MaxScale/server/core/dbusers.c

/*
 * This file is distributed as part of the SkySQL Gateway.  It 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,
 * version 2.
 *
 * 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.
 *
 * Copyright SkySQL Ab 2013
 */

/**
 * @file dbusers.c  - Loading MySQL users from a MySQL backend server, this needs libmysqlclient.so and header files
 *
 * @verbatim
 * Revision History
 *
 * Date		Who			Description
 * 24/06/2013	Massimiliano Pinto	Initial implementation
 * 08/08/2013	Massimiliano Pinto	Fixed bug for invalid memory access in row[1]+1 when row[1] is ""
 * 06/02/2014	Massimiliano Pinto	Mysql user root selected based on configuration flag
 * 26/02/2014	Massimiliano Pinto	Addd: replace_mysql_users() routine may replace users' table based on a checksum
 *
 * @endverbatim
 */

#include <stdio.h>
#include <mysql.h>

#include <dcb.h>
#include <service.h>
#include <users.h>
#include <dbusers.h>
#include <skygw_utils.h>
#include <log_manager.h>
#include <secrets.h>

#define USERS_QUERY_NO_ROOT " WHERE user NOT IN ('root')"
#define LOAD_MYSQL_USERS_QUERY "SELECT user, password, concat(user,host,password) AS userdata FROM mysql.user"

#define MYSQL_USERS_COUNT "SELECT COUNT(1) AS nusers FROM mysql.user"

extern int lm_enabled_logfiles_bitmask;

static int getUsers(SERVICE *service, struct users *users);

/**
 * Load the user/passwd form mysql.user table into the service users' hashtable
 * environment.
 *
 * @param service   The current service
 * @return      -1 on any error or the number of users inserted (0 means no users at all)
 */
int 
load_mysql_users(SERVICE *service)
{
	return getUsers(service, service->users);
}

/**
 * Reload the user/passwd form mysql.user table into the service users' hashtable
 * environment.
 *
 * @param service   The current service
 * @return      -1 on any error or the number of users inserted (0 means no users at all)
 */
int 
reload_mysql_users(SERVICE *service)
{
int		i;
struct users	*newusers, *oldusers;

	if ((newusers = users_alloc()) == NULL)
		return 0;
	i = getUsers(service, newusers);
	spinlock_acquire(&service->spin);
	oldusers = service->users;
	service->users = newusers;
	spinlock_release(&service->spin);
	users_free(oldusers);

	return i;
}

/**
 * Replace the user/passwd form mysql.user table into the service users' hashtable
 * environment.
 * The replacement is succesful only if the users' table checksums differ
 *
 * @param service   The current service
 * @return      -1 on any error or the number of users inserted (0 means no users at all)
 */
int 
replace_mysql_users(SERVICE *service)
{
int		i;
struct users	*newusers, *oldusers;

	if ((newusers = users_alloc()) == NULL)
		return -1;

	i = getUsers(service, newusers);

	if (i <= 0)
		return i;

	spinlock_acquire(&service->spin);
	oldusers = service->users;

	if (memcmp(oldusers->cksum, newusers->cksum, SHA_DIGEST_LENGTH) == 0) {
		/* same data, nothing to do */
		LOGIF(LD, (skygw_log_write_flush(
			LOGFILE_DEBUG,
			"%lu [replace_mysql_users] users' tables not switched, checksum is the same",
			pthread_self())));
		/* free the new table */
		users_free(newusers);
		i = 0;
	} else {
		/* replace the service with effective new data */
		LOGIF(LD, (skygw_log_write_flush(
			LOGFILE_DEBUG,
			"%lu [replace_mysql_users] users' tables replaced, checksum differs",
			pthread_self())));
		service->users = newusers;
	}

	spinlock_release(&service->spin);

	if (i)
		users_free(oldusers);

	return i;
}

/**
 * Load the user/passwd form mysql.user table into the service users' hashtable
 * environment.
 *
 * @param service	The current service
 * @param users		The users table into which to load the users
 * @return      -1 on any error or the number of users inserted (0 means no users at all)
 */
static int
getUsers(SERVICE *service, struct users *users)
{
	MYSQL		*con = NULL;
	MYSQL_ROW	row;
	MYSQL_RES	*result = NULL;
	int		num_fields = 0;
	char		*service_user = NULL;
	char		*service_passwd = NULL;
	char		*dpwd;
	int		total_users = 0;
	SERVER		*server;
	char		*users_query; 
	unsigned char	hash[SHA_DIGEST_LENGTH]="";
	char		*users_data = NULL;
	int 		nusers = 0;
	int		users_data_row_len = MYSQL_USER_MAXLEN + MYSQL_HOST_MAXLEN + MYSQL_PASSWORD_LEN + 1;

	if(service->enable_root)
		users_query = LOAD_MYSQL_USERS_QUERY;
	else
		users_query = LOAD_MYSQL_USERS_QUERY USERS_QUERY_NO_ROOT;
	
	serviceGetUser(service, &service_user, &service_passwd);
	/** multi-thread environment requires that thread init succeeds. */
	if (mysql_thread_init()) {
		LOGIF(LE, (skygw_log_write_flush(
                        LOGFILE_ERROR,
                        "Error : mysql_thread_init failed.")));
		return -1;
	}
    
	con = mysql_init(NULL);

 	if (con == NULL) {
		LOGIF(LE, (skygw_log_write_flush(
                        LOGFILE_ERROR,
                        "Error : mysql_init: %s",
                        mysql_error(con))));
		return -1;
	}

	if (mysql_options(con, MYSQL_OPT_USE_REMOTE_CONNECTION, NULL)) {
		LOGIF(LE, (skygw_log_write_flush(
                        LOGFILE_ERROR,
                        "Error : failed to set external connection. "
                        "It is needed for backend server connections. "
                        "Exiting.")));
		return -1;
	}
	/*
	 * Attempt to connect to each database in the service in turn until
	 * we find one that we can connect to or until we run out of databases
	 * to try
	 */
	server = service->databases;
	dpwd = decryptPassword(service_passwd);
	while (server != NULL && mysql_real_connect(con,
                                                    server->name,
                                                    service_user,
                                                    dpwd,
                                                    NULL,
                                                    server->port,
                                                    NULL,
                                                    0) == NULL)
	{
                server = server->nextdb;
	}
	free(dpwd);
	if (server == NULL)
	{
		LOGIF(LE, (skygw_log_write_flush(
                        LOGFILE_ERROR,
                        "Error : Unable to get user data from backend database "
                        "for service %s. Missing server information.",
                        service->name)));
		mysql_close(con);
		return -1;
	}

	if (mysql_query(con, MYSQL_USERS_COUNT)) {
		LOGIF(LE, (skygw_log_write_flush(
                        LOGFILE_ERROR,
                        "Error : Loading users for service %s encountered "
                        "error: %s.",
                        service->name,
                        mysql_error(con))));
		mysql_close(con);
		return -1;
	}
	result = mysql_store_result(con);

	if (result == NULL) {
		LOGIF(LE, (skygw_log_write_flush(
                        LOGFILE_ERROR,
                        "Error : Loading users for service %s encountered "
                        "error: %s.",
                        service->name,
                        mysql_error(con))));
		mysql_close(con);
		return -1;
	}
	num_fields = mysql_num_fields(result);
	row = mysql_fetch_row(result);

	nusers = atoi(row[0]);

	mysql_free_result(result);

	if (!nusers) {
		LOGIF(LE, (skygw_log_write_flush(
                        LOGFILE_ERROR,
                        "Error : Counting users for service %s returned 0",
                        service->name)));
		mysql_close(con);
		return -1;
	}

	if (mysql_query(con, users_query)) {
		LOGIF(LE, (skygw_log_write_flush(
                        LOGFILE_ERROR,
                        "Error : Loading users for service %s encountered "
                        "error: %s.",
                        service->name,
                        mysql_error(con))));
		mysql_close(con);
		return -1;
	}

	result = mysql_store_result(con);
  
	if (result == NULL) {
		LOGIF(LE, (skygw_log_write_flush(
                        LOGFILE_ERROR,
                        "Error : Loading users for service %s encountered "
                        "error: %s.",
                        service->name,
                        mysql_error(con))));
		mysql_close(con);
		return -1;
	}
	num_fields = mysql_num_fields(result);
	
	users_data = (char *)calloc(nusers, users_data_row_len * sizeof(char));

	if(users_data == NULL)
		return -1;

	while ((row = mysql_fetch_row(result))) { 
		/**
                 * Two fields should be returned.
                 * user and passwd+1 (escaping the first byte that is '*') are
                 * added to hashtable.
                 */
		users_add(users, row[0], strlen(row[1]) ? row[1]+1 : row[1]);

		strncat(users_data, row[2], users_data_row_len);
		
		total_users++;
	}

        SHA1((const unsigned char *) users_data, strlen(users_data), hash);

	memcpy(users->cksum, hash, SHA_DIGEST_LENGTH);

	free(users_data);

	mysql_free_result(result);
	mysql_close(con);
	mysql_thread_end();

	return total_users;
}