From f59f0ae6f9e4ac56dbb2c6f12dfb5251d974565d Mon Sep 17 00:00:00 2001
From: Stefan Wagner <stw@bit-strickerei.de>
Date: Sun, 30 Oct 2016 14:18:30 +0100
Subject: mkinitfs: add support for resume

This patch tries to add resume from hibernation (aka suspend to disk)
support to mkinitfs. The swap partition can be provided via the resume
option.

The default Alpine Linux kernel has no hibernation support compiled in,
so a custom kernel is needed in order to use this.

Some links on the topic:
* https://wiki.gentoo.org/wiki/Custom_Initramfs/Hibernation
* https://git.archlinux.org/mkinitcpio.git/tree/hooks/resume
---
 initramfs-init.in | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

(limited to 'initramfs-init.in')

diff --git a/initramfs-init.in b/initramfs-init.in
index 50dc844..64b1b5b 100755
--- a/initramfs-init.in
+++ b/initramfs-init.in
@@ -263,7 +263,7 @@ set -- $(cat /proc/cmdline)
 myopts="alpine_dev autodetect autoraid chart cryptroot cryptdm debug_init
 	dma init_args keep_apk_new modules ovl_dev pkgs quiet root_size root
 	usbdelay ip alpine_repo apkovl alpine_start splash blacklist
-	overlaytmpfs rootfstype rootflags nbd"
+	overlaytmpfs rootfstype rootflags nbd resume"
 
 for opt; do
 	case "$opt" in
@@ -371,16 +371,25 @@ if [ -n "$KOPT_root" ]; then
 	fi
 
 	ebegin "Mounting root"
+	nlplug-findfs $cryptopts -p /sbin/mdev $KOPT_root
+
+	if [ -n "$KOPT_resume" ]; then
+		echo "Resume from disk"
+		if [ -e /sys/power/resume ]; then
+			printf "%d:%d" $(stat -Lc "0x%t 0x%T" "$KOPT_resume") >/sys/power/resume
+		else
+			echo "resume: no hibernation support found"
+		fi
+	fi
+
 	if [ "$KOPT_overlaytmpfs" = "yes" ]; then
 		mkdir -p /media/root-ro /media/root-rw $sysroot/media/root-ro \
 			$sysroot/media/root-rw
-		nlplug-findfs $cryptopts -p /sbin/mdev $KOPT_root \
-			&& mount -o ro $KOPT_root /media/root-ro
+		mount -o ro $KOPT_root /media/root-ro
 		mount -t tmpfs root-tmpfs /media/root-rw
 		mkdir -p /media/root-rw/work /media/root-rw/root
 		mount -t overlay -o lowerdir=/media/root-ro,upperdir=/media/root-rw/root,workdir=/media/root-rw/work overlayfs $sysroot
 	else
-		nlplug-findfs $cryptopts -p /sbin/mdev $KOPT_root
 		mount ${KOPT_rootfstype:+-t} ${KOPT_rootfstype} \
 			-o ${KOPT_rootflags:-ro} \
 			$KOPT_root $sysroot
-- 
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