Merge pull request #886 from BrianPugh/macro-sanity-check

Add value-range checks for user-definable macros at compile-time

lfs.c

@@ -4108,6 +4108,21 @@ static int lfs_rawremoveattr(lfs_t *lfs, const char *path, uint8_t type) {
 
 
 /// Filesystem operations ///
+
+// compile time checks, see lfs.h for why these limits exist
+#if LFS_NAME_MAX > 1022
+#error "Invalid LFS_NAME_MAX, must be <= 1022"
+#endif
+
+#if LFS_FILE_MAX > 2147483647
+#error "Invalid LFS_FILE_MAX, must be <= 2147483647"
+#endif
+
+#if LFS_ATTR_MAX > 1022
+#error "Invalid LFS_ATTR_MAX, must be <= 1022"
+#endif
+
+// common filesystem initialization
 static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
     lfs->cfg = cfg;
     lfs->block_count = cfg->block_count;  // May be 0

lfs.h

@@ -52,10 +52,8 @@ typedef uint32_t lfs_block_t;
 #endif
 
 // Maximum size of a file in bytes, may be redefined to limit to support other
-// drivers. Limited on disk to <= 4294967296. However, above 2147483647 the
-// functions lfs_file_seek, lfs_file_size, and lfs_file_tell will return
-// incorrect values due to using signed integers. Stored in superblock and
-// must be respected by other littlefs drivers.
+// drivers. Limited on disk to <= 2147483647. Stored in superblock and must be
+// respected by other littlefs drivers.
 #ifndef LFS_FILE_MAX
 #define LFS_FILE_MAX 2147483647
 #endif