From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: libc-alpha@sourceware.org
Subject: Re: [PATCH] getlogin_r: return early when linux sentinel value is set
Date: Tue, 20 Mar 2018 08:00:00 -0000 [thread overview]
Message-ID: <73b04097-ef36-b597-4f7c-2e73c6eb9fa3@linaro.org> (raw)
In-Reply-To: <CANSNSoWLXfsYq6kP0niyP8r25S=S1uTKN=+46xnC_SPLBmKXhQ@mail.gmail.com>
On 17/03/2018 00:18, Jesse Hathaway wrote:
> When there is no login uid Linux sets /proc/self/loginid to the sentinel
> value of 4294967295. If this is set we can return early and avoid
> needlessly looking up the sentinel value in any configured nss
> databases.
The change is short enough so I think it won't require a copyright
assignment. However it does require a ChangeLog entry, could you please
resend the patch with a proper one?
>
> diff --git a/sysdeps/unix/sysv/linux/getlogin_r.c
> b/sysdeps/unix/sysv/linux/getlogin_r.c
> index 73ea14c8f9..43f55a2188 100644
> --- a/sysdeps/unix/sysv/linux/getlogin_r.c
> +++ b/sysdeps/unix/sysv/linux/getlogin_r.c
> @@ -55,6 +55,12 @@ __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 4294967295, so check if the value is set and return early to
> + avoid making unneeded nss lookups. */
> + if (uid == 4294967295)
> + return ENXIO;
I prefer to just use either (int)-1 or just 0xffffffff. Also,
__getlogin_r_loginuid should set errno itself as for ERANGE instead
of just return its value (errno won't be set in this case and I think
it got it wrong for ENOMEM in this case).
> +
> struct passwd pwd;
> struct passwd *tpwd;
> int result = 0;
>
next prev parent reply other threads:[~2018-03-20 8:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-16 16:18 Jesse Hathaway
2018-03-19 15:03 ` Jesse Hathaway
2018-03-20 8:00 ` Adhemerval Zanella [this message]
2018-03-20 9:05 ` Andreas Schwab
2018-03-20 17:52 ` Jesse Hathaway
2018-03-20 18:30 ` Andreas Schwab
2018-03-21 21:28 ` Jesse Hathaway
2018-03-22 6:14 ` Adhemerval Zanella
2018-03-22 13:49 ` Jesse Hathaway
2018-03-22 17:35 ` Andreas Schwab
2018-03-22 19:30 ` Jesse Hathaway
2018-03-26 14:22 ` Jesse Hathaway
2018-03-26 16:30 ` Adhemerval Zanella
2018-03-28 0:37 ` Adhemerval Zanella
2018-04-03 10:46 ` Florian Weimer
2018-04-03 11:41 ` Adhemerval Zanella
2018-04-03 11:45 ` Florian Weimer
2018-04-03 11:53 ` Adhemerval Zanella
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