#!/usr/bin/perl
# SPDX-License-Identifier: CC0-1.0

=head1 NAME

dh_dlopenlibdeps - parse dlopen library dependencies from ELF notes

=cut

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

our $VERSION = DH_BUILTIN_VERSION;

=head1 SYNOPSIS

B<dh_dlopenlibdeps> [S<I<debhelper options>>] [B<-X>I<item>]

=head1 DESCRIPTION

B<dh_dlopenlibdeps> is a debhelper program that is responsible for calculating
dlopen library dependencies for packages.

This program follows the dlopen notes metadata specification as defined at
https://systemd.io/ELF_PACKAGE_METADATA/

=head1 OPTIONS

=over 4

=item B<-X>I<item>, B<--exclude=>I<item>

Exclude files that contain F<item> anywhere in their filename from being
parsed. This will make their dependencies be ignored.
This may be useful in some situations, but use it with caution. This option
may be used more than once to exclude more than one thing.

=back

=cut

init();

on_pkgs_in_parallel {
	my $is_elf_file = sub {
		my ($file) = @_;
		my @file_args = Debian::Debhelper::Dh_Lib::_internal_optional_file_args();
		my $ff = qx_cmd('file', @file_args, '--brief', '-e', 'apptype', '-e', 'ascii',
						'-e', 'encoding', '-e', 'cdf', '-e', 'compress', '-e', 'tar', '--', $file);
		return 1 if $ff =~ m/ELF/;
		return 0;
	};

	foreach my $package (@_) {
		my $tmp = tmpdir($package);
		my $ext = pkgext($package);
		my (@filelist);
		my %required_packages;
		my %recommended_packages;
		my %suggested_packages;

		# Generate a list of ELF binaries in the package, ignoring any we were told to exclude.
		my $find_options='';
		if (defined($dh{EXCLUDE_FIND}) && $dh{EXCLUDE_FIND} ne '') {
			$find_options="! \\( $dh{EXCLUDE_FIND} \\)";
		}
		next if not -d $tmp;
		foreach my $file (split(/\n/, `find $tmp -type f \\( -perm /111 -or -name "*.so*" -or -name "*.cmxs" -or -name "*.node" \\) $find_options -print`)) {
			# Prune directories that contain separated debug symbols.
			# CAVEAT: There are files in /usr/lib/debug that are not detached debug symbols, which should be processed. (see #865982)
			next if $file =~ m!^\Q$tmp\E/usr/lib/debug/(lib|lib64|usr|bin|sbin|opt|dev|emul|\.build-id)/!;
			if ($is_elf_file->($file)) {
				push @filelist, $file;
			}
		}

		if (@filelist) {
			my $required_sonames = '';
			my $recommended_sonames = '';
			my $suggested_sonames = '';

			my $sonames = `dlopen-notes --sonames @filelist`;
			foreach my $line (split(/\n/, $sonames)) {
				my ($soname, $priority) = split(' ', $line, 2);

				if ($priority eq 'required') {
					$required_sonames .= " $soname";
				} elsif ($priority eq 'recommended') {
					$recommended_sonames .= " $soname";
				} elsif ($priority eq 'suggested') {
					$suggested_sonames .= " $soname";
				} else {
					warning("Unknown priority $priority for $soname");
				}
			}

			if ($required_sonames) {
				my $dpkg_query = `dpkg-query --search -- $required_sonames`;
				foreach my $line (split(/\n/, $dpkg_query)) {
					chomp $line;
					if ($line =~ m/^local diversion |^diversion by/) {
						next;
					}
					if ($line =~ m/^([-a-z0-9+]+):/) {
						$required_packages{$1} = 1;
					}
				}
			}

			if ($recommended_sonames) {
				my $dpkg_query = `dpkg-query --search -- $recommended_sonames`;
				foreach my $line (split(/\n/, $dpkg_query)) {
					chomp $line;
					if ($line =~ m/^local diversion |^diversion by/) {
						next;
					}
					if ($line =~ m/^([-a-z0-9+]+):/) {
						$recommended_packages{$1} = 1;
					}
				}
			}

			if ($suggested_sonames) {
				my $dpkg_query = `dpkg-query --search -- $suggested_sonames`;
				foreach my $line (split(/\n/, $dpkg_query)) {
					chomp $line;
					if ($line =~ m/^local diversion |^diversion by/) {
						next;
					}
					if ($line =~ m/^([-a-z0-9+]+):/) {
						$suggested_packages{$1} = 1;
					}
				}
			}
		}

		# Always write the substvars file, even if it's empty, so that the variables are defined and
		# there are no warnings when using them in the control file.
		open(SV, ">>debian/${ext}substvars") || error("open debian/${ext}substvars: $!");
		print SV "dlopen:Depends=" . join(", ", sort keys %required_packages) . "\n";
		print SV "dlopen:Recommends=" . join(", ", sort keys %recommended_packages) . "\n";
		print SV "dlopen:Suggests=" . join(", ", sort keys %suggested_packages) . "\n";
		close(SV);
	}
};

=head1 SEE ALSO

L<debhelper(7)>, L<dh_shlibsdeps(1)>

=head1 AUTHOR

Luca Boccassi <bluca@debian.org>

=cut