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BoredOS/src/kernel/fat32.c
boreddevnl fbd0bf880e License headers
2026-02-28 00:19:00 +01:00

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// Copyright (c) 2023-2026 Chris (boreddevnl)
// This software is released under the GNU General Public License v3.0. See LICENSE file for details.
// This header needs to maintain in any file it is present in, as per the GPL license terms.
#include "fat32.h"
#include "memory_manager.h"
#include "io.h"
#include "disk.h"
#include <stdbool.h>
#include <stddef.h>
#include "wm.h"
#define MAX_FILES 256
#define MAX_CLUSTERS 1024
#define MAX_OPEN_HANDLES 32
// In-memory FAT table
static uint32_t fat_table[MAX_CLUSTERS];
static uint8_t cluster_data[MAX_CLUSTERS][FAT32_CLUSTER_SIZE];
// File/Directory tracking
typedef struct {
char full_path[FAT32_MAX_PATH];
char filename[FAT32_MAX_FILENAME];
uint32_t start_cluster;
uint32_t size;
uint32_t attributes;
bool used;
char parent_path[FAT32_MAX_PATH];
} FileEntry;
static FileEntry files[MAX_FILES];
static uint32_t next_cluster = 3; // Start after reserved clusters 0, 1, 2
static FAT32_FileHandle open_handles[MAX_OPEN_HANDLES];
static char current_dir[FAT32_MAX_PATH] = "/";
static char current_drive = 'A';
static int desktop_file_limit = -1;
// === RealFS Definitions ===
typedef struct {
Disk *disk;
uint32_t fat_begin_lba;
uint32_t cluster_begin_lba;
uint32_t sectors_per_cluster;
uint32_t root_cluster;
uint32_t fat_size; // sectors
uint32_t total_sectors;
uint32_t partition_offset; // LBA offset of partition start
bool mounted;
uint32_t cached_fat_sector;
uint8_t cached_fat_buf[512];
} FAT32_Volume;
static FAT32_Volume volumes[26]; // A-Z
// === Helper Functions (Shared) ===
// Serial debug output
static void fs_serial_char(char c) {
while (!(inb(0x3F8 + 5) & 0x20));
outb(0x3F8, c);
}
static void fs_serial_str(const char *s) { while (*s) fs_serial_char(*s++); }
static void fs_serial_num(uint32_t n) {
if (n >= 10) fs_serial_num(n / 10);
fs_serial_char('0' + (n % 10));
}
static size_t fs_strlen(const char *str) {
size_t len = 0;
while (str[len]) len++;
return len;
}
static void fs_strcpy(char *dest, const char *src) {
while (*src) *dest++ = *src++;
*dest = 0;
}
static int fs_strcmp(const char *s1, const char *s2) {
while (*s1 && (*s1 == *s2)) {
s1++;
s2++;
}
return *(const unsigned char*)s1 - *(const unsigned char*)s2;
}
static void fs_strcat(char *dest, const char *src) {
while (*dest) dest++;
fs_strcpy(dest, src);
}
bool fs_starts_with(const char *str, const char *prefix) {
while (*prefix) {
if (*prefix++ != *str++) return false;
}
return true;
}
// Extract filename from path
static void extract_filename(const char *path, char *filename) {
int len = fs_strlen(path);
int i = len - 1;
while (i > 0 && path[i] == '/') i--;
int start = i;
while (start >= 0 && path[start] != '/') start--;
start++;
int j = 0;
for (int k = start; k <= i; k++) {
filename[j++] = path[k];
}
filename[j] = 0;
}
// Extract parent path
static void extract_parent_path(const char *path, char *parent) {
int len = fs_strlen(path);
int i = len - 1;
while (i > 0 && path[i] == '/') i--;
while (i > 0 && path[i] != '/') i--;
if (i == 0) {
parent[0] = '/';
parent[1] = 0;
} else {
for (int j = 0; j < i; j++) {
parent[j] = path[j];
}
parent[i] = 0;
}
}
// Helper to parse drive from path
static char parse_drive_from_path(const char **path_ptr) {
const char *path = *path_ptr;
if (path[0] && path[1] == ':') {
char drive = path[0];
if (drive >= 'a' && drive <= 'z') drive -= 32; // toupper
*path_ptr = path + 2;
return drive;
}
return current_drive;
}
// Normalize path (remove .., ., etc)
void fat32_normalize_path(const char *path, char *normalized) {
char temp[FAT32_MAX_PATH];
int temp_len = 0;
const char *p = path;
char drive = parse_drive_from_path(&p);
if (p[0] == '/') {
fs_strcpy(temp, "/");
temp_len = 1;
} else {
fs_strcpy(temp, current_dir);
temp_len = fs_strlen(temp);
}
int i = 0;
while (p[i]) {
while (p[i] == '/') i++;
if (!p[i]) break;
char component[FAT32_MAX_FILENAME];
int j = 0;
while (p[i] && p[i] != '/' && j < (FAT32_MAX_FILENAME - 1)) {
component[j++] = p[i++];
}
component[j] = 0;
if (fs_strcmp(component, ".") == 0) {
continue;
} else if (fs_strcmp(component, "..") == 0) {
if (temp_len > 1) {
while (temp_len > 0 && temp[temp_len - 1] != '/') temp_len--;
if (temp_len > 1) temp_len--;
temp[temp_len] = 0;
}
} else {
int comp_len = fs_strlen(component);
if (temp_len + comp_len + 2 < FAT32_MAX_PATH) {
if (temp[temp_len - 1] != '/') {
temp[temp_len++] = '/';
temp[temp_len] = 0;
}
fs_strcat(temp, component);
temp_len = fs_strlen(temp);
}
}
}
if (temp_len > 1 && temp[temp_len - 1] == '/') temp[--temp_len] = 0;
fs_strcpy(normalized, temp);
}
// === RAMFS Internal Functions ===
static FileEntry* ramfs_find_file(const char *path) {
char normalized[FAT32_MAX_PATH];
fat32_normalize_path(path, normalized);
for (int i = 0; i < MAX_FILES; i++) {
if (files[i].used && fs_strcmp(files[i].full_path, normalized) == 0) {
return &files[i];
}
}
return NULL;
}
static FileEntry* ramfs_find_free_entry(void) {
for (int i = 0; i < MAX_FILES; i++) {
if (!files[i].used) return &files[i];
}
return NULL;
}
static FAT32_FileHandle* ramfs_find_free_handle(void) {
for (int i = 0; i < MAX_OPEN_HANDLES; i++) {
if (!open_handles[i].valid) return &open_handles[i];
}
return NULL;
}
static uint32_t ramfs_allocate_cluster(void) {
if (next_cluster >= MAX_CLUSTERS) return 0;
uint32_t cluster = next_cluster++;
fat_table[cluster] = 0xFFFFFFFF;
return cluster;
}
static bool check_desktop_limit(const char *normalized_path) {
if (desktop_file_limit < 0) return true;
if (fs_strlen(normalized_path) > 9 &&
normalized_path[0] == '/' &&
normalized_path[1] == 'D' && normalized_path[2] == 'e' &&
normalized_path[3] == 's' && normalized_path[4] == 'k' &&
normalized_path[5] == 't' && normalized_path[6] == 'o' &&
normalized_path[7] == 'p' && normalized_path[8] == '/') {
const char *p = normalized_path + 9;
while (*p) {
if (*p == '/') return true;
p++;
}
FAT32_FileInfo *info = (FAT32_FileInfo*)kmalloc(256 * sizeof(FAT32_FileInfo));
if (!info) return true;
int count = fat32_list_directory("/Desktop", info, 256);
kfree(info);
if (count >= desktop_file_limit) return false;
}
return true;
}
static FAT32_FileHandle* ramfs_open(const char *normalized_path, const char *mode) {
FileEntry *entry = ramfs_find_file(normalized_path);
if (mode[0] == 'r') {
if (!entry || (entry->attributes & ATTR_DIRECTORY)) return NULL;
} else if (mode[0] == 'w' || (mode[0] == 'a')) {
if (!entry) {
if (!check_desktop_limit(normalized_path)) return NULL;
entry = ramfs_find_free_entry();
if (!entry) return NULL;
entry->used = true;
fs_strcpy(entry->full_path, normalized_path);
extract_filename(normalized_path, entry->filename);
extract_parent_path(normalized_path, entry->parent_path);
entry->start_cluster = ramfs_allocate_cluster();
if (!entry->start_cluster) return NULL;
entry->size = 0;
entry->attributes = 0;
}
if (mode[0] == 'w') entry->size = 0;
}
FAT32_FileHandle *handle = ramfs_find_free_handle();
if (!handle) return NULL;
handle->valid = true;
handle->drive = 'A';
handle->cluster = entry->start_cluster;
handle->start_cluster = entry->start_cluster;
handle->position = 0;
handle->size = entry->size;
if (mode[0] == 'r') handle->mode = 0;
else if (mode[0] == 'w') handle->mode = 1;
else {
handle->mode = 2;
handle->position = entry->size;
uint32_t current_cluster = handle->start_cluster;
uint32_t pos = 0;
while (pos + FAT32_CLUSTER_SIZE <= handle->position) {
uint32_t next = fat_table[current_cluster];
if (next >= 0xFFFFFFF8) break;
current_cluster = next;
pos += FAT32_CLUSTER_SIZE;
}
handle->cluster = current_cluster;
}
return handle;
}
static int ramfs_read(FAT32_FileHandle *handle, void *buffer, int size) {
int bytes_read = 0;
uint8_t *buf = (uint8_t *)buffer;
while (bytes_read < size && handle->position < handle->size) {
uint32_t offset_in_cluster = handle->position % FAT32_CLUSTER_SIZE;
int to_read = size - bytes_read;
int available = handle->size - handle->position;
if (to_read > available) to_read = available;
if (to_read > FAT32_CLUSTER_SIZE - offset_in_cluster) to_read = FAT32_CLUSTER_SIZE - offset_in_cluster;
if (handle->cluster >= MAX_CLUSTERS) break;
uint8_t *src = cluster_data[handle->cluster] + offset_in_cluster;
for (int i = 0; i < to_read; i++) buf[bytes_read + i] = src[i];
bytes_read += to_read;
handle->position += to_read;
if (handle->position % FAT32_CLUSTER_SIZE == 0 && handle->position < handle->size) {
handle->cluster = fat_table[handle->cluster];
}
}
return bytes_read;
}
static int ramfs_write(FAT32_FileHandle *handle, const void *buffer, int size) {
int bytes_written = 0;
const uint8_t *buf = (const uint8_t *)buffer;
if (handle->position > 0 && (handle->position % FAT32_CLUSTER_SIZE) == 0) {
uint32_t next = fat_table[handle->cluster];
if (next >= 0xFFFFFFF8) {
next = ramfs_allocate_cluster();
if (!next) return 0;
fat_table[handle->cluster] = next;
}
handle->cluster = next;
}
while (bytes_written < size) {
uint32_t offset_in_cluster = handle->position % FAT32_CLUSTER_SIZE;
int to_write = size - bytes_written;
if (to_write > FAT32_CLUSTER_SIZE - offset_in_cluster) to_write = FAT32_CLUSTER_SIZE - offset_in_cluster;
if (handle->cluster >= MAX_CLUSTERS) break;
uint8_t *dest = cluster_data[handle->cluster] + offset_in_cluster;
for (int i = 0; i < to_write; i++) dest[i] = buf[bytes_written + i];
bytes_written += to_write;
handle->position += to_write;
if (handle->position > handle->size) handle->size = handle->position;
if (offset_in_cluster + to_write >= FAT32_CLUSTER_SIZE && bytes_written < size) {
uint32_t next = ramfs_allocate_cluster();
if (!next) break;
fat_table[handle->cluster] = next;
handle->cluster = next;
}
}
for (int i = 0; i < MAX_FILES; i++) {
if (files[i].used && files[i].start_cluster == handle->start_cluster) {
files[i].size = handle->size;
break;
}
}
wm_notify_fs_change();
return bytes_written;
}
// === RealFS Implementation ===
static bool realfs_mount(char drive) {
int idx = drive - 'A';
if (idx < 0 || idx >= 26) return false;
if (volumes[idx].mounted) return true;
Disk *disk = disk_get_by_letter(drive);
if (!disk) return false;
// Use partition LBA offset from disk (set during MBR parsing)
uint32_t part_offset = disk->partition_lba_offset;
uint8_t *sect0 = (uint8_t*)kmalloc(512);
if (!sect0) return false;
// Read BPB from partition start (sector 0 for raw, partition LBA for MBR)
if (disk->read_sector(disk, part_offset, sect0) != 0) {
kfree(sect0);
return false;
}
FAT32_BootSector *bpb = (FAT32_BootSector*)sect0;
if (bpb->boot_signature_value != 0xAA55) {
kfree(sect0);
return false;
}
volumes[idx].disk = disk;
volumes[idx].partition_offset = part_offset;
volumes[idx].fat_begin_lba = part_offset + bpb->reserved_sectors;
volumes[idx].cluster_begin_lba = part_offset + bpb->reserved_sectors + (bpb->num_fats * bpb->sectors_per_fat_32);
volumes[idx].sectors_per_cluster = bpb->sectors_per_cluster;
volumes[idx].root_cluster = bpb->root_cluster;
volumes[idx].fat_size = bpb->sectors_per_fat_32;
volumes[idx].total_sectors = bpb->total_sectors_32;
volumes[idx].mounted = true;
volumes[idx].cached_fat_sector = 0xFFFFFFFF;
fs_serial_str("[FAT32] mounted drive ");
fs_serial_char(drive);
fs_serial_str(": part_offset=");
fs_serial_num(part_offset);
fs_serial_str(" fat_lba=");
fs_serial_num(volumes[idx].fat_begin_lba);
fs_serial_str(" cluster_lba=");
fs_serial_num(volumes[idx].cluster_begin_lba);
fs_serial_str(" spc=");
fs_serial_num(volumes[idx].sectors_per_cluster);
fs_serial_str(" root_cl=");
fs_serial_num(volumes[idx].root_cluster);
fs_serial_str("\n");
kfree(sect0);
return true;
}
static uint32_t realfs_next_cluster(FAT32_Volume *vol, uint32_t cluster);
static void realfs_update_dir_entry_size(FAT32_Volume *vol, FAT32_FileHandle *handle) {
if (handle->dir_sector != 0 && handle->dir_offset != 0xFFFFFFFF && handle->dir_offset < 512) {
uint8_t *dir_buf = (uint8_t*)kmalloc(512);
if (dir_buf && vol->disk->read_sector(vol->disk, handle->dir_sector, dir_buf) == 0) {
FAT32_DirEntry *entry = (FAT32_DirEntry*)(dir_buf + handle->dir_offset);
// Update start cluster if it exists
if (handle->start_cluster != 0) {
entry->start_cluster_high = (handle->start_cluster >> 16);
entry->start_cluster_low = (handle->start_cluster & 0xFFFF);
}
// Always update file size
entry->file_size = handle->size;
// Write back
vol->disk->write_sector(vol->disk, handle->dir_sector, dir_buf);
}
if (dir_buf) kfree(dir_buf);
}
}
static uint32_t realfs_next_cluster(FAT32_Volume *vol, uint32_t cluster) {
uint32_t fat_sector = vol->fat_begin_lba + (cluster * 4) / 512;
uint32_t fat_offset = (cluster * 4) % 512;
if (vol->cached_fat_sector != fat_sector) {
if (vol->disk->read_sector(vol->disk, fat_sector, vol->cached_fat_buf) != 0) {
return 0xFFFFFFFF;
}
vol->cached_fat_sector = fat_sector;
}
uint32_t next = *(uint32_t*)&vol->cached_fat_buf[fat_offset];
next &= 0x0FFFFFFF; // Mask top 4 bits
return next;
}
static int realfs_read_cluster(FAT32_Volume *vol, uint32_t cluster, uint8_t *buffer) {
uint32_t lba = vol->cluster_begin_lba + (cluster - 2) * vol->sectors_per_cluster;
for (uint32_t i = 0; i < vol->sectors_per_cluster; i++) {
if (vol->disk->read_sector(vol->disk, lba + i, buffer + (i * 512)) != 0) return -1;
}
return 0;
}
static void to_dos_filename(const char *filename, char *out) {
for (int i = 0; i < 11; i++) out[i] = ' ';
int len = fs_strlen(filename);
int dot = -1;
for (int i = len - 1; i >= 0; i--) {
if (filename[i] == '.') { dot = i; break; }
}
int name_len = (dot == -1) ? len : dot;
if (name_len > 8) name_len = 8;
for (int i = 0; i < name_len; i++) {
char c = filename[i];
// Preserve case - don't convert to uppercase
out[i] = c;
}
if (dot != -1) {
int ext_len = len - dot - 1;
if (ext_len > 3) ext_len = 3;
for (int i = 0; i < ext_len; i++) {
char c = filename[dot + 1 + i];
// Preserve case - don't convert to uppercase
out[8 + i] = c;
}
}
}
static FAT32_FileHandle* realfs_open(char drive, const char *path, const char *mode) {
int vol_idx = drive - 'A';
if (!volumes[vol_idx].mounted) {
if (!realfs_mount(drive)) return NULL;
}
FAT32_Volume *vol = &volumes[vol_idx];
// Parse path to find start cluster
uint32_t current_cluster = vol->root_cluster;
// Skip leading slash
const char *p = path;
if (*p == '/') p++;
fs_serial_str("[FAT32] realfs_open drive=");
fs_serial_char(drive);
fs_serial_str(" path='");
fs_serial_str(path);
fs_serial_str("' mode=");
fs_serial_char(mode[0]);
fs_serial_str("\n");
if (*p == 0) {
// Root dir
if (mode[0] == 'w') return NULL; // Cannot write to root as file
FAT32_FileHandle *fh = ramfs_find_free_handle(); // Reuse handle pool
if (fh) {
fh->valid = true;
fh->drive = drive;
fh->start_cluster = vol->root_cluster;
fh->cluster = vol->root_cluster;
fh->position = 0;
fh->size = 0; // Unknown for root
fh->mode = 0;
return fh;
}
return NULL;
}
char component[256];
bool found = false;
uint32_t file_size = 0;
uint32_t entry_sector = 0;
uint32_t entry_offset = 0;
while (*p) {
// Extract component
int i = 0;
while (*p && *p != '/') {
component[i++] = *p++;
}
component[i] = 0;
if (*p == '/') p++; // Skip separator
// Search in current_cluster
found = false;
uint32_t search_cluster = current_cluster;
uint8_t *cluster_buf = (uint8_t*)kmalloc(vol->sectors_per_cluster * 512);
while (search_cluster < 0x0FFFFFF8) {
if (realfs_read_cluster(vol, search_cluster, cluster_buf) != 0) break;
FAT32_DirEntry *entry = (FAT32_DirEntry*)cluster_buf;
int entries_per_cluster = (vol->sectors_per_cluster * 512) / 32;
for (int e = 0; e < entries_per_cluster; e++) {
if (entry[e].filename[0] == 0) break; // End of dir
if (entry[e].filename[0] == 0xE5) continue; // Deleted
if (entry[e].attributes == 0x0F) continue; // LFN entry
if (entry[e].attributes & ATTR_VOLUME_ID) continue; // Volume label
// Compare name (simplistic 8.3 matching)
char name[13];
int n = 0;
for (int k = 0; k < 8 && entry[e].filename[k] != ' '; k++) name[n++] = entry[e].filename[k];
if (entry[e].extension[0] != ' ') {
name[n++] = '.';
for (int k = 0; k < 3 && entry[e].extension[k] != ' '; k++) name[n++] = entry[e].extension[k];
}
name[n] = 0;
// Case insensitive compare
bool match = true;
for (int c = 0; c < n+1; c++) {
char c1 = name[c];
char c2 = component[c];
if (c1 >= 'a' && c1 <= 'z') c1 -= 32;
if (c2 >= 'a' && c2 <= 'z') c2 -= 32;
if (c1 != c2) { match = false; break; }
}
if (match) {
uint32_t cluster = (entry[e].start_cluster_high << 16) | entry[e].start_cluster_low;
fs_serial_str("[FAT32] MATCH '");
fs_serial_str(name);
fs_serial_str("' cluster=");
fs_serial_num(cluster);
fs_serial_str(" size=");
fs_serial_num(entry[e].file_size);
fs_serial_str("\n");
uint32_t lba = vol->cluster_begin_lba + (search_cluster - 2) * vol->sectors_per_cluster;
int sect_in_cluster = (e * 32) / 512;
entry_sector = lba + sect_in_cluster;
entry_offset = (e * 32) % 512;
if (*p == 0) {
// Found target
current_cluster = cluster;
file_size = entry[e].file_size;
found = true;
} else {
// It must be a directory
if (entry[e].attributes & ATTR_DIRECTORY) {
current_cluster = cluster;
found = true;
}
}
break;
}
}
if (found) break;
search_cluster = realfs_next_cluster(vol, search_cluster);
}
if (!found) {
if ((mode[0] == 'w' || mode[0] == 'a') && *p == 0) {
// Create file logic
char dos_name[11];
to_dos_filename(component, dos_name);
// Find free entry in current_cluster (which is the directory)
search_cluster = current_cluster;
bool found_free = false;
uint32_t free_sector = 0;
uint32_t free_offset = 0;
while (search_cluster < 0x0FFFFFF8 && !found_free) {
if (realfs_read_cluster(vol, search_cluster, cluster_buf) != 0) break;
FAT32_DirEntry *entries = (FAT32_DirEntry*)cluster_buf;
int count = (vol->sectors_per_cluster * 512) / 32;
for (int e = 0; e < count; e++) {
if (entries[e].filename[0] == 0 || entries[e].filename[0] == 0xE5) {
uint32_t lba = vol->cluster_begin_lba + (search_cluster - 2) * vol->sectors_per_cluster;
int sect_in_cluster = (e * 32) / 512;
free_sector = lba + sect_in_cluster;
free_offset = (e * 32) % 512;
found_free = true;
break;
}
}
if (!found_free) search_cluster = realfs_next_cluster(vol, search_cluster);
}
if (found_free) {
uint8_t *sect_buf = (uint8_t*)kmalloc(512);
vol->disk->read_sector(vol->disk, free_sector, sect_buf);
FAT32_DirEntry *d = (FAT32_DirEntry*)(sect_buf + free_offset);
for(int k=0; k<8; k++) d->filename[k] = dos_name[k];
for(int k=0; k<3; k++) d->extension[k] = dos_name[8+k];
d->attributes = ATTR_ARCHIVE;
d->start_cluster_high = 0;
d->start_cluster_low = 0;
d->file_size = 0;
// Write to disk
if (vol->disk->write_sector(vol->disk, free_sector, sect_buf) != 0) {
// Write failed, free the buffer and return NULL
kfree(sect_buf);
kfree(cluster_buf);
return NULL;
}
kfree(sect_buf);
FAT32_FileHandle *fh = ramfs_find_free_handle();
if (fh) {
fh->valid = true;
fh->drive = drive;
fh->start_cluster = 0;
fh->cluster = 0;
fh->position = 0;
fh->size = 0;
fh->mode = 1; // Write
fh->dir_sector = free_sector;
fh->dir_offset = free_offset;
kfree(cluster_buf);
return fh;
}
}
kfree(cluster_buf);
return NULL;
}
kfree(cluster_buf);
return NULL;
}
kfree(cluster_buf);
}
// Found file/dir
FAT32_FileHandle *fh = ramfs_find_free_handle();
if (fh) {
fh->valid = true;
fh->drive = drive;
fh->start_cluster = current_cluster;
fh->cluster = current_cluster;
fh->position = 0;
fh->size = file_size;
fh->mode = (mode[0] == 'w' ? 1 : 0); // Only R/W supported
fh->dir_sector = entry_sector;
fh->dir_offset = entry_offset;
return fh;
}
return NULL;
}
static int realfs_read(FAT32_FileHandle *handle, void *buffer, int size) {
int vol_idx = handle->drive - 'A';
FAT32_Volume *vol = &volumes[vol_idx];
uint8_t *cluster_buf = (uint8_t*)kmalloc(vol->sectors_per_cluster * 512);
if (!cluster_buf) return 0;
int bytes_read = 0;
uint8_t *out_buf = (uint8_t*)buffer;
uint32_t cluster_size = vol->sectors_per_cluster * 512;
while (bytes_read < size && handle->position < handle->size) {
if (realfs_read_cluster(vol, handle->cluster, cluster_buf) != 0) break;
uint32_t offset = handle->position % cluster_size;
int to_copy = size - bytes_read;
int available = cluster_size - offset;
if (handle->size - handle->position < available) available = handle->size - handle->position;
if (to_copy > available) to_copy = available;
for (int i = 0; i < to_copy; i++) {
out_buf[bytes_read + i] = cluster_buf[offset + i];
}
bytes_read += to_copy;
handle->position += to_copy;
if (handle->position % cluster_size == 0 && handle->position < handle->size) {
handle->cluster = realfs_next_cluster(vol, handle->cluster);
if (handle->cluster >= 0x0FFFFFF8) break;
}
}
kfree(cluster_buf);
return bytes_read;
}
static int realfs_write_cluster(FAT32_Volume *vol, uint32_t cluster, const uint8_t *buffer) {
uint32_t lba = vol->cluster_begin_lba + (cluster - 2) * vol->sectors_per_cluster;
for (uint32_t i = 0; i < vol->sectors_per_cluster; i++) {
if (vol->disk->write_sector(vol->disk, lba + i, buffer + (i * 512)) != 0) return -1;
}
return 0;
}
static uint32_t realfs_allocate_cluster(FAT32_Volume *vol) {
uint32_t current = 2;
uint32_t fat_entries = (vol->fat_size * 512) / 4;
uint8_t *fat_buf = (uint8_t*)kmalloc(512);
if (!fat_buf) return 0;
uint32_t cached_sector = 0xFFFFFFFF;
while (current < fat_entries) {
uint32_t sector = vol->fat_begin_lba + (current * 4) / 512;
uint32_t offset = (current * 4) % 512;
if (sector != cached_sector) {
vol->disk->read_sector(vol->disk, sector, fat_buf);
cached_sector = sector;
}
uint32_t val = *(uint32_t*)&fat_buf[offset];
if ((val & 0x0FFFFFFF) == 0) {
*(uint32_t*)&fat_buf[offset] = 0x0FFFFFFF; // EOC
vol->disk->write_sector(vol->disk, sector, fat_buf);
if (vol->cached_fat_sector == sector) {
vol->cached_fat_sector = 0xFFFFFFFF;
}
kfree(fat_buf);
return current;
}
current++;
}
kfree(fat_buf);
return 0; // Full
}
static int realfs_write(FAT32_FileHandle *handle, const void *buffer, int size) {
int vol_idx = handle->drive - 'A';
FAT32_Volume *vol = &volumes[vol_idx];
if (handle->start_cluster == 0) {
uint32_t new_cluster = realfs_allocate_cluster(vol);
if (new_cluster == 0) return 0;
handle->start_cluster = new_cluster;
handle->cluster = new_cluster;
// Mark new cluster as EOF in FAT
uint32_t fat_sector = vol->fat_begin_lba + (new_cluster * 4) / 512;
uint32_t fat_offset = (new_cluster * 4) % 512;
uint8_t *fat_buf = (uint8_t*)kmalloc(512);
if (vol->disk->read_sector(vol->disk, fat_sector, fat_buf) == 0) {
*(uint32_t*)&fat_buf[fat_offset] = 0x0FFFFFF8; // EOF marker
vol->disk->write_sector(vol->disk, fat_sector, fat_buf);
}
kfree(fat_buf);
// Initialize the new cluster with zeros to avoid garbage
uint32_t cluster_size_bytes = vol->sectors_per_cluster * 512;
uint8_t *cbuf = (uint8_t*)kmalloc(cluster_size_bytes);
for(uint32_t i=0; i<cluster_size_bytes; i++) cbuf[i] = 0;
realfs_write_cluster(vol, new_cluster, cbuf);
kfree(cbuf);
// Update directory entry immediately with the allocated cluster and initial size
if (handle->dir_sector != 0 && handle->dir_offset != 0xFFFFFFFF && handle->dir_offset < 512) {
uint8_t *dir_buf = (uint8_t*)kmalloc(512);
if (dir_buf && vol->disk->read_sector(vol->disk, handle->dir_sector, dir_buf) == 0) {
FAT32_DirEntry *entry = (FAT32_DirEntry*)(dir_buf + handle->dir_offset);
entry->start_cluster_high = (new_cluster >> 16);
entry->start_cluster_low = (new_cluster & 0xFFFF);
entry->file_size = 0; // Start with size 0
vol->disk->write_sector(vol->disk, handle->dir_sector, dir_buf);
}
if (dir_buf) kfree(dir_buf);
}
}
uint8_t *cluster_buf = (uint8_t*)kmalloc(vol->sectors_per_cluster * 512);
if (!cluster_buf) return 0;
int bytes_written = 0;
const uint8_t *src_buf = (const uint8_t*)buffer;
uint32_t cluster_size = vol->sectors_per_cluster * 512;
while (bytes_written < size) {
if (realfs_read_cluster(vol, handle->cluster, cluster_buf) != 0) break;
uint32_t offset = handle->position % cluster_size;
int to_copy = size - bytes_written;
int available = cluster_size - offset;
if (to_copy > available) to_copy = available;
for (int i = 0; i < to_copy; i++) {
cluster_buf[offset + i] = src_buf[bytes_written + i];
}
if (realfs_write_cluster(vol, handle->cluster, cluster_buf) != 0) break;
bytes_written += to_copy;
handle->position += to_copy;
if (handle->position > handle->size) {
handle->size = handle->position;
}
// Update directory entry after every write to ensure persistence
if (handle->size > 0) {
realfs_update_dir_entry_size(vol, handle);
}
if (handle->position % cluster_size == 0 && bytes_written < size) {
uint32_t next = realfs_next_cluster(vol, handle->cluster);
if (next >= 0x0FFFFFF8) {
uint32_t new_cluster = realfs_allocate_cluster(vol);
if (new_cluster == 0) break;
// Link current cluster to new cluster in FAT
uint32_t fat_sector = vol->fat_begin_lba + (handle->cluster * 4) / 512;
uint32_t fat_offset = (handle->cluster * 4) % 512;
uint8_t *fat_buf = (uint8_t*)kmalloc(512);
if (vol->disk->read_sector(vol->disk, fat_sector, fat_buf) == 0) {
*(uint32_t*)&fat_buf[fat_offset] = new_cluster;
vol->disk->write_sector(vol->disk, fat_sector, fat_buf);
}
kfree(fat_buf);
// Mark new cluster as EOF in FAT
fat_sector = vol->fat_begin_lba + (new_cluster * 4) / 512;
fat_offset = (new_cluster * 4) % 512;
fat_buf = (uint8_t*)kmalloc(512);
if (vol->disk->read_sector(vol->disk, fat_sector, fat_buf) == 0) {
*(uint32_t*)&fat_buf[fat_offset] = 0x0FFFFFF8; // EOF marker
vol->disk->write_sector(vol->disk, fat_sector, fat_buf);
}
kfree(fat_buf);
// Init new cluster
uint8_t *cbuf = (uint8_t*)kmalloc(cluster_size);
for(uint32_t i=0; i<cluster_size; i++) cbuf[i] = 0;
realfs_write_cluster(vol, new_cluster, cbuf);
kfree(cbuf);
next = new_cluster;
}
handle->cluster = next;
}
}
// Final update to directory entry with complete file size before returning
realfs_update_dir_entry_size(vol, handle);
kfree(cluster_buf);
return bytes_written;
}
static bool realfs_delete(char drive, const char *path) {
int vol_idx = drive - 'A';
if (!volumes[vol_idx].mounted) {
if (!realfs_mount(drive)) return false;
}
FAT32_Volume *vol = &volumes[vol_idx];
// Parse path to find start cluster and directory entry location
uint32_t current_cluster = vol->root_cluster;
const char *p = path;
if (*p == '/') p++;
if (*p == 0) {
return false; // Cannot delete root
}
char component[256];
uint32_t file_start_cluster = 0;
uint32_t entry_sector = 0;
uint32_t entry_offset = 0;
bool is_directory = false;
uint8_t *cluster_buf = (uint8_t*)kmalloc(vol->sectors_per_cluster * 512);
if (!cluster_buf) return false;
while (*p) {
// Extract component
int i = 0;
while (*p && *p != '/') {
component[i++] = *p++;
}
component[i] = 0;
if (*p == '/') p++; // Skip separator
// Search in current_cluster
bool found = false;
uint32_t search_cluster = current_cluster;
while (search_cluster < 0x0FFFFFF8) {
if (realfs_read_cluster(vol, search_cluster, cluster_buf) != 0) break;
FAT32_DirEntry *entry = (FAT32_DirEntry*)cluster_buf;
int entries_per_cluster = (vol->sectors_per_cluster * 512) / 32;
for (int e = 0; e < entries_per_cluster; e++) {
if (entry[e].filename[0] == 0) break;
if (entry[e].filename[0] == 0xE5) continue;
if (entry[e].attributes == 0x0F) continue; // Skip LFN entries
if (entry[e].attributes & ATTR_VOLUME_ID) continue; // Skip volume label
// Format name and compare
char name[13];
int n = 0;
for (int k = 0; k < 8 && entry[e].filename[k] != ' '; k++) name[n++] = entry[e].filename[k];
if (entry[e].extension[0] != ' ') {
name[n++] = '.';
for (int k = 0; k < 3 && entry[e].extension[k] != ' '; k++) name[n++] = entry[e].extension[k];
}
name[n] = 0;
// Case insensitive compare
bool match = true;
for (int c = 0; c < n+1; c++) {
char c1 = name[c];
char c2 = component[c];
if (c1 >= 'a' && c1 <= 'z') c1 -= 32;
if (c2 >= 'a' && c2 <= 'z') c2 -= 32;
if (c1 != c2) { match = false; break; }
}
if (match) {
file_start_cluster = (entry[e].start_cluster_high << 16) | entry[e].start_cluster_low;
is_directory = (entry[e].attributes & ATTR_DIRECTORY) != 0;
uint32_t lba = vol->cluster_begin_lba + (search_cluster - 2) * vol->sectors_per_cluster;
int sect_in_cluster = (e * 32) / 512;
entry_sector = lba + sect_in_cluster;
entry_offset = (e * 32) % 512;
if (*p == 0) {
// Found target file/directory to delete
found = true;
} else {
// It must be a directory to continue traversing
if (is_directory) {
current_cluster = file_start_cluster;
found = true;
}
}
break;
}
}
if (found) break;
search_cluster = realfs_next_cluster(vol, search_cluster);
}
if (!found) {
kfree(cluster_buf);
return false; // Path not found
}
if (*p == 0) break; // End of path
}
// 1. Mark directory entry as deleted
uint8_t *entry_buf = (uint8_t*)kmalloc(512);
if (!entry_buf) {
kfree(cluster_buf);
return false;
}
if (vol->disk->read_sector(vol->disk, entry_sector, entry_buf) != 0) {
kfree(entry_buf);
kfree(cluster_buf);
return false;
}
// Mark as deleted
entry_buf[entry_offset] = 0xE5;
if (vol->disk->write_sector(vol->disk, entry_sector, entry_buf) != 0) {
kfree(entry_buf);
kfree(cluster_buf);
return false;
}
// 2. Free all clusters used by the file
if (file_start_cluster != 0 && file_start_cluster < 0x0FFFFFF8) {
uint32_t current = file_start_cluster;
while (current < 0x0FFFFFF8) {
uint32_t next = realfs_next_cluster(vol, current);
// Mark this cluster as free in FAT
uint32_t fat_sector = vol->fat_begin_lba + (current * 4) / 512;
uint32_t fat_offset = (current * 4) % 512;
uint8_t *fat_buf = (uint8_t*)kmalloc(512);
if (!fat_buf) break;
if (vol->disk->read_sector(vol->disk, fat_sector, fat_buf) == 0) {
*(uint32_t*)&fat_buf[fat_offset] = 0; // Free
vol->disk->write_sector(vol->disk, fat_sector, fat_buf);
}
kfree(fat_buf);
current = next;
}
}
kfree(entry_buf);
kfree(cluster_buf);
return true;
}
static int realfs_list_directory(char drive, const char *path, FAT32_FileInfo *entries, int max_entries) {
int vol_idx = drive - 'A';
if (!volumes[vol_idx].mounted) {
if (!realfs_mount(drive)) return 0;
}
FAT32_Volume *vol = &volumes[vol_idx];
FAT32_FileHandle *dir_handle = realfs_open(drive, path, "r");
if (!dir_handle) return 0;
uint32_t current_cluster = dir_handle->start_cluster;
fat32_close(dir_handle); // Return to pool - this invalidates the handle
int count = 0;
uint8_t *cluster_buf = (uint8_t*)kmalloc(vol->sectors_per_cluster * 512);
if (!cluster_buf) return 0;
while (current_cluster < 0x0FFFFFF8 && count < max_entries) {
if (realfs_read_cluster(vol, current_cluster, cluster_buf) != 0) break;
FAT32_DirEntry *entry = (FAT32_DirEntry*)cluster_buf;
int entries_per_cluster = (vol->sectors_per_cluster * 512) / 32;
for (int e = 0; e < entries_per_cluster && count < max_entries; e++) {
if (entry[e].filename[0] == 0) break;
if (entry[e].filename[0] == 0xE5) continue;
if (entry[e].attributes == 0x0F) continue; // Skip LFN entries
if (entry[e].attributes & ATTR_VOLUME_ID) continue; // Skip volume label
// Format name
char name[13];
int n = 0;
for (int k = 0; k < 8 && entry[e].filename[k] != ' '; k++) name[n++] = entry[e].filename[k];
if (entry[e].extension[0] != ' ') {
name[n++] = '.';
for (int k = 0; k < 3 && entry[e].extension[k] != ' '; k++) name[n++] = entry[e].extension[k];
}
name[n] = 0;
// Skip . and ..
if (fs_strcmp(name, ".") == 0 || fs_strcmp(name, "..") == 0) continue;
fs_strcpy(entries[count].name, name);
entries[count].size = entry[e].file_size;
entries[count].is_directory = (entry[e].attributes & ATTR_DIRECTORY);
entries[count].start_cluster = (entry[e].start_cluster_high << 16) | entry[e].start_cluster_low;
count++;
}
current_cluster = realfs_next_cluster(vol, current_cluster);
}
kfree(cluster_buf);
return count;
}
// === Public API (Dispatch) ===
void fat32_init(void) {
// Explicitly zero out all structures for RAMFS safety
for (int i = 0; i < MAX_FILES; i++) {
files[i].used = false;
files[i].full_path[0] = 0;
files[i].filename[0] = 0;
files[i].parent_path[0] = 0;
files[i].size = 0;
files[i].attributes = 0;
files[i].start_cluster = 0;
}
// Initialize FAT table for RAMFS
for (int i = 0; i < MAX_CLUSTERS; i++) {
fat_table[i] = 0;
}
fat_table[0] = 0xFFFFFFF8;
fat_table[1] = 0xFFFFFFFF;
// Zero out cluster data
for (int i = 0; i < MAX_CLUSTERS; i++) {
for (int j = 0; j < FAT32_CLUSTER_SIZE; j++) {
cluster_data[i][j] = 0;
}
}
// Create root directory entry for RAMFS
FileEntry *root = ramfs_find_free_entry();
if (root) {
root->used = true;
root->filename[0] = 0;
fs_strcpy(root->full_path, "/");
root->start_cluster = 2;
root->size = 0;
root->attributes = ATTR_DIRECTORY;
fat_table[2] = 0xFFFFFFFF;
}
next_cluster = 3;
current_dir[0] = '/';
current_dir[1] = 0;
current_drive = 'A';
// Reset Volumes
for(int i=0; i<26; i++) volumes[i].mounted = false;
}
void fat32_set_desktop_limit(int limit) {
desktop_file_limit = limit;
}
bool fat32_change_drive(char drive) {
if (drive >= 'a' && drive <= 'z') drive -= 32;
Disk *d = disk_get_by_letter(drive);
if (d) {
current_drive = drive;
current_dir[0] = '/';
current_dir[1] = 0;
return true;
}
return false;
}
char fat32_get_current_drive(void) {
return current_drive;
}
FAT32_FileHandle* fat32_open(const char *path, const char *mode) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
const char *p = path;
char drive = parse_drive_from_path(&p);
FAT32_FileHandle *handle = NULL;
if (drive == 'A') {
char normalized[FAT32_MAX_PATH];
fat32_normalize_path(p, normalized);
handle = ramfs_open(normalized, mode);
} else {
// Real Drive
handle = realfs_open(drive, p, mode);
}
asm volatile("push %0; popfq" : : "r"(rflags));
return handle;
}
void fat32_close(FAT32_FileHandle *handle) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
if (handle && handle->valid) {
if (handle->drive != 'A' && handle->mode != 0) { // Both read and write modes for real drives
Disk *d = disk_get_by_letter(handle->drive);
if (d && handle->dir_sector != 0) {
uint8_t *buf = (uint8_t*)kmalloc(512);
if (buf) {
if (d->read_sector(d, handle->dir_sector, buf) == 0) {
FAT32_DirEntry *entry = (FAT32_DirEntry*)(buf + handle->dir_offset);
// Always update file size
entry->file_size = handle->size;
// Update start cluster if it exists
if (handle->start_cluster != 0) {
entry->start_cluster_high = (handle->start_cluster >> 16);
entry->start_cluster_low = (handle->start_cluster & 0xFFFF);
}
if (d->write_sector(d, handle->dir_sector, buf) != 0) {
}
}
kfree(buf);
}
}
}
handle->valid = false;
}
asm volatile("push %0; popfq" : : "r"(rflags));
}
int fat32_read(FAT32_FileHandle *handle, void *buffer, int size) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
if (!handle || !handle->valid || handle->mode != 0) {
asm volatile("push %0; popfq" : : "r"(rflags));
return -1;
}
int ret = 0;
if (handle->drive == 'A') {
ret = ramfs_read(handle, buffer, size);
} else {
ret = realfs_read(handle, buffer, size);
}
asm volatile("push %0; popfq" : : "r"(rflags));
return ret;
}
int fat32_write(FAT32_FileHandle *handle, const void *buffer, int size) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
if (!handle || !handle->valid || (handle->mode != 1 && handle->mode != 2)) {
asm volatile("push %0; popfq" : : "r"(rflags));
return -1;
}
int ret = 0;
if (handle->drive == 'A') {
ret = ramfs_write(handle, buffer, size);
} else {
ret = realfs_write(handle, buffer, size);
}
asm volatile("push %0; popfq" : : "r"(rflags));
return ret;
}
int fat32_seek(FAT32_FileHandle *handle, int offset, int whence) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
if (!handle || !handle->valid) {
asm volatile("push %0; popfq" : : "r"(rflags));
return -1;
}
uint32_t new_position = handle->position;
if (whence == 0) new_position = offset;
else if (whence == 1) new_position += offset;
else if (whence == 2) new_position = handle->size + offset;
if (new_position > handle->size) new_position = handle->size;
handle->position = new_position;
// Both RealFS and RAMFS must accurately re-walk their cluster chains
if (handle->drive == 'A') {
handle->cluster = handle->start_cluster;
uint32_t pos = 0;
while (pos + FAT32_CLUSTER_SIZE <= handle->position) {
uint32_t next = fat_table[handle->cluster];
if (next >= 0xFFFFFFF8) break;
handle->cluster = next;
pos += FAT32_CLUSTER_SIZE;
}
} else {
// Re-walk to find current cluster
int vol_idx = handle->drive - 'A';
FAT32_Volume *vol = &volumes[vol_idx];
uint32_t cluster_size = vol->sectors_per_cluster * 512;
handle->cluster = handle->start_cluster;
uint32_t pos = 0;
while (pos + cluster_size <= handle->position) {
uint32_t next = realfs_next_cluster(vol, handle->cluster);
if (next >= 0x0FFFFFF8) break;
handle->cluster = next;
pos += cluster_size;
}
}
asm volatile("push %0; popfq" : : "r"(rflags));
return new_position;
}
bool fat32_mkdir(const char *path) {
if (parse_drive_from_path(&path) != 'A') return false; // RAMFS only for now
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
char normalized[FAT32_MAX_PATH];
fat32_normalize_path(path, normalized);
if (ramfs_find_file(normalized)) {
asm volatile("push %0; popfq" : : "r"(rflags));
return false;
}
if (!check_desktop_limit(normalized)) {
asm volatile("push %0; popfq" : : "r"(rflags));
return false;
}
FileEntry *entry = ramfs_find_free_entry();
if (!entry) {
asm volatile("push %0; popfq" : : "r"(rflags));
return false;
}
entry->used = true;
fs_strcpy(entry->full_path, normalized);
extract_filename(normalized, entry->filename);
extract_parent_path(normalized, entry->parent_path);
entry->start_cluster = ramfs_allocate_cluster();
entry->size = 0;
entry->attributes = ATTR_DIRECTORY;
wm_notify_fs_change();
asm volatile("push %0; popfq" : : "r"(rflags));
return true;
}
bool fat32_rmdir(const char *path) {
if (parse_drive_from_path(&path) != 'A') return false;
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
char normalized[FAT32_MAX_PATH];
fat32_normalize_path(path, normalized);
FileEntry *entry = ramfs_find_file(normalized);
if (!entry || !(entry->attributes & ATTR_DIRECTORY)) {
asm volatile("push %0; popfq" : : "r"(rflags));
return false;
}
entry->used = false;
wm_notify_fs_change();
asm volatile("push %0; popfq" : : "r"(rflags));
return true;
}
bool fat32_delete(const char *path) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
const char *p = path;
char drive = parse_drive_from_path(&p);
bool result = false;
if (drive == 'A') {
// RAMFS deletion
char normalized[FAT32_MAX_PATH];
fat32_normalize_path(p, normalized);
FileEntry *entry = ramfs_find_file(normalized);
if (!entry || (entry->attributes & ATTR_DIRECTORY)) {
asm volatile("push %0; popfq" : : "r"(rflags));
return false;
}
entry->used = false;
wm_notify_fs_change();
result = true;
} else {
// Real FAT32 deletion
result = realfs_delete(drive, p);
}
asm volatile("push %0; popfq" : : "r"(rflags));
return result;
}
bool fat32_exists(const char *path) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
const char *p = path;
char drive = parse_drive_from_path(&p);
bool exists = false;
if (drive == 'A') {
char normalized[FAT32_MAX_PATH];
fat32_normalize_path(p, normalized);
exists = (ramfs_find_file(normalized) != NULL);
} else {
// RealFS check
FAT32_FileHandle *fh = realfs_open(drive, p, "r");
if (fh) {
exists = true;
fat32_close(fh);
}
}
asm volatile("push %0; popfq" : : "r"(rflags));
return exists;
}
bool fat32_rename(const char *old_path, const char *new_path) {
// Only A: supported for rename/modify
if (parse_drive_from_path(&old_path) != 'A') return false;
if (parse_drive_from_path(&new_path) != 'A') return false;
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
FileEntry *entry = ramfs_find_file(old_path); // Need to normalize inside find? yes ramfs_find calls normalize
if (!entry) { asm volatile("push %0; popfq" : : "r"(rflags)); return false; }
// Check destination
if (ramfs_find_file(new_path)) { asm volatile("push %0; popfq" : : "r"(rflags)); return false; }
size_t old_len = fs_strlen(old_path);
// Logic from original rename...
for (int i = 0; i < MAX_FILES; i++) {
if (!files[i].used) continue;
if (fs_strcmp(files[i].full_path, old_path) == 0) {
fs_strcpy(files[i].full_path, new_path);
extract_filename(new_path, files[i].filename);
extract_parent_path(new_path, files[i].parent_path);
} else if (fs_strlen(files[i].full_path) > old_len &&
fs_starts_with(files[i].full_path, old_path) &&
files[i].full_path[old_len] == '/') {
char suffix[FAT32_MAX_PATH];
fs_strcpy(suffix, files[i].full_path + old_len);
fs_strcpy(files[i].full_path, new_path);
fs_strcat(files[i].full_path, suffix);
}
if (fs_strcmp(files[i].parent_path, old_path) == 0) {
fs_strcpy(files[i].parent_path, new_path);
} else if (fs_strlen(files[i].parent_path) > old_len &&
fs_starts_with(files[i].parent_path, old_path) &&
files[i].parent_path[old_len] == '/') {
char suffix[FAT32_MAX_PATH];
fs_strcpy(suffix, files[i].parent_path + old_len);
fs_strcpy(files[i].parent_path, new_path);
fs_strcat(files[i].parent_path, suffix);
}
}
wm_notify_fs_change();
asm volatile("push %0; popfq" : : "r"(rflags));
return true;
}
bool fat32_is_directory(const char *path) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
const char *p = path;
char drive = parse_drive_from_path(&p);
bool is_dir = false;
if (drive == 'A') {
char normalized[FAT32_MAX_PATH];
fat32_normalize_path(p, normalized);
FileEntry *entry = ramfs_find_file(normalized);
is_dir = (entry && (entry->attributes & ATTR_DIRECTORY));
} else {
FAT32_FileHandle *fh = realfs_open(drive, p, "r");
if (fh) {
if (fs_strcmp(p, "/") == 0 || fs_strcmp(p, "") == 0) is_dir = true;
else {
}
fat32_close(fh);
}
}
asm volatile("push %0; popfq" : : "r"(rflags));
return is_dir;
}
int fat32_list_directory(const char *path, FAT32_FileInfo *entries, int max_entries) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
const char *p = path;
char drive = parse_drive_from_path(&p);
int count = 0;
if (drive == 'A') {
char normalized[FAT32_MAX_PATH];
fat32_normalize_path(p, normalized);
for (int i = 0; i < MAX_FILES && count < max_entries; i++) {
if (files[i].used && fs_strcmp(files[i].parent_path, normalized) == 0) {
fs_strcpy(entries[count].name, files[i].filename);
entries[count].size = files[i].size;
entries[count].is_directory = (files[i].attributes & ATTR_DIRECTORY) != 0;
entries[count].start_cluster = files[i].start_cluster;
count++;
}
}
} else {
count = realfs_list_directory(drive, p, entries, max_entries);
}
asm volatile("push %0; popfq" : : "r"(rflags));
return count;
}
bool fat32_chdir(const char *path) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
const char *p = path;
char drive = parse_drive_from_path(&p);
if (path[0] && path[1] == ':') {
if (disk_get_by_letter(drive)) {
current_drive = drive;
current_dir[0] = '/';
current_dir[1] = 0;
// If just switching drive (e.g. "B:"), return true
if (p[0] == 0) {
asm volatile("push %0; popfq" : : "r"(rflags));
return true;
}
} else {
asm volatile("push %0; popfq" : : "r"(rflags));
return false;
}
}
if (fat32_is_directory(path)) {
if (drive == 'A') {
char normalized[FAT32_MAX_PATH];
fat32_normalize_path(p, normalized);
fs_strcpy(current_dir, normalized);
} else {
fs_strcpy(current_dir, p);
if (current_dir[0] != '/') {
}
}
asm volatile("push %0; popfq" : : "r"(rflags));
return true;
}
asm volatile("push %0; popfq" : : "r"(rflags));
return false;
}
void fat32_get_current_dir(char *buffer, int size) {
uint64_t rflags;
asm volatile("pushfq; pop %0; cli" : "=r"(rflags));
int len = 0;
buffer[0] = current_drive;
buffer[1] = ':';
len = 2;
int dir_len = fs_strlen(current_dir);
if (len + dir_len >= size) dir_len = size - len - 1;
for (int i = 0; i < dir_len; i++) {
buffer[len + i] = current_dir[i];
}
buffer[len + dir_len] = 0;
asm volatile("push %0; popfq" : : "r"(rflags));
}
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