#!/usr/bin/perl
#
# Library functions for debhelper programs, perl version.
#
# Joey Hess, GPL copyright 1997-2008.

package Debian::Debhelper::Dh_Lib;
use strict;
use warnings;
use utf8;

use constant {
	# Lowest compat level supported
	'MIN_COMPAT_LEVEL' => 5,
	# Lowest compat level that does *not* cause deprecation
	# warnings
	'LOWEST_NON_DEPRECATED_COMPAT_LEVEL' => 9,
	# Highest compat level permitted
	'MAX_COMPAT_LEVEL' => 12,
	# Magic value for xargs
	'XARGS_INSERT_PARAMS_HERE' => \'<INSERT-HERE>', #'# Hi emacs.
	# Magic value for debhelper tools to request "current version"
	'DH_BUILTIN_VERSION' => \'<DH_LIB_VERSION>', #'# Hi emacs.
	# Default Package-Type / extension (must be aligned with dpkg)
	'DEFAULT_PACKAGE_TYPE' => 'deb',
};

use constant {
	# Package-Type / extension for dbgsym packages
	# TODO: Find a way to determine this automatically from the vendor
	#  - blocked by Dpkg::Vendor having a rather high load time (for debhelper)
	'DBGSYM_PACKAGE_TYPE' => 'ddeb',
};

use Errno qw(ENOENT EXDEV);
use Exporter qw(import);
use File::Glob qw(bsd_glob GLOB_CSH GLOB_NOMAGIC GLOB_TILDE);
our (@EXPORT, %dh);
@EXPORT = (
	# debhelper basis functionality
qw(
	init
	%dh
	compat
),
	# External command tooling API
qw(
	doit
	doit_noerror
	qx_cmd
	xargs
	XARGS_INSERT_PARAMS_HERE
	print_and_doit
	print_and_doit_noerror

	complex_doit
	escape_shell
),
	# Logging/messaging/error handling
qw(
	error
	error_exitcode
	warning
	verbose_print
	nonquiet_print
),
	# Package related actions
qw(
	getpackages
	sourcepackage
	tmpdir
	dbgsym_tmpdir
	default_sourcedir
	pkgfile
	pkgext
	pkgfilename
	package_is_arch_all
	package_binary_arch
	package_declared_arch
	package_multiarch
	package_section
	package_arch
	process_pkg
	compute_doc_main_package
	isnative
	is_udeb
),
	# File/path related actions
qw(
	basename
	dirname
	install_file
	install_prog
	install_lib
	install_dir
	install_dh_config_file
	make_symlink
	make_symlink_raw_target
	rename_path
	find_hardlinks
	rm_files
	excludefile
	is_so_or_exec_elf_file
	is_empty_dir
	reset_perm_and_owner
	log_installed_files

	filearray
	filedoublearray
	glob_expand
	glob_expand_error_handler_reject
	glob_expand_error_handler_warn_and_discard
	glob_expand_error_handler_silently_ignore

),
	# Generate triggers, substvars, maintscripts, build-time temporary files
qw(
	autoscript
	autotrigger
	addsubstvar
	delsubstvar

	generated_file
	restore_file_on_clean
),
	# Split tasks among different cores
qw(
	on_pkgs_in_parallel
	on_items_in_parallel
	on_selected_pkgs_in_parallel
),
	# R³ framework
qw(
	should_use_root
	gain_root_cmd

),
	# Architecture, cross-tooling, build options and profiles
qw(
	dpkg_architecture_value
	hostarch
	cross_command
	is_cross_compiling
	is_build_profile_active
	get_buildoption
),
	# Other
qw(
	open_gz
	get_source_date_epoch
	deprecated_functionality
),
	# Special-case functionality (e.g. tool specific), debhelper(-core) functionality and deprecated functions
qw(
	inhibit_log
	load_log
	write_log
	commit_override_log
	debhelper_script_subst
	is_make_jobserver_unavailable
	clean_jobserver_makeflags
	set_buildflags
	DEFAULT_PACKAGE_TYPE
	DBGSYM_PACKAGE_TYPE
	DH_BUILTIN_VERSION
	assert_opt_is_known_package
	restore_all_files

	buildarch
));

# The Makefile changes this if debhelper is installed in a PREFIX.
my $prefix="/usr";

my $MAX_PROCS = get_buildoption("parallel") || 1;
my $DH_TOOL_VERSION;

our $PKGNAME_REGEX = qr/[a-z0-9][-+\.a-z0-9]+/o;
our $PKGVERSION_REGEX = qr/
                 (?: \d+ : )?                # Optional epoch
                 [0-9][0-9A-Za-z.+:~]*       # Upstream version (with no hyphens)
                 (?: - [0-9A-Za-z.+:~]+ )*   # Optional debian revision (+ upstreams versions with hyphens)
                          /xoa;

sub init {
	my %params=@_;

	# Check if we can by-pass the expensive Getopt::Long by optimising for the
	# common case of "-a" or "-i"
	if (scalar(@ARGV) == 1 && ($ARGV[0] eq '-a' || $ARGV[0] eq '-i') &&
		! (defined $ENV{DH_OPTIONS} && length $ENV{DH_OPTIONS}) &&
		! (defined $ENV{DH_INTERNAL_OPTIONS} && length $ENV{DH_INTERNAL_OPTIONS})) {

		# Single -i or -a as dh does it.
		if ($ARGV[0] eq '-i') {
			push(@{$dh{DOPACKAGES}}, getpackages('indep'));
			$dh{DOINDEP} = 1;
		} else {
			push(@{$dh{DOPACKAGES}}, getpackages('arch'));
			$dh{DOARCH} = 1;
		}

		if (! @{$dh{DOPACKAGES}}) {
			if (! $dh{BLOCK_NOOP_WARNINGS}) {
				warning("You asked that all arch in(dep) packages be built, but there are none of that type.");
			}
			exit(0);
		}
		# Clear @ARGV so we do not hit the expensive case below
		@ARGV = ();
	}

	# Check to see if an option line starts with a dash,
	# or DH_OPTIONS is set.
	# If so, we need to pass this off to the resource intensive 
	# Getopt::Long, which I'd prefer to avoid loading at all if possible.
	if ((defined $ENV{DH_OPTIONS} && length $ENV{DH_OPTIONS}) ||
 	    (defined $ENV{DH_INTERNAL_OPTIONS} && length $ENV{DH_INTERNAL_OPTIONS}) ||
	    grep /^-/, @ARGV) {
		eval { require Debian::Debhelper::Dh_Getopt; };
		error($@) if $@;
		Debian::Debhelper::Dh_Getopt::parseopts(%params);
	}

	# Another way to set excludes.
	if (exists $ENV{DH_ALWAYS_EXCLUDE} && length $ENV{DH_ALWAYS_EXCLUDE}) {
		push @{$dh{EXCLUDE}}, split(":", $ENV{DH_ALWAYS_EXCLUDE});
	}
	
	# Generate EXCLUDE_FIND.
	if ($dh{EXCLUDE}) {
		$dh{EXCLUDE_FIND}='';
		foreach (@{$dh{EXCLUDE}}) {
			my $x=$_;
			$x=escape_shell($x);
			$x=~s/\./\\\\./g;
			$dh{EXCLUDE_FIND}.="-regex .\\*$x.\\* -or ";
		}
		$dh{EXCLUDE_FIND}=~s/ -or $//;
	}
	
	# Check to see if DH_VERBOSE environment variable was set, if so,
	# make sure verbose is on. Otherwise, check DH_QUIET.
	if (defined $ENV{DH_VERBOSE} && $ENV{DH_VERBOSE} ne "") {
		$dh{VERBOSE}=1;
	} elsif (defined $ENV{DH_QUIET} && $ENV{DH_QUIET} ne "") {
		$dh{QUIET}=1;
	}

	# Check to see if DH_NO_ACT environment variable was set, if so, 
	# make sure no act mode is on.
	if (defined $ENV{DH_NO_ACT} && $ENV{DH_NO_ACT} ne "") {
		$dh{NO_ACT}=1;
	}

	# Get the name of the main binary package (first one listed in
	# debian/control). Only if the main package was not set on the
	# command line.
	if (! exists $dh{MAINPACKAGE} || ! defined $dh{MAINPACKAGE}) {
		my @allpackages=getpackages();
		$dh{MAINPACKAGE}=$allpackages[0];
	}

	# Check if packages to build have been specified, if not, fall back to
	# the default, building all relevant packages.
	if (! defined $dh{DOPACKAGES} || ! @{$dh{DOPACKAGES}}) {
		push @{$dh{DOPACKAGES}}, getpackages('both');
	}

	# Check to see if -P was specified. If so, we can only act on a single
	# package.
	if ($dh{TMPDIR} && $#{$dh{DOPACKAGES}} > 0) {
		error("-P was specified, but multiple packages would be acted on (".join(",",@{$dh{DOPACKAGES}}).").");
	}

	# Figure out which package is the first one we were instructed to build.
	# This package gets special treatement: files and directories specified on
	# the command line may affect it.
	$dh{FIRSTPACKAGE}=${$dh{DOPACKAGES}}[0];

	# If no error handling function was specified, just propagate
	# errors out.
	if (! exists $dh{ERROR_HANDLER} || ! defined $dh{ERROR_HANDLER}) {
		$dh{ERROR_HANDLER}='exit 1';
	}

	$dh{U_PARAMS} //= [];
}

# Run at exit. Add the command to the log files for the packages it acted
# on, if it's exiting successfully.
my $write_log=1;
sub END {
	# If there is no 'debian/control', then we are not being run from
	# a package directory and then the write_log will not do what we
	# expect.
	return if not -f 'debian/control';
	if ($? == 0 && $write_log && (compat(9, 1) || $ENV{DH_INTERNAL_OVERRIDE})) {
		write_log(basename($0), @{$dh{DOPACKAGES}});
	}
}

sub logfile {
	my $package=shift;
	my $ext=pkgext($package);
	return "debian/${ext}debhelper.log"
}

sub add_override {
	my $line=shift;
	$line="override_$ENV{DH_INTERNAL_OVERRIDE} $line"
		if defined $ENV{DH_INTERNAL_OVERRIDE};
	return $line;
}

sub remove_override {
	my $line=shift;
	$line=~s/^\Qoverride_$ENV{DH_INTERNAL_OVERRIDE}\E\s+//
		if defined $ENV{DH_INTERNAL_OVERRIDE};
	return $line;
}

sub load_log {
	my ($package, $db)=@_;

	my @log;
	open(LOG, "<", logfile($package)) || return;
	while (<LOG>) {
		chomp;
		my $command=remove_override($_);
		push @log, $command;
		$db->{$package}{$command}=1 if defined $db;
	}
	close LOG;
	return @log;
}

sub write_log {
	my $cmd=shift;
	my @packages=@_;

	return if $dh{NO_ACT};

	foreach my $package (@packages) {
		my $log=logfile($package);
		open(LOG, ">>", $log) || error("failed to write to ${log}: $!");
		print LOG add_override($cmd)."\n";
		close LOG;
	}
}

sub commit_override_log {
	my @packages=@_;

	return if $dh{NO_ACT};

	foreach my $package (@packages) {
		my @log=map { remove_override($_) } load_log($package);
		my $log=logfile($package);
		open(LOG, ">", $log) || error("failed to write to ${log}: $!");
		print LOG $_."\n" foreach @log;
		close LOG;
	}
}

sub inhibit_log {
	$write_log=0;
}

# Pass it an array containing the arguments of a shell command like would
# be run by exec(). It turns that into a line like you might enter at the
# shell, escaping metacharacters and quoting arguments that contain spaces.
sub escape_shell {
	my @args=@_;
	my @ret;
	foreach my $word (@args) {
		if ($word=~/\s/) {
			# Escape only a few things since it will be quoted.
			# Note we use double quotes because you cannot
			# escape ' in single quotes, while " can be escaped
			# in double.
			# This does make -V"foo bar" turn into "-Vfoo bar",
			# but that will be parsed identically by the shell
			# anyway..
			$word=~s/([\n`\$"\\])/\\$1/g;
			push @ret, "\"$word\"";
		}
		else {
			# This list is from _Unix in a Nutshell_. (except '#')
			$word=~s/([\s!"\$()*+#;<>?@\[\]\\`|~])/\\$1/g;
			push @ret,$word;
		}
	}
	return join(' ', @ret);
}

# Run a command, and display the command to stdout if verbose mode is on.
# Throws error if command exits nonzero.
#
# All commands that modify files in $TMP should be run via this
# function.
#
# Note that this cannot handle complex commands, especially anything
# involving redirection. Use complex_doit instead.
sub doit {
	doit_noerror(@_) || error_exitcode(_format_cmdline(@_));
}

sub doit_noerror {
	verbose_print(_format_cmdline(@_)) if $dh{VERBOSE};

	goto \&_doit;
}

sub print_and_doit {
	print_and_doit_noerror(@_) || error_exitcode(_format_cmdline(@_));
}

sub print_and_doit_noerror {
	nonquiet_print(_format_cmdline(@_));

	goto \&_doit;
}

sub _doit {
	my (@cmd) = @_;
	my $options = ref($cmd[0]) ? shift(@cmd) : undef;
	# In compat <= 11, we warn, in compat 12 we assume people know what they are doing.
	if (not defined($options) and @cmd == 1 and compat(12) and $cmd[0] =~ m/[\s<&>|;]/) {
		deprecated_functionality('doit() + doit_*() calls will no longer spawn a shell in compat 12 for single string arguments (please use complex_doit instead)',
								 12);
		return 1 if $dh{NO_ACT};
		return system(@cmd) == 0;
	}
	return 1 if $dh{NO_ACT};
	my $pid = fork() // error("fork(): $!");
	if (not $pid) {
		if (defined($options)) {
			if (defined(my $dir = $options->{chdir})) {
				if ($dir ne '.') {
					chdir($dir) or error("chdir(\"${dir}\) failed: $!");
				}
			}
			if (defined(my $output = $options->{stdout})) {
				open(STDOUT, '>', $output) or error("redirect STDOUT failed: $!");
			}
			if (defined(my $update_env = $options->{update_env})) {
				while (my ($k, $v) = each(%{$update_env})) {
					if (defined($v)) {
						$ENV{$k} = $v;
					} else {
						delete($ENV{$k});
					}
				}
			}
		}
		# Force execvp call to avoid shell.  Apparently, even exec can
		# involve a shell if you don't do this.
		exec { $cmd[0] } @cmd;
	}
	return waitpid($pid, 0) == $pid && $? == 0;
}

sub _format_cmdline {
	my (@cmd) = @_;
	my $options = ref($cmd[0]) ? shift(@cmd) : {};
	my $cmd_line = escape_shell(@cmd);
	if (defined(my $update_env = $options->{update_env})) {
		my $need_env = 0;
		my @params;
		for my $key (sort(keys(%{$update_env}))) {
			my $value = $update_env->{$key};
			if (defined($value)) {
				my $quoted_key = escape_shell($key);
				push(@params, join('=', $quoted_key, escape_shell($value)));
				# shell does not like: "FU BAR"=1 cmd
				# if the ENV key has weird symbols, the best bet is to use env
				$need_env = 1 if $quoted_key ne $key;
			} else {
				$need_env = 1;
				push(@params, escape_shell("--unset=${key}"));
			}
		}
		unshift(@params, 'env', '--') if $need_env;
		$cmd_line = join(' ', @params, $cmd_line);
	}
	if (defined(my $dir = $options->{chdir})) {
		$cmd_line = join(' ', 'cd', escape_shell($dir), '&&', $cmd_line) if $dir ne '.';
	}
	if (defined(my $output = $options->{stdout})) {
		$cmd_line .= ' > ' . escape_shell($output);
	}
	return $cmd_line;
}

sub qx_cmd {
	my (@cmd) = @_;
	my ($output, @output);
	open(my $fd, '-|', @cmd) or error('fork+exec (' . escape_shell(@cmd) . "): $!");
	if (wantarray) {
		@output = <$fd>;
	} else {
		local $/ = undef;
		$output = <$fd>;
	}
	if (not close($fd)) {
		error("close pipe failed: $!") if $!;
		error_exitcode(escape_shell(@cmd));
	}
	return @output if wantarray;
	return $output;
}

# Run a command and display the command to stdout if verbose mode is on.
# Use doit() if you can, instead of this function, because this function
# forks a shell. However, this function can handle more complicated stuff
# like redirection.
sub complex_doit {
	verbose_print(join(" ",@_));
	
	if (! $dh{NO_ACT}) {
		# The join makes system get a scalar so it forks off a shell.
		system(join(" ", @_)) == 0 || error_exitcode(join(" ", @_))
	}			
}


sub error_exitcode {
	my $command=shift;
	if ($? == -1) {
		error("$command failed to execute: $!");
	}
	elsif ($? & 127) {
		error("$command died with signal ".($? & 127));
	}
	elsif ($?) {
		error("$command returned exit code ".($? >> 8));
	}
	else {
		warning("This tool claimed that $command have failed, but it");
		warning("appears to have returned 0.");
		error("Probably a bug in this tool is hiding the actual problem.");
	}
}

# Some shortcut functions for installing files and dirs to always
# have the same owner and mode
# install_file - installs a non-executable
# install_prog - installs an executable
# install_lib  - installs a shared library (some systems may need x-bit, others don't)
# install_dir  - installs a directory
{
	my $_loaded = 0;
	sub install_file {
		unshift(@_, 0644);
		goto \&_install_file_to_path;
	}

	sub install_prog {
		unshift(@_, 0755);
		goto \&_install_file_to_path;
	}
	sub install_lib {
		unshift(@_, 0644);
		goto \&_install_file_to_path;
	}

	sub _install_file_to_path {
		my ($mode, $source, $dest) = @_;
		if (not $_loaded) {
			$_loaded++;
			require File::Copy;
		}
		verbose_print(sprintf('install -p -m%04o %s', $mode, escape_shell($source, $dest)))
			if $dh{VERBOSE};
		return 1 if $dh{NO_ACT};
		# "install -p -mXXXX foo bar" silently discards broken
		# symlinks to install the file in place.  File::Copy does not,
		# so emulate it manually.  (#868204)
		if ( -l $dest and not -e $dest and not unlink($dest) and $! != ENOENT) {
			error("unlink $dest failed: $!");
		}
		File::Copy::copy($source, $dest) or error("copy($source, $dest): $!");
		chmod($mode, $dest) or error("chmod($mode, $dest): $!");
		my (@stat) = stat($source);
		error("stat($source): $!") if not @stat;
		utime($stat[8], $stat[9], $dest)
			or error(sprintf("utime(%d, %d, %s): $!", $stat[8] , $stat[9], $dest));
		return 1;
	}
}

{
	my $_loaded = 0;
	sub install_dir {
		my @to_create = grep { not -d $_ } @_;
		return if not @to_create;
		if (not $_loaded) {
			$_loaded++;
			require File::Path;
		}
		verbose_print(sprintf('install -d %s', escape_shell(@to_create)))
			if $dh{VERBOSE};
		return 1 if $dh{NO_ACT};
		eval {
			File::Path::make_path(@to_create, {
				# install -d uses 0755 (no umask), make_path uses 0777 (& umask) by default.
				# Since we claim to run install -d, then ensure the mode is correct.
				'chmod' => 0755,
			});
		};
		if (my $err = "$@") {
			$err =~ s/\s+at\s+\S+\s+line\s+\d+\.?\n//;
			error($err);
		}
	}
}

sub rename_path {
	my ($source, $dest) = @_;

	if ($dh{VERBOSE}) {
		my $files = escape_shell($source, $dest);
		verbose_print("mv $files");
	}
	return 1 if $dh{NO_ACT};
	if (not rename($source, $dest)) {
		my $ok = 0;
		if ($! == EXDEV) {
			# Replay with a fork+exec to handle crossing two mount
			# points (See #897569)
			$ok = _doit('mv', $source, $dest);
		}
		if (not $ok) {
			my $files = escape_shell($source, $dest);
			error("mv $files: $!");
		}
	}
	return 1;
}

sub reset_perm_and_owner {
	my ($mode, @paths) = @_;
	my $_mode;
	my $use_root = should_use_root();
	# Dark goat blood to tell 0755 from "0755"
	if (length( do { no warnings "numeric"; $mode & "" } ) ) {
		# 0755, leave it alone.
		$_mode = $mode;
	} else {
		# "0755" -> convert to 0755
		$_mode = oct($mode);
	}
	if ($dh{VERBOSE}) {
		verbose_print(sprintf('chmod %#o -- %s', $_mode, escape_shell(@paths)));
		verbose_print(sprintf('chown 0:0 -- %s', escape_shell(@paths))) if $use_root;
	}
	return if $dh{NO_ACT};
	for my $path (@paths) {
		chmod($_mode, $path) or error(sprintf('chmod(%#o, %s): %s', $mode, $path, $!));
		if ($use_root) {
			chown(0, 0, $path) or error("chown(0, 0, $path): $!");
		}
	}
}

# Run a command that may have a huge number of arguments, like xargs does.
# Pass in a reference to an array containing the arguments, and then other
# parameters that are the command and any parameters that should be passed to
# it each time.
sub xargs {
	my ($args, @static_args) = @_;

        # The kernel can accept command lines up to 20k worth of characters.
	my $command_max=20000; # LINUX SPECIFIC!!
			# (And obsolete; it's bigger now.)
			# I could use POSIX::ARG_MAX, but that would be slow.

	# Figure out length of static portion of command.
	my $static_length=0;
	my $subst_index = -1;
	for my $i (0..$#static_args) {
		my $arg = $static_args[$i];
		if ($arg eq XARGS_INSERT_PARAMS_HERE) {
			error("Only one insertion place supported in xargs, got command: @static_args") if $subst_index > -1;
			$subst_index = $i;
			next;
		}
		$static_length+=length($arg)+1;
	}
	
	my @collect=();
	my $length=$static_length;
	foreach (@$args) {
		if (length($_) + 1 + $static_length > $command_max) {
			error("This command is greater than the maximum command size allowed by the kernel, and cannot be split up further. What on earth are you doing? \"@_ $_\"");
		}
		$length+=length($_) + 1;
		if ($length < $command_max) {
			push @collect, $_;
		}
		else {
			if ($#collect > -1) {
				if ($subst_index < 0) {
					doit(@static_args, @collect);
				} else {
					my @cmd = @static_args;
					splice(@cmd, $subst_index, 1, @collect);
					doit(@cmd);
				}
			}
			@collect=($_);
			$length=$static_length + length($_) + 1;
		}
	}
	if ($#collect > -1) {
		if ($subst_index < 0) {
			doit(@static_args, @collect);
		} else {
			my @cmd = @static_args;
			splice(@cmd, $subst_index, 1, @collect);
			doit(@cmd);
		}
	}
}

# Print something if the verbose flag is on.
sub verbose_print {
	my $message=shift;
	
	if ($dh{VERBOSE}) {
		print "\t$message\n";
	}
}

# Print something unless the quiet flag is on
sub nonquiet_print {
	my $message=shift;

	if (!$dh{QUIET}) {
		print "\t$message\n";
	}
}

# Output an error message and die (can be caught).
sub error {
	my $message=shift;

	die basename($0).": $message\n";
}

# Output a warning.
sub warning {
	my $message=shift;
	
	print STDERR basename($0).": $message\n";
}

# Returns the basename of the argument passed to it.
sub basename {
	my $fn=shift;

	$fn=~s/\/$//g; # ignore trailing slashes
	$fn=~s:^.*/(.*?)$:$1:;
	return $fn;
}

# Returns the directory name of the argument passed to it.
sub dirname {
	my $fn=shift;
	
	$fn=~s/\/$//g; # ignore trailing slashes
	$fn=~s:^(.*)/.*?$:$1:;
	return $fn;
}

# Pass in a number, will return true iff the current compatibility level
# is less than or equal to that number.
my $compat_from_bd;
{
	my $warned_compat = $ENV{DH_INTERNAL_TESTSUITE_SILENT_WARNINGS} ? 1 : 0;
	my $c;

	# Used mainly for testing
	sub resetcompat {
		undef $c;
		undef $compat_from_bd;
	}

	sub compat {
		my $num=shift;
		my $nowarn=shift;

		getpackages() if not defined($compat_from_bd);
	
		if (! defined $c) {
			$c=1;
			if (-e 'debian/compat') {
				open(my $compat_in, '<', "debian/compat") || error "debian/compat: $!";
				my $l=<$compat_in>;
				close($compat_in);
				if (! defined $l || ! length $l) {
					error("debian/compat must contain a positive number (found an empty first line)");

				}
				else {
					chomp $l;
					my $new_compat = $l;
					$new_compat =~ s/^\s*+//;
					$new_compat =~ s/\s*+$//;
					if ($new_compat !~ m/^\d+$/) {
						error("debian/compat must contain a positive number (found: \"${new_compat}\")");
					}
					if (defined($compat_from_bd) and $compat_from_bd != -1) {
						warning("Please specify the debhelper compat level exactly once.");
						warning(" * debian/compat requests compat ${new_compat}.");
						warning(" * debian/control requests compat ${compat_from_bd} via \"debhelper-compat (= ${compat_from_bd})\"");
						error("debhelper compat level specified both in debian/compat and via build-dependency on debhelper-compat");
					}
					$c = $new_compat;
				}
			} elsif ($compat_from_bd != -1) {
				$c = $compat_from_bd;
			} elsif (not $nowarn) {
				error("Please specify the compatibility level in debian/compat");
			}

			if (defined $ENV{DH_COMPAT}) {
				$c=$ENV{DH_COMPAT};
			}
		}
		if (not $nowarn) {
			if ($c < MIN_COMPAT_LEVEL) {
				error("Compatibility levels before ${\MIN_COMPAT_LEVEL} are no longer supported (level $c requested)");
			}

			if ($c < LOWEST_NON_DEPRECATED_COMPAT_LEVEL && ! $warned_compat) {
				warning("Compatibility levels before ${\LOWEST_NON_DEPRECATED_COMPAT_LEVEL} are deprecated (level $c in use)");
				$warned_compat=1;
			}
	
			if ($c > MAX_COMPAT_LEVEL) {
				error("Sorry, but ${\MAX_COMPAT_LEVEL} is the highest compatibility level supported by this debhelper.");
			}
		}

		return ($c <= $num);
	}
}

# Pass it a name of a binary package, it returns the name of the tmp dir to
# use, for that package.
sub tmpdir {
	my $package=shift;

	if ($dh{TMPDIR}) {
		return $dh{TMPDIR};
	}
	else {
		return "debian/$package";
	}
}

# Pass it a name of a binary package, it returns the name of the staging dir to
# use, for that package.  (Usually debian/tmp)
sub default_sourcedir {
	my ($package) = @_;

	return 'debian/tmp';
}

# Pass this the name of a binary package, and the name of the file wanted
# for the package, and it will return the actual existing filename to use.
#
# It tries several filenames:
#   * debian/package.filename.hostarch
#   * debian/package.filename.hostos
#   * debian/package.filename
#   * debian/filename (if the package is the main package)
# If --name was specified then the files
# must have the name after the package name:
#   * debian/package.name.filename.hostarch
#   * debian/package.name.filename.hostos
#   * debian/package.name.filename
#   * debian/name.filename (if the package is the main package)

{
	my %_check_expensive;

	sub pkgfile {
		my ($package, $filename) = @_;
		my (@try, $check_expensive);

		if (not exists($_check_expensive{$filename})) {
			my @f = grep {
				!/\.debhelper$/
			} bsd_glob("debian/*.$filename.*", GLOB_CSH & ~(GLOB_NOMAGIC|GLOB_TILDE));
			if (not @f) {
				$check_expensive = 0;
			} else {
				$check_expensive = 1;
			}
			$_check_expensive{$filename} = $check_expensive;
		} else {
			$check_expensive = $_check_expensive{$filename};
		}

		# Rewrite $filename after the check_expensive globbing above
		# as $dh{NAME} is used as a prefix (so the glob above will
		# cover it).
		#
		# In practise, it should not matter as NAME is ether set
		# globally or not.  But if someone is being "clever" then the
		# cache is reusable and for the general/normal case, it has no
		# adverse effects.
		if (defined $dh{NAME}) {
			$filename="$dh{NAME}.$filename";
		}

		if (ref($package) eq 'ARRAY') {
			# !!NOT A PART OF THE PUBLIC API!!
			# Bulk test used by dh to speed up the can_skip check.   It
			# is NOT useful for finding the most precise pkgfile.
			push(@try, "debian/$filename");
			for my $pkg (@{$package}) {
				push(@try, "debian/${pkg}.${filename}");
				if ($check_expensive) {
					my $cross_type = uc(package_cross_type($pkg));
					push(@try,
						 "debian/${pkg}.${filename}.".dpkg_architecture_value("DEB_${cross_type}_ARCH"),
						 "debian/${pkg}.${filename}.".dpkg_architecture_value("DEB_${cross_type}_ARCH_OS"),
					);
				}
			}
		} else {
			# Avoid checking for hostarch+hostos unless we have reason
			# to believe that they exist.
			if ($check_expensive) {
				my $cross_type = uc(package_cross_type($package));
				push(@try,
					 "debian/${package}.${filename}.".dpkg_architecture_value("DEB_${cross_type}_ARCH"),
					 "debian/${package}.${filename}.".dpkg_architecture_value("DEB_${cross_type}_ARCH_OS"),
					);
			}
			push(@try, "debian/$package.$filename");
			if ($package eq $dh{MAINPACKAGE}) {
				push @try, "debian/$filename";
			}
		}
		foreach my $file (@try) {
			if (-f $file &&
				(! $dh{IGNORE} || ! exists $dh{IGNORE}->{$file})) {
				return $file;
			}

		}

		return "";
	}

	# Used by dh to ditch some caches that makes assumptions about
	# dh_-tools can do, which does not hold for override targets.
	sub dh_clear_unsafe_cache {
		%_check_expensive = ();
	}
}

# Pass it a name of a binary package, it returns the name to prefix to files
# in debian/ for this package.
sub pkgext {
	my ($package) = @_;
	return "$package.";
}

# Pass it the name of a binary package, it returns the name to install
# files by in eg, etc. Normally this is the same, but --name can override
# it.
sub pkgfilename {
	my $package=shift;

	if (defined $dh{NAME}) {
		return $dh{NAME};
	}
	return $package;
}

# Returns 1 if the package is a native debian package, null otherwise.
# As a side effect, sets $dh{VERSION} to the version of this package.
{
	# Caches return code so it only needs to run dpkg-parsechangelog once.
	my %isnative_cache;
	
	sub isnative {
		my $package=shift;

		return $isnative_cache{$package} if defined $isnative_cache{$package};

		if (not %isnative_cache) {
			require Dpkg::Changelog::Parse;
		}

		# Make sure we look at the correct changelog.
		my $isnative_changelog=pkgfile($package,"changelog");
		if (! $isnative_changelog) {
			$isnative_changelog="debian/changelog";
		}
		my $res = Dpkg::Changelog::Parse::changelog_parse(
			file => $isnative_changelog,
			compression => 0,
		);
		if (not defined($res)) {
			error("No changelog entries for $package!? (changelog file: ${isnative_changelog})");
		}
		my $version = $res->{'Version'};
		# Do we have a valid version?
		if (not defined($version) or not $version->is_valid) {
			error("changelog parse failure; invalid or missing version");
		}
		# Get the package version.
		$dh{VERSION} = $version->as_string;

		# Is this a native Debian package?
		if (index($dh{VERSION}, '-') > -1) {
			return $isnative_cache{$package}=0;
		}
		else {
			return $isnative_cache{$package}=1;
		}
	}
}

sub _tool_version {
	return $DH_TOOL_VERSION if defined($DH_TOOL_VERSION);
	if (defined($main::VERSION)) {
		$DH_TOOL_VERSION = $main::VERSION;
	}
	if (defined($DH_TOOL_VERSION) and $DH_TOOL_VERSION eq DH_BUILTIN_VERSION) {
		my $version = "UNRELEASED-${\MAX_COMPAT_LEVEL}";
		eval {
			require Debian::Debhelper::Dh_Version;
			$version = $Debian::Debhelper::Dh_Version::version;
		};
		$DH_TOOL_VERSION = $version;
	} else {
		$DH_TOOL_VERSION //= 'UNDECLARED';
	}
	return $DH_TOOL_VERSION;
}

# Automatically add a shell script snippet to a debian script.
# Only works if the script has #DEBHELPER# in it.
#
# Parameters:
# 1: package
# 2: script to add to
# 3: filename of snippet
# 4: either text: shell-quoted sed to run on the snippet. Ie, 's/#PACKAGE#/$PACKAGE/'
#    or a sub to run on each line of the snippet. Ie sub { s/#PACKAGE#/$PACKAGE/ }
#    or a hashref with keys being variables and values being their replacement.  Ie. { PACKAGE => $PACKAGE }
# 5: Internal usage only
sub autoscript {
	my ($package, $script, $filename, $sed, $extra_options) = @_;

	my $tool_version = _tool_version();
	# This is the file we will modify.
	my $outfile="debian/".pkgext($package)."$script.debhelper";
	if ($extra_options && exists($extra_options->{'snippet-order'})) {
		my $order = $extra_options->{'snippet-order'};
		error("Internal error - snippet order set to unknown value: \"${order}\"")
			if $order ne 'service';
		$outfile = generated_file($package, "${script}.${order}");
	}

	# Figure out what shell script snippet to use.
	my $infile;
	if (defined($ENV{DH_AUTOSCRIPTDIR}) && 
	    -e "$ENV{DH_AUTOSCRIPTDIR}/$filename") {
		$infile="$ENV{DH_AUTOSCRIPTDIR}/$filename";
	}
	else {
		if (-e "$prefix/share/debhelper/autoscripts/$filename") {
			$infile="$prefix/share/debhelper/autoscripts/$filename";
		}
		else {
			error("$prefix/share/debhelper/autoscripts/$filename does not exist");
		}
	}

	if (-e $outfile && ($script eq 'postrm' || $script eq 'prerm')
	   && !compat(5)) {
		# Add fragments to top so they run in reverse order when removing.
		if (not defined($sed) or ref($sed)) {
			verbose_print("[META] Prepend autosnippet \"$filename\" to $script [${outfile}.new]");
			if (not $dh{NO_ACT}) {
				open(my $out_fd, '>', "${outfile}.new") or error("open(${outfile}.new): $!");
				print {$out_fd} '# Automatically added by ' . basename($0) . "/${tool_version}\n";
				autoscript_sed($sed, $infile, undef, $out_fd);
				print {$out_fd} "# End automatically added section\n";
				open(my $in_fd, '<', $outfile) or error("open($outfile): $!");
				while (my $line = <$in_fd>) {
					print {$out_fd} $line;
				}
				close($in_fd);
				close($out_fd) or error("close(${outfile}.new): $!");
			}
		} else {
			complex_doit("echo \"# Automatically added by ".basename($0)."/${tool_version}\"> $outfile.new");
			autoscript_sed($sed, $infile, "$outfile.new");
			complex_doit("echo '# End automatically added section' >> $outfile.new");
			complex_doit("cat $outfile >> $outfile.new");
		}
		rename_path("${outfile}.new", $outfile);
	} elsif (not defined($sed) or ref($sed)) {
		verbose_print("[META] Append autosnippet \"$filename\" to $script [${outfile}]");
		if (not $dh{NO_ACT}) {
			open(my $out_fd, '>>', $outfile) or error("open(${outfile}): $!");
			print {$out_fd} '# Automatically added by ' . basename($0) . "/${tool_version}\n";
			autoscript_sed($sed, $infile, undef, $out_fd);
			print {$out_fd} "# End automatically added section\n";
			close($out_fd) or error("close(${outfile}): $!");
		}
	} else {
		complex_doit("echo \"# Automatically added by ".basename($0)."/${tool_version}\">> $outfile");
		autoscript_sed($sed, $infile, $outfile);
		complex_doit("echo '# End automatically added section' >> $outfile");
	}
}

sub autoscript_sed {
	my ($sed, $infile, $outfile, $out_fd) = @_;
	if (not defined($sed) or ref($sed)) {
		my $out = $out_fd;
		open(my $in, '<', $infile) or die "$infile: $!";
		if (not defined($out_fd)) {
			open($out, '>>', $outfile) or error("open($outfile): $!");
		}
		if (not defined($sed) or ref($sed) eq 'CODE') {
			while (<$in>) { $sed->() if $sed; print {$out} $_; }
		} else {
			my $rstr = sprintf('#(%s)#', join('|', reverse(sort(keys(%$sed)))));
			my $regex = qr/$rstr/;
			while (my $line = <$in>) {
				$line =~ s/$regex/$sed->{$1}/eg;
				print {$out} $line;
			}
		}
		if (not defined($out_fd)) {
			close($out) or error("close($outfile): $!");
		}
		close($in) or die "$infile: $!";
	}
	else {
		error("Internal error - passed open handle for legacy method") if defined($out_fd);
		complex_doit("sed \"$sed\" $infile >> $outfile");
	}
}

# Adds a trigger to the package
{
	my %VALID_TRIGGER_TYPES = map { $_ => 1 } qw(
		interest interest-await interest-noawait
		activate activate-await activate-noawait
	);

	sub autotrigger {
		my ($package, $trigger_type, $trigger_target) = @_;
		my ($triggers_file, $ifd, $tool_version);

		if (not exists($VALID_TRIGGER_TYPES{$trigger_type})) {
			require Carp;
			Carp::confess("Invalid/unknown trigger ${trigger_type}");
		}
		return if $dh{NO_ACT};

		$tool_version = _tool_version();
		$triggers_file = generated_file($package, 'triggers');
		if ( -f $triggers_file ) {
			open($ifd, '<', $triggers_file)
				or error("open $triggers_file failed $!");
		} else {
			open($ifd, '<', '/dev/null')
				or error("open /dev/null failed $!");
		}
		open(my $ofd, '>', "${triggers_file}.new")
			or error("open ${triggers_file}.new failed: $!");
		while (my $line = <$ifd>) {
			next if $line =~ m{\A  \Q${trigger_type}\E  \s+
                                   \Q${trigger_target}\E (?:\s|\Z)
                              }x;
			print {$ofd} $line;
		}
		print {$ofd} '# Triggers added by ' . basename($0) . "/${tool_version}\n";
		print {$ofd} "${trigger_type} ${trigger_target}\n";
		close($ofd) or error("closing ${triggers_file}.new failed: $!");
		close($ifd);
		rename_path("${triggers_file}.new", $triggers_file);
	}
}

# Generated files are cleaned by dh_clean AND dh_prep
# - Package can be set to "_source" to generate a file relevant
#   for the source package (the meson build does this atm.).
#   Files for "_source" are only cleaned by dh_clean.
sub generated_file {
	my ($package, $filename, $mkdirs) = @_;
	my $dir = "debian/.debhelper/generated/${package}";
	my $path = "${dir}/${filename}";
	$mkdirs //= 1;
	install_dir($dir) if $mkdirs;
	return $path;
}

# Removes a whole substvar line.
sub delsubstvar {
	my $package=shift;
	my $substvar=shift;

	my $ext=pkgext($package);
	my $substvarfile="debian/${ext}substvars";

	if (-e $substvarfile) {
		complex_doit("grep -a -s -v '^${substvar}=' $substvarfile > $substvarfile.new || true");
		rename_path("${substvarfile}.new", $substvarfile);
	}
}
				
# Adds a dependency on some package to the specified
# substvar in a package's substvar's file.
sub addsubstvar {
	my $package=shift;
	my $substvar=shift;
	my $deppackage=shift;
	my $verinfo=shift;
	my $remove=shift;

	my $ext=pkgext($package);
	my $substvarfile="debian/${ext}substvars";
	my $str=$deppackage;
	$str.=" ($verinfo)" if defined $verinfo && length $verinfo;

	# Figure out what the line will look like, based on what's there
	# now, and what we're to add or remove.
	my $line="";
	if (-e $substvarfile) {
		my %items;
		open(my $in, '<', $substvarfile) || error "read $substvarfile: $!";
		while (<$in>) {
			chomp;
			if (/^\Q$substvar\E=(.*)/) {
				%items = map { $_ => 1} split(", ", $1);
				
				last;
			}
		}
		close($in);
		if (! $remove) {
			$items{$str}=1;
		}
		else {
			delete $items{$str};
		}
		$line=join(", ", sort keys %items);
	}
	elsif (! $remove) {
		$line=$str;
	}

	if (length $line) {
		complex_doit("(grep -a -s -v ${substvar} $substvarfile; echo ".escape_shell("${substvar}=$line").") > $substvarfile.new");
		rename_path("$substvarfile.new", $substvarfile);
	}
	else {
		delsubstvar($package,$substvar);
	}
}

sub _glob_expand_error_default_msg {
	my ($pattern, $dir_ref) = @_;
	my $dir_list = join(', ', map { escape_shell($_) } @{$dir_ref});
	return "Cannot find (any matches for) \"${pattern}\" (tried in $dir_list)";
}

sub glob_expand_error_handler_reject {
	my $msg = _glob_expand_error_default_msg(@_);
	error("$msg\n");
	return;
}

sub glob_expand_error_handler_warn_and_discard {
	my $msg = _glob_expand_error_default_msg(@_);
	warning("$msg\n");
	return;
}

sub glob_expand_error_handler_silently_ignore {
	return;
}

sub glob_expand {
	my ($dir_ref, $error_handler, @patterns) = @_;
	my @dirs = @{$dir_ref};
	my @result;
	for my $pattern (@patterns) {
		my @m;
		for my $dir (@dirs) {
			my $full_pattern = "$dir/$pattern";
			@m = bsd_glob($full_pattern, GLOB_CSH & ~(GLOB_NOMAGIC|GLOB_TILDE));
			last if @m;
			# Handle "foo{bar}" pattern (#888251)
			if (-l $full_pattern or -e _) {
				push(@m, $full_pattern);
				last;
			}
		}
		if (not @m) {
			$error_handler //= \&glob_expand_error_handler_reject;
			$error_handler->($pattern, $dir_ref);
		}
		push(@result, @m);
	}
	return @result;
}

# Reads in the specified file, one line at a time. splits on words, 
# and returns an array of arrays of the contents.
# If a value is passed in as the second parameter, then glob
# expansion is done in the directory specified by the parameter ("." is
# frequently a good choice).
sub filedoublearray {
	my ($file, $globdir, $error_handler) = @_;

	# executable config files are a v9 thing.
	my $x=! compat(8) && -x $file;
	if ($x) {
		require Cwd;
		my $cmd=Cwd::abs_path($file);
		$ENV{"DH_CONFIG_ACT_ON_PACKAGES"} = join(",", @{$dh{"DOPACKAGES"}});
		open (DH_FARRAY_IN, "$cmd |") || error("cannot run $file: $!");
		delete $ENV{"DH_CONFIG_ACT_ON_PACKAGES"};
	}
	else {
		open (DH_FARRAY_IN, '<', $file) || error("cannot read $file: $!");
	}

	my @ret;
	while (<DH_FARRAY_IN>) {
		chomp;
		if (not $x)  {
			next if /^#/ || /^$/;
		}
		my @line;

		if (defined($globdir) && ! $x) {
			if (ref($globdir)) {
				my @patterns = split;
				push(@line, glob_expand($globdir, $error_handler, @patterns));
			} else {
				# Legacy call - Silently discards globs that match nothing.
				#
				# The tricky bit is that the glob expansion is done
				# as if we were in the specified directory, so the
				# filenames that come out are relative to it.
				foreach (map { glob "$globdir/$_" } split) {
					s#^$globdir/##;
					push @line, $_;
				}
			}
		}
		else {
			@line = split;
		}
		push @ret, [@line];
	}

	if (!close(DH_FARRAY_IN)) {
		if ($x) {
			error("Error closing fd/process for $file: $!") if $!;
			error_exitcode("$file (executable config)");
		} else {
			error("problem reading $file: $!");
		}
	}
	
	return @ret;
}

# Reads in the specified file, one word at a time, and returns an array of
# the result. Can do globbing as does filedoublearray.
sub filearray {
	return map { @$_ } filedoublearray(@_);
}

# Passed a filename, returns true if -X says that file should be excluded.
sub excludefile {
        my $filename = shift;
        foreach my $f (@{$dh{EXCLUDE}}) {
                return 1 if $filename =~ /\Q$f\E/;
        }
        return 0;
}

{
	my %dpkg_arch_output;
	sub dpkg_architecture_value {
		my $var = shift;
		if (exists($ENV{$var})) {
			my $value = $ENV{$var};
			return $value if $value ne q{};
			warning("ENV[$var] is set to the empty string.  It has been ignored to avoid bugs like #862842");
			delete($ENV{$var});
		}
		if (! exists($dpkg_arch_output{$var})) {
			# Return here if we already consulted dpkg-architecture
			# (saves a fork+exec on unknown variables)
			return if %dpkg_arch_output;

			open(my $fd, '-|', 'dpkg-architecture')
				or error("dpkg-architecture failed");
			while (my $line = <$fd>) {
				chomp($line);
				my ($k, $v) = split(/=/, $line, 2);
				$dpkg_arch_output{$k} = $v;
			}
			close($fd);
		}
		return $dpkg_arch_output{$var};
	}
}

# Confusing name for hostarch
sub buildarch {
	deprecated_functionality('buildarch() is deprecated and replaced by hostarch()', 12);
	goto \&hostarch;
}

# Returns the architecture that will run binaries produced (DEB_HOST_ARCH)
sub hostarch {
	dpkg_architecture_value('DEB_HOST_ARCH');
}

# Returns a truth value if this seems to be a cross-compile
sub is_cross_compiling {
	return dpkg_architecture_value("DEB_BUILD_GNU_TYPE")
	    ne dpkg_architecture_value("DEB_HOST_GNU_TYPE");
}

# Passed an arch and a list of arches to match against, returns true if matched
{
	my %knownsame;

	sub samearch {
		my $arch=shift;
		my @archlist=split(/\s+/,shift);
	
		foreach my $a (@archlist) {
			if (exists $knownsame{$arch}{$a}) {
				return 1 if $knownsame{$arch}{$a};
				next;
			}

			require Dpkg::Arch;
			if (Dpkg::Arch::debarch_is($arch, $a)) {
				return $knownsame{$arch}{$a}=1;
			}
			else {
				$knownsame{$arch}{$a}=0;
			}
		}
	
		return 0;
	}
}



# Returns a list of packages in the control file.
# Pass "arch" or "indep" to specify arch-dependent (that will be built
# for the system's arch) or independent. If nothing is specified,
# returns all packages. Also, "both" returns the union of "arch" and "indep"
# packages.
#
# As a side effect, populates %package_arches and %package_types
# with the types of all packages (not only those returned).
my (%package_types, %package_arches, %package_multiarches, %packages_by_type,
    %package_sections, $sourcepackage, %package_cross_type);

# Resets the arrays; used mostly for testing
sub resetpackages {
	undef $sourcepackage;
	%package_types = %package_arches = %package_multiarches =
	    %packages_by_type = %package_sections = %package_cross_type = ();
}

# Returns source package name
sub sourcepackage {
	getpackages() if not defined($sourcepackage);
	return $sourcepackage;
}

sub getpackages {
	my ($type) = @_;
	error("getpackages: First argument must be one of \"arch\", \"indep\", or \"both\"")
		if defined($type) and $type ne 'both' and $type ne 'indep' and $type ne 'arch';

	$type //= 'all-listed-in-control-file';

	if (%packages_by_type) {
		return @{$packages_by_type{$type}};
	}

	my $fd;
	my $package="";
	my $arch="";
	my $section="";
	my ($package_type, $multiarch, %seen, @profiles, $source_section,
		$included_in_build_profile, $cross_type, $cross_target_arch,
		%bd_fields, $bd_field_value);
	if (exists $ENV{'DEB_BUILD_PROFILES'}) {
		@profiles=split /\s+/, $ENV{'DEB_BUILD_PROFILES'};
	}
	if (not open($fd, '<', 'debian/control')) {
		error("\"debian/control\" not found. Are you sure you are in the correct directory?")
			if $! == ENOENT;
		error("cannot read debian/control: $!\n");
	};

	$packages_by_type{$_} = [] for qw(both indep arch all-listed-in-control-file);
	while (<$fd>) {
		chomp;
		s/\s+$//;
		next if m/^\s*+\#/;

		if (/^Source:\s*+(.*)/i) {
			$sourcepackage = $1;
			$bd_field_value = undef;
			next;
		} elsif (/^Section:\s*+(.*)$/i) {
			$source_section = $1;
			$bd_field_value = undef;
			next;
		} elsif (/^(Build-Depends(?:-Arch|-Indep)?):\s*+(.*)$/i) {
			my ($field, $value) = (lc($1), $2);
			$bd_field_value = [$value];
			$bd_fields{$field} = $bd_field_value;
		} elsif (/^\S/) {
			$bd_field_value = undef;
		} elsif (/^\s/ and $bd_field_value) {
			push(@{$bd_field_value}, $_);
		}
		next if not $_ and not defined($sourcepackage);
		last if (!$_ or eof); # end of stanza.
	}
	error("could not find Source: line in control file.") if not defined($sourcepackage);
	if (%bd_fields) {
		my ($dh_compat_bd, $final_level);
		for my $field (sort(keys(%bd_fields))) {
			my $value = join(' ', @{$bd_fields{$field}});
			$value =~ s/^\s*//;
			$value =~ s/\s*(?:,\s*)?$//;
			for my $dep (split(/\s*,\s*/, $value)) {
				if ($dep =~ m/^debhelper-compat\s*[(]\s*=\s*(${PKGVERSION_REGEX})\s*[)]$/) {
					my $version = $1;
					if ($version =~m/^(\d+)\D.*$/) {
						my $guessed_compat = $1;
						warning("Please use the compat level as the exact version rather than the full version.");
						warning("  Perhaps you meant: debhelper-compat (= ${guessed_compat})");
						if ($field ne 'build-depends') {
							warning(" * Also, please move the declaration to Build-Depends (it was found in ${field})");
						}
						error("Invalid compat level ${version}, derived from relation: ${dep}");
					}
					$final_level = $version;
					error("Duplicate debhelper-compat build-dependency: ${dh_compat_bd} vs. ${dep}") if $dh_compat_bd;
					error("The debhelper-compat build-dependency must be in the Build-Depends field (not $field)")
						if $field ne 'build-depends';
					$dh_compat_bd = $dep;
				} elsif ($dep =~ m/^debhelper-compat\s*(?:\S.*)?$/) {
					my $clevel = "${\MAX_COMPAT_LEVEL}";
					eval {
						require Debian::Debhelper::Dh_Version;
						$clevel = $Debian::Debhelper::Dh_Version::version;
					};
					$clevel =~ s/^\d+\K\D.*$//;
					warning("Found invalid debhelper-compat relation: ${dep}");
					warning(" * Please format the relation as (example): debhelper-compat (= ${clevel})");
					warning(" * Note that alternatives, architecture restrictions, build-profiles etc. are not supported.");
					if ($field ne 'build-depends') {
						warning(" * Also, please move the declaration to Build-Depends (it was found in ${field})");
					}
					warning(" * If this is not possible, then please remove the debhelper-compat relation and insert the");
					warning("   compat level into the file debian/compat.  (E.g. \"echo ${clevel} > debian/compat\")");
					error("Could not parse desired debhelper compat level from relation: $dep");
				}
			}
		}
		$compat_from_bd = $final_level // -1;
	} else {
		$compat_from_bd = -1;
	}

	while (<$fd>) {
		chomp;
		s/\s+$//;
		if (/^Package:\s*+(.*)/i) {
			$package=$1;
			# Detect duplicate package names in the same control file.
			if (! $seen{$package}) {
				$seen{$package}=1;
			}
			else {
				error("debian/control has a duplicate entry for $package");
			}
			$included_in_build_profile=1;
		} elsif (/^Section:\s*+(.*)$/i) {
			$section = $1;
		} elsif (/^Architecture:\s*+(.*)/i) {
			$arch=$1;
		} elsif (/^(?:X[BC]*-)?Package-Type:\s*+(.*)/i) {
			$package_type=$1;
		} elsif (/^Multi-Arch:\s*(.*)/i) {
			$multiarch = $1;
		} elsif (/^X-DH-Build-For-Type:\s*+(.*)/i) {
			$cross_type = $1;
			if ($cross_type ne 'host' and $cross_type ne 'target') {
				error("Unknown value of X-DH-Build-For-Type \"$cross_type\" at debian/control:$.");
			}
		} elsif (/^Build-Profiles:\s*+(.*)/i) {
			# rely on libdpkg-perl providing the parsing functions
			# because if we work on a package with a Build-Profiles
			# field, then a high enough version of dpkg-dev is needed
			# anyways
			my $build_profiles=$1;
			eval {
				require Dpkg::BuildProfiles;
				my @restrictions=Dpkg::BuildProfiles::parse_build_profiles($build_profiles);
				if (@restrictions) {
					$included_in_build_profile=Dpkg::BuildProfiles::evaluate_restriction_formula(\@restrictions, \@profiles);
				}
			};
			if ($@) {
				error("The control file has a Build-Profiles field. Requires libdpkg-perl >= 1.17.14");
			}
		}

		if (!$_ or eof) { # end of stanza.
			if ($package) {
				$package_types{$package}=$package_type // 'deb';
				$package_arches{$package}=$arch;
				$package_multiarches{$package} = $multiarch;
				$package_sections{$package} = $section || $source_section;
				$cross_type //= 'host';
				$package_cross_type{$package} = $cross_type;
				push(@{$packages_by_type{'all-listed-in-control-file'}}, $package);
				if ($included_in_build_profile) {
					if ($arch eq 'all') {
						push(@{$packages_by_type{'indep'}}, $package);
						push(@{$packages_by_type{'both'}}, $package);
					} else {
						my $included = 0;
						$included = 1 if $arch eq 'any';
						if (not $included) {
							my $desired_arch = hostarch();
							if ($cross_type eq 'target') {
								$cross_target_arch //= dpkg_architecture_value('DEB_TARGET_ARCH');
								$desired_arch = $cross_target_arch;
							}
							$included = 1 if samearch($desired_arch, $arch);
						}
						if ($included) {
							push(@{$packages_by_type{'arch'}}, $package);
							push(@{$packages_by_type{'both'}}, $package);
						}
					}
				}
			}
			$package='';
			$package_type=undef;
			$cross_type = undef;
			$arch='';
			$section='';
		}
	}
	close($fd);

	return @{$packages_by_type{$type}};
}

# Return true if we should use root.
# - Takes an optional keyword; if passed, this will return true if the keyword is listed in R^3 (Rules-Requires-Root)
# - If the optional keyword is omitted or not present in R^3 and R^3 is not 'binary-targets', then returns false
# - Returns true otherwise (i.e. keyword is in R^3 or R^3 is 'binary-targets')
{
	my %rrr;
	sub should_use_root {
		my ($keyword) = @_;
		my $rrr_env = $ENV{'DEB_RULES_REQUIRES_ROOT'} // 'binary-targets';
		$rrr_env =~ s/^\s++//;
		$rrr_env =~ s/\s++$//;
		return 0 if $rrr_env eq 'no';
		return 1 if $rrr_env eq 'binary-targets';
		return 0 if not defined($keyword);

		%rrr = map { $_ => 1 } split(' ', $rrr_env) if not %rrr;
		return 1 if exists($rrr{$keyword});
		return 0;
	}
}

# Returns the "gain root command" as a list suitable for passing as a part of the command to "doit()"
sub gain_root_cmd {
	my $raw_cmd = $ENV{DEB_GAIN_ROOT_CMD};
	return if not defined($raw_cmd) or $raw_cmd =~ m/^\s*+$/;
	return split(' ', $raw_cmd);
}

sub root_requirements {
	my $rrr_env = $ENV{'DEB_RULES_REQUIRES_ROOT'} // 'binary-targets';
	$rrr_env =~ s/^\s++//;
	$rrr_env =~ s/\s++$//;
	return 'none' if $rrr_env eq 'no';
	return 'legacy-root' if $rrr_env eq 'binary-targets';
	return 'targeted-promotion';
}

# Returns the arch a package will build for.
#
# Deprecated: please switch to the more descriptive
# package_binary_arch function instead.
sub package_arch {
	my $package=shift;
	return package_binary_arch($package);
}

# Returns the architecture going into the resulting .deb, i.e. the
# host architecture or "all".
sub package_binary_arch {
	my $package=shift;

	if (! exists $package_arches{$package}) {
		warning "package $package is not in control info";
		return hostarch();
	}
	return 'all' if $package_arches{$package} eq 'all';
	return dpkg_architecture_value('DEB_TARGET_ARCH') if package_cross_type($package) eq 'target';
	return hostarch();
}

# Returns the Architecture: value which the package declared.
sub package_declared_arch {
	my $package=shift;

	if (! exists $package_arches{$package}) {
		warning "package $package is not in control info";
		return hostarch();
	}
	return $package_arches{$package};
}

# Returns whether the package specified Architecture: all
sub package_is_arch_all {
	my $package=shift;

	if (! exists $package_arches{$package}) {
		warning "package $package is not in control info";
		return hostarch();
	}
	return $package_arches{$package} eq 'all';
}

# Returns the multiarch value of a package.
sub package_multiarch {
	my $package=shift;

	# Test the architecture field instead, as it is common for a
	# package to not have a multi-arch value.
	if (! exists $package_arches{$package}) {
		warning "package $package is not in control info";
		# The only sane default
		return 'no';
	}
	return $package_multiarches{$package} // 'no';
}

# Returns the (raw) section value of a package (possibly including component).
sub package_section {
	my ($package) = @_;

	# Test the architecture field instead, as it is common for a
	# package to not have a multi-arch value.
	if (! exists $package_sections{$package}) {
		warning "package $package is not in control info";
		return 'unknown';
	}
	return $package_sections{$package} // 'unknown';
}

sub package_cross_type {
	my ($package) = @_;

	# Test the architecture field instead, as it is common for a
	# package to not have a multi-arch value.
	if (! exists $package_cross_type{$package}) {
		warning "package $package is not in control info";
		return 'host';
	}
	return $package_cross_type{$package} // 'host';
}

# Return true if a given package is really a udeb.
sub is_udeb {
	my $package=shift;
	
	if (! exists $package_types{$package}) {
		warning "package $package is not in control info";
		return 0;
	}
	return $package_types{$package} eq 'udeb';
}

{
	my %packages_to_process;

	sub process_pkg {
		my ($package) = @_;
		if (not %packages_to_process) {
			%packages_to_process = map { $_ => 1 } @{$dh{DOPACKAGES}};
		}
		return $packages_to_process{$package} // 0;
	}
}

sub _concat_slurp_script_files {
	my (@files) = @_;
	my $res = '';
	for my $file (@files) {
		open(my $fd, '<', $file) or error("open($file) failed: $!");
		my $f = join('', <$fd>);
		close($fd);
		$res .= $f;
	}
	return $res;
}

# Handles #DEBHELPER# substitution in a script; also can generate a new
# script from scratch if none exists but there is a .debhelper file for it.
sub debhelper_script_subst {
	my $package=shift;
	my $script=shift;
	
	my $tmp=tmpdir($package);
	my $ext=pkgext($package);
	my $file=pkgfile($package,$script);
	my $service_script = generated_file($package, "${script}.service", 0);
	my @generated_scripts = ("debian/$ext$script.debhelper", $service_script);
	if ($script eq 'prerm' or $script eq 'postrm') {
		@generated_scripts = reverse(@generated_scripts);
	}
	@generated_scripts = grep { -f } @generated_scripts;

	if ($file ne '') {
		if (@generated_scripts) {
			if ($dh{VERBOSE}) {
				verbose_print('cp -f ' . escape_shell($file) . " $tmp/DEBIAN/$script");
				verbose_print("perl -p -i -e \"s~#DEBHELPER#~qx{cat @generated_scripts}~eg\" $tmp/DEBIAN/$script");
			}
			# Add this into the script, where it has #DEBHELPER#
			my $text = _concat_slurp_script_files(@generated_scripts);
			if (not $dh{NO_ACT}) {
				open(my $out_fd, '>', "$tmp/DEBIAN/$script") or error("open($tmp/DEBIAN/$script) failed: $!");
				open(my $in_fd, '<', $file) or error("open($file) failed: $!");
				while (my $line = <$in_fd>) {
					$line =~ s/#DEBHELPER#/$text/g;
					print {$out_fd} $line;
				}
				close($in_fd);
				close($out_fd) or error("close($tmp/DEBIAN/$script) failed: $!");
			}
		} else {
			# Just get rid of any #DEBHELPER# in the script.
			doit({ stdout => "$tmp/DEBIAN/$script" }, 'sed', 's/#DEBHELPER#//', $file);
		}
		reset_perm_and_owner('0755', "$tmp/DEBIAN/$script");
	}
	elsif (@generated_scripts) {
		if ($dh{VERBOSE}) {
			verbose_print(q{printf '#!/bin/sh\nset -e\n' > } . "$tmp/DEBIAN/$script");
			verbose_print("cat @generated_scripts >> $tmp/DEBIAN/$script");
		}
		if (not $dh{NO_ACT}) {
			open(my $out_fd, '>', "$tmp/DEBIAN/$script") or error("open($tmp/DEBIAN/$script): $!");
			print {$out_fd} "#!/bin/sh\n";
			print {$out_fd} "set -e\n";
			for my $generated_script (@generated_scripts) {
				open(my $in_fd, '<', $generated_script)
					or error("open($generated_script) failed: $!");
				while (my $line = <$in_fd>) {
					print {$out_fd} $line;
				}
				close($in_fd);
			}
			close($out_fd) or error("close($tmp/DEBIAN/$script) failed: $!");
		}
		reset_perm_and_owner('0755', "$tmp/DEBIAN/$script");
	}
}

sub rm_files {
	my @files = @_;
	verbose_print('rm -f ' . escape_shell(@files))
		if $dh{VERBOSE};
	return 1 if $dh{NO_ACT};
	for my $file (@files) {
		if (not unlink($file) and $! != ENOENT) {
			error("unlink $file failed: $!");
		}
	}
	return 1;
}

sub make_symlink_raw_target {
	my ($src, $dest) = @_;
	verbose_print('ln -s ' . escape_shell($src, $dest))
		if $dh{VERBOSE};
	return 1 if $dh{NO_ACT};
	if (not symlink($src, $dest)) {
		error("symlink($src, $dest) failed: $!");
	}
	return 1;
}

# make_symlink($dest, $src[, $tmp]) creates a symlink from  $dest -> $src.
# if $tmp is given, $dest will be created within it.
# Usually $tmp should be the value of tmpdir($package);
sub make_symlink{
	my $dest = shift;
	my $src = _expand_path(shift);
	my $tmp = shift;
	$tmp = '' if not defined($tmp);

	if ($dest =~ m{(?:^|/)*[.]{2}(?:/|$)}) {
		error("Invalid destination/link name (contains \"..\"-segments): $dest");
	}

	$src =~ s{^(?:[.]/+)++}{};
	$dest =~ s{^(?:[.]/+)++}{};

	$src=~s:^/++::;
	$dest=~s:^/++::;

	if ($src eq $dest) {
		warning("skipping link from $src to self");
		return;
	}



	# Policy says that if the link is all within one toplevel
	# directory, it should be relative. If it's between
	# top level directories, leave it absolute.
	my @src_dirs = grep { $_ ne '.' } split(m:/+:,$src);
	my @dest_dirs = grep { $_ ne '.' } split(m:/+:,$dest);
	if (@src_dirs > 0 && $src_dirs[0] eq $dest_dirs[0]) {
		# Figure out how much of a path $src and $dest
		# share in common.
		my $x;
		for ($x=0; $x < @src_dirs && $src_dirs[$x] eq $dest_dirs[$x]; $x++) {}
		# Build up the new src.
		$src="";
		for (1..$#dest_dirs - $x) {
			$src.="../";
		}
		for ($x .. $#src_dirs) {
			$src.=$src_dirs[$_]."/";
		}
		if ($x > $#src_dirs && ! length $src) {
			$src="."; # special case
		}
		$src=~s:/$::;
	}
	else {
		# Make sure it's properly absolute.
		$src="/$src";
	}

	my $full_dest = "$tmp/$dest";
	if ( -l $full_dest ) {
		# All ok - we can always replace a link, and target directory must exists
	} elsif (-d _) {
		# We cannot replace a directory though
		error("link destination $full_dest is a directory");
	} else {
		# Make sure the directory the link will be in exists.
		my $basedir=dirname($full_dest);
		install_dir($basedir);
	}
	rm_files($full_dest);
	make_symlink_raw_target($src, $full_dest);
}

# _expand_path expands all path "." and ".." components, but doesn't
# resolve symbolic links.
sub _expand_path {
	my $start = @_ ? shift : '.';
	my @pathname = split(m:/+:,$start);
	my @respath;
	for my $entry (@pathname) {
		if ($entry eq '.' || $entry eq '') {
			# Do nothing
		}
		elsif ($entry eq '..') {
			if ($#respath == -1) {
				# Do nothing
			}
			else {
				pop @respath;
			}
		}
		else {
			push @respath, $entry;
		}
	}

	my $result;
	for my $entry (@respath) {
		$result .= '/' . $entry;
	}
	if (! defined $result) {
		$result="/"; # special case
	}
	return $result;
}

# Checks if make's jobserver is enabled via MAKEFLAGS, but
# the FD used to communicate with it is actually not available.
sub is_make_jobserver_unavailable {
	if (exists $ENV{MAKEFLAGS} && 
	    $ENV{MAKEFLAGS} =~ /(?:^|\s)--jobserver-(?:fds|auth)=(\d+)/) {
		if (!open(my $in, "<&$1")) {
			return 1; # unavailable
		}
		else {
			close $in;
			return 0; # available
		}
	}

	return; # no jobserver specified
}

# Cleans out jobserver options from MAKEFLAGS.
sub clean_jobserver_makeflags {
	if (exists $ENV{MAKEFLAGS}) {
		if ($ENV{MAKEFLAGS} =~ /(?:^|\s)--jobserver-(?:fds|auth)=\d+/) {
			$ENV{MAKEFLAGS} =~ s/(?:^|\s)--jobserver-(?:fds|auth)=\S+//g;
			$ENV{MAKEFLAGS} =~ s/(?:^|\s)-j\b//g;
		}
		delete $ENV{MAKEFLAGS} if $ENV{MAKEFLAGS} =~ /^\s*$/;
	}
}

# If cross-compiling, returns appropriate cross version of command.
sub cross_command {
	my ($package, $command) = @_;
	if (package_cross_type($package) eq 'target') {
		if (dpkg_architecture_value("DEB_HOST_GNU_TYPE") ne dpkg_architecture_value("DEB_TARGET_GNU_TYPE")) {
			return dpkg_architecture_value("DEB_TARGET_GNU_TYPE") . "-$command";
		}
	}
	if (is_cross_compiling()) {
		return dpkg_architecture_value("DEB_HOST_GNU_TYPE")."-$command";
	}
	else {
		return $command;
	}
}

# Returns the SOURCE_DATE_EPOCH ENV variable if set OR computes it
# from the latest changelog entry, sets the SOURCE_DATE_EPOCH ENV
# variable and returns the computed value.
sub get_source_date_epoch {
	return $ENV{SOURCE_DATE_EPOCH} if exists($ENV{SOURCE_DATE_EPOCH});
	eval { require Dpkg::Changelog::Debian };
	if ($@) {
		warning "unable to set SOURCE_DATE_EPOCH: $@";
		return;
	}
	eval { require Time::Piece };
	if ($@) {
		warning "unable to set SOURCE_DATE_EPOCH: $@";
		return;
	}

	my $changelog = Dpkg::Changelog::Debian->new(range => {"count" => 1});
	$changelog->load("debian/changelog");

	my $tt = @{$changelog}[0]->get_timestamp();
	$tt =~ s/\s*\([^\)]+\)\s*$//; # Remove the optional timezone codename
	my $timestamp = Time::Piece->strptime($tt, "%a, %d %b %Y %T %z");

	return $ENV{SOURCE_DATE_EPOCH} = $timestamp->epoch();
}

# Sets environment variables from dpkg-buildflags. Avoids changing
# any existing environment variables.
sub set_buildflags {
	return if $ENV{DH_INTERNAL_BUILDFLAGS};
	$ENV{DH_INTERNAL_BUILDFLAGS}=1;

	# For the side effect of computing the SOURCE_DATE_EPOCH variable.
	get_source_date_epoch();

	return if compat(8);

	# Export PERL_USE_UNSAFE_INC as a transitional step to allow us
	# to remove . from @INC by default without breaking packages which
	# rely on this [CVE-2016-1238]
	$ENV{PERL_USE_UNSAFE_INC} = 1 if compat(10);

	eval { require Dpkg::BuildFlags };
	if ($@) {
		warning "unable to load build flags: $@";
		return;
	}

	my $buildflags = Dpkg::BuildFlags->new();
	$buildflags->load_config();
	foreach my $flag ($buildflags->list()) {
		next unless $flag =~ /^[A-Z]/; # Skip flags starting with lowercase
		if (! exists $ENV{$flag}) {
			$ENV{$flag} = $buildflags->get($flag);
		}
	}
}

# Gets a DEB_BUILD_OPTIONS option, if set.
sub get_buildoption {
	my $wanted=shift;

	return undef unless exists $ENV{DEB_BUILD_OPTIONS};

	foreach my $opt (split(/\s+/, $ENV{DEB_BUILD_OPTIONS})) {
		# currently parallel= is the only one with a parameter
		if ($opt =~ /^parallel=(-?\d+)$/ && $wanted eq 'parallel') {
			return $1;
		}
		elsif ($opt eq $wanted) {
			return 1;
		}
	}
	return undef;
}

# Returns true if DEB_BUILD_PROFILES lists the given profile.
sub is_build_profile_active {
	my ($wanted) = @_;
	return 0 if not exists($ENV{DEB_BUILD_PROFILES});
	for my $prof (split(m/\s+/, $ENV{DEB_BUILD_PROFILES})) {
		return 1 if $prof eq $wanted;
	}
	return 0;
}

# install a dh config file (e.g. debian/<pkg>.lintian-overrides) into
# the package.  Under compat 9+ it may execute the file and use its
# output instead.
#
# install_dh_config_file(SOURCE, TARGET[, MODE])
sub install_dh_config_file {
	my ($source, $target, $mode) = @_;
	$mode = 0644 if not defined($mode);

	if (!compat(8) and -x $source) {
		my @sstat = stat(_) || error("cannot stat $source: $!");
		open(my $tfd, '>', $target) || error("cannot open $target: $!");
		chmod($mode, $tfd) || error("cannot chmod $target: $!");
		open(my $sfd, '-|', $source) || error("cannot run $source: $!");
		while (my $line = <$sfd>) {
			print ${tfd} $line;
		}
		if (!close($sfd)) {
			error("cannot close handle from $source: $!") if $!;
			error_exitcode($source);
		}
		close($tfd) || error("cannot close $target: $!");
		# Set the mtime (and atime) to ensure reproducibility.
		utime($sstat[9], $sstat[9], $target);
	} else {
		_install_file_to_path($mode, $source, $target);
	}
	return 1;
}

sub restore_file_on_clean {
	my ($file) = @_;
	my $bucket_index = 'debian/.debhelper/bucket/index';
	my $bucket_dir = 'debian/.debhelper/bucket/files';
	my $checksum;
	install_dir($bucket_dir);
	if ($file =~ m{^/}) {
		error("restore_file_on_clean requires a path relative to the package dir");
	}
	$file =~ s{^\./}{}g;
	$file =~ s{//++}{}g;
	if ($file =~ m{^\.} or $file =~ m{/CVS/} or $file =~ m{/\.svn/}) {
		# We do not want to smash a Vcs repository by accident.
		warning("Attempt to store $file, which looks like a VCS file or");
		warning("a hidden package file (like quilt's \".pc\" directory)");
		error("This tool probably contains a bug.");
	}
	if (-l $file or not -f _) {
		error("Cannot store $file: Can only store regular files (no symlinks, etc.)");
	}
	require Digest::SHA;

	$checksum = Digest::SHA->new('256')->addfile($file, 'b')->hexdigest;

	if (not $dh{NO_ACT}) {
		my ($in_index);
		open(my $fd, '+>>', $bucket_index)
			or error("open($bucket_index, a+) failed: $!");
		seek($fd, 0, 0);
		while (my $line = <$fd>) {
			my ($cs, $stored_file);
			chomp($line);
			($cs, $stored_file) = split(m/ /, $line, 2);
			next if ($stored_file ne $file);
			$in_index = 1;
		}
		if (not $in_index) {
			# Copy and then rename so we always have the full copy of
			# the file in the correct place (if any at all).
			doit('cp', '-an', '--reflink=auto', $file, "${bucket_dir}/${checksum}.tmp");
			rename_path("${bucket_dir}/${checksum}.tmp", "${bucket_dir}/${checksum}");
			print {$fd} "${checksum} ${file}\n";
		}
		close($fd) or error("close($bucket_index) failed: $!");
	}

	return 1;
}

sub restore_all_files {
	my $bucket_index = 'debian/.debhelper/bucket/index';
	my $bucket_dir = 'debian/.debhelper/bucket/files';

	return if not -f $bucket_index;
	open(my $fd, '<', $bucket_index)
		or error("open($bucket_index) failed: $!");

	while (my $line = <$fd>) {
		my ($cs, $stored_file, $bucket_file);
		chomp($line);
		($cs, $stored_file) = split(m/ /, $line, 2);
		$bucket_file = "${bucket_dir}/${cs}";
		# Restore by copy and then rename.  This ensures that:
		# 1) If dh_clean is interrupted, we can always do a full restore again
		#    (otherwise, we would be missing some of the files and have to handle
		#     that with scary warnings)
		# 2) The file is always fully restored or in its "pre-restore" state.
		doit('cp', '-an', '--reflink=auto', $bucket_file, "${bucket_file}.tmp");
		rename_path("${bucket_file}.tmp", $stored_file);
	}
	close($fd);
	return;
}

sub open_gz {
	my ($file) = @_;
	my $fd;
	eval {
		require PerlIO::gzip;
	};
	if ($@) {
		open($fd, '-|', 'gzip', '-dc', $file)
		  or die("gzip -dc $file failed: $!");
	} else {
		# Pass ":unix" as well due to https://rt.cpan.org/Public/Bug/Display.html?id=114557
		# Alternatively, we could ensure we always use "POSIX::_exit".  Unfortunately,
		# loading POSIX is insanely slow.
		open($fd, '<:unix:gzip', $file)
		  or die("open $file [<:unix:gzip] failed: $!");
	}
	return $fd;
}

sub deprecated_functionality {
	my ($warning_msg, $compat_removal, $removal_msg) = @_;
	if (defined($compat_removal) and not compat($compat_removal - 1)) {
		my $msg = $removal_msg // $warning_msg;
		warning($msg);
		error("This feature was removed in compat ${compat_removal}.");
	} else {
		warning($warning_msg);
		warning("This feature will be removed in compat ${compat_removal}.")
		  if defined($compat_removal);
	}
	return 1;
}

sub log_installed_files {
	my ($package, @patterns) = @_;

	return if $dh{NO_ACT};

	my $log = generated_file($package, 'installed-by-' . basename($0));
	open(my $fh, '>>', $log) or error("open $log: $!");
	for my $src (@patterns) {
		print $fh "$src\n";
	}
	close($fh) or error("close $log: $!");

	return 1;
}

use constant {
	# The ELF header is at least 0x32 bytes (32bit); any filer shorter than that is not an ELF file
	ELF_MIN_LENGTH => 0x32,
	ELF_MAGIC => "\x7FELF",
	ELF_ENDIAN_LE => 0x01,
	ELF_ENDIAN_BE => 0x02,
	ELF_TYPE_EXECUTABLE => 0x0002,
	ELF_TYPE_SHARED_OBJECT => 0x0003,
};

sub is_so_or_exec_elf_file {
	my ($file) = @_;
	open(my $fd, '<:raw', $file) or error("open $file: $!");
	my $buflen = 0;
	my ($buf, $endian);
	while ($buflen < ELF_MIN_LENGTH) {
		my $r = read($fd, $buf, ELF_MIN_LENGTH - $buflen, $buflen) // error("read ($file): $!");
		last if $r == 0; # EOF
		$buflen += $r
	}
	close($fd);
	return 0 if $buflen < ELF_MIN_LENGTH;

	return 0 if substr($buf, 0x00, 4) ne ELF_MAGIC;
	$endian = unpack('c', substr($buf, 0x05, 1));
	my ($long_format, $short_format);

	if ($endian == ELF_ENDIAN_BE) {
		$long_format = 'N';
		$short_format = 'n';
	} elsif ($endian == ELF_ENDIAN_LE) {
		$long_format = 'V';
		$short_format = 'v';
	} else {
		return 0;
	}
	my $elf_version = substr($buf, 0x14, 4);
	my $elf_type = substr($buf, 0x10, 2);


	return 0 if unpack($long_format, $elf_version) != 0x00000001;
	my $elf_type_unpacked = unpack($short_format, $elf_type);
	return 0 if $elf_type_unpacked != ELF_TYPE_EXECUTABLE and $elf_type_unpacked != ELF_TYPE_SHARED_OBJECT;
	return 1;
}

# Returns true iff the given argument is an empty directory.
# Corner-cases:
#  - false if not a directory
sub is_empty_dir {
	my ($dir) = @_;
	return 0 if not -d $dir;
	my $ret = 1;
	opendir(my $dir_fd, $dir) or error("opendir($dir) failed: $!");
	while (defined(my $entry = readdir($dir_fd))) {
		next if $entry eq '.' or $entry eq '..';
		$ret = 0;
		last;
	}
	closedir($dir_fd);
	return $ret;
}

sub on_pkgs_in_parallel(&) {
	unshift(@_, $dh{DOPACKAGES});
	goto \&on_items_in_parallel;
}

# Given a list of files, find all hardlinked files and return:
# 1: a list of unique files (all files in the list are not hardlinked with any other file in that list)
# 2: a map where the keys are names of hardlinks and the value points to the name selected as the file put in the
#    list of unique files.
#
# This is can be used to relink hard links after modifying one of them.
sub find_hardlinks {
	my (@all_files) = @_;
	my (%seen, %hardlinks, @unique_files);
	for my $file (@all_files) {
		my ($dev, $inode, undef, $nlink)=stat($file);
		if (defined $nlink && $nlink > 1) {
			if (! $seen{"$inode.$dev"}) {
				$seen{"$inode.$dev"}=$file;
				push(@unique_files, $file);
			} else {
				# This is a hardlink.
				$hardlinks{$file}=$seen{"$inode.$dev"};
			}
		} else {
			push(@unique_files, $file);
		}
	}
	return (\@unique_files, \%hardlinks);
}

sub on_items_in_parallel {
	my ($pkgs_ref, $code) = @_;
	my @pkgs = @{$pkgs_ref};
	my %pids;
	my $parallel = $MAX_PROCS;
	my $count_per_proc = int( (scalar(@pkgs) + $parallel - 1)/ $parallel);
	my $exit = 0;
	if ($count_per_proc < 1) {
		$count_per_proc = 1;
		if (@pkgs > 3) {
			# Forking has a considerable overhead, so bulk the number
			# a bit.  We do not do this unconditionally, because we
			# want parallel issues (if any) to appear already with 2
			# packages and two procs (because people are lazy when
			# testing).
			#
			# Same reason for also unconditionally forking with 1 pkg
			# in 1 proc.
			$count_per_proc = 2;
		}
	}
	# Assertion, $count_per_proc * $parallel >= scalar(@pkgs)
	while (@pkgs) {
		my @batch = splice(@pkgs, 0, $count_per_proc);
		my $pid = fork() // error("fork: $!");
		if (not $pid) {
			# Child processes should not write to the log file
			inhibit_log();
			eval {
				$code->(@batch);
			};
			if (my $err = $@) {
				$err =~ s/\n$//;
				print STDERR "$err\n";
				exit(2);
			}
			exit(0);
		}
		$pids{$pid} = 1;
	}
	while (%pids) {
		my $pid = wait;
		error("wait() failed: $!") if $pid == -1;
		delete($pids{$pid});
		if ($? != 0) {
			$exit = 1;
		}
	}
	if ($exit) {
		error("Aborting due to earlier error");
	}
	return;
}

*on_selected_pkgs_in_parallel = \&on_items_in_parallel;

sub compute_doc_main_package {
	my ($doc_package) = @_;
	# if explicitly set, then choose that.
	return $dh{DOC_MAIN_PACKAGE} if $dh{DOC_MAIN_PACKAGE};
	# In compat 10 (and earlier), there is no auto-detection
	return $doc_package if compat(10);
	my $target_package = $doc_package;
	# If it is not a -doc package, then docs should be installed
	# under its own package name.
	return $doc_package if $target_package !~ s/-doc$//;
	# FOO-doc hosts the docs for FOO; seems reasonable
	return $target_package if exists($package_types{$target_package});
	if ($doc_package =~ m/^lib./) {
		# Special case, "libFOO-doc" can host docs for "libFOO-dev"
		my $lib_dev = "${target_package}-dev";
		return $lib_dev if exists($package_types{$lib_dev});
		# Technically, we could go look for a libFOO<something>-dev,
		# but atm. it is presumed to be that much of a corner case
		# that it warrents an override.
	}
	# We do not know; make that clear to the caller
	return;
}

sub dbgsym_tmpdir {
	my ($package) = @_;
	return "debian/.debhelper/${package}/dbgsym-root";
}


{
	my %known_packages;
	sub assert_opt_is_known_package {
		my ($package, $method) = @_;
		%known_packages = map { $_ => 1 } getpackages() if not %known_packages;
		if (not exists($known_packages{$package})) {
			error("Requested unknown package $package via $method, expected one of: " . join(' ', getpackages()));
		}
		return 1;
	}
}

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