mirror of
https://github.com/NixOS/nix.git
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111 lines
2.3 KiB
Perl
111 lines
2.3 KiB
Perl
package Nix::SSH;
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use utf8;
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use strict;
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use File::Temp qw(tempdir);
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use IPC::Open2;
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our @ISA = qw(Exporter);
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our @EXPORT = qw(
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@globalSshOpts
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readN readInt readString readStrings
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writeInt writeString writeStrings
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connectToRemoteNix
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);
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our @globalSshOpts = split ' ', ($ENV{"NIX_SSHOPTS"} or "");
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sub readN {
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my ($bytes, $from) = @_;
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my $res = "";
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while ($bytes > 0) {
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my $s;
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my $n = sysread($from, $s, $bytes);
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die "I/O error reading from remote side\n" if !defined $n;
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die "got EOF while expecting $bytes bytes from remote side\n" if !$n;
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$bytes -= $n;
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$res .= $s;
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}
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return $res;
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}
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sub readInt {
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my ($from) = @_;
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return unpack("L<x4", readN(8, $from));
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}
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sub readString {
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my ($from) = @_;
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my $len = readInt($from);
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my $s = readN($len, $from);
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readN(8 - $len % 8, $from) if $len % 8; # skip padding
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return $s;
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}
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sub readStrings {
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my ($from) = @_;
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my $n = readInt($from);
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my @res;
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push @res, readString($from) while $n--;
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return @res;
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}
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sub writeInt {
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my ($n, $to) = @_;
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syswrite($to, pack("L<x4", $n)) or die;
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}
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sub writeString {
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my ($s, $to) = @_;
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my $len = length $s;
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my $req .= pack("L<x4", $len);
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$req .= $s;
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$req .= "\000" x (8 - $len % 8) if $len % 8;
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syswrite($to, $req) or die;
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}
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sub writeStrings {
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my ($ss, $to) = @_;
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writeInt(scalar(@{$ss}), $to);
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writeString($_, $to) foreach @{$ss};
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}
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sub connectToRemoteNix {
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my ($sshHost, $sshOpts, $extraFlags) = @_;
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$extraFlags ||= "";
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# Start ‘nix-store --serve’ on the remote host.
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my ($from, $to);
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# FIXME: don't start a shell, start ssh directly.
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my $pid = open2($from, $to, "exec ssh -x -a $sshHost @globalSshOpts @{$sshOpts} nix-store --serve --write $extraFlags");
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# Do the handshake.
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my $magic;
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eval {
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my $SERVE_MAGIC_1 = 0x390c9deb; # FIXME
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my $clientVersion = 0x200;
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syswrite($to, pack("L<x4L<x4", $SERVE_MAGIC_1, $clientVersion)) or die;
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$magic = readInt($from);
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};
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die "unable to connect to '$sshHost'\n" if $@;
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die "did not get valid handshake from remote host\n" if $magic != 0x5452eecb;
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my $serverVersion = readInt($from);
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die "unsupported server version\n" if $serverVersion < 0x200 || $serverVersion >= 0x300;
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return ($from, $to, $pid);
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}
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1;
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