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 $debug = 0;
  26 GetOptions(@common_options,
  27         "debug" => \$debug) or pod2usage(1);
  28
  29 pod2usage(1) if($help || scalar(@ARGV) != 1);
  30
  31 my $kid = $ARGV[0];
  32 $kid =~ s/^ksplice[-_]//;
  33 $kid =~ s/[-_].*$//;
  34 my $update = "ksplice_$kid";
  35 my $nounload = runstr("lsmod") =~ m/- $/m;
  36
  37 if (!update_loaded($kid)) {
  38         print "Ksplice id $kid is not present in the kernel\n";
  39         exit(1);
  40 }
  41
  42 chdir("/sys/module/");
  43 set_debug_level($kid, $debug) if(defined($debug));
  44 my $stage = get_stage($kid);
  45 if ($stage ne 'applied') {
  46         print "Ksplice id $kid is not applied\n";
  47 }
  48 else {
  49         set_stage($kid, "reversed");
  50 }
  51
  52 my $failed = 0;
  53 foreach my $module (glob("${update}_*")) {
  54         if (!$nounload && runval_raw('rmmod', $module) != 0) {
  55                 child_error();
  56                 $failed = 1;
  57         }
  58 }
  59 if ($failed == 0 && -e "/sys/module/$update") {
  60         if (!$nounload && runval_raw('rmmod', $update) != 0) {
  61                 child_error();
  62                 $failed = 1;
  63         }
  64 }
  65 unless($failed == 0) {
  66         my ($debugfile, $debugout) = get_debug_output($kid);
  67         print STDERR "Error undoing Ksplice update $kid:\n";
  68         print $debugout;
  69         my $abort_cause = get_abort_cause($kid);
  70         my $conflicts = get_conflicts($kid);
  71         print_error($abort_cause);
  72         if ($abort_cause eq 'code_busy') {
  73                 print $conflicts;
  74         }
  75         if(defined $debugfile) {
  76                 print $debugout;
  77                 print("Debugging output saved to $debugfile\n");
  78         }
  79         die;
  80 }
  81 exit(0);
  82
  83 sub print_error {
  84         my ($error) = @_;
  85         my %errors = (
  86                 "code_busy" => <<'END',
  87 Ksplice has aborted the undo operation because it appears that the code that
  88 you are trying to change is continuously in use by the system.  More
  89 specifically, Ksplice has been unable to find a moment when one or more of the
  90 to-be-changed functions is not on a thread's kernel stack.
  91 END
  92                 "module_busy" => <<'END',
  93 Ksplice has aborted the undo operation because it appears that the Ksplice
  94 update that you are trying to unload is in use by another module.  You can find
  95 out what module is using the Ksplice update using the lsmod command.
  96 END
  97                 "unexpected_running_task" => <<'END',
  98 Ksplice has aborted the undo operation because of an unexpected failure during
  99 the kernel stack check.  Please consider reporting a bug to PACKAGE_BUGREPORT.
 100 END
 101                 "out_of_memory" => <<'END',
 102 Ksplice has aborted the undo operation because the kernel ran out of memory.
 103 END
 104                 "unexpected" => <<'END',
 105 Ksplice has aborted because of an unexpected error.
 106 Please consider reporting a bug to PACKAGE_BUGREPORT.
 107 END
 108                 "UNKNOWN" => <<'END',
 109 The Ksplice kernel component has returned an error code that this version of
 110 ksplice-undo does not understand.
 111 END
 112                 "ok" => <<'END',
 113 Ksplice has aborted the undo operation for unknown reasons.
 114 Please consider reporting a bug to PACKAGE_BUGREPORT.
 115 END
 116 );
 117         $error = "UNKNOWN" if (!exists $errors{$error});
 118         print STDERR "\n$errors{$error}\n";
 119 }
 120
 121 =head1 NAME
 122
 123 ksplice-undo - Undo a Ksplice update that has been applied to the running kernel
 124
 125 =head1 SYNOPSIS
 126
 127 B<ksplice-undo> I<KSPLICE_ID>
 128
 129 =head1 DESCRIPTION
 130
 131 B<ksplice-undo> takes as input a Ksplice identification tag, as reported by
 132 L<ksplice-view(8)>, and it reverses that update within the running binary kernel.
 133
 134 =head1 OPTIONS
 135
 136 =over 8
 137
 138 =item B<--debug>
 139
 140 Reverses the update with debugging output enabled.  Recommended only for
 141 debugging.
 142
 143 =back
 144
 145 =head1 SEE ALSO
 146
 147 L<ksplice-create(8)>, L<ksplice-apply(8)>, L<ksplice-view(8)>
 148
 149 =head1 COPYRIGHT
 150
 151 Copyright (C) 2007-2008  Jeffrey Brian Arnold <jbarnold@mit.edu>
 152 Copyright (C) 2008  Anders Kaseorg <andersk@mit.edu>,
 153                     Tim Abbott <tabbott@mit.edu>
 154
 155 This is free software and documentation.  You can redistribute and/or modify it
 156 under the terms of the GNU General Public License, version 2.
 157
 158 =cut