libval_shim(3)                Programmer's Manual               libval_shim(3)

                             The Validator Shim Library

       The validator shim library ( is a shared library
       designed to be dynamically loaded using the 'LD_PRELOAD' mechanism
       ( supported on linux and various other unix-like platforms.
       The shim library implements wrappers for a number of DNS related
       functions and in turn calls equivalent DNSSEC-aware validating
       functions from libval(3), mapping the results to return codes
       recognized by the original functions. In this way a wide variety of
       applications can be made DNSSEC aware without code changes and

       The method of mapping return codes assumes that any 'untrusted' or
       failure result from the libval(3) function is reflected as a failure to
       the original calling function.

       To load the library set LD_PRELOAD variable within the environment of
       the the target application prior to execution:

   Validation Policy:
       The validator shim library will create a policy context and cache it
       for all subsequent libval(3) calls. A NULL policy label will be passed
       to create the context. The policy is chosen according to rules defined
       for libval(3).

       See dnsval.conf(1) for information on policy labels and definition.

       Logging for the libval(3) functions may be enabled in the shim library
       by setting an environment variable.

       See dt-validate(1) for specifics.

   setuid/setgid programs
       setuid and setgid root programs (e.g., ping(8)) do not honor the
       LD_PRELOAD setting. These application may still use the LD_PRELOAD
       mechanism when run directly from a root shell.

       Copyright 2004-2013 SPARTA, Inc.  All rights reserved.  See the COPYING
       file included with the dnssec-tools package for details.

       G. S. Marzot

       libsres(3), libval(3), dnsval.conf(1), gethostbyname(3)

       gethostbyaddr(3), getnameinfo(3), getaddrinfo(3), res_query(3)

perl v5.18.4                      2015-04-27                    libval_shim(3)