mirror of
https://git.in.rschanz.org/ryan77627/guix.git
synced 2024-11-12 09:56:14 -05:00
3e866e24f0
* gnu/build/shepherd.scm (make-forkexec-constructor/container): Set #o640 permissions for log file.
258 lines
10 KiB
Scheme
258 lines
10 KiB
Scheme
;;; GNU Guix --- Functional package management for GNU
|
|
;;; Copyright © 2017, 2018, 2019, 2020, 2022 Ludovic Courtès <ludo@gnu.org>
|
|
;;; Copyright © 2020 Mathieu Othacehe <othacehe@gnu.org>
|
|
;;; Copyright © 2022 Leo Nikkilä <hello@lnikki.la>
|
|
;;; Copyright © 2022 Arun Isaac <arunisaac@systemreboot.net>
|
|
;;;
|
|
;;; This file is part of GNU Guix.
|
|
;;;
|
|
;;; GNU Guix is free software; you can redistribute it and/or modify it
|
|
;;; under the terms of the GNU General Public License as published by
|
|
;;; the Free Software Foundation; either version 3 of the License, or (at
|
|
;;; your option) any later version.
|
|
;;;
|
|
;;; GNU Guix is distributed in the hope that it will be useful, but
|
|
;;; WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
;;; GNU General Public License for more details.
|
|
;;;
|
|
;;; You should have received a copy of the GNU General Public License
|
|
;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
|
|
|
|
(define-module (gnu build shepherd)
|
|
#:use-module (gnu system file-systems)
|
|
#:use-module (gnu build linux-container)
|
|
#:use-module (guix build utils)
|
|
#:use-module (srfi srfi-1)
|
|
#:use-module (srfi srfi-26)
|
|
#:use-module (ice-9 match)
|
|
;; XXX: Lazy-bind the Shepherd to avoid a compile-time dependency.
|
|
#:autoload (shepherd service) (fork+exec-command
|
|
read-pid-file
|
|
exec-command
|
|
%precious-signals)
|
|
#:autoload (shepherd system) (unblock-signals)
|
|
#:export (default-mounts
|
|
make-forkexec-constructor/container
|
|
fork+exec-command/container))
|
|
|
|
;;; Commentary:
|
|
;;;
|
|
;;; This module provides extensions to the GNU Shepherd. In particular, it
|
|
;;; provides a helper to start services in a container.
|
|
;;;
|
|
;;; Code:
|
|
|
|
(define (clean-up file)
|
|
(when file
|
|
(catch 'system-error
|
|
(lambda ()
|
|
(delete-file file))
|
|
(lambda args
|
|
(unless (= ENOENT (system-error-errno args))
|
|
(apply throw args))))))
|
|
|
|
(define-syntax-rule (catch-system-error exp)
|
|
(catch 'system-error
|
|
(lambda ()
|
|
exp)
|
|
(const #f)))
|
|
|
|
(define (default-namespaces args)
|
|
;; Most daemons are here to talk to the network, and most of them expect to
|
|
;; run under a non-zero UID.
|
|
(fold delq %namespaces '(net user)))
|
|
|
|
(define* (default-mounts #:key (namespaces (default-namespaces '())))
|
|
(define (tmpfs directory)
|
|
(file-system
|
|
(device "none")
|
|
(mount-point directory)
|
|
(type "tmpfs")
|
|
(check? #f)))
|
|
|
|
(define accounts
|
|
;; This is for processes in the default user namespace but living in a
|
|
;; different mount namespace, so that they can lookup users.
|
|
(list (file-system-mapping
|
|
(source "/etc/passwd") (target source))
|
|
(file-system-mapping
|
|
(source "/etc/group") (target source))))
|
|
|
|
(append (cons (tmpfs "/tmp") %container-file-systems)
|
|
(let ((mappings `(,@(if (memq 'net namespaces)
|
|
'()
|
|
%network-file-mappings)
|
|
,@(if (and (memq 'mnt namespaces)
|
|
(not (memq 'user namespaces)))
|
|
accounts
|
|
'())
|
|
|
|
;; Tell the process what timezone we're in. This
|
|
;; makes sure that, for instance, its syslog
|
|
;; messages have the correct timestamp.
|
|
,(file-system-mapping
|
|
(source "/etc/localtime")
|
|
(target source))
|
|
|
|
,%store-mapping))) ;XXX: coarse-grain
|
|
(map file-system-mapping->bind-mount
|
|
(filter (lambda (mapping)
|
|
(file-exists? (file-system-mapping-source mapping)))
|
|
mappings)))))
|
|
|
|
(define* (read-pid-file/container pid pid-file #:key (max-delay 5))
|
|
"Read PID-FILE in the container namespaces of PID, which exists in a
|
|
separate mount and PID name space. Return the \"outer\" PID. "
|
|
(match (container-excursion* pid
|
|
(lambda ()
|
|
;; XXX: Trick for Shepherd 0.9: prevent 'read-pid-file' from
|
|
;; using (@ (fibers) sleep), which would try to suspend the
|
|
;; current task, which doesn't work in this extra process.
|
|
(with-continuation-barrier
|
|
(lambda ()
|
|
(read-pid-file pid-file
|
|
#:max-delay max-delay)))))
|
|
(#f
|
|
;; Send SIGTERM to the whole process group.
|
|
(catch-system-error (kill (- pid) SIGTERM))
|
|
#f)
|
|
((? integer? container-pid)
|
|
;; XXX: When COMMAND is started in a separate PID namespace, its
|
|
;; PID is always 1, but that's not what Shepherd needs to know.
|
|
pid)))
|
|
|
|
(define* (exec-command* command #:key user group log-file pid-file
|
|
(supplementary-groups '())
|
|
(directory "/") (environment-variables (environ)))
|
|
"Like 'exec-command', but first restore signal handles modified by
|
|
shepherd (PID 1)."
|
|
;; First restore the default handlers.
|
|
(for-each (cut sigaction <> SIG_DFL) %precious-signals)
|
|
|
|
;; Unblock any signals that have been blocked by the parent process.
|
|
(unblock-signals %precious-signals)
|
|
|
|
(mkdir-p "/var/run")
|
|
(clean-up pid-file)
|
|
|
|
(exec-command command
|
|
#:user user
|
|
#:group group
|
|
#:supplementary-groups supplementary-groups
|
|
#:log-file log-file
|
|
#:directory directory
|
|
#:environment-variables environment-variables))
|
|
|
|
(define* (make-forkexec-constructor/container command
|
|
#:key
|
|
(namespaces
|
|
(default-namespaces args))
|
|
(mappings '())
|
|
(user #f)
|
|
(group #f)
|
|
(supplementary-groups '())
|
|
(log-file #f)
|
|
pid-file
|
|
(pid-file-timeout 5)
|
|
(directory "/")
|
|
(environment-variables
|
|
(environ))
|
|
#:rest args)
|
|
"This is a variant of 'make-forkexec-constructor' that starts COMMAND in
|
|
NAMESPACES, a list of Linux namespaces such as '(mnt ipc). MAPPINGS is the
|
|
list of <file-system-mapping> to make in the case of a separate mount
|
|
namespace, in addition to essential bind-mounts such /proc."
|
|
(define container-directory
|
|
(match command
|
|
((program _ ...)
|
|
(string-append "/var/run/containers/" (basename program)))))
|
|
|
|
(define auto-mappings
|
|
`(,@(if log-file
|
|
(list (file-system-mapping
|
|
(source log-file)
|
|
(target source)
|
|
(writable? #t)))
|
|
'())))
|
|
|
|
(define mounts
|
|
(append (map file-system-mapping->bind-mount
|
|
(append auto-mappings mappings))
|
|
(default-mounts #:namespaces namespaces)))
|
|
|
|
(lambda args
|
|
(mkdir-p container-directory)
|
|
|
|
(when log-file
|
|
;; Create LOG-FILE so we can map it in the container.
|
|
(unless (file-exists? log-file)
|
|
(close (open log-file (logior O_CREAT O_APPEND O_CLOEXEC) #o640))
|
|
(when user
|
|
(let ((pw (getpwnam user)))
|
|
(chown log-file (passwd:uid pw) (passwd:gid pw))))))
|
|
|
|
(let ((pid (run-container container-directory
|
|
mounts namespaces 1
|
|
(lambda ()
|
|
(exec-command* command
|
|
#:user user
|
|
#:group group
|
|
#:supplementary-groups
|
|
supplementary-groups
|
|
#:pid-file pid-file
|
|
#:log-file log-file
|
|
#:directory directory
|
|
#:environment-variables
|
|
environment-variables)))))
|
|
(if pid-file
|
|
(if (or (memq 'mnt namespaces) (memq 'pid namespaces))
|
|
(read-pid-file/container pid pid-file
|
|
#:max-delay pid-file-timeout)
|
|
(read-pid-file pid-file #:max-delay pid-file-timeout))
|
|
pid))))
|
|
|
|
(define* (fork+exec-command/container command
|
|
#:key pid
|
|
#:allow-other-keys
|
|
#:rest args)
|
|
"This is a variant of 'fork+exec-command' procedure, that joins the
|
|
namespaces of process PID beforehand. If there is no support for containers,
|
|
on Hurd systems for instance, fallback to direct forking."
|
|
(define (strip-pid args)
|
|
;; TODO: Replace with 'strip-keyword-arguments' when that no longer pulls
|
|
;; in (guix config).
|
|
(let loop ((args args)
|
|
(result '()))
|
|
(match args
|
|
(()
|
|
(reverse result))
|
|
((#:pid _ . rest)
|
|
(loop rest result))
|
|
((head . rest)
|
|
(loop rest (cons head result))))))
|
|
|
|
(let ((container-support? (file-exists? "/proc/self/ns")))
|
|
(if (and container-support?
|
|
(not (and pid (= pid (getpid)))))
|
|
(container-excursion* pid
|
|
(lambda ()
|
|
;; Note: In the Shepherd 0.9, 'fork+exec-command' expects to be
|
|
;; called from the shepherd process (because it creates a pipe to
|
|
;; capture stdout/stderr and spawns a logging fiber) so we cannot
|
|
;; use it here.
|
|
(match (primitive-fork)
|
|
(0 (dynamic-wind
|
|
(const #t)
|
|
(lambda ()
|
|
(apply exec-command* command (strip-pid args)))
|
|
(lambda ()
|
|
(primitive-_exit 127))))
|
|
(pid pid)))) ;XXX: assuming the same PID namespace
|
|
(apply fork+exec-command command (strip-pid args)))))
|
|
|
|
;; Local Variables:
|
|
;; eval: (put 'container-excursion* 'scheme-indent-function 1)
|
|
;; End:
|
|
|
|
;;; shepherd.scm ends here
|