sss_sifp: set output parameters if attribute is NULL There are two cases that may happen when a user calls Get or GetAll: 1) the attribute is missing 2) the attribute is empty sss_sifp has two error code to distinguish between those two cases: 1) SSS_SIFP_ATTR_MISSING 2) SSS_SIFP_ATTR_NULL Usually the caller is not interested on situations when the attribute is empty and it can be considered as error. Having it as a separate error code instead of setting the output value to NULL is necesarry since attribute does not have to be a pointer. This patch however sets pointer type attributes to NULL since it may simplify the code path when the caller is actually interested in this information (e. g. empty server list on domain objects). It is not possible to send a NULL string over a D-Bus nor it is possible to have hash table NULL with current code so these two scenarios are not tested. However, it is handled in sss_sifp_attr code for completeness. Reviewed-by: Lukáš Slebodník <lslebodn@redhat.com>

sss_sifp: add support for string dictionary https://fedorahosted.org/sssd/ticket/2254 Reviewed-by: Sumit Bose <sbose@redhat.com>

sss_sifp: implement API https://fedorahosted.org/sssd/ticket/2254 Reviewed-by: Sumit Bose <sbose@redhat.com>