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.

Checked on aarch64-linux-gnu.

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

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This commit is contained in:
Jesse Hathaway 2018-03-27 21:17:59 +00:00 committed by Adhemerval Zanella
parent 8bfd94d0dc
commit cc8a1620eb
2 changed files with 14 additions and 0 deletions

View File

@ -1,3 +1,8 @@
2018-03-27 Jesse Hathaway <jesse@mbuki-mvuki.org>
* sysdeps/unix/sysv/linux/getlogin_r.c (__getlogin_r_loginuid): Return
early when linux sentinel value is set.
2018-03-27 Samuel Thibault <samuel.thibault@ens-lyon.org>
* sysdeps/mach/hurd/bits/posix_opt.h (_POSIX_MEMLOCK): Define.

View File

@ -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;