readconfig.c

This project provides a proxy that allows telnet/tcp connections to be made to serial ports on a mac

/*
 *  ser2net - A program for allowing telnet connection to serial ports
 *  Copyright (C) 2001  Corey Minyard <[e-mail]>
 *
 *  This program 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 2 of the License, or
 *  (at your option) any later version.
 *
 *  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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

/* This file holds the code that reads the configuration file and
   calls the code in dataxfer to actually create all the ports in the
   configuration file. */

#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <syslog.h>

#include "dataxfer.h"
#include "readconfig.h"

#define MAX_LINE_SIZE 256	/* Maximum line length in the config file. */

#define MAX_BANNER_SIZE 256

static int config_num = 0;

struct banner_s
{
    char *name;
    char *str;
    struct banner_s *next;
};

/* All the banners in the system. */
struct banner_s *banners = NULL;

/* Parse the incoming banner, it may be on multiple lines. */
static void
handle_banner(char *name, char **strtok_data, FILE *instream, int *lineno)
{
    char banner[MAX_BANNER_SIZE+1];
    int len = 0;
    char *line = strtok_r(NULL, "\n", strtok_data);
    int line_len = strlen(line);
    char inbuf[MAX_LINE_SIZE];
    int truncated = 0;
    struct banner_s *new_banner;

    if (line_len >= MAX_BANNER_SIZE) {
	truncated = 1;
	line_len = MAX_BANNER_SIZE;
	memcpy(banner, line, MAX_BANNER_SIZE);
	len = MAX_BANNER_SIZE;
    } else {
	memcpy(banner, line, line_len);
	len = line_len;
    }
    while ((line_len > 0) && (line[line_len-1] == '\\')) {
	len--; /* Remove the '\' from the previous line. */
	(*lineno)++;
	if (fgets(inbuf, MAX_LINE_SIZE, instream) == NULL) {
	    syslog(LOG_ERR, "end of file in banner on %d", *lineno);
	    return;
	}
	line = strtok_r(inbuf, "\n", strtok_data);
	line_len = strlen(line);
	if (line_len+len >= MAX_BANNER_SIZE) {
	    truncated = 1;
	    memcpy(banner+len, line, MAX_BANNER_SIZE - len);
	} else {
	    memcpy(banner+len, line, line_len);
	    len += line_len;
	}
    }
    banner[len] = '\0';

    if (truncated)
	syslog(LOG_ERR, "banner ending on line %d was truncated, max length"
	       " is %d characters", *lineno, MAX_BANNER_SIZE);

    new_banner = malloc(sizeof(*new_banner));
    if (!new_banner) {
	syslog(LOG_ERR, "Out of memory handling banner on %d", *lineno);
	return;
    }

    new_banner->name = strdup(name);
    if (!new_banner->name) {
	syslog(LOG_ERR, "Out of memory handling banner on %d", *lineno);
	free(new_banner);
	return;
    }
    new_banner->str = strdup(banner);
    if (!new_banner->str) {
	syslog(LOG_ERR, "Out of memory handling banner on %d", *lineno);
	free(new_banner->name);
	free(new_banner);
	return;
    }

    new_banner->next = banners;
    banners = new_banner;
}

char *
find_banner(char *name)
{
    struct banner_s *banner = banners;

    while (banner) {
	if (strcmp(name, banner->name) == 0)
	    return banner->str;
	banner = banner->next;
    }
    return NULL;
}

static void
free_banners(void)
{
    struct banner_s *banner;

    while (banners) {
	banner = banners;
	banners = banners->next;
	free(banner->name);
	free(banner->str);
	free(banner);
    }
}

/* Read the specified configuration file and call the routine to
   create the ports. */
int
readconfig(char *filename)
{
    FILE *instream;
    char inbuf[MAX_LINE_SIZE];
    int  lineno = 0;
    int  rv = 0;

    instream = fopen(filename, "r");
    if (instream == NULL) {
	syslog(LOG_ERR, "Unable to open config file '%s': %m", filename);
	return -1;
    }

    free_banners();

    config_num++;

    while (fgets(inbuf, MAX_LINE_SIZE, instream) != NULL) {
	int len = strlen(inbuf);
	char *portnum, *state, *timeout, *devname, *devcfg;
	char *strtok_data;
	char *errstr;

	lineno++;
	if (inbuf[len-1] != '\n') {
	    syslog(LOG_ERR, "line %d is too long in config file", lineno);
	    continue;
	}

	if (inbuf[0] == '#') {
	    /* Ignore comments. */
	    continue;
	}

	inbuf[len-1] = '\0';
	portnum = strtok_r(inbuf, ":", &strtok_data);
	if (portnum == NULL) {
	    /* An empty line is ok. */
	    continue;
	}
	if (strcmp(portnum, "BANNER") == 0) {
	    char *name = strtok_r(NULL, ":", &strtok_data);
	    if (name == NULL) {
		syslog(LOG_ERR, "No banner name given on line %d", lineno);
		continue;
	    }
	    handle_banner(name, &strtok_data, instream, &lineno);
	    continue;
	}

	state = strtok_r(NULL, ":", &strtok_data);
	if (state == NULL) {
	    syslog(LOG_ERR, "No state given on line %d", lineno);
	    continue;
	}

	timeout = strtok_r(NULL, ":", &strtok_data);
	if (timeout == NULL) {
	    syslog(LOG_ERR, "No timeout given on line %d", lineno);
	    continue;
	}

	devname = strtok_r(NULL, ":", &strtok_data);
	if (devname == NULL) {
	    syslog(LOG_ERR, "No device name given on line %d", lineno);
	    continue;
	}

	devcfg = strtok_r(NULL, ":", &strtok_data);
	if (devcfg == NULL) {
	    /* An empty device config is ok. */
	    devcfg = "";
	}

	errstr = portconfig(portnum, state, timeout, devname, devcfg,
			    config_num);
	if (errstr != NULL) {
	    syslog(LOG_ERR, "Error on line %d, %s", lineno, errstr);
	}
    }

    /* Delete anything that wasn't in the new config file. */
    clear_old_port_config(config_num);

    fclose(instream);
    return rv;
}