Since you plan to include CronSleepExample in the kit, I added a help
display and also made it *slightly* less insecure by restricting
filenames for LOAD. Attached.
I intentionally didn't put the password in the help display so people
will have to read the source - thereby encouraging them to read the
warnings.
Enjoy.
#!/usr/bin/perl
# Copyright (c) 2011 Timothe Litt <litt at acm dot org>
#
# May be used on the same terms as Perl.
# Sleep hook demo, showing how it enables a background thread
# to provide a simple command interface to a daemon.
use strict;
use warnings;
use Schedule::Cron;
use Socket ':crlf';
use IO::Socket::INET;
my $port = 65331;
our $password = 'Purfect';
our( $lsock, $rin, $win, $maxfd, %servers );
my $cron = new Schedule::Cron( sub { print 'Loaded entry: ', join('', @_ ), "\n"; }, {
nofork => 1,
loglevel => 0,
log => sub { print $_[1], "\n"; },
sleep => \&idler
} );
$cron->add_entry( "* * * * * *", \&init, 'Init', $cron );
$cron->add_entry( "0 0 1 1 *", sub { print "Happy New Year\n"; }, "NewYear" );
print "Please wait while initialization is scheduled\n";
print help();
$cron->run( { detach => 0 } );
exit;
sub idler {
my( $time ) = @_;
my( $rout, $wout );
my( $nfound, $ttg ) = select( $rout=$rin, $wout=$win, undef, $time );
if( $nfound ) {
if( $nfound == -1 ) {
die "select() error: $!\n"; # This will be an internal error, such as a stale fd.
}
for( my $n = 0; $n <= $maxfd; $n++ ) {
if( vec( $rout, $n, 1 ) ) {
my $s = $servers{$n};
$s->{rsub}->( );
}
}
for( my $n = 0; $n <= $maxfd; $n++ ) {
if( vec( $wout, $n, 1 ) ) {
my $s = $servers{$n};
$s->{wsub}->( );
}
}
}
}
# First task run initializes (usually in daemon, after forking closed open files)
# I suppose this could be a postfork callback, but there isn't one...
sub init {
my( $name, $cron ) = @_;
$cron->delete_entry( 'Init' );
$rin = '';
$win = '';
$lsock = IO::Socket::INET->new(
LocalAddr => "localhost:$port",
Proto => 'tcp',
Type => SOCK_STREAM,
Listen => 5,
ReuseAddr => 1,
Blocking => 0,
),
or die "Unable to open status port $port $!\n";
vec( $rin, ($maxfd = $lsock->fileno()), 1 ) = 1;
$servers{$maxfd} = { rsub=>sub { newConn( $lsock, $cron ); } };
print "Ready, my port is localhost:$port\nTo connect:\n telnet localhost $port\n";
return;
}
sub newConn {
my( $lsock, $cron ) = @_;
my $sock = $lsock->accept();
$sock->blocking(0);
my $cx = {
rbuf => '',
wbuf => 'Password: ',
};
my $fd = $sock->fileno();
$maxfd = $fd if( $maxfd < $fd );
vec( $rin, $fd, 1 ) = 1;
vec( $win, $fd, 1 ) = 1;
$servers{$fd} = { rsub=>sub { serverRd( $sock, $cx, $fd ); },
wsub=>sub { serverWr( $sock, $cx, $fd ); },
cron=>$cron,
};
}
sub serverRd {
my( $sock, $cx, $fd ) = @_;
# Read whatever is available. 1000 is arbitrary, 1 will work (with lots of overhead).
# Huge will prevent any other thread from running.
my $rn= $sock->sysread( $cx ->{rbuf}, 1000, length $cx->{rbuf} );
unless( defined $rn ) {
print "Read error: $!\n";
}
unless( $rn ) { # Connection closed by client
vec( $rin, $fd, 1 ) = 0;
vec( $win, $fd, 1 ) = 0;
$sock->close();
undef $cx;
return;
}
# Assemble reads to form whole lines
# Decode each line as a command.
while( $cx->{rbuf} =~ /$LF/sm ) {
$cx->{rbuf} =~ s/$CR//g;
my( $line, $rest );
($line, $rest) = split( /$LF/, $cx->{rbuf}, 2 );
$rest = '' unless( defined $rest );
$cx->{rbuf} = $rest;
# This is not secure, but one has to do something.
# Demos always get used for more than they should..
# Please do better...like user/account validation
# using the system services.
unless( $cx->{authenticated} ){
if( $line eq $password ) {
$cx->{authenticated} = 1;
$cx->{wbuf} .= "Password accepted$CR$LF";
} else {
$cx->{wbuf} .= "Password refused.$CR${LF}Password: ";
}
next;
}
if( $line =~ /^STAT(?:US)?(?: (\w+))?$/i ) {
$cx->{wbuf} .= status( $cron, ($1 || 'normal') );
} elsif( $line =~ /^ADD\s+(\w+)\s+"(.*?)"\s+(.*)$/i ) {
my( $name, $sched ) = ($1, $2);
$cron->add_entry( $sched, \&announce, $1, $3 );
$cx->{wbuf} .= "Added $name '$sched'$CR$LF";
} elsif( $line =~ /^DEL(?:ETE)?\s+(["\w]+)$/i ) {
my $name = $1;
my $idx = $cron->check_entry( $name );
if( defined $idx ) {
$cron->delete_entry( $idx );
$cx->{wbuf} .= "Deleted $name$CR$LF";
} else {
$cx->{wbuf} .= "$name not found$CR$LF";
}
} elsif( $line =~ /^HELP$/i ) {
$cx->{wbuf} .= help();
} elsif( $line =~ /^LOAD\s([\w\._-]+)$/i ) {
my $cfg = $1; # Danger: File permissions of server are used here.
eval {
$cron->load_crontab( $cfg );
};
my $emsg = $@;
$emsg =~ s/\n/$CR$LF/gms;
$cx->{wbuf} .= $emsg || "Loaded $cfg$CR$LF";
} elsif( $line =~ /^Q(?:uit)?$/i ) {
$cx->{wbuf} .= "Bye$CR$LF";
$cx->{wend} = 1;
} else {
$cx->{wbuf} .= "Unrecognized command: $line$CR$LF";
}
}
serverWr( $sock, $cx, $fd );
}
# Server write process
#
# Output as much as possible from our buffer.
# If more remains, keep select mask active
# If done, clear select mask. If last write, close socket.
sub serverWr {
my( $sock, $cx, $fd ) = @_;
if( length $cx->{wbuf} ) {
my $written = $sock->syswrite( $cx->{wbuf} );
$cx->{wbuf} = substr( $cx->{wbuf}, $written );
}
if( length $cx->{wbuf} ) {
vec( $win, $fd, 1 ) = 1;
return;
} else {
vec( $win, $fd, 1 ) = 0;
if( $cx->{wend} ) {
vec( $rin, $fd, 1 ) = 0;
$sock->close();
return;
}
}
}
sub announce {
my( $id, $msg ) = @_;
print "$id: $msg\n";
return;
}
sub status {
my $cron = shift;
my $level = shift;
my $maxtwid = 0;
my @entries = map { $_->[0] } sort { $a->[1] <=> $b->[1] }
map {
my $time = $_->{time};
$maxtwid = length $time if( $maxtwid < length $time );
[ $_,
$cron->get_next_execution_time( $time ),
]
} $cron->list_entries();
my $msg = "Job queue\n";
foreach my $qe ( @entries ) {
my $job = $cron->check_entry( $qe->{args}->[0] );
next unless( defined $job ); #??
$msg .= sprintf( "Job %-4s %-*s Next: %s - %s",
$job, $maxtwid, $qe->{time},
(scalar localtime( $cron->get_next_execution_time( $qe->{time}, 0 ) )),
$qe->{args}->[0] || '<Unnamed>', # Task name
);
if( $level =~ /^debug$/i ) {
$msg .= '( ';
my @uargs = @{$qe->{args}};
$msg .= join( ', ', @uargs[1..$#uargs] ) . ' )';
}
$msg .= "\n";
}
$msg .= "End of job queue\n";
$msg =~ s/\n/$CR$LF/mgs;
return $msg;
}
use Cwd 'getcwd';
sub help {
my $wd = getcwd();
my $msg = <<"HELP";
CAUTION: Not production code. NOT secure.
Do NOT run from privileged account.
Commands:
status
Shows queue
status debug
With argument lists
add name "schedule" A string to be printed when executed
Adds a new task on specified schedule
delete name
Deletes a task (by name)
help
This message.
load file
Loads a crontab file from $wd
CAUTION, this is with server permissions. If
the server can read /etc/passwd (or anything else),
it will display it in the error messages.
As I said, NOT production...
quit
Exits.
HELP
$msg =~ s/\n/$CRLF/gms;
return $msg;
}
