When I install Chromium on the LXD container by using Snap, the installation finishes without error.
ubuntu@lxdcontainer:~$ sudo snap install chromium
chromium 86.0.4240.111 from Canonical✓ installed
However, when I then try to launch Chromium, I get the below error:
ubuntu@lxdcontainer:~$ chromium
cannot locate base snap core18: Permission denied
What can I do to do to troubleshoot this further?
Note: I get the same error with the flameshot snap. I, therefore, suspect this error is a generic Snap issue observed with an Ubuntu 20.10 LXD container.
I am observing bizarre behaviour now, which I cannot plausibly explain.
When I created this post initially, I created a container and then another one when the first troubleshooting suggestions arrived.
Today, I see that those two “old” containers do not inhabit this error cannot locate base snap core18: Permission denied anymore but instead successfully launch the Chromium browser.
To investigate this further, I have now created a new, a third, container named ‘lxdcontainer3’ and followed the same steps as previously outlined. There I get the cannot locate base snap core18: Permission denied error again.
I then stopped the LXD service on the laptop (LXD host) with sudo snap stop lxd and then started it again with sudo snap start lxd. After this, I connected to the container ‘lxdcontainer3’ again, and I still got the cannot locate base snap core18: Permission denied error when trying to launch the Chromium browser.
Since my laptop on which those containers run gets shut down when not used I suspected that a shut down might affect the behaviour observed. In the light of this, I shut down and booted my laptop and tested this with the ‘lxdcontainer3’ container again but the problem persisted.
As of the behaviour observed so far, I have the hunch that ‘lxdcontainer3’ may work tomorrow…
My laptop was shutdown over the weekend and I now tried to launch Chromium that is installed in ‘lxdcontainer3’ and it worked.
Behaviour summary as currently observed:
When restarting the entire Ubuntu LXD host (laptop with snap LXD installed), the problem persists with error cannot locate base snap core18: Permission denied.
When shutting down the Ubuntu LXD host and leave it until the next day (another calendar date), launching Chromium in the LXD container works.
I didn’t have luck reproducing this (I tried with a few 18.04 lxd containers; lxd snap 4.7 rev 18137, running on groovy as a host, restarted the host a couple of times); I didn’t have luck setting them for GUI apps following that tutorial though, but I think this may not be relevant for the problem; FWTW I had chromium and firefox snaps inside containers, they would run from snaps and were just failing accessing X.
One possible explanation (but it may be a long shot) is that something fails during an automatic snap refresh, and current symlink for core18 is lost; could you please:
see (now) if there are any errors reported by snap changes (and if there is an error, run snap change <id> where id is the id of the failed change and attach the output)
if the problems happens again, check snap changes again and also check if /snap/core18/current is a valid symlink?
As you mentioned that you tried with Ubuntu 18.04 LXD containers, I have tested this with Ubuntu 18.04 LXD containers now and can confirm that Chromium works with Ubuntu 18.04 LXD containers.
When testing with 18.04 LXD I noticed that snap list, on a vanilla 18.04 LXD container, shows no Snaps installed
ubuntu@lxdcontainer5:~$ snap list
No snaps are installed yet. Try 'snap install hello-world'.
Whereas snap list, on a vanilla 20.10 LXD container, shows;
ubuntu@lxdcontainer6:~$ sudo snap list
Name Version Rev Tracking Publisher Notes
core18 20200929 1932 latest/stable canonical✓ base
lxd 4.7 18137 latest/stable/… canonical✓ -
snapd 2.47.1 9721 latest/stable canonical✓ snap
Based on this, I figured out a workaround to make Chromium work immediately after it was installed, avoiding the Cannot locate base snap core18: Permission denied error.
The workaround is to basically uninstall the LXD and the core18 snaps and then install Chromium.
Below are is the sequence of commands to work around this error.
$ export LXD_CONTAINER_NAME="lxdcontainer6"
$ lxc launch ubuntu:20.10 --profile default $LXD_CONTAINER_NAME
Creating lxdcontainer6
Starting lxdcontainer6
$ lxc exec $LXD_CONTAINER_NAME -- sudo --user ubuntu --login
To run a command as administrator (user "root"), use "sudo <command>".
See "man sudo_root" for details.
ubuntu@lxdcontainer6:~$ sudo snap list
Name Version Rev Tracking Publisher Notes
core18 20200929 1932 latest/stable canonical✓ base
lxd 4.7 18137 latest/stable/… canonical✓ -
snapd 2.47.1 9721 latest/stable canonical✓ snapd
ubuntu@lxdcontainer6:~$ sudo snap remove lxd
lxd removed
ubuntu@lxdcontainer6:~$ sudo snap remove core18
core18 removed
ubuntu@lxdcontainer6:~$ sudo snap list
Name Version Rev Tracking Publisher Notes
snapd 2.47.1 9721 latest/stable canonical✓ snapd
ubuntu@lxdcontainer6:~$ sudo snap changes
ID Status Spawn Ready Summary
1 Done yesterday at 11:33 UTC today at 00:10 UTC Initialize system state
2 Done today at 00:10 UTC today at 00:10 UTC Initialize device
3 Done today at 00:10 UTC today at 00:10 UTC Remove "lxd" snap
4 Done today at 00:10 UTC today at 00:10 UTC Remove "core18" snap
ubuntu@lxdcontainer6:~$ sudo snap install chromium
chromium 86.0.4240.111 from Canonical✓ installed
ubuntu@lxdcontainer6:~$ sudo snap changes
ID Status Spawn Ready Summary
1 Done yesterday at 11:33 UTC today at 00:10 UTC Initialize system state
2 Done today at 00:10 UTC today at 00:10 UTC Initialize device
3 Done today at 00:10 UTC today at 00:10 UTC Remove "lxd" snap
4 Done today at 00:10 UTC today at 00:10 UTC Remove "core18" snap
5 Done today at 00:10 UTC today at 00:14 UTC Install "chromium" snap
ubuntu@lxdcontainer6:~$ sudo snap list
Name Version Rev Tracking Publisher Notes
chromium 86.0.4240.111 1373 latest/stable canonical✓ -
core18 20200929 1932 latest/stable canonical✓ base
gtk-common-themes 0.1-36-gc75f853 1506 latest/stable canonical✓ -
snapd 2.47.1 9721 latest/stable canonical✓ snapd
ubuntu@lxdcontainer6:~$ ls -lah /snap/core18/1932
total 0
lrwxrwxrwx 1 root root 15 Sep 29 10:44 .disk -> /writable/.disk
drwxr-xr-x 2 root root 0 Sep 29 10:45 bin
drwxr-xr-x 6 root root 0 Sep 29 10:45 boot
drwxr-xr-x 2 root root 0 Sep 29 10:45 dev
drwxr-xr-x 42 root root 0 Sep 29 10:45 etc
drwxr-xr-x 2 root root 0 Apr 24 2018 home
drwxr-xr-x 14 root root 0 Sep 29 10:45 lib
drwxr-xr-x 2 root root 0 Sep 29 10:45 lib64
drwxr-xr-x 2 root root 0 Aug 6 22:33 media
drwxr-xr-x 2 root root 0 Sep 29 10:45 meta
drwxr-xr-x 2 root root 0 Aug 6 22:33 mnt
drwxr-xr-x 2 root root 0 Aug 6 22:33 opt
drwxr-xr-x 2 root root 0 Apr 24 2018 proc
drwx------ 2 root root 0 Sep 29 10:45 root
drwxr-xr-x 2 root root 0 Sep 29 10:44 run
drwxr-xr-x 2 root root 0 Sep 29 10:45 sbin
drwxr-xr-x 2 root root 0 Sep 29 10:45 snap
drwxr-xr-x 2 root root 0 Aug 6 22:33 srv
-rw-r--r-- 1 root root 53 Sep 29 10:45 stdout
drwxr-xr-x 2 root root 0 Apr 24 2018 sys
drwxrwxrwt 2 root root 0 Sep 29 10:45 tmp
drwxr-xr-x 11 root root 0 Sep 29 10:45 usr
drwxr-xr-x 12 root root 0 Sep 29 10:45 var
drwxr-xr-x 2 root root 0 Sep 29 10:44 writable
ubuntu@lxdcontainer6:~$ chromium
mkdir: cannot create directory ‘/run/user/1000’: Permission denied
[1457:1457:1104/001543.990873:ERROR:browser_main_loop.cc(1426)] Unable to open X display.
Since this problem reported with this post is not related to the X display forwarding, I am using the default LXD profile here and therefore the Unable to open X display error shown above is expected and not of relevance.
In answer to your question, to verify that /snap/core18/current is a valid symlink, I have observed the following:
The symlink shows correctly on the LXD host and the LXD containers:
ubuntu@lxdcontainer6:~$ ls -lah /snap/core18/current
lrwxrwxrwx 1 root root 4 Nov 4 00:11 /snap/core18/current -> 1932
However, the target directory 1932 shows permission denied when run from within the container:
ubuntu@lxdcontainer8:~$ ls -lah /snap/core18/1932
ls: cannot access '/snap/core18/1932': Permission denied
When doing an ls for the /snap/core18 directory from within the LXD container, I get:
ubuntu@lxdcontainer8:~$ ls -lah /snap/core18/
ls: cannot access '/snap/core18/1932': Permission denied
total 2.5K
drwxr-xr-x 3 root root 4 Nov 3 11:33 .
drwxr-xr-x 8 root root 9 Nov 4 00:44 ..
d????????? ? ? ? ? ? 1932
lrwxrwxrwx 1 root root 4 Nov 3 11:33 current -> 1932
Given the workaround I posted, I now got the impression this problem is not a problem with the Chromium snap but possibly a problem as to how core18 is installed on the LXD base image for Ubuntu 20:10.
What do you think?
For brevity, here is the sequence of commands to reproduce the error.
$ export LXD_CONTAINER_NAME="lxdcontainer8"
$ lxc launch ubuntu:20.10 --profile default $LXD_CONTAINER_NAME
Creating lxdcontainer8
Starting lxdcontainer8
$ lxc exec $LXD_CONTAINER_NAME -- sudo --user ubuntu --login
ubuntu@lxdcontainer8:~$ sudo snap list
Name Version Rev Tracking Publisher Notes
core18 20200929 1932 latest/stable canonical✓ base
lxd 4.7 18137 latest/stable/… canonical✓ -
snapd 2.47.1 9721 latest/stable canonical✓ snapd
ubuntu@lxdcontainer8:~$ ls -lah /snap/core18/
ls: cannot access '/snap/core18/1932': Permission denied
total 2.5K
drwxr-xr-x 3 root root 4 Nov 3 11:33 .
drwxr-xr-x 6 root root 7 Nov 3 11:33 ..
d????????? ? ? ? ? ? 1932
lrwxrwxrwx 1 root root 4 Nov 3 11:33 current -> 1932
ubuntu@lxdcontainer8:~$ sudo snap changes
ID Status Spawn Ready Summary
1 Done yesterday at 11:33 UTC today at 00:39 UTC Initialize system state
2 Done today at 00:39 UTC today at 00:40 UTC Initialize device
ubuntu@lxdcontainer8:~$ sudo snap install chromium
chromium 86.0.4240.111 from Canonical✓ installed
ubuntu@lxdcontainer8:~$ sudo snap list
Name Version Rev Tracking Publisher Notes
chromium 86.0.4240.111 1373 latest/stable canonical✓ -
core18 20200929 1932 latest/stable canonical✓ base
gtk-common-themes 0.1-36-gc75f853 1506 latest/stable canonical✓ -
lxd 4.7 18137 latest/stable/… canonical✓ -
snapd 2.47.1 9721 latest/stable canonical✓ snapd
ubuntu@lxdcontainer8:~$ sudo snap changes
ID Status Spawn Ready Summary
1 Done yesterday at 11:33 UTC today at 00:39 UTC Initialize system state
2 Done today at 00:39 UTC today at 00:40 UTC Initialize device
3 Done today at 00:42 UTC today at 00:44 UTC Install "chromium" snap
ubuntu@lxdcontainer8:~$ chromium
cannot locate base snap core18: Permission denied
ubuntu@lxdcontainer8:~$ ls -lah /snap/core18/
ls: cannot access '/snap/core18/1932': Permission denied
total 2.5K
drwxr-xr-x 3 root root 4 Nov 3 11:33 .
drwxr-xr-x 8 root root 9 Nov 4 00:44 ..
d????????? ? ? ? ? ? 1932
lrwxrwxrwx 1 root root 4 Nov 3 11:33 current -> 1932
ubuntu@lxdcontainer8:~$ sudo snap change 1
Status Spawn Ready Summary
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Ensure prerequisites for "snapd" are available
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Prepare snap "/var/lib/snapd/seed/snaps/snapd_9721.snap" (9721)
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Mount snap "snapd" (9721)
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Copy snap "snapd" data
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Setup snap "snapd" (9721) security profiles
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Make snap "snapd" (9721) available to the system
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Automatically connect eligible plugs and slots of snap "snapd"
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Set automatic aliases for snap "snapd"
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Setup snap "snapd" aliases
Done yesterday at 11:33 UTC today at 00:39 UTC Run install hook of "snapd" snap if present
Done yesterday at 11:33 UTC today at 00:39 UTC Start snap "snapd" (9721) services
Done yesterday at 11:33 UTC today at 00:39 UTC Run configure hook of "core" snap if present
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Ensure prerequisites for "core18" are available
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Prepare snap "/var/lib/snapd/seed/snaps/core18_1932.snap" (1932)
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Mount snap "core18" (1932)
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Copy snap "core18" data
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Setup snap "core18" (1932) security profiles
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Make snap "core18" (1932) available to the system
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Automatically connect eligible plugs and slots of snap "core18"
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Set automatic aliases for snap "core18"
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Setup snap "core18" aliases
Done yesterday at 11:33 UTC today at 00:39 UTC Run install hook of "core18" snap if present
Done yesterday at 11:33 UTC today at 00:39 UTC Start snap "core18" (1932) services
Done yesterday at 11:33 UTC today at 00:39 UTC Run health check of "core18" snap
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Ensure prerequisites for "lxd" are available
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Prepare snap "/var/lib/snapd/seed/snaps/lxd_18137.snap" (18137)
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Mount snap "lxd" (18137)
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Copy snap "lxd" data
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Setup snap "lxd" (18137) security profiles
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Make snap "lxd" (18137) available to the system
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Automatically connect eligible plugs and slots of snap "lxd"
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Set automatic aliases for snap "lxd"
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Setup snap "lxd" aliases
Done yesterday at 11:33 UTC today at 00:39 UTC Run install hook of "lxd" snap if present
Done yesterday at 11:33 UTC today at 00:39 UTC Start snap "lxd" (18137) services
Done yesterday at 11:33 UTC today at 00:39 UTC Run configure hook of "lxd" snap if present
Done yesterday at 11:33 UTC today at 00:39 UTC Run health check of "lxd" snap
Done yesterday at 11:33 UTC today at 00:39 UTC Mark system pre-seeded
Done yesterday at 11:33 UTC today at 00:39 UTC Mark system seeded
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Connect lxd:lxd-support to snapd:lxd-support
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Connect lxd:network to snapd:network
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Connect lxd:network-bind to snapd:network-bind
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Connect lxd:system-observe to snapd:system-observe
Done yesterday at 11:33 UTC yesterday at 11:33 UTC Setup snap "lxd" (18137) security profiles for auto-connections
ubuntu@lxdcontainer8:~$ sudo snap change 2
Status Spawn Ready Summary
Done today at 00:39 UTC today at 00:39 UTC Generate device key
Done today at 00:39 UTC today at 00:40 UTC Request device serial
ubuntu@lxdcontainer8:~$ sudo snap change 3
Status Spawn Ready Summary
Done today at 00:42 UTC today at 00:42 UTC Ensure prerequisites for "chromium" are available
Done today at 00:42 UTC today at 00:44 UTC Download snap "chromium" (1373) from channel "stable"
Done today at 00:42 UTC today at 00:44 UTC Fetch and check assertions for snap "chromium" (1373)
Done today at 00:42 UTC today at 00:44 UTC Mount snap "chromium" (1373)
Done today at 00:42 UTC today at 00:44 UTC Copy snap "chromium" data
Done today at 00:42 UTC today at 00:44 UTC Setup snap "chromium" (1373) security profiles
Done today at 00:42 UTC today at 00:44 UTC Make snap "chromium" (1373) available to the system
Done today at 00:42 UTC today at 00:44 UTC Automatically connect eligible plugs and slots of snap "chromium"
Done today at 00:42 UTC today at 00:44 UTC Set automatic aliases for snap "chromium"
Done today at 00:42 UTC today at 00:44 UTC Setup snap "chromium" aliases
Done today at 00:42 UTC today at 00:44 UTC Run install hook of "chromium" snap if present
Done today at 00:42 UTC today at 00:44 UTC Start snap "chromium" (1373) services
Done today at 00:42 UTC today at 00:44 UTC Run configure hook of "chromium" snap if present
Done today at 00:42 UTC today at 00:44 UTC Run health check of "chromium" snap
Done today at 00:42 UTC today at 00:42 UTC Ensure prerequisites for "gtk-common-themes" are available
Done today at 00:42 UTC today at 00:43 UTC Download snap "gtk-common-themes" (1506) from channel "stable"
Done today at 00:42 UTC today at 00:43 UTC Fetch and check assertions for snap "gtk-common-themes" (1506)
Done today at 00:42 UTC today at 00:43 UTC Mount snap "gtk-common-themes" (1506)
Done today at 00:42 UTC today at 00:43 UTC Copy snap "gtk-common-themes" data
Done today at 00:42 UTC today at 00:43 UTC Setup snap "gtk-common-themes" (1506) security profiles
Done today at 00:42 UTC today at 00:43 UTC Make snap "gtk-common-themes" (1506) available to the system
Done today at 00:42 UTC today at 00:43 UTC Automatically connect eligible plugs and slots of snap "gtk-common-themes"
Done today at 00:42 UTC today at 00:43 UTC Set automatic aliases for snap "gtk-common-themes"
Done today at 00:42 UTC today at 00:43 UTC Setup snap "gtk-common-themes" aliases
Done today at 00:42 UTC today at 00:43 UTC Run install hook of "gtk-common-themes" snap if present
Done today at 00:42 UTC today at 00:43 UTC Start snap "gtk-common-themes" (1506) services
Done today at 00:42 UTC today at 00:43 UTC Run configure hook of "gtk-common-themes" snap if present
Done today at 00:42 UTC today at 00:43 UTC Run health check of "gtk-common-themes" snap
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:audio-record to snapd:audio-record
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:camera to snapd:camera
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:desktop to snapd:desktop
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:removable-media to snapd:removable-media
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:screen-inhibit-control to snapd:screen-inhibit-control
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:x11 to snapd:x11
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:browser-sandbox to snapd:browser-support
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:chromium-config to snapd:personal-files
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:network-bind to snapd:network-bind
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:unity7 to snapd:unity7
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:bluez to snapd:bluez
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:etc-chromium-browser-policies to snapd:system-files
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:joystick to snapd:joystick
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:cups-control to snapd:cups-control
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:system-packages-doc to snapd:system-packages-doc
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:u2f-devices to snapd:u2f-devices
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:upower-observe to snapd:upower-observe
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:audio-playback to snapd:audio-playback
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:gsettings to snapd:gsettings
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:network to snapd:network
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:opengl to snapd:opengl
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:sound-themes to gtk-common-themes:sound-themes
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:gtk-3-themes to gtk-common-themes:gtk-3-themes
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:home to snapd:home
Done today at 00:44 UTC today at 00:44 UTC Connect chromium:icon-themes to gtk-common-themes:icon-themes
Done today at 00:44 UTC today at 00:44 UTC Setup snap "chromium" (1373) security profiles for auto-connections
I managed to reproduce it while playing with the containers (the key point was to create 20.10 container which I missed previously; unfortunately I’ve no clear steps and couldn’t reproduce in a clean VM
Key observations - summary:
the host system is 20.10 , installed lxd 4.7 snap (rev 18137) on it
I created a mix of 18.04 and 20.10 lxc containers
I used lxdguiprofile.txt (from the tutorial linked above) for them, but I think this is irrelavant for the problem (it only sets up stuff around X11 / pulseaudio sockets).
in the 18.04 containers I installed firefox or chromium snaps (so that core18 base is pulled; not neccessary with 20.10 containers as they come with core18 already installed).
at some point, inside 20.10 container I saw there was a problem with core18 snap:
d????????? ? ? ? ? ? 1932
snapfuse process for this revision of core18 was running.
no denials and no snapfuse errors in the log.
This indeed looks like an issue with kernel / snapfuse and/or interaction with lxd. CC @stgraber for ideas.
Below commands have been run on the LXD host and the container. The OS for the LXD host and the containers are the same, Ubuntu 20.10. All commands returned the same output on the LXD host and the container.
lsb_release -a:
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.10
Release: 20.10
Codename: groovy
uname -a:
$ uname -a
Linux machinename 5.8.0-26-generic #27-Ubuntu SMP Wed Oct 21 22:29:16 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
snap version:
$ snap version
snap 2.47.1+20.10.1
snapd 2.47.1+20.10.1
series 16
ubuntu 20.10
kernel 5.8.0-26-generic
