above the home dir which is only group acessable:
directroy owner group permission
/a root wheel 755
/a/b root b 750 <
/a/b/c c b 700
/a/b/c/.rhosts c b 600
add getegid and initgroups before and setegid behind fopen to fix this.
add <netgroup.h> for the prototype of innetgr.