[PATCH 1/7] tests: map CLOFORK->FD_CLOEXEC temporarily for `tail -f'

[Eric Wong]

This fixes `TAIL="tail -F" prove -bvw t/lei-refresh-mail-sync.t'
since that test relies on lacking FD_CLOEXEC to detect dead
lei-daemons, but we still want FD_CLOEXEC when when relying
on tail(1) to check -imapd output.
---
 lib/PublicInbox/TestCommon.pm | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/lib/PublicInbox/TestCommon.pm b/lib/PublicInbox/TestCommon.pm
index ec300b3f..b7f1eb57 100644
--- a/lib/PublicInbox/TestCommon.pm
+++ b/lib/PublicInbox/TestCommon.pm
@@ -6,7 +6,7 @@ package PublicInbox::TestCommon;
 use strict;
 use parent qw(Exporter);
 use v5.10.1;
-use Fcntl qw(F_SETFD :seek);
+use Fcntl qw(F_SETFD F_GETFD FD_CLOEXEC :seek);
 use POSIX qw(dup2);
 use IO::Socket::INET;
 use File::Spec;
@@ -326,7 +326,7 @@ sub run_script ($;$$) {
                        die "unable to deal with $ref $redir";
                }
        }
-       my $tail = @tail_paths ? tail_f(@tail_paths) : undef;
+       my $tail = @tail_paths ? tail_f(@tail_paths, $opt) : undef;
        if ($key =~ /-(index|cindex|extindex|convert|xcpdb)\z/) {
                unshift @argv, '--no-fsync';
        }
@@ -442,11 +442,23 @@ sub xqx {
 }
 
 sub tail_f (@) {
+       my @f = grep(defined, @_);
        $tail_cmd or return; # "tail -F" or "tail -f"
-       for (@_) { open(my $fh, '>>', $_) or die $! };
-       my $cmd = [ split(/ /, $tail_cmd), @_ ];
+       my $opt = (ref($f[-1]) eq 'HASH') ? pop(@f) : {};
+       my $clofork = $opt->{-CLOFORK} // [];
+       use autodie qw(fcntl open);
+       my @cfmap = map {
+               my $fl = fcntl($_, F_GETFD, 0);
+               fcntl($_, F_SETFD, $fl | FD_CLOEXEC) unless $fl & FD_CLOEXEC;
+               ($_, $fl);
+       } @$clofork;
+       for (@f) { open(my $fh, '>>', $_) };
+       my $cmd = [ split(/ /, $tail_cmd), @f ];
        require PublicInbox::Spawn;
        my $pid = PublicInbox::Spawn::spawn($cmd, undef, { 1 => 2 });
+       while (my ($io, $fl) = splice(@cfmap, 0, 2)) {
+               fcntl($io, F_SETFD, $fl);
+       }
        wait_for_tail($pid, scalar @_);
        require PublicInbox::AutoReap;
        PublicInbox::AutoReap->new($pid, \&wait_for_tail);
@@ -476,7 +488,7 @@ sub start_script {
                                }
                        }
                }
-               $tail = tail_f(@paths);
+               $tail = tail_f(@paths, $opt);
        }
        my $oset = PublicInbox::DS::block_signals();
        require PublicInbox::OnDestroy;