Struct plthook::ObjectFile

pub struct ObjectFile { /* fields omitted */ }

An object file loaded in memory.

Please see the top-level documentation for more details.

Implementations

impl ObjectFile

pub fn open_main_program() -> Result<Self>

Load the object for the main program.

pub fn open_file<P: AsRef<Path>>(filename: P) -> Result<Self>

Load an object from a file.

pub unsafe fn open_by_handle(handle: *const c_void) -> Result<Self>

Load a dynamic loaded shared object.

handle is the address of the shared object. This value can be obtained by a function like dlopen.

Safety

This constructor is unsafe because we don’t check that the handle is a valid address.

pub unsafe fn replace(
    &self,
    symbol_name: &str,
    func_address: *const c_void
) -> Result<Replacement<'_>>

Replace the address of a symbol in the PLT section, and returns a reference to the previous entry. When this reference is dropped, the entry is restored to the previous value.

The reference to the previous entry can be used to invoke the original function.

Safety

The caller has to verify that the new address for the symbol is valid.

The function is not thread-safe.

Example

use plthook::ObjectFile;
use std::process;

let pid = process::id();

extern "C" fn broken_getpid() -> libc::pid_t {
    -1
}

let program = ObjectFile::open_main_program().unwrap();
let entry = unsafe {
    program.replace("getpid", broken_getpid as *const _).unwrap()
};

assert_eq!(process::id(), u32::MAX);

drop(entry);
assert_eq!(process::id(), pid);

pub fn symbols(&self) -> impl Iterator<Item = Symbol> + '_

Returns an iterator to get all symbols in the PLT section.

Example

use plthook::ObjectFile;

let object = ObjectFile::open_main_program()?;
for symbol in object.symbols() {
    println!("{:?} {:?}", symbol.func_address, symbol.name);
}

Trait Implementations

impl Drop for ObjectFile

fn drop(&mut self)

Executes the destructor for this type.