686 lines
28 KiB
Scheme
686 lines
28 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
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;;; Copyright © 2013-2016, 2018-2024 Ludovic Courtès <ludo@gnu.org>
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;;; Copyright © 2017 Clément Lassieur <clement@lassieur.org>
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;;; Copyright © 2018 Carlo Zancanaro <carlo@zancanaro.id.au>
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;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org>
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;;; Copyright © 2021 Maxime Devos <maximedevos@telenet.be>
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;;;
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;;; This file is part of GNU Guix.
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;;;
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;;; GNU Guix is free software; you can redistribute it and/or modify it
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;;; under the terms of the GNU General Public License as published by
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;;; the Free Software Foundation; either version 3 of the License, or (at
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;;; your option) any later version.
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;;;
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;;; GNU Guix is distributed in the hope that it will be useful, but
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;;; WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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;;; GNU General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
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(define-module (gnu services shepherd)
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#:use-module (guix ui)
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#:use-module (guix sets)
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#:use-module (guix gexp)
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#:use-module (guix store)
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#:use-module (guix records)
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#:use-module (guix packages)
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#:use-module (guix utils)
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#:use-module ((guix diagnostics)
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#:select (define-with-syntax-properties formatted-message))
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#:use-module (gnu services)
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#:use-module (gnu services herd)
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#:use-module (gnu packages admin)
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#:use-module (ice-9 match)
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#:use-module (ice-9 vlist)
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#:use-module (srfi srfi-1)
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#:use-module (srfi srfi-26)
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#:use-module (srfi srfi-34)
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#:use-module (srfi srfi-35)
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#:export (shepherd-configuration
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shepherd-configuration?
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shepherd-configuration-shepherd
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shepherd-configuration-services
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shepherd-root-service-type
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%shepherd-root-service
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shepherd-service-type
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shepherd-service
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shepherd-service?
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shepherd-service-documentation
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shepherd-service-provision
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shepherd-service-canonical-name
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shepherd-service-requirement
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shepherd-service-one-shot?
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shepherd-service-respawn-limit
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shepherd-service-respawn-delay
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shepherd-service-respawn?
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shepherd-service-start
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shepherd-service-stop
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shepherd-service-free-form
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shepherd-service-auto-start?
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shepherd-service-modules
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shepherd-action
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shepherd-action?
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shepherd-action-name
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shepherd-action-documentation
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shepherd-action-procedure
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shepherd-configuration-action
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%default-modules
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shepherd-service-file
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shepherd-service-lookup-procedure
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shepherd-service-back-edges
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shepherd-service-upgrade
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user-processes-service-type
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assert-valid-graph))
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;;; Commentary:
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;;;
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;;; Instantiating system services as a shepherd configuration file.
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;;;
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;;; Code:
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(define-record-type* <shepherd-configuration>
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shepherd-configuration make-shepherd-configuration
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shepherd-configuration?
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(shepherd shepherd-configuration-shepherd
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(default shepherd-0.10)) ; file-like
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(services shepherd-configuration-services
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(default '()))) ; list of <shepherd-service>
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(define (shepherd-boot-gexp config)
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"Return a gexp starting the shepherd service."
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(let ((shepherd (shepherd-configuration-shepherd config))
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(services (shepherd-configuration-services config)))
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#~(begin
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;; Keep track of the booted system.
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(false-if-exception (delete-file "/run/booted-system"))
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;; Make /run/booted-system, an indirect GC root, point to the store item
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;; /run/current-system points to. Use 'canonicalize-path' rather than
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;; 'readlink' to make sure we get the store item.
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(symlink (canonicalize-path "/run/current-system")
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"/run/booted-system")
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;; Ensure open file descriptors are close-on-exec so shepherd doesn't
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;; inherit them.
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(let loop ((fd 3))
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(when (< fd 1024)
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(false-if-exception
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(let ((flags (fcntl fd F_GETFD)))
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(when (zero? (logand flags FD_CLOEXEC))
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(fcntl fd F_SETFD (logior FD_CLOEXEC flags)))))
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(loop (+ fd 1))))
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;; Start shepherd.
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(execl #$(file-append shepherd "/bin/shepherd")
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"shepherd" "--config"
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#$(shepherd-configuration-file services shepherd)))))
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(define shepherd-packages
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(compose list shepherd-configuration-shepherd))
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(define shepherd-root-service-type
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(service-type
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(name 'shepherd-root)
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;; Extending the root shepherd service (aka. PID 1) happens by
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;; concatenating the list of services provided by the extensions.
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(compose concatenate)
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(extend (lambda (config extra-services)
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(shepherd-configuration
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(inherit config)
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(services (append (shepherd-configuration-services config)
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extra-services)))))
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(extensions (list (service-extension boot-service-type
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shepherd-boot-gexp)
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(service-extension profile-service-type
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shepherd-packages)))
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(default-value (shepherd-configuration))
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(description
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"Run the GNU Shepherd as PID 1---i.e., the operating system's first
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process. The Shepherd takes care of managing services such as daemons by
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ensuring they are started and stopped in the right order.")))
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(define %shepherd-root-service
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;; The root shepherd service, aka. PID 1. Its parameter is a
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;; <shepherd-configuration>.
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(service shepherd-root-service-type))
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(define-syntax shepherd-service-type
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(syntax-rules (description)
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"Return a <service-type> denoting a simple shepherd service--i.e., the type
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for a service that extends SHEPHERD-ROOT-SERVICE-TYPE and nothing else. When
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DEFAULT is given, use it as the service's default value."
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((_ service-name proc default (description text))
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(service-type
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(name service-name)
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(extensions
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(list (service-extension shepherd-root-service-type
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(compose list proc))))
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(default-value default)
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(description text)))
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((_ service-name proc (description text))
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(service-type
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(name service-name)
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(extensions
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(list (service-extension shepherd-root-service-type
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(compose list proc))))
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(description text)))))
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(define %default-imported-modules
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;; Default set of modules imported for a service's consumption.
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'((guix build utils)
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(guix build syscalls)))
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(define %default-modules
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;; Default set of modules visible in a service's file.
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`((shepherd service)
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((guix build utils) #:hide (delete))
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(guix build syscalls)))
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(define-with-syntax-properties (validate-provision (provision properties))
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(match provision
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(((? symbol?) ..1) provision)
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(_
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(raise
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(make-compound-condition
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(condition
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(&error-location
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(location (source-properties->location properties))))
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(formatted-message
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(G_ "'provision' must be a non-empty list of symbols")))))))
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(define-record-type* <shepherd-service>
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shepherd-service make-shepherd-service
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shepherd-service?
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(documentation shepherd-service-documentation ;string
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(default "[No documentation.]"))
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(provision shepherd-service-provision ;list of symbols
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(sanitize validate-provision))
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(requirement shepherd-service-requirement ;list of symbols
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(default '()))
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(one-shot? shepherd-service-one-shot? ;Boolean
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(default #f))
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(respawn? shepherd-service-respawn? ;Boolean
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(default #t))
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(respawn-limit shepherd-service-respawn-limit
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(default #f))
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(respawn-delay shepherd-service-respawn-delay
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(default #f))
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(free-form shepherd-service-free-form ;#f | g-expression (service)
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(default #f))
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(start shepherd-service-start ;g-expression (procedure)
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(default #~(const #t)))
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(stop shepherd-service-stop ;g-expression (procedure)
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(default #~(const #f)))
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(actions shepherd-service-actions ;list of <shepherd-action>
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(default '()))
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(auto-start? shepherd-service-auto-start? ;Boolean
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(default #t))
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(modules shepherd-service-modules ;list of module names
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(default %default-modules)))
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(define-record-type* <shepherd-action>
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shepherd-action make-shepherd-action
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shepherd-action?
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(name shepherd-action-name) ;symbol
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(procedure shepherd-action-procedure) ;gexp
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(documentation shepherd-action-documentation)) ;string
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(define (shepherd-service-canonical-name service)
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"Return the 'canonical name' of SERVICE."
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(first (shepherd-service-provision service)))
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(define (assert-valid-graph services)
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"Raise an error if SERVICES does not define a valid shepherd service graph,
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for instance if a service requires a nonexistent service, or if more than one
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service uses a given name.
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These are constraints that shepherd's 'register-service' verifies but we'd
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better verify them here statically than wait until PID 1 halts with an
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assertion failure."
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(define provisions
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;; The set of provisions (symbols). Bail out if a symbol is given more
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;; than once.
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(fold (lambda (service set)
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(define (assert-unique symbol)
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(when (set-contains? set symbol)
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(raise (condition
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(&message
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(message
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(format #f (G_ "service '~a' provided more than once")
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symbol)))))))
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(for-each assert-unique (shepherd-service-provision service))
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(fold set-insert set (shepherd-service-provision service)))
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(setq 'shepherd)
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services))
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(define (assert-satisfied-requirements service)
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;; Bail out if the requirements of SERVICE aren't satisfied.
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(for-each (lambda (requirement)
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(unless (set-contains? provisions requirement)
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(raise (condition
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(&message
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(message
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(format #f (G_ "service '~a' requires '~a', \
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which is not provided by any service")
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(match (shepherd-service-provision service)
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((head . _) head)
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(_ service))
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requirement)))))))
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(shepherd-service-requirement service)))
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(for-each assert-satisfied-requirements services))
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(define %store-characters
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;; Valid store characters; see 'checkStoreName' in the daemon.
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(string->char-set
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"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+-._?="))
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(define (shepherd-service-file-name service)
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"Return the file name where the initialization code for SERVICE is to be
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stored."
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(let ((provisions (string-join (map symbol->string
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(shepherd-service-provision service)))))
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(string-append "shepherd-"
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(string-map (lambda (chr)
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(if (char-set-contains? %store-characters chr)
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chr
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#\-))
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provisions)
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".scm")))
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(define (shepherd-service-file/regular service)
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"Return a file defining SERVICE, a service whose 'free-form' field is #f."
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(scheme-file (shepherd-service-file-name service)
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(with-imported-modules %default-imported-modules
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#~(begin
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(use-modules #$@(shepherd-service-modules service))
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(service
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'#$(shepherd-service-provision service)
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#:documentation '#$(shepherd-service-documentation service)
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#:requirement '#$(shepherd-service-requirement service)
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;; The 'one-shot?' slot is new in Shepherd 0.6.0.
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;; Older versions ignore it.
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#:one-shot? '#$(shepherd-service-one-shot? service)
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#:respawn? '#$(shepherd-service-respawn? service)
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#$@(if (shepherd-service-respawn-limit service)
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`(#:respawn-limit
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,(shepherd-service-respawn-limit service))
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'())
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#$@(if (shepherd-service-respawn-delay service)
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`(#:respawn-delay
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,(shepherd-service-respawn-delay service))
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'())
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#:start #$(shepherd-service-start service)
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#:stop #$(shepherd-service-stop service)
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#:actions
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(actions
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#$@(map (match-lambda
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(($ <shepherd-action> name proc doc)
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#~(#$name #$doc #$proc)))
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(shepherd-service-actions service))))))))
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(define (shepherd-service-file/free-form service)
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"Return a file defining SERVICE, a service whose 'free-form' field is set."
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(scheme-file (shepherd-service-file-name service)
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(with-imported-modules %default-imported-modules
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#~(begin
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(use-modules #$@(shepherd-service-modules service))
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#$(shepherd-service-free-form service)))))
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(define (shepherd-service-file service)
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"Return a file defining SERVICE."
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(if (shepherd-service-free-form service)
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(shepherd-service-file/free-form service)
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(shepherd-service-file/regular service)))
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(define (scm->go file shepherd)
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"Compile FILE, which contains code to be loaded by shepherd's config file,
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and return the resulting '.go' file. SHEPHERD is used as shepherd package."
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(define shepherd&co
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(cons shepherd
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(match (lookup-package-input shepherd "guile-fibers")
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(#f '())
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(fibers (list fibers)))))
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(let-system (system target)
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(with-extensions shepherd&co
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(computed-file (string-append (basename (scheme-file-name file) ".scm")
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".go")
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#~(begin
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(use-modules (system base compile)
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(system base target))
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;; Do the same as the Shepherd's 'load-in-user-module'.
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(let ((env (make-fresh-user-module)))
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(module-use! env (resolve-interface '(shepherd service)))
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(with-target #$(or target #~%host-type)
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(lambda _
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(compile-file #$file #:output-file #$output
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#:env env)))))
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;; It's faster to build locally than to download.
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#:options '(#:local-build? #t
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#:substitutable? #f)))))
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(define (shepherd-configuration-action file)
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"Return a 'configuration' action to display FILE, which should be the name
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of the service's configuration file."
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(shepherd-action
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(name 'configuration)
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(documentation "Display the name of this service's configuration file.")
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(procedure #~(lambda (_)
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(format #t "~a~%" #$file)
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#$file))))
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(define (shepherd-configuration-file services shepherd)
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"Return the shepherd configuration file for SERVICES. SHEPHERD is used
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as shepherd package."
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(assert-valid-graph services)
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(let ((files (map shepherd-service-file services))
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(scm->go (cute scm->go <> shepherd)))
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(define config
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#~(begin
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(use-modules (srfi srfi-1))
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(define (make-user-module)
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;; Copied from (shepherd support), where it's private.
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(let ((m (make-fresh-user-module)))
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(module-use! m (resolve-interface '(shepherd service)))
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m))
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;; There's code run from shepherd that uses 'call-with-input-file' &
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;; co.--e.g., the 'urandom-seed' service. Starting from Shepherd
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;; 0.9.2, users need to make sure not to leak non-close-on-exec file
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;; descriptors to child processes. To address that, replace the
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;; standard bindings with O_CLOEXEC variants.
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(set! call-with-input-file
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(lambda (file proc)
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(call-with-port (open file (logior O_RDONLY O_CLOEXEC))
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proc)))
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(set! call-with-output-file
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(lambda (file proc)
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(call-with-port (open file (logior O_WRONLY O_CREAT O_CLOEXEC))
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proc)))
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;; Specify the default environment visible to all the services.
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;; Without this statement, all the environment variables of PID 1
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;; are inherited by child services.
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(default-environment-variables
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'("PATH=/run/current-system/profile/bin"))
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;; Booting off a DVD, especially on a slow machine, can make
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;; everything slow. Thus, increase the timeout compared to the
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;; default 5s in the Shepherd 0.7.0. See
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;; <https://bugs.gnu.org/40572>.
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(default-pid-file-timeout 30)
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;; Load service files one by one; filter out those that could not be
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;; loaded--e.g., due to an unbound variable--such that an error in
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;; one service definition does not prevent the system from booting.
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(register-services
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(parameterize ((current-warning-port (%make-void-port "w")))
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(filter-map (lambda (file)
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(with-exception-handler
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(lambda (exception)
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(format #t "Exception caught \
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while loading '~a': ~s~%"
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file exception)
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#f)
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(lambda ()
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(save-module-excursion
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(lambda ()
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(set-current-module (make-user-module))
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(load-compiled file))))
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#:unwind? #t))
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'#$(map scm->go files))))
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(format #t "starting services...~%")
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(let ((services-to-start
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'#$(append-map shepherd-service-provision
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(filter shepherd-service-auto-start?
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services))))
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(start-in-the-background services-to-start)
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;; Hang up stdin. At this point, we assume that 'start' methods
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;; that required user interaction on the console (e.g.,
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;; 'cryptsetup open' invocations, post-fsck emergency REPL) have
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;; completed. User interaction becomes impossible after this
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;; call; this avoids situations where services wrongfully lead
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;; PID 1 to read from stdin (the console), which users may not
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;; have access to (see <https://bugs.gnu.org/23697>).
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(redirect-port (open "/dev/null" (logior O_RDONLY O_CLOEXEC))
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(current-input-port)))))
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(scheme-file "shepherd.conf" config)))
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(define* (shepherd-service-lookup-procedure services
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#:optional
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(provision
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shepherd-service-provision))
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"Return a procedure that, when passed a symbol, return the item among
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SERVICES that provides this symbol. PROVISION must be a one-argument
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procedure that takes a service and returns the list of symbols it provides."
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(let ((services (fold (lambda (service result)
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(fold (cut vhash-consq <> service <>)
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result
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(provision service)))
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vlist-null
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services)))
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(lambda (name)
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(match (vhash-assq name services)
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((_ . service) service)
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(#f #f)))))
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(define* (shepherd-service-back-edges services
|
||
#:key
|
||
(provision shepherd-service-provision)
|
||
(requirement shepherd-service-requirement))
|
||
"Return a procedure that, when given a <shepherd-service> from SERVICES,
|
||
returns the list of <shepherd-service> that depend on it.
|
||
|
||
Use PROVISION and REQUIREMENT as one-argument procedures that return the
|
||
symbols provided/required by a service."
|
||
(define provision->service
|
||
(shepherd-service-lookup-procedure services provision))
|
||
|
||
(define edges
|
||
(fold (lambda (service edges)
|
||
(fold (lambda (requirement edges)
|
||
(vhash-consq (provision->service requirement) service
|
||
edges))
|
||
edges
|
||
(requirement service)))
|
||
vlist-null
|
||
services))
|
||
|
||
(lambda (service)
|
||
(vhash-foldq* cons '() service edges)))
|
||
|
||
(define (shepherd-service-upgrade live target)
|
||
"Return two values: the subset of LIVE (a list of <live-service>) that needs
|
||
to be unloaded, and the subset of TARGET (a list of <shepherd-service>) that
|
||
need to be restarted to complete their upgrade."
|
||
(define (essential? service)
|
||
(memq (first (live-service-provision service))
|
||
'(root shepherd)))
|
||
|
||
(define lookup-target
|
||
(shepherd-service-lookup-procedure target
|
||
shepherd-service-provision))
|
||
|
||
(define lookup-live
|
||
(shepherd-service-lookup-procedure live
|
||
live-service-provision))
|
||
|
||
(define (running? service)
|
||
(and=> (lookup-live (shepherd-service-canonical-name service))
|
||
live-service-running))
|
||
|
||
(define live-service-dependents
|
||
(shepherd-service-back-edges live
|
||
#:provision live-service-provision
|
||
#:requirement live-service-requirement))
|
||
|
||
(define (obsolete? service)
|
||
(match (lookup-target (first (live-service-provision service)))
|
||
(#f (every obsolete? (live-service-dependents service)))
|
||
(_ #f)))
|
||
|
||
(define to-restart
|
||
;; Restart services that are currently running.
|
||
(filter running? target))
|
||
|
||
(define to-unload
|
||
;; Unload services that are no longer required. Essential services must
|
||
;; be kept and transient services such as inetd child services should be
|
||
;; kept as well--they'll vanish eventually.
|
||
(remove (lambda (live)
|
||
(or (essential? live)
|
||
(live-service-transient? live)))
|
||
(filter obsolete? live)))
|
||
|
||
(values to-unload to-restart))
|
||
|
||
|
||
;;;
|
||
;;; 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
|