Bug 21164

Assigning to the registered samba maintainer

Summary: Problem with SMB backend for CUPS => Problem with SMB backend for CUPS, caused by /usr/lib/cups/backend/smb danging link
CC: (none) => marja11
Assignee: bugsquad => bgmilne
Source RPM: (none) => samba-4.6.5-1.mga6

Bug confirmed here :
https://www.mageialinux-online.org/forum/topic-24043-1+probleme-mageia6-pour-configurer-une-imprimante-avec-le-protocol-smb.php#m231071

and workaround also confirmed. Thanks Nicolas.

We need now a packager to correct the problem.

CC: (none) => yves.brungard_mageia

Please, add this information in Mageia 7 Errata.

Still valid.

CC: (none) => lrampazzo

The problem was introduced by the switch from samba-3.x to samba-4.x (where a different distribution's samba package was imported without considering all the possible impact, in http://svnweb.mageia.org/packages/cauldron/samba/current/SPECS/samba.spec?r1=852307&r2=854335 )

Previously, the samba (samba-client) package managed the /usr/lib/cups/backend/smb symlink as a slave of the smbclient alternative ( http://svnweb.mageia.org/packages/cauldron/samba/current/SPECS/samba.spec?revision=852307&view=markup&pathrev=852307#l1728 ), and systems that had the previous version still have the alternative installed:

[root@media ~]# update-alternatives --display smbclient
smbclient - status is auto.
 link currently points to /usr/bin/smbclient3
/usr/bin/smbclient3 - priority 10
 slave cups_smb: /usr/lib/cups/backend/smb3
 slave findsmb.1: /usr/share/man/man1/findsmb3.1.xz
 slave findsmb: /usr/bin/findsmb3
 slave smbspool.8: /usr/share/man/man8/smbspool3.8.xz
 slave smbget.1: /usr/share/man/man1/smbget3.1.xz
 slave smbtar.1: /usr/share/man/man1/smbtar3.1.xz
 slave nmblookup: /usr/bin/nmblookup3
 slave smbgetrc.5: /usr/share/man/man5/smbgetrc3.5.xz
 slave smbget: /usr/bin/smbget3
 slave smbtar: /usr/bin/smbtar3
 slave nmblookup.1: /usr/share/man/man1/nmblookup3.1.xz
 slave eventlogadm: /usr/bin/eventlogadm3
 slave smbclient.1: /usr/share/man/man1/smbclient3.1.xz
 slave smbprint: /usr/bin/smbprint3
 slave smbspool: /usr/bin/smbspool3
Current `best' version is /usr/bin/smbclient3.
[root@media ~]#


There are now ( http://svnweb.mageia.org/packages/cauldron/samba/current/SPECS/samba.spec?revision=1436819&view=markup#l892 ) update-alternatives configurations that maintain the symlink /usr/libexec/samba/cups_backend_smb:

[root@buchan-desktop ~]# update-alternatives --display cups_backend_smb
cups_backend_smb - status is auto.
 link currently points to /usr/bin/smbspool
/usr/bin/smbspool - priority 10
Current `best' version is /usr/bin/smbspool.
[root@buchan-desktop ~]# cat /var/lib/alternatives/cups_backend_smb 
auto
/usr/libexec/samba/cups_backend_smb

/usr/bin/smbspool
10
[root@buchan-desktop ~]#


Another alternative is provided in the samba-krb5-printing sub-package, for a kerberos-wrapped backend.

So, the real question is, which package should own the /usr/lib/cups/backend/smb symlink?

If the samba package should own it, I would maybe rather change this update-alternatives config to add a "slave", but e.g. in Fedora, the cups package owns the /usr/lib/cups/backend symlink:

https://src.fedoraproject.org/rpms/cups/blob/master/f/cups.spec#_591

I propose:
* samba package to add removal of the old smbclient alternatives
* cups package adds the symlink via trigger following Fedora's convention pointing to the existing symlink /usr/libexec/samba/cups_backend_smb which is already present in the samba-client package.

(I wouldn't mind resolving this soon so I could potentially include this for the pending samba update for Mageia 7).


(trying to re-assign to cups maintainer tv@)

Source RPM: samba-4.6.5-1.mga6 => cups-2.2.11-2.mga7.src.rpm
CC: (none) => bgmilne
Assignee: bgmilne => bugsquad

To clean up what is in scope for the samba package, it looks like calling:

update-alternatives --remove smbclient /usr/bin/smbclient3 || :


should be enough:

[root@media ~]# ls -l /usr/lib/cups/backend/smb 
lrwxrwxrwx 1 root root 26 Jun 23  2013 /usr/lib/cups/backend/smb -> /etc/alternatives/cups_smb
[root@media ~]# ls -l /etc/alternatives/cups_smb
lrwxrwxrwx 1 root root 26 Jul 22  2017 /etc/alternatives/cups_smb -> /usr/lib/cups/backend/smb3
[root@media ~]# update-alternatives --remove smbclient /usr/bin/smbclient3
[root@media ~]# ls -l /etc/alternatives/cups_smb
ls: cannot access '/etc/alternatives/cups_smb': No such file or directory
[root@media ~]# ls -l /usr/lib/cups/backend/smb 
ls: cannot access '/usr/lib/cups/backend/smb': No such file or directory
[root@media ~]# update-alternatives --remove smbclient /usr/bin/smbclient3
[root@media ~]# echo $?
2
[root@media ~]#

But, I need to test some more.

Putting the correct symlink in /usr/lib/cups/backend will need to be done by cups.

Since there wasn't any traction, and it makes just as much sense to add the symlink to samba-client, I have committed a fix in http://svnweb.mageia.org/packages?view=revision&revision=1439385 (cauldron) and http://svnweb.mageia.org/packages?view=revision&revision=1439417 for 7, and I have submitted this to core/updates_testing (samba-4.10.8-2.mga7)

Affected users could help by testing this package on affected machines currently running Mageia 7.

Testing procedure:
1)Before upgrading, run the following commands:
ls -l $(readlink -f /usr/lib/cups/backend/smb )
ls -l $(readlink -f /etc/alternatives/smb*)
/usr/sbin/update-alternatives --list|grep smb
/usr/sbin/update-alternatives --display smbclient
cat /var/lib/alternatives/smbclient

The first command should return:
ls: cannot access '/etc/alternatives/cups_smb': No such file or directory

The 2 command should show a lot of broken symlinks

The other 3 commands provide more information in case the update doesn't do the right thing.


2)Upgrade at least samba-client from updates_testing by running the following commands as root:
urpmi.update "Core Updates Testing"
urpmi --media "Core Updates Testing" samba-client

3)Run the commands from (1) again

This time, the first command should return the listing for /usr/bin/smbspool, e.g.:
-rwxr-xr-x 1 root root 27664 Sep 10 16:10 /usr/bin/smbspool*

The 2nd command should return:
ls: cannot access '/etc/alternatives/smb*': No such file or directory

Ideally, the last 3 commands should return nothing, but it looks like the /var/lib/alternatives/smbclient gets left behind. Since this is mainly cosmetic, I will update cauldron to clean this up, and on upgrading to Mageia 8 (or, if we need to do another update for 7, on applying that update) this remnant should also be removed.

It would be useful to have the all of the output from the 3 sets of commands from anyone who tests this.

Source RPM: cups-2.2.11-2.mga7.src.rpm => samba-4.6.5-1.mga6
Status: NEW => ASSIGNED
Assignee: thierry.vignaud => bugsquad

Created attachment 11274 [details]
Results for commands proposed @ comment #6

This generates an error while updating cups (see bug#25518).

/usr/lib/cups/backend/smb -> /usr/libexec/samba/cups_backend_smb

(In reply to Buchan Milne from comment #4)
> The problem was introduced by the switch from samba-3.x to samba-4.x (where
> a different distribution's samba package was imported without considering
> all the possible impact, in
(...)
> Previously, the samba (samba-client) package managed the
> /usr/lib/cups/backend/smb symlink as a slave of the smbclient alternative (
(...)
> If the samba package should own it, I would maybe rather change this
> update-alternatives config to add a "slave", but e.g. in Fedora, the cups
> package owns the /usr/lib/cups/backend symlink:

(In reply to Buchan Milne from comment #5)
> Putting the correct symlink in /usr/lib/cups/backend will need to be done by
> cups.

it's debatable since /usr/lib/cups/backend/smb is a symlink to /usr/libexec/samba/cups_backend_smb, owned by samba, but I'm OK to add the triggersin into cups

CC: (none) => thierry.vignaud

Currently
Samba is samba-4.12.6-1.mga8 > samba-4.6.5-1.mga6

Cups is cups-2.3.3-6.mga8.

Does this still apply in Cauldron Mageia 8 Beta 1?
Assigning meanwhile to Base System Team.

CC: (none) => ouaurelien
Assignee: bugsquad => basesystem