如何在提供库的地址时获取共享库中符号的地址？

Question

I am learning about working with shared libraries in C/C++ on Linux. I encountered a little problem that I don't know how to solve.

Let's say I have a shared library and an executable. However I don't know the library's name or file location (so I can't dlopen it). I can only find the address range where the library is mapped into my executable's memory.

Is there a way to programmatically get either the handle of the library (something like handle = dlopen(library_address) ) or offset of a symbol within the library (something like address = dlsym(library_address, symbol_name) )?

Thank you for your answers.

Answer 1

If you knew the library's name, you could just call dlopen again.

From the man page :

If the same shared object is loaded again with dlopen() , the same object handle is returned.

To discover the loaded modules, you can use dl_iterate_phdr() .

You can also use dladdr() to inquire about a specific address.