/* ompgsql.c
 * This is the implementation of the build-in output module for PgSQL.
 *
 * NOTE: read comments in module-template.h to understand how this file
 *       works!
 *
 * File begun on 2007-10-18 by sur5r (converted from ommysql.c)
 *
 * Copyright 2007-2018 Rainer Gerhards and Adiscon GmbH.
 *
 * The following link my be useful for the not-so-postgres literate
 * when setting up a test environment (on Fedora):
 * http://www.jboss.org/community/wiki/InstallPostgreSQLonFedora
 *
 * 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 <time.h>
#include <netdb.h>
#include <libpq-fe.h>
#include "conf.h"
#include "syslogd-types.h"
#include "srUtils.h"
#include "template.h"
#include "module-template.h"
#include "errmsg.h"
#include "parserif.h"

MODULE_TYPE_OUTPUT;
MODULE_TYPE_NOKEEP;
MODULE_CNFNAME("ompgsql")


/* internal structures
 */
DEF_OMOD_STATIC_DATA;

typedef struct _instanceData {
    char srv[MAXHOSTNAMELEN + 1]; /* IP or hostname of DB server*/
    char dbname[_DB_MAXDBLEN + 1]; /* DB name */
    char user[_DB_MAXUNAMELEN + 1]; /* DB user */
    char pass[_DB_MAXPWDLEN + 1]; /* DB user's password */
    char conninfo[_DB_MAXCONNINFOLEN + 1]; /* Connection parameters or URI */
    unsigned int trans_age;
    unsigned int trans_commit;
    unsigned short multi_row;
    int port;
    uchar *tpl; /* format template to use */
} instanceData;

typedef struct wrkrInstanceData {
    instanceData *pData;
    PGconn *f_hpgsql; /* handle to PgSQL */
    ConnStatusType eLastPgSQLStatus; /* last status from postgres */
} wrkrInstanceData_t;

/* action (instance) parameters */
static struct cnfparamdescr actpdescr[] = {
    {"server", eCmdHdlrGetWord, 0},  {"db", eCmdHdlrGetWord, 0},     {"user", eCmdHdlrGetWord, 0},
    {"uid", eCmdHdlrGetWord, 0},     {"pass", eCmdHdlrGetWord, 0},   {"pwd", eCmdHdlrGetWord, 0},
    {"multirows", eCmdHdlrInt, 0},   {"trans_size", eCmdHdlrInt, 0}, {"trans_age", eCmdHdlrInt, 0},
    {"serverport", eCmdHdlrInt, 0},  {"port", eCmdHdlrInt, 0},       {"template", eCmdHdlrGetWord, 0},
    {"conninfo", eCmdHdlrGetWord, 0}};


static struct cnfparamblk actpblk = {CNFPARAMBLK_VERSION, sizeof(actpdescr) / sizeof(struct cnfparamdescr), actpdescr};


BEGINinitConfVars /* (re)set config variables to default values */
    CODESTARTinitConfVars;
ENDinitConfVars


static rsRetVal writePgSQL(uchar *psz, wrkrInstanceData_t *pData);

BEGINcreateInstance
    CODESTARTcreateInstance;
ENDcreateInstance

BEGINcreateWrkrInstance
    CODESTARTcreateWrkrInstance;
    pWrkrData->f_hpgsql = NULL;
ENDcreateWrkrInstance


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


/* The following function is responsible for closing a
 * PgSQL connection.
 */
static void closePgSQL(wrkrInstanceData_t *pWrkrData) {
    assert(pWrkrData != NULL);

    if (pWrkrData->f_hpgsql != NULL) { /* just to be on the safe side... */
        PQfinish(pWrkrData->f_hpgsql);
        pWrkrData->f_hpgsql = NULL;
    }
}

BEGINfreeInstance
    CODESTARTfreeInstance;
    free(pData->tpl);
ENDfreeInstance

BEGINfreeWrkrInstance
    CODESTARTfreeWrkrInstance;
    closePgSQL(pWrkrData);
ENDfreeWrkrInstance

BEGINdbgPrintInstInfo
    CODESTARTdbgPrintInstInfo;
    /* nothing special here */
ENDdbgPrintInstInfo


/* log a database error with descriptive message.
 * We check if we have a valid handle. If not, we simply
 * report an error, but can not be specific. RGerhards, 2007-01-30
 */
static void reportDBError(wrkrInstanceData_t *pWrkrData, int bSilent) {
    char errMsg[512];
    ConnStatusType ePgSQLStatus;

    assert(pWrkrData != NULL);
    bSilent = 0;

    /* output log message */
    errno = 0;
    if (pWrkrData->f_hpgsql == NULL) {
        LogError(0, NO_ERRCODE, "unknown DB error occurred - could not obtain PgSQL handle");
    } else { /* we can ask pgsql for the error description... */
        ePgSQLStatus = PQstatus(pWrkrData->f_hpgsql);
        snprintf(errMsg, sizeof(errMsg), "db error (%d): %s\n", ePgSQLStatus, PQerrorMessage(pWrkrData->f_hpgsql));
        if (bSilent || ePgSQLStatus == pWrkrData->eLastPgSQLStatus)
            dbgprintf("pgsql, DBError(silent): %s\n", errMsg);
        else {
            pWrkrData->eLastPgSQLStatus = ePgSQLStatus;
            LogError(0, NO_ERRCODE, "%s", errMsg);
        }
    }

    return;
}


/* The following function is responsible for initializing a
 * PgSQL connection.
 */
static rsRetVal initPgSQL(wrkrInstanceData_t *pWrkrData, int bSilent) {
    int sslStatus;
    instanceData *pData;
    DEFiRet;

    pData = pWrkrData->pData;
    assert(pData != NULL);
    assert(pWrkrData->f_hpgsql == NULL);

    if (strlen(pData->conninfo) > 0) {
        /* Don't log the whole connection string, because it contains the DB password */
        dbgprintf("initPgSQL: using connection string provided by conninfo\n");
        pWrkrData->f_hpgsql = PQconnectdb(pData->conninfo);
    } else {
        dbgprintf("initPgSQL: host=%s port=%d dbname=%s uid=%s\n", pData->srv, pData->port, pData->dbname, pData->user);

        /* Force PostgreSQL to use ANSI-SQL conforming strings, otherwise we may
         * get all sorts of side effects (e.g.: backslash escapes) and warnings
         *
         * Note: PostgreSQL versions since 9.3 have this already on by default.
         */
        const char *PgConnectionOptions = "-c standard_conforming_strings=on";

        /* Connect to database */
        char port[6];
        snprintf(port, sizeof(port), "%d", pData->port);

        pWrkrData->f_hpgsql =
            PQsetdbLogin(pData->srv, port, PgConnectionOptions, NULL, pData->dbname, pData->user, pData->pass);
    }

    if (pWrkrData->f_hpgsql == NULL) {
        reportDBError(pWrkrData, bSilent);
        closePgSQL(pWrkrData); /* ignore any error we may get */
        iRet = RS_RET_SUSPENDED;
    }

#ifdef HAVE_PGSSLINUSE
    sslStatus = PQsslInUse(pWrkrData->f_hpgsql);
#else
    sslStatus = PQgetssl(pWrkrData->f_hpgsql) == NULL ? 0 : 1;
#endif
    dbgprintf("initPgSQL: ssl status: %d\n", sslStatus);

    RETiRet;
}


/* try the insert into postgres and return if that failed or not
 * (1 = had error, 0=ok). We do not use the standard IRET calling convention
 * rgerhards, 2009-04-17
 */
static int tryExec(uchar *pszCmd, wrkrInstanceData_t *pWrkrData) {
    PGresult *pgRet;
    ExecStatusType execState;
    int bHadError = 0;

    /* try insert */
    pgRet = PQexec(pWrkrData->f_hpgsql, (char *)pszCmd);
    execState = PQresultStatus(pgRet);
    if (execState != PGRES_COMMAND_OK && execState != PGRES_TUPLES_OK) {
        // complain a lot in case any issues with DB communication
        LogError(0, execState, "postgres query execution failed: %s", PQresStatus(PQresultStatus(pgRet)));
        bHadError = 1;
    }
    PQclear(pgRet);

    return (bHadError);
}


/* The following function writes the current log entry
 * to an established PgSQL session.
 * Enhanced function to take care of the returned error
 * value (if there is such). Note that this may happen due to
 * a sql format error - connection aborts were properly handled
 * before my patch. -- rgerhards, 2009-04-17
 */
static rsRetVal writePgSQL(uchar *psz, wrkrInstanceData_t *pWrkrData) {
    int bHadError = 0;
    DEFiRet;

    assert(psz != NULL);
    assert(pWrkrData != NULL);

    dbgprintf("writePgSQL: %s\n", psz);

    bHadError = tryExec(psz, pWrkrData); /* try insert */

    if (bHadError || (PQstatus(pWrkrData->f_hpgsql) != CONNECTION_OK)) {
#if 0 /* re-enable once we have transaction support */
		/* error occurred, try to re-init connection and retry */
		int inTransaction = 0;
		if(pData->f_hpgsql != NULL) {
			PGTransactionStatusType xactStatus = PQtransactionStatus(pData->f_hpgsql);
			if((xactStatus == PQTRANS_INTRANS) || (xactStatus == PQTRANS_ACTIVE)) {
				inTransaction = 1;
			}
		}
		if ( inTransaction == 0 )
#endif
        {
            closePgSQL(pWrkrData); /* close the current handle */
            CHKiRet(initPgSQL(pWrkrData, 0)); /* try to re-open */
            bHadError = tryExec(psz, pWrkrData); /* retry */
        }
        if (bHadError || (PQstatus(pWrkrData->f_hpgsql) != CONNECTION_OK)) {
            /* we failed, giving up for now */
            reportDBError(pWrkrData, 0);
            closePgSQL(pWrkrData); /* free ressources */
            ABORT_FINALIZE(RS_RET_SUSPENDED);
        }
    }

finalize_it:
    if (iRet == RS_RET_OK) {
        pWrkrData->eLastPgSQLStatus = CONNECTION_OK; /* reset error for error supression */
    }

    RETiRet;
}


BEGINtryResume
    CODESTARTtryResume;
    if (pWrkrData->f_hpgsql == NULL) {
        iRet = initPgSQL(pWrkrData, 1);
        if (iRet == RS_RET_OK) {
            /* the code above seems not to actually connect to the database. As such, we do a
             * dummy statement (a pointless select...) to verify the connection and return
             * success only when that statemetn succeeds. Note that I am far from being a
             * PostgreSQL expert, so any patch that does the desired result in a more
             * intelligent way is highly welcome. -- rgerhards, 2009-12-16
             */
            iRet = writePgSQL((uchar *)"select 'a' as a", pWrkrData);
        }
    }
ENDtryResume


BEGINbeginTransaction
    CODESTARTbeginTransaction;
ENDbeginTransaction


BEGINcommitTransaction
    CODESTARTcommitTransaction;
    dbgprintf("ompgsql: beginTransaction\n");
    if (pWrkrData->f_hpgsql == NULL) initPgSQL(pWrkrData, 0);
    CHKiRet(writePgSQL((uchar *)"BEGIN", pWrkrData)); /* TODO: make user-configurable */

    for (unsigned i = 0; i < nParams; ++i) {
        iRet = writePgSQL(actParam(pParams, 1, i, 0).param, pWrkrData);
        if (iRet != RS_RET_OK && iRet != RS_RET_DEFER_COMMIT && iRet != RS_RET_PREVIOUS_COMMITTED) {
            // in case of any error lets retry, writePgSQL should return
            // iRet = RS_RET_SUSPENDED and we need return it downstream, otherwise
            // messages gonna be lost
            LogError(0, iRet, "Failed too execute PG query. Message suspended.");

            // since writePgSQL may close connection in case of errors
            // no point to issue rollback on new connection
            // writePgSQL((uchar*) "ROLLBACK", pWrkrData);

            // To be on safe side lets kill connection similar to what
            // ommysql plugin does.
            closePgSQL(pWrkrData);
            // signal mod.om.beginTransaction that we want retry
            ABORT_FINALIZE(iRet);
        }
    }

    CHKiRet(writePgSQL((uchar *)"COMMIT", pWrkrData)); /* TODO: make user-configurable */

finalize_it:
    if (iRet == RS_RET_OK) {
        pWrkrData->eLastPgSQLStatus = CONNECTION_OK; /* reset error for error supression */
    }

ENDcommitTransaction


static inline void setInstParamDefaults(instanceData *pData) {
    pData->tpl = NULL;
    pData->multi_row = 100;
    pData->trans_commit = 100;
    pData->trans_age = 60;
    pData->port = 5432;
    strcpy(pData->user, "postgres");
    strcpy(pData->pass, "postgres");
}

BEGINnewActInst
    struct cnfparamvals *pvals;
    int i;
    char *cstr;
    size_t len;
    CODESTARTnewActInst;
    if ((pvals = nvlstGetParams(lst, &actpblk, NULL)) == NULL) {
        ABORT_FINALIZE(RS_RET_MISSING_CNFPARAMS);
    }

    CHKiRet(createInstance(&pData));
    setInstParamDefaults(pData);

    CODE_STD_STRING_REQUESTparseSelectorAct(1) for (i = 0; i < actpblk.nParams; ++i) {
        if (!pvals[i].bUsed) continue;
        if (!strcmp(actpblk.descr[i].name, "server")) {
            cstr = es_str2cstr(pvals[i].val.d.estr, NULL);
            len = es_strlen(pvals[i].val.d.estr);
            if (len >= sizeof(pData->srv) - 1) {
                parser_errmsg(
                    "ompgsql: srv parameter longer than supported "
                    "maximum of %d characters",
                    (int)sizeof(pData->srv) - 1);
                ABORT_FINALIZE(RS_RET_PARAM_ERROR);
            }
            memcpy(pData->srv, cstr, len + 1);
            free(cstr);
        } else if (!strcmp(actpblk.descr[i].name, "port")) {
            pData->port = (int)pvals[i].val.d.n;
        } else if (!strcmp(actpblk.descr[i].name, "serverport")) {
            pData->port = (int)pvals[i].val.d.n;
        } else if (!strcmp(actpblk.descr[i].name, "multirows")) {
            pData->multi_row = (int)pvals[i].val.d.n;
        } else if (!strcmp(actpblk.descr[i].name, "trans_size")) {
            pData->trans_commit = (int)pvals[i].val.d.n;
        } else if (!strcmp(actpblk.descr[i].name, "trans_age")) {
            pData->trans_age = (int)pvals[i].val.d.n;
        } else if (!strcmp(actpblk.descr[i].name, "db")) {
            cstr = es_str2cstr(pvals[i].val.d.estr, NULL);
            len = es_strlen(pvals[i].val.d.estr);
            if (len >= sizeof(pData->dbname) - 1) {
                parser_errmsg(
                    "ompgsql: db parameter longer than supported "
                    "maximum of %d characters",
                    (int)sizeof(pData->dbname) - 1);
                ABORT_FINALIZE(RS_RET_PARAM_ERROR);
            }
            memcpy(pData->dbname, cstr, len + 1);
            free(cstr);
        } else if (!strcmp(actpblk.descr[i].name, "user") || !strcmp(actpblk.descr[i].name, "uid")) {
            cstr = es_str2cstr(pvals[i].val.d.estr, NULL);
            len = es_strlen(pvals[i].val.d.estr);
            if (len >= sizeof(pData->user) - 1) {
                parser_errmsg(
                    "ompgsql: user/uid parameter longer than supported "
                    "maximum of %d characters",
                    (int)sizeof(pData->user) - 1);
                ABORT_FINALIZE(RS_RET_PARAM_ERROR);
            }
            memcpy(pData->user, cstr, len + 1);
            free(cstr);
        } else if (!strcmp(actpblk.descr[i].name, "pass") || !strcmp(actpblk.descr[i].name, "pwd")) {
            cstr = es_str2cstr(pvals[i].val.d.estr, NULL);
            len = es_strlen(pvals[i].val.d.estr);
            if (len >= sizeof(pData->pass) - 1) {
                parser_errmsg(
                    "ompgsql: pass/pwd parameter longer than supported "
                    "maximum of %d characters",
                    (int)sizeof(pData->pass) - 1);
                ABORT_FINALIZE(RS_RET_PARAM_ERROR);
            }
            memcpy(pData->pass, cstr, len + 1);
            free(cstr);
        } else if (!strcmp(actpblk.descr[i].name, "template")) {
            pData->tpl = (uchar *)es_str2cstr(pvals[i].val.d.estr, NULL);
        } else if (!strcmp(actpblk.descr[i].name, "conninfo")) {
            cstr = es_str2cstr(pvals[i].val.d.estr, NULL);
            len = es_strlen(pvals[i].val.d.estr);
            if (len >= sizeof(pData->conninfo) - 1) {
                parser_errmsg(
                    "ompgsql: conninfo parameter longer than supported "
                    "maximum of %d characters",
                    (int)sizeof(pData->conninfo) - 1);
                ABORT_FINALIZE(RS_RET_PARAM_ERROR);
            }
            memcpy(pData->conninfo, cstr, len + 1);
            free(cstr);
        } else {
            dbgprintf(
                "ompgsql: program error, non-handled "
                "param '%s'\n",
                actpblk.descr[i].name);
        }
    }

    if (strlen(pData->conninfo) == 0 && (strlen(pData->srv) == 0 || strlen(pData->dbname) == 0)) {
        parser_errmsg("ompgsql: must provide conninfo or server and dbname");
        ABORT_FINALIZE(RS_RET_MISSING_CNFPARAMS);
    }

    if (pData->tpl == NULL) {
        CHKiRet(OMSRsetEntry(*ppOMSR, 0, (uchar *)strdup(" StdPgSQLFmt"), OMSR_RQD_TPL_OPT_SQL));
    } else {
        CHKiRet(OMSRsetEntry(*ppOMSR, 0, (uchar *)strdup((char *)pData->tpl), OMSR_RQD_TPL_OPT_SQL));
    }

    CODE_STD_FINALIZERnewActInst;
    cnfparamvalsDestruct(pvals, &actpblk);
ENDnewActInst

BEGINparseSelectorAct
    int iPgSQLPropErr = 0;
    CODESTARTparseSelectorAct;
    CODE_STD_STRING_REQUESTparseSelectorAct(1)
        /* first check if this config line is actually for us
         * The first test [*p == '>'] can be skipped if a module shall only
         * support the newer slection syntax [:modname:]. This is in fact
         * recommended for new modules. Please note that over time this part
         * will be handled by rsyslogd itself, but for the time being it is
         * a good compromise to do it at the module level.
         * rgerhards, 2007-10-15
         */

        if (!strncmp((char *)p, ":ompgsql:", sizeof(":ompgsql:") - 1)) p +=
        sizeof(":ompgsql:") - 1; /* eat indicator sequence (-1 because of '\0'!) */
    else ABORT_FINALIZE(RS_RET_CONFLINE_UNPROCESSED);

    /* ok, if we reach this point, we have something for us */
    if ((iRet = createInstance(&pData)) != RS_RET_OK) goto finalize_it;
    setInstParamDefaults(pData);

    /* sur5r 2007-10-18: added support for PgSQL
     * :ompgsql:server,dbname,userid,password
     * Now we read the PgSQL connection properties
     * and verify that the properties are valid.
     */
    if (getSubString(&p, pData->srv, MAXHOSTNAMELEN + 1, ',')) iPgSQLPropErr++;
    dbgprintf("%p:%s\n", p, p);
    if (*pData->srv == '\0') iPgSQLPropErr++;
    if (getSubString(&p, pData->dbname, _DB_MAXDBLEN + 1, ',')) iPgSQLPropErr++;
    if (*pData->dbname == '\0') iPgSQLPropErr++;
    if (getSubString(&p, pData->user, _DB_MAXUNAMELEN + 1, ',')) iPgSQLPropErr++;
    if (*pData->user == '\0') iPgSQLPropErr++;
    if (getSubString(&p, pData->pass, _DB_MAXPWDLEN + 1, ';')) iPgSQLPropErr++;
    /* now check for template
     * We specify that the SQL option must be present in the template.
     * This is for your own protection (prevent sql injection).
     */
    if (*(p - 1) == ';') {
        p--;
        CHKiRet(cflineParseTemplateName(&p, *ppOMSR, 0, OMSR_RQD_TPL_OPT_SQL, (uchar *)pData->tpl));
    } else {
        CHKiRet(cflineParseTemplateName(&p, *ppOMSR, 0, OMSR_RQD_TPL_OPT_SQL, (uchar *)" StdPgSQLFmt"));
    }

    /* If we detect invalid properties, we disable logging,
     * because right properties are vital at this place.
     * Retries make no sense.
     */
    if (iPgSQLPropErr) {
        LogError(0, RS_RET_INVALID_PARAMS,
                 "Trouble with PgSQL connection properties. "
                 "-PgSQL logging disabled");
        ABORT_FINALIZE(RS_RET_INVALID_PARAMS);
    }

    CODE_STD_FINALIZERparseSelectorAct
ENDparseSelectorAct

BEGINmodExit
    CODESTARTmodExit;
ENDmodExit


BEGINqueryEtryPt
    CODESTARTqueryEtryPt;
    CODEqueryEtryPt_STD_OMODTX_QUERIES;
    CODEqueryEtryPt_STD_OMOD8_QUERIES;
    CODEqueryEtryPt_STD_CONF2_OMOD_QUERIES;
/* CODEqueryEtryPt_TXIF_OMOD_QUERIES currently no TX support! */ /* we support the transactional interface! */
ENDqueryEtryPt


BEGINmodInit()
    CODESTARTmodInit;
    INITLegCnfVars;
    *ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
    CODEmodInit_QueryRegCFSLineHdlr INITChkCoreFeature(bCoreSupportsBatching, CORE_FEATURE_BATCHING);
    if (!bCoreSupportsBatching) {
        LogError(0, NO_ERRCODE, "ompgsql: rsyslog core too old");
        ABORT_FINALIZE(RS_RET_ERR);
    }
ENDmodInit

/* vi:set ai: */