nasl_func.c

大国补丁后的nessus2.2.8的源代码

/* Nessus Attack Scripting Language 
 *
 * Copyright (C) 2002 - 2004 Tenable Network Security
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2,
 * as published by the Free Software Foundation
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */
#include <includes.h>

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

#include "nasl_debug.h"



static int
hash_str(const char* s)
{
  return hash_str2(s, FUNC_NAME_HASH);
}

/* This function climbs up in the context list */
static nasl_func*
get_func(lex_ctxt* ctxt, const char* name, int h)
{
  nasl_func	*v, *prev;
  lex_ctxt	*c;

  for (c = ctxt; c != NULL; c = c->up_ctxt)
    {
      for (prev = NULL, v = c->functions[h]; v != NULL; v = v->next_func)
	if (v->func_name != NULL && strcmp(name, v->func_name) == 0)
	  {
#ifdef SILLY_OPT
	    if (prev != NULL) /* Move it to start of list */
	      {
		prev->next_func = v->next_func;
		v->next_func = c->functions[h];
		c->functions[h]= v;
	      }
#endif
	  return v;
	  }
#ifdef SILLY_OPT
	else
	  prev = v;
#endif
    }

  return NULL;
}

nasl_func*
insert_nasl_func(lex_ctxt* lexic, const char* fname, tree_cell* decl_node)
{
  int		h = hash_str(fname);
  int		i;
  nasl_func	*pf;
  tree_cell	*pc;

  if (get_func(lexic, fname, h) != NULL)
    {
      nasl_perror(lexic, "insert_nasl_func: function '%s' is already defined\n",
	      fname);
      return NULL;
    }
  pf = emalloc(sizeof(nasl_func));
  pf->func_name = estrdup(fname);

  if (decl_node != NULL && decl_node != FAKE_CELL)
    {
      for (pc = decl_node->link[0]; pc != NULL; pc = pc->link[0])
	if (pc->x.str_val == NULL)
	  pf->nb_unnamed_args ++;
	else
	  pf->nb_named_args ++;

      pf->args_names = emalloc(sizeof(char*) * pf->nb_named_args);
      for (i = 0, pc = decl_node->link[0]; pc != NULL; pc = pc->link[0])
	if (pc->x.str_val != NULL)
	  pf->args_names[i ++] = estrdup(pc->x.str_val);
      /* sort arg names */
      qsort(pf->args_names, pf->nb_named_args, 
	    sizeof(pf->args_names[0]), strcmp);

      pf->block = decl_node->link[1];
      ref_cell(pf->block);
    }
  /* Allow variable number of arguments for user defined functions */
  if (decl_node != NULL)
    pf->nb_unnamed_args = 9999;

  pf->next_func = lexic->functions[h];
  lexic->functions[h] = pf;
  return pf;
}

tree_cell*
decl_nasl_func(lex_ctxt* lexic, tree_cell* decl_node)
{
  if (decl_node == NULL || decl_node == FAKE_CELL)
    {
      nasl_perror(lexic, "Cannot insert NULL or FAKE cell as function\n");
      return NULL;
    }
    
  if (insert_nasl_func(lexic, decl_node->x.str_val, decl_node) == NULL)
    return NULL;
  else
    return FAKE_CELL;
}

nasl_func*
get_func_ref_by_name(lex_ctxt* ctxt, const char* name)
{
  int		h = hash_str(name);
  nasl_func	*f;


  if ((f = get_func(ctxt, name, h)) != NULL)
    return f;
  else
    return NULL;
}

static int
stringcompare(const void * a,  const void * b)
{
  char ** s1 = (char**)a, ** s2 = (char**)b;
  return strcmp(*s1, *s2);
}

extern FILE*	nasl_trace_fp;

tree_cell*
nasl_func_call(lex_ctxt* lexic, const nasl_func* f, tree_cell* arg_list)
{
#if 0
  return FAKE_CELL;
#else
  int		nb_u = 0, nb_n = 0, nb_a = 0;
  tree_cell	*pc = NULL, *pc2 = NULL, *retc = NULL;
  lex_ctxt	*lexic2 = NULL;
  char		*trace_buf = NULL;
  int		trace_buf_len = 0, tn;
#define TRACE_BUF_SZ	255

#if 0
  nasl_dump_tree(arg_list);
#endif

  /* 1. Create a new context */
  lexic2 = init_empty_lex_ctxt();
  lexic2->script_infos = lexic->script_infos;
  lexic2->authenticated = lexic->authenticated;
  lexic2->recv_timeout = lexic->recv_timeout;
  lexic2->fct_ctxt = 1;

  if (nasl_trace_fp != NULL)
    {
      trace_buf = emalloc(TRACE_BUF_SZ);
      tn = 
	snprintf(trace_buf, TRACE_BUF_SZ, "Call %s(", f->func_name);
      if (tn > 0) trace_buf_len += tn;
    }

  if (! (f->flags & FUNC_FLAG_COMPAT))
    {
      for (pc = arg_list; pc != NULL; pc = pc->link[1])
	if (pc->x.str_val == NULL)
	  nb_u ++;
	else
	  {
	    size_t num = f->nb_named_args;
	    if (lfind(&pc->x.str_val, f->args_names, &num, sizeof(char*), stringcompare) != NULL)
	      nb_n ++;
	  }
  
      if (nb_n + nb_u > f->nb_unnamed_args + f->nb_named_args)
	nasl_perror(lexic,
		"Too many args for function '%s' [%dN+%dU > %dN+%dU]\n",
		f->func_name, nb_n, nb_u, f->nb_unnamed_args, f->nb_named_args);
      /*
       * I should look exactly how unnamed arguments works... 
       * Or maybe I should remove this feature?
       */

      for (nb_u = 0, pc = arg_list; pc != NULL; pc = pc->link[1])
	{
#if 0
	  pc2 = pc->link[0];
	  ref_cell(pc2);
	  do
	    {
	      pc22 = nasl_exec(lexic, pc2);
	      deref_cell(pc2);
	      pc2 = pc22;
	    }
	  while (! nasl_is_leaf(pc2));
#else
	  pc2 = cell2atom(lexic, pc->link[0]);
#endif
	  if (pc->x.str_val == NULL)
	    {
	      /* 2. Add unnamed (numbered) variables for unnamed args */
	      if (add_numbered_var_to_ctxt(lexic2, nb_u, pc2) == NULL)
		goto error;
	      nb_u ++;
	      if (nasl_trace_fp != NULL && trace_buf_len < TRACE_BUF_SZ)
		{
		  tn =
		    snprintf(trace_buf + trace_buf_len, 
			     TRACE_BUF_SZ - trace_buf_len,
			     "%s%d: %s",
			     nb_a > 0 ? ", " : "", nb_u, 
			     dump_cell_val(pc2));
		  if (tn > 0) trace_buf_len += tn;
		}
	      nb_a ++;
	    }
	  else
	    {
	      /* 3. and add named variables for named args */
	      if (add_named_var_to_ctxt(lexic2, pc->x.str_val, pc2) == NULL)
		goto error;
	      if (nasl_trace_fp != NULL && trace_buf_len < TRACE_BUF_SZ)
		{
		  tn =
		    snprintf(trace_buf + trace_buf_len,
			     TRACE_BUF_SZ - trace_buf_len,
			     "%s%s: %s",
			     nb_a > 0 ? ", " : "", pc->x.str_val,
			     dump_cell_val(pc2));
		  if (tn > 0) trace_buf_len += tn;
		}
	      nb_a ++;
	    }
	  deref_cell(pc2);
	}

      if (nasl_trace_fp != NULL)
	{
	  if (trace_buf_len < TRACE_BUF_SZ)
	    nasl_trace(lexic, "NASL> %s)\n", trace_buf);
	  else
	    nasl_trace(lexic, "NASL> %s ...)\n", trace_buf);
	  trace_buf_len = 0;
	  efree(&trace_buf);
	}

      /* 4. Chain new context to old (lexic) */
      lexic2->up_ctxt = lexic;
      /* 5. Execute */
      if (f->flags & FUNC_FLAG_INTERNAL)
	{
	  tree_cell*	(*pf2)(lex_ctxt*) = f->block;
	  retc = pf2(lexic2);
	}
      else
	{
	  retc = nasl_exec(lexic2, f->block);
	  deref_cell(retc);
	  retc = FAKE_CELL;
	}

      if ((retc == NULL || retc == FAKE_CELL) &&
	  (lexic2->ret_val != NULL && lexic2->ret_val != FAKE_CELL))
	{
#if 0
	  nasl_perror(lexic, "nasl_func_call: nasl_exec(%s) returns NULL or FAKE value, but context disagrees. Fixing...\n", f->func_name);
	  nasl_dump_tree(retc);
#endif
	  retc = lexic2->ret_val;
	  ref_cell(retc);
	}

        if(nasl_trace_enabled())nasl_trace(lexic, "NASL> Return %s: %s\n", f->func_name,
		  dump_cell_val(retc));
#if 1
      if (! nasl_is_leaf(retc))
	{
	  nasl_perror(lexic, "nasl_func_call: return value from %s is not atomic!\n", f->func_name);
	  nasl_dump_tree(retc);
	}
#endif

      free_lex_ctxt(lexic2); lexic2 = NULL;
      return retc;
    }


 error:
  free_lex_ctxt(lexic2);
  return NULL;
#endif
}

tree_cell* nasl_return(lex_ctxt* ctxt, tree_cell* retv)
{
  tree_cell	*c;

  retv = cell2atom(ctxt, retv);
  if (retv == NULL)
    retv = FAKE_CELL;
    
    

  if (retv != FAKE_CELL && retv->type == REF_ARRAY)
    /* We have to "copy" it as the referenced array will be freed */
    {
      c = copy_ref_array(retv);
      deref_cell(retv);
      retv = c;
    }

  while (ctxt != NULL)
    {
      ctxt->ret_val = retv;
      ref_cell(retv);
      if (ctxt->fct_ctxt)
	break;
      ctxt = ctxt->up_ctxt;
    }
  /* Bug? Do not return NULL, as we may test it to break the control flow */
  deref_cell(retv);
  return FAKE_CELL;
}

static void
free_func(nasl_func* f)
{
  int	i;

  efree(&f->func_name);
  if (! (f->flags & FUNC_FLAG_INTERNAL))
    {
      for (i = 0; i < f->nb_named_args; i ++)
	efree(f->args_names + i);
      efree(&f->func_name);
      efree(&f->args_names);
      deref_cell(f->block);
    }
  free(f);
}


void
free_func_chain(nasl_func* f)
{
  if (f == NULL)
    return;
  free_func_chain(f->next_func);
  free_func(f);
}