:: Re: [DNG] Printing -- now a permiss…
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Author: Hendrik Boom
Date:  
To: dng
Subject: Re: [DNG] Printing -- now a permissions problem
On Mon, Oct 19, 2015 at 04:05:37PM +0200, Didier Kryn wrote:
> Le 19/10/2015 15:24, Hendrik Boom a écrit :
> >On Mon, Oct 05, 2015 at 05:13:40PM -0400, Hendrik Boom wrote:
> >>On Mon, Oct 05, 2015 at 09:47:02PM +0200, Riccardo Boninsegna wrote:
> >>>On Mon, Oct 5, 2015 at 9:12 PM, Hendrik Boom <hendrik@???> wrote:
> >>>>I installed lpr, and it did take a lot of cups off. Do I really need cups?
> >>>Nope, especially with a Brother that's very LPR-friendly!
> >>>As you found out, cups-bsd is just a port of LPR programs to CUPS.
> >>>
> >>>>But I still don't know how to specify my network printer.
> >>>I'm not familiar at all with LPR, but I know a printcap entry for the
> >>>printer is created (if it's currently connected via USB) by the
> >>>driver's postinst somewhere under /opt/Brother; according to the
> >>>printcap manpage, you'd have to edit the "lp" option -- the
> >>>description says "local printer device, or port@host for remote"!
> >>Presumeably that would be port 515 at whatever the IP number for the
> >>printer is. Will try that wen I'm home near the priniter again.
> >>
> >>And what's there in the way of termcap is a shell script
> >>/opt/brother/Printers/hl3170cdw/inf/setupPrintcapij that creates a
> >>termcap. I hope it will get executed at the right time. At bootup,
> >>perhaps?
> >>
> >>I'll see when I'm home again.
> >Hand-edited /etc/termcap:
> >root@notlookedfor:/home/hendrik# cat /etc/printcap
> >HL3170CDW:\
> >         :mx=0:\
> >         :sd=/var/spool/lpd/hl3170cdw:\
> >         :sh:\
> >         :lp=515@172.25.1.122:\
> >         :if=/opt/brother/Printers/hl3170cdw/lpd/filterhl3170cdw:
> >root@notlookedfor:/home/hendrik#

> >
> >Now I get
> >
> >hendrik@notlookedfor:~$ lpr -h -PHL3170CDW Documents/math/Librationism=1407.3877v3.ps
> >lpr: cannot open /var/spool/lpd/hl3170cdw/.seq: Permission denied
> >hendrik@notlookedfor:~$
> >
> >This happens even if I run as root:
> >
> >root@notlookedfor:/home/hendrik# lpr -h -PHL3170CDW Documents/math/Librationism=1407.3877v3.ps
> >lpr: cannot open /var/spool/lpd/hl3170cdw/.seq: Permission denied
> >root@notlookedfor:/home/hendrik#
> >
> >That directory is owned by the lp daemon:
> >
> >oot@notlookedfor:/home/hendrik# ls -al /var/spool/lpd/hl3170cdwtotal 8
> >drwx------ 2 daemon lp   4096 Oct  5 14:40 .
> >drwxr-xr-x 5 root   root 4096 Oct 19 09:02 ..
> >-rw------- 1 daemon lp      0 Oct  5 14:32 acct
> >-rw------- 1 daemon lp      0 Oct  5 14:32 log
> >-rw------- 1 daemon lp      0 Oct  5 14:32 status
> >-rw------- 1 daemon lp      0 Oct  5 14:32 status.pr
> >root@notlookedfor:/home/hendrik#

> >
> >and it contains no .seq file. Preumably that fle would be created as needed.
> >And presumably the permissions are checked in some way that can exclude root.
> >
> >
>
>     Hi Hendrik.

>
>     I can see one reason for root to be unable to get the
> permission: lpr being owned by another user than root and being
> suid; this is fine at the condidiont that this owner is 'daemon',
> given the owner and permissions of /var/spool/lpd.

>
>     Didier


root@notlookedfor:/home/hendrik# which lpr
/usr/bin/lpr
rroot@notlookedfor:/home/hendrik# ls -l /usr/bin/lpr
-rwsr-sr-x 1 root lp 26536 Nov 20 2014 /usr/bin/lpr
root@notlookedfor:/home/hendrik#

It looks as if it is suid root. Does the second 's' mean to switch
group id as well as uid?

Just as a reminder, let me mention that I installed from scratch, on a
new hard drive, using devuan alpha 2. There should be no legacy junk
left over from a previous Debian installation. Anything wrong with
my system is proesumably there from the beginning.

I did have cups installed temporarily, which I uninstalled when it
couldn't find any printer driver.

Isn't there documentation somewhere that explains how this whole printer
system is supposed to work?

-- hendrik

>
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