lkml.org 
[lkml]   [2016]   [Apr]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH 01/13] devpts: Teach /dev/ptmx to find the associated devpts via path lookup
From
Date
On April 9, 2016 6:09:09 AM PDT, One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> wrote:
>
>> If anyone has a better idea on how userspace should connect the
>master
>> pty file descriptor the slave file descriptor, I would be willing to
>> implement that instead.
>
>If we are willing to go away from the existing mess of a tty interface
>inflicted on us by BSD and then mashed up by POSIX then a syscall of
>
> int err = ptypair(int fd[2], int perms, int flags);
>
>[where flags is the O_ ones we usually need to cover (CLOEXEC etc) and
>maybe even some kind of "private" flag to say don't even expose it via
>devpts).
>
>would do remarkably sane things to the majoirty of use cases as it
>breaks
>the dependence on grantpt and also the historic screwup that pty pairs
>aren't allocated atomically with both file handles returned as pipe()
>does.
>
>Alan

We don't even need to do that if we'd be willing to change the user space interface... if we could rely on the POSIX interface then posix_openpt() could simply open /dev/pts/ptmx and everything would just work.

The trick here is how to make it work in the presence of some extremely bad practices in existing userspace.
--
Sent from my Android device with K-9 Mail. Please excuse brevity and formatting.

\
 
 \ /
  Last update: 2016-04-09 16:41    [W:0.253 / U:1.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site