lib: yang: use common yang_ctx_new_setup()

After creating a libyang context, we need to hook up our callback to use
embedded built-in modules.  I hadn't added this to the yang translator
code.

Also, ly_ctx_new fails if the search directory doesn't exist.  Since
that's not a hard error for us, work around that and ignore inaccessible
YANG_MODELS_DIR.  (This is needed for snap packages.)

Signed-off-by: David Lamparter <equinox@diac24.net>

3 files changed, 31 insertions, 7 deletions

diff --git a/lib/yang.c b/lib/yang.c
index f62a8163f..1d8e82eb2 100644
--- a/lib/yang.c
+++ b/lib/yang.c
@@ -649,6 +649,29 @@ CPP_NOTICE("lib/yang: time to remove non-LIBYANG_EXT_BUILTIN support")
 extern struct lytype_plugin_list frr_user_types[];
 #endif
 
+struct ly_ctx *yang_ctx_new_setup(void)
+{
+	struct ly_ctx *ctx;
+	const char *yang_models_path = YANG_MODELS_PATH;
+
+	if (access(yang_models_path, R_OK | X_OK)) {
+		yang_models_path = NULL;
+		if (errno == ENOENT)
+			zlog_info("yang model directory \"%s\" does not exist",
+				  YANG_MODELS_PATH);
+		else
+			flog_err_sys(EC_LIB_LIBYANG,
+				     "cannot access yang model directory \"%s\"",
+				     YANG_MODELS_PATH);
+	}
+
+	ctx = ly_ctx_new(yang_models_path, LY_CTX_DISABLE_SEARCHDIR_CWD);
+	if (!ctx)
+		return NULL;
+	ly_ctx_set_module_imp_clb(ctx, yang_module_imp_clb, NULL);
+	return ctx;
+}
+
 void yang_init(void)
 {
 #ifndef LIBYANG_EXT_BUILTIN
@@ -677,13 +700,11 @@ CPP_NOTICE("lib/yang: deprecated libyang <0.16.74 extension loading in use!")
 #endif
 
 	/* Initialize libyang container for native models. */
-	ly_native_ctx =
-		ly_ctx_new(YANG_MODELS_PATH, LY_CTX_DISABLE_SEARCHDIR_CWD);
+	ly_native_ctx = yang_ctx_new_setup();
 	if (!ly_native_ctx) {
 		flog_err(EC_LIB_LIBYANG, "%s: ly_ctx_new() failed", __func__);
 		exit(1);
 	}
-	ly_ctx_set_module_imp_clb(ly_native_ctx, yang_module_imp_clb, NULL);
 	ly_ctx_set_priv_dup_clb(ly_native_ctx, ly_dup_cb);
 
 #ifndef LIBYANG_EXT_BUILTIN
diff --git a/lib/yang.h b/lib/yang.h
index 4680db08d..885218272 100644
--- a/lib/yang.h
+++ b/lib/yang.h
@@ -514,6 +514,11 @@ extern void yang_data_free(struct yang_data *data);
 extern struct list *yang_data_list_new(void);
 
 /*
+ * Create and set up a libyang context (for use by the translator)
+ */
+extern struct ly_ctx *yang_ctx_new_setup(void);
+
+/*
  * Initialize the YANG subsystem. Should be called only once during the
  * daemon initialization process.
  */
diff --git a/lib/yang_translator.c b/lib/yang_translator.c
index c3092e56e..6d6f92836 100644
--- a/lib/yang_translator.c
+++ b/lib/yang_translator.c
@@ -162,8 +162,7 @@ struct yang_translator *yang_translator_load(const char *path)
 	RB_INSERT(yang_translators, &yang_translators, translator);
 
 	/* Initialize the translator libyang context. */
-	translator->ly_ctx =
-		ly_ctx_new(YANG_MODELS_PATH, LY_CTX_DISABLE_SEARCHDIR_CWD);
+	translator->ly_ctx = yang_ctx_new_setup();
 	if (!translator->ly_ctx) {
 		flog_warn(EC_LIB_LIBYANG, "%s: ly_ctx_new() failed", __func__);
 		goto error;
@@ -525,8 +524,7 @@ static void str_replace(char *o_string, const char *s_string,
 
 void yang_translator_init(void)
 {
-	ly_translator_ctx =
-		ly_ctx_new(YANG_MODELS_PATH, LY_CTX_DISABLE_SEARCHDIR_CWD);
+	ly_translator_ctx = yang_ctx_new_setup();
 	if (!ly_translator_ctx) {
 		flog_err(EC_LIB_LIBYANG, "%s: ly_ctx_new() failed", __func__);
 		exit(1);