Unix GSSAPI: support static linking against Heimdal.

Heimdal provides its own definitions of OIDs like GSS_C_NT_USER_NAME
in the form of macros, which conflict with our attempt to redefine
them as variables - the macro gets expanded into the middle of the
variable declaration, leaving the poor C compiler trying to parse a
non-declaration along the lines of

const_gss_OID (&__gss_c_nt_anonymous_oid_desc) = oids+5;

Easily fixed by just not redefining these at all if they're already
defined as macros. To make that easier, I've broken up the oids[]
array into individual gss_OID_desc declarations, so I can put each one
inside the appropriate ifdef.

In the process, I've removed the 'const' from the gss_OID_desc
declarations. That's on purpose! The problem is that not all
implementations of the GSSAPI headers make const_gss_OID a pointer to
a *const* gss_OID_desc; sometimes it's just a plain one and the
'const' prefix is just a comment to the user. So removing that const
prevents compiler warnings (or worse) about address-taking a const
thing and assigning it into a non-const pointer.

ssh/pgssapi.c

@@ -9,38 +9,63 @@
 
 #ifndef NO_LIBDL
 
-/* Reserved static storage for GSS_oids.  Comments are quotes from RFC 2744. */
+/* Reserved static storage for GSS_oids.
-static const gss_OID_desc oids[] = {
+ * Constants of the form GSS_C_NT_* are specified by rfc 2744.
+ * Comments are quotes from RFC 2744 itself.
+ *
+ * These may be #defined to complex expressions by the local header
+ * file, if we're including one in static-GSSAPI mode. (For example,
+ * Heimdal defines them to things like
+ * (&__gss_c_nt_user_name_oid_desc).) So we only define them if
+ * needed. */
+
+#ifndef GSS_C_NT_USER_NAME
+static gss_OID_desc oid_GSS_C_NT_USER_NAME = {
     /* The implementation must reserve static storage for a
      * gss_OID_desc object containing the value */
-    {10, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x01"},
+    10, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x01",
     /* corresponding to an object-identifier value of
      * {iso(1) member-body(2) United States(840) mit(113554)
      * infosys(1) gssapi(2) generic(1) user_name(1)}.  The constant
      * GSS_C_NT_USER_NAME should be initialized to point
-     * to that gss_OID_desc.
+     * to that gss_OID_desc. */
+};
+const_gss_OID GSS_C_NT_USER_NAME = &oid_GSS_C_NT_USER_NAME;
+#endif
 
-     * The implementation must reserve static storage for a
+#ifndef GSS_C_NT_MACHINE_UID_NAME
+static gss_OID_desc oid_GSS_C_NT_MACHINE_UID_NAME = {
+    /* The implementation must reserve static storage for a
      * gss_OID_desc object containing the value */
-    {10, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x02"},
+    10, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x02",
     /* corresponding to an object-identifier value of
      * {iso(1) member-body(2) United States(840) mit(113554)
      * infosys(1) gssapi(2) generic(1) machine_uid_name(2)}.
      * The constant GSS_C_NT_MACHINE_UID_NAME should be
-     * initialized to point to that gss_OID_desc.
+     * initialized to point to that gss_OID_desc. */
+};
+const_gss_OID GSS_C_NT_MACHINE_UID_NAME = &oid_GSS_C_NT_MACHINE_UID_NAME;
+#endif
 
-     * The implementation must reserve static storage for a
+#ifndef GSS_C_NT_STRING_UID_NAME
+static gss_OID_desc oid_GSS_C_NT_STRING_UID_NAME = {
+    /* The implementation must reserve static storage for a
      * gss_OID_desc object containing the value */
-    {10, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x03"},
+    10, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x03",
     /* corresponding to an object-identifier value of
      * {iso(1) member-body(2) United States(840) mit(113554)
      * infosys(1) gssapi(2) generic(1) string_uid_name(3)}.
      * The constant GSS_C_NT_STRING_UID_NAME should be
-     * initialized to point to that gss_OID_desc.
+     * initialized to point to that gss_OID_desc. */
-     *
+};
-     * The implementation must reserve static storage for a
+const_gss_OID GSS_C_NT_STRING_UID_NAME = &oid_GSS_C_NT_STRING_UID_NAME;
+#endif
+
+#ifndef GSS_C_NT_HOSTBASED_SERVICE_X
+static gss_OID_desc oid_GSS_C_NT_HOSTBASED_SERVICE_X = {
+    /* The implementation must reserve static storage for a
      * gss_OID_desc object containing the value */
-    {6, (void *)"\x2b\x06\x01\x05\x06\x02"},
+    6, "\x2b\x06\x01\x05\x06\x02",
     /* corresponding to an object-identifier value of
      * {iso(1) org(3) dod(6) internet(1) security(5)
      * nametypes(6) gss-host-based-services(2))}.  The constant
@@ -52,29 +77,44 @@ static const gss_OID_desc oids[] = {
      * GSS_C_NT_HOSTBASED_SERVICE_X should be accepted a synonym
      * for GSS_C_NT_HOSTBASED_SERVICE when presented as an input
      * parameter, but should not be emitted by GSS-API
-     * implementations
+     * implementations */
-     *
+};
-     * The implementation must reserve static storage for a
+const_gss_OID GSS_C_NT_HOSTBASED_SERVICE_X = &oid_GSS_C_NT_HOSTBASED_SERVICE_X;
+#endif
+
+#ifndef GSS_C_NT_HOSTBASED_SERVICE
+static gss_OID_desc oid_GSS_C_NT_HOSTBASED_SERVICE = {
+    /* The implementation must reserve static storage for a
      * gss_OID_desc object containing the value */
-    {10, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x04"},
+    10, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x01\x04",
     /* corresponding to an object-identifier value of {iso(1)
      * member-body(2) Unites States(840) mit(113554) infosys(1)
      * gssapi(2) generic(1) service_name(4)}.  The constant
      * GSS_C_NT_HOSTBASED_SERVICE should be initialized
-     * to point to that gss_OID_desc.
+     * to point to that gss_OID_desc. */
-     *
+};
-     * The implementation must reserve static storage for a
+const_gss_OID GSS_C_NT_HOSTBASED_SERVICE = &oid_GSS_C_NT_HOSTBASED_SERVICE;
+#endif
+
+#ifndef GSS_C_NT_ANONYMOUS
+static gss_OID_desc oid_GSS_C_NT_ANONYMOUS = {
+    /* The implementation must reserve static storage for a
      * gss_OID_desc object containing the value */
-    {6, (void *)"\x2b\x06\01\x05\x06\x03"},
+    6, "\x2b\x06\01\x05\x06\x03",
     /* corresponding to an object identifier value of
      * {1(iso), 3(org), 6(dod), 1(internet), 5(security),
      * 6(nametypes), 3(gss-anonymous-name)}.  The constant
      * and GSS_C_NT_ANONYMOUS should be initialized to point
-     * to that gss_OID_desc.
+     * to that gss_OID_desc. */
-     *
+};
-     * The implementation must reserve static storage for a
+const_gss_OID GSS_C_NT_ANONYMOUS = &oid_GSS_C_NT_ANONYMOUS;
+#endif
+
+#ifndef GSS_C_NT_EXPORT_NAME
+static gss_OID_desc oid_GSS_C_NT_EXPORT_NAME = {
+    /* The implementation must reserve static storage for a
      * gss_OID_desc object containing the value */
-    {6, (void *)"\x2b\x06\x01\x05\x06\x04"},
+    6, "\x2b\x06\x01\x05\x06\x04",
     /* corresponding to an object-identifier value of
      * {1(iso), 3(org), 6(dod), 1(internet), 5(security),
      * 6(nametypes), 4(gss-api-exported-name)}.  The constant
@@ -82,23 +122,13 @@ static const gss_OID_desc oids[] = {
      * to that gss_OID_desc.
      */
 };
-
+const_gss_OID GSS_C_NT_EXPORT_NAME = &oid_GSS_C_NT_EXPORT_NAME;
-/* Here are the constants which point to the static structure above.
+#endif
- *
- * Constants of the form GSS_C_NT_* are specified by rfc 2744.
- */
-const_gss_OID GSS_C_NT_USER_NAME           = oids+0;
-const_gss_OID GSS_C_NT_MACHINE_UID_NAME    = oids+1;
-const_gss_OID GSS_C_NT_STRING_UID_NAME     = oids+2;
-const_gss_OID GSS_C_NT_HOSTBASED_SERVICE_X = oids+3;
-const_gss_OID GSS_C_NT_HOSTBASED_SERVICE   = oids+4;
-const_gss_OID GSS_C_NT_ANONYMOUS           = oids+5;
-const_gss_OID GSS_C_NT_EXPORT_NAME         = oids+6;
 
 #endif /* NO_LIBDL */
 
 static gss_OID_desc gss_mech_krb5_desc =
-{ 9, (void *)"\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" };
+{ 9, "\x2a\x86\x48\x86\xf7\x12\x01\x02\x02" };
 /* iso(1) member-body(2) United States(840) mit(113554) infosys(1) gssapi(2) krb5(2)*/
 const gss_OID GSS_MECH_KRB5 = &gss_mech_krb5_desc;