ksplice-undo.in

   1 #!/usr/bin/perl
   2
   3 # Copyright (C) 2007-2009  Ksplice, Inc.
   4 # Authors: Jeff Arnold, Anders Kaseorg, Tim Abbott
   5 #
   6 # This program is free software; you can redistribute it and/or modify
   7 # it under the terms of the GNU General Public License, version 2.
   8 #
   9 # This program is distributed in the hope that it will be useful,
  10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 # GNU General Public License for more details.
  13 #
  14 # You should have received a copy of the GNU General Public License
  15 # along with this program; if not, write to the Free Software
  16 # Foundation, Inc., 51 Franklin Street - Fifth Floor, Boston, MA
  17 # 02110-1301, USA.
  18
  19 use strict;
  20 use warnings;
  21 use lib 'KSPLICE_DATA_DIR';
  22 use Ksplice;
  23 my $have_usleep = eval { require Time::HiRes };
  24
  25 my $debug;
  26 my $debugon = 0;
  27 GetOptions(@common_options,
  28         "debug" => \$debugon,
  29         "debugfile=s" => \$debug) or pod2usage(1);
  30
  31 pod2usage(1) if($help || scalar(@ARGV) != 1);
  32 $debugon = 1 if (defined($debug));
  33 $debug = abs_path($debug) if (defined $debug);
  34
  35 my $kid = $ARGV[0];
  36 $kid =~ s/^ksplice[-_]//;
  37 $kid =~ s/[-_].*$//;
  38 my $update = "ksplice_$kid";
  39 my $nounload = runstr("lsmod") =~ m/- $/m;
  40
  41 chdir("/sys/module");
  42
  43 if (!update_loaded($kid)
  44     && !-e $update && !defined(glob("${update}_*_{old,new}"))) {
  45         print "Ksplice id $kid is not present in the kernel\n";
  46         exit(1);
  47 }
  48 my $have_sysfs = update_loaded($kid);
  49
  50 set_debug_level($kid, $debugon);
  51 my $failed = 0;
  52
  53 foreach my $module (glob("${update}_*_old")) {
  54         if (!$nounload && runval_raw('rmmod', $module) != 0) {
  55                 child_error();
  56                 error_die();
  57         }
  58 }
  59
  60 my $stage = ($have_sysfs && get_stage($kid));
  61 if ($stage ne 'applied') {
  62         print "Ksplice id $kid is not applied; just cleaning up\n";
  63 }
  64 else {
  65         set_stage($kid, "reversed");
  66 }
  67 $stage = ($have_sysfs && get_stage($kid));
  68 ($stage eq 'reversed') or !$have_sysfs or error_die();
  69
  70 foreach my $module (glob("${update}_*_new")) {
  71         if (!$nounload && runval_raw('rmmod', $module) != 0) {
  72                 child_error();
  73                 error_die();
  74         }
  75 }
  76
  77 set_stage($kid, "cleanup") if ($have_sysfs);
  78 if ($have_usleep) {
  79         my $count = 0;
  80         while (update_loaded($kid) && $count < 5) {
  81                 Time::HiRes::usleep(100000);
  82                 $count++;
  83         }
  84 } else {
  85         sleep(1) if (!update_loaded($kid));
  86 }
  87 if (-e "/sys/module/$update") {
  88         if (!$nounload && runval_raw('rmmod', $update) != 0) {
  89                 child_error();
  90                 error_die();
  91         }
  92 }
  93
  94 rmtree("/var/run/ksplice/updates/$kid") if (-e "/var/run/ksplice/updates/$kid");
  95
  96 exit(0);
  97
  98 sub error_die {
  99         if (!update_loaded($kid)) {
 100                 print STDERR "Error undoing Ksplice update $kid\n";
 101                 die;
 102         }
 103         my $debugfile = get_debug_output($kid, $debug);
 104         print STDERR "Error undoing Ksplice update $kid:\n";
 105         my $abort_cause = get_abort_cause($kid);
 106         my $conflicts = get_conflicts($kid);
 107         print_error($abort_cause);
 108         if ($abort_cause eq 'code_busy') {
 109                 print $conflicts;
 110         }
 111         if($debugon && defined $debugfile) {
 112                 print("Debugging output saved to $debugfile\n");
 113         }
 114         die;
 115 }
 116
 117 sub print_error {
 118         my ($error) = @_;
 119         my %errors = (
 120                 "code_busy" => <<'END',
 121 Ksplice has aborted the undo operation because it appears that the code that
 122 you are trying to change is continuously in use by the system.  More
 123 specifically, Ksplice has been unable to find a moment when one or more of the
 124 to-be-changed functions is not on a thread's kernel stack.
 125 END
 126                 "module_busy" => <<'END',
 127 Ksplice has aborted the undo operation because it appears that the Ksplice
 128 update that you are trying to unload is in use by another module.  You can find
 129 out what module is using the Ksplice update using the lsmod command.
 130 END
 131                 "unexpected_running_task" => <<'END',
 132 Ksplice has aborted the undo operation because of an unexpected failure during
 133 the kernel stack check.  Please consider reporting a bug to PACKAGE_BUGREPORT.
 134 END
 135                 "out_of_memory" => <<'END',
 136 Ksplice has aborted the undo operation because the kernel ran out of memory.
 137 END
 138                 "call_failed" => <<'END',
 139 Ksplice has aborted the undo operation at the request of a one of the
 140 pre-application hooks that were included as part of this Ksplice
 141 update.  This is likely the result of a bug in the patch used to
 142 generate this update.
 143 END
 144                 "cold_update_loaded" => <<'END',
 145 Ksplice has aborted the undo operation because the update was applied using the
 146 --partial option, and one of the modules that was changed by the update was loaded
 147 since the update was applied.  You must first unload that (cold patched) module
 148 before you can undo this update.
 149 END
 150                 "unexpected" => <<'END',
 151 Ksplice has aborted because of an unexpected error.
 152 Please consider reporting a bug to PACKAGE_BUGREPORT.
 153 END
 154                 "UNKNOWN" => <<'END',
 155 The Ksplice kernel component has returned an error code that this version of
 156 ksplice-undo does not understand.
 157 END
 158                 "ok" => <<'END',
 159 Ksplice has aborted the undo operation for unknown reasons.
 160 Please consider reporting a bug to PACKAGE_BUGREPORT.
 161 END
 162 );
 163         $error = "UNKNOWN" if (!exists $errors{$error});
 164         print STDERR "\n$errors{$error}\n";
 165 }
 166
 167 =head1 NAME
 168
 169 ksplice-undo - Undo a Ksplice update that has been applied to the running kernel
 170
 171 =head1 SYNOPSIS
 172
 173 B<ksplice-undo> [I<OPTIONS>] I<KSPLICE_ID>
 174
 175 =head1 DESCRIPTION
 176
 177 B<ksplice-undo> takes as input a Ksplice identification tag, as reported by
 178 L<ksplice-view(8)>, and it reverses that update within the running binary kernel.
 179
 180 =head1 OPTIONS
 181
 182 =over 8
 183
 184 =item B<--debug>
 185
 186 Reverses the update with debugging output enabled.  Recommended only for
 187 debugging.
 188
 189 =item B<--debugfile=>I<filename>
 190
 191 Sets the location where debugging output should be saved.  Implies --debug.
 192
 193 =back
 194
 195 =head1 SEE ALSO
 196
 197 L<ksplice-create(8)>, L<ksplice-apply(8)>, L<ksplice-view(8)>
 198
 199 =head1 BUGS
 200
 201 Please report bugs to <PACKAGE_BUGREPORT>.
 202
 203 =head1 AUTHORS
 204
 205 Jeff Arnold, Anders Kaseorg, and Tim Abbott
 206
 207 =head1 COPYRIGHT
 208
 209 Copyright (C) 2007-2009  Ksplice, Inc.
 210
 211 This is free software and documentation.  You can redistribute and/or modify it
 212 under the terms of the GNU General Public License, version 2.
 213
 214 =cut