#!/usr/bin/perl -w
# ------------- HEADER --------------#
#------------------------------------#
#   Replicacao ZFS Filesystems  1.0  #
#                                    #
# --ChangeLog--                      #
# Author: Leal                       #
# Version: 1.0                       #
# Date: 03/set/2008                  #
#------------------------------------#

# perl's configs
use POSIX;
use Fcntl qw(:DEFAULT :flock);
use Getopt::Std;

# procedures..

sub log_print {
    my($now) = strftime "%Y%m%d-%H%M%S", localtime;
    my($texto) = @_;
    $ERROR = 0;
    print STDERR "${LOG_PROGNAME}[$$] $now: @_\n";
    if (($texto =~ /START - Replica/) || ($texto =~ /END - Replica/)) {
     $ERROR = system "$ECMD \"${LOG_PROGNAME}[$$] $now: @_\" >> /var/log/backup/zfs-replicate.$DATE.log 2>&1";
     if ($ERROR) {
      printf "->could not write to the zfs-replicate log - ERROR code: $ERROR";
     }
    }
}

sub log_die {
    &log_print;
    cleanup();
    die("\n");
    # was: exit 1;
    # die is catchable in an "eval".
}

sub open_log {
    my($logfile) = @_;
    $LOGPIPE = 0;
    if (-t STDOUT) {       # guess interactive shell..
       if (open(LOGPIPE, "| tee -a $logfile") && open(STDOUT, ">&LOGPIPE")) {
           $LOGPIPE = 1;
       }
    }
    unless ($LOGPIPE) {
        open(STDOUT, ">> $logfile")
            or log_die "$MESSAGE_FILE $logfile: $!";
    }
    open(STDERR, ">&STDOUT")
        or log_die "Could not DUP stdout -> stderr: $!";
}

sub lock {
    my($pidfile) = @_;
    sysopen PIDFILE, $pidfile, O_WRONLY | O_CREAT
        or log_die "$MESSAGE_FILE $pidfile: $!";
    flock PIDFILE, LOCK_EX | LOCK_NB
        or log_die "$MESSAGE_LOCK pidfile: $pidfile: $!";
    truncate PIDFILE, 0;
    syswrite PIDFILE, "$$\n";
}

sub usage() {
    printf "We must receive informations...\n";
    # printf "Something like: -M <sourcepool> -R <targetpool> -H <host> -N <secondary>...\n";
    printf "Something like: -M <sourcepool> -R <targetpool> -H <host>...\n";
    die("\n");
}

sub run_command {
    my($command, $args) = @_;
    $ERROR = 0;
    log_print "running: $command $args";
    $ERROR = system "$command $args >> /var/log/backup/zfs-replicate.$DATE.log 2>&1";
    if ($ERROR) {
     log_die "->command execution error: $command $args - ERROR code: $ERROR";
    } else {
      log_print "command executed OK";
    }
}

sub cleanup {
 unlink("$DIR_CONTROL/$LOG_PROGNAME.pid");
 if ($LOGPIPE) {
     close STDOUT;
     close STDERR;
     close LOGPIPE;
 }
}

# some variables..
$REQUIRED_UID  = "0";
$MESSAGE_FILE  = "Could not open file";
$MESSAGE_LOCK  = "Could not aquire exclusive lock";
$MESSAGE_DIR   = "Could not access diretory";
$DIR_LOGS      = "/var/log/backup";
$DIR_CONTROL   = "/var/backup/run";

# commands, and options...
$ECMD          = "/usr/bin/echo";
$RCMD          = "/usr/local/bin/zfs-replicate";
$ROPT1         = "-Fv";
$ZCMD          = "/usr/sbin/zfs";
$ZOPT          = "list -Ht filesystem -o name";

# THE GAME...
# better than nothing...
if ($REQUIRED_UID != $>) { printf "You must be root to run this program.."; die("\n"); }

# Date and time for logging...
$DATE = strftime("%Y%m%d", localtime);

# User interaction...
%options=();
$options = getopts('M:R:H:N:', \%options);
usage() unless ($options{M} && $options{R});
if ($options{H}) {
 $ROPT2         = "-r";
}

# Who we are?
$LOG_PROGNAME = "replica" . "-" . "$options{M}";

# initializing logging...
unless (-d $DIR_LOGS) { printf "$MESSAGE_DIR: \"$DIR_LOGS/\""; die("\n");}
open_log("$DIR_LOGS/$LOG_PROGNAME.$DATE.log");
unless (-d $DIR_CONTROL) { printf "$MESSAGE_DIR: \"$DIR_CONTROL/\""; die("\n");}
lock("$DIR_CONTROL/$LOG_PROGNAME.pid");

log_print "START - Replica - v1.0";
@TEXTO = `$ZCMD $ZOPT`;
foreach $FS (@TEXTO) {
        chomp($FS);
        if ($FS =~ /^$options{M}\//){
         if ($options{H}) {
            run_command ("$RCMD $ROPT1 $ROPT2 $options{H} $FS", "$options{R}");
         } else {
            run_command ("$RCMD $ROPT1 $FS", "$options{R}");
         }
        }
}
log_print "END - Replica - v1.0";

cleanup();
exit 0;