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authorMaxim Cournoyer <maxim.cournoyer@gmail.com>2022-10-25 23:17:09 -0400
committerMaxim Cournoyer <maxim.cournoyer@gmail.com>2022-11-15 14:15:11 -0500
commit0bb872b379a98e4523c8f8d946e581bad1c4c323 (patch)
treedb16253ba15de01de4af59a350eab52b45ededa3 /gnu/build
parent893482701490036f48832f7d187b6e259b6abdcf (diff)
install: Validate symlink target in evaluate-populate-directive.
* gnu/build/install.scm (evaluate-populate-directive): By default, error when the target of a symlink doesn't exist. Always ensure TARGET ends with "/". (populate-root-file-system): Call evaluate-populate-directive with #:error-on-dangling-symlink #t and add comment.
Diffstat (limited to 'gnu/build')
-rw-r--r--gnu/build/install.scm60
1 files changed, 40 insertions, 20 deletions
diff --git a/gnu/build/install.scm b/gnu/build/install.scm
index f5c8407b89..33a9616c0d 100644
--- a/gnu/build/install.scm
+++ b/gnu/build/install.scm
@@ -1,6 +1,7 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2016 Chris Marusich <cmmarusich@gmail.com>
+;;; Copyright © 2022 Maxim Cournoyer <maxim.cournoyer@gmail.com>
;;;
;;; This file is part of GNU Guix.
;;;
@@ -56,19 +57,24 @@ that the fonts, background images, etc. referred to by BOOTCFG are not GC'd."
(define* (evaluate-populate-directive directive target
#:key
(default-gid 0)
- (default-uid 0))
+ (default-uid 0)
+ (error-on-dangling-symlink? #t))
"Evaluate DIRECTIVE, an sexp describing a file or directory to create under
directory TARGET. DEFAULT-UID and DEFAULT-GID are the default UID and GID in
the context of the caller. If the directive matches those defaults then,
-'chown' won't be run."
+'chown' won't be run. When ERROR-ON-DANGLING-SYMLINK? is true, abort with an
+error when a dangling symlink would be created."
+ (define target* (if (string-suffix? "/" target)
+ target
+ (string-append target "/")))
(let loop ((directive directive))
(catch 'system-error
(lambda ()
(match directive
(('directory name)
- (mkdir-p (string-append target name)))
+ (mkdir-p (string-append target* name)))
(('directory name uid gid)
- (let ((dir (string-append target name)))
+ (let ((dir (string-append target* name)))
(mkdir-p dir)
;; If called from a context without "root" permissions, "chown"
;; to root will fail. In that case, do not try to run "chown"
@@ -78,27 +84,38 @@ the context of the caller. If the directive matches those defaults then,
(chown dir uid gid))))
(('directory name uid gid mode)
(loop `(directory ,name ,uid ,gid))
- (chmod (string-append target name) mode))
+ (chmod (string-append target* name) mode))
(('file name)
- (call-with-output-file (string-append target name)
+ (call-with-output-file (string-append target* name)
(const #t)))
(('file name (? string? content))
- (call-with-output-file (string-append target name)
+ (call-with-output-file (string-append target* name)
(lambda (port)
(display content port))))
((new '-> old)
- (let try ()
- (catch 'system-error
- (lambda ()
- (symlink old (string-append target new)))
- (lambda args
- ;; When doing 'guix system init' on the current '/', some
- ;; symlinks may already exists. Override them.
- (if (= EEXIST (system-error-errno args))
- (begin
- (delete-file (string-append target new))
- (try))
- (apply throw args))))))))
+ (let ((new* (string-append target* new)))
+ (let try ()
+ (catch 'system-error
+ (lambda ()
+ (when error-on-dangling-symlink?
+ ;; When the symbolic link points to a relative path,
+ ;; checking if its target exists must be done relatively
+ ;; to the link location.
+ (unless (if (string-prefix? "/" old)
+ (file-exists? old)
+ (with-directory-excursion (dirname new*)
+ (file-exists? old)))
+ (error (format #f "symlink `~a' points to nonexistent \
+file `~a'" new* old))))
+ (symlink old new*))
+ (lambda args
+ ;; When doing 'guix system init' on the current '/', some
+ ;; symlinks may already exists. Override them.
+ (if (= EEXIST (system-error-errno args))
+ (begin
+ (delete-file new*)
+ (try))
+ (apply throw args)))))))))
(lambda args
;; Usually we can only get here when installing to an existing root,
;; as with 'guix system init foo.scm /'.
@@ -142,7 +159,10 @@ STORE."
includes /etc, /var, /run, /bin/sh, etc., and all the symlinks to SYSTEM.
EXTRAS is a list of directives appended to the built-in directives to populate
TARGET."
- (for-each (cut evaluate-populate-directive <> target)
+ ;; It's expected that some symbolic link targets do not exist yet, so do not
+ ;; error on dangling links.
+ (for-each (cut evaluate-populate-directive <> target
+ #:error-on-dangling-symlink? #f)
(append (directives (%store-directory)) extras))
;; Add system generation 1.