Change the way domains are linked.

- Use a double-linked list for domains and subdomains.
- Never remove a subdomain, simply mark it as disabled if it becomes
  unused.
- Rework the way subdomains are refreshed.
  Now sysdb_update_subdomains() actually updates the current subdomains
  and marks as disabled the ones not found in the sysdb or add new ones
  found. It never removes them.
  Removal of missing domains from sysdb is deferred to the providers,
  which will perform it at refresh time, for the ipa provider that is
  done by ipa_subdomains_write_mappings() now.
  sysdb_update_subdomains() is then used to update the memory hierarchy
  of the subdomains.

- Removes sysdb_get_subdomains()
- Removes copy_subdomain()
- Add sysdb_subdomain_delete()

2 files changed, 68 insertions, 106 deletions

diff --git a/src/db/sysdb.h b/src/db/sysdb.h
index 2bc858ed..fff97a8a 100644
--- a/src/db/sysdb.h
+++ b/src/db/sysdb.h
@@ -355,11 +355,6 @@ int sysdb_transaction_commit(struct sysdb_ctx *sysdb);
 int sysdb_transaction_cancel(struct sysdb_ctx *sysdb);
 
 /* functions related to subdomains */
-errno_t sysdb_get_subdomains(TALLOC_CTX *mem_ctx,
-                             struct sss_domain_info *domain,
-                             size_t *subdomain_count,
-                             struct sss_domain_info ***subdomain_list);
-
 errno_t sysdb_domain_create(struct sysdb_ctx *sysdb, const char *domain_name);
 
 errno_t sysdb_subdomain_store(struct sysdb_ctx *sysdb,
@@ -374,6 +369,8 @@ errno_t sysdb_master_domain_add_info(struct sss_domain_info *domain,
                                      const char *realm, const char *flat,
                                      const char *id);
 
+errno_t sysdb_subdomain_delete(struct sysdb_ctx *sysdb, const char *name);
+
 errno_t sysdb_get_ranges(TALLOC_CTX *mem_ctx, struct sysdb_ctx *sysdb,
                              size_t *range_count,
                              struct range_info ***range_list);
diff --git a/src/db/sysdb_subdomains.c b/src/db/sysdb_subdomains.c
index c2719075..3e0d7b40 100644
--- a/src/db/sysdb_subdomains.c
+++ b/src/db/sysdb_subdomains.c
@@ -23,10 +23,7 @@
 #include "util/util.h"
 #include "db/sysdb_private.h"
 
-errno_t sysdb_get_subdomains(TALLOC_CTX *mem_ctx,
-                             struct sss_domain_info *domain,
-                             size_t *subdomain_count,
-                             struct sss_domain_info ***subdomain_list)
+errno_t sysdb_update_subdomains(struct sss_domain_info *domain)
 {
     int i;
     errno_t ret;
@@ -37,7 +34,7 @@ errno_t sysdb_get_subdomains(TALLOC_CTX *mem_ctx,
                            SYSDB_SUBDOMAIN_FLAT,
                            SYSDB_SUBDOMAIN_ID,
                            NULL};
-    struct sss_domain_info **list;
+    struct sss_domain_info *dom;
     struct ldb_dn *basedn;
 
     tmp_ctx = talloc_new(NULL);
@@ -59,10 +56,14 @@ errno_t sysdb_get_subdomains(TALLOC_CTX *mem_ctx,
         goto done;
     }
 
-    list = talloc_zero_array(tmp_ctx, struct sss_domain_info *,
-                             res->count + 1);
-    if (list == NULL) {
-        ret = ENOMEM;
+    /* disable all domains,
+     * let the search result refresh any that are still valid */
+    for (dom = domain->subdomains; dom; dom = get_next_domain(dom, false)) {
+        dom->disabled = true;
+    }
+
+    if (res->count == 0) {
+        ret = EOK;
         goto done;
     }
 
@@ -90,17 +91,58 @@ errno_t sysdb_get_subdomains(TALLOC_CTX *mem_ctx,
         id = ldb_msg_find_attr_as_string(res->msgs[i],
                                          SYSDB_SUBDOMAIN_ID, NULL);
 
-        list[i] = new_subdomain(list, domain, name, realm, flat, id);
-        if (list[i] == NULL) {
-            ret = ENOMEM;
-            goto done;
+        /* explicitly use dom->next as we need to check 'disabled' domains */
+        for (dom = domain->subdomains; dom; dom = dom->next) {
+            if (strcasecmp(dom->name, name) == 0) {
+                dom->disabled = false;
+                /* in theory these may change, but it should never happen */
+                if (strcasecmp(dom->realm, realm) != 0) {
+                    DEBUG(SSSDBG_TRACE_INTERNAL,
+                          ("Realm name changed from [%s] to [%s]!\n",
+                           dom->realm, realm));
+                    talloc_zfree(dom->realm);
+                    dom->realm = talloc_strdup(dom, realm);
+                    if (dom->realm == NULL) {
+                        ret = ENOMEM;
+                        goto done;
+                    }
+                }
+                if (strcasecmp(dom->flat_name, flat) != 0) {
+                    DEBUG(SSSDBG_TRACE_INTERNAL,
+                          ("Flat name changed from [%s] to [%s]!\n",
+                           dom->flat_name, flat));
+                    talloc_zfree(dom->flat_name);
+                    dom->flat_name = talloc_strdup(dom, flat);
+                    if (dom->flat_name == NULL) {
+                        ret = ENOMEM;
+                        goto done;
+                    }
+                }
+                if (strcasecmp(dom->domain_id, id) != 0) {
+                    DEBUG(SSSDBG_TRACE_INTERNAL,
+                          ("Domain changed from [%s] to [%s]!\n",
+                           dom->domain_id, id));
+                    talloc_zfree(dom->domain_id);
+                    dom->domain_id = talloc_strdup(dom, id);
+                    if (dom->domain_id == NULL) {
+                        ret = ENOMEM;
+                        goto done;
+                    }
+                }
+                break;
+            }
+        }
+        /* If not found in loop it is a new subdomain */
+        if (dom == NULL) {
+            dom = new_subdomain(domain, domain, name, realm, flat, id);
+            if (dom == NULL) {
+                ret = ENOMEM;
+                goto done;
+            }
+            DLIST_ADD_END(domain->subdomains, dom, struct sss_domain_info *);
         }
     }
 
-    list[res->count] = NULL;
-
-    *subdomain_count = res->count;
-    *subdomain_list = talloc_steal(mem_ctx, list);
     ret = EOK;
 
 done:
@@ -460,18 +502,11 @@ done:
     return ret;
 }
 
-errno_t sysdb_update_subdomains(struct sss_domain_info *domain)
+errno_t sysdb_subdomain_delete(struct sysdb_ctx *sysdb, const char *name)
 {
-    int ret;
-    int sret;
-    size_t c;
-    size_t d;
     TALLOC_CTX *tmp_ctx = NULL;
-    size_t cur_subdomains_count;
-    struct sss_domain_info **cur_subdomains;
     struct ldb_dn *dn;
-    bool in_transaction = false;
-    bool *keep_subdomain;
+    int ret;
 
     tmp_ctx = talloc_new(NULL);
     if (tmp_ctx == NULL) {
@@ -479,90 +514,20 @@ errno_t sysdb_update_subdomains(struct sss_domain_info *domain)
         goto done;
     }
 
-    /* Retrieve all subdomains that are currently in sysdb */
-    ret = sysdb_get_subdomains(tmp_ctx, domain, &cur_subdomains_count,
-                               &cur_subdomains);
-    if (ret != EOK) {
-        DEBUG(SSSDBG_OP_FAILURE, ("sysdb_get_subdomains failed.\n"));
-        goto done;
-    }
-
-    keep_subdomain = talloc_zero_array(tmp_ctx, bool, cur_subdomains_count);
-    if (keep_subdomain == NULL) {
+    DEBUG(SSSDBG_TRACE_FUNC, ("Removing sub-domain [%s] from db.\n", name));
+    dn = ldb_dn_new_fmt(tmp_ctx, sysdb->ldb, SYSDB_DOM_BASE, name);
+    if (dn == NULL) {
         ret = ENOMEM;
-        DEBUG(SSSDBG_OP_FAILURE, ("talloc_zero_array failed.\n"));
         goto done;
     }
 
-    ret = sysdb_transaction_start(domain->sysdb);
+    ret = sysdb_delete_recursive(sysdb, dn, true);
     if (ret != EOK) {
-        DEBUG(SSSDBG_OP_FAILURE, ("sysdb_transaction_start failed.\n"));
+        DEBUG(SSSDBG_OP_FAILURE, ("sysdb_delete_recursive failed.\n"));
         goto done;
     }
-    in_transaction = true;
-
-    /* Go through a list of retrieved subdomains and:
-     * - if a subdomain already exists in sysdb, mark it for preservation
-     * - if the subdomain doesn't exist in sysdb, create its bare structure
-     */
-    for (c = 0; c < domain->subdomain_count; c++) {
-        for (d = 0; d < cur_subdomains_count; d++) {
-            if (strcasecmp(domain->subdomains[c]->name,
-                           cur_subdomains[d]->name) == 0) {
-                keep_subdomain[d] = true;
-                /* sub-domain already in cache, nothing to do */
-                break;
-            }
-        }
-
-        if (d == cur_subdomains_count) {
-            DEBUG(SSSDBG_TRACE_FUNC, ("Adding sub-domain [%s].\n",
-                                      domain->subdomains[c]->name));
-            ret = sysdb_subdomain_create(domain->subdomains[c]);
-            if (ret != EOK) {
-                DEBUG(SSSDBG_OP_FAILURE, ("sysdb_subdomain_create failed.\n"));
-                goto done;
-            }
-        }
-    }
-
-    /* Now delete all subdomains that have been in sysdb prior to
-     * refreshing the list and are not marked for preservation
-     * (i.e. they are not in the new list of subdomains)
-     */
-    for (d = 0; d < cur_subdomains_count; d++) {
-        if (!keep_subdomain[d]) {
-            DEBUG(SSSDBG_TRACE_FUNC, ("Removing sub-domain [%s].\n",
-                                      cur_subdomains[d]->name));
-            dn = ldb_dn_new_fmt(tmp_ctx, domain->sysdb->ldb, SYSDB_DOM_BASE,
-                                cur_subdomains[d]->name);
-            if (dn == NULL) {
-                ret = ENOMEM;
-                goto done;
-            }
-
-            ret = sysdb_delete_recursive(domain->sysdb, dn, true);
-            if (ret != EOK) {
-                DEBUG(SSSDBG_OP_FAILURE, ("sysdb_delete_recursive failed.\n"));
-                goto done;
-            }
-        }
-    }
-
-    ret = sysdb_transaction_commit(domain->sysdb);
-    if (ret != EOK) {
-        DEBUG(SSSDBG_MINOR_FAILURE, ("Could not commit transaction\n"));
-        goto done;
-    }
-    in_transaction = false;
 
 done:
-    if (in_transaction) {
-        sret = sysdb_transaction_cancel(domain->sysdb);
-        if (sret != EOK) {
-            DEBUG(SSSDBG_CRIT_FAILURE, ("Could not cancel transaction\n"));
-        }
-    }
     talloc_free(tmp_ctx);
     return ret;
 }