bin/dig/nslookup.c

	nslookup.c revision cc48bb397fa6ba889f25157840492e68114dec8f
/*
 * Copyright (C) 2000  Internet Software Consortium.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND INTERNET SOFTWARE CONSORTIUM
 * DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL
 * INTERNET SOFTWARE CONSORTIUM BE LIABLE FOR ANY SPECIAL, DIRECT,
 * INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
 * FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
 * NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
 * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

/* $Id: nslookup.c,v 1.37 2000/09/01 21:54:23 bwelling Exp $ */

#include <config.h>

#include <stdlib.h>

extern int h_errno;

#include <isc/app.h>
#include <isc/buffer.h>
#include <isc/commandline.h>
#include <isc/condition.h>
#include <isc/mutex.h>
#include <isc/string.h>
#include <isc/timer.h>
#include <isc/util.h>
#include <isc/task.h>

#include <dns/message.h>
#include <dns/name.h>
#include <dns/rdata.h>
#include <dns/rdataclass.h>
#include <dns/rdataset.h>
#include <dns/rdatatype.h>

#include <dig/dig.h>

extern ISC_LIST(dig_lookup_t) lookup_list;
extern ISC_LIST(dig_server_t) server_list;
extern ISC_LIST(dig_searchlist_t) search_list;

extern isc_boolean_t have_ipv6, show_details,
    usesearch, trace, qr, debugging;
extern in_port_t port;
extern unsigned int timeout;
extern isc_mem_t *mctx;
extern dns_messageid_t id;
extern char *rootspace[BUFSIZE];
extern isc_buffer_t rootbuf;
extern int sendcount;
extern int ndots;
extern int tries;
extern int lookup_counter;
extern char fixeddomain[MXNAME];
extern int exitcode;
extern isc_taskmgr_t *taskmgr;
extern char *progname;

isc_boolean_t short_form = ISC_TRUE, printcmd = ISC_TRUE,
    filter = ISC_FALSE, showallsoa = ISC_FALSE,
    tcpmode = ISC_FALSE, deprecation_msg = ISC_TRUE;

isc_uint16_t bufsize = 0;
isc_boolean_t identify = ISC_FALSE,
    trace = ISC_FALSE, ns_search_only = ISC_FALSE,
    forcecomment = ISC_FALSE, stats = ISC_TRUE,
    comments = ISC_TRUE, section_question = ISC_TRUE,
    section_answer = ISC_TRUE, section_authority = ISC_TRUE,
    section_additional = ISC_TRUE, recurse = ISC_TRUE,
    defname = ISC_TRUE, aaonly = ISC_FALSE;
isc_mutex_t lock;
isc_condition_t cond;
isc_boolean_t busy = ISC_FALSE, in_use = ISC_FALSE;
char defclass[MXRD] = "IN";
char deftype[MXRD] = "A";

static const char *rcodetext[] = {
    "NOERROR",
    "FORMERR",
    "SERVFAIL",
    "NXDOMAIN",
    "NOTIMPL",
    "REFUSED",
    "YXDOMAIN",
    "YXRRSET",
    "NXRRSET",
    "NOTAUTH",
    "NOTZONE",
    "RESERVED11",
    "RESERVED12",
    "RESERVED13",
    "RESERVED14",
    "RESERVED15",
    "BADVERS"
};

static const char *rtypetext[] = {
    "rtype_0 = ",           /* 0 */
    "internet address = ",      /* 1 */
    "nameserver = ",        /* 2 */
    "md = ",            /* 3 */
    "mf = ",            /* 4 */
    "canonical name = ",        /* 5 */
    "soa = ",               /* 6 */
    "mb = ",                /* 7 */
    "mg = ",                /* 8 */
    "mr = ",                /* 9 */
    "rtype_10 = ",              /* 10 */
    "protocol = ",          /* 11 */
    "name = ",          /* 12 */
    "hinfo = ",         /* 13 */
    "minfo = ",         /* 14 */
    "mail exchanger = ",            /* 15 */
    "text = ",          /* 16 */
    "rp = ",                /* 17 */
    "afsdb = ",         /* 18 */
    "x25 address = ",       /* 19 */
    "isdn address = ",      /* 20 */
    "rt = ",            /* 21 */
    "nsap = ",          /* 22 */
    "nsap_ptr = ",          /* 23 */
    "signature = ",         /* 24 */
    "key = ",           /* 25 */
    "px = ",                /* 26 */
    "gpos = ",              /* 27 */
    "has AAAA address",         /* 28 */
    "loc = ",               /* 29 */
    "next = ",          /* 30 */
    "rtype_31 = ",          /* 31 */
    "rtype_32 = ",          /* 32 */
    "service = ",               /* 33 */
    "rtype_34 = ",          /* 34 */
    "naptr = ",         /* 35 */
    "kx = ",            /* 36 */
    "cert = ",          /* 37 */
    "v6 address = ",        /* 38 */
    "dname = ",         /* 39 */
    "rtype_40 = ",              /* 40 */
    "optional = "};         /* 41 */


static void
show_usage(void) {
    fputs("Usage:\n", stderr);
}

void
dighost_shutdown(void) {
    debug("dighost_shutdown()");
    isc_mutex_lock(&lock);
    busy = ISC_FALSE;
    debug("signalling out");
    isc_condition_signal(&cond);
    isc_mutex_unlock(&lock);
}

void
received(int bytes, int frmsize, char *frm, dig_query_t *query) {
    UNUSED(bytes);
    UNUSED(frmsize);
    UNUSED(frm);
    UNUSED(query);
}

void
trying(int frmsize, char *frm, dig_lookup_t *lookup) {
    UNUSED(frmsize);
    UNUSED(frm);
    UNUSED(lookup);

}

static isc_result_t
printsection(dig_query_t *query, dns_message_t *msg, isc_boolean_t headers,
         dns_section_t section) {
    isc_result_t result, loopresult;
    isc_buffer_t *b = NULL;
    dns_name_t *name;
    dns_rdataset_t *rdataset = NULL;
    dns_rdata_t rdata;
    char *ptr;

    UNUSED(query);
    UNUSED(headers);

    debug("printsection()");

    result = dns_message_firstname(msg, section);
    if (result == ISC_R_NOMORE)
        return (ISC_R_SUCCESS);
    else if (result != ISC_R_SUCCESS)
        return (result);
    result = isc_buffer_allocate(mctx, &b, MXNAME);
    check_result(result, "isc_buffer_allocate");
    for (;;) {
        name = NULL;
        dns_message_currentname(msg, section,
                    &name);
        for (rdataset = ISC_LIST_HEAD(name->list);
             rdataset != NULL;
             rdataset = ISC_LIST_NEXT(rdataset, link)) {
            loopresult = dns_rdataset_first(rdataset);
            while (loopresult == ISC_R_SUCCESS) {
                dns_rdataset_current(rdataset, &rdata);
                switch (rdata.type) {
                case dns_rdatatype_a:
                    if (section != DNS_SECTION_ANSWER)
                        goto def_short_section;
                    isc_buffer_clear(b);
                    result = dns_name_totext(name,
                            ISC_TRUE,
                            b);
                    check_result(result,
                             "dns_name_totext");
                    printf("Name:\t%.*s\n",
                           (int)isc_buffer_usedlength(b),
                           (char*)isc_buffer_base(b));
                    isc_buffer_clear(b);
                    result = dns_rdata_totext(&rdata,
                                  NULL,
                                  b);
                    check_result(result,
                             "dns_rdata_totext");
                    printf("Address: %.*s\n",
                           (int)isc_buffer_usedlength(b),
                           (char*)isc_buffer_base(b));
                    break;
                case dns_rdatatype_soa:
                    isc_buffer_clear(b);
                    result = dns_name_totext(name,
                            ISC_TRUE,
                            b);
                    check_result(result,
                             "dns_name_totext");
                    printf("%.*s\n",
                           (int)isc_buffer_usedlength(b),
                           (char*)isc_buffer_base(b));
                    isc_buffer_clear(b);
                    result = dns_rdata_totext(&rdata,
                                  NULL,
                                  b);
                    check_result(result,
                             "dns_rdata_totext");
                    ((char *)isc_buffer_used(b))[0]=0;
                    ptr = strtok(isc_buffer_base(b),
                             " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\torigin = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\tmail addr = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\tserial = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\trefresh = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\tretry = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\texpire = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\tminimum = %s\n",
                           ptr);
                    break;
                default:
                def_short_section:
                    isc_buffer_clear(b);
                    result = dns_name_totext(name,
                            ISC_TRUE,
                            b);
                    check_result(result,
                             "dns_name_totext");
                    if (rdata.type <= 41)
                        printf("%.*s\t%s",
                        (int)isc_buffer_usedlength(b),
                        (char*)isc_buffer_base(b),
                        rtypetext[rdata.type]);
                    else
                        printf("%.*s\trdata_%d = ",
                        (int)isc_buffer_usedlength(b),
                        (char*)isc_buffer_base(b),
                         rdata.type);
                    isc_buffer_clear(b);
                    result = dns_rdata_totext(&rdata,
                                  NULL, b);
                    check_result(result,
                             "dns_rdata_totext");
                    printf("%.*s\n",
                           (int)isc_buffer_usedlength(b),
                           (char*)isc_buffer_base(b));
                }
                loopresult = dns_rdataset_next(rdataset);
            }
        }
        result = dns_message_nextname(msg, section);
        if (result == ISC_R_NOMORE)
            break;
        else if (result != ISC_R_SUCCESS) {
            isc_buffer_free (&b);
            return (result);
        }
    }
    isc_buffer_free(&b);
    return (ISC_R_SUCCESS);
}

static isc_result_t
detailsection(dig_query_t *query, dns_message_t *msg, isc_boolean_t headers,
         dns_section_t section) {
    isc_result_t result, loopresult;
    isc_buffer_t *b = NULL;
    dns_name_t *name;
    dns_rdataset_t *rdataset = NULL;
    dns_rdata_t rdata;
    char *ptr;

    UNUSED(query);

    debug("detailsection()");

    if (headers) {
        switch (section) {
        case DNS_SECTION_QUESTION:
            puts("    QUESTIONS:");
            break;
        case DNS_SECTION_ANSWER:
            puts("    ANSWERS:");
            break;
        case DNS_SECTION_AUTHORITY:
            puts("    AUTHORITY RECORDS:");
            break;
        case DNS_SECTION_ADDITIONAL:
            puts("    ADDITIONAL RECORDS:");
            break;
        }
    }

    result = dns_message_firstname(msg, section);
    if (result == ISC_R_NOMORE)
        return (ISC_R_SUCCESS);
    else if (result != ISC_R_SUCCESS)
        return (result);
    result = isc_buffer_allocate(mctx, &b, MXNAME);
    check_result(result, "isc_buffer_allocate");
    for (;;) {
        name = NULL;
        dns_message_currentname(msg, section,
                    &name);
        for (rdataset = ISC_LIST_HEAD(name->list);
             rdataset != NULL;
             rdataset = ISC_LIST_NEXT(rdataset, link)) {
            loopresult = dns_rdataset_first(rdataset);
            while (loopresult == ISC_R_SUCCESS) {
                dns_rdataset_current(rdataset, &rdata);
                isc_buffer_clear(b);
                result = dns_name_totext(name,
                             ISC_TRUE,
                             b);
                check_result(result,
                         "dns_name_totext");
                printf("    ->  %.*s\n",
                       (int)isc_buffer_usedlength(b),
                       (char*)isc_buffer_base(b));
                switch (rdata.type) {
                case dns_rdatatype_soa:
                    isc_buffer_clear(b);
                    result = dns_rdata_totext(&rdata,
                                  NULL,
                                  b);
                    check_result(result,
                             "dns_rdata_totext");
                    ((char *)isc_buffer_used(b))[0]=0;
                    ptr = strtok(isc_buffer_base(b),
                             " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\torigin = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\tmail addr = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\tserial = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\trefresh = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\tretry = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\texpire = %s\n",
                           ptr);
                    ptr = strtok(NULL, " \t\r\n");
                    if (ptr == NULL)
                        break;
                    printf("\tminimum = %s\n",
                           ptr);
                    break;
                default:
                    isc_buffer_clear(b);
                    if (rdata.type <= 41)
                        printf("\t%s",
                        rtypetext[rdata.type]);
                    else
                        printf("\trdata_%d = ",
                         rdata.type);
                    isc_buffer_clear(b);
                    result = dns_rdata_totext(&rdata,
                                  NULL, b);
                    check_result(result,
                             "dns_rdata_totext");
                    printf("%.*s\n",
                           (int)isc_buffer_usedlength(b),
                           (char*)isc_buffer_base(b));
                }
                loopresult = dns_rdataset_next(rdataset);
            }
        }
        result = dns_message_nextname(msg, section);
        if (result == ISC_R_NOMORE)
            break;
        else if (result != ISC_R_SUCCESS) {
            isc_buffer_free (&b);
            return (result);
        }
    }
    isc_buffer_free(&b);
    return (ISC_R_SUCCESS);
}

isc_result_t
printmessage(dig_query_t *query, dns_message_t *msg, isc_boolean_t headers) {
    isc_buffer_t *b = NULL;
    isc_region_t r;
    isc_result_t result;

    debug("printmessage()");

    if (msg->rcode != 0) {
        result = isc_buffer_allocate(mctx, &b, MXNAME);
        check_result(result, "isc_buffer_allocate");
        result = dns_name_totext(query->lookup->name, ISC_FALSE,
                     b);
        check_result(result, "dns_name_totext");
        isc_buffer_usedregion(b, &r);
        printf("** server can't find %.*s: %s\n",
               (int)r.length, (char*)r.base,
               rcodetext[msg->rcode]);
        isc_buffer_free(&b);
        debug("returning with rcode == 0");
        return (ISC_R_SUCCESS);
    }
    debug("continuing on with rcode != 0");
    result = isc_buffer_allocate(mctx, &b, MXNAME);
    check_result(result, "isc_buffer_allocate");
    printf("Server:\t\t%s\n", query->servname);
    result = isc_sockaddr_totext(&query->sockaddr, b);
    check_result(result, "isc_sockaddr_totext");
    printf("Address:\t%.*s\n", (int)isc_buffer_usedlength(b),
           (char*)isc_buffer_base(b));
    isc_buffer_free(&b);
    puts("");
    if (!short_form){
        puts("------------");
        /*      detailheader(query, msg);*/
        detailsection(query, msg, headers, DNS_SECTION_QUESTION);
        detailsection(query, msg, headers, DNS_SECTION_ANSWER);
        detailsection(query, msg, headers, DNS_SECTION_AUTHORITY);
        detailsection(query, msg, headers, DNS_SECTION_ADDITIONAL);
        puts("------------");
    }

    if ((msg->flags & DNS_MESSAGEFLAG_AA) == 0)
        puts("Non-authorative answer:");
    printsection(query, msg, headers, DNS_SECTION_ANSWER);

    if (((msg->flags & DNS_MESSAGEFLAG_AA) == 0) &&
        (query->lookup->rdtype != dns_rdatatype_a)) {
        puts("\nAuthorative answers can be found from:");
        printsection(query, msg, headers,
                 DNS_SECTION_AUTHORITY);
        printsection(query, msg, headers,
                 DNS_SECTION_ADDITIONAL);
    }
    return (ISC_R_SUCCESS);
}

static void
show_settings(isc_boolean_t full) {
    dig_server_t *srv;
    isc_sockaddr_t sockaddr;
    isc_buffer_t *b = NULL;
    isc_result_t result;

    srv = ISC_LIST_HEAD(server_list);

    while (srv != NULL) {
        result = isc_buffer_allocate(mctx, &b, MXNAME);
        check_result(result, "isc_buffer_allocate");
        get_address(srv->servername, 53, &sockaddr);
        result = isc_sockaddr_totext(&sockaddr, b);
        check_result(result, "isc_sockaddr_totext");
        printf("Default server: %s\nAddress: %.*s\n",
            srv->servername, (int)isc_buffer_usedlength(b),
            (char*)isc_buffer_base(b));
        isc_buffer_free(&b);
        if (!full)
            return;
        srv = ISC_LIST_NEXT(srv, link);
    }
    printf("\n\tSet options:\n");
    printf("\t  %s\t\t\t%s\t\t%s\n",
        tcpmode?"vc":"novc", short_form?"nodebug":"debug",
        debugging?"d2":"nod2");
    printf("\t  %s\t\t%s\t%s\n",
        defname?"defname":"nodefname",
        usesearch?"search  ":"nosearch",
        recurse?"recurse":"norecurse");
    printf("\t  timeout = %d\t\tretry = %d\tport = %d\n",
        timeout, tries, port);
    printf("\t  querytype = %-8s\tclass = %s\n",deftype, defclass);
#if 0
    printf("\t  domain = %s\n", fixeddomain);
#endif

}

static isc_boolean_t
testtype(char *typetext) {
    isc_result_t result;
    isc_textregion_t tr;
    dns_rdatatype_t rdtype;

    tr.base = typetext;
    tr.length = strlen(typetext);
    result = dns_rdatatype_fromtext(&rdtype, &tr);
    return (ISC_TF(result == ISC_R_SUCCESS));
}

static isc_boolean_t
testclass(char *typetext) {
    isc_result_t result;
    isc_textregion_t tr;
    dns_rdataclass_t rdclass;

    tr.base = typetext;
    tr.length = strlen(typetext);
    result = dns_rdataclass_fromtext(&rdclass, &tr);
    return (ISC_TF(result == ISC_R_SUCCESS));
}


static void
setoption(char *opt) {
    dig_server_t *srv;

    if (strncasecmp(opt,"all",4) == 0) {
        show_settings(ISC_TRUE);
    } else if (strncasecmp(opt, "class=", 6) == 0) {
        strncpy(defclass, &opt[6], MXRD);
    } else if (strncasecmp(opt, "cl=", 3) == 0) {
        strncpy(defclass, &opt[3], MXRD);
    } else if (strncasecmp(opt, "type=", 5) == 0) {
        if (testtype(&opt[5]))
            strncpy(deftype, &opt[5], MXRD);
    } else if (strncasecmp(opt, "ty=", 3) == 0) {
        if (testclass(&opt[3]))
            strncpy(defclass, &opt[3], MXRD);
    } else if (strncasecmp(opt, "querytype=", 10) == 0) {
        strncpy(deftype, &opt[10], MXRD);
    } else if (strncasecmp(opt, "query=", 6) == 0) {
        strncpy(deftype, &opt[6], MXRD);
    } else if (strncasecmp(opt, "qu=", 3) == 0) {
        strncpy(deftype, &opt[3], MXRD);
#if 0
        /* XXXMWS domain= doesn't work now. */
    } else if (strncasecmp(opt, "domain=", 7) == 0) {
        strncpy(fixeddomain, &opt[7], MXNAME);
    } else if (strncasecmp(opt, "do=", 3) == 0) {
        strncpy(fixeddomain, &opt[3], MXNAME);
#endif
    } else if (strncasecmp(opt, "port=", 5) == 0) {
        port = atoi(&opt[5]);
    } else if (strncasecmp(opt, "po=", 3) == 0) {
        port = atoi(&opt[3]);
    } else if (strncasecmp(opt, "timeout=", 8) == 0) {
        timeout = atoi(&opt[8]);
    } else if (strncasecmp(opt, "t=", 2) == 0) {
        timeout = atoi(&opt[2]);
    } else if (strncasecmp(opt, "retry=", 6) == 0) {
        tries = atoi(&opt[6]);
    } else if (strncasecmp(opt, "ret=", 4) == 0) {
        tries = atoi(&opt[4]);
    } else if (strncasecmp(opt, "def", 3) == 0) {
        defname = ISC_TRUE;
    } else if (strncasecmp(opt, "nodef", 5) == 0) {
        defname = ISC_FALSE;
    } else if (strncasecmp(opt, "deb", 3) == 0) {
        short_form = ISC_FALSE;
    } else if (strncasecmp(opt, "nodeb", 5) == 0) {
        short_form = ISC_TRUE;
    } else if (strncasecmp(opt, "d2", 2) == 0) {
        debugging = ISC_TRUE;
    } else if (strncasecmp(opt, "nod2", 4) == 0) {
        debugging = ISC_FALSE;
    } else if (strncasecmp(opt, "sil",3) == 0) {
        deprecation_msg = ISC_FALSE;
    } else {
        srv = make_server(opt);
        debug("server is %s", srv->servername);
        ISC_LIST_APPEND(server_list, srv, link);
    }
}

static dig_lookup_t*
addlookup(char *opt) {
    dig_lookup_t *lookup;
    isc_result_t result;
    isc_textregion_t tr;
    dns_rdatatype_t rdtype;
    dns_rdataclass_t rdclass;

    debug("addlookup()");
    tr.base = deftype;
    tr.length = strlen(deftype);
    result = dns_rdatatype_fromtext(&rdtype, &tr);
    INSIST(result == ISC_R_SUCCESS);
    tr.base = defclass;
    tr.length = strlen(defclass);
    result = dns_rdataclass_fromtext(&rdclass, &tr);
    INSIST(result == ISC_R_SUCCESS);
    lookup = make_empty_lookup();
    strncpy(lookup->textname, opt, MXNAME-1);
    lookup->rdtype = rdtype;
    lookup->rdclass = rdclass;
    lookup->trace = ISC_TF(trace || ns_search_only);
    lookup->trace_root = trace;
    lookup->ns_search_only = ns_search_only;
    lookup->identify = identify;
    lookup->recurse = recurse;
    lookup->aaonly = aaonly;
    lookup->retries = tries;
    lookup->udpsize = bufsize;
    lookup->comments = comments;
    lookup->tcp_mode = tcpmode;
    lookup->stats = stats;
    lookup->section_question = section_question;
    lookup->section_answer = section_answer;
    lookup->section_authority = section_authority;
    lookup->section_additional = section_additional;
    lookup->new_search = ISC_TRUE;
    ISC_LIST_INIT(lookup->q);
    ISC_LIST_APPEND(lookup_list, lookup, link);
    lookup->origin = NULL;
    ISC_LIST_INIT(lookup->my_server_list);
    debug("looking up %s", lookup->textname);
    return (lookup);
}

static void
flush_server_list(void) {
    dig_server_t *s, *ps;

    debug("flush_lookup_list()");
    s = ISC_LIST_HEAD(server_list);
    while (s != NULL) {
        ps = s;
        s = ISC_LIST_NEXT(s, link);
        ISC_LIST_DEQUEUE(server_list, ps, link);
        isc_mem_free(mctx, ps);
    }
}

/*
 * This works on the global server list, instead of on a per-lookup
 * server list, since the change is persistent.
 */
static void
setsrv(char *opt) {
    dig_server_t *srv;

    flush_server_list();
    srv=isc_mem_allocate(mctx, sizeof(struct dig_server));
    if (srv == NULL)
        fatal("Memory allocation failure.");
    strncpy(srv->servername, opt, MXNAME-1);
    ISC_LIST_APPEND(server_list, srv, link);
}

static void
get_next_command(void) {
    char input[COMMSIZE];
    char *ptr, *arg;

    fputs("> ", stderr);
    ptr = fgets(input, COMMSIZE, stdin);
    if (ptr == NULL) {
        in_use = ISC_FALSE;
        return;
    }
    ptr = strtok(input, " \t\r\n");
    if (ptr == NULL) {
        in_use = ISC_FALSE;
        return;
    }
    arg = strtok(NULL, " \t\r\n");
    if ((strcasecmp(ptr, "set") == 0) &&
        (arg != NULL))
        setoption(arg);
    else if ((strcasecmp(ptr, "server") == 0) ||
         (strcasecmp(ptr, "lserver") == 0)) {
        printf("Server:\t%s\n", arg);
        setsrv(arg);
    } else
        addlookup(ptr);
}

static void
parse_args(int argc, char **argv) {
    dig_lookup_t *lookup = NULL;
    isc_boolean_t have_lookup = ISC_FALSE;

    for (argc--, argv++; argc > 0; argc--, argv++) {
        debug("main parsing %s", argv[0]);
        if (argv[0][0] == '-') {
            if ((argv[0][1] == 'h') &&
                (argv[0][2] == 0)) {
                show_usage();
                exit (1);
            }
            if (argv[0][1] != 0)
                setoption(&argv[0][1]);
            else
                have_lookup = ISC_TRUE;
        } else {
            if (!have_lookup) {
                have_lookup = ISC_TRUE;
                in_use = ISC_TRUE;
                lookup = addlookup(argv[0]);
            }
            else
                setsrv(argv[0]);
        }
    }
}

static void
flush_lookup_list(void) {
    dig_lookup_t *l, *lp;
    dig_query_t *q, *qp;
    dig_server_t *s, *sp;

    lookup_counter = 0;
    l = ISC_LIST_HEAD(lookup_list);
    while (l != NULL) {
        q = ISC_LIST_HEAD(l->q);
        while (q != NULL) {
            if (q->sock != NULL) {
                isc_socket_cancel(q->sock, NULL,
                          ISC_SOCKCANCEL_ALL);
                isc_socket_detach(&q->sock);
            }
            if (ISC_LINK_LINKED(&q->recvbuf, link))
                ISC_LIST_DEQUEUE(q->recvlist, &q->recvbuf,
                         link);
            if (ISC_LINK_LINKED(&q->lengthbuf, link))
                ISC_LIST_DEQUEUE(q->lengthlist, &q->lengthbuf,
                         link);
            isc_buffer_invalidate(&q->recvbuf);
            isc_buffer_invalidate(&q->lengthbuf);
            qp = q;
            q = ISC_LIST_NEXT(q, link);
            ISC_LIST_DEQUEUE(l->q, qp, link);
            isc_mem_free(mctx, qp);
        }
        s = ISC_LIST_HEAD(l->my_server_list);
        while (s != NULL) {
            sp = s;
            s = ISC_LIST_NEXT(s, link);
            ISC_LIST_DEQUEUE(l->my_server_list, sp, link);
            isc_mem_free(mctx, sp);

        }
        if (l->sendmsg != NULL)
            dns_message_destroy(&l->sendmsg);
        if (l->timer != NULL)
            isc_timer_detach(&l->timer);
        lp = l;
        l = ISC_LIST_NEXT(l, link);
        ISC_LIST_DEQUEUE(lookup_list, lp, link);
        isc_mem_free(mctx, lp);
    }
}

int
main(int argc, char **argv) {
    isc_result_t result;

    ISC_LIST_INIT(lookup_list);
    ISC_LIST_INIT(server_list);
    ISC_LIST_INIT(search_list);

    setup_libs();
    progname = argv[0];
    result = isc_mutex_init(&lock);
    check_result(result, "isc_mutex_init");
    result = isc_condition_init(&cond);
    check_result(result, "isc_condition_init");
    result = isc_mutex_trylock(&lock);
    check_result(result, "isc_mutex_trylock");

    parse_args(argc, argv);

    if (deprecation_msg) {
        fputs(
"Note:  nslookup is deprecated and may be removed from future releases.\n"
"Consider using the `dig' or `host' programs instead.  Run nslookup with\n"
"the `-sil[ent]' option to prevent this message from appearing.\n", stderr);
    }
    setup_system();

    if (in_use) {
        busy = ISC_TRUE;
        start_lookup();
        while (busy) {
            result = isc_condition_wait(&cond, &lock);
            check_result(result, "isc_condition_wait");
        }
        flush_lookup_list();
        in_use = ISC_FALSE;
    } else {
        show_settings(ISC_FALSE);
        in_use = ISC_TRUE;
    }

    while (in_use) {
        get_next_command();
        if (ISC_LIST_HEAD(lookup_list) != NULL) {
            busy = ISC_TRUE;
            start_lookup();
            while (busy) {
                result = isc_condition_wait(&cond, &lock);
                check_result(result, "isc_condition_wait");
            }
            debug("out of the condition wait");
            flush_lookup_list();
        }
    }

    puts("");
    debug("done, and starting to shut down");
    destroy_libs();
    DESTROYLOCK(&lock);
    isc_condition_destroy(&cond);
    if (taskmgr != NULL) {
        debug("freeing taskmgr");
        isc_taskmgr_destroy(&taskmgr);
        }
    if (isc_mem_debugging != 0)
        isc_mem_stats(mctx, stderr);
    isc_app_finish();
    if (mctx != NULL)
        isc_mem_destroy(&mctx);

    return (0);
}