#!/usr/bin/perl

use strict;

my $method = 'cp';              # Change to 'ln' to hard-link the files.
chomp(my $cwd = `/bin/pwd`);

sub newroot() {
	my $file = @_[0];

	if ($file eq "") {
		return;
	}
	my @field = split("/", $file);
	my $filename = pop(@field);
	my $path = join("/", @field);

	system("/bin/mkdir -p .".$path);
	if (-l $file) {
		my $linkto = readlink($file);
		if (substr($linkto, 0, 1) eq "/") {
			$file = $linkto;
		} else {
			$file = $path."/".$linkto;
		}
		if (! -e ".".$file) {
			print $file." -> .".$file."\n";
			system("/bin/".$method." ".$file." .".$file);
		}
		if (! -e ".".$path."/".$filename) {
			print ".".$path."/".$filename." -> .".$path."/".$linkto."\n";
			chdir(".".$path);
			system("/bin/ln -s ".$linkto." ".$filename);
			chdir($cwd);
		}
	} else {
		if (! -e ".".$file) {
			print $file." -> .".$file."\n";
			system("/bin/".$method." ".$file." .".$file);
		}
	}
}

sub need_libs() {
	my $file = @_[0];

	my @ldd = `/usr/bin/ldd $file`;
	for (my $i = 0; $i <= $#ldd; $i++) {
		$ldd[$i] =~ s/^.*=>//;
		$ldd[$i] =~ s/\(.*\n$//;
		$ldd[$i] =~ s/\s*//g;
	}

	return @ldd;
}

sub process() {
	my $file = @_[0];

	&newroot($file);
	my @libs = &need_libs($file);
	for my $lib (@libs) {
		&newroot($lib);
	}
}

sub file_exists() {
	my $file = @_[0];

	if (open(FILE, $file)) {
		close(FILE);

		return 0;
	} else {
		return -1;
	}
}

sub help() {
	my $bin = $_[0];

	printf("Usage: %s <executable>\n\n", $bin);
	print("This script can be used to copy executables to a chroot directory.\n");
	print("Go to a chroot directory and run this script from there. It needs\n");
	print("a full path to an exectable as a parameter.\n\n");

	print("Example: 'newroot /bin/bash' will copy bash and the libraries that\n");
	print("bash needs, including their paths, to the current directory.\n\n");

	print("This script is part of the Hiawatha webserver. See hiawatha(1) for\n");
	print("more information about Hiawatha.\n");
}

sub main() {
	my @argv = @_;

	if ($#argv == 0) {
		printf("%s: missing file argument.\n", $argv[0]);
		print("Try 'newroot -h' for more information.\n");
	} elsif ($argv[1] eq '-h') {
		&help($argv[0]);
	} elsif (substr($argv[1], 0, 1) ne '/') {
		print("Invalid argument.\n");
	} else {
		if (substr($argv[1], 0, 1) eq '/') {
			if (&file_exists($argv[1]) == 0) {
				&process($argv[1]);
			} else {
				print("File not found.\n");
			}
		} else {
			print("Enter the complete path an executable.\n");
		}
	}
}

&main($0, @ARGV);