Perl Inotify Script Help

English Programming/Scripting
1

Hi all,

I have a perl script using Inotify2 to watch a directory. I have it almost working the way I want it in that it sends an e-mail notification when a file is modified in the directory. This is an sftp directory for incoming files. When a large file is received, the watch will call a sub routine to perform actions (along with sending an e-mail) that the file is modified. However, since the file is being sent via sftp, it is constantly being modified during the send, causing the user to receive multiple e-mails.

Is there any way to set a timeout after it has noticed that a file is being modified? Is this the way to go, or should I try something else?

2

Can’t you call *sleep *from Perl? (not being a Perl programmer myself).

3

If I use sleep, will it suspend the process? This would not be desired in case any other files are arriving during the nap time ;).

I was thinking of this, but wanted to steer away from this because of my comment above.

4

Yes, it will (see man sleep).

You didn’t mention you did look into sleep allready. I can also not study your script nor your design, so I can not decide if this sleep (of mabe a few seconds) influences things negative. Just wanted to point you to its existance.

5

Hi
Aside from Henk’s comments I’ve used http://kodu.neti.ee/~risto/sec/ in
the past for these sorts of activities.

–
Cheers Malcolm °¿° (Linux Counter #276890)
SUSE Linux Enterprise Desktop 11 (x86_64) Kernel 2.6.27.29-0.1-default
up 2 days 19:54, 2 users, load average: 0.16, 0.29, 0.42
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6

I have posted my script below for any comments:

#!/usr/bin/perl

use Linux::Inotify2;

close STDIN;
close STDOUT;
close STDERR;

sub perform_actions;

$dir_base = “/srv/sftp/sftpuser/incoming/”;
my @directories = qw(dir1 dir2);

#create new object
my $inotify = new Linux::Inotify2 or die “unable to create new inotify obejct: $!”;

foreach my $directory (@directories)
{
#add watchers
#print "Adding watch for " . $dir_base.$directory;
$inotify->watch($dir_base.$directory, IN_CREATE | IN_MODIFY, sub { my $event = shift;

my $name = $event->fullname;

if($event->IN_CREATE)
{
perform_actions($name, $dir_base.$directory, “created”);
}
elsif($event->IN_MODIFY)
{
perform_actions($name, $dir_base.$directory, “modified”);
}

#print "$name was accessed
" if $event->IN_ACCESS;
#print "events for $name have been lost
" if $event->IN_Q_OVERFLOW;

$event->w->cancel;

}) or die “watch creation failed: $!”;
}

1 while $inotify->poll;

sub perform_actions {
my ($name, $dir, $action) = @_;

#DO MULTIPLE ACTIONS HERE. NOT RELEVANT FOR POST

e-mail notification if the size is > 0

my $date = date;
my $cmd = qq(echo “The $name file has been $action on machine” | mailx -s “A new file has been received on $date” user_to_email);
system($cmd) if -s $name;
}
}

7

It seems to me that your SFTP daemon is the appropriate place to trigger the notification action. Are their options to the daemon that would allow for this?

8

I can look into options to the daemon. I am using scponlyc as a shell for the sftp user and I think this automatically calls the sftp-server program as it chroots.

Anybody have experience with this?