/*
 * Copyright (C) 2009 Luigi Rizzo, Marta Carbone, Universita` di Pisa
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. 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 AUTHOR 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 AUTHOR 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.
 */

/*
 * $Id: glue.c 4469 2009-12-11 20:23:11Z marta $
 *
 * Userland functions missing in linux
 */

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

#ifndef HAVE_NAT
/* dummy nat functions */
void
ipfw_show_nat(int ac, char **av)
{
	fprintf(stderr, "%s unsupported\n", __FUNCTION__);
}

void
ipfw_config_nat(int ac, char **av)
{
	fprintf(stderr, "%s unsupported\n", __FUNCTION__);
}
#endif

#ifdef __linux__
int optreset;	/* missing in linux */
#endif

#if defined( __linux__ ) || defined(_WIN32)
/*
 * not implemented in linux.
 * taken from /usr/src/lib/libc/string/strlcpy.c
 */
size_t
strlcpy(char *dst, const char *src, size_t siz)
{
        char *d = dst;
        const char *s = src;
        size_t n = siz;
 
        /* Copy as many bytes as will fit */
        if (n != 0 && --n != 0) {
                do {
                        if ((*d++ = *s++) == 0)
                                break;
                } while (--n != 0);
        }

        /* Not enough room in dst, add NUL and traverse rest of src */
        if (n == 0) {
                if (siz != 0)
                        *d = '\0';              /* NUL-terminate dst */
                while (*s++)
                        ;
        }

        return(s - src - 1);    /* count does not include NUL */
}


/* missing in linux and windows */
long long int
strtonum(const char *nptr, long long minval, long long maxval,
         const char **errstr)
{
	return strtoll(nptr, (char **)errstr, 0);
}

/*
 * set or get system information
 * XXX lock acquisition/serialize calls 
 *
 * we export this as sys/module/ipfw_mod/parameters/___ 
 * This function get or/and set the value of the sysctl passed by
 * the name parameter. If the old value is not desired,
 * oldp and oldlenp should be set to NULL.
 *
 * XXX
 * I do not know how this works in FreeBSD in the case
 * where there are no write permission on the sysctl var.
 * We read the value and set return variables in any way
 * but returns -1 on write failures, regardless the
 * read success.
 * 
 * Since there is no information on types, in the following
 * code we assume a lenght of 4 is a int.
 * 
 * Returns 0 on success, -1 on errors.
 */
int
sysctlbyname(const char *name, void *oldp, size_t *oldlenp, void *newp,
         size_t newlen)
{
	FILE *fp;
	char *basename = "/sys/module/ipfw_mod/parameters/";
	char filename[256];	/* full filename */
	char *varp;
	int ret = 0;		/* return value */
	int d;

	/* debug message */
	if (0) fprintf(stderr, "%s name %s oldp %p oldlenp %p %d newp %p newlen %d\n", __FUNCTION__, name, \
		oldp, oldlenp, oldlenp ? *oldlenp : -1 , newp, (int) newlen);

	if (name == NULL) /* XXX set errno */
		return -1;

	/* locate the filename */
	varp = strrchr(name, '.');
	if (varp == NULL) /* XXX set errno */
		return -1;

	snprintf(filename, sizeof(filename), "%s%s", basename, varp+1);

	/*
	 * XXX we could open the file here, in rw mode
	 * but need to check if a file have write
	 * permissions.
	 */

	/* check parameters */
	if (oldp && oldlenp) { /* read mode */
		fp = fopen(filename, "r");
		if (fp == NULL) {
			fprintf(stderr, "%s fopen error reading filename %s\n", __FUNCTION__, filename);
			return -1;
		}
		if (*oldlenp == 4) {
			if (fscanf(fp, "%d", &d) == 1)
				memcpy(oldp, &d, *oldlenp);
			else
				ret = -1;
		}
		fclose(fp);
	}

	if (newp && newlen) { /* write */
		fp = fopen(filename, "w");
		if (fp == NULL) {
			fprintf(stderr, "%s fopen error writing filename %s\n", __FUNCTION__, filename);
			return -1;
		}
		if (newlen == 4) {
			if (fprintf(fp, "%d", *(int*)newp) < 1)
				ret = -1;
		}
			
		fclose(fp);
	}

	return ret;
}
#endif /* __linux__ || _WIN32 */