lei: avoid ETOOMANYREFS, cleanup imports

As with PublicInbox::IPC, we'll attempt to bump RLIMIT_NOFILE
and transparently workaround ETOOMANYREFS.  If that fails,
we'll give the user a hint to bump RLIMIT_NOFILE since
ETOOMANYREFS is an uncommon error which users may be unfamiliar
with.

Found while stress testing for segfaults.

diff --git a/script/lei b/script/lei
index f92dd302525fca9eb41b93ee580264c588e659c6..58f0dbe92f90b36d243cfd46e1dc21a9aa31e96f 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 $send_cmd = PublicInbox::CmdIPC4->can('send_cmd4') // do {
        require PublicInbox::Spawn; # takes ~50ms even if built *sigh*
@@ -73,20 +72,32 @@ connect($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) or
-               die "sendmsg: $!";
+       my $n = $send_cmd->($sock, [0, 1, 2, fileno($dh)], $buf, MSG_EOR);
+       if (!$n && $!{ETOOMANYREFS} && eval { require BSD::Resource }) {
+               my $NOFILE = BSD::Resource::RLIMIT_NOFILE();
+               my ($s, $h) = BSD::Resource::getrlimit($NOFILE);
+               if ($s < $h && BSD::Resource::setrlimit($NOFILE, $h, $h)) {
+                       $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 '';