grub2/grub2-once

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#!/usr/bin/perl
#
# (C) 2014 mchang@suse.com
#
# 2014-02-20 jw@suse.de
use strict;
my $grub2_dir;
my $grub2_reboot;
my $grub2_editenv;
my $show_mapped;
my $id_name;
my @menuentry;
my @enumentry;
my %E;
sub dPrint($) {
#print( STDERR @_[0]);
}
sub sh_test($) {
my ( $exp ) = @_;
dPrint( "?? '$exp' ");
# Don't test grub command return status from linux shell, this often results
# in command not found error. In such case the expression often has no
# opening bracket and just returning false here to signify -ENOCMD error.
return 0 if ( $exp =~ m{^\s*[^\[]});
$exp .= " ]" if ( $exp =~ m{^\[.*[^\]]\s*$} ); # gnaaa
#my $t = qx{set -x; $exp};
my $t = qx{$exp};
my $ret = $? >> 8;
$ret = ($ret == 0) ? 1 : 0;
dPrint("=> $ret ($t)\n");
return $ret;
}
sub read_cfg($$) {
my ($dir, $cfg) = @_;
my $fh;
my $m = "";
my $state = 1; # 1 == normal, 010 == if-false, 011 == if-true, 110 == else-false, 111 == else-true
my @State = ();
if ($dir) {
%E = ( "config_directory" => $dir );
dPrint("# VE: 'cd'='$dir'\n");
$dir .= "/";
if ($> == 0) {
open($fh, "$grub2_editenv - list |") || die "cannot read grub2 environment: $!\n";
while (<$fh>) {
chomp;
if ( m{^([^\s=]+?)=(.*)$} ) {
my ($k, $v) = ($1, $2);
$v =~ s{^"([^"]*)"$}{$1};
dPrint("# VE: '$k'='$v'\n");
$E{$k} = $v;
}
}
close($fh);
}
}
dPrint("# open($dir$cfg)\n");
open($fh, "<$dir$cfg") || die "cannot read $cfg in $dir: $!\n";
LINE: while ( <$fh> ) {
s{^#.*$}{}; # get rid of trailing comments,
s{\s+$}{}; # trailing whitespace
s{\s*;$}{}; # including semicolons
next if (m{^\s*$}); # and empty lines.
s{^\s*}{ }; # force leading whitespace to one
dPrint(sprintf("#%d: '%s' [%s]%04b\n", $., $_, join(",",@State), $state));
if ( m{^ fi$} ) {
$state = pop( @State);
$m .= "$_\n";
dPrint(sprintf(">FI: [%s]0b%04b\n", join(",",@State), $state));
next;
}
if ($state & 0b10) { # {if,else}-*
if ( m{^ elif\s+(.*?)\s*; then$} && !($state & 0b1000)) {
if ($state & 0b1) {
$state = 0b110; # else-false
} else {
$state = 0b010 + sh_test( $1); # if-?
dPrint(sprintf("=EI: 0b%03b\n", $state));
$m .= "$_\n";
next;
}
} elsif ( m{^ else$} && !($state & 0b1000)) {
if (($state & 0b111) == 0b010) { # in 'if' but neither 'else' nor 'true'
$state = 0b111; # else-true
} else {
$state = 0b110; # else-false
}
$m .= "$_\n";
dPrint(sprintf("=EL: 0b%03b\n", $state));
next;
}
}
if ($state & 0b1) { # *-true or normal
dPrint("-I1: $_\n");
} else { # *-false
dPrint("-I0: $_\n");
if ( m{^ if (.*?)\s*; then$} ) {
push( @State, $state);
$state = 0b1000;
$m .= "$_\n";
}
next;
}
while ( m'(?:[^\\])(\$(?:{([^}]+?)}|([A-Za-z0-9_]+)))' ) {
my ($s, $k1, $k2) = ($1, $2, $3);
my $k = (defined($k1)) ? $k1 : $k2;
dPrint("# VT: '$k'\n");
if (exists( $E{$k})) {
$s =~ s{([\$\{\}\"])}{\\$1}g;
dPrint("# VB: '$_'\n");
s{$s}{$E{$k}} || die;
dPrint("# VR: '$_'\n");
} else {
$s =~ s{([\$\{\}\"])}{\\$1}g;
s{$s}{} || die;
dPrint("# VR: '$_'\n");
}
}
if ( m{^ if (.*?)\s*; then$} ) {
push( @State, $state);
$state = 0b010 + sh_test( $1);
dPrint(sprintf("<IF: 0b%03b [%s]\n", $state, join (",", @State)));
} elsif ( m{^ (?:set\s+)?([^\s=]+?)=(.*)$} ) {
my ($k, $v) = ($1, $2);
$v =~ s{^"([^"]*)"$}{$1};
dPrint("# VA: '$k'='$v'\n");
$E{$k} = $v;
} elsif ( m{^ source\s+(\S+)$} ) {
my $f = $1;
$f =~ s{^"([^"]+)"$}{$1} &&
dPrint("# f='$f'\n");
if ( -r $f ) {
$m .= read_cfg("", $f);
}
next;
}
$m .= "$_\n";
}
close ($fh);
return ($m);
}
sub parse_menuentry($$$) {
my ($parent, $pId, $menu) = @_;
my $c = 0;
my @m = $menu =~ /(submenu|menuentry) \s+ (.*?) ( \{ (?: [^{}]* | (?3))* \} )/sxg;
for (my $i = 0; $i <= $#m; $i += 3) {
my $type = $m[$i];
my $title = `printf "%s\n" $m[$i+1] | head -1 | tr -d '\n'`;
my $data = $m[$i+2];
my $name = ($parent) ? "$parent>$title" : "$title";
my $eId = (($pId ne "") ? "$pId>" : "") . $c++;
if ($type eq "menuentry") {
push @menuentry, $name;
push @enumentry, [$name, $eId];
} elsif ($type eq "submenu") {
parse_menuentry ($name, $eId, $data);
}
}
}
# Enable restore grubenv service (bnc#892358)
# Restore grubenv settings for booting default entry to workaround the grub2-once cannot
# work and function properly on lvm, md and s390.
sub enable_restore_grubenv_service {
my $systemctl = "/usr/bin/systemctl";
my $cleanup = "/var/lib/misc/grub2-cleanup-once";
unless (-e $cleanup) {
open(my $fh, ">", $cleanup) or die "open: $cleanup $!\n";
close($fh);
}
return 0 if (system("$systemctl --quiet is-enabled grub2-once") == 0);
system "$systemctl --no-reload enable grub2-once >/dev/null 2>&1";
}
$id_name = "";
if (@ARGV == 2 && ($ARGV[0] eq "--show-mapped")) {
$show_mapped = 1;
$id_name = $ARGV[1];
} elsif (@ARGV == 1) {
$show_mapped = 0;
$id_name = $ARGV[0];
}
die "wrong command line options, try --help\n" if ($id_name eq "");
open(SYSCONF, "</etc/sysconfig/bootloader") || die "cannot read bootloader sysconfig: $!\n";
$grub2_dir = "";
while (<SYSCONF>) {
chomp;
next if ( /^\s*#/ );
if ( /LOADER_TYPE=(\'|\"|)([^\'\"\s]+)\1(\s*|\s+#.*)$/ ) {
dPrint("OK : $2\n");
if ($2 eq "grub2" || $2 eq "grub2-efi") {
# Found grub2 to be the incumbent loader ...
$grub2_dir = "/boot/grub2";
$grub2_reboot = "/usr/sbin/grub2-reboot";
$grub2_editenv = "/usr/bin/grub2-editenv";
# Note : Here we continues rather than exiting the loop, which
# results in different behavior than previous "the first wins". Now
# the latest defined LOADER_TYPE can be used to override any
# previous one, which is identical to the result of regular shell
# variable expansion to meet most people's expectation.
}
} else {
next if ( /^\s*$/ );
dPrint("SKIP: <$_>\n");
}
}
close (SYSCONF);
if ($id_name eq "--help" or $id_name eq "-h")
{
print "Usage: grub2-once [--show-mapped ID | --list | ID | NAME_SUBSTRING ]\n";
system "$grub2_reboot \"--help\"";
exit 0;
}
die "no grub2_dir" if ($grub2_dir eq "");
my $m = read_cfg( $grub2_dir, "grub.cfg");
# Note: only *one* top-level call to parse_menuentry() is possible
# or else it will start again with 0 (and no parent)!
parse_menuentry ("", "", $m);
my $ret = "";
my $name = "";
my $id = -1;
if ($id_name eq '--enum') {
foreach my $e (@enumentry) {
printf "%-7s %s\n", $e->[1], $e->[0];
}
exit 0;
}
if ($id_name eq '--list')
{
my $c = 0;
foreach my $e (@menuentry)
{
printf "%6d %s\n", $c, $e;
$c++;
}
exit 0;
}
if ($id_name =~ m!^[0-9]+$!) {
if ($id_name < @menuentry) {
$id = $id_name;
$name = $menuentry[$id];
$ret = $name;
}
} else {
my $i = -1;
my $c = 0;
$name = $id_name;
foreach my $e (@menuentry) {
if ($e =~ qr!\Q$name\E!) {
$i = $c;
last;
}
} continue {
++$c;
}
if ($i >= 0) {
$id = $i;
$name = $menuentry[$id];
$ret = "$id";
}
}
if ($show_mapped > 0) {
print $ret;
} else {
system "$grub2_reboot \"$name\"";
enable_restore_grubenv_service;
}