I have a snapd-control interface connected to my snap. I execute the following commands from a C# code within the snap:
snap refresh --time
snap get system refresh.timer
They both return empty strings.
Command to set “refresh.timer” works:
snap set system refresh.timer="00:00~24:00/4"
Did I miss to connect some interface?
Logs:
$ snap version
snap 2.46~pre2+git2632.ge1de46e
snapd 2.46~pre2+git2632.ge1de46e
series 16
kernel 5.3.0-1030-raspi2
$ snap list |grep core
core18 20200807 1911 latest/edge canonical* base
$ journalctl
Aug 13 07:25:49 mybox03 audit[17171]: AVC apparmor="DENIED" operation="open" profile="snap.my-snap.my-snap" name="/sys/kernel/security/apparmor/features/" pid=17171 comm="snap" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
Aug 13 07:25:49 mybox03 audit[17178]: AVC apparmor="DENIED" operation="exec" profile="snap.my-snap.my-snap" name="/sbin/apparmor_parser" pid=17178 comm="snap" requested_mask="x" denied_mask="x" fsuid=0 ouid=0
Aug 13 07:25:49 mybox03 kernel: audit: type=1400 audit(1597303549.793:533): apparmor="DENIED" operation="open" profile="snap.my-snap.my-snap" name="/sys/kernel/security/apparmor/features/" pid=17171 comm="snap" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
Aug 13 07:25:49 mybox03 kernel: audit: type=1400 audit(1597303549.793:534): apparmor="DENIED" operation="exec" profile="snap.my-snap.my-snap" name="/sbin/apparmor_parser" pid=17178 comm="snap" requested_mask="x" denied_mask="x" fsuid=0 ouid=0
Aug 13 07:25:49 mybox03 dbus-daemon[1129]: [system] Activating via systemd: service name='org.freedesktop.hostname1' unit='dbus-org.freedesktop.hostname1.service' requested by ':1.35' (uid=0 pid=17172 comm="/usr/bin/hostnamectl " label="snap.my-snap.my-snap (enforce)")
Aug 13 07:25:49 mybox03 systemd[1]: Starting Hostname Service...
Aug 13 07:25:49 mybox03 dbus-daemon[1129]: [system] Successfully activated service 'org.freedesktop.hostname1'
Aug 13 07:25:49 mybox03 systemd[1]: Started Hostname Service.
Aug 13 07:25:49 mybox03 audit[1129]: USER_AVC pid=1129 uid=100 auid=4294967295 ses=4294967295 msg='apparmor="DENIED" operation="dbus_method_call" bus="system" path="/org/freedesktop/systemd1" interface="org.freedesktop.DBus.Properties" member="GetAll" mask="send" name="org.freedesktop.systemd1" pid=17172 label="snap.my-snap.my-snap" peer_pid=1 peer_label="unconfined"
exe="/usr/bin/dbus-daemon" sauid=100 hostname=? addr=? terminal=?'
Aug 13 07:25:49 mybox03 kernel: audit: type=1107 audit(1597303549.957:535): pid=1129 uid=100 auid=4294967295 ses=4294967295 msg='apparmor="DENIED" operation="dbus_method_call" bus="system" path="/org/freedesktop/systemd1" interface="org.freedesktop.DBus.Properties" member="GetAll" mask="send" name="org.freedesktop.systemd1" pid=17172 label="snap.my-snap.my-snap" peer_pid=1 peer_label="unconfined"
exe="/usr/bin/dbus-daemon" sauid=100 hostname=? addr=? terminal=?'
Aug 13 07:25:50 mybox03 dbus-daemon[1129]: [system] Activating via systemd: service name='org.freedesktop.timedate1' unit='dbus-org.freedesktop.timedate1.service' requested by ':1.37' (uid=0 pid=17186 comm="/usr/bin/timedatectl.real " label="snap.my-snap.my-snap (enforce)")
Aug 13 07:25:50 mybox03 systemd[1]: Starting Time & Date Service...
Aug 13 07:25:50 mybox03 systemd-timedated[17187]: /etc/localtime should be a symbolic link to a time zone data file in /usr/share/zoneinfo/.
Aug 13 07:25:50 mybox03 dbus-daemon[1129]: [system] Successfully activated service 'org.freedesktop.timedate1'
Aug 13 07:25:50 mybox03 systemd[1]: Started Time & Date Service.
Aug 13 07:25:50 mybox03 audit[1169]: AVC apparmor="DENIED" operation="ptrace" profile="snap.network-manager.networkmanager" pid=1169 comm="NetworkManager" requested_mask="read" denied_mask="read" peer="snap.my-snap.my-snap"
Aug 13 07:25:50 mybox03 kernel: audit: type=1400 audit(1597303550.453:536): apparmor="DENIED" operation="ptrace" profile="snap.network-manager.networkmanager" pid=1169 comm="NetworkManager" requested_mask="read" denied_mask="read" peer="snap.my-snap.my-snap"
Aug 13 07:25:50 mybox03 audit[1169]: AVC apparmor="DENIED" operation="ptrace" profile="snap.network-manager.networkmanager" pid=1169 comm="NetworkManager" requested_mask="read" denied_mask="read" peer="snap.my-snap.my-snap"
Aug 13 07:25:50 mybox03 kernel: audit: type=1400 audit(1597303550.457:537): apparmor="DENIED" operation="ptrace" profile="snap.network-manager.networkmanager" pid=1169 comm="NetworkManager" requested_mask="read" denied_mask="read" peer="snap.my-snap.my-snap"
Aug 13 07:25:50 mybox03 my-snap.my-snap[1195]: Error: Hotspot - no such connection profile.
Aug 13 07:25:50 mybox03 audit[1169]: AVC apparmor="DENIED" operation="ptrace" profile="snap.network-manager.networkmanager" pid=1169 comm="NetworkManager" requested_mask="read" denied_mask="read" peer="snap.my-snap.my-snap"
Aug 13 07:25:50 mybox03 kernel: audit: type=1400 audit(1597303550.469:538): apparmor="DENIED" operation="ptrace" profile="snap.network-manager.networkmanager" pid=1169 comm="NetworkManager" requested_mask="read" denied_mask="read" peer="snap.my-snap.my-snap"
Aug 13 07:25:50 mybox03 audit[17192]: AVC apparmor="DENIED" operation="open" profile="snap.my-snap.my-snap" name="/sys/kernel/security/apparmor/features/" pid=17192 comm="snap" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
Aug 13 07:25:50 mybox03 kernel: audit: type=1400 audit(1597303550.577:539): apparmor="DENIED" operation="open" profile="snap.my-snap.my-snap" name="/sys/kernel/security/apparmor/features/" pid=17192 comm="snap" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
Aug 13 07:25:50 mybox03 audit[17198]: AVC apparmor="DENIED" operation="exec" profile="snap.my-snap.my-snap" name="/sbin/apparmor_parser" pid=17198 comm="snap" requested_mask="x" denied_mask="x" fsuid=0 ouid=0
Aug 13 07:25:50 mybox03 kernel: audit: type=1400 audit(1597303550.581:540): apparmor="DENIED" operation="exec" profile="snap.my-snap.my-snap" name="/sbin/apparmor_parser" pid=17198 comm="snap" requested_mask="x" denied_mask="x" fsuid=0 ouid=0
Aug 13 07:25:50 mybox03 my-snap.my-snap[1195]: error: unknown flag `timer'
Aug 13 07:25:50 mybox03 my-snap.my-snap[1195]: WARNING: There are 2 new warnings. See 'snap warnings'.
Aug 13 07:25:50 mybox03 audit[17207]: AVC apparmor="DENIED" operation="open" profile="snap.my-snap.my-snap" name="/sys/kernel/security/apparmor/features/" pid=17207 comm="snap" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
Aug 13 07:25:50 mybox03 audit[17213]: AVC apparmor="DENIED" operation="exec" profile="snap.my-snap.my-snap" name="/sbin/apparmor_parser" pid=17213 comm="snap" requested_mask="x" denied_mask="x" fsuid=0 ouid=0
Aug 13 07:25:50 mybox03 kernel: audit: type=1400 audit(1597303550.729:541): apparmor="DENIED" operation="open" profile="snap.my-snap.my-snap" name="/sys/kernel/security/apparmor/features/" pid=17207 comm="snap" requested_mask="r" denied_mask="r" fsuid=0 ouid=0
Aug 13 07:25:50 mybox03 kernel: audit: type=1400 audit(1597303550.729:542): apparmor="DENIED" operation="exec" profile="snap.my-snap.my-snap" name="/sbin/apparmor_parser" pid=17213 comm="snap" requested_mask="x" denied_mask="x" fsuid=0 ouid=0
Aug 13 07:25:50 mybox03 my-snap.my-snap[1195]: error: unknown flag `timer'