/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */

/* lib/krb5/krb/unparse.c */

/*

 * Copyright 1990, 2008 by the Massachusetts Institute of Technology.

 * All Rights Reserved.

 *

 * Export of this software from the United States of America may

 *   require a specific license from the United States Government.

 *   It is the responsibility of any person or organization contemplating

 *   export to obtain such a license before exporting.

 *

 * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and

 * distribute this software and its documentation for any purpose and

 * without fee is hereby granted, provided that the above copyright

 * notice appear in all copies and that both that copyright notice and

 * this permission notice appear in supporting documentation, and that

 * the name of M.I.T. not be used in advertising or publicity pertaining

 * to distribution of the software without specific, written prior

 * permission.  Furthermore if you modify this software you must label

 * your software as modified software and not distribute it in such a

 * fashion that it might be confused with the original M.I.T. software.

 * M.I.T. makes no representations about the suitability of

 * this software for any purpose.  It is provided "as is" without express

 * or implied warranty.

 */

/*

 * krb5_unparse_name() routine

 *

 * Rewritten by Theodore Ts'o to properly unparse principal names

 * which have the component or realm separator as part of one of their

 * components.

 */

#include "k5-int.h"

#include <stdio.h>

/*

 * converts the multi-part principal format used in the protocols to a

 * single-string representation of the name.

 *

 * The name returned is in allocated storage and should be freed by

 * the caller when finished.

 *

 * Conventions: / is used to separate components; @ is used to

 * separate the realm from the rest of the name.  If '/', '@', or '\0'

 * appear in any the component, they will be representing using

 * backslash encoding.  ("\/", "\@", or '\0', respectively)

 *

 * returns error

 *      KRB_PARSE_MALFORMED     principal is invalid (does not contain

 *                              at least 2 components)

 * also returns system errors

 *      ENOMEM                  unable to allocate memory for string

 */

#define REALM_SEP       '@'

#define COMPONENT_SEP   '/'

static int

component_length_quoted(const krb5_data *src, int flags)

{

    const char *cp = src->data;

    int length = src->length;

    int j;

    int size = length;

    if ((flags & KRB5_PRINCIPAL_UNPARSE_DISPLAY) == 0) {

        int no_realm = (flags & KRB5_PRINCIPAL_UNPARSE_NO_REALM) &&

            !(flags & KRB5_PRINCIPAL_UNPARSE_SHORT);

        for (j = 0; j < length; j++,cp++)

            if ((!no_realm && *cp == REALM_SEP) ||

                *cp == COMPONENT_SEP ||

                *cp == '\0' || *cp == '\\' || *cp == '\t' ||

                *cp == '\n' || *cp == '\b')

                size++;

    }

    return size;

}

static int

copy_component_quoting(char *dest, const krb5_data *src, int flags)

{

    int j;

    const char *cp = src->data;

    char *q = dest;

    int length = src->length;

    if (flags & KRB5_PRINCIPAL_UNPARSE_DISPLAY) {

        if (src->length > 0)

            memcpy(dest, src->data, src->length);

        return src->length;

    }

    for (j=0; j < length; j++,cp++) {

        int no_realm = (flags & KRB5_PRINCIPAL_UNPARSE_NO_REALM) &&

            !(flags & KRB5_PRINCIPAL_UNPARSE_SHORT);

        switch (*cp) {

        case REALM_SEP:

            if (no_realm) {

                *q++ = *cp;

                break;

            }

        case COMPONENT_SEP:

        case '\\':

            *q++ = '\\';

            *q++ = *cp;

            break;

        case '\t':

            *q++ = '\\';

            *q++ = 't';

            break;

        case '\n':

            *q++ = '\\';

            *q++ = 'n';

            break;

        case '\b':

            *q++ = '\\';

            *q++ = 'b';

            break;

        case '\0':

            *q++ = '\\';

            *q++ = '0';

            break;

        default:

            *q++ = *cp;

        }

    }

    return q - dest;

}

static krb5_error_code

k5_unparse_name(krb5_context context, krb5_const_principal principal,

                int flags, char **name, unsigned int *size)

{

    char *q;

    krb5_int32 i;

    unsigned int totalsize = 0;

    char *default_realm = NULL;

    krb5_error_code ret = 0;

    if (!principal || !name)

        return KRB5_PARSE_MALFORMED;

    if (flags & KRB5_PRINCIPAL_UNPARSE_SHORT) {

        /* omit realm if local realm */

        krb5_principal_data p;

        ret = krb5_get_default_realm(context, &default_realm);

        if (ret != 0)

            goto cleanup;

        p.realm = string2data(default_realm);

        if (krb5_realm_compare(context, &p, principal))

            flags |= KRB5_PRINCIPAL_UNPARSE_NO_REALM;

    }

    if ((flags & KRB5_PRINCIPAL_UNPARSE_NO_REALM) == 0) {

        totalsize += component_length_quoted(&principal->realm, flags);

        totalsize++;            /* This is for the separator */

    }

    for (i = 0; i < principal->length; i++) {

        totalsize += component_length_quoted(&principal->data[i], flags);

        totalsize++;    /* This is for the separator */

    }

    if (principal->length == 0)

        totalsize++;

    /*

     * Allocate space for the ascii string; if space has been

     * provided, use it, realloc'ing it if necessary.

     *

     * We need only n-1 separators for n components, but we need

     * an extra byte for the NUL at the end.

     */

    if (size) {

        if (*name && (*size < totalsize)) {

            *name = realloc(*name, totalsize);

        } else {

            *name = malloc(totalsize);

        }

        *size = totalsize;

    } else {

        *name = malloc(totalsize);

    }

    if (!*name) {

        ret = ENOMEM;

        goto cleanup;

    }

    q = *name;

    for (i = 0; i < principal->length; i++) {

        q += copy_component_quoting(q, &principal->data[i], flags);

        *q++ = COMPONENT_SEP;

    }

    if (i > 0)

        q--;                /* Back up last component separator */

    if ((flags & KRB5_PRINCIPAL_UNPARSE_NO_REALM) == 0) {

        *q++ = REALM_SEP;

        q += copy_component_quoting(q, &principal->realm, flags);

    }

    *q++ = '\0';

cleanup:

    if (default_realm != NULL)

        krb5_free_default_realm(context, default_realm);

    return ret;

}

krb5_error_code KRB5_CALLCONV

krb5_unparse_name(krb5_context context, krb5_const_principal principal,

                  char **name)

{

    if (name != NULL)                      /* name == NULL will return error from _ext */

        *name = NULL;

    return k5_unparse_name(context, principal, 0, name, NULL);

}

krb5_error_code KRB5_CALLCONV

krb5_unparse_name_ext(krb5_context context, krb5_const_principal principal,

                      char **name, unsigned int *size)

{

    return k5_unparse_name(context, principal, 0, name, size);

}

krb5_error_code KRB5_CALLCONV

krb5_unparse_name_flags(krb5_context context, krb5_const_principal principal,

                        int flags, char **name)

{

    if (name != NULL)

        *name = NULL;

    return k5_unparse_name(context, principal, flags, name, NULL);

}

krb5_error_code KRB5_CALLCONV

krb5_unparse_name_flags_ext(krb5_context context, krb5_const_principal principal,

                            int flags, char **name, unsigned int *size)

{

    return k5_unparse_name(context, principal, flags, name, size);

}