[PATCH 2.5/9] lei: fix implicit stdin support for pipes

[Eric Wong <e@80x24.org>]

Eric Wong <e@80x24.org> wrote:
> +++ b/t/lei-store-fail.t

> +	my $cmd = [ qw(lei import -q -F mboxrd) ];
> +	my $tp = start_script($cmd, undef, $opt);

Of course the lack of `-' or  `--stdin' only worked on Linux and
NetBSD, but not other BSDs.

-------8<------
Subject: [PATCH] lei: fix implicit stdin support for pipes

st_mode permission bits can't be used to determine if a file or
pipe we have on stdin readable or not.  Writable regular files
can be opened O_RDONLY, and permissions bits for pipes are
inconsistent across platforms.

On FreeBSD, OpenBSD, and Dragonfly, only the S_IFIFO bit is set
in st_mode with none of the permission bits are set.  Linux and
NetBSD have both the read and write permission bits set for both
ends of a the pipe, so they're just as inaccurate but allowed
the feature to work before this change.

For now, we'll just assume our users know that stdin is intended
for input and consider any pipe or regular file to be readable.

If we were to be pedantic, we'd check O_RDONLY or O_RDWR
description flags via the F_GETFL fcntl(2) op to determine if a
pipe or socket is readable.  However, I don't think it's worth
the code to do so.
---
 lib/PublicInbox/LEI.pm | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index f00b2465..1ba2c2a1 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -747,7 +747,7 @@ sub optparse ($$$) {
 					# w/o args means stdin
 					if ($sw eq 'stdin' && !@$argv &&
 							(-p $self->{0} ||
-							 -f _) && -r _) {
+							 -f _)) {
 						$OPT->{stdin} //= 1;
 					}
 					$ok = defined($OPT->{$sw}) and last;