Attila Lendvai schreef op do 27-01-2022 om 11:32 [+0000]: > (define (call-with-server-socket file-name proc) > "Call PROC, passing it a listening socket at FILE-NAME and deleting the > socket file at FILE-NAME upon exit of PROC. Return the values of PROC." > (let ((sock (open-server-socket file-name))) > (dynamic-wind > noop > (lambda () (proc sock)) > (lambda () > (close sock) > (catch-system-error (delete-file file-name)))))) > ``` > > maybe this is caused by some call/cc magic that causes an unwind that deletes > the file, but then continues?
Shepherd doesn't use call/cc anywhere. However, it does use _delimited_ continuations, even though only through let/ec and 'guard'/'catch'/... More generally, call/cc is typically unused in (Guile) Scheme code, and call-with-prompt / abort-to-prompt / shift / reset / % are used instead. My guess what happens: the start code of a shepherd service fails between 'fork' and 'exec', with an exception. The exception isn't caught (or is caught and reraised), so the 'out' guard of the 'dynamic-wind' is entered and the file representing the socket is deleted. If that's indeed the case, it might be a good idea to install some exception handlers in fork+exec-command and friends (including make-forkexec-constructor/container), to make shepherd more robust w.r.t. services failing to start. Greetings, Maxime.
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