diff --git a/core/utils.c b/core/utils.c
index c324e145..4aa0391c 100644
--- a/core/utils.c
+++ b/core/utils.c
@@ -4186,7 +4186,8 @@ char *uwsgi_str_to_hex(char *src, size_t slen) {
 	char *ptr = dst;
 	size_t i;
 	for (i = 0; i < slen; i++) {
-		memcpy(ptr, uwsgi_hex_table[(int) src[i]], 2);
+		uint8_t pos = (uint8_t) src[i];
+		memcpy(ptr, uwsgi_hex_table[pos], 2);
 		ptr += 2;
 	}
 	return dst;
diff --git a/core/uwsgi.c b/core/uwsgi.c
index 552c378a..019b136f 100644
--- a/core/uwsgi.c
+++ b/core/uwsgi.c
@@ -1025,6 +1025,12 @@ void config_magic_table_fill(char *filename, char **magic_table) {
 	magic_table['b'] = uwsgi.binary_path;
 	magic_table['p'] = fullname;
 
+	// compute filename hash
+	uint32_t hash = djb33x_hash(magic_table['p'], strlen(magic_table['p']));
+	char *hex = uwsgi_str_to_hex((char *)&hash, 4);
+	magic_table['j'] = uwsgi_concat2n(hex, 8, "", 0);
+	free(hex);
+
 	struct stat st;
 	if (!lstat(fullname, &st)) {
 		magic_table['i'] = uwsgi_num2str(st.st_ino);
@@ -1103,6 +1109,7 @@ reuse:
                 magic_table['N'] = magic_table['n'];
                 magic_table['X'] = magic_table['x'];
                 magic_table['I'] = magic_table['i'];
+                magic_table['J'] = magic_table['j'];
 		uwsgi.magic_table_first_round = 1;
         }