xlat_tokenize.c

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/*
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA
 */
 
/**
 * $Id: f35029b4b1fcd60ee5db6eda0178bba8c68bf3a7 $
 *
 * @file xlat_tokenize.c
 * @brief String expansion ("translation").  Tokenizes xlat expansion strings.
 *
 * @copyright 2017-2021 Arran Cudbard-Bell (a.cudbardb@freeradius.org)
 * @copyright 2000 Alan DeKok (aland@freeradius.org)
 * @copyright 2000,2006 The FreeRADIUS server project
 */
 
#include "lib/util/event.h"
#include "lib/util/value.h"
RCSID("$Id: f35029b4b1fcd60ee5db6eda0178bba8c68bf3a7 $")
 
#include <freeradius-devel/util/debug.h>
#include <freeradius-devel/util/sbuff.h>
#include <freeradius-devel/server/regex.h>
#include <freeradius-devel/unlang/xlat_priv.h>
 
#undef XLAT_DEBUG
#undef XLAT_HEXDUMP
#ifdef DEBUG_XLAT
#  define XLAT_DEBUG(_fmt, ...)                 DEBUG3("%s[%i] "_fmt, __FILE__, __LINE__, ##__VA_ARGS__)
#  define XLAT_HEXDUMP(_data, _len, _fmt, ...)  HEXDUMP3(_data, _len, "%s[%i] "_fmt, __FILE__, __LINE__, ##__VA_ARGS__)
#else
#  define XLAT_DEBUG(...)
#  define XLAT_HEXDUMP(...)
#endif
 
/** These rules apply to literal values and function arguments inside of an expansion
 *
 */
static fr_sbuff_unescape_rules_t const xlat_unescape = {
        .name = "xlat",
        .chr = '\\',
        .subs = {
                ['a'] = '\a',
                ['b'] = '\b',
                ['e'] = '\\',
                ['n'] = '\n',
                ['r'] = '\r',
                ['t'] = '\t',
                ['v'] = '\v',
                ['\\'] = '\\',
                ['%'] = '%',    /* Expansion begin */
                ['}'] = '}'     /* Expansion end */
        },
        .do_hex = true,
        .do_oct = true
};
 
/** These rules apply to literal values and function arguments inside of an expansion
 *
 */
static fr_sbuff_escape_rules_t const xlat_escape = {
        .name = "xlat",
        .chr = '\\',
        .subs = {
                ['\a'] = 'a',
                ['\b'] = 'b',
                ['\n'] = 'n',
                ['\r'] = 'r',
                ['\t'] = 't',
                ['\v'] = 'v',
                ['\\'] = '\\',
                ['%'] = '%',    /* Expansion begin */
                ['}'] = '}'     /* Expansion end */
        },
        .esc = {
                SBUFF_CHAR_UNPRINTABLES_LOW,
                SBUFF_CHAR_UNPRINTABLES_EXTENDED
        },
        .do_utf8 = true,
        .do_oct = true
};
 
/** Parse rules for literal values inside of an expansion
 *
 * These rules are used to parse literals as arguments to functions and
 * on the RHS of alternations.
 *
 * The caller sets the literal parse rules for outside of expansions when they
 * call xlat_tokenize.
 */
static fr_sbuff_parse_rules_t const xlat_function_arg_rules = {
        .escapes = &xlat_unescape,
        .terminals = &FR_SBUFF_TERMS( /* These get merged with other literal terminals */
                                L(")"),
                                L(","),
                ),
};
 
static int xlat_tokenize_input(xlat_exp_head_t *head, fr_sbuff_t *in,
                                fr_sbuff_parse_rules_t const *p_rules, tmpl_rules_t const *t_rules, fr_value_box_safe_for_t safe_for);
 
#ifdef HAVE_REGEX
/** Parse an xlat reference
 *
 * Allows access to a subcapture groups
 * @verbatim %{<num>} @endverbatim
 *
 */
static inline int xlat_tokenize_regex(xlat_exp_head_t *head, fr_sbuff_t *in)
{
        uint8_t                 num;
        xlat_exp_t              *node;
        fr_sbuff_parse_error_t  err;
        fr_sbuff_marker_t       m_s;
 
        XLAT_DEBUG("REGEX <-- %.*s", (int) fr_sbuff_remaining(in), fr_sbuff_current(in));
 
        fr_sbuff_marker(&m_s, in);
 
        (void) fr_sbuff_out(&err, &num, in);
        if (err != FR_SBUFF_PARSE_OK) {
        invalid_ref:
                fr_strerror_printf("Invalid regex reference.  Must be in range 0-%u", REQUEST_MAX_REGEX);
                fr_sbuff_marker_release(&m_s);
                return -1;
        }
 
        if (num > REQUEST_MAX_REGEX) {
                fr_sbuff_set(in, &m_s);
                goto invalid_ref;
        }
 
        if (!fr_sbuff_is_char(in, '}')) {
                if (!fr_sbuff_remaining(in)) {
                        fr_strerror_const("Missing closing brace");
                        fr_sbuff_marker_release(&m_s);
                        return -1;
                }
                fr_sbuff_set(in, &m_s);
                fr_sbuff_marker_release(&m_s);
                return 1;
        }
 
        node = xlat_exp_alloc(head, XLAT_REGEX, fr_sbuff_current(&m_s), fr_sbuff_behind(&m_s));
        node->regex_index = num;
 
        fr_sbuff_marker_release(&m_s);
        fr_sbuff_next(in);      /* Skip '}' */
 
        xlat_exp_insert_tail(head, node);
 
        return 0;
}
#endif
 
int xlat_validate_function_mono(xlat_exp_t *node)
{
        fr_assert(node->type == XLAT_FUNC);
 
        if (node->call.func->args && node->call.func->args->required && !xlat_exp_head(node->call.args)) {
                fr_strerror_const("Missing required input");
                return -1;
        }
 
        return 0;
}
 
bool const xlat_func_chars[UINT8_MAX + 1] = {
        SBUFF_CHAR_CLASS_ALPHA_NUM,
        ['.'] = true, ['-'] = true, ['_'] = true,
};
 
 
static int xlat_validate_function_arg(xlat_arg_parser_t const *arg_p, xlat_exp_t *arg)
{
        ssize_t slen;
        xlat_exp_t *node;
        fr_value_box_t box;
 
        /*
         *      The caller doesn't care about the type, OR the type is string, which it already is.
         */
        if ((arg_p->type == FR_TYPE_VOID) || (arg_p->type == FR_TYPE_STRING)) {
                return 0;
        }
 
        node = xlat_exp_head(arg->group);
 
        if (!node) return -1;
 
        /*
         *      @todo - check arg_p->single, and complain.
         */
        if (xlat_exp_next(arg->group, node)) return 0;
 
        /*
         *      @todo - These checks are relatively basic.  We should do better checks, such as if the
         *      expected type is not string/octets, and the passed arguments are multiple things, then
         *      die?
         *
         *      And check also the 'concat' flag?
         */
        if (node->type != XLAT_BOX) return 0;
 
        /*
         *      Boxes are always strings, because of xlat_tokenize_input()
         */
        fr_assert(node->data.type == FR_TYPE_STRING);
 
        fr_value_box_init_null(&box);
 
        /*
         *      The entire string must be parseable as the data type we expect.
         */
        slen = fr_value_box_from_str(node, &box, arg_p->type, NULL, /* no enum */
                                     node->data.vb_strvalue, node->data.vb_length,
                                     NULL, /* no parse rules */
                                     node->data.tainted);
        if (slen <= 0) return -1;
 
        /*
         *      Replace the string value with the parsed data type.
         */
        fr_value_box_clear(&node->data);
        fr_value_box_copy(node, &node->data, &box);
 
        return 0;
}
 
int xlat_validate_function_args(xlat_exp_t *node)
{
        xlat_arg_parser_t const *arg_p;
        xlat_exp_t              *arg = xlat_exp_head(node->call.args);
        int                     i = 0;
 
        fr_assert(node->type == XLAT_FUNC);
 
        for (arg_p = node->call.func->args, i = 0; arg_p->type != FR_TYPE_NULL; arg_p++) {
                if (!arg_p->required) break;
 
                if (!arg) {
                        fr_strerror_printf("Missing required arg %u",
                                           (unsigned int)(arg_p - node->call.func->args) + 1);
                        return -1;
                }
 
                /*
                 *      All arguments MUST be put into a group, even
                 *      if they're just one element.
                 */
                fr_assert(arg->type == XLAT_GROUP);
 
                if (xlat_validate_function_arg(arg_p, arg) < 0) {
                        fr_strerror_printf("Failed parsing argument %d as type '%s'", i, fr_type_to_str(arg_p->type));
                        return -1;
                }
 
                arg = xlat_exp_next(node->call.args, arg);
                i++;
        }
 
        return 0;
}
 
/** Parse an xlat function and its child argument
 *
 * Parses a function call string in the format
 * @verbatim %<func>(<argument>) @endverbatim
 *
 * @return
 *      - 0 if the string was parsed into a function.
 *      - <0 on parse error.
 */
static int xlat_tokenize_function_args(xlat_exp_head_t *head, fr_sbuff_t *in, tmpl_rules_t const *t_rules)
{
        char c;
        xlat_exp_t *node;
        xlat_t *func;
        fr_sbuff_marker_t m_s;
 
        fr_sbuff_marker(&m_s, in);
 
        XLAT_DEBUG("NEW <-- %pV", fr_box_strvalue_len(fr_sbuff_current(in), fr_sbuff_remaining(in)));
 
        /*
         *      The caller ensures that the first character aftet the percent exists, and is alphanumeric.
         */
        c = fr_sbuff_char(in, '\0');
 
        /*
         *      Even if it is alphanumeric, only a limited set of characters are one-letter expansions.
         *
         *      And even then only if the character after them is a terminal character.
         */
        if (strchr("cCdDeGHIlmMnSstTY", c) != NULL) {
                char n;
 
                fr_sbuff_next(in);
 
                /*
                 *      End of buffer == one letter expansion.
                 */
                n = fr_sbuff_char(in, '\0');
                if (!n) goto one_letter;
 
                /*
                 *      %Y() is the new format.
                 */
                if (n == '(') {
                        fr_sbuff_next(in);
 
                        if (!fr_sbuff_next_if_char(in, ')')) {
                                fr_strerror_const("Missing ')'");
                                return -1;
                        }
 
                        goto one_letter;
                }
 
                /*
                 *      %M. or %Y- is a one-letter expansion followed by the other character.
                 */
                if (!sbuff_char_alpha_num[(unsigned int) n]) {
                one_letter:
                        XLAT_DEBUG("ONE-LETTER <-- %c", c);
                        node = xlat_exp_alloc_null(head);
 
                        xlat_exp_set_type(node, XLAT_ONE_LETTER);
                        xlat_exp_set_name(node, fr_sbuff_current(&m_s), 1);
 
                        fr_sbuff_marker_release(&m_s);
 
#ifdef STATIC_ANALYZER
                        if (!node->fmt) return -1;
#endif
 
                        /*
                         *      %% is pure.  Everything else is not.
                         */
                        node->flags.pure = (node->fmt[0] == '%');
 
                        xlat_exp_insert_tail(head, node);
                        return 0;
                }
 
                /*
                 *      Anything else, it must be a full function name.
                 */
                fr_sbuff_set(in, &m_s);
        }
 
        fr_sbuff_adv_past_allowed(in, SIZE_MAX, xlat_func_chars, NULL);
 
        func = xlat_func_find(fr_sbuff_current(&m_s), fr_sbuff_behind(&m_s));
 
        if (!fr_sbuff_is_char(in, '(')) {
                fr_strerror_printf("Missing '('");
                return -1;
        }
 
        /*
         *      Allocate a node to hold the function
         */
        node = xlat_exp_alloc(head, XLAT_FUNC, fr_sbuff_current(&m_s), fr_sbuff_behind(&m_s));
        if (!func) {
                if (!t_rules || !t_rules->attr.allow_unresolved|| t_rules->at_runtime) {
                        fr_strerror_const("Unresolved expansion functions are not allowed here");
                        fr_sbuff_set(in, &m_s);         /* backtrack */
                        fr_sbuff_marker_release(&m_s);
                        return -1;
                }
                xlat_exp_set_type(node, XLAT_FUNC_UNRESOLVED);
                node->flags.needs_resolving = true;     /* Needs resolution during pass2 */
        } else {
                node->call.func = func;
                if (t_rules) node->call.dict = t_rules->attr.dict_def;
                node->flags = func->flags;
                node->call.input_type = func->input_type;
        }
 
        (void) fr_sbuff_next(in); /* skip the '(' */
 
        /*
         *      Now parse the child nodes that form the
         *      function's arguments.
         */
        if (xlat_tokenize_argv(node, &node->call.args, in, func,
                               &xlat_function_arg_rules, t_rules, true, (node->call.input_type == XLAT_INPUT_MONO)) < 0) {
error:
                talloc_free(node);
                return -1;
        }
 
        xlat_flags_merge(&node->flags, &node->call.args->flags);
 
        if (!fr_sbuff_next_if_char(in, ')')) {
                fr_strerror_const("Missing closing brace");
                goto error;
        }
 
        /*
         *      Validate the arguments.
         */
        if (node->type == XLAT_FUNC) {
                switch (node->call.input_type) {
                case XLAT_INPUT_UNPROCESSED:
                        break;
 
                case XLAT_INPUT_MONO:
                        if (xlat_validate_function_mono(node) < 0) goto error;
                        node->flags.can_purify = (node->call.func->flags.pure && node->call.args->flags.pure) | node->call.args->flags.can_purify;
                        break;
 
                case XLAT_INPUT_ARGS:
                        if (xlat_validate_function_args(node) < 0) goto error;
                        node->flags.can_purify = (node->call.func->flags.pure && node->call.args->flags.pure) | node->call.args->flags.can_purify;
                        break;
                }
        }
 
        xlat_exp_insert_tail(head, node);
        return 0;
}
 
static int xlat_resolve_virtual_attribute(xlat_exp_t *node, tmpl_t *vpt)
{
        xlat_t  *func;
 
        if (tmpl_is_attr(vpt)) {
                func = xlat_func_find(tmpl_attr_tail_da(vpt)->name, -1);
        } else {
                func = xlat_func_find(tmpl_attr_tail_unresolved(vpt), -1);
        }
        if (!func) return -1;
 
        xlat_exp_set_type(node, XLAT_VIRTUAL);
        xlat_exp_set_name_buffer_shallow(node, vpt->name);
 
        XLAT_DEBUG("VIRTUAL <-- %pV",
                   fr_box_strvalue_len(vpt->name, vpt->len));
        node->call.func = func;
        node->flags = func->flags;
 
        return 0;
}
 
/** Parse an attribute ref or a virtual attribute
 *
 */
static int xlat_tokenize_attribute(xlat_exp_head_t *head, fr_sbuff_t *in,
                                   fr_sbuff_parse_rules_t const *p_rules, tmpl_rules_t const *t_rules, tmpl_attr_prefix_t attr_prefix)
{
        tmpl_attr_error_t       err;
        tmpl_t                  *vpt = NULL;
        xlat_exp_t              *node;
 
        fr_sbuff_marker_t       m_s;
        tmpl_rules_t             our_t_rules;
 
        XLAT_DEBUG("ATTRIBUTE <-- %.*s", (int) fr_sbuff_remaining(in), fr_sbuff_current(in));
 
        /*
         *      We need a local copy as we always allow unknowns.
         *      This is because not all attribute references
         *      reference real attributes in the dictionaries,
         *      and instead are "virtual" attributes like
         *      Foreach-Variable-N.
         */
        if (t_rules) {
                memset(&our_t_rules, 0, sizeof(our_t_rules));
                our_t_rules = *t_rules;
        } else {
                memset(&our_t_rules, 0, sizeof(our_t_rules));
        }
 
        our_t_rules.attr.allow_unresolved = true;               /* So we can check for virtual attributes later */
        our_t_rules.attr.prefix = attr_prefix;                  /* Must be NO to stop %{&User-Name} */
 
        fr_sbuff_marker(&m_s, in);
 
        MEM(node = xlat_exp_alloc_null(head));
        if (tmpl_afrom_attr_substr(node, &err, &vpt, in, p_rules, &our_t_rules) < 0) {
                /*
                 *      If the parse error occurred before a terminator,
                 *      then the error is changed to 'Unknown module',
                 *      as it was more likely to be a bad module name,
                 *      than a request qualifier.
                 */
                if (err == TMPL_ATTR_ERROR_MISSING_TERMINATOR) fr_sbuff_set(in, &m_s);
        error:
                fr_sbuff_marker_release(&m_s);
                talloc_free(node);
                FR_SBUFF_ERROR_RETURN(in);
        }
 
        /*
         *      Deal with unresolved attributes.
         */
        if (tmpl_is_attr_unresolved(vpt)) {
                /*
                 *      Could it be a virtual attribute?
                 */
                if ((tmpl_attr_num_elements(vpt) == 2) && (xlat_resolve_virtual_attribute(node, vpt) == 0)) goto done;
 
                if (!t_rules || !t_rules->attr.allow_unresolved) {
                        talloc_free(vpt);
 
                        fr_strerror_const("Unresolved attributes not allowed in expansions here");
                        fr_sbuff_set(in, &m_s);         /* Error at the start of the attribute */
                        goto error;
                }
 
                /*
                 *      We don't know it's virtual but
                 *      we don't know it's not either...
                 *
                 *      Mark it up as virtual-unresolved
                 *      and let the resolution code figure
                 *      this out in a later pass.
                 */
                xlat_exp_set_type(node, XLAT_VIRTUAL_UNRESOLVED);
                xlat_exp_set_name_buffer_shallow(node, vpt->name);
                node->vpt = vpt;
                node->flags.needs_resolving = true;
        /*
         *      Deal with normal attribute (or list)
         */
        } else {
                xlat_exp_set_type(node, XLAT_TMPL);
                xlat_exp_set_name_buffer_shallow(node, vpt->name);
                node->vpt = vpt;
        }
 
done:
        /*
         *      Attributes and module calls aren't pure.
         */
        node->flags.pure = false;
 
        xlat_exp_insert_tail(head, node);
 
        fr_sbuff_marker_release(&m_s);
        return 0;
}
 
static bool const tmpl_attr_allowed_chars[UINT8_MAX + 1] = {
        SBUFF_CHAR_CLASS_ALPHA_NUM,
        ['-'] = true, ['/'] = true, ['_'] = true,                       // fr_dict_attr_allowed_chars
        ['.'] = true, ['*'] = true, ['#'] = true,
        ['['] = true, [']'] = true,                                     // tmpls and attribute arrays
};
 
int xlat_tokenize_expansion(xlat_exp_head_t *head, fr_sbuff_t *in,
                            tmpl_rules_t const *t_rules)
{
        size_t                  len;
        fr_sbuff_marker_t       s_m;
        char                    hint;
        fr_sbuff_term_t         hint_tokens = FR_SBUFF_TERMS(
                                        L(" "),         /* First special token is a ' ' - Likely a syntax error */
                                        L("["),         /* First special token is a '[' i.e. '%{attr[<idx>]}' */
                                        L("}")          /* First special token is a '}' i.e. '%{<attrref>}' */
                                );
 
        fr_sbuff_parse_rules_t  attr_p_rules = {
                                        .escapes = &xlat_unescape,
                                        .terminals = &FR_SBUFF_TERM("}")
                                };
 
        XLAT_DEBUG("EXPANSION <-- %.*s", (int) fr_sbuff_remaining(in), fr_sbuff_current(in));
 
#ifdef HAVE_REGEX
        fr_sbuff_marker(&s_m, in);
        len = fr_sbuff_adv_past_allowed(in, SIZE_MAX, sbuff_char_class_uint, NULL);
 
        /*
         *      Handle regex's %{<num>} specially.  But '3GPP-Foo' is an attribute.  :(
         */
        if (len && fr_sbuff_is_char(in, '}')) {
                int ret;
 
                fr_sbuff_set(in, &s_m);         /* backtrack */
                ret = xlat_tokenize_regex(head, in);
                if (ret <= 0) return ret;
 
                /* ret==1 means "nope, it's an attribute" */
        }
        fr_sbuff_set(in, &s_m);         /* backtrack */
 
#endif /* HAVE_REGEX */
 
        /*
         *      See if it's an attribute reference, with possible array stuff.
         */
        len = fr_sbuff_adv_past_allowed(in, SIZE_MAX, tmpl_attr_allowed_chars, NULL);
        if (fr_sbuff_is_char(in, '}')) {
                if (!len) goto empty_disallowed;
                goto check_for_attr;
        }
 
        if (!fr_sbuff_extend(in)) {
                fr_strerror_const("Missing closing brace");
                fr_sbuff_marker_release(&s_m);
                return -1;
        }
 
        /*
         *      It must be an expression.
         *
         *      We wrap the xlat in a tmpl, so that the result is just a value, and not wrapped in another
         *      XLAT_GROUP, which turns into a wrapper of FR_TYPE_GROUP in the value-box.
         */
        {
                int ret;
                char *fmt;
                xlat_exp_t *node;
                xlat_exp_head_t *child;
                tmpl_rules_t my_rules;
 
                fr_sbuff_set(in, &s_m);         /* backtrack to the start of the expression */
 
                MEM(node = xlat_exp_alloc(head, XLAT_TMPL, NULL, 0));
                MEM(node->vpt = tmpl_alloc(node, TMPL_TYPE_XLAT, T_BARE_WORD, "", 1));
 
                if (t_rules) {
                        my_rules = *t_rules;
                        my_rules.enumv = NULL;
                        my_rules.cast = FR_TYPE_NULL;
                        t_rules = &my_rules;
                }
 
                ret = xlat_tokenize_expression(node->vpt, &child, in, &attr_p_rules, t_rules);
                if (ret <= 0) {
                        talloc_free(node);
                        return ret;
                }
 
                if (!fr_sbuff_is_char(in, '}')) {
                        fr_strerror_const("Missing closing brace");
                        return -1;
                }
 
                MEM(fmt = talloc_bstrndup(node, fr_sbuff_current(&s_m), fr_sbuff_behind(&s_m)));
                xlat_exp_set_name_buffer_shallow(node, fmt);
                tmpl_set_name_shallow(node->vpt, T_BARE_WORD, fmt, fr_sbuff_behind(&s_m));
 
                tmpl_set_xlat(node->vpt, child);
                xlat_exp_insert_tail(head, node);
 
                child->flags.xlat = true;
                node->flags = child->flags;
                fr_assert(tmpl_xlat(node->vpt) != NULL);
 
                (void) fr_sbuff_next(in); /* skip '}' */
                return ret;
        }
 
check_for_attr:
        fr_sbuff_set(in, &s_m);         /* backtrack */
 
        /*
         *      %{Attr-Name}
         *      %{Attr-Name[#]}
         *      %{request.Attr-Name}
         */
 
        /*
         *      Check for empty expressions %{} %{: %{[
         */
        fr_sbuff_marker(&s_m, in);
        len = fr_sbuff_adv_until(in, SIZE_MAX, &hint_tokens, '\0');
 
        /*
         *      This means the end of a string not containing any of the other
         *      tokens was reached.
         *
         *      e.g. '%{myfirstxlat'
         */
        if (!fr_sbuff_extend(in)) {
                fr_strerror_const("Missing closing brace");
                fr_sbuff_marker_release(&s_m);
                return -1;
        }
 
        hint = fr_sbuff_char(in, '\0');
 
        XLAT_DEBUG("EXPANSION HINT TOKEN '%c'", hint);
        if (len == 0) {
                switch (hint) {
                case '}':
                empty_disallowed:
                        fr_strerror_const("Empty expression is invalid");
                        return -1;
 
                case '[':
                        fr_strerror_const("Missing attribute name");
                        return -1;
 
                default:
                        break;
                }
        }
 
        switch (hint) {
        /*
         *      Hint token is a:
         *      - '[' - Which is an attribute index, so it must be an attribute.
         *      - '}' - The end of the expansion, which means it was a bareword.
         */
        case '.':
        case '}':
        case '[':
                fr_sbuff_set(in, &s_m);         /* backtrack */
                fr_sbuff_marker_release(&s_m);
 
                if (xlat_tokenize_attribute(head, in, &attr_p_rules, t_rules, TMPL_ATTR_REF_PREFIX_NO) < 0) return -1;
 
                if (!fr_sbuff_next_if_char(in, '}')) {
                        fr_strerror_const("Missing closing brace");
                        return -1;
                }
 
                return 0;
 
        /*
         *      Hint token was whitespace
         *
         *      e.g. '%{my '
         */
        default:
                break;
        }
 
        /*
         *      Box print is so we get \t \n etc..
         */
        fr_strerror_printf("Invalid char '%pV' in expression", fr_box_strvalue_len(fr_sbuff_current(in), 1));
        return -1;
}
 
/** Parse an xlat string i.e. a non-expansion or non-function
 *
 * When this function is being used outside of an xlat expansion, i.e. on a string
 * which contains one or more xlat expansions, it uses the terminal grammar and
 * escaping rules of that string type.
 *
 * Which this function is being used inside of an xlat expansion, it uses xlat specific
 * terminal grammar and escaping rules.
 *
 * This allows us to be smart about processing quotes within the expansions themselves.
 *
 * @param[out] head             to allocate nodes in, and where to write the first
 *                              child, and where the flags are stored.
 * @param[in] in                sbuff to parse.
 * @param[in] p_rules           that control parsing.
 * @param[in] t_rules           that control attribute reference and xlat function parsing.
 * @param[in] safe_for          mark up literal values as being pre-escaped.  May be merged
 *                              with t_rules in future.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
static int xlat_tokenize_input(xlat_exp_head_t *head, fr_sbuff_t *in,
                               fr_sbuff_parse_rules_t const *p_rules, tmpl_rules_t const *t_rules,
                               fr_value_box_safe_for_t safe_for)
{
        xlat_exp_t                      *node = NULL;
        fr_slen_t                       slen;
        fr_sbuff_term_t                 terminals = FR_SBUFF_TERMS(
                                                L("%"),
                                        );
        fr_sbuff_term_t                 *tokens;
        fr_sbuff_unescape_rules_t const *escapes;
 
        XLAT_DEBUG("STRING <-- %.*s", (int) fr_sbuff_remaining(in), fr_sbuff_current(in));
 
        escapes = p_rules ? p_rules->escapes : NULL;
        tokens = p_rules && p_rules->terminals ?
                        fr_sbuff_terminals_amerge(NULL, p_rules->terminals, &terminals) : &terminals;
 
        for (;;) {
                char *str;
                fr_sbuff_marker_t m_s;
 
                /*
                 *      pre-allocate the node so we don't have to steal it later.
                 */
                node = xlat_exp_alloc(head, XLAT_BOX, NULL, 0);
 
                /*
                 *      Find the next token
                 */
                fr_sbuff_marker(&m_s, in);
                slen = fr_sbuff_out_aunescape_until(node, &str, in, SIZE_MAX, tokens, escapes);
 
                if (slen < 0) {
                error:
                        talloc_free(node);
 
                        /*
                         *      Free our temporary array of terminals
                         */
                        if (tokens != &terminals) talloc_free(tokens);
                        fr_sbuff_marker_release(&m_s);
                        return -1;
                }
 
                /*
                 *      It's a value box, create an appropriate node
                 */
                if (slen > 0) {
                do_value_box:
                        xlat_exp_set_name_buffer_shallow(node, str);
                        fr_value_box_strdup(node, &node->data, NULL, str, false);
                        fr_value_box_mark_safe_for(&node->data, safe_for);
                        node->flags.constant = true;
                        fr_assert(node->flags.pure);
 
                        if (!escapes) {
                                XLAT_DEBUG("VALUE-BOX %s <-- %.*s", str,
                                           (int) fr_sbuff_behind(&m_s), fr_sbuff_current(&m_s));
                        } else {
                                XLAT_DEBUG("VALUE-BOX (%s) %s <-- %.*s", escapes->name, str,
                                           (int) fr_sbuff_behind(&m_s), fr_sbuff_current(&m_s));
                        }
                        XLAT_HEXDUMP((uint8_t const *)str, talloc_array_length(str) - 1, " VALUE-BOX ");
 
                        xlat_exp_insert_tail(head, node);
 
                        node = NULL;
                        fr_sbuff_marker_release(&m_s);
                        continue;
                }
 
 
                /*
                 *      We have parsed as much as we can as unescaped
                 *      input.  Either some text (and added the node
                 *      to the list), or zero text.  We now try to
                 *      parse '%' expansions.
                 */
 
                /*
                 *      Attribute, function call, or other expansion.
                 */
                if (fr_sbuff_adv_past_str_literal(in, "%{")) {
                        TALLOC_FREE(node); /* nope, couldn't use it */
                        if (xlat_tokenize_expansion(head, in, t_rules) < 0) goto error;
                next:
                        fr_sbuff_marker_release(&m_s);
                        continue;
                }
 
                /*
                 *      More migration hacks: allow %foo(...)
                 */
                if (fr_sbuff_next_if_char(in, '%')) {
                        /*
                         *      % non-alphanumeric, create a value-box for just the "%" character.
                         */
                        if (!fr_sbuff_is_alnum(in)) {
                                if (fr_sbuff_next_if_char(in, '%')) { /* nothing */ }
 
                                str = talloc_typed_strdup(node, "%");
                                goto do_value_box;
                        }
 
                        TALLOC_FREE(node); /* nope, couldn't use it */
 
                        /*
                         *      Tokenize the function arguments using the new method.
                         */
                        if (xlat_tokenize_function_args(head, in, t_rules) < 0) goto error;
                        goto next;
                }
 
                /*
                 *      Nothing we recognize.  Just return nothing.
                 */
                TALLOC_FREE(node);
                XLAT_DEBUG("VALUE-BOX <-- (empty)");
                fr_sbuff_marker_release(&m_s);
                break;
        }
 
        /*
         *      Free our temporary array of terminals
         */
        if (tokens != &terminals) talloc_free(tokens);
 
        return 0;
}
 
static fr_table_num_sorted_t const xlat_quote_table[] = {
        { L("\""),      T_DOUBLE_QUOTED_STRING  },      /* Don't re-order, backslash throws off ordering */
        { L("'"),       T_SINGLE_QUOTED_STRING  },
        { L("`"),       T_BACK_QUOTED_STRING    }
};
static size_t xlat_quote_table_len = NUM_ELEMENTS(xlat_quote_table);
 
#define INFO_INDENT(_fmt, ...)  INFO("%*s"_fmt, depth * 2, " ", ## __VA_ARGS__)
 
static void _xlat_debug_head(xlat_exp_head_t const *head, int depth);
static void _xlat_debug_node(xlat_exp_t const *node, int depth)
{
        INFO_INDENT("{");
        depth++;
 
        if (node->quote != T_BARE_WORD) INFO_INDENT("quote = %c", fr_token_quote[node->quote]);
 
        switch (node->type) {
        case XLAT_BOX:
                INFO_INDENT("value %s --> %pV", fr_type_to_str(node->data.type), &node->data);
                break;
 
        case XLAT_GROUP:
                INFO_INDENT("group");
                INFO_INDENT("{");
                _xlat_debug_head(node->group, depth + 1);
                INFO_INDENT("}");
                break;
 
        case XLAT_ONE_LETTER:
                INFO_INDENT("percent (%c)", node->fmt[0]);
                break;
 
        case XLAT_TMPL:
        {
                if (tmpl_is_attr(node->vpt)) {
                        fr_assert(!node->flags.pure);
                        INFO_INDENT("attribute (%s)", tmpl_attr_tail_da(node->vpt)->name);
                        if (tmpl_attr_tail_num(node->vpt) != NUM_UNSPEC) {
                                FR_DLIST_HEAD(tmpl_request_list) const *list;
                                tmpl_request_t *rr = NULL;
 
                                INFO_INDENT("{");
 
                                /*
                                 *      Loop over the request references
                                 */
                                list = tmpl_request(node->vpt);
                                while ((rr = tmpl_request_list_next(list, rr))) {
                                        INFO_INDENT("ref  %d", rr->request);
                                }
                                INFO_INDENT("list %s", tmpl_list_name(tmpl_list(node->vpt), "<INVALID>"));
                                if (tmpl_attr_tail_num(node->vpt) != NUM_UNSPEC) {
                                        if (tmpl_attr_tail_num(node->vpt) == NUM_COUNT) {
                                                INFO_INDENT("[#]");
                                        } else if (tmpl_attr_tail_num(node->vpt) == NUM_ALL) {
                                                INFO_INDENT("[*]");
                                        } else {
                                                INFO_INDENT("[%d]", tmpl_attr_tail_num(node->vpt));
                                        }
                                }
                                INFO_INDENT("}");
                        }
                } else if (tmpl_is_data(node->vpt)) {
                        INFO_INDENT("tmpl (%s) type %s", node->fmt, fr_type_to_str(tmpl_value_type(node->vpt)));
                } else {
                        INFO_INDENT("tmpl (%s)", node->fmt);
                }
        }
                break;
 
        case XLAT_VIRTUAL:
                fr_assert(node->fmt != NULL);
                INFO_INDENT("virtual (%s)", node->fmt);
                break;
 
        case XLAT_VIRTUAL_UNRESOLVED:
                fr_assert(node->fmt != NULL);
                INFO_INDENT("virtual-unresolved (%s)", node->fmt);
                break;
 
        case XLAT_FUNC:
                fr_assert(node->call.func != NULL);
                INFO_INDENT("xlat (%s)", node->call.func->name);
                if (xlat_exp_head(node->call.args)) {
                        INFO_INDENT("{");
                        _xlat_debug_head(node->call.args, depth + 1);
                        INFO_INDENT("}");
                }
                break;
 
        case XLAT_FUNC_UNRESOLVED:
                INFO_INDENT("xlat-unresolved (%s)", node->fmt);
                if (xlat_exp_head(node->call.args)) {
                        INFO_INDENT("{");
                        _xlat_debug_head(node->call.args, depth + 1);
                        INFO_INDENT("}");
                }
                break;
 
#ifdef HAVE_REGEX
        case XLAT_REGEX:
                INFO_INDENT("regex-var -- %d", node->regex_index);
                break;
#endif
 
        case XLAT_INVALID:
                DEBUG("XLAT-INVALID");
                break;
        }
 
        depth--;
        INFO_INDENT("}");
}
 
void xlat_debug(xlat_exp_t const *node)
{
        _xlat_debug_node(node, 0);
}
 
static void _xlat_debug_head(xlat_exp_head_t const *head, int depth)
{
        int i = 0;
 
        fr_assert(head != NULL);
 
        INFO_INDENT("head flags = %s %s %s",
                    head->flags.needs_resolving ? "need_resolving," : "",
                    head->flags.pure ? "pure" : "",
                    head->flags.can_purify ? "can_purify" : "");
 
        depth++;
 
        xlat_exp_foreach(head, node) {
                INFO_INDENT("[%d] flags = %s %s %s ", i++,
                            node->flags.needs_resolving ? "need_resolving" : "",
                            node->flags.pure ? "pure" : "",
                            node->flags.can_purify ? "can_purify" : "");
 
                _xlat_debug_node(node, depth);
        }
}
 
void xlat_debug_head(xlat_exp_head_t const *head)
{
        _xlat_debug_head(head, 0);
}
 
ssize_t xlat_print_node(fr_sbuff_t *out, xlat_exp_head_t const *head, xlat_exp_t const *node,
                        fr_sbuff_escape_rules_t const *e_rules, char c)
{
        ssize_t                 slen;
        size_t                  at_in = fr_sbuff_used_total(out);
        char                    close;
 
        if (!node) return 0;
 
        switch (node->type) {
        case XLAT_GROUP:
                if (node->quote != T_BARE_WORD) FR_SBUFF_IN_CHAR_RETURN(out, fr_token_quote[node->quote]);
                xlat_print(out, node->group, fr_value_escape_by_quote[node->quote]);
                if (node->quote != T_BARE_WORD) FR_SBUFF_IN_CHAR_RETURN(out, fr_token_quote[node->quote]);
 
                if (xlat_exp_next(head, node)) {
                        if (c) FR_SBUFF_IN_CHAR_RETURN(out, c);
                        FR_SBUFF_IN_CHAR_RETURN(out, ' ');      /* Add ' ' between args */
                }
                goto done;
 
        case XLAT_BOX:
                /*
                 *      @todo - respect node->quote here, too.  Which also means updating the parser.
                 */
                if (node->quote == T_BARE_WORD) {
                        FR_SBUFF_RETURN(fr_value_box_print, out, &node->data, e_rules);
                } else {
                        FR_SBUFF_RETURN(fr_value_box_print_quoted, out, &node->data, node->quote);
                }
                goto done;
 
        case XLAT_TMPL:
                if (node->vpt->rules.cast != FR_TYPE_NULL) {
                        FR_SBUFF_IN_CHAR_RETURN(out, '(');
                        FR_SBUFF_IN_STRCPY_RETURN(out, fr_type_to_str(node->vpt->rules.cast));
                        FR_SBUFF_IN_CHAR_RETURN(out, ')');
                }
 
                if (tmpl_is_data(node->vpt)) {
                        FR_SBUFF_RETURN(fr_value_box_print_quoted, out, tmpl_value(node->vpt), node->vpt->quote);
                        goto done;
                }
                if (tmpl_needs_resolving(node->vpt)) {
                        if (node->vpt->quote != T_BARE_WORD) {
                                FR_SBUFF_IN_CHAR_RETURN(out, fr_token_quote[node->vpt->quote]);
                        }
                        FR_SBUFF_IN_STRCPY_RETURN(out, node->vpt->name); /* @todo - escape it? */
                        if (node->vpt->quote != T_BARE_WORD) {
                                FR_SBUFF_IN_CHAR_RETURN(out, fr_token_quote[node->vpt->quote]);
                        }
                        goto done;
                }
 
                if (tmpl_contains_xlat(node->vpt)) { /* xlat and exec */
                        if (node->vpt->quote == T_BARE_WORD) {
                                if (node->flags.xlat) FR_SBUFF_IN_CHAR_RETURN(out, '%', '{');
                                xlat_print(out, tmpl_xlat(node->vpt), NULL);
                                if (node->flags.xlat) FR_SBUFF_IN_CHAR_RETURN(out, '}');
                        } else {
                                FR_SBUFF_IN_CHAR_RETURN(out, fr_token_quote[node->vpt->quote]);
                                xlat_print(out, tmpl_xlat(node->vpt), fr_value_escape_by_quote[node->quote]);
                                FR_SBUFF_IN_CHAR_RETURN(out, fr_token_quote[node->vpt->quote]);
                        }
                        goto done;
                }
 
                /*
                 *      Regexes need their own print routine, as they need to print the flags, too.
                 *
                 *      Regexes should also "eat" their arguments into their instance data, so that we should
                 *      never try to print a regex.
                 */
                fr_assert(!tmpl_contains_regex(node->vpt));
 
                // attr or list
                fr_assert(tmpl_is_attr(node->vpt));
                fr_assert(talloc_parent(node->vpt) == node);
                fr_assert(!node->flags.pure);
 
                /*
                 *      We prefer the name from the configuration file, otherwise when we get
                 *      &User-Name on input, the tmpl_printer will print the full path, as
                 *      &request[0].User-Name.
                 */
                if (node->vpt->name[0] == '&') {
                        FR_SBUFF_IN_STRCPY_RETURN(out, node->fmt);
                        goto done;
                }
                break;
 
        case XLAT_ONE_LETTER:
                FR_SBUFF_IN_CHAR_RETURN(out, '%', node->fmt[0]);
                goto done;
 
        case XLAT_FUNC:
                /*
                 *      We have a callback for printing this node, go
                 *      call it.
                 */
                if (node->call.func->print) {
                        slen = node->call.func->print(out, node, node->call.inst->data, e_rules);
                        if (slen < 0) return slen;
                        goto done;
                }
                break;
 
        default:
                break;
        }
 
        /*
         *      Now print %(...) or %{...}
         */
        if ((node->type == XLAT_FUNC) || (node->type == XLAT_FUNC_UNRESOLVED)) {
                FR_SBUFF_IN_CHAR_RETURN(out, '%'); /* then the name */
                close = ')';
        } else {
                FR_SBUFF_IN_STRCPY_LITERAL_RETURN(out, "%{");
                close = '}';
        }
 
        switch (node->type) {
        case XLAT_TMPL:
                slen = tmpl_attr_print(out, node->vpt, TMPL_ATTR_REF_PREFIX_NO);
                if (slen < 0) return slen;
                break;
#ifdef HAVE_REGEX
        case XLAT_REGEX:
                FR_SBUFF_IN_SPRINTF_RETURN(out, "%i", node->regex_index);
                break;
#endif
        case XLAT_VIRTUAL:
                FR_SBUFF_IN_BSTRCPY_BUFFER_RETURN(out, node->call.func->name);
                break;
 
        case XLAT_VIRTUAL_UNRESOLVED:
                FR_SBUFF_IN_BSTRCPY_BUFFER_RETURN(out, node->fmt);
                break;
 
        case XLAT_FUNC:
                FR_SBUFF_IN_BSTRCPY_BUFFER_RETURN(out, node->call.func->name);
                FR_SBUFF_IN_CHAR_RETURN(out, '(');
 
                goto print_args;
 
        case XLAT_FUNC_UNRESOLVED:
                FR_SBUFF_IN_BSTRCPY_BUFFER_RETURN(out, node->fmt);
                FR_SBUFF_IN_CHAR_RETURN(out, '(');
 
        print_args:
                if (xlat_exp_head(node->call.args)) {
                        xlat_exp_foreach(node->call.args, child) {
                                slen = xlat_print_node(out, node->call.args, child, &xlat_escape, ',');
                                if (slen < 0) return slen;
                        }
                }
                break;
 
        case XLAT_INVALID:
        case XLAT_BOX:
        case XLAT_ONE_LETTER:
        case XLAT_GROUP:
                fr_assert_fail(NULL);
                break;
        }
        FR_SBUFF_IN_CHAR_RETURN(out, close);
 
done:
        return fr_sbuff_used_total(out) - at_in;
}
 
/** Reconstitute an xlat expression from its constituent nodes
 *
 * @param[in] out       Where to write the output string.
 * @param[in] head      First node to print.
 * @param[in] e_rules   Specifying how to escape literal values.
 */
ssize_t xlat_print(fr_sbuff_t *out, xlat_exp_head_t const *head, fr_sbuff_escape_rules_t const *e_rules)
{
        ssize_t                 slen;
        size_t                  at_in = fr_sbuff_used_total(out);
 
        xlat_exp_foreach(head, node) {
                slen = xlat_print_node(out, head, node, e_rules, 0);
                if (slen < 0) return slen - (fr_sbuff_used_total(out) - at_in);
        }
 
        return fr_sbuff_used_total(out) - at_in;
}
 
 
/** Tokenize an xlat expansion into a series of XLAT_TYPE_CHILD arguments
 *
 * @param[in] ctx               to allocate nodes in.  Note: All nodes will be
 *                              allocated in the same ctx.  This is to allow
 *                              manipulation by xlat instantiation functions
 *                              later.
 * @param[out] out              the head of the xlat list / tree structure.
 * @param[in] in                the format string to expand.
 * @param[in] xlat              we're tokenizing arguments for.
 * @param[in] p_rules           controlling how to parse the string outside of
 *                              any expansions.
 * @param[in] t_rules           controlling how attribute references are parsed.
 * @param[in] comma             whether the arguments are delimited by commas
 * @param[in] allow_attr        allow attribute references as arguments
 * @return
 *      - < 0 on error.
 *      - >0  on success which is the number of characters parsed.
 */
fr_slen_t xlat_tokenize_argv(TALLOC_CTX *ctx, xlat_exp_head_t **out, fr_sbuff_t *in,
                             xlat_t const *xlat,
                             fr_sbuff_parse_rules_t const *p_rules, tmpl_rules_t const *t_rules, bool comma, bool allow_attr)
{
        int                             argc = 0;
        fr_sbuff_t                      our_in = FR_SBUFF(in);
        ssize_t                         slen;
        fr_sbuff_marker_t               m;
        fr_sbuff_parse_rules_t const    *our_p_rules;           /* Bareword parse rules */
        fr_sbuff_parse_rules_t          tmp_p_rules;
        xlat_exp_head_t                 *head;
        xlat_arg_parser_t const         *arg = NULL;
 
        if (xlat && xlat->args) {
                arg = xlat->args;       /* Track the arguments as we parse */
        } else {
                static xlat_arg_parser_t        default_arg = { .variadic = XLAT_ARG_VARIADIC_EMPTY_SQUASH };
                arg = &default_arg;
        }
 
        MEM(head = xlat_exp_head_alloc(ctx));
        if (p_rules && p_rules->terminals) {
                tmp_p_rules = (fr_sbuff_parse_rules_t){ /* Stack allocated due to CL scope */
                        .terminals = fr_sbuff_terminals_amerge(NULL, p_rules->terminals,
                                                               value_parse_rules_bareword_quoted.terminals),
                        .escapes = (p_rules->escapes ? p_rules->escapes : value_parse_rules_bareword_quoted.escapes)
                };
                our_p_rules = &tmp_p_rules;
        } else {
                our_p_rules = &value_parse_rules_bareword_quoted;
        }
 
        /*
         *      skip spaces at the beginning as we
         *      don't want them to become a whitespace
         *      literal.
         */
        fr_sbuff_adv_past_whitespace(in, SIZE_MAX, NULL);
        fr_sbuff_marker(&m, &our_in);
 
        while (fr_sbuff_extend(&our_in)) {
                xlat_exp_t      *node = NULL;
                fr_token_t      quote;
                char            *fmt;
                size_t          len;
 
                fr_sbuff_set(&m, &our_in);      /* Record start of argument */
                argc++;
 
                /*
                 *      Whitespace isn't significant for comma-separated argvs
                 */
                if (comma) fr_sbuff_adv_past_whitespace(&our_in, SIZE_MAX, NULL);
 
                fr_sbuff_out_by_longest_prefix(&slen, &quote, xlat_quote_table, &our_in, T_BARE_WORD);
 
                /*
                 *      Alloc a new node to hold the child nodes
                 *      that make up the argument.
                 */
                MEM(node = xlat_exp_alloc(head, XLAT_GROUP, NULL, 0));
                node->quote = quote;
 
                switch (quote) {
                /*
                 *      Barewords --may-contain=%{expansions}
                 */
                case T_BARE_WORD:
                        XLAT_DEBUG("ARGV bare word <-- %.*s", (int) fr_sbuff_remaining(&our_in), fr_sbuff_current(&our_in));
 
                        /*
                         *      &User-Name is an attribute reference
                         *
                         *      @todo - only the mono functions allow this automatic conversion.
                         *      The input args ones (e.g. immutable) take an input string, and parse the tmpl from that.
                         *
                         *      We need to signal the tokenize / eval code that the parameter here is a tmpl, and not a string.
                         *
                         *      Perhaps &"foo" can dynamically create the string, and then pass it to the the
                         *      tmpl tokenizer, and then pass the tmpl to the function.  Which also means that
                         *      we need to be able to have a fr_value_box_t which holds a ptr to a tmpl.  And
                         *      update the function arguments to say "we want a tmpl, not a string".
                         */
                        if (allow_attr && fr_sbuff_is_char(&our_in, '&')) {
                                if (xlat_tokenize_attribute(node->group, &our_in, our_p_rules, t_rules, TMPL_ATTR_REF_PREFIX_YES) < 0) goto error;
                                break;
                        }
 
                        if (xlat_tokenize_input(node->group, &our_in,
                                                our_p_rules, t_rules, arg->safe_for) < 0) {
                        error:
                                if (our_p_rules != &value_parse_rules_bareword_quoted) {
                                        talloc_const_free(our_p_rules->terminals);
                                }
                                talloc_free(head);
 
                                FR_SBUFF_ERROR_RETURN(&our_in); /* error */
                        }
                        break;
 
                /*
                 *      "Double quoted strings may contain %{expansions}"
                 */
                case T_DOUBLE_QUOTED_STRING:
                        XLAT_DEBUG("ARGV double quotes <-- %.*s", (int) fr_sbuff_remaining(&our_in), fr_sbuff_current(&our_in));
 
                        if (xlat_tokenize_input(node->group, &our_in,
                                                &value_parse_rules_double_quoted, t_rules, arg->safe_for) < 0) goto error;
                        break;
 
                /*
                 *      'Single quoted strings get parsed as literal strings'
                 */
                case T_SINGLE_QUOTED_STRING:
                {
                        char            *str;
                        xlat_exp_t      *child;
 
                        XLAT_DEBUG("ARGV single quotes <-- %.*s", (int) fr_sbuff_remaining(&our_in), fr_sbuff_current(&our_in));
 
                        child = xlat_exp_alloc(node->group, XLAT_BOX, NULL, 0);
                        slen = fr_sbuff_out_aunescape_until(child, &str, &our_in, SIZE_MAX,
                                                            value_parse_rules_single_quoted.terminals,
                                                            value_parse_rules_single_quoted.escapes);
                        if (slen < 0) goto error;
 
                        xlat_exp_set_name_buffer_shallow(child, str);
                        fr_value_box_strdup(child, &child->data, NULL, str, false);
                        fr_value_box_mark_safe_for(&child->data, arg->safe_for);        /* Literal values are treated as implicitly safe */
                        child->flags.constant = true;
                        fr_assert(child->flags.pure);
                        xlat_exp_insert_tail(node->group, child);
                }
                        break;
 
                /*
                 *      `back quoted strings aren't supported`
                 */
                case T_BACK_QUOTED_STRING:
                        fr_strerror_const("Unexpected `...` string");
                        goto error;
 
                default:
                        fr_assert(0);
                        break;
                }
 
                if ((quote != T_BARE_WORD) && !fr_sbuff_next_if_char(&our_in, fr_token_quote[quote])) { /* Quoting */
                        fr_strerror_const("Unterminated string");
                        fr_sbuff_set(&our_in, &m);
                        goto error;
                }
 
                fmt = talloc_bstrndup(node, fr_sbuff_current(&m), fr_sbuff_behind(&m));
                xlat_exp_set_name_buffer_shallow(node, fmt);
 
                node->flags = node->group->flags;
 
                xlat_exp_insert_tail(head, node);
 
                /*
                 *      If we're not and the end of the string
                 *      and there's no whitespace between tokens
                 *      then error.
                 */
                fr_sbuff_set(&m, &our_in);
                len = fr_sbuff_adv_past_whitespace(&our_in, SIZE_MAX, NULL);
 
               /*
                *       Commas are in the list of terminals, but we skip over them,
                */
                if (comma) {
                        fr_assert(p_rules && p_rules->terminals);
 
                        if (fr_sbuff_next_if_char(&our_in, ',')) {
                                continue;
                        }
 
                        if (fr_sbuff_is_char(&our_in, ')')) break;
 
                        fr_strerror_printf("Unexpected text after argument %d", argc);
                        goto error;
                }
 
                /*
                 *      Check to see if we have a terminal char
                 */
                if ((p_rules && p_rules->terminals) && fr_sbuff_is_terminal(&our_in, p_rules->terminals)) break;
 
                /*
                 *      Otherwise, if we can extend, and found
                 *      no additional whitespace, it means two
                 *      arguments were smushed together.
                 */
                if (fr_sbuff_extend(&our_in) && (len == 0)) {
                        fr_strerror_const("Unexpected text after argument");
                        goto error;
                }
 
                if (!arg->variadic) {
                        arg++;
                        if (arg->type == FR_TYPE_NULL) {
                                fr_strerror_printf("Too many arguments, expected %u", argc - 1);
                                goto error;
                        }
                }
        }
 
        if (our_p_rules != &value_parse_rules_bareword_quoted) talloc_const_free(our_p_rules->terminals);
 
        XLAT_HEAD_VERIFY(head);
        *out = head;
 
        FR_SBUFF_SET_RETURN(in, &our_in);
}
 
/** Tokenize an xlat expansion
 *
 * @param[in] ctx                       to allocate dynamic buffers in.
 * @param[out] out                      the head of the xlat list / tree structure.
 * @param[in] in                        the format string to expand.
 * @param[in] p_rules                   controlling how the string containing the xlat
 *                                      expansions should be parsed.
 * @param[in] t_rules                   controlling how attribute references are parsed.
 *                                      Do NOT alter this function to take tmpl_rules_t
 *                                      as this provides another value for literals_safe_for
 *                                      and this gets very confusing.
 * @param[in] literals_safe_for         the safe_for value to assign to any literals occurring at the
 *                                      top level of the expansion.
 * @return
 *      - >0 on success.
 *      - 0 and *head == NULL - Parse failure on first char.
 *      - 0 and *head != NULL - Zero length expansion
 *      - < 0 the negative offset of the parse failure.
 */
fr_slen_t xlat_tokenize(TALLOC_CTX *ctx, xlat_exp_head_t **out, fr_sbuff_t *in,
                        fr_sbuff_parse_rules_t const *p_rules, tmpl_rules_t const *t_rules,
                        fr_value_box_safe_for_t literals_safe_for)
{
        fr_sbuff_t      our_in = FR_SBUFF(in);
        xlat_exp_head_t *head;
 
 
        MEM(head = xlat_exp_head_alloc(ctx));
        fr_strerror_clear();    /* Clear error buffer */
 
        if (xlat_tokenize_input(head, &our_in, p_rules, t_rules, literals_safe_for) < 0) {
                talloc_free(head);
                FR_SBUFF_ERROR_RETURN(&our_in);
        }
 
        /*
         *      Add nodes that need to be bootstrapped to
         *      the registry.
         */
        if (xlat_finalize(head, t_rules->xlat.runtime_el) < 0) {
                talloc_free(head);
                return 0;
        }
 
        XLAT_HEAD_VERIFY(head);
        *out = head;
 
        FR_SBUFF_SET_RETURN(in, &our_in);
}
 
/** Check to see if the expansion consists entirely of value-box elements
 *
 * @param[in] head      to check.
 * @return
 *      - true if expansion contains only literal elements.
 *      - false if expansion contains expandable elements.
 */
bool xlat_is_literal(xlat_exp_head_t const *head)
{
        xlat_exp_foreach(head, node) {
                if (node->type != XLAT_BOX) return false;
        }
 
        return true;
}
 
/** Check to see if the expansion needs resolving
 *
 * @param[in] head      to check.
 * @return
 *      - true if expansion needs resolving
 *      - false otherwise
 */
bool xlat_needs_resolving(xlat_exp_head_t const *head)
{
        return head->flags.needs_resolving;
}
 
/** Convert an xlat node to an unescaped literal string and free the original node
 *
 *  This is really "unparse the xlat nodes, and convert back to their original string".
 *
 * @param[in] ctx       to allocate the new string in.
 * @param[out] str      a duplicate of the node's fmt string.
 * @param[in,out] head  to convert.
 * @return
 *      - true  the tree consists of a single value node which was converted.
 *      - false the tree was more complex than a single literal, op was a noop.
 */
bool xlat_to_string(TALLOC_CTX *ctx, char **str, xlat_exp_head_t **head)
{
        fr_sbuff_t              out;
        fr_sbuff_uctx_talloc_t  tctx;
        size_t                  len = 0;
 
        if (!*head) return false;
 
        /*
         *      Instantiation functions may chop
         *      up the node list into multiple
         *      literals, so we need to walk the
         *      list until we find a non-literal.
         */
        xlat_exp_foreach(*head, node) {
                if (node->type != XLAT_BOX) return false;
                len += talloc_array_length(node->fmt) - 1;
        }
 
        fr_sbuff_init_talloc(ctx, &out, &tctx, len, SIZE_MAX);
 
        xlat_exp_foreach(*head, node) {
                fr_sbuff_in_bstrcpy_buffer(&out, node->fmt);
        }
 
        *str = fr_sbuff_buff(&out);     /* No need to trim, should be the correct length */
 
        return true;
}
 
/** Walk over an xlat tree recursively, resolving any unresolved functions or references
 *
 * @param[in,out] head          of xlat tree to resolve.
 * @param[in] xr_rules          Specifies rules to use for resolution passes after initial
 *                              tokenization.
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
int xlat_resolve(xlat_exp_head_t *head, xlat_res_rules_t const *xr_rules)
{
        static xlat_res_rules_t         xr_default;
        xlat_flags_t                    our_flags;
 
        if (!head->flags.needs_resolving) return 0;                     /* Already done */
 
        if (!xr_rules) xr_rules = &xr_default;
 
        our_flags = head->flags;
        our_flags.needs_resolving = false;                      /* We flip this if not all resolutions are successful */
        our_flags.pure = true;                                  /* we flip this if the children are not pure */
 
        xlat_exp_foreach(head, node) {
                /*
                 *      This node and none of its children need resolving
                 */
                if (!node->flags.needs_resolving) {
                        xlat_flags_merge(&our_flags, &node->flags);
                        continue;
                }
 
                switch (node->type) {
                case XLAT_GROUP:
                        if (xlat_resolve(node->group, xr_rules) < 0) return -1;
                        node->flags = node->group->flags;
                        break;
 
                /*
                 *      An unresolved function.
                 */
                case XLAT_FUNC_UNRESOLVED:
                        /*
                         *      Try to find the function
                         */
                        node->call.func = xlat_func_find(node->fmt, talloc_array_length(node->fmt) - 1);
                        if (!node->call.func) {
                                /*
                                 *      FIXME - Produce proper error with marker
                                 */
                                if (!xr_rules->allow_unresolved) {
                                        fr_strerror_printf("Failed resolving function \"%pV\"",
                                                           fr_box_strvalue_buffer(node->fmt));
                                        return -1;
                                }
                                break;
                        }
 
                        xlat_exp_set_type(node, XLAT_FUNC);
                        node->call.dict = xr_rules->tr_rules->dict_def;
 
                        /*
                         *      Check input arguments of our freshly
                         *      resolved function
                         */
                        switch (node->call.func->input_type) {
                        case XLAT_INPUT_UNPROCESSED:
                                break;
 
                        case XLAT_INPUT_MONO:
                                if (node->call.input_type != XLAT_INPUT_MONO) {
                                        fr_strerror_const("Function should be called using %{func:arg} syntax");
                                        return -1;
 
                                }
                                if (xlat_validate_function_mono(node) < 0) return -1;
                                break;
 
                        case XLAT_INPUT_ARGS:
                                if (node->call.input_type != XLAT_INPUT_ARGS) {
                                        fr_strerror_const("Function takes defined arguments and should "
                                                          "be called using %(func:args) syntax");
                                        return -1;
                                }
                                if (xlat_validate_function_args(node) < 0) return -1;
                                break;
                        }
 
                        /*
                         *      Add the freshly resolved function
                         *      to the bootstrap tree.
                         */
                        if (xlat_instance_register_func(node) < 0) return -1;
 
                        /*
                         *      The function is now resolved, so we go through the normal process of resolving
                         *      its arguments, etc.
                         */
                        FALL_THROUGH;
 
                /*
                 *      A resolved function with unresolved args
                 */
                case XLAT_FUNC:
                        node->flags = node->call.func->flags;
 
                        if (node->call.func->resolve) {
                                void *inst = node->call.inst ? node->call.inst->data : NULL;
 
                                if (node->call.func->resolve(node, inst, xr_rules) < 0) return -1;
                        } else {
                                if (xlat_resolve(node->call.args, xr_rules) < 0) return -1;
                        }
 
                        xlat_flags_merge(&node->flags, &node->call.args->flags);
                        node->flags.can_purify = (node->call.func->flags.pure && node->call.args->flags.pure) | node->call.args->flags.can_purify;
                        break;
 
                /*
                 *      This covers unresolved attributes as well as
                 *      unresolved functions.
                 */
                case XLAT_VIRTUAL_UNRESOLVED:
                {
                        if (xlat_resolve_virtual_attribute(node, node->vpt) == 0) break;
 
                        /*
                         *      Try and resolve (in-place) as an attribute
                         */
                        if ((tmpl_resolve(node->vpt, xr_rules->tr_rules) < 0) ||
                            (node->vpt->type != TMPL_TYPE_ATTR)) {
                                /*
                                 *      FIXME - Produce proper error with marker
                                 */
                                if (!xr_rules->allow_unresolved) {
                                error_unresolved:
                                        if (node->quote == T_BARE_WORD) {
                                                fr_strerror_printf_push("Failed resolving expansion: %s",
                                                                        node->fmt);
                                        } else {
                                                fr_strerror_printf_push("Failed resolving expansion: %c%s%c",
                                                                        fr_token_quote[node->quote], node->fmt, fr_token_quote[node->quote]);
                                        }
                                        return -1;
                                }
                                break;
                        }
 
                        /*
                         *      Just need to flip the type as the tmpl should already have been fixed up
                         */
                        xlat_exp_set_type(node, XLAT_TMPL);
 
                        /*
                         *      Reset node flags.  Attributes aren't pure, and don't need further resolving.
                         */
                        node->flags = (xlat_flags_t){ };
                }
                        break;
 
                case XLAT_TMPL:
                        /*
                         *      Double-quoted etc. strings may contain xlats, so we try to resolve them now.
                         *      Or, convert them to data.
                         */
                        if (tmpl_resolve(node->vpt, xr_rules->tr_rules) < 0) return -1;
 
                        node->flags.needs_resolving = false;
                        node->flags.pure = tmpl_is_data(node->vpt);
                        break;
 
 
                default:
                        fr_assert(0);   /* Should not have been marked as unresolved */
                        return -1;
                }
 
                if (node->flags.needs_resolving && !xr_rules->allow_unresolved) goto error_unresolved;
 
                xlat_flags_merge(&our_flags, &node->flags);
        }
 
        head->flags = our_flags;
 
        return 0;
}
 
 
/** Try to convert an xlat to a tmpl for efficiency
 *
 * @param ctx to allocate new tmpl_t in.
 * @param head to convert.
 * @return
 *      - NULL if unable to convert (not necessarily error).
 *      - A new #tmpl_t.
 */
tmpl_t *xlat_to_tmpl_attr(TALLOC_CTX *ctx, xlat_exp_head_t *head)
{
        tmpl_t *vpt;
        xlat_exp_t *node = xlat_exp_head(head);
 
        if (!node || (node->type != XLAT_TMPL) || !tmpl_is_attr(node->vpt)) return NULL;
 
        /*
         *   Concat means something completely different as an attribute reference
         *   Count isn't implemented.
         */
        if ((tmpl_attr_tail_num(node->vpt) == NUM_COUNT) || (tmpl_attr_tail_num(node->vpt) == NUM_ALL)) return NULL;
 
        vpt = tmpl_alloc(ctx, TMPL_TYPE_ATTR, T_BARE_WORD, node->fmt, talloc_array_length(node->fmt) - 1);
        if (!vpt) return NULL;
 
        tmpl_attr_copy(vpt, node->vpt);
 
        TMPL_VERIFY(vpt);
 
        return vpt;
}
 
/** Convert attr tmpl to an xlat for &attr[*]
 *
 * @param[in] ctx       to allocate new expansion in.
 * @param[out] out      Where to write new xlat node.
 * @param[in,out] vpt_p to convert to xlat expansion.
 *                      Will be set to NULL on completion
 * @return
 *      - 0 on success.
 *      - -1 on failure.
 */
int xlat_from_tmpl_attr(TALLOC_CTX *ctx, xlat_exp_head_t **out, tmpl_t **vpt_p)
{
        xlat_exp_t      *node;
        xlat_t          *func;
        tmpl_t          *vpt = *vpt_p;
        xlat_exp_head_t *head;
 
        if (!tmpl_is_attr(vpt) && !tmpl_is_attr_unresolved(vpt)) return 0;
 
        MEM(head = xlat_exp_head_alloc(ctx));
 
        /*
         *      If it's a single attribute reference
         *      see if it's actually a virtual attribute.
         */
        if ((tmpl_attr_num_elements(vpt) == 1) ||
            (((tmpl_attr_list_head(tmpl_attr(vpt))->da) == request_attr_request) && tmpl_attr_num_elements(vpt) == 2)) {
                if (tmpl_is_attr_unresolved(vpt)) {
                        func = xlat_func_find(tmpl_attr_tail_unresolved(vpt), -1);
                        if (!func) {
                                node = xlat_exp_alloc(head, XLAT_VIRTUAL_UNRESOLVED, vpt->name, vpt->len);
 
                                /*
                                 *      FIXME - Need a tmpl_copy function to
                                 *      the assignment of the tmpl to the new
                                 *      xlat expression
                                 */
                                node->vpt = talloc_move(node, vpt_p);
                                node->flags = (xlat_flags_t) { .needs_resolving = true };
                                goto done;
                        }
 
                        node = xlat_exp_alloc(head, XLAT_VIRTUAL, vpt->name, vpt->len);
                        node->vpt = talloc_move(node, vpt_p);
                        node->call.func = func;
                        node->flags = func->flags;
                        goto done;
                }
        }
 
        node = xlat_exp_alloc(head, XLAT_TMPL, vpt->name, vpt->len);
        node->vpt = talloc_move(node, vpt_p);
        fr_assert(!node->flags.pure);
 
done:
        xlat_exp_insert_tail(head, node);
        *out = head;
 
        return 0;
}