Fix for Bug#52923 (Inadequate documentation of "Can't get hostname for your address" error).

The thing is that on some platforms (e.g. Mac OS X) sockaddr_in / sockaddr_in6
contain a non-standard field (sin_len / sin6_len), that must be set.

The problem was that only standard fields were set, thus getnameinfo() returned
EAI_SYSTEM instead of EAI_NONAME.

The fix is to introduce configure-time checks (for GNU auto-tools and CMake) for
those additional fields and to set them if they are available.

1 files changed, 11 insertions, 3 deletions

diff --git a/vio/viosocket.c b/vio/viosocket.c
index 6c361e4a462..9c0243db4f3 100644
--- a/vio/viosocket.c
+++ b/vio/viosocket.c
@@ -1057,9 +1057,11 @@ ssize_t vio_pending(Vio *vio)
 
 /**
   This is a wrapper for the system getnameinfo(), because different OS
-  differ in the getnameinfo() implementation. For instance, Solaris 10
-  requires that the 2nd argument (salen) must match the actual size of the
-  struct sockaddr_storage passed to it.
+  differ in the getnameinfo() implementation:
+    - Solaris 10 requires that the 2nd argument (salen) must match the
+      actual size of the struct sockaddr_storage passed to it;
+    - Mac OS X has sockaddr_in::sin_len and sockaddr_in6::sin6_len and
+      requires them to be filled.
 */
 
 int vio_getnameinfo(const struct sockaddr *sa,
@@ -1072,11 +1074,17 @@ int vio_getnameinfo(const struct sockaddr *sa,
   switch (sa->sa_family) {
   case AF_INET:
     sa_length= sizeof (struct sockaddr_in);
+#ifdef HAVE_SOCKADDR_IN_SIN_LEN
+    ((struct sockaddr_in *) sa)->sin_len= sa_length;
+#endif /* HAVE_SOCKADDR_IN_SIN_LEN */
     break;
 
 #ifdef HAVE_IPV6
   case AF_INET6:
     sa_length= sizeof (struct sockaddr_in6);
+# ifdef HAVE_SOCKADDR_IN6_SIN6_LEN
+    ((struct sockaddr_in6 *) sa)->sin6_len= sa_length;
+# endif /* HAVE_SOCKADDR_IN6_SIN6_LEN */
     break;
 #endif /* HAVE_IPV6 */
   }