ksplice-undo.in

   1 #!/usr/bin/perl
   2
   3 # Copyright (C) 2007-2008  Jeffrey Brian Arnold <jbarnold@mit.edu>
   4 # Copyright (C) 2008  Anders Kaseorg <andersk@mit.edu>,
   5 #                     Tim Abbott <tabbott@mit.edu>
   6 #
   7 # This program is free software; you can redistribute it and/or modify
   8 # it under the terms of the GNU General Public License, version 2.
   9 #
  10 # This program is distributed in the hope that it will be useful,
  11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13 # GNU General Public License for more details.
  14 #
  15 # You should have received a copy of the GNU General Public License
  16 # along with this program; if not, write to the Free Software
  17 # Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
  18 # 02110-1301, USA.
  19
  20 use strict;
  21 use warnings;
  22 use lib 'KSPLICE_DATA_DIR';
  23 use Ksplice;
  24
  25 my ($help, $wantversion, $debug) = (0, 0, 0);
  26 GetOptions("help|?" => \$help,
  27         "version" => \$wantversion,
  28         "verbose|v:+" => \$Verbose::level,
  29         "debug" => \$debug) or pod2usage(1);
  30
  31 if($wantversion) {
  32         print $version_str;
  33         exit(0);
  34 }
  35 pod2usage(1) if($help || scalar(@ARGV) != 1);
  36
  37 my $kid = $ARGV[0];
  38 $kid =~ s/^ksplice[-_]//;
  39 $kid =~ s/[-_].*$//;
  40 my $update = "ksplice_$kid";
  41 my $nounload = runstr("lsmod") =~ m/- $/m;
  42
  43 if (!update_loaded($kid)) {
  44         print "Ksplice id $kid is not present in the kernel\n";
  45         exit(1);
  46 }
  47
  48 chdir("/sys/module/");
  49 set_debug_level($kid, $debug) if(defined($debug));
  50 my $stage = get_stage($kid);
  51 if ($stage ne 'applied') {
  52         print "Ksplice id $kid is not applied\n";
  53 }
  54 else {
  55         set_stage($kid, "reversed");
  56 }
  57
  58 my $failed = 0;
  59 foreach my $module (glob("${update}_*")) {
  60         if (!$nounload && runval_raw('rmmod', $module) != 0) {
  61                 child_error();
  62                 $failed = 1;
  63         }
  64 }
  65 if ($failed == 0 && -e "/sys/module/$update") {
  66         if (!$nounload && runval_raw('rmmod', $update) != 0) {
  67                 child_error();
  68                 $failed = 1;
  69         }
  70 }
  71 unless($failed == 0) {
  72         my ($debugfile, $debugout) = get_debug_output($kid);
  73         print STDERR "Error undoing Ksplice update $kid:\n";
  74         print $debugout;
  75         my $abort_cause = get_abort_cause($kid);
  76         my $conflicts = get_conflicts($kid);
  77         print_error($abort_cause);
  78         if ($abort_cause eq 'code_busy') {
  79                 print $conflicts;
  80         }
  81         print("Debugging output saved to $debugout\n");
  82         die;
  83 }
  84 exit(0);
  85
  86 sub print_error {
  87         my ($error) = @_;
  88         my %errors = (
  89                 "code_busy" => <<'END',
  90 Ksplice has aborted the undo operation because it appears that the code that
  91 you are trying to change is continuously in use by the system.  More
  92 specifically, Ksplice has been unable to find a moment when one or more of the
  93 to-be-changed functions is not on a thread's kernel stack.
  94 END
  95                 "module_busy" => <<'END',
  96 Ksplice has aborted the undo operation because it appears that the Ksplice
  97 update that you are trying to unload is in use by another module.  You can find
  98 out what module is using the Ksplice update using the lsmod command.
  99 END
 100                 "unexpected_running_task" => <<'END',
 101 Ksplice has aborted the undo operation because of an unexpected failure during
 102 the kernel stack check.  Please consider reporting a bug to PACKAGE_BUGREPORT.
 103 END
 104                 "out_of_memory" => <<'END',
 105 Ksplice has aborted the undo operation because the kernel ran out of memory.
 106 END
 107                 "unexpected" => <<'END',
 108 Ksplice has aborted because of an unexpected error.
 109 Please consider reporting a bug to PACKAGE_BUGREPORT.
 110 END
 111                 "UNKNOWN" => <<'END',
 112 The Ksplice kernel component has returned an error code that this version of
 113 ksplice-undo does not understand.
 114 END
 115                 "ok" => <<'END',
 116 Ksplice has aborted the undo operation for unknown reasons.
 117 Please consider reporting a bug to PACKAGE_BUGREPORT.
 118 END
 119 );
 120         $error = "UNKNOWN" if (!exists $errors{$error});
 121         print STDERR "\n$errors{$error}\n";
 122 }
 123
 124 =head1 NAME
 125
 126 ksplice-undo - Undo a Ksplice update that has been applied to the running kernel
 127
 128 =head1 SYNOPSIS
 129
 130 B<ksplice-undo> I<KSPLICE_ID>
 131
 132 =head1 DESCRIPTION
 133
 134 B<ksplice-undo> takes as input a Ksplice identification tag, as reported by
 135 L<ksplice-view(8)>, and it reverses that update within the running binary kernel.
 136
 137 =head1 OPTIONS
 138
 139 =over 8
 140
 141 =item B<--debug>
 142
 143 Reverses the update with debugging output enabled.  Recommended only for
 144 debugging.
 145
 146 =back
 147
 148 =head1 SEE ALSO
 149
 150 L<ksplice-create(8)>, L<ksplice-apply(8)>, L<ksplice-view(8)>
 151
 152 =head1 COPYRIGHT
 153
 154 Copyright (C) 2007-2008  Jeffrey Brian Arnold <jbarnold@mit.edu>
 155 Copyright (C) 2008  Anders Kaseorg <andersk@mit.edu>,
 156                     Tim Abbott <tabbott@mit.edu>
 157
 158 This is free software and documentation.  You can redistribute and/or modify it
 159 under the terms of the GNU General Public License, version 2.
 160
 161 =cut