cfgfile: support empty value

This commit adds support to the cfgfile library for parsing a key=value
line that has no value string specified (e.g., "key=").  This can be used
to override a configuration attribute that has a default value or default
list of values to set it back to an undefined value to disable
functionality.

Signed-off-by: Allain Legacy <allain.legacy@windriver.com>
Acked-by: Cristian Dumitrescu <cristian.dumitrescu@intel.com>

lib/librte_cfgfile/rte_cfgfile.c

@@ -258,13 +258,22 @@ rte_cfgfile_load_with_params(const char *filename, int flags,
 
 			struct rte_cfgfile_section *sect =
 				cfg->sections[curr_section];
-			char *split[2];
-			if (rte_strsplit(buffer, sizeof(buffer), split, 2, '=')
-				!= 2) {
-				printf("Error at line %d - cannot split "
-					"string\n", lineno);
+			int n;
+			char *split[2] = {NULL};
+			n = rte_strsplit(buffer, sizeof(buffer), split, 2, '=');
+			if (flags & CFG_FLAG_EMPTY_VALUES) {
+				if ((n < 1) || (n > 2)) {
+					printf("Error at line %d - cannot split string, n=%d\n",
+					       lineno, n);
 					goto error1;
 				}
+			} else {
+				if (n != 2) {
+					printf("Error at line %d - cannot split string, n=%d\n",
+					       lineno, n);
+					goto error1;
+				}
+			}
 
 			curr_entry++;
 			if (curr_entry == allocated_entries) {
@@ -293,7 +302,7 @@ rte_cfgfile_load_with_params(const char *filename, int flags,
 			snprintf(entry->name, sizeof(entry->name), "%s",
 				split[0]);
 			snprintf(entry->value, sizeof(entry->value), "%s",
-				split[1]);
+				 split[1] ? split[1] : "");
 			_strip(entry->name, strnlen(entry->name,
 				sizeof(entry->name)));
 			_strip(entry->value, strnlen(entry->value,

lib/librte_cfgfile/rte_cfgfile.h

@@ -80,6 +80,12 @@ enum {
 	 * section.
 	 */
 	CFG_FLAG_GLOBAL_SECTION = 1,
+
+	/**
+	 * Indicates that file supports key value entries where the value can
+	 * be zero length (e.g., "key=").
+	 */
+	CFG_FLAG_EMPTY_VALUES = 2,
 };
 /**@} */
 

test/test/test_cfgfile.c

@@ -192,6 +192,35 @@ test_cfgfile_invalid_key_value_pair(void)
 	return 0;
 }
 
+static int
+test_cfgfile_empty_key_value_pair(void)
+{
+	struct rte_cfgfile *cfgfile;
+	const char *value;
+	int ret;
+
+	cfgfile = rte_cfgfile_load(CFG_FILES_ETC "/empty_key_value.ini",
+				   CFG_FLAG_EMPTY_VALUES);
+	TEST_ASSERT_NOT_NULL(cfgfile, "Failed to parse empty_key_value.ini");
+
+	ret = rte_cfgfile_num_sections(cfgfile, NULL, 0);
+	TEST_ASSERT(ret == 1, "Unexpected number of sections: %d", ret);
+
+	ret = rte_cfgfile_has_section(cfgfile, "section1");
+	TEST_ASSERT(ret, "section1 missing");
+
+	ret = rte_cfgfile_section_num_entries(cfgfile, "section1");
+	TEST_ASSERT(ret == 1, "section1 unexpected number of entries: %d", ret);
+
+	value = rte_cfgfile_get_entry(cfgfile, "section1", "key");
+	TEST_ASSERT(strlen(value) == 0, "key unexpected value: %s", value);
+
+	ret = rte_cfgfile_close(cfgfile);
+	TEST_ASSERT_SUCCESS(ret, "Failed to close cfgfile");
+
+	return 0;
+}
+
 static int
 test_cfgfile_missing_section(void)
 {
@@ -272,6 +301,9 @@ test_cfgfile(void)
 	if (test_cfgfile_invalid_key_value_pair())
 		return -1;
 
+	if (test_cfgfile_empty_key_value_pair())
+		return -1;
+
 	if (test_cfgfile_missing_section())
 		return -1;
 

test/test/test_cfgfiles/etc/empty_key_value.ini

@@ -1,3 +1,3 @@
 [section1]
 ; this is section 1
-invalid=
+key=