SYSDB: Add methods to deal with the domain's resolution order

In the following-up patches those newly introduced methods will be used
to deal with the domainResolutionOrder attribute.

The sysdb_update_domain_resolution_order() method is purposely not
checking whether a value has changed or not before writing to sysdb and
while may not be optimal, the readability of the code has increased a
lot by keeping it as simple as possible.

Tests for these new methods are part of the next commit.

Related:
https://pagure.io/SSSD/sssd/issue/3001

Signed-off-by: Fabiano Fidêncio <fidencio@redhat.com>

Reviewed-by: Sumit Bose <sbose@redhat.com>
Reviewed-by: Pavel Březina <pbrezina@redhat.com>

3 files changed, 208 insertions, 0 deletions

diff --git a/src/db/sysdb.h b/src/db/sysdb.h
index 6762b51be..42d2857ed 100644
--- a/src/db/sysdb.h
+++ b/src/db/sysdb.h
@@ -184,6 +184,8 @@
 #define SYSDB_OVERRIDE_GROUP_CLASS "groupOverride"
 #define SYSDB_OVERRIDE_DN "overrideDN"
 #define SYSDB_OVERRIDE_OBJECT_DN "overrideObjectDN"
+#define SYSDB_USE_DOMAIN_RESOLUTION_ORDER "useDomainResolutionOrder"
+#define SYSDB_DOMAIN_RESOLUTION_ORDER "domainResolutionOrder"
 
 #define SYSDB_NEXTID_FILTER "("SYSDB_NEXTID"=*)"
 
diff --git a/src/db/sysdb_domain_resolution_order.c b/src/db/sysdb_domain_resolution_order.c
new file mode 100644
index 000000000..63774461a
--- /dev/null
+++ b/src/db/sysdb_domain_resolution_order.c
@@ -0,0 +1,169 @@
+/*
+    Authors:
+        Fabiano Fidêncio <fidencio@redhat.com>
+
+    Copyright (C) 2017 Red Hat
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include <ldb.h>
+
+#include "db/sysdb.h"
+#include "db/sysdb_private.h"
+
+static errno_t
+sysdb_get_domain_resolution_order_string_attr(TALLOC_CTX *mem_ctx,
+                                              struct sysdb_ctx *sysdb,
+                                              struct ldb_dn *dn,
+                                              const char *const *attrs,
+                                              const char **_attr)
+{
+    TALLOC_CTX *tmp_ctx;
+    struct ldb_result *res;
+    const char *attr;
+    errno_t ret;
+
+    tmp_ctx = talloc_new(NULL);
+    if (tmp_ctx == NULL) {
+        return ENOMEM;
+    }
+
+    ret = ldb_search(sysdb->ldb, tmp_ctx, &res, dn, LDB_SCOPE_BASE, attrs,
+                     NULL);
+    if (ret != LDB_SUCCESS) {
+        ret = EIO;
+        goto done;
+    }
+
+    if (res->count > 1) {
+        DEBUG(SSSDBG_OP_FAILURE,
+              "Base search returned [%d] results, expected 1.\n", res->count);
+        ret = EINVAL;
+        goto done;
+    } else if (res->count == 0) {
+        ret = ENOENT;
+        goto done;
+    } else {
+        /* res->count == 1 */
+        attr = ldb_msg_find_attr_as_string(res->msgs[0], attrs[0], NULL);
+        if (attr == NULL) {
+            ret = ENOENT;
+            goto done;
+        }
+    }
+
+    *_attr = talloc_steal(mem_ctx, attr);
+
+    ret = EOK;
+
+done:
+    talloc_free(tmp_ctx);
+    return ret;
+}
+
+errno_t
+sysdb_get_domain_resolution_order(TALLOC_CTX *mem_ctx,
+                                  struct sysdb_ctx *sysdb,
+                                  struct ldb_dn *dn,
+                                  const char **_domain_resolution_order)
+{
+    TALLOC_CTX *tmp_ctx;
+    const char *domain_resolution_order = NULL;
+    const char *attrs[] = { SYSDB_DOMAIN_RESOLUTION_ORDER, NULL };
+    errno_t ret;
+
+    tmp_ctx = talloc_new(NULL);
+    if (tmp_ctx == NULL) {
+        return ENOMEM;
+    }
+
+    ret = sysdb_get_domain_resolution_order_string_attr(
+            tmp_ctx, sysdb, dn, attrs, &domain_resolution_order);
+    if (ret != EOK && ret != ENOENT) {
+        DEBUG(SSSDBG_OP_FAILURE,
+              "sysdb_get_domain_resolution_order_string_attr() failed "
+              "[%d]: [%s]",
+              ret, sss_strerror(ret));
+        goto done;
+    } else if (ret == ENOENT) {
+        *_domain_resolution_order = NULL;
+        goto done;
+    } else {
+        /* ret == EOK */
+        *_domain_resolution_order = talloc_steal(mem_ctx,
+                                                 domain_resolution_order);
+    }
+
+    ret = EOK;
+
+done:
+    talloc_free(tmp_ctx);
+    return ret;
+}
+
+errno_t
+sysdb_update_domain_resolution_order(struct sysdb_ctx *sysdb,
+                                     struct ldb_dn *dn,
+                                     const char *domain_resolution_order)
+{
+    TALLOC_CTX *tmp_ctx;
+    struct ldb_message *msg;
+    errno_t ret;
+
+    tmp_ctx = talloc_new(NULL);
+    if (tmp_ctx == NULL) {
+        return ENOMEM;
+    }
+
+    msg = ldb_msg_new(tmp_ctx);
+    if (msg == NULL) {
+        ret = ENOMEM;
+        goto done;
+    }
+
+    msg->dn = dn;
+
+    ret = ldb_msg_add_empty(msg, SYSDB_DOMAIN_RESOLUTION_ORDER,
+                            LDB_FLAG_MOD_REPLACE, NULL);
+    if (ret != LDB_SUCCESS) {
+        ret = sysdb_error_to_errno(ret);
+        goto done;
+    }
+
+    if (domain_resolution_order != NULL) {
+        ret = ldb_msg_add_string(msg, SYSDB_DOMAIN_RESOLUTION_ORDER,
+                                 domain_resolution_order);
+        if (ret != LDB_SUCCESS) {
+            ret = sysdb_error_to_errno(ret);
+            goto done;
+        }
+    }
+
+    ret = ldb_modify(sysdb->ldb, msg);
+    if (ret != LDB_SUCCESS) {
+        DEBUG(SSSDBG_OP_FAILURE,
+              "ldb_modify()_failed: [%s][%d][%s]\n",
+              ldb_strerror(ret), ret, ldb_errstring(sysdb->ldb));
+        ret = sysdb_error_to_errno(ret);
+        goto done;
+    }
+
+
+    ret = EOK;
+
+done:
+    talloc_free(tmp_ctx);
+    return ret;
+}
diff --git a/src/db/sysdb_domain_resolution_order.h b/src/db/sysdb_domain_resolution_order.h
new file mode 100644
index 000000000..45d2ea63f
--- /dev/null
+++ b/src/db/sysdb_domain_resolution_order.h
@@ -0,0 +1,37 @@
+/*
+    Authors:
+        Fabiano Fidêncio <fidencio@redhat.com>
+
+    Copyright (C) 2017 Red Hat
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef _SYSDB_DOMAIN_RESOLUTION_ORDER_H_
+#define _SYSDB_DOMAIN_RESOLUTION_ORDER_H_
+
+#include "db/sysdb.h"
+
+errno_t
+sysdb_get_domain_resolution_order(TALLOC_CTX *mem_ctx,
+                                  struct sysdb_ctx *sysdb,
+                                  struct ldb_dn *dn,
+                                  const char **_domain_resolution_order);
+
+errno_t
+sysdb_update_domain_resolution_order(struct sysdb_ctx *sysdb,
+                                     struct ldb_dn *dn,
+                                     const char *domain_resolution_order);
+
+#endif /* _SYSDB_DOMAIN_RESOLUTION_ORDER_H_ */