-.TH SLAPD_META 5 "28 April 2002" "OpenLDAP LDVERSION"
-.\" Copyright 1998-2002 The OpenLDAP Foundation, All Rights Reserved.
+.TH SLAPD-META 5 "RELEASEDATE" "OpenLDAP LDVERSION"
+.\" Copyright 1998-2003 The OpenLDAP Foundation, All Rights Reserved.
.\" Copying restrictions apply. See the COPYRIGHT file.
.\" Copyright 2001, Pierangelo Masarati, All rights reserved. <ando@sys-net.it>
.\" $OpenLDAP$
.\" and maybe manual pages for librewrite.
.\"
.SH NAME
-slapd_meta \- metadirectory backend
+slapd-meta \- metadirectory backend
.SH SYNOPSIS
ETCDIR/slapd.conf
.SH DESCRIPTION
belonging to a single Directory Information Tree (DIT).
.LP
A basic knowledge of the functionality of the
-.BR slapd_ldap (5)
+.BR slapd\-ldap (5)
backend is recommended.
This backend has been designed as an enhancement of the ldap backend.
The two backends share many features (actually they also share
carefully considered.
In the examples section, some typical scenarios will be discussed.
.SH EXAMPLES
-There are examples various places in this document, as well as in the
+There are examples in various places in this document, as well as in the
slapd/back-meta/data/ directory in the OpenLDAP source tree.
.SH CONFIGURATION
-The
-.BR slapd.conf (5)
-options in this category apply to the META backend database.
+These
+.B slapd.conf
+options apply to the META backend database.
That is, they must follow a "database meta" line and come before any
subsequent "backend" or "database" lines.
+Other database options are described in the
+.BR slapd.conf (5)
+manual page.
.LP
Note: as with the
.B ldap
While code to strip the modification attributes has been put in place
(and #ifdef'd), it implies unmotivated overhead.
So it is strongly recommended to set
-.LP
-.nf
- lastmod off
-.fi
-.LP
+.RS
+lastmod off
+.RE
for every
.B ldap
and
.B meta
backend.
-.SH "SPECIAL CONFIGURATION DIRECTIVES"
+.SH SPECIAL CONFIGURATION DIRECTIVES
Target configuration starts with the "uri" directive.
All the configuration directives that are not specific to targets
should be defined first for clarity, including those that are common
They include: add, delete, modify, modrdn; compare is not included, as
well as bind since, as they don't alter entries, in case of multiple
matches an attempt is made to perform the operation on any candidate
-target, with the constraint that at most on must succeed.
+target, with the constraint that at most one must succeed.
This directive can also be used when processing targets to mark a
specific target as default.
.TP
.B dncache-ttl {forever|disabled|<ttl>}
-This directive sets the time-to-live of the dn cache.
-This caches the target that holds a given dn to speed up target
+This directive sets the time-to-live of the DN cache.
+This caches the target that holds a given DN to speed up target
selection in case multiple targets would result from an uncached
-search; forever means cache never expires; disabled means no dn
+search; forever means cache never expires; disabled means no DN
caching; otherwise a valid ( > 0 ) ttl in seconds is required.
-.SH "TARGET SPECIFICATION"
+.SH TARGET SPECIFICATION
Target specification starts with a "uri" directive:
.TP
.B uri <protocol>://[<host>[:<port>]]/<naming context>
The "server" directive that was allowed in the LDAP backend (although
deprecated) has been discarded in the Meta backend.
-The <protocol> part can be anything ldap_initialize(3) accepts
-({ldap|ldaps|ldapi} and variants); <host> and <port> may be omitted,
-defaulting to whatever is set in /etc/ldap.conf (correct me!?!).
+The <protocol> part can be anything
+.BR ldap_initialize (3)
+accepts ({ldap|ldaps|ldapi} and variants); <host> and <port> may be
+omitted, defaulting to whatever is set in /etc/ldap.conf.
The <naming context> part is mandatory.
It must end with one of the naming contexts defined for the backend,
e.g.:
.LP
+.RS
.nf
- suffix "dc=foo,dc=com"
- uri "ldap://x.foo.com/dc=x,dc=foo,dc=com"
+suffix "\fBdc=foo,dc=com\fP"
+uri "ldap://x.foo.com/dc=x,\fBdc=foo,dc=com\fP"
.fi
+.RE
.LP
The <naming context> part doesn't need to be unique across the targets;
it may also match one of the values of the "suffix" directive.
+Multiple URIs may be defined in a single argument. The URIs must
+be separated by TABs (e.g. '\\t'), and the additional URIs must have
+no <naming context> part. This causes the underlying library
+to contact the first server of the list that responds.
.TP
.B default-target [<target>]
The "default-target" directive can also be used during target specification.
from 1.
Target <target> must be defined.
.TP
-.B binddn <administrative dn for ac purposes>
-This directive, as in the LDAP backend, allows to define the dn that is
+.B binddn "<administrative DN for access control purposes>"
+This directive, as in the LDAP backend, allows to define the DN that is
used to query the target server for acl checking; it should have read
access on the target server to attributes used on the proxy for acl
checking.
There is no risk of giving away such values; they are only used to
check permissions.
.TP
-.B bindpw <password for ac purposes>
+.B bindpw <password for access control purposes>
This directive sets the password for acl checking in conjunction
with the above mentioned "binddn" directive.
.TP
-.B pseudorootdn <substitute dn in case of rootdn bind>
-This directive, if present, sets the dn that will be substituted to
-the bind dn if a bind with the backend's "rootdn" succeeds.
+.B rebind-as-user
+If this option is given, the client's bind credentials are remembered
+for rebinds when chasing referrals.
+.TP
+.B pseudorootdn "<substitute DN in case of rootdn bind>"
+This directive, if present, sets the DN that will be substituted to
+the bind DN if a bind with the backend's "rootdn" succeeds.
The true "rootdn" of the target server ought not be used; an arbitrary
-administrative dn should used instead.
+administrative DN should used instead.
.TP
-.B pseudorootpw <substitute password in case of rootdn bind>
+.B pseudorootpw "<substitute password in case of rootdn bind>"
This directive sets the credential that will be used in case a bind
with the backend's "rootdn" succeeds, and the bind is propagated to
-the target using the "pseudorootdn" dn.
+the target using the "pseudorootdn" DN.
+.LP
+Note: cleartext credentials must be supplied here; as a consequence,
+using the pseudorootdn/pseudorootpw directives is inherently unsafe.
.TP
.B rewrite* ...
The rewrite options are described in the "REWRITING" section.
.TP
-.B suffixmassage <virtual naming context> <real naming context>
+.B suffixmassage "<virtual naming context>" "<real naming context>"
All the directives starting with "rewrite" refer to the rewrite engine
that has been added to slapd.
The "suffixmassage" directive was introduced in the LDAP backend to
.LP
See the "REWRITING" section.
.TP
-.B map {objectClass|attribute} {<source>|*} [<dest>|*]
+.B map "{attribute|objectclass} [<local name>|*] {<foreign name>|*}"
This maps object classes and attributes as in the LDAP backend.
See
.BR slapd-ldap (5).
-.SH "SCENARIOS"
+.SH SCENARIOS
A powerful (and in some sense dangerous) rewrite engine has been added
to both the LDAP and Meta backends.
While the former can gain limited beneficial effects from rewriting
say "dc=a,dc=foo,dc=com" and "dc=b,dc=foo,dc=com".
Then, an unambiguous Meta database can be configured as:
.LP
+.RS
.nf
- database meta
- suffix "dc=foo,dc=com"
- uri "ldap://a.foo.com/dc=a,dc=foo,dc=com"
- uri "ldap://b.foo.com/dc=b,dc=foo,dc=com"
+database meta
+suffix "\fBdc=foo,dc=com\fP"
+uri "ldap://a.foo.com/dc=a,\fBdc=foo,dc=com\fP"
+uri "ldap://b.foo.com/dc=b,\fBdc=foo,dc=com\fP"
.fi
+.RE
.LP
Operations directed to a specific target can be easily resolved
because there are no ambiguities.
spawning two searches to the targets.
.LP
2a) Two directory servers don't share any portion of naming context,
-but they'd present as a single DIT.
+but they'd present as a single DIT
[Caveat: uniqueness of (massaged) entries among the two servers is
assumed; integrity checks risk to incur in excessive overhead and have
-not been implemented.] Say we have "dc=bar,dc=org" and "o=Foo,c=US",
+not been implemented].
+Say we have "dc=bar,dc=org" and "o=Foo,c=US",
and we'd like them to appear as branches of "dc=foo,dc=com", say
"dc=a,dc=foo,dc=com" and "dc=b,dc=foo,dc=com".
Then we need to configure our Meta backend as:
.LP
+.RS
.nf
- database meta
- suffix "dc=foo,dc=com"
-
- uri "ldap://a.bar.com/dc=a,dc=foo,dc=com"
- suffixmassage "dc=a,dc=foo,dc=com" "dc=bar,dc=org"
-
- uri "ldap://b.foo.com/dc=b,dc=foo,dc=com"
- suffixmassage "dc=b,dc=foo,dc=com" "o=Foo,c=US"
+database meta
+suffix "dc=foo,dc=com"
+
+uri "ldap://a.bar.com/\fBdc=a,dc=foo,dc=com\fP"
+suffixmassage "\fBdc=a,dc=foo,dc=com\fP" "dc=bar,dc=org"
+
+uri "ldap://b.foo.com/\fBdc=b,dc=foo,dc=com\fP"
+suffixmassage "\fBdc=b,dc=foo,dc=com\fP" "o=Foo,c=US"
.fi
+.RE
.LP
Again, operations can be resolved without ambiguity, although
some rewriting is required.
2b) Consider the above reported scenario with the two servers
sharing the same naming context:
.LP
+.RS
.nf
- database meta
- suffix "dc=foo,dc=com"
-
- uri "ldap://a.bar.com/dc=foo,dc=com"
- suffixmassage "dc=foo,dc=com" "dc=bar,dc=org"
-
- uri "ldap://b.foo.com/dc=foo,dc=com"
- suffixmassage "dc=foo,dc=com" "o=Foo,c=US"
+database meta
+suffix "\fBdc=foo,dc=com\fP"
+
+uri "ldap://a.bar.com/\fBdc=foo,dc=com\fP"
+suffixmassage "\fBdc=foo,dc=com\fP" "dc=bar,dc=org"
+
+uri "ldap://b.foo.com/\fBdc=foo,dc=com\fP"
+suffixmassage "\fBdc=foo,dc=com\fP" "o=Foo,c=US"
.fi
+.RE
.LP
All the previous considerations hold, except that now there is
no way to unambiguously resolve a DN.
In this case, all the operations that require an unambiguous target
-selection will fail unless the dn is already cached or a default
+selection will fail unless the DN is already cached or a default
target has been set.
+Practical configurations may result as a combination of all the
+above scenarios.
.SH ACLs
Note on ACLs: at present you may add whatever ACL rule you desire
to to the Meta (and LDAP) backends.
find other exceptions: <ando@openldap.org>).
The rule
.LP
+.RS
.nf
-
access to dn="<dn>" attr=<attr>
- by dnattr=<dnattr> read
- by * none
+access to dn="<dn>" attr=<attr>
+ by dnattr=<dnattr> read
+ by * none
.fi
+.RE
.LP
cannot be matched iff the attribute that is being requested, <attr>,
is NOT <dnattr>, and the attribute that determines membership,
A string is rewritten according to a set of rules, called a `rewrite
context'.
The rules are based on Regular Expressions (POSIX regex) with
-substring matching; extensions are planned to allow basic variable
-substitution and map resolution of substrings.
+substring matching; basic variable substitution and map resolution
+of substrings is allowed by specific mechanisms detailed in the following.
The behavior of pattern matching/substitution can be altered by a set
of flags.
.LP
for the slapd server (initially dedicated to the LDAP backend).
.SH Passes
An incoming string is matched agains a set of rules.
-Rules are made of a match pattern, a substitution pattern and a set of
-actions.
+Rules are made of a regex match pattern, a substitution pattern
+and a set of actions, described by a set of flags.
In case of match a string rewriting is performed according to the
substitution pattern that allows to refer to substrings matched in the
incoming string.
The actions, if any, are finally performed.
The substitution pattern allows map resolution of substrings.
A map is a generic object that maps a substitution pattern to a value.
+The flags are divided in "Pattern matching Flags" and "Action Flags";
+the former alter the regex match pattern behaviorm while the latter
+alter the action that is taken after substitution.
.SH "Pattern Matching Flags"
.TP
.B `C'
.TP
.B `R'
use POSIX Basic Regular Expressions (default is Extended)
+.TP
+.B `M{n}'
+allow no more than
+.B n
+recursive passes for a specific rule; does not alter the max total count
+of passes, so it can only enforce a stricter limit for a specific rule.
.SH "Action Flags"
.TP
.B `:'
apply the rule once only (default is recursive)
.TP
.B `@'
-stop applying rules in case of match.
+stop applying rules in case of match; the current rule is still applied
+recursively; combine with `:' to apply the current rule only once
+and then stop.
.TP
.B `#'
stop current operation if the rule matches, and issue an `unwilling to
perform' error.
.TP
.B `G{n}'
-jump n rules back and forth (watch for loops!).
+jump
+.B n
+rules back and forth (watch for loops!).
Note that `G{1}' is implicit in every rule.
.TP
.B `I'
ignores errors in rule; this means, in case of error, e.g. issued by a
map, the error is treated as a missed match.
The `unwilling to perform' is not overridden.
-.LP
-The ordering of the flags is significant.
+.TP
+.B `U{n}'
+uses
+.B
+n
+as return code if the rule matches; the flag does not alter the recursive
+behavior of the rule, so, to have it performed only once, it must be used
+in combination with `:', e.g.
+.B `:U{16}'
+returns the value `16' after exactly one execution of the rule, if the
+pattern matches.
+As a consequence, its behavior is equivalent to `@', with the return
+code set to
+.BR n ;
+or, in other words, `@' is equivalent to `U{0}'.
+By convention, the freely available codes are above 16 included;
+the others are reserved.
+.LP
+The ordering of the flags can be significant.
For instance: `IG{2}' means ignore errors and jump two lines ahead
both in case of match and in case of error, while `G{2}I' means ignore
-errors, but jump thwo lines ahead only in case of match.
+errors, but jump two lines ahead only in case of match.
.LP
More flags (mainly Action Flags) will be added as needed.
.SH "Pattern matching:"
See
.BR regex (7).
-.SH "String Substitution:"
-The string substitution happens according to a substitution pattern.
-.TP
-.B -
-substring substitution is allowed with the syntax `\\d' where `d' is a
-digit ranging 0-9 (0 is the full match).
-I see that 0-9 digit expansion is a widely accepted practise; however
-there is no technical reason to use such a strict limit.
-A syntax of the form `\\{ddd}' should be fine if there is any need to
-use a higher number of possible submatches.
-.TP
-.B -
-variable substitution will be allowed (at least when I figure out
-which kind of variable could be proficiently substituted)
-.TP
-.B -
-map lookup will be allowed (map lookup of substring matches in gdbm,
-ldap(!), math(?) and so on maps `a la sendmail'.
-.TP
-.B -
-subroutine invocation will make it possible to rewrite a submatch in
-terms of the output of another rewriteContext.
-.Sh "Old syntax:"
-.TP
-.B `\\' {0-9} [ `{' <name> [ `(' <args> `)' ] `}' ]
-where <name> is the name of a built-in map, and <args> are optional
-arguments to the map, if the map <name> requires them.
-The following experimental maps have been implemented:
-.TP
-.B \\n{xpasswd}
-maps the n-th substring match as uid to the gecos field in
-/etc/passwd;
-.TP
-.B \\n{xfile(/absolute/path)}
-maps the n-th substring match to a `key value' style plain text file.
-.TP
-.B \\n{xldap(ldap://url/with?%0?in?filter)
-maps the n-th substring match to an attribute retrieved by means of an
-LDAP url with substitution of %0 in the filter (NOT IMPL.)
-.SH "New scheme:"
-everything starting with `\\' requires substitution;
+.SH "Substitution Pattern Syntax:"
+Everything starting with `%' requires substitution;
.LP
-the only obvious exception is `\\\\', which is left as is;
+the only obvious exception is `%%', which is left as is;
.LP
-the basic substitution is `\\d', where `d' is a digit;
-0 means the whole string, while 1-9 is a submatch;
+the basic substitution is `%d', where `d' is a digit;
+0 means the whole string, while 1-9 is a submatch, as discussed in
+.BR regex (7);
.LP
-in the outdated schema, the digit may be optionally
-followed by a `{', which means pipe the submatch into
-the map described by the string up to the following `}';
-.LP
-the output of the map is used instead of the submatch;
-.LP
-in the new schema, a `\\' followed by a `{' invokes an
-advanced substitution scheme.
+a `%' followed by a `{' invokes an advanced substitution.
The pattern is:
.LP
-.nf
- `\\' `{' [{ <op> }] <name> `(' <substitution schema> `)' `}'
-.fi
+.RS
+`%' `{' [ <op> ] <name> `(' <substitution> `)' `}'
+.RE
.LP
where <name> must be a legal name for the map, i.e.
.LP
+.RS
.nf
- <name> ::= [a-z][a-z0-9]* (case insensitive)
- <op> ::= `>' `|' `&' `&&' `*' `**' `$'
+<name> ::= [a-z][a-z0-9]* (case insensitive)
+<op> ::= `>' `|' `&' `&&' `*' `**' `$'
.fi
+.RE
.LP
-and <substitution schema> must be a legal substitution
-schema, with no limits on the nesting level.
+and <substitution> must be a legal substitution
+pattern, with no limits on the nesting level.
.LP
The operators are:
.TP
.TP
.B &
variable assignment; <name> defines a variable in the running
-operation structure which can be dereferenced later (NOT IMPL.)
+operation structure which can be dereferenced later; operator
+.B &
+assigns a variable in the rewrite context scope; operator
+.B &&
+assigns a variable that scopes the entire session, e.g. its value
+can be derefenced later by other rewrite contexts
.TP
.B *
variable dereferencing; <name> must refer to a variable that is
-defined and assigned for the running operation (NOT IMPL.)
+defined and assigned for the running operation; operator
+.B *
+dereferences a variable scoping the rewrite context; operator
+.B **
+dereferences a variable scoping the whole session, e.g. the value
+is passed across rewrite contexts
.TP
.B $
parameter dereferencing; <name> must refer to an existing parameter;
the idea is to make some run-time parameters set by the system
-available to the rewrite engine, as the client host name, the bind dn
-if any, constant parameters initialized at config time, and so on (NOT
-IMPL.)
-.LP
-Note: as the slapd parsing routines escape backslashes ('\\'),
-a double backslash is required inside substitution patterns.
-To overcome the resulting heavy notation, the substitution escaping
-has been delegated to the `%' symbol, which should be used
-instead of `\\' in string substitution patterns.
-The symbol can be altered at will by redefining the related macro in
-"rewrite-int.h".
-In the current snapshot, all the `\\' on the left side of each rule
-(the regex pattern) must be converted in `\\\\'; all the `\\' on the
-right side of the rule (the substitution pattern) must be turned into
-`%'.
-In the following examples, the original (more readable) syntax is
-used.
+available to the rewrite engine, as the client host name, the bind DN
+if any, constant parameters initialized at config time, and so on;
+no parameter is currently set by either
+.B back\-ldap
+or
+.BR back\-meta ,
+but constant parameters can be defined in the configuration file
+by using the
+.B rewriteParam
+directive.
+.LP
+Substitution escaping has been delegated to the `%' symbol,
+which is used instead of `\e' in string substitution patterns
+because `\e' is already escaped by slapd's low level parsing routines;
+as a consequence,
+.BR regex (7)
+escaping requires two `\e' symbols, e.g. `\fB.*\e.foo\e.bar\fP' must
+be written as `\fB.*\e\e.foo\e\e.bar\fP'.
+.\"
+.\" The symbol can be altered at will by redefining the related macro in
+.\" "rewrite-int.h".
+.\"
.SH "Rewrite context:"
A rewrite context is a set of rules which are applied in sequence.
The basic idea is to have an application initialize a rewrite
appropriate rewrite context with the input string and obtains the
newly rewritten one if no errors occur.
.LP
-An interesting application, in the LDAP backend or in slapd itself,
-could associate each basic server operation to a rewrite context
-(most of them possibly aliasing the default one).
-Then, DN rewriting could take place at any invocation of a backend
-operation.
+Each basic server operation is associated to a rewrite context;
+they are divided in two main groups: client \-> server and
+server \-> client rewriting.
.LP
client -> server:
.LP
+.RS
.nf
- default if defined and no specific
- context is available
- bindDn bind
- searchBase search
- searchFilter search
- compareDn compare
- addDn add
- modifyDn modify
- modrDn modrdn
- newSuperiorDn modrdn
- deleteDn delete
+(default) if defined and no specific context
+ is available
+bindDN bind
+searchBase search
+searchFilter search
+compareDN compare
+compareAttrDN compare AVA
+addDN add
+addAttrDN add AVA
+modifyDN modify
+modifyAttrDN modify AVA
+modrDN modrdn
+newSuperiorDN modrdn
+deleteDN delete
.fi
+.RE
.LP
server -> client:
.LP
+.RS
.nf
- searchResult search (only if defined; no default)
+searchResult search (only if defined; no default;
+ acts on DN and DN-syntax attributes
+ of search results)
+searchAttrDN search AVA
+matchedDN all ops (only if applicable)
.fi
+.RE
.LP
.SH "Basic configuration syntax"
.TP
rewriting takes place (an easy way to stop rewriting without
altering too much the configuration file).
.TP
-.B rewriteContext <context name> [ alias <aliased context name> ]
+.B rewriteContext <context name> "[ alias <aliased context name> ]"
<Context name> is the name that identifies the context, i.e. the name
used by the application to refer to the set of rules it contains.
It is used also to reference sub contexts in string rewriting.
In this case the alias context contains no rule, and any reference to
it will result in accessing the aliased one.
.TP
-.B rewriteRule <regex pattern> <substitution pattern> [ <flags> ]
-Determines how a tring can be rewritten if a pattern is matched.
+.B rewriteRule "<regex match pattern>" "<substitution pattern>" "[ <flags> ]"
+Determines how a string can be rewritten if a pattern is matched.
Examples are reported below.
.SH "Additional configuration syntax:"
.TP
-.B rewriteMap <map name> <map type> [ <map attrs> ]
+.B rewriteMap "<map name>" "<map type>" "[ <map attrs> ]"
Allows to define a map that transforms substring rewriting into
something else.
The map is referenced inside the substitution pattern of a rule.
.TP
.B rewriteParam <param name> <param value>
Sets a value with global scope, that can be dereferenced by the
-command `\\{$paramName}'.
-.TP
-.B rewriteMaxPasses <number of passes>
-Sets the maximum number of total rewriting passes taht can be
-performed in a signle rewriting operation (to avoid loops).
+command `%{$paramName}'.
+.TP
+.B rewriteMaxPasses <number of passes> [<number of passes per rule>]
+Sets the maximum number of total rewriting passes that can be
+performed in a single rewrite operation (to avoid loops).
+A safe default is set to 100; note that reaching this limit is still
+treated as a success; recursive invocation of rules is simply
+interrupted.
+The count applies to the rewriting operation as a whole, not
+to any single rule; an optional per-rule limit can be set.
+This limit is overridden by setting specific per-rule limits
+with the `M{n}' flag.
.SH "Configuration examples:"
.nf
- # set to `off' to disable rewriting
- rewriteEngine on
+# set to `off' to disable rewriting
+rewriteEngine on
+
+# Everything defined here goes into the `default' context.
+# This rule changes the naming context of anything sent
+# to `dc=home,dc=net' to `dc=OpenLDAP, dc=org'
- # Everything defined here goes into the `default' context.
- # This rule changes the naming context of anything sent
- # to `dc=home,dc=net' to `dc=OpenLDAP, dc=org'
+rewriteRule "(.*)dc=home,[ ]?dc=net"
+ "%1dc=OpenLDAP, dc=org" ":"
- rewriteRule "(.*)dc=home,[ ]?dc=net"
- "\\1dc=OpenLDAP, dc=org" ":"
+# since a pretty/normalized DN does not include spaces
+# after rdn separators, e.g. `,', this rule suffices:
- # Start a new context (ends input of the previous one).
- # This rule adds blancs between dn parts if not present.
- rewriteContext addBlancs
- rewriteRule "(.*),([^ ].*)" "\\1, \\2"
+rewriteRule "(.*)dc=home,dc=net"
+ "%1dc=OpenLDAP,dc=org" ":"
- # This one eats blancs
- rewriteContext eatBlancs
- rewriteRule "(.*),[ ](.*)" "\\1,\\2"
+# Start a new context (ends input of the previous one).
+# This rule adds blanks between DN parts if not present.
+rewriteContext addBlanks
+rewriteRule "(.*),([^ ].*)" "%1, %2"
- # Here control goes back to the default rewrite
- # context; rules are appended to the existing ones.
- # anything that gets here is piped into rule `addBlancs'
- rewriteContext default
- rewriteRule ".*" "\\{>addBlancs(\\0)}" ":"
+# This one eats blanks
+rewriteContext eatBlanks
+rewriteRule "(.*),[ ](.*)" "%1,%2"
- # Anything with `uid=username' is looked up in
- # /etc/passwd for gecos (I know it's nearly useless,
- # but it is there just to test something fancy!). Note
- # the `I' flag that leaves `uid=username' in place if
- # `username' does not have a valid account, and the
- # `:' that forces the rule to be processed exactly once.
- rewriteContext uid2Gecos
- rewriteRule "(.*)uid=([a-z0-9]+),(.+)"
- "\\1cn=\\2{xpasswd},\\3" "I:"
+# Here control goes back to the default rewrite
+# context; rules are appended to the existing ones.
+# anything that gets here is piped into rule `addBlanks'
+rewriteContext default
+rewriteRule ".*" "%{>addBlanks(%0)}" ":"
- # Finally, in a bind, if one uses a `uid=username' dn,
- # it is rewritten in `cn=name surname' if possible.
- rewriteContext bindDn
- rewriteRule ".*" "\\{>addBlancs(\\{>uid2Gecos(\\0)})}" ":"
+.\" # Anything with `uid=username' is looked up in
+.\" # /etc/passwd for gecos (I know it's nearly useless,
+.\" # but it is there just as a guideline to implementing
+.\" # custom maps).
+.\" # Note the `I' flag that leaves `uid=username' in place
+.\" # if `username' does not have a valid account, and the
+.\" # `:' that forces the rule to be processed exactly once.
+.\" rewriteContext uid2Gecos
+.\" rewriteRule "(.*)uid=([a-z0-9]+),(.+)"
+.\" "%1cn=%2{xpasswd},%3" "I:"
+.\"
+.\" # Finally, in a bind, if one uses a `uid=username' DN,
+.\" # it is rewritten in `cn=name surname' if possible.
+.\" rewriteContext bindDn
+.\" rewriteRule ".*" "%{>addBlanks(%{>uid2Gecos(%0)})}" ":"
+.\"
+# Rewrite the search base according to `default' rules.
+rewriteContext searchBase alias default
- # Rewrite the search base according to `default' rules.
- rewriteContext searchBase alias default
+# Search results with OpenLDAP DN are rewritten back with
+# `dc=home,dc=net' naming context, with spaces eaten.
+rewriteContext searchResult
+rewriteRule "(.*[^ ]?)[ ]?dc=OpenLDAP,[ ]?dc=org"
+ "%{>eatBlanks(%1)}dc=home,dc=net" ":"
- # Search results with OpenLDAP dn are rewritten back with
- # `dc=home,dc=net' naming context, with spaces eaten.
- rewriteContext searchResult
- rewriteRule "(.*[^ ]?)[ ]?dc=OpenLDAP,[ ]?dc=org"
- "\\{>eatBlancs(\\1)}dc=home,dc=net" ":"
+# Bind with email instead of full DN: we first need
+# an ldap map that turns attributes into a DN (the
+# argument used when invoking the map is appended to
+# the URI and acts as the filter portion)
+rewriteMap ldap attr2dn "ldap://host/dc=my,dc=org?dn?sub"
- # Bind with email instead of full dn: we first need
- # an ldap map that turns attributes into a dn (the
- # filter is provided by the substitution string):
- rewriteMap ldap attr2dn "ldap://host/dc=my,dc=org?dn?sub"
+# Then we need to detect DN made up of a single email,
+# e.g. `mail=someone@example.com'; note that the rule
+# in case of match stops rewriting; in case of error,
+# it is ignored. In case we are mapping virtual
+# to real naming contexts, we also need to rewrite
+# regular DNs, because the definition of a bindDn
+# rewrite context overrides the default definition.
+rewriteContext bindDn
+rewriteRule "^mail=[^,]+@[^,]+$" "%{attr2dn(%0)}" ":@I"
- # Then we need to detect emails; note that the rule
- # in case of match stops rewriting; in case of error,
- # it is ignored. In case we are mapping virtual
- # to real naming contexts, we also need to rewrite
- # regular DNs, because the definition of a bindDn
- # rewrite context overrides the default definition.
- rewriteContext bindDn
- rewriteRule "(mail=[^,]+@[^,]+)" "\\{attr2dn(\\1)}" "@I"
+# This is a rather sophisticated example. It massages a
+# search filter in case who performs the search has
+# administrative privileges. First we need to keep
+# track of the bind DN of the incoming request, which is
+# stored in a variable called `binddn' with session scope,
+# and left in place to allow regular binding:
+rewriteContext bindDn
+rewriteRule ".+" "%{&&binddn(%0)}%0" ":"
- # This is a rather sophisticate example. It massages a
- # search filter in case who performs the search has
- # administrative privileges. First we need to keep
- # track of the bind dn of the incoming request:
- rewriteContext bindDn
- rewriteRule ".+" "\\{**&binddn(\\0)}" ":"
+# A search filter containing `uid=' is rewritten only
+# if an appropriate DN is bound.
+# To do this, in the first rule the bound DN is
+# dereferenced, while the filter is decomposed in a
+# prefix, in the value of the `uid=<arg>' AVA, and
+# in a suffix. A tag `<>' is appended to the DN.
+# If the DN refers to an entry in the `ou=admin' subtree,
+# the filter is rewritten OR-ing the `uid=<arg>' with
+# `cn=<arg>'; otherwise it is left as is. This could be
+# useful, for instance, to allow apache's auth_ldap-1.4
+# module to authenticate users with both `uid' and
+# `cn', but only if the request comes from a possible
+# `cn=Web auth,ou=admin,dc=home,dc=net' user.
+rewriteContext searchFilter
+rewriteRule "(.*\e\e()uid=([a-z0-9_]+)(\e\e).*)"
+ "%{**binddn}<>%{&prefix(%1)}%{&arg(%2)}%{&suffix(%3)}"
+ ":I"
+rewriteRule "[^,]+,ou=admin,dc=home,dc=net"
+ "%{*prefix}|(uid=%{*arg})(cn=%{*arg})%{*suffix}" ":@I"
+rewriteRule ".*<>" "%{*prefix}uid=%{*arg}%{*suffix}" ":"
- # A search filter containing `uid=' is rewritten only
- # if an appropriate dn is bound.
- # To do this, in the first rule the bound dn is
- # dereferenced, while the filter is decomposed in a
- # prefix, the argument of the `uid=', and in a
- # suffix. A tag `<>' is appended to the DN. If the DN
- # refers to an entry in the `ou=admin' subtree, the
- # filter is rewritten OR-ing the `uid=<arg>' with
- # `cn=<arg>'; otherwise it is left as is. This could be
- # useful, for instance, to allow apache's auth_ldap-1.4
- # module to authenticate users with both `uid' and
- # `cn', but only if the request comes from a possible
- # `dn: cn=Web auth, ou=admin, dc=home, dc=net' user.
- rewriteContext searchFilter
- rewriteRule "(.*\\()uid=([a-z0-9_]+)(\\).*)"
- "\\{**binddn}<>\\{&prefix(\\1)}\\{&arg(\\2)}\\{&suffix(\\3)}"
- ":I"
- rewriteRule "[^,]+,[ ]?ou=admin,[ ]?dc=home,[ ]?dc=net"
- "\\{*prefix}|(uid=\\{*arg})(cn=\\{*arg})\\{*suffix}" "@I"
- rewriteRule ".*<>" "\\{*prefix}uid=\\{*arg}\\{*suffix}"
+# This example shows how to strip unwanted DN-valued
+# attribute values from a search result; the first rule
+# matches DN values below "ou=People,dc=example,dc=com";
+# in case of match the rewriting exits successfully.
+# The second rule matches everything else and causes
+# the value to be rejected.
+rewriteContext searchResult
+rewriteRule ".*,ou=People,dc=example,dc=com" "%0" ":@"
+rewriteRule ".*" "" "#"
.fi
-.SH "LDAP Proxy resolution (a possible evolution of slapd-ldap(5):"
-In case the rewritten dn is an LDAP URL, the operation is initiated
-towards the host[:port] indicated in the url, if it does not refer
+.SH "LDAP Proxy resolution (a possible evolution of slapd\-ldap(5)):"
+In case the rewritten DN is an LDAP URI, the operation is initiated
+towards the host[:port] indicated in the uri, if it does not refer
to the local server.
E.g.:
.LP
.nf
- rewriteRule \'^cn=root,.*\' \'\\0\' \'G{3}\'
- rewriteRule \'^cn=[a-l].*\' \'ldap://ldap1.my.org/\\0\' \'@\'
- rewriteRule \'^cn=[m-z].*\' \'ldap://ldap2.my.org/\\0\' \'@\'
- rewriteRule \'.*\' \'ldap://ldap3.my.org/\\0\' \'@\'
+ rewriteRule '^cn=root,.*' '%0' 'G{3}'
+ rewriteRule '^cn=[a-l].*' 'ldap://ldap1.my.org/%0' ':@'
+ rewriteRule '^cn=[m-z].*' 'ldap://ldap2.my.org/%0' ':@'
+ rewriteRule '.*' 'ldap://ldap3.my.org/%0' ':@'
.fi
.LP
(Rule 1 is simply there to illustrate the `G{n}' action; it could have
been written:
.LP
.nf
- rewriteRule \'^cn=root,.*\' \'ldap://ldap3.my.org/\\0\' \'@\'
+ rewriteRule '^cn=root,.*' 'ldap://ldap3.my.org/%0' ':@'
.fi
.LP
with the advantage of saving one rewrite pass ...)
-.SH "SEE ALSO"
+.SH PROXY CACHE OVERLAY
+The proxy cache overlay
+allows caching of LDAP search requests (queries) in a local database.
+For an incoming query, the
+proxy cache determines its corresponding \fBtemplate\fP. If the template was
+specified as cacheable using the \fBproxytemplate\fP directive and the request is
+contained in a cached request, it is answered from the proxy cache. Otherwise,
+the search is performed as usual and cacheable search results are saved in the
+cache for use in future queries.
+.LP
+
+A template is defined by a filter string and an index identifying a set of
+attributes. The \fBtemplate string\fP for a query can be obtained by
+removing assertion values from the RFC 2254 representation of its search
+filter. A query belongs to a template if its template string and set of
+projected attributes correspond to a cacheable template. Examples of template strings are (mail=), (|(sn=)(cn=)), (&(sn=)(givenName=)).
+
+.LP
+The following cache specific directives can be used to configure the proxy
+cache:
+.TP
+.B overlay proxycache
+This directive adds the proxycache overlay to the current backend. The
+proxycache overlay may be used with any backend but is intended for use
+with the
+.B ldap
+and
+.B meta
+backends.
+.TP
+.B proxycache <database> <max_entries> <numattrsets> <entry_limit> <cc_period>
+The directive enables proxy caching in the current backend and sets general
+cache parameters. A <database> backend will be used internally to maintain
+the cached entries. The chosen database will need to be configured as well,
+as shown below. Cache replacement is invoked when the cache size grows to
+<max_entries> entries and continues till the cache size drops below this size.
+<numattrsets> should be equal to the number of following \fBproxyattrset\fP
+directives. Queries are cached only if they correspond to a cacheable template
+(specified by the \fBproxytemplate\fP directive) and the number of entries
+returned is less than <entry_limit>. Consistency check is performed every
+<cc_period> duration (specified in secs). In each cycle queries with expired
+"time to live(\fBTTL\fP)" are removed. A sample cache configuration is:
+.LP
+.RS
+proxycache \fBbdb 10000 1 50 100\fP
+.RE
+.TP
+.B proxyattrset <index> <attrs...>
+Used to associate a set of attributes <attrs..> with an <index>. Each attribute
+set is associated with an integer from 0 to <numattrsets>-1. These indices are
+used by the \fBproxytemplate\fP directive to define cacheable templates.
+
+.TP
+.B proxytemplate <template_string> <attrset_index> <ttl>
+Specifies a cacheable template and "time to live" (in sec) <ttl> of queries
+belonging to the template.
+
+.LP
+The following adds a template with filter string (&sn=)(givenName=)) and attributes mail, postaladdress, telephonenumber and a TTL of 1 hour.
+.LP
+.RS
+.nf
+proxyattrset \fB0 mail postaladdress telephonenumber\fP
+proxytemplate \fB(&(sn=)(givenName=)) 0 3600\fP
+.fi
+.RE
+.LP
+Directives for configuring the underlying database must also be given, as
+shown here:
+.LP
+.RS
+.nf
+directory /var/tmp/cache
+cachesize 100
+.fi
+.RE
+.LP
+Any valid directives for the chosen database type may be used.
+.SH FILES
+.TP
+ETCDIR/slapd.conf
+default slapd configuration file
+.SH SEE ALSO
.BR slapd.conf (5),
+.BR slapd\-ldap (5),
.BR slapd (8),
.BR regex (7).
+.SH AUTHOR
+Pierangelo Masarati, based on back-ldap by Howard Chu
projects / openldap / blobdiff