Class: Fiddle::Handle
Relationships & Source Files | |
Inherits: | Object |
Defined in: | ext/fiddle/handle.c |
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
predefined_fiddle_handle(RTLD_DEFAULT)
-
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.
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.
rtld Fiddle
-
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.)
rtld Fiddle
-
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.
rtld Fiddle
Class Method Summary
-
.[](name)
(also: .sym)
Get the address as an Integer for the function named
name
. -
.new(library = nil, flags = Fiddle::RTLD_LAZY | Fiddle::RTLD_GLOBAL)
constructor
Create a new handler that opens
library
withflags
. -
.sym(name)
Alias for .[].
Instance Attribute Summary
-
#close_enabled? ⇒ Boolean
readonly
Returns
true
if dlclose() will be called when this handle is garbage collected.
Instance Method Summary
-
#[](name)
(also: #sym)
Get the address as an Integer for the function named
name
. - #close
-
#disable_close
Disable a call to dlclose() when this handle is garbage collected.
-
#enable_close
Enable a call to dlclose() when this handle is garbage collected.
-
#sym(name)
Alias for #[].
-
#to_i ⇒ Integer
Returns the memory address for this handle.
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
.
Class Method Details
.[](name) Also known as: .sym
Get the address as an Integer for the function named name
.
.[](name)
.sym(name)
Alias for .[].
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.
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.
#close
#disable_close
Disable a call to dlclose() when this handle is garbage collected.
#enable_close
Enable a call to dlclose() when this handle is garbage collected.
#[](name)
#sym(name)
Alias for #[].
#to_i ⇒ Integer
Returns the memory address for this handle.