diff options
Diffstat (limited to 'gnu/build')
| -rw-r--r-- | gnu/build/activation.scm | 49 | ||||
| -rw-r--r-- | gnu/build/linux-container.scm | 40 | ||||
| -rw-r--r-- | gnu/build/shepherd.scm | 177 |
3 files changed, 250 insertions, 16 deletions
diff --git a/gnu/build/activation.scm b/gnu/build/activation.scm index d36eeafe47..beee56d437 100644 --- a/gnu/build/activation.scm +++ b/gnu/build/activation.scm @@ -28,7 +28,7 @@ activate-user-home activate-etc activate-setuid-programs - activate-/bin/sh + activate-special-files activate-modprobe activate-firmware activate-ptrace-attach @@ -80,16 +80,27 @@ (member file '("." ".."))) (define* (copy-account-skeletons home - #:optional (directory %skeleton-directory)) - "Copy the account skeletons from DIRECTORY to HOME." + #:key + (directory %skeleton-directory) + uid gid) + "Copy the account skeletons from DIRECTORY to HOME. When UID is an integer, +make it the owner of all the files created; likewise for GID." + (define (set-owner file) + (when (or uid gid) + (chown file (or uid -1) (or gid -1)))) + (let ((files (scandir directory (negate dot-or-dot-dot?) string<?))) (mkdir-p home) + (set-owner home) (for-each (lambda (file) (let ((target (string-append home "/" file))) (copy-recursively (string-append directory "/" file) target #:log (%make-void-port "w")) + (for-each set-owner + (find-files target (const #t) + #:directories? #t)) (make-file-writable target))) files))) @@ -272,9 +283,14 @@ they already exist." ((name uid group supplementary-groups comment home create-home? shell password system?) (unless (or (not home) (directory-exists? home)) - (mkdir-p home) - (unless system? - (copy-account-skeletons home)))))) + (let* ((pw (getpwnam name)) + (uid (passwd:uid pw)) + (gid (passwd:gid pw))) + (mkdir-p home) + (chown home uid gid) + (unless system? + (copy-account-skeletons home + #:uid uid #:gid gid))))))) (for-each ensure-user-home users)) @@ -362,10 +378,23 @@ copy SOURCE to TARGET." (for-each make-setuid-program programs)) -(define (activate-/bin/sh shell) - "Change /bin/sh to point to SHELL." - (symlink shell "/bin/sh.new") - (rename-file "/bin/sh.new" "/bin/sh")) +(define (activate-special-files special-files) + "Install the files listed in SPECIAL-FILES. Each element of SPECIAL-FILES +is a pair where the first element is the name of the special file and the +second element is the name it should appear at, such as: + + ((\"/bin/sh\" \"/gnu/store/…-bash/bin/sh\") + (\"/usr/bin/env\" \"/gnu/store/…-coreutils/bin/env\")) +" + (define install-special-file + (match-lambda + ((target file) + (let ((pivot (string-append target ".new"))) + (mkdir-p (dirname target)) + (symlink file pivot) + (rename-file pivot target))))) + + (for-each install-special-file special-files)) (define (activate-modprobe modprobe) "Tell the kernel to use MODPROBE to load modules." diff --git a/gnu/build/linux-container.scm b/gnu/build/linux-container.scm index b71d6a5f88..95bfd92dde 100644 --- a/gnu/build/linux-container.scm +++ b/gnu/build/linux-container.scm @@ -1,5 +1,6 @@ ;;; GNU Guix --- Functional package management for GNU ;;; Copyright © 2015 David Thompson <davet@gnu.org> +;;; Copyright © 2017 Ludovic Courtès <ludo@gnu.org> ;;; ;;; This file is part of GNU Guix. ;;; @@ -32,7 +33,8 @@ %namespaces run-container call-with-container - container-excursion)) + container-excursion + container-excursion*)) (define (user-namespace-supported?) "Return #t if user namespaces are supported on this system." @@ -128,13 +130,19 @@ for the process." "/dev/fuse")) ;; Setup the container's /dev/console by bind mounting the pseudo-terminal - ;; associated with standard input. - (let ((in (current-input-port)) - (console (scope "/dev/console"))) - (when (isatty? in) + ;; associated with standard input when there is one. + (let* ((in (current-input-port)) + (tty (catch 'system-error + (lambda () + ;; This call throws if IN does not correspond to a tty. + ;; This is more reliable than 'isatty?'. + (ttyname in)) + (const #f))) + (console (scope "/dev/console"))) + (when tty (touch console) (chmod console #o600) - (bind-mount (ttyname in) console))) + (bind-mount tty console))) ;; Setup standard input/output/error. (symlink "/proc/self/fd" (scope "/dev/fd")) @@ -229,6 +237,8 @@ host user identifiers to map into the user namespace." namespaces))) (lambda args ;; Forward the exception to the parent process. + ;; FIXME: SRFI-35 conditions and non-trivial objects + ;; cannot be 'read' so they shouldn't be written as is. (write args child) (primitive-exit 3)))) ;; TODO: Manage capabilities. @@ -318,3 +328,21 @@ return the exit status." (match (waitpid pid) ((_ . status) (status:exit-val status)))))) + +(define (container-excursion* pid thunk) + "Like 'container-excursion', but return the return value of THUNK." + (match (pipe) + ((in . out) + (match (container-excursion pid + (lambda () + (close-port in) + (write (thunk) out))) + (0 + (close-port out) + (let ((result (read in))) + (close-port in) + result)) + (_ ;maybe PID died already + (close-port out) + (close-port in) + #f))))) diff --git a/gnu/build/shepherd.scm b/gnu/build/shepherd.scm new file mode 100644 index 0000000000..8fc74bc482 --- /dev/null +++ b/gnu/build/shepherd.scm @@ -0,0 +1,177 @@ +;;; GNU Guix --- Functional package management for GNU +;;; Copyright © 2017 Ludovic Courtès <ludo@gnu.org> +;;; +;;; 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 (ice-9 match) + #:export (make-forkexec-constructor/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") + (title 'device) + (mount-point directory) + (type "tmpfs") + (check? #f))) + + (define passwd + ;; This is for processes in the default user namespace but living in a + ;; different mount namespace, so that they can lookup users. + (file-system-mapping + (source "/etc/passwd") (target source))) + + (define nscd-socket + (file-system-mapping + (source "/var/run/nscd") (target source) + (writable? #t))) + + (append (cons (tmpfs "/tmp") %container-file-systems) + (let ((mappings `(,@(if (memq 'net namespaces) + '() + (cons nscd-socket + %network-file-mappings)) + ,@(if (and (memq 'mnt namespaces) + (not (memq 'user namespaces))) + (list passwd) + '()) + ,%store-mapping))) ;XXX: coarse-grain + (map file-system-mapping->bind-mount + (filter (lambda (mapping) + (file-exists? (file-system-mapping-source mapping))) + mappings))))) + +;; XXX: Lazy-bind the Shepherd to avoid a compile-time dependency. +(module-autoload! (current-module) + '(shepherd service) '(read-pid-file exec-command)) + +(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 () + (read-pid-file pid-file + #:max-delay max-delay))) + (#f + (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* (make-forkexec-constructor/container command + #:key + (namespaces + (default-namespaces args)) + (mappings '()) + (user #f) + (group #f) + (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) + (call-with-output-file log-file (const #t)))) + + (let ((pid (run-container container-directory + mounts namespaces 1 + (lambda () + (mkdir-p "/var/run") + (clean-up pid-file) + (clean-up log-file) + + (exec-command command + #:user user + #:group group + #: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)))) + +;; Local Variables: +;; eval: (put 'container-excursion* 'scheme-indent-function 1) +;; End: + +;;; shepherd.scm ends here |