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/***************************************************************************
* Copyright (C) 2015-2023 by Mihai Moldovan <ionic@ionic.de> *
* *
* This program is free software; you can redistribute it and/or modify *
* it under the terms of the GNU General Public License as published by *
* the Free Software Foundation; either version 2 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License for more details. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, write to the *
* Free Software Foundation, Inc., *
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
***************************************************************************/
#ifndef UNIXHELPER_H
#define UNIXHELPER_H
#include <QtCore/qglobal.h>
#include <unistd.h>
#ifdef Q_OS_UNIX
namespace unixhelper {
/*
* Unblocks all signals and installs a signal handler for SIGHUP,
* which calls kill_pgroup ().
*
* Should signal unblocking or installing the signal handler fail,
* an emergency exit is performed and
* the whole process group killed.
*
* The signals SIGINT, SIGTERM, SIGPIPE, SIGQUIT, SIGUSR1 and
* SIGUSR2 are ignored.
*
* Loops indefinitely afterwards.
*
* In this loop, the current parent PID is polled and compared against
* the original value passed via parameter parent.
* Should they mismatch, the parent died and kill_pgroup () is called.
*/
int unix_cleanup (const pid_t parent);
/*
* Wrapper for killing a whole process group.
* The "real" killing work is done by real_kill_pgroup ().
* This function tries to fork off another process and change
* the new function's process group ID.
* If any of these operations fail, killing the original process
* group ID will still continue, albeit with warning messages.
*
* signal may be any of:
* * -1 to indicate an error leading to emergency termination
* * SIGHUP as the standard signal that is sent when the
* group leader dies under specific circumstances
* (we cannot rely that this always happens, though,
* so a polling solution is needed, see unix_cleanup().)
* Other values are not handled.
*/
void kill_pgroup (const int signal);
/*
* Kills the whole process group.
* First, SIGTERM is sent to the group.
* A 10 seconds grace period is granted to make sure
* processes exit cleanly on their own.
* Lastly, SIGKILL is sent to the group -- which also
* implies the demise of this program.
*
* pgid is the process group ID to be killed.
*/
void real_kill_pgroup (const pid_t pgid);
}
#endif /* defined (Q_OS_UNIX) */
#endif /* !defined (UNIXHELPER_H) */
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