nasl_tree.c

/* SPDX-FileCopyrightText: 2023 Greenbone AG
 * SPDX-FileCopyrightText: 2002-2004 Tenable Network Security
 *
 * SPDX-License-Identifier: GPL-2.0-only
 */

#include "nasl_tree.h"

#include "exec.h"
#include "nasl_debug.h"
#include "nasl_func.h"
#include "nasl_global_ctxt.h"
#include "nasl_lex_ctxt.h"
#include "nasl_var.h"

#include <glib.h> /* for g_free */
#include <regex.h>
#include <stdlib.h> /* for abort */
#include <string.h> /* for memcpy */

static tree_cell *
alloc_tree_cell ()
{
  return g_malloc0 (sizeof (tree_cell));
}

tree_cell *
alloc_typed_cell (int typ)
{
  tree_cell *c = alloc_tree_cell ();
  c->type = typ;
  return c;
}

tree_cell *
alloc_RE_cell (int lnb, int t, tree_cell *l, char *re_str, int *err_c)
{
  regex_t *re = g_malloc0 (sizeof (regex_t));
  int e;

  tree_cell *c = alloc_tree_cell ();
  c->line_nb = lnb;
  c->type = t; /* We could check the type... */
  c->link[0] = l;
  c->link[1] = FAKE_CELL;
  e = regcomp (re, re_str, REG_EXTENDED | REG_NOSUB | REG_ICASE);
  if (!e)
    c->x.ref_val = re;
  else
    {
      char errbuf[100];
      regerror (e, re, errbuf, sizeof (errbuf));
      nasl_perror (NULL, "Line %d: Cannot compile regex: %s (error %d: %s)\n",
                   lnb, re_str, e, errbuf);
      g_free (re);
      *err_c = *err_c + 1;
    }
  g_free (re_str);
  return c;
}

tree_cell *
alloc_expr_cell (int lnb, int t, tree_cell *l, tree_cell *r)
{
  tree_cell *c = alloc_tree_cell ();
  c->line_nb = lnb;
  c->type = t;
  c->link[0] = l;
  c->link[1] = r;

  return c;
}

tree_cell *
dup_cell (const tree_cell *tc)
{
  tree_cell *r;
  int i;

  if (tc == NULL)
    return NULL;
  else if (tc == FAKE_CELL)
    return FAKE_CELL;

  r = alloc_tree_cell ();
  r->line_nb = tc->line_nb;
  r->type = tc->type;
  r->size = tc->size;

  switch (tc->type)
    {
    case CONST_STR:
    case CONST_DATA:
      r->x.str_val = g_malloc0 (tc->size + 1);
      memcpy (r->x.str_val, tc->x.str_val, tc->size);
      break;
    default:
      r->x = tc->x;
      break;
    }

  for (i = 0; i < 4; i++)
    r->link[i] = dup_cell (tc->link[i]);
  return r;
}

static void
free_tree (tree_cell *c)
{
  int i;
  nasl_array *a;

  if (c == NULL || c == FAKE_CELL)
    return;
  for (i = 0; i < 4; i++)
    if (c->link[i] != NULL)
      deref_cell (c->link[i]);

  if (c->x.str_val != NULL)
    switch (c->type)
      {
      case CONST_STR:
      case CONST_DATA:
#ifdef SCRATCH_FREED_MEMORY
        if (c->size > 0)
          memset (c->x.str_val, 0xFF, c->size);
#endif
        g_free (c->x.str_val);
        break;

      case CONST_REGEX:
      case COMP_RE_MATCH:
      case COMP_RE_NOMATCH:
        if (c->x.ref_val != NULL)
          {
            regfree (c->x.ref_val);
            g_free (c->x.ref_val);
          }
        break;

      case DYN_ARRAY:
        a = c->x.ref_val;
        if (a != NULL)
          {
            free_array (a);
            g_free (c->x.ref_val);
          }
        break;

      case NODE_FUN_DEF:
      case NODE_FUN_CALL:
      case NODE_VAR:
      case NODE_DECL:
      case NODE_ARG:
      case NODE_ARRAY_EL:
      case NODE_FOREACH:
        g_free (c->x.str_val);
        break;
      }
#ifdef SCRATCH_FREED_MEMORY
  memset (c, 0xFF, sizeof (*c));
#endif
  g_free (c);
}

void
ref_cell (tree_cell *c)
{
  if (c == NULL || c == FAKE_CELL)
    return;
  c->ref_count++;
  if (c->ref_count < 0)
    {
      nasl_perror (NULL, "ref_cell: ref count is negative!\n");
      nasl_dump_tree (c);
      abort ();
    }
}

void
deref_cell (tree_cell *c)
{
  if (c == NULL || c == FAKE_CELL)
    return;
  if (--c->ref_count < 0)
    free_tree (c);
}

/* Debug */

static char *node_names[] = {
  "NODE_EMPTY",      "NODE_IF_ELSE",    "NODE_INSTR_L",      "NODE_FOR",
  "NODE_WHILE",      "NODE_FOREACH",    "NODE_REPEAT_UNTIL", "NODE_REPEATED",
  "NODE_FUN_DEF",    "NODE_FUN_CALL",   "NODE_DECL",         "NODE_ARG",
  "NODE_RETURN",     "NODE_BREAK",      "NODE_CONTINUE",

  "NODE_ARRAY_EL",   "NODE_AFF",        "NODE_VAR",          "NODE_LOCAL",
  "NODE_GLOBAL",     "NODE_PLUS_EQ",    "NODE_MINUS_EQ",     "NODE_MULT_EQ",
  "NODE_DIV_EQ",     "NODE_MODULO_EQ",

  "NODE_L_SHIFT_EQ", "NODE_R_SHIFT_EQ", "NODE_R_USHIFT_EQ",  "EXPR_AND",
  "EXPR_OR",         "EXPR_NOT",

  "EXPR_PLUS",       "EXPR_MINUS",      "EXPR_U_MINUS",      "EXPR_MULT",
  "EXPR_DIV",        "EXPR_MODULO",     "EXPR_EXPO",

  "EXPR_BIT_AND",    "EXPR_BIT_OR",     "EXPR_BIT_XOR",      "EXPR_BIT_NOT",
  "EXPR_INCR",       "EXPR_DECR",       "EXPR_L_SHIFT",      "EXPR_R_SHIFT",
  "EXPR_R_USHIFT",

  "COMP_MATCH",      "COMP_NOMATCH",    "COMP_RE_MATCH",     "COMP_RE_NOMATCH",

  "COMP_LT",         "COMP_LE",         "COMP_EQ",           "COMP_NE",
  "COMP_GT",         "COMP_GE",         "CONST_INT",         "CONST_STR",
  "CONST_DATA",      "CONST_REGEX",

  "ARRAY_ELEM",

  "REF_VAR",         "REF_ARRAY",       "DYN_ARRAY"};

static void
prefix (int n, int i)
{
  int j;
  for (j = 0; j < n; j++)
    putchar (' ');
  if (i <= 0)
    fputs ("   ", stdout);
  else
    printf ("%d: ", i);
}

char *
dump_cell_val (const tree_cell *c)
{
  static char txt[80];

  if (c == NULL)
    return "NULL";
  else if (c == FAKE_CELL)
    return "FAKE";
  else
    switch (c->type)
      {
      case CONST_INT:
        snprintf (txt, sizeof (txt), "%ld", c->x.i_val);
        break;
      case CONST_STR:
      case CONST_DATA: /* Beurk (English: Yuck) */
        if ((unsigned int) c->size >= sizeof (txt) + 2)
          {
            snprintf (txt, sizeof (txt), "\"%s", c->x.str_val);
            strcpy (txt + (sizeof (txt) - 5), "...\"");
          }
        else
          snprintf (txt, sizeof (txt), "\"%s\"", c->x.str_val);
        break;
      default:
        snprintf (txt, sizeof (txt), "???? (%s)", nasl_type_name (c->type));
        break;
      }
  return txt;
}

static void
dump_tree (const tree_cell *c, int n, int idx)
{
  int i;

  if (c == NULL)
    return;

  prefix (n, idx);

  if (c == FAKE_CELL)
    {
      puts ("* FAKE *");
      return;
    }

  if (c->line_nb > 0)
    printf ("L%d: ", c->line_nb);

  if (c->type < 0
      || (unsigned int) c->type >= sizeof (node_names) / sizeof (node_names[0]))
    printf ("* UNKNOWN %d (0x%x)*\n", c->type, c->type);
  else
    printf ("%s (%d)\n", node_names[c->type], c->type);

  prefix (n, idx);
  printf ("Ref_count=%d", c->ref_count);
  if (c->size > 0)
    {
      /*prefix(n, idx); */
      printf ("\tSize=%d (0x%x)", c->size, c->size);
    }
  putchar ('\n');

  switch (c->type)
    {
    case CONST_INT:
      prefix (n, 0);
      printf ("Val=%ld\n", c->x.i_val);
      break;

    case CONST_STR:
    case CONST_DATA:
    case NODE_VAR:
    case NODE_FUN_DEF:
    case NODE_FUN_CALL:
    case NODE_DECL:
    case NODE_ARG:
    case NODE_ARRAY_EL:
    case ARRAY_ELEM:
      prefix (n, 0);
      if (c->x.str_val == NULL)
        printf ("Val=(null)\n");
      else
        printf ("Val=\"%s\"\n", c->x.str_val);
      break;
    case REF_VAR:
      prefix (n, 0);
      if (c->x.ref_val == NULL)
        printf ("Ref=(null)\n");
      else
        {
          named_nasl_var *v = c->x.ref_val;
          printf ("Ref=(type=%d, name=%s, value=%s)\n", v->u.var_type,
                  v->var_name != NULL ? v->var_name : "(null)",
                  var2str (&v->u));
        }
      break;

    case REF_ARRAY:
    case DYN_ARRAY:
      break;
    }

  for (i = 0; i < 4; i++)
    {
      dump_tree (c->link[i], n + 3, i + 1);
    }
}

const char *
nasl_type_name (int t)
{
  static char txt4[4][32]; /*  This function may be called 4 times in the same
                              expression */
  static int i = 0;
  char *txt;

  if (i >= 4)
    i = 0;
  txt = txt4[i];

  if (t >= 0 && (unsigned int) t < sizeof (node_names) / sizeof (node_names[0]))
    snprintf (txt, 32, "%s (%d)", node_names[t], t);
  else
    snprintf (txt, 32, "*UNKNOWN* (%d)", t);
  i++;
  return txt;
}

void
nasl_dump_tree (const tree_cell *c)
{
  printf ("^^^^ %p ^^^^^\n", (void *) c);
  if (c == NULL)
    puts ("NULL CELL");
  else if (c == FAKE_CELL)
    puts ("FAKE CELL");
  else
    dump_tree (c, 0, 0);
  printf ("vvvvvvvvvvvvvvvvvv\n");
}

char *
get_line_nb (const tree_cell *c)
{
  static char txt[32];
  if (c == NULL || c == FAKE_CELL || c->line_nb <= 0)
    return "";
  snprintf (txt, sizeof (txt), " at or near line %d ", c->line_nb);
  return txt;
}

int
nasl_is_leaf (const tree_cell *pc)
{
  if (pc == NULL || pc == FAKE_CELL)
    return 1;
  switch (pc->type)
    {
    case CONST_INT:
    case CONST_STR:
    case CONST_DATA:
    case REF_ARRAY:
    case DYN_ARRAY:
      return 1;
    default:
      return 0;
    }
 /*NOTREACHED*/}

 int
 cell_type (const tree_cell *c)
 {
   if (c == NULL || c == FAKE_CELL)
     return 0;
   else
     return c->type;
 }