The supervise wrapper

With svclean, svscan runs the supervise wrapper instead of supervise itself.

• The wrapper sets $PATH to the value of $SUPERVISE_PATH (which was set by svclean-svscan to the original value of $PATH) and unsets $SUPERVISE_PATH.
• If $SUPERVISE_ENV is set, it uses that directory to configure its environment with envdir.
• If the file "svclean/redirect_2_1" exists within the service directory, then file descriptor 1 is dup'ed to descriptor 2, so supervise's error output will go to the service's own logger.
• If the file "svclean/keep_5" exists within the service directory, descriptor 5 is not closed; otherwise, it is. Likewise for svclean/keep_4 and descriptor 4, and for svclean/keep_3 and descriptor 3.
• If the file "svclean/shutdown" does not exist within the service directory, then descriptor 0 is put in blocking mode for loggers, and supervise is executed normally. Otherwise, for normal services (and for loggers whose descriptor 0 is not immediately readable), the wrapper exits without running supervise; for loggers whose descriptor 0 is immediately readable, descriptor 0 is made non-blocking and supervise is executed. Loggers are expected to exit after they read all currently available input and descriptor 0 is in non-blocking mode; the next read will result in EAGAIN. multilog behaves this way.

Add this command to your system boot scripts, to ensure that your services come up:

rm -f /service/*/svclean/shutdown /service/*/log/svclean/shutdown

The wrapper distinguishes normal services from loggers by checking whether descriptor 0 is a pipe. Do not run svclean-svscan with a pipe on descriptor 0.