Re: bash-4-2 issue

[Chet Ramey]

On 1/11/24 10:55 AM, Chet Ramey wrote:
> On 1/11/24 3:46 AM, Sam Kappen via Bug reports for the GNU Bourne Again 
> SHell wrote:
>
> > Thanks.
> > I am using a Linux host with kernel version 4.x for cross building.
> > It looks like autoconf is not defining the "PGRP_PIPE" macro variable as
> > there is no check for linux kernel version 4.
>
> The uname check works, and the current version just sets it unconditionally
> for linux kernel versions that aren't 1 or 2. It's probably time so see why
> the BASH_SYS_PGRP_SYNC autoconf test isn't working, since the uname check
> isn't appropriate for cross-building.

There's nothing actually wrong with that test; the error Grisha sees is
happening because the setpgid() is attempting to use a process group that
really doesn't exist, not the zombie process pid that the test checks.

Depending on how the timing goes, the wait for /usr/bin/true in the DEBUG
trap command for the second pipeline element will reap the first pipeline
process (the pgrp leader) before the second pipeline element has a chance
to try and set its process group.

The PGRP_PIPE define makes all the pipeline elements wait to execute until
they've all been created and set their pgrp, so it prevents this from
happening.


--
``The lyf so short, the craft so long to lerne.'' - Chaucer
                 ``Ars longa, vita brevis'' - Hippocrates
Chet Ramey, UTech, CWRU    chet@case.edu    http://tiswww.cwru.edu/~chet/

OpenPGP_signature.asc
Description: OpenPGP digital signature