diff options
Diffstat (limited to 'guix/build')
| -rw-r--r-- | guix/build/syscalls.scm | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/guix/build/syscalls.scm b/guix/build/syscalls.scm index ac1b0c2eea..99a3b45004 100644 --- a/guix/build/syscalls.scm +++ b/guix/build/syscalls.scm @@ -7,6 +7,7 @@ ;;; Copyright © 2020 Julien Lepiller <julien@lepiller.eu> ;;; Copyright © 2020 Jan (janneke) Nieuwenhuizen <janneke@gnu.org> ;;; Copyright © 2021 Chris Marusich <cmmarusich@gmail.com> +;;; Copyright © 2021 Tobias Geerinckx-Rice <me@tobias.gr> ;;; ;;; This file is part of GNU Guix. ;;; @@ -56,6 +57,9 @@ restart-on-EINTR + device-number + device-number->major+minor + mount? mount-device-number mount-source @@ -450,6 +454,29 @@ the returned procedure is called." ;;; +;;; Block devices. +;;; + +;; Convert between major:minor pairs and packed ‘device number’ representation. +;; XXX These aren't syscalls, but if you squint very hard they are part of the +;; FFI or however you want to justify me not finding a better fit… :-) +(define (device-number major minor) ; see glibc's <sys/sysmacros.h> + "Return the device number for the device with MAJOR and MINOR, for use as +the last argument of `mknod'." + (logior (ash (logand #x00000fff major) 8) + (ash (logand #xfffff000 major) 32) + (logand #x000000ff minor) + (ash (logand #xffffff00 minor) 12))) + +(define (device-number->major+minor device) ; see glibc's <sys/sysmacros.h> + "Return two values: the major and minor device numbers that make up DEVICE." + (values (logior (ash (logand #x00000000000fff00 device) -8) + (ash (logand #xfffff00000000000 device) -32)) + (logior (logand #x00000000000000ff device) + (ash (logand #x00000ffffff00000 device) -12)))) + + +;;; ;;; File systems. ;;; @@ -628,7 +655,7 @@ current process." (define (string->device-number str) (match (string-split str #\:) (((= string->number major) (= string->number minor)) - (+ (* major 256) minor)))) + (device-number major minor)))) (call-with-input-file "/proc/self/mountinfo" (lambda (port) |