Arrow
Repostiory containing DAPLink source code with Reset Pin workaround for HANI_IOT board.
Upstream: https://github.com/ARMmbed/DAPLink
Diff: source/daplink/drag-n-drop/virtual_fs.c
- Revision:
- 0:01f31e923fe2
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/source/daplink/drag-n-drop/virtual_fs.c Tue Apr 07 12:55:42 2020 +0200
@@ -0,0 +1,744 @@
+/**
+ * @file virtual_fs.c
+ * @brief Implementation of virtual_fs.h
+ *
+ * DAPLink Interface Firmware
+ * Copyright (c) 2009-2016, ARM Limited, All Rights Reserved
+ * SPDX-License-Identifier: Apache-2.0
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may
+ * not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <string.h>
+
+#include "virtual_fs.h"
+#include "info.h"
+#include "settings.h"
+#include "compiler.h"
+#include "util.h"
+
+// Virtual file system driver
+// Limitations:
+// - files must be contiguous
+// - data written cannot be read back
+// - data should only be read once
+
+// FAT16 limitations +- safety margin
+#define FAT_CLUSTERS_MAX (65525 - 100)
+#define FAT_CLUSTERS_MIN (4086 + 100)
+
+typedef struct {
+ uint8_t boot_sector[11];
+ /* DOS 2.0 BPB - Bios Parameter Block, 11 bytes */
+ uint16_t bytes_per_sector;
+ uint8_t sectors_per_cluster;
+ uint16_t reserved_logical_sectors;
+ uint8_t num_fats;
+ uint16_t max_root_dir_entries;
+ uint16_t total_logical_sectors;
+ uint8_t media_descriptor;
+ uint16_t logical_sectors_per_fat;
+ /* DOS 3.31 BPB - Bios Parameter Block, 12 bytes */
+ uint16_t physical_sectors_per_track;
+ uint16_t heads;
+ uint32_t hidden_sectors;
+ uint32_t big_sectors_on_drive;
+ /* Extended BIOS Parameter Block, 26 bytes */
+ uint8_t physical_drive_number;
+ uint8_t not_used;
+ uint8_t boot_record_signature;
+ uint32_t volume_id;
+ char volume_label[11];
+ char file_system_type[8];
+ /* bootstrap data in bytes 62-509 */
+ uint8_t bootstrap[448];
+ /* These entries in place of bootstrap code are the *nix partitions */
+ //uint8_t partition_one[16];
+ //uint8_t partition_two[16];
+ //uint8_t partition_three[16];
+ //uint8_t partition_four[16];
+ /* Mandatory value at bytes 510-511, must be 0xaa55 */
+ uint16_t signature;
+} __attribute__((packed)) mbr_t;
+
+typedef struct file_allocation_table {
+ uint8_t f[512];
+} file_allocation_table_t;
+
+typedef struct FatDirectoryEntry {
+ vfs_filename_t filename;
+ uint8_t attributes;
+ uint8_t reserved;
+ uint8_t creation_time_ms;
+ uint16_t creation_time;
+ uint16_t creation_date;
+ uint16_t accessed_date;
+ uint16_t first_cluster_high_16;
+ uint16_t modification_time;
+ uint16_t modification_date;
+ uint16_t first_cluster_low_16;
+ uint32_t filesize;
+} __attribute__((packed)) FatDirectoryEntry_t;
+COMPILER_ASSERT(sizeof(FatDirectoryEntry_t) == 32);
+
+// to save RAM all files must be in the first root dir entry (512 bytes)
+// but 2 actually exist on disc (32 entries) to accomodate hidden OS files,
+// folders and metadata
+typedef struct root_dir {
+ FatDirectoryEntry_t f[32];
+} root_dir_t;
+
+typedef struct virtual_media {
+ vfs_read_cb_t read_cb;
+ vfs_write_cb_t write_cb;
+ uint32_t length;
+} virtual_media_t;
+
+static uint32_t read_zero(uint32_t offset, uint8_t *data, uint32_t size);
+static void write_none(uint32_t offset, const uint8_t *data, uint32_t size);
+
+static uint32_t read_mbr(uint32_t offset, uint8_t *data, uint32_t size);
+static uint32_t read_fat(uint32_t offset, uint8_t *data, uint32_t size);
+static uint32_t read_dir(uint32_t offset, uint8_t *data, uint32_t size);
+static void write_dir(uint32_t offset, const uint8_t *data, uint32_t size);
+static void file_change_cb_stub(const vfs_filename_t filename, vfs_file_change_t change,
+ vfs_file_t file, vfs_file_t new_file_data);
+static uint32_t cluster_to_sector(uint32_t cluster_idx);
+static bool filename_valid(const vfs_filename_t filename);
+static bool filename_character_valid(char character);
+
+// If sector size changes update comment below
+COMPILER_ASSERT(0x0200 == VFS_SECTOR_SIZE);
+// If root directory size changes update max_root_dir_entries
+COMPILER_ASSERT(0x0020 == sizeof(root_dir_t) / sizeof(FatDirectoryEntry_t));
+static const mbr_t mbr_tmpl = {
+ /*uint8_t[11]*/.boot_sector = {
+ 0xEB, 0x3C, 0x90,
+ 'M', 'S', 'D', '0', 'S', '4', '.', '1' // OEM Name in text (8 chars max)
+ },
+ /*uint16_t*/.bytes_per_sector = 0x0200, // 512 bytes per sector
+ /*uint8_t */.sectors_per_cluster = 0x08, // 4k cluser
+ /*uint16_t*/.reserved_logical_sectors = 0x0001, // mbr is 1 sector
+ /*uint8_t */.num_fats = 0x02, // 2 FATs
+ /*uint16_t*/.max_root_dir_entries = 0x0020, // 32 dir entries (max)
+ /*uint16_t*/.total_logical_sectors = 0x1f50, // sector size * # of sectors = drive size
+ /*uint8_t */.media_descriptor = 0xf8, // fixed disc = F8, removable = F0
+ /*uint16_t*/.logical_sectors_per_fat = 0x0001, // FAT is 1k - ToDO:need to edit this
+ /*uint16_t*/.physical_sectors_per_track = 0x0001, // flat
+ /*uint16_t*/.heads = 0x0001, // flat
+ /*uint32_t*/.hidden_sectors = 0x00000000, // before mbt, 0
+ /*uint32_t*/.big_sectors_on_drive = 0x00000000, // 4k sector. not using large clusters
+ /*uint8_t */.physical_drive_number = 0x00,
+ /*uint8_t */.not_used = 0x00, // Current head. Linux tries to set this to 0x1
+ /*uint8_t */.boot_record_signature = 0x29, // signature is present
+ /*uint32_t*/.volume_id = 0x27021974, // serial number
+ // needs to match the root dir label
+ /*char[11]*/.volume_label = {'D', 'A', 'P', 'L', 'I', 'N', 'K', '-', 'D', 'N', 'D'},
+ // unused by msft - just a label (FAT, FAT12, FAT16)
+ /*char[8] */.file_system_type = {'F', 'A', 'T', '1', '6', ' ', ' ', ' '},
+
+ /* BOOTSTRAP SOURCE CODE AND PAYLOAD GENERATOR
+ * PRINTS OUT WARNING MESSAGE ON ACCIDENTAL BOOT FROM DAPLINK
+ 1 [BITS 16]
+ 2 %define BLSTART 0x3E
+ 3 %define BLLEN 448
+ 4
+ 5 00000000 FA cli
+ 6 00000001 B8C007 mov ax, 07C0h
+ 7 00000004 052001 add ax, 288
+ 8 00000007 8ED0 mov ss, ax
+ 9 00000009 BC0010 mov sp, 4096
+ 10 0000000C B8C007 mov ax, 07C0h
+ 11 0000000F 8ED8 mov ds, ax
+ 12 00000011 BE[6D00] mov si,message+BLSTART
+ 13 00000014 E80B00 call print
+ 14 00000017 EBFE jmp $
+ 15
+ 16 printc:
+ 17 00000019 B40E mov ah, 0x0E
+ 18 0000001B B700 mov bh, 0x00
+ 19 0000001D B307 mov bl, 0x07
+ 20 0000001F CD10 int 0x10
+ 21 00000021 C3 ret
+ 22
+ 23 print:
+ 24 nextc:
+ 25 00000022 8A04 mov al, [si]
+ 26 00000024 46 inc si
+ 27 00000025 08C0 or al, al
+ 28 00000027 7405 jz return
+ 29 00000029 E8EDFF call printc
+ 30 0000002C EBF4 jmp nextc
+ 31 return:
+ 32 0000002E C3 ret
+ 33
+ 34 0000002F 504C45415345205245- message db 'PLEASE REMOVE THE ARM MBED DAPLINK USB DEVICE AND REBOOT THE SYSTEM..', 0
+ 35 00000038 4D4F56452054484520-
+ 36 00000041 41524D204D42454420-
+ 37 0000004A 4441504C494E4B2055-
+ 38 00000053 534220444556494345-
+ 39 0000005C 20414E44205245424F-
+ 40 00000065 4F5420544845205359-
+ 41 0000006E 5354454D2E2E00
+ 42
+ 43 00000075 00<rept> times BLLEN-($-$$) db 0
+
+ USE BELOW SCRIPT TO COMPILE BOOTSTRAP AND GENERATE PAYLOAD:
+ #!/usr/bin/env python
+ import os
+ os.system('nasm -f bin -o print.bin -l print.lst print.asm')
+ print(open('print.lst','r').read())
+ x=1
+ for c in open('print.bin','rb').read():
+ print('0x%02X, '%c, end='' if x % 16 else '\n')
+ x += 1
+ */
+ /*uint8_t[448]*/.bootstrap = {
+ 0xFA, 0xB8, 0xC0, 0x07, 0x05, 0x20, 0x01, 0x8E, 0xD0, 0xBC, 0x00, 0x10, 0xB8, 0xC0, 0x07, 0x8E,
+ 0xD8, 0xBE, 0x6D, 0x00, 0xE8, 0x0B, 0x00, 0xEB, 0xFE, 0xB4, 0x0E, 0xB7, 0x00, 0xB3, 0x07, 0xCD,
+ 0x10, 0xC3, 0x8A, 0x04, 0x46, 0x08, 0xC0, 0x74, 0x05, 0xE8, 0xED, 0xFF, 0xEB, 0xF4, 0xC3, 0x50,
+ 0x4C, 0x45, 0x41, 0x53, 0x45, 0x20, 0x52, 0x45, 0x4D, 0x4F, 0x56, 0x45, 0x20, 0x54, 0x48, 0x45,
+ 0x20, 0x41, 0x52, 0x4D, 0x20, 0x4D, 0x42, 0x45, 0x44, 0x20, 0x44, 0x41, 0x50, 0x4C, 0x49, 0x4E,
+ 0x4B, 0x20, 0x55, 0x53, 0x42, 0x20, 0x44, 0x45, 0x56, 0x49, 0x43, 0x45, 0x20, 0x41, 0x4E, 0x44,
+ 0x20, 0x52, 0x45, 0x42, 0x4F, 0x4F, 0x54, 0x20, 0x54, 0x48, 0x45, 0x20, 0x53, 0x59, 0x53, 0x54,
+ 0x45, 0x4D, 0x2E, 0x2E, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+ },
+ // Signature MUST be 0xAA55 to maintain compatibility (i.e. with Android).
+ /*uint16_t*/.signature = 0xAA55,
+};
+
+enum virtual_media_idx_t {
+ MEDIA_IDX_MBR = 0,
+ MEDIA_IDX_FAT1,
+ MEDIA_IDX_FAT2,
+ MEDIA_IDX_ROOT_DIR,
+
+ MEDIA_IDX_COUNT
+};
+
+// Note - everything in virtual media must be a multiple of VFS_SECTOR_SIZE
+const virtual_media_t virtual_media_tmpl[] = {
+ /* Read CB Write CB Region Size Region Name */
+ { read_mbr, write_none, VFS_SECTOR_SIZE }, /* MBR */
+ { read_fat, write_none, 0 /* Set at runtime */ }, /* FAT1 */
+ { read_fat, write_none, 0 /* Set at runtime */ }, /* FAT2 */
+ { read_dir, write_dir, VFS_SECTOR_SIZE * 2 }, /* Root Dir */
+ /* Raw filesystem contents follow */
+};
+// Keep virtual_media_idx_t in sync with virtual_media_tmpl
+COMPILER_ASSERT(MEDIA_IDX_COUNT == ARRAY_SIZE(virtual_media_tmpl));
+
+static const FatDirectoryEntry_t root_dir_entry = {
+ /*uint8_t[11] */ .filename = {""},
+ /*uint8_t */ .attributes = VFS_FILE_ATTR_VOLUME_LABEL | VFS_FILE_ATTR_ARCHIVE,
+ /*uint8_t */ .reserved = 0x00,
+ /*uint8_t */ .creation_time_ms = 0x00,
+ /*uint16_t*/ .creation_time = 0x0000,
+ /*uint16_t*/ .creation_date = 0x0000,
+ /*uint16_t*/ .accessed_date = 0x0000,
+ /*uint16_t*/ .first_cluster_high_16 = 0x0000,
+ /*uint16_t*/ .modification_time = 0x8E41,
+ /*uint16_t*/ .modification_date = 0x32bb,
+ /*uint16_t*/ .first_cluster_low_16 = 0x0000,
+ /*uint32_t*/ .filesize = 0x00000000
+};
+
+static const FatDirectoryEntry_t dir_entry_tmpl = {
+ /*uint8_t[11] */ .filename = {""},
+ /*uint8_t */ .attributes = VFS_FILE_ATTR_READ_ONLY,
+ /*uint8_t */ .reserved = 0x00,
+ /*uint8_t */ .creation_time_ms = 0x00,
+ /*uint16_t*/ .creation_time = 0x0000,
+ /*uint16_t*/ .creation_date = 0x4876,
+ /*uint16_t*/ .accessed_date = 0x4876,
+ /*uint16_t*/ .first_cluster_high_16 = 0x0000,
+ /*uint16_t*/ .modification_time = 0x83dc,
+ /*uint16_t*/ .modification_date = 0x4876,
+ /*uint16_t*/ .first_cluster_low_16 = 0x0000,
+ /*uint32_t*/ .filesize = 0x00000000
+};
+
+mbr_t mbr;
+file_allocation_table_t fat;
+virtual_media_t virtual_media[16];
+root_dir_t dir_current;
+uint8_t file_count;
+vfs_file_change_cb_t file_change_cb;
+uint32_t virtual_media_idx;
+uint32_t fat_idx;
+uint32_t dir_idx;
+uint32_t data_start;
+
+// Virtual media must be larger than the template
+COMPILER_ASSERT(sizeof(virtual_media) > sizeof(virtual_media_tmpl));
+
+static void write_fat(file_allocation_table_t *fat, uint32_t idx, uint16_t val)
+{
+ uint32_t low_idx;
+ uint32_t high_idx;
+ low_idx = idx * 2 + 0;
+ high_idx = idx * 2 + 1;
+
+ // Assert that this is still within the fat table
+ if (high_idx >= ARRAY_SIZE(fat->f)) {
+ util_assert(0);
+ return;
+ }
+
+ fat->f[low_idx] = (val >> 0) & 0xFF;
+ fat->f[high_idx] = (val >> 8) & 0xFF;
+}
+
+void vfs_init(const vfs_filename_t drive_name, uint32_t disk_size)
+{
+ uint32_t i;
+ uint32_t num_clusters;
+ uint32_t total_sectors;
+ // Clear everything
+ memset(&mbr, 0, sizeof(mbr));
+ memset(&fat, 0, sizeof(fat));
+ fat_idx = 0;
+ memset(&virtual_media, 0, sizeof(virtual_media));
+ memset(&dir_current, 0, sizeof(dir_current));
+ dir_idx = 0;
+ file_count = 0;
+ file_change_cb = file_change_cb_stub;
+ virtual_media_idx = 0;
+ data_start = 0;
+ // Initialize MBR
+ memcpy(&mbr, &mbr_tmpl, sizeof(mbr_t));
+ total_sectors = ((disk_size + KB(64)) / mbr.bytes_per_sector);
+ // Make sure this is the right size for a FAT16 volume
+ if (total_sectors < FAT_CLUSTERS_MIN * mbr.sectors_per_cluster) {
+ util_assert(0);
+ total_sectors = FAT_CLUSTERS_MIN * mbr.sectors_per_cluster;
+ } else if (total_sectors > FAT_CLUSTERS_MAX * mbr.sectors_per_cluster) {
+ util_assert(0);
+ total_sectors = FAT_CLUSTERS_MAX * mbr.sectors_per_cluster;
+ }
+ if (total_sectors >= 0x10000) {
+ mbr.total_logical_sectors = 0;
+ mbr.big_sectors_on_drive = total_sectors;
+ } else {
+ mbr.total_logical_sectors = total_sectors;
+ mbr.big_sectors_on_drive = 0;
+ }
+ // FAT table will likely be larger than needed, but this is allowed by the
+ // fat specification
+ num_clusters = total_sectors / mbr.sectors_per_cluster;
+ mbr.logical_sectors_per_fat = (num_clusters * 2 + VFS_SECTOR_SIZE - 1) / VFS_SECTOR_SIZE;
+ // Initailize virtual media
+ memcpy(&virtual_media, &virtual_media_tmpl, sizeof(virtual_media_tmpl));
+ virtual_media[MEDIA_IDX_FAT1].length = VFS_SECTOR_SIZE * mbr.logical_sectors_per_fat;
+ virtual_media[MEDIA_IDX_FAT2].length = VFS_SECTOR_SIZE * mbr.logical_sectors_per_fat;
+ // Initialize indexes
+ virtual_media_idx = MEDIA_IDX_COUNT;
+ data_start = 0;
+
+ for (i = 0; i < ARRAY_SIZE(virtual_media_tmpl); i++) {
+ data_start += virtual_media[i].length;
+ }
+
+ // Initialize FAT
+ fat_idx = 0;
+ write_fat(&fat, fat_idx, 0xFFF8); // Media type "media_descriptor"
+ fat_idx++;
+ write_fat(&fat, fat_idx, 0xFFFF); // FAT12 - always 0xFFF (no meaning), FAT16 - dirty/clean (clean = 0xFFFF)
+ fat_idx++;
+ // Initialize root dir
+ dir_idx = 0;
+ dir_current.f[dir_idx] = root_dir_entry;
+ memcpy(dir_current.f[dir_idx].filename, drive_name, sizeof(dir_current.f[0].filename));
+ dir_idx++;
+}
+
+uint32_t vfs_get_total_size()
+{
+ uint32_t size;
+ if (mbr.total_logical_sectors > 0) {
+ size = mbr.total_logical_sectors * mbr.bytes_per_sector;
+ } else if (mbr.big_sectors_on_drive > 0) {
+ size = mbr.big_sectors_on_drive * mbr.bytes_per_sector;
+ } else {
+ size = 0;
+ util_assert(0);
+ }
+ return size;
+}
+
+vfs_file_t vfs_create_file(const vfs_filename_t filename, vfs_read_cb_t read_cb, vfs_write_cb_t write_cb, uint32_t len)
+{
+ uint32_t first_cluster;
+ FatDirectoryEntry_t *de;
+ uint32_t clusters;
+ uint32_t cluster_size;
+ uint32_t i;
+ util_assert(filename_valid(filename));
+ // Compute the number of clusters in the file
+ cluster_size = mbr.bytes_per_sector * mbr.sectors_per_cluster;
+ clusters = (len + cluster_size - 1) / cluster_size;
+ // Write the cluster chain to the fat table
+ first_cluster = 0;
+
+ if (len > 0) {
+ first_cluster = fat_idx;
+
+ for (i = 0; i < clusters - 1; i++) {
+ write_fat(&fat, fat_idx, fat_idx + 1);
+ fat_idx++;
+ }
+
+ write_fat(&fat, fat_idx, 0xFFFF);
+ fat_idx++;
+ }
+
+ // Update directory entry
+ if (dir_idx >= ARRAY_SIZE(dir_current.f)) {
+ util_assert(0);
+ return VFS_FILE_INVALID;
+ }
+
+ de = &dir_current.f[dir_idx];
+ dir_idx++;
+ memcpy(de, &dir_entry_tmpl, sizeof(dir_entry_tmpl));
+ memcpy(de->filename, filename, 11);
+ de->filesize = len;
+ de->first_cluster_high_16 = (first_cluster >> 16) & 0xFFFF;
+ de->first_cluster_low_16 = (first_cluster >> 0) & 0xFFFF;
+
+ // Update virtual media
+ if (virtual_media_idx >= ARRAY_SIZE(virtual_media)) {
+ util_assert(0);
+ return VFS_FILE_INVALID;
+ }
+
+ virtual_media[virtual_media_idx].read_cb = read_zero;
+ virtual_media[virtual_media_idx].write_cb = write_none;
+
+ if (0 != read_cb) {
+ virtual_media[virtual_media_idx].read_cb = read_cb;
+ }
+
+ if (0 != write_cb) {
+ virtual_media[virtual_media_idx].write_cb = write_cb;
+ }
+
+ virtual_media[virtual_media_idx].length = clusters * mbr.bytes_per_sector * mbr.sectors_per_cluster;
+ virtual_media_idx++;
+ file_count += 1;
+ return de;
+}
+
+void vfs_file_set_attr(vfs_file_t file, vfs_file_attr_bit_t attr)
+{
+ FatDirectoryEntry_t *de = file;
+ de->attributes = attr;
+}
+
+vfs_sector_t vfs_file_get_start_sector(vfs_file_t file)
+{
+ FatDirectoryEntry_t *de = file;
+
+ if (vfs_file_get_size(file) == 0) {
+ return VFS_INVALID_SECTOR;
+ }
+
+ return cluster_to_sector(de->first_cluster_low_16);
+}
+
+uint32_t vfs_file_get_size(vfs_file_t file)
+{
+ FatDirectoryEntry_t *de = file;
+ return de->filesize;
+}
+
+vfs_file_attr_bit_t vfs_file_get_attr(vfs_file_t file)
+{
+ FatDirectoryEntry_t *de = file;
+ return (vfs_file_attr_bit_t)de->attributes;
+}
+
+void vfs_set_file_change_callback(vfs_file_change_cb_t cb)
+{
+ file_change_cb = cb;
+}
+
+void vfs_read(uint32_t requested_sector, uint8_t *buf, uint32_t num_sectors)
+{
+ uint8_t i = 0;
+ uint32_t current_sector;
+ // Zero out the buffer
+ memset(buf, 0, num_sectors * VFS_SECTOR_SIZE);
+ current_sector = 0;
+
+ for (i = 0; i < ARRAY_SIZE(virtual_media); i++) {
+ uint32_t vm_sectors = virtual_media[i].length / VFS_SECTOR_SIZE;
+ uint32_t vm_start = current_sector;
+ uint32_t vm_end = current_sector + vm_sectors;
+
+ // Data can be used in this sector
+ if ((requested_sector >= vm_start) && (requested_sector < vm_end)) {
+ uint32_t sector_offset;
+ uint32_t sectors_to_write = vm_end - requested_sector;
+ sectors_to_write = MIN(sectors_to_write, num_sectors);
+ sector_offset = requested_sector - current_sector;
+ virtual_media[i].read_cb(sector_offset, buf, sectors_to_write);
+ // Update requested sector
+ requested_sector += sectors_to_write;
+ num_sectors -= sectors_to_write;
+ }
+
+ // If there is no more data to be read then break
+ if (num_sectors == 0) {
+ break;
+ }
+
+ // Move to the next virtual media entry
+ current_sector += vm_sectors;
+ }
+}
+
+void vfs_write(uint32_t requested_sector, const uint8_t *buf, uint32_t num_sectors)
+{
+ uint8_t i = 0;
+ uint32_t current_sector;
+ current_sector = 0;
+
+ for (i = 0; i < virtual_media_idx; i++) {
+ uint32_t vm_sectors = virtual_media[i].length / VFS_SECTOR_SIZE;
+ uint32_t vm_start = current_sector;
+ uint32_t vm_end = current_sector + vm_sectors;
+
+ // Data can be used in this sector
+ if ((requested_sector >= vm_start) && (requested_sector < vm_end)) {
+ uint32_t sector_offset;
+ uint32_t sectors_to_read = vm_end - requested_sector;
+ sectors_to_read = MIN(sectors_to_read, num_sectors);
+ sector_offset = requested_sector - current_sector;
+ virtual_media[i].write_cb(sector_offset, buf, sectors_to_read);
+ // Update requested sector
+ requested_sector += sectors_to_read;
+ num_sectors -= sectors_to_read;
+ }
+
+ // If there is no more data to be read then break
+ if (num_sectors == 0) {
+ break;
+ }
+
+ // Move to the next virtual media entry
+ current_sector += vm_sectors;
+ }
+}
+
+static uint32_t read_zero(uint32_t sector_offset, uint8_t *data, uint32_t num_sectors)
+{
+ uint32_t read_size = VFS_SECTOR_SIZE * num_sectors;
+ memset(data, 0, read_size);
+ return read_size;
+}
+
+static void write_none(uint32_t sector_offset, const uint8_t *data, uint32_t num_sectors)
+{
+ // Do nothing
+}
+
+static uint32_t read_mbr(uint32_t sector_offset, uint8_t *data, uint32_t num_sectors)
+{
+ uint32_t read_size = sizeof(mbr_t);
+ COMPILER_ASSERT(sizeof(mbr_t) <= VFS_SECTOR_SIZE);
+
+ if (sector_offset != 0) {
+ // Don't worry about reading other sectors
+ return 0;
+ }
+
+ memcpy(data, &mbr, read_size);
+ return read_size;
+}
+
+/* No need to handle writes to the mbr */
+
+static uint32_t read_fat(uint32_t sector_offset, uint8_t *data, uint32_t num_sectors)
+{
+ uint32_t read_size = sizeof(file_allocation_table_t);
+ COMPILER_ASSERT(sizeof(file_allocation_table_t) <= VFS_SECTOR_SIZE);
+
+ if (sector_offset != 0) {
+ // Don't worry about reading other sectors
+ return 0;
+ }
+
+ memcpy(data, &fat, read_size);
+ return read_size;
+}
+
+/* No need to handle writes to the fat */
+
+static uint32_t read_dir(uint32_t sector_offset, uint8_t *data, uint32_t num_sectors)
+{
+ if ((sector_offset + num_sectors) * VFS_SECTOR_SIZE > sizeof(dir_current)) {
+ // Trying to read too much of the root directory
+ util_assert(0);
+ return 0;
+ }
+
+ // Zero buffer data is VFS_SECTOR_SIZE max
+ memset(data, 0, VFS_SECTOR_SIZE);
+
+ if (sector_offset == 0) { //Handle the first 512 bytes
+ // Copy data that is actually created in the directory
+ memcpy(data, &dir_current.f[0], dir_idx*sizeof(FatDirectoryEntry_t));
+ }
+
+ return num_sectors * VFS_SECTOR_SIZE;
+}
+
+static void write_dir(uint32_t sector_offset, const uint8_t *data, uint32_t num_sectors)
+{
+ FatDirectoryEntry_t *old_entry;
+ FatDirectoryEntry_t *new_entry;
+ uint32_t start_index;
+ uint32_t num_entries;
+ uint32_t i;
+
+ if ((sector_offset + num_sectors) * VFS_SECTOR_SIZE > sizeof(dir_current)) {
+ // Trying to write too much of the root directory
+ util_assert(0);
+ return;
+ }
+
+ start_index = sector_offset * VFS_SECTOR_SIZE / sizeof(FatDirectoryEntry_t);
+ num_entries = num_sectors * VFS_SECTOR_SIZE / sizeof(FatDirectoryEntry_t);
+ old_entry = &dir_current.f[start_index];
+ new_entry = (FatDirectoryEntry_t *)data;
+ // If this is the first sector start at index 1 to get past drive name
+ i = 0 == sector_offset ? 1 : 0;
+
+ for (; i < num_entries; i++) {
+ bool same_name;
+
+ if (0 == memcmp(&old_entry[i], &new_entry[i], sizeof(FatDirectoryEntry_t))) {
+ continue;
+ }
+
+ // If were at this point then something has changed in the file
+ same_name = (0 == memcmp(old_entry[i].filename, new_entry[i].filename, sizeof(new_entry[i].filename))) ? 1 : 0;
+ // Changed
+ file_change_cb(new_entry[i].filename, VFS_FILE_CHANGED, (vfs_file_t)&old_entry[i], (vfs_file_t)&new_entry[i]);
+
+ // Deleted
+ if (0xe5 == (uint8_t)new_entry[i].filename[0]) {
+ file_change_cb(old_entry[i].filename, VFS_FILE_DELETED, (vfs_file_t)&old_entry[i], (vfs_file_t)&new_entry[i]);
+ continue;
+ }
+
+ // Created
+ if (!same_name && filename_valid(new_entry[i].filename)) {
+ file_change_cb(new_entry[i].filename, VFS_FILE_CREATED, (vfs_file_t)&old_entry[i], (vfs_file_t)&new_entry[i]);
+ continue;
+ }
+ }
+
+ memcpy(&dir_current.f[start_index], data, num_sectors * VFS_SECTOR_SIZE);
+}
+
+static void file_change_cb_stub(const vfs_filename_t filename, vfs_file_change_t change, vfs_file_t file, vfs_file_t new_file_data)
+{
+ // Do nothing
+}
+
+static uint32_t cluster_to_sector(uint32_t cluster_idx)
+{
+ uint32_t sectors_before_data = data_start / mbr.bytes_per_sector;
+ return sectors_before_data + (cluster_idx - 2) * mbr.sectors_per_cluster;
+}
+
+static bool filename_valid(const vfs_filename_t filename)
+{
+ // Information on valid 8.3 filenames can be found in
+ // the microsoft hardware whitepaper:
+ //
+ // Microsoft Extensible Firmware Initiative
+ // FAT32 File System Specification
+ // FAT: General Overview of On-Disk Format
+ const char invalid_starting_chars[] = {
+ 0xE5, // Deleted
+ 0x00, // Deleted (and all following entries are free)
+ 0x20, // Space not allowed as first character
+ };
+ uint32_t i;
+
+ // Check for invalid starting characters
+ for (i = 0; i < sizeof(invalid_starting_chars); i++) {
+ if (invalid_starting_chars[i] == filename[0]) {
+ return false;
+ }
+ }
+
+ // Make sure all the characters are valid
+ for (i = 0; i < sizeof(vfs_filename_t); i++) {
+ if (!filename_character_valid(filename[i])) {
+ return false;
+ }
+ }
+
+ // All checks have passed so filename is valid
+ return true;
+}
+
+static bool filename_character_valid(char character)
+{
+ const char invalid_chars[] = {0x22, 0x2A, 0x2B, 0x2C, 0x2E, 0x2F, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F, 0x5B, 0x5C, 0x5D, 0x7C};
+ uint32_t i;
+
+ // Lower case characters are not allowed
+ if ((character >= 'a') && (character <= 'z')) {
+ return false;
+ }
+
+ // Values less than 0x20 are not allowed except 0x5
+ if ((character < 0x20) && (character != 0x5)) {
+ return false;
+ }
+
+ // Check for special characters that are not allowed
+ for (i = 0; i < sizeof(invalid_chars); i++) {
+ if (invalid_chars[i] == character) {
+ return false;
+ }
+ }
+
+ // All of the checks have passed so this is a valid file name character
+ return true;
+}