Create BIS storage interface.

Takes care of retrieving a FsStorage object for any FAT eMMC BIS partition, mounting it via FatFs and creating a virtual devoptab device that can be used to carry out FS operations. All write operations have been stubbed, disabled or ifdef'd out of the code.

Other changes include:

* cert: update code to use the new BIS storage interface.

* defines: remove BIS_SYSTEM_PARTITION_MOUNT_NAME macro.

* devoptab: slightly improve macros.
* devoptab: add operation table for FatFs devices.
* devoptab: add rodev_fstat().
* devoptab: add devoptabMountFatFsDevice().

* fatfs: update diskio code to use the new BIS storage interface.
* fatfs: update configuration.

* save: update code to use regular C I/O calls instead of FatFs calls.

* tik: update code to use the new BIS storage interface.

* utils: remove eMMC BIS System partition (un)mount code.

include/core/bis_storage.h

@@ -0,0 +1,54 @@
+/*
+ * bis_storage.h
+ *
+ * Copyright (c) 2020-2024, DarkMatterCore <[email protected]>.
+ *
+ * This file is part of nxdumptool (https://github.com/DarkMatterCore/nxdumptool).
+ *
+ * nxdumptool is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * nxdumptool is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+
+#ifndef __BIS_STORAGE_H__
+#define __BIS_STORAGE_H__
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/// Mounts an eMMC BIS partition using its ID and provides a pointer to a string that holds its mount name, which can be used to carry out FS operations.
+/// Only eMMC BIS partition IDs `CalibrationFile` (28) through `System` (31) are supported.
+bool bisStorageMountPartition(u8 bis_partition_id, const char **out_mount_name);
+
+/// Unmounts a previously mounted eMMC BIS partition.
+/// Only eMMC BIS partition IDs `CalibrationFile` (28) through `System` (31) are supported.
+void bisStorageUnmountPartition(u8 bis_partition_id);
+
+/// Unmounts all previously mounted eMMC BIS partitions.
+void bisStorageUnmountAllPartitions(void);
+
+/// Returns a pointer to a FsStorage object that matches the provided FatFs drive number, or NULL if it hasn't been mounted.
+/// Only used by FatFs's diskio operations.
+FsStorage *bisStorageGetFsStorageByFatFsDriveNumber(u8 drive_number);
+
+/// (Un)locks the BIS storage mutex. Can be used to block other threads and prevent them from altering the internal status of this interface.
+/// Use with caution.
+void bisStorageControlMutex(bool lock);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __BIS_STORAGE_H__ */

include/core/devoptab/nxdt_devoptab.h

@@ -27,54 +27,56 @@
 #include "../pfs.h"
 #include "../hfs.h"
 #include "../romfs.h"
+#include "../fatfs/ff.h"
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
-#define DEVOPTAB_MOUNT_NAME_LENGTH                  32  // Including NULL terminator.
+#define DEVOPTAB_MOUNT_NAME_LENGTH      32  // Including NULL terminator.
 
-#define DEVOPTAB_DECL_ERROR_STATE                   int _errno = 0
-#define DEVOPTAB_DECL_DEV_CTX                       DevoptabDeviceContext *dev_ctx = (DevoptabDeviceContext*)r->deviceData
-#define DEVOPTAB_DECL_FS_CTX(type)                  type *fs_ctx = (type*)dev_ctx->fs_ctx
-#define DEVOPTAB_DECL_FILE_STATE(type)              type *file = (type*)fd
-#define DEVOPTAB_DECL_DIR_STATE(type)               type *dir = (type*)dirState->dirStruct
+#define DEVOPTAB_INIT_ERROR_STATE       r->_errno = 0
+#define DEVOPTAB_DECL_DEV_CTX           DevoptabDeviceContext *dev_ctx = (DevoptabDeviceContext*)r->deviceData
+#define DEVOPTAB_DECL_FS_CTX(type)      type *fs_ctx = (type*)dev_ctx->fs_ctx
+#define DEVOPTAB_DECL_FILE_STATE(type)  type *file = (type*)fd
+#define DEVOPTAB_DECL_DIR_STATE(type)   type *dir = (type*)dirState->dirStruct
 
-#define DEVOPTAB_SET_ERROR(x)                       r->_errno = _errno = (x)
-#define DEVOPTAB_IS_ERROR_SET                       (_errno != 0)
+#define DEVOPTAB_SET_ERROR(x)           r->_errno = (x)
+#define DEVOPTAB_IS_ERROR_SET           (r->_errno != 0)
 
-#define DEVOPTAB_EXIT                               goto end
-#define DEVOPTAB_SET_ERROR_AND_EXIT(x)              \
+#define DEVOPTAB_EXIT                   goto end
+#define DEVOPTAB_SET_ERROR_AND_EXIT(x)  \
 do { \
     DEVOPTAB_SET_ERROR(x); \
     DEVOPTAB_EXIT; \
 } while(0)
 
-#define DEVOPTAB_RETURN_INT(x)                      return (DEVOPTAB_IS_ERROR_SET ? -1 : (x))
-#define DEVOPTAB_RETURN_PTR(x)                      return (DEVOPTAB_IS_ERROR_SET ? NULL : (x))
-#define DEVOPTAB_RETURN_BOOL                        return (DEVOPTAB_IS_ERROR_SET ? false : true)
-#define DEVOPTAB_RETURN_UNSUPPORTED_OP              r->_errno = ENOSYS; \
-                                                    return -1;
+#define DEVOPTAB_RETURN_INT(x)          return (DEVOPTAB_IS_ERROR_SET ? -1 : (x))
+#define DEVOPTAB_RETURN_PTR(x)          return (DEVOPTAB_IS_ERROR_SET ? NULL : (x))
+#define DEVOPTAB_RETURN_BOOL            return (DEVOPTAB_IS_ERROR_SET ? false : true)
+#define DEVOPTAB_RETURN_UNSUPPORTED_OP  r->_errno = ENOSYS; \
+                                        return -1
 
-#define DEVOPTAB_INIT_VARS(type)                    devoptabControlMutex(true); \
-                                                    DEVOPTAB_DECL_ERROR_STATE; \
-                                                    DEVOPTAB_DECL_DEV_CTX; \
-                                                    if (!dev_ctx->initialized) DEVOPTAB_SET_ERROR_AND_EXIT(ENODEV);
+#define DEVOPTAB_INIT_VARS              devoptabControlMutex(true); \
+                                        DEVOPTAB_INIT_ERROR_STATE; \
+                                        DEVOPTAB_DECL_DEV_CTX; \
+                                        if (!dev_ctx->initialized) DEVOPTAB_SET_ERROR_AND_EXIT(ENODEV)
 
-#define DEVOPTAB_INIT_FILE_VARS(fs_type, file_type) DEVOPTAB_INIT_VARS(fs_type); \
-                                                    DEVOPTAB_DECL_FILE_STATE(file_type)
+#define DEVOPTAB_INIT_FILE_VARS(type)   DEVOPTAB_INIT_VARS; \
+                                        DEVOPTAB_DECL_FILE_STATE(type)
 
-#define DEVOPTAB_INIT_DIR_VARS(fs_type, dir_type)   DEVOPTAB_INIT_VARS(fs_type); \
-                                                    DEVOPTAB_DECL_DIR_STATE(dir_type)
+#define DEVOPTAB_INIT_DIR_VARS(type)    DEVOPTAB_INIT_VARS; \
+                                        if (!dirState) DEVOPTAB_SET_ERROR_AND_EXIT(EINVAL); \
+                                        DEVOPTAB_DECL_DIR_STATE(type)
 
-#define DEVOPTAB_DEINIT_VARS                        devoptabControlMutex(false)
+#define DEVOPTAB_DEINIT_VARS            devoptabControlMutex(false)
 
 typedef struct {
     bool initialized;                       ///< Device initialization flag.
     char name[DEVOPTAB_MOUNT_NAME_LENGTH];  ///< Mount name string, without a trailing colon (:).
     time_t mount_time;                      ///< Mount time.
     devoptab_t device;                      ///< Devoptab virtual device interface. Provides a way to use libcstd I/O calls on the mounted filesystem.
-    void *fs_ctx;                           ///< Pointer to actual type-specific filesystem context (PartitionFileSystemContext, HashFileSystemContext, RomFileSystemContext).
+    void *fs_ctx;                           ///< Pointer to actual type-specific filesystem context (PartitionFileSystemContext, HashFileSystemContext, RomFileSystemContext, FATFS).
 } DevoptabDeviceContext;
 
 /// Mounts a virtual Partition FS device using the provided Partition FS context and a mount name.
@@ -86,6 +88,9 @@ bool devoptabMountHashFileSystemDevice(HashFileSystemContext *hfs_ctx, const cha
 /// Mounts a virtual RomFS device using the provided RomFS context and a mount name.
 bool devoptabMountRomFileSystemDevice(RomFileSystemContext *romfs_ctx, const char *name);
 
+/// Mounts a virtual FatFs device using the provided FATFS object and a mount name.
+bool devoptabMountFatFsDevice(FATFS *fatfs, const char *name);
+
 /// Unmounts a previously mounted virtual device.
 void devoptabUnmountDevice(const char *name);
 

include/core/devoptab/ro_dev.h

@@ -32,6 +32,7 @@ extern "C" {
 /* We don't provide support for relative directories, so chdir is discarded as well. */
 
 ssize_t rodev_write(struct _reent *r, void *fd, const char *ptr, size_t len);
+int     rodev_fstat(struct _reent *r, void *fd, struct stat *st);
 int     rodev_link(struct _reent *r, const char *existing, const char *newLink);
 int     rodev_unlink(struct _reent *r, const char *name);
 int     rodev_chdir(struct _reent *r, const char *name);

include/core/fatfs/ffconf.h

@@ -166,12 +166,11 @@
 / Drive/Volume Configurations
 /---------------------------------------------------------------------------*/
 
-#define FF_VOLUMES		1
+#define FF_VOLUMES		4
 /* Number of volumes (logical drives) to be used. (1-10) */
 
 
 #define FF_STR_VOLUME_ID	1
-#define FF_VOLUME_STRS		"sys"
 /* FF_STR_VOLUME_ID switches support for volume ID in arbitrary strings.
 /  When FF_STR_VOLUME_ID is set to 1 or 2, arbitrary strings can be used as drive
 /  number in the path name. FF_VOLUME_STRS defines the volume ID strings for each

include/core/nxdt_utils.h

@@ -114,9 +114,6 @@ bool utilsIsTerraUnit(void);
 /// Returns true if the application is running under applet mode.
 bool utilsIsAppletMode(void);
 
-/// Returns a pointer to the FsStorage object for the eMMC BIS System partition.
-FsStorage *utilsGetEmmcBisSystemPartitionStorage(void);
-
 /// Blocks HOME button presses, disables screen dimming and auto sleep and overclocks system CPU/MEM.
 /// Must be called before starting long-running processes.
 /// If state is set to false, regular system behavior is restored.

include/core/save.h

@@ -25,8 +25,6 @@
 #ifndef __SAVE_H__
 #define __SAVE_H__
 
-#include "fatfs/ff.h"
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -45,7 +43,7 @@ extern "C" {
 #define MAGIC_RMAP                      0x50414D52
 #define MAGIC_IVFC                      0x43465649
 
-#define ACTION_VERIFY                   (1<<2)
+#define ACTION_VERIFY                   (1 << 2)
 
 typedef enum {
     VALIDITY_UNCHECKED = 0,
@@ -232,7 +230,7 @@ typedef struct {
     enum base_storage_type type;
     u64 base_storage_offset;
     duplex_storage_ctx_t *duplex;
-    FIL *file;
+    FILE *file;
 } remap_storage_ctx_t;
 
 typedef struct {
@@ -333,7 +331,7 @@ typedef struct {
     u32 block_size;
     u64 journal_data_offset;
     u64 _length;
-    FIL *file;
+    FILE *file;
 } journal_storage_ctx_t;
 
 typedef struct {
@@ -470,9 +468,9 @@ typedef struct {
 
 struct save_ctx_t {
     save_header_t header;
-    FIL *file;
+    FILE *file;
     struct {
-        FIL *file;
+        FILE *file;
         u32 action;
     } tool_ctx;
     validity_t header_cmac_validity;
@@ -549,7 +547,7 @@ bool save_hierarchical_file_table_find_path_recursive(hierarchical_save_file_tab
 bool save_hierarchical_file_table_get_file_entry_by_path(hierarchical_save_file_table_ctx_t *ctx, const char *path, save_fs_list_entry_t *entry);
 
 save_ctx_t *save_open_savefile(const char *path, u32 action);
-void save_close_savefile(save_ctx_t *ctx);
+void save_close_savefile(save_ctx_t **ctx);
 bool save_get_fat_storage_from_file_entry_by_path(save_ctx_t *ctx, const char *path, allocation_table_storage_ctx_t *out_fat_storage, u64 *out_file_entry_size);
 
 #ifdef __cplusplus

include/defines.h

@@ -104,8 +104,6 @@
 #define LOG_BUF_SIZE                    0x400000                                                        /* 4 MiB. */
 #define LOG_FORCE_FLUSH                 0                                                               /* Forces a log buffer flush each time the logfile is written to. */
 
-#define BIS_SYSTEM_PARTITION_MOUNT_NAME "sys:"
-
 /// Reference: https://docs.microsoft.com/en-us/windows/win32/fileio/filesystem-functionality-comparison#limits.
 /// Reference: https://en.wikipedia.org/wiki/Comparison_of_file_systems#Limits.
 /// Most modern filesystems use a 255-byte limit instead of 255-character/codepoint limit, so that's what we're gonna use.