25.4. Data Handling in the LDAP Directory

OpenLDAP offers a series of tools for the administration of data in the LDAP directory. The four most important tools for adding to, deleting from, searching through, and modifying the data stock are briefly explained below.

25.4.1. Inserting Data into an LDAP Directory

Once the configuration of your LDAP server in /etc/openldap/lsapd.conf is correct and ready to go (it features appropriate entries for suffix, directory, rootdn, rootpw, and index), proceed to entering records. OpenLDAP offers the ldapadd command for this task. If possible, add the objects to the database in bundles for practical reasons. LDAP is able to process the LDIF format (LDAP data interchange format) for this. An LDIF file is a simple text file that can contain an arbitrary number of pairs of attribute and value. Refer to the schema files declared in slapd.conf for the available object classes and attributes. The LDIF file for creating a rough framework for the example in Figure 25.1, “Structure of an LDAP Directory” would look like that in Example 25.7, “Example for an LDIF File”.

Example 25.7. Example for an LDIF File

# The SUSE Organization
dn: dc=suse,dc=de
objectClass: dcObject
objectClass: organization
o: SUSE AG dc: suse

# The organizational unit development (devel)
dn: ou=devel,dc=suse,dc=de
objectClass: organizationalUnit
ou: devel

# The organizational unit documentation (doc)
dn: ou=doc,dc=suse,dc=de
objectClass: organizationalUnit
ou: doc

# The organizational unit internal IT (it)
dn: ou=it,dc=suse,dc=de
objectClass: organizationalUnit
ou: it
[Important]Encoding of LDIF Files

LDAP works with UTF-8 (Unicode). Umlauts must be encoded correctly. Use an editor that supports UTF-8, such as Kate or recent versions of Emacs. Otherwise, avoid umlauts and other special characters or use recode to recode the input to UTF-8.

Save the file with the .ldif suffix then pass it to the server with the following command:

ldapadd -x -D <dn of the administrator> -W -f <file>.ldif

-x switches off the authentication with SASL in this case. -D declares the user that calls the operation. The valid DN of the administrator is entered here just like it has been configured in slapd.conf. In the current example, this is cn=admin,dc=suse,dc=de. -W circumvents entering the password on the command line (in clear text) and activates a separate password prompt. This password was previously determined in slapd.conf with rootpw. -f passes the filename. See the details of running ldapadd in Example 25.8, “ldapadd with example.ldif”.

Example 25.8. ldapadd with example.ldif

ldapadd -x -D cn=admin,dc=suse,dc=de -W -f example.ldif 

Enter LDAP password: 
adding new entry "dc=suse,dc=de" 
adding new entry "ou=devel,dc=suse,dc=de" 
adding new entry "ou=doc,dc=suse,dc=de" 
adding new entry "ou=it,dc=suse,dc=de"

The user data of individuals can be prepared in separate LDIF files. Example 25.9, “LDIF Data for Tux” adds Tux to the new LDAP directory.

Example 25.9. LDIF Data for Tux

# coworker Tux
dn: cn=Tux Linux,ou=devel,dc=suse,dc=de
objectClass: inetOrgPerson
cn: Tux Linux
givenName: Tux
sn: Linux
mail: tux@suse.de
uid: tux
telephoneNumber: +49 1234 567-8

An LDIF file can contain an arbitrary number of objects. It is possible to pass entire directory branches to the server at once or only parts of it as shown in the example of individual objects. If it is necessary to modify some data relatively often, a fine subdivision of single objects is recommended.

25.4.2. Modifying Data in the LDAP Directory

The tool ldapmodify is provided for modifying the data stock. The easiest way to do this is to modify the corresponding LDIF file then pass this modified file to the LDAP server. To change the telephone number of colleague Tux from +49 1234 567-8 to +49 1234 567-10, edit the LDIF file like in Example 25.10, “Modified LDIF File tux.ldif”.

Example 25.10. Modified LDIF File tux.ldif

# coworker Tux
dn: cn=Tux Linux,ou=devel,dc=suse,dc=de 
changetype: modify
replace: telephoneNumber 
telephoneNumber: +49 1234 567-10

Import the modified file into the LDAP directory with the following command:

ldapmodify -x -D cn=admin,dc=suse,dc=de -W -f tux.ldif

Alternatively, pass the attributes to change directly to ldapmodify. The procedure for this is described below:

  1. Start ldapmodify and enter your password:

    ldapmodify -x -D cn=admin,dc=suse,dc=de -W 
    Enter LDAP password:
    
  2. Enter the changes while carefully complying with the syntax in the order presented below:

    dn: cn=Tux Linux,ou=devel,dc=suse,dc=de
    changetype: modify
    replace: telephoneNumber
    telephoneNumber: +49 1234 567-10

Find detailed information about ldapmodify and its syntax in the ldapmodify(1) man page.

25.4.3. Searching or Reading Data from an LDAP Directory

OpenLDAP provides, with ldapsearch, a command line tool for searching data within an LDAP directory and reading data from it. A simple query would have the following syntax:

ldapsearch -x -b dc=suse,dc=de "(objectClass=*)"

The option -b determines the search base—the section of the tree within which the search should be performed. In the current case, this is dc=suse,dc=de. To perform a more finely-grained search in specific subsections of the LDAP directory (for example, only within the devel department), pass this section to ldapsearch with -b. -x requests activation of simple authentication. (objectClass=*) declares that all objects contained in the directory should be read. This command option can be used after the creation of a new directory tree to verify that all entries have been recorded correctly and the server responds as desired. More information about the use of ldapsearch can be found in the corresponding man page (ldapsearch(1)).

25.4.4. Deleting Data from an LDAP Directory

Delete unwanted entries with ldapdelete. The syntax is similar to that of the commands described above. To delete, for example, the complete entry for Tux Linux, issue the following command:

ldapdelete -x -D cn=admin,dc=suse,dc=de -W cn=Tux \
Linux,ou=devel,dc=suse,dc=de