diff --git a/daemon/control_ng_flags_parser.c b/daemon/control_ng_flags_parser.c
index 0ce9ec7d2..2a2c2e65a 100644
--- a/daemon/control_ng_flags_parser.c
+++ b/daemon/control_ng_flags_parser.c
@@ -73,31 +73,8 @@ static bool get_key_val(str * key, str * val, str *in_out)
 	return true;
 }
 
-static inline int str_eq(const str *p, const char *q)
-{
-	int l = strlen(q);
-	if(p->len != l)
-		return 0;
-	if(memcmp(p->s, q, l))
-		return 0;
-	return 1;
-}
-
-static inline int str_prefix(const str *p, const char *q, str *out)
-{
-	int l = strlen(q);
-	if(p->len < l)
-		return 0;
-	if(memcmp(p->s, q, l))
-		return 0;
-	*out = *p;
-	out->s += l;
-	out->len -= l;
-	return 1;
-}
-
 /* handle either "foo-bar" or "foo=bar" from flags */
-static int str_key_val_prefix(const str * p, const char * q,
+static bool str_key_val_prefix(const str * p, const char * q,
 		const str * v, str * out)
 {
 	if(str_eq(p, q)) {
@@ -105,17 +82,18 @@ static int str_key_val_prefix(const str * p, const char * q,
 			return 0;
 
 		*out = *v;
-		return 1;
+		return true;
 	}
-	if(!str_prefix(p, q, out))
-		return 0;
+	*out = *p;
+	if (str_shift_cmp(out, q))
+		return false;
 	if(out->len < 2)
-		return 0;
+		return false;
 	if(*out->s != '-')
-		return 0;
+		return false;
 	out->s++;
 	out->len--;
-	return 1;
+	return true;
 }
 
 /**
diff --git a/lib/str.h b/lib/str.h
index e92f3114d..3e98cf868 100644
--- a/lib/str.h
+++ b/lib/str.h
@@ -68,6 +68,10 @@ __attribute__((nonnull(1, 2)))
 ACCESS(read_only, 1)
 ACCESS(read_only, 2)
 INLINE int str_cmp(const str *a, const char *b);
+__attribute__((nonnull(1, 2)))
+ACCESS(read_only, 1)
+ACCESS(read_only, 2)
+INLINE bool str_eq(const str *a, const char *b);
 /* compares a str to a non-null-terminated string */
 __attribute__((nonnull(1, 2)))
 ACCESS(read_only, 1)
@@ -255,6 +259,9 @@ INLINE int str_cmp_len(const str *a, const char *b, size_t l) {
 INLINE int str_cmp(const str *a, const char *b) {
 	return str_cmp_len(a, b, strlen(b));
 }
+INLINE bool str_eq(const str *a, const char *b) {
+	return str_cmp(a, b) == 0;
+}
 INLINE int str_cmp_str(const str *a, const str *b) {
 	if (a->len < b->len)
 		return -1;