[PATCH] spawn: support some rlimit uses via Inline::C

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

BSD::Resource isn't packaged for Alpine (as of 3.19), but we
also have optional Inline::C support and already rely on calling
setrlimit(2) directly from the Inline::C version of pi_fork_exec.
---
 lib/PublicInbox/ExtSearchIdx.pm |  1 +
 lib/PublicInbox/Limiter.pm      | 15 +++++++++------
 lib/PublicInbox/Spawn.pm        | 31 ++++++++++++++++++++++++-------
 t/spawn.t                       | 21 +++++++++++++--------
 4 files changed, 47 insertions(+), 21 deletions(-)

diff --git a/lib/PublicInbox/ExtSearchIdx.pm b/lib/PublicInbox/ExtSearchIdx.pm
index 53078124..ebbffffc 100644
--- a/lib/PublicInbox/ExtSearchIdx.pm
+++ b/lib/PublicInbox/ExtSearchIdx.pm
@@ -22,6 +22,7 @@ use Scalar::Util qw(blessed);
 use Sys::Hostname qw(hostname);
 use File::Glob qw(bsd_glob GLOB_NOSORT);
 use PublicInbox::MultiGit;
+use PublicInbox::Spawn ();
 use PublicInbox::Search;
 use PublicInbox::SearchIdx qw(prepare_stack is_ancestor is_bad_blob);
 use PublicInbox::OverIdx;
diff --git a/lib/PublicInbox/Limiter.pm b/lib/PublicInbox/Limiter.pm
index 48a2b6a3..a8d08fc3 100644
--- a/lib/PublicInbox/Limiter.pm
+++ b/lib/PublicInbox/Limiter.pm
@@ -31,14 +31,17 @@ sub setup_rlimit {
 		} elsif (scalar(@rlimit) != 2) {
 			warn "could not parse $k: $v\n";
 		}
-		eval { require BSD::Resource };
-		if ($@) {
-			warn "BSD::Resource missing for $rlim";
-			next;
-		}
+		my $inf = $v =~ /\binfinity\b/i ?
+			$PublicInbox::Spawn::RLIMITS{RLIM_INFINITY} // eval {
+				require BSD::Resource;
+				BSD::Resource::RLIM_INFINITY();
+			} // do {
+				warn "BSD::Resource missing for $rlim";
+				next;
+			} : undef;
 		for my $i (0..$#rlimit) {
 			next if $rlimit[$i] ne 'INFINITY';
-			$rlimit[$i] = BSD::Resource::RLIM_INFINITY();
+			$rlimit[$i] = $inf;
 		}
 		$self->{$rlim} = \@rlimit;
 	}
diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index e6b12994..e36659ce 100644
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -21,10 +21,11 @@ use IO::Handle ();
 use Carp qw(croak);
 use PublicInbox::IO;
 our @EXPORT_OK = qw(which spawn popen_rd popen_wr run_die run_wait run_qx);
-our @RLIMITS = qw(RLIMIT_CPU RLIMIT_CORE RLIMIT_DATA);
+our (@RLIMITS, %RLIMITS);
 use autodie qw(close open pipe seek sysseek truncate);
 
 BEGIN {
+	@RLIMITS = qw(RLIMIT_CPU RLIMIT_CORE RLIMIT_DATA);
 	my $all_libc = <<'ALL_LIBC'; # all *nix systems we support
 #include <sys/resource.h>
 #include <sys/socket.h>
@@ -283,14 +284,28 @@ void recv_cmd4(PerlIO *s, SV *buf, STRLEN n)
 	Inline_Stack_Done;
 }
 #endif /* defined(CMSG_SPACE) && defined(CMSG_LEN) */
-ALL_LIBC
 
+void rlimit_map()
+{
+	Inline_Stack_Vars;
+	Inline_Stack_Reset;
+ALL_LIBC
 	my $inline_dir = $ENV{PERL_INLINE_DIRECTORY} // (
 			$ENV{XDG_CACHE_HOME} //
 			( ($ENV{HOME} // '/nonexistent').'/.cache' )
 		).'/public-inbox/inline-c';
 	undef $all_libc unless -d $inline_dir;
 	if (defined $all_libc) {
+		for (@RLIMITS, 'RLIM_INFINITY') {
+			$all_libc .= <<EOM;
+	Inline_Stack_Push(sv_2mortal(newSVpvs("$_")));
+	Inline_Stack_Push(sv_2mortal(newSViv($_)));
+EOM
+		}
+		$all_libc .= <<EOM;
+	Inline_Stack_Done;
+} // rlimit_map
+EOM
 		local $ENV{PERL_INLINE_DIRECTORY} = $inline_dir;
 		# CentOS 7.x ships Inline 0.53, 0.64+ has built-in locking
 		my $lk = PublicInbox::Lock->new($inline_dir.
@@ -316,6 +331,7 @@ ALL_LIBC
 	}
 	if (defined $all_libc) { # set for Gcf2
 		$ENV{PERL_INLINE_DIRECTORY} = $inline_dir;
+		%RLIMITS = rlimit_map();
 	} else {
 		require PublicInbox::SpawnPP;
 		*pi_fork_exec = \&PublicInbox::SpawnPP::pi_fork_exec
@@ -361,11 +377,12 @@ sub spawn ($;$$) {
 	my $rlim = [];
 	foreach my $l (@RLIMITS) {
 		my $v = $opt->{$l} // next;
-		my $r = eval "require BSD::Resource; BSD::Resource::$l();";
-		unless (defined $r) {
-			warn "$l undefined by BSD::Resource: $@\n";
-			next;
-		}
+		my $r = $RLIMITS{$l} //
+			eval "require BSD::Resource; BSD::Resource::$l();" //
+			do {
+				warn "$l undefined by BSD::Resource: $@\n";
+				next;
+			};
 		push @$rlim, $r, @$v;
 	}
 	my $cd = $opt->{'-C'} // ''; # undef => NULL mapping doesn't work?
diff --git a/t/spawn.t b/t/spawn.t
index 48f541b8..5b17ed38 100644
--- a/t/spawn.t
+++ b/t/spawn.t
@@ -6,7 +6,7 @@ use Test::More;
 use PublicInbox::Spawn qw(which spawn popen_rd run_qx);
 require PublicInbox::Sigfd;
 require PublicInbox::DS;
-
+my $rlimit_map = PublicInbox::Spawn->can('rlimit_map');
 {
 	my $true = which('true');
 	ok($true, "'true' command found with which()");
@@ -192,14 +192,19 @@ EOF
 }
 
 SKIP: {
-	eval {
-		require BSD::Resource;
-		defined(BSD::Resource::RLIMIT_CPU())
-	} or skip 'BSD::Resource::RLIMIT_CPU missing', 3;
+	if ($rlimit_map) { # Inline::C installed
+		my %rlim = $rlimit_map->();
+		ok defined($rlim{RLIMIT_CPU}), 'RLIMIT_CPU defined';
+	} else {
+		eval {
+			require BSD::Resource;
+			defined(BSD::Resource::RLIMIT_CPU())
+		} or skip 'BSD::Resource::RLIMIT_CPU missing', 3;
+	}
 	my $cmd = [ $^X, qw(-w -e), <<'EOM' ];
 use POSIX qw(:signal_h);
-use BSD::Resource qw(times);
 use Time::HiRes qw(time); # gettimeofday
+my $have_bsd_resource = eval { require BSD::Resource };
 my $set = POSIX::SigSet->new;
 $set->emptyset; # spawn() defaults to blocking all signals
 sigprocmask(SIG_SETMASK, $set) or die "SIG_SETMASK: $!";
@@ -211,10 +216,10 @@ while (1) {
 	# and `write' (via Perl warn)) on otherwise idle systems to
 	# hit RLIMIT_CPU and fire signals:
 	# https://marc.info/?i=02A4BB8D-313C-464D-845A-845EB6136B35@gmail.com
-	my @t = times;
+	my @t = $have_bsd_resource ? BSD::Resource::times() : (0, 0);
 	$tot = $t[0] + $t[1];
 	if (time > $next) {
-		warn "# T: @t (utime, ctime, cutime, cstime)\n";
+		warn "# T: @t (utime, ctime, cutime, cstime)\n" if @t;
 		$next = time + 1.1;
 	}
 }