about summary refs log tree commit homepage
path: root/lib/PublicInbox/Gcf2.pm
blob: 64945ca69cff7fa3cec96539fad0ac0a8f9bfe9d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
# Copyright (C) 2020-2021 all contributors <meta@public-inbox.org>
# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>

# backend for a git-cat-file-workalike based on libgit2,
# other libgit2 stuff may go here, too.
package PublicInbox::Gcf2;
use strict;
use v5.10.1;
use PublicInbox::Spawn qw(which popen_rd); # may set PERL_INLINE_DIRECTORY
use Fcntl qw(LOCK_EX SEEK_SET);
use IO::Handle; # autoflush
BEGIN {
	my (%CFG, $c_src);
	# PublicInbox::Spawn will set PERL_INLINE_DIRECTORY
	# to ~/.cache/public-inbox/inline-c if it exists
	my $inline_dir = $ENV{PERL_INLINE_DIRECTORY} //
		die 'PERL_INLINE_DIRECTORY not defined';
	my $f = "$inline_dir/.public-inbox.lock";
	open my $fh, '+>', $f or die "open($f): $!";

	# CentOS 7.x ships Inline 0.53, 0.64+ has built-in locking
	flock($fh, LOCK_EX) or die "LOCK_EX($f): $!\n";

	my $pc = which($ENV{PKG_CONFIG} // 'pkg-config') //
		die "pkg-config missing for libgit2";
	my ($dir) = (__FILE__ =~ m!\A(.+?)/[^/]+\z!);
	my $ef = "$inline_dir/.public-inbox.pkg-config.err";
	open my $err, '+>', $ef or die "open($ef): $!";
	for my $x (qw(libgit2)) {
		my $rdr = { 2 => $err };
		my ($l, $pid) = popen_rd([$pc, '--libs', $x], undef, $rdr);
		$l = do { local $/; <$l> };
		waitpid($pid, 0);
		next if $?;
		(my $c, $pid) = popen_rd([$pc, '--cflags', $x], undef, $rdr);
		$c = do { local $/; <$c> };
		waitpid($pid, 0);
		next if $?;

		# note: we name C source files .h to prevent
		# ExtUtils::MakeMaker from automatically trying to
		# build them.
		my $f = "$dir/gcf2_$x.h";
		open(my $src, '<', $f) or die "E: open($f): $!";
		chomp($l, $c);
		local $/;
		defined($c_src = <$src>) or die "read $f: $!";
		$CFG{LIBS} = $l;
		$CFG{CCFLAGSEX} = $c;
		last;
	}
	unless ($c_src) {
		seek($err, 0, SEEK_SET);
		$err = do { local $/; <$err> };
		die "E: libgit2 not installed: $err\n";
	}
	open my $oldout, '>&', \*STDOUT or die "dup(1): $!";
	open my $olderr, '>&', \*STDERR or die "dup(2): $!";
	open STDOUT, '>&', $fh or die "1>$f: $!";
	open STDERR, '>&', $fh or die "2>$f: $!";
	STDERR->autoflush(1);
	STDOUT->autoflush(1);

	# we use Capitalized and ALLCAPS for compatibility with old Inline::C
	eval <<'EOM';
use Inline C => Config => %CFG, BOOT => q[git_libgit2_init();];
use Inline C => $c_src, BUILD_NOISY => 1;
EOM
	$err = $@;
	open(STDERR, '>&', $olderr) or warn "restore stderr: $!";
	open(STDOUT, '>&', $oldout) or warn "restore stdout: $!";
	if ($err) {
		seek($fh, 0, SEEK_SET);
		my @msg = <$fh>;
		die "Inline::C Gcf2 build failed:\n", $err, "\n", @msg;
	}
}

sub add_alt ($$) {
	my ($gcf2, $objdir) = @_;

	# libgit2 (tested 0.27.7+dfsg.1-0.2 and 0.28.3+dfsg.1-1~bpo10+1
	# in Debian) doesn't handle relative epochs properly when nested
	# multiple levels.  Add all the absolute paths to workaround it,
	# since $EXTINDEX_DIR/ALL.git/objects/info/alternates uses absolute
	# paths to reference $V2INBOX_DIR/all.git/objects and
	# $V2INBOX_DIR/all.git/objects/info/alternates uses relative paths
	# to refer to $V2INBOX_DIR/git/$EPOCH.git/objects
	#
	# See https://bugs.debian.org/975607
	if (open(my $fh, '<', "$objdir/info/alternates")) {
		chomp(my @abs_alt = grep(m!^/!, <$fh>));
		$gcf2->add_alternate($_) for @abs_alt;
	}
	$gcf2->add_alternate($objdir);
	1;
}

# Usage: $^X -MPublicInbox::Gcf2 -e PublicInbox::Gcf2::loop
# (see lib/PublicInbox/Gcf2Client.pm)
sub loop () {
	my $gcf2 = new();
	my %seen;
	STDERR->autoflush(1);
	STDOUT->autoflush(1);

	while (<STDIN>) {
		chomp;
		my ($oid, $git_dir) = split(/ /, $_, 2);
		$seen{$git_dir} //= add_alt($gcf2, "$git_dir/objects");
		if (!$gcf2->cat_oid(1, $oid)) {
			# retry once if missing.  We only get unabbreviated OIDs
			# from SQLite or Xapian DBs, here, so malicious clients
			# can't trigger excessive retries:
			warn "I: $$ $oid missing, retrying in $git_dir\n";

			$gcf2 = new();
			%seen = ($git_dir => add_alt($gcf2,"$git_dir/objects"));

			if ($gcf2->cat_oid(1, $oid)) {
				warn "I: $$ $oid found after retry\n";
			} else {
				warn "W: $$ $oid missing after retry\n";
				print "$oid missing\n"; # mimic git-cat-file
			}
		}
	}
}

1;