Function tango_bench::linux::patch_pie_binary_if_needed

pub fn patch_pie_binary_if_needed(
    path: impl AsRef<Path>,
) -> Result<Option<PathBuf>, Error>

Patches executable file for new version of glibc dynamic loader

After glibc 2.29 on linux dlopen is explicitly denying loading PIE executables as a shared library. The following error might appear:

dlopen error: cannot dynamically load position-independent executable

From 2.29 dynamic loader throws an error if DF_1_PIE flag is set in DT_FLAG_1 tag on the PT_DYNAMIC section. Although the loading of executable files as a shared library was never an intended use case, through the years some applications adopted this technique and it is very convenient in the context of paired benchmarking.

Following method check if this flag is set and patch binary at runtime (writing patched version in a different file). As far as I am aware this is safe modification because DF_1_PIE is purely informational and doesn’t changle the dynamic linking process in any way. Theoretically in the future this modification could prevent ASLR ramndomization on the OS level which is irrelevant for benchmark executables.