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

#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <ctype.h>

#define __NSS_PRIVATE_INTERFACE
#include "nsswitch_priv.h"
#undef  __NSS_PRIVATE_INTERFACE

#define islabel(c)      (isalnum(c) || (c) == '_')

/*
 * The _nsw_getoneconfig_v1() in this file parses the switch policy
 * configuration for a switch database, e.g.,
 *
 * hosts: nis [NOTFOUND=return] files
 * or
 * printers: user files nis
 */

/*
 * Local routines
 */
static char *skip(char **, char);
static char *labelskip(char *);
static char *spaceskip(char *);
static void freeconf_v1(struct __nsw_switchconfig_v1 *);
static int alldigits(char *);

/*
 *
 * With the "lookup control" feature, the default criteria for NIS
 * and any new services (e.g. ldap) will be:
 *     [SUCCESS=return  NOTFOUND=continue UNAVAIL=continue TRYAGAIN=forever]
 *
 * For backward compat, NIS via NIS server in DNS forwarding mode will be:
 *     [SUCCESS=return  NOTFOUND=continue UNAVAIL=continue TRYAGAIN=continue]
 *
 * And also for backward compat, the default criteria for DNS will be:
 *     [SUCCESS=return  NOTFOUND=continue UNAVAIL=continue TRYAGAIN=continue]
 */



/*
 * The BIND resolver normally will retry several times on server non-response.
 * But now with the "lookup control" feature, we don't want the resolver doing
 * many retries, rather we want it to return control (reasonably) quickly back
 * to the switch engine.  However, when TRYAGAIN=N or TRYAGAIN=forever is
 * not explicitly set by the admin in the conf file, we want the old "resolver
 * retry a few times" rather than no retries at all.
 */
static int      dns_tryagain_retry = 3;

/*
 * For backward compat (pre "lookup control"), the dns default behavior is
 * soft lookup.
 */
static void
set_dns_default_lkp(struct __nsw_lookup_v1 *lkp)
{
        if (strcasecmp(lkp->service_name, "dns") == 0) {
                lkp->actions[__NSW_TRYAGAIN] =
                    __NSW_TRYAGAIN_NTIMES;
                lkp->max_retries = dns_tryagain_retry;
        }
}

static void
freeconf_v1(struct __nsw_switchconfig_v1 *cfp)
{
        if (cfp) {
                if (cfp->dbase)
                        free(cfp->dbase);
                if (cfp->lookups) {
                        struct __nsw_lookup_v1 *nex, *cur;
                        for (cur = cfp->lookups; cur; cur = nex) {
                                free(cur->service_name);
                                nex = cur->next;
                                free(cur);
                        }
                }
                free(cfp);
        }
}

/* give the next non-alpha character */
static char *
labelskip(char *cur)
{
        char *p = cur;
        while (islabel(*p))
                ++p;
        return (p);
}

/* give the next non-space character */
static char *
spaceskip(char *cur)
{
        char *p = cur;
        while (*p == ' ' || *p == '\t')
                ++p;
        return (p);
}

/*
 * terminate the *cur pointed string by null only if it is
 * followed by "key" surrounded by zero or more spaces and
 * return value is the same as the original *cur pointer and
 * *cur pointer is advanced to the first non {space, key} char
 * followed by the key. Otherwise, return NULL and keep
 * *cur unchanged.
 */
static char *
skip(char **cur, char key)
{
        char *p, *tmp;
        char *q = *cur;
        int found, tmpfound;

        tmp = labelskip(*cur);
        p = tmp;
        found = (*p == key);
        if (found) {
                *p++ = '\0'; /* overwrite the key */
                p = spaceskip(p);
        } else {
                while (*p == ' ' || *p == '\t') {
                        tmpfound = (*++p == key);
                        if (tmpfound) {
                                found = tmpfound;
                                        /* null terminate the return token */
                                *tmp = '\0';
                                p++; /* skip the key */
                        }
                }
        }
        if (!found)
                return (NULL); /* *cur unchanged */
        *cur = p;
        return (q);
}

/* Return 1 if the string contains all digits, else return 0. */
static int
alldigits(char *s)
{
        for (; *s; s++)
                if (!isdigit(*s))
                        return (0);
        return (1);
}

struct __nsw_switchconfig_v1 *
_nsw_getoneconfig_v1(const char *name, char *linep, enum __nsw_parse_err *errp)
        /* linep   Nota Bene: not const char *  */
        /* errp  Meanings are abused a bit      */
{
        struct __nsw_switchconfig_v1 *cfp;
        struct __nsw_lookup_v1 *lkp, **lkq;
        int end_crit;
        action_t act;
        char *p, *tokenp;

        *errp = __NSW_CONF_PARSE_SUCCESS;

        if ((cfp = calloc(1, sizeof (struct __nsw_switchconfig_v1)))
            == NULL) {
                *errp = __NSW_CONF_PARSE_SYSERR;
                return (NULL);
        }
        cfp->dbase = strdup(name);
        lkq = &cfp->lookups;

        /* linep points to a naming service name */
        for (;;) {
                int i;

                /* white space following the last service */
                if (*linep == '\0' || *linep == '\n') {
                        return (cfp);
                }
                if ((lkp = calloc(1, sizeof (struct __nsw_lookup_v1)))
                    == NULL) {
                        *errp = __NSW_CONF_PARSE_SYSERR;
                        freeconf_v1(cfp);
                        return (NULL);
                }

                *lkq = lkp;
                lkq = &lkp->next;

                for (i = 0; i < __NSW_STD_ERRS_V1; i++)
                        if (i == __NSW_SUCCESS)
                                lkp->actions[i] = __NSW_RETURN;
                        else if (i == __NSW_TRYAGAIN)
                                lkp->actions[i] = __NSW_TRYAGAIN_FOREVER;
                        else
                                lkp->actions[i] = __NSW_CONTINUE;

                /* get criteria for the naming service */
                if (tokenp = skip(&linep, '[')) { /* got criteria */

                        /* premature end, illegal char following [ */
                        if (!islabel(*linep))
                                goto barf_line;
                        lkp->service_name = strdup(tokenp);
                        cfp->num_lookups++;

                        set_dns_default_lkp(lkp);

                        end_crit = 0;

                        /* linep points to a switch_err */
                        for (;;) {
                                int ntimes = 0; /* try again max N times */
                                int dns_continue = 0;

                                if ((tokenp = skip(&linep, '=')) == NULL) {
                                        goto barf_line;
                                }

                                /* premature end, ill char following = */
                                if (!islabel(*linep))
                                        goto barf_line;

                                /* linep points to the string following '=' */
                                p = labelskip(linep);
                                if (*p == ']')
                                        end_crit = 1;
                                else if (*p != ' ' && *p != '\t')
                                        goto barf_line;
                                *p++ = '\0'; /* null terminate linep */
                                p = spaceskip(p);
                                if (!end_crit) {
                                        if (*p == ']') {
                                        end_crit = 1;
                                        *p++ = '\0';
                                        } else if (*p == '\0' || *p == '\n') {
                                                return (cfp);
                                        } else if (!islabel(*p))
                                        /* p better be the next switch_err */
                                                goto barf_line;
                                }
                                if (strcasecmp(linep, __NSW_STR_RETURN) == 0)
                                        act = __NSW_RETURN;
                                else if (strcasecmp(linep,
                                                    __NSW_STR_CONTINUE) == 0) {
                                        if (strcasecmp(lkp->service_name,
                                                    "dns") == 0 &&
                                                strcasecmp(tokenp,
                                                        __NSW_STR_TRYAGAIN)
                                                        == 0) {
                                                /*
                                                 * Add one more condition
                                                 * so it retries only if it's
                                                 * "dns [TRYAGAIN=continue]"
                                                 */
                                                dns_continue = 1;
                                                act = __NSW_TRYAGAIN_NTIMES;
                                        } else
                                                act = __NSW_CONTINUE;
                                } else if (strcasecmp(linep,
                                            __NSW_STR_FOREVER) == 0)
                                        act = __NSW_TRYAGAIN_FOREVER;
                                else if (alldigits(linep)) {
                                        act = __NSW_TRYAGAIN_NTIMES;
                                        ntimes = atoi(linep);
                                        if (ntimes < 0 || ntimes > INT_MAX)
                                                ntimes = 0;
                                }
                                else
                                        goto barf_line;

                                if (__NSW_SUCCESS_ACTION(act) &&
                                    strcasecmp(tokenp,
                                            __NSW_STR_SUCCESS) == 0) {
                                        lkp->actions[__NSW_SUCCESS] = act;
                                } else if (__NSW_NOTFOUND_ACTION(act) &&
                                        strcasecmp(tokenp,
                                            __NSW_STR_NOTFOUND) == 0) {
                                        lkp->actions[__NSW_NOTFOUND] = act;
                                } else if (__NSW_UNAVAIL_ACTION(act) &&
                                        strcasecmp(tokenp,
                                            __NSW_STR_UNAVAIL) == 0) {
                                        lkp->actions[__NSW_UNAVAIL] = act;
                                } else if (__NSW_TRYAGAIN_ACTION(act) &&
                                        strcasecmp(tokenp,
                                            __NSW_STR_TRYAGAIN) == 0) {
                                        lkp->actions[__NSW_TRYAGAIN] = act;
                                        if (strcasecmp(lkp->service_name,
                                                    "nis") == 0)
                                                lkp->actions[
                                                    __NSW_NISSERVDNS_TRYAGAIN]
                                                    = act;
                                        if (act == __NSW_TRYAGAIN_NTIMES)
                                                lkp->max_retries =
                                                dns_continue ?
                                                dns_tryagain_retry : ntimes;
                                } else {
                                        /*EMPTY*/
                                        /*
                                         * convert string tokenp to integer
                                         * and put in long_errs
                                         */
                                }
                                if (end_crit) {
                                        linep = spaceskip(p);
                                        if (*linep == '\0' || *linep == '\n')
                                                return (cfp);
                                        break; /* process next naming service */
                                }
                                linep = p;
                        } /* end of while loop for a name service's criteria */
                } else {
                        /*
                         * no criteria for this naming service.
                         * linep points to name service, but not null
                         * terminated.
                         */
                        p = labelskip(linep);
                        if (*p == '\0' || *p == '\n') {
                                *p = '\0';
                                lkp->service_name = strdup(linep);
                                set_dns_default_lkp(lkp);
                                cfp->num_lookups++;
                                return (cfp);
                        }
                        if (*p != ' ' && *p != '\t')
                                goto barf_line;
                        *p++ = '\0';
                        lkp->service_name = strdup(linep);
                        set_dns_default_lkp(lkp);
                        cfp->num_lookups++;
                        linep = spaceskip(p);
                }
        } /* end of while(1) loop for a name service */

barf_line:
        freeconf_v1(cfp);
        *errp = __NSW_CONF_PARSE_NOPOLICY;
        return (NULL);
}

int
__nsw_freeconfig_v1(
        struct __nsw_switchconfig_v1 *conf)
{
        freeconf_v1(conf);
        return (0);
}