From: "Ludovic Courtès" <ludo@gnu.org>
To: 40130@debbugs.gnu.org
Cc: "Ludovic Courtès" <ludo@gnu.org>
Subject: [bug#40130] [PATCH 1/8] syscalls: 'with-file-lock' re-grabs lock when reentering its dynamic extent.
Date: Thu, 19 Mar 2020 12:02:45 +0100 [thread overview]
Message-ID: <20200319110252.5081-1-ludo@gnu.org> (raw)
In-Reply-To: <20200319105642.4830-1-ludo@gnu.org>
* guix/build/syscalls.scm (call-with-file-lock)
(call-with-file-lock/no-wait): Initialize PORT in the 'dynamic-wind'
"in" handler. This allows us to re-enter a captured continuation and
have the lock grabbed anew.
---
guix/build/syscalls.scm | 64 +++++++++++++++++++++--------------------
1 file changed, 33 insertions(+), 31 deletions(-)
diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm
index ae79a9708f..0938ec0ff1 100644
--- a/guix/build/syscalls.scm
+++ b/guix/build/syscalls.scm
@@ -1104,47 +1104,49 @@ exception if it's already taken."
#t)
(define (call-with-file-lock file thunk)
- (let ((port (catch 'system-error
- (lambda ()
- (lock-file file))
- (lambda args
- ;; When using the statically-linked Guile in the initrd,
- ;; 'fcntl-flock' returns ENOSYS unconditionally. Ignore
- ;; that error since we're typically the only process running
- ;; at this point.
- (if (= ENOSYS (system-error-errno args))
- #f
- (apply throw args))))))
+ (let ((port #f))
(dynamic-wind
(lambda ()
- #t)
+ (set! port
+ (catch 'system-error
+ (lambda ()
+ (lock-file file))
+ (lambda args
+ ;; When using the statically-linked Guile in the initrd,
+ ;; 'fcntl-flock' returns ENOSYS unconditionally. Ignore
+ ;; that error since we're typically the only process running
+ ;; at this point.
+ (if (= ENOSYS (system-error-errno args))
+ #f
+ (apply throw args))))))
thunk
(lambda ()
(when port
(unlock-file port))))))
(define (call-with-file-lock/no-wait file thunk handler)
- (let ((port (catch #t
- (lambda ()
- (lock-file file #:wait? #f))
- (lambda (key . args)
- (match key
- ('flock-error
- (apply handler args)
- ;; No open port to the lock, so return #f.
- #f)
- ('system-error
- ;; When using the statically-linked Guile in the initrd,
- ;; 'fcntl-flock' returns ENOSYS unconditionally. Ignore
- ;; that error since we're typically the only process running
- ;; at this point.
- (if (= ENOSYS (system-error-errno (cons key args)))
- #f
- (apply throw key args)))
- (_ (apply throw key args)))))))
+ (let ((port #f))
(dynamic-wind
(lambda ()
- #t)
+ (set! port
+ (catch #t
+ (lambda ()
+ (lock-file file #:wait? #f))
+ (lambda (key . args)
+ (match key
+ ('flock-error
+ (apply handler args)
+ ;; No open port to the lock, so return #f.
+ #f)
+ ('system-error
+ ;; When using the statically-linked Guile in the initrd,
+ ;; 'fcntl-flock' returns ENOSYS unconditionally. Ignore
+ ;; that error since we're typically the only process running
+ ;; at this point.
+ (if (= ENOSYS (system-error-errno (cons key args)))
+ #f
+ (apply throw key args)))
+ (_ (apply throw key args)))))))
thunk
(lambda ()
(when port
--
2.25.1
next prev parent reply other threads:[~2020-03-19 11:04 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-19 10:56 [bug#40130] [PATCH 0/8] Add 'with-build-handler' and use it to improve UI feedback Ludovic Courtès
2020-03-19 11:02 ` Ludovic Courtès [this message]
2020-03-19 11:02 ` [bug#40130] [PATCH 2/8] store: Add 'with-build-handler' Ludovic Courtès
2020-03-19 11:02 ` [bug#40130] [PATCH 3/8] ui: Add a notification build handler Ludovic Courtès
2020-03-19 11:02 ` [bug#40130] [PATCH 4/8] guix build: Use 'with-build-handler' Ludovic Courtès
2020-03-19 11:02 ` [bug#40130] [PATCH 5/8] deploy: " Ludovic Courtès
2020-03-19 11:02 ` [bug#40130] [PATCH 6/8] pack: " Ludovic Courtès
2020-03-19 11:02 ` [bug#40130] [PATCH 7/8] guix package, pull: " Ludovic Courtès
2020-03-19 11:02 ` [bug#40130] [PATCH 8/8] guix system: " Ludovic Courtès
2020-03-22 11:44 ` bug#40130: [PATCH 0/8] Add 'with-build-handler' and use it to improve UI feedback Ludovic Courtès
2020-03-22 12:44 ` [bug#40130] " Ricardo Wurmus
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: https://guix.gnu.org/
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200319110252.5081-1-ludo@gnu.org \
--to=ludo@gnu.org \
--cc=40130@debbugs.gnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.savannah.gnu.org/cgit/guix.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).