# -*- perl -*-
# dgit
# Debian::Dgit: functions common to dgit and its helpers and servers
#
# Copyright (C) 2015-2016 Ian Jackson
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see .
package Debian::Dgit;
use strict;
use warnings;
use Carp;
use POSIX;
use IO::Handle;
use Config;
use Digest::SHA;
use Data::Dumper;
use IPC::Open2;
use File::Path;
use File::Basename;
BEGIN {
use Exporter ();
our ($VERSION, @ISA, @EXPORT, @EXPORT_OK, %EXPORT_TAGS);
$VERSION = 1.00;
@ISA = qw(Exporter);
@EXPORT = qw(setup_sigwarn forkcheck_setup forkcheck_mainprocess
dep14_version_mangle
debiantags debiantag_old debiantag_new
server_branch server_ref
stat_exists link_ltarget
hashfile
fail ensuredir must_getcwd executable_on_path
waitstatusmsg failedcmd_waitstatus
failedcmd_report_cmd failedcmd
runcmd cmdoutput cmdoutput_errok
git_rev_parse git_cat_file
git_get_ref git_for_each_ref
git_for_each_tag_referring is_fast_fwd
$package_re $component_re $deliberately_re
$distro_re $versiontag_re $series_filename_re
$branchprefix
initdebug enabledebug enabledebuglevel
printdebug debugcmd
$debugprefix *debuglevel *DEBUG
shellquote printcmd messagequote
$negate_harmful_gitattrs
changedir git_slurp_config_src
playtree_setup);
# implicitly uses $main::us
%EXPORT_TAGS = ( policyflags => [qw(NOFFCHECK FRESHREPO NOCOMMITCHECK)],
playground => [qw(record_maindir $maindir $local_git_cfg
$maindir_gitdir $maindir_gitcommon
fresh_playground $playground
ensure_a_playground)]);
@EXPORT_OK = ( @{ $EXPORT_TAGS{policyflags} },
@{ $EXPORT_TAGS{playground} } );
}
our @EXPORT_OK;
our $package_re = '[0-9a-z][-+.0-9a-z]*';
our $component_re = '[0-9a-zA-Z][-+.0-9a-zA-Z]*';
our $deliberately_re = "(?:TEST-)?$package_re";
our $distro_re = $component_re;
our $versiontag_re = qr{[-+.\%_0-9a-zA-Z/]+};
our $branchprefix = 'dgit';
our $series_filename_re = qr{(?:^|\.)series(?!\n)$}s;
# policy hook exit status bits
# see dgit-repos-server head comment for documentation
# 1 is reserved in case something fails with `exit 1' and to spot
# dynamic loader, runtime, etc., failures, which report 127 or 255
sub NOFFCHECK () { return 0x2; }
sub FRESHREPO () { return 0x4; }
sub NOCOMMITCHECK () { return 0x8; }
our $debugprefix;
our $debuglevel = 0;
our $negate_harmful_gitattrs = "-text -eol -crlf -ident -filter";
our $forkcheck_mainprocess;
sub forkcheck_setup () {
$forkcheck_mainprocess = $$;
}
sub forkcheck_mainprocess () {
# You must have called forkcheck_setup or setup_sigwarn already
getppid != $forkcheck_mainprocess;
}
sub setup_sigwarn () {
forkcheck_setup();
$SIG{__WARN__} = sub {
die $_[0] if forkcheck_mainprocess;
};
}
sub initdebug ($) {
($debugprefix) = @_;
open DEBUG, ">/dev/null" or die $!;
}
sub enabledebug () {
open DEBUG, ">&STDERR" or die $!;
DEBUG->autoflush(1);
$debuglevel ||= 1;
}
sub enabledebuglevel ($) {
my ($newlevel) = @_; # may be undef (eg from env var)
die if $debuglevel;
$newlevel //= 0;
$newlevel += 0;
return unless $newlevel;
$debuglevel = $newlevel;
enabledebug();
}
sub printdebug {
print DEBUG $debugprefix, @_ or die $! if $debuglevel>0;
}
sub messagequote ($) {
local ($_) = @_;
s{\\}{\\\\}g;
s{\n}{\\n}g;
s{\x08}{\\b}g;
s{\t}{\\t}g;
s{[\000-\037\177]}{ sprintf "\\x%02x", ord $& }ge;
$_;
}
sub shellquote {
my @out;
local $_;
defined or confess 'internal error' foreach @_;
foreach my $a (@_) {
$_ = $a;
if (!length || m{[^-=_./:0-9a-z]}i) {
s{['\\]}{'\\$&'}g;
push @out, "'$_'";
} else {
push @out, $_;
}
}
return join ' ', @out;
}
sub printcmd {
my $fh = shift @_;
my $intro = shift @_;
print $fh $intro," " or die $!;
print $fh shellquote @_ or die $!;
print $fh "\n" or die $!;
}
sub debugcmd {
my $extraprefix = shift @_;
printcmd(\*DEBUG,$debugprefix.$extraprefix,@_) if $debuglevel>0;
}
sub dep14_version_mangle ($) {
my ($v) = @_;
# DEP-14 patch proposed 2016-11-09 "Version Mangling"
$v =~ y/~:/_%/;
$v =~ s/\.(?=\.|$|lock$)/.#/g;
return $v;
}
sub debiantag_old ($$) {
my ($v,$distro) = @_;
return "$distro/". dep14_version_mangle $v;
}
sub debiantag_new ($$) {
my ($v,$distro) = @_;
return "archive/$distro/".dep14_version_mangle $v;
}
sub debiantags ($$) {
my ($version,$distro) = @_;
map { $_->($version, $distro) } (\&debiantag_new, \&debiantag_old);
}
sub server_branch ($) { return "$branchprefix/$_[0]"; }
sub server_ref ($) { return "refs/".server_branch($_[0]); }
sub stat_exists ($) {
my ($f) = @_;
return 1 if stat $f;
return 0 if $!==&ENOENT;
die "stat $f: $!";
}
sub _us () {
$::us // ($0 =~ m#[^/]*$#, $&);
}
sub fail {
my $s = "@_\n";
$s =~ s/\n\n$/\n/;
my $prefix = _us().": ";
$s =~ s/^/$prefix/gm;
die $s;
}
sub ensuredir ($) {
my ($dir) = @_; # does not create parents
return if mkdir $dir;
return if $! == EEXIST;
die "mkdir $dir: $!";
}
sub must_getcwd () {
my $d = getcwd();
defined $d or fail "getcwd failed: $!";
return $d;
}
sub executable_on_path ($) {
my ($program) = @_;
return 1 if $program =~ m{/};
my @path = split /:/, ($ENV{PATH} // "/usr/local/bin:/bin:/usr/bin");
foreach my $pe (@path) {
my $here = "$pe/$program";
return $here if stat_exists $here && -x _;
}
return undef;
}
our @signames = split / /, $Config{sig_name};
sub waitstatusmsg () {
if (!$?) {
return "terminated, reporting successful completion";
} elsif (!($? & 255)) {
return "failed with error exit status ".WEXITSTATUS($?);
} elsif (WIFSIGNALED($?)) {
my $signum=WTERMSIG($?);
return "died due to fatal signal ".
($signames[$signum] // "number $signum").
($? & 128 ? " (core dumped)" : ""); # POSIX(3pm) has no WCOREDUMP
} else {
return "failed with unknown wait status ".$?;
}
}
sub failedcmd_report_cmd {
my $intro = shift @_;
$intro //= "failed command";
{ local ($!); printcmd \*STDERR, _us().": $intro:", @_ or die $!; };
}
sub failedcmd_waitstatus {
if ($? < 0) {
return "failed to fork/exec: $!";
} elsif ($?) {
return "subprocess ".waitstatusmsg();
} else {
return "subprocess produced invalid output";
}
}
sub failedcmd {
# Expects $!,$? as set by close - see below.
# To use with system(), set $?=-1 first.
#
# Actual behaviour of perl operations:
# success $!==0 $?==0 close of piped open
# program failed $!==0 $? >0 close of piped open
# syscall failure $! >0 $?=-1 close of piped open
# failure $! >0 unchanged close of something else
# success trashed $?==0 system
# program failed trashed $? >0 system
# syscall failure $! >0 unchanged system
failedcmd_report_cmd undef, @_;
fail failedcmd_waitstatus();
}
sub runcmd {
debugcmd "+",@_;
$!=0; $?=-1;
failedcmd @_ if system @_;
}
sub cmdoutput_errok {
confess Dumper(\@_)." ?" if grep { !defined } @_;
debugcmd "|",@_;
open P, "-|", @_ or die "$_[0] $!";
my $d;
$!=0; $?=0;
{ local $/ = undef; $d =
; }
die $! if P->error;
if (!close P) { printdebug "=>!$?\n"; return undef; }
chomp $d;
if ($debuglevel > 0) {
$d =~ m/^.*/;
my $dd = $&;
my $more = (length $' ? '...' : ''); #');
$dd =~ s{[^\n -~]|\\}{ sprintf "\\x%02x", ord $& }ge;
printdebug "=> \`$dd'",$more,"\n";
}
return $d;
}
sub cmdoutput {
my $d = cmdoutput_errok @_;
defined $d or failedcmd @_;
return $d;
}
sub link_ltarget ($$) {
my ($old,$new) = @_;
lstat $old or return undef;
if (-l _) {
$old = cmdoutput qw(realpath --), $old;
}
my $r = link $old, $new;
$r = symlink $old, $new if !$r && $!==EXDEV;
$r or die "(sym)link $old $new: $!";
}
sub hashfile ($) {
my ($fn) = @_;
my $h = Digest::SHA->new(256);
$h->addfile($fn);
return $h->hexdigest();
}
sub git_rev_parse ($) {
return cmdoutput qw(git rev-parse), "$_[0]~0";
}
sub git_cat_file ($) {
my ($objname) = @_;
# => ($type, $data) or ('missing', undef)
# in scalar context, just the data
our ($gcf_pid, $gcf_i, $gcf_o);
if (!$gcf_pid) {
my @cmd = qw(git cat-file --batch);
debugcmd "GCF|", @cmd;
$gcf_pid = open2 $gcf_o, $gcf_i, @cmd or die $!;
}
printdebug "GCF>| ", $objname, "\n";
print $gcf_i $objname, "\n" or die $!;
my $x = <$gcf_o>;
printdebug "GCF<| ", $x;
if ($x =~ m/ (missing)$/) { return ($1, undef); }
my ($type, $size) = $x =~ m/^.* (\w+) (\d+)\n/ or die "$objname ?";
my $data;
(read $gcf_o, $data, $size) == $size or die "$objname $!";
$x = <$gcf_o>;
$x eq "\n" or die "$objname ($_) $!";
return ($type, $data);
}
sub git_for_each_ref ($$;$) {
my ($pattern,$func,$gitdir) = @_;
# calls $func->($objid,$objtype,$fullrefname,$reftail);
# $reftail is RHS of ref after refs/[^/]+/
# breaks if $pattern matches any ref `refs/blah' where blah has no `/'
# $pattern may be an array ref to mean multiple patterns
$pattern = [ $pattern ] unless ref $pattern;
my @cmd = (qw(git for-each-ref), @$pattern);
if (defined $gitdir) {
@cmd = ('sh','-ec','cd "$1"; shift; exec "$@"','x', $gitdir, @cmd);
}
open GFER, "-|", @cmd or die $!;
debugcmd "|", @cmd;
while () {
chomp or die "$_ ?";
printdebug "|> ", $_, "\n";
m#^(\w+)\s+(\w+)\s+(refs/[^/]+/(\S+))$# or die "$_ ?";
$func->($1,$2,$3,$4);
}
$!=0; $?=0; close GFER or die "$pattern $? $!";
}
sub git_get_ref ($) {
# => '' if no such ref
my ($refname) = @_;
local $_ = $refname;
s{^refs/}{[r]efs/} or die "$refname $_ ?";
return cmdoutput qw(git for-each-ref --format=%(objectname)), $_;
}
sub git_for_each_tag_referring ($$) {
my ($objreferring, $func) = @_;
# calls $func->($tagobjid,$refobjid,$fullrefname,$tagname);
printdebug "git_for_each_tag_referring ",
($objreferring // 'UNDEF'),"\n";
git_for_each_ref('refs/tags', sub {
my ($tagobjid,$objtype,$fullrefname,$tagname) = @_;
return unless $objtype eq 'tag';
my $refobjid = git_rev_parse $tagobjid;
return unless
!defined $objreferring # caller wants them all
or $tagobjid eq $objreferring
or $refobjid eq $objreferring;
$func->($tagobjid,$refobjid,$fullrefname,$tagname);
});
}
sub is_fast_fwd ($$) {
my ($ancestor,$child) = @_;
my @cmd = (qw(git merge-base), $ancestor, $child);
my $mb = cmdoutput_errok @cmd;
if (defined $mb) {
return git_rev_parse($mb) eq git_rev_parse($ancestor);
} else {
$?==256 or failedcmd @cmd;
return 0;
}
}
sub changedir ($) {
my ($newdir) = @_;
printdebug "CD $newdir\n";
chdir $newdir or confess "chdir: $newdir: $!";
}
sub git_slurp_config_src ($) {
my ($src) = @_;
# returns $r such that $r->{KEY}[] = VALUE
my @cmd = (qw(git config -z --get-regexp), "--$src", qw(.*));
debugcmd "|",@cmd;
local ($debuglevel) = $debuglevel-2;
local $/="\0";
my $r = { };
open GITS, "-|", @cmd or die $!;
while () {
chomp or die;
printdebug "=> ", (messagequote $_), "\n";
m/\n/ or die "$_ ?";
push @{ $r->{$`} }, $'; #';
}
$!=0; $?=0;
close GITS
or ($!==0 && $?==256)
or failedcmd @cmd;
return $r;
}
# ========== playground handling ==========
# terminology:
#
# $maindir user's git working tree
# $playground area in .git/ where we can make files, unpack, etc. etc.
# playtree git working tree sharing object store with the user's
# inside playground, or identical to it
#
# other globals
#
# $local_git_cfg hash of arrays of values: git config from $maindir
#
# expected calling pattern
#
# firstly
#
# [record_maindir]
# must be run in directory containing .git
# assigns to $maindir if not already set
# also calls git_slurp_config_src to record git config
# in $local_git_cfg, unless it's already set
#
# fresh_playground SUBDIR_PATH_COMPONENTS
# e.g fresh_playground 'dgit/unpack' ('.git/' is implied)
# default SUBDIR_PATH_COMPONENTS is $playground_subdir
# calls record_maindir
# sets up a new playground (destroying any old one)
# assigns to $playground and returns the same pathname
# caller may call multiple times with different subdir paths
# createing different playgrounds; but $playground global can
# refer only to one, obv.
#
# ensure_a_playground SUBDIR_PATH_COMPONENTS
# like fresh_playground except:
# merely ensures the directory exists; does not delete an existing one
# never sets global $playground
#
# then can use
#
# changedir $playground
# changedir $maindir
#
# playtree_setup $local_git_cfg
# # ^ call in some (perhaps trivial) subdir of $playground
#
# rmtree $playground
# ----- maindir -----
# these three all go together
our $maindir;
our $maindir_gitdir;
our $maindir_gitcommon;
our $local_git_cfg;
sub record_maindir () {
if (!defined $maindir) {
$maindir = must_getcwd();
if (!stat "$maindir/.git") {
fail "cannot stat $maindir/.git: $!";
}
if (-d _) {
# we fall back to this in case we have a pre-worktree
# git, which may not know git rev-parse --git-common-dir
$maindir_gitdir = "$maindir/.git";
$maindir_gitcommon = "$maindir/.git";
} else {
$maindir_gitdir = cmdoutput qw(git rev-parse --git-dir);
$maindir_gitcommon = cmdoutput qw(git rev-parse --git-common-dir);
}
}
$local_git_cfg //= git_slurp_config_src 'local';
}
# ----- playgrounds -----
our $playground;
sub ensure_a_playground_parent ($) {
my ($spc) = @_;
record_maindir();
$spc = "$maindir_gitdir/$spc";
my $parent = dirname $spc;
mkdir $parent or $!==EEXIST
or fail "failed to mkdir playground parent $parent: $!";
return $spc;
}
sub ensure_a_playground ($) {
my ($spc) = @_;
$spc = ensure_a_playground_parent $spc;
mkdir $spc or $!==EEXIST or fail "failed to mkdir a playground $spc: $!";
return $spc;
}
sub fresh_playground ($) {
my ($spc) = @_;
$spc = ensure_a_playground_parent $spc;
rmtree $spc;
mkdir $spc or fail "failed to mkdir the playground $spc: $!";
return $playground = $spc;
}
# ----- playtrees -----
sub playtree_setup (;$) {
my ($t_local_git_cfg) = @_;
$t_local_git_cfg //= $local_git_cfg;
# for use in the playtree
# $maindir must be set, eg by calling record_maindir or fresh_playground
runcmd qw(git init -q);
runcmd qw(git config gc.auto 0);
foreach my $copy (qw(user.email user.name user.useConfigOnly
core.sharedRepository
core.compression core.looseCompression
core.bigFileThreshold core.fsyncObjectFiles)) {
my $v = $t_local_git_cfg->{$copy};
next unless $v;
runcmd qw(git config), $copy, $_ foreach @$v;
}
# this is confusing: we have
# . playtree, not a worktree, has .git/, our cwd
# $maindir might be a worktree so
# $maindir_gitdir contains our main working "dgit", HEAD, etc.
# $maindir_gitcommon the shared stuff, including .objects
rmtree('.git/objects');
symlink "$maindir_gitcommon/objects",'.git/objects' or die $!;
ensuredir '.git/info';
open GA, "> .git/info/attributes" or die $!;
print GA "* $negate_harmful_gitattrs\n" or die $!;
close GA or die $!;
}
1;