Build Error Due to Changes in 'udevadm' Output

When a make command for the Meinberg driver package for Linux is run, execution fails with an error message like:

make: Entering directory '/home/martin/mbgtools-lx/mbgclock'
/bin/sh: -c: line 0: syntax error near unexpected token `('
/bin/sh: -c: line 0: `if [ 239 (239-41.el8_3.1) -lt 055 ]; then echo "55-mbgclock.rules.before-udev-055"; else echo "55-mbgclock.rules"; fi; '

This has been observed on the CentOS8 distribution. Because CentOS is a free clone of Red Hat Enterprise Linux, this will probably also occur on Red Hat Enterprise Linux 8 (i.e. RHEL8), and may also occur on some versions of Fedora Linux, which is also maintained by RedHat.

The command udevadm –version is called from the Makefile to determine the version of the udev system provided by the distro.

For many years, and across all distros we have seen before, the output of the command used to be a simple numeric string like 221. However, in the affected Linux distros, the output of the command is something like 239 (239-41.el8_3.1) instead, and the extended string causes confusion when it is evaluated.

The symptoms described above may occur with version 4.2.14 of the Meinberg driver packages for Linux, and with all earlier versions.

Please note there is no problem with the driver itself, it's just with the commands used to build the driver package.

Possible ways to fix this problem for now is to

• either use the stable driver package 4.2.14 and call each make command with an additional parameter
• or use the devel branch of the git repo of the driver package.

The stable version 4.2.14 of the driver package is available from the Meinberg web page at

• https://www.meinbergglobal.com/english/sw/#linux

or at the head of the master branch of the git repository at

• https://git.meinbergglobal.com/drivers/mbgtools-lx.git

If this driver package is used, it is possible to avoid the problem if a specific command line option is passed to each make command, e.g.:

make UDEV_VER=239
make UDEV_VER=239 clean
make UDEV_VER=239 install

The numeric version code doesn't really matter. It can be anything greater than “55”.

A real fix is already available in a prerelease version of the driver package which is available on the devel branch of the git repo of the driver package.

So if you use git to update the driver package, you can use the following commands to clone and build the driver package:

git clone https://git.meinbergglobal.com/drivers/mbgtools-lx.git
cd mbgtools-lx
git checkout devel

After this, it should be possible to build the driver package as described in the README file, without additional options for the make command.

— Martin Burnicki martin.burnicki@meinberg.de, last updated 2021-01-27