Browse Source
Add (guix build syscalls).
Add (guix build syscalls).
* guix/build/syscalls.scm, tests/syscalls.scm: New files. * Makefile.am (MODULES): Add guix/build/syscalls.scm. (SCM_TESTS): Add tests/syscalls.scm. * guix/utils.scm (%libc-errno-pointer, errno): Remove; take from (guix build syscalls).version-0.8.3
Ludovic Courtès
8 years ago
4 changed files with 207 additions and 33 deletions
@ -0,0 +1,156 @@ |
|||
;;; GNU Guix --- Functional package management for GNU |
|||
;;; Copyright © 2014 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 (guix build syscalls) |
|||
#:use-module (system foreign) |
|||
#:use-module (rnrs bytevectors) |
|||
#:use-module (srfi srfi-1) |
|||
#:use-module (ice-9 rdelim) |
|||
#:use-module (ice-9 match) |
|||
#:export (errno |
|||
MS_RDONLY |
|||
MS_REMOUNT |
|||
MS_BIND |
|||
MS_MOVE |
|||
mount |
|||
umount)) |
|||
|
|||
;;; Commentary: |
|||
;;; |
|||
;;; This module provides bindings to libc's syscall wrappers. It uses the |
|||
;;; FFI, and thus requires a dynamically-linked Guile. (For statically-linked |
|||
;;; Guile, we instead apply 'guile-linux-syscalls.patch'.) |
|||
;;; |
|||
;;; Code: |
|||
|
|||
(define %libc-errno-pointer |
|||
;; Glibc's 'errno' pointer. |
|||
(let ((errno-loc (dynamic-func "__errno_location" (dynamic-link)))) |
|||
(and errno-loc |
|||
(let ((proc (pointer->procedure '* errno-loc '()))) |
|||
(proc))))) |
|||
|
|||
(define errno |
|||
(if %libc-errno-pointer |
|||
(let ((bv (pointer->bytevector %libc-errno-pointer (sizeof int)))) |
|||
(lambda () |
|||
"Return the current errno." |
|||
;; XXX: We assume that nothing changes 'errno' while we're doing all this. |
|||
;; In particular, that means that no async must be running here. |
|||
|
|||
;; Use one of the fixed-size native-ref procedures because they are |
|||
;; optimized down to a single VM instruction, which reduces the risk |
|||
;; that we fiddle with 'errno' (needed on Guile 2.0.5, libc 2.11.) |
|||
(let-syntax ((ref (lambda (s) |
|||
(syntax-case s () |
|||
((_ bv) |
|||
(case (sizeof int) |
|||
((4) |
|||
#'(bytevector-s32-native-ref bv 0)) |
|||
((8) |
|||
#'(bytevector-s64-native-ref bv 0)) |
|||
(else |
|||
(error "unsupported 'int' size" |
|||
(sizeof int))))))))) |
|||
(ref bv)))) |
|||
(lambda () 0))) |
|||
|
|||
(define (augment-mtab source target type options) |
|||
"Augment /etc/mtab with information about the given mount point." |
|||
(let ((port (open-file "/etc/mtab" "a"))) |
|||
(format port "~a ~a ~a ~a 0 0~%" |
|||
source target type (or options "rw")) |
|||
(close-port port))) |
|||
|
|||
(define (read-mtab port) |
|||
"Read an mtab-formatted file from PORT, returning a list of tuples." |
|||
(let loop ((result '())) |
|||
(let ((line (read-line port))) |
|||
(if (eof-object? line) |
|||
(reverse result) |
|||
(loop (cons (string-tokenize line) result)))))) |
|||
|
|||
(define (remove-from-mtab target) |
|||
"Remove mount point TARGET from /etc/mtab." |
|||
(define entries |
|||
(remove (match-lambda |
|||
((device mount-point type options freq passno) |
|||
(string=? target mount-point)) |
|||
(_ #f)) |
|||
(call-with-input-file "/etc/fstab" read-mtab))) |
|||
|
|||
(call-with-output-file "/etc/fstab" |
|||
(lambda (port) |
|||
(for-each (match-lambda |
|||
((device mount-point type options freq passno) |
|||
(format port "~a ~a ~a ~a ~a ~a~%" |
|||
device mount-point type options freq passno))) |
|||
entries)))) |
|||
|
|||
;; Linux mount flags, from libc's <sys/mount.h>. |
|||
(define MS_RDONLY 1) |
|||
(define MS_REMOUNT 32) |
|||
(define MS_BIND 4096) |
|||
(define MS_MOVE 8192) |
|||
|
|||
(define mount |
|||
(let* ((ptr (dynamic-func "mount" (dynamic-link))) |
|||
(proc (pointer->procedure int ptr `(* * * ,unsigned-long *)))) |
|||
(lambda* (source target type #:optional (flags 0) options |
|||
#:key (update-mtab? #t)) |
|||
"Mount device SOURCE on TARGET as a file system TYPE. Optionally, FLAGS |
|||
may be a bitwise-or of the MS_* <sys/mount.h> constants, and OPTIONS may be a |
|||
string. When FLAGS contains MS_REMOUNT, SOURCE and TYPE are ignored. When |
|||
UPDATE-MTAB? is true, update /etc/mtab. Raise a 'system-error' exception on |
|||
error." |
|||
(let ((ret (proc (if source |
|||
(string->pointer source) |
|||
%null-pointer) |
|||
(string->pointer target) |
|||
(if type |
|||
(string->pointer type) |
|||
%null-pointer) |
|||
flags |
|||
(if options |
|||
(string->pointer options) |
|||
%null-pointer))) |
|||
(err (errno))) |
|||
(unless (zero? ret) |
|||
(throw 'system-error "mount" "mount ~S on ~S: ~A" |
|||
(list source target (strerror err)) |
|||
(list err))) |
|||
(when update-mtab? |
|||
(augment-mtab source target type options)))))) |
|||
|
|||
(define umount |
|||
(let* ((ptr (dynamic-func "umount2" (dynamic-link))) |
|||
(proc (pointer->procedure int ptr `(* ,int)))) |
|||
(lambda* (target #:optional (flags 0) |
|||
#:key (update-mtab? #t)) |
|||
"Unmount TARGET. Optionally FLAGS may be one of the MNT_* or UMOUNT_* |
|||
constants from <sys/mount.h>." |
|||
(let ((ret (proc (string->pointer target) flags)) |
|||
(err (errno))) |
|||
(unless (zero? ret) |
|||
(throw 'system-error "umount" "~S: ~A" |
|||
(list target (strerror err)) |
|||
(list err))) |
|||
(when update-mtab? |
|||
(remove-from-mtab target)))))) |
|||
|
|||
;;; syscalls.scm ends here |
|||
@ -0,0 +1,47 @@ |
|||
;;; GNU Guix --- Functional package management for GNU |
|||
;;; Copyright © 2014 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 (test-syscalls) |
|||
#:use-module (guix build syscalls) |
|||
#:use-module (srfi srfi-64)) |
|||
|
|||
;; Test the (guix build syscalls) module, although there's not much that can |
|||
;; actually be tested without being root. |
|||
|
|||
(test-begin "syscalls") |
|||
|
|||
(test-equal "mount, ENOENT" |
|||
ENOENT |
|||
(catch 'system-error |
|||
(lambda () |
|||
(mount "/dev/null" "/does-not-exist" "ext2") |
|||
#f) |
|||
(compose system-error-errno list))) |
|||
|
|||
(test-equal "umount, ENOENT" |
|||
ENOENT |
|||
(catch 'system-error |
|||
(lambda () |
|||
(umount "/does-not-exist") |
|||
#f) |
|||
(compose system-error-errno list))) |
|||
|
|||
(test-end) |
|||
|
|||
|
|||
(exit (= (test-runner-fail-count (test-runner-current)) 0)) |
|||
Write
Preview
Loading…
Cancel
Save
Reference in new issue