/*
** Copyright (C) 2001-2024 Zabbix SIA
**
** This program is free software: you can redistribute it and/or modify it under the terms of
** the GNU Affero General Public License as published by the Free Software Foundation, version 3.
**
** 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 Affero General Public License for more details.
**
** You should have received a copy of the GNU Affero General Public License along with this program.
** If not, see <https://www.gnu.org/licenses/>.
**/

/* Enable wide (64-bit) interfaces for narrow (32-bit) applications (see pstat(2) for details). */
/* Without this on some HP-UX systems you can get runtime error when calling pstat_getproc(): */
/* Value too large to be stored in data type */
#ifndef _PSTAT64
#	define _PSTAT64
#endif

#include "zbxsysinfo.h"
#include "../sysinfo.h"

#include "zbxregexp.h"
#include "zbxstr.h"

#include <sys/pstat.h>

static int	check_procstate(struct pst_status pst, int zbx_proc_stat)
{
	if (ZBX_PROC_STAT_ALL == zbx_proc_stat)
		return SUCCEED;

	switch (zbx_proc_stat)
	{
		case ZBX_PROC_STAT_RUN:
			return PS_RUN == pst.pst_stat ? SUCCEED : FAIL;
		case ZBX_PROC_STAT_SLEEP:
			return PS_SLEEP == pst.pst_stat ? SUCCEED : FAIL;
		case ZBX_PROC_STAT_ZOMB:
			return PS_ZOMBIE == pst.pst_stat ? SUCCEED : FAIL;
	}

	return FAIL;
}

int	proc_num(AGENT_REQUEST *request, AGENT_RESULT *result)
{
#define ZBX_BURST	((size_t)10)
	char			*procname, *proccomm, *param, *rxp_error = NULL;
	struct passwd		*usrinfo;
	int			proccount = 0, invalid_user = 0, zbx_proc_stat, count, idx = 0;
	struct pst_status	pst[ZBX_BURST];
	zbx_regexp_t		*proccomm_rxp = NULL;

	if (4 < request->nparam)
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Too many parameters."));
		return SYSINFO_RET_FAIL;
	}

	procname = get_rparam(request, 0);
	if (NULL != procname && '\0' == *procname)
		procname = NULL;

	param = get_rparam(request, 1);
	if (NULL != param && '\0' != *param)
	{
		errno = 0;

		if (NULL == (usrinfo = getpwnam(param)))
		{
			if (0 != errno)
			{
				SET_MSG_RESULT(result, zbx_dsprintf(NULL, "Cannot obtain user information: %s",
							zbx_strerror(errno)));
				return SYSINFO_RET_FAIL;
			}

			invalid_user = 1;
		}
	}
	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
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Invalid third parameter."));
		return SYSINFO_RET_FAIL;
	}

	proccomm = get_rparam(request, 3);

	if (NULL != proccomm)
	{
		if ('\0' == *proccomm)
		{
			proccomm = NULL;
		}
		else if (SUCCEED != zbx_regexp_compile(proccomm, &proccomm_rxp, &rxp_error))
		{
			SET_MSG_RESULT(result, zbx_dsprintf(NULL, "Invalid regular expression in fourth parameter: "
					"%s", rxp_error));

			zbx_free(rxp_error);
			return SYSINFO_RET_FAIL;
		}
	}

	if (1 == invalid_user)	/* handle 0 for non-existent user after all parameters have been parsed and validated */
		goto out;

	memset(pst, 0, sizeof(pst));

	while (0 < (count = pstat_getproc(pst, sizeof(*pst), ZBX_BURST, idx)))
	{
		for (int i = 0; i < count; i++)
		{
			if (NULL != procname && 0 != strcmp(pst[i].pst_ucomm, procname))
				continue;

			if (NULL != usrinfo && usrinfo->pw_uid != pst[i].pst_uid)
				continue;

			if (NULL != proccomm)
			{
				union pstun	un;
				char		cmdline[1024];	/* up to 1020 characters from HP-UX */

				/* pstat_getcommandline() is available only from HP-UX 11i v2. */
				/* To handle HP-UX 11.11 a popular workaround is used. */
				un.pst_command = cmdline;
				if (-1 == pstat(PSTAT_GETCOMMANDLINE, un, sizeof(cmdline), 1, pst[i].pst_pid))
					continue;

				if (0 != zbx_regexp_match_precompiled(cmdline, proccomm_rxp))
					continue;
			}

			if (FAIL == check_procstate(pst[i], zbx_proc_stat))
				continue;

			proccount++;
		}

		idx = pst[count - 1].pst_idx + 1;
		memset(pst, 0, sizeof(pst));
	}

	if (-1 == count)
	{
		SET_MSG_RESULT(result, zbx_strdup(NULL, "Cannot obtain process information."));

		if (NULL != proccomm_rxp)
			zbx_regexp_free(proccomm_rxp);

		return SYSINFO_RET_FAIL;
	}
out:
	SET_UI64_RESULT(result, proccount);

	if (NULL != proccomm_rxp)
		zbx_regexp_free(proccomm_rxp);

	return SYSINFO_RET_OK;
#undef ZBX_BURST
}