nixpkgs/nixos/modules/system/boot/loader/grub/install-grub.pl
Shea Levy e4630c1d41 grub: Allow setting the boot root explicitly
If /boot is a btrfs subvolume, it will be on a different device than /
but not be at the root from grub's perspective. This should be fixed in
a nicer way by #2449, but that can't go into 14.04.
2014-05-01 10:56:55 -04:00

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use strict;
use warnings;
use XML::LibXML;
use File::Basename;
use File::Path;
use File::stat;
use File::Copy;
use POSIX;
use Cwd;
my $defaultConfig = $ARGV[1] or die;
my $dom = XML::LibXML->load_xml(location => $ARGV[0]);
sub get { my ($name) = @_; return $dom->findvalue("/expr/attrs/attr[\@name = '$name']/*/\@value"); }
sub readFile {
my ($fn) = @_; local $/ = undef;
open FILE, "<$fn" or return undef; my $s = <FILE>; close FILE;
local $/ = "\n"; chomp $s; return $s;
}
sub writeFile {
my ($fn, $s) = @_;
open FILE, ">$fn" or die "cannot create $fn: $!\n";
print FILE $s or die;
close FILE or die;
}
my $grub = get("grub");
my $grubVersion = int(get("version"));
my $extraConfig = get("extraConfig");
my $extraPrepareConfig = get("extraPrepareConfig");
my $extraPerEntryConfig = get("extraPerEntryConfig");
my $extraEntries = get("extraEntries");
my $extraEntriesBeforeNixOS = get("extraEntriesBeforeNixOS") eq "true";
my $splashImage = get("splashImage");
my $configurationLimit = int(get("configurationLimit"));
my $copyKernels = get("copyKernels") eq "true";
my $timeout = int(get("timeout"));
my $defaultEntry = int(get("default"));
my $explicitBootRoot = get("explicitBootRoot");
$ENV{'PATH'} = get("path");
die "unsupported GRUB version\n" if $grubVersion != 1 && $grubVersion != 2;
print STDERR "updating GRUB $grubVersion menu...\n";
mkpath("/boot/grub", 0, 0700);
# Discover whether /boot is on the same filesystem as / and
# /nix/store. If not, then all kernels and initrds must be copied to
# /boot, and all paths in the GRUB config file must be relative to the
# root of the /boot filesystem. `$bootRoot' is the path to be
# prepended to paths under /boot.
my $bootRoot = "/boot";
if (stat("/")->dev != stat("/boot")->dev) {
$bootRoot = "";
$copyKernels = 1;
} elsif (stat("/boot")->dev != stat("/nix/store")->dev) {
$copyKernels = 1;
}
if ($explicitBootRoot ne "") {
$bootRoot = $explicitBootRoot;
}
# Generate the header.
my $conf .= "# Automatically generated. DO NOT EDIT THIS FILE!\n";
if ($grubVersion == 1) {
$conf .= "
default $defaultEntry
timeout $timeout
";
if ($splashImage) {
copy $splashImage, "/boot/background.xpm.gz" or die "cannot copy $splashImage to /boot\n";
$conf .= "splashimage $bootRoot/background.xpm.gz\n";
}
}
else {
$conf .= "
if [ -s \$prefix/grubenv ]; then
load_env
fi
# grub-reboot sets a one-time saved entry, which we process here and
# then delete.
if [ \"\${saved_entry}\" ]; then
# The next line *has* to look exactly like this, otherwise KDM's
# reboot feature won't work properly with GRUB 2.
set default=\"\${saved_entry}\"
set saved_entry=
set prev_saved_entry=
save_env saved_entry
save_env prev_saved_entry
set timeout=1
else
set default=$defaultEntry
set timeout=$timeout
fi
if loadfont $bootRoot/grub/fonts/unicode.pf2; then
set gfxmode=640x480
insmod gfxterm
insmod vbe
terminal_output gfxterm
fi
";
if ($splashImage) {
# FIXME: GRUB 1.97 doesn't resize the background image if it
# doesn't match the video resolution.
copy $splashImage, "/boot/background.png" or die "cannot copy $splashImage to /boot\n";
$conf .= "
insmod png
if background_image $bootRoot/background.png; then
set color_normal=white/black
set color_highlight=black/white
else
set menu_color_normal=cyan/blue
set menu_color_highlight=white/blue
fi
";
}
}
$conf .= "$extraConfig\n";
# Generate the menu entries.
$conf .= "\n";
my %copied;
mkpath("/boot/kernels", 0, 0755) if $copyKernels;
sub copyToKernelsDir {
my ($path) = @_;
return $path unless $copyKernels;
$path =~ /\/nix\/store\/(.*)/ or die;
my $name = $1; $name =~ s/\//-/g;
my $dst = "/boot/kernels/$name";
# 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 (! -e $dst) {
my $tmp = "$dst.tmp";
copy $path, $tmp or die "cannot copy $path to $tmp\n";
rename $tmp, $dst or die "cannot rename $tmp to $dst\n";
}
$copied{$dst} = 1;
return "$bootRoot/kernels/$name";
}
sub addEntry {
my ($name, $path) = @_;
return unless -e "$path/kernel" && -e "$path/initrd";
my $kernel = copyToKernelsDir(Cwd::abs_path("$path/kernel"));
my $initrd = copyToKernelsDir(Cwd::abs_path("$path/initrd"));
my $xen = -e "$path/xen.gz" ? copyToKernelsDir(Cwd::abs_path("$path/xen.gz")) : undef;
# FIXME: $confName
my $kernelParams =
"systemConfig=" . Cwd::abs_path($path) . " " .
"init=" . Cwd::abs_path("$path/init") . " " .
readFile("$path/kernel-params");
my $xenParams = $xen && -e "$path/xen-params" ? readFile("$path/xen-params") : "";
if ($grubVersion == 1) {
$conf .= "title $name\n";
$conf .= " $extraPerEntryConfig\n" if $extraPerEntryConfig;
$conf .= " kernel $xen $xenParams\n" if $xen;
$conf .= " " . ($xen ? "module" : "kernel") . " $kernel $kernelParams\n";
$conf .= " " . ($xen ? "module" : "initrd") . " $initrd\n\n";
} else {
$conf .= "menuentry \"$name\" {\n";
$conf .= " $extraPerEntryConfig\n" if $extraPerEntryConfig;
$conf .= " multiboot $xen $xenParams\n" if $xen;
$conf .= " " . ($xen ? "module" : "linux") . " $kernel $kernelParams\n";
$conf .= " " . ($xen ? "module" : "initrd") . " $initrd\n";
$conf .= "}\n\n";
}
}
# Add default entries.
$conf .= "$extraEntries\n" if $extraEntriesBeforeNixOS;
addEntry("NixOS - Default", $defaultConfig);
$conf .= "$extraEntries\n" unless $extraEntriesBeforeNixOS;
# extraEntries could refer to @bootRoot@, which we have to substitute
$conf =~ s/\@bootRoot\@/$bootRoot/g;
# Emit submenus for all system profiles.
sub addProfile {
my ($profile, $description) = @_;
# Add entries for all generations of this profile.
$conf .= "submenu \"$description\" {\n" if $grubVersion == 2;
sub nrFromGen { my ($x) = @_; $x =~ /\/\w+-(\d+)-link/; return $1; }
my @links = sort
{ nrFromGen($b) <=> nrFromGen($a) }
(glob "$profile-*-link");
my $curEntry = 0;
foreach my $link (@links) {
last if $curEntry++ >= $configurationLimit;
my $date = strftime("%F", localtime(lstat($link)->mtime));
my $version =
-e "$link/nixos-version"
? readFile("$link/nixos-version")
: basename((glob(dirname(Cwd::abs_path("$link/kernel")) . "/lib/modules/*"))[0]);
addEntry("NixOS - Configuration " . nrFromGen($link) . " ($date - $version)", $link);
}
$conf .= "}\n" if $grubVersion == 2;
}
addProfile "/nix/var/nix/profiles/system", "NixOS - All configurations";
if ($grubVersion == 2) {
for my $profile (glob "/nix/var/nix/profiles/system-profiles/*") {
my $name = basename($profile);
next unless $name =~ /^\w+$/;
addProfile $profile, "NixOS - Profile '$name'";
}
}
# Run extraPrepareConfig in sh
if ($extraPrepareConfig ne "") {
system((get("shell"), "-c", $extraPrepareConfig));
}
# Atomically update the GRUB config.
my $confFile = $grubVersion == 1 ? "/boot/grub/menu.lst" : "/boot/grub/grub.cfg";
my $tmpFile = $confFile . ".tmp";
writeFile($tmpFile, $conf);
rename $tmpFile, $confFile or die "cannot rename $tmpFile to $confFile\n";
# Remove obsolete files from /boot/kernels.
foreach my $fn (glob "/boot/kernels/*") {
next if defined $copied{$fn};
print STDERR "removing obsolete file $fn\n";
unlink $fn;
}
# Install GRUB if the version changed from the last time we installed
# it. FIXME: shouldn't we reinstall if devices changed?
my $prevVersion = readFile("/boot/grub/version") // "";
if (($ENV{'NIXOS_INSTALL_GRUB'} // "") eq "1" || get("fullVersion") ne $prevVersion) {
foreach my $dev ($dom->findnodes('/expr/attrs/attr[@name = "devices"]/list/string/@value')) {
$dev = $dev->findvalue(".") or die;
next if $dev eq "nodev";
print STDERR "installing the GRUB $grubVersion boot loader on $dev...\n";
system("$grub/sbin/grub-install", "--recheck", Cwd::abs_path($dev)) == 0
or die "$0: installation of GRUB on $dev failed\n";
}
writeFile("/boot/grub/version", get("fullVersion"));
}