make strace print EUID

Question

I'm trying to debug a permission problem, but I'm having trouble finding out with which EUID the application is being executed at the moment of the error.

Is there a way to make strace print the effective user ID?

Answer 1

strace can't do that.

strace uses a kernel's feature known as ptrace.

setuid is always ignored if a process is ptraced, even if root is ptracing to avoid a root exploit known as myptrace.c.