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6869b14694
third_party_littlefs/lfs.c
Christopher Haster 6869b14694 Fixed memory leak for lookahead buffer
2017-05-08 00:38:20 -05:00

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/*
* The little filesystem
*
* Copyright (c) 2017 Christopher Haster
* Distributed under the MIT license
*/
#include "lfs.h"
#include "lfs_util.h"
#include <string.h>
#include <stdlib.h>
/// Block device operations ///
static int lfs_bd_flush(lfs_t *lfs) {
if (lfs->pcache.off != -1) {
int err = lfs->cfg->prog(lfs->cfg, lfs->pcache.block,
lfs->pcache.off, lfs->pcache.buffer, lfs->cfg->prog_size);
if (err) {
return err;
}
lfs->pcache.off = -1;
}
return 0;
}
static int lfs_bd_read(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
// flush overlapping programs
while (size > 0) {
if (block == lfs->pcache.block && off >= lfs->pcache.off &&
off < lfs->pcache.off + lfs->cfg->prog_size) {
// is already in cache?
lfs_size_t diff = lfs_min(size,
lfs->cfg->prog_size - (off-lfs->pcache.off));
memcpy(data, &lfs->pcache.buffer[off-lfs->pcache.off], diff);
data += diff;
off += diff;
size -= diff;
continue;
} else if (block == lfs->rcache.block && off >= lfs->rcache.off &&
off < lfs->rcache.off + lfs->cfg->read_size) {
// is already in cache?
lfs_size_t diff = lfs_min(size,
lfs->cfg->read_size - (off-lfs->rcache.off));
memcpy(data, &lfs->rcache.buffer[off-lfs->rcache.off], diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// write out pending programs
int err = lfs_bd_flush(lfs);
if (err) {
return err;
}
if (off % lfs->cfg->read_size == 0 &&
size >= lfs->cfg->read_size) {
// bypass cache?
lfs_size_t diff = size - (size % lfs->cfg->read_size);
int err = lfs->cfg->read(lfs->cfg, block, off, data, diff);
if (err) {
return err;
}
data += diff;
off += diff;
size -= diff;
continue;
}
// load to cache, first condition can no longer fail
lfs->rcache.block = block;
lfs->rcache.off = off - (off % lfs->cfg->read_size);
err = lfs->cfg->read(lfs->cfg, lfs->rcache.block,
lfs->rcache.off, lfs->rcache.buffer, lfs->cfg->read_size);
if (err) {
return err;
}
}
return 0;
}
static int lfs_bd_prog(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
if (block == lfs->rcache.block) {
// invalidate read cache
lfs->rcache.off = -1;
}
while (size > 0) {
if (block == lfs->pcache.block && off >= lfs->pcache.off &&
off < lfs->pcache.off + lfs->cfg->prog_size) {
// is already in cache?
lfs_size_t diff = lfs_min(size,
lfs->cfg->prog_size - (off-lfs->pcache.off));
memcpy(&lfs->pcache.buffer[off-lfs->pcache.off], data, diff);
data += diff;
off += diff;
size -= diff;
continue;
}
// write out pending programs
int err = lfs_bd_flush(lfs);
if (err) {
return err;
}
if (off % lfs->cfg->prog_size == 0 &&
size >= lfs->cfg->prog_size) {
// bypass cache?
lfs_size_t diff = size - (size % lfs->cfg->prog_size);
int err = lfs->cfg->prog(lfs->cfg, block, off, data, diff);
if (err) {
return err;
}
data += diff;
off += diff;
size -= diff;
continue;
}
// prepare cache, first condition can no longer fail
lfs->pcache.block = block;
lfs->pcache.off = off - (off % lfs->cfg->prog_size);
}
return 0;
}
static int lfs_bd_erase(lfs_t *lfs, lfs_block_t block) {
return lfs->cfg->erase(lfs->cfg, block);
}
static int lfs_bd_sync(lfs_t *lfs) {
int err = lfs_bd_flush(lfs);
if (err) {
return err;
}
return lfs->cfg->sync(lfs->cfg);
}
static int lfs_bd_cmp(lfs_t *lfs, lfs_block_t block,
lfs_off_t off, lfs_size_t size, const void *buffer) {
const uint8_t *data = buffer;
for (lfs_off_t i = 0; i < size; i++) {
uint8_t c;
int err = lfs_bd_read(lfs, block, off+i, &c, 1);
if (err) {
return err;
}
if (c != data[i]) {
return false;
}
}
return true;
}
/// Block allocator ///
static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
lfs_t *lfs = p;
lfs_block_t off = (block - lfs->free.start) % lfs->cfg->block_count;
if (off < lfs->cfg->lookahead) {
lfs->free.lookahead[off / 32] |= 1U << (off % 32);
}
return 0;
}
static int lfs_alloc_scan(lfs_t *lfs, lfs_block_t *block) {
lfs_block_t end = lfs->free.start + lfs->cfg->block_count;
while (true) {
while (lfs->free.off < lfs->cfg->lookahead) {
lfs_block_t off = lfs->free.off;
lfs->free.off += 1;
if (!(lfs->free.lookahead[off / 32] & (1U << (off % 32)))) {
// found a free block
*block = (lfs->free.start + off) % lfs->cfg->block_count;
return 0;
}
}
// could not find block
lfs->free.start += lfs->cfg->lookahead;
lfs->free.off = 0;
if (lfs_scmp(lfs->free.start, end) > 0) {
return LFS_ERR_NOSPC;
}
// find mask of free blocks from tree
memset(lfs->free.lookahead, 0, lfs->cfg->lookahead/8);
int err = lfs_traverse(lfs, lfs_alloc_lookahead, lfs);
if (err) {
return err;
}
}
}
static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
// try to scan for free block
int err = lfs_alloc_scan(lfs, block);
if (err != LFS_ERR_NOSPC) {
return err;
}
// still can't allocate a block? check for orphans
err = lfs_deorphan(lfs);
if (err) {
return err;
}
// scan again or die trying
err = lfs_alloc_scan(lfs, block);
if (err) {
LFS_WARN("No more free space%s", "");
return err;
}
return 0;
}
/// Metadata pair and directory operations ///
static inline void lfs_pairswap(lfs_block_t pair[2]) {
lfs_block_t t = pair[0];
pair[0] = pair[1];
pair[1] = t;
}
static inline bool lfs_pairisnull(const lfs_block_t pair[2]) {
return !pair[0] || !pair[1];
}
static inline int lfs_paircmp(
const lfs_block_t paira[2],
const lfs_block_t pairb[2]) {
return !(paira[0] == pairb[0] || paira[1] == pairb[1] ||
paira[0] == pairb[1] || paira[1] == pairb[0]);
}
static int lfs_dir_alloc(lfs_t *lfs, lfs_dir_t *dir) {
// allocate pair of dir blocks
for (int i = 0; i < 2; i++) {
int err = lfs_alloc(lfs, &dir->pair[i]);
if (err) {
return err;
}
}
// we couldn't find unique blocks, we're out of space
if (dir->pair[0] == dir->pair[1]) {
return LFS_ERR_NOSPC;
}
// rather than clobbering one of the blocks we just pretend
// the revision may be valid
int err = lfs_bd_read(lfs, dir->pair[0], 0, &dir->d.rev, 4);
if (err) {
return err;
}
// set defaults
dir->d.rev += 1;
dir->d.size = sizeof(dir->d);
dir->d.tail[0] = 0;
dir->d.tail[1] = 0;
dir->off = sizeof(dir->d);
// don't write out yet, let caller take care of that
return 0;
}
static int lfs_dir_fetch(lfs_t *lfs,
lfs_dir_t *dir, const lfs_block_t pair[2]) {
// copy out pair, otherwise may be aliasing dir
const lfs_block_t tpair[2] = {pair[0], pair[1]};
bool valid = false;
// check both blocks for the most recent revision
for (int i = 0; i < 2; i++) {
struct lfs_disk_dir test;
int err = lfs_bd_read(lfs, tpair[i], 0, &test, sizeof(test));
if (err) {
return err;
}
if (valid && lfs_scmp(test.rev, dir->d.rev) < 0) {
continue;
}
uint32_t crc = 0xffffffff;
crc = lfs_crc(crc, &test, sizeof(test));
for (lfs_off_t j = sizeof(test); j < lfs->cfg->block_size; j += 4) {
uint32_t word;
int err = lfs_bd_read(lfs, tpair[i], j, &word, 4);
if (err) {
return err;
}
crc = lfs_crc(crc, &word, 4);
}
if (crc != 0) {
continue;
}
valid = true;
// setup dir in case it's valid
dir->pair[0] = tpair[(i+0) % 2];
dir->pair[1] = tpair[(i+1) % 2];
dir->off = sizeof(dir->d);
dir->d = test;
}
if (!valid) {
LFS_ERROR("Corrupted dir pair at %d %d", tpair[0], tpair[1]);
return LFS_ERR_CORRUPT;
}
return 0;
}
static int lfs_dir_commit(lfs_t *lfs, lfs_dir_t *dir,
const lfs_entry_t *entry, const void *data) {
dir->d.rev += 1;
lfs_pairswap(dir->pair);
int err = lfs_bd_erase(lfs, dir->pair[0]);
if (err) {
return err;
}
uint32_t crc = 0xffffffff;
crc = lfs_crc(crc, &dir->d, sizeof(dir->d));
err = lfs_bd_prog(lfs, dir->pair[0], 0, &dir->d, sizeof(dir->d));
if (err) {
return err;
}
lfs_off_t off = sizeof(dir->d);
lfs_size_t size = 0x7fffffff & dir->d.size;
while (off < size) {
if (entry && off == entry->off) {
crc = lfs_crc(crc, &entry->d, sizeof(entry->d));
int err = lfs_bd_prog(lfs, dir->pair[0],
off, &entry->d, sizeof(entry->d));
if (err) {
return err;
}
off += sizeof(entry->d);
if (data) {
crc = lfs_crc(crc, data, entry->d.len - sizeof(entry->d));
int err = lfs_bd_prog(lfs, dir->pair[0],
off, data, entry->d.len - sizeof(entry->d));
if (err) {
return err;
}
off += entry->d.len - sizeof(entry->d);
}
} else {
uint8_t data;
int err = lfs_bd_read(lfs, dir->pair[1], off, &data, 1);
if (err) {
return err;
}
crc = lfs_crc(crc, &data, 1);
err = lfs_bd_prog(lfs, dir->pair[0], off, &data, 1);
if (err) {
return err;
}
off += 1;
}
}
while (off < lfs->cfg->block_size-4) {
uint8_t data = 0xff;
crc = lfs_crc(crc, &data, 1);
err = lfs_bd_prog(lfs, dir->pair[0], off, &data, 1);
if (err) {
return err;
}
off += 1;
}
err = lfs_bd_prog(lfs, dir->pair[0], lfs->cfg->block_size-4, &crc, 4);
if (err) {
return err;
}
return lfs_bd_sync(lfs);
}
static int lfs_dir_shift(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry) {
dir->d.rev += 1;
dir->d.size -= entry->d.len;
lfs_pairswap(dir->pair);
int err = lfs_bd_erase(lfs, dir->pair[0]);
if (err) {
return err;
}
uint32_t crc = 0xffffffff;
crc = lfs_crc(crc, &dir->d, sizeof(dir->d));
err = lfs_bd_prog(lfs, dir->pair[0], 0, &dir->d, sizeof(dir->d));
if (err) {
return err;
}
lfs_off_t woff = sizeof(dir->d);
lfs_off_t roff = sizeof(dir->d);
lfs_size_t size = 0x7fffffff & dir->d.size;
while (woff < size) {
if (roff == entry->off) {
roff += entry->d.len;
} else {
uint8_t data;
int err = lfs_bd_read(lfs, dir->pair[1], roff, &data, 1);
if (err) {
return err;
}
crc = lfs_crc(crc, &data, 1);
err = lfs_bd_prog(lfs, dir->pair[0], woff, &data, 1);
if (err) {
return err;
}
woff += 1;
roff += 1;
}
}
while (woff < lfs->cfg->block_size-4) {
uint8_t data = 0xff;
crc = lfs_crc(crc, &data, 1);
err = lfs_bd_prog(lfs, dir->pair[0], woff, &data, 1);
if (err) {
return err;
}
woff += 1;
}
err = lfs_bd_prog(lfs, dir->pair[0], lfs->cfg->block_size-4, &crc, 4);
if (err) {
return err;
}
return lfs_bd_sync(lfs);
}
static int lfs_dir_append(lfs_t *lfs, lfs_dir_t *dir,
lfs_entry_t *entry, const void *data) {
// check if we fit, if top bit is set we do not and move on
while (true) {
if (dir->d.size + entry->d.len <= lfs->cfg->block_size - 4) {
entry->off = dir->d.size;
dir->d.size += entry->d.len;
return lfs_dir_commit(lfs, dir, entry, data);
}
// we need to allocate a new dir block
if (!(0x80000000 & dir->d.size)) {
lfs_dir_t newdir;
int err = lfs_dir_alloc(lfs, &newdir);
if (err) {
return err;
}
// our allocator doesn't track blocks before being appended,
// so even if we found some blocks, they may not be unique
if (entry->d.type == LFS_TYPE_DIR &&
lfs_paircmp(entry->d.u.dir, newdir.pair) == 0) {
return LFS_ERR_NOSPC;
}
newdir.d.tail[0] = dir->d.tail[0];
newdir.d.tail[1] = dir->d.tail[1];
entry->off = newdir.d.size;
newdir.d.size += entry->d.len;
err = lfs_dir_commit(lfs, &newdir, entry, data);
if (err) {
return err;
}
dir->d.size |= 0x80000000;
dir->d.tail[0] = newdir.pair[0];
dir->d.tail[1] = newdir.pair[1];
return lfs_dir_commit(lfs, dir, NULL, NULL);
}
int err = lfs_dir_fetch(lfs, dir, dir->d.tail);
if (err) {
return err;
}
}
}
static int lfs_dir_remove(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry) {
// either shift out the one entry or remove the whole dir block
if (dir->d.size == sizeof(dir->d)) {
lfs_dir_t pdir;
int err = lfs_dir_fetch(lfs, &pdir, lfs->root);
if (err) {
return err;
}
while (lfs_paircmp(pdir.d.tail, dir->pair) != 0) {
int err = lfs_dir_fetch(lfs, &pdir, pdir.d.tail);
if (err) {
return err;
}
}
if (!(pdir.d.size & 0x80000000)) {
return lfs_dir_shift(lfs, dir, entry);
} else {
pdir.d.tail[0] = dir->d.tail[0];
pdir.d.tail[1] = dir->d.tail[1];
return lfs_dir_commit(lfs, &pdir, NULL, NULL);
}
} else {
return lfs_dir_shift(lfs, dir, entry);
}
}
static int lfs_dir_next(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry) {
while (true) {
if (dir->off + sizeof(entry->d) > (0x7fffffff & dir->d.size)) {
if (!(0x80000000 & dir->d.size)) {
entry->off = dir->off;
return LFS_ERR_NOENT;
}
int err = lfs_dir_fetch(lfs, dir, dir->d.tail);
if (err) {
return err;
}
dir->off = sizeof(dir->d);
dir->pos += sizeof(dir->d);
continue;
}
int err = lfs_bd_read(lfs, dir->pair[0], dir->off,
&entry->d, sizeof(entry->d));
if (err) {
return err;
}
dir->off += entry->d.len;
dir->pos += entry->d.len;
if ((0xff & entry->d.type) == LFS_TYPE_REG ||
(0xff & entry->d.type) == LFS_TYPE_DIR) {
entry->off = dir->off - entry->d.len;
return 0;
}
}
}
static int lfs_dir_find(lfs_t *lfs, lfs_dir_t *dir,
lfs_entry_t *entry, const char **path) {
const char *pathname = *path;
size_t pathlen;
while (true) {
nextname:
// skip slashes
pathname += strspn(pathname, "/");
pathlen = strcspn(pathname, "/");
// skip '.' and root '..'
if ((pathlen == 1 && memcmp(pathname, ".", 1) == 0) ||
(pathlen == 2 && memcmp(pathname, "..", 2) == 0)) {
pathname += pathlen;
goto nextname;
}
// skip if matched by '..' in name
const char *suffix = pathname + pathlen;
size_t sufflen;
int depth = 1;
while (true) {
suffix += strspn(suffix, "/");
sufflen = strcspn(suffix, "/");
if (sufflen == 0) {
break;
}
if (sufflen == 2 && memcmp(suffix, "..", 2) == 0) {
depth -= 1;
if (depth == 0) {
pathname = suffix + sufflen;
goto nextname;
}
} else {
depth += 1;
}
suffix += sufflen;
}
// find path
while (true) {
int err = lfs_dir_next(lfs, dir, entry);
if (err) {
return err;
}
if (entry->d.len - sizeof(entry->d) != pathlen) {
continue;
}
int ret = lfs_bd_cmp(lfs, dir->pair[0],
entry->off + sizeof(entry->d), pathlen, pathname);
if (ret < 0) {
return ret;
}
// Found match
if (ret == true) {
break;
}
}
pathname += pathlen;
pathname += strspn(pathname, "/");
if (pathname[0] == '\0') {
return 0;
}
// continue on if we hit a directory
if (entry->d.type != LFS_TYPE_DIR) {
return LFS_ERR_NOTDIR;
}
int err = lfs_dir_fetch(lfs, dir, entry->d.u.dir);
if (err) {
return err;
}
*path = pathname;
}
return 0;
}
/// Top level directory operations ///
int lfs_mkdir(lfs_t *lfs, const char *path) {
// fetch parent directory
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err != LFS_ERR_NOENT) {
return err ? err : LFS_ERR_EXISTS;
}
// Build up new directory
lfs_dir_t dir;
err = lfs_dir_alloc(lfs, &dir);
if (err) {
return err;
}
dir.d.tail[0] = cwd.d.tail[0];
dir.d.tail[1] = cwd.d.tail[1];
err = lfs_dir_commit(lfs, &dir, NULL, NULL);
if (err) {
return err;
}
entry.d.type = LFS_TYPE_DIR;
entry.d.len = sizeof(entry.d) + strlen(path);
entry.d.u.dir[0] = dir.pair[0];
entry.d.u.dir[1] = dir.pair[1];
cwd.d.tail[0] = dir.pair[0];
cwd.d.tail[1] = dir.pair[1];
return lfs_dir_append(lfs, &cwd, &entry, path);
}
int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path) {
dir->pair[0] = lfs->root[0];
dir->pair[1] = lfs->root[1];
int err = lfs_dir_fetch(lfs, dir, dir->pair);
if (err) {
return err;
}
if (strspn(path, "/.") == strlen(path)) {
// can only be something like '/././../.'
dir->head[0] = dir->pair[0];
dir->head[1] = dir->pair[1];
dir->pos = sizeof(dir->d) - 2;
dir->off = sizeof(dir->d);
return 0;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, dir, &entry, &path);
if (err) {
return err;
} else if (entry.d.type != LFS_TYPE_DIR) {
return LFS_ERR_NOTDIR;
}
err = lfs_dir_fetch(lfs, dir, entry.d.u.dir);
if (err) {
return err;
}
// setup head dir
// special offset for '.' and '..'
dir->head[0] = dir->pair[0];
dir->head[1] = dir->pair[1];
dir->pos = sizeof(dir->d) - 2;
dir->off = sizeof(dir->d);
return 0;
}
int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir) {
// Do nothing, dir is always synchronized
return 0;
}
int lfs_dir_read(lfs_t *lfs, lfs_dir_t *dir, struct lfs_info *info) {
memset(info, 0, sizeof(*info));
// special offset for '.' and '..'
if (dir->pos == sizeof(dir->d) - 2) {
info->type = LFS_TYPE_DIR;
strcpy(info->name, ".");
dir->pos += 1;
return 1;
} else if (dir->pos == sizeof(dir->d) - 1) {
info->type = LFS_TYPE_DIR;
strcpy(info->name, "..");
dir->pos += 1;
return 1;
}
lfs_entry_t entry;
int err = lfs_dir_next(lfs, dir, &entry);
if (err) {
return (err == LFS_ERR_NOENT) ? 0 : err;
}
info->type = entry.d.type & 0xff;
if (info->type == LFS_TYPE_REG) {
info->size = entry.d.u.file.size;
}
err = lfs_bd_read(lfs, dir->pair[0], entry.off + sizeof(entry.d),
info->name, entry.d.len - sizeof(entry.d));
if (err) {
return err;
}
return 1;
}
int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off) {
// simply walk from head dir
int err = lfs_dir_rewind(lfs, dir);
if (err) {
return err;
}
dir->pos = off;
while (off > (0x7fffffff & dir->d.size)) {
off -= 0x7fffffff & dir->d.size;
if (!(0x80000000 & dir->d.size)) {
return LFS_ERR_INVAL;
}
int err = lfs_dir_fetch(lfs, dir, dir->d.tail);
if (err) {
return err;
}
}
dir->off = off;
return 0;
}
lfs_soff_t lfs_dir_tell(lfs_t *lfs, lfs_dir_t *dir) {
return dir->pos;
}
int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir) {
// reload the head dir
int err = lfs_dir_fetch(lfs, dir, dir->head);
if (err) {
return err;
}
dir->pair[0] = dir->head[0];
dir->pair[1] = dir->head[1];
dir->pos = sizeof(dir->d) - 2;
dir->off = sizeof(dir->d);
return 0;
}
/// Index list operations ///
static int lfs_index(lfs_t *lfs, lfs_off_t *off) {
lfs_off_t i = 0;
while (*off >= lfs->cfg->block_size) {
i += 1;
*off -= lfs->cfg->block_size;
*off += 4*lfs_min(lfs_ctz(i)+1, lfs->words-1);
}
return i;
}
static int lfs_index_find(lfs_t *lfs, lfs_block_t head, lfs_size_t size,
lfs_size_t pos, lfs_block_t *block, lfs_off_t *off) {
if (size == 0) {
*block = 0;
*off = 0;
return 0;
}
lfs_off_t current = lfs_index(lfs, &(lfs_off_t){size-1});
lfs_off_t target = lfs_index(lfs, &pos);
while (current > target) {
lfs_size_t skip = lfs_min(
lfs_npw2(current-target+1) - 1,
lfs_min(lfs_ctz(current)+1, lfs->words-1) - 1);
int err = lfs_bd_read(lfs, head, 4*skip, &head, 4);
if (err) {
return err;
}
current -= 1 << skip;
}
*block = head;
*off = pos;
return 0;
}
static int lfs_index_extend(lfs_t *lfs,
lfs_block_t head, lfs_size_t size,
lfs_off_t *block, lfs_block_t *off) {
// go ahead and grab a block
int err = lfs_alloc(lfs, block);
if (err) {
return err;
}
err = lfs_bd_erase(lfs, *block);
if (err) {
return err;
}
if (size == 0) {
*off = 0;
return 0;
}
size -= 1;
lfs_off_t index = lfs_index(lfs, &size);
size += 1;
// just copy out the last block if it is incomplete
if (size != lfs->cfg->block_size) {
for (lfs_off_t i = 0; i < size; i++) {
uint8_t data;
int err = lfs_bd_read(lfs, head, i, &data, 1);
if (err) {
return err;
}
err = lfs_bd_prog(lfs, *block, i, &data, 1);
if (err) {
return err;
}
}
*off = size;
return 0;
}
// append block
index += 1;
lfs_size_t skips = lfs_min(lfs_ctz(index)+1, lfs->words-1);
for (lfs_off_t i = 0; i < skips; i++) {
int err = lfs_bd_prog(lfs, *block, 4*i, &head, 4);
if (err) {
return err;
}
if (i != skips-1) {
err = lfs_bd_read(lfs, head, 4*i, &head, 4);
if (err) {
return err;
}
}
}
*off = 4*skips;
return 0;
}
static int lfs_index_traverse(lfs_t *lfs,
lfs_block_t head, lfs_size_t size,
int (*cb)(void*, lfs_block_t), void *data) {
if (size == 0) {
return 0;
}
lfs_off_t index = lfs_index(lfs, &(lfs_off_t){size-1});
while (true) {
int err = cb(data, head);
if (err) {
return err;
}
if (index == 0) {
return 0;
}
err = lfs_bd_read(lfs, head, 0, &head, 4);
if (err) {
return err;
}
index -= 1;
}
return 0;
}
/// Top level file operations ///
int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
const char *path, int flags) {
// Allocate entry for file if it doesn't exist
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
if (!(flags & LFS_O_CREAT)) {
return LFS_ERR_NOENT;
}
// create entry to remember name
entry.d.type = LFS_TYPE_REG;
entry.d.len = sizeof(entry.d) + strlen(path);
entry.d.u.file.head = 0;
entry.d.u.file.size = 0;
err = lfs_dir_append(lfs, &cwd, &entry, path);
if (err) {
return err;
}
} else if (entry.d.type == LFS_TYPE_DIR) {
return LFS_ERR_ISDIR;
} else if (flags & LFS_O_EXCL) {
return LFS_ERR_EXISTS;
}
// setup file struct
file->pair[0] = cwd.pair[0];
file->pair[1] = cwd.pair[1];
file->off = entry.off;
file->head = entry.d.u.file.head;
file->size = entry.d.u.file.size;
file->flags = flags;
file->pos = 0;
file->wblock = 0;
file->rblock = 0;
if (flags & LFS_O_TRUNC) {
file->head = 0;
file->size = 0;
}
// add to list of files
file->next = lfs->files;
lfs->files = file;
return 0;
}
int lfs_file_close(lfs_t *lfs, lfs_file_t *file) {
int err = lfs_file_sync(lfs, file);
// remove from list of files
for (lfs_file_t **p = &lfs->files; *p; p = &(*p)->next) {
if (*p == file) {
*p = file->next;
break;
}
}
return err;
}
static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file) {
if (file->rblock) {
// just drop read block
file->rblock = 0;
}
if (file->wblock) {
lfs_off_t pos = file->pos;
// copy over anything after current branch
lfs_file_t orig = {
.head = file->head,
.size = file->size,
.flags = LFS_O_RDONLY,
.pos = file->pos,
.rblock = 0,
};
while (file->pos < file->size) {
uint8_t data;
lfs_ssize_t res = lfs_file_read(lfs, &orig, &data, 1);
if (res < 0) {
return res;
}
res = lfs_file_write(lfs, file, &data, 1);
if (res < 0) {
return res;
}
}
// actual file updates
file->head = file->wblock;
file->size = file->pos;
file->wblock = 0;
file->flags |= LFS_O_DIRTY;
file->pos = pos;
}
return 0;
}
int lfs_file_sync(lfs_t *lfs, lfs_file_t *file) {
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
if (file->flags & LFS_O_DIRTY) {
// update dir entry
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, file->pair);
if (err) {
return err;
}
lfs_entry_t entry = {.off = file->off};
err = lfs_bd_read(lfs, cwd.pair[0], entry.off,
&entry.d, sizeof(entry.d));
if (err) {
return err;
}
if (entry.d.type != LFS_TYPE_REG) {
// sanity check valid entry
return LFS_ERR_INVAL;
}
entry.d.u.file.head = file->head;
entry.d.u.file.size = file->size;
err = lfs_dir_commit(lfs, &cwd, &entry, NULL);
if (err) {
return err;
}
file->flags &= ~LFS_O_DIRTY;
}
return 0;
}
lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
void *buffer, lfs_size_t size) {
uint8_t *data = buffer;
lfs_size_t nsize = size;
if ((file->flags & 3) == LFS_O_WRONLY) {
return LFS_ERR_INVAL;
}
if (file->wblock) {
// flush out any writes
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
}
size = lfs_min(size, file->size - file->pos);
nsize = size;
while (nsize > 0) {
// check if we need a new block
if (!file->rblock || file->roff == lfs->cfg->block_size) {
int err = lfs_index_find(lfs, file->head, file->size,
file->pos, &file->rblock, &file->roff);
if (err) {
return err;
}
}
// read as much as we can in current block
lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->roff);
int err = lfs_bd_read(lfs, file->rblock, file->roff, data, diff);
if (err) {
return err;
}
file->pos += diff;
file->roff += diff;
data += diff;
nsize -= diff;
}
return size;
}
lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
const void *buffer, lfs_size_t size) {
const uint8_t *data = buffer;
lfs_size_t nsize = size;
if ((file->flags & 3) == LFS_O_RDONLY) {
return LFS_ERR_INVAL;
}
if (file->rblock) {
// drop any reads
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
}
if ((file->flags & LFS_O_APPEND) && file->pos < file->size) {
file->pos = file->size;
}
while (nsize > 0) {
// check if we need a new block
if (!file->wblock || file->woff == lfs->cfg->block_size) {
if (!file->wblock) {
// find out which block we're extending from
int err = lfs_index_find(lfs, file->head, file->size,
file->pos, &file->wblock, &file->woff);
if (err) {
return err;
}
}
// extend file with new blocks
int err = lfs_index_extend(lfs, file->wblock, file->pos,
&file->wblock, &file->woff);
if (err) {
return err;
}
}
// program as much as we can in current block
lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->woff);
int err = lfs_bd_prog(lfs, file->wblock, file->woff, data, diff);
if (err) {
return err;
}
file->pos += diff;
file->woff += diff;
data += diff;
nsize -= diff;
}
if (file->flags & LFS_O_SYNC) {
int err = lfs_file_sync(lfs, file);
if (err) {
return err;
}
}
return size;
}
lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
lfs_soff_t off, int whence) {
// write out everything beforehand, may be noop if rdonly
int err = lfs_file_flush(lfs, file);
if (err) {
return err;
}
// update pos
lfs_off_t pos = file->pos;
if (whence == LFS_SEEK_SET) {
file->pos = off;
} else if (whence == LFS_SEEK_CUR) {
file->pos = file->pos + off;
} else if (whence == LFS_SEEK_END) {
file->pos = file->size + off;
}
return pos;
}
lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file) {
return file->pos;
}
int lfs_file_rewind(lfs_t *lfs, lfs_file_t *file) {
lfs_soff_t res = lfs_file_seek(lfs, file, 0, LFS_SEEK_SET);
if (res < 0) {
return res;
}
return 0;
}
lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file) {
return lfs_max(file->pos, file->size);
}
/// General fs oprations ///
int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err) {
return err;
}
memset(info, 0, sizeof(*info));
info->type = entry.d.type & 0xff;
if (info->type == LFS_TYPE_REG) {
info->size = entry.d.u.file.size;
}
err = lfs_bd_read(lfs, cwd.pair[0], entry.off + sizeof(entry.d),
info->name, entry.d.len - sizeof(entry.d));
if (err) {
return err;
}
return 0;
}
int lfs_remove(lfs_t *lfs, const char *path) {
lfs_dir_t cwd;
int err = lfs_dir_fetch(lfs, &cwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t entry;
err = lfs_dir_find(lfs, &cwd, &entry, &path);
if (err) {
return err;
}
lfs_dir_t dir;
if (entry.d.type == LFS_TYPE_DIR) {
// must be empty before removal, checking size
// without masking top bit checks for any case where
// dir is not empty
int err = lfs_dir_fetch(lfs, &dir, entry.d.u.dir);
if (err) {
return err;
} else if (dir.d.size != sizeof(dir.d)) {
return LFS_ERR_INVAL;
}
}
// remove the entry
err = lfs_dir_remove(lfs, &cwd, &entry);
if (err) {
return err;
}
// if we were a directory, just run a deorphan step, this should
// collect us, although is expensive
if (entry.d.type == LFS_TYPE_DIR) {
int err = lfs_deorphan(lfs);
if (err) {
return err;
}
}
return 0;
}
int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
// find old entry
lfs_dir_t oldcwd;
int err = lfs_dir_fetch(lfs, &oldcwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t oldentry;
err = lfs_dir_find(lfs, &oldcwd, &oldentry, &oldpath);
if (err) {
return err;
}
// allocate new entry
lfs_dir_t newcwd;
err = lfs_dir_fetch(lfs, &newcwd, lfs->root);
if (err) {
return err;
}
lfs_entry_t preventry;
err = lfs_dir_find(lfs, &newcwd, &preventry, &newpath);
if (err && err != LFS_ERR_NOENT) {
return err;
}
bool prevexists = (err != LFS_ERR_NOENT);
// must have same type
if (prevexists && preventry.d.type != oldentry.d.type) {
return LFS_ERR_INVAL;
}
lfs_dir_t dir;
if (prevexists && preventry.d.type == LFS_TYPE_DIR) {
// must be empty before removal, checking size
// without masking top bit checks for any case where
// dir is not empty
int err = lfs_dir_fetch(lfs, &dir, preventry.d.u.dir);
if (err) {
return err;
} else if (dir.d.size != sizeof(dir.d)) {
return LFS_ERR_INVAL;
}
}
// move to new location
lfs_entry_t newentry = preventry;
newentry.d = oldentry.d;
newentry.d.len = sizeof(newentry.d) + strlen(newpath);
if (prevexists) {
int err = lfs_dir_commit(lfs, &newcwd, &newentry, newpath);
if (err) {
return err;
}
} else {
int err = lfs_dir_append(lfs, &newcwd, &newentry, newpath);
if (err) {
return err;
}
}
// fetch again in case newcwd == oldcwd
err = lfs_dir_fetch(lfs, &oldcwd, oldcwd.pair);
if (err) {
return err;
}
err = lfs_dir_find(lfs, &oldcwd, &oldentry, &oldpath);
if (err) {
return err;
}
// remove from old location
err = lfs_dir_remove(lfs, &oldcwd, &oldentry);
if (err) {
return err;
}
// if we were a directory, just run a deorphan step, this should
// collect us, although is expensive
if (prevexists && preventry.d.type == LFS_TYPE_DIR) {
int err = lfs_deorphan(lfs);
if (err) {
return err;
}
}
return 0;
}
/// Filesystem operations ///
static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
lfs->cfg = cfg;
lfs->words = lfs->cfg->block_size / sizeof(uint32_t);
// setup read cache
lfs->rcache.off = -1;
if (lfs->cfg->read_buffer) {
lfs->rcache.buffer = lfs->cfg->read_buffer;
} else {
lfs->rcache.buffer = malloc(lfs->cfg->read_size);
if (!lfs->rcache.buffer) {
return LFS_ERR_NOMEM;
}
}
// setup program cache
lfs->pcache.off = -1;
if (lfs->cfg->prog_buffer) {
lfs->pcache.buffer = lfs->cfg->prog_buffer;
} else {
lfs->pcache.buffer = malloc(lfs->cfg->prog_size);
if (!lfs->pcache.buffer) {
return LFS_ERR_NOMEM;
}
}
// setup lookahead
if (lfs->cfg->lookahead_buffer) {
lfs->free.lookahead = lfs->cfg->lookahead_buffer;
} else {
lfs->free.lookahead = malloc(lfs->cfg->lookahead/8);
if (!lfs->free.lookahead) {
return LFS_ERR_NOMEM;
}
}
// setup files as an empty list
lfs->files = NULL;
return 0;
}
static int lfs_deinit(lfs_t *lfs) {
// Free allocated memory
if (!lfs->cfg->read_buffer) {
free(lfs->rcache.buffer);
}
if (!lfs->cfg->prog_buffer) {
free(lfs->pcache.buffer);
}
if (!lfs->cfg->lookahead_buffer) {
free(lfs->free.lookahead);
}
return 0;
}
int lfs_format(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// Create free lookahead
memset(lfs->free.lookahead, 0, lfs->cfg->lookahead/8);
lfs->free.start = 0;
lfs->free.off = 0;
// Create superblock dir
lfs_dir_t superdir;
err = lfs_dir_alloc(lfs, &superdir);
if (err) {
return err;
}
// Write root directory
lfs_dir_t root;
err = lfs_dir_alloc(lfs, &root);
if (err) {
return err;
}
err = lfs_dir_commit(lfs, &root, NULL, NULL);
if (err) {
return err;
}
lfs->root[0] = root.pair[0];
lfs->root[1] = root.pair[1];
// Write superblocks
lfs_superblock_t superblock = {
.off = sizeof(superdir.d),
.d.type = LFS_TYPE_SUPERBLOCK,
.d.len = sizeof(superblock.d),
.d.version = 0x00000001,
.d.magic = {"littlefs"},
.d.block_size = lfs->cfg->block_size,
.d.block_count = lfs->cfg->block_count,
.d.root = {lfs->root[0], lfs->root[1]},
};
superdir.d.tail[0] = root.pair[0];
superdir.d.tail[1] = root.pair[1];
superdir.d.size += sizeof(superdir.d);
for (int i = 0; i < 2; i++) {
// Write both pairs for extra safety, do some finagling to pretend
// the superblock is an entry
int err = lfs_dir_commit(lfs, &superdir,
(const lfs_entry_t*)&superblock,
(const struct lfs_disk_entry*)&superblock.d + 1);
if (err) {
LFS_ERROR("Failed to write superblock at %d", superdir.pair[0]);
return err;
}
}
// sanity check that fetch works
err = lfs_dir_fetch(lfs, &superdir, (const lfs_block_t[2]){0, 1});
if (err) {
return err;
}
return lfs_deinit(lfs);
}
int lfs_mount(lfs_t *lfs, const struct lfs_config *cfg) {
int err = lfs_init(lfs, cfg);
if (err) {
return err;
}
// setup free lookahead
lfs->free.start = -lfs->cfg->lookahead;
lfs->free.off = lfs->cfg->lookahead;
// load superblock
lfs_dir_t dir;
lfs_superblock_t superblock;
err = lfs_dir_fetch(lfs, &dir, (const lfs_block_t[2]){0, 1});
if (!err) {
err = lfs_bd_read(lfs, dir.pair[0],
sizeof(dir.d), &superblock.d, sizeof(superblock.d));
lfs->root[0] = superblock.d.root[0];
lfs->root[1] = superblock.d.root[1];
}
if (err == LFS_ERR_CORRUPT ||
memcmp(superblock.d.magic, "littlefs", 8) != 0) {
LFS_ERROR("Invalid superblock at %d %d", dir.pair[0], dir.pair[1]);
return LFS_ERR_CORRUPT;
}
if (superblock.d.version > 0x0000ffff) {
LFS_ERROR("Invalid version %d.%d\n",
0xffff & (superblock.d.version >> 16),
0xffff & (superblock.d.version >> 0));
return LFS_ERR_INVAL;
}
return err;
}
int lfs_unmount(lfs_t *lfs) {
return lfs_deinit(lfs);
}
/// Littlefs specific operations ///
int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data) {
// iterate over metadata pairs
lfs_dir_t dir;
lfs_entry_t entry;
lfs_block_t cwd[2] = {0, 1};
while (true) {
for (int i = 0; i < 2; i++) {
int err = cb(data, cwd[i]);
if (err) {
return err;
}
}
int err = lfs_dir_fetch(lfs, &dir, cwd);
if (err) {
return err;
}
// iterate over contents
while ((0x7fffffff & dir.d.size) >= dir.off + sizeof(entry.d)) {
int err = lfs_bd_read(lfs, dir.pair[0], dir.off,
&entry.d, sizeof(entry.d));
if (err) {
return err;
}
dir.off += entry.d.len;
if ((0xf & entry.d.type) == LFS_TYPE_REG) {
int err = lfs_index_traverse(lfs,
entry.d.u.file.head, entry.d.u.file.size, cb, data);
if (err) {
return err;
}
}
}
cwd[0] = dir.d.tail[0];
cwd[1] = dir.d.tail[1];
if (lfs_pairisnull(cwd)) {
break;
}
}
// iterate over any open files
for (lfs_file_t *f = lfs->files; f; f = f->next) {
if (f->flags & LFS_O_DIRTY) {
int err = lfs_index_traverse(lfs, f->head, f->size, cb, data);
if (err) {
return err;
}
}
if (f->wblock) {
int err = lfs_index_traverse(lfs, f->wblock, f->pos, cb, data);
if (err) {
return err;
}
}
}
return 0;
}
static int lfs_parent(lfs_t *lfs, const lfs_block_t dir[2]) {
// iterate over all directory directory entries
lfs_dir_t parent = {
.d.tail[0] = lfs->root[0],
.d.tail[1] = lfs->root[1],
};
while (true) {
lfs_entry_t entry;
int err = lfs_dir_fetch(lfs, &parent, parent.d.tail);
if (err) {
return err;
}
while (true) {
int err = lfs_dir_next(lfs, &parent, &entry);
if (err && err != LFS_ERR_NOENT) {
return err;
}
if (err == LFS_ERR_NOENT) {
break;
}
if ((0xf & entry.d.type) == LFS_TYPE_DIR &&
lfs_paircmp(entry.d.u.dir, dir) == 0) {
return true;
}
}
if (lfs_pairisnull(parent.d.tail)) {
return false;
}
}
}
int lfs_deorphan(lfs_t *lfs) {
// iterate over all directories
lfs_dir_t pdir;
lfs_dir_t cdir;
// skip root
int err = lfs_dir_fetch(lfs, &pdir, lfs->root);
if (err) {
return err;
}
while (!lfs_pairisnull(pdir.d.tail)) {
int err = lfs_dir_fetch(lfs, &cdir, pdir.d.tail);
if (err) {
return err;
}
// only check head blocks
if (!(0x80000000 & pdir.d.size)) {
// check if we have a parent
int parent = lfs_parent(lfs, pdir.d.tail);
if (parent < 0) {
return parent;
}
if (!parent) {
// we are an orphan
LFS_DEBUG("Orphan %d %d", pdir.d.tail[0], pdir.d.tail[1]);
pdir.d.tail[0] = cdir.d.tail[0];
pdir.d.tail[1] = cdir.d.tail[1];
err = lfs_dir_commit(lfs, &pdir, NULL, NULL);
if (err) {
return err;
}
break;
}
}
memcpy(&pdir, &cdir, sizeof(pdir));
}
return 0;
}
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