/*
 * 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 (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
 */


/*
 * Door server routines for nfsmapid daemon
 * Translate NFSv4 users and groups between numeric and string values
 */
#include <stdio.h>
#include <stdlib.h>
#include <alloca.h>
#include <signal.h>
#include <libintl.h>
#include <limits.h>
#include <errno.h>
#include <sys/types.h>
#include <string.h>
#include <memory.h>
#include <pwd.h>
#include <grp.h>
#include <door.h>
#include <syslog.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
#include <deflt.h>
#include <nfs/nfs4.h>
#include <nfs/nfssys.h>
#include <nfs/nfsid_map.h>
#include <nfs/mapid.h>
#include <sys/sdt.h>
#include <sys/idmap.h>
#include <idmap.h>
#include <sys/fs/autofs.h>
#include <sys/mkdev.h>
#include "nfs_resolve.h"

#define         UID_MAX_STR_LEN         11      /* Digits in UID_MAX + 1 */
#define         DIAG_FILE               "/var/run/nfs4_domain"

/*
 * idmap_kcall() takes a door descriptor as it's argument when we
 * need to (re)establish the in-kernel door handles. When we only
 * want to flush the id kernel caches, we don't redo the door setup.
 */
#define         FLUSH_KCACHES_ONLY      (int)-1

FILE            *n4_fp;
int              n4_fd;

extern size_t   pwd_buflen;
extern size_t   grp_buflen;
extern thread_t sig_thread;

/*
 * Prototypes
 */
extern void      check_domain(int);
extern void      idmap_kcall(int);
extern int       _nfssys(int, void *);
extern int       valid_domain(const char *);
extern int       validate_id_str(const char *);
extern int       extract_domain(char *, char **, char **);
extern void      update_diag_file(char *);
extern void     *cb_update_domain(void *);
extern int       cur_domain_null(void);

void
nfsmapid_str_uid(struct mapid_arg *argp, size_t arg_size)
{
        struct mapid_res result;
        struct passwd    pwd;
        struct passwd   *pwd_ptr;
        int              pwd_rc;
        char            *pwd_buf;
        char            *user;
        char            *domain;
        idmap_stat       rc;

        if (argp->u_arg.len <= 0 || arg_size < MAPID_ARG_LEN(argp->u_arg.len)) {
                result.status = NFSMAPID_INVALID;
                result.u_res.uid = UID_NOBODY;
                goto done;
        }

        if (!extract_domain(argp->str, &user, &domain)) {
                unsigned long id;

                /*
                 * Invalid "user@domain" string. Still, the user
                 * part might be an encoded uid, so do a final check.
                 * Remember, domain part of string was not set since
                 * not a valid string.
                 */
                if (!validate_id_str(user)) {
                        result.status = NFSMAPID_UNMAPPABLE;
                        result.u_res.uid = UID_NOBODY;
                        goto done;
                }

                errno = 0;
                id = strtoul(user, (char **)NULL, 10);

                /*
                 * We don't accept ephemeral ids from the wire.
                 */
                if (errno || id > UID_MAX) {
                        result.status = NFSMAPID_UNMAPPABLE;
                        result.u_res.uid = UID_NOBODY;
                        goto done;
                }

                result.u_res.uid = (uid_t)id;
                result.status = NFSMAPID_NUMSTR;
                goto done;
        }

        /*
         * String properly constructed. Now we check for domain and
         * group validity.
         */
        if (!cur_domain_null() && !valid_domain(domain)) {
                /*
                 * If the domain part of the string does not
                 * match the NFS domain, try to map it using
                 * idmap service.
                 */
                rc = idmap_getuidbywinname(user, domain, 0, &result.u_res.uid);
                if (rc != IDMAP_SUCCESS) {
                        result.status = NFSMAPID_BADDOMAIN;
                        result.u_res.uid = UID_NOBODY;
                        goto done;
                }
                result.status = NFSMAPID_OK;
                goto done;
        }

        if ((pwd_buf = malloc(pwd_buflen)) == NULL ||
            (pwd_rc = getpwnam_r(user, &pwd, pwd_buf, pwd_buflen, &pwd_ptr))
            != 0 || pwd_ptr == NULL) {

                if (pwd_buf == NULL || pwd_rc != 0)
                        result.status = NFSMAPID_INTERNAL;
                else {
                        /*
                         * Not a valid user
                         */
                        result.status = NFSMAPID_NOTFOUND;
                        free(pwd_buf);
                }
                result.u_res.uid = UID_NOBODY;
                goto done;
        }

        /*
         * Valid user entry
         */
        result.u_res.uid = pwd.pw_uid;
        result.status = NFSMAPID_OK;
        free(pwd_buf);
done:
        (void) door_return((char *)&result, sizeof (struct mapid_res), NULL, 0);
}

/* ARGSUSED1 */
void
nfsmapid_uid_str(struct mapid_arg *argp, size_t arg_size)
{
        struct mapid_res         result;
        struct mapid_res        *resp;
        struct passwd            pwd;
        struct passwd            *pwd_ptr;
        char                    *pwd_buf = NULL;
        char                    *idmap_buf = NULL;
        uid_t                    uid = argp->u_arg.uid;
        size_t                   uid_str_len;
        char                    *pw_str;
        size_t                   pw_str_len;
        char                    *at_str;
        size_t                   at_str_len;
        char                     dom_str[DNAMEMAX];
        size_t                   dom_str_len;
        idmap_stat               rc;

        if (uid == (uid_t)-1) {
                /*
                 * Sentinel uid is not a valid id
                 */
                resp = &result;
                resp->status = NFSMAPID_BADID;
                resp->u_res.len = 0;
                goto done;
        }

        /*
         * Make local copy of domain for further manipuation
         * NOTE: mapid_get_domain() returns a ptr to TSD.
         */
        if (cur_domain_null()) {
                dom_str_len = 0;
                dom_str[0] = '\0';
        } else {
                dom_str_len = strlcpy(dom_str, mapid_get_domain(), DNAMEMAX);
        }

        /*
         * If uid is ephemeral then resolve it using idmap service
         */
        if (uid > UID_MAX) {
                rc = idmap_getwinnamebyuid(uid, 0, &idmap_buf, NULL);
                if (rc != IDMAP_SUCCESS) {
                        /*
                         * We don't put stringified ephemeral uids on
                         * the wire.
                         */
                        resp = &result;
                        resp->status = NFSMAPID_UNMAPPABLE;
                        resp->u_res.len = 0;
                        goto done;
                }

                /*
                 * idmap_buf is already in the desired form i.e. name@domain
                 */
                pw_str = idmap_buf;
                pw_str_len = strlen(pw_str);
                at_str_len = dom_str_len = 0;
                at_str = "";
                dom_str[0] = '\0';
                goto gen_result;
        }

        /*
         * Handling non-ephemeral uids
         *
         * We want to encode the uid into a literal string... :
         *
         *      - upon failure to allocate space from the heap
         *      - if there is no current domain configured
         *      - if there is no such uid in the passwd DB's
         */
        if ((pwd_buf = malloc(pwd_buflen)) == NULL || dom_str_len == 0 ||
            getpwuid_r(uid, &pwd, pwd_buf, pwd_buflen, &pwd_ptr) != 0 ||
            pwd_ptr == NULL) {

                /*
                 * If we could not allocate from the heap, try
                 * allocating from the stack as a last resort.
                 */
                if (pwd_buf == NULL && (pwd_buf =
                    alloca(MAPID_RES_LEN(UID_MAX_STR_LEN))) == NULL) {
                        resp = &result;
                        resp->status = NFSMAPID_INTERNAL;
                        resp->u_res.len = 0;
                        goto done;
                }

                /*
                 * Constructing literal string without '@' so that
                 * we'll know that it's not a user, but rather a
                 * uid encoded string.
                 */
                pw_str = pwd_buf;
                (void) sprintf(pw_str, "%u", uid);
                pw_str_len = strlen(pw_str);
                at_str_len = dom_str_len = 0;
                at_str = "";
                dom_str[0] = '\0';
        } else {
                /*
                 * Otherwise, we construct the "user@domain" string if
                 * it's not already in that form.
                 */
                pw_str = pwd.pw_name;
                pw_str_len = strlen(pw_str);
                if (strchr(pw_str, '@') == NULL) {
                        at_str = "@";
                        at_str_len = 1;
                } else {
                        at_str_len = dom_str_len = 0;
                        at_str = "";
                        dom_str[0] = '\0';
                }
        }

gen_result:
        uid_str_len = pw_str_len + at_str_len + dom_str_len;
        if ((resp = alloca(MAPID_RES_LEN(uid_str_len))) == NULL) {
                resp = &result;
                resp->status = NFSMAPID_INTERNAL;
                resp->u_res.len = 0;
                goto done;
        }
        /* LINTED format argument to sprintf */
        (void) sprintf(resp->str, "%s%s%s", pw_str, at_str, dom_str);
        resp->u_res.len = uid_str_len;
        if (pwd_buf)
                free(pwd_buf);
        if (idmap_buf)
                idmap_free(idmap_buf);
        resp->status = NFSMAPID_OK;

done:
        /*
         * There is a chance that the door_return will fail because the
         * resulting string is too large, try to indicate that if possible
         */
        if (door_return((char *)resp,
            MAPID_RES_LEN(resp->u_res.len), NULL, 0) == -1) {
                resp->status = NFSMAPID_INTERNAL;
                resp->u_res.len = 0;
                (void) door_return((char *)&result, sizeof (struct mapid_res),
                    NULL, 0);
        }
}

void
nfsmapid_str_gid(struct mapid_arg *argp, size_t arg_size)
{
        struct mapid_res        result;
        struct group            grp;
        struct group            *grp_ptr;
        int                     grp_rc;
        char                    *grp_buf;
        char                    *group;
        char                    *domain;
        idmap_stat              rc;

        if (argp->u_arg.len <= 0 ||
            arg_size < MAPID_ARG_LEN(argp->u_arg.len)) {
                result.status = NFSMAPID_INVALID;
                result.u_res.gid = GID_NOBODY;
                goto done;
        }

        if (!extract_domain(argp->str, &group, &domain)) {
                unsigned long id;

                /*
                 * Invalid "group@domain" string. Still, the
                 * group part might be an encoded gid, so do a
                 * final check. Remember, domain part of string
                 * was not set since not a valid string.
                 */
                if (!validate_id_str(group)) {
                        result.status = NFSMAPID_UNMAPPABLE;
                        result.u_res.gid = GID_NOBODY;
                        goto done;
                }

                errno = 0;
                id = strtoul(group, (char **)NULL, 10);

                /*
                 * We don't accept ephemeral ids from the wire.
                 */
                if (errno || id > UID_MAX) {
                        result.status = NFSMAPID_UNMAPPABLE;
                        result.u_res.gid = GID_NOBODY;
                        goto done;
                }

                result.u_res.gid = (gid_t)id;
                result.status = NFSMAPID_NUMSTR;
                goto done;
        }

        /*
         * String properly constructed. Now we check for domain and
         * group validity.
         */
        if (!cur_domain_null() && !valid_domain(domain)) {
                /*
                 * If the domain part of the string does not
                 * match the NFS domain, try to map it using
                 * idmap service.
                 */
                rc = idmap_getgidbywinname(group, domain, 0, &result.u_res.gid);
                if (rc != IDMAP_SUCCESS) {
                        result.status = NFSMAPID_BADDOMAIN;
                        result.u_res.gid = GID_NOBODY;
                        goto done;
                }
                result.status = NFSMAPID_OK;
                goto done;
        }

        if ((grp_buf = malloc(grp_buflen)) == NULL ||
            (grp_rc = getgrnam_r(group, &grp, grp_buf, grp_buflen, &grp_ptr))
            != 0 || grp_ptr == NULL) {

                if (grp_buf == NULL || grp_rc != 0)
                        result.status = NFSMAPID_INTERNAL;
                else {
                        /*
                         * Not a valid group
                         */
                        result.status = NFSMAPID_NOTFOUND;
                        free(grp_buf);
                }
                result.u_res.gid = GID_NOBODY;
                goto done;
        }

        /*
         * Valid group entry
         */
        result.status = NFSMAPID_OK;
        result.u_res.gid = grp.gr_gid;
        free(grp_buf);
done:
        (void) door_return((char *)&result, sizeof (struct mapid_res), NULL, 0);
}

/* ARGSUSED1 */
void
nfsmapid_gid_str(struct mapid_arg *argp, size_t arg_size)
{
        struct mapid_res         result;
        struct mapid_res        *resp;
        struct group             grp;
        struct group            *grp_ptr;
        char                    *grp_buf = NULL;
        char                    *idmap_buf = NULL;
        idmap_stat               rc;
        gid_t                    gid = argp->u_arg.gid;
        size_t                   gid_str_len;
        char                    *gr_str;
        size_t                   gr_str_len;
        char                    *at_str;
        size_t                   at_str_len;
        char                     dom_str[DNAMEMAX];
        size_t                   dom_str_len;

        if (gid == (gid_t)-1) {
                /*
                 * Sentinel gid is not a valid id
                 */
                resp = &result;
                resp->status = NFSMAPID_BADID;
                resp->u_res.len = 0;
                goto done;
        }

        /*
         * Make local copy of domain for further manipuation
         * NOTE: mapid_get_domain() returns a ptr to TSD.
         */
        if (cur_domain_null()) {
                dom_str_len = 0;
                dom_str[0] = '\0';
        } else {
                dom_str_len = strlen(mapid_get_domain());
                bcopy(mapid_get_domain(), dom_str, dom_str_len);
                dom_str[dom_str_len] = '\0';
        }

        /*
         * If gid is ephemeral then resolve it using idmap service
         */
        if (gid > UID_MAX) {
                rc = idmap_getwinnamebygid(gid, 0, &idmap_buf, NULL);
                if (rc != IDMAP_SUCCESS) {
                        /*
                         * We don't put stringified ephemeral gids on
                         * the wire.
                         */
                        resp = &result;
                        resp->status = NFSMAPID_UNMAPPABLE;
                        resp->u_res.len = 0;
                        goto done;
                }

                /*
                 * idmap_buf is already in the desired form i.e. name@domain
                 */
                gr_str = idmap_buf;
                gr_str_len = strlen(gr_str);
                at_str_len = dom_str_len = 0;
                at_str = "";
                dom_str[0] = '\0';
                goto gen_result;
        }

        /*
         * Handling non-ephemeral gids
         *
         * We want to encode the gid into a literal string... :
         *
         *      - upon failure to allocate space from the heap
         *      - if there is no current domain configured
         *      - if there is no such gid in the group DB's
         */
        if ((grp_buf = malloc(grp_buflen)) == NULL || dom_str_len == 0 ||
            getgrgid_r(gid, &grp, grp_buf, grp_buflen, &grp_ptr) != 0 ||
            grp_ptr == NULL) {

                /*
                 * If we could not allocate from the heap, try
                 * allocating from the stack as a last resort.
                 */
                if (grp_buf == NULL && (grp_buf =
                    alloca(MAPID_RES_LEN(UID_MAX_STR_LEN))) == NULL) {
                        resp = &result;
                        resp->status = NFSMAPID_INTERNAL;
                        resp->u_res.len = 0;
                        goto done;
                }

                /*
                 * Constructing literal string without '@' so that
                 * we'll know that it's not a group, but rather a
                 * gid encoded string.
                 */
                gr_str = grp_buf;
                (void) sprintf(gr_str, "%u", gid);
                gr_str_len = strlen(gr_str);
                at_str_len = dom_str_len = 0;
                at_str = "";
                dom_str[0] = '\0';
        } else {
                /*
                 * Otherwise, we construct the "group@domain" string if
                 * it's not already in that form.
                 */
                gr_str = grp.gr_name;
                gr_str_len = strlen(gr_str);
                if (strchr(gr_str, '@') == NULL) {
                        at_str = "@";
                        at_str_len = 1;
                } else {
                        at_str_len = dom_str_len = 0;
                        at_str = "";
                        dom_str[0] = '\0';
                }
        }

gen_result:
        gid_str_len = gr_str_len + at_str_len + dom_str_len;
        if ((resp = alloca(MAPID_RES_LEN(gid_str_len))) == NULL) {
                resp = &result;
                resp->status = NFSMAPID_INTERNAL;
                resp->u_res.len = 0;
                goto done;
        }
        /* LINTED format argument to sprintf */
        (void) sprintf(resp->str, "%s%s%s", gr_str, at_str, dom_str);
        resp->u_res.len = gid_str_len;
        if (grp_buf)
                free(grp_buf);
        if (idmap_buf)
                idmap_free(idmap_buf);
        resp->status = NFSMAPID_OK;

done:
        /*
         * There is a chance that the door_return will fail because the
         * resulting string is too large, try to indicate that if possible
         */
        if (door_return((char *)resp,
            MAPID_RES_LEN(resp->u_res.len), NULL, 0) == -1) {
                resp->status = NFSMAPID_INTERNAL;
                resp->u_res.len = 0;
                (void) door_return((char *)&result, sizeof (struct mapid_res),
                    NULL, 0);
        }
}

void
nfsmapid_server_netinfo(refd_door_args_t *referral_args, size_t arg_size)
{
        char *res;
        int res_size;
        int error;
        int srsz = 0;
        char host[MAXHOSTNAMELEN];
        utf8string      *nfsfsloc_args;
        refd_door_res_t *door_res;
        refd_door_res_t failed_res;
        struct nfs_fsl_info *nfs_fsloc_res;

        if (arg_size < sizeof (refd_door_args_t)) {
                failed_res.res_status = EINVAL;
                res = (char *)&failed_res;
                res_size = sizeof (refd_door_res_t);
                syslog(LOG_ERR,
                    "nfsmapid_server_netinfo failed: Invalid data\n");
                goto send_response;
        }

        if (decode_args(xdr_utf8string, (refd_door_args_t *)referral_args,
            (caddr_t *)&nfsfsloc_args, sizeof (utf8string))) {
                syslog(LOG_ERR, "cannot allocate memory");
                failed_res.res_status = ENOMEM;
                failed_res.xdr_len = 0;
                res = (caddr_t)&failed_res;
                res_size = sizeof (refd_door_res_t);
                goto send_response;
        }

        if (nfsfsloc_args->utf8string_len >= MAXHOSTNAMELEN) {
                syslog(LOG_ERR, "argument too large");
                failed_res.res_status = EOVERFLOW;
                failed_res.xdr_len = 0;
                res = (caddr_t)&failed_res;
                res_size = sizeof (refd_door_res_t);
                goto send_response;
        }

        snprintf(host, nfsfsloc_args->utf8string_len + 1,
            "%s", nfsfsloc_args->utf8string_val);

        nfs_fsloc_res =
            get_nfs4ref_info(host, NFS_PORT, NFS_V4);

        xdr_free(xdr_utf8string, (char *)&nfsfsloc_args);

        if (nfs_fsloc_res) {
                error = 0;
                error = encode_res(xdr_nfs_fsl_info, &door_res,
                    (caddr_t)nfs_fsloc_res, &res_size);
                free_nfs4ref_info(nfs_fsloc_res);
                if (error != 0) {
                        syslog(LOG_ERR,
                            "error allocating fs_locations "
                            "results buffer");
                        failed_res.res_status = error;
                        failed_res.xdr_len = srsz;
                        res = (caddr_t)&failed_res;
                        res_size = sizeof (refd_door_res_t);
                } else {
                        door_res->res_status = 0;
                        res = (caddr_t)door_res;
                }
        } else {
                failed_res.res_status = EINVAL;
                failed_res.xdr_len = 0;
                res = (caddr_t)&failed_res;
                res_size = sizeof (refd_door_res_t);
        }

send_response:
        srsz = res_size;
        errno = 0;

        error = door_return(res, res_size, NULL, 0);
        if (errno == E2BIG) {
                failed_res.res_status = EOVERFLOW;
                failed_res.xdr_len = srsz;
                res = (caddr_t)&failed_res;
                res_size = sizeof (refd_door_res_t);
        } else {
                res = NULL;
                res_size = 0;
        }

        door_return(res, res_size, NULL, 0);
}

/* ARGSUSED */
void
nfsmapid_func(void *cookie, char *argp, size_t arg_size,
                                                door_desc_t *dp, uint_t n_desc)
{
        struct mapid_arg        *mapargp;
        struct mapid_res        mapres;
        refd_door_args_t        *referral_args;

        /*
         * Make sure we have a valid argument
         */
        if (arg_size < sizeof (struct mapid_arg)) {
                mapres.status = NFSMAPID_INVALID;
                mapres.u_res.len = 0;
                (void) door_return((char *)&mapres, sizeof (struct mapid_res),
                    NULL, 0);
                return;
        }

        /* LINTED pointer cast */
        mapargp = (struct mapid_arg *)argp;
        referral_args = (refd_door_args_t *)argp;
        switch (mapargp->cmd) {
        case NFSMAPID_STR_UID:
                nfsmapid_str_uid(mapargp, arg_size);
                return;
        case NFSMAPID_UID_STR:
                nfsmapid_uid_str(mapargp, arg_size);
                return;
        case NFSMAPID_STR_GID:
                nfsmapid_str_gid(mapargp, arg_size);
                return;
        case NFSMAPID_GID_STR:
                nfsmapid_gid_str(mapargp, arg_size);
                return;
        case NFSMAPID_SRV_NETINFO:
                nfsmapid_server_netinfo(referral_args, arg_size);
        default:
                break;
        }
        mapres.status = NFSMAPID_INVALID;
        mapres.u_res.len = 0;
        (void) door_return((char *)&mapres, sizeof (struct mapid_res), NULL, 0);
}

/*
 * mapid_get_domain() always returns a ptr to TSD, so the
 * check for a NULL domain is not a simple comparison with
 * NULL but we need to check the contents of the TSD data.
 */
int
cur_domain_null(void)
{
        char    *p;

        if ((p = mapid_get_domain()) == NULL)
                return (1);

        return (p[0] == '\0');
}

int
extract_domain(char *cp, char **upp, char **dpp)
{
        /*
         * Caller must insure that the string is valid
         */
        *upp = cp;

        if ((*dpp = strchr(cp, '@')) == NULL)
                return (0);
        *(*dpp)++ = '\0';
        return (1);
}

int
valid_domain(const char *dom)
{
        const char      *whoami = "valid_domain";

        if (!mapid_stdchk_domain(dom)) {
                syslog(LOG_ERR, gettext("%s: Invalid inbound domain name %s."),
                    whoami, dom);
                return (0);
        }

        /*
         * NOTE: mapid_get_domain() returns a ptr to TSD.
         */
        return (strcasecmp(dom, mapid_get_domain()) == 0);
}

int
validate_id_str(const char *id)
{
        while (*id) {
                if (!isdigit(*id++))
                        return (0);
        }
        return (1);
}

void
idmap_kcall(int door_id)
{
        struct nfsidmap_args args;

        if (door_id >= 0) {
                args.state = 1;
                args.did = door_id;
        } else {
                args.state = 0;
                args.did = 0;
        }
        (void) _nfssys(NFS_IDMAP, &args);
}

/*
 * Get the current NFS domain.
 *
 * If nfsmapid_domain is set in NFS SMF, then it is the NFS domain;
 * otherwise, the DNS domain is used.
 */
void
check_domain(int sighup)
{
        const char      *whoami = "check_domain";
        static int       setup_done = 0;
        static cb_t      cb;

        /*
         * Construct the arguments to be passed to libmapid interface
         * If called in response to a SIGHUP, reset any cached DNS TXT
         * RR state.
         */
        cb.fcn = cb_update_domain;
        cb.signal = sighup;
        mapid_reeval_domain(&cb);

        /*
         * Restart the signal handler thread if we're still setting up
         */
        if (!setup_done) {
                setup_done = 1;
                if (thr_continue(sig_thread)) {
                        syslog(LOG_ERR, gettext("%s: Fatal error: signal "
                            "handler thread could not be restarted."), whoami);
                        exit(6);
                }
        }
}

/*
 * Need to be able to open the DIAG_FILE before nfsmapid(8)
 * releases it's root priviledges. The DIAG_FILE then remains
 * open for the duration of this nfsmapid instance via n4_fd.
 */
void
open_diag_file()
{
        static int      msg_done = 0;

        if ((n4_fp = fopen(DIAG_FILE, "w+")) != NULL) {
                n4_fd = fileno(n4_fp);
                return;
        }

        if (msg_done)
                return;

        syslog(LOG_ERR, "Failed to create %s. Enable syslog "
            "daemon.debug for more info", DIAG_FILE);
        msg_done = 1;
}

/*
 * When a new domain name is configured, save to DIAG_FILE
 * and log to syslog, with LOG_DEBUG level (if configured).
 */
void
update_diag_file(char *new)
{
        char    buf[DNAMEMAX];
        ssize_t n;
        size_t  len;

        (void) lseek(n4_fd, (off_t)0, SEEK_SET);
        (void) ftruncate(n4_fd, 0);
        (void) snprintf(buf, DNAMEMAX, "%s\n", new);

        len = strlen(buf);
        n = write(n4_fd, buf, len);
        if (n < 0 || n < len)
                syslog(LOG_DEBUG, "Could not write %s to diag file", new);
        (void) fsync(n4_fd);

        syslog(LOG_DEBUG, "nfsmapid domain = %s", new);
}

/*
 * Callback function for libmapid. This will be called
 * by the lib, everytime the nfsmapid(8) domain changes.
 */
void *
cb_update_domain(void *arg)
{
        char    *new_dname = (char *)arg;

        DTRACE_PROBE1(nfsmapid, daemon__domain, new_dname);
        update_diag_file(new_dname);
        idmap_kcall(FLUSH_KCACHES_ONLY);

        return (NULL);
}

bool_t
xdr_utf8string(XDR *xdrs, utf8string *objp)
{
        if (xdrs->x_op != XDR_FREE)
                return (xdr_bytes(xdrs, (char **)&objp->utf8string_val,
                    (uint_t *)&objp->utf8string_len, NFS4_MAX_UTF8STRING));
        return (TRUE);
}


int
decode_args(xdrproc_t xdrfunc, refd_door_args_t *argp, caddr_t *xdrargs,
    int size)
{
        XDR xdrs;

        caddr_t tmpargs = (caddr_t)&((refd_door_args_t *)argp)->xdr_arg;
        size_t arg_size = ((refd_door_args_t *)argp)->xdr_len;

        xdrmem_create(&xdrs, tmpargs, arg_size, XDR_DECODE);

        *xdrargs = calloc(1, size);
        if (*xdrargs == NULL) {
                syslog(LOG_ERR, "error allocating arguments buffer");
                return (ENOMEM);
        }

        if (!(*xdrfunc)(&xdrs, *xdrargs)) {
                free(*xdrargs);
                *xdrargs = NULL;
                syslog(LOG_ERR, "error decoding arguments");
                return (EINVAL);
        }

        return (0);
}

int
encode_res(
        xdrproc_t xdrfunc,
        refd_door_res_t **results,
        caddr_t resp,
        int *size)
{
        XDR xdrs;

        *size = xdr_sizeof((*xdrfunc), resp);
        *results = malloc(sizeof (refd_door_res_t) + *size);
        if (*results == NULL) {
                return (ENOMEM);
        }
        (*results)->xdr_len = *size;
        *size = sizeof (refd_door_res_t) + (*results)->xdr_len;
        xdrmem_create(&xdrs, (caddr_t)((*results)->xdr_res),
            (*results)->xdr_len, XDR_ENCODE);
        if (!(*xdrfunc)(&xdrs, resp)) {
                (*results)->res_status = EINVAL;
                syslog(LOG_ERR, "error encoding results");
                return ((*results)->res_status);
        }
        (*results)->res_status = 0;
        return ((*results)->res_status);
}


bool_t
xdr_knetconfig(XDR *xdrs, struct knetconfig *objp)
{
        rpc_inline_t *buf;
        int i;
        u_longlong_t dev64;
#if !defined(_LP64)
        uint32_t major, minor;
#endif

        if (!xdr_u_int(xdrs, &objp->knc_semantics))
                return (FALSE);
        if (!xdr_opaque(xdrs, objp->knc_protofmly, KNC_STRSIZE))
                return (FALSE);
        if (!xdr_opaque(xdrs, objp->knc_proto, KNC_STRSIZE))
                return (FALSE);

        /*
         * For interoperability between 32-bit daemon and 64-bit kernel,
         * we always treat dev_t as 64-bit number and do the expanding
         * or compression of dev_t as needed.
         * We have to hand craft the conversion since there is no available
         * function in ddi.c. Besides ddi.c is available only in the kernel
         * and we want to keep both user and kernel of xdr_knetconfig() the
         * same for consistency.
         */

        if (xdrs->x_op == XDR_ENCODE) {
#if defined(_LP64)
                dev64 = objp->knc_rdev;
#else
                major = (objp->knc_rdev >> NBITSMINOR32) & MAXMAJ32;
                minor = objp->knc_rdev & MAXMIN32;
                dev64 = (((unsigned long long)major) << NBITSMINOR64) | minor;
#endif
                if (!xdr_u_longlong_t(xdrs, &dev64))
                        return (FALSE);
        }
        if (xdrs->x_op == XDR_DECODE) {
#if defined(_LP64)
                if (!xdr_u_longlong_t(xdrs, (u_longlong_t *)&objp->knc_rdev))
                        return (FALSE);
#else
                if (!xdr_u_longlong_t(xdrs, &dev64))
                        return (FALSE);

                major = (dev64 >> NBITSMINOR64) & L_MAXMAJ32;
                minor = dev64 & L_MAXMIN32;
                objp->knc_rdev = (major << L_BITSMINOR32) | minor;
#endif
        }

        if (xdrs->x_op == XDR_ENCODE) {
                buf = XDR_INLINE(xdrs, (8) * BYTES_PER_XDR_UNIT);
                if (buf == NULL) {
                        if (!xdr_vector(xdrs, (char *)objp->knc_unused, 8,
                            sizeof (uint_t), (xdrproc_t)xdr_u_int))
                                return (FALSE);
                } else {
                        uint_t *genp;

                        for (i = 0, genp = objp->knc_unused;
                            i < 8; i++) {
#if defined(_LP64) || defined(_KERNEL)
                                IXDR_PUT_U_INT32(buf, *genp++);
#else
                                IXDR_PUT_U_LONG(buf, *genp++);
#endif
                        }
                }
                return (TRUE);
        } else if (xdrs->x_op == XDR_DECODE) {
                buf = XDR_INLINE(xdrs, (8) * BYTES_PER_XDR_UNIT);
                if (buf == NULL) {
                        if (!xdr_vector(xdrs, (char *)objp->knc_unused, 8,
                            sizeof (uint_t), (xdrproc_t)xdr_u_int))
                                return (FALSE);
                } else {
                        uint_t *genp;

                        for (i = 0, genp = objp->knc_unused;
                            i < 8; i++) {
#if defined(_LP64) || defined(_KERNEL)
                                *genp++ = IXDR_GET_U_INT32(buf);
#else
                                *genp++ = IXDR_GET_U_LONG(buf);
#endif
                        }
                }
                return (TRUE);
        }

        if (!xdr_vector(xdrs, (char *)objp->knc_unused, 8,
            sizeof (uint_t), (xdrproc_t)xdr_u_int))
                return (FALSE);
        return (TRUE);
}

/*
 * used by NFSv4 referrals to get info needed for NFSv4 referral mount.
 */
bool_t
xdr_nfs_fsl_info(XDR *xdrs, struct nfs_fsl_info *objp)
{

        if (!xdr_u_int(xdrs, &objp->netbuf_len))
                return (FALSE);
        if (!xdr_u_int(xdrs, &objp->netnm_len))
                return (FALSE);
        if (!xdr_u_int(xdrs, &objp->knconf_len))
                return (FALSE);
        if (!xdr_string(xdrs, &objp->netname, ~0))
                return (FALSE);
        if (!xdr_pointer(xdrs, (char **)&objp->addr, objp->netbuf_len,
            (xdrproc_t)xdr_netbuf))
                return (FALSE);
        if (!xdr_pointer(xdrs, (char **)&objp->knconf,
            objp->knconf_len, (xdrproc_t)xdr_knetconfig))
                return (FALSE);
        return (TRUE);
}