52 lines
1.4 KiB
Perl
52 lines
1.4 KiB
Perl
use strict;
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use File::Temp qw(tempdir);
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our @sshOpts = split ' ', ($ENV{"NIX_SSHOPTS"} or "");
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push @sshOpts, "-x";
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my $sshStarted = 0;
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my $sshHost;
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# Open a master SSH connection to `host', unless there already is a
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# running master connection (as determined by `-O check').
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sub openSSHConnection {
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my ($host) = @_;
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die if $sshStarted;
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$sshHost = $host;
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return 1 if system("ssh $sshHost @sshOpts -O check 2> /dev/null") == 0;
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my $tmpDir = tempdir("nix-ssh.XXXXXX", CLEANUP => 1, TMPDIR => 1)
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or die "cannot create a temporary directory";
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push @sshOpts, "-S", "$tmpDir/control";
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# Start the master. We can't use the `-f' flag (fork into
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# background after establishing the connection) because then the
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# child continues to run if we are killed. So instead make SSH
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# print "started" when it has established the connection, and wait
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# until we see that.
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open SSHPIPE, "ssh $sshHost @sshOpts -M -N -o LocalCommand='echo started' -o PermitLocalCommand=yes |" or die;
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while (<SSHPIPE>) {
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chomp;
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if ($_ eq "started") {
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$sshStarted = 1;
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return 1;
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}
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}
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return 0;
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}
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# Tell the master SSH client to exit.
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sub closeSSHConnection {
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if ($sshStarted) {
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system("ssh $sshHost @sshOpts -O exit 2> /dev/null") == 0
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or warn "unable to stop SSH master: $?";
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}
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}
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END { my $saved = $?; closeSSHConnection; $? = $saved; }
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return 1;
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