/*
** Zabbix
** Copyright (C) 2001-2016 Zabbix SIA
**
** 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 "common.h"
#include "log.h"
#include "setproctitle.h"

/* scheduler support */

#define ZBX_SCHEDULER_FILTER_DAY	1
#define ZBX_SCHEDULER_FILTER_HOUR	2
#define ZBX_SCHEDULER_FILTER_MINUTE	3
#define ZBX_SCHEDULER_FILTER_SECOND	4

typedef struct zbx_scheduler_filter
{
	int				start;
	int				end;
	int				step;

	struct zbx_scheduler_filter	*next;
}
zbx_scheduler_filter_t;

typedef struct zbx_scheduler_interval
{
	zbx_scheduler_filter_t		*mdays;
	zbx_scheduler_filter_t		*wdays;
	zbx_scheduler_filter_t		*hours;
	zbx_scheduler_filter_t		*minutes;
	zbx_scheduler_filter_t		*seconds;

	int				filter_level;

	struct zbx_scheduler_interval	*next;
}
zbx_scheduler_interval_t;

ZBX_THREAD_LOCAL volatile sig_atomic_t	zbx_timed_out;	/* 0 - no timeout occurred, 1 - SIGALRM took place */

#ifdef _WINDOWS

char	ZABBIX_SERVICE_NAME[ZBX_SERVICE_NAME_LEN] = APPLICATION_NAME;
char	ZABBIX_EVENT_SOURCE[ZBX_SERVICE_NAME_LEN] = APPLICATION_NAME;

int	__zbx_stat(const char *path, zbx_stat_t *buf)
{
	int	ret, fd;
	wchar_t	*wpath;

	wpath = zbx_utf8_to_unicode(path);

	if (-1 == (ret = _wstat64(wpath, buf)))
		goto out;

	if (0 != S_ISDIR(buf->st_mode) || 0 != buf->st_size)
		goto out;

	/* In the case of symlinks _wstat64 returns zero file size.   */
	/* Try to work around it by opening the file and using fstat. */

	ret = -1;

	if (-1 != (fd = _wopen(wpath, O_RDONLY)))
	{
		ret = _fstat64(fd, buf);
		_close(fd);
	}
out:
	zbx_free(wpath);

	return ret;
}

#endif

/******************************************************************************
 *                                                                            *
 * Function: get_program_name                                                 *
 *                                                                            *
 * Purpose: return program name without path                                  *
 *                                                                            *
 * Parameters: path                                                           *
 *                                                                            *
 * Return value: program name without path                                    *
 *                                                                            *
 * Author: Eugene Grigorjev                                                   *
 *                                                                            *
 ******************************************************************************/
const char	*get_program_name(const char *path)
{
	const char	*filename = NULL;

	for (filename = path; path && *path; path++)
	{
		if ('\\' == *path || '/' == *path)
			filename = path + 1;
	}

	return filename;
}

/******************************************************************************
 *                                                                            *
 * Function: zbx_timespec                                                     *
 *                                                                            *
 * Purpose: Gets the current time.                                            *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 * Comments: Time in seconds since midnight (00:00:00),                       *
 *           January 1, 1970, coordinated universal time (UTC).               *
 *                                                                            *
 ******************************************************************************/
void	zbx_timespec(zbx_timespec_t *ts)
{
	static zbx_timespec_t	*last_ts = NULL;
	static int		corr = 0;
#ifdef _WINDOWS
	LARGE_INTEGER	tickPerSecond, tick;
	static int	boottime = 0;
	BOOL		rc = FALSE;
#else
	struct timeval	tv;
	int		rc = -1;
#	ifdef HAVE_TIME_CLOCK_GETTIME
	struct timespec	tp;
#	endif
#endif

	if (NULL == last_ts)
		last_ts = zbx_calloc(last_ts, 1, sizeof(zbx_timespec_t));

#ifdef _WINDOWS
	if (TRUE == (rc = QueryPerformanceFrequency(&tickPerSecond)))
	{
		if (TRUE == (rc = QueryPerformanceCounter(&tick)))
		{
			ts->ns = (int)(1000000000 * (tick.QuadPart % tickPerSecond.QuadPart) / tickPerSecond.QuadPart);

			tick.QuadPart = tick.QuadPart / tickPerSecond.QuadPart;

			if (0 == boottime)
				boottime = (int)(time(NULL) - tick.QuadPart);

			ts->sec = (int)(tick.QuadPart + boottime);
		}
	}

	if (TRUE != rc)
	{
		struct _timeb   tb;

		_ftime(&tb);

		ts->sec = (int)tb.time;
		ts->ns = tb.millitm * 1000000;
	}
#else	/* not _WINDOWS */
#ifdef HAVE_TIME_CLOCK_GETTIME
	if (0 == (rc = clock_gettime(CLOCK_REALTIME, &tp)))
	{
		ts->sec = (int)tp.tv_sec;
		ts->ns = (int)tp.tv_nsec;
	}
#endif	/* HAVE_TIME_CLOCK_GETTIME */

	if (0 != rc && 0 == (rc = gettimeofday(&tv, NULL)))
	{
		ts->sec = (int)tv.tv_sec;
		ts->ns = (int)tv.tv_usec * 1000;
	}

	if (0 != rc)
	{
		ts->sec = (int)time(NULL);
		ts->ns = 0;
	}
#endif	/* not _WINDOWS */

	if (last_ts->ns == ts->ns && last_ts->sec == ts->sec)
	{
		ts->ns += ++corr;

		while (ts->ns >= 1000000000)
		{
			ts->sec++;
			ts->ns -= 1000000000;
		}
	}
	else
	{
		last_ts->sec = ts->sec;
		last_ts->ns = ts->ns;
		corr = 0;
	}
}

/******************************************************************************
 *                                                                            *
 * Function: zbx_time                                                         *
 *                                                                            *
 * Purpose: Gets the current time.                                            *
 *                                                                            *
 * Return value: Time in seconds                                              *
 *                                                                            *
 * Author: Eugene Grigorjev                                                   *
 *                                                                            *
 * Comments: Time in seconds since midnight (00:00:00),                       *
 *           January 1, 1970, coordinated universal time (UTC).               *
 *                                                                            *
 ******************************************************************************/
double	zbx_time(void)
{
	zbx_timespec_t	ts;

	zbx_timespec(&ts);

	return (double)ts.sec + 1.0e-9 * (double)ts.ns;
}

/******************************************************************************
 *                                                                            *
 * Function: zbx_current_time                                                 *
 *                                                                            *
 * Purpose: Gets the current time including UTC offset                        *
 *                                                                            *
 * Return value: Time in seconds                                              *
 *                                                                            *
 * Author: Eugene Grigorjev                                                   *
 *                                                                            *
 ******************************************************************************/
double	zbx_current_time(void)
{
	return zbx_time() + ZBX_JAN_1970_IN_SEC;
}

/******************************************************************************
 *                                                                            *
 * Function: is_leap_year                                                     *
 *                                                                            *
 * Return value:  SUCCEED - year is a leap year                               *
 *                FAIL    - year is not a leap year                           *
 *                                                                            *
 ******************************************************************************/
static int	is_leap_year(int year)
{
	return 0 == year % 4 && (0 != year % 100 || 0 == year % 400) ? SUCCEED : FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: zbx_get_time                                                     *
 *                                                                            *
 * Purpose:                                                                   *
 *     get current time and store it in memory locations provided by caller   *
 *                                                                            *
 * Parameters:                                                                *
 *     tm           - [OUT] broken-down representation of the current time    *
 *     milliseconds - [OUT] milliseconds since the previous second            *
 *     tz           - [OUT] local time offset from UTC (optional)             *
 *                                                                            *
 * Comments:                                                                  *
 *     On Windows localtime() and gmtime() return pointers to static,         *
 *     thread-local storage locations. On Unix localtime() and gmtime() are   *
 *     not thread-safe and re-entrant as they return pointers to static       *
 *     storage locations which can be overwritten by localtime(), gmtime()    *
 *     or other time functions in other threads or signal handlers. To avoid  *
 *     this we use localtime_r() and gmtime_r().                              *
 *                                                                            *
 ******************************************************************************/
void	zbx_get_time(struct tm *tm, long *milliseconds, zbx_timezone_t *tz)
{
#ifdef _WINDOWS
	struct _timeb	current_time;

	_ftime(&current_time);
	*tm = *localtime(&current_time.time);	/* localtime() cannot return NULL if called with valid parameter */
	*milliseconds = current_time.millitm;
#else
	struct timeval	current_time;

	gettimeofday(&current_time, NULL);
	localtime_r(&current_time.tv_sec, tm);
	*milliseconds = current_time.tv_usec / 1000;
#endif
	if (NULL != tz)
	{
#ifdef HAVE_TM_TM_GMTOFF
#	define ZBX_UTC_OFF	tm->tm_gmtoff
#else
#	define ZBX_UTC_OFF	offset
		long		offset;
		struct tm	tm_utc;
#ifdef _WINDOWS
		tm_utc = *gmtime(&current_time.time);	/* gmtime() cannot return NULL if called with valid parameter */
#else
		gmtime_r(&current_time.tv_sec, &tm_utc);
#endif
		offset = (tm->tm_yday - tm_utc.tm_yday) * SEC_PER_DAY + (tm->tm_hour - tm_utc.tm_hour) * SEC_PER_HOUR +
				(tm->tm_min - tm_utc.tm_min) * SEC_PER_MIN;	/* assuming seconds are equal */

		while (tm->tm_year > tm_utc.tm_year)
			offset += (SUCCEED == is_leap_year(tm_utc.tm_year++) ? SEC_PER_YEAR + SEC_PER_DAY : SEC_PER_YEAR);

		while (tm->tm_year < tm_utc.tm_year)
			offset -= (SUCCEED == is_leap_year(--tm_utc.tm_year) ? SEC_PER_YEAR + SEC_PER_DAY : SEC_PER_YEAR);
#endif
		tz->tz_sign = (0 <= ZBX_UTC_OFF ? '+' : '-');
		tz->tz_hour = labs(ZBX_UTC_OFF) / SEC_PER_HOUR;
		tz->tz_min = (labs(ZBX_UTC_OFF) - tz->tz_hour * SEC_PER_HOUR) / SEC_PER_MIN;
		/* assuming no remaining seconds like in historic Asia/Riyadh87, Asia/Riyadh88 and Asia/Riyadh89 */
#undef ZBX_UTC_OFF
	}
}

/******************************************************************************
 *                                                                            *
 * Function: zbx_utc_time                                                     *
 *                                                                            *
 * Purpose: get UTC time from time from broken down time elements             *
 *                                                                            *
 * Parameters:                                                                *
 *     year  - [IN] year (1970-...)                                           *
 *     month - [IN] month (1-12)                                              *
 *     mday  - [IN] day of month (1-..., depending on month and year)         *
 *     hour  - [IN] hours (0-23)                                              *
 *     min   - [IN] minutes (0-59)                                            *
 *     sec   - [IN] seconds (0-61, leap seconds are not strictly validated)   *
 *     t     - [OUT] Epoch timestamp                                          *
 *                                                                            *
 * Return value:  SUCCEED - date is valid and resulting timestamp is positive *
 *                FAIL - otherwise                                            *
 *                                                                            *
 ******************************************************************************/
int	zbx_utc_time(int year, int mon, int mday, int hour, int min, int sec, int *t)
{
/* number of leap years before but not including year */
#define ZBX_LEAP_YEARS(year)	(((year) - 1) / 4 - ((year) - 1) / 100 + ((year) - 1) / 400)

	/* days since the beginning of non-leap year till the beginning of the month */
	static const int	month_day[12] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
	static const int	epoch_year = 1970;

	if (epoch_year <= year && 1 <= mon && mon <= 12 && 1 <= mday && mday <= zbx_day_in_month(year, mon) &&
			0 <= hour && hour <= 23 && 0 <= min && min <= 59 && 0 <= sec && sec <= 61 &&
			0 <= (*t = (year - epoch_year) * SEC_PER_YEAR +
			(ZBX_LEAP_YEARS(2 < mon ? year + 1 : year) - ZBX_LEAP_YEARS(epoch_year)) * SEC_PER_DAY +
			(month_day[mon - 1] + mday - 1) * SEC_PER_DAY + hour * SEC_PER_HOUR + min * SEC_PER_MIN + sec))
	{
		return SUCCEED;
	}

	return FAIL;
#undef ZBX_LEAP_YEARS
}

/******************************************************************************
 *                                                                            *
 * Function: zbx_day_in_month                                                 *
 *                                                                            *
 * Purpose: returns number of days in a month                                 *
 *                                                                            *
 * Parameters:                                                                *
 *     year  - [IN] year                                                      *
 *     mon   - [IN] month (1-12)                                              *
 *                                                                            *
 * Return value: 28-31 depending on number of days in the month, defaults to  *
 *               30 if the month is outside of allowed range                  *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 ******************************************************************************/
int	zbx_day_in_month(int year, int mon)
{
	/* number of days in the month of a non-leap year */
	static const unsigned char	month[12] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };

	if (1 <= mon && mon <= 12)	/* add one day in February of a leap year */
		return month[mon - 1] + (2 == mon && SUCCEED == is_leap_year(year) ? 1 : 0);

	return 30;
}

/******************************************************************************
 *                                                                            *
 * Function: zbx_calloc2                                                      *
 *                                                                            *
 * Purpose: allocates nmemb * size bytes of memory and fills it with zeros    *
 *                                                                            *
 * Return value: returns a pointer to the newly allocated memory              *
 *                                                                            *
 * Author: Eugene Grigorjev, Rudolfs Kreicbergs                               *
 *                                                                            *
 ******************************************************************************/
void    *zbx_calloc2(const char *filename, int line, void *old, size_t nmemb, size_t size)
{
	int	max_attempts;
	void	*ptr = NULL;

	/* old pointer must be NULL */
	if (NULL != old)
	{
		zabbix_log(LOG_LEVEL_CRIT, "[file:%s,line:%d] zbx_calloc: allocating already allocated memory. "
				"Please report this to Zabbix developers.",
				filename, line);
	}

	for (
		max_attempts = 10, nmemb = MAX(nmemb, 1), size = MAX(size, 1);
		0 < max_attempts && NULL == ptr;
		ptr = calloc(nmemb, size), max_attempts--
	);

	if (NULL != ptr)
		return ptr;

	zabbix_log(LOG_LEVEL_CRIT, "[file:%s,line:%d] zbx_calloc: out of memory. Requested " ZBX_FS_SIZE_T " bytes.",
			filename, line, (zbx_fs_size_t)size);

	exit(EXIT_FAILURE);
}

/******************************************************************************
 *                                                                            *
 * Function: zbx_malloc2                                                      *
 *                                                                            *
 * Purpose: allocates size bytes of memory                                    *
 *                                                                            *
 * Return value: returns a pointer to the newly allocated memory              *
 *                                                                            *
 * Author: Eugene Grigorjev                                                   *
 *                                                                            *
 ******************************************************************************/
void    *zbx_malloc2(const char *filename, int line, void *old, size_t size)
{
	int	max_attempts;
	void	*ptr = NULL;

	/* old pointer must be NULL */
	if (NULL != old)
	{
		zabbix_log(LOG_LEVEL_CRIT, "[file:%s,line:%d] zbx_malloc: allocating already allocated memory. "
				"Please report this to Zabbix developers.",
				filename, line);
	}

	for (
		max_attempts = 10, size = MAX(size, 1);
		0 < max_attempts && NULL == ptr;
		ptr = malloc(size), max_attempts--
	);

	if (NULL != ptr)
		return ptr;

	zabbix_log(LOG_LEVEL_CRIT, "[file:%s,line:%d] zbx_malloc: out of memory. Requested " ZBX_FS_SIZE_T " bytes.",
			filename, line, (zbx_fs_size_t)size);

	exit(EXIT_FAILURE);
}

/******************************************************************************
 *                                                                            *
 * Function: zbx_realloc2                                                     *
 *                                                                            *
 * Purpose: changes the size of the memory block pointed to by old            *
 *          to size bytes                                                     *
 *                                                                            *
 * Return value: returns a pointer to the newly allocated memory              *
 *                                                                            *
 * Author: Eugene Grigorjev                                                   *
 *                                                                            *
 ******************************************************************************/
void    *zbx_realloc2(const char *filename, int line, void *old, size_t size)
{
	int	max_attempts;
	void	*ptr = NULL;

	for (
		max_attempts = 10, size = MAX(size, 1);
		0 < max_attempts && NULL == ptr;
		ptr = realloc(old, size), max_attempts--
	);

	if (NULL != ptr)
		return ptr;

	zabbix_log(LOG_LEVEL_CRIT, "[file:%s,line:%d] zbx_realloc: out of memory. Requested " ZBX_FS_SIZE_T " bytes.",
			filename, line, (zbx_fs_size_t)size);

	exit(EXIT_FAILURE);
}

char    *zbx_strdup2(const char *filename, int line, char *old, const char *str)
{
	int	retry;
	char	*ptr = NULL;

	zbx_free(old);

	for (retry = 10; 0 < retry && NULL == ptr; ptr = strdup(str), retry--)
		;

	if (NULL != ptr)
		return ptr;

	zabbix_log(LOG_LEVEL_CRIT, "[file:%s,line:%d] zbx_strdup: out of memory. Requested " ZBX_FS_SIZE_T " bytes.",
			filename, line, (zbx_fs_size_t)(strlen(str) + 1));

	exit(EXIT_FAILURE);
}

/****************************************************************************************
 *                                                                                      *
 * Function: zbx_guaranteed_memset                                                      *
 *                                                                                      *
 * Purpose: For overwriting sensitive data in memory.                                   *
 *          Similar to memset() but should not be optimized out by a compiler.          *
 *                                                                                      *
 * Derived from:                                                                        *
 *   http://www.dwheeler.com/secure-programs/Secure-Programs-HOWTO/protect-secrets.html *
 * See also:                                                                            *
 *   http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1381.pdf on secure_memset()       *
 *                                                                                      *
 ****************************************************************************************/
void	*zbx_guaranteed_memset(void *v, int c, size_t n)
{
	volatile signed char	*p = (volatile signed char *)v;

	while (0 != n--)
		*p++ = (signed char)c;

	return v;
}

/******************************************************************************
 *                                                                            *
 * Function: __zbx_zbx_setproctitle                                           *
 *                                                                            *
 * Purpose: set process title                                                 *
 *                                                                            *
 * Author: Eugene Grigorjev                                                   *
 *                                                                            *
 ******************************************************************************/
void	__zbx_zbx_setproctitle(const char *fmt, ...)
{
#if defined(HAVE_FUNCTION_SETPROCTITLE) || defined(PS_OVERWRITE_ARGV) || defined(PS_PSTAT_ARGV)
	const char	*__function_name = "__zbx_zbx_setproctitle";
	char		title[MAX_STRING_LEN];
	va_list		args;

	va_start(args, fmt);
	zbx_vsnprintf(title, sizeof(title), fmt, args);
	va_end(args);

	zabbix_log(LOG_LEVEL_DEBUG, "%s() title:'%s'", __function_name, title);
#endif

#if defined(HAVE_FUNCTION_SETPROCTITLE)
	setproctitle("%s", title);
#elif defined(PS_OVERWRITE_ARGV) || defined(PS_PSTAT_ARGV)
	setproctitle_set_status(title);
#endif
}

/******************************************************************************
 *                                                                            *
 * Function: check_time_period                                                *
 *                                                                            *
 * Purpose: check if current time is within given period                      *
 *                                                                            *
 * Parameters: period - time period in format [d1-d2,hh:mm-hh:mm]*            *
 *             now    - timestamp for comparison                              *
 *                      if NULL - use current timestamp.                      *
 *                                                                            *
 * Return value: FAIL - out of period, SUCCEED - within the period            *
 *                                                                            *
 * Author: Alexei Vladishev                                                   *
 *                                                                            *
 * Comments:   !!! Don't forget to sync code with PHP !!!                     *
 *                                                                            *
 ******************************************************************************/
int	check_time_period(const char *period, time_t now)
{
	const char	*__function_name = "check_time_period";
	const char	*s, *delim;
	int		d1, d2, h1, h2, m1, m2, flag, day, sec, sec1, sec2, ret = FAIL;
	struct tm	*tm;

	zabbix_log(LOG_LEVEL_DEBUG, "In %s() period:'%s'", __function_name, period);

	if ((time_t)0 == now)
		now = time(NULL);

	tm = localtime(&now);
	day = 0 == tm->tm_wday ? 7 : tm->tm_wday;
	sec = SEC_PER_HOUR * tm->tm_hour + SEC_PER_MIN * tm->tm_min + tm->tm_sec;

	zabbix_log(LOG_LEVEL_DEBUG, "%d,%d:%d", day, (int)tm->tm_hour, (int)tm->tm_min);

	for (s = period; '\0' != *s;)
	{
		delim = strchr(s, ';');

		zabbix_log(LOG_LEVEL_DEBUG, "period [%s]", s);

		flag = (6 == sscanf(s, "%d-%d,%d:%d-%d:%d", &d1, &d2, &h1, &m1, &h2, &m2));

		if (0 == flag)
		{
			flag = (5 == sscanf(s, "%d,%d:%d-%d:%d", &d1, &h1, &m1, &h2, &m2));
			d2 = d1;
		}

		if (0 != flag)
		{
			zabbix_log(LOG_LEVEL_DEBUG, "%d-%d,%d:%d-%d:%d", d1, d2, h1, m1, h2, m2);

			sec1 = SEC_PER_HOUR * h1 + SEC_PER_MIN * m1;
			sec2 = SEC_PER_HOUR * h2 + SEC_PER_MIN * m2;	/* do not include upper bound */

			if (d1 <= day && day <= d2 && sec1 <= sec && sec < sec2)
			{
				ret = SUCCEED;
				break;
			}
		}
		else
			zabbix_log(LOG_LEVEL_ERR, "wrong time period format [%s]", period);

		if (NULL != delim)
			s = delim + 1;
		else
			break;
	}

	zabbix_log(LOG_LEVEL_DEBUG, "End of %s():%s", __function_name, zbx_result_string(ret));

	return ret;
}

/******************************************************************************
 *                                                                            *
 * Function: get_current_delay                                                *
 *                                                                            *
 * Purpose: return delay value that is currently applicable                   *
 *                                                                            *
 * Parameters: delay - [IN] default delay value, can be overridden            *
 *             flex_intervals - [IN] descriptions of flexible intervals       *
 *                                   in the form [dd/d1-d2,hh:mm-hh:mm;]      *
 *             now - [IN] current time                                        *
 *                                                                            *
 * Return value: delay value - either default or minimum delay value          *
 *                             out of all applicable intervals                *
 *                                                                            *
 * Author: Alexei Vladishev, Alexander Vladishev, Aleksandrs Saveljevs        *
 *                                                                            *
 ******************************************************************************/
static int	get_current_delay(int delay, const char *flex_intervals, time_t now)
{
	const char	*s, *delim;
	char		flex_period[30];
	int		flex_delay, current_delay = -1;

	if (NULL == flex_intervals || '\0' == *flex_intervals)
		return delay;

	for (s = flex_intervals; '\0' != *s; s = delim + 1)
	{
		delim = strchr(s, ';');

		zabbix_log(LOG_LEVEL_DEBUG, "delay period [%s]", s);

		if (2 == sscanf(s, "%d/%29[^;]s", &flex_delay, flex_period))
		{
			zabbix_log(LOG_LEVEL_DEBUG, "%d sec at %s", flex_delay, flex_period);

			if ((-1 == current_delay || flex_delay < current_delay) &&
					SUCCEED == check_time_period(flex_period, now))
			{
				current_delay = flex_delay;
			}
		}
		else
			zabbix_log(LOG_LEVEL_ERR, "wrong delay period format: \"%s\"", s);

		if (NULL == delim)
			break;
	}

	if (-1 == current_delay)
		return delay;

	return current_delay;
}

/******************************************************************************
 *                                                                            *
 * Function: get_next_delay_interval                                          *
 *                                                                            *
 * Purpose: return time when next delay settings take effect                  *
 *                                                                            *
 * Parameters: flex_intervals - [IN] descriptions of flexible intervals       *
 *                                   in the form [dd/d1-d2,hh:mm-hh:mm;]      *
 *             now = [IN] current time                                        *
 *             next_interval = [OUT] start of next delay interval             *
 *                                                                            *
 * Return value: SUCCEED - there is a next interval                           *
 *               FAIL - otherwise (in this case, next_interval is unaffected) *
 *                                                                            *
 * Author: Alexei Vladishev, Alexander Vladishev, Aleksandrs Saveljevs        *
 *                                                                            *
 ******************************************************************************/
static int	get_next_delay_interval(const char *flex_intervals, time_t now, time_t *next_interval)
{
	const char	*s, *delim;
	struct tm	*tm;
	int		day, sec, sec1, sec2, delay, d1, d2, h1, h2, m1, m2, flag;
	time_t		next = 0;

	if (NULL == flex_intervals || '\0' == *flex_intervals)
		return FAIL;

	tm = localtime(&now);
	day = 0 == tm->tm_wday ? 7 : tm->tm_wday;
	sec = SEC_PER_HOUR * tm->tm_hour + SEC_PER_MIN * tm->tm_min + tm->tm_sec;

	for (s = flex_intervals; '\0' != *s;)
	{
		delim = strchr(s, ';');

		zabbix_log(LOG_LEVEL_DEBUG, "delay period [%s]", s);

		flag = (7 == sscanf(s, "%d/%d-%d,%d:%d-%d:%d", &delay, &d1, &d2, &h1, &m1, &h2, &m2));

		if (0 == flag)
		{
			flag = (6 == sscanf(s, "%d/%d,%d:%d-%d:%d", &delay, &d1, &h1, &m1, &h2, &m2));
			d2 = d1;
		}

		if (0 != flag)
		{
			zabbix_log(LOG_LEVEL_DEBUG, "%d/%d-%d,%d:%d-%d:%d", delay, d1, d2, h1, m1, h2, m2);

			sec1 = SEC_PER_HOUR * h1 + SEC_PER_MIN * m1;
			sec2 = SEC_PER_HOUR * h2 + SEC_PER_MIN * m2;	/* do not include upper bound */

			if (d1 <= day && day <= d2 && sec1 <= sec && sec < sec2)	/* current period */
			{
				if (0 == next || next > now - sec + sec2)
					next = now - sec + sec2;	/* the next second after the */
									/* current interval's upper bound */
			}
			else if (d1 <= day && day <= d2 && sec < sec1)			/* will be active today */
			{
				if (0 == next || next > now - sec + sec1)
					next = now - sec + sec1;
			}
			else
			{
				int	next_day;

				next_day = (7 >= day + 1 ? day + 1 : 1);

				if (d1 <= next_day && next_day <= d2)			/* will be active tomorrow */
				{
					if (0 == next || next > now - sec + SEC_PER_DAY + sec1)
						next = now - sec + SEC_PER_DAY + sec1;
				}
				else							/* later in the future */
				{
					int	day_diff = -1;

					if (day < d1)
						day_diff = d1 - day;
					if (day >= d2)
						day_diff = (d1 + 7) - day;
					if (d1 <= day && day < d2)
					{
						/* should never happen */
						zabbix_log(LOG_LEVEL_ERR, "could not deduce day difference"
								" [%s, day=%d, time=%02d:%02d:%02d]",
								s, day, tm->tm_hour, tm->tm_min, tm->tm_sec);
						day_diff = -1;
					}

					if (-1 != day_diff &&
							(0 == next || next > now - sec + SEC_PER_DAY * day_diff + sec1))
						next = now - sec + SEC_PER_DAY * day_diff + sec1;
				}
			}
		}
		else
			zabbix_log(LOG_LEVEL_ERR, "wrong delay period format: \"%s\"", s);

		if (NULL != delim)
			s = delim + 1;
		else
			break;
	}

	if (0 != next && NULL != next_interval)
		*next_interval = next;

	return 0 != next ? SUCCEED : FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_filter_free                                            *
 *                                                                            *
 * Purpose: frees scheduler interval filter                                   *
 *                                                                            *
 * Parameters: filter - [IN] scheduler interval filter                        *
 *                                                                            *
 ******************************************************************************/
static void	scheduler_filter_free(zbx_scheduler_filter_t *filter)
{
	zbx_scheduler_filter_t	*filter_next;

	for (; NULL != filter; filter = filter_next)
	{
		filter_next = filter->next;
		zbx_free(filter);
	}
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_interval_free                                          *
 *                                                                            *
 * Purpose: frees scheduler interval                                          *
 *                                                                            *
 * Parameters: filter - [IN] scheduler interval                               *
 *                                                                            *
 ******************************************************************************/
static void	scheduler_interval_free(zbx_scheduler_interval_t *interval)
{
	zbx_scheduler_interval_t	*interval_next;

	for (; NULL != interval; interval = interval_next)
	{
		interval_next = interval->next;

		scheduler_filter_free(interval->mdays);
		scheduler_filter_free(interval->wdays);
		scheduler_filter_free(interval->hours);
		scheduler_filter_free(interval->minutes);
		scheduler_filter_free(interval->seconds);

		zbx_free(interval);
	}
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_parse_filter_r                                         *
 *                                                                            *
 * Purpose: parses text string into scheduler filter                          *
 *                                                                            *
 * Parameters: filter  - [IN/OUT] the first filter                            *
 *             text    - [IN] the text to parse                               *
 *             len     - [IN/OUT] the number of characters left to parse      *
 *             min     - [IN] the minimal time unit value                     *
 *             max     - [IN] the maximal time unit value                     *
 *             var_len - [IN] the maximum number of characters for a filter   *
 *                       variable (<from>, <to>, <step>)                      *
 *                                                                            *
 * Return value: SUCCEED - the fitler was successfully parsed                 *
 *               FAIL    - otherwise                                          *
 *                                                                            *
 * Comments: This function recursively calls itself for each filter fragment. *
 *                                                                            *
 ******************************************************************************/
static int	scheduler_parse_filter_r(zbx_scheduler_filter_t **filter, const char *text, int *len, int min, int max,
		int var_len)
{
	int			start = 0, end = 0, step = 1;
	const char		*pstart, *pend;
	zbx_scheduler_filter_t	*filter_new;

	pstart = pend = text;
	while (0 != isdigit(*pend) && 0 < *len)
	{
		pend++;
		(*len)--;
	}

	if (pend != pstart)
	{
		if (pend - pstart > var_len)
			return FAIL;

		if (SUCCEED != is_uint_n_range(pstart, pend - pstart, &start, sizeof(start), min, max))
			return FAIL;

		if ('-' == *pend)
		{
			pstart = pend + 1;

			do
			{
				pend++;
				(*len)--;
			}
			while (0 != isdigit(*pend) && 0 < *len);

			/* empty or too long value, fail */
			if (pend == pstart || pend - pstart > var_len)
				return FAIL;

			if (SUCCEED != is_uint_n_range(pstart, pend - pstart, &end, sizeof(end), min, max))
				return FAIL;

			if (end < start)
				return FAIL;
		}
		else
		{
			/* step is valid only for defined range */
			if ('/' == *pend)
				return FAIL;

			end = start;
		}
	}
	else
	{
		start = min;
		end = max;
	}

	if ('/' == *pend)
	{
		pstart = pend + 1;

		do
		{
			pend++;
			(*len)--;
		}
		while (0 != isdigit(*pend) && 0 < *len);

		/* empty or too long step, fail */
		if (pend == pstart || pend - pstart > var_len)
			return FAIL;

		if (SUCCEED != is_uint_n_range(pstart, pend - pstart, &step, sizeof(step), 1, end - start))
			return FAIL;
	}
	else
	{
		if (pend == text)
			return FAIL;
	}

	if (',' == *pend)
	{
		/* no next filter after ',' */
		if (0 == --(*len))
			return FAIL;

		pend++;

		if (SUCCEED != scheduler_parse_filter_r(filter, pend, len, min, max, var_len))
			return FAIL;
	}

	filter_new = zbx_malloc(NULL, sizeof(zbx_scheduler_filter_t));
	filter_new->start = start;
	filter_new->end = end;
	filter_new->step = step;
	filter_new->next = *filter;
	*filter = filter_new;

	return SUCCEED;
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_parse_filter                                           *
 *                                                                            *
 * Purpose: parses text string into scheduler filter                          *
 *                                                                            *
 * Parameters: filter  - [IN/OUT] the first filter                            *
 *             text    - [IN] the text to parse                               *
 *             len     - [IN/OUT] the number of characters left to parse      *
 *             min     - [IN] the minimal time unit value                     *
 *             max     - [IN] the maximal time unit value                     *
 *             var_len - [IN] the maximum number of characters for a filter   *
 *                       variable (<from>, <to>, <step>)                      *
 *                                                                            *
 * Return value: SUCCEED - the fitler was successfully parsed                 *
 *               FAIL    - otherwise                                          *
 *                                                                            *
 * Comments: This function will fail if a filter already exists. This         *
 *           user from defining multiple filters of the same time unit in a   *
 *           single interval. For example: h0h12 is invalid filter and its    *
 *           parsing must fail.                                               *
 *                                                                            *
 ******************************************************************************/
static int	scheduler_parse_filter(zbx_scheduler_filter_t **filter, const char *text, int *len, int min, int max,
		int var_len)
{
	if (NULL != *filter)
		return FAIL;

	return scheduler_parse_filter_r(filter, text, len, min, max, var_len);
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_interval_parse                                         *
 *                                                                            *
 * Purpose: parses scheduler interval                                         *
 *                                                                            *
 * Parameters: interval - [IN/OUT] the first interval                         *
 *             text     - [IN] the text to parse                              *
 *             len      - [IN] the text length                                *
 *                                                                            *
 * Return value: SUCCEED - the interval was successfully parsed               *
 *               FAIL    - otherwise                                          *
 *                                                                            *
 ******************************************************************************/
static int	scheduler_interval_parse(zbx_scheduler_interval_t *interval, const char *text, int len)
{
	int	ret = SUCCEED;

	if (0 == len)
		return FAIL;

	while (SUCCEED == ret && 0 != len)
	{
		int	old_len = len--;

		switch (*text)
		{
			case '\0':
				return FAIL;
			case 'h':
				if (ZBX_SCHEDULER_FILTER_HOUR < interval->filter_level)
					return FAIL;

				ret = scheduler_parse_filter(&interval->hours, text + 1, &len, 0, 23, 2);
				interval->filter_level = ZBX_SCHEDULER_FILTER_HOUR;

				break;
			case 's':
				if (ZBX_SCHEDULER_FILTER_SECOND < interval->filter_level)
					return FAIL;

				ret = scheduler_parse_filter(&interval->seconds, text + 1, &len, 0, 59, 2);
				interval->filter_level = ZBX_SCHEDULER_FILTER_SECOND;

				break;
			case 'w':
				if ('d' != text[1])
					return FAIL;

				if (ZBX_SCHEDULER_FILTER_DAY < interval->filter_level)
					return FAIL;

				len--;
				ret = scheduler_parse_filter(&interval->wdays, text + 2, &len, 1, 7, 1);
				interval->filter_level = ZBX_SCHEDULER_FILTER_DAY;

				break;
			case 'm':
				if ('d' == text[1])
				{
					if (ZBX_SCHEDULER_FILTER_DAY < interval->filter_level ||
							NULL != interval->wdays)
					{
						return FAIL;
					}

					len--;
					ret = scheduler_parse_filter(&interval->mdays, text + 2, &len, 1, 31, 2);
					interval->filter_level = ZBX_SCHEDULER_FILTER_DAY;
				}
				else
				{
					if (ZBX_SCHEDULER_FILTER_MINUTE < interval->filter_level)
						return FAIL;

					ret = scheduler_parse_filter(&interval->minutes, text + 1, &len, 0, 59, 2);
					interval->filter_level = ZBX_SCHEDULER_FILTER_MINUTE;
				}

				break;
			default:
				return FAIL;
		}

		text += old_len - len;
	}

	return ret;
}

/******************************************************************************
 *                                                                            *
 * Function: preprocess_flexible_interval                                     *
 *                                                                            *
 * Purpose: parses out the flexible interval in a text format and scheduler   *
 *          interval in zbx_scheduler_interval_t structure                    *
 *                                                                            *
 * Parameters: text       - [IN] the text to parse                            *
 *             interval   - [OUT] the parsed scheduler interval. Must be a    *
 *                          pointer to a NULL pointer on the first call. It   *
 *                          will be left untouched if the text does not       *
 *                          contain scheduler intervals                       *
 *             out        - [IN/OUT] flexible interval in text format         *
 *             out_alloc  - [IN/OUT] the number of bytes allocated for out    *
 *             out_offset - [IN/OUT] the flexible interval length in out      *
 *                          buffer                                            *
 *                                                                            *
 * Return value: SUCCEED - the text was successfully parsed                   *
 *               FAIL    - otherwise                                          *
 *                                                                            *
 * Comments: This function recursively calls itself for each interval.        *
 *                                                                            *
 ******************************************************************************/
static int	preprocess_flexible_interval(const char *text, zbx_scheduler_interval_t **interval,
		char **out, size_t *out_alloc, size_t *out_offset, char **errmsg)
{
	const char			*ptr;
	zbx_scheduler_interval_t	*new_interval;

	ptr = strchr(text, ';');

	if (NULL == ptr)
		ptr = text + strlen(text);

	if (0 != isdigit(*text))
	{
		if (0 != *out_offset)
			zbx_chrcpy_alloc(out, out_alloc, out_offset, ';');

		zbx_strncpy_alloc(out, out_alloc, out_offset, text, ptr - text);
	}

	if ('\0' != *ptr)
	{
		if (SUCCEED != preprocess_flexible_interval(ptr + 1, interval, out, out_alloc, out_offset, errmsg))
			return FAIL;
	}

	/* flexible interval has already been copied, return success */
	if (0 != isdigit(*text))
		return SUCCEED;

	new_interval = zbx_malloc(NULL, sizeof(zbx_scheduler_interval_t));
	memset(new_interval, 0, sizeof(zbx_scheduler_interval_t));

	if (SUCCEED != scheduler_interval_parse(new_interval, text, ptr - text))
	{
		size_t	errmsg_alloc = 0, errmsg_offset = 0;

		zbx_free(*errmsg);
		zbx_strcpy_alloc(errmsg, &errmsg_alloc, &errmsg_offset, "invalid scheduling interval: \"");
		zbx_strncpy_alloc(errmsg, &errmsg_alloc, &errmsg_offset, text, ptr - text + 1);
		zbx_strcpy_alloc(errmsg, &errmsg_alloc, &errmsg_offset, "\"");

		scheduler_interval_free(new_interval);
		return FAIL;
	}

	new_interval->next = *interval;
	*interval = new_interval;

	return SUCCEED;
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_get_nearest_filter_value                               *
 *                                                                            *
 * Purpose: gets the next nearest value that satisfies the filter chain       *
 *                                                                            *
 * Parameters: filter - [IN] the filter chain                                 *
 *             value  - [IN] the current value                                *
 *                      [OUT] the next nearest value (>= than input value)    *
 *                                                                            *
 * Return value: SUCCEED - the next nearest value was successfully found      *
 *               FAIL    - otherwise                                          *
 *                                                                            *
 ******************************************************************************/
static int	scheduler_get_nearest_filter_value(const zbx_scheduler_filter_t *filter, int *value)
{
	const zbx_scheduler_filter_t	*filter_next = NULL;

	for (; NULL != filter; filter = filter->next)
	{
		/* find matching filter */
		if (filter->start <= *value && *value <= filter->end)
		{
			int	next = *value, offset;

			/* apply step */
			offset = (next - filter->start) % filter->step;
			if (0 != offset)
				next += filter->step - offset;

			/* succeed if the calculated value is still in filter range */
			if (next <= filter->end)
			{
				*value = next;
				return SUCCEED;
			}
		}

		/* find the next nearest filter */
		if (filter->start > *value && (NULL == filter_next || filter_next->start > filter->start))
			filter_next = filter;
	}

	/* The value is not in a range of any filters, but we have next nearest filter. */
	if (NULL != filter_next)
	{
		*value = filter_next->start;
		return SUCCEED;
	}

	return FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_get_wday_nextcheck                                     *
 *                                                                            *
 * Purpose: calculates the next day that satisfies the week day filter        *
 *                                                                            *
 * Parameters: interval - [IN] the scheduler interval                         *
 *             tm       - [IN/OUT] the input/output date & time               *
 *                                                                            *
 * Return value: SUCCEED - the next day was found                             *
 *               FAIL    - the next day satisfying week day filter was not    *
 *                         found in the current month                         *
 *                                                                            *
 ******************************************************************************/
static int	scheduler_get_wday_nextcheck(const zbx_scheduler_interval_t *interval, struct tm *tm)
{
	int	value_now, value_next;

	if (NULL == interval->wdays)
		return SUCCEED;

	value_now = value_next = (0 == tm->tm_wday ? 7 : tm->tm_wday);

	/* get the nearest week day from the current week day*/
	if (SUCCEED != scheduler_get_nearest_filter_value(interval->wdays, &value_next))
	{
		/* in the case of failure move month day to the next week, reset week day and try again */
		tm->tm_mday += 7 - value_now + 1;
		value_now = value_next = 1;

		if (SUCCEED != scheduler_get_nearest_filter_value(interval->wdays, &value_next))
		{
			/* a valid week day filter must always match some day of a new week */
			THIS_SHOULD_NEVER_HAPPEN;
			return FAIL;
		}
	}

	/* adjust the month day by the week day offset */
	tm->tm_mday += value_next - value_now;

	/* check if the resulting month day is valid */
	return (-1 != mktime(tm) ? SUCCEED : FAIL);
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_validate_wday_filter                                   *
 *                                                                            *
 * Purpose: checks if the specified date satisfies week day filter            *
 *                                                                            *
 * Parameters: interval - [IN] the scheduler interval                         *
 *             tm       - [IN] the date & time to validate                    *
 *                                                                            *
 * Return value: SUCCEED - the input date satisfies week day filter           *
 *               FAIL    - otherwise                                          *
 *                                                                            *
 ******************************************************************************/
static int	scheduler_validate_wday_filter(const zbx_scheduler_interval_t *interval, struct tm *tm)
{
	time_t				nextcheck;
	const zbx_scheduler_filter_t	*filter;
	int				value;

	if (NULL == interval->wdays)
		return SUCCEED;

	/* mktime will aso set correct wday value */
	if (-1 == (nextcheck = mktime(tm)))
		return FAIL;

	value = (0 == tm->tm_wday ? 7 : tm->tm_wday);

	/* check if the value match week day filter */
	for (filter = interval->wdays; NULL != filter; filter = filter->next)
	{
		if (filter->start <= value && value <= filter->end)
		{
			int	next = value, offset;

			/* apply step */
			offset = (next - filter->start) % filter->step;
			if (0 != offset)
				next += filter->step - offset;

			/* succeed if the calculated value is still in filter range */
			if (next <= filter->end)
				return SUCCEED;
		}
	}

	return FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_get_day_nextcheck                                      *
 *                                                                            *
 * Purpose: calculates the next day that satisfies month and week day filters *
 *                                                                            *
 * Parameters: interval - [IN] the scheduler interval                         *
 *             tm       - [IN/OUT] the input/output date & time               *
 *                                                                            *
 * Return value: SUCCEED - the next day was found                             *
 *               FAIL    - the next day satisfying day filters was not        *
 *                         found in the current month                         *
 *                                                                            *
 ******************************************************************************/
static int	scheduler_get_day_nextcheck(const zbx_scheduler_interval_t *interval, struct tm *tm)
{
	/* first check if the provided tm structure has valid date format */
	if (-1 == mktime(tm))
		return FAIL;

	if (NULL == interval->mdays)
		return scheduler_get_wday_nextcheck(interval, tm);

	/* iterate through month days until week day filter matches or we have ran out of month days */
	while (SUCCEED == scheduler_get_nearest_filter_value(interval->mdays, &tm->tm_mday))
	{
		if (SUCCEED == scheduler_validate_wday_filter(interval, tm))
			return SUCCEED;

		tm->tm_mday++;

		/* check if the date is still valid - we haven't ran out of month days */
		if (-1 == mktime(tm))
			break;
	}

	return FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_get_filter_nextcheck                                   *
 *                                                                            *
 * Purpose: calculates the time/day that satisfies the specified filter       *
 *                                                                            *
 * Parameters: interval - [IN] the scheduler interval                         *
 *             level    - [IN] the filter level, see ZBX_SCHEDULER_FILTER_*   *
 *                        defines                                             *
 *             tm       - [IN/OUT] the input/output date & time               *
 *                                                                            *
 * Return value: SUCCEED - the next time/day was found                        *
 *               FAIL    - the next time/day was not found on the current     *
 *                         filter level                                       *
 *                                                                            *
 ******************************************************************************/
static int	scheduler_get_filter_nextcheck(const zbx_scheduler_interval_t *interval, int level, struct tm *tm)
{
	const zbx_scheduler_filter_t	*filter;
	int				max, *value;

	/* initialize data depending on filter level */
	switch (level)
	{
		case ZBX_SCHEDULER_FILTER_DAY:
			return scheduler_get_day_nextcheck(interval, tm);
		case ZBX_SCHEDULER_FILTER_HOUR:
			max = 23;
			filter = interval->hours;
			value = &tm->tm_hour;
			break;
		case ZBX_SCHEDULER_FILTER_MINUTE:
			max = 59;
			filter = interval->minutes;
			value = &tm->tm_min;
			break;
		case ZBX_SCHEDULER_FILTER_SECOND:
			max = 59;
			filter = interval->seconds;
			value = &tm->tm_sec;
			break;
		default:
			THIS_SHOULD_NEVER_HAPPEN;
			return FAIL;
	}

	if (max < *value)
		return FAIL;

	/* handle unspecified (default) filter */
	if (NULL == filter)
	{
		/* Empty filter matches all valid values if the filter level is less than        */
		/* interval filter level. For example if interval filter level is minutes - m30, */
		/* then hour filter matches all hours.                                           */
		if (interval->filter_level > level)
			return SUCCEED;

		/* If the filter level is greater than interval filter level, then filter       */
		/* matches only 0 value. For example if interval filter level is minutes - m30, */
		/* then seconds filter matches the 0th second.                                  */
		return 0 == *value ? SUCCEED : FAIL;
	}

	return scheduler_get_nearest_filter_value(filter, value);
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_apply_day_filter                                       *
 *                                                                            *
 * Purpose: applies day filter to the specified time/day calculating the next *
 *          scheduled check                                                   *
 *                                                                            *
 * Parameters: interval - [IN] the scheduler interval                         *
 *             tm       - [IN/OUT] the input/output date & time               *
 *                                                                            *
 ******************************************************************************/
static void	scheduler_apply_day_filter(zbx_scheduler_interval_t *interval, struct tm *tm)
{
	int	day = tm->tm_mday, mon = tm->tm_mon, year = tm->tm_year;

	while (SUCCEED != scheduler_get_filter_nextcheck(interval, ZBX_SCHEDULER_FILTER_DAY, tm))
	{
		if (11 < ++tm->tm_mon)
		{
			tm->tm_mon = 0;
			tm->tm_year++;
		}

		tm->tm_mday = 1;
	}

	/* reset hours, minutes and seconds if the day has been changed */
	if (tm->tm_mday != day || tm->tm_mon != mon || tm->tm_year != year)
	{
		tm->tm_hour = 0;
		tm->tm_min = 0;
		tm->tm_sec = 0;
	}
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_apply_hour_filter                                      *
 *                                                                            *
 * Purpose: applies hour filter to the specified time/day calculating the     *
 *          next scheduled check                                              *
 *                                                                            *
 * Parameters: interval - [IN] the scheduler interval                         *
 *             tm       - [IN/OUT] the input/output date & time               *
 *                                                                            *
 ******************************************************************************/
static void	scheduler_apply_hour_filter(zbx_scheduler_interval_t *interval, struct tm *tm)
{
	int	hour = tm->tm_hour;

	while (SUCCEED != scheduler_get_filter_nextcheck(interval, ZBX_SCHEDULER_FILTER_HOUR, tm))
	{
		tm->tm_mday++;
		tm->tm_hour = 0;

		/* day has been changed, we have to reapply day filter */
		scheduler_apply_day_filter(interval, tm);
	}

	/* reset minutes and seconds if hours has been changed */
	if (tm->tm_hour != hour)
	{
		tm->tm_min = 0;
		tm->tm_sec = 0;
	}
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_apply_minute_filter                                    *
 *                                                                            *
 * Purpose: applies minute filter to the specified time/day calculating the   *
 *          next scheduled check                                              *
 *                                                                            *
 * Parameters: interval - [IN] the scheduler interval                         *
 *             tm       - [IN/OUT] the input/output date & time               *
 *                                                                            *
 ******************************************************************************/
static void	scheduler_apply_minute_filter(zbx_scheduler_interval_t *interval, struct tm *tm)
{
	int	min = tm->tm_min;

	while (SUCCEED != scheduler_get_filter_nextcheck(interval, ZBX_SCHEDULER_FILTER_MINUTE, tm))
	{
		tm->tm_hour++;
		tm->tm_min = 0;

		/* hours have been changed, we have to reapply hour filter */
		scheduler_apply_hour_filter(interval, tm);
	}

	/* reset seconds if minutes has been changed */
	if (tm->tm_min != min)
		tm->tm_sec = 0;
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_apply_second_filter                                    *
 *                                                                            *
 * Purpose: applies second filter to the specified time/day calculating the   *
 *          next scheduled check                                              *
 *                                                                            *
 * Parameters: interval - [IN] the scheduler interval                         *
 *             tm       - [IN/OUT] the input/output date & time               *
 *                                                                            *
 ******************************************************************************/
static void	scheduler_apply_second_filter(zbx_scheduler_interval_t *interval, struct tm *tm)
{
	while (SUCCEED != scheduler_get_filter_nextcheck(interval, ZBX_SCHEDULER_FILTER_SECOND, tm))
	{
		tm->tm_min++;
		tm->tm_sec = 0;

		/* minutes have been changed, we have to reapply minute filter */
		scheduler_apply_minute_filter(interval, tm);
	}
}

/******************************************************************************
 *                                                                            *
 * Function: scheduler_get_nextcheck                                          *
 *                                                                            *
 * Purpose: applies second filter to the specified time/day calculating the   *
 *          next scheduled check                                              *
 *                                                                            *
 * Parameters: interval - [IN] the scheduler interval                         *
 *             now      - [IN] the current timestamp                          *
 *                                                                            *
 * Return Value: Timestamp when the next check must be scheduled.             *
 *                                                                            *
 ******************************************************************************/
static time_t	scheduler_get_nextcheck(zbx_scheduler_interval_t *interval, time_t now)
{
	struct tm	tm_start, tm;
	int		nextcheck = 0, current_nextcheck;

	tm_start = *(localtime(&now));
	tm_start.tm_isdst = -1;

	for (; NULL != interval; interval = interval->next)
	{
		tm = tm_start;

		scheduler_apply_day_filter(interval, &tm);
		scheduler_apply_hour_filter(interval, &tm);
		scheduler_apply_minute_filter(interval, &tm);
		scheduler_apply_second_filter(interval, &tm);

		current_nextcheck = mktime(&tm);

		if (0 == nextcheck || current_nextcheck < nextcheck)
			nextcheck = current_nextcheck;
	}

	return nextcheck;
}

/******************************************************************************
 *                                                                            *
 * Function: calculate_item_nextcheck                                         *
 *                                                                            *
 * Purpose: calculate nextcheck timestamp for item                            *
 *                                                                            *
 * Parameters: seed             - [IN] the seed value applied to delay to     *
 *                                     spread item checks over the delay      *
 *                                     period                                 *
 *             item_type        - [IN] the item type                          *
 *             delay            - [IN] default delay value, can be overridden *
 *             custom_intervals - [IN] descriptions of flexible intervals     *
 *                                     in the form [dd/d1-d2,hh:mm-hh:mm;]    *
 *             now              - [IN] current timestamp                      *
 *                                                                            *
 * Return value: nextcheck value                                              *
 *                                                                            *
 * Author: Alexei Vladishev, Aleksandrs Saveljevs                             *
 *                                                                            *
 * Comments: if item check is forbidden with delay=0 (default and flexible),  *
 *           a timestamp very far in the future is returned                   *
 *                                                                            *
 *           Old algorithm: now+delay                                         *
 *           New one: preserve period, if delay==5, nextcheck = 0,5,10,15,... *
 *           !!! Don't forget to sync code with PHP !!!                       *
 *                                                                            *
 ******************************************************************************/
int	calculate_item_nextcheck(zbx_uint64_t seed, int item_type, int delay, const char *custom_intervals, time_t now)
{
	int	nextcheck = 0;

	/* special processing of active items to see better view in queue */
	if (ITEM_TYPE_ZABBIX_ACTIVE == item_type)
	{
		if (0 != delay)
			nextcheck = (int)now + delay;
		else
			nextcheck = ZBX_JAN_2038;
	}
	else
	{
		int	current_delay = 0, try = 0;
		time_t	next_interval, t, tmax, scheduled_check = 0;
		char	*flex = NULL;
		size_t	flex_alloc = 0, flex_offset = 0;

		/* first try to parse out and calculate scheduled intervals */
		if (NULL != custom_intervals)
		{
			zbx_scheduler_interval_t	*interval = NULL;
			char				*errmsg = NULL;

			if (SUCCEED == preprocess_flexible_interval(custom_intervals, &interval, &flex, &flex_alloc,
					&flex_offset, &errmsg))
			{
				custom_intervals = flex;
				scheduled_check = scheduler_get_nextcheck(interval, now + 1);
				scheduler_interval_free(interval);
			}
			else
			{
				zabbix_log(LOG_LEVEL_ERR, "%s", errmsg);
				zbx_free(errmsg);
			}
		}

		/* Try to find the nearest 'nextcheck' value with condition */
		/* 'now' < 'nextcheck' < 'now' + SEC_PER_YEAR. If it is not */
		/* possible to check the item within a year, fail. */

		t = now;
		tmax = now + SEC_PER_YEAR;

		while (t < tmax)
		{
			/* calculate 'nextcheck' value for the current interval */
			current_delay = get_current_delay(delay, custom_intervals, t);

			if (0 != current_delay)
			{
				nextcheck = current_delay * (int)(t / (time_t)current_delay) +
						(int)(seed % (zbx_uint64_t)current_delay);

				if (0 == try)
				{
					while (nextcheck <= t)
						nextcheck += current_delay;
				}
				else
				{
					while (nextcheck < t)
						nextcheck += current_delay;
				}
			}
			else
				nextcheck = ZBX_JAN_2038;

			/* 'nextcheck' < end of the current interval ? */
			/* the end of the current interval is the beginning of the next interval - 1 */
			if (FAIL != get_next_delay_interval(custom_intervals, t, &next_interval) &&
					nextcheck >= next_interval)
			{
				/* 'nextcheck' is beyond the current interval */
				t = next_interval;
				try++;
			}
			else
				break;	/* nextcheck is within the current interval */
		}

		zbx_free(flex);

		if (0 != scheduled_check && scheduled_check < nextcheck)
			nextcheck = scheduled_check;
	}

	return nextcheck;
}

/******************************************************************************
 *                                                                            *
 * Function: calculate_proxy_nextcheck                                        *
 *                                                                            *
 * Purpose: calculate nextcheck timestamp for passive proxy                   *
 *                                                                            *
 * Parameters: hostid - [IN] host identificator from database                 *
 *             delay  - [IN] default delay value, can be overridden           *
 *             now    - [IN] current timestamp                                *
 *                                                                            *
 * Return value: nextcheck value                                              *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 ******************************************************************************/
time_t	calculate_proxy_nextcheck(zbx_uint64_t hostid, unsigned int delay, time_t now)
{
	time_t	nextcheck;

	nextcheck = delay * (now / delay) + (unsigned int)(hostid % delay);

	while (nextcheck <= now)
		nextcheck += delay;

	return nextcheck;
}

/******************************************************************************
 *                                                                            *
 * Function: is_ip4                                                           *
 *                                                                            *
 * Purpose: is string IPv4 address                                            *
 *                                                                            *
 * Parameters: ip - string                                                    *
 *                                                                            *
 * Return value: SUCCEED - is IPv4 address                                    *
 *               FAIL - otherwise                                             *
 *                                                                            *
 * Author: Alexei Vladishev, Alexander Vladishev                              *
 *                                                                            *
 ******************************************************************************/
int	is_ip4(const char *ip)
{
	const char	*__function_name = "is_ip4";
	const char	*p = ip;
	int		nums = 0, dots = 0, res = FAIL;

	zabbix_log(LOG_LEVEL_DEBUG, "In %s() ip:'%s'", __function_name, ip);

	while ('\0' != *p)
	{
		if (0 != isdigit(*p))
		{
			nums++;
		}
		else if ('.' == *p)
		{
			if (0 == nums || 3 < nums)
				break;
			nums = 0;
			dots++;
		}
		else
		{
			nums = 0;
			break;
		}

		p++;
	}
	if (dots == 3 && 1 <= nums && nums <= 3)
		res = SUCCEED;

	zabbix_log(LOG_LEVEL_DEBUG, "End of %s():%s", __function_name, zbx_result_string(res));

	return res;
}

#if defined(HAVE_IPV6)
/******************************************************************************
 *                                                                            *
 * Function: is_ip6                                                           *
 *                                                                            *
 * Purpose: is string IPv6 address                                            *
 *                                                                            *
 * Parameters: ip - string                                                    *
 *                                                                            *
 * Return value: SUCCEED - is IPv6 address                                    *
 *               FAIL - otherwise                                             *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 * Comments: could be improved (not supported x:x:x:x:x:x:d.d.d.d addresses)  *
 *                                                                            *
 ******************************************************************************/
int	is_ip6(const char *ip)
{
	const char	*__function_name = "is_ip6";
	const char	*p = ip;
	int		nums = 0, is_nums = 0, colons = 0, dcolons = 0, res = FAIL;

	zabbix_log(LOG_LEVEL_DEBUG, "In %s() ip:'%s'", __function_name, ip);

	while ('\0' != *p)
	{
		if (0 != isxdigit(*p))
		{
			nums++;
			is_nums = 1;
		}
		else if (':' == *p)
		{
			if (0 == nums && 0 < colons)
				dcolons++;
			if (4 < nums || 1 < dcolons)
				break;
			nums = 0;
			colons++;
		}
		else
		{
			is_nums = 0;
			break;
		}

		p++;
	}

	if (2 <= colons && colons <= 7 && 4 >= nums && 1 == is_nums)
		res = SUCCEED;

	zabbix_log(LOG_LEVEL_DEBUG, "End of %s():%s", __function_name, zbx_result_string(res));

	return res;
}
#endif	/*HAVE_IPV6*/

/******************************************************************************
 *                                                                            *
 * Function: is_ip                                                            *
 *                                                                            *
 * Purpose: is string IP address                                              *
 *                                                                            *
 * Parameters: ip - string                                                    *
 *                                                                            *
 * Return value: SUCCEED - is IP address                                      *
 *               FAIL - otherwise                                             *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 ******************************************************************************/
int	is_ip(const char *ip)
{
	zabbix_log(LOG_LEVEL_DEBUG, "In is_ip() ip:'%s'", ip);

	if (SUCCEED == is_ip4(ip))
		return SUCCEED;
#if defined(HAVE_IPV6)
	if (SUCCEED == is_ip6(ip))
		return SUCCEED;
#endif
	return FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: ip_in_list                                                       *
 *                                                                            *
 * Purpose: check if ip matches range of ip addresses                         *
 *                                                                            *
 * Parameters: list - [IN] comma-separated list of ip ranges                  *
 *                    192.168.0.1-64,192.168.0.128,10.10.0.0/24,12fc::21      *
 *             ip   - [IN] ip address                                         *
 *                                                                            *
 * Return value: FAIL - out of range, SUCCEED - within the range              *
 *                                                                            *
 ******************************************************************************/
int	ip_in_list(const char *list, const char *ip)
{
	const char	*__function_name = "ip_in_list";

	int		ipaddress[8];
	zbx_iprange_t	iprange;
	char		*address = NULL;
	size_t		address_alloc = 0, address_offset;
	const char	*ptr;
	int		ret = FAIL;

	zabbix_log(LOG_LEVEL_DEBUG, "In %s() list:'%s' ip:'%s'", __function_name, list, ip);

	if (SUCCEED != iprange_parse(&iprange, ip))
		goto out;
#ifndef HAVE_IPV6
	if (ZBX_IPRANGE_V6 == iprange.type)
		goto out;
#endif
	iprange_first(&iprange, ipaddress);

	for (ptr = list; '\0' != *ptr; list = ptr + 1)
	{
		if (NULL == (ptr = strchr(list, ',')))
			ptr = list + strlen(list);

		address_offset = 0;
		zbx_strncpy_alloc(&address, &address_alloc, &address_offset, list, ptr - list);

		if (SUCCEED != iprange_parse(&iprange, address))
			continue;
#ifndef HAVE_IPV6
		if (ZBX_IPRANGE_V6 == iprange.type)
			continue;
#endif
		if (SUCCEED == iprange_validate(&iprange, ipaddress))
		{
			ret = SUCCEED;
			break;
		}
	}

	zbx_free(address);
out:
	zabbix_log(LOG_LEVEL_DEBUG, "End of %s():%s", __function_name, zbx_result_string(ret));

	return ret;
}

/******************************************************************************
 *                                                                            *
 * Function: int_in_list                                                      *
 *                                                                            *
 * Purpose: check if integer matches a list of integers                       *
 *                                                                            *
 * Parameters: list  - integers [i1-i2,i3,i4,i5-i6] (10-25,45,67-699)         *
 *             value - integer to check                                       *
 *                                                                            *
 * Return value: FAIL - out of period, SUCCEED - within the period            *
 *                                                                            *
 * Author: Alexei Vladishev                                                   *
 *                                                                            *
 ******************************************************************************/
int	int_in_list(char *list, int value)
{
	const char	*__function_name = "int_in_list";
	char		*start = NULL, *end = NULL, c = '\0';
	int		i1, i2, ret = FAIL;

	zabbix_log(LOG_LEVEL_DEBUG, "In %s() list:'%s' value:%d", __function_name, list, value);

	for (start = list; '\0' != *start;)
	{
		if (NULL != (end = strchr(start, ',')))
		{
			c = *end;
			*end = '\0';
		}

		if (2 == sscanf(start, "%d-%d", &i1, &i2))
		{
			if (i1 <= value && value <= i2)
			{
				ret = SUCCEED;
				break;
			}
		}
		else
		{
			if (value == atoi(start))
			{
				ret = SUCCEED;
				break;
			}
		}

		if (NULL != end)
		{
			*end = c;
			start = end + 1;
		}
		else
			break;
	}

	if (NULL != end)
		*end = c;

	zabbix_log(LOG_LEVEL_DEBUG, "End of %s():%s", __function_name, zbx_result_string(ret));

	return ret;
}

int	zbx_double_compare(double a, double b)
{
	return fabs(a - b) < ZBX_DOUBLE_EPSILON ? SUCCEED : FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: is_double_suffix                                                 *
 *                                                                            *
 * Purpose: check if the string is double                                     *
 *                                                                            *
 * Parameters: str - string to check                                          *
 *                                                                            *
 * Return value:  SUCCEED - the string is double                              *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Alexei Vladishev                                                   *
 *                                                                            *
 * Comments: the function automatically processes suffixes K, M, G, T and     *
 *           s, m, h, d, w                                                    *
 *                                                                            *
 ******************************************************************************/
int	is_double_suffix(const char *str)
{
	size_t	i;
	char	dot = 0;

	for (i = 0; '\0' != str[i]; i++)
	{
		/* negative number? */
		if ('-' == str[i] && 0 == i)
			continue;

		if (0 != isdigit(str[i]))
			continue;

		if ('.' == str[i] && 0 == dot)
		{
			dot = 1;
			continue;
		}

		/* last character is suffix */
		if (NULL != strchr("KMGTsmhdw", str[i]) && '\0' == str[i + 1])
			continue;

		return FAIL;
	}

	return SUCCEED;
}

/******************************************************************************
 *                                                                            *
 * Function: is_double                                                        *
 *                                                                            *
 * Purpose: check if the string is double                                     *
 *                                                                            *
 * Parameters: str - string to check                                          *
 *                                                                            *
 * Return value:  SUCCEED - the string is double                              *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Alexei Vladishev, Aleksandrs Saveljevs                             *
 *                                                                            *
 ******************************************************************************/
int	is_double(const char *str)
{
	int	i = 0, digits = 0;

	while (' ' == str[i])				/* trim left spaces */
		i++;

	if ('-' == str[i] || '+' == str[i])		/* check leading sign */
		i++;

	while (0 != isdigit(str[i]))			/* check digits before dot */
	{
		i++;
		digits = 1;
	}

	if ('.' == str[i])				/* check decimal dot */
		i++;

	while (0 != isdigit(str[i]))			/* check digits after dot */
	{
		i++;
		digits = 1;
	}

	if (0 == digits)				/* 1., .1, and 1.1 are good, just . is not */
		return FAIL;

	if ('e' == str[i] || 'E' == str[i])		/* check exponential part */
	{
		i++;

		if ('-' == str[i] || '+' == str[i])	/* check exponent sign */
			i++;

		if (0 == isdigit(str[i]))		/* check exponent */
			return FAIL;

		while (0 != isdigit(str[i]))
			i++;
	}

	while (' ' == str[i])				/* trim right spaces */
		i++;

	return '\0' == str[i] ? SUCCEED : FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: is_uint_suffix                                                   *
 *                                                                            *
 * Purpose: check if the string is unsigned integer                           *
 *                                                                            *
 * Parameters: str   - string to check                                        *
 *             value - a pointer to converted value (optional)                *
 *                                                                            *
 * Return value: SUCCEED - the string is unsigned integer                     *
 *               FAIL    - otherwise                                          *
 *                                                                            *
 * Author: Aleksandrs Saveljevs, Vladimir Levijev                             *
 *                                                                            *
 * Comments: the function automatically processes suffixes s, m, h, d, w      *
 *                                                                            *
 ******************************************************************************/
int	is_uint_suffix(const char *str, unsigned int *value)
{
	const unsigned int	max_uint = ~0U;
	unsigned int		value_uint = 0, c, factor = 1;

	if ('\0' == *str || '0' > *str || *str > '9')
		return FAIL;

	while ('\0' != *str && 0 != isdigit(*str))
	{
		c = (unsigned int)(unsigned char)(*str - '0');

		if ((max_uint - c) / 10 < value_uint)
			return FAIL;	/* overflow */

		value_uint = value_uint * 10 + c;

		str++;
	}

	if ('\0' != *str)
	{
		switch (*str)
		{
			case 's':
				break;
			case 'm':
				factor = SEC_PER_MIN;
				break;
			case 'h':
				factor = SEC_PER_HOUR;
				break;
			case 'd':
				factor = SEC_PER_DAY;
				break;
			case 'w':
				factor = SEC_PER_WEEK;
				break;
			default:
				return FAIL;
		}

		str++;
	}

	if ('\0' != *str)
		return FAIL;

	if (max_uint / factor < value_uint)
		return FAIL;	/* overflow */

	if (NULL != value)
		*value = value_uint * factor;

	return SUCCEED;
}

#if defined(_WINDOWS)
int	_wis_uint(const wchar_t *wide_string)
{
	const wchar_t	*wide_char = wide_string;

	if (L'\0' == *wide_char)
		return FAIL;

	while (L'\0' != *wide_char)
	{
		if (0 != iswdigit(*wide_char))
		{
			wide_char++;
			continue;
		}
		return FAIL;
	}

	return SUCCEED;
}
#endif

/******************************************************************************
 *                                                                            *
 * Function: is_int_prefix                                                    *
 *                                                                            *
 * Purpose: check if the beginning of string is a signed integer              *
 *                                                                            *
 * Parameters: str - string to check                                          *
 *                                                                            *
 * Return value:  SUCCEED - the beginning of string is a signed integer       *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Aleksandrs Saveljevs                                               *
 *                                                                            *
 ******************************************************************************/
int	is_int_prefix(const char *str)
{
	size_t	i = 0;

	while (' ' == str[i])	/* trim left spaces */
		i++;

	if ('-' == str[i] || '+' == str[i])
		i++;

	if (0 == isdigit(str[i]))
		return FAIL;

	return SUCCEED;
}

/******************************************************************************
 *                                                                            *
 * Function: is_uint_n_range                                                  *
 *                                                                            *
 * Purpose: check if the string is unsigned integer within the specified      *
 *          range and optionally store it into value parameter                *
 *                                                                            *
 * Parameters: str   - [IN] string to check                                   *
 *             n     - [IN] string length or ZBX_MAX_UINT64_LEN               *
 *             value - [OUT] a pointer to output buffer where the converted   *
 *                     value is to be written (optional, can be NULL)         *
 *             size  - [IN] size of the output buffer (optional)              *
 *             min   - [IN] the minimum acceptable value                      *
 *             max   - [IN] the maximum acceptable value                      *
 *                                                                            *
 * Return value:  SUCCEED - the string is unsigned integer                    *
 *                FAIL - the string is not a number or its value is outside   *
 *                       the specified range                                  *
 *                                                                            *
 * Author: Alexander Vladishev, Andris Zeila                                  *
 *                                                                            *
 ******************************************************************************/
int	is_uint_n_range(const char *str, size_t n, void *value, size_t size, zbx_uint64_t min, zbx_uint64_t max)
{
	zbx_uint64_t		value_uint64 = 0, c;
	const zbx_uint64_t	max_uint64 = ~(zbx_uint64_t)__UINT64_C(0);

	if ('\0' == *str || 0 == n || sizeof(zbx_uint64_t) < size || (0 == size && NULL != value))
		return FAIL;

	while ('\0' != *str && 0 < n--)
	{
		if (0 == isdigit(*str))
			return FAIL;	/* not a digit */

		c = (zbx_uint64_t)(unsigned char)(*str - '0');

		if ((max_uint64 - c) / 10 < value_uint64)
			return FAIL;	/* maximum value exceeded */

		value_uint64 = value_uint64 * 10 + c;

		str++;
	}

	if (min > value_uint64 || value_uint64 > max)
		return FAIL;

	if (NULL != value)
	{
		/* On little endian architecture the output value will be stored starting from the first bytes */
		/* of 'value' buffer while on big endian architecture it will be stored starting from the last */
		/* bytes. We handle it by storing the offset in the most significant byte of short value and   */
		/* then use the first byte as source offset.                                                   */
		unsigned short	value_offset = (unsigned short)((sizeof(zbx_uint64_t) - size) << 8);

		memcpy(value, (unsigned char *)&value_uint64 + *((unsigned char *)&value_offset), size);
	}

	return SUCCEED;
}

/******************************************************************************
 *                                                                            *
 * Function: is_hex_n_range                                                   *
 *                                                                            *
 * Purpose: check if the string is unsigned hexadecimal integer within the    *
 *          specified range and optionally store it into value parameter      *
 *                                                                            *
 * Parameters: str   - [IN] string to check                                   *
 *             n     - [IN] string length                                     *
 *             value - [OUT] a pointer to output buffer where the converted   *
 *                     value is to be written (optional, can be NULL)         *
 *             size  - [IN] size of the output buffer (optional)              *
 *             min   - [IN] the minimum acceptable value                      *
 *             max   - [IN] the maximum acceptable value                      *
 *                                                                            *
 * Return value:  SUCCEED - the string is unsigned integer                    *
 *                FAIL - the string is not a hexadecimal number or its value  *
 *                       is outside the specified range                       *
 *                                                                            *
 ******************************************************************************/
int	is_hex_n_range(const char *str, size_t n, void *value, size_t size, zbx_uint64_t min, zbx_uint64_t max)
{
	zbx_uint64_t		value_uint64 = 0, c;
	const zbx_uint64_t	max_uint64 = ~(zbx_uint64_t)__UINT64_C(0);
	int			len = 0;

	if ('\0' == *str || 0 == n || sizeof(zbx_uint64_t) < size || (0 == size && NULL != value))
		return FAIL;

	while ('\0' != *str && 0 < n--)
	{
		if ('0' <= *str && *str <= '9')
			c = *str - '0';
		else if ('a' <= *str && *str <= 'f')
			c = 10 + (*str - 'a');
		else if ('A' <= *str && *str <= 'F')
			c = 10 + (*str - 'A');
		else
			return FAIL;	/* not a hexadecimal digit */

		if (16 < ++len && (max_uint64 >> 4) < value_uint64)
			return FAIL;	/* maximum value exceeded */

		value_uint64 = (value_uint64 << 4) + c;

		str++;
	}
	if (min > value_uint64 || value_uint64 > max)
		return FAIL;

	if (NULL != value)
	{
		/* On little endian architecture the output value will be stored starting from the first bytes */
		/* of 'value' buffer while on big endian architecture it will be stored starting from the last */
		/* bytes. We handle it by storing the offset in the most significant byte of short value and   */
		/* then use the first byte as source offset.                                                   */
		unsigned short	value_offset = (unsigned short)((sizeof(zbx_uint64_t) - size) << 8);

		memcpy(value, (unsigned char *)&value_uint64 + *((unsigned char *)&value_offset), size);
	}

	return SUCCEED;
}

/******************************************************************************
 *                                                                            *
 * Function: is_boolean                                                       *
 *                                                                            *
 * Purpose: check if the string is boolean                                    *
 *                                                                            *
 * Parameters: str - string to check                                          *
 *                                                                            *
 * Return value:  SUCCEED - the string is boolean                             *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Aleksandrs Saveljevs                                               *
 *                                                                            *
 * Comments:                                                                  *
 *                                                                            *
 ******************************************************************************/
int	is_boolean(const char *str, zbx_uint64_t *value)
{
	int	res;

	if (SUCCEED == (res = is_double(str)))
		*value = (0 != atof(str));
	else
	{
		char	tmp[16];

		strscpy(tmp, str);
		zbx_strlower(tmp);

		if (SUCCEED == (res = str_in_list("true,t,yes,y,on,up,running,enabled,available", tmp, ',')))
			*value = 1;
		else if (SUCCEED == (res = str_in_list("false,f,no,n,off,down,unused,disabled,unavailable", tmp, ',')))
			*value = 0;
	}

	return res;
}

/******************************************************************************
 *                                                                            *
 * Function: is_uoct                                                          *
 *                                                                            *
 * Purpose: check if the string is unsigned octal                             *
 *                                                                            *
 * Parameters: str - string to check                                          *
 *                                                                            *
 * Return value:  SUCCEED - the string is unsigned octal                      *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 ******************************************************************************/
int	is_uoct(const char *str)
{
	int	res = FAIL;

	while (' ' == *str)	/* trim left spaces */
		str++;

	for (; '\0' != *str; str++)
	{
		if (*str < '0' || *str > '7')
			break;

		res = SUCCEED;
	}

	while (' ' == *str)	/* check right spaces */
		str++;

	if ('\0' != *str)
		return FAIL;

	return res;
}

/******************************************************************************
 *                                                                            *
 * Function: is_uhex                                                          *
 *                                                                            *
 * Purpose: check if the string is unsigned hexadecimal                       *
 *                                                                            *
 * Parameters: str - string to check                                          *
 *                                                                            *
 * Return value:  SUCCEED - the string is unsigned hexadecimal                *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 ******************************************************************************/
int	is_uhex(const char *str)
{
	int	res = FAIL;

	while (' ' == *str)	/* trim left spaces */
		str++;

	for (; '\0' != *str; str++)
	{
		if (0 == isxdigit(*str))
			break;

		res = SUCCEED;
	}

	while (' ' == *str)	/* check right spaces */
		str++;

	if ('\0' != *str)
		return FAIL;

	return res;
}

/******************************************************************************
 *                                                                            *
 * Function: is_hex_string                                                    *
 *                                                                            *
 * Purpose: check if the string is a hexadecimal representation of data in    *
 *          the form "F4 CE 46 01 0C 44 8B F4\nA0 2C 29 74 5D 3F 13 49\n"     *
 *                                                                            *
 * Parameters: str - string to check                                          *
 *                                                                            *
 * Return value:  SUCCEED - the string is formatted like the example above    *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Aleksandrs Saveljevs                                               *
 *                                                                            *
 ******************************************************************************/
int	is_hex_string(const char *str)
{
	if ('\0' == *str)
		return FAIL;

	while ('\0' != *str)
	{
		if (0 == isxdigit(*str))
			return FAIL;

		if (0 == isxdigit(*(str + 1)))
			return FAIL;

		if ('\0' == *(str + 2))
			break;

		if (' ' != *(str + 2) && '\n' != *(str + 2))
			return FAIL;

		str += 3;
	}

	return SUCCEED;
}

/******************************************************************************
 *                                                                            *
 * Function: get_nearestindex                                                 *
 *                                                                            *
 * Purpose: get nearest index position of sorted elements in array            *
 *                                                                            *
 * Parameters: p   - pointer to array of elements                             *
 *             sz  - element size                                             *
 *             num - number of elements                                       *
 *             id  - index to look for                                        *
 *                                                                            *
 * Return value: index at which it would be possible to insert the element so *
 *               that the array is still sorted                               *
 *                                                                            *
 ******************************************************************************/
int	get_nearestindex(const void *p, size_t sz, int num, zbx_uint64_t id)
{
	int		first_index, last_index, index;
	zbx_uint64_t	element_id;

	if (0 == num)
		return 0;

	first_index = 0;
	last_index = num - 1;

	while (1)
	{
		index = first_index + (last_index - first_index) / 2;

		if (id == (element_id = *(const zbx_uint64_t *)((const char *)p + index * sz)))
			return index;

		if (last_index == first_index)
		{
			if (element_id < id)
				index++;
			return index;
		}

		if (element_id < id)
			first_index = index + 1;
		else
			last_index = index;
	}
}

/******************************************************************************
 *                                                                            *
 * Function: uint64_array_add                                                 *
 *                                                                            *
 * Purpose: add uint64 value to dynamic array                                 *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 ******************************************************************************/
int	uint64_array_add(zbx_uint64_t **values, int *alloc, int *num, zbx_uint64_t value, int alloc_step)
{
	int	index;

	index = get_nearestindex(*values, sizeof(zbx_uint64_t), *num, value);
	if (index < (*num) && (*values)[index] == value)
		return index;

	if (*alloc == *num)
	{
		if (0 == alloc_step)
		{
			zbx_error("Unable to reallocate buffer");
			assert(0);
		}

		*alloc += alloc_step;
		*values = zbx_realloc(*values, *alloc * sizeof(zbx_uint64_t));
	}

	memmove(&(*values)[index + 1], &(*values)[index], sizeof(zbx_uint64_t) * (*num - index));

	(*values)[index] = value;
	(*num)++;

	return index;
}

/******************************************************************************
 *                                                                            *
 * Function: uint64_array_exists                                              *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 ******************************************************************************/
int	uint64_array_exists(const zbx_uint64_t *values, int num, zbx_uint64_t value)
{
	int	index;

	index = get_nearestindex(values, sizeof(zbx_uint64_t), num, value);
	if (index < num && values[index] == value)
		return SUCCEED;

	return FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: uint64_array_remove                                              *
 *                                                                            *
 * Purpose: remove uint64 values from array                                   *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 ******************************************************************************/
void	uint64_array_remove(zbx_uint64_t *values, int *num, const zbx_uint64_t *rm_values, int rm_num)
{
	int	rindex, index;

	for (rindex = 0; rindex < rm_num; rindex++)
	{
		index = get_nearestindex(values, sizeof(zbx_uint64_t), *num, rm_values[rindex]);
		if (index == *num || values[index] != rm_values[rindex])
			continue;

		memmove(&values[index], &values[index + 1], sizeof(zbx_uint64_t) * ((*num) - index - 1));
		(*num)--;
	}
}

zbx_uint64_t	suffix2factor(char c)
{
	switch (c)
	{
		case 'K':
			return ZBX_KIBIBYTE;
		case 'M':
			return ZBX_MEBIBYTE;
		case 'G':
			return ZBX_GIBIBYTE;
		case 'T':
			return ZBX_TEBIBYTE;
		case 's':
			return 1;
		case 'm':
			return SEC_PER_MIN;
		case 'h':
			return SEC_PER_HOUR;
		case 'd':
			return SEC_PER_DAY;
		case 'w':
			return SEC_PER_WEEK;
		default:
			return 1;
	}
}

/******************************************************************************
 *                                                                            *
 * Function: str2uint64                                                       *
 *                                                                            *
 * Purpose: convert string to 64bit unsigned integer                          *
 *                                                                            *
 * Parameters: str   - string to convert                                      *
 *             value - a pointer to converted value                           *
 *                                                                            *
 * Return value:  SUCCEED - the string is unsigned integer                    *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 * Comments: the function automatically processes suffixes K, M, G, T         *
 *                                                                            *
 ******************************************************************************/
int	str2uint64(const char *str, const char *suffixes, zbx_uint64_t *value)
{
	size_t		sz;
	const char	*p;
	int		ret;
	zbx_uint64_t	factor = 1;

	sz = strlen(str);
	p = str + sz - 1;

	if (NULL != strchr(suffixes, *p))
	{
		factor = suffix2factor(*p);

		sz--;
	}

	if (SUCCEED == (ret = is_uint64_n(str, sz, value)))
		*value *= factor;

	return ret;
}

/******************************************************************************
 *                                                                            *
 * Function: str2double                                                       *
 *                                                                            *
 * Purpose: convert string to double                                          *
 *                                                                            *
 * Parameters: str - string to convert                                        *
 *                                                                            *
 * Return value: converted double value                                       *
 *                                                                            *
 * Author: Alexei Vladishev                                                   *
 *                                                                            *
 * Comments: the function automatically processes suffixes K, M, G, T and     *
 *           s, m, h, d, w                                                    *
 *                                                                            *
 ******************************************************************************/
double	str2double(const char *str)
{
	size_t	sz;

	sz = strlen(str) - 1;

	return atof(str) * suffix2factor(str[sz]);
}

/******************************************************************************
 *                                                                            *
 * Function: is_hostname_char                                                 *
 *                                                                            *
 * Return value:  SUCCEED - the char is allowed in the host name              *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 * Comments: in host name allowed characters: '0-9a-zA-Z. _-'                 *
 *           !!! Don't forget to sync the code with PHP !!!                   *
 *                                                                            *
 ******************************************************************************/
int	is_hostname_char(unsigned char c)
{
	if (0 != isalnum(c))
		return SUCCEED;

	if (c == '.' || c == ' ' || c == '_' || c == '-')
		return SUCCEED;

	return FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: is_key_char                                                      *
 *                                                                            *
 * Return value:  SUCCEED - the char is allowed in the item key               *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 * Comments: in key allowed characters: '0-9a-zA-Z._-'                        *
 *           !!! Don't forget to sync the code with PHP !!!                   *
 *                                                                            *
 ******************************************************************************/
int	is_key_char(unsigned char c)
{
	if (0 != isalnum(c))
		return SUCCEED;

	if (c == '.' || c == '_' || c == '-')
		return SUCCEED;

	return FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: is_function_char                                                 *
 *                                                                            *
 * Return value:  SUCCEED - the char is allowed in the trigger function       *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 * Comments: in trigger function allowed characters: 'a-z'                    *
 *           !!! Don't forget to sync the code with PHP !!!                   *
 *                                                                            *
 ******************************************************************************/
int	is_function_char(unsigned char c)
{
	if (0 != islower(c))
		return SUCCEED;

	return FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: is_macro_char                                                    *
 *                                                                            *
 * Return value:  SUCCEED - the char is allowed in the macro name             *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 * Comments: allowed characters in macro names: '0-9A-Z._'                    *
 *           !!! Don't forget to sync the code with PHP !!!                   *
 *                                                                            *
 ******************************************************************************/
int	is_macro_char(unsigned char c)
{
	if (0 != isupper(c))
		return SUCCEED;

	if ('.' == c || '_' == c)
		return SUCCEED;

	if (0 != isdigit(c))
		return SUCCEED;

	return FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: is_discovery_macro                                               *
 *                                                                            *
 * Purpose: checks if the name is a valid discovery macro                     *
 *                                                                            *
 * Return value:  SUCCEED - the name is a valid discovery macro               *
 *                FAIL - otherwise                                            *
 *                                                                            *
 ******************************************************************************/
int	is_discovery_macro(const char *name)
{
	if ('{' != *name++ || '#' != *name++)
		return FAIL;

	do
	{
		if (SUCCEED != is_macro_char(*name++))
			return FAIL;

	} while ('}' != *name);

	if ('\0' != name[1])
		return FAIL;

	return SUCCEED;
}

/******************************************************************************
 *                                                                            *
 * Function: is_time_function                                                 *
 *                                                                            *
 * Return value:  SUCCEED - given function is time-based                      *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Aleksandrs Saveljevs                                               *
 *                                                                            *
 ******************************************************************************/
int	is_time_function(const char *func)
{
	return str_in_list("nodata,date,dayofmonth,dayofweek,time,now", func, ',');
}

/******************************************************************************
 *                                                                            *
 * Function: is_snmp_type                                                     *
 *                                                                            *
 * Return value:  SUCCEED  - the given type is one of regular SNMP types      *
 *                FAIL - otherwise                                            *
 *                                                                            *
 * Author: Aleksandrs Saveljevs                                               *
 *                                                                            *
 ******************************************************************************/
int	is_snmp_type(unsigned char type)
{
	return ITEM_TYPE_SNMPv1 == type || ITEM_TYPE_SNMPv2c == type || ITEM_TYPE_SNMPv3 == type ? SUCCEED : FAIL;
}

/******************************************************************************
 *                                                                            *
 * Function: make_hostname                                                    *
 *                                                                            *
 * Purpose: replace all not-allowed hostname characters in the string         *
 *                                                                            *
 * Parameters: host - the target C-style string                               *
 *                                                                            *
 * Author: Dmitry Borovikov                                                   *
 *                                                                            *
 * Comments: the string must be null-terminated, otherwise not secure!        *
 *                                                                            *
 ******************************************************************************/
void	make_hostname(char *host)
{
	char	*c;

	assert(host);

	for (c = host; '\0' != *c; ++c)
	{
		if (FAIL == is_hostname_char(*c))
			*c = '_';
	}
}

/******************************************************************************
 *                                                                            *
 * Function: get_interface_type_by_item_type                                  *
 *                                                                            *
 * Purpose:                                                                   *
 *                                                                            *
 * Parameters:                                                                *
 *                                                                            *
 * Return value: Interface type                                               *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 * Comments: !!! Don't forget to sync the code with PHP !!!                   *
 *                                                                            *
 ******************************************************************************/
unsigned char	get_interface_type_by_item_type(unsigned char type)
{
	switch (type)
	{
		case ITEM_TYPE_ZABBIX:
			return INTERFACE_TYPE_AGENT;
		case ITEM_TYPE_SNMPv1:
		case ITEM_TYPE_SNMPv2c:
		case ITEM_TYPE_SNMPv3:
		case ITEM_TYPE_SNMPTRAP:
			return INTERFACE_TYPE_SNMP;
		case ITEM_TYPE_IPMI:
			return INTERFACE_TYPE_IPMI;
		case ITEM_TYPE_JMX:
			return INTERFACE_TYPE_JMX;
		case ITEM_TYPE_SIMPLE:
		case ITEM_TYPE_EXTERNAL:
		case ITEM_TYPE_SSH:
		case ITEM_TYPE_TELNET:
			return INTERFACE_TYPE_ANY;
		default:
			return INTERFACE_TYPE_UNKNOWN;
	}
}

/******************************************************************************
 *                                                                            *
 * Function: calculate_sleeptime                                              *
 *                                                                            *
 * Purpose: calculate sleep time for Zabbix processes                         *
 *                                                                            *
 * Parameters: nextcheck     - [IN] next check or -1 (FAIL) if nothing to do  *
 *             max_sleeptime - [IN] maximum sleep time, in seconds            *
 *                                                                            *
 * Return value: sleep time, in seconds                                       *
 *                                                                            *
 * Author: Alexander Vladishev                                                *
 *                                                                            *
 ******************************************************************************/
int	calculate_sleeptime(int nextcheck, int max_sleeptime)
{
	int	sleeptime;

	if (FAIL == nextcheck)
		return max_sleeptime;

	sleeptime = nextcheck - (int)time(NULL);

	if (sleeptime < 0)
		return 0;

	if (sleeptime > max_sleeptime)
		return max_sleeptime;

	return sleeptime;
}

/******************************************************************************
 *                                                                            *
 * Function: parse_serveractive_element                                       *
 *                                                                            *
 * Purpose: parse a ServerActive element like "IP<:port>" or "[IPv6]<:port>"  *
 *                                                                            *
 ******************************************************************************/
int	parse_serveractive_element(char *str, char **host, unsigned short *port, unsigned short port_default)
{
#ifdef HAVE_IPV6
	char	*r1 = NULL;
#endif
	char	*r2 = NULL;
	int	res = FAIL;

	*port = port_default;

#ifdef HAVE_IPV6
	if ('[' == *str)
	{
		str++;

		if (NULL == (r1 = strchr(str, ']')))
			goto fail;

		if (':' != r1[1] && '\0' != r1[1])
			goto fail;

		if (':' == r1[1] && SUCCEED != is_ushort(r1 + 2, port))
			goto fail;

		*r1 = '\0';

		if (SUCCEED != is_ip6(str))
			goto fail;

		*host = zbx_strdup(*host, str);
	}
	else if (SUCCEED == is_ip6(str))
	{
		*host = zbx_strdup(*host, str);
	}
	else
	{
#endif
		if (NULL != (r2 = strchr(str, ':')))
		{
			if (SUCCEED != is_ushort(r2 + 1, port))
				goto fail;

			*r2 = '\0';
		}

		*host = zbx_strdup(NULL, str);
#ifdef HAVE_IPV6
	}
#endif

	res = SUCCEED;
fail:
#ifdef HAVE_IPV6
	if (NULL != r1)
		*r1 = ']';
#endif
	if (NULL != r2)
		*r2 = ':';

	return res;
}

#if !defined(_WINDOWS)
unsigned int	zbx_alarm_on(unsigned int seconds)
{
	zbx_timed_out = 0;

	return alarm(seconds);
}

unsigned int	zbx_alarm_off(void)
{
	unsigned int	ret;

	ret = alarm(0);
	zbx_timed_out = 0;
	return ret;
}
#endif
