From 125b276af02d373153de6f4277d22e9d215980ec Mon Sep 17 00:00:00 2001
From: Scott Shawcroft <scott@tannewt.org>
Date: Thu, 4 Aug 2022 16:06:27 -0700
Subject: [PATCH] Get CIRCUITPY FATFS directly.

Otherwise, you may actually get a non-root filesystem.

Fixes #6575
---
 ports/espressif/boards/mixgo_ce_serial/board.c |  3 ++-
 shared-module/dotenv/__init__.c                |  3 ++-
 supervisor/filesystem.h                        |  2 ++
 supervisor/shared/bluetooth/file_transfer.c    | 13 +++++++------
 supervisor/shared/filesystem.c                 | 13 +++++++++++--
 supervisor/shared/web_workflow/web_workflow.c  |  3 ++-
 6 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/ports/espressif/boards/mixgo_ce_serial/board.c b/ports/espressif/boards/mixgo_ce_serial/board.c
index e07fe5cfd7..32cb1749ca 100644
--- a/ports/espressif/boards/mixgo_ce_serial/board.c
+++ b/ports/espressif/boards/mixgo_ce_serial/board.c
@@ -31,6 +31,7 @@
 #include "lib/oofatfs/ff.h"
 #include "extmod/vfs_fat.h"
 #include "py/mpstate.h"
+#include "supervisor/filesystem.h"
 
 void board_init(void) {
     // Debug UART
@@ -41,7 +42,7 @@ void board_init(void) {
 
     mp_import_stat_t stat_b = mp_import_stat("boot.py");
     if (stat_b != MP_IMPORT_STAT_FILE) {
-        FATFS *fatfs = &((fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj)->fatfs;
+        FATFS *fatfs = filesystem_circuitpy();
         FIL fs;
         UINT char_written = 0;
         const byte buffer[] = "#Serial port upload mode\nimport storage\nstorage.remount(\"/\", False)\nstorage.disable_usb_drive()\n";
diff --git a/shared-module/dotenv/__init__.c b/shared-module/dotenv/__init__.c
index bd1973366d..f17d684e12 100644
--- a/shared-module/dotenv/__init__.c
+++ b/shared-module/dotenv/__init__.c
@@ -32,6 +32,7 @@
 #include "extmod/vfs_fat.h"
 #include "py/mpstate.h"
 #include "py/objstr.h"
+#include "supervisor/filesystem.h"
 
 STATIC uint8_t consume_spaces(FIL *active_file) {
     uint8_t character = ' ';
@@ -188,7 +189,7 @@ STATIC mp_int_t read_value(FIL *active_file, char *value, size_t value_len) {
 
 mp_int_t dotenv_get_key(const char *path, const char *key, char *value, mp_int_t value_len) {
     FIL active_file;
-    FATFS *fs = &((fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj)->fatfs;
+    FATFS *fs = filesystem_circuitpy();
     FRESULT result = f_open(fs, &active_file, path, FA_READ);
     if (result != FR_OK) {
         return -1;
diff --git a/supervisor/filesystem.h b/supervisor/filesystem.h
index 6f4faf0b82..3954291513 100644
--- a/supervisor/filesystem.h
+++ b/supervisor/filesystem.h
@@ -45,4 +45,6 @@ void filesystem_set_concurrent_write_protection(fs_user_mount_t *vfs, bool concu
 bool filesystem_is_writable_by_python(fs_user_mount_t *vfs);
 bool filesystem_is_writable_by_usb(fs_user_mount_t *vfs);
 
+FATFS *filesystem_circuitpy(void);
+
 #endif  // MICROPY_INCLUDED_SUPERVISOR_FILESYSTEM_H
diff --git a/supervisor/shared/bluetooth/file_transfer.c b/supervisor/shared/bluetooth/file_transfer.c
index a6a2f8062a..216cf3d567 100644
--- a/supervisor/shared/bluetooth/file_transfer.c
+++ b/supervisor/shared/bluetooth/file_transfer.c
@@ -43,6 +43,7 @@
 #include "common-hal/_bleio/__init__.h"
 
 #include "supervisor/fatfs_port.h"
+#include "supervisor/filesystem.h"
 #include "supervisor/shared/reload.h"
 #include "supervisor/shared/bluetooth/file_transfer.h"
 #include "supervisor/shared/bluetooth/file_transfer_protocol.h"
@@ -172,7 +173,7 @@ STATIC uint8_t _process_read(const uint8_t *raw_buf, size_t command_len) {
     char *path = (char *)((uint8_t *)command) + header_size;
     path[command->path_length] = '\0';
 
-    FATFS *fs = &((fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj)->fatfs;
+    FATFS *fs = filesystem_circuitpy();
     FRESULT result = f_open(fs, &active_file, path, FA_READ);
     if (result != FR_OK) {
         response.status = STATUS_ERROR;
@@ -289,7 +290,7 @@ STATIC uint8_t _process_write(const uint8_t *raw_buf, size_t command_len) {
         return ANY_COMMAND;
     }
 
-    FATFS *fs = &((fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj)->fatfs;
+    FATFS *fs = filesystem_circuitpy();
     DWORD fattime;
     _truncated_time = truncate_time(command->modification_time, &fattime);
     override_fattime(fattime);
@@ -438,7 +439,7 @@ STATIC uint8_t _process_delete(const uint8_t *raw_buf, size_t command_len) {
     if (command_len < header_size + command->path_length) {
         return THIS_COMMAND;
     }
-    FATFS *fs = &((fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj)->fatfs;
+    FATFS *fs = filesystem_circuitpy();
     char *path = (char *)((uint8_t *)command) + header_size;
     path[command->path_length] = '\0';
     FILINFO file;
@@ -495,7 +496,7 @@ STATIC uint8_t _process_mkdir(const uint8_t *raw_buf, size_t command_len) {
     if (command_len < header_size + command->path_length) {
         return THIS_COMMAND;
     }
-    FATFS *fs = &((fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj)->fatfs;
+    FATFS *fs = filesystem_circuitpy();
     char *path = (char *)command->path;
     _terminate_path(path, command->path_length);
 
@@ -552,7 +553,7 @@ STATIC uint8_t _process_listdir(uint8_t *raw_buf, size_t command_len) {
         return THIS_COMMAND;
     }
 
-    FATFS *fs = &((fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj)->fatfs;
+    FATFS *fs = filesystem_circuitpy();
     char *path = (char *)&command->path;
     _terminate_path(path, command->path_length);
     // mp_printf(&mp_plat_print, "list %s\n", path);
@@ -640,7 +641,7 @@ STATIC uint8_t _process_move(const uint8_t *raw_buf, size_t command_len) {
     if (command_len < header_size + total_path_length) {
         return THIS_COMMAND;
     }
-    FATFS *fs = &((fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj)->fatfs;
+    FATFS *fs = filesystem_circuitpy();
     char *old_path = (char *)command->paths;
     old_path[command->old_path_length] = '\0';
 
diff --git a/supervisor/shared/filesystem.c b/supervisor/shared/filesystem.c
index 820dbe9783..283849adc3 100644
--- a/supervisor/shared/filesystem.c
+++ b/supervisor/shared/filesystem.c
@@ -92,6 +92,9 @@ bool filesystem_init(bool create_allowed, bool force_create) {
     vfs_fat->blockdev.flags = 0;
     supervisor_flash_init_vfs(vfs_fat);
 
+    mp_vfs_mount_t *vfs = &_mp_vfs;
+    vfs->len = 0;
+
     // try to mount the flash
     FRESULT res = f_mount(&vfs_fat->fatfs);
     if ((res == FR_NO_FILESYSTEM && create_allowed) || force_create) {
@@ -140,7 +143,6 @@ bool filesystem_init(bool create_allowed, bool force_create) {
     } else if (res != FR_OK) {
         return false;
     }
-    mp_vfs_mount_t *vfs = &_mp_vfs;
     vfs->str = "/";
     vfs->len = 1;
     vfs->obj = MP_OBJ_FROM_PTR(vfs_fat);
@@ -199,5 +201,12 @@ void filesystem_set_concurrent_write_protection(fs_user_mount_t *vfs, bool concu
 }
 
 bool filesystem_present(void) {
-    return true;
+    return _mp_vfs.len > 0;
+}
+
+FATFS *filesystem_circuitpy(void) {
+    if (!filesystem_present()) {
+        return NULL;
+    }
+    return &_internal_vfs.fatfs;
 }
diff --git a/supervisor/shared/web_workflow/web_workflow.c b/supervisor/shared/web_workflow/web_workflow.c
index 9e8c32d963..dc93aeb0bc 100644
--- a/supervisor/shared/web_workflow/web_workflow.c
+++ b/supervisor/shared/web_workflow/web_workflow.c
@@ -36,6 +36,7 @@
 #include "shared-module/storage/__init__.h"
 #include "shared/timeutils/timeutils.h"
 #include "supervisor/fatfs_port.h"
+#include "supervisor/filesystem.h"
 #include "supervisor/shared/reload.h"
 #include "supervisor/shared/translate/translate.h"
 #include "supervisor/shared/web_workflow/web_workflow.h"
@@ -979,7 +980,7 @@ static bool _reply(socketpool_socket_obj_t *socket, _request *request) {
         } else {
             char *path = request->path + 3;
             size_t pathlen = strlen(path);
-            FATFS *fs = &((fs_user_mount_t *)MP_STATE_VM(vfs_mount_table)->obj)->fatfs;
+            FATFS *fs = filesystem_circuitpy();
             // Trailing / is a directory.
             bool directory = false;
             if (path[pathlen - 1] == '/') {