/* -*-C-*-

$Id: prmcrypt.c,v 1.10 2007/04/22 16:31:23 cph Exp $

Copyright (C) 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994,
    1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
    2006, 2007 Massachusetts Institute of Technology

This file is part of MIT/GNU Scheme.

MIT/GNU Scheme 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.

MIT/GNU Scheme 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 MIT/GNU Scheme; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301,
USA.

*/

/* Interface to mcrypt library */

#include "scheme.h"
#include "prims.h"
#include "usrdef.h"
#include "os.h"

/* If mcrypt.h unavailable, ignore it.  This helps
   "makegen/makegen.scm" work properly on systems lacking this
   library.  */
#ifdef HAVE_MCRYPT_H
#  include <mcrypt.h>
#endif

static SCHEME_OBJECT
cp2s (char * cp)
{
  if (cp == 0)
    return (SHARP_F);
  else
    {
      SCHEME_OBJECT s = (char_pointer_to_string (cp));
      mcrypt_free (cp);
      return (s);
    }
}

static size_t context_table_length = 0;
static MCRYPT * context_table = 0;

static size_t
search_context_table (MCRYPT context)
{
  size_t i;
  for (i = 0; (i < context_table_length); i += 1)
    if ((context_table[i]) == context)
      break;
  return (i);
}

static size_t
allocate_context_entry (void)
{
  size_t i = (search_context_table (0));
  if (i < context_table_length)
    return (i);
  if (i == 0)
    {
      context_table_length = 256;
      context_table
	= (OS_malloc ((sizeof (MCRYPT)) * context_table_length));
    }
  else
    {
      context_table_length *= 2;
      context_table
	= (OS_realloc (context_table,
		       ((sizeof (MCRYPT)) * context_table_length)));
    }
  {
    size_t j;
    for (j = i; (j < context_table_length); j += 1)
      (context_table[j]) = 0;
  }
  return (i);
}

static SCHEME_OBJECT
store_context (MCRYPT context)
{
  if (context == MCRYPT_FAILED)
    return (SHARP_F);
  {
    size_t i = (allocate_context_entry ());
    (context_table[i]) = context;
    return (ulong_to_integer (i));
  }
}

static void
forget_context (size_t index)
{
  (context_table[index]) = 0;
}

static size_t
arg_context_index (unsigned int arg)
{
  unsigned long n = (arg_ulong_index_integer (arg, context_table_length));
  if ((context_table[n]) == 0)
    error_bad_range_arg (arg);
  return (n);
}

static MCRYPT
arg_context (unsigned int arg)
{
  return (context_table [arg_context_index (arg)]);
}

DEFINE_PRIMITIVE ("MCRYPT_MODULE_OPEN", Prim_mcrypt_module_open, 2, 2, 0)
{
  PRIMITIVE_HEADER (2);
  PRIMITIVE_RETURN
    (store_context
     (mcrypt_module_open ((STRING_ARG (1)), 0, (STRING_ARG (2)), 0)));
}

DEFINE_PRIMITIVE ("MCRYPT_GENERIC_INIT", Prim_mcrypt_generic_init, 3, 3, 0)
{
  PRIMITIVE_HEADER (3);
  CHECK_ARG (2, STRING_P);
  PRIMITIVE_RETURN
    (long_to_integer
     (mcrypt_generic_init ((arg_context (1)),
			   (STRING_POINTER (ARG_REF (2))),
			   (STRING_LENGTH (ARG_REF (2))),
			   (STRING_ARG (3)))));
}

DEFINE_PRIMITIVE ("MCRYPT_GENERIC", Prim_mcrypt_generic, 4, 4, 0)
{
  PRIMITIVE_HEADER (4);
  CHECK_ARG (2, STRING_P);
  {
    SCHEME_OBJECT string = (ARG_REF (2));
    unsigned long l = (STRING_LENGTH (string));
    unsigned long start = (arg_ulong_index_integer (3, l));
    unsigned long end = (arg_integer_in_range (4, start, (l + 1)));
    PRIMITIVE_RETURN
      (long_to_integer
       (mcrypt_generic ((arg_context (1)),
			(STRING_LOC (string, start)),
			(end - start))));
  }
}

DEFINE_PRIMITIVE ("MDECRYPT_GENERIC", Prim_mdecrypt_generic, 4, 4, 0)
{
  PRIMITIVE_HEADER (4);
  CHECK_ARG (2, STRING_P);
  {
    SCHEME_OBJECT string = (ARG_REF (2));
    unsigned long l = (STRING_LENGTH (string));
    unsigned long start = (arg_ulong_index_integer (3, l));
    unsigned long end = (arg_integer_in_range (4, start, (l + 1)));
    PRIMITIVE_RETURN
      (long_to_integer
       (mdecrypt_generic ((arg_context (1)),
			  (STRING_LOC (string, start)),
			  (end - start))));
  }
}

DEFINE_PRIMITIVE ("MCRYPT_GENERIC_END", Prim_mcrypt_generic_end, 1, 1, 0)
{
  PRIMITIVE_HEADER (1);
  {
    size_t index = (arg_context_index (1));
    int result = (mcrypt_generic_end (context_table[index]));
    forget_context (index);
    PRIMITIVE_RETURN (long_to_integer (result));
  }
}

#define CONTEXT_OPERATION(name, cvt_val)				\
{									\
  PRIMITIVE_HEADER (1);							\
  PRIMITIVE_RETURN (cvt_val (name (arg_context (1))));			\
}

DEFINE_PRIMITIVE ("MCRYPT_ENC_SELF_TEST", Prim_mcrypt_enc_self_test, 1, 1, 0)
  CONTEXT_OPERATION (mcrypt_enc_self_test, long_to_integer)

DEFINE_PRIMITIVE ("MCRYPT_ENC_IS_BLOCK_ALGORITHM_MODE", Prim_mcrypt_enc_is_block_algorithm_mode, 1, 1, 0)
  CONTEXT_OPERATION (mcrypt_enc_is_block_algorithm_mode, BOOLEAN_TO_OBJECT)

DEFINE_PRIMITIVE ("MCRYPT_ENC_IS_BLOCK_ALGORITHM", Prim_mcrypt_enc_is_block_algorithm, 1, 1, 0)
  CONTEXT_OPERATION (mcrypt_enc_is_block_algorithm, BOOLEAN_TO_OBJECT)

DEFINE_PRIMITIVE ("MCRYPT_ENC_IS_BLOCK_MODE", Prim_mcrypt_enc_is_block_mode, 1, 1, 0)
  CONTEXT_OPERATION (mcrypt_enc_is_block_mode, BOOLEAN_TO_OBJECT)

DEFINE_PRIMITIVE ("MCRYPT_ENC_GET_KEY_SIZE", Prim_mcrypt_enc_get_key_size, 1, 1, 0)
  CONTEXT_OPERATION (mcrypt_enc_get_key_size, long_to_integer)

DEFINE_PRIMITIVE ("MCRYPT_ENC_GET_IV_SIZE", Prim_mcrypt_enc_get_iv_size, 1, 1, 0)
  CONTEXT_OPERATION (mcrypt_enc_get_iv_size, long_to_integer)

DEFINE_PRIMITIVE ("MCRYPT_ENC_GET_ALGORITHMS_NAME", Prim_mcrypt_enc_get_algorithms_name, 1, 1, 0)
  CONTEXT_OPERATION (mcrypt_enc_get_algorithms_name, cp2s)

DEFINE_PRIMITIVE ("MCRYPT_ENC_GET_MODES_NAME", Prim_mcrypt_enc_get_modes_name, 1, 1, 0)
  CONTEXT_OPERATION (mcrypt_enc_get_modes_name, cp2s)

#define MODULE_OPERATION(name, cvt_val)					\
{									\
  PRIMITIVE_HEADER (1);							\
  PRIMITIVE_RETURN (cvt_val (name ((STRING_ARG (1)), 0)));		\
}

DEFINE_PRIMITIVE ("MCRYPT_MODULE_SELF_TEST", Prim_mcrypt_module_self_test, 1, 1, 0)
  MODULE_OPERATION (mcrypt_module_self_test, long_to_integer)

DEFINE_PRIMITIVE ("MCRYPT_MODULE_IS_BLOCK_ALGORITHM_MODE", Prim_mcrypt_module_is_block_algorithm_mode, 1, 1, 0)
  MODULE_OPERATION (mcrypt_module_is_block_algorithm_mode, BOOLEAN_TO_OBJECT)

DEFINE_PRIMITIVE ("MCRYPT_MODULE_IS_BLOCK_ALGORITHM", Prim_mcrypt_module_is_block_algorithm, 1, 1, 0)
  MODULE_OPERATION (mcrypt_module_is_block_algorithm, BOOLEAN_TO_OBJECT)

DEFINE_PRIMITIVE ("MCRYPT_MODULE_IS_BLOCK_MODE", Prim_mcrypt_module_is_block_mode, 1, 1, 0)
  MODULE_OPERATION (mcrypt_module_is_block_mode, BOOLEAN_TO_OBJECT)

DEFINE_PRIMITIVE ("MCRYPT_MODULE_GET_ALGO_BLOCK_SIZE", Prim_mcrypt_module_get_algo_block_size, 1, 1, 0)
  MODULE_OPERATION (mcrypt_module_get_algo_block_size, long_to_integer)

DEFINE_PRIMITIVE ("MCRYPT_MODULE_GET_ALGO_KEY_SIZE", Prim_mcrypt_module_get_algo_key_size, 1, 1, 0)
  MODULE_OPERATION (mcrypt_module_get_algo_key_size, long_to_integer)

struct deallocate_list_arg
{
  char ** elements;
  int n_elements;
};

static void
deallocate_list (void * environment)
{
  struct deallocate_list_arg * a = environment;
  if ((a -> elements) != 0)
    mcrypt_free_p ((a -> elements), (a -> n_elements));
}

#define LIST_ITEMS(name)						\
{									\
  PRIMITIVE_HEADER (0);							\
  {									\
    struct deallocate_list_arg a;					\
    (a . elements) = (name (0, (& (a . n_elements))));			\
    transaction_begin ();						\
    transaction_record_action (tat_always, deallocate_list, (&a));	\
    if ((a . n_elements) < 0)						\
      error_external_return ();						\
    {									\
      char ** scan = (a . elements);					\
      char ** end = (scan + (a . n_elements));				\
      SCHEME_OBJECT sa = (make_vector ((a . n_elements), SHARP_F, 1));	\
      SCHEME_OBJECT * scan_sa = (VECTOR_LOC (sa, 0));			\
      while (scan < end)						\
	(*scan_sa++) = (char_pointer_to_string (*scan++));		\
      transaction_commit ();						\
      PRIMITIVE_RETURN (sa);						\
    }									\
  }									\
}

DEFINE_PRIMITIVE ("MCRYPT_LIST_ALGORITHMS", Prim_mcrypt_list_algorithms, 0, 0, 0)
  LIST_ITEMS (mcrypt_list_algorithms)

DEFINE_PRIMITIVE ("MCRYPT_LIST_MODES", Prim_mcrypt_list_modes, 0, 0, 0)
  LIST_ITEMS (mcrypt_list_modes)

static void
deallocate_key_sizes (void * environment)
{
  if (environment != 0)
    mcrypt_free (environment);
}

static SCHEME_OBJECT
convert_key_sizes (int * sizes, int n_sizes)
{
  transaction_begin ();
  transaction_record_action (tat_always, deallocate_key_sizes, sizes);
  if (n_sizes < 0)
    error_external_return ();
  if (n_sizes == 0)
    {
      transaction_commit ();
      return (SHARP_F);
    }
  {
    SCHEME_OBJECT sa = (make_vector (n_sizes, FIXNUM_ZERO, 1));
    SCHEME_OBJECT * scan_sa = (VECTOR_LOC (sa, 0));
    int * scan = sizes;
    int * end = (scan + n_sizes);
    while (scan < end)
      (*scan_sa++) = (long_to_integer (*scan++));
    transaction_commit ();
    return (sa);
  }
}

DEFINE_PRIMITIVE ("MCRYPT_ENC_GET_SUPPORTED_KEY_SIZES", Prim_mcrypt_enc_get_supported_key_sizes, 1, 1, 0)
{
  PRIMITIVE_HEADER (1);
  {
    int n_sizes;
    int * sizes
      = (mcrypt_enc_get_supported_key_sizes ((arg_context (1)), (&n_sizes)));
    PRIMITIVE_RETURN (convert_key_sizes (sizes, n_sizes));
  }
}

DEFINE_PRIMITIVE ("MCRYPT_MODULE_GET_ALGO_SUPPORTED_KEY_SIZES", Prim_mcrypt_module_get_algo_supported_key_sizes, 1, 1, 0)
{
  PRIMITIVE_HEADER (1);
  {
    int n_sizes;
    int * sizes
      = (mcrypt_module_get_algo_supported_key_sizes
	 ((STRING_ARG (1)), 0, (&n_sizes)));
    PRIMITIVE_RETURN (convert_key_sizes (sizes, n_sizes));
  }
}

#ifdef COMPILE_AS_MODULE

char *
dload_initialize_file (void)
{
  declare_primitive
    ("MCRYPT_MODULE_OPEN", Prim_mcrypt_module_open, 2, 2, 0);
  declare_primitive
    ("MCRYPT_GENERIC_INIT", Prim_mcrypt_generic_init, 3, 3, 0);
  declare_primitive
    ("MCRYPT_GENERIC", Prim_mcrypt_generic, 4, 4, 0);
  declare_primitive
    ("MDECRYPT_GENERIC", Prim_mdecrypt_generic, 4, 4, 0);
  declare_primitive
    ("MCRYPT_GENERIC_END", Prim_mcrypt_generic_end, 1, 1, 0);
  declare_primitive
    ("MCRYPT_ENC_SELF_TEST", Prim_mcrypt_enc_self_test, 1, 1, 0);
  declare_primitive
    ("MCRYPT_ENC_IS_BLOCK_ALGORITHM_MODE", Prim_mcrypt_enc_is_block_algorithm_mode, 1, 1, 0);
  declare_primitive
    ("MCRYPT_ENC_IS_BLOCK_ALGORITHM", Prim_mcrypt_enc_is_block_algorithm, 1, 1, 0);
  declare_primitive
    ("MCRYPT_ENC_IS_BLOCK_MODE", Prim_mcrypt_enc_is_block_mode, 1, 1, 0);
  declare_primitive
    ("MCRYPT_ENC_GET_KEY_SIZE", Prim_mcrypt_enc_get_key_size, 1, 1, 0);
  declare_primitive
    ("MCRYPT_ENC_GET_IV_SIZE", Prim_mcrypt_enc_get_iv_size, 1, 1, 0);
  declare_primitive
    ("MCRYPT_ENC_GET_ALGORITHMS_NAME", Prim_mcrypt_enc_get_algorithms_name, 1, 1, 0);
  declare_primitive
    ("MCRYPT_ENC_GET_MODES_NAME", Prim_mcrypt_enc_get_modes_name, 1, 1, 0);
  declare_primitive
    ("MCRYPT_MODULE_SELF_TEST", Prim_mcrypt_module_self_test, 1, 1, 0);
  declare_primitive
    ("MCRYPT_MODULE_IS_BLOCK_ALGORITHM_MODE", Prim_mcrypt_module_is_block_algorithm_mode, 1, 1, 0);
  declare_primitive
    ("MCRYPT_MODULE_IS_BLOCK_ALGORITHM", Prim_mcrypt_module_is_block_algorithm, 1, 1, 0);
  declare_primitive
    ("MCRYPT_MODULE_IS_BLOCK_MODE", Prim_mcrypt_module_is_block_mode, 1, 1, 0);
  declare_primitive
    ("MCRYPT_MODULE_GET_ALGO_BLOCK_SIZE", Prim_mcrypt_module_get_algo_block_size, 1, 1, 0);
  declare_primitive
    ("MCRYPT_MODULE_GET_ALGO_KEY_SIZE", Prim_mcrypt_module_get_algo_key_size, 1, 1, 0);
  declare_primitive
    ("MCRYPT_LIST_ALGORITHMS", Prim_mcrypt_list_algorithms, 0, 0, 0);
  declare_primitive
    ("MCRYPT_LIST_MODES", Prim_mcrypt_list_modes, 0, 0, 0);
  declare_primitive
    ("MCRYPT_ENC_GET_SUPPORTED_KEY_SIZES", Prim_mcrypt_enc_get_supported_key_sizes, 1, 1, 0);
  declare_primitive
     ("MCRYPT_MODULE_GET_ALGO_SUPPORTED_KEY_SIZES", Prim_mcrypt_module_get_algo_supported_key_sizes, 1, 1, 0);
  return "#prmcrypt";
}

#endif /* COMPILE_AS_MODULE */
