lje.func

Function inspection, spoofing, and stealth utilities.

Functions

`lje.func.spoof(spoof_fn, target_fn)`

Makes target_fn appear as spoof_fn in debug introspection (e.g. debug.getinfo).

The spoof is recorded globally. Each function can only participate in one spoof relationship at a time.

Parameters

Name	Type	Description
`spoof_fn`	`function`	The Lua function whose debug info will be reported. Must be a Lua function, not a C function.
`target_fn`	`function`	The function that will appear as `spoof_fn` when inspected.

Errors

Argument 1 must be a Lua function (not a C function).

`lje.func.is_spoofed(fn)`

Checks whether fn is currently being used as a spoof target.

Parameters

Name	Type	Description
`fn`	`function`	The function to check.

Returns

Type	Description
`boolean`	`true` if the function is a spoof target, `false` otherwise.
`function?`	If spoofed, the original function is also returned as a second value.

`lje.func.mark_special(fn)`

Note: You shouldn't need to use this unless you know what you are doing!

Marks a Lua function as a special (internal) frame.

Special frames are hidden from stack introspection unless lje.env.show_special_frames is enabled. Automatically applied to callbacks registered with LJE (e.g. lje.util.set_push_string_callback).

Parameters

Name	Type	Description
`fn`	`function`	Must be a Lua function, not a C function.

Errors

Argument 1 must be a Lua function (not a C function).

`lje.func.compile(source)`

Compiles a Lua string into a function without executing it. If a global environment is set via lje.env.set, it is applied to the compiled function automatically. Returns nil on compilation failure.

Parameters

Name	Type	Description
`source`	`string`	Lua source code to compile.

Returns

Type	Description
`function \| nil`	The compiled function, or `nil` if compilation failed.

`lje.func.hide_caller(fn)`

Hides fn from appearing as a caller in stack traces.

Parameters

Name	Type	Description
`fn`	`function`	The function to hide from stack traces.

`lje.func.type(fn)`

Returns the internal LuaJIT fast function ID (ffid) of a function.

0 means a Lua function
1 means a C function
Anything else is the unique ID of a fast function.

Parameters

Name	Type	Description
`fn`	`function`	The function to inspect.

Returns

Type	Description
`number`	The `ffid` value. `0` for regular Lua functions.