From: Tom Hromatka <tom.hromatka@oracle.com>
Date: Mon, 8 Feb 2021 23:05:24 +0000 (-0700)
Subject: wrapper.c: Add support for empty values in cgroup_add_value_string()
X-Git-Tag: v2.0.rc1~10^2~1
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=e7ac3fd8f1eaf515e70b67effd2af9b372e86e0b;p=thirdparty%2Flibcgroup.git

wrapper.c: Add support for empty values in cgroup_add_value_string()

cgroup_add_value_string() is the fundamental building block
for adding a name/value pair to a cgroup_controller struct.
Add support for a NULL value field.

Currently it only supports adding a valid value, but in a
subsequent commit, cgget will utilize this function to build
up a hierarchy of cgroups, controllers, and setting names.
The values are NULL at the time the struct are populated and
will be read from sysfs at a later time.

Signed-off-by: Tom Hromatka <tom.hromatka@oracle.com>
---

diff --git a/src/wrapper.c b/src/wrapper.c
index b7932545..35f5dbd8 100644
--- a/src/wrapper.c
+++ b/src/wrapper.c
@@ -195,18 +195,22 @@ int cgroup_add_value_string(struct cgroup_controller *controller,
 	if (!cntl_value)
 		return ECGCONTROLLERCREATEFAILED;
 
-	if (strlen(value) >= sizeof(cntl_value->value)) {
-		fprintf(stderr, "value exceeds the maximum of %d characters\n",
-			sizeof(cntl_value->value) - 1);
-		free(cntl_value);
-		return ECGCONFIGPARSEFAIL;
-	}
-
 	strncpy(cntl_value->name, name, sizeof(cntl_value->name));
 	cntl_value->name[sizeof(cntl_value->name)-1] = '\0';
-	strncpy(cntl_value->value, value, sizeof(cntl_value->value));
-	cntl_value->value[sizeof(cntl_value->value)-1] = '\0';
-	cntl_value->dirty = true;
+
+	if (value) {
+		if (strlen(value) >= sizeof(cntl_value->value)) {
+			fprintf(stderr, "value exceeds the maximum of %d characters\n",
+				sizeof(cntl_value->value) - 1);
+			free(cntl_value);
+			return ECGCONFIGPARSEFAIL;
+		}
+
+		strncpy(cntl_value->value, value, sizeof(cntl_value->value));
+		cntl_value->value[sizeof(cntl_value->value)-1] = '\0';
+		cntl_value->dirty = true;
+	}
+
 	controller->values[controller->index] = cntl_value;
 	controller->index++;