150 lines
3.9 KiB
Perl
Executable File
150 lines
3.9 KiB
Perl
Executable File
#!/usr/bin/perl -w
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# LiveJournal Remote Procedure Call Daemon (ljrpcd)
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# Copyright 2001 Dormando (dormando@rydia.net)
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# Going add a license (GPL?) later.
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# This daemon forks off into the background, logs if told to
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# waits for UDP messages on the given port, and executes
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# commands sent to it.
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#
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# <LJDEP>
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# lib: IO::Socket
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# prog: bin/ljmaint.pl
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# </LJDEP>
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use strict;
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use IO::Socket;
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# Max message length and port to bind.
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my $MAXLEN = 512;
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my $PORTNO = 6100;
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my $PIDFILE = '/var/run/ljrpcd.pid';
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my $LOGFILE = '/var/log/ljrpcd.log';
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my $TYPE = shift @ARGV;
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unless ($TYPE eq "web" || $TYPE eq "db") {
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print "Unknown/unspecified machine type, quitting.\n";
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exit 1;
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}
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# Pid and pidfile.
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my $pid;
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my $is_parent = 1;
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# Socket. Needs to be here for the HUP stuff.
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my $sock;
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# In case we're shot, unlink the pidfile.
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$SIG{TERM} = sub {
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unlink($PIDFILE);
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exit 1;
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};
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if (-e $PIDFILE) {
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open (PID, $PIDFILE);
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my $tpid;
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chomp ($tpid = <PID>);
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close PID;
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if ($tpid) {
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# so Linux-specific, but Proc::ProcessTable
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#iterates over /dev forever, which sucks on a NetApp
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if (open (CMD, "/proc/$tpid/cmdline")) {
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my $cmdline = <CMD>;
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close CMD;
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if ($cmdline =~ /ljrpcd/) {
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print "Process exists already, quitting.\n";
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exit 1;
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}
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}
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}
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}
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# Print a banner.
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print "LiveJournal RPC Daemon starting up into the background...\n";
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# Perhaps I should give it a command to not do this in the future.
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if ($pid = fork) {
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# Parent, log pid and exit.
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open(PID, ">$PIDFILE") or die "Couldn't open $PIDFILE for writing: $!\n";
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print PID $pid;
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close(PID);
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print "Closing ($pid) wrote to $PIDFILE\n";
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$is_parent = 1;
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exit;
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} else {
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# This is the child, main loop-de-doo.
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my($cmdmsg, $remaddr, $remhost);
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# HUP signal handler.
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$SIG{HUP} = \&restart_request;
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open(LOG, ">>$LOGFILE") or die "Couldn't open log file for appending: $!\n";
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flock(LOG, 2) or die "Couldn't flock log file for writing: $!\n";
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select(LOG); # Why the hell not, eh?
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$| = 1;
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$sock = IO::Socket::INET->new(LocalPort => "$PORTNO", Proto => 'udp') or die "socket: $@";
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$sock->sockopt(SO_BROADCAST, 1);
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print "Bound, awaiting UDP commands on port $PORTNO\n";
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# Main loop, simple parser.
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while ($sock->recv($cmdmsg, $MAXLEN)) {
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my ($port, $ipaddr) = sockaddr_in($sock->peername);
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my $ip_addy = inet_ntoa($ipaddr);
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$remhost = gethostbyaddr($ipaddr, AF_INET);
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print "Client $remhost sent command: $cmdmsg\n";
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# If the command is 'marco' return 'pollo'
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if ($cmdmsg =~ /^marco(\s+($TYPE|all))?$/) {
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print "Returning 'pollo' to client $remhost\n";
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$sock->send("pollo") or print "Couldn't scream pollo at $remhost\n";
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next;
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} elsif ($cmdmsg =~ s/^cmd:\s//) {
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# Handle the command.
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if ($cmdmsg eq "restart") {
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print "Restarting ljrpcd\n";
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$sock->send("Restarting ljrpcd...\n");
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restart_request();
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}
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my $return = handle_request($cmdmsg);
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print "Returning $return to client $remhost\n";
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$sock->send($return) or print "Couldn't return $return to $remhost\n";
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next;
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}
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}
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die "recv: $!\n";
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} #if
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# Sub to restart the daemon.
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sub restart_request {
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$sock->close;
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unlink($PIDFILE);
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exec($0, $TYPE);
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}
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# Handle a request... Do further parsing, pass it appropriately.
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# Should return a discernable ok. Usually 'done' 'ok' or an
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# informative reply no longer than 500 characters.
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sub handle_request {
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my $cmd = shift;
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my $su = "";
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if ($cmd =~ s/^(\w+?)://) {
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my $user = $1;
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my ($login,$pass,$uid,$gid) = getpwnam($user)
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or return "$user not in passwd file.";
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$su = "su $user -c";
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}
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unless ($cmd =~ /[\|\>\<]/) {
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my $home = $ENV{'LJHOME'} || "/home/lj";
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$cmd =~ s/[;]/\\$&/;
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if ($su) {
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return `$su \'$home/bin/ljmaint.pl $cmd\'`;
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} else {
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return `$home/bin/ljmaint.pl $cmd`;
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}
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}
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return 'bad command';
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}
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