I've no idea how SELinux works, so I'm not up to testing any of what I'm saying here myself, but some notes follow anyway. Please clarify:
On system protected by SELinux, when an application with active LDAP connection tries to exec() binary with different security context, SELinux inspects all opened filedescriptors, including the ldap one, and denies access to the ones, which do not conform active policy (the executed binary is not authorized to contact LDAP servers). Users are then annoyed by security warnings in the logs.
More to the point, some of those security warnings may indicate real security problems. Bind with password, exec some application, and then that application has the bound user's access to LDAP.
The message could be indicating a bug in the app - that it should release its resources (such as descriptors) before exec(). Except, I presume this happens in system() as well? I'd be unfortunate if LDAP apps could not use system() safely.
+#ifdef _GNU_SOURCE
fcntl(s, F_SETFD, FD_CLOEXEC);+#endif
_GNU_SOURCE depends on the compiler flags. Please try #ifdef FD_CLOEXEC instead.
Also I expect the same should be done in os-local.c:ldap_pvt_socket(), which opens ldapi:// sockets. Can you check if the same problem occurs if you run slapd ... -h ldapi:// and a client which listens to that URL instead of ldap:// ? ldapi:// creates a unix-domain socket file somehwere, typically /usr/local/var/run/ldapi If you want to use some other filename you can use ldapi://<URL-escaped filename>/ e.g. ldapi://%2Fhome%2Fjsafrane%2Fldapi/