NAME

       dh_installnss - enable NSS services

SYNOPSIS

       dh_installnss [debhelper options]

DESCRIPTION

       dh_installnss is a debhelper program that is responsible for injecting NSS (Name Service
       Switch) services into /etc/nsswitch.conf.

FILES

       debian/package.nss
           Lists the services to inject into /etc/nsswitch.conf when a package is configured and
           to remove when a package is removed or purged.

           Each line in that file (a directive) should be of the form

           db position service action condition

           where the fields contain the following pieces of information:

           db  The NSS database in which the service will be added.  Usually "hosts".

           position
               Where to add the NSS service.

               Possible values are "first", "last", "before=service", "after=service", plus the
               pseudo-positions "remove-only", "database-add" and "database-require".

               The pseudo-position "remove-only" is used to mark services that are not going to
               be added during the installation of the package, but that will be removed during
               its deinstallation (e.g., legacy services).

               The pseudo-position "database-add" is used to request the addition of a non-
               standard NSS database to /etc/nsswitch.conf during the installation of the package
               and its removal during the deinstallation of the package.  When "database-add" is
               used, all other fields in the directive should be left empty.

               The pseudo-position "database-require" is used to announce that one or more
               services in the nss file will be installed under a non-standard NSS database added
               by another package.  When "database-require" is used, all other fields in the
               directive should be left empty.

           service
               The name of the NSS service to add.

           action
               Optional action specification "[STATE=ACTION]".

           condition
               Optional set of conditions to better define when a service should (or should not)
               be installed.

               Only one kind of condition is currently defined:
               "skip-if-present=service,service,...".

           Additionally, text between a "#" character and the end of line is ignored.

EXAMPLES

       An example debian/nss file could look like this:

           hosts before=dns mdns4
           hosts before=mdns4 mdns4_minimal [NOTFOUND=return]
           hosts remove-only mdns    # In case the user manually added it

       After the installation of this package, the original configuration of the hosts database
       in /etc/nsswitch.conf will change from:

           hosts:    files dns

       to:

           hosts:    files mdns4_minimal [NOTFOUND=return] mdns4 dns

CAVEATS

   Non-standard NSS databases
       Directives in a package.nss file can reference a non-standard NSS database only if that
       database has been first declared with a "database-add" or "database-require" directive in
       the same file.

       Non-standard NSS databases are all databases that are not defined in /etc/nsswitch.conf as
       shipped by the package base-files.

       If a directive references an undeclared non-standard NSS database (e.g., "somedb"),
       dh_installnss will exit with the error message "Unknown NSS database 'somedb'".

       A non-standard NSS database can be declared by at most one installed package.  In other
       words, if the directives in the nss files of two packages A and B reference the same non-
       standard NSS database "somedb" and both packages can be installed at the same time, one of
       the following two solutions must be implemented:

       1.  Package A supplies the "somedb database-add" directive, package B Pre-Depends on A and
           uses a "somedb database-require" directive.

       2.  The shared package C supplies the "somedb database-add" directive, both package A and
           B Pre-Depend on C and use a "somedb database-require" directive.

SEE ALSO

       debhelper(7)

       This program is a debhelper addon.

AUTHOR

       Gioele Barabucci <gioele@svario.it>