depot/ops/nixos/kerrigan/boot-builder.sh

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2023-01-17 19:36:53 +00:00
#! @bash@/bin/sh -e
shopt -s nullglob
export PATH=/empty
for i in @path@; do PATH=$PATH:$i/bin; done
usage() {
echo "usage: $0 -c <path-to-default-configuration> [-d <boot-dir>] [-g <num-generations>]" >&2
exit 1
}
default= # Default configuration
target=/boot # Target directory
numGenerations=0 # Number of other generations to include in the menu
while getopts "c:d:g:" opt; do
case "$opt" in
c) default="$OPTARG" ;;
d) target="$OPTARG" ;;
g) numGenerations="$OPTARG" ;;
\?) usage ;;
esac
done
[ "$default" = "" ] && usage
mkdir -p $target/nixos
# Convert a path to a file in the Nix store such as
# /nix/store/<hash>-<name>/file to <hash>-<name>-<file>.
cleanName() {
local path="$1"
echo "$path" | sed 's|^/nix/store/||' | sed 's|/|-|g'
}
# Copy a file from the Nix store to $target/nixos.
declare -A filesCopied
copyToKernelsDir() {
local src=$(readlink -f "$1")
local dst="$target/nixos/$(cleanName $src)"
# Don't copy the file if $dst already exists. This means that we
# have to create $dst atomically to prevent partially copied
# kernels or initrd if this script is ever interrupted.
if ! test -e $dst; then
local dstTmp=$dst.tmp.$$
cp -r $src $dstTmp
mv $dstTmp $dst
fi
filesCopied[$dst]=1
result=$dst
}
# Copy its kernel, initrd and dtbs to $target/nixos, and echo out an
# extlinux menu entry
addEntry() {
local path=$(readlink -f "$1")
local tag="$2" # Generation number or 'default'
if ! test -e $path/kernel -a -e $path/initrd; then
return
fi
copyToKernelsDir "$path/kernel"; kernel=$result
copyToKernelsDir "$path/initrd"; initrd=$result
dtbDir=$(readlink -m "$path/dtbs")
if [ -e "$dtbDir" ]; then
copyToKernelsDir "$dtbDir"; dtbs=$result
fi
timestampEpoch=$(stat -L -c '%Z' $path)
timestamp=$(date "+%Y-%m-%d %H:%M" -d @$timestampEpoch)
nixosLabel="$(cat $path/nixos-version)"
extraParams="$(cat $path/kernel-params)"
filesCopied[$target/nixos/$tag]=1
echo > $target/nixos/$tag.tmp
echo "ext4load usb 0:2 \$kernel_addr_r boot/nixos/$(basename $kernel)" >> $target/nixos/$tag.tmp
echo "ext4load usb 0:2 \$fdt_addr_r boot/nixos/$(basename $dtbs)/marvell/armada-7040-mochabin.dtb" >> $target/nixos/$tag.tmp
echo "ext4load usb 0:2 0xa700000 boot/nixos/$(basename $initrd)" >> $target/nixos/$tag.tmp
echo "setenv bootargs \$console init=$path/init $extraParams" >> $target/nixos/$tag.tmp
echo "booti \$kernel_addr_r 0xa700000:\$filesize \$fdt_addr_r" >> $target/nixos/$tag.tmp
mkimage -A arm64 -O u-boot -T script -C none -a 0 -e 0 -n "Boot Script ${nixosLabel} ${timestamp}" -d $target/nixos/$tag.tmp $target/nixos/$tag
}
addEntry $default default
if [ "$numGenerations" -gt 0 ]; then
# Add up to $numGenerations generations of the system profile to the menu,
# in reverse (most recent to least recent) order.
for generation in $(
(cd /nix/var/nix/profiles && ls -d system-*-link) \
| sed 's/system-\([0-9]\+\)-link/\1/' \
| sort -n -r \
| head -n $numGenerations); do
link=/nix/var/nix/profiles/system-$generation-link
addEntry $link $generation
done
fi
# Remove obsolete files from $target/nixos.
for fn in $target/nixos/*; do
if ! test "${filesCopied[$fn]}" = 1; then
echo "Removing no longer needed boot file: $fn"
chmod +w -- "$fn"
rm -rf -- "$fn"
fi
done