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From: Eric Wong <e@80x24.org>
To: meta@public-inbox.org
Subject: [PATCH 1/2] send and receive all 3 FDs at once
Date: Sun,  3 Jan 2021 11:24:50 +0000	[thread overview]
Message-ID: <20210103112451.75313-2-e@80x24.org> (raw)
In-Reply-To: <20210103112451.75313-1-e@80x24.org>

We'll always be transferring stdin, stdout, and stderr together
for lei.  Perhaps I lack imagination or foresight, but I can't
think of a reason to send more or less FDs.
---
 lib/PublicInbox/LEI.pm   | 27 ++++++++++----------
 lib/PublicInbox/Spawn.pm | 53 ++++++++++++++++++++++++++--------------
 script/lei               |  6 ++---
 t/lei.t                  |  2 +-
 t/spawn.t                | 33 ++++++++++++++++---------
 5 files changed, 74 insertions(+), 47 deletions(-)

diff --git a/lib/PublicInbox/LEI.pm b/lib/PublicInbox/LEI.pm
index 6f98c934..3ad5e01a 100644
--- a/lib/PublicInbox/LEI.pm
+++ b/lib/PublicInbox/LEI.pm
@@ -25,7 +25,7 @@ use Text::Wrap qw(wrap);
 use File::Path qw(mkpath);
 use File::Spec;
 our $quit = \&CORE::exit;
-my $recv_fd;
+my $recv_3fds;
 my $GLP = Getopt::Long::Parser->new;
 $GLP->configure(qw(gnu_getopt no_ignore_case auto_abbrev));
 my $GLP_PASS = Getopt::Long::Parser->new;
@@ -614,25 +614,26 @@ sub accept_dispatch { # Listener {post_accept} callback
 	my $self = bless { sock => $sock }, __PACKAGE__;
 	vec(my $rin = '', fileno($sock), 1) = 1;
 	# `say $sock' triggers "die" in lei(1)
-	for my $i (0..2) {
-		if (select(my $rout = $rin, undef, undef, 1)) {
-			my $fd = $recv_fd->(fileno($sock));
-			if ($fd >= 0) {
-				my $rdr = ($fd == 0 ? '<&=' : '>&=');
+	if (select(my $rout = $rin, undef, undef, 1)) {
+		my @fds = $recv_3fds->(fileno($sock));
+		if (scalar(@fds) == 3) {
+			my $i = 0;
+			for my $rdr (qw(<&= >&= >&=)) {
+				my $fd = shift(@fds);
 				if (open(my $fh, $rdr, $fd)) {
-					$self->{$i} = $fh;
-				} else {
+					$self->{$i++} = $fh;
+				}  else {
 					say $sock "open($rdr$fd) (FD=$i): $!";
 					return;
 				}
-			} else {
-				say $sock "recv FD=$i: $!";
-				return;
 			}
 		} else {
-			say $sock "timed out waiting to recv FD=$i";
+			say $sock "recv_3fds failed: $!";
 			return;
 		}
+	} else {
+		say $sock "timed out waiting to recv FDs";
+		return;
 	}
 	# $ARGV_STR = join("]\0[", @ARGV);
 	# $ENV_STR = join('', map { "$_=$ENV{$_}\0" } keys %ENV);
@@ -672,7 +673,7 @@ sub lazy_start {
 	my $dev_ino_expect = pack('dd', $st[0], $st[1]); # dev+ino
 	pipe(my ($eof_r, $eof_w)) or die "pipe: $!";
 	my $oldset = PublicInbox::Sigfd::block_signals();
-	$recv_fd = PublicInbox::Spawn->can('recv_fd') or die
+	$recv_3fds = PublicInbox::Spawn->can('recv_3fds') or die
 		"Inline::C not installed/configured or IO::FDPass missing\n";
 	require PublicInbox::Listener;
 	require PublicInbox::EOFpipe;
diff --git a/lib/PublicInbox/Spawn.pm b/lib/PublicInbox/Spawn.pm
index 4ca94b9f..61e95433 100644
--- a/lib/PublicInbox/Spawn.pm
+++ b/lib/PublicInbox/Spawn.pm
@@ -207,56 +207,67 @@ my $fdpass = <<'FDPASS';
 #include <sys/socket.h>
 
 #if defined(CMSG_SPACE) && defined(CMSG_LEN)
+struct my_3fds { int fds[3]; };
 union my_cmsg {
 	struct cmsghdr hdr;
-	char pad[sizeof(struct cmsghdr)+8+sizeof(int)+8];
+	char pad[sizeof(struct cmsghdr)+ 8 + sizeof(struct my_3fds) + 8];
 };
 
-int send_fd(int sockfd, int fd)
+int send_3fds(int sockfd, int infd, int outfd, int errfd)
 {
 	struct msghdr msg = { 0 };
 	struct iovec iov;
 	union my_cmsg cmsg = { 0 };
+	int *fdp;
+	size_t i;
 
-	iov.iov_base = &msg.msg_namelen;
+	iov.iov_base = &msg.msg_namelen; /* whatever */
 	iov.iov_len = 1;
 	msg.msg_iov = &iov;
 	msg.msg_iovlen = 1;
 	msg.msg_control = &cmsg.hdr;
-	msg.msg_controllen = CMSG_SPACE(sizeof(int));
+	msg.msg_controllen = CMSG_SPACE(sizeof(struct my_3fds));
 
 	cmsg.hdr.cmsg_level = SOL_SOCKET;
 	cmsg.hdr.cmsg_type = SCM_RIGHTS;
-	cmsg.hdr.cmsg_len = CMSG_LEN(sizeof(int));
-	*(int *)CMSG_DATA(&cmsg.hdr) = fd;
-
+	cmsg.hdr.cmsg_len = CMSG_LEN(sizeof(struct my_3fds));
+	fdp = (int *)CMSG_DATA(&cmsg.hdr);
+	*fdp++ = infd;
+	*fdp++ = outfd;
+	*fdp++ = errfd;
 	return sendmsg(sockfd, &msg, 0) >= 0;
 }
 
-int recv_fd(int sockfd)
+void recv_3fds(int sockfd)
 {
 	union my_cmsg cmsg = { 0 };
 	struct msghdr msg = { 0 };
 	struct iovec iov;
-	int fd = -1;
+	size_t i;
+	Inline_Stack_Vars;
 
-	iov.iov_base = &msg.msg_namelen;
+	iov.iov_base = &msg.msg_namelen; /* whatever */
 	iov.iov_len = 1;
 	msg.msg_iov = &iov;
 	msg.msg_iovlen = 1;
 	msg.msg_control = &cmsg.hdr;
-	msg.msg_controllen = CMSG_SPACE(sizeof(int));
+	msg.msg_controllen = CMSG_SPACE(sizeof(struct my_3fds));
 
 	if (recvmsg(sockfd, &msg, 0) <= 0)
-		return -1;
+		return;
 
 	errno = EDOM;
+	Inline_Stack_Reset;
 	if (cmsg.hdr.cmsg_level == SOL_SOCKET &&
 			cmsg.hdr.cmsg_type == SCM_RIGHTS &&
-			cmsg.hdr.cmsg_len == CMSG_LEN(sizeof(int)))
-		fd = *(int *)CMSG_DATA(&cmsg.hdr);
+			cmsg.hdr.cmsg_len == CMSG_LEN(sizeof(struct my_3fds))) {
+		int *fdp = (int *)CMSG_DATA(&cmsg.hdr);
+		size_t i;
 
-	return fd;
+		for (i = 0; i < 3; i++)
+			Inline_Stack_Push(sv_2mortal(newSViv(*fdp++)));
+	}
+	Inline_Stack_Done;
 }
 #endif /* defined(CMSG_SPACE) && defined(CMSG_LEN) */
 FDPASS
@@ -275,7 +286,8 @@ if (defined $vfork_spawn) {
 		my $f = "$inline_dir/.public-inbox.lock";
 		open my $fh, '>', $f or die "failed to open $f: $!\n";
 		flock($fh, LOCK_EX) or die "LOCK_EX failed on $f: $!\n";
-		eval 'use Inline C => $vfork_spawn . $fdpass . $set_nodatacow';
+		eval 'use Inline C => $vfork_spawn.$fdpass.$set_nodatacow';
+			# . ', BUILD_NOISY => 1';
 		my $err = $@;
 		my $ndc_err;
 		if ($err && $set_nodatacow) { # missing Linux kernel headers
@@ -303,12 +315,15 @@ unless ($set_nodatacow) {
 	*nodatacow_fd = \&PublicInbox::NDC_PP::nodatacow_fd;
 	*nodatacow_dir = \&PublicInbox::NDC_PP::nodatacow_dir;
 }
-unless (__PACKAGE__->can('recv_fd')) {
+unless (__PACKAGE__->can('recv_3fds')) {
 	eval { # try the XS IO::FDPass package
 		require IO::FDPass;
 		no warnings 'once';
-		*recv_fd = \&IO::FDPass::recv;
-		*send_fd = \&IO::FDPass::send;
+		*recv_3fds = sub { map { IO::FDPass::recv($_[0]) } (0..2) };
+		*send_3fds = sub ($$$$) {
+			my $sockfd = shift;
+			IO::FDPass::send($sockfd, shift) for (0..2);
+		};
 	};
 }
 
diff --git a/script/lei b/script/lei
index 67e8b8b0..029881f8 100755
--- a/script/lei
+++ b/script/lei
@@ -4,10 +4,10 @@
 use strict;
 use v5.10.1;
 use Socket qw(AF_UNIX SOCK_STREAM pack_sockaddr_un);
-my $send_fd;
+my $send_3fds;
 if (my ($sock, $pwd) = eval {
 	require PublicInbox::Spawn;
-	$send_fd = PublicInbox::Spawn->can('send_fd') or die
+	$send_3fds = PublicInbox::Spawn->can('send_3fds') or die
 		"Inline::C not installed/configured or IO::FDPass missing\n";
 	my $path = do {
 		my $runtime_dir = ($ENV{XDG_RUNTIME_DIR} // '') . '/lei';
@@ -60,7 +60,7 @@ Falling back to (slow) one-shot mode
 	$buf .= "\0\0";
 	select $sock;
 	$| = 1; # unbuffer selected $sock
-	$send_fd->(fileno($sock), $_) for (0..2);
+	$send_3fds->(fileno($sock), 0, 1, 2);
 	print $sock $buf or die "print(sock, buf): $!";
 	while ($buf = <$sock>) {
 		$buf =~ /\Aexit=([0-9]+)\n\z/ and exit($1 + 0);
diff --git a/t/lei.t b/t/lei.t
index 662fc545..42c0eb8f 100644
--- a/t/lei.t
+++ b/t/lei.t
@@ -195,7 +195,7 @@ SKIP: { # real socket
 	require_mods(qw(Cwd), my $nr = 46);
 	require PublicInbox::Spawn;
 	skip "Inline::C not installed/configured or IO::FDPass missing", $nr
-		unless PublicInbox::Spawn->can('send_fd');
+		unless PublicInbox::Spawn->can('send_3fds');
 
 	local $ENV{XDG_RUNTIME_DIR} = "$home/xdg_run";
 	my $sock = "$ENV{XDG_RUNTIME_DIR}/lei/sock";
diff --git a/t/spawn.t b/t/spawn.t
index e5cb09d9..891a3702 100644
--- a/t/spawn.t
+++ b/t/spawn.t
@@ -8,20 +8,31 @@ use PublicInbox::Sigfd;
 use Socket qw(AF_UNIX SOCK_STREAM);
 
 SKIP: {
-	my $recv_fd = PublicInbox::Spawn->can('recv_fd');
-	my $send_fd = PublicInbox::Spawn->can('send_fd');
-	skip 'Inline::C not enabled', 3 unless $send_fd && $recv_fd;
+	my $recv_3fds = PublicInbox::Spawn->can('recv_3fds');
+	my $send_3fds = PublicInbox::Spawn->can('send_3fds');
+	skip 'Inline::C not enabled', 3 unless $send_3fds && $recv_3fds;
 	my ($s1, $s2);
 	socketpair($s1, $s2, AF_UNIX, SOCK_STREAM, 0) or BAIL_OUT $!;
 	pipe(my ($r, $w)) or BAIL_OUT $!;
-	ok($send_fd->(fileno($s1), fileno($r)), 'pipe sent');
-	my $rfd = $recv_fd->(fileno($s2));
-	like($rfd, qr/\A\d+\z/, 'got FD');
-	open(my $rfh, '<&=', $rfd) or BAIL_OUT $!;
-	my @old = stat($r);
-	my @new = stat($rfh);
-	is("$old[0]\0$old[1]", "$new[0]\0$new[1]",
-		'device/inode matches on received FD');
+	my @orig = ($r, $w, $s2);
+	my @fd = map { fileno($_) } @orig;
+	ok($send_3fds->(fileno($s1), $fd[0], $fd[1], $fd[2]),
+		'FDs sent');
+	my (@fds) = $recv_3fds->(fileno($s2));
+	is(scalar(@fds), 3, 'got 3 fds');
+	use Data::Dumper; diag Dumper(\@fds);
+	is(scalar(grep(/\A\d+\z/, @fds)), 3, 'all valid FDs');
+	my $i = 0;
+	my @cmp = map {
+		open my $new, $_, shift(@fds) or BAIL_OUT "open $! $i => $_";
+		($new, shift(@orig), $i++);
+	} (qw(<&= >&= +<&=));
+	while (my ($new, $old, $fd) = splice(@cmp, 0, 3)) {
+		my @new = stat($new);
+		my @old = stat($old);
+		is("$old[0]\0$old[1]", "$new[0]\0$new[1]",
+			"device/inode matches on received FD:$fd");
+	}
 }
 
 {

  reply	other threads:[~2021-01-03 11:24 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-03  9:48 [PATCH 0/3] lei-related test fixes Eric Wong
2021-01-03  9:48 ` [PATCH 1/3] t/lei: use $lei->() callback wrapper Eric Wong
2021-01-03  9:48 ` [PATCH 2/3] testcommon: prepare_redirects: fix error message Eric Wong
2021-01-03  9:48 ` [PATCH 3/3] spawn: support send_fd+recv_fd w/o IO::FDPass Eric Wong
2021-01-03 11:24 ` [PATCH 0/2] fix race from stdout buffering in FD pass exit Eric Wong
2021-01-03 11:24   ` Eric Wong [this message]
2021-01-03 11:24   ` [PATCH 2/2] lei: fix output race in client/daemon mode Eric Wong

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