/* $Id: symux.c,v 1.30 2004/02/26 22:48:08 dijkstra Exp $ */

/*
 * Copyright (c) 2001-2004 Willem Dijkstra
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *    - Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    - Redistributions in binary form must reproduce the above
 *      copyright notice, this list of conditions and the following
 *      disclaimer in the documentation and/or other materials provided
 *      with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <netdb.h>

#include <machine/endian.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sysexits.h>
#include <syslog.h>
#include <unistd.h>
#include <rrd.h>

#include "data.h"
#include "error.h"
#include "limits.h"
#include "symux.h"
#include "symuxnet.h"
#include "net.h"
#include "readconf.h"
#include "share.h"
#include "xmalloc.h"

__BEGIN_DECLS
void exithandler();
void huphandler(int);
void signalhandler(int);
__END_DECLS

int flag_hup = 0;
fd_set fdset;
int maxfd;

void
exithandler(int s)
{
    info("received signal %d - quitting", s);
    exit(EX_TEMPFAIL);
}
void
huphandler(int s)
{
    info("hup received");
    flag_hup = 1;
}
/*
 * symux is the receiver of symon performance measurements.
 *
 * The main goals symon hopes to accomplish is:
 * - to take fine grained measurements of system parameters
 * - with minimal performance impact
 * - in a secure way.
 *
 * Measuring system parameters (e.g. interfaces) sometimes means traversing
 * lists in kernel memory. Because of this the measurement of data has been
 * decoupled from the processing and storage of data. Storing the measured
 * information that symon provides is done by a second program, called symux.
 *
 * Symon can keep track of cpu, memory, disk and network interface
 * interactions. Symon was built specifically for OpenBSD.
 */
int
main(int argc, char *argv[])
{
    struct symonpacket packet;
    struct packedstream ps;
    char *cfgfile;
    char *cfgpath;
    char *stringbuf;
    char *stringptr;
    int maxstringlen;
    struct muxlist mul, newmul;
    char *arg_ra[4];
    struct stream *stream;
    struct source *source;
    struct mux *mux;
    FILE *f;
    int ch;
    int offset;
    time_t timestamp;
    int churnbuflen;

    SLIST_INIT(&mul);

    /* reset flags */
    flag_debug = 0;
    flag_daemon = 0;
    cfgfile = SYMUX_CONFIG_FILE;

    while ((ch = getopt(argc, argv, "dvf:")) != -1) {
	switch (ch) {
	case 'd':
	    flag_debug = 1;
	    break;
	case 'f':
	    if (optarg && optarg[0] != '/') {
		/* cfg path needs to be absolute, we will be a daemon soon */
		cfgpath = xmalloc(MAXPATHLEN);
		if ((cfgpath = getcwd(cfgpath, MAXPATHLEN)) == NULL)
		    fatal("could not get working directory");

		maxstringlen = strlen(cfgpath) + strlen(optarg) + 1;
		cfgfile = xmalloc(maxstringlen);
		strncpy(cfgfile, cfgpath, maxstringlen);
		stringptr = cfgfile + strlen(cfgpath);
		stringptr[0] = '/';
		stringptr++;
		strncpy(stringptr, optarg, maxstringlen - (cfgfile - stringptr));
		cfgfile[maxstringlen] = '\0';

		free(cfgpath);
	    } else
		cfgfile = xstrdup(optarg);

	    break;
	case 'v':
	    info("symux version %s", SYMUX_VERSION);
	default:
	    info("usage: %s [-d] [-v] [-f cfgfile]", __progname);
	    exit(EX_USAGE);
	}
    }

    /* parse configuration file */
    if (!read_config_file(&mul, cfgfile))
	fatal("configuration contained errors; quitting");

    setegid(getgid());
    setgid(getgid());

    if (flag_debug != 1) {
	if (daemon(0, 0) != 0)
	    fatal("daemonize failed");

	flag_daemon = 1;

	/* record pid */
	f = fopen(SYMUX_PID_FILE, "w");
	if (f) {
	    fprintf(f, "%u\n", (u_int) getpid());
	    fclose(f);
	}
    }

    info("symux version %s", SYMUX_VERSION);

    if (flag_debug == 1)
	info("program id=%d", (u_int) getpid());

    mux = SLIST_FIRST(&mul);

    churnbuflen = calculate_churnbuffer(&mux->sol);
    debug("size of churnbuffer = %d", churnbuflen);
    initshare(churnbuflen);

    /* catch signals */
    signal(SIGHUP, huphandler);
    signal(SIGINT, exithandler);
    signal(SIGQUIT, exithandler);
    signal(SIGTERM, exithandler);
    signal(SIGTERM, exithandler);

    /* prepare crc32 */
    init_crc32();

    /* prepare sockets */
    if (get_symon_sockets(mux) == 0)
	fatal("no sockets could be opened for incoming symon traffic");
    if (get_client_socket(mux) == 0)
	fatal("socket for client connections could not be opened");

    /* main loop */
    for (;;) {			/* FOREVER */
	wait_for_traffic(mux, &source, &packet);

	if (flag_hup == 1) {
	    flag_hup = 0;

	    SLIST_INIT(&newmul);

	    if (!read_config_file(&newmul, cfgfile)) {
		info("new configuration contains errors; keeping old configuration");
		free_muxlist(&newmul);
	    } else {
		info("read configuration file '%.100s' successfully", cfgfile);
		free_muxlist(&mul);
		mul = newmul;
		mux = SLIST_FIRST(&mul);
		get_symon_sockets(mux);
		get_client_socket(mux);
	    }
	} else {

	    /*
	     * Put information from packet into stringbuf (shared region).
	     * Note that the stringbuf is used twice: 1) to update the
	     * rrdfile and 2) to collect all the data from a single packet
	     * that needs to shared to the clients. This is the reason for
	     * the hasseling with stringptr.
	     */

	    offset = mux->offset;
	    maxstringlen = shared_getmaxlen();
	    /* put time:ip: into shared region */
	    master_forbidread();
	    timestamp = (time_t) packet.header.timestamp;
	    stringbuf = (char *) shared_getmem();
	    snprintf(stringbuf, maxstringlen, "%s;", source->addr);

	    /* hide this string region from rrd update */
	    maxstringlen -= strlen(stringbuf);
	    stringptr = stringbuf + strlen(stringbuf);

	    while (offset < packet.header.length) {
		bzero(&ps, sizeof(struct packedstream));
		offset += sunpack(packet.data + offset, &ps);

		/* find stream in source */
		stream = find_source_stream(source, ps.type, ps.args);

		if (stream != NULL) {
		    /* put type in and hide from rrd */
		    snprintf(stringptr, maxstringlen, "%s:", type2str(ps.type));
		    maxstringlen -= strlen(stringptr);
		    stringptr += strlen(stringptr);
		    /* put arguments in and hide from rrd */
		    snprintf(stringptr, maxstringlen, "%s:",
			     ((ps.args == NULL) ? "0" : ps.args));
		    maxstringlen -= strlen(stringptr);
		    stringptr += strlen(stringptr);
		    /* put timestamp in and show to rrd */
		    snprintf(stringptr, maxstringlen, "%u", timestamp);
		    arg_ra[3] = stringptr;
		    maxstringlen -= strlen(stringptr);
		    stringptr += strlen(stringptr);

		    /* put measurements in */
		    ps2strn(&ps, stringptr, maxstringlen, PS2STR_RRD);

		    if (stream->file != NULL) {
			/* clear optind for getopt call by rrdupdate */
			optind = 0;
			/* save if file specified */
			arg_ra[0] = "rrdupdate";
			arg_ra[1] = "--";
			arg_ra[2] = stream->file;

			/*
			 * This call will cost a lot (symux will become
			 * unresponsive and eat up massive amounts of cpu) if
			 * the rrdfile is out of sync.
			 */
			rrd_update(4, arg_ra);

			if (rrd_test_error()) {
			    warning("rrd_update:%.200s", rrd_get_error());
			    warning("%.200s %.200s %.200s %.200s", arg_ra[0], arg_ra[1],
				    arg_ra[2], arg_ra[3]);
			    rrd_clear_error();
			} else {
			    if (flag_debug == 1)
				debug("%.200s %.200s %.200s %.200s", arg_ra[0], arg_ra[1],
				      arg_ra[2], arg_ra[3]);
			}
		    }
		    maxstringlen -= strlen(stringptr);
		    stringptr += strlen(stringptr);
		    snprintf(stringptr, maxstringlen, ";");
		    maxstringlen -= strlen(stringptr);
		    stringptr += strlen(stringptr);
		} else {
		    debug("ignored unaccepted stream %.16s(%.16s) from %.20s", type2str(ps.type),
			  ((ps.args == NULL) ? "0" : ps.args), source->addr);
		}
	    }
	    /*
	     * packet = parsed and in ascii in shared region -> copy to
	     * clients
	     */
	    snprintf(stringptr, maxstringlen, "\n");
	    stringptr += strlen(stringptr);
	    shared_setlen((stringptr - stringbuf));
	    debug("churnbuffer used: %d", (stringptr - stringbuf));
	    master_permitread();
	}			/* flag_hup == 0 */
    }				/* forever */

    /* NOT REACHED */
    return (EX_SOFTWARE);
}