Missing PID file check

[mephinet]

Describe the bug
I think I found a bug in gpclient: Unintentionally, I started "gpclient connect" while it was already running in another terminal. To my surprise, the second gpclient did not exit immediately, but created another tunnel, resulting in my network no longer being functional. I was unable to kill the two processes, and had to revert to "killall -9 gpclient" to get a working network again.

Expected behavior
From reading the log output, I know that gpclient creates a pid file:

https://github.com/yuezk/GlobalProtect-openconnect/blob/a6414533887fa3167d93b073c6308deb20ecd469/apps/gpclient/src/connect.rs#L413C10-L418C2

However, I could not find any code that checks for the existence of this pid file, and if it exists, checks whether a process with this PID is running.

Logs
in terminal 1:

[2024-11-28T09:05:46Z INFO  gpclient::cli] gpclient started: 2.3.9 (2024-11-02)
...
[2024-11-28T09:05:48Z INFO  openconnect::vpn] Connected to VPN, pipe_fd: 11
[2024-11-28T09:05:48Z INFO  gpclient::connect] Wrote PID 9290 to /var/run/gpclient.lock

in terminal 2:

[2024-11-28T09:05:56Z INFO  gpclient::cli] gpclient started: 2.3.9 (2024-11-02)
...
[2024-11-28T09:05:58Z INFO  openconnect::vpn] Connected to VPN, pipe_fd: 11
[2024-11-28T09:05:58Z INFO  gpclient::connect] Wrote PID 9954 to /var/run/gpclient.lock

Environment:

• OS: Arch Linux
• Desktop Environment: i3
• /usr/bin/gnome-keyring-daemon --foreground --components=pkcs11,secrets --control-directory=/run/user/1000/keyring
• Is remote SSH? No

[yuezk]

Thanks for the reporting, I will fix it.