#!/usr/bin/perl
use strict;
use warnings;
use IO::File;
use IO::Pipe;
use feature 'switch';

my ($filename, $conf);

$filename = '/boot/firmware/sysconf.txt';
exit 0 unless -f $filename;

logger('info', "Reading the system configuration settings from $filename");
$conf = read_conf($filename);

if (my $pass = delete($conf->{root_pw})) {
    my $pipe;
    logger('debug', 'Resetting root password');
    open($pipe, '|-', '/usr/sbin/chpasswd') or die $!;
    $pipe->print("root:$pass");
    close($pipe);
}

if (my $name = delete($conf->{hostname})) {
    my $fh;
    logger('debug', "Setting hostname to '$name'");
    $fh = IO::File->new('/etc/hostname', 'w') or die $!;
    $fh->print($name);
    $fh->close;
    system('hostname', '--file', '/etc/hostname');
}

if (scalar keys %$conf) {
    logger('warn', 'Unprocessed keys left in $filename: ' .
	   join(', ', sort keys %$conf));
}

exit 0;

sub read_conf {
    my ($file, $conf, $fh);
    $file = shift;

    $conf = {};
    $fh = IO::File->new($filename, 'r');
    while (my $line = $fh->getline) {
	my ($key, $value);
	# Allow for comments, and properly ignore them
	$line =~ s/#.+//;
	if ( ($key, $value) = ($line =~ m/^\s*([^=]+)\s*=\s*(.*)\s*$/)) {
	    $key = lc($key);
	    if (exists($conf->{$key})) {
		logger('warn',
		       "Repeated configuration key: $key. " .
		       "Overwriting with new value ($value)");
	    }
	    $conf->{$key} = $value;
	}
    }
    $fh->close;

    return $conf;
}

sub logger {
    my ($prio, $msg) = @_;
    system('/bin/logger', '-p', "daemon.$prio",
	   '-t', 'rpi-set-sysconf', $msg);
}