hyung-hwan/qse
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

renamed some signal handling functions in the App class

Browse Source
This commit is contained in:
hyung-hwan
2018-09-13 06:51:48 +00:00
parent c09a0161eb
commit c467a28f18
4 changed files with 78 additions and 51 deletions
Download Patch File Download Diff File Expand all files Collapse all files

76
qse/lib/si/App.cpp
View File

@ -85,8 +85,19 @@ App::~App () QSE_CPP_NOEXCEPT
SigScopedMutexLocker sml(g_app_mutex);
for (int i = 0; i < QSE_NSIGS; i++)
{
this->set_signal_subscription_no_mutex (i, SIGNAL_UNHANDLED);
// if the signal handler has not been removed before this application
// is destroyed and this is the last application subscribing to
// a signal, i arrange to set the signal handler to SIG_IGN as indicated by
// the third argument 'true' to set_signal_subscription_no_mutex().
// if the signal is not ignored, the signal received after destruction
// of this application object may lead to program crash as the handler
// is still associated with the destructed object.
// if the signal handler has been removed, the following function
// actual does nothing.
this->set_signal_subscription_no_mutex (i, SIGNAL_NEGLECTED, true);
}
if (this->_next_app) this->_next_app->_prev_app = this->_prev_app;
if (this->_prev_app) this->_prev_app->_next_app = this->_next_app;
if (this == g_app_top)
@ -321,10 +332,10 @@ int App::unset_signal_handler_no_mutex(int sig, int ignore)
if (sl._state == App::SIGNAL_ACCEPTED)
{
// the actual signal handler is called with the mutex locked.
// it must not call subscribeToSingal() or unsubscribeFromSingal()
// it must not call acceptSingal()/discardSignal()neglectSingal()
// from within the handler.
if (app->_guarded_child_pid >= 0) app->on_guard_signal (sig);
else app->on_signal (sig);
app->on_signal (sig);
}
app = next;
}
@ -335,28 +346,28 @@ void App::on_guard_signal (int sig)
::kill (this->_guarded_child_pid, sig);
}
App::SignalState App::getSignalSubscription (int sig) const
{
QSE_ASSERT (sig >= 0 && sig < QSE_NSIGS);
return this->_sig[sig]._state;
}
int App::setSignalSubscription (int sig, SignalState ss)
int App::setSignalSubscription (int sig, SignalState ss, bool ignore_if_unhandled)
{
QSE_ASSERT (sig >= 0 && sig < QSE_NSIGS);
SigScopedMutexLocker sml(g_app_mutex);
return this->set_signal_subscription_no_mutex(sig, ss);
return this->set_signal_subscription_no_mutex(sig, ss, ignore_if_unhandled);
}
int App::set_signal_subscription_no_mutex (int sig, SignalState reqstate)
int App::set_signal_subscription_no_mutex (int sig, SignalState reqstate, bool ignore_if_unhandled)
{
_SigLink& sl = this->_sig[sig];
if (QSE_UNLIKELY(sl._state == reqstate)) return 0; // no change
if (reqstate == SIGNAL_UNHANDLED)
if (reqstate == SIGNAL_NEGLECTED)
{
// accepted/ignored -> unhandled
// accepted/discarded -> neglected(unhandled)
QSE_ASSERT (g_app_sig[sig] != QSE_NULL);
if (g_app_sig[sig] == this)
@ -364,7 +375,9 @@ int App::set_signal_subscription_no_mutex (int sig, SignalState reqstate)
QSE_ASSERT (sl._prev == QSE_NULL);
if (!sl._next)
{
if (App::unset_signal_handler_no_mutex(sig, true) <= -1) return -1;
// this is the last application subscribing to the signal.
// let's get rid of the signal handler
if (App::unset_signal_handler_no_mutex(sig, ignore_if_unhandled) <= -1) return -1;
}
g_app_sig[sig] = sl._next;
}
@ -375,9 +388,9 @@ int App::set_signal_subscription_no_mutex (int sig, SignalState reqstate)
sl._next = QSE_NULL;
sl._state = reqstate;
}
else if (QSE_LIKELY(sl._state == SIGNAL_UNHANDLED))
else if (QSE_LIKELY(sl._state == SIGNAL_NEGLECTED))
{
// unhandled -> accepted/ignored
// neglected(unhandled) -> accepted/discarded
QSE_ASSERT (sl._prev == QSE_NULL && sl._next == QSE_NULL);
App* xapp = g_app_sig[sig];
@ -400,7 +413,7 @@ int App::set_signal_subscription_no_mutex (int sig, SignalState reqstate)
// roll back
g_app_sig[sig] = xapp;
if (xapp) xapp->_sig[sig]._prev = xapp_xprev;
sl._state = SIGNAL_UNHANDLED;
sl._state = SIGNAL_NEGLECTED;
sl._next = QSE_NULL;
QSE_ASSERT (sl._prev == QSE_NULL);
return -1;
@ -423,25 +436,36 @@ int App::guardProcess (const SignalSet& signals, const qse_mchar_t* proc_name)
{
SignalState old_ss[QSE_NSIGS];
for (int i = 0; i < QSE_NSIGS; i++)
{
if (signals.isSet(i))
{
old_ss[i] = this->getSignalSubscription(i);
this->setSignalSubscription (i, SIGNAL_ACCEPTED);
}
}
while (1)
{
pid_t pid = ::fork();
if (pid == -1) return -1;
if (pid == 0)
{
::setpgid (0, 0); // change the process group id.
break; // child
}
// child process
this->_guarded_child_pid = -1;
for (int i = 0; i < QSE_NSIGS; i++)
{
if (signals.isSet(i))
for (int i = 0; i < QSE_NSIGS; i++)
{
old_ss[i] = this->getSignalSubscription(i);
this->setSignalSubscription (i, SIGNAL_ACCEPTED);
if (signals.isSet(i)) this->setSignalSubscription (i, old_ss[i]);
}
::setpgid (0, 0); // change the process group id.
break;
}
// ===============================================
// the guardian(parent) process
// ===============================================
this->_guarded_child_pid = pid;
int status;
@ -455,17 +479,15 @@ int App::guardProcess (const SignalSet& signals, const qse_mchar_t* proc_name)
// ------------------------------------------------------
}
this->_guarded_child_pid = -1;
for (int i = 0; i < QSE_NSIGS; i++)
{
if (signals.isSet(i)) this->setSignalSubscription (i, old_ss[i]);
}
if (WIFEXITED(status))
{
if (WEXITSTATUS(status) == 0)
{
// the child has terminated normally and successfully.
for (int i = 0; i < QSE_NSIGS; i++)
{
if (signals.isSet(i)) this->setSignalSubscription (i, old_ss[i]);
}
return 0;
}
}