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