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-rw-r--r--gnu/build/linux-boot.scm59
1 files changed, 59 insertions, 0 deletions
diff --git a/gnu/build/linux-boot.scm b/gnu/build/linux-boot.scm
index 32e3536039..bfaac9ec1f 100644
--- a/gnu/build/linux-boot.scm
+++ b/gnu/build/linux-boot.scm
@@ -1,5 +1,6 @@
;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015, 2016, 2017, 2018, 2019, 2020 Ludovic Courtès <ludo@gnu.org>
+;;; Copyright © 2016, 2017, 2019, 2020 Tobias Geerinckx-Rice <me@tobias.gr>
;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com>
;;; Copyright © 2019 Guillaume Le Vaillant <glv@posteo.net>
;;;
@@ -110,6 +111,58 @@ OPTION doesn't appear in ARGUMENTS."
(substring arg (+ 1 (string-index arg #\=)))))
arguments)))
+(define (resume-if-hibernated device)
+ "Resume from hibernation if possible. This is safe ONLY if no on-disk file
+systems have been mounted; calling it later risks severe file system corruption!
+See <Documentation/swsusp.txt> in the kernel source directory. This is the
+caller's responsibility, as is catching exceptions if resumption was supposed to
+happen but didn't.
+
+Resume only from DEVICE if it's a string. If it's #f, use the kernel's default
+hibernation device (CONFIG_PM_STD_PARTITION). Never return if resumption
+succeeds. Return nothing otherwise. The kernel logs any details to dmesg."
+
+ (define (string->major:minor string)
+ "Return a string with MAJOR:MINOR numbers of the device specified by STRING"
+
+ ;; The "resume=" kernel command-line option always provides a string, which
+ ;; can represent a device, a UUID, or a label. Check for all three.
+ (let* ((spec (cond ((string-prefix? "/" string) string)
+ ((uuid string) => identity)
+ (else (file-system-label string))))
+ ;; XXX The kernel's swsusp_resume_can_resume() waits if ‘resumewait’
+ ;; is found on the command line; our canonicalize-device-spec gives
+ ;; up after 20 seconds. We could emulate the former by looping…
+ (device (canonicalize-device-spec spec))
+ (rdev (stat:rdev (stat device)))
+ ;; For backwards compatibility, device numbering is a baroque affair.
+ ;; This is the full 64-bit scheme used by glibc's <sys/sysmacros.h>.
+ (major (logior (ash (logand #x00000000000fff00 rdev) -8)
+ (ash (logand #xfffff00000000000 rdev) -32)))
+ (minor (logior (logand #x00000000000000ff rdev)
+ (ash (logand #x00000ffffff00000 rdev) -12))))
+ (format #f "~a:~a" major minor)))
+
+ ;; Write the resume DEVICE to this magic file, using the MAJOR:MINOR device
+ ;; numbers if possible. The kernel will immediately try to resume from it.
+ (let ((resume "/sys/power/resume"))
+ (when (file-exists? resume) ; this kernel supports hibernation
+ ;; Honour the kernel's default device (only) if none other was given.
+ (let ((major:minor (if device
+ (or (false-if-exception (string->major:minor
+ device))
+ ;; We can't parse it. Maybe the kernel can.
+ device)
+ (let ((default (call-with-input-file resume
+ read-line)))
+ ;; Don't waste time echoing 0:0 to /sys.
+ (if (string=? "0:0" default)
+ #f
+ default)))))
+ (when major:minor
+ (call-with-output-file resume ; may throw an ‘Invalid argument’
+ (cut display major:minor <>))))))) ; may never return
+
(define* (make-disk-device-nodes base major #:optional (minor 0))
"Make the block device nodes around BASE (something like \"/root/dev/sda\")
with the given MAJOR number, starting with MINOR."
@@ -507,6 +560,12 @@ upon error."
(load-linux-modules-from-directory linux-modules
linux-module-directory)
+ (unless (member "noresume" args)
+ ;; Try to resume immediately after loading (storage) modules
+ ;; but before any on-disk file systems have been mounted.
+ (false-if-exception ; failure is not fatal
+ (resume-if-hibernated (find-long-option "resume" args))))
+
(when keymap-file
(let ((status (system* "loadkeys" keymap-file)))
(unless (zero? status)