libmail/common/getdomain.c

/*
 * 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   */

#pragma ident   "%Z%%M% %I% %E% SMI"

#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);
}