getlogin caching and setlogin issues

[Ali Mashtizadeh]

In addition, I couldn't find a reason for sigreturn() to be custom assembly
in i386/amd64/arm/aarch64.

Best,
Ali

On Tue, Apr 3, 2018 at 1:07 PM, Brooks Davis <brooks at freebsd.org> wrote:

> [Ali found this issue while looking at pulling syscalls out of libc.]
>
> getlogin() is a wrapper around _getlogin() which caches the value
> returned and sets a and internal _logname_valid flag.  Some
> implementations of setlogin() clear that flag on return, the arm, mips,
> and riscv ones use the default assembly and do not.  This leaves me two
> questions:
>
> 1) Does this cache make sense?  Sure login rarely changes, but is
> getlogin called frequently in real software?
>
> 2) If the cache makes sense, does clearing the cache belong in
> __sys_setlogin() or should it be done in a C wrapper in setlogin() or
> _setlogin()?  I think it should likely be pulled up to _setlogin().
>
> 3) If yes to 1 and no to 2, do we need to fix arm, mips, and riscv?
>
> -- Brooks