Boinc client doesn't have protection against accidental running multiple instances on sam,e datadir

[kotenok2000]

Describe the bug
Boinc client doesn't have protection against accidental running multiple instances with same datadir
Steps To Reproduce

1. Install https://boinc.berkeley.edu/dl/boinc_ubuntu_7.16.6_x86_64-pc-linux-gnu.sh
2. replace files with files from https://boinc.berkeley.edu/dl/linux/stable/jammy/pool/main/b/boinc-client/boinc-client_8.0.2-715_amd64.deb and https://boinc.berkeley.edu/dl/linux/stable/jammy/pool/main/b/boinc-manager/boinc-manager_8.0.2-715_amd64.deb
3. run it with ./run_client
4. switch to a new terminal.
5. run it again with ./run_client
   Expected behavior
   Boinc client detects it is already running with same datadir and closes
   Screenshots
   If applicable, add screenshots to help explain your problem.

System Information

• OS: Ubuntu 22.04
• BOINC Version: boinc-client_8.0.2-715

Additional context
Add any other context about the problem here.

[davidpanderson]

I couldn't repro this on Ubuntu 18.04 and BOINC 8.1.0;
the 2nd instance prints ' Another instance of BOINC is running.' and exits.

[kotenok2000]

It happens when i run it with
cd "/home/user/BOINC" && exec boinc --gui_rpc_port 31417 $@

[davidpanderson]

When the BOINC client starts, it tries to acquire a lock on the file 'lockfile'
in the current directory (i.e. the data directory).

This prevents 2 clients from running in the same data directory.
It doesn't prevent 2 clients from running on the same host.

Are your 2 clients actually running in the same directory?
Check for something like
04-Jan-2025 14:45:08 [---] Data directory: /home/boincadm/boinc_test
at the start of the event log.
Are the directories the same?

[kotenok2000]

I see this when running another instance in same directory.

For some reason /home/user/BOINC/lockfile was last modified in Aug 28 2023
I am running it in WSL1. Maybe it is the cause?

[davidpanderson]

WSL could be the problem.
There are reports that it doesn't implement fctnl(fd, F_SETLK)
https://stackoverflow.com/questions/59243106/why-fcntl-is-not-blocking-on-f-setlkw-in-wsl
(this is from 2019 and it's talking about WSL 2, but I suspect that problem exists in WSL 1)

File locking probably work in WSL 2. It's critical for many Linux programs.