diff options
Diffstat (limited to 'contrib/ldaptcl/ldap.n')
| -rw-r--r-- | contrib/ldaptcl/ldap.n | 395 |
1 files changed, 395 insertions, 0 deletions
diff --git a/contrib/ldaptcl/ldap.n b/contrib/ldaptcl/ldap.n new file mode 100644 index 0000000..cc0d2df --- /dev/null +++ b/contrib/ldaptcl/ldap.n @@ -0,0 +1,395 @@ +'\" +'\" Copyright (c) 1998 NeoSoft, Inc. +'\" +'\" See the file "license.terms" for information on usage and redistribution +'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES. +'\" +.so man.macros +.TH ldap n "" Ldap "Ldap Tcl Extension" +.BS +'\" Note: do not modify the .SH NAME line immediately below! +.SH NAME +ldap \- connect to and query an LDAP server +.SH SYNOPSIS +\fBldap \fBopen \fR \fIcommand\fR \fIhostlist\fR +.br +\fBldap \fBinit \fR \fIcommand\fR \fIhostlist\fR ?protocol_version [2|3]? +.br +\fBldap \fBexplode ?-nonames|-list?\fR \fIdn\fR +.br +\fIcommand \fBsubcommand \fIoptions ...\fR +.BE + +.SH OVERVIEW +.PP +A new command by the name of \fIcommand\fR will be created to access +the LDAP database at \fIhostlist\fR. \fIhostlist\fR may contain elements +of the format \fBhost:port\fR if a port other than the default LDAP port +of 389 is required. The LDAP library will attempt to connect to each +host in turn until it succeeds or exhausts the list. +.PP +The \fBexplode\fR form provides a means (via ldap_explode(3)) to explode a DN +into its component parts. \fB-nonames\fR strips off the attribute names, +and -list returns a list suitable for \fBarray set\fR. +.PP +Finally, the last form, described in more detail below, refers genericly +to how the command created by the first two examples is used. +.SH DESCRIPTION + +The Lightweight Directory Access Protocol provides TCP/IP access to +X.500 directory services and/or to a stand-alone LDAP server. + +This code provides a Tcl interface to the +Lightweight Directory Access Protocol package using the Netscape +Software Development Kit. It can also be used with the freely +redistributable University of +Michigan (http://www.umich.edu/~rsug/ldap) version by defining the +UMICH_LDAP macro during compilation. + +.SH CONNECTING TO AN LDAP SERVER + +To create an ldap interface entity, we use the "ldap" command. + + ldap open foo foo.bar.com + +This opens a connection to a LDAP server on foo.bar.com, and makes +a new Tcl command, foo, through which we will manipulate the interface +and make queries to the remote LDAP server. + + ldap init foo foo.bar.com + +Same as above, foo is created, but for "init", opening the connection is +deferred until we actually try to do something. + +The init command also allows some optional values to be set for the connection. +Currently, the only useful option is \fBprotocol_version\fR which take a +single argument to specify to use LDAP protocol 2 or 3. This may be required +when connecting to older LDAP server. + +For the purposes of this example, we're going to assume that "foo" is the +command created by opening a connection using "ldap open". + +.SH BINDING + +After a connection is made to an LDAP server, an LDAP bind operation must +be performed before other operations can be attempted over the connection. + +Both simple authentication and kerberos authentication are available. +LDAP version 3 supports many new "SSL"-style authentication and encryption +systems, which are not currently supported by the OpenLDAP v1.2 server, and +hence by this interface package. + +Currently simple and kerberos-based authentication, are supported. + +To use LDAP and still have reasonable security in a networked, +Internet/Intranet environment, secure shell can be used to setup +secure, encrypted connections between client machines and the LDAP +server, and between all LDAP nodes that might be used. + +To perform the LDAP "bind" operation: + + foo bind simple dn password + + foo bind kerberos_ldap + foo bind kerberos_dsa + foo bind kerberos_both + +It either returns nothing (success), or a Tcl error with appropriate error +text. + +For example, + + foo bind simple "cn=Manager,o=NeoSoft Inc,c=us" "secret" + +If you attempt to bind with one of the kerberos authentication types +described above and your LDAP library was not built with KERBEROS +defined, you will get an unknown auth type error. + +To unbind an LDAP connection previously bound with "bind": + + foo unbind + +Note that unbinding also deletes the command (\fBfoo\fR in this case). +Deleting the command has the same affect. + +The ability of the library to callback to the client, enabling re-binding +while following referrals, is not currently supported. + +.SH DELETING OBJECTS + +To delete an object in the LDAP database, use + + foo delete dn + +To rename an object to another relative distinguished name, use + + foo rename_rdn dn rdn + +To rename an object to another relative distinguished name, leaving +the old entry as some kind of attribute (FIX: not sure if this is +right or how it works) + + foo modify_rdn dn rdn + + +.SH ADDING NEW OBJECTS + + foo add dn attributePairList + +This creates a new distinguished name and defines zero or more attributes. + +"attributePairList" is a list of key-value pairs, the same as would +be returned by "array get" if an array had been set up containing the +key-value pairs. + + foo add "cn=karl, ou=People, o=NeoSoft Inc, c=US" {cn karl ...} + +Some directory servers and/or their client SDKs will automatically +add the leaf attribute value for you. + +Here is a more precise description of how an attributePairList looks: + + {cn {karl {Karl Lehenbauer}} telephone 713-968-5800} + +Note here that two cn values, "karl" and "Karl Lehenbauer", are added. +Is it an error to write: + + {cn {Karl Lehenbauer}} + +Which adds two cn values, "Karl" and "Lehenbauer", when the intention +was to give a single cn value of "Karl Lehenbauer". In real life, one +finds oneself making prodigous use of the \fBlist\fR command rather than +typing hard-coded lists. + +We have noticed that the Netscape server will automatically add the +left-most rdn portion of the DN (ie. cn=karl), whereas the University +of Michigan and OpenLDAP 1.2 versions do not. + +.SH ADDING, DELETING, AND REPLACING OBJECT ATTRIBUTES + +You can have multiple values for a given attribute in an LDAP object. +These are represented in search results, through the Tcl interface, +as a list. + + foo add_attributes dn attributePairList + +This adds key-value pairs to an existing DN. If an attribute being +added already exists, the new value will be appended to the list. +If a particular value being added to an attribute already exists in +the object a Tcl error is raised. + + foo replace_attributes dn attributePairList + +This replaces the specified attributes in an existing DN, leaving +unnamed ones untouched. Any previous values for the supplied attributes +(if any) are discarded. + + foo delete_attributes dn attributePairList + +This deletes attributes in the list. If an attribute "foo" has the +value list {bar snap}, and you delete using the attributePairList "foo bar", +"foo" will still have "snap". + +If you provide an empty string ("") for the value list, +the entire attribute will be deleted. + +In Ldaptcl version 2.0, multiple operations may be combined into a single +transaction, ie. as in: + + foo add_attributes dn attributePairList replace attributePairList \ + delete attributePairList + +.SH SEARCHING + +The Tcl interface to searching takes a control array, which contains +a couple of mandatory key-value pairs, and can contain a number of +optional key-value pairs as well, for controlling the search, a +destination array, into which the specified attributes (or all attributes +of matching DNs if none are specified) and values are stored. + +The "code" part is executed repeatedly, once for each DN matching the +search criteria. + +.nf + foo search controlArray destArray code + + Using data in the control array, a search is performed of the + LDAP server opened when foo was created. Possible elements + of the control array are enumerated blow. + + controlArray(base) is the DN being searched from. (required) + + controlArray(filter) contains the search criteria. (required) + + controlArray(scope) must be "base", "one_level", or "subtree". + If not specified, scope defaults to "subtree". + + controlArray(deref) must be "never", "search", "find", or "always" + If not specified, deref defaults to "never" + + controlArray(attributes) is a list of attributes to be fetched. + If not specified, all attributes are fetched. + + controlArray(timeout) a timeout value in seconds (may contain + fractional values -- extremely very small values are useful + for forcing timeout conditions to test timeouts). +.fi + +For each matching record, destArray is populated with none, +some or all attribute-value pairs as determined by the request and +access control lists on the server. + +Note: There are some additional parameters that can be set, such as +how long the synchronous version of the routines should wait before +timing out, the interfaces for which are not available in the current +version. + +.SH COMPARE + + foo compare dn attribute value + +Interface to the ldap_compare_s() command. +Compares the value of \fIattribute\fR in the object at \fIdn\fR to the +\fIvalue\fR given in the command line. Returns an error if \fIdn\fR +does not exist. Otherwise, a + +.SH CACHING (Note: Netscape clients do not have caching interfaces). + +The UMich and OpenLDAP client libraries offers the client application fairly +fine-grained control of caching of results retrieved from searches, +offering significant performance improvement and reduced +network traffic. + +By default, the cache is disabled. + +To enable caching of data received from an LDAP connection, + + foo cache enable timeout maxmem + + ...where timeout is specified in seconds, and maxmem is the + maximum memory to be used for caching, in bytes. + + If maxmem is 0, the cache size is restricted only by the timeout. + + foo cache disable + + ...temporarily inhibits use of the cache (while disabled, new requests + are not cached and the cache is not checked when returning results). + + Disabling the cache does not delete its contents. + + foo cache destroy + + ...turns off caching and completely removes the cache from memory. + + foo cache flush + + ...deletes the entire cache contents, but does not affect + whether or not the cache is being used. + + foo cache uncache dn + + ...removes from the cache all request results that make reference + to the specified DN. + + This should be used, for example, after doing an add_attributes, + delete_attributes, or replace_attributes (ldap_modify(3)) + involving the requested DN. Generally this should not be needed, + as the Tcl interface automatically performs this operation on + any dn that is modified (add,replace,delete) while caching is + enabled. + + foo cache no_errors + + ...suppresses caching of any requests that result in an error. + + foo cache size_errors + + ...suppresses caching of any requests that result in an error, + except for requests resulting in "sizelimit exceeded", which + are cached. This is the default. + + foo cache all_errors + + ...enables caching of all requests, including those that result + in errors. + +.SH IMPLEMENTATION DECISIONS + +Because we used the new "Tcl object" C interfaces, this package only works +with Tcl 8.0 or above. + +This package interfaces with the University of Michigan LDAP protocol +package, version 3.3, and OpenLDAP version 1.2, both of which are +implementations of version 2 of the LDAP protocol. + +Although an LDAP client (or server) could be written in native Tcl 8.0, +as Tcl 8.0 and above can do binary I/O, and Tcl 8 and above have strings +that are fully eight-bit clean, for a first implementation, to minimize +compatibility problems, we created a C interface to the UMich LDAP library. + +A native Tcl implementation would be cool because we could bring the receiving +of messages into the normal Tcl event loop and run the LDAP interface fully +asynchronous. + +This implementation is blocking, and blocking only. That is to say that +the Tcl event loop is frozen while the ldap routines are waiting on data. + +This could be fixed either by recoding all of the I/O in the LDAP library +to use Tcl's I/O system instead, or by simply coding the LDAP interface in +native Tcl, as mentioned above. + +Another advantage of coding in high-level Tcl, of course, is that the +client would immediately be cross-platform to Windows and the Mac, as +well as Unix. + +Binary data is not currently supported. It will probably be trivial to +add, we just haven't dug into it yet. + + +.SH FOR MORE INFORMATION + +This document principally describes how to use our Tcl interface to the +LDAP library works. + +For more information on LDAP and the University of Michigan LDAP package, +please visit the website mentioned above. The package includes substantial +documentation in the form of UNIX manual pages, a SLAPD/SLURPD guide +in Adobe Portable Document Format (pdf), and a number of Internet RFCs +related to LDAP services. + +.SH AUTHORS +It was written by Karl Lehenbauer, of NeoSoft, Inc., in August and +September of 1997. Ldap explode, and numerous bug fixes and extensions +by Randy Kunkee, also of NeoSoft, Inc., in 1998-1999. + +.SH KEYWORDS +element, join, list, separator +.SH BUGS +The \fBldap init\fR syntax fails to return anything useful. Use +\fBldap open\fR instead. + +\fBPackage require Ldaptcl\fR won't work unless the ldap and lber libraries +are also shared, and ldaptcl.so is itself created with the correct flags +(eg. -R for Solaris). In short there's a lot of details to make this part +work, but it should work out of the box for Solaris. Other systems may +require that LD_LIBRARY_PATH or other appropraite environment variables +be set at build and/or runtime. + +An asynchronous interface should be provided with callbacks. + +We have never tested Kerberos authentication. + +It does not tolerate some illegal operations very well. + +It is possible to create empty attributes, ie. attributes which are present +but have no value. This is done by deleting the attribute values rather +than, eg. "foo delete_attributes dn {telephone {}}" which would delete +the telephone attribute altogether. A search for presence of the attribute +may return an object, and yet it may have no value. This interface presents +such an object as not having the attribute at all (ie. you cannot tell). +The Netscape SDK does this for you, so this makes the behavior consistent +when using UMICH_LDAP. + +\--enable-netscape configuration support has not been tested and probably +has bugs. |