INTERNET-DRAFT Leif Johansson
Intented Category: Experimental Stockholm University
A directory (X.500 and LDAPv3) schema for Berkely automounter
1. Status of this Memo
This memo describes a directory (LDAP or X.500) schema for storing amd (Berkely-
style automounter) mount info maps. The schema is currently beeing supported by
the (beta version of the) am-utils version 6 package [AMUTILS].
2. Overview and Rationale
Directory services such as X.500 [X500] or LDAP [RFC2251] are a natural choice of
repository for amd mount map databases. All Object Identifiers in this document
are prefixed by amdSchema-id to be assigned later. The relation between this
schema and the automount schema elements in [HOWARD] are mostly superficial. The
model for the elements in [HOWARD] was the SUN automounter which has quite a
different syntax for mount maps. Furthermore the intended usage of this schema
differs from that of [HOWARD] in many respects.
3. DSA requirements
Directory servers implementing this schema SHOULD maintain the modifyTimestamp
operational attribute. If not the amdMapCacheTtl attribute SHOULD be set to 0
indicating to clients that caching of map entries SHOULD be turned off. Clients
wishing to use the amdMap schema MAY use the modifyTimestamp information to set
the ttl for internal caching schemes. A value of 0 for the amdMapCacheTtl must
result in clients turning off any local caching.
4. Syntax definitions
The following attribute syntax is defined in this document:
amdlocationlist
This syntax represents a amd map value. This is the syntax expressed in BNF using
definitions from [RFC2252]:
amdlocationlist = amdlocationselection |
amdlocationlist whsp "||" whsp amdlocationselection
amdlocationselection = amdlocation |
amdlocationselection whsp amdlocation
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amdlocation = amdlocationinfo |
"-" amdlocationinfo |
"-"
amdlocationinfo = seloropt |
amdlocationinfo ";" seloropt |
";"
seloropt = seletion |
optass
selection = keystring "==" printablestring
keystring "!=" printablestring
optass = keystring
X.500 servers or LDAPv3 servers (supporting the binary attribute option) may use
the following syntax definition:
AmdLocationList ::= SEQUENCE OF {
SEQUENCE OF {
location AmdLocation
}
}
AmdLocation ::= SET OF {
CHOICE {
location [0] AmdLocationInfo
notlocation [1] AmdLocationInfo
not [2] NULL
}
}
AmdLocationInfo ::= SET OF {
CHOICE {
selection [0] AmdSelection
option [1] AmdOption
}
}
AmdSelection ::= CHOICE {
eq [0] AttributeAndValue
ne [1] AttributeAndValue
}
AmdOption ::= AttributeAndValue
AttributeAndValue ::= SEQUENCE {
attribute IA5String
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value IA5String
}
5. Attribute types
The following attribute types are defined in this document:
amdMapName
amdMapCacheTtl
amdMapEntry
amdMapEntryKey
amdMapEntryValue
amdSchema-a OBJECT IDENTIFIER ::= { amdSchema-id 1 }
amdMapName ATTRIBUTE ::= {
WITH SYNTAX IA5String
EQUALITY MATCHING RULE caseIgoreExactMatch
--ID { amdSchema-a 1 }
DESCRIPTION
"This attribute is the symbolic and in the naming
context unique name of an amd map. This corresponds
in the case of a flat file database to the name of
the file or the mount-point of the map."
}
amdMapCacheTtl
ATTRIBUTE ::= {
WITH SYNTAX Integer
EQUALITY MATCHING RULE integerExactMatch
--ID { amdSchema-a 2 }
SINGLE VALUED
DESCRIPTION
"The maximum time-to-live for the entries in this
map. After this many milliseconds the map has to
be cleared from local caches and reloaded. A value
of 0 disables caching."
}
amdMapEntry
ATTRIBUTE ::= {
WITH SYNTAX DistinguishedName
EQUALITY MATHCING RULE dNCaseIgnoreExactMatch
--ID { amdSchema-a 3 }
DESCRIPTION
"A multivalued attribute listing the distinguished
names of the amdMapEntries making up this amdMap
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object."
}
amdMapEntryKey ::= {
ATTRIBUTE ::= {
WITH SYNTAX IA5String
EQUALITY MATCHING RULE stringExactMatch
--ID { amdSchema-a 4 }
SINGLE VALUED
DESCRIPTION
"The value of this attribute is usually the name of
a mountpoint for this amdMapEntry."
}
amdMapEntryValue ::= {
ATTRIBUTE ::= {
WITH SYNTAX AmdLocationList
--ID { amdSchema-a 5 }
DESCRIPTION
"This is the actual mount information for the amdMapEntry
using the syntax described above."
}
amdMapEntryKey ::= {
ATTRIBUTE ::= {
WITH SYNTAX IA5String
EQUALITY MATCHING RULE stringExactMatch
--ID { amdSchema-a 4 }
SINGLE VALUED
DESCRIPTION
"The value of this attribute is usually the name of
a mountpoint for this amdMapEntry."
}
amdMapEntryValue ::= {
ATTRIBUTE ::= {
WITH SYNTAX AmdLocationList
--ID { amdSchema-a 5 }
DESCRIPTION
"This is the actual mount information for the amdMapEntry
using the syntax described above."
}
6. Object classes
The following object classes are defined in this document:
amdMap
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amdMapEntry
defined as follows:
amdSchema-oc ::= { amdSchema-id 2 }
amdMap OBJECT-CLASS ::= {
SUBCLASS OF { top }
KIND auxiliary
--ID { amdSchema-oc 1 }
MAY CONTAIN { amdMapCacheTtl , cn }
MUST CONTAIN { amdMapName , amdMapEntry }
}
amdMapEntry OBJECT-CLASS ::= {
SUBCLASS OF { top }
KIND structural
--ID { amdSchema-oc 2 }
MUST CONTAIN {
amdMapName ,
amdEntryKey ,
amdEntryValue ,
} MAY CONTAIN
{ cn } DESCRIPTION "An entry of this
object class describes mount information relative to a
certain amdMap entry"
}
7. Examples
8. Security Considerations
Due to the security problems posed by NFS care should be taken not to advertise
exported filesystems. Therefore it is often desirable to limit access to entries
carrying amd mount map information to those systems to which the corresponding
filesystems have been exported.
9. References
[AMUTILS]
am-utils homepage: http://shekel.cs.columbia.edu/~erez/am-utils.html
[RFC2251]
M. Wahl, T. Howes, S. Kille, "Lightweight Directory Access
Protocol (v3)", RFC 2251, December 1997.
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[RFC2252]
M. Wahl, A. Coulbeck, T. Howes, S. Kille, "Lightweight Directory
Access Protocol (v3): Attribute Syntax Definitions", RFC 2252,
December 1997.
[RFC2253]
M. Wahl, S. Kille, T. Howes, "Lightweight Directory Access
Protocol (v3): UTF-8 String Representation of Distinguished
Names", RFC 2253, December 1997.
[HOWARD]
Luke Howard, "An Approach for Using LDAP as a Network
Information Service", draft-howard-nis-schema-??.txt, Internet
draft.
[X500]
ITU something or other.
Author's Address
Leif Johansson
Department of Mathematics
Stockholm University
S-106 91 Stockholm
SWEDEN
Email: leifj AT matematik.su.se
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