/*

 * iSCSI Administrator Utility Socket Interface

 *

 * Copyright (C) 2004 Dmitry Yusupov, Alex Aizman

 * Copyright (C) 2006 Mike Christie

 * Copyright (C) 2006 Red Hat, Inc. All rights reserved.

 * maintained by open-iscsi@googlegroups.com

 *

 * Originally based on:

 * (C) 2004 FUJITA Tomonori <tomof@acm.org>

 *

 * 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.

 *

 * See the file COPYING included with this distribution for more details.

 */

#include <stdlib.h>

#include <errno.h>

#include <unistd.h>

#include <pwd.h>

#include <sys/un.h>

#include "iscsid.h"

#include "idbm.h"

#include "mgmt_ipc.h"

#include "event_poll.h"

#include "log.h"

#include "transport.h"

#include "sysdeps.h"

#include "iscsi_ipc.h"

#include "iscsi_err.h"

#include "iscsi_util.h"

#include "iscsid_req.h"

#define PEERUSER_MAX	64

#define EXTMSG_MAX	(64 * 1024)

#define SD_SOCKET_FDS_START 3

int

mgmt_ipc_listen(void)

{

	int fd, err, addr_len;

	struct sockaddr_un addr;

	/* first check if we have fd handled by systemd */

	fd = mgmt_ipc_systemd();

	if (fd >= 0)

		return fd;

	/* manually establish a socket */

	fd = socket(AF_LOCAL, SOCK_STREAM, 0);

	if (fd < 0) {

		log_error("Can not create IPC socket");

		return fd;

	}

	addr_len = setup_abstract_addr(&addr, iscsid_namespace);

	if ((err = bind(fd, (struct sockaddr *) &addr, addr_len)) < 0 ) {

		log_error("Can not bind IPC socket");

		close(fd);

		return err;

	}

	if ((err = listen(fd, 32)) < 0) {

		log_error("Can not listen IPC socket");

		close(fd);

		return err;

	}

	return fd;

}

int mgmt_ipc_systemd(void)

{

	const char *env;

	env = getenv("LISTEN_PID");

	if (!env || (strtoul(env, NULL, 10) != getpid()))

		return -EINVAL;

	env = getenv("LISTEN_FDS");

	if (!env)

		return -EINVAL;

	if (strtoul(env, NULL, 10) != 1) {

		log_error("Did not receive exactly one IPC socket from systemd");

		return -EINVAL;

	}

	return SD_SOCKET_FDS_START;

}

void

mgmt_ipc_close(int fd)

{

	event_loop_exit(NULL);

	if (fd >= 0)

		close(fd);

}

static int 

mgmt_ipc_session_login(queue_task_t *qtask)

{

	return session_login_task(&qtask->req.u.session.rec, qtask);

}

static int

mgmt_ipc_session_getstats(queue_task_t *qtask)

{

	int sid = qtask->req.u.session.sid;

	iscsi_session_t *session;

	int rc;

	if (!(session = session_find_by_sid(sid)))

		return ISCSI_ERR_SESS_NOT_FOUND;

	rc = ipc->get_stats(session->t->handle,

		session->id, session->conn[0].id,

		(void *)&qtask->rsp.u.getstats,

		MGMT_IPC_GETSTATS_BUF_MAX);

	if (rc) {

		log_error("get_stats(): IPC error %d "

			"session [%02d]", rc, sid);

		return ISCSI_ERR_INTERNAL;

	}

	mgmt_ipc_write_rsp(qtask, ISCSI_SUCCESS);

	return ISCSI_SUCCESS;

}

static int

mgmt_ipc_send_targets(queue_task_t *qtask)

{

	iscsiadm_req_t *req = &qtask->req;

	int err;

	err = iscsi_host_send_targets(qtask, req->u.st.host_no,

					  req->u.st.do_login,

					  &req->u.st.ss);

	mgmt_ipc_write_rsp(qtask, err);

	return ISCSI_SUCCESS;

}

static int

mgmt_ipc_session_logout(queue_task_t *qtask)

{

	return session_logout_task(qtask->req.u.session.sid, qtask);

}

static int

mgmt_ipc_session_sync(queue_task_t *qtask)

{

	struct ipc_msg_session *session= &qtask->req.u.session;

	return iscsi_sync_session(&session->rec, qtask, session->sid);

}

static int

mgmt_ipc_cfg_initiatorname(queue_task_t *qtask)

{

	if (dconfig->initiator_name)

		strcpy(qtask->rsp.u.config.var, dconfig->initiator_name);

	mgmt_ipc_write_rsp(qtask, ISCSI_SUCCESS);

	return ISCSI_SUCCESS;

}

static int

mgmt_ipc_session_info(queue_task_t *qtask)

{

	int sid = qtask->req.u.session.sid;

	iscsi_session_t *session;

	struct ipc_msg_session_state *info;

	if (!(session = session_find_by_sid(sid))) {

		log_debug(1, "session with sid %d not found!", sid);

		return ISCSI_ERR_SESS_NOT_FOUND;

	}

	info = &qtask->rsp.u.session_state;

	info->conn_state = session->conn[0].state;

	info->session_state = session->r_stage;

	mgmt_ipc_write_rsp(qtask, ISCSI_SUCCESS);

	return ISCSI_SUCCESS;

}

static int

mgmt_ipc_cfg_initiatoralias(queue_task_t *qtask)

{

	strcpy(qtask->rsp.u.config.var, dconfig->initiator_alias);

	mgmt_ipc_write_rsp(qtask, ISCSI_SUCCESS);

	return ISCSI_SUCCESS;

}

static int

mgmt_ipc_cfg_filename(queue_task_t *qtask)

{

	strcpy(qtask->rsp.u.config.var, dconfig->config_file);

	mgmt_ipc_write_rsp(qtask, ISCSI_SUCCESS);

	return ISCSI_SUCCESS;

}

static int

mgmt_ipc_conn_add(queue_task_t *qtask)

{

	return ISCSI_ERR;

}

static int

mgmt_ipc_immediate_stop(queue_task_t *qtask)

{

	event_loop_exit(qtask);

	return ISCSI_SUCCESS;

}

static int

mgmt_ipc_conn_remove(queue_task_t *qtask)

{

	return ISCSI_ERR;

}

/*

 * Parse a list of strings, encoded as a 32bit

 * length followed by the string itself (not necessarily

 * NUL-terminated).

 */

static int

mgmt_ipc_parse_strings(queue_task_t *qtask, char ***result)

{

	char		*data, *endp, **argv = NULL;

	unsigned int	left, argc;

again:

	data = qtask->payload;

	left = qtask->req.payload_len;

	endp = NULL;

	argc = 0;

	while (left) {

		uint32_t len;

		if (left < 4)

			return -1;

		memcpy(&len, data, 4);

		data += 4;

		if (endp)

			*endp = '\0';

		if (len > left)

			return -1;

		if (argv) {

			argv[argc] = (char *) data;

			endp = data + len;

		}

		data += len;

		argc++;

	}

	if (endp)

		*endp = '\0';

	if (argv == NULL) {

		argv = malloc((argc + 1) * sizeof(char *));

		*result = argv;

		goto again;

	}

	argv[argc] = NULL;

	return argc;

}

static int

mgmt_ipc_notify_common(queue_task_t *qtask, int (*handler)(int, char **))

{

	char	**argv = NULL;

	int	argc, err = ISCSI_ERR;

	argc = mgmt_ipc_parse_strings(qtask, &argv);

	if (argc > 0)

		err = handler(argc, argv);

	if (argv)

		free(argv);

	mgmt_ipc_write_rsp(qtask, err);

	return ISCSI_SUCCESS;

}

/* Replace these dummies as you implement them

   elsewhere */

static int

iscsi_discovery_add_node(int argc, char **argv)

{

	return ISCSI_SUCCESS;

}

static int

iscsi_discovery_del_node(int argc, char **argv)

{

	return ISCSI_SUCCESS;

}

static int

iscsi_discovery_add_portal(int argc, char **argv)

{

	return ISCSI_SUCCESS;

}

static int

iscsi_discovery_del_portal(int argc, char **argv)

{

	return ISCSI_SUCCESS;

}

static int

mgmt_ipc_notify_add_node(queue_task_t *qtask)

{

	return mgmt_ipc_notify_common(qtask, iscsi_discovery_add_node);

}

static int

mgmt_ipc_notify_del_node(queue_task_t *qtask)

{

	return mgmt_ipc_notify_common(qtask, iscsi_discovery_del_node);

}

static int

mgmt_ipc_notify_add_portal(queue_task_t *qtask)

{

	return mgmt_ipc_notify_common(qtask, iscsi_discovery_add_portal);

}

static int

mgmt_ipc_notify_del_portal(queue_task_t *qtask)

{

	return mgmt_ipc_notify_common(qtask, iscsi_discovery_del_portal);

}

static int

mgmt_peeruser(int sock, char *user)

{

	/* Linux style: use getsockopt(SO_PEERCRED) */

	struct ucred peercred;

	socklen_t so_len = sizeof(peercred);

	struct passwd *pass;

	errno = 0;

	if (getsockopt(sock, SOL_SOCKET, SO_PEERCRED, &peercred,

		&so_len) != 0 || so_len != sizeof(peercred)) {

		/* We didn't get a valid credentials struct. */

		log_error("peeruser_unux: error receiving credentials: %m");

		return 0;

	}

	pass = getpwuid(peercred.uid);

	if (pass == NULL) {

		log_error("peeruser_unix: unknown local user with uid %d",

				(int) peercred.uid);

		return 0;

	}

	strlcpy(user, pass->pw_name, PEERUSER_MAX);

	return 1;

}

static void

mgmt_ipc_destroy_queue_task(queue_task_t *qtask)

{

	if (qtask->mgmt_ipc_fd >= 0)

		close(qtask->mgmt_ipc_fd);

	if (qtask->payload)

		free(qtask->payload);

	if (qtask->allocated)

		free(qtask);

}

/*

 * Send the IPC response and destroy the queue_task.

 * The recovery code uses a qtask which is allocated as

 * part of a larger structure, and we don't want it to

 * get freed when we come here. This is what qtask->allocated

 * is for.

 */

void

mgmt_ipc_write_rsp(queue_task_t *qtask, int err)

{

	if (!qtask)

		return;

	log_debug(4, "%s: rsp to fd %d", __FUNCTION__,

		 qtask->mgmt_ipc_fd);

	if (qtask->mgmt_ipc_fd < 0) {

		mgmt_ipc_destroy_queue_task(qtask);

		return;

	}

	qtask->rsp.err = err;

	if (write(qtask->mgmt_ipc_fd, &qtask->rsp, sizeof(qtask->rsp)) < 0)

		log_error("IPC qtask write failed: %s", strerror(errno));

	mgmt_ipc_destroy_queue_task(qtask);

}

static int

mgmt_ipc_read_data(int fd, void *ptr, size_t len)

{

	int	n;

	while (len) {

		n = read(fd, ptr, len);

		if (n < 0) {

			if (errno == EINTR)

				continue;

			return -EIO;

		}

		if (n == 0) {

			/* Client closed connection */

			return -EIO;

		}

		ptr += n;

		len -= n;

	}

	return 0;

}

static int

mgmt_ipc_read_req(queue_task_t *qtask)

{

	iscsiadm_req_t *req = &qtask->req;

	int	rc;

	rc = mgmt_ipc_read_data(qtask->mgmt_ipc_fd, req, sizeof(*req));

	if (rc >= 0 && req->payload_len > 0) {

		/* Limit what we accept */

		if (req->payload_len > EXTMSG_MAX)

			return -EIO;

		/* Remember the allocated pointer in the

		 * qtask - it will be freed by write_rsp.

		 * Note: we allocate one byte in excess

		 * so we can append a NUL byte. */

		qtask->payload = malloc(req->payload_len + 1);

		rc = mgmt_ipc_read_data(qtask->mgmt_ipc_fd,

				qtask->payload,

				req->payload_len);

	}

	return rc;

}

static mgmt_ipc_fn_t *	mgmt_ipc_functions[__MGMT_IPC_MAX_COMMAND] = {

[MGMT_IPC_SESSION_LOGIN]	= mgmt_ipc_session_login,

[MGMT_IPC_SESSION_LOGOUT]	= mgmt_ipc_session_logout,

[MGMT_IPC_SESSION_SYNC]		= mgmt_ipc_session_sync,

[MGMT_IPC_SESSION_STATS]	= mgmt_ipc_session_getstats,

[MGMT_IPC_SEND_TARGETS]		= mgmt_ipc_send_targets,

[MGMT_IPC_SESSION_INFO]		= mgmt_ipc_session_info,

[MGMT_IPC_CONN_ADD]		= mgmt_ipc_conn_add,

[MGMT_IPC_CONN_REMOVE]		= mgmt_ipc_conn_remove,

[MGMT_IPC_CONFIG_INAME]		= mgmt_ipc_cfg_initiatorname,

[MGMT_IPC_CONFIG_IALIAS]	= mgmt_ipc_cfg_initiatoralias,

[MGMT_IPC_CONFIG_FILE]		= mgmt_ipc_cfg_filename,

[MGMT_IPC_IMMEDIATE_STOP]	= mgmt_ipc_immediate_stop,

[MGMT_IPC_NOTIFY_ADD_NODE]	= mgmt_ipc_notify_add_node,

[MGMT_IPC_NOTIFY_DEL_NODE]	= mgmt_ipc_notify_del_node,

[MGMT_IPC_NOTIFY_ADD_PORTAL]	= mgmt_ipc_notify_add_portal,

[MGMT_IPC_NOTIFY_DEL_PORTAL]	= mgmt_ipc_notify_del_portal,

};

void mgmt_ipc_handle(int accept_fd)

{

	unsigned int command;

	int fd, err;

	queue_task_t *qtask = NULL;

	mgmt_ipc_fn_t *handler = NULL;

	char user[PEERUSER_MAX];

	qtask = calloc(1, sizeof(queue_task_t));

	if (!qtask)

		return;

	if ((fd = accept(accept_fd, NULL, NULL)) < 0) {

		free(qtask);

		return;

	}

	qtask->allocated = 1;

	qtask->mgmt_ipc_fd = fd;

	if (!mgmt_peeruser(fd, user) || strncmp(user, "root", PEERUSER_MAX)) {

		err = ISCSI_ERR_ACCESS;

		goto err;

	}

	if (mgmt_ipc_read_req(qtask) < 0) {

		mgmt_ipc_destroy_queue_task(qtask);

		return;

	}

	command = qtask->req.command;

	qtask->rsp.command = command;

	if (0 <= command && command < __MGMT_IPC_MAX_COMMAND)

		handler = mgmt_ipc_functions[command];

	if (handler != NULL) {

		/* If the handler returns OK, this means it

		 * already sent the reply. */

		err = handler(qtask);

		if (err == ISCSI_SUCCESS)

			return;

	} else {

		log_error("unknown request: %s(%d) %u",

			  __FUNCTION__, __LINE__, command);

		err = ISCSI_ERR_INVALID_MGMT_REQ;

	}

err:

	/* This will send the response, close the

	 * connection and free the qtask */

	mgmt_ipc_write_rsp(qtask, err);

}