/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
/*        All Rights Reserved   */

#include "libmail.h"
#include <sys/types.h>
#include <ctype.h>
#ifdef SVR4
#include <sys/utsname.h>
#include <sys/systeminfo.h>
#endif

#define NMLN 512
#ifdef SVR4
#if SYS_NMLN > NMLN
#undef NMLN
#define NMLN SYS_NMLN
#endif
#endif

static char *look4domain(char *, char *, int);
static char *readdomain(char *, int);

/*
 *  NAME
 *      maildomain() - retrieve the domain name
 *
 *  SYNOPSIS
 *      char *maildomain()
 *
 *  DESCRIPTION
 *      Retrieve the domain name from xgetenv("DOMAIN").
 *      If that is not set, look in /etc/resolv.conf, /etc/inet/named.boot
 *      and /etc/named.boot for "^domain[ ]+<domain>".
 *      If that is not set, use sysinfo(SI_SRPC_DOMAIN) from
 *      -lnsl. Otherwise, return an empty string.
 */

/* read a file for the domain */
static char *look4domain(char *file, char *buf, int size)
{
        char *ret = 0;
        FILE *fp = fopen(file, "r");

        if (!fp)
                return (0);

        while (fgets(buf, size, fp))
                if (strncmp(buf, "domain", 6) == 0)
        if (isspace(buf[6])) {
                char *x = skipspace(buf + 6);
                if (isgraph(*x)) {
                        trimnl(x);
                        strmove(buf, x);
                        ret = buf;
                        break;
                }
        }

        (void) fclose(fp);
        return (ret);
}

/* read the domain from the xenvironment or one of the files */
static char *readdomain(char *buf, int size)
{
        char *ret;

        if ((ret = xgetenv("DOMAIN")) != 0) {
                (void) strncpy(buf, ret, size);
                return (buf);
        }

        if (((ret = look4domain("/etc/resolv.conf", buf, size)) != 0) ||
            ((ret = look4domain("/etc/inet/named.boot", buf, size)) != 0) ||
            ((ret = look4domain("/etc/named.boot", buf, size)) != 0))
                return (ret);

#ifdef SVR4
        if (sysinfo(SI_SRPC_DOMAIN, buf, size) >= 0)
                return (buf);
#endif

        return (0);
}

char *
maildomain(void)
{
        static char *domain = 0;
        static char dombuf[NMLN+1] = ".";

        /* if we've already been here, return the info */
        if (domain != 0)
                return (domain);

        domain = readdomain(dombuf+1, NMLN);

        /* Make certain that the domain begins with a single dot */
        /* and does not have one at the end. */
        if (domain) {
                size_t len;
                domain = dombuf;
                while (*domain && *domain == '.')
                        domain++;
                domain--;
                len = strlen(domain);
                while ((len > 0) && (domain[len-1] == '.'))
                        domain[--len] = '\0';
        }
        /* no domain information */
        else
                domain = "";

        return (domain);
}