package SocketActivation; # vim:ts=4:sw=4:expandtab use strict; use warnings; use IO::Socket::UNIX; # core use Cwd qw(abs_path); # core use POSIX qw(:fcntl_h); # core use AnyEvent::Handle; # not core use AnyEvent::Util; # not core use Exporter 'import'; use v5.10; our @EXPORT = qw(activate_i3); # # Starts i3 using socket activation. Creates a listening socket (with bind + # listen) which is then passed to i3, who in turn calls accept and handles the # requests. # # Since the kernel buffers the connect, the parent process can connect to the # socket immediately after forking. It then sends a request and waits until it # gets an answer. Obviously, i3 has to be initialized to actually answer the # request. # # This way, we can wait *precisely* the amount of time which i3 waits to get # ready, which is a *HUGE* speed gain (and a lot more robust) in comparison to # using sleep() with a fixed amount of time. # # unix_socket_path: Location of the socket to use for the activation # display: X11 $ENV{DISPLAY} # configfile: path to the configuration file to use # logpath: path to the logfile to which i3 will append # cv: an AnyEvent->condvar which will be triggered once i3 is ready # sub activate_i3 { my %args = @_; # remove the old unix socket unlink($args{unix_socket_path}); my $socket = IO::Socket::UNIX->new( Listen => 1, Local => $args{unix_socket_path}, ); my $pid = fork; if (!defined($pid)) { die "could not fork()"; } if ($pid == 0) { $ENV{LISTEN_PID} = $$; $ENV{LISTEN_FDS} = 1; delete $ENV{DESKTOP_STARTUP_ID}; delete $ENV{I3SOCK}; # $SHELL could be set to fish, which will horribly break running shell # commands via i3’s exec feature. This happened e.g. when having # “set-option -g default-shell "/usr/bin/fish"” in ~/.tmux.conf delete $ENV{SHELL}; unless ($args{dont_create_temp_dir}) { $ENV{XDG_RUNTIME_DIR} = '/tmp/i3-testsuite/'; mkdir $ENV{XDG_RUNTIME_DIR}; } $ENV{DISPLAY} = $args{display}; $ENV{PATH} = join(':', '../i3-nagbar', '../i3-msg', '../i3-config-wizard', '../i3bar', '..', $ENV{PATH} ); # We are about to exec, but we did not modify $^F to include $socket # when creating the socket (because the file descriptor could have a # number != 3 which would lead to i3 leaking a file descriptor). This # caused Perl to set the FD_CLOEXEC flag, which would close $socket on # exec(), effectively *NOT* passing $socket to the new process. # Therefore, we explicitly clear FD_CLOEXEC (the only flag right now) # by setting the flags to 0. POSIX::fcntl($socket, F_SETFD, 0) or die "Could not clear fd flags: $!"; # If the socket does not use file descriptor 3 by chance already, we # close fd 3 and dup2() the socket to 3. if (fileno($socket) != 3) { POSIX::close(3); POSIX::dup2(fileno($socket), 3); POSIX::close(fileno($socket)); } # Make sure no file descriptors are open. Strangely, I got an open file # descriptor pointing to AnyEvent/Impl/EV.pm when testing. AnyEvent::Util::close_all_fds_except(0, 1, 2, 3); # Construct the command to launch i3. Use maximum debug level, disable # the interactive signalhandler to make it crash immediately instead. # Also disable logging to SHM since we redirect the logs anyways. # Force Xinerama because we use Xdmx for multi-monitor tests. my $i3cmd = abs_path("../i3") . q| -V -d all --disable-signalhandler| . q| --shmlog-size=0 --force-xinerama|; # For convenience: my $outdir = $args{outdir}; my $test = $args{testname}; if ($args{restart}) { $i3cmd .= ' -L ' . abs_path('restart-state.golden'); } if ($args{valgrind}) { $i3cmd = qq|valgrind -v --log-file="$outdir/valgrind-for-$test.log" | . qq|--leak-check=full --track-origins=yes --num-callers=20 | . qq|--tool=memcheck -- $i3cmd|; } my $logfile = "$outdir/i3-log-for-$test"; # Append to $logfile instead of overwriting because i3 might be # run multiple times in one testcase. my $cmd = "exec $i3cmd -c $args{configfile} >>$logfile 2>&1"; if ($args{strace}) { my $out = "$outdir/strace-for-$test.log"; # We overwrite LISTEN_PID with the correct process ID to make # socket activation work (LISTEN_PID has to match getpid(), # otherwise the LISTEN_FDS will be treated as a left-over). $cmd = qq|strace -fF -s2048 -v -o "$out" -- | . 'sh -c "export LISTEN_PID=\$\$; ' . $cmd . '"'; } if ($args{xtrace}) { my $out = "$outdir/xtrace-for-$test.log"; # See comment in $args{strace} branch. $cmd = qq|xtrace -n -o "$out" -- | . 'sh -c "export LISTEN_PID=\$\$; ' . $cmd . '"'; } # We need to use the shell due to using output redirections. exec '/bin/sh', '-c', $cmd; # if we are still here, i3 could not be found or exec failed. bail out. exit 1; } # close the socket, the child process should be the only one which keeps a file # descriptor on the listening socket. $socket->close; # We now connect (will succeed immediately) and send a request afterwards. # As soon as the reply is there, i3 is considered ready. my $cl = IO::Socket::UNIX->new(Peer => $args{unix_socket_path}); my $hdl; $hdl = AnyEvent::Handle->new( fh => $cl, on_error => sub { $hdl->destroy; $args{cv}->send(0); }); # send a get_tree message without payload $hdl->push_write('i3-ipc' . pack("LL", 0, 4)); # wait for the reply $hdl->push_read(chunk => 1, => sub { my ($h, $line) = @_; $args{cv}->send(1); undef $hdl; }); return $pid; } 1