replmd: Split checking link attr target into new function

We want to re-use this code to check that the linked attribute's target
object exists *before* we try to commit the transaction. This will allow
us to re-request the block with the GET_TGT flag set.

This splits checking the target object exists into a separate function.

Minor changes of note:
- the 'parent' argument was passed to replmd_process_linked_attribute()
  as NULL, so I've just replaced where it was used in the refactored code
  with NULL.
- I've tweaked the "Failed to find GUID" error message slightly to display
  the attribute ID rather than the attribute name (saves repeating
  lookups and/or passing extra arguments).
- Tweaked the replmd_deletion_state() logic - it only made sense to call
  it in the code block where we actually found the target

Signed-off-by: Tim Beale <timbeale@catalyst.net.nz>
Reviewed-by: Garming Sam <garming@samba.org>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>
BUG: https://bugzilla.samba.org/show_bug.cgi?id=12972

diff --git a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
index 0ed24cb593e30fdaad2fd8293d0d225465aedda9..53e2c12c841101e7f0dfc683e4d03e4f15854cbf 100644 (file)
--- a/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
+++ b/source4/dsdb/samdb/ldb_modules/repl_meta_data.c
@@ -6627,6 +6627,105 @@ static int replmd_extended_replicated_objects(struct ldb_module *module, struct
        return replmd_replicated_apply_next(ar);
 }
 
+/**
+ * Checks that the target object for a linked attribute exists.
+ * If it exists, its GUID and deletion-state are returned
+ */
+static int replmd_check_target_exists(struct ldb_module *module,
+                                     struct dsdb_dn *dsdb_dn,
+                                     struct la_entry *la_entry,
+                                     struct ldb_dn *source_dn,
+                                     struct GUID *guid,
+                                     enum deletion_state *target_deletion_state)
+{
+       struct drsuapi_DsReplicaLinkedAttribute *la = la_entry->la;
+       struct ldb_context *ldb = ldb_module_get_ctx(module);
+       struct ldb_result *target_res;
+       TALLOC_CTX *tmp_ctx = talloc_new(la_entry);
+       const char *attrs[] = { "isDeleted", "isRecycled", NULL };
+       NTSTATUS ntstatus;
+       int ret;
+       bool active = (la->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE) ? true : false;
+
+       *target_deletion_state = OBJECT_REMOVED;
+
+       ntstatus = dsdb_get_extended_dn_guid(dsdb_dn->dn, guid, "GUID");
+
+       if (!NT_STATUS_IS_OK(ntstatus) && !active) {
+
+               /*
+                * This strange behaviour (allowing a NULL/missing
+                * GUID) originally comes from:
+                *
+                * commit e3054ce0fe0f8f62d2f5b2a77893e7a1479128bd
+                * Author: Andrew Tridgell <tridge@samba.org>
+                * Date:   Mon Dec 21 21:21:55 2009 +1100
+                *
+                *  s4-drs: cope better with NULL GUIDS from DRS
+                *
+                *  It is valid to get a NULL GUID over DRS for a deleted forward link. We
+                *  need to match by DN if possible when seeing if we should update an
+                *  existing link.
+                *
+                *  Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>
+                */
+               ret = dsdb_module_search_dn(module, tmp_ctx, &target_res,
+                                           dsdb_dn->dn, attrs,
+                                           DSDB_FLAG_NEXT_MODULE |
+                                           DSDB_SEARCH_SHOW_RECYCLED |
+                                           DSDB_SEARCH_SEARCH_ALL_PARTITIONS |
+                                           DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT,
+                                           NULL);
+       } else if (!NT_STATUS_IS_OK(ntstatus)) {
+               ldb_asprintf_errstring(ldb, "Failed to find GUID in linked attribute 0x%x blob for %s from %s",
+                                      la->attid,
+                                      ldb_dn_get_linearized(dsdb_dn->dn),
+                                      ldb_dn_get_linearized(source_dn));
+               talloc_free(tmp_ctx);
+               return LDB_ERR_OPERATIONS_ERROR;
+       } else {
+               ret = dsdb_module_search(module, tmp_ctx, &target_res,
+                                        NULL, LDB_SCOPE_SUBTREE,
+                                        attrs,
+                                        DSDB_FLAG_NEXT_MODULE |
+                                        DSDB_SEARCH_SHOW_RECYCLED |
+                                        DSDB_SEARCH_SEARCH_ALL_PARTITIONS |
+                                        DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT,
+                                        NULL,
+                                        "objectGUID=%s",
+                                        GUID_string(tmp_ctx, guid));
+       }
+
+       if (ret != LDB_SUCCESS) {
+               ldb_asprintf_errstring(ldb, "Failed to re-resolve GUID %s: %s\n",
+                                      GUID_string(tmp_ctx, guid),
+                                      ldb_errstring(ldb));
+               talloc_free(tmp_ctx);
+               return ret;
+       }
+
+       if (target_res->count == 0) {
+               DEBUG(2,(__location__ ": WARNING: Failed to re-resolve GUID %s - using %s\n",
+                        GUID_string(tmp_ctx, guid),
+                        ldb_dn_get_linearized(dsdb_dn->dn)));
+       } else if (target_res->count != 1) {
+               ldb_asprintf_errstring(ldb, "More than one object found matching objectGUID %s\n",
+                                      GUID_string(tmp_ctx, guid));
+               ret = LDB_ERR_OPERATIONS_ERROR;
+       } else {
+               struct ldb_message *target_msg = target_res->msgs[0];
+
+               dsdb_dn->dn = talloc_steal(dsdb_dn, target_msg->dn);
+
+               /* Get the object's state (i.e. Not Deleted, Tombstone, etc) */
+               replmd_deletion_state(module, target_msg,
+                                     target_deletion_state, NULL);
+       }
+
+       talloc_free(tmp_ctx);
+       return ret;
+}
+
 /*
   process one linked attribute structure
  */
@@ -6638,7 +6737,6 @@ static int replmd_process_linked_attribute(struct ldb_module *module,
        struct drsuapi_DsReplicaLinkedAttribute *la = la_entry->la;
        struct ldb_context *ldb = ldb_module_get_ctx(module);
        struct ldb_message *msg;
-       struct ldb_message *target_msg = NULL;
        TALLOC_CTX *tmp_ctx = talloc_new(la_entry);
        const struct dsdb_schema *schema = dsdb_get_schema(ldb, tmp_ctx);
        int ret;
@@ -6649,17 +6747,15 @@ static int replmd_process_linked_attribute(struct ldb_module *module,
        WERROR status;
        time_t t = time(NULL);
        struct ldb_result *res;
-       struct ldb_result *target_res;
        const char *attrs[4];
-       const char *attrs2[] = { "isDeleted", "isRecycled", NULL };
        struct parsed_dn *pdn_list, *pdn, *next;
        struct GUID guid = GUID_zero();
-       NTSTATUS ntstatus;
        bool active = (la->flags & DRSUAPI_DS_LINKED_ATTRIBUTE_FLAG_ACTIVE)?true:false;
 
        enum deletion_state deletion_state = OBJECT_NOT_DELETED;
        enum deletion_state target_deletion_state = OBJECT_NOT_DELETED;
 
+
 /*
 linked_attributes[0]:
      &objs->linked_attributes[i]: struct drsuapi_DsReplicaLinkedAttribute
@@ -6779,74 +6875,14 @@ linked_attributes[0]:
                return LDB_ERR_OPERATIONS_ERROR;
        }
 
-       ntstatus = dsdb_get_extended_dn_guid(dsdb_dn->dn, &guid, "GUID");
-       if (!NT_STATUS_IS_OK(ntstatus) && !active) {
-               /*
-                * This strange behaviour (allowing a NULL/missing
-                * GUID) originally comes from:
-                *
-                * commit e3054ce0fe0f8f62d2f5b2a77893e7a1479128bd
-                * Author: Andrew Tridgell <tridge@samba.org>
-                * Date:   Mon Dec 21 21:21:55 2009 +1100
-                *
-                *  s4-drs: cope better with NULL GUIDS from DRS
-                *
-                *  It is valid to get a NULL GUID over DRS for a deleted forward link. We
-                *  need to match by DN if possible when seeing if we should update an
-                *  existing link.
-                *
-                *  Pair-Programmed-With: Andrew Bartlett <abartlet@samba.org>
-                */
-
-               ret = dsdb_module_search_dn(module, tmp_ctx, &target_res,
-                                           dsdb_dn->dn, attrs2,
-                                           DSDB_FLAG_NEXT_MODULE |
-                                           DSDB_SEARCH_SHOW_RECYCLED |
-                                           DSDB_SEARCH_SEARCH_ALL_PARTITIONS |
-                                           DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT,
-                                           parent);
-       } else if (!NT_STATUS_IS_OK(ntstatus)) {
-               ldb_asprintf_errstring(ldb, "Failed to find GUID in linked attribute blob for %s on %s from %s",
-                                      old_el->name,
-                                      ldb_dn_get_linearized(dsdb_dn->dn),
-                                      ldb_dn_get_linearized(msg->dn));
-               talloc_free(tmp_ctx);
-               return LDB_ERR_OPERATIONS_ERROR;
-       } else {
-               ret = dsdb_module_search(module, tmp_ctx, &target_res,
-                                        NULL, LDB_SCOPE_SUBTREE,
-                                        attrs2,
-                                        DSDB_FLAG_NEXT_MODULE |
-                                        DSDB_SEARCH_SHOW_RECYCLED |
-                                        DSDB_SEARCH_SEARCH_ALL_PARTITIONS |
-                                        DSDB_SEARCH_SHOW_DN_IN_STORAGE_FORMAT,
-                                        parent,
-                                        "objectGUID=%s",
-                                        GUID_string(tmp_ctx, &guid));
-       }
+       ret = replmd_check_target_exists(module, dsdb_dn, la_entry, msg->dn,
+                                        &guid, &target_deletion_state);
 
        if (ret != LDB_SUCCESS) {
-               ldb_asprintf_errstring(ldb_module_get_ctx(module), "Failed to re-resolve GUID %s: %s\n",
-                                      GUID_string(tmp_ctx, &guid),
-                                      ldb_errstring(ldb_module_get_ctx(module)));
                talloc_free(tmp_ctx);
                return ret;
        }
 
-       if (target_res->count == 0) {
-               DEBUG(2,(__location__ ": WARNING: Failed to re-resolve GUID %s - using %s\n",
-                        GUID_string(tmp_ctx, &guid),
-                        ldb_dn_get_linearized(dsdb_dn->dn)));
-       } else if (target_res->count != 1) {
-               ldb_asprintf_errstring(ldb_module_get_ctx(module), "More than one object found matching objectGUID %s\n",
-                                      GUID_string(tmp_ctx, &guid));
-               talloc_free(tmp_ctx);
-               return LDB_ERR_OPERATIONS_ERROR;
-       } else {
-               target_msg = target_res->msgs[0];
-               dsdb_dn->dn = talloc_steal(dsdb_dn, target_msg->dn);
-       }
-
        /*
         * Check for deleted objects per MS-DRSR 4.1.10.6.13
         * ProcessLinkValue, because link updates are not applied to
@@ -6854,9 +6890,6 @@ linked_attributes[0]:
         * any existing link, that should have happened when the
         * object deletion was replicated or initiated.
         */
-       replmd_deletion_state(module, target_msg,
-                             &target_deletion_state, NULL);
-
        if (target_deletion_state >= OBJECT_RECYCLED) {
                talloc_free(tmp_ctx);
                return LDB_SUCCESS;