Re: bash process substitution does not work in FreeBSD 5.2.1 with devfs(5)

[Reinhard Speyerer]

Chet Ramey wrote:
> Reinhard Speyerer wrote:
[...]
> > Repeat-By:
> >     # Check that devfs(5) is mounted on /dev and execute a command
> >     # that uses process substitution.
> >     $ mount | grep devfs
> >     devfs on /dev (devfs, local)
> >     $ diff <(cat /etc/group)  <(cat /etc/group)
> >     diff: /dev/fd/63: No such file or directory
> >     diff: /dev/fd/62: No such file or directory
> >     $ ls /dev/fd
> >     0    1    2
[...]
> Upgrade.  Bash-3.0 tests for this at configure time.
>
> Chet

The above results were obtained with
Bash Version: 3.0
Patch Level: 0
Release Status: release
and
FreeBSD 5.2.1.

The cause of the problem seems to be that FreeBSD changed from a static /dev 
hierarchy in FreeBSD 4.x to a dynamically updated one via a devfs mount on /dev
and not updating /dev/fd entries accordingly when file descriptors are opened
as can be seen by the following example:

freebsd44$ sh
$ exec 9</dev/null && test -r /dev/fd/9
$ echo $?
0
$

freebsd521$ sh
$ ls -l /dev/fd
total 0
crw-rw-rw-  1 root  wheel   22,   0 Oct  6 20:57 0
crw-rw-rw-  1 root  wheel   22,   1 Oct  6 20:57 1
crw-rw-rw-  1 root  wheel   22,   2 Oct  6 20:57 2
$ exec 9</dev/null && test -r /dev/fd/9
$ echo $?
1
$ ls -l /dev/fd
total 0
crw-rw-rw-  1 root  wheel   22,   0 Oct  6 20:57 0
crw-rw-rw-  1 root  wheel   22,   1 Oct  6 20:57 1
crw-rw-rw-  1 root  wheel   22,   2 Oct  6 20:57 2
$

The bash configure script should probably be extended to include code similar to 
the above in addition to the test -r /dev/fd/0 check when setting bash_cv_dev_fd.

Reinhard