[Samba] Fwd: "Make_passthrough: pid XXXX, dup2(6, 0) failed" with LPRNG 3.8.C and Samba 4.3.8 on FreeBSD

[Benedikt Hochstrasser]

(FreeBSD 10.3-RELEASE-p4 i386, Lprng 3.8.C and Samba 4.3.8 installed via
pkg())

I have set up a PDF converter queue that converts PS input to PDF and puts
it on its website. Recently I had samba join the AD domain here, and ever
since my pdf converter fails.

Upon much trial, error and debugging I found out that when I start the
Lprng service BEFORE the Samba service, everything is working. However, the
default startup sequence is Samba first, then Lprng (due to dependencies).

More debugging revealed that the problem is the input filter spawning fails
(ie even a dummy filter that only touches "/tmp/hello" is not executed).

In the Log, I get entries like

2016-06-25-12:39:16.710 wagi-util [4827] (Server) pdf: Trim_status_file: '
status.pr' max 10, min 0, size 6197
2016-06-25-12:39:16.710 wagi-util [4827] (Server) pdf: Wait_for_subserver:
pid_to_wait_for -1, flags 1
*Make_passthrough: pid 4829, dup2(6,0) failed*2016-06-25-12:39:16.712
wagi-util [4828] (Worker - Print) pdf: Wait_for_pid: returning 'JFAIL',
exit status 'exit status 32 (JFAIL)'
2016-06-25-12:39:16.712 wagi-util [4828] (Worker - Print) pdf: setstatus:
msg 'IF filter 'pdflpd' filter exit status 'JFAIL''
2016-06-25-12:39:16.712 wagi-util [4828] (Worker - Print) pdf: setstatus:
msg 'printing finished'

The spurious "Make_passthrough" statement looks as if it weren't written by
the normal logging routine but rather was spit out by some other routine.

I have a hunch that samba somehow sits on a file or a process that becomes
unavailable for Lprng, UNLESS Lprng is started before samba.

I disabled printing in samba, gave it a completely unrelated printcap file,
disabled spoolss etc, all to no avail.

Of course, setting up a vanilla FreeBSD in Virtualbox and just installing
Lprng and Samba worked fine in either start sequence, but then I haven't
joined it to a domain nor am I using a modified nsswitch.conf and other
settings that are used in a domain context.

I now have the workaround of stopping both services and starting them in
the correct sequence, but it still bugs me.

Any idea where to look next?

/etc/printcap:
.common:
:sd=/var/spool/lpd/%P
:lf=log
:max_log_file_size=256
:done_status=0
:sh:mx=0:mc=0
pdf:tc=.common:lp=/dev/null:filter=/usr/local/libexec/filters/pdflpd:

/usr/local/etc/smb4.conf
[global]
workgroup = MYDOMAIN
netbios name = MYNAME
security = ads
realm = MYDOMAIN.MYCOMPANY.COM
encrypt passwords = yes
password server = 10.65.10.220
wins server = 10.65.10.220
client ldap sasl wrapping = plain
idmap config * : backend = tdb
idmap config * : range = 2000-9999
idmap config DPRDOM : backend = rid
idmap config DORDOM : range = 10000-29999
winbind enum users = yes
winbind enum groups = yes
winbind nested groups = yes
dos charset = CP850
unix charset = UTF8
restrict anonymous = 2
server string = "Utility Server"
load printers = No
printing = bsd
printcap name = /usr/local/etc/samba-printcap
disable spoolss = Yes
local master = no
smb ports = 445
map to guest = Bad User
read raw = Yes
write raw = Yes
max xmit = 65535
socket options = TCP_NODELAY IPTOS_LOWDELAY
use sendfile = true
vfs objects = acl_xattr
map acl inherit = Yes
store dos attributes = Yes
oplocks = Yes


Stumped in Zurich