-# Copyright (C) 2020 all contributors <meta@public-inbox.org>
+# 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 public-inbox-gcf2(1) (git-cat-file based on libgit2,
-# other libgit2 stuff may go here, too)
+# backend for a git-cat-file-workalike based on libgit2,
+# other libgit2 stuff may go here, too.
package PublicInbox::Gcf2;
use strict;
-use PublicInbox::Spawn qw(which popen_rd);
-use Fcntl qw(LOCK_EX);
-my (%CFG, $c_src, $lockfh);
+use v5.10.1;
+use PublicInbox::Spawn qw(which popen_rd); # may set PERL_INLINE_DIRECTORY
+use Fcntl qw(LOCK_EX SEEK_SET);
+use Time::HiRes qw(clock_gettime CLOCK_MONOTONIC);
+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 $lockfh, '>', $f or die "failed to open $f: $!\n";
- my $pc = which($ENV{PKG_CONFIG} // 'pkg-config');
+ 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 $rdr = {};
- open $rdr->{2}, '>', '/dev/null' or die "open /dev/null: $!";
+ my $ef = "$inline_dir/.public-inbox.pkg-config.err";
+ open my $err, '+>', $ef or die "open($ef): $!";
for my $x (qw(libgit2)) {
- my $l = popen_rd([$pc, '--libs', $x], undef, $rdr);
+ my $rdr = { 2 => $err };
+ my ($l, $pid) = popen_rd([$pc, '--libs', $x], undef, $rdr);
$l = do { local $/; <$l> };
+ waitpid($pid, 0);
next if $?;
- my $c = popen_rd([$pc, '--cflags', $x], undef, $rdr);
+ (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";
- if (open(my $fh, '<', $f)) {
- chomp($l, $c);
- local $/;
- $c_src = <$fh>;
- $CFG{LIBS} = $l;
- $CFG{CCFLAGSEX} = $c;
- last;
- } else {
- die "E: $f: $!\n";
- }
+ 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";
}
- die "E: libgit2 not installed\n" unless $c_src;
+ 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: $!";
+ STDERR->autoflush(1);
+ STDOUT->autoflush(1);
- # CentOS 7.x ships Inline 0.53, 0.64+ has built-in locking
- flock($lockfh, LOCK_EX) or die "LOCK_EX failed on $f: $!\n";
+ # 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 ($$) {
+ my ($gcf2, $objdir) = @_;
+
+ # libgit2 (tested 0.27.7+dfsg.1-0.2 and 0.28.3+dfsg.1-1~bpo10+1
+ # in Debian) doesn't handle relative epochs properly when nested
+ # multiple levels. Add all the absolute paths to workaround it,
+ # since $EXTINDEX_DIR/ALL.git/objects/info/alternates uses absolute
+ # paths to reference $V2INBOX_DIR/all.git/objects and
+ # $V2INBOX_DIR/all.git/objects/info/alternates uses relative paths
+ # to refer to $V2INBOX_DIR/git/$EPOCH.git/objects
+ #
+ # See https://bugs.debian.org/975607
+ if (open(my $fh, '<', "$objdir/info/alternates")) {
+ chomp(my @abs_alt = grep(m!^/!, <$fh>));
+ $gcf2->add_alternate($_) for @abs_alt;
+ }
+ $gcf2->add_alternate($objdir);
+ 1;
+}
+
+sub have_unlinked_files () {
+ # FIXME: port gcf2-like over to git.git so we won't need to
+ # deal with libgit2
+ return 1 if $^O ne 'linux';
+ open my $fh, '<', "/proc/$$/maps" or return;
+ while (<$fh>) { return 1 if /\.(?:idx|pack) \(deleted\)$/ }
+ undef;
+}
+
+# Usage: $^X -MPublicInbox::Gcf2 -e PublicInbox::Gcf2::loop [EXPIRE-TIMEOUT]
+# (see lib/PublicInbox/Gcf2Client.pm)
+sub loop (;$) {
+ my $exp = $_[0] || $ARGV[0] || 60; # seconds
+ my $gcf2 = new();
+ my (%seen, $check_at);
+ STDERR->autoflush(1);
+ STDOUT->autoflush(1);
+
+ while (<STDIN>) {
+ chomp;
+ my ($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: $$ $oid missing, retrying in $git_dir\n";
+
+ $gcf2 = new();
+ %seen = ($git_dir => add_alt($gcf2,"$git_dir/objects"));
+ $check_at = clock_gettime(CLOCK_MONOTONIC) + $exp;
+
+ if ($gcf2->cat_oid(1, $oid)) {
+ warn "I: $$ $oid found after retry\n";
+ } else {
+ warn "W: $$ $oid missing after retry\n";
+ print "$oid missing\n"; # mimic git-cat-file
+ }
+ } else { # check expiry to deal with deleted pack files
+ my $now = clock_gettime(CLOCK_MONOTONIC);
+ $check_at //= $now + $exp;
+ if ($now > $check_at) {
+ undef $check_at;
+ if (have_unlinked_files()) {
+ $gcf2 = new();
+ %seen = ();
+ }
+ }
+ }
+ }
}
-# we use Capitalized and ALLCAPS for compatibility with old Inline::C
-use Inline C => Config => %CFG, BOOT => 'git_libgit2_init();';
-use Inline C => $c_src;
-undef $c_src;
-undef %CFG;
-undef $lockfh;
1;