/****************************************************************************\
 *  slurm_pmi.c - PMI support functions internal to SLURM
 *****************************************************************************
 *  Copyright (C) 2005-2006 The Regents of the University of California.
 *  Produced at Lawrence Livermore National Laboratory (cf, DISCLAIMER).
 *  Written by Morris Jette <jette1@llnl.gov>.
 *  CODE-OCEC-09-009. All rights reserved.
 *
 *  This file is part of Slurm, a resource management program.
 *  For details, see <https://slurm.schedmd.com/>.
 *  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.
\*****************************************************************************/

#include <stdlib.h>
#include <sys/time.h>

#include "slurm/slurm.h"
#include "slurm/slurm_errno.h"

#include "src/api/slurm_pmi.h"
#include "src/common/slurm_protocol_api.h"
#include "src/common/slurm_protocol_defs.h"
#include "src/common/forward.h"
#include "src/common/read_config.h"
#include "src/common/strlcpy.h"
#include "src/common/xmalloc.h"
#include "src/common/fd.h"
#include "src/common/slurm_auth.h"

#define DEFAULT_PMI_TIME 500
#define MAX_RETRIES      5

int pmi_fd = -1;
int pmi_time = 0;
uint16_t srun_port = 0;
slurm_addr_t srun_addr;

static void _delay_rpc(int pmi_rank, int pmi_size);
static int  _forward_comm_set(kvs_comm_set_t *kvs_set_ptr);
static int  _get_addr(void);
static void _set_pmi_time(void);

/* Delay an RPC to srun in order to avoid overwhelming the srun command.
 * The delay is based upon the number of tasks, this task's rank, and PMI_TIME.
 * This logic depends upon synchronized clocks across the cluster. */
static void _delay_rpc(int pmi_rank, int pmi_size)
{
	struct timeval tv1, tv2;
	uint32_t cur_time;	/* current time in usec (just 9 digits) */
	uint32_t tot_time;	/* total time expected for all RPCs */
	uint32_t offset_time;	/* relative time within tot_time */
	uint32_t target_time;	/* desired time to issue the RPC */
	uint32_t delta_time, error_time;
	int retries = 0;

	if (pmi_rank == 0)	/* Rank 0 has extra communications with no */
		return;		/* risk of induced packet storm */

	_set_pmi_time();

again:	if (gettimeofday(&tv1, NULL)) {
		usleep(pmi_rank * pmi_time);
		return;
	}

	cur_time = ((tv1.tv_sec % 1000) * 1000000) + tv1.tv_usec;
	tot_time = pmi_size * pmi_time;
	offset_time = cur_time % tot_time;
	target_time = pmi_rank * pmi_time;
	if (target_time < offset_time)
		delta_time = target_time - offset_time + tot_time;
	else
		delta_time = target_time - offset_time;
	if (usleep(delta_time)) {
		if (errno == EINVAL)
			usleep(900000);
		/* errno == EINTR */
		goto again;
	}

	/* Verify we are active at the right time. If current time is different
	 * from target by more than 15*pmi_time, then start over. If PMI_TIME
	 * is set appropriately, then srun should have no more than 30 RPCs
	 * in the queue at one time in the worst case. */
	if (gettimeofday(&tv2, NULL))
		return;
	tot_time = (tv2.tv_sec - tv1.tv_sec) * 1000000;
	tot_time += tv2.tv_usec;
	tot_time -= tv1.tv_usec;
	if (tot_time >= delta_time)
		error_time = tot_time - delta_time;
	else
		error_time = delta_time - tot_time;
	if (error_time > (15*pmi_time)) {	/* too far off */
#if 0
		info("delta=%u tot=%u err=%u",
			delta_time, tot_time, error_time);
#endif
		if ((++retries) <= 2)
			goto again;
	}
}

static int _get_addr(void)
{
	char *env_host, *env_port;

	if (srun_port)
		return SLURM_SUCCESS;

	env_host = getenv("SLURM_SRUN_COMM_HOST");
	env_port = getenv("SLURM_SRUN_COMM_PORT");
	if (!env_host || !env_port)
		return SLURM_ERROR;

	srun_port = (uint16_t) atol(env_port);
	slurm_set_addr(&srun_addr, srun_port, env_host);
	return SLURM_SUCCESS;
}

static void _set_pmi_time(void)
{
	char *tmp, *endptr;

	if (pmi_time)
		return;

	tmp = getenv("PMI_TIME");
	if (tmp == NULL) {
		pmi_time = DEFAULT_PMI_TIME;
		return;
	}

	pmi_time = strtol(tmp, &endptr, 10);
	if ((pmi_time <= 0) || (endptr[0] != '\0')) {
		error("Invalid PMI_TIME: %s", tmp);
		pmi_time = DEFAULT_PMI_TIME;
	}
}

/* Transmit PMI Keyval space data */
int slurm_send_kvs_comm_set(kvs_comm_set_t *kvs_set_ptr,
		int pmi_rank, int pmi_size)
{
	slurm_msg_t msg_send;
	int rc, retries = 0, timeout = 0;

	if (kvs_set_ptr == NULL)
		return EINVAL;

	if ((rc = _get_addr()) != SLURM_SUCCESS)
		return rc;
	_set_pmi_time();

	slurm_msg_t_init(&msg_send);
	msg_send.address = srun_addr;
	msg_send.msg_type = PMI_KVS_PUT_REQ;
	msg_send.data = (void *) kvs_set_ptr;

	/* Send the RPC to the local srun communication manager.
	 * Since the srun can be sent thousands of messages at
	 * the same time and refuse some connections, retry as
	 * needed. Spread out messages by task's rank. Also
	 * increase the timeout if many tasks since the srun
	 * command is very overloaded.
	 * We also increase the timeout (default timeout is
	 * 10 secs). */
	_delay_rpc(pmi_rank, pmi_size);
	if      (pmi_size > 4000)	/* 240 secs */
		timeout = slurm_get_msg_timeout() * 24000;
	else if (pmi_size > 1000)	/* 120 secs */
		timeout = slurm_get_msg_timeout() * 12000;
	else if (pmi_size > 100)	/* 50 secs */
		timeout = slurm_get_msg_timeout() * 5000;
	else if (pmi_size > 10)		/* 20 secs */
		timeout = slurm_get_msg_timeout() * 2000;

	while (slurm_send_recv_rc_msg_only_one(&msg_send, &rc, timeout) < 0) {
		if (retries++ > MAX_RETRIES) {
			error("slurm_send_kvs_comm_set: %m");
			return SLURM_ERROR;
		} else
			debug("send_kvs retry %d", retries);
		_delay_rpc(pmi_rank, pmi_size);
	}

	return rc;
}

/* Wait for barrier and get full PMI Keyval space data */
int  slurm_get_kvs_comm_set(kvs_comm_set_t **kvs_set_ptr,
			    int pmi_rank, int pmi_size)
{
	int rc, srun_fd, retries = 0, timeout = 0;
	slurm_msg_t msg_send, msg_rcv;
	slurm_addr_t slurm_addr, srun_reply_addr;
	char hostname[64];
	uint16_t port;
	kvs_get_msg_t data;
	char *env_pmi_ifhn;

	if (kvs_set_ptr == NULL)
		return EINVAL;
	*kvs_set_ptr = NULL;	/* initialization */

	if ((rc = _get_addr()) != SLURM_SUCCESS) {
		error("_get_addr: %m");
		return rc;
	}

	_set_pmi_time();

	if (pmi_fd < 0) {
		if ((pmi_fd = slurm_init_msg_engine_port(0)) < 0) {
			error("slurm_init_msg_engine_port: %m");
			return SLURM_ERROR;
		}
		fd_set_blocking(pmi_fd);
	}
	if (slurm_get_stream_addr(pmi_fd, &slurm_addr) < 0) {
		error("slurm_get_stream_addr: %m");
		return SLURM_ERROR;
	}
	/* hostname is not set here, so slurm_get_addr fails
	slurm_get_addr(&slurm_addr, &port, hostname, sizeof(hostname)); */
	port = ntohs(slurm_addr.sin_port);
	if ((env_pmi_ifhn = getenv("SLURM_PMI_RESP_IFHN")))
		strlcpy(hostname, env_pmi_ifhn, sizeof(hostname));
	else
		gethostname_short(hostname, sizeof(hostname));

	data.task_id = pmi_rank;
	data.size = pmi_size;
	data.port = port;
	data.hostname = hostname;
	slurm_msg_t_init(&msg_send);
	slurm_msg_t_init(&msg_rcv);
	msg_send.address = srun_addr;
	msg_send.msg_type = PMI_KVS_GET_REQ;
	msg_send.data = &data;

	/* Send the RPC to the local srun communication manager.
	 * Since the srun can be sent thousands of messages at
	 * the same time and refuse some connections, retry as
	 * needed. Wait until all key-pairs have been sent by
	 * all tasks then spread out messages by task's rank.
	 * Also increase the message timeout if many tasks
	 * since the srun command can get very overloaded (the
	 * default timeout is 10 secs).
	 */
	_delay_rpc(pmi_rank, pmi_size);
	if      (pmi_size > 4000)	/* 240 secs */
		timeout = slurm_get_msg_timeout() * 24000;
	else if (pmi_size > 1000)	/* 120 secs */
		timeout = slurm_get_msg_timeout() * 12000;
	else if (pmi_size > 100)	/* 60 secs */
		timeout = slurm_get_msg_timeout() * 6000;
	else if (pmi_size > 10)		/* 20 secs */
		timeout = slurm_get_msg_timeout() * 2000;

	while (slurm_send_recv_rc_msg_only_one(&msg_send, &rc, timeout) < 0) {
		if (retries++ > MAX_RETRIES) {
			error("slurm_get_kvs_comm_set: %m");
			return SLURM_ERROR;
		} else
			debug("get kvs retry %d", retries);
		_delay_rpc(pmi_rank, pmi_size);
	}
	if (rc != SLURM_SUCCESS) {
		error("slurm_get_kvs_comm_set error_code=%d", rc);
		return rc;
	}

	/* get the message after all tasks reach the barrier */
	srun_fd = slurm_accept_msg_conn(pmi_fd, &srun_reply_addr);
	if (srun_fd < 0) {
		error("slurm_accept_msg_conn: %m");
		return errno;
	}

	while ((rc = slurm_receive_msg(srun_fd, &msg_rcv, timeout)) != 0) {
		if (errno == EINTR)
			continue;
		error("slurm_receive_msg: %m");
		close(srun_fd);
		return errno;
	}
	if (msg_rcv.auth_cred)
		(void)g_slurm_auth_destroy(msg_rcv.auth_cred);

	if (msg_rcv.msg_type != PMI_KVS_GET_RESP) {
		error("slurm_get_kvs_comm_set msg_type=%d", msg_rcv.msg_type);
		close(srun_fd);
		return SLURM_UNEXPECTED_MSG_ERROR;
	}
	if (slurm_send_rc_msg(&msg_rcv, SLURM_SUCCESS) < 0)
		error("slurm_send_rc_msg: %m");

	close(srun_fd);
	*kvs_set_ptr = msg_rcv.data;

	rc = _forward_comm_set(*kvs_set_ptr);
	return rc;
}

/* Forward keypair info to other tasks as required.
 * Clear message forward structure upon completion.
 * The messages are forwarded sequentially. */
static int _forward_comm_set(kvs_comm_set_t *kvs_set_ptr)
{
	int i, rc = SLURM_SUCCESS;
	int tmp_host_cnt = kvs_set_ptr->host_cnt;
	slurm_msg_t msg_send;
	int msg_rc;

	kvs_set_ptr->host_cnt = 0;
	for (i=0; i<tmp_host_cnt; i++) {
		if (kvs_set_ptr->kvs_host_ptr[i].port == 0)
			continue;	/* empty */
		slurm_msg_t_init(&msg_send);
		msg_send.msg_type = PMI_KVS_GET_RESP;
		msg_send.data = (void *) kvs_set_ptr;
		slurm_set_addr(&msg_send.address,
			kvs_set_ptr->kvs_host_ptr[i].port,
			kvs_set_ptr->kvs_host_ptr[i].hostname);
		if (slurm_send_recv_rc_msg_only_one(&msg_send,
				&msg_rc, 0) < 0) {
			error("Could not forward msg to %s",
				kvs_set_ptr->kvs_host_ptr[i].hostname);
			msg_rc = 1;
		}
		rc = MAX(rc, msg_rc);
		xfree(kvs_set_ptr->kvs_host_ptr[i].hostname);
	}
	xfree(kvs_set_ptr->kvs_host_ptr);
	return rc;
}

/* Finalization processing */
void slurm_pmi_finalize(void)
{
	if (pmi_fd >= 0) {
		close(pmi_fd);
		pmi_fd = -1;
	}
	srun_port = 0;
}
