Re: [PATCH] getlogin_r: return early when linux sentinel value is set

[Adhemerval Zanella <adhemerval.zanella@linaro.org>]

On 22/03/2018 05:27, Jesse Hathaway wrote:
> On Tue, Mar 20, 2018 at 1:30 PM, Andreas Schwab <schwab@linux-m68k.org> wrote:
>> Depends on whether you want the linux __getlogin_r to fall back to the
>> generic __getlogin_r.
> 
> Thanks, updated patch below:
> 
> From 04a50b5ee857aa33e1527d70f0676b6daf5a036c Mon Sep 17 00:00:00 2001
> From: Jesse Hathaway <jesse@mbuki-mvuki.org>
> Date: Fri, 16 Mar 2018 10:46:50 -0500
> Subject: [PATCH] getlogin_r: return early when linux sentinel value is set
> 
> When there is no login uid Linux sets /proc/self/loginid to the sentinel
> value of, (uid_t) - 1. If this is set we can return early and avoid
> needlessly looking up the sentinel value in any configured nss
> databases.

LGTM with CL bit fixed below.  Do you need someone to push it for you?

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

> 
> diff --git a/ChangeLog b/ChangeLog
> index 3399e567b8..1ceff1c094 100644
> --- a/ChangeLog
> +++ b/ChangeLog
> @@ -1,3 +1,8 @@
> +2018-03-20  Jesse Hathaway  <jesse@mbuki-mvuki.org>  (tiny change)
> +
> + * sysdeps/unix/sysv/linux/getlogin_r.c (__getlogin_r_loginuid): return early
> + when linux sentinel value is set.

It should contain a tab first and respect the maximum line size of 78, as:

        * sysdeps/unix/sysv/linux/getlogin_r.c (__getlogin_r_loginuid): Return
        early when linux sentinel value is set.


> +
>  2018-03-20  Samuel Thibault  <samuel.thibault@ens-lyon.org>
> 
>   * manual/errno.texi (EOWNERDEAD, ENOTRECOVERABLE): Remove errno
> diff --git a/sysdeps/unix/sysv/linux/getlogin_r.c
> b/sysdeps/unix/sysv/linux/getlogin_r.c
> index 73ea14c8f9..1f90c1ca2d 100644
> --- a/sysdeps/unix/sysv/linux/getlogin_r.c
> +++ b/sysdeps/unix/sysv/linux/getlogin_r.c
> @@ -55,6 +55,15 @@ __getlogin_r_loginuid (char *name, size_t namesize)
>     endp == uidbuf || *endp != '\0'))
>      return -1;
> 
> +  /* If there is no login uid, linux sets /proc/self/loginid to the sentinel
> +     value of, (uid_t) - 1, so check if that value is set and return early to
> +     avoid making unneeded nss lookups. */
> +  if (uid == (uid_t) - 1)
> +    {
> +      __set_errno (ENXIO);
> +      return ENXIO;
> +    }
> +
>    struct passwd pwd;
>    struct passwd *tpwd;
>    int result = 0;
>