diff --git a/src/util.c b/src/util.c
index e2ada556..ca543502 100644
--- a/src/util.c
+++ b/src/util.c
@@ -349,7 +349,12 @@ int string2ll(const char *s, size_t slen, long long *value) {
     if (plen == slen)
         return 0;
 
-    /* Handle negative integers. */
+    /* Special case: first and only digit is 0. */
+    if (slen == 1 && p[0] == '0') {
+        if (value != NULL) *value = 0;
+        return 1;
+    }
+
     if (p[0] == '-') {
         negative = 1;
         p++; plen++;
@@ -364,7 +369,7 @@ int string2ll(const char *s, size_t slen, long long *value) {
         v = p[0]-'0';
         p++; plen++;
     } else if (p[0] == '0' && slen == 1) {
-        if (value != NULL) *value = 0;
+        *value = 0;
         return 1;
     } else {
         return 0;