/*
 * Copyright 2009 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */


/*
 * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
 * Copyright (c) 1996-1999 by 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 ISC DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS.  IN NO EVENT SHALL ISC 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.
 */

/*! \file
 * \brief
 * this is the top level dispatcher
 *
 * The dispatcher is implemented as an accessor class; it is an
 * accessor class that calls other accessor classes, as controlled by a
 * configuration file.
 *
 * A big difference between this accessor class and others is that the
 * map class initializers are NULL, and the map classes are already
 * filled in with method functions that will do the right thing.
 */

/* Imports */

#include "port_before.h"

#include <isc/assertions.h>
#include <ctype.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <netinet/in.h>
#include <arpa/nameser.h>
#include <resolv.h>

#include <isc/memcluster.h>
#include <irs.h>

#include "port_after.h"

#include "irs_p.h"
#include "gen_p.h"

#ifdef SUNW_HOSTS_FALLBACK
extern int __res_no_hosts_fallback(void);
#endif /* SUNW_HOSTS_FALLBACK */

/* Definitions */

struct nameval {
        const char *    name;
        int             val;
};

static const struct nameval acc_names[irs_nacc+1] = {
        { "local", irs_lcl },
        { "dns", irs_dns },
        { "nis", irs_nis },
        { "irp", irs_irp },
        { NULL, irs_nacc }
};

typedef struct irs_acc *(*accinit) __P((const char *options));

static const accinit accs[irs_nacc+1] = {
        irs_lcl_acc,
        irs_dns_acc,
#ifdef WANT_IRS_NIS
        irs_nis_acc,
#else
        NULL,
#endif
        irs_irp_acc,
        NULL
};

static const struct nameval map_names[irs_nmap+1] = {
        { "group", irs_gr },
        { "passwd", irs_pw },
        { "services", irs_sv },
        { "protocols", irs_pr },
        { "hosts", irs_ho },
        { "networks", irs_nw },
        { "netgroup", irs_ng },
        { NULL, irs_nmap }
};

static const struct nameval option_names[] = {
        { "merge", IRS_MERGE },
        { "continue", IRS_CONTINUE },
        { NULL, 0 }
};

/* Forward */

static void             gen_close(struct irs_acc *);
static struct __res_state * gen_res_get(struct irs_acc *);
static void             gen_res_set(struct irs_acc *, struct __res_state *,
                                    void (*)(void *));
static int              find_name(const char *, const struct nameval nv[]);
static void             init_map_rules(struct gen_p *, const char *conf_file);
static struct irs_rule *release_rule(struct irs_rule *);
static int              add_rule(struct gen_p *,
                                 enum irs_map_id, enum irs_acc_id,
                                 const char *);

/* Public */

struct irs_acc *
irs_gen_acc(const char *options, const char *conf_file) {
        struct irs_acc *acc;
        struct gen_p *irs;

        if (!(acc = memget(sizeof *acc))) {
                errno = ENOMEM;
                return (NULL);
        }
        memset(acc, 0x5e, sizeof *acc);
        if (!(irs = memget(sizeof *irs))) {
                errno = ENOMEM;
                memput(acc, sizeof *acc);
                return (NULL);
        }
        memset(irs, 0x5e, sizeof *irs);
        irs->options = strdup(options);
        irs->res = NULL;
        irs->free_res = NULL;
        memset(irs->accessors, 0, sizeof irs->accessors);
        memset(irs->map_rules, 0, sizeof irs->map_rules);
        init_map_rules(irs, conf_file);
        acc->private = irs;
#ifdef WANT_IRS_GR
        acc->gr_map = irs_gen_gr;
#else
        acc->gr_map = NULL;
#endif
#ifdef WANT_IRS_PW
        acc->pw_map = irs_gen_pw;
#else
        acc->pw_map = NULL;
#endif
        acc->sv_map = irs_gen_sv;
        acc->pr_map = irs_gen_pr;
        acc->ho_map = irs_gen_ho;
        acc->nw_map = irs_gen_nw;
        acc->ng_map = irs_gen_ng;
        acc->res_get = gen_res_get;
        acc->res_set = gen_res_set;
        acc->close = gen_close;
        return (acc);
}

/* Methods */

static struct __res_state *
gen_res_get(struct irs_acc *this) {
        struct gen_p *irs = (struct gen_p *)this->private;

        if (irs->res == NULL) {
                struct __res_state *res;
                res = (struct __res_state *)malloc(sizeof *res);
                if (res == NULL)
                        return (NULL);
                memset(res, 0, sizeof *res);
                gen_res_set(this, res, free);
        }

        if (((irs->res->options & RES_INIT) == 0U) && res_ninit(irs->res) < 0)
                return (NULL);

        return (irs->res);
}

static void
gen_res_set(struct irs_acc *this, struct __res_state *res,
            void (*free_res)(void *)) {
        struct gen_p *irs = (struct gen_p *)this->private;
#if 0
        struct irs_rule *rule;
        struct irs_ho *ho;
        struct irs_nw *nw;
#endif

        if (irs->res && irs->free_res) {
                res_nclose(irs->res);
                (*irs->free_res)(irs->res);
        }

        irs->res = res;
        irs->free_res = free_res;

#if 0
        for (rule = irs->map_rules[irs_ho]; rule; rule = rule->next) {
                ho = rule->inst->ho;

                (*ho->res_set)(ho, res, NULL);
        }
        for (rule = irs->map_rules[irs_nw]; rule; rule = rule->next) {
                nw = rule->inst->nw;

                (*nw->res_set)(nw, res, NULL);
        }
#endif
}

static void
gen_close(struct irs_acc *this) {
        struct gen_p *irs = (struct gen_p *)this->private;
        int n;

        /* Search rules. */
        for (n = 0; n < irs_nmap; n++)
                while (irs->map_rules[n] != NULL)
                        irs->map_rules[n] = release_rule(irs->map_rules[n]);

        /* Access methods. */
        for (n = 0; n < irs_nacc; n++) {
                /* Map objects. */
                if (irs->accessors[n].gr != NULL)
                        (*irs->accessors[n].gr->close)(irs->accessors[n].gr);
                if (irs->accessors[n].pw != NULL)
                        (*irs->accessors[n].pw->close)(irs->accessors[n].pw);
                if (irs->accessors[n].sv != NULL)
                        (*irs->accessors[n].sv->close)(irs->accessors[n].sv);
                if (irs->accessors[n].pr != NULL)
                        (*irs->accessors[n].pr->close)(irs->accessors[n].pr);
                if (irs->accessors[n].ho != NULL)
                        (*irs->accessors[n].ho->close)(irs->accessors[n].ho);
                if (irs->accessors[n].nw != NULL)
                        (*irs->accessors[n].nw->close)(irs->accessors[n].nw);
                if (irs->accessors[n].ng != NULL)
                        (*irs->accessors[n].ng->close)(irs->accessors[n].ng);
                /* Enclosing accessor. */
                if (irs->accessors[n].acc != NULL)
                        (*irs->accessors[n].acc->close)(irs->accessors[n].acc);
        }

        /* The options string was strdup'd. */
        free((void*)irs->options);

        if (irs->res && irs->free_res)
                (*irs->free_res)(irs->res);

        /* The private data container. */
        memput(irs, sizeof *irs);

        /* The object. */
        memput(this, sizeof *this);
}

/* Private */

static int
find_name(const char *name, const struct nameval names[]) {
        int n;

        for (n = 0; names[n].name != NULL; n++)
                if (strcmp(name, names[n].name) == 0)
                        return (names[n].val);
        return (-1);
}

static struct irs_rule *
release_rule(struct irs_rule *rule) {
        struct irs_rule *next = rule->next;

        memput(rule, sizeof *rule);
        return (next);
}

static int
add_rule(struct gen_p *irs,
         enum irs_map_id map, enum irs_acc_id acc,
         const char *options)
{
        struct irs_rule **rules, *last, *tmp, *new;
        struct irs_inst *inst;
        const char *cp;
        int n;

#ifndef WANT_IRS_GR
        if (map == irs_gr)
                return (-1);
#endif
#ifndef WANT_IRS_PW
        if (map == irs_pw)
                return (-1);
#endif
#ifndef WANT_IRS_NIS
        if (acc == irs_nis)
                return (-1);
#endif
        new = memget(sizeof *new);
        if (new == NULL)
                return (-1);
        memset(new, 0x5e, sizeof *new);
        new->next = NULL;

        new->inst = &irs->accessors[acc];

        new->flags = 0;
        cp = options;
        while (cp && *cp) {
                char option[50], *next;

                next = strchr(cp, ',');
                if (next)
                        n = next++ - cp;
                else
                        n = strlen(cp);
                if ((size_t)n > sizeof option - 1)
                        n = sizeof option - 1;
                strncpy(option, cp, n);
                option[n] = '\0';

                n = find_name(option, option_names);
                if (n >= 0)
                        new->flags |= n;

                cp = next;
        }

        rules = &irs->map_rules[map];
        for (last = NULL, tmp = *rules;
             tmp != NULL;
             last = tmp, tmp = tmp->next)
                (void)NULL;
        if (last == NULL)
                *rules = new;
        else
                last->next = new;

        /* Try to instantiate map accessors for this if necessary & approp. */
        inst = &irs->accessors[acc];
        if (inst->acc == NULL && accs[acc] != NULL)
                inst->acc = (*accs[acc])(irs->options);
        if (inst->acc != NULL) {
                if (inst->gr == NULL && inst->acc->gr_map != NULL)
                        inst->gr = (*inst->acc->gr_map)(inst->acc);
                if (inst->pw == NULL && inst->acc->pw_map != NULL)
                        inst->pw = (*inst->acc->pw_map)(inst->acc);
                if (inst->sv == NULL && inst->acc->sv_map != NULL)
                        inst->sv = (*inst->acc->sv_map)(inst->acc);
                if (inst->pr == NULL && inst->acc->pr_map != NULL)
                        inst->pr = (*inst->acc->pr_map)(inst->acc);
                if (inst->ho == NULL && inst->acc->ho_map != NULL)
                        inst->ho = (*inst->acc->ho_map)(inst->acc);
                if (inst->nw == NULL && inst->acc->nw_map != NULL)
                        inst->nw = (*inst->acc->nw_map)(inst->acc);
                if (inst->ng == NULL && inst->acc->ng_map != NULL)
                        inst->ng = (*inst->acc->ng_map)(inst->acc);
        }

        return (0);
}

static void
default_map_rules(struct gen_p *irs) {
        /* Install time honoured and proved BSD style rules as default. */
        add_rule(irs, irs_gr, irs_lcl, "");
        add_rule(irs, irs_pw, irs_lcl, "");
        add_rule(irs, irs_sv, irs_lcl, "");
        add_rule(irs, irs_pr, irs_lcl, "");
#ifdef SUNW_HOSTS_FALLBACK
        if (__res_no_hosts_fallback())
                add_rule(irs, irs_ho, irs_dns, "");
        else {
                add_rule(irs, irs_ho, irs_dns, "continue");
                add_rule(irs, irs_ho, irs_lcl, "");
        }
#else  /* SUNW_HOSTS_FALLBACK */
        add_rule(irs, irs_ho, irs_dns, "continue");
        add_rule(irs, irs_ho, irs_lcl, "");
#endif /* SUNW_HOSTS_FALLBACK */
        add_rule(irs, irs_nw, irs_dns, "continue");
        add_rule(irs, irs_nw, irs_lcl, "");
        add_rule(irs, irs_ng, irs_lcl, "");
}

static void
init_map_rules(struct gen_p *irs, const char *conf_file) {
        char line[1024], pattern[40], mapname[20], accname[20], options[100];
        FILE *conf;

#ifdef SUNW_HOSTS_FALLBACK
        if (__res_no_hosts_fallback()) {
                default_map_rules(irs);
                return;
        }
#endif /* SUNW_HOSTS_FALLBACK */

        if (conf_file == NULL)
                conf_file = _PATH_IRS_CONF ;

        /* A conf file of "" means compiled in defaults. Irpd wants this */
        if (conf_file[0] == '\0' || (conf = fopen(conf_file, "r")) == NULL) {
                default_map_rules(irs);
                return;
        }
        (void) sprintf(pattern, "%%%lus %%%lus %%%lus\n",
                       (unsigned long)sizeof mapname,
                       (unsigned long)sizeof accname,
                       (unsigned long)sizeof options);
        while (fgets(line, sizeof line, conf)) {
                enum irs_map_id map;
                enum irs_acc_id acc;
                char *tmp;
                int n;

                for (tmp = line;
                     isascii((unsigned char)*tmp) &&
                     isspace((unsigned char)*tmp);
                     tmp++)
                        (void)NULL;
                if (*tmp == '#' || *tmp == '\n' || *tmp == '\0')
                        continue;
                n = sscanf(tmp, pattern, mapname, accname, options);
                if (n < 2)
                        continue;
                if (n < 3)
                        options[0] = '\0';

                n = find_name(mapname, map_names);
                INSIST(n < irs_nmap);
                if (n < 0)
                        continue;
                map = (enum irs_map_id) n;

                n = find_name(accname, acc_names);
                INSIST(n < irs_nacc);
                if (n < 0)
                        continue;
                acc = (enum irs_acc_id) n;

                add_rule(irs, map, acc, options);
        }
        fclose(conf);
}