From: Maxime Devos <maximedevos@telenet.be>
To: Attila Lendvai <attila@lendvai.name>, 53580@debbugs.gnu.org
Subject: bug#53580: /var/run/shepherd/socket is missing on an otherwise functional system
Date: Tue, 01 Feb 2022 19:28:03 +0000 [thread overview]
Message-ID: <04e30e30595ba96786a78c1dbc1768636b5c71e9.camel@telenet.be> (raw)
In-Reply-To: <BNbiqHqu6jP5GgHIZ0AMLhBo1O4baZdy21bgcUmGS1GqxOKnCHG_5uzzedymxwQsSFtL5gSw9Bppr1FXPoHDqIiKfe5K720Wb9Jivbsr_z4=@lendvai.name>
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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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next prev parent reply other threads:[~2022-02-02 0:20 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-27 11:32 bug#53580: /var/run/shepherd/socket is missing on an otherwise functional system Attila Lendvai
2022-01-27 12:13 ` bug#53580: (No Subject) Attila Lendvai
2022-02-01 11:06 ` Efraim Flashner
2022-02-01 19:28 ` Maxime Devos [this message]
2022-04-04 7:15 ` bug#53580: /var/run/shepherd/socket is missing on an otherwise functional system Attila Lendvai
2023-05-18 20:12 ` Ludovic Courtès
2023-05-27 10:33 ` bug#53580: shepherd's architecture Attila Lendvai
[not found] ` <Fe3OtPtYH2PHkXerCVPLsOIdvUw04jv5hYL_lms1t-V-JQ8vTvdHyu7Lk-PYfYIBns96NX34wxf8Yb3uNiiPGQzOMjB2hO7_yn3lrILV6fA=@lendvai.name>
2023-05-29 14:46 ` Brian Cully via Bug reports for GNU Guix
2023-06-06 15:16 ` Ludovic Courtès
2023-06-08 12:54 ` Csepp
2023-06-08 20:56 ` Attila Lendvai
2023-06-11 14:16 ` bug#53580: /var/run/shepherd/socket is missing on an otherwise functional system Ludovic Courtès
2023-06-11 14:18 ` Ludovic Courtès
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