/*      $OpenBSD: ypserv_db.c,v 1.32 2021/10/09 18:43:51 deraadt Exp $ */

/*
 * Copyright (c) 1994 Mats O Jansson <moj@stacken.kth.se>
 * Copyright (c) 1996 Charles D. Cranor
 * All rights reserved.
 *
 * 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 ``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 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.
 */

/*
 * major revision/cleanup of Mats' version
 * done by Chuck Cranor <chuck@ccrc.wustl.edu>
 * Jan 1996.
 */

#include <rpc/rpc.h>
#include <rpcsvc/yp.h>
#include <rpcsvc/ypclnt.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <netdb.h>
#include <resolv.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/queue.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <syslog.h>
#include <errno.h>
#include "yplog.h"
#include "ypdb.h"
#include "ypdef.h"
#include "ypserv.h"

LIST_HEAD(domainlist, opt_domain);      /* LIST of domains */
LIST_HEAD(maplist, opt_map);            /* LIST of maps (in a domain) */
TAILQ_HEAD(mapq, opt_map);              /* TAILQ of maps (LRU) */

struct opt_map {
        mapname map;                    /* map name (malloc'd) */
        DBM     *db;                    /* database */
        struct opt_domain *dom;         /* back ptr to our domain */
        int     host_lookup;            /* host lookup */
        int     secure;                 /* secure map? */
        TAILQ_ENTRY(opt_map) mapsq;   /* map queue pointers */
        LIST_ENTRY(opt_map) mapsl;      /* map list pointers */
};

struct opt_domain {
        domainname      domain;         /* domain name (malloc'd) */
        struct maplist  dmaps;          /* the domain's active maps */
        LIST_ENTRY(opt_domain) domsl;   /* global linked list of domains */
};

struct domainlist doms;                 /* global list of domains */
struct mapq maps;                       /* global queue of maps (LRU) */

extern int usedns;

/*
 * ypdb_init: init the queues and lists
 */
void
ypdb_init(void)
{
        LIST_INIT(&doms);
        TAILQ_INIT(&maps);
}

/*
 * yp_private:
 * Check if key is a YP private key. Return TRUE if it is and
 * ypprivate is FALSE.
 */
static int
yp_private(datum key, int ypprivate)
{
        if (ypprivate)
                return (FALSE);

        if (key.dsize == 0 || key.dptr == NULL)
                return (FALSE);

        if (key.dsize == YP_LAST_LEN &&
            strncmp(key.dptr, YP_LAST_KEY, YP_LAST_LEN) == 0)
                return(TRUE);
        if (key.dsize == YP_INPUT_LEN &&
            strncmp(key.dptr, YP_INPUT_KEY, YP_INPUT_LEN) == 0)
                return(TRUE);
        if (key.dsize == YP_OUTPUT_LEN &&
            strncmp(key.dptr, YP_OUTPUT_KEY, YP_OUTPUT_LEN) == 0)
                return(TRUE);
        if (key.dsize == YP_MASTER_LEN &&
            strncmp(key.dptr, YP_MASTER_KEY, YP_MASTER_LEN) == 0)
                return(TRUE);
        if (key.dsize == YP_DOMAIN_LEN &&
            strncmp(key.dptr, YP_DOMAIN_KEY, YP_DOMAIN_LEN) == 0)
                return(TRUE);
        if (key.dsize == YP_INTERDOMAIN_LEN &&
            strncmp(key.dptr, YP_INTERDOMAIN_KEY, YP_INTERDOMAIN_LEN) == 0)
                return(TRUE);
        if (key.dsize == YP_SECURE_LEN &&
            strncmp(key.dptr, YP_SECURE_KEY, YP_SECURE_LEN) == 0)
                return(TRUE);
        return(FALSE);
}

/*
 * Close least recent used map. This routine is called when we have
 * no more file descripotors free, or we want to close all maps.
 */
static void
ypdb_close_last(void)
{
        struct opt_map *last;

        if (TAILQ_EMPTY(&maps)) {
                yplog("  ypdb_close_last: LRU list is empty!");
                return;
        }

        last = TAILQ_LAST(&maps, mapq);

        TAILQ_REMOVE(&maps, last, mapsq);       /* remove from LRU circleq */
        LIST_REMOVE(last, mapsl);               /* remove from domain list */

#ifdef DEBUG
        yplog("  ypdb_close_last: closing map %s in domain %s [db=0x%x]",
            last->map, last->dom->domain, last->db);
#endif

        ypdb_close(last->db);                   /* close DB */
        free(last->map);                        /* free map name */
        free(last);                             /* free map */
}

/*
 * Close all open maps.
 */
void
ypdb_close_all(void)
{

#ifdef DEBUG
        yplog("  ypdb_close_all(): start");
#endif
        while (!TAILQ_EMPTY(&maps))
                ypdb_close_last();
#ifdef DEBUG
        yplog("  ypdb_close_all(): done");
#endif
}

/*
 * Close Database if Open/Close Optimization isn't turned on.
 */
static void
ypdb_close_db(DBM *db)
{
#ifdef DEBUG
        yplog("  ypdb_close_db(0x%x)", db);
#endif
#ifndef OPTDB
        ypdb_close_all();
#endif
}

/*
 * ypdb_open_db
 */
DBM *
ypdb_open_db(domainname domain, mapname map, ypstat *status,
    struct opt_map **map_info)
{
        char map_path[PATH_MAX];
        static char   *domain_key = YP_INTERDOMAIN_KEY;
        static char   *secure_key = YP_SECURE_KEY;
        DBM     *db;
        struct opt_domain *d = NULL;
        struct opt_map  *m = NULL;
        datum   k, v;
#ifdef OPTDB
        int     i;
#endif

        /*
         * check for preloaded domain, map
         */
        LIST_FOREACH(d, &doms, domsl) {
                if (strcmp(domain, d->domain) == 0)
                        break;
        }

        if (d) {
                LIST_FOREACH(m, &d->dmaps, mapsl)
                        if (strcmp(map, m->map) == 0)
                                break;
        }

        /*
         * map found open?
         */
        if (m) {
#ifdef DEBUG
                yplog("  ypdb_open_db: cached open: domain=%s, map=%s, db=0x%x",
                    domain, map, m->db);
#endif
                TAILQ_REMOVE(&maps, m, mapsq);  /* adjust LRU queue */
                TAILQ_INSERT_HEAD(&maps, m, mapsq);
                *status = YP_TRUE;
                if (map_info)
                        *map_info = m;
                return(m->db);
        }

        /* Check for illegal charcaters */

        if (strchr(domain, '/')) {
                *status = YP_NODOM;
                return (NULL);
        }
        if (strchr(map, '/')) {
                *status = YP_NOMAP;
                return (NULL);
        }

        /*
         * open map
         */
#ifdef OPTDB
        i = 0;
        while (i == 0) {
#endif
                snprintf(map_path, sizeof(map_path), "%s/%s/%s", YP_DB_PATH,
                    domain, map);
                db = ypdb_open(map_path, O_RDONLY, 0444);
#ifdef OPTDB
                if (db == NULL) {
#ifdef DEBUG
                        yplog("  ypdb_open_db: errno %d (%s)",
                            errno, sys_errlist[errno]);
#endif
                        if (errno == ENFILE || errno == EMFILE) {
                                ypdb_close_last();
                        } else {
                                i = errno;
                        }
                } else {
                        i = 4711;
                }
        }
#endif
        *status = YP_NOMAP;             /* see note below */
        if (db == NULL) {
                if (errno == ENOENT) {
#ifdef DEBUG
                        yplog("  ypdb_open_db: no map %s (domain=%s)",
                            map, domain);
#endif
                        return(NULL);
                }
#ifdef DEBUG
                yplog("  ypdb_open_db: ypdb_open FAILED: map %s (domain=%s)",
                    map, domain);
#endif
                return(NULL);
        }

        /*
         * note: status now YP_NOMAP
         */

        if (d == NULL) {                /* allocate new domain? */
                d = malloc(sizeof(*d));
                if (d)
                        d->domain = strdup(domain);
                if (d == NULL || d->domain == NULL) {
                        yplog("  ypdb_open_db: MALLOC failed");
                        ypdb_close(db);
                        free(d);
                        return(NULL);
                }
                LIST_INIT(&d->dmaps);
                LIST_INSERT_HEAD(&doms, d, domsl);
#ifdef DEBUG
                yplog("  ypdb_open_db: NEW DOMAIN %s", domain);
#endif
        }

        /*
         * m must be NULL since we couldn't find a map.  allocate new one
         */

        m = malloc(sizeof(*m));
        if (m)
                m->map = strdup(map);
        if (m == NULL || m->map == NULL) {
                free(m);
                yplog("  ypdb_open_db: MALLOC failed");
                ypdb_close(db);
                return(NULL);
        }
        m->db = db;
        m->dom = d;
        m->host_lookup = FALSE;
        TAILQ_INSERT_HEAD(&maps, m, mapsq);
        LIST_INSERT_HEAD(&d->dmaps, m, mapsl);
        if (strcmp(map, YP_HOSTNAME) == 0 || strcmp(map, YP_HOSTADDR) == 0) {
                if (!usedns) {
                        k.dptr = domain_key;
                        k.dsize = YP_INTERDOMAIN_LEN;
                        v = ypdb_fetch(db, k);
                        if (v.dptr)
                                m->host_lookup = TRUE;
                } else
                        m->host_lookup = TRUE;
        }
        m->secure = FALSE;
        k.dptr = secure_key;
        k.dsize = YP_SECURE_LEN;
        v = ypdb_fetch(db, k);
        if (v.dptr)
                m->secure = TRUE;
        *status = YP_TRUE;
        if (map_info)
                *map_info = m;
#ifdef DEBUG
        yplog("  ypdb_open_db: NEW MAP domain=%s, map=%s, hl=%d, s=%d, db=0x%x",
            domain, map, m->host_lookup, m->secure, m->db);
#endif
        return(m->db);
}

/*
 * lookup host
 */
static ypstat
lookup_host(int nametable, int host_lookup, DBM *db, char *keystr,
    ypresp_val *result)
{
        struct hostent *host;
        struct in_addr *addr_name;
        struct in_addr addr_addr;
        static char val[BUFSIZ+1]; /* match libc */
        static char hostname[HOST_NAME_MAX+1];
        char tmpbuf[HOST_NAME_MAX+1 + 20], *v, *ptr;
        size_t len;
        int l;

        if (!host_lookup)
                return(YP_NOKEY);

        if ((_res.options & RES_INIT) == 0)
                res_init();
        bcopy("b", _res.lookups, sizeof("b"));

        if (nametable) {
                host = gethostbyname(keystr);
                if (host == NULL || host->h_addrtype != AF_INET)
                        return(YP_NOKEY);
                addr_name = (struct in_addr *) *host->h_addr_list;
                v = val;
                for (; host->h_addr_list[0] != NULL; host->h_addr_list++) {
                        addr_name = (struct in_addr *)host->h_addr_list[0];
                        snprintf(tmpbuf, sizeof(tmpbuf), "%s %s\n",
                            inet_ntoa(*addr_name), host->h_name);
                        len = strlcat(val, tmpbuf, sizeof(val));
                        if (len >= sizeof(val))
                                break;
                        v = val + len;
                }
                result->val.valdat_val = val;
                result->val.valdat_len = v - val;
                return(YP_TRUE);
        }

        inet_aton(keystr, &addr_addr);
        host = gethostbyaddr((char *)&addr_addr, sizeof(addr_addr), AF_INET);
        if (host == NULL) return(YP_NOKEY);

        strncpy((char *)hostname, host->h_name, sizeof(hostname) - 1);
        hostname[sizeof(hostname) - 1] = '\0';
        host = gethostbyname((char *)hostname);
        if (host == NULL)
                return(YP_NOKEY);

        l = 0;
        for (; host->h_addr_list[0] != NULL; host->h_addr_list++)
                if (!bcmp(host->h_addr_list[0], &addr_addr, sizeof(addr_addr)))
                        l++;
        if (l == 0) {
                yplog("lookup_host: address %s not listed for host %s\n",
                    inet_ntoa(addr_addr), hostname);
                syslog(LOG_NOTICE,
                    "ypserv: address %s not listed for host %s\n",
                    inet_ntoa(addr_addr), hostname);
                return(YP_NOKEY);
        }

        len = snprintf(val, sizeof(val), "%s %s", keystr, host->h_name);
        if (len < 0 || len >= sizeof(val))
                return(YP_YPERR);
        v = val + len;
        while ((ptr = *(host->h_aliases)) != NULL) {
                strlcat(val, " ", sizeof(val));
                len = strlcat(val, ptr, sizeof(val));
                if (len >= sizeof(val))
                        break;
                v = val + len;
                host->h_aliases++;
        }
        result->val.valdat_val = val;
        result->val.valdat_len = v - val;

        return(YP_TRUE);
}

ypresp_val
ypdb_get_record(domainname domain, mapname map, keydat key, int ypprivate)
{
        static  ypresp_val res;
        static  char keystr[YPMAXRECORD+1];
        DBM     *db;
        datum   k, v;
        int     host_lookup = 0, hn;
        struct opt_map *map_info = NULL;

        bzero(&res, sizeof(res));

        db = ypdb_open_db(domain, map, &res.stat, &map_info);
        if (!db || res.stat < 0)
                return(res);
        if (map_info)
                host_lookup = map_info->host_lookup;

        k.dptr = key.keydat_val;
        k.dsize = key.keydat_len;

        if (yp_private(k, ypprivate)) {
                res.stat = YP_NOKEY;
                goto done;
        }

        v = ypdb_fetch(db, k);

        if (v.dptr == NULL) {
                res.stat = YP_NOKEY;
                if ((hn = strcmp(map, YP_HOSTNAME)) != 0 &&
                    strcmp(map, YP_HOSTADDR) != 0)
                        goto done;
                /* note: lookup_host needs null terminated string */
                strncpy(keystr, key.keydat_val, key.keydat_len);
                keystr[key.keydat_len] = '\0';
                res.stat = lookup_host((hn == 0) ? TRUE : FALSE,
                    host_lookup, db, keystr, &res);
        } else {
                res.val.valdat_val = v.dptr;
                res.val.valdat_len = v.dsize;
        }

done:
        ypdb_close_db(db);
        return(res);
}

ypresp_key_val
ypdb_get_first(domainname domain, mapname map, int ypprivate)
{
        static ypresp_key_val res;
        DBM     *db;
        datum   k, v;

        bzero(&res, sizeof(res));

        db = ypdb_open_db(domain, map, &res.stat, NULL);

        if (res.stat >= 0) {
                k = ypdb_firstkey(db);

                while (yp_private(k, ypprivate))
                        k = ypdb_nextkey(db);

                if (k.dptr == NULL) {
                        res.stat = YP_NOKEY;
                } else {
                        res.key.keydat_val = k.dptr;
                        res.key.keydat_len = k.dsize;
                        v = ypdb_fetch(db, k);
                        if (v.dptr == NULL) {
                                res.stat = YP_NOKEY;
                        } else {
                                res.val.valdat_val = v.dptr;
                                res.val.valdat_len = v.dsize;
                        }
                }
        }
        ypdb_close_db(db);
        return (res);
}

ypresp_key_val
ypdb_get_next(domainname domain, mapname map, keydat key, int ypprivate)
{
        static ypresp_key_val res;
        DBM     *db;
        datum   k, v, n;

        bzero(&res, sizeof(res));
        db = ypdb_open_db(domain, map, &res.stat, NULL);

        if (res.stat >= 0) {
                n.dptr = key.keydat_val;
                n.dsize = key.keydat_len;
                v.dptr = NULL;
                v.dsize = 0;
                k.dptr = NULL;
                k.dsize = 0;

                n = ypdb_setkey(db, n);

                if (n.dptr != NULL)
                        k = ypdb_nextkey(db);
                else
                        k.dptr = NULL;

                if (k.dptr != NULL) {
                        while (yp_private(k, ypprivate))
                                k = ypdb_nextkey(db);
                }

                if (k.dptr == NULL) {
                        res.stat = YP_NOMORE;
                } else {
                        res.key.keydat_val = k.dptr;
                        res.key.keydat_len = k.dsize;
                        v = ypdb_fetch(db, k);
                        if (v.dptr == NULL) {
                                res.stat = YP_NOMORE;
                        } else {
                                res.val.valdat_val = v.dptr;
                                res.val.valdat_len = v.dsize;
                        }
                }
        }
        ypdb_close_db(db);
        return (res);
}

ypresp_order
ypdb_get_order(domainname domain, mapname map)
{
        static ypresp_order res;
        static char   *order_key = YP_LAST_KEY;
        char   order[MAX_LAST_LEN+1];
        DBM     *db;
        datum   k, v;

        bzero(&res, sizeof(res));
        db = ypdb_open_db(domain, map, &res.stat, NULL);

        if (res.stat >= 0) {
                k.dptr = order_key;
                k.dsize = YP_LAST_LEN;

                v = ypdb_fetch(db, k);
                if (v.dptr == NULL) {
                        res.stat = YP_NOKEY;
                } else {
                        strncpy(order, v.dptr, v.dsize);
                        order[v.dsize] = '\0';
                        res.ordernum = (u_int32_t)atol(order);
                }
        }
        ypdb_close_db(db);
        return (res);
}

ypresp_master
ypdb_get_master(domainname domain, mapname map)
{
        static ypresp_master res;
        static char   *master_key = YP_MASTER_KEY;
        static char   master[MAX_MASTER_LEN+1];
        DBM     *db;
        datum   k, v;

        bzero(&res, sizeof(res));
        db = ypdb_open_db(domain, map, &res.stat, NULL);

        if (res.stat >= 0) {
                k.dptr = master_key;
                k.dsize = YP_MASTER_LEN;

                v = ypdb_fetch(db, k);
                if (v.dptr == NULL) {
                        res.stat = YP_NOKEY;
                } else {
                        strncpy(master, v.dptr, v.dsize);
                        master[v.dsize] = '\0';
                        res.peer = (peername) &master;
                }
        }
        ypdb_close_db(db);
        return (res);
}

bool_t
ypdb_xdr_get_all(XDR *xdrs, ypreq_nokey *req)
{
        static ypresp_all resp;
        DBM     *db;
        datum   k, v;

        bzero(&resp, sizeof(resp));

        /*
         * open db, and advance past any private keys we may see
         */
        db = ypdb_open_db(req->domain, req->map,
            &resp.ypresp_all_u.val.stat, NULL);
        if (!db || resp.ypresp_all_u.val.stat < 0)
                return(FALSE);
        k = ypdb_firstkey(db);
        while (yp_private(k, FALSE))
                k = ypdb_nextkey(db);

        while (1) {
                if (k.dptr == NULL)
                        break;

                v = ypdb_fetch(db, k);
                if (v.dptr == NULL)
                        break;

                resp.more = TRUE;
                resp.ypresp_all_u.val.stat = YP_TRUE;
                resp.ypresp_all_u.val.key.keydat_val = k.dptr;
                resp.ypresp_all_u.val.key.keydat_len = k.dsize;
                resp.ypresp_all_u.val.val.valdat_val = v.dptr;
                resp.ypresp_all_u.val.val.valdat_len = v.dsize;

                if (!xdr_ypresp_all(xdrs, &resp)) {
#ifdef DEBUG
                        yplog("  ypdb_xdr_get_all: xdr_ypresp_all failed");
#endif
                        return(FALSE);
                }

                /* advance past private keys */
                k = ypdb_nextkey(db);
                while (yp_private(k, FALSE))
                        k = ypdb_nextkey(db);
        }

        bzero(&resp, sizeof(resp));
        resp.ypresp_all_u.val.stat = YP_NOKEY;
        resp.more = FALSE;

        if (!xdr_ypresp_all(xdrs, &resp)) {
#ifdef DEBUG
                yplog("  ypdb_xdr_get_all: final xdr_ypresp_all failed");
#endif
                return(FALSE);
        }
        ypdb_close_db(db);
        return (TRUE);
}

int
ypdb_secure(domainname domain, mapname map)
{
        static  ypresp_val res;
        DBM     *db;
        int     secure;
        struct opt_map *map_info = NULL;

        bzero(&res, sizeof(res));
        secure = FALSE;

        db = ypdb_open_db(domain, map, &res.stat, &map_info);
        if (!db || res.stat < 0)
                return(secure);                 /* ? */
        if (map_info)
                secure = map_info->secure;

        ypdb_close_db(db);
        return(secure);
}