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emfat/project/emfat.c

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/*
* The MIT License (MIT)
*
* Copyright (c) 2015 by Sergey Fetisov <fsenok@gmail.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/*
* version: 1.0 (4.01.2015)
*/
#include "emfat.h"
#ifdef __cplusplus
extern "C" {
#endif
#define SECT 512
#define CLUST 4096
#define SECT_PER_CLUST (CLUST / SECT)
#define SIZE_TO_NSECT(s) ((s) == 0 ? 1 : ((s) + SECT - 1) / SECT)
#define SIZE_TO_NCLUST(s) ((s) == 0 ? 1 : ((s) + CLUST - 1) / CLUST)
#define CLUST_FREE 0x00000000
#define CLUST_RESERVED 0x00000001
#define CLUST_BAD 0x0FFFFFF7
#define CLUST_ROOT_END 0X0FFFFFF8
#define CLUST_EOF 0x0FFFFFFF
#define MAX_DIR_ENTRY_CNT 16
#define FILE_SYS_TYPE_OFF 82
#define BYTES_PER_SEC_OFF 11
#define SEC_PER_CLUS_OFF 13
#define RES_SEC_CNT_OFF 14
#define FAT_CNT_OFF 16
#define TOT_SEC_CNT_OFF 32
#define SEC_PER_FAT 36
#define ROOT_DIR_STRT_CLUS_OFF 44
#define FS_INFOSECTOR_OFF 48
#define BACKUP_BOOT_SEC_OFF 50
#define NXT_FREE_CLUS_OFF 492
#define FILE_SYS_TYPE_LENGTH 8
#define SHRT_FILE_NAME_LEN 11
#define STRT_CLUS_LOW_OFF 26
#define STRT_CLUS_HIGH_OFF 20
#define FILE_SIZE_OFF 28
#define ATTR_OFF 11
#define FILE_STAT_LEN 21
#define CHECK_SUM_OFF 13
#define FILE_NAME_SHRT_LEN 8
#define FILE_NAME_EXTN_LEN 3
#define LONG_FILE_NAME_LEN 255
#define LOW_CLUSWORD_MASK 0x0000FFFF
#define HIGH_CLUSWORD_MASK 0xFFFF0000
#define LONG_FNAME_MASK 0x0F
#define LAST_ORD_FIELD_SEQ 0x40
#define LFN_END_MARK 0xFFFF
#define LFN_TERM_MARK 0x0000
#define LFN_FIRST_OFF 0x01
#define LFN_SIXTH_OFF 0x0E
#define LFN_TWELVETH_OFF 0x1C
#define LFN_FIRST_SET_CNT 5
#define LFN_SEC_SET_CNT 6
#define LFN_THIRD_SET_CNT 2
#define LFN_FIRST_SET_LEN 10
#define LFN_SEC_SET_LEN 12
#define LFN_THIRD_SET_LEN 4
#define LFN_EMPTY_LEN 2
#define LFN_LEN_PER_ENTRY 13
#define FNAME_EXTN_SEP_OFF 6
#define FNAME_SEQ_NUM_OFF 7
#define BYTES_PER_CLUSTER_ENTRY 4
#define DIR_ENTRY_LEN 32
#define VOL_ID_LEN 4
#define VOL_LABEL_LEN 11
#define RESERV_LEN 12
#define FS_VER_LEN 2
#define OEM_NAME_LEN 8
#define JUMP_INS_LEN 3
#define MAX_FAT_CNT 2
#define SPACE_VAL 32
#define FILE_READ 0x01
#define FILE_WRITE 0X02
#define FILE_CREATE_NEW 0x04
#define FILE_CREATE_ALWAYS 0x08
#define FILE_APPEND 0x10
#define ATTR_READ 0x01
#define ATTR_HIDDEN 0x02
#define ATTR_SYSTEM 0x04
#define ATTR_VOL_LABEL 0x08
#define ATTR_DIR 0x10
#define ATTR_ARCHIVE 0x20
#define ATTR_LONG_FNAME 0x0F
#define FREE_DIR_ENTRY 0x00
#define DEL_DIR_ENTRY 0xE5
#define DOT_DIR_ENTRY 0x2E
#define ASCII_DIFF 32
#define FILE_SEEK_SET 0
#define FILE_SEEK_CUR 1
#define FILE_SEEK_END 2
#define DELIMITER '/'
#define EXTN_DELIMITER '.'
#define TILDE '~'
#define FULL_SHRT_NAME_LEN 13
#pragma pack(push, 1)
typedef struct
{
uint8_t status; // 0x80 for bootable, 0x00 for not bootable, anything else for invalid
uint8_t StartAddrHead; // head address of start of partition
uint16_t StartAddrCylSec; // (AddrCylSec & 0x3F) for sector, (AddrCylSec & 0x3FF) for cylendar
uint8_t PartType;
uint8_t EndAddrHead; // head address of start of partition
uint16_t EndAddrCylSec; // (AddrCylSec & 0x3F) for sector, (AddrCylSec & 0x3FF) for cylendar
uint32_t StartLBA; // linear address of first sector in partition. Multiply by sector size (usually 512) for real offset
uint32_t EndLBA; // linear address of last sector in partition. Multiply by sector size (usually 512) for real offset
} mbr_part_t;
typedef struct
{
uint8_t Code[440];
uint32_t DiskSig; //This is optional
uint16_t Reserved; //Usually 0x0000
mbr_part_t PartTable[4];
uint8_t BootSignature[2]; //0x55 0xAA for bootable
} mbr_t;
typedef struct
{
uint8_t jump[JUMP_INS_LEN];
uint8_t OEM_name[OEM_NAME_LEN];
uint16_t bytes_per_sec;
uint8_t sec_per_clus;
uint16_t reserved_sec_cnt;
uint8_t fat_cnt;
uint16_t root_dir_max_cnt;
uint16_t tot_sectors;
uint8_t media_desc;
uint16_t sec_per_fat_fat16;
uint16_t sec_per_track;
uint16_t number_of_heads;
uint32_t hidden_sec_cnt;
uint32_t tol_sector_cnt;
uint32_t sectors_per_fat;
uint16_t ext_flags;
uint8_t fs_version[FS_VER_LEN];
uint32_t root_dir_strt_cluster;
uint16_t fs_info_sector;
uint16_t backup_boot_sector;
uint8_t reserved[RESERV_LEN];
uint8_t drive_number;
uint8_t reserved1;
uint8_t boot_sig;
uint8_t volume_id[VOL_ID_LEN];
uint8_t volume_label[VOL_LABEL_LEN];
uint8_t file_system_type[FILE_SYS_TYPE_LENGTH];
} boot_sector;
typedef struct
{
uint8_t name[FILE_NAME_SHRT_LEN];
uint8_t extn[FILE_NAME_EXTN_LEN];
uint8_t attr;
uint8_t reserved;
uint8_t crt_time_tenth;
uint16_t crt_time;
uint16_t crt_date;
uint16_t lst_access_date;
uint16_t strt_clus_hword;
uint16_t lst_mod_time;
uint16_t lst_mod_date;
uint16_t strt_clus_lword;
uint32_t size;
} dir_entry;
typedef struct
{
uint8_t ord_field;
uint8_t fname0_4[LFN_FIRST_SET_LEN];
uint8_t flag;
uint8_t reserved;
uint8_t chksum;
uint8_t fname6_11[LFN_SEC_SET_LEN];
uint8_t empty[LFN_EMPTY_LEN];
uint8_t fname12_13[LFN_THIRD_SET_LEN];
} lfn_entry;
#pragma pack(pop)
bool emfat_init_entries(emfat_entry_t *entries)
{
emfat_entry_t *e;
int i, n;
e = &entries[0];
if (e->level != 0 || !e->dir || e->name == NULL) return false;
e->priv.top = NULL;
e->priv.next = NULL;
e->priv.sub = NULL;
e->priv.num_subentry = 0;
n = 0;
for (i = 1; entries[i].name != NULL; i++)
{
entries[i].priv.top = NULL;
entries[i].priv.next = NULL;
entries[i].priv.sub = NULL;
entries[i].priv.num_subentry = 0;
if (entries[i].level == n - 1)
{
if (n == 0) return false;
e = e->priv.top;
n--;
}
if (entries[i].level == n + 1)
{
if (!e->dir) return false;
e->priv.sub = &entries[i];
entries[i].priv.top = e;
e = &entries[i];
n++;
continue;
}
if (entries[i].level == n)
{
if (n == 0) return false;
e->priv.top->priv.num_subentry++;
entries[i].priv.top = e->priv.top;
e->priv.next = &entries[i];
e = &entries[i];
continue;
}
return false;
}
return true;
}
bool emfat_init(emfat_t *emfat, const char *label, emfat_entry_t *entries)
{
uint32_t sect_per_fat;
uint32_t clust;
emfat_entry_t *e;
int i;
if (emfat == NULL || label == NULL || entries == NULL)
return false;
if (!emfat_init_entries(entries))
return false;
clust = 2;
for (i = 0; entries[i].name != NULL; i++)
{
e = &entries[i];
if (e->dir)
{
e->curr_size = 0;
e->priv.first_clust = clust;
e->priv.last_clust = clust + SIZE_TO_NCLUST(e->priv.num_subentry * sizeof(dir_entry)) - 1;
e->priv.last_reserved = e->priv.last_clust;
}
else
{
e->priv.first_clust = clust;
e->priv.last_clust = e->priv.first_clust + SIZE_TO_NCLUST(entries[i].curr_size) - 1;
e->priv.last_reserved = e->priv.first_clust + SIZE_TO_NCLUST(entries[i].max_size) - 1;
}
clust = e->priv.last_reserved + 1;
}
clust -= 2;
emfat->vol_label = label;
emfat->priv.num_entries = i;
emfat->priv.boot_sect = 62;
emfat->priv.fat1_sect = emfat->priv.boot_sect + 1;
emfat->priv.num_clust = clust;
sect_per_fat = SIZE_TO_NSECT((uint64_t)emfat->priv.num_clust * 4);
emfat->priv.fat2_sect = emfat->priv.fat1_sect + sect_per_fat;
emfat->priv.root_sect = emfat->priv.fat2_sect + sect_per_fat;
emfat->priv.entries = entries;
emfat->priv.last_entry = entries;
emfat->num_sectors = clust * 8 + emfat->priv.root_sect;
emfat->vol_size = (uint64_t)emfat->num_sectors * SECT;
return true;
}
/*
void lba_to_chs(uint32_t lba, uint8_t *cl, uint8_t *ch, uint8_t *dh)
{
int cylinder, head, sector;
int sectors = 63, heads = 255, cylinders = 1024;
sector = lba % sectors + 1;
head = (lba / sectors) % heads;
cylinder = lba / (sectors * heads);
if (cylinder >= cylinders)
{
*cl = *ch = *dh = 0xff;
return;
}
*cl = sector | ((cylinder & 0x300) >> 2);
*ch = cylinder & 0xFF;
*dh = head;
}
*/
void read_mbr_sector(const emfat_t *emfat, uint8_t *sect)
{
mbr_t *mbr;
memset(sect, 0, SECT);
mbr = (mbr_t *)sect;
mbr->DiskSig = 0;
mbr->Reserved = 0;
mbr->PartTable[0].status = 0x00;
mbr->PartTable[0].StartAddrHead = 0;
mbr->PartTable[0].StartAddrCylSec = 0;
mbr->PartTable[0].PartType = 0x0C;
mbr->PartTable[0].EndAddrHead = 0;
mbr->PartTable[0].EndAddrCylSec = 0;
mbr->PartTable[0].StartLBA = emfat->priv.boot_sect;
mbr->PartTable[0].EndLBA = emfat->num_sectors - emfat->priv.boot_sect;
// ((emfat->num_sectors + SECT_PER_CLUST - 1) / SECT_PER_CLUST) * SECT_PER_CLUST;
mbr->BootSignature[0] = 0x55;
mbr->BootSignature[1] = 0xAA;
}
void read_boot_sector(const emfat_t *emfat, uint8_t *sect)
{
boot_sector *bs;
memset(sect, 0, SECT);
bs = (boot_sector *)sect;
bs->jump[0] = 0xEB;
bs->jump[1] = 0x58;
bs->jump[2] = 0x90;
memcpy(bs->OEM_name, "MSDOS5.0", 8);
bs->bytes_per_sec = SECT;
bs->sec_per_clus = 8;
bs->reserved_sec_cnt = 1;
bs->fat_cnt = 2;
bs->root_dir_max_cnt = 0;
bs->tot_sectors = 0;
bs->media_desc = 0xF8;
bs->sec_per_fat_fat16 = 0;
bs->sec_per_track = 63;
bs->number_of_heads = 0xFF;
bs->hidden_sec_cnt = 62;
bs->tol_sector_cnt = emfat->priv.root_sect + emfat->priv.num_clust * 8;
bs->sectors_per_fat = emfat->priv.fat2_sect - emfat->priv.fat1_sect;
bs->ext_flags = 0;
bs->fs_version[0] = 0;
bs->fs_version[1] = 0;
bs->root_dir_strt_cluster = 2;
bs->fs_info_sector = 0;
bs->backup_boot_sector = 0;
bs->drive_number = 128;
bs->boot_sig = 0x29;
bs->volume_id[0] = 148;
bs->volume_id[1] = 14;
bs->volume_id[2] = 13;
bs->volume_id[3] = 8;
memcpy(bs->volume_label, "NO NAME ", 12);
memcpy(bs->file_system_type, "FAT32 ", 8);
sect[SECT - 2] = 0x55;
sect[SECT - 1] = 0xAA;
}
#define IS_CLUST_OF(clust, entry) ((clust) >= (entry)->priv.first_clust && (clust) <= (entry)->priv.last_reserved)
emfat_entry_t *find_entry(const emfat_t *emfat, uint32_t clust, emfat_entry_t *nearest)
{
if (nearest == NULL)
nearest = emfat->priv.entries;
if (nearest->priv.first_clust > clust)
while (nearest >= emfat->priv.entries) // backward finding
{
if (IS_CLUST_OF(clust, nearest))
return nearest;
nearest--;
}
else
while (nearest->name != NULL) // forward finding
{
if (IS_CLUST_OF(clust, nearest))
return nearest;
nearest++;
}
return NULL;
}
void read_fat_sector(emfat_t *emfat, uint8_t *sect, uint32_t index)
{
emfat_entry_t *le;
uint32_t *values;
uint32_t count;
uint32_t curr;
values = (uint32_t *)sect;
curr = index * 128;
count = 128;
if (curr == 0)
{
*values++ = CLUST_ROOT_END;
*values++ = 0xFFFFFFFF;
count -= 2;
curr += 2;
}
le = emfat->priv.last_entry;
while (count != 0)
{
if (!IS_CLUST_OF(curr, le))
{
le = find_entry(emfat, curr, le);
if (le == NULL)
{
le = emfat->priv.last_entry;
*values = CLUST_RESERVED;
values++;
count--;
curr++;
continue;
}
}
if (le->dir)
{
if (curr == le->priv.last_clust)
*values = CLUST_EOF; else
*values = curr + 1;
}
else
{
if (curr == le->priv.last_clust)
*values = CLUST_EOF; else
if (curr > le->priv.last_clust)
*values = CLUST_FREE; else
*values = curr + 1;
}
values++;
count--;
curr++;
}
emfat->priv.last_entry = le;
}
void fill_entry(dir_entry *entry, const char *name, uint8_t attr, uint32_t clust, uint32_t size)
{
int i, l, l1, l2;
int dot_pos;
memset(entry, 0, sizeof(dir_entry));
l = strlen(name);
dot_pos = -1;
if ((attr & ATTR_DIR) == 0)
for (i = l - 1; i >= 0; i--)
if (name[i] == '.')
{
dot_pos = i;
break;
}
if (dot_pos == -1)
{
l1 = l > FILE_NAME_SHRT_LEN ? FILE_NAME_SHRT_LEN : l;
l2 = 0;
}
else
{
l1 = dot_pos;
l1 = l1 > FILE_NAME_SHRT_LEN ? FILE_NAME_SHRT_LEN : l1;
l2 = l - dot_pos - 1;
l2 = l2 > FILE_NAME_EXTN_LEN ? FILE_NAME_EXTN_LEN : l2;
}
memset(entry->name, ' ', FILE_NAME_SHRT_LEN + FILE_NAME_EXTN_LEN);
memcpy(entry->name, name, l1);
memcpy(entry->extn, name + dot_pos + 1, l2);
for (i = 0; i < FILE_NAME_SHRT_LEN + FILE_NAME_EXTN_LEN; i++)
if (entry->name[i] >= 'a' && entry->name[i] <= 'z')
entry->name[i] -= 0x20;
entry->attr = attr;
entry->reserved = 24;
entry->strt_clus_hword = clust >> 16;
entry->strt_clus_lword = clust;
entry->size = size;
return;
}
void fill_dir_sector(emfat_t *emfat, uint8_t *data, emfat_entry_t *entry, uint32_t rel_sect)
{
dir_entry *de;
uint32_t avail;
memset(data, 0, SECT);
de = (dir_entry *)data;
avail = SECT;
if (rel_sect == 0)
// 1. first sector of directory
{
if (entry->priv.top == NULL)
{
fill_entry(de++, emfat->vol_label, ATTR_VOL_LABEL, 0, 0);
avail -= sizeof(dir_entry);
}
else
{
fill_entry(de++, ".", ATTR_DIR | ATTR_READ, entry->priv.first_clust, 0);
fill_entry(de++, "..", ATTR_DIR | ATTR_READ, entry->priv.top->priv.first_clust, 0);
avail -= sizeof(dir_entry) * 2;
}
entry = entry->priv.sub;
}
else
// 2. not a first sector
{
int n;
n = rel_sect * (SECT / sizeof(dir_entry));
n -= entry->priv.top == NULL ? 1 : 2;
entry = entry->priv.sub;
while (n > 0 && entry != NULL)
{
entry = entry->priv.next;
n--;
}
}
while (entry != NULL && avail >= sizeof(dir_entry))
{
if (entry->dir)
fill_entry(de++, entry->name, ATTR_DIR | ATTR_READ, entry->priv.first_clust, 0); else
fill_entry(de++, entry->name, ATTR_ARCHIVE | ATTR_READ, entry->priv.first_clust, entry->curr_size);
entry = entry->priv.next;
avail -= sizeof(dir_entry);
}
}
void read_data_sector(emfat_t *emfat, uint8_t *data, uint32_t rel_sect)
{
emfat_entry_t *le;
uint32_t cluster;
cluster = rel_sect / 8 + 2;
rel_sect = rel_sect % 8;
le = emfat->priv.last_entry;
if (!IS_CLUST_OF(cluster, le))
{
le = find_entry(emfat, cluster, le);
if (le == NULL)
{
int i;
for (i = 0; i < SECT / 4; i++)
((uint32_t *)data)[i] = 0xEFBEADDE;
return;
}
emfat->priv.last_entry = le;
}
if (le->dir)
{
fill_dir_sector(emfat, data, le, rel_sect);
return;
}
if (le->readcb == NULL)
memset(data, 0, SECT);
else
{
uint32_t offset = cluster - le->priv.first_clust;
offset = offset * CLUST + rel_sect * SECT;
le->readcb(data, SECT, offset + le->offset, le->user_data);
}
return;
}
void emfat_read(emfat_t *emfat, uint8_t *data, uint32_t sector, int num_sectors)
{
while (num_sectors > 0)
{
if (sector >= emfat->priv.root_sect)
read_data_sector(emfat, data, sector - emfat->priv.root_sect);
else
if (sector == 0)
read_mbr_sector(emfat, data);
else
if (sector == emfat->priv.boot_sect)
read_boot_sector(emfat, data);
else
if (sector >= emfat->priv.fat1_sect && sector < emfat->priv.fat2_sect)
read_fat_sector(emfat, data, sector - emfat->priv.fat1_sect);
else
if (sector >= emfat->priv.fat2_sect && sector < emfat->priv.root_sect)
read_fat_sector(emfat, data, sector - emfat->priv.fat2_sect);
else
memset(data, 0, SECT);
data += SECT;
num_sectors--;
sector++;
}
}
void write_data_sector(emfat_t *emfat, const uint8_t *data, uint32_t rel_sect)
{
emfat_entry_t *le;
uint32_t cluster;
cluster = rel_sect / 8 + 2;
rel_sect = rel_sect % 8;
le = emfat->priv.last_entry;
if (!IS_CLUST_OF(cluster, le))
{
le = find_entry(emfat, cluster, le);
if (le == NULL) return;
emfat->priv.last_entry = le;
}
if (le->dir)
{
// TODO: handle changing a filesize
return;
}
if (le->writecb != NULL)
le->writecb(data, SECT, rel_sect * SECT + le->offset, le->user_data);
}
void write_fat_sector(emfat_t *emfat, const uint8_t *data, uint32_t rel_sect)
{
}
void emfat_write(emfat_t *emfat, const uint8_t *data, uint32_t sector, int num_sectors)
{
while (num_sectors > 0)
{
if (sector >= emfat->priv.root_sect)
write_data_sector(emfat, data, sector - emfat->priv.root_sect);
else
if (sector >= emfat->priv.fat1_sect && sector < emfat->priv.fat2_sect)
write_fat_sector(emfat, data, sector - emfat->priv.fat1_sect);
else
if (sector >= emfat->priv.fat2_sect && sector < emfat->priv.root_sect)
write_fat_sector(emfat, data, sector - emfat->priv.fat2_sect);
data += SECT;
num_sectors--;
sector++;
}
}
#ifdef __cplusplus
}
#endif
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