Provided by: dacs_1.4.40-2_amd64 bug


       dacs.vfs - the DACS virtual filestore


       These files are part of the DACS suite.

       The virtual filestore provides flexible ways for DACS and software built on top of DACS to
       obtain information regardless of how or where the information is stored. The DACS core
       accesses (almost) all configuration information through the virtual filestore layer,
       allowing information to be more easily shared and maintained, secured, or organized for
       better performance.

       Sometimes it is easiest to store information in a regular file initially, where it can be
       modified using an ordinary text editor, but after some growth a database might improve
       performance. In some situations, accessing the information remotely, via HTTP, makes
       administration more convenient or is more secure. A goal of the virtual filestore is to
       make data storage alternatives easier to specify and change.

   The vfs_uri and Item Types
       Many DACS components need to access data to perform their function. The documentation for
       a component will specify a reserved, case-sensitive name called an item type for each data
       set that it may use. For example, dacspasswd(1)[1] identifies the account information that
       it manages by the name passwds.

       Item types start with an alphabetic character followed by zero or more alphanumerics,
       hyphens, and underscores. Item types used by DACS are always completely lower case. Some
       other item types used by DACS are federation_keys and jurisdiction_keys (used by
       dacskey(1)[2] and others), and revocations (used by dacs.acls(5)[3] and others). The
       dacsconf(1)[4] command can list all reserved item types.

       The VFS[5] directive is used to specify the mapping from an item type to a vfs_uri, which
       describes where and how the information is stored. Some commands and functions take a
       vfs_uri as an argument to provide a default or override a default. A vfs_uri has the
       following syntax:

           vfs_uri -> [ '[' item_type ']' ] URI

       The general form of the URI syntax is (see RFC 2396[6] and RFC 3986[7]):

           scheme : [ // authority] [path] [query] [fragment]

       The distribution's conf/site.conf-std file (by default installed as
       /usr/local/dacs/federations/site.conf; see dacs.install(7)[8]) specifies defaults for many
       item types. For example, it defines the "roles file" (item type roles; see
       dacs_authenticate(8)[9]) as:

           VFS "[roles]dacs-kwv-fs:${Conf::FEDERATIONS_ROOT}/${Conf::FEDERATION_DOMAIN}/${Conf::JURISDICTION_NAME}/roles"

       For the hypothetical federation domain and jurisdiction J1, by default this
       would resolve to a file, /usr/local/dacs/federations/ That file might
       consist of entries like:


       The default location of the DACS XML DTDs (item type dtds) is defined as:

           VFS "[dtds]dacs-fs:${Conf::DACS_HOME}/www/dtd-xsd"

       By default, this would resolve to the directory /usr/local/dacs/www/dtd-xsd.

       Refer to the VFS[5] directive for additional detail.

   Virtual Filestore Details
       Each virtual filestore instance contains either an uninterpreted sequence of bytes (e.g.,
       a Unix file or the output of a program) or an object that contains zero or more items,
       each of which is associated with a key (i.e., the name of an item relative in its virtual
       filestore context) and has an uninterpreted sequence of bytes as its value (e.g., a
       database file, a Unix file containing lines having a particular keyword/value structure,
       or a directory containing regular files).

       For maximum portability, a key should be composed of characters from the Portable Filename
       Character Set[10]: any alphanumeric character, period, hyphen, or underscore. The true
       limitation on the character set depends on the underlying storage scheme and URI syntax
       constraints. There is no a priori limit on naming context or key length.


       dacsvfs(1)[11], dacs.conf(5)[12], dacs.install(7)[8], dacs_vfs(8)[13]


       Distributed Systems Software ([14])


       Copyright © 2003-2015 Distributed Systems Software. See the LICENSE[15] file that
       accompanies the distribution for licensing information.


        1. dacspasswd(1)

        2. dacskey(1)

        3. dacs.acls(5)

        4. dacsconf(1)

        5. VFS

        6. RFC 2396

        7. RFC 3986

        8. dacs.install(7)

        9. dacs_authenticate(8)

       10. Portable Filename Character Set

       11. dacsvfs(1)

       12. dacs.conf(5)

       13. dacs_vfs(8)


       15. LICENSE