community/lxcfs: Modprobe modules instead of failing when absent

[nero]

Previously, lxcfs failed when the kernel modules were not listed the lsmod
output. Built-in kernel modules never show up in lsmod, thus the service
could not be properly started on such systems.

Fixes #9214.

[nero]

Ping @itoffshore

[itoffshore]

needs tabs instead of spaces in the patch to fix the alignment of return 1

running git diff before making a commit shows these alignment type errors.

[nero]

Branch updated.

[ncopa]

I don' think this will work. modprobe will return an error when the filesystem is compiled in to kernel instead of module: modprobe: FATAL: Module ... not found in directory /lib/modules/4.14.65-0-vanilla

We need to check if the filessystem is available in kernel and try modprobe if it isnt. Something like:

diff --git a/community/lxcfs/lxcfs.initd b/community/lxcfs/lxcfs.initd
index 1a6e9c9759..496d6156fb 100644
--- a/community/lxcfs/lxcfs.initd
+++ b/community/lxcfs/lxcfs.initd
@@ -19,14 +19,11 @@ depend() {
 }
 
 start_pre() {
-       local module=
+       local filesystem=
        checkpath --directory ${VARDIR}
-       for module in fuse autofs4; do
-               if ! $(lsmod | grep -q ^$module); then
-                       eerror "Enable module: $module"
-                       eerror "modprobe $module"
-                       eerror "echo $module >> /etc/modules"
-                       eend 1
+       for filesystem in fuse autofs4; do
+               if ! grep -q -w $filesystem /proc/filesystems; then
+                       modprobe $filesystem || return 1
                fi
        done
 }

modprobe will print error message so I don't think we need print any error message with eerror.

[nero]

@ncopa There is /lib/modules/$(uname -r)/modules.builtin.bin, which contains a list of built-in modules. Modprobe uses that as ignore list.

See second headline here:

modules.builtin

This file lists all modules that are built into the kernel. This is used
by modprobe to not fail when trying to load something builtin.

You can confirm this behavior by modprobing brd on alpine, which is not present in the modules directory:

nyu:~# modprobe brd; echo $?
0
nyu:~# find /lib/modules/$(uname -r) -name '*brd*'
nyu:~#

[ncopa]

2 files changed, 3 insertions(+), 11 deletions(-)

❤️

[algitbot]

Merged in c0513a0 by @ncopa. Thanks for your contribution!

(This pull request has been closed automatically by GitHub PR Closer. If you think that it’s not resolved yet, please add a comment.)

[yarons]

You guys ares awesome! Thanks @ncopa, I'm a big fan!