[PATCH 14/30] ds: introduce and use do_fork helper

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

This ensures we handle RNG reseeding and resetting the event
loop properly in child processes after forking.
---
 lib/PublicInbox/DS.pm         | 12 ++++++++++++
 lib/PublicInbox/Daemon.pm     | 16 +++++-----------
 lib/PublicInbox/IPC.pm        | 12 ++----------
 lib/PublicInbox/TestCommon.pm |  3 +--
 lib/PublicInbox/Watch.pm      | 11 ++---------
 lib/PublicInbox/Xapcmd.pm     |  5 ++---
 6 files changed, 24 insertions(+), 35 deletions(-)

diff --git a/lib/PublicInbox/DS.pm b/lib/PublicInbox/DS.pm
index eefbdcc3..9960937d 100644
--- a/lib/PublicInbox/DS.pm
+++ b/lib/PublicInbox/DS.pm
@@ -34,6 +34,7 @@ use PublicInbox::Tmpfile;
 use PublicInbox::Select;
 use Errno qw(EAGAIN EINVAL ECHILD);
 use Carp qw(carp croak);
+use autodie qw(fork);
 our @EXPORT_OK = qw(now msg_more awaitpid add_timer add_uniq_timer);
 
 my $nextq; # queue for next_tick
@@ -737,6 +738,17 @@ sub awaitpid {
 	}
 }
 
+sub do_fork () {
+	my $seed = rand(0xffffffff);
+	my $pid = fork;
+	if ($pid == 0) {
+		srand($seed);
+		eval { Net::SSLeay::randomize() };
+		Reset();
+	}
+	$pid;
+}
+
 package PublicInbox::DummyPoller; # only used during Reset
 use v5.12;
 
diff --git a/lib/PublicInbox/Daemon.pm b/lib/PublicInbox/Daemon.pm
index 520cef72..f33f6f17 100644
--- a/lib/PublicInbox/Daemon.pm
+++ b/lib/PublicInbox/Daemon.pm
@@ -541,17 +541,11 @@ sub reap_worker { # awaitpid CB
 
 sub start_worker ($) {
 	my ($nr) = @_;
-	my $seed = rand(0xffffffff);
 	return unless @listeners;
-	my $pid = fork;
-	if (!defined($pid)) {
-		warn "fork: $!";
-	} elsif ($pid == 0) {
+	my $pid = PublicInbox::DS::do_fork;
+	if ($pid == 0) {
 		undef %WORKERS;
-		PublicInbox::DS::Reset();
 		local $PublicInbox::DS::Poller; # allow epoll/kqueue
-		srand($seed);
-		eval { Net::SSLeay::randomize() };
 		$set_user->() if $set_user;
 		PublicInbox::EOFpipe->new($parent_pipe, \&worker_quit);
 		worker_loop();
@@ -563,9 +557,9 @@ sub start_worker ($) {
 }
 
 sub start_workers {
-	for my $nr (grep { !defined($WORKERS{$_}) } (0..($nworker - 1))) {
-		start_worker($nr);
-	}
+	my @idx = grep { !defined($WORKERS{$_}) } (0..($nworker - 1)) or return;
+	eval { start_worker($_) for @idx };
+	warn "E: $@\n" if $@;
 }
 
 sub trim_workers {
diff --git a/lib/PublicInbox/IPC.pm b/lib/PublicInbox/IPC.pm
index 5964645e..3292d960 100644
--- a/lib/PublicInbox/IPC.pm
+++ b/lib/PublicInbox/IPC.pm
@@ -102,12 +102,8 @@ sub ipc_worker_spawn {
 	pipe(my $r_res, my $w_res);
 	my $sigset = $oldset // PublicInbox::DS::block_signals();
 	$self->ipc_atfork_prepare;
-	my $seed = rand(0xffffffff);
-	my $pid = fork;
+	my $pid = PublicInbox::DS::do_fork;
 	if ($pid == 0) {
-		srand($seed);
-		eval { Net::SSLeay::randomize() };
-		eval { PublicInbox::DS->Reset };
 		delete @$self{qw(-wq_s1 -wq_s2 -wq_workers -wq_ppid)};
 		$w_req = $r_res = undef;
 		$w_res->autoflush(1);
@@ -341,13 +337,9 @@ sub _wq_worker_start {
 	my ($self, $oldset, $fields, $one, @cb_args) = @_;
 	my ($bcast1, $bcast2);
 	$one or socketpair($bcast1, $bcast2, AF_UNIX, SOCK_SEQPACKET, 0);
-	my $seed = rand(0xffffffff);
-	my $pid = fork;
+	my $pid = PublicInbox::DS::do_fork;
 	if ($pid == 0) {
-		srand($seed);
-		eval { Net::SSLeay::randomize() };
 		undef $bcast1;
-		eval { PublicInbox::DS->Reset };
 		delete @$self{qw(-wq_s1 -wq_ppid)};
 		$self->{-wq_worker_nr} =
 				keys %{delete($self->{-wq_workers}) // {}};
diff --git a/lib/PublicInbox/TestCommon.pm b/lib/PublicInbox/TestCommon.pm
index 323152b4..77da822b 100644
--- a/lib/PublicInbox/TestCommon.pm
+++ b/lib/PublicInbox/TestCommon.pm
@@ -549,9 +549,8 @@ sub start_script {
 	require PublicInbox::OnDestroy;
 	my $tmp_mask = PublicInbox::OnDestroy->new(
 					\&PublicInbox::DS::sig_setmask, $oset);
-	my $pid = fork // die "fork: $!";
+	my $pid = PublicInbox::DS::do_fork();
 	if ($pid == 0) {
-		eval { PublicInbox::DS->Reset };
 		for (@{delete($opt->{-CLOFORK}) // []}) {
 			close($_) or die "close $!";
 		}
diff --git a/lib/PublicInbox/Watch.pm b/lib/PublicInbox/Watch.pm
index 3426d4a7..41b77dc1 100644
--- a/lib/PublicInbox/Watch.pm
+++ b/lib/PublicInbox/Watch.pm
@@ -385,7 +385,6 @@ sub watch_atfork_child ($) {
 	my ($self) = @_;
 	delete $self->{pids};
 	delete $self->{opendirs};
-	PublicInbox::DS->Reset;
 	my $sig = delete $self->{sig};
 	$sig->{CHLD} = $sig->{HUP} = $sig->{USR1} = 'DEFAULT';
 	# TERM/QUIT/INT call ->quit, which works in both parent+child
@@ -413,11 +412,8 @@ sub imap_idle_reap { # awaitpid callback
 sub imap_idle_fork {
 	my ($self, $uri, $intvl) = @_;
 	return if $self->{quit};
-	my $seed = rand(0xffffffff);
-	my $pid = fork // die "fork: $!";
+	my $pid = PublicInbox::DS::do_fork;
 	if ($pid == 0) {
-		srand($seed);
-		eval { Net::SSLeay::randomize() };
 		watch_atfork_child($self);
 		watch_imap_idle_1($self, $uri, $intvl);
 		_exit(0);
@@ -477,11 +473,8 @@ sub poll_fetch_fork { # DS::add_timer callback
 	my @imap = grep { # push() always returns > 0
 		$_->scheme =~ m!\Aimaps?!i ? 1 : (push(@nntp, $_) < 0)
 	} @$uris;
-	my $seed = rand(0xffffffff);
-	my $pid = fork // die "fork: $!";
+	my $pid = PublicInbox::DS::do_fork;
 	if ($pid == 0) {
-		srand($seed);
-		eval { Net::SSLeay::randomize() };
 		watch_atfork_child($self);
 		watch_imap_fetch_all($self, \@imap) if @imap;
 		watch_nntp_fetch_all($self, \@nntp) if @nntp;
diff --git a/lib/PublicInbox/Xapcmd.pm b/lib/PublicInbox/Xapcmd.pm
index 4e055acf..c2b66e69 100644
--- a/lib/PublicInbox/Xapcmd.pm
+++ b/lib/PublicInbox/Xapcmd.pm
@@ -11,6 +11,7 @@ use PublicInbox::SearchIdx;
 use File::Temp 0.19 (); # ->newdir
 use File::Path qw(remove_tree);
 use POSIX qw(WNOHANG _exit);
+use PublicInbox::DS;
 
 # support testing with dev versions of Xapian which installs
 # commands with a version number suffix (e.g. "xapian-compact-1.5")
@@ -102,10 +103,8 @@ sub commit_changes ($$$$) {
 
 sub cb_spawn {
 	my ($cb, $args, $opt) = @_; # $cb = cpdb() or compact()
-	my $seed = rand(0xffffffff);
-	my $pid = fork // die "fork: $!";
+	my $pid = PublicInbox::DS::do_fork;
 	return $pid if $pid > 0;
-	srand($seed);
 	$SIG{__DIE__} = sub { warn @_; _exit(1) }; # don't jump up stack
 	$cb->($args, $opt);
 	_exit(0);