#!/usr/bin/env perl

# Last Update: 9 June 2010
# Designed by: Dusan U. Baljevic (dusan.baljevic@ieee.org)
# Coded by:    Dusan U. Baljevic (dusan.baljevic@ieee.org)
#
# Copyright 2010-2015 Dusan Baljevic
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# Define PATH
$ENV{'PATH'} = "/bin:/usr/sbin:/sbin:/usr/bin:/usr/local/bin";

# Define Shell
#
$ENV{'SHELL'} = '/bin/sh' if $ENV{'SHELL'} ne '';
$ENV{'IFS'}   = ''        if $ENV{'IFS'}   ne '';

use strict;

# Local variables
#
my $NFSMNT   = q{};
my @NFSARR   = ();
my %opts     = ();
my $OSNAME   = $^O;
my $NFSCHK   = q{};
my $TIMEOUT  = 20;
my $i        = 0;
my $System   = q{};
my $Hostname = q{};
my $Maj      = q{};
my $Version  = q{};
my $Hardware = q{};
my $VH       = q{};
my $Major    = q{};
my $Minor    = q{};
my $Patch    = q{};

# Do not allow to run as unprivileged user
#
if ( $> != 0 ) {
   print "ERROR: The script should be run with root privileges\n";
   exit(1);
}

# Display usage if "-h" option is used
#
sub Usage {
   print <<MYMSG
   USAGE: myprog [-h] -f <nfs_mount_point>

   -f <nfs_mount_point>  NFS mount point
   -h                    Print help message
MYMSG
     ;
   exit(0);
}

if ( eval "require Getopt::Std" ) {
   import Getopt::Std;

   getopts( 'hf:', \%opts );

   if ( $opts{h} ) {
      &Usage;
   }

   $NFSMNT = $opts{f};
}
else {
   warn "ERROR: Perl module Getopt::Std not found\n";
}

if ( eval "require POSIX" ) {
   import POSIX 'uname';
   import POSIX qw(locale_h);
   use POSIX qw/getpgrp tcgetpgrp/;
   ( $System, $Hostname, $Maj, $Version, $Hardware ) = uname();
   if ( defined $Maj ) {
      ( $Major, $Minor, $Patch ) = split( /\./, $Maj );
   }
}
else {
   warn "WARN: Perl module POSIX not found\n";
}

if ( !"$Hostname" ) {
    $VH = `uname -a 2>&1`;
    ( $System, $Hostname, $Maj, undef, $Hardware, undef ) =
      split( /\s+/, $VH );
    $Version = $Maj;
    ( $Major, $Minor, $Patch ) = split( /\./, $Maj );
}

if ( ! "$NFSMNT" ) {
   &Usage;
}

sub NFSTOUT {
   # Ensure to time out if NFS hung after around $TIMEOUT seconds
   #
   my $NFSMNT2 = shift;
   $SIG{"ALRM"} = sub {die "ERROR: Timed out waiting to df(1) $NFSMNT2\n"};
   alarm $TIMEOUT;
   while (1) {
      $i++;
      $NFSCHK = `df -F nfs $NFSMNT2 2>&1`;
      if ( "$NFSCHK" ) {
         last;
      }
   }

   chomp($NFSCHK);
#  if ( grep(/Warning|no file|error/, "$NFSCHK" )) {
   if ( grep(/^df:/, "$NFSCHK") ) {
      print "FAIL: $NFSMNT2 seemingly not NFS-mounted\n";
   }
   else {
      print "PASS: $NFSMNT2 seemingly NFS-mounted\n";
   }
}

# Ensure to time out if NFS hung after around $TIMEOUT seconds
#
$SIG{"ALRM"} = sub {die "ERROR: Timed out waiting to stat() $NFSMNT\n"};
alarm $TIMEOUT;
while (1) {
   $i++;
   @NFSARR = stat($NFSMNT);
   if ( "@NFSARR" ) {
      last;
   }
}

print "INFO: Operating system $OSNAME\n";

# These are some of entries that $OSNAME holds
#
# dec_osf
# solaris
# hpux
# linux

if ( $NFSARR[0] < 0 ) {
   # Operating system like AIX generates negative sdevs for NFS
   #
   print "PASS: $NFSMNT seemingly NFS-mounted\n";
}
elsif ( "$OSNAME" eq "hpux" ) {
   if ( $NFSARR[$#NFSARR] == 0 ) {
      print "FAIL: $NFSMNT seemingly not NFS-mounted\n";
   }
   else {
      NFSTOUT($NFSMNT);
   }
}
elsif ( "$OSNAME" eq "linux" ) {
   $NFSCHK = `stat -f -L -c %T $NFSMNT`;
   chomp($NFSCHK);
   if ( "$NFSCHK" eq "nfs" ) {
      print "PASS: $NFSMNT seemingly NFS-mounted\n";
   }
   else {
      print "FAIL: $NFSMNT seemingly not NFS-mounted\n";
   }
}
elsif ( "$OSNAME" eq "solaris" ) {
   # This worked on old SunOS 4.x but I need to test it on SunOS 5.x
   #
   if ( "$Major" < 5 ) {
      if ( $NFSARR[0] && 0x8000 ) {
         print "PASS: $NFSMNT seemingly NFS-mounted\n";
      }
      else {
         print "FAIL: $NFSMNT seemingly not NFS-mounted\n";
      }
   }
   else {
#     if ( $NFSARR[1] = 2 ) {
#        print "PASS: $NFSMNT seemingly NFS-mounted\n";
#     }
#     else {
#        print "FAIL: $NFSMNT seemingly not NFS-mounted\n";
#     }

      NFSTOUT($NFSMNT);
   }
}
else {
   NFSTOUT($NFSMNT);
}

exit(0);