Yelp/dumb-init

"Unable to detach from controlling tty (errno=25 Not a tty)"

christianinsert opened this issue · 3 comments

christianinsert commented

I get quite often the error Unable to detach from controlling tty (errno=25 Not a tty). I could not find any documentation about this. What does it mean? Should I be worried? What can I do to fix it?

asottile commented

this message is normal in verbose mode -- it is a debug message showing that it is not attached to a tty

$ echo hi | dumb-init --verbose echo hello
[dumb-init] Unable to detach from controlling tty (errno=25 Inappropriate ioctl for device).
[dumb-init] Child spawned with PID 37933.
[dumb-init] Unable to attach to controlling tty (errno=25 Inappropriate ioctl for device).
[dumb-init] setsid complete.
hello
[dumb-init] Received signal 17.
[dumb-init] A child with PID 37933 exited with exit status 0.
[dumb-init] Forwarded signal 15 to children.
[dumb-init] Child exited with status 0. Goodbye.
  • 👍1
christianinsert commented

Thanks for the info! (If more people get confused about that it might be worth adding to the docs?)

asottile commented

I'm not sure why one would be confused -- it's only there in --verbose mode, it's not messaged as an error, it doesn't terminate the process.