SO_PASSCRED and SCM_CREDENTIALS | error: use of undeclared identifier

Hi

Disclaimer:

I am trying to create a new port (knot-resolver-current) developed under Linux upstream. A so-called manager functionality is brand new in comparison to the previous knot-resolver. The corresponding git repository is leading edge development.

My main motivation is: learning how to create ports ;-)


Compilation fails:

cc -pthread -Wno-unused-result -Wsign-compare -Wunreachable-code -DNDEBUG -O2 -pipe -fstack-protector-strong -fno-strict-aliasing -fPIC -I/usr/local/include/python3.9 -c knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.c -o build/temp.freebsd-14.0-STABLE-amd64-cpython-39/knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.o
knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.c:52:42: error: use of undeclared identifier 'SO_PASSCRED'
   52 |         res = setsockopt(controlfd, SOL_SOCKET, SO_PASSCRED, &data,
      |                                                 ^
knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.c:97:23: error: invalid application of 'sizeof' to an incomplete type 'struct ucred'
   97 |         char cmsg[CMSG_SPACE(sizeof(struct ucred))];
      |                              ^     ~~~~~~~~~~~~~~
/usr/include/sys/socket.h:577:65: note: expanded from macro 'CMSG_SPACE'
  577 | #define CMSG_SPACE(l)           (_ALIGN(sizeof(struct cmsghdr)) + _ALIGN(l))
      |                                                                          ^
/usr/include/x86/_align.h:51:35: note: expanded from macro '_ALIGN'
   51 | #define _ALIGN(p)       (((__uintptr_t)(p) + _ALIGNBYTES) & ~_ALIGNBYTES)
      |                                         ^
knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.c:97:37: note: forward declaration of 'struct ucred'
   97 |         char cmsg[CMSG_SPACE(sizeof(struct ucred))];
      |                                            ^
knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.c:116:27: error: use of undeclared identifier 'SCM_CREDENTIALS'
  116 |                 if (cmsgp->cmsg_type == SCM_CREDENTIALS) {
      |                                         ^
knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.c:118:36: error: invalid application of 'sizeof' to an incomplete type 'struct ucred'
  118 |                         cmsgp->cmsg_len != CMSG_LEN(sizeof(struct ucred)) ||
      |                                                     ^     ~~~~~~~~~~~~~~
/usr/include/sys/socket.h:578:57: note: expanded from macro 'CMSG_LEN'
  578 | #define CMSG_LEN(l)             (_ALIGN(sizeof(struct cmsghdr)) + (l))
      |                                                                    ^
knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.c:97:37: note: forward declaration of 'struct ucred'
   97 |         char cmsg[CMSG_SPACE(sizeof(struct ucred))];
      |                                            ^
knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.c:125:17: error: variable has incomplete type 'struct ucred'
  125 |                         struct ucred cred;
      |                                      ^
knot_resolver_manager/kresd_controller/supervisord/plugin/notifymodule.c:97:37: note: forward declaration of 'struct ucred'
   97 |         char cmsg[CMSG_SPACE(sizeof(struct ucred))];
      |                                            ^
5 errors generated.
error: command '/usr/bin/cc' failed with exit code 1
FAILED: install script '/bin/bash /wrkdirs/usr/ports/dns/knot-resolver-current/work/knot-resolver-v6.0.6/manager/scripts/install.sh /usr/local/bin/python3' failed with exit code 1.


Both SO_PASSCRED and SCM_CREDENTIALS aren't defined in the complete git repository.


Is there a way to include Linux compatibility regarding sockets? 


Thanks and regards,
Michael