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#!/bin/sh
# Get the value of the root env variable found in /proc/cmdline
get_root() {
local root="$(cat /proc/cmdline)"
root="${root##* root=PARTLABEL=}"
root="${root%% *}"
[ "${root}" != "" ] && echo "${root}"
}
fslist="proc sys dev run"
rodir=/mnt/rofs
mmcdev="/dev/mmcblk0"
rwfsdev="/dev/disk/by-partlabel/rwfs"
cd /
mkdir -p $fslist
mount dev dev -tdevtmpfs
mount sys sys -tsysfs
mount proc proc -tproc
mount tmpfs run -t tmpfs -o mode=755,nodev
# Wait up to 5s for the mmc device to appear. Continue even if the count is
# exceeded. A failure will be caught later like in the mount command.
count=0
while [ $count -lt 5 ]; do
if [ -e "${mmcdev}" ]; then
break
fi
sleep 1
count=$((count + 1))
done
# Move the secondary GPT to the end of the device if needed. Look for the GPT
# header signature "EFI PART" located 512 bytes from the end of the device.
if ! tail -c 512 "${mmcdev}" | hexdump -C -n 8 | grep -q "EFI PART"; then
sgdisk -e "${mmcdev}"
partprobe
fi
# There eMMC GPT labels for the rootfs are rofs-a and rofs-b, and the label for
# the read-write partition is rwfs. Run udev to make the partition labels show
# up. Mounting by label allows for partition numbers to change if needed.
udevd --daemon
udevadm trigger --type=devices --action=add
udevadm settle --timeout=10
mkdir -p $rodir
if ! mount /dev/disk/by-partlabel/"$(get_root)" $rodir -t ext4 -o ro; then
/bin/sh
fi
# Determine if a factory reset has been requested
mkdir -p /var/lock
resetval=$(fw_printenv -n rwreset 2>/dev/null)
gpiopresent=$(gpiofind factory-reset-toggle)
if [ $? -eq 0 ]; then
gpioval=$(gpioget $gpiopresent)
else
gpioval=""
fi
# Prevent unnecessary resets on first boot
if [ -n "$gpioval" -a -z "$resetval" ]; then
fw_setenv rwreset $gpioval
resetval=$gpioval
fi
if [ "$resetval" = "true" -o -n "$gpioval" -a "$resetval" != "$gpioval" ]; then
echo "Factory reset requested."
if ! mkfs.ext4 -F "${rwfsdev}"; then
echo "Reformat for factory reset failed."
/bin/sh
else
# gpioval will be an empty string if factory-reset-toggle was not found
fw_setenv rwreset $gpioval
echo "rwfs has been formatted."
fi
fi
fsck.ext4 -p "${rwfsdev}"
if ! mount "${rwfsdev}" $rodir/var -t ext4 -o rw; then
/bin/sh
fi
rm -rf $rodir/var/persist/etc-work/
mkdir -p $rodir/var/persist/etc $rodir/var/persist/etc-work $rodir/var/persist/home/root
mount overlay $rodir/etc -t overlay -o lowerdir=$rodir/etc,upperdir=$rodir/var/persist/etc,workdir=$rodir/var/persist/etc-work
for f in $fslist; do
mount --move $f $rodir/$f
done
exec switch_root $rodir /sbin/init
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