Parse::Win32Registry(3p)

NAME
Parse::Win32Registry - Parse Windows Registry Files

SYNOPSIS
    use strict;
    use Parse::Win32Registry qw( :REG_
                                 unpack_windows_time
                                 unpack_unicode_string );

    my $filename = shift or die "Filename?";

    my $registry = Parse::Win32Registry->new($filename)
        or die "'$filename' is not a registry file\n";
    my $root_key = $registry->get_root_key
        or die "Could not get root key of '$filename'\n";

    # The following code works on USER.DAT or NTUSER.DAT files

    my $software_key = $root_key->get_subkey(".DEFAULT\\Software")
                    || $root_key->get_subkey("Software");

    if (defined($software_key)) {
        my @user_key_names = (
          "Microsoft\\Windows\\CurrentVersion\\Explorer\\Shell Folders",
          "Microsoft\\Windows\\CurrentVersion\\Explorer\\RunMRU",
        );

        foreach my $name (@user_key_names) {
            if (my $key = $software_key->get_subkey($name)) {
                print "\n", $key->as_string, "\n";
                foreach my $value ($key->get_list_of_values) {
                    print $value->as_string, "\n";
                }
            }
        }

        # This demonstrates how you can deal with a binary value
        # that contains a Unicode string
        foreach my $ver (qw(8.0 9.0 10.0 11.0)) {
            my $key_name = "Microsoft\\Office\\$ver\\Common\\UserInfo";
            if (my $key = $software_key->get_subkey($key_name)) {
                print "\n", $key->as_string, "\n";
                my @value_names = qw(UserName UserInitials Company);
                foreach my $value_name (@value_names) {
                    if (my $value = $key->get_value($value_name)) {
                        print $value->as_string, "\n";
                        my $data = $value->get_data;
                        my $string = unpack_unicode_string($data);
                        print "$value_name = '$string'\n";
                    }
                }
            }
        }
    }

    # The following code works on SYSTEM.DAT or SOFTWARE files

    my $software_key = $root_key->get_subkey("Software") || $root_key;

    if (defined($software_key)) {
        my @software_key_names = (
            "Microsoft\\Windows\\CurrentVersion",
            "Microsoft\\Windows NT\\CurrentVersion",
        );

        foreach my $name (@software_key_names) {
            if (my $key = $software_key->get_subkey($name)) {
                print "\n", $key->as_string, "\n";
                foreach my $value ($key->get_list_of_values) {
                    print $value->as_string, "\n";
                }
            }
        }

        # This demonstrates how you can deal with a Unix date
        # found in a registry value
        my $key_name = "Microsoft\\Windows NT\\CurrentVersion";
        if (my $curver_key = $software_key->get_subkey($key_name)) {
            print "\n", $curver_key->as_string, "\n";
            if (my $value = $curver_key->get_value("InstallDate")) {
                print $value->as_string, "\n";
                my $time = $value->get_data;
                print "InstallDate = ",
                    scalar gmtime $time, " GMT\n";
                print "InstallDate = ",
                    scalar localtime $time, " Local\n";
            }
        }
    }

    # The following code works on SYSTEM.DAT or SYSTEM files

    my $system_key = $root_key->get_subkey("System") || $root_key;

    my $ccs_name = "CurrentControlSet"; # default for Win95
    if (my $key = $system_key->get_subkey("Select")) {
        my $current_value = $key->get_value("Current");
        $ccs_name = sprintf("ControlSet%03d", $current_value->get_data);
        print "CurrentControlSet = $ccs_name\n";
    }

    my $ccs_key = $system_key->get_subkey($ccs_name);

    if (defined($ccs_key)) {
        my @system_key_names = (
            "Control\\ComputerName\\ComputerName",
            "Control\\TimeZoneInformation",
        );

        foreach my $name (@system_key_names) {
            if (my $key = $ccs_key->get_subkey($name)) {
                print "\n", $key->as_string, "\n";
                foreach my $value ($key->get_list_of_values) {
                    print $value->as_string, "\n";
                }
            }
        }

        # This demonstrates how you can deal with a Windows date
        # found in a registry value
        my $key_name = "Control\\Windows";
        if (my $windows_key = $ccs_key->get_subkey($key_name)) {
            print "\n", $windows_key->as_string, "\n";
            if (my $value = $windows_key->get_value("ShutdownTime")) {
                print $value->as_string, "\n";
                my $data = $value->get_data;
                my $time = unpack_windows_time($data);
                print "ShutdownTime = ",
                    scalar gmtime $time, " GMT\n";
                print "ShutdownTime = ",
                    scalar localtime $time, " Local\n";
            }
        }
    }

DESCRIPTION
Parse::Win32Registry is a module for parsing Windows Registry files, allowing you to read the keys and values of a registry file without going through the Windows API.

It provides an object-oriented interface to the keys and values in a registry file. Registry files are structured as trees of keys, with each key containing further subkeys or values.

The module is intended to be cross-platform, and run on those platforms where Perl will run.

It supports both Windows NT registry files (Windows NT, 2000, XP, 2003, Vista, 7) and Windows 95 registry files (Windows 95, 98, Millennium Edition).

It is intended to be used to parse offline registry files. If a registry file is currently in use, you will not be able to open it. However, you can save part or all of a currently loaded registry file using the Windows reg command if you have the appropriate administrative access.

DEPENDENCIES
Requires Perl 5.8.1. All required modules are standard modules.

METHODS
Start by creating a Registry object from a valid registry file. Use the Registry object's get_root_key method to obtain the root key of that registry file. This root key is your first Key object. From this key, you can explore the Key and Value objects that comprise the registry file using the methods described below.

Data is read directly from a registry file when a Key or Value object is created, and discarded when the Key or Value object is destroyed. This avoids any delay in parsing an entire registry file to obtain a Key or Value object as most code only looks at a subset of the keys and values contained in a registry file.

  Registry Object Methods

$registry = Parse::Win32Registry->new( 'filename' )
    Creates a new Registry object for the specified registry file.

$registry->get_root_key
    Returns the root Key object of the registry file.

    The root key of a registry file is not the same as one of the virtual roots of the registry (HKEY_LOCAL_MACHINE, HKEY_USERS, etc) that you might be familiar with from using tools such as REGEDIT.

    The names of root keys vary by operating system and by file. For example, the name of the root key of a Windows XP NTUSER.DAT file is '$$$PROTO.HIV' and the name of the root key of a Windows 98 USER.DAT file is an empty string.

$registry->get_virtual_root_key
$registry->get_virtual_root_key( 'virtual root key name' )
    Returns the virtual root Key object of the registry file.

    In all respects this is exactly the same as the root Key object, except that it pretends to be a virtual root by simply faking its name. It guesses the virtual root key name by looking at the filename of the registry file. For example, if the filename contains 'SYSTEM' the virtual root key will be named 'HKEY_LOCAL_MACHINE\\SYSTEM'. If the guess fails (because the filename is not recognised) the virtual root key will be named 'HKEY_UNKNOWN'.

    You can override the guess by supplying your own root key name. You can use this to pass in your preferred root key name. For example, you could pass the filename of the registry file in as the virtual root key name, which would then cause the filename to appear as part of each key's path.

$registry->get_timestamp
    Returns the embedded timestamp for the registry file as a time value (the number of seconds since your computer's epoch) suitable for passing to gmtime or localtime.

    Only Windows NT registry files have an embedded timestamp.

    Returns nothing if the date is out of range or if called on a Windows 95 registry file.

$registry->get_timestamp_as_string
    Returns the timestamp as a ISO 8601 string, for example, '2010-05-30T13:57:11Z'. The Z indicates that the time is GMT ('Zero Meridian').

    Returns the string '(undefined)' if the date is out of range or if called on a Windows 95 registry file.

$registry->get_embedded_filename
    Returns the embedded filename for the registry file.

    Only Windows NT registry files have an embedded filename.

    Returns nothing if called on a Windows 95 registry file.

$registry->get_filename
    Returns the filename of the registry file.

$registry->get_length
    Returns the length of the registry file.

  Key Object Methods

$key->get_name
    Returns the name of the key. The root key of a Windows 95 based registry file does not have a name; this is returned as an empty string.

$key->get_path
    Returns the path to the key. This shows the all of the keys from the root key to the current key, joined by the path separator '\'.

$key->get_subkey( 'key name' )
    Returns a Key object for the specified subkey name. If a key with that name does not exist, nothing will be returned.

    You can specify a path to a subkey by separating keys using the path separator '\'. Remember to quote any '\' characters with a preceding '\'. For example:

        $key->get_subkey('Software\\Microsoft\\Windows')

    A path is always relative to the current key. It should start with the name of the first subkey in the path, not the current key. If any key in the path does not exist, nothing will be returned.

$key->get_value( 'value name' )
    Returns a Value object for the specified value name. If a value with that name does not exist, nothing will be returned.

    The default value (displayed as '(Default)' by REGEDIT) does not actually have a name. It can obtained by supplying an empty string, e.g. $key->get_value('');

$key->get_value_data( 'value name' )
    Returns the data for the specified value name. If either the value or the value's data does not exist, nothing will be returned.

    This is simply a shortcut for accessing the data of a value without creating an intermediate Value object.

    The following code:

        my $value = $key->get_value('value name');
        if (defined $value) {
            my $data = $value->get_data;
            if (defined $data) {
                ...process data...
            }
        }

    can be replaced with:

        my $data = $key->get_value_data('value name');
        if (defined $data) {
            ...process data...
        }

$key->get_list_of_subkeys
    Returns a list of Key objects representing the subkeys of the current key. If a key has no subkeys, an empty list will be returned.

$key->get_list_of_values
    Returns a list of Value objects representing the values of the current key. If a key has no values, an empty list will be returned.

$key->get_timestamp
    Returns the timestamp for the key as a time value (the number of seconds since your computer's epoch) suitable for passing to gmtime or localtime.

    Only Windows NT registry keys have a timestamp.

    Returns nothing if the date is out of range or if called on a Windows 95 registry key.

$key->get_timestamp_as_string
    Returns the timestamp as an ISO 8601 string, for example, '2010-05-30T13:57:11Z'. The Z indicates that the time is GMT ('Zero Meridian').

    Returns the string '(undefined)' if the date is out of range or if called on a Windows 95 registry key.

$key->as_string
    Returns the path of the key as a string. The timestamp will be appended for Windows NT registry keys.

$key->as_regedit_export
    Returns the path of the key as a string in the Windows Registry Editor Version 5.00 export format. The string will be terminated with a newline character.

    If used in conjunction with the get_virtual_root_key method of Registry objects this should generate key paths interoperable with those exported by REGEDIT.

$key->get_parent
    Returns a Key object for parent of the current key. If the key does not have a valid parent key (which will normally only occur for the root key) nothing will be returned.

$key->is_root
    Returns true if this key is the root key.

$key->get_class_name
    Returns a string containing the class name associated with a key. Only a very few Windows NT registry key have class names.

    Returns nothing if the key has no class name or if called on a Windows 95 registry key.

$key->get_security
    Returns a Security object containing the security information for the key. Only Windows NT registry keys have security information.

    Returns nothing if called on a Windows 95 registry key.

$key->get_subkey_iterator
    Returns an iterator for retrieving the subkeys of the current key. Each time the get_next method of the iterator is used, it will return a single Key object. Keys will be returned one by one until the end of the list is reached, when nothing will be returned.

    It can be used as follows:

        my $subkey_iter = $key->get_subkey_iterator;
        while (my $subkey = $subkey_iter->get_next) {
            # do something with $subkey
            ...
        }

    Note that it is usually simpler to just use $key->get_list_of_subkeys. An iterator might be useful when you need to control the amount of processing you are performing, such as programs that need to remain responsive to user actions.

$key->get_value_iterator
    Returns an iterator for retrieving the values of the current key. Each time the get_next method of the iterator is used, it will return a single Value object. Values will be returned one by one until the end of the list is reached, when nothing will be returned.

    It can be used as follows:

        my $value_iter = $key->get_value_iterator;
        while (my $value = $value_iter->get_next) {
            # do something with $value
            ...
        }

    Note that it is usually simpler to just use $key->get_list_of_values.

$key->get_subtree_iterator
    Returns an iterator for retrieving the entire subtree of keys and values beginning at the current key. Each time the get_next method of the iterator is used, it will return either a Key object or a Key object and a Value object. Each value accompanies the key that it belongs to. Keys or Key/Value pairs will be returned one by one until the end of the list is reached, when nothing will be returned.

    It can be used as follows:

        my $subtree_iter = $key->get_subtree_iterator;
        while (my ($key, $value) = $subtree_iter->get_next) {
            if (defined $value) {
                # do something with $key and $value
                ...
            }
            else {
                # do something with $key
                ...
            }
        }

    Keys and values will be returned in the following order:

        root_key
        root_key\key1
        root_key\key1, value1
        root_key\key1, value2
        root_key\key1\key2
        root_key\key1\key2, value3
        root_key\key1\key2, value4

    If the iterator is used in a scalar context, only Key objects will returned.

        my $subtree_iter = $key->get_subtree_iterator;
        while (my $key = $subtree_iter->get_next) {
            # do something with $key
            ...
        }

    Keys will be returned in the following order:

        root_key
        root_key\key1
        root_key\key1\key2

    Note that it might be simpler to write a recursive function to process the keys and values.

        sub traverse {
            my $key = shift;

            # do something with $key
            ...

            foreach my $value ($key->get_list_of_values) {
                # do something with $value
                ...
            }

            foreach my $subkey ($key->get_list_of_subkeys) {
                # recursively process $key
                traverse($subkey);
            }
        }

        traverse($root_key);

$key->walk( \&callback );
    Performs a recursive descent of all the keys in the subtree starting with the calling key, and calls the callback function for each key reached.

    The callback function will be passed the current key.

        $key->walk( sub {
            my $key = shift;
            print $key->as_string, "\n";
        } );

        $key->walk( sub {
            my $key = shift;
            print $key->as_regedit_export;
            foreach my $value ($key->get_list_of_values) {
                print $value->as_regedit_export;
            }
        } );

  Value Object Methods

$value->get_name
    Returns the name of the value. In both Windows NT and Windows 95 based registry files you can get values without a name. This is returned as an empty string.

$value->get_type
    Returns the integer representing the type of the value (where 1 is a REG_SZ, 2 is a REG_EXPAND_SZ, etc). The constants for the value types can be imported from the Parse::Win32Registry module with

        use Parse::Win32Registry qw( :REG_ );

$value->get_type_as_string
    Returns the type of the value as a string instead of an integer constant, making it more suitable for printed output.

$value->get_data
    Returns the data for the value.

    REG_SZ and REG_EXPAND_SZ values will be returned as strings. String data will be converted from Unicode (UCS-2LE) for Windows NT based registry files. Any terminating null characters will be removed.

    REG_MULTI_SZ values will be returned as a list of strings when called in a list context, and as a string with each element separated by the list separator $" when called in a scalar context. (The list separator defaults to the space character. See perlvar for further information.) String data will be converted from Unicode (UCS-2LE) for Windows NT based registry files.

        # get REG_MULTI_SZ data as a string
        my $data = $multi_sz_value->get_data;

        # get REG_MULTI_SZ data as a list
        my @data = $multi_sz_value->get_data;

    REG_DWORD values are unpacked and returned as unsigned integers.

    All other types are returned as packed binary strings. To extract data from these packed binary strings, you will need to use Perl's unpack function, or one of the provided support functions.

    Nothing will be returned if the data is invalid.

$value->get_data_as_string
    Returns the data for a value, making binary data safe for printed output.

    REG_SZ and REG_EXPAND_SZ values will be returned directly from get_data, REG_MULTI_SZ values will have their component strings prefixed by indices to more clearly show the number of elements, and REG_DWORD values will be returned as a hexadecimal number followed by its parenthesized decimal equivalent. All other types of values will be returned as a string of hex octets.

    '(invalid data)' will be returned if the data is invalid (i.e. when get_data returns undef).

    '(no data)' will be returned if get_data returns an empty string.

$value->get_raw_data
    Returns the data for a value exactly as it was read from the registry, without the processing normally performed by get_data.

    It is intended for those rare occasions when you need to access binary data that has been inappropriately stored in a REG_SZ, REG_EXPAND_SZ, REG_MULTI_SZ, or REG_DWORD value.

$value->as_string
    Returns the name, type, and data for the value as a string, safe for printed output.

    '(Default)' will be used for the names of those values that do not have names.

$value->as_regedit_export
    Returns the name, type, and data for the value as a string, in the Windows Registry Editor Version 5.00 export format. The string will contain line breaks to ensure that no line is longer than 80 characters. Each line will be terminated with a newline character.

    '@' will be used for the names of those values that do not have names.

    This should generate values interoperable with those exported by REGEDIT.

  Security Object Methods
Only Windows NT registry files contain security information to control access to the registry keys. This information is stored in security entries which are distributed through the registry file separately from the keys that they apply to. This allows the registry to share security information amongst a large number of keys whilst unnecessary duplication.

Security entries link to other security entries in a circular chain, each entry linking to the one that precedes it and the one that follows it.

$security->get_security_descriptor
    Returns a Security Descriptor Object representing the security descriptor contained in the security information registry entry.

$security->get_next
    Returns the next security object.

$security->get_previous
    Returns the previous security object.

$security->get_reference_count
    Returns the reference count for the security object.

  Security Descriptor Object Methods
A Security Descriptor object represents a security descriptor which contains an owner SID, a primary group SID, a System ACL, and a Discretionary ACL.

$security_descriptor->get_owner
    Returns a SID Object containing the Owner SID.

$security_descriptor->get_group
    Returns a SID Object containing the primary group SID.

$security_descriptor->get_sacl
    Returns an ACL Object containing the System ACL. The System ACL contains those ACEs used for auditing. Nothing will be returned if the security descriptor does not contain a System ACL.

$security_descriptor->get_dacl
    Returns an ACL Object containing the Discretionary ACL. The Discretionary ACL contains those ACEs used for access control. Nothing will be returned if the security descriptor does not contain a Discretionary ACL.

$security_descriptor->as_stanza
    Returns a multi-line string containing the security descriptor formatted for presentation. It will contain a line for the owner SID, the group SID, and each component ACE of the System ACL and the Discretionary ACL. Each line will be terminated by a newline character.

  ACL Object Methods
An ACL object represents an Access Control List, which comprises a list of Access Control Entries.

$acl->get_list_of_aces
    Returns a list of ACE Objects representing the ACEs in the order they appear in the ACL. If the ACL contains no ACEs, nothing will be returned.

$acl->as_stanza
    Returns a multi-line string containing the ACL formatted for presentation. It will contain a line for each component ACE of the ACL. Each line will be terminated by a newline character.

  ACE Object Methods
An ACE object represents an Access Control Entry. An ACE describes the permissions assigned (the access mask) to a Security Identifier (the trustee).

$ace->get_type
    Returns an integer containing the ACE type, where 0 indicates an ACCESS_ALLOWED ACE, 1 an ACCESS_DENIED ACE, and 2 a SYSTEM_AUDIT ACE. Typically you will encounter ACCESS_ALLOWED and ACCESS_DENIED ACEs in Discretionary ACLs and SYSTEM_AUDIT ACEs in System ACLs.

$ace->get_type_as_string
    Returns the type as a string, rather than integer.

$ace->get_flags
    Returns an integer containing the ACE flags.

$ace->get_access_mask
    Returns an integer containing the ACE access mask. The access mask controls what actions the trustee might perform with the object the ACE applies to.

$ace->get_trustee
    Returns a SID Object containing the trustee that this ACE is associated with.

$ace->as_string
    Returns a string containing the ACE formatted for presentation.

  SID Object Methods
A SID object represents a Security Identifier.

$sid->get_name
    Returns a string containing a name for the SID (e.g. "Administrators" for S-1-5-32-544) if it is a "well known" SID. See Microsoft Knowledge Base Article KB243330.

$sid->as_string
    Returns a string containing the SID formatted for presentation.

EXPORTS

  Constants
On request, Parse::Win32Registry will export the registry type constants:

    use Parse::Win32Registry qw( :REG_ );

The :REG_ tag exports all of the following constants:

    REG_NONE
    REG_SZ
    REG_EXPAND_SZ
    REG_BINARY
    REG_DWORD
    REG_DWORD_BIG_ENDIAN
    REG_LINK
    REG_MULTI_SZ
    REG_RESOURCE_LIST
    REG_FULL_RESOURCE_DESCRIPTOR
    REG_RESOURCE_REQUIREMENTS_LIST
    REG_QWORD

You can import individual types by specifying them, for example:

    use Parse::Win32Registry qw( REG_SZ REG_DWORD );

SUPPORT FUNCTIONS
Parse::Win32Registry provides a number of support functions, which are exported on request. All of the support functions can be imported with:

    use Parse::Win32Registry qw( :functions );

  Unpacking Binary Data
There are a number of functions for assisting in unpacking binary data found in registry values. These functions are exported on request:

    use Parse::Win32Registry qw( unpack_windows_time
                                 unpack_unicode_string
                                 unpack_sid
                                 unpack_ace
                                 unpack_acl
                                 unpack_security_descriptor );

These unpack functions also return the length of the packed object when called in a list context.

For example, to extract one SID:

    my $sid = unpack_sid($data);

To extract a series of SIDs:

    my $pos = 0;
    while ($pos < length($data)) {
        my ($sid, $packed_len) = unpack_sid(substr($data, $pos));
        last if !defined $sid; # abort if SID not defined

        # ...do something with $sid...

        $pos += $packed_len; # move past the packed SID
    }

$time = unpack_windows_time( $data ) =item ( $time, $packed_len ) = unpack_windows_time( $data )
    Returns the epoch time for the Win32 FILETIME contained in the supplied binary data. A Win32 FILETIME is a 64-bit integer containing the number of 100-nanosecond intervals since January 1st, 1601 and can sometimes be found in Windows NT registry values.

    Returns nothing if the date is earlier than your computer's epoch. The epoch begins at January 1st, 1970 on Unix and Windows machines.

    When called in a list context, it will also return the space used in the supplied data by the windows time.

    (This function can also be called by its previous name of convert_filetime_to_epoch_time.)

$str = unpack_unicode_string( $data ) =item ( $str, $packed_len ) = unpack_unicode_string( $data )
    Extracts a Unicode (UCS-2LE) string from the supplied binary data. Any terminating null characters are dropped. Unicode (UCS-2LE) strings are sometimes encountered in Windows NT registry REG_BINARY values.

    Note that Unicode strings contained in REG_SZ, REG_EXPAND_SZ, and REG_MULTI_SZ values are already automatically decoded by the get_data method of a Value object.

    When called in a list context, it will also return the space used in the supplied data by the Unicode string.

$sid = unpack_sid( $data ) =item ( $sid, $packed_len) = unpack_sid( $data )
    Returns a SID Object representing the SID contained in the supplied data. Returns nothing if the supplied data does not appear to contain a valid SID.

    When called in a list context, it will also return the space used in the supplied data by the SID.

$ace = unpack_ace( $data ) =item ( $ace, $packed_len ) = unpack_ace( $data )
    Returns an ACE Object representing the ACE contained in the supplied data. Returns nothing if the supplied data does not appear to contain a valid ACE.

    When called in a list context, it will also return the space used in the supplied data by the ACE.

$acl = unpack_acl( $data ) =item ( $acl, $packed_len ) = unpack_acl( $data )
    Returns an ACL Object representing the ACL contained in the supplied data. Returns nothing if the supplied data does not appear to contain a valid ACL.

    When called in a list context, it will also return the space used in the supplied data by the ACL.

$sd = unpack_security_descriptor( $data ) =item ( $sd, $packed_len ) = unpack_security_descriptor( $data )
    Returns a Security Descriptor Object representing the security descriptor contained in the supplied data. Returns nothing if the supplied data does not appear to contain a valid security descriptor.

    When called in a list context, it will also return the space used in the supplied data by the security descriptor.

  Formatting Data
These functions are exported on request:

    use Parse::Win32Registry qw( iso8601 hexdump );

$str = iso8601( $epoch_time )
    Returns the ISO8601 string for the supplied $epoch_time, for example, '2010-05-30T13:57:11Z'. It assumes the supplied $epoch_time is in UTC, and appends 'Z' to indicate this.

    The string '(undefined)' will be returned if the epoch time is out of range.

        my $data = $reg_binary_value->get_data;

        # extract the Win32 FILETIME starting at the 9th byte of $data
        my $time = unpack_windows_time( substr( $data, 8 ) );
        my $time_as_string = iso8601( $time );
        print "$time_as_string\n";

    There are a number of ways of displaying a timestamp. For example:

        use Parse::Win32Registry qw(iso8601);
        use POSIX qw(strftime);
        print iso8601($key->get_timestamp);
        print scalar(gmtime($key->get_timestamp)), " GMT\n";
        print scalar(localtime($key->get_timestamp)), " Local\n";
        print strftime("%Y-%m-%d %H:%M:%S GMT",
                       gmtime($key->get_timestamp)), "\n";
        print strftime("%Y-%m-%d %H:%M:%S Local",
                       localtime($key->get_timestamp)), "\n";

    ...might produce the following output:

        2000-08-06T23:42:36Z
        Sun Aug  6 23:42:36 2000 GMT
        Mon Aug  7 07:42:36 2000 Local
        2000-08-06 23:42:36 GMT
        2000-08-07 07:42:36 Local

$str = hexdump( $data )
    Returns a multi-line string containing a hexadecimal dump of the supplied data. Each line will display 16 bytes in hexadecimal and ASCII, and will be terminated by a newline character.

  Processing Multiple Registry Files Simultaneously
There are three support functions that create iterators for simultaneously processing the keys and values of multiple registry files. These functions are exported on request:

    use Parse::Win32Registry qw( make_multiple_subkey_iterator
                                 make_multiple_value_iterator
                                 make_multiple_subtree_iterator );

Handling lists of subkeys or values should be done with a little care as some of the processed registry files might not contain the subkey or value being examined and the list will contain missing entries:

    ($key1, $key2, undef, $key4)

One way of handling this is to use map to check that a key is defined and return undef if the subkey or value is not present.

    @subkeys = map { defined $_ && $_->get_subkey('subkey') || undef } @keys;

    @values = map { defined $_ && $_->get_value('value') || undef } @keys;

$iter = make_multiple_subkey_iterator( $key1, $key2, $key3, ... )
    Returns an iterator for retrieving the subkeys of the supplied Key objects. Each call to the get_next method of the iterator returns a reference to a list of Key objects with the same name and path. If any of the supplied Key objects does not have a subkey with that name, then that subkey will be undefined.

        my $subkey_iter = make_multiple_subkey_iterator($key1, $key2, ...);
        while (my ($subkey1, $subkey2, ...) = $subkey_iter->get_next) {
            ...
        }

        my $subkey_iter = make_multiple_subkey_iterator($key1, $key2, ...);
        while (my @subkeys = $subkey_iter->get_next) {
            foreach my $subkey (@subkeys) {
                if (defined $subkey) {
                    ...
                }
            }
        }

$iter = make_multiple_value_iterator( $key1, $key2, $key3, ... )
    Returns an iterator for retrieving the values of the supplied Key objects. Each call to the get_next method of the iterator returns a reference to a list of Value objects with the same name. If any of the supplied Key objects does not have a value with that name, then that value will be undefined.

        my $value_iter = make_multiple_value_iterator($key1, $key2, ...);
        while (my ($value1, $value2, ...) = $value_iter->get_next) {
            ...
        }

$iter = make_multiple_subtree_iterator( $key1, $key2, $key3, ... )
    Returns an iterator for retrieving the immediate subkeys and all descendant subkeys of the supplied Key objects. Each call to the get_next method of the iterator returns a list of Key objects with the same name and path. If any of the supplied Key objects does not have a subkey with that name, then that subkey will be undefined.

    Each call to the get_next method of the iterator returns it will return either a reference to a list of Key objects or a reference to a list of Key objects and a reference to a list of a Value objects, with each list of values accompanying the list of keys that they belong to. Nothing is returned when the end of the list is reached.

        my $subtree_iter = make_multiple_subtree_iterator($key1, $key2, ...);
        while (my $subkeys_ref = $tree_iter->get_next) {
            # do something with @$subkeys_ref
        }

        my $subtree_iter = make_multiple_subtree_iterator($key1, $key2, ...);
        while (my ($subkeys_ref, $values_ref) = $tree_iter->get_next) {
            if (defined $values_ref) {
                # do something with @$subkeys_ref and @$values_ref
                for (my $i = 0; $i < @$values_ref; $i++) {
                    print $values_ref->[$i]->as_string, "\n";
                }
                ...
            }
            else {
                # do something with @$subkeys_ref
                my $first_defined_subkey = (grep { defined } @$subkeys_ref)[0];
                print $first_defined_subkey->as_string, "\n";
                ...
            }
        }

  Comparing Keys and Values
These functions are exported on request:

    use Parse::Win32Registry qw( compare_multiple_keys
                                 compare_multiple_values );

@changes = compare_multiple_keys( $key1, $key2, ... );
    Returns a list of strings describing the differences found between the supplied keys. The keys are compared in the order they are supplied. If one of the supplied keys is undefined, it is assumed to have been deleted.

    The possible changes are 'ADDED', and 'DELETED', and for Windows NT registry keys (which have timestamps) 'NEWER', and 'OLDER'.

    For example, compare_multiple_keys($k1, $k2, $k3) would return the list ('', 'NEWER', '') if $k2 had a more recent timestamp than $k1, but $k3 had the same timestamp as $k2.

    You can count the number of changed keys using the grep operator:

        my $num_changes = grep { $_ } @changes;

@changes = compare_multiple_values( $value1, $value2, ... );
    Returns a list of strings describing the differences found between the supplied values. The values are compared in the order they are supplied. If one of the supplied values is undefined, it is assumed to have been deleted.

    The possible changes are 'ADDED', 'DELETED', and 'CHANGED'.

    For example, compare_multiple_keys($v1, $v2, $v3) would return the list ('', 'ADDED', 'CHANGED') if $v2 exists but $v1 did not, and $v3 had different data from $v2.

    You can count the number of changed values using the grep operator:

        my $num_changes = grep { $_ } @changes;

HANDLING INVALID DATA
The Parse::Win32Registry module will skip keys or values that cannot be successfully parsed.

If keys or values cannot be parsed, then the get_subkey and get_value methods of Key objects will return nothing.

The get_list_of_subkeys and get_list_of_values methods of Key objects will skip those keys or values that cannot be parsed. If none of the keys or values can be parsed successfully, an empty list will be returned.

Additionally, values (in Windows NT registry files) often store data in a separate area of the registry file. If the value can be parsed, but the data cannot, a Value object will be created, but it will have no data. The get_data method will return nothing.

The most robust way of handling keys or values or data is therefore to check that they are defined before processing them. For example:

    my $key = $root_key->get_subkey( "Software\\Perl" );
    if ( defined $key ) {
        print $key->as_string, "\n";
        my $value = $key->get_value( "Version" );
        if ( defined $value ) {
            print $value->as_string, "\n";
            my $data = $value->get_data;
            if ( defined $data ) {
                # process $data in some way...
            }
        }
    }

You might not feel this robustness is necessary for your scripts.

You can be alerted when there are problems parsing registry keys or values by switching on warnings with:

    Parse::Win32Registry->enable_warnings;

They can be switched off again with:

    Parse::Win32Registry->disable_warnings;

LOW-LEVEL METHODS
These methods are intended for those who want to look at the structure of a registry file, but with something a little more helpful than a hex editor. They are not designed for pulling data out of keys and values: they are designed to make it easier to look at the underlying components of a registry file.

Windows NT registry files are composed of one or more Hbin blocks. Hbin blocks can contain a series of entries, such as key, value, and security entries, but also includes subkey lists, value lists, key class names, and value data.

Windows 95 registry files are composed of an RGKN block, followed by one or more RGDB blocks. RGKN blocks contain the entries which link the registry keys in the form of a tree. RGDB blocks contain a corresponding entry for each key in the RGKN block. This RGDB entry includes the name of the key and any associated values. For convenience, when iterating the entries in an RGDB block, each will be returned as a key entry followed by zero or more value entries.

To see demonstrations of how these methods can be used, look at the regscan.pl, gtkregscope.pl, and wxregscope.pl scripts.

  Registry Object Methods

$registry->get_block_iterator
    Returns an iterator for retrieving all the blocks in a registry file. Each time the get_next method of the iterator is used, it will return a single Block object. Blocks will be returned one by one until the end of the registry file is reached, when nothing will be returned.

    Typically you would iterate over all the blocks in a registry file, and iterate over all the entries in each block:

        my $block_iter = $registry->get_block_iterator;
        while (my $block = $block_iter->get_next) {
            my $entry_iter = $block->get_entry_iterator;
            while (my $entry = $entry_iter->get_next) {
                ...
            }
        }

$registry->get_entry_iterator
    Returns an iterator for retrieving all the entries in a registry file. Each time the get_next method of the iterator is used, it will return a single Entry object. Entries will be returned one by one until the end of the registry file is reached, when nothing will be returned.

    This is simply a more convenient method for retrieving all the entries in a registry file, which does not require you to iterate over each block.

  Block Object Methods

$block->get_entry_iterator
    Returns an iterator for retrieving all the entries in a block. Each time the get_next method of the iterator is used, it will return a single Entry object. Entries will be returned one by one until the end of the block is reached, when nothing will be returned.

        my $entry_iter = $block->get_entry_iterator;
        while (my $entry = $entry_iter->get_next) {
            ...
        }

$block->get_offset
    Returns the position of the block relative to the start of the file.

$block->get_length
    Returns the length of the block.

$block->parse_info
    Returns a string containing a summary of the parser information for the block.

$block->unparsed
    Returns a string containing a hex dump of the unparsed on-disk data for the block header.

$block->get_raw_bytes
    Returns the unparsed on-disk data for the block header.

  Entry Object Methods
In addition to the basic methods provided by all entries, if an entry is a key, value, or security entry, it will also provide the methods available to Key, Value, or Security objects. You might therefore find it useful to check what methods are available so that you can use them:

    # use Entry object methods...
    ...
    if ($entry->can('get_subkey')) {
        # use Key object methods...
    }
    elsif ($entry->can('get_data')) {
        # use Value object methods...
    }
    elsif ($entry->can('get_security_descriptor')) {
        # use Security object methods...
    }

$entry->get_offset
    Returns the position of the entry relative to the start of the file.

$entry->get_length
    Returns the length of the entry.

$entry->get_tag
    Returns a string containing a descriptive tag for the entry.

    For Windows NT registry entries, the tags reflect the signatures used to identify them. These are: 'nk' for keys; 'vk' for values; 'sk' for security entries; and 'lf', 'lh', 'li', or 'ri' for subkey lists. Entries that do not have signatures will return an empty string. Unidentified entries include value lists, value data, and the class names of keys.

    For Windows 95 registry files, the tag reflects which part of the registry file the entry is from, and will be 'rgkn key', 'rgdb key', or 'rgdb value'.

$entry->is_allocated
    Returns a boolean value indicating the 'allocated' state of a Windows NT registry entry.

    This value has no meaning for Windows 95 registry entries.

$entry->as_string
    Returns a string representation of the entry.

    If the entry is a valid Key, Value, or Security object, then as_string will call the as_string method of that object.

$entry->parse_info
    Returns a string containing a summary of the parser information for that entry.

    If the entry is a valid Key, Value, or Security object, then parse_info will call the parse_info method of that object.

$entry->unparsed
    Returns a string containing a hex dump of the unparsed on-disk data for the entry.

$entry->get_raw_bytes
    Returns the unparsed on-disk data for the entry.

SCRIPTS
All of the supplied scripts are intended to be used either as tools or as examples for you to modify and develop.

Try regdump.pl or regshell.pl to look at a registry file from the command line, or gtkregview.pl or wxregview.pl if you want a GUI. If you want to compare registry files, try regmultidiff.pl from the command line or gtkregcompare.pl or wxregcompare.pl if you want a GUI. You can edit the scripts to customize them for your own requirements.

If you specify subkeys on the command line, note that you need to quote the subkey on Windows if it contains spaces:

    regdump.pl ntuser.dat "software\microsoft\windows nt"

You will also need to quote backslashes and spaces in Unix shells:

    regdump.pl ntuser.dat software\\microsoft\\windows\ nt

or use single quotes:

    regdump.pl ntuser.dat 'software\microsoft\windows nt'

  gtkregcompare.pl
gtkregcompare.pl is a GTK+ program for comparing multiple registry files. It displays a tree of the registry keys and values highlighting those that have changed.

It requires Gtk2-Perl to be installed.

Filenames of registry files to compare can be supplied on the command line:

    gtkregcompare.pl <filename1> <filename2> <filename3> ...

You can of course use wildcards when running from a Unix shell.

  gtkregscope.pl
gtkregscope.pl is a GTK+ registry scanner. It presents all the entries in a registry file returned by the get_block_iterator and get_entry_iterator methods. It uses color to highlight key, value, security, and subkey list entries, and presents the block as a colored map.

It requires Gtk2-Perl to be installed.

A filename can also be supplied on the command line:

    gtkregscope.pl <filename>

  gtkregview.pl
gtkregview.pl is a GTK+ registry viewer. It displays a tree of registry keys on the left hand side, a list of values on the right, and a hex dump of the selected value data at the bottom.

It requires Gtk2-Perl to be installed.

A filename can also be supplied on the command line:

    gtkregview.pl <filename>

  regclassnames.pl
regclassnames.pl will display registry keys that have class names. Only a very few Windows NT registry key have class names.

Type regclassnames.pl on its own to see the help:

    regclassnames.pl <filename> [subkey]

  regdump.pl
regdump.pl is used to display the keys and values of a registry file.

Type regdump.pl on its own to see the help:

    regdump.pl <filename> [subkey] [-r] [-v] [-x] [-c] [-s] [-o]
        -r or --recurse     traverse all child keys from the root key
                            or the subkey specified
        -v or --values      display values
        -x or --hexdump     display value data as a hex dump
        -c or --class-name  display the class name for the key (if present)
        -s or --security    display the security information for the key,
                            including the owner and group SIDs,
                            and the system and discretionary ACLs (if present)
        -o or --owner       display the owner SID for the key (if present)

The contents of the root key will be displayed unless a subkey is specified. Paths to subkeys are always specified relative to the root key. By default, only the subkeys and values immediately underneath the specified key will be displayed. To display all keys and values beneath a key, use the -r or --recurse option.

For example, regdump.pl ntuser.dat might display the following:

    $$$PROTO.HIV  [2005-01-01T09:00:00Z]
    ..\AppEvents
    ..\Console
    ..\Control Panel
    ..\Environment
    ..\Identities
    ..\Keyboard Layout
    ..\Printers
    ..\Software
    ..\UNICODE Program Groups

From here, you can explore the subkeys to find those keys or values you are interested in:

    regdump.pl ntuser.dat software
    regdump.pl ntuser.dat software\microsoft
    ...

  regexport.pl
regexport.pl will display registry keys and values in the Windows Registry Editor Version 5.00 format used by REGEDIT on Windows 2000 and later.

Type regexport.pl on its own to see the help:

    regexport.pl <filename> [subkey] [-r]
        -r or --recurse     traverse all child keys from the root key
                            or the subkey specified

Values are always shown for each key displayed.

Subkeys are displayed as comments when not recursing. (Comments are preceded by the ';' character.)

  regfind.pl
regfind.pl is used to search the keys, values, data, or types of a registry file for a matching string.

Type regfind.pl on its own to see the help:

    regfind.pl <filename> <search-string> [-k] [-v] [-d] [-t] [-x]
        -k or --key         search key names for a match
        -v or --value       search value names for a match
        -d or --data        search value data for a match
        -t or --type        search value types for a match
        -x or --hexdump     display value data as a hex dump

To search for the string "recent" in the names of any keys or values:

    regfind.pl ntuser.dat recent -kv

To search for the string "administrator" in the data of any values:

    regfind.pl ntuser.dat administrator -d

To list all REG_MULTI_SZ values:

    regfind.pl ntuser.dat -t multi_sz

Search strings are not case-sensitive.

  regml.pl
regml.pl will display those keys with explicit System Mandatory Label ACEs set in the System ACL. This feature was introduced with Windows Vista, and is used by applications such as Internet Explorer running in Protected Mode. Note that if a key does not have an explicit System Mandatory Label ACE, it has Medium Integrity Level. Only Windows NT registry files can contain System Mandatory Label ACEs.

Type regml.pl on its own to see the help:

    regml.pl <filename>

  regmultidiff.pl
regmultidiff.pl can be used to compare multiple registry files and identify the differences between them.

Type regmultidiff.pl on its own to see the help:

    regmultidiff.pl <file1> <file2> <file3> ... [<subkey>] [-v] [-x] [-l] [-a]
        -v or --values      display values
        -x or --hexdump     display value data as a hex dump
        -l or --long        show each changed key or value instead of a summary
        -a or --all         show all keys and values before and after a change

You can limit the comparison by specifying an initial subkey.

  regscan.pl
regscan.pl dumps all the entries in a registry file. This will include defunct keys and values that are no longer part of the current active registry.

Type regscan.pl on its own to see the help:

    regscan.pl <filename> [-k] [-v] [-s] [-a] [-p] [-u] [-w]
        -k or --keys        list only 'key' entries
        -v or --values      list only 'value' entries
        -s or --security    list only 'security' entries
        -a or --allocated   list only 'allocated' entries
        -p or --parse-info  show the technical information for an entry
                            instead of the string representation
        -u or --unparsed    show the unparsed on-disk entries as a hex dump

  regsecurity.pl
regsecurity.pl will display the security information contained in a registry files. Only Windows NT registry files contain security information.

Type regsecurity.pl on its own to see the help:

    regsecurity.pl <filename>

  regshell.pl
Provides an interactive command shell where you navigate through the keys using 'cd' to change the current key and 'ls' or 'dir' to list the contents of the current key.

Tab completion of subkey and value names is available. Names containing spaces are supported by quoting names with " characters. Note that names are case sensitive.

A filename should be supplied on the command line:

    regshell.pl <filename>

Once regshell.pl is running, type help to see the available commands.

It requires Term::ReadLine to be installed.

  regstats.pl
regstats.pl counts the number of keys and values in a registry file. It will also provide a count of each value type if requested.

Type regstats.pl on its own to see the help:

    regstats.pl <filename> [-t]
        -t or --types       count value types

  regtimeline.pl
regtimeline.pl displays keys and values in date order.

As only Windows NT based registry keys provide timestamps, this script only works on Windows NT registry files.

You can limit the display to a given number of days (counting back from the timestamp of the last key).

Type regtimeline.pl on its own to see the help:

    regtimeline.pl <filename> [subkey] [-l <number>] [-v] [-x]
        -l or --last        display only the last <number> days
                            of registry activity
        -v or --values      display values
        -x or --hexdump     display value data as a hex dump

  regtree.pl
regtree.pl simply displays the registry as an indented tree, optionally displaying the values of each key.

Type regtree.pl on its own to see the help:

    regtree.pl <filename> [subkey] [-v]
        -v or --values      display values

  wxregcompare.pl
wxregcompare.pl is a wxWidgets program for comparing multiple registry files. It displays a tree of the registry keys and values, highlighting those that have changed.

It requires wxPerl to be installed.

Filenames of registry files to compare can be supplied on the command line:

    wxregcompare.pl <filename1> <filename2> <filename3> ...

You can of course use wildcards when running from a Unix shell.

  wxregscope.pl
wxregscope.pl is a wxWidgets registry scanner. It presents all the entries in a registry file returned by the get_block_iterator and get_entry_iterator methods. It uses color to highlight key, value, security, and subkey list entries.

It requires wxPerl to be installed.

A filename can also be supplied on the command line:

    wxregscope.pl <filename>

  wxregview.pl
wxregview.pl is a wxWidgets registry viewer. It displays a tree of registry keys on the left hand side, a list of values on the right, and a hex dump of the selected value data at the bottom. It can also provide a timeline view of all of the registry keys, which can be used to navigate the main tree view by clicking or double-clicking on a timeline key.

It requires wxPerl to be installed.

A filename can also be supplied on the command line:

    wxregview.pl <filename>

ACKNOWLEDGEMENTS
This would not have been possible without the work of those people who have analysed and shared their knowledge of the structure of Windows Registry files, primarily: B.D. (WinReg.txt), Petter Nordahl-Hagen (chntpw), and Richard Sharpe and Jerry Carter (Samba 3).

AUTHOR
James Macfarlane, <jmacfarla@cpan.org>

COPYRIGHT AND LICENSE
Copyright (C) 2006-2012 by James Macfarlane

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.

THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.