script/lei: background ourselves on MUA/pager exec

[public-inbox.git] / script / lei

diff --git a/script/lei b/script/lei
index 8dcea56290d8d35fa0550e3b190fa632cdac1259..bea8dcde97ea1be5662f4a02803137ca981bafbb 100755 (executable)
--- a/script/lei
+++ b/script/lei
@@ -4,10 +4,9 @@
 use strict;
 use v5.10.1;
 use Socket qw(AF_UNIX SOCK_SEQPACKET MSG_EOR pack_sockaddr_un);
-use Errno qw(EINTR ECONNRESET);
 use PublicInbox::CmdIPC4;
 my $narg = 5;
-my ($sock, $pwd);
+my $sock;
 my $recv_cmd = PublicInbox::CmdIPC4->can('recv_cmd4');
 my $send_cmd = PublicInbox::CmdIPC4->can('send_cmd4') // do {
        require PublicInbox::Spawn; # takes ~50ms even if built *sigh*
@@ -15,34 +14,32 @@ my $send_cmd = PublicInbox::CmdIPC4->can('send_cmd4') // do {
        PublicInbox::Spawn->can('send_cmd4');
 };
 
-sub sigchld {
-       my ($sig) = @_;
-       my $flags = $sig ? POSIX::WNOHANG() : 0;
-       while (waitpid(-1, $flags) > 0) {}
-}
-
-sub exec_cmd {
+my @orig_pid;
+my $exec_cmd = sub {
        my ($fds, $argc, @argv) = @_;
-       my @m = (*STDIN{IO}, '<&=',  *STDOUT{IO}, '>&=', *STDERR{IO}, '>&=');
+       die "BUG: already exec-ed\n" if @orig_pid;
+       @orig_pid = ($$);
+       require POSIX; # WNOHANG
+       my @old = (*STDIN{IO}, *STDOUT{IO}, *STDERR{IO});
        my @rdr;
        for my $fd (@$fds) {
-               my ($old_io, $mode) = splice(@m, 0, 2);
-               open(my $tmpfh, $mode, $fd) or die "open $mode$fd: $!";
-               push @rdr, $old_io, $mode, $tmpfh;
+               open(my $tmpfh, '+<&=', $fd) or die "open +<&=$fd: $!";
+               push @rdr, shift(@old), $tmpfh;
        }
-       require POSIX; # WNOHANG
-       $SIG{CHLD} = \&sigchld;
        my $pid = fork // die "fork: $!";
        if ($pid == 0) {
-               my %env = map { split(/=/, $_, 2) } splice(@argv, $argc);
-               while (my ($old_io, $mode, $tmpfh) = splice(@rdr, 0, 3)) {
-                       open $old_io, $mode, $tmpfh or die "open $mode: $!";
-               }
-               %ENV = (%ENV, %env);
-               exec(@argv);
-               die "exec: @argv: $!";
+               POSIX::setsid() > 0 or die "setsid: $!";
+               return; # continue $recv_cmd in background
        }
-}
+       my %env = map { split(/=/, $_, 2) } splice(@argv, $argc);
+       while (my ($old_io, $tmpfh) = splice(@rdr, 0, 2)) {
+               open $old_io, '+<&', $tmpfh or die "open +<&=: $!";
+       }
+       @ENV{keys %env} = values %env;
+       exec(@argv);
+       warn "exec: @argv: $!\n";
+       POSIX::_exit(1);
+};
 
 if ($send_cmd && eval {
        my $path = do {
@@ -74,36 +71,43 @@ connect($path): $! (after attempted daemon start)
 Falling back to (slow) one-shot mode
 
        }
-       1;
-}) { # (Socket::MsgHdr|Inline::C), $sock, $pwd are all available:
+       # (Socket::MsgHdr|Inline::C), $sock are all available:
        open my $dh, '<', '.' or die "open(.) $!";
        my $buf = join("\0", scalar(@ARGV), @ARGV);
        while (my ($k, $v) = each %ENV) { $buf .= "\0$k=$v" }
        $buf .= "\0\0";
-       $send_cmd->($sock, [ 0, 1, 2, fileno($dh) ], $buf, MSG_EOR);
+       my $n = $send_cmd->($sock, [0, 1, 2, fileno($dh)], $buf, MSG_EOR);
+       if (!$n) {
+               die "sendmsg: $! (check RLIMIT_NOFILE)\n" if $!{ETOOMANYREFS};
+               die "sendmsg: $!\n";
+       }
+       1;
+}) { # connected and request sent to lei-daemon, wait for responses or EOF
        my $x_it_code = 0;
        while (1) {
-               my (@fds) = $recv_cmd->($sock, $buf, 4096 * 33);
+               my (@fds) = $recv_cmd->($sock, my $buf, 4096 * 33);
                if (scalar(@fds) == 1 && !defined($fds[0])) {
-                       last if $! == ECONNRESET;
-                       next if $! == EINTR;
+                       next if $!{EINTR};
+                       last if $!{ECONNRESET};
                        die "recvmsg: $!";
                }
                last if $buf eq '';
-               if ($buf =~ /\Ax_it ([0-9]+)\z/) {
+               if ($buf =~ /\Aexec (.+)\z/) {
+                       $exec_cmd->(\@fds, split(/\0/, $1));
+               } elsif ($buf eq '-WINCH') {
+                       kill($buf, @orig_pid); # for MUA
+               } elsif ($buf =~ /\Ax_it ([0-9]+)\z/) {
                        $x_it_code = $1 + 0;
                        last;
-               } elsif ($buf =~ /\Aexec (.+)\z/) {
-                       exec_cmd(\@fds, split(/\0/, $1));
+               } elsif ($buf =~ /\Achild_error ([0-9]+)\z/) {
+                       $x_it_code = $1 + 0;
                } else {
-                       sigchld();
                        die $buf;
                }
        }
-       sigchld();
        if (my $sig = ($x_it_code & 127)) {
                kill $sig, $$;
-               sleep;
+               sleep(1) while 1;
        }
        exit($x_it_code >> 8);
 } else { # for systems lacking Socket::MsgHdr or Inline::C