With CUPS v2.3b5, the configuration directive `SetEnv`
moved from `cupsd.conf` to `cups-files.conf`. See also
d47f6aec43 .
We have to follow up as `SetEnv` is now ignored in `cupsd.conf`.
Without this, executables called by cups
can't find other executables they depend on,
like `gs` or `perl`.
Previously we indirectly suggested that the user use
services.printing.extraConf to set this, but this doesn't work with the
default merge ordering. Fix this by making it an independent option.
Fixes #39611.
Use systemd to create the directory for UNIX socket. Also use localhost instead
of 127.0.0.1 as is done in default cupsd.conf so that IPv6 is enabled when
available.
Additional CUPS drivers can be added via "services.printing.drivers" but
Gutenprint was an exception. It was possible to add a Gutenprint
derivation to that list and it would work at first but unlike the other
drivers Gutenprint requires a script to be run after each update or any
attempt to print something would simply fail and an error would show up
in the jobs queue (http://localhost:631/jobs/):
"The PPD version (5.2.11) is not compatible with Gutenprint 5.2.13.
Please run
`/nix/store/7762kpyhfkcgmr3q81v1bbyy0bjhym80-gutenprint-5.2.13/sbin/cups-genppdupdate'
as administrator."
This is due to state in "/var/lib/cups/ppd" and one would need to run
"/nix/store/.../bin/cups-genppdupdate -p /var/lib/cups/ppd" manually.
The alternative was to enable the following option:
"services.printing.gutenprint" but this had two disadvantages:
1) It is an exception that one could be unaware of or that could
potentially cause some confusion.
2) One couldn't use a customized Gutenprint derivation in
"services.printing.drivers" but would instead have to overwrite
"pkgs.gutenprint".
This new approach simply detects a Gutenprint derivation in
"services.printing.gutenprint" by checking if the meta set of a
derivation contains "isGutenprint = true". Therefore no special
exception for Gutenprint would be required and it could easily be
applied to other drivers if they would require such a script to be run.
printer driver and wrapper are often not written with security in mind.
While reviewing https://github.com/NixOS/nixpkgs/pull/25654 I found
a symlink-race vulnerability within the wrapper code, when writing
unique files in /tmp.
I expect this script to be reused in other models as well
as similar vulnerabilities in the code of other vendors. Therefore
I propose to make /tmp of cups.service private so that only processes
with the same privileges are able to access these files.
even if cups rewrites its config file due to config changes made through
its web-based management UI, we need to keep the PATH pointing to
currently-live nix store directories. fixes #20806.
Need to pass `cups.out` to `systemd.packages`, lest we end up with an invalid
generated unit containing only directives set in the service module.
This patch gives us a valid cups.service unit but, vexingly, does not fix the
test failure at NixOS/nixpkgs#14748
And set the default value to "Address @LOCAL". This change is needed to
find printers at my workplace (with "lpinfo -v" or the
"system-config-printer" GUI). Ubuntu 14.04 also has this as default.
snmp.conf does not seem to be needed in restartTriggers, because it is
not the cups daemon itself that reads it, but some helper programs that
it spawns on demand.
This gets rid of
systemd[1]: Cannot add dependency job for unit avahi-daemon.service, ignoring: Unit avahi-daemon.service failed to load: No such file or directory.
