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>

perl v5.36.0                                       2022-11-01                                   DH_INSTALLNSS(1)