Perl: Finding MD5 checksum of files recusrsivly in directory

#! /usr/bin/perl -w
use strict;
use Digest::MD5 qw(md5_base64);
use constant SUCESS => 0;        # Code for succesful execution.
use constant ERROR => 1;        # Code for error in execution.
my $exit_status = 0;
my $digest = Digest::MD5->new;

if ($#ARGV < 0) {
    print " Inssuficient number of arguments";
    print "\nUsage : $0 [dir1]..\n";
    exit ERROR;
}

#
# Check provided directories exists.
# If not exists then exit showing error,
# otherwise process the directory.
#
foreach my $dirname (@ARGV) {
    chomp ($dirname);
    $dirname = trimall($dirname);
    if (! -d $dirname) {
    print "$dirname is not directory \n";
    $exit_status = ERROR;
    next;
    } elsif (! -r $dirname) {
    print "$dirname is not readable. \n";
    $exit_status = ERROR;
    next;
    }
    processfiles($dirname);
}
print "\n";
exit $exit_status;

#
# processfiles:
#     Read recursively through the directory.
#     If it is file calculate MD5 check sum of
#     conceptual string from the file's
#     [userid] [groupid] [permission] [inode]
#     and file content. Print the file full path
#     and MD5 check sum against it.
#   
#    parameters:
#        string filename: input file for processing.
#    return type: integer: return sucess/failure code.
#

sub processfiles
{
    use Cwd 'abs_path';
    #my $dirname = $_[0];
    my $dirname = abs_path($_[0]);
    chomp ($dirname);
    opendir(DIRH, $dirname);

    #
    # Read all the files and directories execluding the current
    # '.' and parent directory '..'  
    #
   
    my @files = sort (grep { !/^\.|\.\.}$/ } readdir (DIRH));
    closedir(DIRH);
    my $file;
    foreach $file (@files) {
    my $fullpath = $dirname . "/" . $file;
    print "\n$fullpath";
    if (-d "$fullpath") {
        processfiles("$fullpath");
    } else {
        print "\t" . getmd5checksum ("$fullpath");
    }
    }
    return 0;
}

#
# getmd5checksum:
#     Generate a 64 bit Hex MD5 checksum for file contents
#     and string [userid] [groupid] [permission] [inode]
#   
#    parametrs: string file: file of which MD5 check sum need
#                to calculated.
#    return type: MD5 checksum of the contents of the file
#             with conceptual string
#

sub getmd5checksum
{
    my $file = shift;
    if (! -r $file) {
    return "Not readable";
    } else {
    open (FILE, $file) or return"";
    $digest->reset();
    my $fileInfo =  getfileinfo($file);
    $digest->add($fileInfo);
        $digest->addfile(*FILE);
    close (FILE);
    return $digest->b64digest;
    }
}

#
# getfileinfo:
#    Returns formated string for entered file as
#     [uid] [gid] [mode] [ino]
#   
#    parameters:
#        string filename: filename of which we need to
#                  find the conceptual string.
#    return type: string: return conceptual string in
#                  format [uid] [gid] [permission] [ino]
#

sub getfileinfo
{
    my $file = shift;
    my (undef, $ino, $mode, undef, $uid, $gid) = stat($file);
    my $oct = sprintf("%o", $mode & 07777);
    return $uid . " " . $gid . " " . $oct . " " . $ino;
}

#
# trimall:
#    used to trim leading and trailing white space characters
#    from string.
#    parameters:
#        string str: input string from which spaces needs
#        to be removed.
#    return type : string
#        trimed string.
#

sub trimall
{
    my $arg = shift;
    $arg =~ s/^\s+|\s+$//g;
    return $arg;
}