void ChildProcessTracker::attemptToReapProcess(
const std::pair<PidType,ExitHandler>& process)
{
// non-blocking wait for the child
int pid = process.first;
int status;
int result = waitPid(pid, &status);
// reaped the child
if (result == pid)
{
// confirm this was a real exit
bool exited = false;
if (WIFEXITED(status))
{
exited = true;
status = WEXITSTATUS(status);
}
else if (WIFSIGNALED(status))
{
exited = true;
}
// if it was a real exit (as opposed to a SIGSTOP or SIGCONT)
// then remove the pid from our table and fire the event
if (exited)
{
// all done with this pid
removeProcess(pid);
// call exit handler if we have one
ExitHandler exitHandler = process.second;
if (exitHandler)
exitHandler(pid, status);
}
else
{
boost::format fmt("Received SIGCHLD when child did not "
"actually exit (pid=%1%, status=%2%");
LOG_WARNING_MESSAGE(boost::str(fmt % pid % status));
}
}
// error occured
else if (result == -1)
{
Error error = systemError(errno, ERROR_LOCATION);
error.addProperty("pid", pid);
LOG_ERROR(error);
}
}
bool executeAndWait(const uid_t uid, const char* fname, const char* const* argv, int& status)
{
LOGD("Execute " << (uid == UNSPEC_UID ? "" : "as " + std::to_string(uid) + " ") << fname << argv);
pid_t pid = ::fork();
if (pid == -1) {
LOGE("Fork failed: " << getSystemErrorMessage());
return false;
}
if (pid == 0) {
if (uid != UNSPEC_UID && ::setuid(uid) < 0) {
LOGW("Failed to become uid(" << uid << "): " << getSystemErrorMessage());
::_exit(EXIT_FAILURE);
}
::execv(fname, const_cast<char* const*>(argv));
LOGE("execv(" << fname << ") failed: " << getSystemErrorMessage());
::_exit(EXIT_FAILURE);
}
return waitPid(pid, status);
}
