diff options
| -rw-r--r-- | doc/guix.texi | 26 | ||||
| -rw-r--r-- | gnu/services/base.scm | 54 | ||||
| -rw-r--r-- | gnu/tests/base.scm | 14 |
3 files changed, 88 insertions, 6 deletions
diff --git a/doc/guix.texi b/doc/guix.texi index 4b082c5f87..0ba034e822 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -10563,11 +10563,14 @@ Start,,, shepherd, The GNU Shepherd Manual}). For example: The above command, run as @code{root}, lists the currently defined services. The @command{herd doc} command shows a synopsis of the given -service: +service and its associated actions: @example # herd doc nscd Run libc's name service cache daemon (nscd). + +# herd doc nscd action invalidate +invalidate: Invalidate the given cache--e.g., 'hosts' for host name lookups. @end example The @command{start}, @command{stop}, and @command{restart} sub-commands @@ -10965,6 +10968,27 @@ The Kmscon package to use. Return a service that runs the libc name service cache daemon (nscd) with the given @var{config}---an @code{<nscd-configuration>} object. @xref{Name Service Switch}, for an example. + +For convenience, the Shepherd service for nscd provides the following actions: + +@table @code +@item invalidate +@cindex cache invalidation, nscd +@cindex nscd, cache invalidation +This invalidate the given cache. For instance, running: + +@example +herd invalidate nscd hosts +@end example + +@noindent +invalidates the host name lookup cache of nscd. + +@item statistics +Running @command{herd statistics nscd} displays information about nscd usage +and caches. +@end table + @end deffn @defvr {Scheme Variable} %nscd-default-configuration diff --git a/gnu/services/base.scm b/gnu/services/base.scm index 3409bd352c..228d3c5926 100644 --- a/gnu/services/base.scm +++ b/gnu/services/base.scm @@ -1252,18 +1252,57 @@ the tty to run, among other things." (string-concatenate (map cache->config caches))))))) +(define (nscd-action-procedure nscd config option) + ;; XXX: This is duplicated from mcron; factorize. + #~(lambda (_ . args) + ;; Run 'nscd' in a pipe so we can explicitly redirect its output to + ;; 'current-output-port', which at this stage is bound to the client + ;; connection. + (let ((pipe (apply open-pipe* OPEN_READ #$nscd + "-f" #$config #$option args))) + (let loop () + (match (read-line pipe 'concat) + ((? eof-object?) + (catch 'system-error + (lambda () + (zero? (close-pipe pipe))) + (lambda args + ;; There's a race with the SIGCHLD handler, which could + ;; call 'waitpid' before 'close-pipe' above does. If we + ;; get ECHILD, that means we lost the race, but that's + ;; fine. + (or (= ECHILD (system-error-errno args)) + (apply throw args))))) + (line + (display line) + (loop))))))) + +(define (nscd-actions nscd config) + "Return Shepherd actions for NSCD." + ;; Make this functionality available as actions because that's a simple way + ;; to run the right 'nscd' binary with the right config file. + (list (shepherd-action + (name 'statistics) + (documentation "Display statistics about nscd usage.") + (procedure (nscd-action-procedure nscd config "--statistics"))) + (shepherd-action + (name 'invalidate) + (documentation + "Invalidate the given cache--e.g., 'hosts' for host name lookups.") + (procedure (nscd-action-procedure nscd config "--invalidate"))))) + (define (nscd-shepherd-service config) "Return a shepherd service for CONFIG, an <nscd-configuration> object." - (let ((nscd.conf (nscd.conf-file config)) + (let ((nscd (file-append (nscd-configuration-glibc config) + "/sbin/nscd")) + (nscd.conf (nscd.conf-file config)) (name-services (nscd-configuration-name-services config))) (list (shepherd-service (documentation "Run libc's name service cache daemon (nscd).") (provision '(nscd)) (requirement '(user-processes)) (start #~(make-forkexec-constructor - (list #$(file-append (nscd-configuration-glibc config) - "/sbin/nscd") - "-f" #$nscd.conf "--foreground") + (list #$nscd "-f" #$nscd.conf "--foreground") ;; Wait for the PID file. However, the PID file is ;; written before nscd is actually listening on its @@ -1277,7 +1316,12 @@ the tty to run, among other things." (string-append dir "/lib")) (list #$@name-services)) ":"))))) - (stop #~(make-kill-destructor)))))) + (stop #~(make-kill-destructor)) + (modules `((ice-9 popen) ;for the actions + (ice-9 rdelim) + (ice-9 match) + ,@%default-modules)) + (actions (nscd-actions nscd nscd.conf)))))) (define nscd-activation ;; Actions to take before starting nscd. diff --git a/gnu/tests/base.scm b/gnu/tests/base.scm index 896d4a8f88..02882f4b46 100644 --- a/gnu/tests/base.scm +++ b/gnu/tests/base.scm @@ -335,6 +335,20 @@ info --version") (x (pk 'failure x #f)))) + (test-equal "nscd invalidate action" + '(#t) ;one value, #t + (marionette-eval '(with-shepherd-action 'nscd ('invalidate "hosts") + result + result) + marionette)) + + (test-equal "nscd invalidate action, wrong table" + '(#f) ;one value, #f + (marionette-eval '(with-shepherd-action 'nscd ('invalidate "xyz") + result + result) + marionette)) + (test-equal "host not found" #f (marionette-eval |