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-rw-r--r--gnu/services/base.scm93
-rw-r--r--gnu/services/xorg.scm2
2 files changed, 90 insertions, 5 deletions
diff --git a/gnu/services/base.scm b/gnu/services/base.scm
index 9561995243..ae538ea41c 100644
--- a/gnu/services/base.scm
+++ b/gnu/services/base.scm
@@ -22,14 +22,17 @@
#:use-module (gnu system linux) ; 'pam-service', etc.
#:use-module (gnu packages admin)
#:use-module ((gnu packages base)
- #:select (glibc-final))
+ #:select (glibc-final %final-inputs))
+ #:use-module (gnu packages linux)
#:use-module (gnu packages package-management)
#:use-module (guix gexp)
#:use-module (guix monads)
#:use-module (srfi srfi-1)
#:use-module (srfi srfi-26)
#:use-module (ice-9 format)
- #:export (host-name-service
+ #:export (root-file-system-service
+ user-processes-service
+ host-name-service
mingetty-service
nscd-service
syslog-service
@@ -43,6 +46,81 @@
;;;
;;; Code:
+(define (root-file-system-service)
+ "Return a service whose sole purpose is to re-mount read-only the root file
+system upon shutdown (aka. cleanly \"umounting\" root.)
+
+This service must be the root of the service dependency graph so that its
+'stop' action is invoked when dmd is the only process left."
+ (define coreutils
+ (car (assoc-ref %final-inputs "coreutils")))
+
+ (with-monad %store-monad
+ (return
+ (service
+ (documentation "Take care of the root file system.")
+ (provision '(root-file-system))
+ (start #~(const #t))
+ (stop #~(lambda _
+ ;; Return #f if successfully stopped.
+ (system* (string-append #$coreutils "/bin/sync"))
+
+ (call-with-blocked-asyncs
+ (lambda ()
+ (let ((null (%make-void-port "w")))
+ ;; Close 'dmd.log'.
+ (display "closing log\n")
+ ;; XXX: Ideally we'd use 'stop-logging', but that one
+ ;; doesn't actually close the port as of dmd 0.1.
+ (close-port (@@ (dmd comm) log-output-port))
+ (set! (@@ (dmd comm) log-output-port) null)
+
+ ;; Redirect the default output ports..
+ (set-current-output-port null)
+ (set-current-error-port null)
+
+ ;; Close /dev/console.
+ (for-each close-fdes '(0 1 2))
+
+ ;; At this points, there are no open files left, so the
+ ;; root file system can be re-mounted read-only.
+ (not (zero?
+ (system* (string-append #$util-linux "/bin/mount")
+ "-n" "-o" "remount,ro"
+ "-t" "dummy" "dummy" "/"))))))))
+ (respawn? #f)))))
+
+(define* (user-processes-service #:key (grace-delay 2))
+ "Return the service that 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 GRACE-DELAY seconds after SIGTERM
+has been sent are terminated with SIGKILL.
+
+All the services that spawn processes must depend on this one so that they are
+stopped before 'kill' is called."
+ (with-monad %store-monad
+ (return (service
+ (documentation "When stopped, terminate all user processes.")
+ (provision '(user-processes))
+ (requirement '(root-file-system))
+ (start #~(const #t))
+ (stop #~(lambda _
+ ;; When this happens, all the processes have been
+ ;; killed, including 'deco', so DMD-OUTPUT-PORT and
+ ;; thus CURRENT-OUTPUT-PORT are dangling.
+ (call-with-output-file "/dev/console"
+ (lambda (port)
+ (display "sending all processes the TERM signal\n"
+ port)))
+
+ (kill -1 SIGTERM)
+ (sleep #$grace-delay)
+ (kill -1 SIGKILL)
+
+ (display "all processes have been terminated\n")
+ #f))
+ (respawn? #f)))))
+
(define (host-name-service name)
"Return a service that sets the host name to NAME."
(with-monad %store-monad
@@ -66,7 +144,7 @@
;; Since the login prompt shows the host name, wait for the 'host-name'
;; service to be done.
- (requirement '(host-name))
+ (requirement '(user-processes host-name))
(start #~(make-forkexec-constructor
(string-append #$mingetty "/sbin/mingetty")
@@ -87,6 +165,7 @@
(return (service
(documentation "Run libc's name service cache daemon (nscd).")
(provision '(nscd))
+ (requirement '(user-processes))
(start
#~(make-forkexec-constructor (string-append #$glibc "/sbin/nscd")
"-f" "/dev/null"
@@ -126,6 +205,7 @@
(service
(documentation "Run the syslog daemon (syslogd).")
(provision '(syslogd))
+ (requirement '(user-processes))
(start
#~(make-forkexec-constructor (string-append #$inetutils
"/libexec/syslogd")
@@ -161,6 +241,7 @@ BUILD-ACCOUNTS user accounts available under BUILD-USER-GID."
#:gid build-user-gid)))
(return (service
(provision '(guix-daemon))
+ (requirement '(user-processes))
(start
#~(make-forkexec-constructor (string-append #$guix
"/bin/guix-daemon")
@@ -189,6 +270,10 @@ This is the GNU operating system, welcome!\n\n")))
(nscd-service)
;; FIXME: Make this an activation-time thing instead of a service.
- (host-name-service "gnu"))))
+ (host-name-service "gnu")
+
+ ;; The "root" services.
+ (user-processes-service)
+ (root-file-system-service))))
;;; base.scm ends here
diff --git a/gnu/services/xorg.scm b/gnu/services/xorg.scm
index e47b33c9b8..db1d808715 100644
--- a/gnu/services/xorg.scm
+++ b/gnu/services/xorg.scm
@@ -161,7 +161,7 @@ reboot_cmd " dmd "/sbin/reboot
(service
(documentation "Xorg display server")
(provision '(xorg-server))
- (requirement '(host-name))
+ (requirement '(user-processes host-name))
(start
;; XXX: Work around the inability to specify env. vars. directly.
#~(make-forkexec-constructor