Coverity fixes from Nelson

[sxemacs] / src / effi.c

/*
 * effi.c --- Foreign Function Interface for SXEmacs.
 *
 * Copyright (C) 2004-2008 Zajcev Evgeny
 *
This file is part of SXEmacs

SXEmacs 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 3 of the License, or
(at your option) any later version.

SXEmacs 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, see <http://www.gnu.org/licenses/>. */


#include <config.h>
#include "lisp.h"

#include <dlfcn.h>
#include <math.h>
#include "sysdep.h"
#include "effi.h"

#include "buffer.h"
#ifdef FILE_CODING
#  include "mule/file-coding.h"
#endif

#ifdef HAVE_LIBFFI
#  undef ALIGN
#  include <ffi.h>
#endif  /* HAVE_LIBFFI */

#ifdef EF_USE_ASYNEQ
#  include "events/workers.h"
#  include "events/worker-asyneq.h"
#endif  /* EF_USE_ASYNEQ */

/* For `x-device-display' */
#include "ui/X11/console-x.h"
#include "ui/device.h"

#define EFFI_CODING     Qnative

/*
 * Some compatibility for XEmacs
 */
#ifdef SXEMACS
#  define SIGNAL_ERROR signal_error
#  define FFIBYTE Bufbyte
#  define WRITE_C_STRING(x,y) write_c_string((x),(y))
#  define LRECORD_DESCRIPTION lrecord_description
#else
#  define SIGNAL_ERROR Fsignal
#  define FFIBYTE Ibyte
#  define WRITE_C_STRING(x,y) write_c_string((y),(x))
#  define LRECORD_DESCRIPTION memory_description
#endif  /* SXEMACS */

/*
 * Built-in types:
 *   byte, ubyte, char, uchar,
 *   short, ushort, int, uint,
 *   long, ulong,
 *   float, double,
 *   void, pointer, c-string
 *
 * Function type:
 *
 *   (function RET-TYPE IN-TYPE .. IN-TYPE)
 *
 * Array types:
 *
 *   (array TYPE SIZE)
 *
 * Structures and unions types:
 * 
 *   (struct|union NAME
 *     (SLOT-NAME TYPE)
 *     (SLOT-NAME TYPE)
 *     ...
 *     (SLOT-NAME TYPE))
 *
 * Pointers:
 *
 *   pointer or (pointer TYPE)
 */

/* Foreign types */
Lisp_Object Q_byte, Q_unsigned_byte;
Lisp_Object Q_char, Q_unsigned_char;
Lisp_Object Q_short, Q_unsigned_short;
Lisp_Object Q_int, Q_unsigned_int;
Lisp_Object Q_long, Q_unsigned_long;
Lisp_Object Q_float, Q_double;
Lisp_Object Q_void;
Lisp_Object Q_array, Q_pointer;
Lisp_Object Q_union, Q_struct;
Lisp_Object Q_function;
Lisp_Object Q_c_string, Q_c_data;

#define FFI_POINTERP(type) (EQ(type, Q_pointer)                                \
                            || (CONSP(type) && EQ(XCAR(type), Q_pointer)))

#define FFI_TPTR(type) (EQ(type, Q_c_string)                                   \
                        || EQ(type, Q_c_data)                                  \
                        || FFI_POINTERP(type)                                  \
                        || (CONSP(type) && ((EQ(XCAR(type), Q_c_data))         \
                                            || EQ(XCAR(type), Q_array))))

Lisp_Object Qffiobjectp;
Lisp_Object Qffi_translate_to_foreign;
Lisp_Object Qffi_translate_from_foreign;

/* Alist with elements in form (NAME . TYPE) */
Lisp_Object Vffi_loaded_libraries;
Lisp_Object Vffi_named_types;

Lisp_Object Vffi_type_checker;

static Lisp_Object Vffi_all_objects;

Lisp_Object Q_ffi_callback;

static Lisp_Object
mark_ffiobject(Lisp_Object obj)
{
        Lisp_EffiObject *ffio = XEFFIO(obj);
        mark_object(ffio->type);
        mark_object(ffio->size);
        mark_object(ffio->plist);
        return (ffio->plist);
}

static void
print_ffiobject(Lisp_Object obj, Lisp_Object printcharfun, int escapeflag)
{
        /* This function can GC */
        Lisp_EffiObject *ffio = XEFFIO(obj);
        char buf[256];

        escapeflag = escapeflag;        /* shutup compiler */
        if (print_readably) {
#ifdef SXEMACS
                error("printing unreadable object #<ffiobject 0x%x>",
                      ffio->header.uid);
#else
                signal_ferror(Qinternal_error,
                              "printing unreadable object #<ffiobject 0x%x>",
                              ffio->header.uid);
#endif  /* SXEMACS */
        }
        WRITE_C_STRING("#<ffiobject ", printcharfun);
        /* Print FFIO type */
        if (!NILP(ffio->type)) {
                WRITE_C_STRING("type=", printcharfun);
                print_internal(ffio->type, printcharfun, 1);
                WRITE_C_STRING(" ", printcharfun);
        }
        snprintf(buf, 255, "size=%ld fotype=%d foptr=%p>",
                 (long)XINT(ffio->size), ffio->fotype, ffio->fop.generic);
        WRITE_C_STRING(buf, printcharfun);
}

static const struct LRECORD_DESCRIPTION ffiobject_description[] = {
        {XD_LISP_OBJECT, offsetof(Lisp_EffiObject, type)},
        {XD_LISP_OBJECT, offsetof(Lisp_EffiObject, size)},
        {XD_LISP_OBJECT, offsetof(Lisp_EffiObject, plist)},
        {XD_INT, offsetof(Lisp_EffiObject, fotype)},
        {XD_OPAQUE_PTR, offsetof(Lisp_EffiObject, fop)},
#ifdef SXEMACS
        {XD_SIZE_T, offsetof(Lisp_EffiObject, storage_size)},
#else
        {XD_ELEMCOUNT, offsetof(Lisp_EffiObject, storage_size)},
#endif  /* SXEMACS */
        {XD_END}
};

static Lisp_Object
ffi_getprop(Lisp_Object fo, Lisp_Object property)
{
        return external_plist_get(&XEFFIO(fo)->plist, property, 0, ERROR_ME);
}

static int
ffi_putprop(Lisp_Object fo, Lisp_Object property, Lisp_Object value)
{
        external_plist_put(&XEFFIO(fo)->plist, property, value, 0, ERROR_ME);
        return 1;
}

static int
ffi_remprop(Lisp_Object fo, Lisp_Object property)
{
        return external_remprop(&XEFFIO(fo)->plist, property, 0, ERROR_ME);
}

#ifdef SXEMACS
static size_t
sizeof_ffiobject(const void *header)
{
        const Lisp_EffiObject *effio = (const Lisp_EffiObject *)header;
        return (sizeof(Lisp_EffiObject) + effio->storage_size);
}
#else
static Bytecount
sizeof_ffiobject(const void *header)
{
        const Lisp_EffiObject *effio = (const Lisp_EffiObject *)header;
        return (sizeof(Lisp_EffiObject) + effio->storage_size);
}
#endif  /* SXEMACS */

/* Define ffiobject implementation */
const struct lrecord_implementation lrecord_ffiobject = {
        .name = "ffiobject",
        .marker = mark_ffiobject,
        .printer = print_ffiobject,
        .finalizer = 0,
        .equal = 0,
        .hash = 0,
        .description = ffiobject_description,
        .getprop = ffi_getprop,
        .putprop = ffi_putprop,
        .remprop = ffi_remprop,
        .plist = Fffi_plist,
        .static_size = 0,
        .size_in_bytes_method = sizeof_ffiobject,
        .lrecord_type_index = lrecord_type_ffiobject,
        .basic_p = 0
};

\f
/** alignment in union and structures **/
/*
 * x86:
 *
 *   - An entire structure or union is aligned on the same boundary as
 *     its most strictly aligned member.
 *
 *   - Each member is assigned to the lowest available offset with the
 *     appropriate alignment.  This may require /internal padding/,
 *     depending on the previous member.
 *
 *   - A structure's size is increased, if necessary, to make it a
 *     multiple of the alignment.  This may require /tail padding/,
 *     depending on the last member.
 *
 *  Internal padding:
 *
 *    struct {
 *     char c;            .-------2+---1+---0.
 *     short s;           |  s     |pad |  c |
 *    }                   `--------+----+----'
 *
 *  Internal and Tail padding:
 *
 *    struct {            .------------1+---0.
 *     char c;            |     pad     |  c |
 *     double d;          |-------------+---4|
 *     short s;           |         d        |
 *    }                   |-----------------8|
 *                        |         d        |
 *                        |------14+-------12|
 *                        |   pad  |    s    |
 *                        `--------+---------'
 *
 *  Union allocation:
 *
 *    union {             .------------1+---0.
 *     char c;            |     pad     |  c |
 *     short s;           |-------2+----+---0|
 *     int j;             |  pad   |    s    |
 *    }                   |--------+--------0|
 *                        |        j         |
 *                        `------------------'
 */
static Lisp_Object
ffi_check_type(Lisp_Object type)
{
        return apply1(Vffi_type_checker, Fcons(type, Fcons(Qt, Qnil)));
}

DEFUN("ffi-basic-type-p", Fffi_basic_type_p, 1, 1, 0, /*
Return non-nil if TYPE is a basic FFI type.

A type is said to be basic, if it is neither a pointer nor a
function, and there is a corresponding built-in type in C.
*/
      (type))
{
        if (EQ(type, Q_byte) || EQ(type, Q_unsigned_byte) || EQ(type, Q_char)
            || EQ(type, Q_unsigned_char) || EQ(type, Q_short)
            || EQ(type, Q_unsigned_short) || EQ(type, Q_int)
            || EQ(type, Q_unsigned_int) || EQ(type, Q_long)
            || EQ(type, Q_unsigned_long) || EQ(type, Q_float)
            || EQ(type, Q_double) || EQ(type, Q_void)
            || EQ(type, Q_c_string) || EQ(type, Q_c_data)
            || (CONSP(type) && EQ(XCAR(type), Q_c_data)))
                return Qt;
        else
                return Qnil;
}


static Lisp_Object
ffi_canonicalise_type(Lisp_Object type)
{
/* this function canNOT GC */

        while (!NILP(type) && NILP(Fffi_basic_type_p(type)) && SYMBOLP(type)) {
                if EQ(type, Q_pointer)
                        break;
                type = Fcdr(Fassq(type, Vffi_named_types));
        }

        return type;
}

DEFUN("ffi-canonicalise-type", Fffi_canonicalise_type, 1, 1, 0, /*
Return FFI type TYPE in a canonical form.
*/
      (type))
{
        Lisp_Object canon_type = ffi_canonicalise_type(type);
        if (NILP(canon_type)) {
#ifdef SXEMACS
                signal_simple_error("No such FFI type", type);
#else
                signal_error(Qinternal_error, "No such FFI type", type);
#endif  /* SXEMACS */
        }
        return canon_type;
}

DEFUN("ffi-size-of-type", Fffi_size_of_type, 1, 1, 0,   /*
Return the size of the foreign type TYPE.

Valid foreign types are: `byte', `unsigned-byte', `char',
`unsigned-char', `short', `unsigned-short', `int', `unsigned-int',
`long', `unsigned-long', `pointer', `float', `double', 
`object', and `c-string'.
*/
      (type))
{
        int tsize;

        type = ffi_canonicalise_type(type);
        if (EQ(type, Q_void))
                tsize = 0;
        else if (EQ(type, Q_byte))
                tsize = sizeof(int8_t);
        else if (EQ(type, Q_unsigned_byte))
                tsize = sizeof(uint8_t);
        else if (EQ(type, Q_char))
                tsize = sizeof(char);
        else if (EQ(type, Q_unsigned_char))
                tsize = sizeof(unsigned char);
        else if (EQ(type, Q_short))
                tsize = sizeof(short);
        else if (EQ(type, Q_unsigned_short))
                tsize = sizeof(unsigned short);
        else if (EQ(type, Q_int))
                tsize = sizeof(int);
        else if (EQ(type, Q_unsigned_int))
                tsize = sizeof(unsigned int);
        else if (EQ(type, Q_long))
                tsize = sizeof(long);
        else if (EQ(type, Q_unsigned_long))
                tsize = sizeof(unsigned long);
        else if (EQ(type, Q_float))
                tsize = sizeof(float);
        else if (EQ(type, Q_double))
                tsize = sizeof(double);
        else if (EQ(type, Q_c_string))
                tsize = sizeof(char *);
        else if (FFI_POINTERP(type))
                tsize = sizeof(void *);
        else if (EQ(type, Q_c_data))
                tsize = sizeof(void *);
        else if (CONSP(type) && EQ(XCAR(type), Q_c_data)) {
                Lisp_Object cdsize = XCDR(type);
                CHECK_INT(cdsize);
                tsize = XINT(cdsize);
        } else if (CONSP(type) && EQ(XCAR(type), Q_function))
                tsize = sizeof(void(*));
        else if (CONSP(type) && EQ(XCAR(type), Q_array)) {
                Lisp_Object atype = Fcar(XCDR(type));
                Lisp_Object asize = Fcar(Fcdr(XCDR(type)));

                CHECK_INT(asize);
                tsize = XINT(asize) * XINT(Fffi_size_of_type(atype));
        } else if (CONSP(type) && EQ(XCAR(type), Q_struct)) {
                return Fffi_slot_offset(type, Qnil);
        } else if (CONSP(type) && EQ(XCAR(type), Q_union)) {
                Lisp_Object slots = Fcdr(XCDR(type));

                CHECK_CONS(slots);

                tsize = 0;
                while (!NILP(slots)) {
                        Lisp_Object slot_type = Fcar(Fcdr(XCAR(slots)));
                        int slot_size = XINT(Fffi_size_of_type(slot_type));
                        if (slot_size > tsize)
                                tsize = slot_size;
                        slots = XCDR(slots);
                }
        } else {
#ifdef SXEMACS
                signal_simple_error("Unrecognized foreign type", type);
#else
                signal_error(Qinternal_error, "Unrecognized foreign type", type);
#endif  /* SXEMACS */
        }

        return make_int(tsize);
}

DEFUN("make-ffi-object", Fmake_ffi_object, 1, 2, 0, /*
Create a new FFI object of type TYPE.
If optional argument SIZE is non-nil it should be an
integer, in this case additional storage size to hold data 
of at least length SIZE is allocated.
*/
      (type, size))
{
        int cs_or_cd;
        Lisp_Object ctype;
        Lisp_Object result = Qnil;
        Lisp_EffiObject *ffio;
        struct gcpro gcpro1;

        GCPRO1(result);

        /* NOTE: ffi_check_type returns canonical type */
        ctype = ffi_check_type(type);
        if (NILP(size))
                size = Fffi_size_of_type(type);
        CHECK_INT(size);

        if (CONSP(ctype) && EQ(XCAR(ctype), Q_c_data) && INTP(XCDR(ctype)))
                size = XCDR(type);

        cs_or_cd = EQ(ctype, Q_c_string) || (EQ(ctype, Q_c_data));
        if ((cs_or_cd && (XINT(size) < 1))
            || (!(cs_or_cd || FFI_POINTERP(ctype))
                && (XINT(size) < XINT(Fffi_size_of_type(type)))))
#ifdef SXEMACS
                signal_simple_error("storage size too small to store type",
                                    list2(size, type));

        ffio = alloc_lcrecord(sizeof(Lisp_EffiObject)+XINT(size),
                              &lrecord_ffiobject);
        XSETEFFIO(result, ffio);
#else
                signal_error(Qinternal_error,
                             "storage size too small to store type",
                             list2(size, type));

        ffio = old_basic_alloc_lcrecord(sizeof(Lisp_EffiObject)+XINT(size),
                                        &lrecord_ffiobject);
        result = wrap_effio(ffio);
#endif  /* SXEMACS */

        ffio->size = Fffi_size_of_type(type);
        ffio->type = type;
        ffio->plist = Qnil;

        /* Initialize foreign pointer */
        ffio->fotype = EFFI_FOT_NONE;
        ffio->storage_size = XINT(size);
        ffio->fop.ptr = ffio->fostorage;

        if (!NILP(Vffi_all_objects))
                XWEAK_LIST_LIST(Vffi_all_objects) =
                        Fcons(result, XWEAK_LIST_LIST(Vffi_all_objects));

        RETURN_UNGCPRO(result);
}

DEFUN("ffi-object-p", Fffi_object_p, 1, 1, 0, /*
Return non-nil if FO is an FFI object, nil otherwise.
*/
      (fo))
{
        return (EFFIOP(fo) ? Qt : Qnil);
}

DEFUN("ffi-object-address", Fffi_object_address, 1, 1, 0, /*
Return the address FO points to.
*/
      (fo))
{
        CHECK_EFFIO(fo);
        return make_float((long)XEFFIO(fo)->fop.ptr);
}

DEFUN("ffi-make-pointer", Fffi_make_pointer, 1, 1, 0, /*
  "Return a pointer pointing to ADDRESS."
*/
      (address))
{
        long addr;
        Lisp_Object ptr;

        if (INTP(address))
                addr = XINT(address);
        else if (FLOATP(address))
                addr = XFLOATINT(address);
        else {
#ifdef SXEMACS
                signal_simple_error("FFI: invalid address type", address);
#else
                signal_error(Qinternal_error, "FFI: invalid address type",
                             address);
#endif  /* SXEMACS */
        }

        ptr = Fmake_ffi_object(Q_pointer, Qnil);
        XEFFIO(ptr)->fop.ptr = (void*)addr;
        return ptr;
}

DEFUN("ffi-object-canonical-type", Fffi_object_canonical_type, 1, 1, 0, /*
Return FO's real type, that is after resolving user defined types.
*/
      (fo))
{
        CHECK_EFFIO(fo);
        return ffi_canonicalise_type(XEFFIO(fo)->type);
}

DEFUN("ffi-object-type", Fffi_object_type, 1, 1, 0, /*
Return FO's type.
*/
      (fo))
{
        CHECK_EFFIO(fo);
        return (XEFFIO(fo)->type);
}

DEFUN("ffi-set-object-type", Fffi_set_object_type, 2, 2, 0, /*
Cast FO to type TYPE and reassign the cast value.
*/
      (fo, type))
{
        CHECK_EFFIO(fo);

        ffi_check_type(type);
        XEFFIO(fo)->type = type;

        return type;
}

DEFUN("ffi-object-size", Fffi_object_size, 1, 1, 0, /*
Return the size of the allocated space of FO.
*/
      (fo))
{
        CHECK_EFFIO(fo);
        return (XEFFIO(fo)->size);
}

DEFUN("ffi-set-storage-size", Fffi_set_storage_size, 2, 2, 0, /*
Set the size of the allocated space of FO.
*/
      (fo, size))
{
        CHECK_EFFIO(fo);
        CHECK_INT(size);
        XEFFIO(fo)->storage_size = XUINT(size);
        return Qt;
}

DEFUN("ffi-load-library", Fffi_load_library, 1, 1, 0, /*
Load library LIBNAME and return a foreign object handle if successful,
or `nil' if the library cannot be loaded.

The argument LIBNAME should be the file-name string of a shared object
library.  Normally you should omit the file extension, as this
function will add the appripriate extension for the current platform
if one is missing.

The library should reside in one of the directories specified by the
$LD_LIBRARY_PATH environment variable or the more global ld.so.cache.
*/
      (libname))
{

#ifdef LTDL_SHLIB_EXT
#  define EXT LTDL_SHLIB_EXT
#elif defined(HAVE_DYLD) || defined(HAVE_MACH_O_DYLD_H)
#    define EXT ".dylib"
#  else
#    define EXT ".so"
#endif  /* LTDL_SHLIB_EXT */

        void *handler, *dotpos;
        Lisp_Object fo = Qnil;
        Lisp_EffiObject *ffio;
        struct gcpro gcpro1;
        char *soname = NULL;

        CHECK_STRING(libname);

        /* Add an extension if we need to */
        dotpos = strrchr((char *)XSTRING_DATA(libname),'.');
        if ( dotpos == NULL || strncmp(dotpos, EXT, sizeof(EXT))) {
                ssize_t liblen = XSTRING_LENGTH(libname);
                ssize_t soname_len = liblen + sizeof(EXT);
                soname = xmalloc( soname_len + 1);
                strncpy(soname, (char *)XSTRING_DATA(libname), liblen+1);
                strncat(soname, EXT, sizeof(EXT)+1);
        }

        if ( soname == NULL ) {
                handler = dlopen((const char *)XSTRING_DATA(libname),
                                 RTLD_GLOBAL|RTLD_NOW);
        } else {
                handler = dlopen(soname, RTLD_GLOBAL|RTLD_NOW);
                xfree(soname);
        }

        if (handler == NULL)
                return Qnil;
        
        GCPRO1(fo);
        fo = Fmake_ffi_object(Q_pointer, Qnil);
        ffio = XEFFIO(fo);

        ffio->fotype = EFFI_FOT_BIND;
        ffio->fop.ptr = handler;
        
        RETURN_UNGCPRO(fo);
}

DEFUN("ffi-bind", Fffi_bind, 2, 2, 0, /*
Make and return a foreign object of type TYPE and bind it to the
external symbol SYM.

The argument TYPE can be any type-cell.
The argument SYM should be a string naming an arbitrary symbol
in one of the loaded libraries.

If SYM does not exist in any of the loaded libraries, `nil' is
returned.
*/
      (type, sym))
{
        Lisp_Object fo = Qnil;
        Lisp_EffiObject *ffio;
        struct gcpro gcpro1;

        ffi_check_type(type);
        CHECK_STRING(sym);

        GCPRO1(fo);
        fo = Fmake_ffi_object(type, Qnil);
        ffio = XEFFIO(fo);
        ffio->fop.ptr = dlsym(RTLD_DEFAULT, (const char*)XSTRING_DATA(sym));
        if (ffio->fop.ptr == NULL) {
                UNGCPRO;
                return Qnil;
        }

        ffio->fotype = EFFI_FOT_BIND;

        RETURN_UNGCPRO(fo);
}

DEFUN("ffi-dlerror", Fffi_dlerror, 0, 0, 0, /*
Return dl error string.
*/
      ())
{
        const char *dles = dlerror();

        if (LIKELY(dles != NULL)) {
                size_t sz = strlen(dles);
                return make_ext_string((const Extbyte*)dles, sz, EFFI_CODING);
        } else {
                return Qnil;
        }
}

DEFUN("ffi-defun", Fffi_defun, 2, 2, 0, /*
Make and return a foreign object of type TYPE and bind it to the
external symbol SYM.

The argument TYPE should be a function type-cell.
The argument SYM should be a string naming a function in one of
the loaded libraries.

If SYM does not exist in any of the loaded libraries, an error
is indicated.

This is like `ffi-bind' but for function objects.
*/
      (type, sym))
{
        Lisp_Object fo = Qnil;
        Lisp_EffiObject *ffio;
        struct gcpro gcpro1;

        ffi_check_type(type);
        CHECK_STRING(sym);
        
        GCPRO1(fo);

        fo = Fmake_ffi_object(type, Qnil);
        ffio = XEFFIO(fo);
        ffio->fop.fun = dlsym(RTLD_DEFAULT, (const char *)XSTRING_DATA(sym));
        if (ffio->fop.fun == NULL) {
#ifdef SXEMACS
                signal_simple_error("Can't define function", sym);
#else
                signal_error(Qinternal_error, "Can't define function", sym);
#endif  /* SXEMACS */
        }

        ffio->fotype = EFFI_FOT_FUNC;

        RETURN_UNGCPRO(fo);
}

/*
 * Return alignment policy for struct or union FFI_SU.
 * x86: Return 1, 2 or 4.
 * mips: Return 1, 2, 4 or 8.
 */
static int
ffi_type_align(Lisp_Object type)
{
        type = ffi_canonicalise_type(type);
        if (SYMBOLP(type)) {
                if (EQ(type, Q_byte) || EQ(type, Q_unsigned_byte)
                    || EQ(type, Q_char) || EQ(type, Q_unsigned_char))
                        return 1;
                if (EQ(type, Q_short) || EQ(type, Q_unsigned_short))
                        return 2;
#ifdef FFI_MIPS
                if (EQ(type, Q_double))
                        return 8;
#endif  /* FFI_MIPS */
                return 4;
                /* NOT REACHED */
        } else if (CONSP(type)
                   && (EQ(XCAR(type), Q_struct) || EQ(XCAR(type), Q_union))) {
                int al;

                for (al = 0, type = Fcdr(Fcdr(type));
                     !NILP(type);
                     type = Fcdr(type))
                {
                        Lisp_Object stype = Fcar(Fcdr(Fcar(type)));
                        int tmp_al = ffi_type_align(stype);

                        if (tmp_al > al)
                                al = tmp_al;
                }

                return al;
        }

        return 4;
}

DEFUN("ffi-type-alignment", Fffi_type_alignment, 1, 1, 0, /*
Return TYPE alignment.
*/
      (type))
{
        return make_int(ffi_type_align(type));
}

DEFUN("ffi-slot-offset", Fffi_slot_offset, 2, 2, 0, /*
Return the offset of SLOT in TYPE.
SLOT can be either a valid (named) slot in TYPE or `nil'.
If SLOT is `nil' return the size of the struct.
*/
      (type, slot))
{
        Lisp_Object slots;
        int lpad, align, retoff;

        type = ffi_canonicalise_type(type);
        if (!CONSP(type)) {
#ifdef SXEMACS
                error("Not struct or union");
#else
                Fsignal(Qwrong_type_argument,
                        list2(Qstringp, build_string("Not struct or union")));
#endif  /* SXEMACS */
        }

        retoff = 0;
        lpad = align = ffi_type_align(type);
        slots = Fcdr(XCDR(type));
        CHECK_CONS(slots);
        while (!NILP(slots)) {
                Lisp_Object tmp_slot = Fcar(Fcdr(XCAR(slots)));
                int tmp_align;
                int tmp_size;

                /*
                 * NOTE:
                 *  - for basic types TMP_ALIGN and TMP_SIZE are equal
                 */
                tmp_align = ffi_type_align(tmp_slot);

                if (EQ(XCAR(XCAR(slots)), slot)) {
                        /* SLOT found */
                        /* TODO: add support for :offset keyword in SLOT */
                        if (lpad < tmp_align) {
                                retoff += lpad;
                                lpad = 0;
                        } else
                                lpad -= tmp_align;
                        break;
                }

                tmp_size = XINT(Fffi_size_of_type(tmp_slot));
                while (tmp_size > 0) {
                        if (lpad < tmp_align) {
                                retoff += lpad;
                                lpad = align;
                        }
                        tmp_size -= tmp_align;
                        lpad -= tmp_align;
                        retoff += tmp_align;
                }

                slots = XCDR(slots);
        }
        if (NILP(slots) && !NILP(slot)) {
#ifdef SXEMACS
                signal_simple_error("FFI: Slot not found", slot);
#else
                signal_error(Qinternal_error, "FFI: Slot not found", slot);
#endif  /* SXEMACS */
        }
        return make_int(retoff + lpad);
}

/*
 * TYPE must be already canonicalised
 */
static Lisp_Object
ffi_fetch_foreign(void *ptr, Lisp_Object type)
{
/* this function canNOT GC */
        Lisp_Object retval = Qnone;

        if (EQ(type, Q_char))
                retval = make_char(*(char*)ptr);
        else if (EQ(type, Q_unsigned_char))
                retval = make_char(*(char unsigned*)ptr);
        else if (EQ(type, Q_byte))
                retval = make_int(*(char*)ptr);
        else if (EQ(type, Q_unsigned_byte))
                retval = make_int(*(unsigned char*)ptr);
        else if (EQ(type, Q_short))
                retval = make_int(*(short*)ptr);
        else if (EQ(type, Q_unsigned_short))
                retval = make_int(*(unsigned short*)ptr);
        else if (EQ(type, Q_int))
                retval = make_int(*(int*)ptr);
        else if (EQ(type, Q_unsigned_int))
                retval = make_int(*(unsigned int*)ptr);
        else if (EQ(type, Q_long))
                retval = make_int(*(long*)ptr);
        else if (EQ(type, Q_unsigned_long))
                retval = make_int(*(unsigned long*)ptr);
        else if (EQ(type, Q_float))
                retval = make_float(*(float*)ptr);
        else if (EQ(type, Q_double))
                retval = make_float(*(double*)ptr);
        else if (EQ(type, Q_c_string)) {
                retval = build_ext_string((char*)ptr, Qbinary);
        } else if (EQ(type, Q_void)) {
                retval = Qnil;
        } else if (FFI_POINTERP(type)) {
                retval = Fmake_ffi_object(type, Qnil);
                XEFFIO(retval)->fop.ptr = *(void**)ptr;
        } else if (CONSP(type) && EQ(XCAR(type), Q_function)) {
                retval = Fmake_ffi_object(type, Qnil);
                XEFFIO(retval)->fop.fun = (void*)ptr;
                XEFFIO(retval)->fotype = EFFI_FOT_FUNC;
        }

        return retval;
}

DEFUN("ffi-fetch", Fffi_fetch, 3, 3, 0, /*
Fetch value from the foreign object FO from OFFSET position.
TYPE specifies value for data to be fetched.
*/
      (fo, offset, type))
{
        Lisp_Object origtype = type;
        Lisp_Object retval = Qnil;
        Lisp_EffiObject *ffio;
        void *ptr;
        struct gcpro gcpro1;

        CHECK_EFFIO(fo);
        CHECK_INT(offset);

        ffio = XEFFIO(fo);
        ptr = (void*)((char*)ffio->fop.ptr + XINT(offset));

        type = ffi_canonicalise_type(type);

        GCPRO1(retval);
        /* Fetch value and translate it according to translators */
        retval = ffi_fetch_foreign(ptr, type);
        if (EQ(retval, Qnone)) {
                /* Special case for c-data */
                if (EQ(type, Q_c_data) ||
                    (CONSP(type) && EQ(XCAR(type), Q_c_data)))
                {
                        size_t tlen;
                        if (EQ(type, Q_c_data)) {
                                tlen = ffio->storage_size - XINT(offset);
                        } else {
                                CHECK_INT(XCDR(type));
                                tlen = XUINT(XCDR(type));
                        }

                        retval = make_ext_string(ptr, tlen, Qbinary);
                } else {
#ifdef SXEMACS
                        signal_simple_error("Can't fetch for this type", origtype);
#else
                        signal_error(Qinternal_error, "Can't fetch for this type",
                                     origtype);
#endif  /* SXEMACS */
                }
        }
        retval = apply1(Findirect_function(Qffi_translate_from_foreign),
                        list2(retval, origtype));

        RETURN_UNGCPRO(retval);
}

DEFUN("ffi-aref", Fffi_aref, 2, 2, 0, /*
Return the element of FARRAY at index IDX (starting with 0).
*/
      (farray, idx))
{
        Lisp_Object type;
        
        CHECK_EFFIO(farray);
        CHECK_INT(idx);
        
        type = ffi_canonicalise_type(XEFFIO(farray)->type);
        if (!FFI_TPTR(type)) {
#ifdef SXEMACS
                signal_simple_error("Not an array type", type);
#else
                signal_error(Qinternal_error, "Not an array type", type);
#endif  /* SXEMACS */
        }
        if (EQ(type, Q_c_string))
                type = Q_char;
        else
                type = Fcar(XCDR(type));

        return Fffi_fetch(farray,
                          make_int(XINT(Fffi_size_of_type(type)) * XINT(idx)),
                          type);
}

DEFUN("ffi-store", Fffi_store, 4, 4, 0, /*
For foreign object FO at specified OFFSET store data.
Type of data is specified by VAL-TYPE and data itself specified in VAL.

VAL-TYPE can be either a basic FFI type or an FFI pointer.
If VAL-TYPE is a basic FFI type, then VAL can be an
ordinary, but suitable Emacs lisp object.
If VAL-TYPE is an FFI pointer then VAL _must_ be an FFI
object of the underlying type pointed to.
*/
      (fo, offset, val_type, val))
{
        Lisp_Object origtype = val_type;
        Lisp_EffiObject *ffio;
        void *ptr;

        CHECK_EFFIO(fo);
        CHECK_INT(offset);

        ffio = XEFFIO(fo);
        ptr = (void*)((char*)ffio->fop.ptr + XINT(offset));

        val_type = ffi_canonicalise_type(val_type);

        /* Translate value */
        val = apply1(Findirect_function(Qffi_translate_to_foreign),
                     list2(val, origtype));

        if (EQ(val_type, Q_char) || EQ(val_type, Q_unsigned_char)) {
                if (!CHARP(val)) {
                        SIGNAL_ERROR(Qwrong_type_argument,
                                     list2(Qcharacterp, val));
                }
                *(char*)ptr = XCHAR(val);
        } else if (EQ(val_type, Q_byte) || EQ(val_type, Q_unsigned_byte)) {
                if (!INTP(val)) {
                        SIGNAL_ERROR(Qwrong_type_argument,
                                     list2(Qintegerp, val));
                }
                *(char*)ptr = XINT(val);
        } else if (EQ(val_type, Q_short) || EQ(val_type, Q_unsigned_short)) {
                if (!INTP(val)) {
                        SIGNAL_ERROR(Qwrong_type_argument,
                                     list2(Qintegerp, val));
                }
                *(short*)ptr = (short)XINT(val);
        } else if (EQ(val_type, Q_int) || EQ(val_type, Q_unsigned_int)) {
                if (INTP(val)) {
                        *(int*)ptr = XINT(val);
                } else if (FLOATP(val)) {
                        fpfloat tmp = XFLOATINT(val);
                        *(int*)ptr = (int)tmp;
                } else {
                        SIGNAL_ERROR(Qwrong_type_argument,
                                     list2(Qfloatp, val));
                }
        } else if (EQ(val_type, Q_long) || EQ(val_type, Q_unsigned_long)) {
                if (INTP(val)) {
                        *(long*)ptr = (long)XINT(val);
                } else if (FLOATP(val)) {
                        fpfloat tmp = XFLOATINT(val);
                        *(long*)ptr = (long int)tmp;
                } else {
                        SIGNAL_ERROR(Qwrong_type_argument, list2(Qfloatp, val));
                }
        } else if (EQ(val_type, Q_float)) {
                if (!FLOATP(val))
                        SIGNAL_ERROR(Qwrong_type_argument, list2(Qfloatp, val));
                *(float*)ptr = XFLOATINT(val);
        } else if (EQ(val_type, Q_double)) {
                if (!FLOATP(val))
                        SIGNAL_ERROR(Qwrong_type_argument, list2(Qfloatp, val));
                *(double*)ptr = XFLOAT_DATA(val);
        } else if (EQ(val_type, Q_c_string)) {
                char *tmp;
                int tmplen;
                if (!STRINGP(val))
                        SIGNAL_ERROR(Qwrong_type_argument, list2(Qstringp, val));
#if defined(MULE)
                TO_EXTERNAL_FORMAT(LISP_STRING, val,
                                   ALLOCA, (tmp, tmplen), Qnil);
                memcpy((char*)ptr, tmp, tmplen + 1);
#else
                memcpy((char*)ptr,
                       (const char *)XSTRING_DATA(val),
                       XSTRING_LENGTH(val) + 1);
#endif
        } else if (EQ(val_type, Q_c_data) ||
                   (CONSP(val_type) &&
                    EQ(XCAR(val_type), Q_c_data) && INTP(XCDR(val_type)))) {
                char *val_ext;
                unsigned int val_ext_len;
                if (!STRINGP(val))
                        SIGNAL_ERROR(Qwrong_type_argument, list2(Qstringp, val));

                TO_EXTERNAL_FORMAT(LISP_STRING, val, ALLOCA,
                                   (val_ext, val_ext_len), Qbinary);
                if (CONSP(val_type) && (val_ext_len > XINT(XCDR(val_type)))) {
#ifdef SXEMACS
                        error("storage size too small");
#else
                        Fsignal(Qrange_error,
                                list2(Qstringp,
                                      build_string("storage size too small")));
#endif  /* SXEMACS */
                }
                memcpy((char*)ptr, (const char *)val_ext, val_ext_len);
        } else if (FFI_POINTERP(val_type)) {
                if (!EFFIOP(val)) {
#ifdef SXEMACS
                        signal_simple_error("FFI: Value not of pointer type", \
                                            list2(origtype, val));
#else
                        Fsignal(Qwrong_type_argument,
                                list2(Qstringp, build_string("type")));
#endif  /* SXEMACS */
                }
                *(void**)ptr = (void*)XEFFIO(val)->fop.ptr;
        } else if (CONSP(val_type) && EQ(XCAR(val_type), Q_struct)) {
                if (!EFFIOP(val)) {
#ifdef SXEMACS
                        signal_simple_error("FFI: Value not FFI object", \
                                            list2(origtype, val));
#else
                        Fsignal(Qwrong_type_argument,
                                list2(Qstringp, build_string("type")));
#endif  /* SXEMACS */
                }
                memcpy((char*)ptr, (const char *)XEFFIO(val)->fop.ptr, \
                       XINT(Fffi_size_of_type(val_type)));
        } else {
#ifdef SXEMACS
                signal_simple_error("FFI: Non basic or pointer type", origtype);
#else
                Fsignal(Qinternal_error,
                        list2(Qstringp,
                              build_string("non basic or pointer type")));
#endif  /* SXEMACS */
        }

        return val;
}

DEFUN("ffi-aset", Fffi_aset, 3, 3, 0, /*
Store the element VALUE in FARRAY at index IDX (starting with 0).
*/
      (farray, idx, value))
{
        Lisp_Object type;
        
        CHECK_EFFIO(farray);
        CHECK_INT(idx);
        
        type = ffi_canonicalise_type(XEFFIO(farray)->type);
        if (!FFI_TPTR(type)) {
#ifdef SXEMACS
                signal_simple_error("Not an array type", type);
#else
                signal_error(Qinternal_error, "Not an array type", type);
#endif  /* SXEMACS */
        }
        if (EQ(type, Q_c_string))
                type = Q_char;
        else
                type = Fcar(XCDR(type));

        return Fffi_store(farray,
                          make_int(XINT(Fffi_size_of_type(type)) * XINT(idx)),
                          type, value);
}

DEFUN("ffi-address-of", Fffi_address_of, 1, 1, 0, /*
Return the FFI object that stores the address of given FFI object FO.

This is the equivalent of the `&' operator in C.
*/
      (fo))
{
        Lisp_Object newfo = Qnil;
        Lisp_EffiObject *ffio, *newffio;
        struct gcpro gcpro1;

        CHECK_EFFIO(fo);
        ffio = XEFFIO(fo);

        GCPRO1(newfo);
        newfo = Fmake_ffi_object(Q_pointer, Qnil);
        newffio = XEFFIO(newfo);

        newffio->fotype = EFFI_FOT_BIND;
        if (FFI_TPTR(ffio->type))
                newffio->fop.ptr = (void*)&ffio->fop.ptr;
        else
                newffio->fop.ptr = ffio->fop.ptr;

        RETURN_UNGCPRO(newfo);
}

DEFUN("ffi-lisp-object-to-pointer", Fffi_lisp_object_to_pointer, 1, 1, 0, /*
Convert lisp object to FFI pointer.
*/
      (obj))
{
        Lisp_Object newfo = Qnil;
        Lisp_EffiObject *newffio;
        struct gcpro gcpro1;

        GCPRO1(obj);

        newfo = Fmake_ffi_object(Q_pointer, Qnil);
        newffio = XEFFIO(newfo);
        newffio->fotype = EFFI_FOT_BIND;
        newffio->fop.ptr = (void*)obj;

        /* Hold a reference to OBJ in NEWFO's plist */
        Fput(newfo, intern("lisp-object"), obj);

        RETURN_UNGCPRO(newfo);
}

DEFUN("ffi-pointer-to-lisp-object", Fffi_pointer_to_lisp_object, 1, 1, 0, /*
Convert FFI pointer to lisp object.
*/
      (ptr))
{
        CHECK_EFFIO(ptr);
        return (Lisp_Object)XEFFIO(ptr)->fop.ptr;
}

DEFUN("ffi-plist", Fffi_plist, 1, 1, 0, /*
Return properties list for FFI object FO.
*/
      (fo))
{
        CHECK_EFFIO(fo);
        return (XEFFIO(fo)->plist);
}

#ifdef HAVE_LIBFFI

static int lf_cindex = 0;

/*
 * XXX
 *  This will work in most cases.
 *  However it might not work for large structures,
 *  In general we should allocate these spaces dynamically
 */
#define MAX_TYPES_VALUES 1024
/* ex_ffitypes_dummies used for structure types */
static ffi_type ex_ffitypes_dummies[MAX_TYPES_VALUES + 1];
static ffi_type *ex_ffitypes[MAX_TYPES_VALUES + 1];
static void *ex_values[MAX_TYPES_VALUES + 1];

#if SIZEOF_LONG == 4
#  define effi_type_ulong ffi_type_uint32
#  define effi_type_slong ffi_type_sint32
#elif SIZEOF_LONG == 8
#  define effi_type_ulong ffi_type_uint64
#  define effi_type_slong ffi_type_sint64
#endif

static void
extffi_setup_argument(Lisp_Object type, ffi_type **ft)
{
        type = ffi_canonicalise_type(type);
        if (EQ(type, Q_char) || EQ(type, Q_byte))
                *ft = &ffi_type_schar;
        else if (EQ(type, Q_unsigned_char) || EQ(type, Q_unsigned_byte))
                *ft = &ffi_type_uchar;
        else if (EQ(type, Q_short))
                *ft = &ffi_type_sshort;
        else if (EQ(type, Q_unsigned_short))
                *ft = &ffi_type_ushort;
        else if (EQ(type, Q_int))
                *ft = &ffi_type_sint;
        else if (EQ(type, Q_unsigned_int))
                *ft = &ffi_type_uint;
        else if (EQ(type, Q_unsigned_long))
                *ft = &effi_type_ulong;
        else if (EQ(type, Q_long))
                *ft = &effi_type_slong;
        else if (EQ(type, Q_float))
                *ft = &ffi_type_float;
        else if (EQ(type, Q_double))
                *ft = &ffi_type_double;
        else if (EQ(type, Q_void))
                *ft = &ffi_type_void;
        else if (FFI_TPTR(type))
                *ft = &ffi_type_pointer;
        else if (CONSP(type) && EQ(XCAR(type), Q_struct)) {
                Lisp_Object slots = Fcdr(XCDR(type));
                ffi_type **ntypes;
                int nt_size, i;

                CHECK_CONS(slots);

                nt_size = XINT(Flength(slots)) + 1;
                if (nt_size + lf_cindex > MAX_TYPES_VALUES) {
                        lf_cindex = 0;  /* reset cindex */
#ifdef SXEMACS
                        error("cindex overflow");
#else
                        Fsignal(Qoverflow_error,
                                list2(Qstringp,
                                      build_string("cindex overflow")));
#endif  /* SXEMACS */
                }
                ntypes = &ex_ffitypes[lf_cindex];
                *ft = &ex_ffitypes_dummies[lf_cindex];

                /* Update lf_cindex in case TYPE struct contains other
                 * structures */
                lf_cindex += nt_size;

                (*ft)->type = FFI_TYPE_STRUCT;
                (*ft)->alignment = ffi_type_align(type);
                (*ft)->elements = ntypes;

                for (i = 0; (i < nt_size) && !NILP(slots); slots = XCDR(slots), i++)
                        extffi_setup_argument(Fcar(Fcdr(XCAR(slots))), &ntypes[i]);
                ntypes[i] = NULL;
        } else {
#ifdef SXEMACS
                signal_simple_error("Can't setup argument for type", type);
#else
                signal_error(Qinternal_error,
                             "Can't setup argument for type", type);
#endif  /* SXEMACS */
        }
}

static int
ffi_call_using_libffi(Lisp_Object fo_fun, Lisp_Object ret_fo,
                      int in_nargs, Lisp_Object *in_args)
{
        Lisp_EffiObject *ffio;
        Lisp_Object fft;
        ffi_cif cif;
        ffi_type *rtype;
        void *rvalue;
        int i;

        lf_cindex = in_nargs;           /* reserve */
        for (i = 0; i < in_nargs; i++) {
                ffio = XEFFIO(in_args[i]);
                fft = Fffi_canonicalise_type(ffio->type);
                extffi_setup_argument(fft, &ex_ffitypes[i]);
                if (FFI_TPTR(fft))
                        ex_values[i] = &ffio->fop.ptr;
                else
                        ex_values[i] = ffio->fop.ptr;
        }

        ffio = XEFFIO(ret_fo);
        fft = Fffi_canonicalise_type(ffio->type);
        extffi_setup_argument(fft, &rtype);
        if (FFI_TPTR(fft))
                rvalue = &ffio->fop.ptr;
        else
                rvalue = ffio->fop.ptr;

        if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, in_nargs,
                         rtype, ex_ffitypes) == FFI_OK)
        {
                stop_async_timeouts();
                ffi_call(&cif, (void(*)(void))XEFFIO(fo_fun)->fop.fun, rvalue,
                         ex_values);
                start_async_timeouts();
                return 0;
        }

        /* FAILURE */
        return 1;
}
#endif  /* HAVE_LIBFFI */

DEFUN("ffi-call-function", Fffi_call_function, 1, MANY, 0, /*
Call a function referred to by FO with arguments ARGS, maybe
return a foreign object with the result or nil if there is
none.

Arguments are: FO &rest FO-ARGS

FO should be a foreign binding initiated by `ffi-defun', and
ARGS should be foreign data objects or pointers to these.
*/
      (int nargs, Lisp_Object * args))
{
        Lisp_Object faf = Qnil, retfo = Qnil;
        Lisp_EffiObject *ffio;
        int ret = -1;
        struct gcpro gcpro1, gcpro2;

        GCPRO2(faf, retfo);

        faf =  args[0];
        ffio = XEFFIO(faf);
        retfo = Fmake_ffi_object(XCAR(XCDR(ffio->type)), Qnil);

#ifdef HAVE_LIBFFI
        ret = ffi_call_using_libffi(args[0], retfo, nargs-1, &args[1]);
#endif  /* HAVE_LIBFFI */

        RETURN_UNGCPRO(ret == 0 ? retfo : Qnil);
}

#ifdef EF_USE_ASYNEQ
/* handler for asynchronously calling ffi code */
Lisp_Object Qffi_jobp;
#define EFFI_DEBUG_JOB(args...)
static Lisp_Object
exec_sentinel_unwind(Lisp_Object UNUSED(datum))
{
        return Qnil;
}

static inline void
exec_sentinel(void *job, ffi_job_t ffij)
        __attribute__((always_inline));
static inline void
exec_sentinel(void *job, ffi_job_t ffij)
{
        /* This function can GC */
        /* called from main thread */
        int speccount = specpdl_depth(), nargs = ffij->sntnl_nargs, i;
        Lisp_Object funcell[nargs+2];
        struct gcpro gcpro1;

        funcell[0] = ffij->sntnl;
        funcell[1] = (Lisp_Object)job;
        for (i = 0; i < nargs; i++) {
                funcell[2+i] = ffij->sntnl_args[i];
        }
        GCPROn(funcell, nargs+2);

        record_unwind_protect(exec_sentinel_unwind, Qnil);
        /* call the funcell */
        Ffuncall(nargs+2, funcell);
        /* reset to previous state */
        restore_match_data();
        UNGCPRO;
        unbind_to(speccount, Qnil);
        return;
}

static inline ffi_job_t
allocate_ffi_job(void)
{
        ffi_job_t ffij = xnew(struct ffi_job_s);
        EFFI_DEBUG_JOB("allocated: 0x%lx\n", (long unsigned int)ffij);
        return ffij;
}

static inline ffi_job_t
make_ffi_job(Lisp_Object fof, int fof_nargs, Lisp_Object *fof_args,
             Lisp_Object sntnl, int sntnl_nargs, Lisp_Object *sntnl_args)
{
/* exec'd in the main thread */
        ffi_job_t ffij = allocate_ffi_job();
        int i;

        SXE_MUTEX_INIT(&ffij->mtx);
        ffij->fof = fof;
        if (fof_nargs > 0) {
                ffij->fof_nargs = fof_nargs;
                ffij->fof_args = xnew_array(Lisp_Object, fof_nargs);
                for (i = 0; i < fof_nargs; i++) {
                        ffij->fof_args[i] = fof_args[i];
                }
        } else {
                ffij->fof_nargs = 0;
                ffij->fof_args = NULL;
        }

        ffij->sntnl = sntnl;
        if (sntnl_nargs > 0) {
                ffij->sntnl_nargs = sntnl_nargs;
                ffij->sntnl_args = xnew_array(Lisp_Object, sntnl_nargs);
                for (i = 0; i < sntnl_nargs; i++) {
                        ffij->sntnl_args[i] = sntnl_args[i];
                }
        } else {
                ffij->sntnl_nargs = 0;
                ffij->sntnl_args = NULL;
        }

        ffij->result = Qnil;
        ffij->retfo = Fmake_ffi_object(XCAR(XCDR(XEFFIO(fof)->type)), Qnil);
        return ffij;
}

static void
mark_ffi_job(worker_job_t job)
{
        ffi_job_t ffij = ffi_job(job);
        int i;

        if (!ffij)
                return;

        SXE_MUTEX_LOCK(&ffij->mtx);
        mark_object(ffij->fof);
        for (i = 0; i < ffij->fof_nargs; i++) {
                mark_object(ffij->fof_args[i]);
        }
        mark_object(ffij->sntnl);
        for (i = 0; i < ffij->sntnl_nargs; i++) {
                mark_object(ffij->sntnl_args[i]);
        }
        mark_object(ffij->retfo);
        mark_object(ffij->result);
        SXE_MUTEX_UNLOCK(&ffij->mtx);
        return;
}

static void
print_ffi_job(worker_job_t job, Lisp_Object pcf)
{
        ffi_job_t ffij = ffi_job(job);
        char *str = alloca(64);

        SXE_MUTEX_LOCK(&ffij->mtx);
        WRITE_C_STRING(" carrying ", pcf);
        snprintf(str, 63, " #<ffi-job 0x%lx>", (long unsigned int)ffij);
        WRITE_C_STRING(str, pcf);
        SXE_MUTEX_UNLOCK(&ffij->mtx);
        return;
}

static inline void
finish_ffi_job_data(ffi_job_t ffij)
{
        SXE_MUTEX_LOCK(&ffij->mtx);
        xfree(ffij->fof_args);
        xfree(ffij->sntnl_args);
        SXE_MUTEX_UNLOCK(&ffij->mtx);
        SXE_MUTEX_FINI(&ffij->mtx);

        EFFI_DEBUG_JOB("finished: 0x%lx\n", (long unsigned int)ffij);
        xfree(ffij);
}

static void
finish_ffi_job(worker_job_t job)
{
        ffi_job_t ffij;

        lock_worker_job(job);
        ffij = ffi_job(job);

        if (ffij) {
                finish_ffi_job_data(ffij);
        }
        worker_job_data(job) = NULL;
        unlock_worker_job(job);
        return;
}

static void
ffi_job_handle(worker_job_t job)
{
        /* thread-safe */
        /* usually called from aux threads */
        ffi_job_t ffij;
        Lisp_Object fof = Qnil, retfo = Qnil, *args = NULL;
        int nargs, ret = -1;

        lock_worker_job(job);
        ffij = ffi_job(job);
        unlock_worker_job(job);
        SXE_MUTEX_LOCK(&ffij->mtx);
        fof = ffij->fof;
        nargs = ffij->fof_nargs;
        args = ffij->fof_args;
        SXE_MUTEX_UNLOCK(&ffij->mtx);

        /* can't ... Fmake_ffi_object is not mt-safe */
        /* retfo = Fmake_ffi_object(XCAR(XCDR(XEFFIO(fof)->type)), Qnil); */
        retfo = ffij->retfo;

#ifdef HAVE_LIBFFI
        ret = ffi_call_using_libffi(fof, retfo, nargs, args);
#endif  /* HAVE_LIBFFI */
        if (ret == 0) {
                SXE_MUTEX_LOCK(&ffij->mtx);
                ffij->result = retfo;
                SXE_MUTEX_UNLOCK(&ffij->mtx);
        }

        EFFI_DEBUG_JOB("job 0x%lx succeeded\n", (long unsigned int)ffij);
        return;
}

static void
ffi_job_finished(worker_job_t job)
{
        if (NILP(ffi_job_sentinel(job) /* sentinel */)) {
                return;
        }
        /* called from main thread */
        exec_sentinel(job, ffi_job(job));
        return;
}

static struct work_handler_s ffi_job_handler = {
        mark_ffi_job, print_ffi_job, finish_ffi_job,
        ffi_job_handle, NULL, ffi_job_finished
};

static Lisp_Object
make_ffi_asyneq_job(ffi_job_t ffij)
{
        /* create a job digestible by the asyneq */
        Lisp_Object job = Qnil;
        struct gcpro gcpro1;

        GCPRO1(job);
        job = wrap_object(make_worker_job(&ffi_job_handler));
        XWORKER_JOB_DATA(job) = ffij;
        /* the scratch buffer thingie */
        UNGCPRO;
        return job;
}

DEFUN("ffi-call-function&", Fffi_call_functionX, 1, MANY, 0, /*
Call a function referred to by FO with arguments ARGS asynchronously,
return a job object.

Arguments are: FO &rest FO-ARGS &aux SENTINEL &rest SENTINEL-ARGS

FO should be a foreign binding initiated by `ffi-defun'.
FO-ARGS should be exactly as many foreign data objects as FO needs.
SENTINEL is a lisp sentinel function called when the job finished,
  the function should take at least one argument JOB, further arguments
  may be specified by passing further SENTINEL-ARGS.
*/
      (int nargs, Lisp_Object *args))
{
        Lisp_Object job = Qnil;
        Lisp_Object sntnl, fof, *sntnl_args, *fof_args;
        int sntnl_nargs, fof_nargs;
        ffi_job_t ffij;
        struct gcpro gcpro1, gcpro2;

        CHECK_EFFIO(args[0]);
        GCPRO1n(job, args, nargs);

        fof = args[0];
        /* determine how many args belong to the fof */
        fof_nargs = XINT(Flength(XCDR(XEFFIO(fof)->type)))-1;
        fof_args = &args[1];

        if ((sntnl_nargs = nargs - fof_nargs - 2) >= 0) {
                sntnl = args[fof_nargs+1];
                sntnl_args = &args[fof_nargs+2];
        } else {
                sntnl = Qnil;
                sntnl_args = NULL;
        }

        /* create the job data object */
        ffij = make_ffi_job(fof, fof_nargs, fof_args,
                            sntnl, sntnl_nargs, sntnl_args);
        /* now prepare the job to dispatch */
        job = make_ffi_asyneq_job(ffij);
        /* ... and dispatch it, change its state to queued */
        XWORKER_JOB_STATE(job) = WORKER_JOB_QUEUED;
        eq_enqueue(delegate_eq, job);
        /* brag about new jobs in the queue */
        eq_queue_trigger_all(delegate_eq);

        UNGCPRO;
        return job;
}
#endif  /* EF_USE_ASYNEQ */

extern struct device *decode_x_device(Lisp_Object device);

DEFUN("x-device-display", Fx_device_display, 0, 1, 0,   /*
Return DEVICE display as FFI object.
*/
      (device))
{
#if HAVE_X_WINDOWS
        Lisp_Object fo;

        fo = Fmake_ffi_object(Q_pointer, Qnil);
        XEFFIO(fo)->fotype = EFFI_FOT_BIND;
        XEFFIO(fo)->fop.ptr = (void*)DEVICE_X_DISPLAY(decode_x_device(device));
        return fo;
#else
        return Qnil;
#endif
}

/* Callbacks */
#define FFI_CC_CDECL 0

#if defined __i386__
static void
ffi_callback_call_x86(Lisp_Object cbk_info, char *arg_buffer)
{
        Lisp_Object fun, alist = Qnil, retlo, foret;
        Lisp_Object rtype, argtypes;
        struct gcpro gcpro1, gcpro2, gcpro3, gcpro4, gcpro5;
        void *ptr;

        fun = Fcar(cbk_info);
        rtype = Fcar(Fcdr(cbk_info));
        argtypes = Fcar(Fcdr(Fcdr(cbk_info)));

        CHECK_LIST(argtypes);

        arg_buffer += 4;                /* Skip return address */
        while (!NILP(argtypes)) {
                Lisp_Object result, ctype;
                int size;
 
                ctype = ffi_canonicalise_type(XCAR(argtypes));
                size = XINT(Fffi_size_of_type(ctype));
                if (EQ(ctype, Q_c_string)) {
                        char *aptr = *(char**)arg_buffer;
                        if (aptr)
                                result = ffi_fetch_foreign(aptr, ctype);
                        else
                                result = Qnil;
                } else
                        result = ffi_fetch_foreign(arg_buffer, ctype);
                /* Apply translators and put the result into alist */
                result = apply1(Findirect_function(Qffi_translate_from_foreign),
                                list2(result, XCAR(argtypes)));
                alist = Fcons(result, alist);
                {
                        int mask = 3;
                        int sp = (size + mask) & ~mask;
                        arg_buffer += (sp);
                }
                argtypes = XCDR(argtypes);
        }
        alist = Fnreverse(alist);

        /* Special case, we have no return value */
        if (EQ(rtype, Q_void)) {
                GCPRO3(fun, alist, rtype);
                apply1(fun, alist);
                UNGCPRO;
                return;
        }

        GCPRO5(fun, alist, rtype, retlo, foret);
        retlo = apply1(fun, alist);
        foret = Fmake_ffi_object(rtype, Qnil);
        Fffi_store(foret, make_int(0), rtype, retlo);
        ptr = (void*)XEFFIO(foret)->fop.ptr;
        if (EQ(rtype, Q_double)) {
                UNGCPRO;
                {
                asm volatile ("fldl (%0)" :: "a" (ptr));
                }
                return;
        } else if (EQ(rtype, Q_float)) {
                UNGCPRO;
                {
                asm volatile ("flds (%0)" :: "a" (ptr));
                }
                return;
        } else {
                int iv;

                if (EQ(rtype, Q_byte) || EQ(rtype, Q_char))
                        iv = *(char*)ptr;
                else if (EQ(rtype, Q_unsigned_byte) || EQ(rtype, Q_unsigned_char))
                        iv = *(char unsigned*)ptr;
                else if (EQ(rtype, Q_short))
                        iv = *(short*)ptr;
                else if (EQ(rtype, Q_unsigned_short))
                        iv = *(unsigned short*)ptr;
                else
                        iv = *(int*)ptr;
                UNGCPRO;
                {
                        asm volatile ("movl %0,%%eax;" :: "r" (iv) : "%eax");
                }
                return;
        }
}

void*
ffi_make_callback_x86(Lisp_Object data, int cc_type)
{
        /*
         *      push    %esp                            54
         *      pushl   <data>                          68 <addr32>
         *      call    ffi_callback_call_x86           E8 <disp32>
         *      pop     %ecx                            59
         *      pop     %ecx                            59
         *      ret                                     c3
         *      nop                                     90
         *      nop                                     90
         */

        char *buf = xmalloc(sizeof(char)*16);
        *(char*) (buf+0)  = 0x54;
        *(char*) (buf+1)  = 0x68;
        *(long*) (buf+2)  = (long)data;
        *(char*) (buf+6)  = 0xE8;
        *(long*) (buf+7)  = (long)ffi_callback_call_x86 - (long)(buf+11);
        *(char*) (buf+11) = 0x59;
        *(char*) (buf+12) = 0x59;
        if (cc_type == FFI_CC_CDECL) {
                *(char*) (buf+13) = 0xc3;
                *(short*)(buf+14) = 0x9090;
        } else {
                Lisp_Object arg_types = Fcar(Fcdr(Fcdr(data)));
                int byte_size = 0;
                int mask = 3;

                CHECK_CONS(arg_types);

                while (!NILP(arg_types)) {
                        int sz = XINT(Fffi_size_of_type(XCAR(arg_types)));
                        byte_size += ((sz+mask)&(~mask));
                        arg_types = XCDR(arg_types);
                }

                *(char*) (buf+13) = 0xc2;
                *(short*)(buf+14) = (short)byte_size;
        }

        return buf;
}
#endif  /* __i386__ */

DEFUN("ffi-make-callback", Fffi_make_callback, 4, 4, 0, /*
Create dynamic callback and return pointer to it.
*/
      (fun, rtype, argtypes, cctype))
{
        Lisp_Object data;
        Lisp_Object ptr;

        CHECK_INT(cctype);

        data = list3(fun, rtype, argtypes);
        /* Put data as property of the fun, so it(data) wont be GCed */
        Fput(fun, Q_ffi_callback, data);
        ptr = Fmake_ffi_object(Q_pointer, Qnil);
#ifdef __i386__
        XEFFIO(ptr)->fop.ptr = ffi_make_callback_x86(data, XINT(cctype));
#endif /* __i386__ */
        return ptr;
}

void
syms_of_ffi(void)
{
        INIT_LRECORD_IMPLEMENTATION(ffiobject);

        defsymbol(&Q_byte, "byte");
        defsymbol(&Q_unsigned_byte, "unsigned-byte");
        defsymbol(&Q_char, "char");
        defsymbol(&Q_unsigned_char, "unsigned-char");
        defsymbol(&Q_short, "short");
        defsymbol(&Q_unsigned_short, "unsigned-short");
        defsymbol(&Q_int, "int");
        defsymbol(&Q_unsigned_int, "unsigned-int");
        defsymbol(&Q_long, "long");
        defsymbol(&Q_unsigned_long, "unsigned-long");
        defsymbol(&Q_float, "float");
        defsymbol(&Q_double, "double");
        defsymbol(&Q_void, "void");
        defsymbol(&Q_pointer, "pointer");
        defsymbol(&Q_struct, "struct");
        defsymbol(&Q_union, "union");
        defsymbol(&Q_array, "array");
        defsymbol(&Q_function, "function");
        defsymbol(&Q_c_string, "c-string");
        defsymbol(&Q_c_data, "c-data");

        defsymbol(&Qffiobjectp, "ffiobjectp");

        defsymbol(&Qffi_translate_to_foreign, "ffi-translate-to-foreign");
        defsymbol(&Qffi_translate_from_foreign, "ffi-translate-from-foreign");

        defsymbol(&Q_ffi_callback, "ffi-callback");

        DEFSUBR(Fffi_basic_type_p);
        DEFSUBR(Fffi_canonicalise_type);
        DEFSUBR(Fffi_size_of_type);
        DEFSUBR(Fmake_ffi_object);
        DEFSUBR(Fffi_object_p);
        DEFSUBR(Fffi_make_pointer);
        DEFSUBR(Fffi_object_address);
        DEFSUBR(Fffi_object_canonical_type);
        DEFSUBR(Fffi_object_type);
        DEFSUBR(Fffi_object_size);
        DEFSUBR(Fffi_set_storage_size);
        DEFSUBR(Fffi_set_object_type);
        DEFSUBR(Fffi_fetch);
        DEFSUBR(Fffi_aref);
        DEFSUBR(Fffi_store);
        DEFSUBR(Fffi_aset);
        DEFSUBR(Fffi_address_of);
        DEFSUBR(Fffi_type_alignment);
        DEFSUBR(Fffi_slot_offset);
        DEFSUBR(Fffi_load_library);
        DEFSUBR(Fffi_bind);
        DEFSUBR(Fffi_dlerror);
        DEFSUBR(Fffi_defun);
        DEFSUBR(Fffi_call_function);

        DEFSUBR(Fffi_lisp_object_to_pointer);
        DEFSUBR(Fffi_pointer_to_lisp_object);
        DEFSUBR(Fffi_plist);

#ifdef EF_USE_ASYNEQ
        DEFSUBR(Fffi_call_functionX);
        defsymbol(&Qffi_jobp, "ffi-job-p");
#endif

        DEFSUBR(Fx_device_display);

        DEFSUBR(Fffi_make_callback);
}

void
reinit_vars_of_ffi(void)
{
        staticpro_nodump(&Vffi_all_objects);
        Vffi_all_objects = make_weak_list(WEAK_LIST_SIMPLE);
}

void
vars_of_ffi(void)
{
        reinit_vars_of_ffi();

        DEFVAR_LISP("ffi-named-types", &Vffi_named_types        /*
Alist of named FFI types with elements of the form (NAME . FFI-TYPE).
                                                 */ );
        Vffi_named_types = Qnil;

        DEFVAR_LISP("ffi-loaded-libraries", &Vffi_loaded_libraries /*
Alist of loaded libraries with elements of the form (LIB-NAME . FFIO).
                                                 */ );
        Vffi_loaded_libraries = Qnil;

        DEFVAR_LISP("ffi-type-checker", &Vffi_type_checker /*
Function to call when the validity of an FFI type shall be checked.
                                                           */ );
        Vffi_type_checker = intern("ffi-type-p");
}