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| author | Ludovic Courtès <ludo@gnu.org> | 2020-03-19 11:14:29 +0100 |
|---|---|---|
| committer | Ludovic Courtès <ludo@gnu.org> | 2020-03-22 12:42:51 +0100 |
| commit | 9a067fe7ee3978a2f4f0ca0e89965f0fe49f4ce8 (patch) | |
| tree | b72bc37a7957d0f980ab9910569417657e4cba39 /guix/build | |
| parent | 1550db6fd47f84672b5bf554be922b96da2be3d8 (diff) | |
| download | gnu-guix-9a067fe7ee3978a2f4f0ca0e89965f0fe49f4ce8.tar gnu-guix-9a067fe7ee3978a2f4f0ca0e89965f0fe49f4ce8.tar.gz | |
syscalls: 'with-file-lock' re-grabs lock when reentering its dynamic extent.
* 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.
Diffstat (limited to 'guix/build')
| -rw-r--r-- | guix/build/syscalls.scm | 64 |
1 files 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 |