/*

 *   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: 1118af5632d0bec589a846b9bc001c06c29e9253 $

 *

 * @file unlang/switch.c

 * @brief Unlang "switch" keyword evaluation.

 *

 * @copyright 2006-2019 The FreeRADIUS server project

 */

RCSID("$Id: 1118af5632d0bec589a846b9bc001c06c29e9253 $")

#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, *to_free = 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;

    }

    to_free = box;

  } 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);

  fr_htrie_find((void **)&found, 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);

    }

    talloc_const_free(to_free);

    return UNLANG_ACTION_EXECUTE_NEXT;

  }

  talloc_const_free(to_free);

  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) {

    fr_slen_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)) {

      cf_log_err(cs, "arguments to 'case' statements MUST NOT be attribute references.");

      goto fail;

    }

    if (!tmpl_is_data(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)) {

      cf_log_err(cs, "String arguments to 'case' statements MUST be quoted.");

      goto fail;

    }

  } /* 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 its 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 fr_cmp_ret_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;

  fr_slen_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);

    fr_assert(xlat != NULL);

    /*

     *  Pure xlats are allowed, e.g. for %tolower(User-Name).

     */

    if (xlat->flags.constant) {

      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));

    goto do_cast;

  } 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;

    }

  do_cast:

    if (tmpl_cast_set(gext->vpt, type) < 0) {

      cf_log_perr(cs, "Failed setting cast type");

      goto error;

    }

  }

  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) != NULL) {

          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 {

      int insert_ret;

      insert_ret = fr_htrie_insert(gext->ht, single);

      if (unlikely(insert_ret < 0)) {

        cf_log_err(subci, "Failed inserting 'case' statement - %s", fr_strerror());

        goto error;

      }

      if (insert_ret > 0) {

        fr_htrie_find((void **)&single, gext->ht, single);

        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_t)(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",

    });

}