Changed plugin_init() backend return semantics: If returns NULL, _without_ calling clicon_err(), the module is disabled.

Also, example documentation corrected according to:
https://github.com/clicon/clixon/issues/33

CHANGELOG.md

@@ -9,7 +9,8 @@
   * Applications which have not strictly enforced the identities may now have problems with validation and may need to be modified.
 	
 ### Minor changes:
-* Dedicated xml,json,yang and xsl parser utility programs added
+* Changed `plugin_init()` backend return semantics: If returns NULL, _without_ calling clicon_err(), the module is disabled.
+* Dedicated standalone xml,json,yang and xsl parser utility test programs added under lib/src/.
 * CDATA xml support (patch by David Cornejo, Netgate)
   * Encode and decode (parsing) support 
 * Validation of yang bits type space-separated list value

example/README.md

@@ -23,7 +23,7 @@ routing example. It contains the following files:
 ```
 Start backend:
 ```
-    clixon_backend -f /usr/local/etc/example.xml -I
+    sudo clixon_backend -f /usr/local/etc/example.xml -s init
 ```
 Edit cli:
 ```

example/example_backend_nacm.c

@@ -114,6 +114,13 @@ static clixon_plugin_api api = {
 clixon_plugin_api *
 clixon_plugin_init(clicon_handle h)
 {
+    char                *nacm_mode;
+    
     clicon_debug(1, "%s backend nacm", __FUNCTION__);
+    nacm_mode = clicon_option_str(h, "CLICON_NACM_MODE");
+    if (nacm_mode==NULL || strcmp(nacm_mode, "disabled") == 0){
+	clicon_debug(1, "%s CLICON_NACM_MODE not enabled: example nacm module disabled", __FUNCTION__);
+	return NULL;
+    }
     return &api;
 }

lib/clixon/clixon_plugin.h

@@ -41,7 +41,9 @@
 /*
  * Constants
  */
-/* Hardcoded plugin symbol. Must exist in all plugins to kickstart */
+/* Hardcoded plugin symbol. Must exist in all plugins to kickstart 
+ * @see clixon_plugin_init
+ */
 #define CLIXON_PLUGIN_INIT     "clixon_plugin_init" 
 
 /*
@@ -181,6 +183,7 @@ typedef struct clixon_plugin clixon_plugin;
 /*! Plugin initialization function. Must appear in all plugins
  * @param[in]  h    Clixon handle
  * @retval     api  Pointer to API struct
+ * @retval     NULL Failure (if clixon_err() called), module disabled otherwise.
  * @see CLIXON_PLUGIN_INIT  default symbol 
  */
 clixon_plugin_api *clixon_plugin_init(clicon_handle h);

lib/src/clixon_plugin.c

@@ -43,6 +43,7 @@
 #include <errno.h>
 #include <dlfcn.h>
 #include <dirent.h>
+#include <syslog.h>
 
 #include <sys/stat.h>
 #include <sys/param.h>
@@ -204,13 +205,17 @@ plugin_load_one(clicon_handle   h,
 	clicon_err(OE_UNIX, 0, "dlsym: %s: %s", file, error);
 	goto done;
     }
+    clicon_err_reset();
     if ((api = initfn(h)) == NULL) {
+	if (!clicon_errno){ 	/* if clicon_err() is not called then log and continue */
+	    clicon_log(LOG_WARNING, "Warning: failed to initiate %s", strrchr(file,'/')?strchr(file, '/'):file);
+	    dlclose(handle);
+	}
+	else{
 	    clicon_err(OE_PLUGIN, errno, "Failed to initiate %s", strrchr(file,'/')?strchr(file, '/'):file);
-	if (!clicon_errno) 	/* sanity: log if clicon_err() is not called ! */
-	    clicon_err(OE_DB, 0, "Unknown error: %s: plugin_init does not make clicon_err call on error",
-		       file);
 	    goto err;
 	}
+    }
     /* Note: sizeof clixon_plugin_api which is largest of clixon_plugin_api:s */
     if ((cp = (clixon_plugin *)malloc(sizeof(struct clixon_plugin))) == NULL){
 	clicon_err(OE_UNIX, errno, "malloc");
@@ -228,6 +233,7 @@ plugin_load_one(clicon_handle   h,
 
     snprintf(cp->cp_name, sizeof(cp->cp_name), "%*s",
 	     (int)strlen(name), name);
+    if (api)
 	cp->cp_api = *api;
     clicon_debug(1, "%s", __FUNCTION__);
  done:

lib/src/clixon_xml.c

@@ -1487,8 +1487,6 @@ int
 xml_copy_one(cxobj *x0, 
 	     cxobj *x1)
 {
-    cg_var *cv1;
-
     xml_type_set(x1, xml_type(x0));
     if (xml_value(x0)){ /* malloced string */
 	if ((x1->x_value = strdup(x0->x_value)) == NULL){

lib/src/clixon_xml_map.c

@@ -1715,6 +1715,7 @@ xml_merge1(cxobj              *x0,
     cxobj     *x1c; /* mod child */
     char      *x1bstr; /* mod body string */
     yang_stmt *yc;  /* yang child */
+    cbuf      *cbr = NULL; /* Reason buffer */
 
     assert(x1 && xml_type(x1) == CX_ELMNT);
     assert(y0);
@@ -1753,10 +1754,17 @@ xml_merge1(cxobj              *x0,
 	    x1cname = xml_name(x1c);
 	    /* Get yang spec of the child */
 	    if ((yc = yang_find_datanode(y0, x1cname)) == NULL){
-		if (reason && (*reason = strdup("XML node has no corresponding yang specification (Invalid XML or wrong Yang spec?")) == NULL){
+		if (reason){
+		    if ((cbr = cbuf_new()) == NULL){
+			clicon_err(OE_XML, errno, "cbuf_new");
+			goto done;
+		    }
+		    cprintf(cbr, "XML node %s/%s has no corresponding yang specification (Invalid XML or wrong Yang spec?", xml_name(x1), x1cname);
+		    if ((*reason = strdup(cbuf_get(cbr))) == NULL){
 			clicon_err(OE_UNIX, errno, "strdup");
 			goto done;
 		    }
+		}
 		break;
 	    }
 	    /* See if there is a corresponding node in the base tree */
@@ -1772,6 +1780,8 @@ xml_merge1(cxobj              *x0,
  ok:
     retval = 0;
  done:
+    if (cbr)
+	cbuf_free(cbr);
     return retval;
 }
 
@@ -1797,6 +1807,7 @@ xml_merge(cxobj     *x0,
     cxobj     *x0c; /* base child */
     cxobj     *x1c; /* mod child */
     yang_stmt *yc;
+    cbuf      *cbr = NULL; /* Reason buffer */
 
     /* Loop through children of the modification tree */
     x1c = NULL;
@@ -1804,10 +1815,17 @@ xml_merge(cxobj     *x0,
 	x1cname = xml_name(x1c);
 	/* Get yang spec of the child */
 	if ((yc = yang_find_topnode(yspec, x1cname, YC_DATANODE)) == NULL){
-	    if (reason && (*reason = strdup("XML node has no corresponding yang specification (Invalid XML or wrong Yang spec?")) == NULL){
+	    if (reason){
+		if ((cbr = cbuf_new()) == NULL){
+		    clicon_err(OE_XML, errno, "cbuf_new");
+		    goto done;
+		}
+		cprintf(cbr, "XML node %s/%s has no corresponding yang specification (Invalid XML or wrong Yang spec?", xml_name(x1), x1cname);
+		if ((*reason = strdup(cbuf_get(cbr))) == NULL){
 		    clicon_err(OE_UNIX, errno, "strdup");
 		    goto done;
 		}
+	    }
 	    break;
 	}
 	/* See if there is a corresponding node in the base tree */
@@ -1820,6 +1838,8 @@ xml_merge(cxobj     *x0,
     }
     retval = 0; /* OK */
  done:
+    if (cbr)
+	cbuf_free(cbr);
     return retval;
 }