gistfile1.diff

diff --git ext/socket/socket.c ext/socket/socket.c
index 6b145ac..38c79cd 100644
--- ext/socket/socket.c
+++ ext/socket/socket.c
@@ -1023,17 +1023,25 @@ sock_sysaccept(VALUE sock)
 static VALUE
 sock_gethostname(VALUE obj)
 {
-#ifndef HOST_NAME_MAX
-#  define HOST_NAME_MAX 1024
-#endif
-    char buf[HOST_NAME_MAX+1];
+    size_t namelen = 64;
+    char* buf = malloc(namelen);
 
-    rb_secure(3);
-    if (gethostname(buf, (int)sizeof buf - 1) < 0)
+    while(1) {
+	int rc = gethostname(buf, namelen);
+	if (rc == 0) {
+	    break;
+	}
+	if (errno == ENAMETOOLONG) {
+	    namelen *= 2;
+	    buf = realloc(buf, namelen);
+	    continue;
+	}
 	rb_sys_fail("gethostname(3)");
+    }
 
-    buf[sizeof buf - 1] = '\0';
-    return rb_str_new2(buf);
+    VALUE str = rb_str_new(buf, namelen);
+    free(buf);
+    return str;
 }
 #else
 #ifdef HAVE_UNAME