/*****************************************************************************\
 *  proctrack_pgid.c - process tracking via process group ID plugin.
 *****************************************************************************
 *  Copyright (C) 2005 The Regents of the University of California.
 *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
 *  Written by Morris Jette <jette1@llnl.gov> et. al.
 *  CODE-OCEC-09-009. All rights reserved.
 *
 *  This file is part of SLURM, a resource management program.
 *  For details, see <https://computing.llnl.gov/linux/slurm/>.
 *  Please also read the included file: DISCLAIMER.
 *
 *  SLURM 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.
 *
 *  In addition, as a special exception, the copyright holders give permission
 *  to link the code of portions of this program with the OpenSSL library under
 *  certain conditions as described in each individual source file, and
 *  distribute linked combinations including the two. You must obey the GNU
 *  General Public License in all respects for all of the code used other than
 *  OpenSSL. If you modify file(s) with this exception, you may extend this
 *  exception to your version of the file(s), but you are not obligated to do
 *  so. If you do not wish to do so, delete this exception statement from your
 *  version.  If you delete this exception statement from all source files in
 *  the program, then also delete it here.
 *
 *  SLURM 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 SLURM; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA.
\*****************************************************************************/

#if HAVE_CONFIG_H
#   include "config.h"
#endif

#if HAVE_STDINT_H
#  include <stdint.h>
#endif
#if HAVE_INTTYPES_H
#  include <inttypes.h>
#endif

#ifndef   __USE_XOPEN_EXTENDED
#  define __USE_XOPEN_EXTENDED /* getpgid */
#endif
#include <unistd.h>

#include <sys/types.h>
#include <signal.h>
#include <stdlib.h>
#include <slurm/slurm.h>
#include <slurm/slurm_errno.h>
#include "src/common/log.h"
#include "src/slurmd/slurmstepd/slurmstepd_job.h"

/*
 * These variables are required by the generic plugin interface.  If they
 * are not found in the plugin, the plugin loader will ignore it.
 *
 * plugin_name - a string giving a human-readable description of the
 * plugin.  There is no maximum length, but the symbol must refer to
 * a valid string.
 *
 * plugin_type - a string suggesting the type of the plugin or its
 * applicability to a particular form of data or method of data handling.
 * If the low-level plugin API is used, the contents of this string are
 * unimportant and may be anything.  SLURM uses the higher-level plugin
 * interface which requires this string to be of the form
 *
 *	<application>/<method>
 *
 * where <application> is a description of the intended application of
 * the plugin (e.g., "jobcomp" for SLURM job completion logging) and <method>
 * is a description of how this plugin satisfies that application.  SLURM will
 * only load job completion logging plugins if the plugin_type string has a
 * prefix of "jobcomp/".
 *
 * plugin_version - an unsigned 32-bit integer giving the version number
 * of the plugin.  If major and minor revisions are desired, the major
 * version number may be multiplied by a suitable magnitude constant such
 * as 100 or 1000.  Various SLURM versions will likely require a certain
 * minimum version for their plugins as the job completion logging API
 * matures.
 */
const char plugin_name[]      = "Process tracking via process group ID plugin";
const char plugin_type[]      = "proctrack/pgid";
const uint32_t plugin_version = 90;

/*
 * init() is called when the plugin is loaded, before any other functions
 * are called.  Put global initialization here.
 */
extern int init ( void )
{
	return SLURM_SUCCESS;
}

extern int fini ( void )
{
	return SLURM_SUCCESS;
}

extern int slurm_container_create ( slurmd_job_t *job )
{
	return SLURM_SUCCESS;
}

/*
 * Uses job step process group id.
 */
extern int slurm_container_add ( slurmd_job_t *job, pid_t pid )
{
	job->cont_id = (uint32_t)job->pgid;
	return SLURM_SUCCESS;
}

extern int slurm_container_signal  ( uint32_t id, int signal )
{
	pid_t pid = (pid_t) id;

	if (!id)	/* no container ID */
		return ESRCH;

	if (id == getpid() || id == getpgid(0)) {
		error("slurm_signal_container would kill caller!");
		return ESRCH;
	}

	return (int)killpg(pid, signal);
}

extern int slurm_container_destroy ( uint32_t id )
{
	return SLURM_SUCCESS;
}

extern uint32_t slurm_container_find(pid_t pid)
{
	pid_t rc = getpgid(pid);

	if (rc == -1)
		return (uint32_t) 0;
	else
		return (uint32_t) rc;
}

extern bool slurm_container_has_pid(uint32_t cont_id, pid_t pid)
{
	pid_t pgid = getpgid(pid);

	if (pgid == -1 || (uint32_t)pgid != cont_id)
		return false;

	return true;
}

extern int
slurm_container_wait(uint32_t cont_id)
{
	pid_t pgid = (pid_t)cont_id;
	int delay = 1;

	if (cont_id == 0 || cont_id == 1) {
		errno = EINVAL;
		return SLURM_ERROR;
	}

	/* Spin until the process group is gone. */
	while (killpg(pgid, 0) == 0) {
		slurm_container_signal(cont_id, SIGKILL);
		sleep(delay);
		if (delay < 120) {
			delay *= 2;
		} else {
			error("Unable to destroy container %u", cont_id);
		}
	}

	return SLURM_SUCCESS;
}

extern int
slurm_container_get_pids(uint32_t cont_id, pid_t **pids, int *npids)
{
	error("proctrack/pgid does not implement slurm_container_get_pids");
	return SLURM_ERROR;
}
