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Class: Fiddle::Handle

Relationships & Source Files
Inherits: Object
Defined in: ext/fiddle/handle.c,
ext/fiddle/lib/fiddle/ffi_backend.rb

Overview

The Handle is the manner to access the dynamic library

Example

Setup

libc_so = "/lib64/libc.so.6"
#=> "/lib64/libc.so.6"
@handle = Fiddle::Handle.new(libc_so)
#=> #<Fiddle::Handle:0x00000000d69ef8>

Setup, with flags

libc_so = "/lib64/libc.so.6"
#=> "/lib64/libc.so.6"
@handle = Fiddle::Handle.new(libc_so, Fiddle::RTLD_LAZY | Fiddle::RTLD_GLOBAL)
#=> #<Fiddle::Handle:0x00000000d69ef8>

See RTLD_LAZY and RTLD_GLOBAL

Addresses to symbols

strcpy_addr = @handle['strcpy']
#=> 140062278451968

or

strcpy_addr = @handle.sym('strcpy')
#=> 140062278451968

Constant Summary

  • DEFAULT =

    A predefined pseudo-handle of RTLD_DEFAULT

    Which will find the first occurrence of the desired symbol using the default library search order

    # File 'ext/fiddle/handle.c', line 545 
    new
  • NEXT =

    A predefined pseudo-handle of RTLD_NEXT

    Which will find the next occurrence of a function in the search order after the current library.

    # File 'ext/fiddle/handle.c', line 536 
    predefined_fiddle_handle(RTLD_NEXT)
  • RTLD_GLOBAL =

    :Handle flag.

    The symbols defined by this library will be made available for symbol resolution of subsequently loaded libraries.

    # File 'ext/fiddle/handle.c', line 554 
    FFI::DynamicLibrary::RTLD_GLOBAL
  • RTLD_LAZY =

    :Handle flag.

    Perform lazy binding. Only resolve symbols as the code that references them is executed. If the symbol is never referenced, then it is never resolved. (Lazy binding is only performed for function references; references to variables are always immediately bound when the library is loaded.)

    # File 'ext/fiddle/handle.c', line 566 
    FFI::DynamicLibrary::RTLD_LAZY
  • RTLD_NOW =

    :Handle flag.

    If this value is specified or the environment variable LD_BIND_NOW is set to a nonempty string, all undefined symbols in the library are resolved before Fiddle.dlopen returns. If this cannot be done an error is returned.

    # File 'ext/fiddle/handle.c', line 577 
    FFI::DynamicLibrary::RTLD_NOW

Class Method Summary

Instance Attribute Summary

Instance Method Summary

Constructor Details

.new(library = nil, flags = Fiddle::RTLD_LAZY | Fiddle::RTLD_GLOBAL)

Create a new handler that opens library with flags.

If no library is specified or nil is given, DEFAULT is used, which is the equivalent to RTLD_DEFAULT. See man 3 dlopen for more.

lib = Fiddle::Handle.new

The default is dependent on OS, and provide a handle for all libraries already loaded. For example, in most cases you can use this to access libc functions, or ruby functions like rb_str_new.

[ GitHub ] 

  


# File 'ext/fiddle/handle.c', line 136



static VALUE
rb_fiddle_handle_initialize(int argc, VALUE argv[], VALUE self)
{
    void *ptr;
    struct dl_handle *fiddle_handle;
    VALUE lib, flag;
    char  *clib;
    int   cflag;
    const char *err;

    switch( rb_scan_args(argc, argv, "02", &lib, &flag) ){
      case 0:
	clib = NULL;
	cflag = RTLD_LAZY | RTLD_GLOBAL;
	break;
      case 1:
	clib = NIL_P(lib) ? NULL : StringValueCStr(lib);
	cflag = RTLD_LAZY | RTLD_GLOBAL;
	break;
      case 2:
	clib = NIL_P(lib) ? NULL : StringValueCStr(lib);
	cflag = NUM2INT(flag);
	break;
      default:
	rb_bug("rb_fiddle_handle_new");
    }

#if defined(_WIN32)
    if( !clib ){
	HANDLE rb_libruby_handle(void);
	ptr = rb_libruby_handle();
    }
    else if( STRCASECMP(clib, "libc") == 0
# ifdef RUBY_COREDLL
	     || STRCASECMP(clib, RUBY_COREDLL) == 0
	     || STRCASECMP(clib, RUBY_COREDLL".dll") == 0
# endif
	){
# ifdef _WIN32_WCE
	ptr = dlopen("coredll.dll", cflag);
# else
	(void)cflag;
	ptr = w32_coredll();
# endif
    }
    else
#endif
	ptr = dlopen(clib, cflag);
#if defined(HAVE_DLERROR)
    if( !ptr && (err = dlerror()) ){
	rb_raise(rb_eFiddleDLError, "%s", err);
    }
#else
    if( !ptr ){
	err = dlerror();
	rb_raise(rb_eFiddleDLError, "%s", err);
    }
#endif
    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    if( fiddle_handle->ptr && fiddle_handle->open && fiddle_handle->enable_close ){
	dlclose(fiddle_handle->ptr);
    }
    fiddle_handle->ptr = ptr;
    fiddle_handle->open = 1;
    fiddle_handle->enable_close = 0;

    if( rb_block_given_p() ){
	rb_ensure(rb_yield, self, rb_fiddle_handle_close, self);
    }

    return Qnil;
}


  






  

  

    #initialize(libname = nil, flags = RTLD_LAZY | RTLD_GLOBAL)  ⇒ Handle 
  



  

    
  





  


  [ GitHub ]


  

  


# File 'ext/fiddle/lib/fiddle/ffi_backend.rb', line 477



def initialize(libname = nil, flags = RTLD_LAZY | RTLD_GLOBAL)
  begin
    @lib = FFI::DynamicLibrary.open(libname, flags)
  rescue LoadError, RuntimeError # LoadError for JRuby, RuntimeError for TruffleRuby
    raise DLError, "Could not open #{libname}"
  end

  @open = true

  begin
    yield(self)
  ensure
    self.close
  end if block_given?
end


  







Class Method Details



  

    .[](name)      Also known as: .sym
  



  

    

Get the address as an Integer for the function named name.


  



  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 324



static VALUE
rb_fiddle_handle_s_sym(VALUE self, VALUE sym)
{
    return fiddle_handle_sym(RTLD_NEXT, sym);
}


  








  

    

      .[](name)  
      .sym(name)  
    

  



  

    

Alias for .[].


  





  








  

    .sym_defined?(func)  ⇒ Boolean 
  



  

    
  





  


  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 394



static VALUE
rb_fiddle_handle_s_sym_defined(VALUE self, VALUE sym)
{
    fiddle_void_func func;

    func = fiddle_handle_find_func(RTLD_NEXT, sym);

    if( func ) {
	return PTR2NUM(func);
    }
    else {
	return Qnil;
    }
}


  







Instance Attribute Details



  

    #close_enabled?  ⇒ Boolean  (readonly)  



  

    

Returns true if dlclose() will be called when this handle is garbage collected.



See man(3) dlclose() for more info.


  



  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 246



static VALUE
rb_fiddle_handle_close_enabled_p(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);

    if(fiddle_handle->enable_close) return Qtrue;
    return Qfalse;
}


  







Instance Method Details



  

    #[](name)      Also known as: #sym
  



  

    

Get the address as an Integer for the function named name.  The function is searched via dlsym on RTLD_NEXT.



See man(3) dlsym() for more info.


  



  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 294



static VALUE
rb_fiddle_handle_sym(VALUE self, VALUE sym)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    if( ! fiddle_handle->open ){
	rb_raise(rb_eFiddleDLError, "closed handle");
    }

    return fiddle_handle_sym(fiddle_handle->ptr, sym);
}


  








  

    #close  
  



  

    

keeping while its symbols are referred.


  





  
Raises:





  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 70



static VALUE
rb_fiddle_handle_close(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    if(fiddle_handle->open) {
	int ret = dlclose(fiddle_handle->ptr);
	fiddle_handle->open = 0;

	/* Check dlclose for successful return value */
	if(ret) {
#if defined(HAVE_DLERROR)
	    rb_raise(rb_eFiddleDLError, "%s", dlerror());
#else
	    rb_raise(rb_eFiddleDLError, "could not close handle");
#endif
	}
	return INT2NUM(ret);
    }
    rb_raise(rb_eFiddleDLError, "dlclose() called too many times");

    UNREACHABLE;
}


  








  

    #disable_close    



  

    

Disable a call to dlclose() when this handle is garbage collected.


  



  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 229



static VALUE
rb_fiddle_handle_disable_close(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    fiddle_handle->enable_close = 0;
    return Qnil;
}


  








  

    #enable_close    



  

    

Enable a call to dlclose() when this handle is garbage collected.


  



  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 214



static VALUE
rb_fiddle_handle_enable_close(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    fiddle_handle->enable_close = 1;
    return Qnil;
}


  








  

    #file_name    



  

    

Returns the file name of this handle.


  



  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 449



static VALUE
rb_fiddle_handle_file_name(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);

#if defined(HAVE_DLINFO) && defined(HAVE_CONST_RTLD_DI_LINKMAP)
    {
	struct link_map *lm = NULL;
	int res = dlinfo(fiddle_handle->ptr, RTLD_DI_LINKMAP, &lm);
	if (res == 0 && lm != NULL) {
	    return rb_str_new_cstr(lm->l_name);
	}
	else {
#if defined(HAVE_DLERROR)
	    rb_raise(rb_eFiddleDLError, "could not get handle file name: %s", dlerror());
#else
	    rb_raise(rb_eFiddleDLError, "could not get handle file name");
#endif
	}
    }
#elif defined(HAVE_GETMODULEFILENAME)
    {
	char filename[MAX_PATH];
	DWORD res = GetModuleFileName(fiddle_handle->ptr, filename, MAX_PATH);
	if (res == 0) {
	    rb_raise(rb_eFiddleDLError, "could not get handle file name: %s", dlerror());
	}
	return rb_str_new_cstr(filename);
    }
#else
    (void)fiddle_handle;
    return Qnil;
#endif
}


  








  

    

      #[](name)  
      #sym(name)  
    

  



  

    

Alias for #[].


  





  
Raises:


    
  
  • 
    (TypeError)
  
    • 











  

    #sym_defined?(func)  ⇒ Boolean 
  



  

    
  





  
Raises:


    
  
  • 
    (TypeError)
  
    • 





  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 409



static VALUE
rb_fiddle_handle_sym_defined(VALUE self, VALUE sym)
{
    struct dl_handle *fiddle_handle;
    fiddle_void_func func;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    if( ! fiddle_handle->open ){
	rb_raise(rb_eFiddleDLError, "closed handle");
    }

    func = fiddle_handle_find_func(fiddle_handle->ptr, sym);

    if( func ) {
	return PTR2NUM(func);
    }
    else {
	return Qnil;
    }
}


  








  

    #to_i  ⇒ Integer   



  

    

Returns the memory address for this handle.


  



  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 262



static VALUE
rb_fiddle_handle_to_i(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    return PTR2NUM(fiddle_handle->ptr);
}


  








  

    #to_ptr  ⇒ ?   



  

    

Returns the Pointer of this handle.


  



  [ GitHub ]


  

  


# File 'ext/fiddle/handle.c', line 276



static VALUE
rb_fiddle_handle_to_ptr(VALUE self)
{
    struct dl_handle *fiddle_handle;

    TypedData_Get_Struct(self, struct dl_handle, &fiddle_handle_data_type, fiddle_handle);
    return rb_fiddle_ptr_new_wrap(fiddle_handle->ptr, 0, 0, self, 0);
}