Bug#953176: cups-daemon: cupsd with socket-activation removes /run/cups/cups.sock on exit

[Johan Hattne <johan@hattne.se>]

Package: cups-daemon
Version: 2.2.10-6+deb10u2
Severity: important

Dear Maintainer,

systemd creates /run/cups/cups.sock on boot and as soon as anything 
connects to it (by e.g. lpstat), cupsd -l starts as expected.  There are 
no shared printers on the system and the web interface is not running, 
so cupsd will eventually exit.  When it does, I find it will unlink 
/run/cups/cups.sock (seen by strace on the running cupsd process), which 
causes subsequent invocations of lpstat to fail with "Bad file descriptor".

cupsd did not remove the socket in Stretch, but in Buster it does.


-- System Information:
Debian Release: 10.3
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'oldstable-updates'), 
(500, 'stable'), (500, 'oldstable')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-8-amd64 (SMP w/16 CPU cores)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, 
TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), 
LANGUAGE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages cups-daemon depends on:
ii  adduser           3.118
ii  bc                1.07.1-2+b1
ii  libavahi-client3  0.7-4+b1
ii  libavahi-common3  0.7-4+b1
ii  libc6             2.28-10
ii  libcups2          2.2.10-6+deb10u2
ii  libdbus-1-3       1.12.16-1
ii  libgssapi-krb5-2  1.17-3
ii  libpam0g          1.3.1-5
ii  libpaper1         1.1.28
ii  libsystemd0       241-7~deb10u3
ii  lsb-base          10.2019051400
ii  procps            2:3.3.15-2
ii  ssl-cert          1.0.39

Versions of packages cups-daemon recommends:
ii  avahi-daemon  0.7-4+b1
ii  colord        1.4.3-4
pn  cups-browsed  <none>

Versions of packages cups-daemon suggests:
ii  cups                                       2.2.10-6+deb10u2
ii  cups-bsd                                   2.2.10-6+deb10u2
ii  cups-client                                2.2.10-6+deb10u2
ii  cups-common                                2.2.10-6+deb10u2
ii  cups-filters [foomatic-filters]            1.21.6-5
pn  cups-pdf                                   <none>
ii  cups-ppdc                                  2.2.10-6+deb10u2
ii  cups-server-common                         2.2.10-6+deb10u2
pn  foomatic-db-compressed-ppds | foomatic-db  <none>
ii  ghostscript                                9.27~dfsg-2+deb10u3
pn  hplip                                      <none>
ii  poppler-utils                              0.71.0-5
ii  printer-driver-gutenprint                  5.3.1-7
ii  printer-driver-hpcups                      3.18.12+dfsg0-2
pn  smbclient                                  <none>
ii  udev                                       241-7~deb10u3

-- no debconf information