The glibc docs explain nsswitch well. https://www.gnu.org/software/libc/manual/html_node/Name-Service-Switch.html https://www.gnu.org/software/libc/manual/html

The glibc docs explain nsswitch well. https://www.gnu.org/software/libc/manual/html_node/Name-Service-Switch.html https://www.gnu.org/software/libc/manual/html_node/Name-Serv... https://www.gnu.org/software/libc/manual/html_node/Adding-another-Service-to-NSS.html https://www.gnu.org/software/libc/manual/html_node/Adding-an... in particular, which explains how to write a custom NSS service as a shared library. I expect the concern the article raises applies to all custom NSS services, such as: - sssd: https://ubuntu.com/server/docs/service-sssd-ad https://ubuntu.com/server/docs/service-sssd-ad - nsscache: https://github.com/google/nsscache https://github.com/google/nsscache