Symlink error when running simulation example

[rdlynx19]

Hello,
I followed the instructions on the README to setup the docker container in VS Code. After building and opening the container in VS Code, when I run the test commands:

cd
cd PX4-Autopilot/
make px4_sitl gz_x500

I get the following error in the VS Code terminal:

ros@tokyo:~/PX4-Autopilot$ make px4_sitl gz_x500
[0/1] cd /home/ros/PX4-Autopilot/build/px4_sitl_default/src/modul...EL=gz_x500 /home/ros/PX4-Autopilot/build/px4_sitl_default/bin/px4
ERROR [px4] Error creating symlink /home/ros/PX4-Autopilot/build/px4_sitl_default/etc -> /home/ros/PX4-Auto
FAILED: src/modules/simulation/gz_bridge/CMakeFiles/gz_x500 /home/ros/PX4-Autopilot/build/px4_sitl_default/src/modules/simulation/gz_bridge/CMakeFiles/gz_x500 
cd /home/ros/PX4-Autopilot/build/px4_sitl_default/src/modules/simulation/gz_bridge && /usr/bin/cmake -E env PX4_SIM_MODEL=gz_x500 /home/ros/PX4-Autopilot/build/px4_sitl_default/bin/px4
ninja: build stopped: subcommand failed.
make: *** [Makefile:232: px4_sitl] Error 1

I tried running the command as sudo but it still does not work.

ros@tokyo:~/PX4-Autopilot$ sudo make px4_sitl gz_x500
[0/1] cd /home/ros/PX4-Autopilot/build/px4_sitl_default/src/modul...EL=gz_x500 /home/ros/PX4-Autopilot/build/px4_sitl_default/bin/px4
ERROR [px4] get_server_running: failed to create lock file: /tmp/px4_lock-0, reason=Permission denied
ERROR [px4] Failed to get server status
FAILED: src/modules/simulation/gz_bridge/CMakeFiles/gz_x500 /home/ros/PX4-Autopilot/build/px4_sitl_default/src/modules/simulation/gz_bridge/CMakeFiles/gz_x500 
cd /home/ros/PX4-Autopilot/build/px4_sitl_default/src/modules/simulation/gz_bridge && /usr/bin/cmake -E env PX4_SIM_MODEL=gz_x500 /home/ros/PX4-Autopilot/build/px4_sitl_default/bin/px4
ninja: build stopped: subcommand failed.
make: *** [Makefile:232: px4_sitl] Error 1

I would appreciate your help in solving this issue.

[edouardrolland]

@rdlynx19 After a quick look, it might be because the /tmp directory is not writable by your user:

Check if it is writable with this:

ls -ld /tmp

You should see something like this:
drwxrwxrwt 10 root root 4096 Jan 7 10:00 /tmp

If not, fix it with:

sudo chmod 1777 /tmp

---

Also, check for leftover PX4 lock files in /tmp. Look for them with:

ls -l /tmp/px4_lock-*

If any exist, remove them (ensure no other PX4 instances are running):

sudo rm /tmp/px4_lock-*

---

It’s recommended not to run PX4 SITL with sudo. Instead, run it as your user:

make px4_sitl gz_x500

---

If the issue persists, clean and rebuild the project:

make clean
make px4_sitl_default
make px4_sitl gz_x500

---

Finally, ensure your user has proper ownership of the PX4 directory:

sudo chown -R $USER:$USER /home/ros/PX4-Autopilot

---

Let me know if this resolves your issue!

[rdlynx19]

Hi @edouardrolland
I checked the command

ls -ld /tmp

and it returns me an output similar to the one you mentioned.
I have also cleaned the leftover PX4 files in the /tmp directory

Running make px4_sitl gz_x500 still throws the same error

I am unable to clean the project, on running make clean I get a bunch of Permission denied messages. (there are more but I can't seem to copy all of them)

rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/uAvionix/testsuite.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/checksum.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/protocol.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/mavlink_helpers.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/minimal/mavlink_msg_heartbeat.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/minimal/minimal.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/minimal/mavlink_msg_protocol_version.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/minimal/version.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/minimal/mavlink.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/minimal/testsuite.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/standard/standard.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/standard/version.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/standard/mavlink.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/mavlink/standard/testsuite.h': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/parameters.json': Permission denied
rm: cannot remove '/home/ros/PX4-Autopilot/build/px4_sitl_default/.ninja_log': Permission denied
fatal: detected dubious ownership in repository at '/home/ros/PX4-Autopilot'
To add an exception for this directory, call:

        git config --global --add safe.directory /home/ros/PX4-Autopilot
make: *** [Makefile:497: clean] Error 128

Lastly, trying to change the ownership does not return anything

ros@tokyo:~/PX4-Autopilot$ sudo chown -R ros:ros /home/ros/PX4-Autopilot

I think bash gets stuck in some way.