/*
** Zabbix
** Copyright (C) 2001-2018 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 "sysinfo.h"
#include "zbxregexp.h"

#define DO_SUM 0
#define DO_MAX 1
#define DO_MIN 2
#define DO_AVG 3

static int	get_cmdline(FILE *f_cmd, char **line, size_t *line_offset)
{
	size_t	line_alloc = ZBX_KIBIBYTE, n;

	rewind(f_cmd);

	*line = zbx_malloc(*line, line_alloc + 2);
	*line_offset = 0;

	while (0 != (n = fread(*line + *line_offset, 1, line_alloc - *line_offset, f_cmd)))
	{
		*line_offset += n;

		if (0 != feof(f_cmd))
			break;

		line_alloc *= 2;
		*line = zbx_realloc(*line, line_alloc + 2);
	}

	if (0 == ferror(f_cmd))
	{
		if (0 == *line_offset || '\0' != (*line)[*line_offset - 1])
			(*line)[(*line_offset)++] = '\0';
		if (1 == *line_offset || '\0' != (*line)[*line_offset - 2])
			(*line)[(*line_offset)++] = '\0';

		return SUCCEED;
	}

	zbx_free(*line);

	return FAIL;
}

static int	cmp_status(FILE *f_stat, const char *procname)
{
	char	tmp[MAX_STRING_LEN];

	rewind(f_stat);

	while (NULL != fgets(tmp, sizeof(tmp), f_stat))
	{
		if (0 != strncmp(tmp, "Name:\t", 6))
			continue;

		zbx_rtrim(tmp + 6, "\n");
		if (0 == strcmp(tmp + 6, procname))
			return SUCCEED;
		break;
	}

	return FAIL;
}

static int	check_procname(FILE *f_cmd, FILE *f_stat, const char *procname)
{
	char	*tmp = NULL, *p;
	size_t	l;
	int	ret = SUCCEED;

	if (NULL == procname || '\0' == *procname)
		return SUCCEED;

	/* process name in /proc/[pid]/status contains limited number of characters */
	if (SUCCEED == cmp_status(f_stat, procname))
		return SUCCEED;

	if (SUCCEED == get_cmdline(f_cmd, &tmp, &l))
	{
		if (NULL == (p = strrchr(tmp, '/')))
			p = tmp;
		else
			p++;

		if (0 == strcmp(p, procname))
			goto clean;
	}

	ret = FAIL;
clean:
	zbx_free(tmp);

	return ret;
}

static int	check_user(FILE *f_stat, struct passwd *usrinfo)
{
	char	tmp[MAX_STRING_LEN], *p, *p1;
	uid_t	uid;

	if (NULL == usrinfo)
		return SUCCEED;

	rewind(f_stat);

	while (NULL != fgets(tmp, sizeof(tmp), f_stat))
	{
		if (0 != strncmp(tmp, "Uid:\t", 5))
			continue;

		p = tmp + 5;

		if (NULL != (p1 = strchr(p, '\t')))
			*p1 = '\0';

		uid = (uid_t)atoi(p);

		if (usrinfo->pw_uid == uid)
			return SUCCEED;
		break;
	}

	return FAIL;
}

static int	check_proccomm(FILE *f_cmd, const char *proccomm)
{
	char	*tmp = NULL;
	size_t	i, l;
	int	ret = SUCCEED;

	if (NULL == proccomm || '\0' == *proccomm)
		return SUCCEED;

	if (SUCCEED == get_cmdline(f_cmd, &tmp, &l))
	{
		for (i = 0, l -= 2; i < l; i++)
			if ('\0' == tmp[i])
				tmp[i] = ' ';

		if (NULL != zbx_regexp_match(tmp, proccomm, NULL))
			goto clean;
	}

	ret = FAIL;
clean:
	zbx_free(tmp);

	return ret;
}

static int	check_procstate(FILE *f_stat, int zbx_proc_stat)
{
	char	tmp[MAX_STRING_LEN], *p;

	if (ZBX_PROC_STAT_ALL == zbx_proc_stat)
		return SUCCEED;

	rewind(f_stat);

	while (NULL != fgets(tmp, sizeof(tmp), f_stat))
	{
		if (0 != strncmp(tmp, "State:\t", 7))
			continue;

		p = tmp + 7;

		switch (zbx_proc_stat)
		{
			case ZBX_PROC_STAT_RUN:
				return ('R' == *p) ? SUCCEED : FAIL;
			case ZBX_PROC_STAT_SLEEP:
				return ('S' == *p) ? SUCCEED : FAIL;
			case ZBX_PROC_STAT_ZOMB:
				return ('Z' == *p) ? SUCCEED : FAIL;
			default:
				return FAIL;
		}
	}

	return FAIL;
}

int	PROC_MEM(AGENT_REQUEST *request, AGENT_RESULT *result)
{
	char		tmp[MAX_STRING_LEN], *p, *p1, *procname, *proccomm, *param;
	DIR		*dir;
	struct dirent	*entries;
	struct passwd	*usrinfo;
	FILE		*f_cmd = NULL, *f_stat = NULL;
	zbx_uint64_t	value = 0;
	int		do_task, proccount = 0;
	double		memsize = 0;

	if (4 < request->nparam)
		return SYSINFO_RET_FAIL;

	procname = get_rparam(request, 0);
	param = get_rparam(request, 1);

	if (NULL != param && '\0' != *param)
	{
		if (NULL == (usrinfo = getpwnam(param)))	/* incorrect user name */
			return SYSINFO_RET_FAIL;
	}
	else
		usrinfo = NULL;

	param = get_rparam(request, 2);

	if (NULL == param || '\0' == *param || 0 == strcmp(param, "sum"))
		do_task = DO_SUM;
	else if (0 == strcmp(param, "avg"))
		do_task = DO_AVG;
	else if (0 == strcmp(param, "max"))
		do_task = DO_MAX;
	else if (0 == strcmp(param, "min"))
		do_task = DO_MIN;
	else
		return SYSINFO_RET_FAIL;

	proccomm = get_rparam(request, 3);

	if (NULL == (dir = opendir("/proc")))
		return SYSINFO_RET_FAIL;

	while (NULL != (entries = readdir(dir)))
	{
		zbx_fclose(f_cmd);
		zbx_fclose(f_stat);

		/* Self is a symbolic link. It leads to incorrect results for proc_cnt[zabbix_agentd]. */
		/* Better approach: check if /proc/x/ is symbolic link. */
		if (0 == strncmp(entries->d_name, "self", MAX_STRING_LEN))
			continue;

		zbx_snprintf(tmp, sizeof(tmp), "/proc/%s/cmdline", entries->d_name);

		if (NULL == (f_cmd = fopen(tmp, "r")))
			continue;

		zbx_snprintf(tmp, sizeof(tmp), "/proc/%s/status", entries->d_name);

		if (NULL == (f_stat = fopen(tmp, "r")))
			continue;

		if (FAIL == check_procname(f_cmd, f_stat, procname))
			continue;

		if (FAIL == check_user(f_stat, usrinfo))
			continue;

		if (FAIL == check_proccomm(f_cmd, proccomm))
			continue;

		rewind(f_stat);

		while (NULL != fgets(tmp, sizeof(tmp), f_stat))
		{
			if (0 != strncmp(tmp, "VmSize:\t", 8))
				continue;

			p = tmp + 8;

			if (NULL == (p1 = strrchr(p, ' ')))
				continue;

			*p1++ = '\0';

			sscanf(p, ZBX_FS_UI64, &value);

			zbx_rtrim(p1, "\n");

			if (0 == strcasecmp(p1, "kB"))
				value <<= 10;
			else if (0 == strcasecmp(p1, "mB"))
				value <<= 20;
			else if (0 == strcasecmp(p1, "GB"))
				value <<= 30;
			else if (0 == strcasecmp(p1, "TB"))
				value <<= 40;

			if (0 == proccount++)
				memsize = value;
			else
			{
				if (DO_MAX == do_task)
					memsize = MAX(memsize, value);
				else if (DO_MIN == do_task)
					memsize = MIN(memsize, value);
				else
					memsize += value;
			}
			break;
		}
	}
	zbx_fclose(f_cmd);
	zbx_fclose(f_stat);
	closedir(dir);

	if (do_task == DO_AVG)
	{
		SET_DBL_RESULT(result, proccount == 0 ? 0 : memsize / proccount);
	}
	else
		SET_UI64_RESULT(result, memsize);

	return SYSINFO_RET_OK;
}

int	PROC_NUM(AGENT_REQUEST *request, AGENT_RESULT *result)
{
	char		tmp[MAX_STRING_LEN], *procname, *proccomm, *param;
	DIR		*dir;
	struct dirent	*entries;
	struct passwd	*usrinfo;
	FILE		*f_cmd = NULL, *f_stat = NULL;
	int		zbx_proc_stat;
	zbx_uint64_t	proccount = 0;

	if (4 < request->nparam)
		return SYSINFO_RET_FAIL;

	procname = get_rparam(request, 0);
	param = get_rparam(request, 1);

	if (NULL != param && '\0' != *param)
	{
		if (NULL == (usrinfo = getpwnam(param)))	/* incorrect user name */
			return SYSINFO_RET_FAIL;
	}
	else
		usrinfo = NULL;

	param = get_rparam(request, 2);

	if (NULL == param || '\0' == *param || 0 == strcmp(param, "all"))
		zbx_proc_stat = ZBX_PROC_STAT_ALL;
	else if (0 == strcmp(param, "run"))
		zbx_proc_stat = ZBX_PROC_STAT_RUN;
	else if (0 == strcmp(param, "sleep"))
		zbx_proc_stat = ZBX_PROC_STAT_SLEEP;
	else if (0 == strcmp(param, "zomb"))
		zbx_proc_stat = ZBX_PROC_STAT_ZOMB;
	else
		return SYSINFO_RET_FAIL;

	proccomm = get_rparam(request, 3);

	if (NULL == (dir = opendir("/proc")))
		return SYSINFO_RET_FAIL;

	while (NULL != (entries = readdir(dir)))
	{
		zbx_fclose(f_cmd);
		zbx_fclose(f_stat);

		/* Self is a symbolic link. It leads to incorrect results for proc_cnt[zabbix_agentd] */
		/* Better approach: check if /proc/x/ is symbolic link */
		if (0 == strncmp(entries->d_name, "self", MAX_STRING_LEN))
			continue;

		zbx_snprintf(tmp, sizeof(tmp), "/proc/%s/cmdline", entries->d_name);

		if (NULL == (f_cmd = fopen(tmp, "r")))
			continue;

		zbx_snprintf(tmp, sizeof(tmp), "/proc/%s/status", entries->d_name);

		if (NULL == (f_stat = fopen(tmp, "r")))
			continue;

		if (FAIL == check_procname(f_cmd, f_stat, procname))
			continue;

		if (FAIL == check_user(f_stat, usrinfo))
			continue;

		if (FAIL == check_proccomm(f_cmd, proccomm))
			continue;

		if (FAIL == check_procstate(f_stat, zbx_proc_stat))
			continue;

		proccount++;
	}
	zbx_fclose(f_cmd);
	zbx_fclose(f_stat);
	closedir(dir);

	SET_UI64_RESULT(result, proccount);

	return SYSINFO_RET_OK;
}
