;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2012, 2013, 2014, 2015, 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org>
;;; Copyright © 2013 Andreas Enge <andreas@enge.fr>
;;; Copyright © 2013 Nikita Karetnikov <nikita@karetnikov.org>
;;; Copyright © 2015, 2018 Mark H Weaver <mhw@netris.org>
;;; Copyright © 2018 Arun Isaac <arunisaac@systemreboot.net>
;;; Copyright © 2018, 2019 Ricardo Wurmus <rekado@elephly.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 (guix build service-utils)
  #:use-module (ice-9 match)
  #:use-module (guix build utils)
  #:export (mkdir-p/perms))

;; Based upon mkdir-p from (guix build utils)
(define (verify-not-symbolic dir)
  "Verify DIR or its ancestors aren't symbolic links."
  (define absolute?
    (string-prefix? "/" dir))

  (define not-slash
    (char-set-complement (char-set #\/)))

  (define (verify-component path)
    (when (eq? 'symlink (stat:type (lstat path)))
      (throw 'XXX-TODO-does-someone-have-an-idea? path)))

  (let loop ((components (string-tokenize dir not-slash))
             (root       (if absolute?
                             ""
                             ".")))
    (match components
      ((head tail ...)
       (let ((path (string-append root "/" head)))
         (catch 'system-error
           (lambda ()
             (verify-component path)
             (loop tail path))
           (lambda args
             (if (= ENOENT (system-error-errno args))
                 #t
                 (apply throw args))))))
      (() #t))))

(define (mkdir-p/perms directory owner bits)
  "Create the directory DIRECTORY and all its ancestors.
Verify no component of DIRECTORY is a symbolic link.
Warning: this is currently suspect to a TOCTOU race!"
  (verify-not-symbolic directory)
  (mkdir-p directory)
  (chown directory (passwd:uid owner) (passwd:gid owner))
  (chmod directory bits))