#!/usr/bin/perl

# Promise has installed Perl 5.004 which is 12 years old, and I have
# version 5.10 on my development machine.  Imagine my suprise.

$old_perl     = 1;

$chmod_cmd    = "/bin/chmod";
$df_cmd       = "/bin/df";
$ln_cmd       = "/bin/ln";
$mv_cmd       = "/bin/mv";
$mkdir_cmd    = "/bin/mkdir";
$rm_cmd       = "/bin/rm";
$rmdir_cmd    = "/bin/rmdir";

$root_dir     = "/";
$profile      = $root_dir . "etc/profile";
$profile_tmp  = $profile . "tmp";
$terminfo     = "/data/usr/share/terminfo";
$terminfo_env = "export TERMINFO=$terminfo\n";

$bak_dir_name = ".tools.BAK";

@dir_list    = ( "bin", "lib", "etc", "data/usr" );

$action = $ARGV[0];

$app_path = $ENV{'APP_PATH'};

# search installed path
if ( $app_path eq "" ) {
   open(IN, "$df_cmd |");
   while(<IN>){
       if (/(VOLUME\d+)/) {
           if ( -d "/$1/PLUGINAPP/TOOLS" ) {
               $app_path = "/$1/PLUGINAPP/TOOLS";
               last;
           }
       }
   }
   close(IN);
}

if ( $app_path eq "" ) {
   die "Can't find the installation path!";
}

# This code "installs" the contents of directories in the array @dir_list
# from the $app_path to the $root_dir, by directory.  No files are coppied
# from $app_path, only symlinks are created within the $root_dir directories
# to the $app_path directories.  When there is a name collision, i.e., there
# is an element $app_path/ABC/XYZ and $root_dir/ABC/XYZ, then a directory
# named $bak_dir_name is created in $root_dir/ABC, and the original file is
# safely stored there: eg. as $root_dir/ABC/$bak_dir_name/XYZ.  Then the
# symlink is created as normal.
#
# When run with the parameter "stop," the process is reversed, the symlinks
# are removed from $root_dir, any files stored in any $bak_dir_name are
# restored and the $bak_dir_name directories are removed.  The removal of
# symlinks checks to make sure that they still point to the $app_dir; if
# they do not or they are not a symlink, then they are left as is.

if ( $action eq "start") {

#    print "Starting up\n";

    foreach $dir_name ( @dir_list ) {
        # make symbolic links from /$dir_name to our $app_path/$dir_name
        $app_dir = "$app_path/" . $dir_name;

        $dest_dir = $root_dir . $dir_name;

        opendir( DIR_HANDLE, $app_dir );
        @file_list = readdir( DIR_HANDLE );
        closedir( DIR_HANDLE );

        foreach $file_name ( @file_list ) {
#            print "  Working on file $file_name\n";
            $full_pathname = "$app_dir" . "/" . "$file_name";
            $link_pathname = "$dest_dir" . "/" . "$file_name";
            next if (($file_name eq ".") || ($file_name eq "..")) ;
            if (( -f  $link_pathname ) || ( -l  $link_pathname )) {
#                print "  Found existing $link_pathname - ";
                # Check for existing link - eg. we were started 2X
                if ( -l  $link_pathname ) {
                    $temp = readlink $link_pathname;
                    if (( readlink $link_pathname ) =~ m/$app_dir/ ) {
#                        print "  Hey, it's our link!\n";
                        next;
                    }
                }
                # Else, it is not ours, save it into a back up dir
                $back_dir = "$dest_dir" . "/" . $bak_dir_name;
                if (! -d $back_dir ) {    # Create it if need be
                    make_dir( $back_dir, 0755 );
                }
                $back_pathname = $back_dir . "/" . $file_name;
#                print "  Moving it to $back_pathname\n";
                move_file( $link_pathname, $back_pathname);
            }
#            print "  Linking $link_pathname to $full_pathname\n";
            link_file( $full_pathname, $link_pathname );
        }
    }

    # Now we fix the TERMINFO environment variable.  It should have been
    # compiled into ncurses when I built it, but that doesn't seem to be
    # working.
    $missing = 1;
    open PROFILE, "+<$profile";
    while(<PROFILE>) {
        if ( $_ eq $terminfo_env ) {
            $missing = 0;
            last;
        }
    }
    if ( $missing ) {
        print PROFILE $terminfo_env;
    }
    close PROFILE;
    exit 0;
}


elsif ($action eq "stop") {

#    print "Stopping\n";

    # Remove symbolic links from our /$dir_name to $app_path/$dir_name
    foreach $dir_name ( @dir_list ) {
        $app_dir = "$app_path/" . $dir_name;

        $dest_dir = $root_dir . $dir_name;

        opendir( DIR_HANDLE, $app_dir );
        @file_list = readdir( DIR_HANDLE );
        closedir( DIR_HANDLE );

        foreach $file_name ( @file_list ) {
            $link_pathname = "$dest_dir" . "/" . "$file_name";
            if ( -l  $link_pathname ) {
                $full_pathname = readlink $link_pathname;
                if ( $full_pathname =~ m/$app_dir/ ) {
#                    print "  Unlinking $link_pathname to $full_pathname\n";
                    del_file( $link_pathname );
                } else {
#                    print "  Not unlinking $link_pathname\n";
                }
            }
        }
        $back_dir = "$dest_dir" . "/" . $bak_dir_name;
        if ( -d $back_dir ) {
            opendir( DIR_HANDLE, $back_dir );
            @file_list = readdir( DIR_HANDLE );
            closedir( DIR_HANDLE );

            foreach $file_name ( @file_list ) {
                next if (($file_name eq ".") || ($file_name eq "..")) ;
                $back_pathname = "$back_dir" . "/" . "$file_name";
                $link_pathname = "$dest_dir" . "/" . "$file_name";
#                print "  Restoring $back_pathname to $link_pathname\n";
                move_file( $back_pathname, $link_pathname );
            }
            # It had better be empty at this point
            del_dir( $back_dir );
        }
    }

    # Now we unfix the TERMINFO environment variable.
    $missing = 1;
    open IN, "<$profile";
    open OUT, ">$profile_tmp";
    while(<IN>) {
        next if ( $_ eq $terminfo_env );
        print OUT;
    }
    del_file( $profile );
    move_file( $profile_tmp, $profile );
    exit 0;
}


sub move_file {
    my $from_file = $_[0];
    my $to_file = $_[1];

    if ( $old_perl ) {
        system("$mv_cmd $from_file $to_file > /dev/null 2> /dev/null ");
    } else {
        ( link $from_file, $to_file ) || die "Move couldn't hard link $from_file to $to_file\n"; 
        ( unlink $from_file ) || die "Move couldn't unlink $from_file\n";
    }
}


sub make_dir {
    my $dir_name = $_[0];
    my $dir_mode = $_[1];

    if ( $old_perl ) {
        system("$mkdir_cmd $dir_name > /dev/null 2> /dev/null ");
        system("$chmod_cmd $dir_mode $dir_name > /dev/null 2> /dev/null ")
    } else {
        mkdir $back_dir, $dir_mode;
    }
}


sub link_file {
    my $file_name = $_[0];
    my $link_name = $_[1];

    if ( $old_perl ) {
        system("$ln_cmd  -s $file_name $link_name > /dev/null 2> /dev/null ");
    } else {
        (symlink $file_name, $link_name) || die "Couldn't symlink\n";
    }
}

sub del_file {
    my $file_name = $_[0];

    if ( $old_perl ) {
        system("$rm_cmd $file_name > /dev/null 2> /dev/null ");
    } else {
        unlink( $file_name );
    }
}

sub del_dir {
    my $dir_name = $_[0];

    if ( $old_perl ) {
        system("$rmdir_cmd $dir_name > /dev/null 2> /dev/null ");
    } else {
        rmdir( $dir_name );
    }

}