mdw@git.distorted.org.uk Git - distorted-backup/blob - snap.rfreezefs.in

   1 #! @PERL@
   2 ###
   3 ### Synchronize snapshot with remotely mounted filesystem
   4 ###
   5 ### (c) 2011 Mark Wooding
   6 ###
   7
   8 ###----- Licensing notice ---------------------------------------------------
   9 ###
  10 ### This file is part of the distorted.org.uk backup suite.
  11 ###
  12 ### distorted-backup is free software; you can redistribute it and/or modify
  13 ### it under the terms of the GNU General Public License as published by
  14 ### the Free Software Foundation; either version 2 of the License, or
  15 ### (at your option) any later version.
  16 ###
  17 ### distorted-backup is distributed in the hope that it will be useful,
  18 ### but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 ### MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20 ### GNU General Public License for more details.
  21 ###
  22 ### You should have received a copy of the GNU General Public License along
  23 ### with distorted-backup; if not, write to the Free Software Foundation,
  24 ### Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  25
  26 use Socket;
  27
  28 ###--------------------------------------------------------------------------
  29 ### Utilities.
  30
  31 (our $QUIS = $0) =~ s:^.*/::;
  32 sub whine ($) { my ($msg) = @_; print STDERR "$QUIS: $msg\n"; }
  33 sub fail ($) { my ($msg) = @_; whine $msg; exit $! || ($? >> 8) || 255; }
  34
  35 our @CLEANUP = ();
  36 sub cleanup (&) { my ($func) = @_; unshift @CLEAUP, $func; }
  37 END { local $?; for my $func (@CLEANUP) { &$func } }
  38
  39 sub gripelist ($@) {
  40   my ($gripe, @things) = @_;
  41   fail "$gripe: " . join(", ", @things) if @things;
  42 }
  43
  44 ###--------------------------------------------------------------------------
  45 ### Parse command line.
  46
  47 our $USAGE = "usage: $QUIS DEVICE [KEY=VALUE ...]";
  48 sub version { print "$QUIS, version 1.0.0\n"; }
  49 sub help {
  50   print <<EOF;
  51 $USAGE
  52
  53 Option keys:
  54   dir=MOUNTPT           Mount point of filesystem on remote host [required].
  55   host=[USER@]NAME      Name or address of remote host [required].
  56   op=OPERATION          `snap' to create snapshot, or `unsnap' to remove.
  57   rfreezefs=PATH        Location of `rfreezefs' program on remote host.
  58   ssh=PATH              Location of remote-shell program on local host.
  59   subtype=TYPE          Type of snapshot to create [required].
  60
  61 Other option keys are passed to the underlying snapshot TYPE.
  62 EOF
  63 }
  64 @ARGV >= 1 or do { print STDERR $USAGE, "\n"; exit 1; };
  65 $ARGV[0] eq "-v" || $ARGV[0] eq "--version" and do { version; exit; };
  66 $ARGV[0] eq "-h" || $ARGV[0] eq "--help" and do { version; help; exit; };
  67
  68 our $DEV = shift;
  69 our %OPT = ( dir => undef,
  70              host => undef,
  71              op => "snap",
  72              rfreezefs => "rfreezefs",
  73              ssh => "ssh",
  74              subtype => undef );
  75 our @PASS = ();
  76
  77 for my $i (@ARGV) {
  78   $i =~ /^([^\s=]+)=(.*)$/ or fail "malformed option `$i'";
  79   my ($k, $v) = ($1, $2);
  80   if ($k =~ /^([^.]+)\.(.+)$/) {
  81     if ($2 eq "rfreezefs") { $k = $1; }
  82   }
  83   if (exists $OPT{$k}) { $OPT{$k} = $v; }
  84   else { push @PASS, $i; }
  85 }
  86 gripelist "missing arguments", grep { !defined $OPT{$_} } keys %OPT;
  87
  88 (my $host = $OPT{host}) =~ s/^.*@//;
  89 my $addr = inet_aton $host or fail "failed to resolve `$OPT{host}'";
  90
  91 ###--------------------------------------------------------------------------
  92 ### Remove a snapshot if requested.
  93
  94 if ($OPT{op} eq "unsnap") {
  95
  96   ## This doesn't require negotiation with the remote end.
  97   if ($OPT{unsnap}) {
  98     exec "snap.$OPT{subtype}", $DEV, "op=unsnap", @PASS;
  99     fail "exec snap.$OPT{subtype}: $!";
 100   }
 101
 102 } elsif ($OPT{op} ne "snap") {
 103   fail "unknown operation `$OPT{op}'";
 104 }
 105
 106 ###--------------------------------------------------------------------------
 107 ### Run `rfreezefs' on the remote host and collect information.
 108
 109 (my $dir = $OPT{dir}) =~ s/\'/'\\''/g;
 110 open SSH, "-|", $OPT{ssh}, $OPT{host}, "$OPT{rfreezefs} -n '$dir'"
 111   or fail "open(ssh): $!";
 112 cleanup { close SSH };
 113
 114 our %INF = ( PORT => undef );
 115 our %TOK = ();
 116 our %RTOK = ();
 117 our $PORT = undef;
 118
 119 while (<SSH>) {
 120   my @f = split;
 121   if ($f[0] eq "PORT") { $INF{$f[0]} = $f[1]; }
 122   elsif ($f[1] eq "TOKEN") { $TOK{$f[1]} = $f[2]; $RTOK{$f[2]} = $f[1]; }
 123   elsif ($f[0] eq "READY") { last; }
 124 }
 125
 126 gripelist "missing information", grep { !defined $INF{$_} } keys %INF;
 127 gripelist "missing tokens",
 128   grep { !exists $TOK{$_} } "FREEZE", "FROZEN", "THAW", "THAWED";
 129
 130 ###--------------------------------------------------------------------------
 131 ### Create the snapshot.
 132
 133 ## Connect to the socket.
 134 socket SK, PF_INET, SOCK_STREAM, 0 or fail "socket: $!";
 135 cleanup { close SK };
 136 select SK; $| = 1;
 137 connect SK, sockaddr_in($INF{PORT}, $addr) or fail "connect: $!";
 138
 139 ## Communication with the server.
 140 sub rffscmd ($;$) {
 141   my ($cmd, $rpl) = @_;
 142   print SK $TOK{$cmd}, "\n" or fail "write <$cmd>: $!";
 143   if ($rpl) {
 144     chomp (my $line = <SK>);
 145     if ($line ne $TOK{$rpl}) {
 146       my $what = exists $RTOK{$line} ? "<$RTOK{$line}>" : "`$line'";
 147       fail "unexpected response $what to <$cmd>";
 148     }
 149   }
 150 }
 151
 152 ## Freeze the remote filesystem.
 153 rffscmd(FREEZE, FROZEN);
 154
 155 ## Create the snapshot locally using the appropriate mechanism.  This will
 156 ## print the snapshot device name.
 157 my $rc = system "snap.$OPT{subtype}", $DEV, @PASS;
 158 $rc and fail "snap.$OPT{subtype} failed (rc = $rc)";
 159
 160 ## Discard the snapshot again if anything goes wrong.
 161 cleanup {
 162   if ($?) {
 163     my $rc = system "snap.$OPT{subtype}", $DEV, "unsnap", @PASS;
 164     $rc and
 165       whine "snap.$OPT{subtype} failed to unsnap (rc = $rc) " .
 166         "while recovering";
 167   }
 168 };
 169
 170 ## Thaw the remote filesystem.
 171 rffscmd(THAW, THAWED);
 172
 173 ###----- That's all, folks --------------------------------------------------
 174
 175 exit 0;