Does this actually reflect reality?

A task_set_name RPC has been added to GNU Mach. Before, the Mach debugger looked for arg[0] on the stack using ugly heuristics (see gnumach/i386/i386/db_interface.c, looks_like_command...). Now we can let exec simply set the name and record it in task_t. After adding the RPC, glibc needs to be recompiled against the updated mach.defs to get access to it from userland, and exec would probably call it from hurd/exec/exec.c, do_exec(). Also see the discussion on translate fd or port to file name.