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| author | Jesse Hathaway <jesse@mbuki-mvuki.org> | 2018-03-27 21:17:59 +0000 |
|---|---|---|
| committer | Fangrui Song <i@maskray.me> | 2021-08-27 16:22:10 -0700 |
| commit | dadc309087c7acab517ed3e42546aa859ae9fb45 (patch) | |
| tree | f1402a3b8fdf60cd0cc40623a54c0d9990305ddf | |
| parent | da41ab8923709c52f4db76c8b5f5ea756f279359 (diff) | |
| download | glibc-dadc309087c7acab517ed3e42546aa859ae9fb45.zip glibc-dadc309087c7acab517ed3e42546aa859ae9fb45.tar.gz glibc-dadc309087c7acab517ed3e42546aa859ae9fb45.tar.bz2 | |
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>
(cherry picked from commit cc8a1620eb97ccddd337d157263c13c57b39ab71)
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | sysdeps/unix/sysv/linux/getlogin_r.c | 9 |
2 files changed, 14 insertions, 0 deletions
@@ -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 Andreas Schwab <schwab@suse.de> [BZ #23005] diff --git a/sysdeps/unix/sysv/linux/getlogin_r.c b/sysdeps/unix/sysv/linux/getlogin_r.c index 84c51d0..7a814ea 100644 --- a/sysdeps/unix/sysv/linux/getlogin_r.c +++ b/sysdeps/unix/sysv/linux/getlogin_r.c @@ -54,6 +54,15 @@ __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; + } + size_t buflen = 1024; char *buf = alloca (buflen); bool use_malloc = false; |