switch.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: 62df4b1d6ac53bf70d97d8f04c30fd55ab89f825 $
 *
 * @file unlang/switch.c
 * @brief Unlang "switch" keyword evaluation.
 *
 * @copyright 2006-2019 The FreeRADIUS server project
 */
RCSID("$Id: 62df4b1d6ac53bf70d97d8f04c30fd55ab89f825 $")
 
#include <freeradius-devel/server/rcode.h>
#include "group_priv.h"
#include "switch_priv.h"
#include "xlat_priv.h"
 
static unlang_action_t unlang_switch(UNUSED unlang_result_t *p_result, request_t *request, unlang_stack_frame_t *frame)
{
        unlang_t                *found;
 
        unlang_group_t          *switch_g;
        unlang_switch_t         *switch_gext;
 
        fr_value_box_t const    *box = NULL;
 
        fr_pair_t               *vp;
 
        /*
         *      Mock up an unlang_cast_t.  Note that these on-stack
         *      buffers are the reason why case_cmp(), case_hash(),
         *      and case_to_key() use direct casts, and not the
         *      "generic to x" functions.
         */
        tmpl_t                  case_vpt = (tmpl_t) {
                                        .type = TMPL_TYPE_DATA,
                                };
        unlang_case_t           my_case = (unlang_case_t) {
                                        .group = (unlang_group_t) {
                                                .self = (unlang_t) {
                                                        .type = UNLANG_TYPE_CASE,
                                                },
                                        },
                                        .vpt = &case_vpt,
                                };
 
        switch_g = unlang_generic_to_group(frame->instruction);
        switch_gext = unlang_group_to_switch(switch_g);
 
        found = NULL;
 
        /*
         *      The attribute doesn't exist.  We can skip
         *      directly to the default 'case' statement.
         */
        if (tmpl_is_attr(switch_gext->vpt)) {
                if (tmpl_find_vp(&vp, request, switch_gext->vpt) < 0) {
                        found = switch_gext->default_case;
                        goto do_null_case;
                } else {
                        box = &vp->data;
                }
 
        /*
         *      Expand the template if necessary, so that it
         *      is evaluated once instead of for each 'case'
         *      statement.
         */
        } else if (tmpl_is_xlat(switch_gext->vpt) ||
                   tmpl_is_exec(switch_gext->vpt)) {
                ssize_t slen;
 
                slen = tmpl_aexpand_type(unlang_interpret_frame_talloc_ctx(request), &box, FR_TYPE_VALUE_BOX,
                                         request, switch_gext->vpt);
                if (slen < 0) {
                        RDEBUG("Switch failed expanding %s - %s", switch_gext->vpt->name, fr_strerror());
                        goto find_null_case;
                }
        } else if (!fr_cond_assert_msg(0, "Invalid tmpl type %s", tmpl_type_to_str(switch_gext->vpt->type))) {
                return UNLANG_ACTION_FAIL;
        }
 
        /*
         *      case_gext->vpt.data.literal is an in-line box, so we
         *      have to make a shallow copy of its contents.
         *
         *      Note: We do not pass a ctx here as we don't want to
         *      create a reference.
         */
        fr_value_box_copy_shallow(NULL, &case_vpt.data.literal, box);
        found = fr_htrie_find(switch_gext->ht, &my_case);
        if (!found) {
        find_null_case:
                found = switch_gext->default_case;
        }
 
do_null_case:
        /*
         *      Nothing found.  Just continue, and ignore the "switch"
         *      statement.
         */
        if (!found) {
                if (box) {
                        RWDEBUG("Failed to find 'case' target for value %pV", box);
                } else {
                        RWDEBUG("Failed to find 'default' target when expansion of %s returning no value",
                                switch_gext->vpt->name);
                }
                return UNLANG_ACTION_EXECUTE_NEXT;
        }
 
        if (unlang_interpret_push(NULL, request, found, FRAME_CONF(RLM_MODULE_NOT_SET, UNLANG_SUB_FRAME), UNLANG_NEXT_STOP) < 0) {
                RETURN_UNLANG_ACTION_FATAL;
        }
 
        return UNLANG_ACTION_PUSHED_CHILD;
}
 
 
static unlang_action_t unlang_case(unlang_result_t *p_result, request_t *request, unlang_stack_frame_t *frame)
{
        unlang_group_t          *g = unlang_generic_to_group(frame->instruction);
 
        if (unlang_list_empty(&g->children)) RETURN_UNLANG_NOOP;
 
        return unlang_group(p_result, request, frame);
}
 
 
static unlang_t *unlang_compile_case(unlang_t *parent, unlang_compile_ctx_t *unlang_ctx, CONF_ITEM const *ci)
{
        CONF_SECTION            *cs = cf_item_to_section(ci);
        int                     i;
        char const              *name2;
        unlang_t                *c;
        unlang_group_t          *case_g;
        unlang_case_t           *case_gext;
        tmpl_t                  *vpt = NULL;
        tmpl_rules_t            t_rules;
 
        /*
         *      We allow unknown attributes here.
         */
        t_rules = *(unlang_ctx->rules);
        t_rules.attr.allow_unknown = true;
        RULES_VERIFY(&t_rules);
 
        if (!parent || (parent->type != UNLANG_TYPE_SWITCH)) {
                cf_log_err(cs, "\"case\" statements may only appear within a \"switch\" section");
                cf_log_err(ci, DOC_KEYWORD_REF(case));
                return NULL;
        }
 
        /*
         *      case THING means "match THING"
         *      case       means "match anything"
         */
        name2 = cf_section_name2(cs);
        if (name2) {
                ssize_t                 slen;
                fr_token_t              quote;
                unlang_group_t          *switch_g;
                unlang_switch_t         *switch_gext;
 
                switch_g = unlang_generic_to_group(parent);
                switch_gext = unlang_group_to_switch(switch_g);
 
                fr_assert(switch_gext->vpt != NULL);
 
                /*
                 *      We need to cast case values to match
                 *      what we're switching over, otherwise
                 *      integers of different widths won't
                 *      match.
                 */
                t_rules.cast = tmpl_expanded_type(switch_gext->vpt);
 
                /*
                 *      Need to pass the attribute from switch
                 *      to tmpl rules so we can convert the
                 *      case string to an integer value.
                 */
                if (tmpl_is_attr(switch_gext->vpt)) {
                        fr_dict_attr_t const *da = tmpl_attr_tail_da(switch_gext->vpt);
                        if (da->flags.has_value) t_rules.enumv = da;
                }
 
                quote = cf_section_name2_quote(cs);
 
                slen = tmpl_afrom_substr(cs, &vpt,
                                         &FR_SBUFF_IN_STR(name2),
                                         quote,
                                         NULL,
                                         &t_rules);
                if (!vpt) {
                        cf_canonicalize_error(cs, slen, "Failed parsing argument to 'case'", name2);
                        return NULL;
                }
 
                /*
                 *      Bare word strings are attribute references
                 */
                if (tmpl_is_attr(vpt) || tmpl_is_attr_unresolved(vpt)) {
                fail_attr:
                        cf_log_err(cs, "arguments to 'case' statements MUST NOT be attribute references.");
                        goto fail;
                }
 
                if (!tmpl_is_data(vpt) || tmpl_is_data_unresolved(vpt)) {
                        cf_log_err(cs, "arguments to 'case' statements MUST be static data.");
                fail:
                        talloc_free(vpt);
                        return NULL;
                }
 
                /*
                 *      References to unresolved attributes are forbidden.  They are no longer "bare word
                 *      strings".
                 */
                if ((quote == T_BARE_WORD) && (tmpl_value_type(vpt) == FR_TYPE_STRING)) {
                        goto fail_attr;
                }
 
        } /* else it's a default 'case' statement */
 
        /*
         *      If we were asked to match something, then we MUST
         *      match it, even if the section is empty.  Otherwise we
         *      will silently skip the match, and then fall through to
         *      the "default" statement.
         */
        c = unlang_compile_section(parent, unlang_ctx, cs, UNLANG_TYPE_CASE);
        if (!c) {
                talloc_free(vpt);
                return NULL;
        }
 
        case_g = unlang_generic_to_group(c);
        case_gext = unlang_group_to_case(case_g);
        case_gext->vpt = talloc_steal(case_gext, vpt);
 
        /*
         *      Set all of it's codes to return, so that
         *      when we pick a 'case' statement, we don't
         *      fall through to processing the next one.
         */
        for (i = 0; i < RLM_MODULE_NUMCODES; i++) c->actions.actions[i] = MOD_ACTION_RETURN;
 
        return c;
}
 
static int8_t case_cmp(void const *one, void const *two)
{
        unlang_case_t const *a = (unlang_case_t const *) one; /* may not be talloc'd! See switch.c */
        unlang_case_t const *b = (unlang_case_t const *) two; /* may not be talloc'd! */
 
        return fr_value_box_cmp(tmpl_value(a->vpt), tmpl_value(b->vpt));
}
 
static uint32_t case_hash(void const *data)
{
        unlang_case_t const *a = (unlang_case_t const *) data; /* may not be talloc'd! */
 
        return fr_value_box_hash(tmpl_value(a->vpt));
}
 
static int case_to_key(uint8_t **out, size_t *outlen, void const *data)
{
        unlang_case_t const *a = (unlang_case_t const *) data; /* may not be talloc'd! */
 
        return fr_value_box_to_key(out, outlen, tmpl_value(a->vpt));
}
 
static unlang_t *unlang_compile_switch(unlang_t *parent, unlang_compile_ctx_t *unlang_ctx, CONF_ITEM const *ci)
{
        CONF_SECTION            *cs = cf_item_to_section(ci);
        CONF_ITEM               *subci;
        fr_token_t              token;
        char const              *name1, *name2;
        char const              *type_name;
 
        unlang_group_t          *g;
        unlang_switch_t         *gext;
 
        unlang_t                *c;
        ssize_t                 slen;
 
        tmpl_rules_t            t_rules;
 
        fr_type_t               type;
        fr_htrie_type_t         htype;
 
        /*
         *      We allow unknown attributes here.
         */
        t_rules = *(unlang_ctx->rules);
        t_rules.attr.allow_unknown = true;
        RULES_VERIFY(&t_rules);
 
        name2 = cf_section_name2(cs);
        if (!name2) {
                cf_log_err(cs, "You must specify a variable to switch over for 'switch'");
        print_url:
                cf_log_err(ci, DOC_KEYWORD_REF(switch));
                return NULL;
        }
 
        if (!cf_item_next(cs, NULL)) return UNLANG_IGNORE;
 
        g = unlang_group_allocate(parent, cs, UNLANG_TYPE_SWITCH);
        if (!g) return NULL;
 
        gext = unlang_group_to_switch(g);
 
        /*
         *      Create the template.  All attributes and xlats are
         *      defined by now.
         *
         *      The 'case' statements need g->vpt filled out to ensure
         *      that the data types match.
         */
        token = cf_section_name2_quote(cs);
 
        if ((token == T_BARE_WORD) && (name2[0] != '%')) {
                slen = tmpl_afrom_attr_substr(gext, NULL, &gext->vpt,
                                              &FR_SBUFF_IN_STR(name2),
                                              NULL,
                                              &t_rules);
        } else {
                slen = tmpl_afrom_substr(gext, &gext->vpt,
                                         &FR_SBUFF_IN_STR(name2),
                                         token,
                                         NULL,
                                         &t_rules);
        }
        if (!gext->vpt) {
                cf_canonicalize_error(cs, slen, "Failed parsing argument to 'switch'", name2);
                talloc_free(g);
                return NULL;
        }
 
        c = unlang_group_to_generic(g);
        c->name = "switch";
        c->debug_name = talloc_typed_asprintf(c, "switch %s", name2);
 
        /*
         *      Fixup the template before compiling the children.
         *      This is so that compile_case() can do attribute type
         *      checks / casts against us.
         */
        if (!pass2_fixup_tmpl(g, &gext->vpt, cf_section_to_item(cs), unlang_ctx->rules->attr.dict_def)) {
                talloc_free(g);
                return NULL;
        }
 
        if (tmpl_is_list(gext->vpt)) {
                cf_log_err(cs, "Cannot use list for 'switch' statement");
        error:
                talloc_free(g);
                goto print_url;
        }
 
        if (tmpl_contains_regex(gext->vpt)) {
                cf_log_err(cs, "Cannot use regular expression for 'switch' statement");
                goto error;
        }
 
        if (tmpl_is_data(gext->vpt)) {
                cf_log_err(cs, "Cannot use constant data for 'switch' statement");
                goto error;
        }
 
        if (tmpl_is_xlat(gext->vpt)) {
                xlat_exp_head_t *xlat = tmpl_xlat(gext->vpt);
 
                if (xlat->flags.constant || xlat->flags.pure) {
                        cf_log_err(cs, "Cannot use constant data for 'switch' statement");
                        goto error;
                }
        }
 
 
        if (tmpl_needs_resolving(gext->vpt)) {
                cf_log_err(cs, "Cannot resolve key for 'switch' statement");
                goto error;
        }
 
        type_name = cf_section_argv(cs, 0); /* AFTER name1, name2 */
        if (type_name) {
                type = fr_table_value_by_str(fr_type_table, type_name, FR_TYPE_NULL);
 
                /*
                 *      Should have been caught in cf_file.c, process_switch()
                 */
                fr_assert(type != FR_TYPE_NULL);
                fr_assert(fr_type_is_leaf(type));
 
        do_cast:
                if (tmpl_cast_set(gext->vpt, type) < 0) {
                        cf_log_perr(cs, "Failed setting cast type");
                        goto error;
                }
 
        } else {
                /*
                 *      Get the return type of the tmpl.  If we don't know,
                 *      mash it all to string.
                 */
                type = tmpl_data_type(gext->vpt);
                if ((type == FR_TYPE_NULL) || (type == FR_TYPE_VOID)) {
                        type = FR_TYPE_STRING;
                        goto do_cast;
                }
        }
 
        htype = fr_htrie_hint(type);
        if (htype == FR_HTRIE_INVALID) {
                cf_log_err(cs, "Invalid data type '%s' used for 'switch' statement",
                            fr_type_to_str(type));
                goto error;
        }
 
        gext->ht = fr_htrie_alloc(gext, htype,
                                  (fr_hash_t) case_hash,
                                  (fr_cmp_t) case_cmp,
                                  (fr_trie_key_t) case_to_key,
                                  NULL);
        if (!gext->ht) {
                cf_log_err(cs, "Failed initializing internal data structures");
                talloc_free(g);
                return NULL;
        }
 
        /*
         *      Walk through the children of the switch section,
         *      ensuring that they're all 'case' statements, and then compiling them.
         */
        for (subci = cf_item_next(cs, NULL);
             subci != NULL;
             subci = cf_item_next(cs, subci)) {
                CONF_SECTION *subcs;
                unlang_t *single;
                unlang_case_t   *case_gext;
 
                if (!cf_item_is_section(subci)) {
                        if (!cf_item_is_pair(subci)) continue;
 
                        cf_log_err(subci, "\"switch\" sections can only have \"case\" subsections");
                        goto error;
                }
 
                subcs = cf_item_to_section(subci);      /* can't return NULL */
                name1 = cf_section_name1(subcs);
 
                if (strcmp(name1, "case") != 0) {
                        /*
                         *      We finally support "default" sections for "switch".
                         */
                        if (strcmp(name1, "default") == 0) {
                                if (cf_section_name2(subcs) != 0) {
                                        cf_log_err(subci, "\"default\" sections cannot have a match argument");
                                        goto error;
                                }
                                goto handle_default;
                        }
 
                        cf_log_err(subci, "\"switch\" sections can only have \"case\" subsections");
                        goto error;
                }
 
                name2 = cf_section_name2(subcs);
                if (!name2) {
                handle_default:
                        if (gext->default_case) {
                                cf_log_err(subci, "Cannot have two 'default' case statements");
                                goto error;
                        }
                }
 
                /*
                 *      Compile the subsection.
                 */
                single = unlang_compile_case(c, unlang_ctx, subci);
                if (!single) goto error;
 
                fr_assert(single->type == UNLANG_TYPE_CASE);
 
                /*
                 *      Remember the "default" section, and insert the
                 *      non-default "case" into the htrie.
                 */
                case_gext = unlang_group_to_case(unlang_generic_to_group(single));
                if (!case_gext->vpt) {
                        gext->default_case = single;
 
                } else if (!fr_htrie_insert(gext->ht, single)) {
                        single = fr_htrie_find(gext->ht, single);
 
                        /*
                         *      @todo - look up the key and get the previous one?
                         */
                        cf_log_err(subci, "Failed inserting 'case' statement.  Is there a duplicate?");
 
                        if (single) cf_log_err(unlang_generic_to_group(single)->cs, "Duplicate may be here.");
 
                        goto error;
                }
 
                unlang_list_insert_tail(&g->children, single);
        }
 
        return c;
}
 
void unlang_switch_init(void)
{
        unlang_register(&(unlang_op_t) {
                        .name = "switch",
                        .type = UNLANG_TYPE_SWITCH,
                        .flag = UNLANG_OP_FLAG_DEBUG_BRACES,
 
                        .compile = unlang_compile_switch,
                        .interpret = unlang_switch,
 
                        .unlang_size = sizeof(unlang_switch_t),
                        .unlang_name = "unlang_switch_t",
 
                        .pool_headers = TMPL_POOL_DEF_HEADERS,
                        .pool_len = TMPL_POOL_DEF_LEN
                });
 
 
        unlang_register(&(unlang_op_t){
                        .name = "case",
                        .type = UNLANG_TYPE_CASE,
                        .flag = UNLANG_OP_FLAG_DEBUG_BRACES | UNLANG_OP_FLAG_BREAK_POINT,
 
                        .compile = unlang_compile_case,
                        .interpret = unlang_case,
 
                        .unlang_size = sizeof(unlang_case_t),
                        .unlang_name = "unlang_case_t",
                });
}