nixos/modules/system/boot/loader/generic-extlinux-compatible/extlinux-conf-builder.sh

   1 #! @bash@/bin/sh -e
   2
   3 shopt -s nullglob
   4
   5 export PATH=/empty
   6 for i in @path@; do PATH=$PATH:$i/bin; done
   7
   8 usage() {
   9     echo "usage: $0 -t <timeout> -c <path-to-default-configuration> [-d <boot-dir>] [-g <num-generations>] [-n <dtbName>] [-r]" >&2
  10     exit 1
  11 }
  12
  13 timeout=                # Timeout in centiseconds
  14 default=                # Default configuration
  15 target=/boot            # Target directory
  16 numGenerations=0        # Number of other generations to include in the menu
  17
  18 while getopts "t:c:d:g:n:r" opt; do
  19     case "$opt" in
  20         t) # U-Boot interprets '0' as infinite and negative as instant boot
  21             if [ "$OPTARG" -lt 0 ]; then
  22                 timeout=0
  23             elif [ "$OPTARG" = 0 ]; then
  24                 timeout=-10
  25             else
  26                 timeout=$((OPTARG * 10))
  27             fi
  28             ;;
  29         c) default="$OPTARG" ;;
  30         d) target="$OPTARG" ;;
  31         g) numGenerations="$OPTARG" ;;
  32         n) dtbName="$OPTARG" ;;
  33         r) noDeviceTree=1 ;;
  34         \?) usage ;;
  35     esac
  36 done
  37
  38 [ "$timeout" = "" -o "$default" = "" ] && usage
  39
  40 mkdir -p $target/nixos
  41 mkdir -p $target/extlinux
  42
  43 # Convert a path to a file in the Nix store such as
  44 # /nix/store/<hash>-<name>/file to <hash>-<name>-<file>.
  45 cleanName() {
  46     local path="$1"
  47     echo "$path" | sed 's|^/nix/store/||' | sed 's|/|-|g'
  48 }
  49
  50 # Copy a file from the Nix store to $target/nixos.
  51 declare -A filesCopied
  52
  53 copyToKernelsDir() {
  54     local src=$(readlink -f "$1")
  55     local dst="$target/nixos/$(cleanName $src)"
  56     # Don't copy the file if $dst already exists.  This means that we
  57     # have to create $dst atomically to prevent partially copied
  58     # kernels or initrd if this script is ever interrupted.
  59     if ! test -e $dst; then
  60         local dstTmp=$dst.tmp.$$
  61         cp -r $src $dstTmp
  62         mv $dstTmp $dst
  63     fi
  64     filesCopied[$dst]=1
  65     result=$dst
  66 }
  67
  68 # Copy its kernel, initrd and dtbs to $target/nixos, and echo out an
  69 # extlinux menu entry
  70 addEntry() {
  71     local path=$(readlink -f "$1")
  72     local tag="$2" # Generation number or 'default'
  73
  74     if ! test -e $path/kernel -a -e $path/initrd; then
  75         return
  76     fi
  77
  78     copyToKernelsDir "$path/kernel"; kernel=$result
  79     copyToKernelsDir "$path/initrd"; initrd=$result
  80     dtbDir=$(readlink -m "$path/dtbs")
  81     if [ -e "$dtbDir" ]; then
  82         copyToKernelsDir "$dtbDir"; dtbs=$result
  83     fi
  84
  85     timestampEpoch=$(stat -L -c '%Z' $path)
  86
  87     timestamp=$(date "+%Y-%m-%d %H:%M" -d @$timestampEpoch)
  88     nixosLabel="$(cat $path/nixos-version)"
  89     extraParams="$(cat $path/kernel-params)"
  90
  91     echo
  92     echo "LABEL nixos-$tag"
  93     if [ "$tag" = "default" ]; then
  94         echo "  MENU LABEL NixOS - Default"
  95     else
  96         echo "  MENU LABEL NixOS - Configuration $tag ($timestamp - $nixosLabel)"
  97     fi
  98     echo "  LINUX ../nixos/$(basename $kernel)"
  99     echo "  INITRD ../nixos/$(basename $initrd)"
 100     echo "  APPEND init=$path/init $extraParams"
 101
 102     if [ -n "$noDeviceTree" ]; then
 103         return
 104     fi
 105
 106     if [ -d "$dtbDir" ]; then
 107         # if a dtbName was specified explicitly, use that, else use FDTDIR
 108         if [ -n "$dtbName" ]; then
 109             echo "  FDT ../nixos/$(basename $dtbs)/${dtbName}"
 110         else
 111             echo "  FDTDIR ../nixos/$(basename $dtbs)"
 112         fi
 113     else
 114         if [ -n "$dtbName" ]; then
 115             echo "Explicitly requested dtbName $dtbName, but there's no FDTDIR - bailing out." >&2
 116             exit 1
 117         fi
 118     fi
 119 }
 120
 121 tmpFile="$target/extlinux/extlinux.conf.tmp.$$"
 122
 123 cat > $tmpFile <<EOF
 124 # Generated file, all changes will be lost on nixos-rebuild!
 125
 126 # Change this to e.g. nixos-42 to temporarily boot to an older configuration.
 127 DEFAULT nixos-default
 128
 129 MENU TITLE ------------------------------------------------------------
 130 TIMEOUT $timeout
 131 EOF
 132
 133 addEntry $default default >> $tmpFile
 134
 135 if [ "$numGenerations" -gt 0 ]; then
 136     # Add up to $numGenerations generations of the system profile to the menu,
 137     # in reverse (most recent to least recent) order.
 138     for generation in $(
 139             (cd /nix/var/nix/profiles && ls -d system-*-link) \
 140             | sed 's/system-\([0-9]\+\)-link/\1/' \
 141             | sort -n -r \
 142             | head -n $numGenerations); do
 143         link=/nix/var/nix/profiles/system-$generation-link
 144         addEntry $link "${generation}-default"
 145         for specialisation in $(
 146             ls /nix/var/nix/profiles/system-$generation-link/specialisation \
 147             | sort -n -r); do
 148             link=/nix/var/nix/profiles/system-$generation-link/specialisation/$specialisation
 149             addEntry $link "${generation}-${specialisation}"
 150         done
 151     done >> $tmpFile
 152 fi
 153
 154 mv -f $tmpFile $target/extlinux/extlinux.conf
 155
 156 # Remove obsolete files from $target/nixos.
 157 for fn in $target/nixos/*; do
 158     if ! test "${filesCopied[$fn]}" = 1; then
 159         echo "Removing no longer needed boot file: $fn"
 160         chmod +w -- "$fn"
 161         rm -rf -- "$fn"
 162     fi
 163 done