Class
Description
A representation of a C function
Examples
‘strcpy’
@libc = Fiddle.dlopen "/lib/libc.so.6" #=> #<Fiddle::Handle:0x00000001d7a8d8> f = Fiddle::Function.new( @libc['strcpy'], [Fiddle::TYPE_VOIDP, Fiddle::TYPE_VOIDP], Fiddle::TYPE_VOIDP) #=> #<Fiddle::Function:0x00000001d8ee00> buff = "000" #=> "000" str = f.call(buff, "123") #=> #<Fiddle::Pointer:0x00000001d0c380 ptr=0x000000018a21b8 size=0 free=0x00000000000000> str.to_s => "123"
ABI check
@libc = Fiddle.dlopen "/lib/libc.so.6" #=> #<Fiddle::Handle:0x00000001d7a8d8> f = Fiddle::Function.new(@libc['strcpy'], [TYPE_VOIDP, TYPE_VOIDP], TYPE_VOIDP) #=> #<Fiddle::Function:0x00000001d8ee00> f.abi == Fiddle::Function::DEFAULT #=> true
Constants
Attributes
Read
The address of this function
Read
The name of this function
Class Methods
ext/fiddle/function.c
View on GitHub
static VALUE
initialize(int argc, VALUE argv[], VALUE self)
{
ffi_cif * cif;
ffi_type **arg_types, *rtype;
ffi_status result;
VALUE ptr, args, ret_type, abi, kwds, ary;
int i, len;
int nabi;
void *cfunc;
rb_scan_args(argc, argv, "31:", &ptr, &args, &ret_type, &abi, &kwds);
ptr = rb_Integer(ptr);
cfunc = NUM2PTR(ptr);
PTR2NUM(cfunc);
nabi = NIL_P(abi) ? FFI_DEFAULT_ABI : NUM2INT(abi);
abi = INT2FIX(nabi);
i = NUM2INT(ret_type);
rtype = INT2FFI_TYPE(i);
ret_type = INT2FIX(i);
Check_Type(args, T_ARRAY);
len = RARRAY_LENINT(args);
Check_Max_Args("args", len);
ary = rb_ary_subseq(args, 0, len);
for (i = 0; i < RARRAY_LEN(args); i++) {
VALUE a = RARRAY_PTR(args)[i];
int type = NUM2INT(a);
(void)INT2FFI_TYPE(type); /* raise */
if (INT2FIX(type) != a) rb_ary_store(ary, i, INT2FIX(type));
}
OBJ_FREEZE(ary);
rb_iv_set(self, "@ptr", ptr);
rb_iv_set(self, "@args", args);
rb_iv_set(self, "@return_type", ret_type);
rb_iv_set(self, "@abi", abi);
if (!NIL_P(kwds)) rb_hash_foreach(kwds, parse_keyword_arg_i, self);
TypedData_Get_Struct(self, ffi_cif, &function_data_type, cif);
arg_types = xcalloc(len + 1, sizeof(ffi_type *));
for (i = 0; i < RARRAY_LEN(args); i++) {
int type = NUM2INT(RARRAY_AREF(args, i));
arg_types[i] = INT2FFI_TYPE(type);
}
arg_types[len] = NULL;
result = ffi_prep_cif(cif, nabi, len, rtype, arg_types);
if (result)
rb_raise(rb_eRuntimeError, "error creating CIF %d", result);
return self;
}
Constructs a Function
object.
-
ptr
is a referenced function, of aFiddle::Handle
-
args
is an Array of arguments, passed to theptr
function -
ret_type
is the return type of the function -
abi
is the ABI of the function
Instance Methods
ext/fiddle/function.c
View on GitHub
static VALUE
function_call(int argc, VALUE argv[], VALUE self)
{
struct nogvl_ffi_call_args args = { 0 };
fiddle_generic *generic_args;
VALUE cfunc, types, cPointer;
int i;
VALUE alloc_buffer = 0;
cfunc = rb_iv_get(self, "@ptr");
types = rb_iv_get(self, "@args");
cPointer = rb_const_get(mFiddle, rb_intern("Pointer"));
Check_Max_Args("number of arguments", argc);
if (argc != (i = RARRAY_LENINT(types))) {
rb_error_arity(argc, i, i);
}
TypedData_Get_Struct(self, ffi_cif, &function_data_type, args.cif);
if (rb_safe_level() >= 1) {
for (i = 0; i < argc; i++) {
VALUE src = argv[i];
if (OBJ_TAINTED(src)) {
rb_raise(rb_eSecurityError, "tainted parameter not allowed");
}
}
}
generic_args = ALLOCV(alloc_buffer,
(size_t)(argc + 1) * sizeof(void *) + (size_t)argc * sizeof(fiddle_generic));
args.values = (void **)((char *)generic_args +
(size_t)argc * sizeof(fiddle_generic));
for (i = 0; i < argc; i++) {
VALUE type = RARRAY_AREF(types, i);
VALUE src = argv[i];
int argtype = FIX2INT(type);
if (argtype == TYPE_VOIDP) {
if(NIL_P(src)) {
src = INT2FIX(0);
} else if(cPointer != CLASS_OF(src)) {
src = rb_funcall(cPointer, rb_intern("[]"), 1, src);
}
src = rb_Integer(src);
}
VALUE2GENERIC(argtype, src, &generic_args[i]);
args.values[i] = (void *)&generic_args[i];
}
args.values[argc] = NULL;
args.fn = NUM2PTR(cfunc);
(void)rb_thread_call_without_gvl(nogvl_ffi_call, &args, 0, 0);
rb_funcall(mFiddle, rb_intern("last_error="), 1, INT2NUM(errno));
#if defined(_WIN32)
rb_funcall(mFiddle, rb_intern("win32_last_error="), 1, INT2NUM(errno));
#endif
ALLOCV_END(alloc_buffer);
return GENERIC2VALUE(rb_iv_get(self, "@return_type"), args.retval);
}
Calls the constructed Function
, with args
. Caller must ensure the underlying function is called in a thread-safe manner if running in a multi-threaded process.
For an example see Fiddle::Function
#
ext/fiddle/lib/fiddle/function.rb
View on GitHub
# File tmp/rubies/ruby-2.4.10/ext/fiddle/lib/fiddle/function.rb, line 14
def to_i
ptr.to_i
end
The integer memory location of this function