/*
 * Copyright (C)      2022 Colin Ian King.
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 */
#include "stress-ng.h"

#define MIN_MUTEX_PROCS		(2)
#define MAX_MUTEX_PROCS		(64)
#define DEFAULT_MUTEX_PROCS	(2)

static const stress_help_t help[] = {
	{ NULL,	"mutex N",	"start N workers exercising mutex operations" },
	{ NULL,	"mutex-ops N",	"stop after N mutex bogo operations" },
	{ NULL, "mutex-procs N","select the number of concurrent processes" },
	{ NULL,	NULL,		NULL }
};

static int stress_set_mutex_procs(const char *opt)
{
	uint64_t mutex_procs;

	mutex_procs = stress_get_uint64(opt);
	stress_check_range("mutex-procs", mutex_procs,
		MIN_MUTEX_PROCS, MAX_MUTEX_PROCS);
	return stress_set_setting("mutex-procs", TYPE_ID_UINT64, &mutex_procs);
}

static const stress_opt_set_func_t opt_set_funcs[] = {
	{ OPT_mutex_procs,	stress_set_mutex_procs },
	{ 0,			NULL }
};

#if defined(HAVE_PTHREAD_MUTEXATTR_T) &&		\
    defined(HAVE_PTHREAD_MUTEXATTR_INIT) &&		\
    defined(HAVE_PTHREAD_MUTEXATTR_DESTROY) &&		\
    defined(HAVE_PTHREAD_MUTEXATTR_SETPRIOCEILING) &&	\
    defined(HAVE_PTHREAD_MUTEXATTR_SETPROTOCOL)
#define HAVE_PTHREAD_MUTEXATTR
#endif

#if defined(_POSIX_PRIORITY_SCHEDULING) &&	\
    defined(HAVE_LIB_PTHREAD) &&		\
    defined(HAVE_PTHREAD_MUTEX_T) &&		\
    defined(HAVE_PTHREAD_MUTEX_INIT) &&		\
    defined(HAVE_PTHREAD_MUTEX_DESTROY) &&	\
    defined(HAVE_PTHREAD_SETSCHEDPARAM) &&	\
    defined(HAVE_SCHED_GET_PRIORITY_MIN) &&	\
    defined(HAVE_SCHED_GET_PRIORITY_MAX) &&	\
    defined(SCHED_FIFO)

pthread_mutex_t mutex;

typedef struct {
	const stress_args_t *args;
	int prio_min;
	int prio_max;
	pthread_t pthread;
	int ret;
} pthread_info_t;

/*
 *  mutex_exercise()
 *	exercise the mutex
 */
static void *mutex_exercise(void *arg)
{
	pthread_info_t *pthread_info = (pthread_info_t *)arg;
	const stress_args_t *args = pthread_info->args;
	static void *nowt = NULL;
	int max = (pthread_info->prio_max * 7) / 8;
#if defined(HAVE_PTHREAD_MUTEXATTR)
	int mutexattr_ret;
	pthread_mutexattr_t mutexattr;
#endif

	stress_mwc_reseed();

#if defined(HAVE_PTHREAD_MUTEXATTR)
	/*
	 *  Attempt to use priority inheritance on mutex
	 */
	mutexattr_ret = pthread_mutexattr_init(&mutexattr);
	if (mutexattr_ret == 0) {
		int ret;

		ret = pthread_mutexattr_setprotocol(&mutexattr, PTHREAD_PRIO_INHERIT);
		(void)ret;
		ret = pthread_mutexattr_setprioceiling(&mutexattr, max);
		(void)ret;
	}
#endif

	do {
		struct sched_param param;

		param.sched_priority = max > 0 ? (int)stress_mwc32() % max : max;
		(void)pthread_setschedparam(pthread_info->pthread, SCHED_FIFO, &param);
		if (pthread_mutex_lock(&mutex) < 0) {
			pr_fail("%s: pthread_mutex_lock failed, errno=%d (%s)\n",
				args->name, errno, strerror(errno));
			break;
		}
		param.sched_priority = pthread_info->prio_min;
		(void)pthread_setschedparam(pthread_info->pthread, SCHED_FIFO, &param);

		inc_counter(args);
		shim_sched_yield();

		if (pthread_mutex_unlock(&mutex) < 0) {
			pr_fail("%s: pthread_mutex_unlock failed, errno=%d (%s)\n",
				args->name, errno, strerror(errno));
			break;
		}
	} while (keep_stressing(args));

	(void)kill(args->pid, SIGALRM);
#if defined(HAVE_PTHREAD_MUTEXATTR)
	if (mutexattr_ret == 0) {
		(void)pthread_mutexattr_destroy(&mutexattr);
	}
#endif

	return &nowt;
}

/*
 *  stress_mutex()
 *	stress system with priority changing mutex lock/unlocks
 */
static int stress_mutex(const stress_args_t *args)
{
	size_t i;
	bool created = false;
	int prio_min, prio_max;
	pthread_info_t pthread_info[DEFAULT_MUTEX_PROCS];
	uint64_t mutex_procs = DEFAULT_MUTEX_PROCS;

	if (!stress_get_setting("mutex-procs", &mutex_procs)) {
		if (g_opt_flags & OPT_FLAGS_MAXIMIZE)
			mutex_procs = MAX_MUTEX_PROCS;
		if (g_opt_flags & OPT_FLAGS_MINIMIZE)
			mutex_procs = MIN_MUTEX_PROCS;
	}

	(void)memset(&pthread_info, 0, sizeof(pthread_info));

	if (pthread_mutex_init(&mutex, NULL) < 0) {
		pr_fail("pthread_mutex_init failed: errno=%d: "
			"(%s)\n", errno, strerror(errno));
		return EXIT_FAILURE;
	}

	prio_min = sched_get_priority_min(SCHED_FIFO);
	prio_max = sched_get_priority_max(SCHED_FIFO);

	stress_set_proc_state(args->name, STRESS_STATE_RUN);

	for (i = 0; i < DEFAULT_MUTEX_PROCS; i++) {
		pthread_info[i].args = args;
		pthread_info[i].prio_min = prio_min;
		pthread_info[i].prio_max = prio_max;
		pthread_info[i].ret = pthread_create(&pthread_info[i].pthread, NULL,
                                mutex_exercise, (void *)&pthread_info[i]);
		if ((pthread_info[i].ret) && (pthread_info[i].ret != EAGAIN)) {
			pr_fail("%s: pthread create failed, errno=%d (%s)\n",
				args->name, pthread_info[i].ret, strerror(pthread_info[i].ret));
			break;
		}
		if (!keep_stressing_flag())
			break;
		created = true;
	}

	if (!created) {
		pr_inf("%s: could not create any pthreads\n", args->name);
		return EXIT_NO_RESOURCE;
	}

	/* Wait for termination */
	while (keep_stressing(args))
		pause();

	stress_set_proc_state(args->name, STRESS_STATE_DEINIT);

	for (i = 0; i < DEFAULT_MUTEX_PROCS; i++) {
		int ret;

		if (pthread_info[i].ret)
			continue;

		ret = pthread_join(pthread_info[i].pthread, NULL);
		(void)ret;
	}
	(void)pthread_mutex_destroy(&mutex);

	return EXIT_SUCCESS;
}

stressor_info_t stress_mutex_info = {
	.stressor = stress_mutex,
	.class = CLASS_OS | CLASS_SCHEDULER,
	.verify = VERIFY_ALWAYS,
	.opt_set_funcs = opt_set_funcs,
	.help = help
};
#else
stressor_info_t stress_mutex_info = {
	.stressor = stress_not_implemented,
	.class = CLASS_OS | CLASS_SCHEDULER,
	.opt_set_funcs = opt_set_funcs,
	.help = help
};
#endif