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 $kid is not present in the kernel\n";
  46         rmtree("/var/run/ksplice/updates/$kid") if (-e "/var/run/ksplice/updates/$kid");
  47         exit(1);
  48 }
  49 my $have_sysfs = update_loaded($kid);
  50
  51 set_debug_level($kid, $debugon);
  52 my $failed = 0;
  53
  54 foreach my $module (glob("${update}_*_old")) {
  55         if (!$nounload && runval_raw('rmmod', $module) != 0) {
  56                 child_error();
  57                 error_die();
  58         }
  59 }
  60
  61 my $stage = ($have_sysfs && get_stage($kid));
  62 if ($stage ne 'applied') {
  63         print "Ksplice id $kid is not applied; just cleaning up\n";
  64 }
  65 else {
  66         set_stage($kid, "reversed");
  67 }
  68 $stage = ($have_sysfs && get_stage($kid));
  69 ($stage eq 'reversed') or !$have_sysfs or error_die();
  70
  71 foreach my $module (glob("${update}_*_new")) {
  72         if (!$nounload && runval_raw('rmmod', $module) != 0) {
  73                 child_error();
  74                 error_die();
  75         }
  76 }
  77
  78 set_stage($kid, "cleanup") if ($have_sysfs);
  79 if ($have_usleep) {
  80         my $count = 0;
  81         while (update_loaded($kid) && $count < 5) {
  82                 Time::HiRes::usleep(100000);
  83                 $count++;
  84         }
  85 } else {
  86         sleep(1) if (!update_loaded($kid));
  87 }
  88 if (-e "/sys/module/$update") {
  89         if (!$nounload && runval_raw('rmmod', $update) != 0) {
  90                 child_error();
  91                 error_die();
  92         }
  93 }
  94
  95 rmtree("/var/run/ksplice/updates/$kid") if (-e "/var/run/ksplice/updates/$kid");
  96
  97 exit(0);
  98
  99 sub error_die {
 100         if (!update_loaded($kid)) {
 101                 print STDERR "Error undoing Ksplice update $kid\n";
 102                 die;
 103         }
 104         my $debugfile = get_debug_output($kid, $debug);
 105         print STDERR "Error undoing Ksplice update $kid:\n";
 106         my $abort_cause = get_abort_cause($kid);
 107         my $conflicts = get_conflicts($kid);
 108         print_error($abort_cause);
 109         if ($abort_cause eq 'code_busy') {
 110                 print $conflicts;
 111         }
 112         if($debugon && defined $debugfile) {
 113                 print("Debugging output saved to $debugfile\n");
 114         }
 115         die;
 116 }
 117
 118 sub print_error {
 119         my ($error) = @_;
 120         my %errors = (
 121                 "code_busy" => <<'END',
 122 Ksplice has aborted the undo operation because it appears that the code that
 123 you are trying to change is continuously in use by the system.  More
 124 specifically, Ksplice has been unable to find a moment when one or more of the
 125 to-be-changed functions is not on a thread's kernel stack.
 126 END
 127                 "module_busy" => <<'END',
 128 Ksplice has aborted the undo operation because it appears that the Ksplice
 129 update that you are trying to unload is in use by another module.  You can find
 130 out what module is using the Ksplice update using the lsmod command.
 131 END
 132                 "unexpected_running_task" => <<'END',
 133 Ksplice has aborted the undo operation because of an unexpected failure during
 134 the kernel stack check.  Please consider reporting a bug to PACKAGE_BUGREPORT.
 135 END
 136                 "out_of_memory" => <<'END',
 137 Ksplice has aborted the undo operation because the kernel ran out of memory.
 138 END
 139                 "call_failed" => <<'END',
 140 Ksplice has aborted the undo operation at the request of a one of the
 141 pre-application hooks that were included as part of this Ksplice
 142 update.  This is likely the result of a bug in the patch used to
 143 generate this update.
 144 END
 145                 "cold_update_loaded" => <<'END',
 146 Ksplice has aborted the undo operation because the update was applied using the
 147 --partial option, and one of the modules that was changed by the update was loaded
 148 since the update was applied.  You must first unload that (cold patched) module
 149 before you can undo this update.
 150 END
 151                 "unexpected" => <<'END',
 152 Ksplice has aborted because of an unexpected error.
 153 Please consider reporting a bug to PACKAGE_BUGREPORT.
 154 END
 155                 "UNKNOWN" => <<'END',
 156 The Ksplice kernel component has returned an error code that this version of
 157 ksplice-undo does not understand.
 158 END
 159                 "ok" => <<'END',
 160 Ksplice has aborted the undo operation for unknown reasons.
 161 Please consider reporting a bug to PACKAGE_BUGREPORT.
 162 END
 163 );
 164         $error = "UNKNOWN" if (!exists $errors{$error});
 165         print STDERR "\n$errors{$error}\n";
 166 }
 167
 168 =head1 NAME
 169
 170 ksplice-undo - Undo a Ksplice update that has been applied to the running kernel
 171
 172 =head1 SYNOPSIS
 173
 174 B<ksplice-undo> [I<OPTIONS>] I<KSPLICE_ID>
 175
 176 =head1 DESCRIPTION
 177
 178 B<ksplice-undo> takes as input a Ksplice identification tag, as reported by
 179 L<ksplice-view(8)>, and it reverses that update within the running binary kernel.
 180
 181 =head1 OPTIONS
 182
 183 =over 8
 184
 185 =item B<--debug>
 186
 187 Reverses the update with debugging output enabled.  Recommended only for
 188 debugging.
 189
 190 =item B<--debugfile=>I<filename>
 191
 192 Sets the location where debugging output should be saved.  Implies --debug.
 193
 194 =back
 195
 196 =head1 SEE ALSO
 197
 198 L<ksplice-create(8)>, L<ksplice-apply(8)>, L<ksplice-view(8)>
 199
 200 =head1 BUGS
 201
 202 Please report bugs to <PACKAGE_BUGREPORT>.
 203
 204 =head1 AUTHORS
 205
 206 Jeff Arnold, Anders Kaseorg, and Tim Abbott
 207
 208 =head1 COPYRIGHT
 209
 210 Copyright (C) 2007-2009  Ksplice, Inc.
 211
 212 This is free software and documentation.  You can redistribute and/or modify it
 213 under the terms of the GNU General Public License, version 2.
 214
 215 =cut