/*
 * Copyright (c) 1997 - 2008 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * 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.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``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 INSTITUTE OR CONTRIBUTORS 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.
 */

#include "krb5_locl.h"

#define KRB5_KT_VNO_1 1
#define KRB5_KT_VNO_2 2
#define KRB5_KT_VNO   KRB5_KT_VNO_2

#define KRB5_KT_FL_JAVA 1


/* file operations -------------------------------------------- */

struct fkt_data {
    char *filename;
    int flags;
};

static krb5_error_code
krb5_kt_ret_data(krb5_context context,
                 krb5_storage *sp,
                 krb5_data *data)
{
    int ret;
    int16_t size;
    ret = krb5_ret_int16(sp, &size);
    if(ret)
        return ret;
    data->length = size;
    data->data = malloc(size);
    if (data->data == NULL) {
        krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
        return ENOMEM;
    }
    ret = krb5_storage_read(sp, data->data, size);
    if(ret != size)
        return (ret < 0)? errno : KRB5_KT_END;
    return 0;
}

static krb5_error_code
krb5_kt_ret_string(krb5_context context,
                   krb5_storage *sp,
                   heim_general_string *data)
{
    int ret;
    int16_t size;
    ret = krb5_ret_int16(sp, &size);
    if(ret)
        return ret;
    *data = malloc(size + 1);
    if (*data == NULL) {
        krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
        return ENOMEM;
    }
    ret = krb5_storage_read(sp, *data, size);
    (*data)[size] = '\0';
    if(ret != size)
        return (ret < 0)? errno : KRB5_KT_END;
    return 0;
}

static krb5_error_code
krb5_kt_store_data(krb5_context context,
                   krb5_storage *sp,
                   krb5_data data)
{
    int ret;
    ret = krb5_store_int16(sp, data.length);
    if(ret < 0)
        return ret;
    ret = krb5_storage_write(sp, data.data, data.length);
    if(ret != (int)data.length){
        if(ret < 0)
            return errno;
        return KRB5_KT_END;
    }
    return 0;
}

static krb5_error_code
krb5_kt_store_string(krb5_storage *sp,
                     heim_general_string data)
{
    int ret;
    size_t len = strlen(data);
    ret = krb5_store_int16(sp, len);
    if(ret < 0)
        return ret;
    ret = krb5_storage_write(sp, data, len);
    if(ret != (int)len){
        if(ret < 0)
            return errno;
        return KRB5_KT_END;
    }
    return 0;
}

static krb5_error_code
krb5_kt_ret_keyblock(krb5_context context,
                     struct fkt_data *fkt,
                     krb5_storage *sp,
                     krb5_keyblock *p)
{
    int ret;
    int16_t tmp;

    ret = krb5_ret_int16(sp, &tmp); /* keytype + etype */
    if(ret)  {
        krb5_set_error_message(context, ret,
                               N_("Cant read keyblock from file %s", ""),
                               fkt->filename);
        return ret;
    }
    p->keytype = tmp;
    ret = krb5_kt_ret_data(context, sp, &p->keyvalue);
    if (ret)
        krb5_set_error_message(context, ret,
                               N_("Cant read keyblock from file %s", ""),
                               fkt->filename);
    return ret;
}

static krb5_error_code
krb5_kt_store_keyblock(krb5_context context,
                       struct fkt_data *fkt,
                       krb5_storage *sp,
                       krb5_keyblock *p)
{
    int ret;

    ret = krb5_store_int16(sp, p->keytype); /* keytype + etype */
    if(ret) {
        krb5_set_error_message(context, ret,
                               N_("Cant store keyblock to file %s", ""),
                               fkt->filename);
        return ret;
    }
    ret = krb5_kt_store_data(context, sp, p->keyvalue);
    if (ret)
        krb5_set_error_message(context, ret,
                               N_("Cant store keyblock to file %s", ""),
                               fkt->filename);
    return ret;
}


static krb5_error_code
krb5_kt_ret_principal(krb5_context context,
                      struct fkt_data *fkt,
                      krb5_storage *sp,
                      krb5_principal *princ)
{
    size_t i;
    int ret;
    krb5_principal p;
    int16_t len;

    ALLOC(p, 1);
    if(p == NULL) {
        krb5_set_error_message(context, ENOMEM,
                               N_("malloc: out of memory", ""));
        return ENOMEM;
    }

    ret = krb5_ret_int16(sp, &len);
    if(ret) {
        krb5_set_error_message(context, ret,
                               N_("Failed decoding length of "
                                  "keytab principal in keytab file %s", ""),
                               fkt->filename);
        goto out;
    }
    if(krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS))
        len--;
    if (len < 0) {
        ret = KRB5_KT_END;
        krb5_set_error_message(context, ret,
                               N_("Keytab principal contains "
                                  "invalid length in keytab %s", ""),
                               fkt->filename);
        goto out;
    }
    ret = krb5_kt_ret_string(context, sp, &p->realm);
    if(ret) {
        krb5_set_error_message(context, ret,
                               N_("Can't read realm from keytab: %s", ""),
                               fkt->filename);
        goto out;
    }
    p->name.name_string.val = calloc(len, sizeof(*p->name.name_string.val));
    if(p->name.name_string.val == NULL) {
        ret = ENOMEM;
        krb5_set_error_message(context, ret, N_("malloc: out of memory", ""));
        goto out;
    }
    p->name.name_string.len = len;
    for(i = 0; i < p->name.name_string.len; i++){
        ret = krb5_kt_ret_string(context, sp, p->name.name_string.val + i);
        if(ret) {
            krb5_set_error_message(context, ret,
                                   N_("Can't read principal from "
                                      "keytab: %s", ""),
                                   fkt->filename);
            goto out;
        }
    }
    if (krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE))
        p->name.name_type = KRB5_NT_UNKNOWN;
    else {
        int32_t tmp32;
        ret = krb5_ret_int32(sp, &tmp32);
        p->name.name_type = tmp32;
        if (ret) {
            krb5_set_error_message(context, ret,
                                   N_("Can't read name-type from "
                                      "keytab: %s", ""),
                                   fkt->filename);
            goto out;
        }
    }
    *princ = p;
    return 0;
out:
    krb5_free_principal(context, p);
    return ret;
}

static krb5_error_code
krb5_kt_store_principal(krb5_context context,
                        krb5_storage *sp,
                        krb5_principal p)
{
    size_t i;
    int ret;

    if(krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS))
        ret = krb5_store_int16(sp, p->name.name_string.len + 1);
    else
        ret = krb5_store_int16(sp, p->name.name_string.len);
    if(ret) return ret;
    ret = krb5_kt_store_string(sp, p->realm);
    if(ret) return ret;
    for(i = 0; i < p->name.name_string.len; i++){
        ret = krb5_kt_store_string(sp, p->name.name_string.val[i]);
        if(ret)
            return ret;
    }
    if(!krb5_storage_is_flags(sp, KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE)) {
        ret = krb5_store_int32(sp, p->name.name_type);
        if(ret)
            return ret;
    }

    return 0;
}

static krb5_error_code KRB5_CALLCONV
fkt_resolve(krb5_context context, const char *name, krb5_keytab id)
{
    struct fkt_data *d;

    d = malloc(sizeof(*d));
    if(d == NULL) {
        krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
        return ENOMEM;
    }
    d->filename = strdup(name);
    if(d->filename == NULL) {
        free(d);
        krb5_set_error_message(context, ENOMEM, N_("malloc: out of memory", ""));
        return ENOMEM;
    }
    d->flags = 0;
    id->data = d;
    return 0;
}

static krb5_error_code KRB5_CALLCONV
fkt_resolve_java14(krb5_context context, const char *name, krb5_keytab id)
{
    krb5_error_code ret;

    ret = fkt_resolve(context, name, id);
    if (ret == 0) {
        struct fkt_data *d = id->data;
        d->flags |= KRB5_KT_FL_JAVA;
    }
    return ret;
}

static krb5_error_code KRB5_CALLCONV
fkt_close(krb5_context context, krb5_keytab id)
{
    struct fkt_data *d = id->data;
    free(d->filename);
    free(d);
    return 0;
}

static krb5_error_code KRB5_CALLCONV
fkt_destroy(krb5_context context, krb5_keytab id)
{
    struct fkt_data *d = id->data;
    _krb5_erase_file(context, d->filename);
    return 0;
}

static krb5_error_code KRB5_CALLCONV
fkt_get_name(krb5_context context,
             krb5_keytab id,
             char *name,
             size_t namesize)
{
    /* This function is XXX */
    struct fkt_data *d = id->data;
    strlcpy(name, d->filename, namesize);
    return 0;
}

static void
storage_set_flags(krb5_context context, krb5_storage *sp, int vno)
{
    int flags = 0;
    switch(vno) {
    case KRB5_KT_VNO_1:
        flags |= KRB5_STORAGE_PRINCIPAL_WRONG_NUM_COMPONENTS;
        flags |= KRB5_STORAGE_PRINCIPAL_NO_NAME_TYPE;
        flags |= KRB5_STORAGE_HOST_BYTEORDER;
        break;
    case KRB5_KT_VNO_2:
        break;
    default:
        krb5_warnx(context,
                   "storage_set_flags called with bad vno (%d)", vno);
    }
    krb5_storage_set_flags(sp, flags);
}

static krb5_error_code
fkt_start_seq_get_int(krb5_context context,
                      krb5_keytab id,
                      int flags,
                      int exclusive,
                      krb5_kt_cursor *c)
{
    int8_t pvno, tag;
    krb5_error_code ret;
    struct fkt_data *d = id->data;

    c->fd = open (d->filename, flags);
    if (c->fd < 0) {
        ret = errno;
        krb5_set_error_message(context, ret,
                               N_("keytab %s open failed: %s", ""),
                               d->filename, strerror(ret));
        return ret;
    }
    rk_cloexec(c->fd);
    ret = _krb5_xlock(context, c->fd, exclusive, d->filename);
    if (ret) {
        close(c->fd);
        return ret;
    }
    c->sp = krb5_storage_from_fd(c->fd);
    if (c->sp == NULL) {
        _krb5_xunlock(context, c->fd);
        close(c->fd);
        krb5_set_error_message(context, ENOMEM,
                               N_("malloc: out of memory", ""));
        return ENOMEM;
    }
    krb5_storage_set_eof_code(c->sp, KRB5_KT_END);
    ret = krb5_ret_int8(c->sp, &pvno);
    if(ret) {
        krb5_storage_free(c->sp);
        _krb5_xunlock(context, c->fd);
        close(c->fd);
        krb5_clear_error_message(context);
        return ret;
    }
    if(pvno != 5) {
        krb5_storage_free(c->sp);
        _krb5_xunlock(context, c->fd);
        close(c->fd);
        krb5_clear_error_message (context);
        return KRB5_KEYTAB_BADVNO;
    }
    ret = krb5_ret_int8(c->sp, &tag);
    if (ret) {
        krb5_storage_free(c->sp);
        _krb5_xunlock(context, c->fd);
        close(c->fd);
        krb5_clear_error_message(context);
        return ret;
    }
    id->version = tag;
    storage_set_flags(context, c->sp, id->version);
    return 0;
}

static krb5_error_code KRB5_CALLCONV
fkt_start_seq_get(krb5_context context,
                  krb5_keytab id,
                  krb5_kt_cursor *c)
{
    return fkt_start_seq_get_int(context, id, O_RDONLY | O_BINARY | O_CLOEXEC, 0, c);
}

static krb5_error_code
fkt_next_entry_int(krb5_context context,
                   krb5_keytab id,
                   krb5_keytab_entry *entry,
                   krb5_kt_cursor *cursor,
                   off_t *start,
                   off_t *end)
{
    struct fkt_data *d = id->data;
    int32_t len;
    int ret;
    int8_t tmp8;
    int32_t tmp32;
    uint32_t utmp32;
    off_t pos, curpos;

    pos = krb5_storage_seek(cursor->sp, 0, SEEK_CUR);
loop:
    ret = krb5_ret_int32(cursor->sp, &len);
    if (ret)
        return ret;
    if(len < 0) {
        pos = krb5_storage_seek(cursor->sp, -len, SEEK_CUR);
        goto loop;
    }
    ret = krb5_kt_ret_principal (context, d, cursor->sp, &entry->principal);
    if (ret)
        goto out;
    ret = krb5_ret_uint32(cursor->sp, &utmp32);
    entry->timestamp = utmp32;
    if (ret)
        goto out;
    ret = krb5_ret_int8(cursor->sp, &tmp8);
    if (ret)
        goto out;
    entry->vno = tmp8;
    ret = krb5_kt_ret_keyblock (context, d, cursor->sp, &entry->keyblock);
    if (ret)
        goto out;
    /* there might be a 32 bit kvno here
     * if it's zero, assume that the 8bit one was right,
     * otherwise trust the new value */
    curpos = krb5_storage_seek(cursor->sp, 0, SEEK_CUR);
    if(len + 4 + pos - curpos >= 4) {
        ret = krb5_ret_int32(cursor->sp, &tmp32);
        if (ret == 0 && tmp32 != 0)
            entry->vno = tmp32;
    }
    /* there might be a flags field here */
    if(len + 4 + pos - curpos >= 8) {
        ret = krb5_ret_uint32(cursor->sp, &utmp32);
        if (ret == 0)
            entry->flags = utmp32;
    } else
        entry->flags = 0;

    entry->aliases = NULL;

    if(start) *start = pos;
    if(end) *end = pos + 4 + len;
 out:
    krb5_storage_seek(cursor->sp, pos + 4 + len, SEEK_SET);
    return ret;
}

static krb5_error_code KRB5_CALLCONV
fkt_next_entry(krb5_context context,
               krb5_keytab id,
               krb5_keytab_entry *entry,
               krb5_kt_cursor *cursor)
{
    return fkt_next_entry_int(context, id, entry, cursor, NULL, NULL);
}

static krb5_error_code KRB5_CALLCONV
fkt_end_seq_get(krb5_context context,
                krb5_keytab id,
                krb5_kt_cursor *cursor)
{
    krb5_storage_free(cursor->sp);
    _krb5_xunlock(context, cursor->fd);
    close(cursor->fd);
    return 0;
}

static krb5_error_code KRB5_CALLCONV
fkt_setup_keytab(krb5_context context,
                 krb5_keytab id,
                 krb5_storage *sp)
{
    krb5_error_code ret;
    ret = krb5_store_int8(sp, 5);
    if(ret)
        return ret;
    if(id->version == 0)
        id->version = KRB5_KT_VNO;
    return krb5_store_int8 (sp, id->version);
}

static krb5_error_code KRB5_CALLCONV
fkt_add_entry(krb5_context context,
              krb5_keytab id,
              krb5_keytab_entry *entry)
{
    int ret;
    int fd;
    krb5_storage *sp;
    struct fkt_data *d = id->data;
    krb5_data keytab;
    int32_t len;

    fd = open (d->filename, O_RDWR | O_BINARY | O_CLOEXEC);
    if (fd < 0) {
        fd = open (d->filename, O_RDWR | O_CREAT | O_EXCL | O_BINARY | O_CLOEXEC, 0600);
        if (fd < 0) {
            ret = errno;
            krb5_set_error_message(context, ret,
                                   N_("open(%s): %s", ""), d->filename,
                                   strerror(ret));
            return ret;
        }
        rk_cloexec(fd);

        ret = _krb5_xlock(context, fd, 1, d->filename);
        if (ret) {
            close(fd);
            return ret;
        }
        sp = krb5_storage_from_fd(fd);
        krb5_storage_set_eof_code(sp, KRB5_KT_END);
        ret = fkt_setup_keytab(context, id, sp);
        if(ret) {
            goto out;
        }
        storage_set_flags(context, sp, id->version);
    } else {
        int8_t pvno, tag;

        rk_cloexec(fd);

        ret = _krb5_xlock(context, fd, 1, d->filename);
        if (ret) {
            close(fd);
            return ret;
        }
        sp = krb5_storage_from_fd(fd);
        krb5_storage_set_eof_code(sp, KRB5_KT_END);
        ret = krb5_ret_int8(sp, &pvno);
        if(ret) {
            /* we probably have a zero byte file, so try to set it up
               properly */
            ret = fkt_setup_keytab(context, id, sp);
            if(ret) {
                krb5_set_error_message(context, ret,
                                       N_("%s: keytab is corrupted: %s", ""),
                                       d->filename, strerror(ret));
                goto out;
            }
            storage_set_flags(context, sp, id->version);
        } else {
            if(pvno != 5) {
                ret = KRB5_KEYTAB_BADVNO;
                krb5_set_error_message(context, ret,
                                       N_("Bad version in keytab %s", ""),
                                       d->filename);
                goto out;
            }
            ret = krb5_ret_int8 (sp, &tag);
            if (ret) {
                krb5_set_error_message(context, ret,
                                       N_("failed reading tag from "
                                          "keytab %s", ""),
                                       d->filename);
                goto out;
            }
            id->version = tag;
            storage_set_flags(context, sp, id->version);
        }
    }

    {
        krb5_storage *emem;
        emem = krb5_storage_emem();
        if(emem == NULL) {
            ret = ENOMEM;
            krb5_set_error_message(context, ret,
                                   N_("malloc: out of memory", ""));
            goto out;
        }
        ret = krb5_kt_store_principal(context, emem, entry->principal);
        if(ret) {
            krb5_set_error_message(context, ret,
                                   N_("Failed storing principal "
                                      "in keytab %s", ""),
                                   d->filename);
            krb5_storage_free(emem);
            goto out;
        }
        ret = krb5_store_int32 (emem, entry->timestamp);
        if(ret) {
            krb5_set_error_message(context, ret,
                                   N_("Failed storing timpstamp "
                                      "in keytab %s", ""),
                                   d->filename);
            krb5_storage_free(emem);
            goto out;
        }
        ret = krb5_store_int8 (emem, entry->vno % 256);
        if(ret) {
            krb5_set_error_message(context, ret,
                                   N_("Failed storing kvno "
                                      "in keytab %s", ""),
                                   d->filename);
            krb5_storage_free(emem);
            goto out;
        }
        ret = krb5_kt_store_keyblock (context, d, emem, &entry->keyblock);
        if(ret) {
            krb5_storage_free(emem);
            goto out;
        }
        if ((d->flags & KRB5_KT_FL_JAVA) == 0) {
            ret = krb5_store_int32 (emem, entry->vno);
            if (ret) {
                krb5_set_error_message(context, ret,
                                       N_("Failed storing extended kvno "
                                          "in keytab %s", ""),
                                       d->filename);
                krb5_storage_free(emem);
                goto out;
            }
            ret = krb5_store_uint32 (emem, entry->flags);
            if (ret) {
                krb5_set_error_message(context, ret,
                                       N_("Failed storing extended kvno "
                                          "in keytab %s", ""),
                                       d->filename);
                krb5_storage_free(emem);
                goto out;
            }
        }

        ret = krb5_storage_to_data(emem, &keytab);
        krb5_storage_free(emem);
        if(ret) {
            krb5_set_error_message(context, ret,
                                   N_("Failed converting keytab entry "
                                      "to memory block for keytab %s", ""),
                                   d->filename);
            goto out;
        }
    }

    while(1) {
        ret = krb5_ret_int32(sp, &len);
        if(ret == KRB5_KT_END) {
            len = keytab.length;
            break;
        }
        if(len < 0) {
            len = -len;
            if(len >= (int)keytab.length) {
                krb5_storage_seek(sp, -4, SEEK_CUR);
                break;
            }
        }
        krb5_storage_seek(sp, len, SEEK_CUR);
    }
    ret = krb5_store_int32(sp, len);
    if(krb5_storage_write(sp, keytab.data, keytab.length) < 0) {
        ret = errno;
        krb5_set_error_message(context, ret,
                               N_("Failed writing keytab block "
                                  "in keytab %s: %s", ""),
                               d->filename, strerror(ret));
    }
    memset(keytab.data, 0, keytab.length);
    krb5_data_free(&keytab);
  out:
    krb5_storage_free(sp);
    _krb5_xunlock(context, fd);
    close(fd);
    return ret;
}

static krb5_error_code KRB5_CALLCONV
fkt_remove_entry(krb5_context context,
                 krb5_keytab id,
                 krb5_keytab_entry *entry)
{
    krb5_keytab_entry e;
    krb5_kt_cursor cursor;
    off_t pos_start, pos_end;
    int found = 0;
    krb5_error_code ret;

    ret = fkt_start_seq_get_int(context, id, O_RDWR | O_BINARY | O_CLOEXEC, 1, &cursor);
    if(ret != 0)
        goto out; /* return other error here? */
    while(fkt_next_entry_int(context, id, &e, &cursor,
                             &pos_start, &pos_end) == 0) {
        if(krb5_kt_compare(context, &e, entry->principal,
                           entry->vno, entry->keyblock.keytype)) {
            int32_t len;
            unsigned char buf[128];
            found = 1;
            krb5_storage_seek(cursor.sp, pos_start, SEEK_SET);
            len = pos_end - pos_start - 4;
            krb5_store_int32(cursor.sp, -len);
            memset(buf, 0, sizeof(buf));
            while(len > 0) {
                krb5_storage_write(cursor.sp, buf,
                    min((size_t)len, sizeof(buf)));
                len -= min((size_t)len, sizeof(buf));
            }
        }
        krb5_kt_free_entry(context, &e);
    }
    krb5_kt_end_seq_get(context, id, &cursor);
  out:
    if (!found) {
        krb5_clear_error_message (context);
        return KRB5_KT_NOTFOUND;
    }
    return 0;
}

const krb5_kt_ops krb5_fkt_ops = {
    "FILE",
    fkt_resolve,
    fkt_get_name,
    fkt_close,
    fkt_destroy,
    NULL, /* get */
    fkt_start_seq_get,
    fkt_next_entry,
    fkt_end_seq_get,
    fkt_add_entry,
    fkt_remove_entry
};

const krb5_kt_ops krb5_wrfkt_ops = {
    "WRFILE",
    fkt_resolve,
    fkt_get_name,
    fkt_close,
    fkt_destroy,
    NULL, /* get */
    fkt_start_seq_get,
    fkt_next_entry,
    fkt_end_seq_get,
    fkt_add_entry,
    fkt_remove_entry
};

const krb5_kt_ops krb5_javakt_ops = {
    "JAVA14",
    fkt_resolve_java14,
    fkt_get_name,
    fkt_close,
    fkt_destroy,
    NULL, /* get */
    fkt_start_seq_get,
    fkt_next_entry,
    fkt_end_seq_get,
    fkt_add_entry,
    fkt_remove_entry
};