Introduce macro for common plugin structure elements

Heimdal's HDB plugin interface, and hence Samba's KDC that depends upon
it, doesn't work on 32-bit builds due to structure fields being arranged
in the wrong order. This problem presents itself in the form of
segmentation faults on 32-bit systems, but goes unnoticed on 64-bit
builds thanks to extra structure padding absorbing the errant fields.

This commit reorders the HDB plugin structure fields to prevent crashes
and introduces a common macro to ensure every plugin presents a
consistent interface.

Samba BUG: https://bugzilla.samba.org/show_bug.cgi?id=15110

Signed-off-by: Joseph Sutton <josephsutton@catalyst.net.nz>

lib/krb5/an2ln_plugin.h

@@ -36,6 +36,8 @@
 #ifndef HEIMDAL_KRB5_AN2LN_PLUGIN_H
 #define HEIMDAL_KRB5_AN2LN_PLUGIN_H 1
 
+#include <heimbase-svc.h>
+
 #define KRB5_PLUGIN_AN2LN "an2ln"
 #define KRB5_PLUGIN_AN2LN_VERSION_0 0
 
@@ -80,9 +82,7 @@ typedef krb5_error_code (KRB5_LIB_CALL *set_result_f)(void *, const char *);
  * @ingroup krb5_support
  */
 typedef struct krb5plugin_an2ln_ftable_desc {
-    int			minor_version;
-    krb5_error_code	(KRB5_LIB_CALL *init)(krb5_context, void **);
-    void		(KRB5_LIB_CALL *fini)(void *);
+    HEIM_PLUGIN_FTABLE_COMMON_ELEMENTS(krb5_context);
     krb5_error_code	(KRB5_LIB_CALL *an2ln)(void *, krb5_context, const char *,
 	                         krb5_const_principal, set_result_f, void *);
 } krb5plugin_an2ln_ftable;

lib/krb5/db_plugin.h

@@ -33,6 +33,8 @@
 #ifndef HEIMDAL_KRB5_DB_PLUGIN_H
 #define HEIMDAL_KRB5_DB_PLUGIN_H 1
 
+#include <heimbase-svc.h>
+
 #define KRB5_PLUGIN_DB "krb5_db_plug"
 #define KRB5_PLUGIN_DB_VERSION_0 0
 
@@ -59,9 +61,7 @@
  * @ingroup krb5_support
  */
 typedef struct krb5plugin_db_ftable_desc {
-    int			minor_version;
-    krb5_error_code	(KRB5_LIB_CALL *init)(krb5_context, void **);
-    void		(KRB5_LIB_CALL *fini)(void *);
+    HEIM_PLUGIN_FTABLE_COMMON_ELEMENTS(krb5_context);
 } krb5plugin_db_ftable;
 
 #endif /* HEIMDAL_KRB5_DB_PLUGIN_H */

lib/krb5/kuserok_plugin.h

@@ -32,6 +32,8 @@
 #ifndef HEIMDAL_KRB5_KUSEROK_PLUGIN_H
 #define HEIMDAL_KRB5_KUSEROK_PLUGIN_H 1
 
+#include <heimbase-svc.h>
+
 #define KRB5_PLUGIN_KUSEROK "krb5_plugin_kuserok"
 #define KRB5_PLUGIN_KUSEROK_VERSION_0 0
 
@@ -76,9 +78,7 @@
  * @ingroup krb5_support
  */
 typedef struct krb5plugin_kuserok_ftable_desc {
-    int			minor_version;
-    krb5_error_code	(KRB5_LIB_CALL *init)(krb5_context, void **);
-    void		(KRB5_LIB_CALL *fini)(void *);
+    HEIM_PLUGIN_FTABLE_COMMON_ELEMENTS(krb5_context);
     krb5_error_code	(KRB5_LIB_CALL *kuserok)(void *, krb5_context, const char *,
 				   unsigned int, const char *, const char *,
 				   krb5_const_principal,

lib/krb5/locate_plugin.h

@@ -38,6 +38,8 @@
 #ifndef HEIMDAL_KRB5_LOCATE_PLUGIN_H
 #define HEIMDAL_KRB5_LOCATE_PLUGIN_H 1
 
+#include <heimbase-svc.h>
+
 #define KRB5_PLUGIN_LOCATE "service_locator"
 #define KRB5_PLUGIN_LOCATE_VERSION 1
 #define KRB5_PLUGIN_LOCATE_VERSION_0 0
@@ -70,9 +72,7 @@ typedef krb5_error_code
 
 
 typedef struct krb5plugin_service_locate_ftable {
-    int			minor_version;
-    krb5_error_code	(KRB5_CALLCONV *init)(krb5_context, void **);
-    void		(KRB5_CALLCONV *fini)(void *);
+    HEIM_PLUGIN_FTABLE_COMMON_ELEMENTS(krb5_context);
     krb5plugin_service_locate_lookup_old old_lookup;
     krb5plugin_service_locate_lookup lookup; /* version 2 */
 } krb5plugin_service_locate_ftable;

lib/krb5/send_to_kdc_plugin.h

@@ -37,6 +37,7 @@
 #define HEIMDAL_KRB5_SEND_TO_KDC_PLUGIN_H 1
 
 #include <krb5.h>
+#include <heimbase-svc.h>
 
 #define KRB5_PLUGIN_SEND_TO_KDC "send_to_kdc"
 
@@ -61,9 +62,7 @@ typedef krb5_error_code
 
 
 typedef struct krb5plugin_send_to_kdc_ftable {
-    int			minor_version;
-    krb5_error_code	(KRB5_CALLCONV *init)(krb5_context, void **);
-    void		(KRB5_CALLCONV *fini)(void *);
+    HEIM_PLUGIN_FTABLE_COMMON_ELEMENTS(krb5_context);
     krb5plugin_send_to_kdc_func send_to_kdc;
     krb5plugin_send_to_realm_func send_to_realm; /* added in version 2 */
 } krb5plugin_send_to_kdc_ftable;