;;; Copyright © 2013, 2014, 2015, 2016, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2017 Clément Lassieur <clement@lassieur.org>
;;; Copyright © 2018 Carlo Zancanaro <carlo@zancanaro.id.au>
+;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
#:use-module (guix store)
#:use-module (guix records)
#:use-module (guix derivations) ;imported-modules, etc.
+ #:use-module (guix utils)
#:use-module (gnu services)
#:use-module (gnu services herd)
#:use-module (gnu packages admin)
shepherd-service-lookup-procedure
shepherd-service-back-edges
- shepherd-service-upgrade))
+ shepherd-service-upgrade
+
+ user-processes-service-type))
;;; Commentary:
;;;
(extensions (list (service-extension boot-service-type
shepherd-boot-gexp)
(service-extension profile-service-type
- (const (list shepherd)))))))
+ (const (list shepherd)))))
+ (description
+ "Run the GNU Shepherd as PID 1---i.e., the operating system's first
+process. The Shepherd takes care of managing services such as daemons by
+ensuring they are started and stopped in the right order.")))
(define %shepherd-root-service
;; The root shepherd service, aka. PID 1. Its parameter is a list of
;; Default set of modules visible in a service's file.
`((shepherd service)
(oop goops)
- (guix build utils)
+ ((guix build utils) #:hide (delete))
(guix build syscalls)))
(define-record-type* <shepherd-service>
(define (scm->go file)
"Compile FILE, which contains code to be loaded by shepherd's config file,
and return the resulting '.go' file."
- (with-extensions (list shepherd)
- (computed-file (string-append (basename (scheme-file-name file) ".scm")
- ".go")
- #~(begin
- (use-modules (system base compile))
-
- ;; Do the same as the Shepherd's 'load-in-user-module'.
- (let ((env (make-fresh-user-module)))
- (module-use! env (resolve-interface '(oop goops)))
- (module-use! env (resolve-interface '(shepherd service)))
- (compile-file #$file #:output-file #$output
- #:env env)))
-
- ;; It's faster to build locally than to download.
- #:options '(#:local-build? #t
- #:substitutable? #f))))
+ (let-system (system target)
+ (with-extensions (list shepherd)
+ (computed-file (string-append (basename (scheme-file-name file) ".scm")
+ ".go")
+ #~(begin
+ (use-modules (system base compile)
+ (system base target))
+
+ ;; Do the same as the Shepherd's 'load-in-user-module'.
+ (let ((env (make-fresh-user-module)))
+ (module-use! env (resolve-interface '(oop goops)))
+ (module-use! env (resolve-interface '(shepherd service)))
+ (with-target #$(or target #~%host-type)
+ (lambda _
+ (compile-file #$file #:output-file #$output
+ #:env env)))))
+
+ ;; It's faster to build locally than to download.
+ #:options '(#:local-build? #t
+ #:substitutable? #f)))))
(define (shepherd-configuration-file services)
"Return the shepherd configuration file for SERVICES."
(default-environment-variables
'("PATH=/run/current-system/profile/bin"))
+ ;; Booting off a DVD, especially on a slow machine, can make
+ ;; everything slow. Thus, increase the timeout compared to the
+ ;; default 5s in the Shepherd 0.7.0. See
+ ;; <https://bugs.gnu.org/40572>.
+ (default-pid-file-timeout 30)
+
;; Arrange to spawn a REPL if something goes wrong. This is better
;; than a kernel panic.
(call-with-error-handling
(lambda ()
(apply register-services
- (map load-compiled '#$(map scm->go files)))))
+ (parameterize ((current-warning-port
+ (%make-void-port "w")))
+ (map load-compiled '#$(map scm->go files))))))
(format #t "starting services...~%")
(for-each (lambda (service)
(values to-unload to-restart))
+\f
+;;;
+;;; User processes.
+;;;
+
+(define %do-not-kill-file
+ ;; Name of the file listing PIDs of processes that must survive when halting
+ ;; the system. Typical example is user-space file systems.
+ "/etc/shepherd/do-not-kill")
+
+(define (user-processes-shepherd-service requirements)
+ "Return the 'user-processes' Shepherd service with dependencies on
+REQUIREMENTS (a list of service names).
+
+This is a synchronization point used to make sure user processes and daemons
+get started only after crucial initial services have been started---file
+system mounts, etc. This is similar to the 'sysvinit' target in systemd."
+ (define grace-delay
+ ;; Delay after sending SIGTERM and before sending SIGKILL.
+ 4)
+
+ (list (shepherd-service
+ (documentation "When stopped, terminate all user processes.")
+ (provision '(user-processes))
+ (requirement requirements)
+ (start #~(const #t))
+ (stop #~(lambda _
+ (define (kill-except omit signal)
+ ;; Kill all the processes with SIGNAL except those listed
+ ;; in OMIT and the current process.
+ (let ((omit (cons (getpid) omit)))
+ (for-each (lambda (pid)
+ (unless (memv pid omit)
+ (false-if-exception
+ (kill pid signal))))
+ (processes))))
+
+ (define omitted-pids
+ ;; List of PIDs that must not be killed.
+ (if (file-exists? #$%do-not-kill-file)
+ (map string->number
+ (call-with-input-file #$%do-not-kill-file
+ (compose string-tokenize
+ (@ (ice-9 rdelim) read-string))))
+ '()))
+
+ (define (now)
+ (car (gettimeofday)))
+
+ (define (sleep* n)
+ ;; Really sleep N seconds.
+ ;; Work around <http://bugs.gnu.org/19581>.
+ (define start (now))
+ (let loop ((elapsed 0))
+ (when (> n elapsed)
+ (sleep (- n elapsed))
+ (loop (- (now) start)))))
+
+ (define lset= (@ (srfi srfi-1) lset=))
+
+ (display "sending all processes the TERM signal\n")
+
+ (if (null? omitted-pids)
+ (begin
+ ;; Easy: terminate all of them.
+ (kill -1 SIGTERM)
+ (sleep* #$grace-delay)
+ (kill -1 SIGKILL))
+ (begin
+ ;; Kill them all except OMITTED-PIDS. XXX: We would
+ ;; like to (kill -1 SIGSTOP) to get a fixed list of
+ ;; processes, like 'killall5' does, but that seems
+ ;; unreliable.
+ (kill-except omitted-pids SIGTERM)
+ (sleep* #$grace-delay)
+ (kill-except omitted-pids SIGKILL)
+ (delete-file #$%do-not-kill-file)))
+
+ (let wait ()
+ ;; Reap children, if any, so that we don't end up with
+ ;; zombies and enter an infinite loop.
+ (let reap-children ()
+ (define result
+ (false-if-exception
+ (waitpid WAIT_ANY (if (null? omitted-pids)
+ 0
+ WNOHANG))))
+
+ (when (and (pair? result)
+ (not (zero? (car result))))
+ (reap-children)))
+
+ (let ((pids (processes)))
+ (unless (lset= = pids (cons 1 omitted-pids))
+ (format #t "waiting for process termination\
+ (processes left: ~s)~%"
+ pids)
+ (sleep* 2)
+ (wait))))
+
+ (display "all processes have been terminated\n")
+ #f))
+ (respawn? #f))))
+
+(define user-processes-service-type
+ (service-type
+ (name 'user-processes)
+ (extensions (list (service-extension shepherd-root-service-type
+ user-processes-shepherd-service)))
+ (compose concatenate)
+ (extend append)
+
+ ;; The value is the list of Shepherd services 'user-processes' depends on.
+ ;; Extensions can add new services to this list.
+ (default-value '())
+
+ (description "The @code{user-processes} service is responsible for
+terminating all the processes so that the root file system can be re-mounted
+read-only, just before rebooting/halting. Processes still running after a few
+seconds after @code{SIGTERM} has been sent are terminated with
+@code{SIGKILL}.")))
+
;;; shepherd.scm ends here
HCoop / jackhill / guix / guix.git / blobdiff