winsw/docs/self-restarting-service.md

# Self-restarting Windows services

## Restart from the spawned process

To support self-restarting services, winsw exposes `WINSW_EXECUTABLE` environment variable into the forked process,
  which refers to the full path of *WinSW.exe* that's managing the service.
To restart the service from within, execute `%WINSW_EXECUTABLE% restart!`.
Note that you are invoking `restart!` command, not `restart` command.
This hidden command is a flavor of the `restart` operation,
  where winsw creates another winsw process in a separate process group,
  and restarts the service from there.

This additional indirection is necessary because WinSW will kill child processes recursively when it stops a service.
Windows Service Control Manager (SCM) doesn't provide the restart operation as an atomic operation either, so winsw implements restart by a sequence of stop and start.
The second winsw process in a separate process group ensures that winsw can survive this massacre to execute the start call.