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-rw-r--r--gnu/system/file-systems.scm94
1 files changed, 87 insertions, 7 deletions
diff --git a/gnu/system/file-systems.scm b/gnu/system/file-systems.scm
index 4cc1221eb8..7011a279d3 100644
--- a/gnu/system/file-systems.scm
+++ b/gnu/system/file-systems.scm
@@ -1,5 +1,5 @@
;;; GNU Guix --- Functional package management for GNU
-;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2013, 2014, 2015, 2016, 2017 Ludovic Courtès <ludo@gnu.org>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -18,8 +18,8 @@
(define-module (gnu system file-systems)
#:use-module (ice-9 match)
+ #:use-module (srfi srfi-1)
#:use-module (guix records)
- #:use-module (guix store)
#:use-module ((gnu build file-systems)
#:select (string->uuid uuid->string))
#:re-export (string->uuid
@@ -63,7 +63,11 @@
file-system-mapping-target
file-system-mapping-writable?
- %store-mapping))
+ file-system-mapping->bind-mount
+
+ %store-mapping
+ %network-configuration-files
+ %network-file-mappings))
;;; Commentary:
;;;
@@ -95,11 +99,53 @@
(dependencies file-system-dependencies ; list of <file-system>
(default '()))) ; or <mapped-device>
-(define-inlinable (file-system-needed-for-boot? fs)
- "Return true if FS has the 'needed-for-boot?' flag set, or if it's the root
-file system."
+;; Note: This module is used both on the build side and on the host side.
+;; Arrange not to pull (guix store) and (guix config) because the latter
+;; differs from user to user.
+(define (%store-prefix)
+ "Return the store prefix."
+ (cond ((resolve-module '(guix store) #:ensure #f)
+ =>
+ (lambda (store)
+ ((module-ref store '%store-prefix))))
+ ((getenv "NIX_STORE")
+ => identity)
+ (else
+ "/gnu/store")))
+
+(define %not-slash
+ (char-set-complement (char-set #\/)))
+
+(define (file-prefix? file1 file2)
+ "Return #t if FILE1 denotes the name of a file that is a parent of FILE2,
+where both FILE1 and FILE2 are absolute file name. For example:
+
+ (file-prefix? \"/gnu\" \"/gnu/store\")
+ => #t
+
+ (file-prefix? \"/gn\" \"/gnu/store\")
+ => #f
+"
+ (and (string-prefix? "/" file1)
+ (string-prefix? "/" file2)
+ (let loop ((file1 (string-tokenize file1 %not-slash))
+ (file2 (string-tokenize file2 %not-slash)))
+ (match file1
+ (()
+ #t)
+ ((head1 tail1 ...)
+ (match file2
+ ((head2 tail2 ...)
+ (and (string=? head1 head2) (loop tail1 tail2)))
+ (()
+ #f)))))))
+
+(define (file-system-needed-for-boot? fs)
+ "Return true if FS has the 'needed-for-boot?' flag set, or if it holds the
+store--e.g., if FS is the root file system."
(or (%file-system-needed-for-boot? fs)
- (string=? "/" (file-system-mount-point fs))))
+ (and (file-prefix? (file-system-mount-point fs) (%store-prefix))
+ (not (memq 'bind-mount (file-system-flags fs))))))
(define (file-system->spec fs)
"Return a list corresponding to file-system FS that can be passed to the
@@ -324,6 +370,21 @@ TARGET in the other system."
(writable? file-system-mapping-writable? ;Boolean
(default #f)))
+(define (file-system-mapping->bind-mount mapping)
+ "Return a file system that realizes MAPPING, a <file-system-mapping>, using
+a bind mount."
+ (match mapping
+ (($ <file-system-mapping> source target writable?)
+ (file-system
+ (mount-point target)
+ (device source)
+ (type "none")
+ (flags (if writable?
+ '(bind-mount)
+ '(bind-mount read-only)))
+ (check? #f)
+ (create-mount-point? #t)))))
+
(define %store-mapping
;; Mapping of the host's store into the guest.
(file-system-mapping
@@ -331,4 +392,23 @@ TARGET in the other system."
(target (%store-prefix))
(writable? #f)))
+(define %network-configuration-files
+ ;; List of essential network configuration files.
+ '("/etc/resolv.conf"
+ "/etc/nsswitch.conf"
+ "/etc/services"
+ "/etc/hosts"))
+
+(define %network-file-mappings
+ ;; List of file mappings for essential network files.
+ (filter-map (lambda (file)
+ (file-system-mapping
+ (source file)
+ (target file)
+ ;; XXX: On some GNU/Linux systems, /etc/resolv.conf is a
+ ;; symlink to a file in a tmpfs which, for an unknown reason,
+ ;; cannot be bind mounted read-only within the container.
+ (writable? (string=? file "/etc/resolv.conf"))))
+ %network-configuration-files))
+
;;; file-systems.scm ends here