fat32: update the code because the author seemed to fix the bugs in a282d4b92fc0ce6bc6dfd08111791b984f6834e4

include/fat.h

@@ -8,6 +8,7 @@
 #include <stdbool.h>
 #include <stdint.h>
 //#include <stdio.h>
+#include "../include/stdio.h"
 #include <stdarg.h>
 
 //------------------------------------------------------------------------------
@@ -74,7 +75,7 @@ typedef struct fat_t
   uint32_t sect_per_clust;
   uint32_t clust_cnt;
   uint32_t info_sect;
-  uint32_t fat_sect;
+  uint32_t fat_sect[2];
   uint32_t data_sect;  
   uint32_t root_sect;
 

src/fat.c

@@ -2,11 +2,8 @@
 // Copyright (c) 2025, Bjørn Brodtkorb. All rights reserved.
 
 //#include <string.h>
-#include "../include/fat.h"
-#include "../include/stdio.h"
 #include "../include/string.h"
-
+#include "../include/fat.h"
-#define NULL 0
 
 //------------------------------------------------------------------------------
 #define LIMIT(a, b) ((a) < (b) ? (a) : (b))
@@ -444,6 +441,7 @@ static fat_t* find_fat_volume(const char* path, int len)
     if (len == it->pathlen && 0 == memcmp(path, it->path, len))
       return it;
   }
+
   return NULL;
 }
 
@@ -559,7 +557,8 @@ static uint32_t clust_to_sect(fat_t* fat, uint32_t clust)
 //------------------------------------------------------------------------------
 static int get_fat(fat_t* fat, uint32_t clust, uint32_t* res)
 {
-  uint32_t sect = fat->fat_sect + clust / 128;
+  // Assume first FAT is correct
+  uint32_t sect = fat->fat_sect[0] + clust / 128;
   uint32_t off = (clust % 128) << 2;
 
   int err = move_win(fat, sect);
@@ -573,9 +572,9 @@ static int get_fat(fat_t* fat, uint32_t clust, uint32_t* res)
 }
 
 //------------------------------------------------------------------------------
-static int put_fat(fat_t* fat, uint32_t clust, uint32_t val)
+static int put_fat_in(fat_t* fat, int idx, uint32_t clust, uint32_t val)
 {
-  uint32_t sect = fat->fat_sect + clust / 128;
+  uint32_t sect = fat->fat_sect[idx] + clust / 128;
   uint32_t off = 4 * (clust % 128);
 
   int err = move_win(fat, sect);
@@ -590,6 +589,16 @@ static int put_fat(fat_t* fat, uint32_t clust, uint32_t val)
   return FAT_ERR_NONE;
 }
 
+//------------------------------------------------------------------------------
+static int put_fat(fat_t* fat, uint32_t clust, uint32_t val)
+{
+  int err = put_fat_in(fat, 0, clust, val);
+  if (err)
+    return err;
+  
+  return put_fat_in(fat, 1, clust, val);
+}
+
 //------------------------------------------------------------------------------
 static int get_clust_status(fat_t* fat, uint32_t clust)
 {
@@ -643,7 +652,7 @@ static int clust_chain_remove(fat_t* fat, uint32_t clust)
     if (err)
       return err;
     
-    fat->info_cnt--;
+    fat->info_cnt++;
     clust = next;
 
     if (status & CLUST_LAST)
@@ -942,7 +951,7 @@ static int load_lfn_name(fat_t* fat, dir_t* dir)
 }
 
 //------------------------------------------------------------------------------
-static int dir_search(fat_t* fat, dir_t* dir, const char* name, int len)
+static int dir_search(fat_t* fat, dir_t* dir, const char* name, int len, dir_t* start)
 {
   dir_rewind(fat, dir);
 
@@ -959,8 +968,15 @@ static int dir_search(fat_t* fat, dir_t* dir, const char* name, int len)
 
     if (!dir_ent_is_free(ent))
     {
+      if (start)
+      {
+        start->sect = dir->sect;
+        start->idx = dir->idx;
+      }
+
       if (dir_ent_is_lfn(ent))
       {
+
         err = load_lfn_name(fat, dir);
         if (err)
           return err;
@@ -1007,9 +1023,11 @@ static int follow_path(dir_t* dir, const char** path)
     len = subpath_len(str);
     if (len == 0)
       return FAT_ERR_PATH;
+    
     fat_t* fat = find_fat_volume(str, len);
     if (!fat)
       return FAT_ERR_PATH;
+    
     str += len;
 
     dir->fat = fat;
@@ -1037,7 +1055,7 @@ static int follow_path(dir_t* dir, const char** path)
     if (len == 0)
       return FAT_ERR_NONE;
 
-    err = dir_search(fat, dir, str, len);
+    err = dir_search(fat, dir, str, len, NULL);
     if (err)
       return err;
       
@@ -1184,8 +1202,10 @@ static int get_mbr_partition(fat_t* fat, mbr_part_t* part, int part_num)
   int err = move_win(fat, 0);
   if (err)
     return err;
+
   if (fat->win[510] != 0x55 || fat->win[511] != 0xaa)
     return FAT_ERR_NOFAT;
+
   *part = ((mbr_part_t*)(fat->win + 446))[part_num];
   return FAT_ERR_NONE;
 }
@@ -1238,8 +1258,9 @@ int fat_mount(disk_ops_t* ops, int part_num, fat_t* fat, const char* path)
   fat->sect_per_clust = bpb->sect_per_clust;
   fat->clust_cnt = bpb->sect_per_fat_32 * 128;
   fat->info_sect = part.lba + bpb->info_sect;
-  fat->fat_sect  = part.lba + bpb->res_sect_cnt;
+  fat->fat_sect[0] = part.lba + bpb->res_sect_cnt;
-  fat->data_sect = fat->fat_sect + bpb->fat_cnt * bpb->sect_per_fat_32;
+  fat->fat_sect[1] = fat->fat_sect[0] + bpb->sect_per_fat_32;
+  fat->data_sect = fat->fat_sect[0] + bpb->fat_cnt * bpb->sect_per_fat_32;
   fat->root_sect = clust_to_sect(fat, bpb->root_cluster);
 
   err = move_win(fat, fat->info_sect);
@@ -1345,7 +1366,7 @@ int fat_fopen(file_t* file, const char* path, const char* mode)
   if (len == 0 || path[len])
     return FAT_ERR_PATH;
 
-  err = dir_search(fat, dir, path, len);
+  err = dir_search(fat, dir, path, len, NULL);
 
   if (err == FAT_ERR_EOF)
   {
@@ -1640,8 +1661,9 @@ int fat_unlink(const char* path)
     return FAT_ERR_PATH;
 
   fat_t* fat = dir.fat;
+  dir_t sdir = dir;
 
-  err = dir_search(fat, &dir, path, len);
+  err = dir_search(fat, &dir, path, len, &sdir);
   if (err)
     return err;
   
@@ -1651,9 +1673,24 @@ int fat_unlink(const char* path)
   if (err)
     return err;
 
+  for (;;)
+  {
+    err = move_win(fat, sdir.sect);
+    if (err)
+      return err;
+
+    dir_ent_t* ent = (dir_ent_t*)(fat->win + sdir.idx);
     ent->name[0] = SFN_FREE;
     fat->win_dirty = true;
 
+    if (sdir.sect == dir.sect && sdir.idx == dir.idx)
+      break;
+    
+    err = dir_next(fat, &sdir);
+    if (err)
+      return err;
+  }
+
   return sync_fat(fat);
 }
 
@@ -1671,6 +1708,10 @@ int fat_mkdir(const char* path)
   if (len == 0 || path[len])
     return FAT_ERR_PATH;
 
+  uint32_t prev = dir.first_clust;
+  if (prev == 2) // Old cluster is the root directory
+    prev = 0;
+
   // Create a new directory
   uint32_t new;
   err = clust_chain_create(fat, &new);
@@ -1704,8 +1745,8 @@ int fat_mkdir(const char* path)
 
   memcpy(ent + 1, ent, sizeof(dir_ent_t));
   ent[1].name[1] = '.';
-  ent[1].clust_hi = dir.first_clust >> 16;
+  ent[1].clust_hi = prev >> 16;
-  ent[1].clust_lo = dir.first_clust & 0xffff;
+  ent[1].clust_lo = prev & 0xffff;
 
   err = dir_register(fat, &dir, path, len, FAT_ATTR_DIR, new);
   if (err)