/
fat16.c
1654 lines (1344 loc) · 44.8 KB
/
fat16.c
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/**
* @section License
*
* Copyright (C) 2009, William Greiman (Arduino Fat16 Library)
* Copyright (C) 2013-2015, Mikael Patel (Cosa, Refactoring)
* Copyright (C) 2015-2017, Erik Moqvist
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* This file is part of the Simba project.
*/
#include "simba.h"
#if CONFIG_FAT16 == 1
/** Chunk size in number of bytes. */
#define BLOCK_SIZE 512
/* define fields in flags_ require sync directory entry. */
#define F_OFLAG (O_RDWR | O_APPEND | O_SYNC)
#define F_FILE_DIR_DIRTY 0x80
/** Value for byte 510 and 511 of boot block or MBR. */
#define BOOTSIG ntohs(0x55aa)
#define CACHE_FOR_READ 0 /* cache a block for read. */
#define CACHE_FOR_WRITE 1 /* cache a block and set dirty. */
/* FAT16 end of chain value used by Microsoft. */
#define EOC16 0xffff
/* Minimum value for FAT16 EOC. Use to test for EOC. */
#define EOC16_MIN 0xfff8
/* FAT32 end of chain value used by Microsoft. */
#define EOC32 0x0fffffff
/* Minimum value for FAT32 EOC. Use to test for EOC. */
#define EOC32_MIN 0x0ffffff8
/* Mask a for FAT32 entry. Entries are 28 bits. */
#define ENTRY32_MASK 0x0fffffff
/* Type name for directoryEntry. */
/* escape for name[0] = 0xe5. */
#define DIR_NAME_0XE5 0x05
/* name[0] value for entry that is free after being "deleted". */
#define DIR_NAME_DELETED 0xe5
/* name[0] value for entry that is free and no allocated entries follow. */
#define DIR_NAME_FREE 0x00
/* Test value for long name entry. */
#define DIR_ATTR_LONG_NAME 0x0f
/* Test mask for long name entry. */
#define DIR_ATTR_LONG_NAME_MASK 0x3f
/* defined attribute bits. */
#define DIR_ATTR_DEFINED_BITS 0x3f
/* Mask for file/subdirectory tests. */
#define DIR_ATTR_FILE_TYPE_MASK (DIR_ATTR_VOLUME_ID | DIR_ATTR_DIRECTORY)
#define DIR_ATTR_SKIP (DIR_ATTR_VOLUME_ID | DIR_ATTR_DIRECTORY)
/** Default date for file timestamps is 1 Jan 2000. */
#define DEFAULT_DATE (((2000 - 1980) << 9) | (1 << 5) | 1)
/** Default time for file timestamp is 1 am. */
#define DEFAULT_TIME (1 << 11)
static int is_end_of_cluster(fat_t cluster)
{
return (cluster >= 0xfff8);
}
/**
* Directory entry is part of a long name.
*/
static inline int dir_is_long_name(const struct dir_t* dir_p)
{
return ((dir_p->attributes & DIR_ATTR_LONG_NAME_MASK)
== DIR_ATTR_LONG_NAME);
}
/**
* Directory entry is for a file.
*/
static inline int dir_is_file(const struct dir_t* dir_p)
{
return ((dir_p->attributes & DIR_ATTR_FILE_TYPE_MASK) == 0);
}
/**
* Directory entry is for a subdirectory.
*/
static inline int dir_is_subdir(const struct dir_t* dir_p)
{
return ((dir_p->attributes & DIR_ATTR_FILE_TYPE_MASK)
== DIR_ATTR_DIRECTORY);
}
/**
* Directory entry is for a file or subdirectory
*/
static inline int dir_is_file_or_subdir(const struct dir_t* dir_p)
{
return ((dir_p->attributes & DIR_ATTR_VOLUME_ID) == 0);
}
/**
* Create a 8.3 file name from given name.
*/
static int make_83_name(const char* str_p,
ssize_t size,
uint8_t* name_p)
{
uint8_t c;
uint8_t n = 7;
uint8_t i;
uint8_t b;
int pos;
const char *invalid_p;
memset(name_p, ' ', 11);
i = 0;
for (pos = 0; pos < size; pos++) {
c = str_p[pos];
if (c == '.') {
if (n == 10) {
return (0);
}
n = 10;
i = 8;
} else {
/* Invalid characters in file name. */
invalid_p = "|<>^+=?/[];,*\"\\";
while ((b = *invalid_p++) != '\0') {
if (b == c) {
return (-1);
}
}
/* Invalid characters in file name. */
if (i > n || c < 0x21 || c > 0x7e) {
return (-1);
}
/* Add valid character to name. */
name_p[i++] = ((c < 'a' || c > 'z')
? c
: c + ('A' - 'a'));
}
}
return (name_p[0] == ' ');
}
/**
* Create file name from given 8.3 file name.
*/
static int make_name_from_83(char *dst_p, const char *dname_p)
{
int i, pos;
pos = 0;
/* Set name. */
for (i = 0; i < 11; i++) {
if (dname_p[i] == ' ') {
continue;
}
if (i == 8) {
dst_p[pos] = '.';
pos++;
}
dst_p[pos] = dname_p[i];
pos++;
}
dst_p[pos] = '\0';
return (0);
}
static int cache_flush(struct fat16_t *self_p)
{
struct fat16_cache_t *cache_p = &self_p->cache;
if (cache_p->dirty) {
if (self_p->write(self_p->arg_p,
cache_p->block_number,
cache_p->buffer.data) != BLOCK_SIZE) {
return (-1);
}
if (cache_p->mirror_block) {
if (self_p->write(self_p->arg_p,
cache_p->mirror_block,
cache_p->buffer.data) != BLOCK_SIZE) {
return (-1);
}
cache_p->mirror_block = 0;
}
cache_p->dirty = 0;
}
return (0);
}
static inline uint8_t block_of_cluster(uint8_t blocks_per_cluster,
uint32_t position)
{
return ((position >> 9) & (blocks_per_cluster - 1));
}
static inline uint16_t cache_data_offset(uint32_t position)
{
return (position & 0x1ff);
}
static inline void cache_set_dirty(struct fat16_cache_t *cache_p)
{
cache_p->dirty |= CACHE_FOR_WRITE;
}
static inline uint32_t data_block_lba(struct fat16_file_t *file_p,
uint8_t block_of_cluster)
{
return (file_p->fat16_p->data_start_block +
(uint32_t)((file_p->cur_cluster - 2)
* file_p->fat16_p->blocks_per_cluster) +
block_of_cluster);
}
static int cache_raw_block(struct fat16_t *self_p,
uint32_t block_number,
uint8_t action)
{
struct fat16_cache_t *cache_p = &self_p->cache;
if (cache_p->block_number != block_number) {
if (cache_flush(self_p) != 0) {
return (-1);
}
if (self_p->read(self_p->arg_p,
cache_p->buffer.data,
block_number) != BLOCK_SIZE) {
return (-1);
}
cache_p->block_number = block_number;
}
cache_p->dirty |= action;
return (0);
}
static int fat_get(struct fat16_t *self_p,
fat_t cluster,
fat_t* value)
{
uint32_t lba;
if (cluster > (self_p->cluster_count + 1)) {
return (-1);
}
lba = self_p->fat_start_block + (cluster >> 8);
if (lba != self_p->cache.block_number) {
if (cache_raw_block(self_p, lba, CACHE_FOR_READ)) {
return (-1);
}
}
*value = self_p->cache.buffer.fat[cluster & 0xff];
return (0);
}
static int fat_put(struct fat16_t *self_p, fat_t cluster, fat_t value)
{
uint32_t lba;
if (cluster < 2) {
return (-1);
}
if (cluster > (self_p->cluster_count + 1)) {
return (-1);
}
lba = self_p->fat_start_block + (cluster >> 8);
if (lba != self_p->cache.block_number) {
if (cache_raw_block(self_p, lba, CACHE_FOR_READ) != 0) {
return (-1);
}
}
self_p->cache.buffer.fat[cluster & 0xff] = value;
cache_set_dirty(&self_p->cache);
if (self_p->fat_count > 1) {
self_p->cache.mirror_block = (lba + self_p->blocks_per_fat);
}
return (0);
}
static struct dir_t* cache_dir_entry(struct fat16_t *self_p,
uint16_t block,
uint16_t index,
uint8_t action)
{
if (cache_raw_block(self_p, block + (index >> 4), action) != 0) {
return (NULL);
}
return (&self_p->cache.buffer.dir[index & 0xf]);
}
static int free_chain(struct fat16_t *self_p, fat_t cluster)
{
fat_t next;
while (1) {
if (fat_get(self_p, cluster, &next) != 0) {
return (-1);
}
if (fat_put(self_p, cluster, 0) != 0) {
return (-1);
}
if (is_end_of_cluster(next)) {
return (0);
}
cluster = next;
}
}
/**
* Write the volume start block to disk.
*/
static int write_volume_block(struct fat16_t *self_p,
uint32_t volume_start_block,
struct fbs_t *fbs_p)
{
/* Cache volume start block. */
if (cache_raw_block(self_p, volume_start_block, CACHE_FOR_WRITE) != 0) {
return (-1);
}
/* Write the boot sector to the start block. */
self_p->cache.buffer.fbs = *fbs_p;
return (cache_flush(self_p));
}
static int format_fat_blocks(struct fat16_t *self_p,
uint32_t fat_start_block,
uint32_t fat_end_block)
{
uint32_t block;
for (block = fat_start_block; block < fat_end_block; block++) {
/* Cache the next block within the fat. */
if (cache_raw_block(self_p, block, CACHE_FOR_WRITE) != 0) {
return (-1);
}
/* Format the block. */
memset(&self_p->cache.buffer, 0, sizeof(self_p->cache.buffer));
if (block == fat_start_block) {
self_p->cache.buffer.fat[0] = 0xfff8;
self_p->cache.buffer.fat[1] = 0xffff;
}
if (cache_flush(self_p) != 0) {
return (-1);
}
}
return (0);
}
static int format_root_dir_blocks(struct fat16_t *self_p,
uint32_t root_dir_start_block,
uint32_t root_dir_end_block)
{
uint32_t block;
for (block = root_dir_start_block; block < root_dir_end_block; block++) {
/* Cache the next block within the root directory. */
if (cache_raw_block(self_p, block, CACHE_FOR_WRITE) != 0) {
return (-1);
}
/* Clear the block. */
memset(&self_p->cache.buffer, 0, sizeof(self_p->cache.buffer));
/* The flush function writes to the mirrored fat block as well. */
if (cache_flush(self_p) != 0) {
return (-1);
}
}
return (0);
}
int fat16_init(struct fat16_t *self_p,
fat16_read_t read,
fat16_write_t write,
void *arg_p,
unsigned int partition)
{
ASSERTN(self_p != NULL, EINVAL);
ASSERTN(read != NULL, EINVAL);
ASSERTN(write != NULL, EINVAL);
/* Error if invalid partition. */
if (partition > 4) {
return (-EINVAL);
}
/* Initialize datastructure.*/
self_p->read = read;
self_p->write = write;
self_p->arg_p = arg_p;
self_p->partition = partition;
return (0);
}
int fat16_mount(struct fat16_t *self_p)
{
ASSERTN(self_p != NULL, EINVAL);
uint32_t total_blocks;
struct bpb_t* bpb_p;
/* Initialize the cache. */
self_p->cache.block_number = 0xffffffff;
self_p->cache.dirty = 0;
self_p->cache.mirror_block = 0;
self_p->volume_start_block = 0;
/* If part == 0 assume super floppy with FAT16 boot sector in
block zero. */
/* If part > 0 assume mbr volume with partition table. */
if (self_p->partition > 0) {
if (cache_raw_block(self_p,
self_p->volume_start_block,
CACHE_FOR_READ) != 0) {
return (-1);
}
self_p->volume_start_block =
self_p->cache.buffer.mbr.part[self_p->partition - 1].first_sector;
}
if (cache_raw_block(self_p, self_p->volume_start_block, CACHE_FOR_READ) != 0) {
return (-1);
}
/* Check boot block signature. */
if (self_p->cache.buffer.fbs.boot_sector_sig != BOOTSIG) {
return (-1);
}
bpb_p = &self_p->cache.buffer.fbs.bpb;
self_p->fat_count = bpb_p->fat_count;
self_p->blocks_per_cluster = bpb_p->sectors_per_cluster;
self_p->blocks_per_fat = bpb_p->sectors_per_fat;
self_p->root_dir_entry_count = bpb_p->root_dir_entry_count;
self_p->fat_start_block = (self_p->volume_start_block
+ bpb_p->reserved_sector_count);
self_p->root_dir_start_block =
(self_p->fat_start_block
+ bpb_p->fat_count * bpb_p->sectors_per_fat);
self_p->data_start_block =
(self_p->root_dir_start_block
+ ((32 * bpb_p->root_dir_entry_count + 511) / 512));
total_blocks = (bpb_p->total_sectors_small
? bpb_p->total_sectors_small
: bpb_p->total_sectors_large);
self_p->cluster_count =
((total_blocks - (self_p->data_start_block - self_p->volume_start_block))
/ bpb_p->sectors_per_cluster);
/* Check valid FAT16 volume. */
if ((bpb_p->bytes_per_sector != 512) /* Only allow 512 byte
blocks. */
|| (bpb_p->sectors_per_fat == 0) /* Zero for FAT32. */
|| (self_p->cluster_count < 4085) /* FAT12 if true. */
|| (total_blocks > 0x800000) /* Max size for FAT16
volume. */
|| (bpb_p->reserved_sector_count == 0) /* Invalid volume. */
|| (bpb_p->fat_count == 0) /* Invalid volume. */
|| (bpb_p->sectors_per_fat < (self_p->cluster_count >> 8))
|| (bpb_p->sectors_per_cluster == 0)
|| (bpb_p->sectors_per_cluster
& (bpb_p->sectors_per_cluster - 1))) {
return (-1);
}
return (0);
}
int fat16_unmount(struct fat16_t *self_p)
{
ASSERTN(self_p != NULL, EINVAL);
return (cache_flush(self_p));
}
int fat16_format(struct fat16_t *self_p)
{
ASSERTN(self_p != NULL, EINVAL);
struct fbs_t fbs;
uint32_t volume_start_block;
uint32_t fat_start_block;
uint32_t blocks_per_fat;
uint32_t root_dir_start_block;
uint32_t root_dir_block_count;
/* Initialize the cache. */
self_p->cache.block_number = 0xffffffff;
self_p->cache.dirty = 0;
self_p->cache.mirror_block = 0;
volume_start_block = 0;
/* Initiate the boot sector. */
fbs.jmp_to_boot_code[0] = 0xeb;
fbs.jmp_to_boot_code[1] = 0x3c;
fbs.jmp_to_boot_code[2] = 0x90;
strcpy(fbs.oem_name, "simba");
fbs.bpb.bytes_per_sector = 512;
fbs.bpb.sectors_per_cluster = 4;
fbs.bpb.reserved_sector_count = 1;
fbs.bpb.fat_count = 2;
fbs.bpb.root_dir_entry_count = 512;
fbs.bpb.total_sectors_small = 32768;
fbs.bpb.media_type = 248;
fbs.bpb.sectors_per_fat = 32;
fbs.bpb.sectors_per_track = 32;
fbs.bpb.head_count = 64;
fbs.bpb.hiddden_sectors = 0;
fbs.bpb.total_sectors_large = 0;
fbs.drive_number = 128;
fbs.reserved1 = 0;
fbs.boot_signature = 41;
fbs.volume_serial_number = 1817095464;
memcpy(fbs.volume_label, "NO NAME ", sizeof(fbs.volume_label));
memcpy(fbs.file_system_type, "FAT16 ", sizeof(fbs.file_system_type));
memset(fbs.boot_code, 0, sizeof(fbs.boot_code));
fbs.boot_sector_sig = BOOTSIG;
fat_start_block = (volume_start_block + fbs.bpb.reserved_sector_count);
blocks_per_fat = fbs.bpb.sectors_per_fat;
root_dir_start_block = (fat_start_block
+ fbs.bpb.fat_count * fbs.bpb.sectors_per_fat);
root_dir_block_count = (fbs.bpb.root_dir_entry_count
/ (512 / sizeof(struct dir_t)));
if (write_volume_block(self_p,
volume_start_block,
&fbs) != 0) {
return (-1);
}
if (format_fat_blocks(self_p,
fat_start_block,
fat_start_block + blocks_per_fat) != 0) {
return (-1);
}
if (fbs.bpb.fat_count > 1) {
if (format_fat_blocks(self_p,
fat_start_block + blocks_per_fat,
fat_start_block + 2 * blocks_per_fat) != 0) {
return (-1);
}
}
if (format_root_dir_blocks(self_p,
root_dir_start_block,
root_dir_start_block + root_dir_block_count) != 0) {
return (-1);
}
return (0);
}
int fat16_print(struct fat16_t *self_p, void *chan_p)
{
ASSERTN(self_p != NULL, EINVAL);
ASSERTN(chan_p != NULL, EINVAL);
std_fprintf(chan_p,
FSTR("fat_count = %u\r\n"
"blocks_per_cluster = %u\r\n"
"root_dir_entry_count = %u\r\n"
"blocks_per_fat = %u\r\n"
"cluster_count = %u\r\n"
"volume_start_block = %lu\r\n"
"fat_start_block = %lu\r\n"
"root_dir_start_block = %lu\r\n"
"data_start_block = %lu\r\n"),
(unsigned int)self_p->fat_count,
(unsigned int)self_p->blocks_per_cluster,
(unsigned int)self_p->root_dir_entry_count,
(unsigned int)self_p->blocks_per_fat,
(unsigned int)self_p->cluster_count,
(unsigned long)self_p->volume_start_block,
(unsigned long)self_p->fat_start_block,
(unsigned long)self_p->root_dir_start_block,
(unsigned long)self_p->data_start_block);
return (0);
}
static int add_cluster(struct fat16_file_t *file_p)
{
/* Start search after last cluster of file or at cluster two in FAT. */
fat_t free_cluster = file_p->cur_cluster ? file_p->cur_cluster : 1;
fat_t value;
fat_t i;
fat_t cluster_count = file_p->fat16_p->cluster_count;
for (i = 0; ; i++) {
/* Return no free clusters. */
if (i >= cluster_count) {
return (-1);
}
/* Fat has cluster_count + 2 entries. */
if (free_cluster > cluster_count) {
free_cluster = 1;
}
free_cluster++;
if (fat_get(file_p->fat16_p, free_cluster, &value) != 0) {
return (-1);
}
if (value == 0) {
break;
}
}
/* Mark cluster allocated. */
if (fat_put(file_p->fat16_p, free_cluster, EOC16) != 0) {
return (-1);
}
if (file_p->cur_cluster != 0) {
/* Link cluster to chain. */
if (fat_put(file_p->fat16_p, file_p->cur_cluster, free_cluster) != 0) {
return (-1);
}
} else {
/* first cluster of file so update directory entry. */
file_p->flags |= F_FILE_DIR_DIRTY;
file_p->first_cluster = free_cluster;
}
file_p->cur_cluster = free_cluster;
return (0);
}
static int dir_init(struct dir_t *dir_p,
uint8_t *name_p,
uint8_t attributes)
{
/* Initialize as empty file. */
memset(dir_p, 0, sizeof(*dir_p));
memcpy(dir_p->name, name_p, 11);
dir_p->attributes = attributes;
/* Set timestamps with user function or use default date/time. */
/* if (dateTime) { */
/* dateTime(&dir_p->creationDate, &dir_p->creationTime); */
/* } else { */
dir_p->creation_date = DEFAULT_DATE;
dir_p->creation_time = DEFAULT_TIME;
/* } */
dir_p->last_access_date = dir_p->creation_date;
dir_p->last_write_date = dir_p->creation_date;
dir_p->last_write_time = dir_p->creation_time;
return (0);
}
static int get_dir_at_index_in_root(struct fat16_t *self_p,
int16_t index,
struct dir_t *dir_p)
{
int dir_entries_per_block;
int block;
struct dir_t *d_p;
dir_entries_per_block = (512 / sizeof(struct dir_t));
block = (self_p->root_dir_start_block + (index / dir_entries_per_block));
index = (index % dir_entries_per_block);
if (!(d_p = cache_dir_entry(self_p,
block,
index,
CACHE_FOR_READ))) {
return (-1);
}
/* Copy the directory entry to output variable. */
*dir_p = *d_p;
return (0);
}
/**
* Try to open directory entry of given name within range of blocks.
*
* @param[in] name_p Name of the file or directory to look for.
* @param[out] block_p Block index of the block containing name_p, or
* the first free block if the name was not found.
* @param[out] index_p Index within the block where the name matched,
* or the first free index in the block.
* @param[in] start_block Block to search from.
* @param[in] end_block Block to search to.
*
* @return true(1) if a directory entry for given name was found,
* false(0) if the name was not found and the block_p and
* index_p holds the address of an empty slot, otherwise
* negative error code.
*/
static int dir_open_in_blocks(struct fat16_t *self_p,
const uint8_t *name_p,
int16_t *block_p,
int16_t *index_p,
int start_block,
int end_block)
{
int16_t block;
int16_t index;
int dir_entries_per_block;
struct dir_t *dir_p;
dir_entries_per_block = (512 / sizeof(*dir_p));
for (block = start_block; block < end_block; block++) {
for (index = 0; index < dir_entries_per_block; index++) {
if (!(dir_p = cache_dir_entry(self_p,
block,
index,
CACHE_FOR_READ))) {
return (-1);
}
if ((dir_p->name[0] == DIR_NAME_FREE)
|| (dir_p->name[0] == DIR_NAME_DELETED)) {
/* Remember first empty slot */
if (*index_p < 0) {
*block_p = block;
*index_p = index;
}
/* Done if no entries follow. */
if (dir_p->name[0] == DIR_NAME_FREE) {
return (0);
}
} else if (memcmp(name_p, dir_p->name, 11) == 0) {
/* Existing file. */
*block_p = block;
*index_p = index;
return (1);
}
}
}
return (0);
}
/**
* Open directory with given name in the root folder.
*
* @param[out] index_p If true(1) is returned this is the index of an
* existing file. If false(0) is returned this is
* the index of the first empty directory
* entry. Otherwise ignore this value.
*
* @return zero(0) or negative error code.
*/
static int dir_open_in_root(struct fat16_t *self_p,
const uint8_t *name_p,
int16_t *block_p,
int16_t *index_p)
{
int root_dir_block_count;
int dir_entries_per_block;
*index_p = -1; /* index of empty slot. */
dir_entries_per_block = (512 / sizeof(struct dir_t));
root_dir_block_count = (self_p->root_dir_entry_count / dir_entries_per_block);
/* Search for the file in the root directory. */
return (dir_open_in_blocks(self_p,
name_p,
block_p,
index_p,
self_p->root_dir_start_block,
self_p->root_dir_start_block + root_dir_block_count));
}
/**
* Open directory with given name in given sub folder.
*
* @param[out] index_p If true(1) is returned this is the index of an
* existing file. If false(0) is returned this is
* the index of the first empty directory
* entry. Otherwise ignore this value.
*
* @return zero(0) or negative error code.
*/
static int dir_open_in_subdir(struct fat16_t *self_p,
const uint8_t *name_p,
int16_t *block_p,
int16_t *index_p)
{
fat_t cluster;
int start_block;
struct dir_t *dir_p;
int res = -1;
/* Cache the parent directory. */
if (!(dir_p = cache_dir_entry(self_p,
*block_p,
*index_p,
CACHE_FOR_WRITE))) {
return (-1);
}
*index_p = -1; /* index of empty slot. */
/* Search for the file in the subdirectory. Iterate over clusters
allocated by this folder. */
cluster = dir_p->first_cluster_low;
do {
start_block = (self_p->data_start_block
+ ((cluster - 2) * self_p->blocks_per_cluster));
if ((res = dir_open_in_blocks(self_p,
name_p,
block_p,
index_p,
start_block,
start_block + self_p->blocks_per_cluster)) < 0) {
return (-1);
}
if (fat_get(self_p, cluster, &cluster) != 0) {
return (-1);
}
} while (!is_end_of_cluster(cluster));
return (res);
}
/**
* Get name before first '/' or end of path.
*
* @param[in,out] path_p Path to parse. Is set to NULL when the
* function returns if the name is the last part
* of the path.
*
* @return zero(0) or negative error code.
*/
static int get_next_name(const char **path_p, uint8_t *name_p)
{
const char *begin_p = *path_p;
size_t size;
/* Forward to end of name. */
while ((**path_p != '/') && (**path_p != '\0')) {
(*path_p)++;
}
size = (*path_p - begin_p);
/* Check valid 8.3 file name. */
if (make_83_name(begin_p, size, name_p) != 0) {
return (-1);
}
if (**path_p == '/') {
(*path_p)++;
}
if (**path_p == '\0') {
*path_p = NULL;
}
return (0);
}
static int dir_open(struct fat16_t *self_p,
const char *path_p,
int oflag,
uint8_t attributes,
int16_t *block_p,
int16_t *index_p)
{
uint8_t dname[11]; /* name formated for dir entry. */
struct dir_t *dir_p = NULL; /* pointer to cached dir entry. */
int res;
int depth = 0;
int16_t parent_block = -1;
int16_t parent_index = -1;
do {
if (get_next_name(&path_p, dname) != 0) {
return (-1);
}
if (depth == 0) {
/* Search for the name in the root folder. */
res = dir_open_in_root(self_p, dname, block_p, index_p);
} else {
/* Search for the name in a subfolder. */
res = dir_open_in_subdir(self_p, dname, block_p, index_p);
}
if (res < 0) {
return (res);
} else if (path_p != NULL) {
if (res == 0) {
/* Containing directory of next part of path was not found. */
return (-1);
} else {
/* Potentially parent directory. */
parent_block = *block_p;
parent_index = *index_p;
}
}
depth++;
} while (path_p != NULL);
/* The file or directory already exists. */
if (res == 1) {
/* Don't open existing file if O_CREAT and O_EXCL. */
if ((oflag & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL)) {
return (-1);
}
return (0);
}
/* Error if directory is full. */
if (*index_p < 0) {
return (-1);
}
/* Only create file if O_CREAT and O_WRITE. */
if ((oflag & (O_CREAT | O_WRITE)) != (O_CREAT | O_WRITE)) {
return (-1);