Crate findshlibs

findshlibs

Find the set of shared libraries currently loaded in this process with a cross platform API.

The API entry point is the TargetSharedLibrary type and its SharedLibrary::each trait method implementation.

Example

Here is an example program that prints out each shared library that is loaded in the process and the addresses where each of its segments are mapped into memory.

extern crate findshlibs;
use findshlibs::{Segment, SharedLibrary, TargetSharedLibrary};

fn main() {
    TargetSharedLibrary::each(|shlib| {
        println!("{}", shlib.name().to_string_lossy());

        for seg in shlib.segments() {
            println!("    {}: segment {}",
                     seg.actual_virtual_memory_address(shlib),
                     seg.name().to_string_lossy());
        }
    });
}

Supported OSes

These are the OSes that findshlibs currently supports:

• Linux
• macOS

If a platform is not supported then a fallback implementation is used that does nothing. To see if your platform does something at runtime the TARGET_SUPPORTED constant can be used.

Is your OS missing here? Send us a pull request!

Addresses

Shared libraries' addresses can be confusing. They are loaded somewhere in physical memory, but we generally don't care about physical memory addresses, because only the OS can see that address and in userspace we can only access memory through its virtual memory address. But even "virtual memory address" is ambiguous because it isn't clear whether this is the address before or after the loader maps the shared library into memory and performs relocation.

To clarify between these different kinds of addresses, we borrow some terminology from LUL:

• SVMA ("Stated Virtual Memory Address"): this is an address of a symbol (etc) as it is stated in the symbol table, or other metadata, of an object. Such values are typically small and start from zero or thereabouts, unless the object has been prelinked.

• AVMA ("Actual Virtual Memory Address"): this is the address of a symbol (etc) in a running process, that is, once the associated object has been mapped into a process. Such values are typically much larger than SVMAs, since objects can get mapped arbitrarily far along the address space.

• "Bias": the difference between AVMA and SVMA for a given symbol (specifically, AVMA - SVMA). The bias is always an integral number of pages. Once we know the bias for a given object's text section (for example), we can compute the AVMAs of all of its text symbols by adding the bias to their SVMAs.

Modules

linux	Linux-specific implementation of the SharedLibrary trait.
unsupported	The fallback implementation of the SharedLibrary trait that does nothing.

Structs

Avma	Actual virtual memory address.
Bias	Virtual memory bias.
Svma	Stated virtual memory address.

Enums

IterationControl	Control whether iteration over shared libraries should continue or stop.
SharedLibraryId	Represents an ID for a shared library.

Constants

TARGET_SUPPORTED

An indicator if this platform is supported.

Traits

Segment	A mapped segment in a shared library.
SharedLibrary	A trait representing a shared library that is loaded in this process.

Type Definitions

TargetSharedLibrary

The SharedLibrary trait implementation for the target operating system.