/* imsolaris.c
 * This input module is used to gather local log data under Solaris. This
 * includes messages from local applications AS WELL AS the kernel log.
 * I first considered to make all of this available via imklog, but that
 * did not lock appropriately on second thought. So I created this module
 * that does anything for local message recption.
 *
 * This module is not meant to be used on plaforms other than Solaris. As
 * such, trying to compile it elswhere will probably fail with all sorts
 * of errors.
 *
 * Some notes on the Solaris syslog mechanism:
 * Both system (kernel) and application log messages are provided via
 * a single message stream.
 *
 * Solaris checks if the syslogd is running. If so, syslog() emits messages
 * to the log socket, only. Otherwise, it emits messages to the console.
 * It is possible to gather these console messages as well. However, then
 * we clutter the console.
 * Solaris does this "syslogd alive check" in a somewhat unexpected way
 * (at least unexpected for me): it uses the so-called "door" mechanism, a
 * fast RPC facility. I first thought that the door API was used to submit
 * the actual syslog messages. But this is not the case. Instead, a door
 * call is done, and the server process inside rsyslog simply does NOTHING
 * but return. All that Solaris sylsogd() is interested in is if the door
 * server (we) responds and thus can be considered alive. The actual message
 * is then submitted via the usual stream. I have to admit I do not
 * understand why the message itself is not passed via this high-performance
 * API. But anyhow, that's nothing I can change, so the most important thing
 * is to note how Solaris does this thing ;)
 * The syslog() library call checks syslogd state for *each* call (what a
 * waste of time...) and decides each time if the message should go to the
 * console or not.  According to OpenSolaris sources, it looks like there is
 * message loss potential when the door file is created before all data has
 * been pulled from the stream. While I have to admit that I do not fully
 * understand that problem, I will follow the original code advise and do
 * one complete pull cycle on the log socket (until it has no further data
 * available) and only thereafter create the door file and start the "regular"
 * pull cycle. As of my understanding, there is a minimal race between the
 * point where the initial pull cycle has ended and the door file is created,
 * but that race is also present in OpenSolaris syslogd code, so it should
 * not matter that much (plus, I do not know how to avoid it...)
 *
 * File begun on 2010-04-15 by RGerhards
 *
 * Copyright 2010 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 <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <assert.h>
#include <string.h>
#include <stropts.h>
#include <sys/strlog.h>
#include <errno.h>
#include "dirty.h"
#include "cfsysline.h"
#include "unicode-helper.h"
#include "module-template.h"
#include "srUtils.h"
#include "errmsg.h"
#include "net.h"
#include "glbl.h"
#include "msg.h"
#include "prop.h"
#include "sun_cddl.h"
#include "datetime.h"
#include "rsconf.h"

MODULE_TYPE_INPUT;
MODULE_TYPE_NOKEEP;
MODULE_CNFNAME("imsolaris")

/* defines */
#define PATH_LOG "/dev/log"


/* Module static data */
DEF_IMOD_STATIC_DATA;
DEFobjCurrIf(glbl) DEFobjCurrIf(prop) DEFobjCurrIf(datetime)


    /* config settings */
    struct modConfData_s {
    EMPTY_STRUCT;
};

static prop_t *pInputName = NULL; /* our inputName currently is always "imuxsock", and this will hold it */
static char *LogName = NULL; /* the log socket name TODO: make configurable! */


/* a function to replace the sun logerror() function.
 * It generates an error message from the supplied string. The main
 * reason for not calling logError directly is that sun_cddl.c does not
 * know or has acces to rsyslog objects (namely errmsg) -- and we do not
 * want to do this effort. -- rgerhards, 2010-04-19
 */
void imsolaris_logerror(int err, char *errStr) {
    LogError(err, RS_RET_ERR_DOOR, "%s", errStr);
}


/* we try to recover a failed file by closing and re-opening
 * it. We loop until the re-open works, but wait between each
 * failure. If the open succeeds, we assume all is well. If it is
 * not, we will run into the retry process with the next
 * iteration.
 * rgerhards, 2010-04-19
 */
static void tryRecover(void) {
    int tryNum = 1;
    int waitsecs;
    int waitusecs;
    rsRetVal iRet;

    close(sun_Pfd.fd);
    sun_Pfd.fd = -1;

    while (1) { /* loop broken inside */
        iRet = sun_openklog((LogName == NULL) ? PATH_LOG : LogName);
        if (iRet == RS_RET_OK) {
            if (tryNum > 1) {
                LogError(0, iRet, "failure on system log socket recovered.");
            }
            break;
        }
        /* failure, so sleep a bit. We wait try*10 ms, with a max of 15 seconds */
        if (tryNum == 1) {
            LogError(0, iRet, "failure on system log socket, trying to recover...");
        }
        waitusecs = tryNum * 10000;
        waitsecs = waitusecs / 1000000;
        DBGPRINTF("imsolaris: try %d to recover system log socket in %d.%d seconds\n", tryNum, waitsecs, waitusecs);
        if (waitsecs > 15) {
            waitsecs = 15;
            waitusecs = 0;
        } else {
            waitusecs = waitusecs % 1000000;
        }
        srSleep(waitsecs, waitusecs);
        ++tryNum;
    }
}


/* This function receives data from a socket indicated to be ready
 * to receive and submits the message received for processing.
 * rgerhards, 2007-12-20
 * Interface changed so that this function is passed the array index
 * of the socket which is to be processed. This eases access to the
 * growing number of properties. -- rgerhards, 2008-08-01
 */
static rsRetVal readLog(int fd, uchar *pRcv, int iMaxLine) {
    DEFiRet;
    struct strbuf data;
    struct strbuf ctl;
    struct log_ctl hdr;
    struct timeval tim;
    int flags;
    smsg_t *pMsg;
    int ret;
    char errStr[1024];

    data.buf = (char *)pRcv;
    data.maxlen = iMaxLine;
    ctl.maxlen = sizeof(struct log_ctl);
    ctl.buf = (caddr_t)&hdr;
    flags = 0;
    ret = getmsg(fd, &ctl, &data, &flags);
    if (ret < 0) {
        if (errno == EINTR) {
            FINALIZE;
        } else {
            int en = errno;
            rs_strerror_r(errno, errStr, sizeof(errStr));
            DBGPRINTF("imsolaris: stream input error on fd %d: %s.\n", fd, errStr);
            LogError(en, NO_ERRCODE, "imsolaris: stream input error: %s", errStr);
            tryRecover();
        }
    } else {
        DBGPRINTF("imsolaris: message from log stream %d: %s\n", fd, pRcv);
        pRcv[data.len] = '\0'; /* make sure it is a valid C-String */
        CHKiRet(msgConstruct(&pMsg));
        MsgSetInputName(pMsg, pInputName);
        MsgSetRawMsg(pMsg, (char *)pRcv, strlen((char *)pRcv));
        MsgSetHOSTNAME(pMsg, glbl.GetLocalHostName(), ustrlen(glbl.GetLocalHostName()));
        msgSetPRI(pMsg, hdr.pri);
        pMsg->msgFlags = NEEDS_PARSING | NO_PRI_IN_RAW | IGNDATE;

        /* Construct timestamp from msg ctl struct */
        tim.tv_usec = 0;
        tim.tv_sec = hdr.ttime;
        datetime.timeval2syslogTime(&tim, &pMsg->tRcvdAt, TIME_IN_LOCALTIME);
        CHKiRet(submitMsg(pMsg));
    }

finalize_it:
    RETiRet;
}


/* once the system is fully initialized, we wait for new messages.
 * We may think about replacing this with a read-loop, thus saving
 * us the overhead of the poll.
 * The timeout variable is the timeout to use for poll. During startup,
 * it should be set to 0 (non-blocking) and later to -1 (infinit, blocking).
 * This mimics the (strange) behaviour of the original syslogd.
 * rgerhards, 2010-04-19
 */
static rsRetVal getMsgs(thrdInfo_t *pThrd, int timeout) {
    DEFiRet;
    int nfds;
    int iMaxLine;
    uchar *pRcv = NULL; /* receive buffer */
    uchar bufRcv[4096 + 1];
    char errStr[1024];

    iMaxLine = glbl.GetMaxLine(runConf);

    /* we optimize performance: if iMaxLine is below 4K (which it is in almost all
     * cases, we use a fixed buffer on the stack. Only if it is higher, heap memory
     * is used. We could use alloca() to achive a similar aspect, but there are so
     * many issues with alloca() that I do not want to take that route.
     * rgerhards, 2008-09-02
     */
    if ((size_t)iMaxLine < sizeof(bufRcv) - 1) {
        pRcv = bufRcv;
    } else {
        CHKmalloc(pRcv = (uchar *)malloc(iMaxLine + 1));
    }

    while (pThrd->bShallStop != RSTRUE) {
        DBGPRINTF("imsolaris: waiting for next message (timeout %d)...\n", timeout);
        if (timeout == 0) {
            nfds = poll(&sun_Pfd, 1, timeout); /* wait without timeout */

            if (pThrd->bShallStop == RSTRUE) {
                break;
            }

            if (nfds == 0) {
                if (timeout == 0) {
                    DBGPRINTF("imsolaris: no more messages, getMsgs() terminates\n");
                    FINALIZE;
                } else {
                    continue;
                }
            }

            if (nfds < 0) {
                if (errno != EINTR) {
                    int en = errno;
                    rs_strerror_r(en, errStr, sizeof(errStr));
                    DBGPRINTF("imsolaris: poll error: %d = %s.\n", errno, errStr);
                    LogError(en, NO_ERRCODE, "imsolaris: poll error: %s", errStr);
                }
                continue;
            }
            if (sun_Pfd.revents & POLLIN) {
                readLog(sun_Pfd.fd, pRcv, iMaxLine);
            } else if (sun_Pfd.revents & (POLLNVAL | POLLHUP | POLLERR)) {
                tryRecover();
            }
        } else {
            /* if we have an infinite wait, we do not use poll at all
             * I'd consider this a waste of time. However, I do not totally
             * remove the code, as it may be useful if we decide at some
             * point to provide a capability to support multiple input streams
             * at once (this may be useful for a jail). In that case, the poll()
             * loop would be needed, and so it doesn't make much sense to change
             * the code to not support it. -- rgerhards, 2010-04-20
             */
            readLog(sun_Pfd.fd, pRcv, iMaxLine);
        }
    }

finalize_it:
    if (pRcv != NULL && (size_t)iMaxLine >= sizeof(bufRcv) - 1) free(pRcv);

    RETiRet;
}


BEGINbeginCnfLoad
    CODESTARTbeginCnfLoad;
ENDbeginCnfLoad


BEGINendCnfLoad
    CODESTARTendCnfLoad;
ENDendCnfLoad


BEGINcheckCnf
    CODESTARTcheckCnf;
ENDcheckCnf


BEGINactivateCnf
    CODESTARTactivateCnf;
ENDactivateCnf


BEGINfreeCnf
    CODESTARTfreeCnf;
ENDfreeCnf


/* This function is called to gather input. */
BEGINrunInput
    CODESTARTrunInput;
    /* this is an endless loop - it is terminated when the thread is
     * signalled to do so. This, however, is handled by the framework,
     * right into the sleep below.
     */

    DBGPRINTF("imsolaris: doing startup poll before openeing door()\n");
    CHKiRet(getMsgs(pThrd, 0));

    /* note: sun's syslogd code claims that the door should only
     * be opened when the log stream has been polled. So file header
     * comment of this file for more details.
     */
    sun_open_door();
    DBGPRINTF("imsolaris: starting regular poll loop\n");
    iRet = getMsgs(pThrd, -1); /* this is the primary poll loop, infinite timeout */

    DBGPRINTF("imsolaris: terminating (bShallStop=%d)\n", pThrd->bShallStop);
finalize_it:
    RETiRet;
ENDrunInput


BEGINwillRun
    CODESTARTwillRun;
    /* we need to create the inputName property (only once during our lifetime) */
    CHKiRet(prop.Construct(&pInputName));
    CHKiRet(prop.SetString(pInputName, UCHAR_CONSTANT("imsolaris"), sizeof("imsolaris") - 1));
    CHKiRet(prop.ConstructFinalize(pInputName));

    iRet = sun_openklog((LogName == NULL) ? PATH_LOG : LogName);
    if (iRet != RS_RET_OK) {
        LogError(0, iRet, "error opening system log socket");
    }
finalize_it:
ENDwillRun


BEGINafterRun
    CODESTARTafterRun;
    /* do cleanup here */
    if (pInputName != NULL) prop.Destruct(&pInputName);
    free(LogName);
ENDafterRun


BEGINmodExit
    CODESTARTmodExit;
    sun_delete_doorfiles();
    objRelease(glbl, CORE_COMPONENT);
    objRelease(prop, CORE_COMPONENT);
    objRelease(datetime, CORE_COMPONENT);
ENDmodExit


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


BEGINqueryEtryPt
    CODESTARTqueryEtryPt;
    CODEqueryEtryPt_STD_IMOD_QUERIES;
    CODEqueryEtryPt_IsCompatibleWithFeature_IF_OMOD_QUERIES;
ENDqueryEtryPt

static rsRetVal resetConfigVariables(uchar __attribute__((unused)) * pp, void __attribute__((unused)) * pVal) {
    return RS_RET_OK;
}


BEGINmodInit()
    CODESTARTmodInit;
    *ipIFVersProvided = CURR_MOD_IF_VERSION; /* we only support the current interface specification */
    CODEmodInit_QueryRegCFSLineHdlr CHKiRet(objUse(glbl, CORE_COMPONENT));
    CHKiRet(objUse(prop, CORE_COMPONENT));
    CHKiRet(objUse(datetime, CORE_COMPONENT));

    DBGPRINTF("imsolaris version %s initializing\n", PACKAGE_VERSION);

    /* register config file handlers */
    CHKiRet(omsdRegCFSLineHdlr((uchar *)"resetconfigvariables", 1, eCmdHdlrCustomHandler, resetConfigVariables, NULL,
                               STD_LOADABLE_MODULE_ID));
    CHKiRet(omsdRegCFSLineHdlr((uchar *)"imsolarislogsocketname", 0, eCmdHdlrGetWord, NULL, &LogName,
                               STD_LOADABLE_MODULE_ID));
ENDmodInit
/* vim:set ai:
 */
