Snap mount namespace does not contain a specific directory. How do I add /usr/lib/doublecmd/ to snap Firefox's mount namespace without causing problems? Is there a "refresh" command that adjusts for non-snap changes? Or is there a file that determines what appears in a mount namespace? I want to do this system-wide if possible, but others may want to do this at the user level.
Terminal lists the doublecmd directory, snap Firefox file:// does not.
I kind of understand mount namespaces and that snap uses them for security, but I am not finding anything (or maybe not understanding what I'm finding) to add a specific directory to a snap mount namespace. I also consider the possibility that I am looking at this all wrong.
Plan B is to un-install all snap applications and snap itself, then install the applications using apt if possible. But Ubuntu appears to be committed to using snap ...
details
Ubuntu 22.10 AMD64, tried to use Double Commander's 1.0.8 help, which is browser based. Snap 2.58.2 Firefox 110.0, returns:
File not found
Firefox can’t find the file at /usr/lib/doublecmd/doc/en/index.html.
Check the file name for capitalization or other typing errors.
Check to see if the file was moved, renamed or deleted.
The file is there. Shortened the Firefox file:// spec, finally got to:
Index of file:///usr/lib/
Up to higher level directory
Name Size Last Modified
NetworkManager 1/25/23 22:46:21 PST
apparmor 1/25/23 22:46:21 PST
binfmt.d 9/8/22 02:58:15 PDT
File:clock-epoch 1/25/23 22:46:06 PST
cloud-init 1/25/23 22:46:21 PST
core 1/25/23 22:46:21 PST
cryptsetup 1/25/23 22:46:21 PST
dbus-1.0 1/25/23 22:46:21 PST
missing doublecmd should appear here
environment.d 1/25/23 22:46:21 PST
finalrd 1/25/23 22:46:21 PST
<snip>
Compare to terminal:
$ ll /usr/lib/
total 1308
drwxr-xr-x 113 root root 4096 Feb 17 06:42 ./
drwxr-xr-x 14 root root 4096 Oct 20 00:06 ../
drwxr-xr-x 2 root root 4096 Oct 20 00:07 apg/
drwxr-xr-x 2 root root 4096 Oct 20 00:07 apparmor/
drwxr-xr-x 5 root root 4096 Oct 20 00:07 apt/
drwxr-xr-x 3 root root 4096 Oct 20 00:07 aspell/
drwxr-xr-x 2 root root 4096 Oct 11 08:51 binfmt.d/
drwxr-xr-x 2 root root 4096 Feb 17 06:42 binfmt-support/
drwxr-xr-x 2 root root 4096 Oct 20 00:07 bluetooth/
drwxr-xr-x 2 root root 4096 Oct 20 00:08 brltty/
-rwxr-xr-x 1 root root 1075 Dec 8 2021 cnf-update-db*
-rwxr-xr-x 1 root root 3565 Dec 8 2021 command-not-found*
drwxr-xr-x 2 root root 4096 Oct 20 00:07 console-setup/
lrwxrwxrwx 1 root root 21 Jan 22 06:58 cpp -> /etc/alternatives/cpp*
drwxr-xr-x 2 root root 4096 Oct 20 00:08 crda/
drwxr-xr-x 10 root root 4096 Oct 20 00:07 cups/
drwxr-xr-x 2 root root 4096 Jan 22 07:51 dbus-1.0/
drwxr-xr-x 4 root root 4096 Jan 23 16:40 debug/
drwxr-xr-x 4 root root 4096 Jan 22 16:33 doublecmd/
drwxr-xr-x 3 root root 4096 Oct 20 00:07 dpkg/
drwxr-xr-x 3 root root 4096 Oct 20 00:07 emacsen-common/
drwxr-xr-x 2 root root 4096 Jan 22 07:51 environment.d/
drwxr-xr-x 7 root root 4096 Oct 20 00:07 evolution-data-server/
drwxr-xr-x 2 root root 4096 Oct 20 00:07 file/
drwxr-xr-x 3 root root 4096 Oct 20 00:08 firewalld/
drwxr-xr-x 90 root root 49152 Jan 22 07:51 firmware/
<snip>
$ lsb_release --all
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 22.10
Release: 22.10
Codename: kinetic
$
Double Commander -> Help -> About:
Version: 1.0.8
Revision: 191
Commit: ee1f44b3c
Build date: 2022/10/10
Lazarus: 2.2.0.4
FPC: 3.2.2
Platform: x86_64-Linux-gtk2
OS version: Ubuntu 22.10
Widgetset library: GTK 2.24.33
$ snap version
snap 2.58.2
snapd 2.58.2
series 16
ubuntu 22.10
kernel 5.19.0-31-generic
$
$ findmnt | grep firefox
│ │ └─/run/snapd/ns/firefox.mnt nsfs[mnt:[4026532891]] nsfs rw
├─/snap/firefox/2311 /dev/loop5 squashfs ro,nodev,relatime,errors=continue
├─/snap/firefox/2356 /dev/loop6 squashfs ro,nodev,relatime,errors=continue
$
