add non-failing close() variant

util.c

@@ -97,6 +97,14 @@ int close_nointr(int fd) {
         }
 }
 
+void close_nointr_nofail(int fd) {
+
+        /* like close_nointr() but cannot fail, and guarantees errno
+         * is unchanged */
+
+        assert_se(close_nointr(fd) == 0);
+}
+
 int parse_boolean(const char *v) {
         assert(v);
 

util.h

@@ -61,6 +61,7 @@ bool endswith(const char *s, const char *postfix);
 bool startswith(const char *s, const char *prefix);
 
 int close_nointr(int fd);
+void close_nointr_nofail(int fd);
 
 int parse_boolean(const char *v);