From e3944dfcfb3c0d8964d7cd458a9f14bbf503d00f Mon Sep 17 00:00:00 2001
From: Eric Wong <e@yhbt.net>
Date: Mon, 10 Aug 2020 02:11:56 +0000
Subject: [PATCH] index+xcpdb: improve SIG{INT,TERM,HUP,PIPE} behavior

-index now invokes ->DESTROY like xcpdb does, which is necessary
to cleanup $INBOX_DIR/msgmap-XXXXXXX files.  We'll also exit
with the expected values for various signals by adding 128
as described in <https://www.tldp.org/LDP/abs/html/exitcodes.html>

-xcpdb now terminates worker processes and xapian-compact(1)
invocations when prematurely killed, too.
---
 lib/PublicInbox/Admin.pm  | 29 +++++++++++++++++++++++++----
 lib/PublicInbox/Xapcmd.pm | 28 +++++++++++++++++++---------
 2 files changed, 44 insertions(+), 13 deletions(-)

diff --git a/lib/PublicInbox/Admin.pm b/lib/PublicInbox/Admin.pm
index e42b01e0..af2b3da9 100644
--- a/lib/PublicInbox/Admin.pm
+++ b/lib/PublicInbox/Admin.pm
@@ -5,14 +5,28 @@
 # Unstable internal API
 package PublicInbox::Admin;
 use strict;
-use warnings;
-use Cwd 'abs_path';
-use base qw(Exporter);
-our @EXPORT_OK = qw(resolve_repo_dir);
+use parent qw(Exporter);
+use Cwd qw(abs_path);
+use POSIX ();
+our @EXPORT_OK = qw(resolve_repo_dir setup_signals);
 use PublicInbox::Config;
 use PublicInbox::Inbox;
 use PublicInbox::Spawn qw(popen_rd);
 
+sub setup_signals {
+	my ($cb, $arg) = @_; # optional
+
+	# we call exit() here instead of _exit() so DESTROY methods
+	# get called (e.g. File::Temp::Dir and PublicInbox::Msgmap)
+	$SIG{INT} = $SIG{HUP} = $SIG{PIPE} = $SIG{TERM} = sub {
+		my ($sig) = @_;
+		# https://www.tldp.org/LDP/abs/html/exitcodes.html
+		eval { $cb->($sig, $arg) } if $cb;
+		$sig = 'SIG'.$sig;
+		exit(128 + POSIX->$sig);
+	};
+}
+
 sub resolve_repo_dir {
 	my ($cd, $ver) = @_;
 	my $prefix = defined $cd ? $cd : './';
@@ -185,9 +199,16 @@ invalid indexlevel=$indexlevel (must be `basic', `medium', or `full')
 	die missing_mod_msg($err) ." required for indexlevel=$indexlevel\n";
 }
 
+sub index_terminate {
+	my (undef, $ibx) = @_; # $_[0] = signal name
+	$ibx->git->cleanup;
+}
+
 sub index_inbox {
 	my ($ibx, $im, $opt) = @_;
 	my $jobs = delete $opt->{jobs} if $opt;
+	local %SIG = %SIG;
+	setup_signals(\&index_terminate, $ibx);
 	if (ref($ibx) && $ibx->version == 2) {
 		eval { require PublicInbox::V2Writable };
 		die "v2 requirements not met: $@\n" if $@;
diff --git a/lib/PublicInbox/Xapcmd.pm b/lib/PublicInbox/Xapcmd.pm
index 714f6859..348621ce 100644
--- a/lib/PublicInbox/Xapcmd.pm
+++ b/lib/PublicInbox/Xapcmd.pm
@@ -2,8 +2,8 @@
 # License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
 package PublicInbox::Xapcmd;
 use strict;
-use warnings;
 use PublicInbox::Spawn qw(which popen_rd nodatacow_dir);
+use PublicInbox::Admin qw(setup_signals);
 use PublicInbox::Over;
 use PublicInbox::SearchIdx;
 use File::Temp 0.19 (); # ->newdir
@@ -126,6 +126,11 @@ sub same_fs_or_die ($$) {
 	die "$x and $y reside on different filesystems\n";
 }
 
+sub kill_pids {
+	my ($sig, $pids) = @_;
+	kill($sig, keys %$pids); # pids may be empty
+}
+
 sub process_queue {
 	my ($queue, $cb, $opt) = @_;
 	my $max = $opt->{jobs} // scalar(@$queue);
@@ -138,6 +143,8 @@ sub process_queue {
 
 	# run in parallel:
 	my %pids;
+	local %SIG = %SIG;
+	setup_signals(\&kill_pids, \%pids);
 	while (@$queue) {
 		while (scalar(keys(%pids)) < $max && scalar(@$queue)) {
 			my $args = shift @$queue;
@@ -156,12 +163,6 @@ sub process_queue {
 	}
 }
 
-sub setup_signals () {
-	# http://www.tldp.org/LDP/abs/html/exitcodes.html
-	$SIG{INT} = sub { exit(130) };
-	$SIG{HUP} = $SIG{PIPE} = $SIG{TERM} = sub { exit(1) };
-}
-
 sub prepare_run {
 	my ($ibx, $opt) = @_;
 	my $tmp = {}; # old shard dir => File::Temp->newdir object or undef
@@ -294,6 +295,11 @@ sub progress_pfx ($) {
 	($p[-1] =~ /\A([0-9]+)/) ? "$p[-2]/$1" : $p[-1];
 }
 
+sub kill_compact { # setup_signals callback
+	my ($sig, $pidref) = @_;
+	kill($sig, $$pidref) if defined($$pidref);
+}
+
 # xapian-compact wrapper
 sub compact ($$) {
 	my ($args, $opt) = @_;
@@ -319,14 +325,18 @@ sub compact ($$) {
 	}
 	$pr->("$pfx `".join(' ', @$cmd)."'\n") if $pr;
 	push @$cmd, $src, $dst;
-	my $rd = popen_rd($cmd, undef, $rdr);
+	my ($rd, $pid);
+	local %SIG = %SIG;
+	setup_signals(\&kill_compact, \$pid);
+	($rd, $pid) = popen_rd($cmd, undef, $rdr);
 	while (<$rd>) {
 		if ($pr) {
 			s/\r/\r$pfx /g;
 			$pr->("$pfx $_");
 		}
 	}
-	close $rd or die join(' ', @$cmd)." failed: $?n";
+	waitpid($pid, 0);
+	die "@$cmd failed: \$?=$?\n" if $?;
 }
 
 sub cpdb_loop ($$$;$$) {
-- 
2.44.0