# Copyright (C) 2020-2021 all contributors # License: AGPL-3.0+ # 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 ($$) { my ($gcf2, $objdir) = @_; # libgit2 (tested 0.27.7+dfsg.1-0.2 and 0.28.3+dfsg.1-1~bpo10+1 # in Debian) doesn't handle relative epochs properly when nested # multiple levels. Add all the absolute paths to workaround it, # since $EXTINDEX_DIR/ALL.git/objects/info/alternates uses absolute # paths to reference $V2INBOX_DIR/all.git/objects and # $V2INBOX_DIR/all.git/objects/info/alternates uses relative paths # to refer to $V2INBOX_DIR/git/$EPOCH.git/objects # # See https://bugs.debian.org/975607 if (open(my $fh, '<', "$objdir/info/alternates")) { chomp(my @abs_alt = grep(m!^/!, <$fh>)); $gcf2->add_alternate($_) for @abs_alt; } $gcf2->add_alternate($objdir); 1; } # Usage: $^X -MPublicInbox::Gcf2 -e PublicInbox::Gcf2::loop # (see lib/PublicInbox/Gcf2Client.pm) sub loop () { my $gcf2 = new(); my %seen; STDERR->autoflush(1); STDOUT->autoflush(1); while () { chomp; my ($oid, $git_dir) = split(/ /, $_, 2); $seen{$git_dir} //= add_alt($gcf2, "$git_dir/objects"); if (!$gcf2->cat_oid(1, $oid)) { # retry once if missing. We only get unabbreviated OIDs # from SQLite or Xapian DBs, here, so malicious clients # can't trigger excessive retries: warn "I: $$ $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;