From 469c863c18b99bf17470e1c066252d43bfaa3e14 Mon Sep 17 00:00:00 2001
From: Dong Wang <wangdong115@foxmail.com>
Date: Tue, 10 Dec 2024 00:17:43 +0800
Subject: [PATCH] Assert on NULL IO function

---
 lfs.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/lfs.c b/lfs.c
index 9e7fff7f..e92381ae 100644
--- a/lfs.c
+++ b/lfs.c
@@ -4217,6 +4217,14 @@ static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
     // which littlefs currently does not support
     LFS_ASSERT((bool)0x80000000);
 
+    // check that the required io functions are provided
+    LFS_ASSERT(lfs->cfg->read != NULL);
+#ifndef LFS_READONLY
+    LFS_ASSERT(lfs->cfg->prog != NULL);
+    LFS_ASSERT(lfs->cfg->erase != NULL);
+    LFS_ASSERT(lfs->cfg->sync != NULL);
+#endif
+
     // validate that the lfs-cfg sizes were initiated properly before
     // performing any arithmetic logics with them
     LFS_ASSERT(lfs->cfg->read_size != 0);