From 9859f308d23bf12a7f454ae65dada6d90f4c31db Mon Sep 17 00:00:00 2001
From: Igor Ryzhov <iryzhov@nfware.com>
Date: Sun, 14 Jan 2024 00:53:21 +0200
Subject: [PATCH] lib, mgmtd: add ability to request the exact node in get-data
 request

RESTCONF expects to receive the exact node as a result, not the whole
data tree.

Signed-off-by: Igor Ryzhov <iryzhov@nfware.com>
---
 lib/mgmt_msg_native.h |  1 +
 mgmtd/mgmt_txn.c      | 10 +++++++++-
 mgmtd/mgmt_vty.c      |  6 +++++-
 3 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/lib/mgmt_msg_native.h b/lib/mgmt_msg_native.h
index 88c1065fc84e..069cb9b15075 100644
--- a/lib/mgmt_msg_native.h
+++ b/lib/mgmt_msg_native.h
@@ -236,6 +236,7 @@ _Static_assert(sizeof(struct mgmt_msg_tree_data) ==
 /* Flags for get-data request */
 #define GET_DATA_FLAG_STATE	0x01	/* get only "config false" data */
 #define GET_DATA_FLAG_CONFIG	0x02	/* get only "config true" data */
+#define GET_DATA_FLAG_EXACT	0x04	/* get exact data node instead of the full tree */
 
 /**
  * struct mgmt_msg_get_data - frontend get-data request.
diff --git a/mgmtd/mgmt_txn.c b/mgmtd/mgmt_txn.c
index 3a2a23d9e9d8..842e13cf117b 100644
--- a/mgmtd/mgmt_txn.c
+++ b/mgmtd/mgmt_txn.c
@@ -176,6 +176,7 @@ struct txn_req_get_tree {
 	uint64_t recv_clients; /* Bitmask of clients recv reply from */
 	int32_t partial_error; /* an error while gather results */
 	uint8_t result_type;   /* LYD_FORMAT for results */
+	uint8_t exact;	       /* if exact node is requested */
 	uint8_t simple_xpath;  /* if xpath is simple */
 	struct lyd_node *client_results; /* result tree from clients */
 };
@@ -1258,6 +1259,7 @@ static int txn_get_tree_data_done(struct mgmt_txn_ctx *txn,
 {
 	struct txn_req_get_tree *get_tree = txn_req->req.get_tree;
 	uint64_t req_id = txn_req->req_id;
+	struct lyd_node *result;
 	int ret = NB_OK;
 
 	/* cancel timer and send reply onward */
@@ -1272,12 +1274,17 @@ static int txn_get_tree_data_done(struct mgmt_txn_ctx *txn,
 			ret = NB_ERR;
 	}
 
+	result = get_tree->client_results;
+
+	if (ret == NB_OK && result && get_tree->exact)
+		result = yang_dnode_get(result, get_tree->xpath);
+
 	if (ret == NB_OK)
 		ret = mgmt_fe_adapter_send_tree_data(txn->session_id,
 						     txn->txn_id,
 						     txn_req->req_id,
 						     get_tree->result_type,
-						     get_tree->client_results,
+						     result,
 						     get_tree->partial_error,
 						     false);
 
@@ -2383,6 +2390,7 @@ int mgmt_txn_send_get_tree_oper(uint64_t txn_id, uint64_t req_id,
 	txn_req = mgmt_txn_req_alloc(txn, req_id, MGMTD_TXN_PROC_GETTREE);
 	get_tree = txn_req->req.get_tree;
 	get_tree->result_type = result_type;
+	get_tree->exact = CHECK_FLAG(flags, GET_DATA_FLAG_EXACT);
 	get_tree->simple_xpath = simple_xpath;
 	get_tree->xpath = XSTRDUP(MTYPE_MGMTD_XPATH, xpath);
 
diff --git a/mgmtd/mgmt_vty.c b/mgmtd/mgmt_vty.c
index e6f74c31290e..f4b24acf3ace 100644
--- a/mgmtd/mgmt_vty.c
+++ b/mgmtd/mgmt_vty.c
@@ -251,13 +251,14 @@ DEFPY(show_mgmt_get_config, show_mgmt_get_config_cmd,
 }
 
 DEFPY(show_mgmt_get_data, show_mgmt_get_data_cmd,
-      "show mgmt get-data WORD$path [with-config|only-config]$content [json|xml]$fmt",
+      "show mgmt get-data WORD$path [with-config|only-config]$content [exact]$exact [json|xml]$fmt",
       SHOW_STR
       MGMTD_STR
       "Get a data from the operational datastore\n"
       "XPath expression specifying the YANG data root\n"
       "Include \"config true\" data\n"
       "Get only \"config true\" data\n"
+      "Get exact node instead of the whole data tree\n"
       "JSON output format\n"
       "XML output format\n")
 {
@@ -269,6 +270,9 @@ DEFPY(show_mgmt_get_data, show_mgmt_get_data_cmd,
 	if (content && content[0] == 'w')
 		flags |= GET_DATA_FLAG_STATE;
 
+	if (exact)
+		flags |= GET_DATA_FLAG_EXACT;
+
 	/* get rid of extraneous trailing slash-* or single '/' unless root */
 	if (plen > 2 && ((path[plen - 2] == '/' && path[plen - 1] == '*') ||
 			 (path[plen - 2] != '/' && path[plen - 1] == '/'))) {