERM) == 0;
+  if (result && wait) {
+    int tries = 60;
+
+    if (RunningOnValgrind()) {
+      // Wait for some extra time when running under Valgrind since the child
+      // processes may take some time doing leak checking.
+      tries *= 2;
+    }
+
+    unsigned sleep_ms = 4;
+
+    // The process may not end immediately due to pending I/O
+    bool exited = false;
+    while (tries-- > 0) {
+      pid_t pid = HANDLE_EINTR(waitpid(process_id, NULL, WNOHANG));
+      if (pid == process_id) {
+        exited = true;
+        break;
+      }
+      if (pid == -1) {
+        if (errno == ECHILD) {
+          // The wait may fail with ECHILD if another process also waited for
+          // the same pid, causing the process state to get cleaned up.
+          exited = true;
+          break;
+        }
+        DPLOG(ERROR) << "Error waiting for process " << process_id;
+      }
+
+      usleep(sleep_ms * 1000);
+      const unsigned kMaxSleepMs = 1000;
+      if (sleep_ms < kMaxSleepMs)
+        sleep_ms *= 2;
+    }
+
+    // If we're waiting and the child hasn't died by now, force it
+    // with a SIGKILL.
+    if (!exited)
+      result = kill(process_id, SIGKILL) == 0;
+  }
+
+  if (!result)
+    DPLOG(ERROR) << "Unable to terminate process " << process_id;
+
+  return result;
+}
+
+bool KillProcessGroup(ProcessHandle process_group_id) {
+  bool result = kill(-1 * process_group_id, SIGKILL) == 0;
+  if (!result)
+    DPLOG(ERROR) << "Unable to terminate process group " << process_group_id;
+  return result;
+}
+
+TerminationStatus GetTerminationStatus(ProcessHandle handle, int* exit_code) {
+  return GetTerminationStatusImpl(handle, false /* can_block */, exit_code);
+}
+
+TerminationStatus WaitForTerminationStatus(ProcessHandle handle,
+                                           int* exit_code) {
+  return GetTerminationStatusImpl(handle, true /* can_block */, exit_code);
+}
+
+bool WaitForExitCode(ProcessHandle handle, int* exit_code) {
+  int status;
+  if (HANDLE_EINTR(waitpid(handle, &status, 0)) == -1) {
+    NOTREACHED();
+    return false;
+  }
+
+  if (WIFEXITED(status)) {
+    *exit_code = WEXITSTATUS(status);
+    return true;
+  }
+
+  // If it didn't exit cleanly, it must have been signaled.
+  DCHECK(WIFSIGNALED(status));
+  return false;
+}
+
+bool WaitForExitCodeWithTimeout(ProcessHandle handle,
+                                int* exit_code,
+                                base::TimeDelta timeout) {
+  bool waitpid_success = false;
+  int status = WaitpidWithTimeout(handle, timeout.InMilliseconds(),
+                                  &waitpid_success);
+  if (status == -1)
+    return false;
+  if (!waitpid_success)
+    return false;
+  if (WIFSIGNALED(status)) {
+    *exit_code = -1;
+    return true;
+  }
+  if (WIFEXITED(status)) {
+    *exit_code = WEXITSTATUS(status);
+    return true;
+  }
+  return false;
+}
+
+bool WaitForProcessesToExit(const FilePath::StringType& executable_name,
+                            base::TimeDelta wait,
+                            const ProcessFilter* filter) {
+  bool result = false;
+
+  // TODO(port): This is inefficient, but works if there are multiple procs.
+  // TODO(port): use waitpid to avoid leaving zombies around
+
+  base::TimeTicks end_time = base::TimeTicks::Now() + wait;
+  do {
+    NamedProcessIterator iter(executable_name, filter);
+    if (!iter.NextProcessEntry()) {
+      result = true;
+      break;
+    }
+    base::PlatformThread::Sleep(base::TimeDelta::FromMilliseconds(100));
+  } while ((end_time - base::TimeTicks::Now()) > base::TimeDelta());
+
+  return result;
+}
+
+#if defined(OS_MACOSX)
+// Using kqueue on Mac so that we can wait on non-child processes.
+// We can't use kqueues on child processes because we need to reap
+// our own children using wait.
+static bool WaitForSingleNonChildProcess(ProcessHandle handle,
+                                         base::TimeDelta wait) {
+  DCHECK_GT(handle, 0);
+  DCHECK(wait.InMilliseconds() == base::kNoTimeout || wait > base::TimeDelta());
+
+  int kq = kqueue();
+  if (kq == -1) {
+    DPLOG(ERROR) << "kqueue";
+    return false;
+  }
+  file_util::ScopedFD kq_closer(&kq);
+
+  struct kevent change = {0};
+  EV_SET(&change, handle, EVFILT_PROC, EV_ADD, NOTE_EXIT, 0, NULL);
+  int result = HANDLE_EINTR(kevent(kq, &change, 1, NULL, 0, NULL));
+  if (result == -1) {
+    if (errno == ESRCH) {
+      // If the process wasn't found, it must be dead.
+      return true;
+    }
+
+    DPLOG(ERROR) << "kevent (setup " << handle << ")";
+    return false;
+  }
+
+  // Keep track of the elapsed time to be able to restart kevent if it's
+  // interrupted.
+  bool wait_forever = wait.InMilliseconds() == base::kNoTimeout;
+  base::TimeDelta remaining_delta;
+  base::TimeTicks deadline;
+  if (!wait_forever) {
+    remaining_delta = wait;
+    deadline = base::TimeTicks::Now() + remaining_delta;
+  }
+
+  result = -1;
+  struct kevent event = {0};
+
+  while (wait_forever || remaining_delta > base::TimeDelta()) {
+    struct timespec remaining_timespec;
+    struct timespec* remaining_timespec_ptr;
+    if (wait_forever) {
+      remaining_timespec_ptr = NULL;
+    } else {
+      remaining_timespec = remaining_delta.ToTimeSpec();
+      remaining_timespec_ptr = &remaining_timespec;
+    }
+
+    result = kevent(kq, NULL, 0, &event, 1, remaining_timespec_ptr);
+
+    if (result == -1 && errno == EINTR) {
+      if (!wait_forever) {
+        remaining_delta = deadline - base::TimeTicks::Now();
+      }
+      result = 0;
+    } else {
+      break;
+    }
+  }
+
+  if (result < 0) {
+    DPLOG(ERROR) << "kevent (wait " << handle << ")";
+    return false;
+  } else if (result > 1) {
+    DLOG(ERROR) << "kevent (wait " << handle << "): unexpected result "
+                << result;
+    return false;
+  } else if (result == 0) {
+    // Timed out.
+    return false;
+  }
+
+  DCHECK_EQ(result, 1);
+
+  if (event.filter != EVFILT_PROC ||
+      (event.fflags & NOTE_EXIT) == 0 ||
+      event.ident != static_cast<uintptr_t>(handle)) {
+    DLOG(ERROR) << "kevent (wait " << handle
+                << "): unexpected event: filter=" << event.filter
+                << ", fflags=" << event.fflags
+                << ", ident=" << event.ident;
+    return false;
+  }
+
+  return true;
+}
+#endif  // OS_MACOSX
+
+bool WaitForSingleProcess(ProcessHandle handle, base::TimeDelta wait) {
+  ProcessHandle parent_pid = GetParentProcessId(handle);
+  ProcessHandle our_pid = Process::Current().handle();
+  if (parent_pid != our_pid) {
+#if defined(OS_MACOSX)
+    // On Mac we can wait on non child processes.
+    return WaitForSingleNonChildProcess(handle, wait);
+#else
+    // Currently on Linux we can't handle non child processes.
+    NOTIMPLEMENTED();
+#endif  // OS_MACOSX
+  }
+
+  bool waitpid_success;
+  int status = -1;
+  if (wait.InMilliseconds() == base::kNoTimeout) {
+    waitpid_success = (HANDLE_EINTR(waitpid(handle, &status, 0)) != -1);
+  } else {
+    status = WaitpidWithTimeout(
+        handle, wait.InMilliseconds(), &waitpid_success);
+  }
+
+  if (status != -1) {
+    DCHECK(waitpid_success);
+    return WIFEXITED(status);
+  } else {
+    return false;
+  }
+}
+
+bool CleanupProcesses(const FilePath::StringType& executable_name,
+                      base::TimeDelta wait,
+                      int exit_code,
+                      const ProcessFilter* filter) {
+  bool exited_cleanly = WaitForProcessesToExit(executable_name, wait, filter);
+  if (!exited_cleanly)
+    KillProcesses(executable_name, exit_code, filter);
+  return exited_cleanly;
+}
+
+#if !defined(OS_MACOSX)
+
+namespace {
+
+// Return true if the given child is dead. This will also reap the process.
+// Doesn't block.
+static bool IsChildDead(pid_t child) {
+  const pid_t result = HANDLE_EINTR(waitpid(child, NULL, WNOHANG));
+  if (result == -1) {
+    DPLOG(ERROR) << "waitpid(" << child << ")";
+    NOTREACHED();
+  } else if (result > 0) {
+    // The child has died.
+    return true;
+  }
+
+  return false;
+}
+
+// A thread class which waits for the given child to exit and reaps it.
+// If the child doesn't exit within a couple of seconds, kill it.
+class BackgroundReaper : public PlatformThread::Delegate {
+ public:
+  BackgroundReaper(pid_t child, unsigned timeout)
+      : child_(child),
+        timeout_(timeout) {
+  }
+
+  // Overridden from PlatformThread::Delegate:
+  virtual void ThreadMain() OVERRIDE {
+    WaitForChildToDie();
+    delete this;
+  }
+
+  void WaitForChildToDie() {
+    // Wait forever case.
+    if (timeout_ == 0) {
+      pid_t r = HANDLE_EINTR(waitpid(child_, NULL, 0));
+      if (r != child_) {
+        DPLOG(ERROR) << "While waiting for " << child_
+                     << " to terminate, we got the following result: " << r;
+      }
+      return;
+    }
+
+    // There's no good way to wait for a specific child to exit in a timed
+    // fashion. (No kqueue on Linux), so we just loop and sleep.
+
+    // Wait for 2 * timeout_ 500 milliseconds intervals.
+    for (unsigned i = 0; i < 2 * timeout_; ++i) {
+      PlatformThread::Sleep(TimeDelta::FromMilliseconds(500));
+      if (IsChildDead(child_))
+        return;
+    }
+
+    if (kill(child_, SIGKILL) == 0) {
+      // SIGKILL is uncatchable. Since the signal was delivered, we can
+      // just wait for the process to die now in a blocking manner.
+      if (HANDLE_EINTR(waitpid(child_, NULL, 0)) < 0)
+        DPLOG(WARNING) << "waitpid";
+    } else {
+      DLOG(ERROR) << "While waiting for " << child_ << " to terminate we"
+                  << " failed to deliver a SIGKILL signal (" << errno << ").";
+    }
+  }
+
+ private:
+  const pid_t child_;
+  // Number of seconds to wait, if 0 then wait forever and do not attempt to
+  // kill |child_|.
+  const unsigned timeout_;
+
+  DISALLOW_COPY_AND_ASSIGN(BackgroundReaper);
+};
+
+}  // namespace
+
+void EnsureProcessTerminated(ProcessHandle process) {
+  // If the child is already dead, then there's nothing to do.
+  if (IsChildDead(process))
+    return;
+
+  const unsigned timeout = 2;  // seconds
+  BackgroundReaper* reaper = new BackgroundReaper(process, timeout);
+  PlatformThread::CreateNonJoinable(0, reaper);
+}
+
+void EnsureProcessGetsReaped(ProcessHandle process) {
+  // If the child is already dead, then there's nothing to do.
+  if (IsChildDead(process))
+    return;
+
+  BackgroundReaper* reaper = new BackgroundReaper(process, 0);
+  PlatformThread::CreateNonJoinable(0, reaper);
+}
+
+#endif  // !defined(OS_MACOSX)
+
+}  // namespace base