/* omprog.c
 * This output plugin enables rsyslog to execute a program and
 * feed it the message stream as standard input.
 *
 * NOTE: read comments in module-template.h for more specifics!
 *
 * File begun on 2009-04-01 by RGerhards
 *
 * Copyright 2009 Rainer Gerhards and Adiscon GmbH.
 *
 * This file is part of rsyslog.
 *
 * Rsyslog 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 3 of the License, or
 * (at your option) any later version.
 *
 * Rsyslog 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 Rsyslog.  If not, see <http://www.gnu.org/licenses/>.
 *
 * A copy of the GPL can be found in the file "COPYING" in this distribution.
 */
#include "config.h"
#include "rsyslog.h"
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <signal.h>
#include <errno.h>
#include <unistd.h>
#include "dirty.h"
#include "syslogd-types.h"
#include "srUtils.h"
#include "template.h"
#include "module-template.h"
#include "errmsg.h"
#include "cfsysline.h"

MODULE_TYPE_OUTPUT

/* internal structures
 */
DEF_OMOD_STATIC_DATA

typedef struct _instanceData {
	uchar *szBinary;	/* name of binary to call */
	pid_t pid;		/* pid of currently running process */
	int fdPipe;		/* file descriptor to write to */
	int bIsRunning;		/* is binary currently running? 0-no, 1-yes */
} instanceData;

/* config settings */
static uchar *szBinary = NULL;	/* name of binary to call */

BEGINcreateInstance
CODESTARTcreateInstance
ENDcreateInstance


BEGINisCompatibleWithFeature
CODESTARTisCompatibleWithFeature
	if(eFeat == sFEATURERepeatedMsgReduction)
		iRet = RS_RET_OK;
ENDisCompatibleWithFeature


BEGINfreeInstance
CODESTARTfreeInstance
ENDfreeInstance


BEGINdbgPrintInstInfo
CODESTARTdbgPrintInstInfo
ENDdbgPrintInstInfo


BEGINtryResume
CODESTARTtryResume
ENDtryResume

/* creates a pipe and starts program, uses pipe as stdin for program.
 * rgerhards, 2009-04-01
 */
static rsRetVal
openPipe(instanceData *pData)
{
	int pipefd[2];
	pid_t cpid;
	char *newargv[] = { NULL };
	char *newenviron[] = { NULL };
	DEFiRet;

	assert(pData != NULL);

	if(pipe(pipefd) == -1) {
		ABORT_FINALIZE(RS_RET_ERR_CREAT_PIPE);
	}

	cpid = fork();
	if(cpid == -1) {
		ABORT_FINALIZE(RS_RET_ERR_FORK);
	}

	if(cpid == 0) {    
		/* we are now the child, just set the right selectors and
		 * exec the binary. If that fails, there is not much we can do.
		 */
		fclose(stdin);
		dup(pipefd[0]);
		close(pipefd[1]);
		//fclose(stdout);
fprintf(stderr, "Program to exec '%s', fdPipe: %d\n", pData->szBinary, pipefd[0]);
		execve((char*)pData->szBinary, newargv, newenviron);
	}

	pData->fdPipe = pipefd[1];
	pData->pid = cpid;
	close(pipefd[0]);
	pData->bIsRunning = 1;
finalize_it:
	RETiRet;
}


BEGINdoAction
CODESTARTdoAction
	if(pData->bIsRunning == 0) {
		openPipe(pData);
	}

	write(pData->fdPipe, (char*)ppString[0], strlen((char*)ppString[0]));
ENDdoAction


BEGINparseSelectorAct
CODESTARTparseSelectorAct
CODE_STD_STRING_REQUESTparseSelectorAct(1)
	/* first check if this config line is actually for us */
	if(strncmp((char*) p, ":omprog:", sizeof(":omprog:") - 1)) {
		ABORT_FINALIZE(RS_RET_CONFLINE_UNPROCESSED);
	}

	/* ok, if we reach this point, we have something for us */
	p += sizeof(":omprog:") - 1; /* eat indicator sequence  (-1 because of '\0'!) */
	CHKiRet(createInstance(&pData));

	CHKmalloc(pData->szBinary = (uchar*) strdup((char*)szBinary));
	/* check if a non-standard template is to be applied */
	if(*(p-1) == ';')
		--p;
	CHKiRet(cflineParseTemplateName(&p, *ppOMSR, 0, 0, (uchar*) "RSYSLOG_FileFormat"));
CODE_STD_FINALIZERparseSelectorAct
ENDparseSelectorAct


BEGINmodExit
CODESTARTmodExit
	if(szBinary != NULL) {
		free(szBinary);
		szBinary = NULL;
	}
ENDmodExit


BEGINqueryEtryPt
CODESTARTqueryEtryPt
CODEqueryEtryPt_STD_OMOD_QUERIES
ENDqueryEtryPt



/* Reset config variables for this module to default values.
 */
static rsRetVal resetConfigVariables(uchar __attribute__((unused)) *pp, void __attribute__((unused)) *pVal)
{
	DEFiRet;

	if(szBinary != NULL) {
		free(szBinary);
		szBinary = NULL;
	}

	RETiRet;
}


BEGINmodInit()
CODESTARTmodInit
	*ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
CODEmodInit_QueryRegCFSLineHdlr
	CHKiRet(omsdRegCFSLineHdlr((uchar *)"actionomprogbinary", 0, eCmdHdlrGetWord, NULL, &szBinary, STD_LOADABLE_MODULE_ID));
	CHKiRet(omsdRegCFSLineHdlr((uchar *)"resetconfigvariables", 1, eCmdHdlrCustomHandler, resetConfigVariables, NULL, STD_LOADABLE_MODULE_ID));
CODEmodInit_QueryRegCFSLineHdlr
ENDmodInit

/* vi:set ai:
 */