Run linuxcnc as root user

Hi
I am tryinh to run linuxcnc on fedora using copr.fedorainfracloud.org/coprs/dwrobel/linuxcnc/ link
Now I am trying to run it as root user because I don't want to give root access to main user.
after running linuxcnc command in terminal I am getting

LINUXCNC - 2.10.0-0.100.20231213git6d8161a.fc38
Machine configuration directory is '/usr/share/doc/linuxcnc/examples/sample-configs/sim/axis'
Machine configuration file is 'axis.ini'
Starting LinuxCNC...
linuxcncsvr (261738) emcsvr: machine 'LinuxCNC-HAL-SIM-AXIS'  version '1.1'
linuxcnc TPMOD=tpmod HOMEMOD=homemod EMCMOT=motmod
Refusing to run as root without fallback UID specified
To run under a debugger with I/O, use e.g.,
    sudo env RTAPI_UID=`id -u` RTAPI_FIFO_PATH=$HOME/.rtapi_fifo gdb /usr/bin/rtapi_app
<commandline>:0: waitpid failed /usr/bin/rtapi_app tpmod
<commandline>:0: /usr/bin/rtapi_app exited without becoming ready
<commandline>:0: insmod for tpmod failed, returned -1
Refusing to run as root without fallback UID specified
To run under a debugger with I/O, use e.g.,
    sudo env RTAPI_UID=`id -u` RTAPI_FIFO_PATH=$HOME/.rtapi_fifo gdb /usr/bin/rtapi_app
<commandline>:0: waitpid failed /usr/bin/rtapi_app homemod
<commandline>:0: /usr/bin/rtapi_app exited without becoming ready
<commandline>:0: insmod for homemod failed, returned -1
milltask (261749) task: machine 'LinuxCNC-HAL-SIM-AXIS'  version '1.1'
halui (261754) halui: machine 'LinuxCNC-HAL-SIM-AXIS'  version '1.1'
Found file(lib): /usr/share/linuxcnc/hallib/core_sim.hal
Refusing to run as root without fallback UID specified
To run under a debugger with I/O, use e.g.,
    sudo env RTAPI_UID=`id -u` RTAPI_FIFO_PATH=$HOME/.rtapi_fifo gdb /usr/bin/rtapi_app
/usr/share/linuxcnc/hallib/core_sim.hal:5: waitpid failed /usr/bin/rtapi_app trivkins
/usr/share/linuxcnc/hallib/core_sim.hal:5: /usr/bin/rtapi_app exited without becoming ready
/usr/share/linuxcnc/hallib/core_sim.hal:5: insmod for trivkins failed, returned -1
Shutting down and cleaning up LinuxCNC...
USRMOT: ERROR: command 30 timeout
emcMotionInit: emcTrajInit failed
USRMOT: ERROR: command 3 timeout
Refusing to run as root without fallback UID specified
To run under a debugger with I/O, use e.g.,
    sudo env RTAPI_UID=`id -u` RTAPI_FIFO_PATH=$HOME/.rtapi_fifo gdb /usr/bin/rtapi_app
LinuxCNC terminated with an error.  You can find more information in the log:
    /root/linuxcnc_debug.txt
and
    /root/linuxcnc_print.txt
as well as in the output of the shell command 'dmesg' and in the terminal


File: /root/linuxcnc_debug.txt


  260460
  260470
  Stopping realtime threads
  Unloading hal components


File: /root/linuxcnc_print.txt

  RUN_IN_PLACE=no
  LINUXCNC_DIR=
  LINUXCNC_BIN_DIR=/usr/bin
  LINUXCNC_TCL_DIR=/usr/lib64/tcl8.6/linuxcnc2.10.0
  LINUXCNC_SCRIPT_DIR=
  LINUXCNC_RTLIB_DIR=/usr/lib/linuxcnc/modules
  LINUXCNC_CONFIG_DIR=
  LINUXCNC_LANG_DIR=/usr/lib/tcltk/linuxcnc/msgs
  INIVAR=inivar
  HALCMD=halcmd
  LINUXCNC_EMCSH=/usr/bin/wish8.6
  INIFILE=/usr/share/doc/linuxcnc/examples/sample-configs/sim/axis/axis.ini
  VERSION=1.1
  PARAMETER_FILE=sim.var
  TPMOD=
  HOMEMOD=
  TASK=milltask
  HALUI=halui
  DISPLAY=axis
  COORDINATES=X Y Z
  KINEMATICS=trivkins
  Starting LinuxCNC server program: linuxcncsvr
  Loading Real Time OS, RTAPI, and HAL_LIB modules
  Starting TASK program: milltask
  Starting HAL User Interface program: halui
  Removing HAL_LIB, RTAPI, and Real Time OS modules
  Removing NML shared memory segments

 

The biggest issue is the mess that can be made of the file system.


TBH the OP confuses me.

I would think that would lower rather than raise security.

I have one root and one non-root user. So the idea is root user is running linuxcnc and non-root user is sending commands via python api. So I have all security issues under control.

User has no access to file system i have one service running which is doing all the work

I am taking care of the security. Giving root level access to non-root user is more risky for me.

With regards to “security” with Linuxcnc.
It really comes down to who has access to the machine. I feel once the “bad guy” has physical access it’s the damage that can be done to the cnc machine whilst running linuxcnc. It’s not like you’re running a server with sensitive info, you’re running a piece of equipment that can either harm personnel or damage itself.
First rule of security is physical security of the machine. Once an unauthorised person get physical access to your cnc machine I can guarantee it’s not the file system on the computer you’ll be “shitting bricks” about.

I might be wrong but from my memory linuxcnc does not like being run by the root user. Certainly compiling hte source as root creats all sorts of issues. I found that out the hard way.

What you could do is build linuxcnc from source via RIP as a specific user and that will place all of the executables in that users home folder. The linuxcnc folder will also be there too. Its pretty easy to do. I did a tutorial of it. 

So other users can be set up as another user and they will never see any access to linuxcnc and root is not used at all.