problems with devfs amd /dev/fd/

[Doug White]

On Tue, 4 Jan 2005, Jose M Rodriguez wrote:

> Hi,
>
> trying to import foomatic-rip, I found great changes under /dev/fd/
> going from RELENG_4 to RELENG_5.
>
> Seems that /dev/fd/3 is used by several pipe construct like foomatic-rip
> to get a free backwards error channel.
>
> Digging a bit, I found that now, I need mount fdescfs to get this.  I
> think this is not well documented in release notes.

Nothing in the FreeBSD base system depends on /dev/fd. foomatic-rip a
third-party program. It would be appropriate for the port to print a
message reminding the user to mount fdescfs if they plan to use this
application, but not appropriate to enable it by default just for this one
port.

> Also, seems that support /dev/fd/3 in devfs may be a good idea.  Add a
> sysctl to control how many /dev/fd/n devfs create will be even better.

fdesc is populated automatically based on the calling program. If the
program has file descriptor 3 open then /dev/fd/3 will be available.
Likewise, if it is closed, /dev/fd/3 will not exist.

-- 
Doug White                    |  FreeBSD: The Power to Serve
dwhite at gumbysoft.com          |  www.FreeBSD.org