[debbugs-tracker] bug#26371: closed ([PATCH 0/1] tty: do not provide conflicting information)

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Your message dated Wed, 5 Apr 2017 11:40:15 -0700
with message-id <address@hidden>
and subject line Re: bug#26371: [PATCH 0/1] tty: do not provide conflicting 
information
has caused the debbugs.gnu.org bug report #26371,
regarding [PATCH 0/1] tty: do not provide conflicting information
to be marked as done.

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26371: http://debbugs.gnu.org/cgi/bugreport.cgi?bug=26371
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> --- Begin Message ---
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> Subject: 
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> [PATCH 0/1] tty: do not provide conflicting information
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> Date: 
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> Wed,  5 Apr 2017 16:44:40 +0200
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> Hi guys,
>
> In case the current file descriptor is a tty but ttyname{_r}() fails to retrieve
> the device path tty would falsely report "not a tty" but return EXIT_SUCCESS.
> This is confusing. Instead, let's first check whether the fd refers to a tty and
> if not report "not a tty" and exit with error. In all other cases, we should
> report "is a tty but failed to determine the device path" and exit with success.
> This is much clearer. Depending on the platform the user can then decide how to
> proceed, e.g. by looking at /proc/self/fd/0 for Linux or somewhere else on other
> platforms.
>
> This becomes especially important when we deal with Linux namespaces where this
> case can regularly happen should a new devpts instance be mounted in the
> namespace but the fd still refers to a pts device from another devpts instance
> in another mount namespace.
>
> I added Signed-off-by line but I'm not completely sure if this is used in
> cureutils. If not, just drop it. :)
>
> Christian
>
> Christian Brauner (1):
>   tty: do not provide conflicting information
>
>  src/tty.c | 12 ++++++++++--
>  1 file changed, 10 insertions(+), 2 deletions(-)
>
> -- 
> 2.11.0
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> --- End Message ---

--- Begin Message --- Subject: Re: bug#26371: [PATCH 0/1] tty: do not provide conflicting information Date: Wed, 5 Apr 2017 11:40:15 -0700 User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.8.0 Thanks for the bug report. The situation you describe seems to be a platform that does not conform to POSIX, since POSIX doesn't allow for isatty to succeed but ttyname to fail. So I expect you'll run into problems other than with the tty program, as other software will make the same assumptions that tty is making.

That being said, tty could do a better job about the situation. I installed the attached somewhat-more-ambitious patch, so that tty will do more-extensive checking of the results of isatty and/or ttyname (and so that it never needs to call both functions and worry about whether their results are consistent :-). Please give it a try on your platform.

0001-tty-handle-misconfigured-namespaces.patch
Description: Source code patch

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