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authorbhgv <bhgv.empire@gmail.com>2020-05-12 12:50:49 +0300
committerbhgv <bhgv.empire@gmail.com>2020-05-12 12:50:49 +0300
commit9b5d5f8a4640dbecdc87e5b6e7e95f71018632cf (patch)
treed3135c3861ef93ed2523642d3c5f64c7819b7def /libiot/lfs
parent73c13e732072c17f3e584e11a51d1f7dc8d88e32 (diff)
parent31b4edc67b75658ce5e2d41f2fc87331f4b26d49 (diff)
Merge branch 'master' of https://github.com/bhgv/Inferno-OS-bhgv
Diffstat (limited to 'libiot/lfs')
-rw-r--r--libiot/lfs/lfs.c2592
-rw-r--r--libiot/lfs/lfs.h495
-rw-r--r--libiot/lfs/lfs_util.c31
-rw-r--r--libiot/lfs/lfs_util.h186
4 files changed, 3304 insertions, 0 deletions
diff --git a/libiot/lfs/lfs.c b/libiot/lfs/lfs.c
new file mode 100644
index 0000000..ebbe7c9
--- /dev/null
+++ b/libiot/lfs/lfs.c
@@ -0,0 +1,2592 @@
+/*
+ * The little filesystem
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include "lfs.h"
+#include "lfs_util.h"
+
+#include <inttypes.h>
+
+
+/// Caching block device operations ///
+static int lfs_cache_read(lfs_t *lfs, lfs_cache_t *rcache,
+ const lfs_cache_t *pcache, lfs_block_t block,
+ lfs_off_t off, void *buffer, lfs_size_t size) {
+ uint8_t *data = buffer;
+ LFS_ASSERT(block < lfs->cfg->block_count);
+
+ while (size > 0) {
+ if (pcache && block == pcache->block && off >= pcache->off &&
+ off < pcache->off + lfs->cfg->prog_size) {
+ // is already in pcache?
+ lfs_size_t diff = lfs_min(size,
+ lfs->cfg->prog_size - (off-pcache->off));
+ memcpy(data, &pcache->buffer[off-pcache->off], diff);
+
+ data += diff;
+ off += diff;
+ size -= diff;
+ continue;
+ }
+
+ if (block == rcache->block && off >= rcache->off &&
+ off < rcache->off + lfs->cfg->read_size) {
+ // is already in rcache?
+ lfs_size_t diff = lfs_min(size,
+ lfs->cfg->read_size - (off-rcache->off));
+ memcpy(data, &rcache->buffer[off-rcache->off], diff);
+
+ data += diff;
+ off += diff;
+ size -= diff;
+ continue;
+ }
+
+ 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
+ rcache->block = block;
+ rcache->off = off - (off % lfs->cfg->read_size);
+ int err = lfs->cfg->read(lfs->cfg, rcache->block,
+ rcache->off, rcache->buffer, lfs->cfg->read_size);
+ if (err) {
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+static int lfs_cache_cmp(lfs_t *lfs, lfs_cache_t *rcache,
+ const lfs_cache_t *pcache, lfs_block_t block,
+ lfs_off_t off, const void *buffer, lfs_size_t size) {
+ const uint8_t *data = buffer;
+
+ for (lfs_off_t i = 0; i < size; i++) {
+ uint8_t c;
+ int err = lfs_cache_read(lfs, rcache, pcache,
+ block, off+i, &c, 1);
+ if (err) {
+ return err;
+ }
+
+ if (c != data[i]) {
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static int lfs_cache_crc(lfs_t *lfs, lfs_cache_t *rcache,
+ const lfs_cache_t *pcache, lfs_block_t block,
+ lfs_off_t off, lfs_size_t size, uint32_t *crc) {
+ for (lfs_off_t i = 0; i < size; i++) {
+ uint8_t c;
+ int err = lfs_cache_read(lfs, rcache, pcache,
+ block, off+i, &c, 1);
+ if (err) {
+ return err;
+ }
+
+ lfs_crc(crc, &c, 1);
+ }
+
+ return 0;
+}
+
+static inline void lfs_cache_drop(lfs_t *lfs, lfs_cache_t *rcache) {
+ // do not zero, cheaper if cache is readonly or only going to be
+ // written with identical data (during relocates)
+ (void)lfs;
+ rcache->block = 0xffffffff;
+}
+
+static inline void lfs_cache_zero(lfs_t *lfs, lfs_cache_t *pcache) {
+ // zero to avoid information leak
+ memset(pcache->buffer, 0xff, lfs->cfg->prog_size);
+ pcache->block = 0xffffffff;
+}
+
+static int lfs_cache_flush(lfs_t *lfs,
+ lfs_cache_t *pcache, lfs_cache_t *rcache) {
+ if (pcache->block != 0xffffffff) {
+ int err = lfs->cfg->prog(lfs->cfg, pcache->block,
+ pcache->off, pcache->buffer, lfs->cfg->prog_size);
+ if (err) {
+ return err;
+ }
+
+ if (rcache) {
+ int res = lfs_cache_cmp(lfs, rcache, NULL, pcache->block,
+ pcache->off, pcache->buffer, lfs->cfg->prog_size);
+ if (res < 0) {
+ return res;
+ }
+
+ if (!res) {
+ return LFS_ERR_CORRUPT;
+ }
+ }
+
+ lfs_cache_zero(lfs, pcache);
+ }
+
+ return 0;
+}
+
+static int lfs_cache_prog(lfs_t *lfs, lfs_cache_t *pcache,
+ lfs_cache_t *rcache, lfs_block_t block,
+ lfs_off_t off, const void *buffer, lfs_size_t size) {
+ const uint8_t *data = buffer;
+ LFS_ASSERT(block < lfs->cfg->block_count);
+
+ while (size > 0) {
+ if (block == pcache->block && off >= pcache->off &&
+ off < pcache->off + lfs->cfg->prog_size) {
+ // is already in pcache?
+ lfs_size_t diff = lfs_min(size,
+ lfs->cfg->prog_size - (off-pcache->off));
+ memcpy(&pcache->buffer[off-pcache->off], data, diff);
+
+ data += diff;
+ off += diff;
+ size -= diff;
+
+ if (off % lfs->cfg->prog_size == 0) {
+ // eagerly flush out pcache if we fill up
+ int err = lfs_cache_flush(lfs, pcache, rcache);
+ if (err) {
+ return err;
+ }
+ }
+
+ continue;
+ }
+
+ // pcache must have been flushed, either by programming and
+ // entire block or manually flushing the pcache
+ LFS_ASSERT(pcache->block == 0xffffffff);
+
+ if (off % lfs->cfg->prog_size == 0 &&
+ size >= lfs->cfg->prog_size) {
+ // bypass pcache?
+ 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;
+ }
+
+ if (rcache) {
+ int res = lfs_cache_cmp(lfs, rcache, NULL,
+ block, off, data, diff);
+ if (res < 0) {
+ return res;
+ }
+
+ if (!res) {
+ return LFS_ERR_CORRUPT;
+ }
+ }
+
+ data += diff;
+ off += diff;
+ size -= diff;
+ continue;
+ }
+
+ // prepare pcache, first condition can no longer fail
+ pcache->block = block;
+ pcache->off = off - (off % lfs->cfg->prog_size);
+ }
+
+ return 0;
+}
+
+
+/// General lfs block device operations ///
+static int lfs_bd_read(lfs_t *lfs, lfs_block_t block,
+ lfs_off_t off, void *buffer, lfs_size_t size) {
+ // if we ever do more than writes to alternating pairs,
+ // this may need to consider pcache
+ return lfs_cache_read(lfs, &lfs->rcache, NULL,
+ block, off, buffer, size);
+}
+
+static int lfs_bd_prog(lfs_t *lfs, lfs_block_t block,
+ lfs_off_t off, const void *buffer, lfs_size_t size) {
+ return lfs_cache_prog(lfs, &lfs->pcache, NULL,
+ block, off, buffer, size);
+}
+
+static int lfs_bd_cmp(lfs_t *lfs, lfs_block_t block,
+ lfs_off_t off, const void *buffer, lfs_size_t size) {
+ return lfs_cache_cmp(lfs, &lfs->rcache, NULL, block, off, buffer, size);
+}
+
+static int lfs_bd_crc(lfs_t *lfs, lfs_block_t block,
+ lfs_off_t off, lfs_size_t size, uint32_t *crc) {
+ return lfs_cache_crc(lfs, &lfs->rcache, NULL, block, off, size, crc);
+}
+
+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) {
+ lfs_cache_drop(lfs, &lfs->rcache);
+
+ int err = lfs_cache_flush(lfs, &lfs->pcache, NULL);
+ if (err) {
+ return err;
+ }
+
+ return lfs->cfg->sync(lfs->cfg);
+}
+
+
+/// Internal operations predeclared here ///
+int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data);
+static int lfs_pred(lfs_t *lfs, const lfs_block_t dir[2], lfs_dir_t *pdir);
+static int lfs_parent(lfs_t *lfs, const lfs_block_t dir[2],
+ lfs_dir_t *parent, lfs_entry_t *entry);
+static int lfs_moved(lfs_t *lfs, const void *e);
+static int lfs_relocate(lfs_t *lfs,
+ const lfs_block_t oldpair[2], const lfs_block_t newpair[2]);
+int lfs_deorphan(lfs_t *lfs);
+
+
+/// Block allocator ///
+static int lfs_alloc_lookahead(void *p, lfs_block_t block) {
+ lfs_t *lfs = p;
+
+ lfs_block_t off = ((block - lfs->free.off)
+ + lfs->cfg->block_count) % lfs->cfg->block_count;
+
+ if (off < lfs->free.size) {
+ lfs->free.buffer[off / 32] |= 1U << (off % 32);
+ }
+
+ return 0;
+}
+
+static int lfs_alloc(lfs_t *lfs, lfs_block_t *block) {
+ while (true) {
+ while (lfs->free.i != lfs->free.size) {
+ lfs_block_t off = lfs->free.i;
+ lfs->free.i += 1;
+ lfs->free.ack -= 1;
+
+ if (!(lfs->free.buffer[off / 32] & (1U << (off % 32)))) {
+ // found a free block
+ *block = (lfs->free.off + off) % lfs->cfg->block_count;
+
+ // eagerly find next off so an alloc ack can
+ // discredit old lookahead blocks
+ while (lfs->free.i != lfs->free.size &&
+ (lfs->free.buffer[lfs->free.i / 32]
+ & (1U << (lfs->free.i % 32)))) {
+ lfs->free.i += 1;
+ lfs->free.ack -= 1;
+ }
+
+ return 0;
+ }
+ }
+
+ // check if we have looked at all blocks since last ack
+ if (lfs->free.ack == 0) {
+ LFS_WARN("No more free space %" PRIu32,
+ lfs->free.i + lfs->free.off);
+ return LFS_ERR_NOSPC;
+ }
+
+ lfs->free.off = (lfs->free.off + lfs->free.size)
+ % lfs->cfg->block_count;
+ lfs->free.size = lfs_min(lfs->cfg->lookahead, lfs->free.ack);
+ lfs->free.i = 0;
+
+ // find mask of free blocks from tree
+ memset(lfs->free.buffer, 0, lfs->cfg->lookahead/8);
+ int err = lfs_traverse(lfs, lfs_alloc_lookahead, lfs);
+ if (err) {
+ return err;
+ }
+ }
+}
+
+static void lfs_alloc_ack(lfs_t *lfs) {
+ lfs->free.ack = lfs->cfg->block_count;
+}
+
+
+/// Endian swapping functions ///
+static void lfs_dir_fromle32(struct lfs_disk_dir *d) {
+ d->rev = lfs_fromle32(d->rev);
+ d->size = lfs_fromle32(d->size);
+ d->tail[0] = lfs_fromle32(d->tail[0]);
+ d->tail[1] = lfs_fromle32(d->tail[1]);
+}
+
+static void lfs_dir_tole32(struct lfs_disk_dir *d) {
+ d->rev = lfs_tole32(d->rev);
+ d->size = lfs_tole32(d->size);
+ d->tail[0] = lfs_tole32(d->tail[0]);
+ d->tail[1] = lfs_tole32(d->tail[1]);
+}
+
+static void lfs_entry_fromle32(struct lfs_disk_entry *d) {
+ d->u.dir[0] = lfs_fromle32(d->u.dir[0]);
+ d->u.dir[1] = lfs_fromle32(d->u.dir[1]);
+}
+
+static void lfs_entry_tole32(struct lfs_disk_entry *d) {
+ d->u.dir[0] = lfs_tole32(d->u.dir[0]);
+ d->u.dir[1] = lfs_tole32(d->u.dir[1]);
+}
+
+static void lfs_superblock_fromle32(struct lfs_disk_superblock *d) {
+ d->root[0] = lfs_fromle32(d->root[0]);
+ d->root[1] = lfs_fromle32(d->root[1]);
+ d->block_size = lfs_fromle32(d->block_size);
+ d->block_count = lfs_fromle32(d->block_count);
+ d->version = lfs_fromle32(d->version);
+}
+
+static void lfs_superblock_tole32(struct lfs_disk_superblock *d) {
+ d->root[0] = lfs_tole32(d->root[0]);
+ d->root[1] = lfs_tole32(d->root[1]);
+ d->block_size = lfs_tole32(d->block_size);
+ d->block_count = lfs_tole32(d->block_count);
+ d->version = lfs_tole32(d->version);
+}
+
+
+/// 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] == 0xffffffff || pair[1] == 0xffffffff;
+}
+
+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 inline bool lfs_pairsync(
+ 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 inline lfs_size_t lfs_entry_size(const lfs_entry_t *entry) {
+ return 4 + entry->d.elen + entry->d.alen + entry->d.nlen;
+}
+
+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;
+ }
+ }
+
+ // 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 && err != LFS_ERR_CORRUPT) {
+ return err;
+ }
+
+ if (err != LFS_ERR_CORRUPT) {
+ dir->d.rev = lfs_fromle32(dir->d.rev);
+ }
+
+ // set defaults
+ dir->d.rev += 1;
+ dir->d.size = sizeof(dir->d)+4;
+ dir->d.tail[0] = 0xffffffff;
+ dir->d.tail[1] = 0xffffffff;
+ 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));
+ lfs_dir_fromle32(&test);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ continue;
+ }
+ return err;
+ }
+
+ if (valid && lfs_scmp(test.rev, dir->d.rev) < 0) {
+ continue;
+ }
+
+ if ((0x7fffffff & test.size) < sizeof(test)+4 ||
+ (0x7fffffff & test.size) > lfs->cfg->block_size) {
+ continue;
+ }
+
+ uint32_t crc = 0xffffffff;
+ lfs_dir_tole32(&test);
+ lfs_crc(&crc, &test, sizeof(test));
+ lfs_dir_fromle32(&test);
+ err = lfs_bd_crc(lfs, tpair[i], sizeof(test),
+ (0x7fffffff & test.size) - sizeof(test), &crc);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ continue;
+ }
+ return err;
+ }
+
+ 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 %" PRIu32 " %" PRIu32 ,
+ tpair[0], tpair[1]);
+ return LFS_ERR_CORRUPT;
+ }
+
+ return 0;
+}
+
+struct lfs_region {
+ lfs_off_t oldoff;
+ lfs_size_t oldlen;
+ const void *newdata;
+ lfs_size_t newlen;
+};
+
+static int lfs_dir_commit(lfs_t *lfs, lfs_dir_t *dir,
+ const struct lfs_region *regions, int count) {
+ // increment revision count
+ dir->d.rev += 1;
+
+ // keep pairs in order such that pair[0] is most recent
+ lfs_pairswap(dir->pair);
+ for (int i = 0; i < count; i++) {
+ dir->d.size += regions[i].newlen - regions[i].oldlen;
+ }
+
+ const lfs_block_t oldpair[2] = {dir->pair[0], dir->pair[1]};
+ bool relocated = false;
+
+ while (true) {
+ if (true) {
+ int err = lfs_bd_erase(lfs, dir->pair[0]);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ uint32_t crc = 0xffffffff;
+ lfs_dir_tole32(&dir->d);
+ lfs_crc(&crc, &dir->d, sizeof(dir->d));
+ err = lfs_bd_prog(lfs, dir->pair[0], 0, &dir->d, sizeof(dir->d));
+ lfs_dir_fromle32(&dir->d);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ int i = 0;
+ lfs_off_t oldoff = sizeof(dir->d);
+ lfs_off_t newoff = sizeof(dir->d);
+ while (newoff < (0x7fffffff & dir->d.size)-4) {
+ if (i < count && regions[i].oldoff == oldoff) {
+ lfs_crc(&crc, regions[i].newdata, regions[i].newlen);
+ err = lfs_bd_prog(lfs, dir->pair[0],
+ newoff, regions[i].newdata, regions[i].newlen);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ oldoff += regions[i].oldlen;
+ newoff += regions[i].newlen;
+ i += 1;
+ } else {
+ uint8_t data;
+ err = lfs_bd_read(lfs, oldpair[1], oldoff, &data, 1);
+ if (err) {
+ return err;
+ }
+
+ lfs_crc(&crc, &data, 1);
+ err = lfs_bd_prog(lfs, dir->pair[0], newoff, &data, 1);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ oldoff += 1;
+ newoff += 1;
+ }
+ }
+
+ crc = lfs_tole32(crc);
+ err = lfs_bd_prog(lfs, dir->pair[0], newoff, &crc, 4);
+ crc = lfs_fromle32(crc);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ err = lfs_bd_sync(lfs);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ // successful commit, check checksum to make sure
+ uint32_t ncrc = 0xffffffff;
+ err = lfs_bd_crc(lfs, dir->pair[0], 0,
+ (0x7fffffff & dir->d.size)-4, &ncrc);
+ if (err) {
+ return err;
+ }
+
+ if (ncrc != crc) {
+ goto relocate;
+ }
+ }
+
+ break;
+relocate:
+ //commit was corrupted
+ LFS_DEBUG("Bad block at %" PRIu32, dir->pair[0]);
+
+ // drop caches and prepare to relocate block
+ relocated = true;
+ lfs_cache_drop(lfs, &lfs->pcache);
+
+ // can't relocate superblock, filesystem is now frozen
+ if (lfs_paircmp(oldpair, (const lfs_block_t[2]){0, 1}) == 0) {
+ LFS_WARN("Superblock %" PRIu32 " has become unwritable",
+ oldpair[0]);
+ return LFS_ERR_CORRUPT;
+ }
+
+ // relocate half of pair
+ int err = lfs_alloc(lfs, &dir->pair[0]);
+ if (err) {
+ return err;
+ }
+ }
+
+ if (relocated) {
+ // update references if we relocated
+ LFS_DEBUG("Relocating %" PRIu32 " %" PRIu32 " to %" PRIu32 " %" PRIu32,
+ oldpair[0], oldpair[1], dir->pair[0], dir->pair[1]);
+ int err = lfs_relocate(lfs, oldpair, dir->pair);
+ if (err) {
+ return err;
+ }
+ }
+
+ // shift over any directories that are affected
+ for (lfs_dir_t *d = lfs->dirs; d; d = d->next) {
+ if (lfs_paircmp(d->pair, dir->pair) == 0) {
+ d->pair[0] = dir->pair[0];
+ d->pair[1] = dir->pair[1];
+ }
+ }
+
+ return 0;
+}
+
+static int lfs_dir_update(lfs_t *lfs, lfs_dir_t *dir,
+ lfs_entry_t *entry, const void *data) {
+ lfs_entry_tole32(&entry->d);
+ int err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
+ {entry->off, sizeof(entry->d), &entry->d, sizeof(entry->d)},
+ {entry->off+sizeof(entry->d), entry->d.nlen, data, entry->d.nlen}
+ }, data ? 2 : 1);
+ lfs_entry_fromle32(&entry->d);
+ return err;
+}
+
+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 + lfs_entry_size(entry) <= lfs->cfg->block_size) {
+ entry->off = dir->d.size - 4;
+
+ lfs_entry_tole32(&entry->d);
+ int err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
+ {entry->off, 0, &entry->d, sizeof(entry->d)},
+ {entry->off, 0, data, entry->d.nlen}
+ }, 2);
+ lfs_entry_fromle32(&entry->d);
+ return err;
+ }
+
+ // we need to allocate a new dir block
+ if (!(0x80000000 & dir->d.size)) {
+ lfs_dir_t olddir = *dir;
+ int err = lfs_dir_alloc(lfs, dir);
+ if (err) {
+ return err;
+ }
+
+ dir->d.tail[0] = olddir.d.tail[0];
+ dir->d.tail[1] = olddir.d.tail[1];
+ entry->off = dir->d.size - 4;
+ lfs_entry_tole32(&entry->d);
+ err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
+ {entry->off, 0, &entry->d, sizeof(entry->d)},
+ {entry->off, 0, data, entry->d.nlen}
+ }, 2);
+ lfs_entry_fromle32(&entry->d);
+ if (err) {
+ return err;
+ }
+
+ olddir.d.size |= 0x80000000;
+ olddir.d.tail[0] = dir->pair[0];
+ olddir.d.tail[1] = dir->pair[1];
+ return lfs_dir_commit(lfs, &olddir, NULL, 0);
+ }
+
+ 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) {
+ // check if we should just drop the directory block
+ if ((dir->d.size & 0x7fffffff) == sizeof(dir->d)+4
+ + lfs_entry_size(entry)) {
+ lfs_dir_t pdir;
+ int res = lfs_pred(lfs, dir->pair, &pdir);
+ if (res < 0) {
+ return res;
+ }
+
+ if (pdir.d.size & 0x80000000) {
+ pdir.d.size &= dir->d.size | 0x7fffffff;
+ pdir.d.tail[0] = dir->d.tail[0];
+ pdir.d.tail[1] = dir->d.tail[1];
+ return lfs_dir_commit(lfs, &pdir, NULL, 0);
+ }
+ }
+
+ // shift out the entry
+ int err = lfs_dir_commit(lfs, dir, (struct lfs_region[]){
+ {entry->off, lfs_entry_size(entry), NULL, 0},
+ }, 1);
+ if (err) {
+ return err;
+ }
+
+ // shift over any files/directories that are affected
+ for (lfs_file_t *f = lfs->files; f; f = f->next) {
+ if (lfs_paircmp(f->pair, dir->pair) == 0) {
+ if (f->poff == entry->off) {
+ f->pair[0] = 0xffffffff;
+ f->pair[1] = 0xffffffff;
+ } else if (f->poff > entry->off) {
+ f->poff -= lfs_entry_size(entry);
+ }
+ }
+ }
+
+ for (lfs_dir_t *d = lfs->dirs; d; d = d->next) {
+ if (lfs_paircmp(d->pair, dir->pair) == 0) {
+ if (d->off > entry->off) {
+ d->off -= lfs_entry_size(entry);
+ d->pos -= lfs_entry_size(entry);
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int lfs_dir_next(lfs_t *lfs, lfs_dir_t *dir, lfs_entry_t *entry) {
+ while (dir->off + sizeof(entry->d) > (0x7fffffff & dir->d.size)-4) {
+ 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) + 4;
+ }
+
+ int err = lfs_bd_read(lfs, dir->pair[0], dir->off,
+ &entry->d, sizeof(entry->d));
+ lfs_entry_fromle32(&entry->d);
+ if (err) {
+ return err;
+ }
+
+ entry->off = dir->off;
+ dir->off += lfs_entry_size(entry);
+ dir->pos += lfs_entry_size(entry);
+ 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;
+ entry->d.type = LFS_TYPE_DIR;
+ entry->d.elen = sizeof(entry->d) - 4;
+ entry->d.alen = 0;
+ entry->d.nlen = 0;
+ entry->d.u.dir[0] = lfs->root[0];
+ entry->d.u.dir[1] = lfs->root[1];
+
+ 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;
+ }
+
+ // found path
+ if (pathname[0] == '\0') {
+ return 0;
+ }
+
+ // update what we've found
+ *path = pathname;
+
+ // 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;
+ }
+
+ // find entry matching name
+ while (true) {
+ err = lfs_dir_next(lfs, dir, entry);
+ if (err) {
+ return err;
+ }
+
+ if (((0x7f & entry->d.type) != LFS_TYPE_REG &&
+ (0x7f & entry->d.type) != LFS_TYPE_DIR) ||
+ entry->d.nlen != pathlen) {
+ continue;
+ }
+
+ int res = lfs_bd_cmp(lfs, dir->pair[0],
+ entry->off + 4+entry->d.elen+entry->d.alen,
+ pathname, pathlen);
+ if (res < 0) {
+ return res;
+ }
+
+ // found match
+ if (res) {
+ break;
+ }
+ }
+
+ // check that entry has not been moved
+ if (entry->d.type & 0x80) {
+ int moved = lfs_moved(lfs, &entry->d.u);
+ if (moved < 0 || moved) {
+ return (moved < 0) ? moved : LFS_ERR_NOENT;
+ }
+
+ entry->d.type &= ~0x80;
+ }
+
+ // to next name
+ pathname += pathlen;
+ }
+}
+
+
+/// Top level directory operations ///
+int lfs_mkdir(lfs_t *lfs, const char *path) {
+ // deorphan if we haven't yet, needed at most once after poweron
+ if (!lfs->deorphaned) {
+ int err = lfs_deorphan(lfs);
+ if (err) {
+ return err;
+ }
+ }
+
+ // fetch parent directory
+ lfs_dir_t cwd;
+ lfs_entry_t entry;
+ int err = lfs_dir_find(lfs, &cwd, &entry, &path);
+ if (err != LFS_ERR_NOENT || strchr(path, '/') != NULL) {
+ return err ? err : LFS_ERR_EXIST;
+ }
+
+ // build up new directory
+ lfs_alloc_ack(lfs);
+
+ 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, 0);
+ if (err) {
+ return err;
+ }
+
+ entry.d.type = LFS_TYPE_DIR;
+ entry.d.elen = sizeof(entry.d) - 4;
+ entry.d.alen = 0;
+ entry.d.nlen = 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];
+
+ err = lfs_dir_append(lfs, &cwd, &entry, path);
+ if (err) {
+ return err;
+ }
+
+ lfs_alloc_ack(lfs);
+ return 0;
+}
+
+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];
+
+ lfs_entry_t entry;
+ int 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);
+
+ // add to list of directories
+ dir->next = lfs->dirs;
+ lfs->dirs = dir;
+
+ return 0;
+}
+
+int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir) {
+ // remove from list of directories
+ for (lfs_dir_t **p = &lfs->dirs; *p; p = &(*p)->next) {
+ if (*p == dir) {
+ *p = dir->next;
+ break;
+ }
+ }
+
+ 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;
+ while (true) {
+ int err = lfs_dir_next(lfs, dir, &entry);
+ if (err) {
+ return (err == LFS_ERR_NOENT) ? 0 : err;
+ }
+
+ if ((0x7f & entry.d.type) != LFS_TYPE_REG &&
+ (0x7f & entry.d.type) != LFS_TYPE_DIR) {
+ continue;
+ }
+
+ // check that entry has not been moved
+ if (entry.d.type & 0x80) {
+ int moved = lfs_moved(lfs, &entry.d.u);
+ if (moved < 0) {
+ return moved;
+ }
+
+ if (moved) {
+ continue;
+ }
+
+ entry.d.type &= ~0x80;
+ }
+
+ break;
+ }
+
+ info->type = entry.d.type;
+ if (info->type == LFS_TYPE_REG) {
+ info->size = entry.d.u.file.size;
+ }
+
+ int err = lfs_bd_read(lfs, dir->pair[0],
+ entry.off + 4+entry.d.elen+entry.d.alen,
+ info->name, entry.d.nlen);
+ 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;
+ }
+
+ 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) {
+ (void)lfs;
+ 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;
+}
+
+
+/// File index list operations ///
+static int lfs_ctz_index(lfs_t *lfs, lfs_off_t *off) {
+ lfs_off_t size = *off;
+ lfs_off_t b = lfs->cfg->block_size - 2*4;
+ lfs_off_t i = size / b;
+ if (i == 0) {
+ return 0;
+ }
+
+ i = (size - 4*(lfs_popc(i-1)+2)) / b;
+ *off = size - b*i - 4*lfs_popc(i);
+ return i;
+}
+
+static int lfs_ctz_find(lfs_t *lfs,
+ lfs_cache_t *rcache, const lfs_cache_t *pcache,
+ lfs_block_t head, lfs_size_t size,
+ lfs_size_t pos, lfs_block_t *block, lfs_off_t *off) {
+ if (size == 0) {
+ *block = 0xffffffff;
+ *off = 0;
+ return 0;
+ }
+
+ lfs_off_t current = lfs_ctz_index(lfs, &(lfs_off_t){size-1});
+ lfs_off_t target = lfs_ctz_index(lfs, &pos);
+
+ while (current > target) {
+ lfs_size_t skip = lfs_min(
+ lfs_npw2(current-target+1) - 1,
+ lfs_ctz(current));
+
+ int err = lfs_cache_read(lfs, rcache, pcache, head, 4*skip, &head, 4);
+ head = lfs_fromle32(head);
+ if (err) {
+ return err;
+ }
+
+ LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
+ current -= 1 << skip;
+ }
+
+ *block = head;
+ *off = pos;
+ return 0;
+}
+
+static int lfs_ctz_extend(lfs_t *lfs,
+ lfs_cache_t *rcache, lfs_cache_t *pcache,
+ lfs_block_t head, lfs_size_t size,
+ lfs_block_t *block, lfs_off_t *off) {
+ while (true) {
+ // go ahead and grab a block
+ lfs_block_t nblock;
+ int err = lfs_alloc(lfs, &nblock);
+ if (err) {
+ return err;
+ }
+ LFS_ASSERT(nblock >= 2 && nblock <= lfs->cfg->block_count);
+
+ if (true) {
+ err = lfs_bd_erase(lfs, nblock);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ if (size == 0) {
+ *block = nblock;
+ *off = 0;
+ return 0;
+ }
+
+ size -= 1;
+ lfs_off_t index = lfs_ctz_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;
+ err = lfs_cache_read(lfs, rcache, NULL,
+ head, i, &data, 1);
+ if (err) {
+ return err;
+ }
+
+ err = lfs_cache_prog(lfs, pcache, rcache,
+ nblock, i, &data, 1);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+ }
+
+ *block = nblock;
+ *off = size;
+ return 0;
+ }
+
+ // append block
+ index += 1;
+ lfs_size_t skips = lfs_ctz(index) + 1;
+
+ for (lfs_off_t i = 0; i < skips; i++) {
+ head = lfs_tole32(head);
+ err = lfs_cache_prog(lfs, pcache, rcache,
+ nblock, 4*i, &head, 4);
+ head = lfs_fromle32(head);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ if (i != skips-1) {
+ err = lfs_cache_read(lfs, rcache, NULL,
+ head, 4*i, &head, 4);
+ head = lfs_fromle32(head);
+ if (err) {
+ return err;
+ }
+ }
+
+ LFS_ASSERT(head >= 2 && head <= lfs->cfg->block_count);
+ }
+
+ *block = nblock;
+ *off = 4*skips;
+ return 0;
+ }
+
+relocate:
+ LFS_DEBUG("Bad block at %" PRIu32, nblock);
+
+ // just clear cache and try a new block
+ lfs_cache_drop(lfs, &lfs->pcache);
+ }
+}
+
+static int lfs_ctz_traverse(lfs_t *lfs,
+ lfs_cache_t *rcache, const lfs_cache_t *pcache,
+ 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_ctz_index(lfs, &(lfs_off_t){size-1});
+
+ while (true) {
+ int err = cb(data, head);
+ if (err) {
+ return err;
+ }
+
+ if (index == 0) {
+ return 0;
+ }
+
+ lfs_block_t heads[2];
+ int count = 2 - (index & 1);
+ err = lfs_cache_read(lfs, rcache, pcache, head, 0, &heads, count*4);
+ heads[0] = lfs_fromle32(heads[0]);
+ heads[1] = lfs_fromle32(heads[1]);
+ if (err) {
+ return err;
+ }
+
+ for (int i = 0; i < count-1; i++) {
+ err = cb(data, heads[i]);
+ if (err) {
+ return err;
+ }
+ }
+
+ head = heads[count-1];
+ index -= count;
+ }
+}
+
+
+/// Top level file operations ///
+int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
+ const char *path, int flags,
+ const struct lfs_file_config *cfg) {
+ // deorphan if we haven't yet, needed at most once after poweron
+ if ((flags & 3) != LFS_O_RDONLY && !lfs->deorphaned) {
+ int err = lfs_deorphan(lfs);
+ if (err) {
+ return err;
+ }
+ }
+
+ // allocate entry for file if it doesn't exist
+ lfs_dir_t cwd;
+ lfs_entry_t entry;
+ int err = lfs_dir_find(lfs, &cwd, &entry, &path);
+ if (err && (err != LFS_ERR_NOENT || strchr(path, '/') != NULL)) {
+ 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.elen = sizeof(entry.d) - 4;
+ entry.d.alen = 0;
+ entry.d.nlen = strlen(path);
+ entry.d.u.file.head = 0xffffffff;
+ 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_EXIST;
+ }
+
+ // setup file struct
+ file->cfg = cfg;
+ file->pair[0] = cwd.pair[0];
+ file->pair[1] = cwd.pair[1];
+ file->poff = entry.off;
+ file->head = entry.d.u.file.head;
+ file->size = entry.d.u.file.size;
+ file->flags = flags;
+ file->pos = 0;
+
+ if (flags & LFS_O_TRUNC) {
+ if (file->size != 0) {
+ file->flags |= LFS_F_DIRTY;
+ }
+ file->head = 0xffffffff;
+ file->size = 0;
+ }
+
+ // allocate buffer if needed
+ file->cache.block = 0xffffffff;
+ if (file->cfg && file->cfg->buffer) {
+ file->cache.buffer = file->cfg->buffer;
+ } else if (lfs->cfg->file_buffer) {
+ if (lfs->files) {
+ // already in use
+ return LFS_ERR_NOMEM;
+ }
+ file->cache.buffer = lfs->cfg->file_buffer;
+ } else if ((file->flags & 3) == LFS_O_RDONLY) {
+ file->cache.buffer = lfs_malloc(lfs->cfg->read_size);
+ if (!file->cache.buffer) {
+ return LFS_ERR_NOMEM;
+ }
+ } else {
+ file->cache.buffer = lfs_malloc(lfs->cfg->prog_size);
+ if (!file->cache.buffer) {
+ return LFS_ERR_NOMEM;
+ }
+ }
+
+ // zero to avoid information leak
+ lfs_cache_zero(lfs, &file->cache);
+
+ // add to list of files
+ file->next = lfs->files;
+ lfs->files = file;
+
+ return 0;
+}
+
+int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
+ const char *path, int flags) {
+ return lfs_file_opencfg(lfs, file, path, flags, NULL);
+}
+
+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;
+ }
+ }
+
+ // clean up memory
+ if (!(file->cfg && file->cfg->buffer) && !lfs->cfg->file_buffer) {
+ lfs_free(file->cache.buffer);
+ }
+
+ return err;
+}
+
+static int lfs_file_relocate(lfs_t *lfs, lfs_file_t *file) {
+relocate:
+ LFS_DEBUG("Bad block at %" PRIu32, file->block);
+
+ // just relocate what exists into new block
+ lfs_block_t nblock;
+ int err = lfs_alloc(lfs, &nblock);
+ if (err) {
+ return err;
+ }
+
+ err = lfs_bd_erase(lfs, nblock);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ // either read from dirty cache or disk
+ for (lfs_off_t i = 0; i < file->off; i++) {
+ uint8_t data;
+ err = lfs_cache_read(lfs, &lfs->rcache, &file->cache,
+ file->block, i, &data, 1);
+ if (err) {
+ return err;
+ }
+
+ err = lfs_cache_prog(lfs, &lfs->pcache, &lfs->rcache,
+ nblock, i, &data, 1);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+ }
+
+ // copy over new state of file
+ memcpy(file->cache.buffer, lfs->pcache.buffer, lfs->cfg->prog_size);
+ file->cache.block = lfs->pcache.block;
+ file->cache.off = lfs->pcache.off;
+ lfs_cache_zero(lfs, &lfs->pcache);
+
+ file->block = nblock;
+ return 0;
+}
+
+static int lfs_file_flush(lfs_t *lfs, lfs_file_t *file) {
+ if (file->flags & LFS_F_READING) {
+ // just drop read cache
+ lfs_cache_drop(lfs, &file->cache);
+ file->flags &= ~LFS_F_READING;
+ }
+
+ if (file->flags & LFS_F_WRITING) {
+ 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,
+ .cache = lfs->rcache,
+ };
+ lfs_cache_drop(lfs, &lfs->rcache);
+
+ while (file->pos < file->size) {
+ // copy over a byte at a time, leave it up to caching
+ // to make this efficient
+ 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;
+ }
+
+ // keep our reference to the rcache in sync
+ if (lfs->rcache.block != 0xffffffff) {
+ lfs_cache_drop(lfs, &orig.cache);
+ lfs_cache_drop(lfs, &lfs->rcache);
+ }
+ }
+
+ // write out what we have
+ while (true) {
+ int err = lfs_cache_flush(lfs, &file->cache, &lfs->rcache);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ return err;
+ }
+
+ break;
+relocate:
+ err = lfs_file_relocate(lfs, file);
+ if (err) {
+ return err;
+ }
+ }
+
+ // actual file updates
+ file->head = file->block;
+ file->size = file->pos;
+ file->flags &= ~LFS_F_WRITING;
+ file->flags |= LFS_F_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_F_DIRTY) &&
+ !(file->flags & LFS_F_ERRED) &&
+ !lfs_pairisnull(file->pair)) {
+ // update dir entry
+ lfs_dir_t cwd;
+ err = lfs_dir_fetch(lfs, &cwd, file->pair);
+ if (err) {
+ return err;
+ }
+
+ lfs_entry_t entry = {.off = file->poff};
+ err = lfs_bd_read(lfs, cwd.pair[0], entry.off,
+ &entry.d, sizeof(entry.d));
+ lfs_entry_fromle32(&entry.d);
+ if (err) {
+ return err;
+ }
+
+ LFS_ASSERT(entry.d.type == LFS_TYPE_REG);
+ entry.d.u.file.head = file->head;
+ entry.d.u.file.size = file->size;
+
+ err = lfs_dir_update(lfs, &cwd, &entry, NULL);
+ if (err) {
+ return err;
+ }
+
+ file->flags &= ~LFS_F_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_BADF;
+ }
+
+ if (file->flags & LFS_F_WRITING) {
+ // flush out any writes
+ int err = lfs_file_flush(lfs, file);
+ if (err) {
+ return err;
+ }
+ }
+
+ if (file->pos >= file->size) {
+ // eof if past end
+ return 0;
+ }
+
+ size = lfs_min(size, file->size - file->pos);
+ nsize = size;
+
+ while (nsize > 0) {
+ // check if we need a new block
+ if (!(file->flags & LFS_F_READING) ||
+ file->off == lfs->cfg->block_size) {
+ int err = lfs_ctz_find(lfs, &file->cache, NULL,
+ file->head, file->size,
+ file->pos, &file->block, &file->off);
+ if (err) {
+ return err;
+ }
+
+ file->flags |= LFS_F_READING;
+ }
+
+ // read as much as we can in current block
+ lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->off);
+ int err = lfs_cache_read(lfs, &file->cache, NULL,
+ file->block, file->off, data, diff);
+ if (err) {
+ return err;
+ }
+
+ file->pos += diff;
+ file->off += 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_BADF;
+ }
+
+ if (file->flags & LFS_F_READING) {
+ // 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;
+ }
+
+ if (!(file->flags & LFS_F_WRITING) && file->pos > file->size) {
+ // fill with zeros
+ lfs_off_t pos = file->pos;
+ file->pos = file->size;
+
+ while (file->pos < pos) {
+ lfs_ssize_t res = lfs_file_write(lfs, file, &(uint8_t){0}, 1);
+ if (res < 0) {
+ return res;
+ }
+ }
+ }
+
+ while (nsize > 0) {
+ // check if we need a new block
+ if (!(file->flags & LFS_F_WRITING) ||
+ file->off == lfs->cfg->block_size) {
+ if (!(file->flags & LFS_F_WRITING) && file->pos > 0) {
+ // find out which block we're extending from
+ int err = lfs_ctz_find(lfs, &file->cache, NULL,
+ file->head, file->size,
+ file->pos-1, &file->block, &file->off);
+ if (err) {
+ file->flags |= LFS_F_ERRED;
+ return err;
+ }
+
+ // mark cache as dirty since we may have read data into it
+ lfs_cache_zero(lfs, &file->cache);
+ }
+
+ // extend file with new blocks
+ lfs_alloc_ack(lfs);
+ int err = lfs_ctz_extend(lfs, &lfs->rcache, &file->cache,
+ file->block, file->pos,
+ &file->block, &file->off);
+ if (err) {
+ file->flags |= LFS_F_ERRED;
+ return err;
+ }
+
+ file->flags |= LFS_F_WRITING;
+ }
+
+ // program as much as we can in current block
+ lfs_size_t diff = lfs_min(nsize, lfs->cfg->block_size - file->off);
+ while (true) {
+ int err = lfs_cache_prog(lfs, &file->cache, &lfs->rcache,
+ file->block, file->off, data, diff);
+ if (err) {
+ if (err == LFS_ERR_CORRUPT) {
+ goto relocate;
+ }
+ file->flags |= LFS_F_ERRED;
+ return err;
+ }
+
+ break;
+relocate:
+ err = lfs_file_relocate(lfs, file);
+ if (err) {
+ file->flags |= LFS_F_ERRED;
+ return err;
+ }
+ }
+
+ file->pos += diff;
+ file->off += diff;
+ data += diff;
+ nsize -= diff;
+
+ lfs_alloc_ack(lfs);
+ }
+
+ file->flags &= ~LFS_F_ERRED;
+ 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
+ if (whence == LFS_SEEK_SET) {
+ file->pos = off;
+ } else if (whence == LFS_SEEK_CUR) {
+ if (off < 0 && (lfs_off_t)-off > file->pos) {
+ return LFS_ERR_INVAL;
+ }
+
+ file->pos = file->pos + off;
+ } else if (whence == LFS_SEEK_END) {
+ if (off < 0 && (lfs_off_t)-off > file->size) {
+ return LFS_ERR_INVAL;
+ }
+
+ file->pos = file->size + off;
+ }
+
+ return file->pos;
+}
+
+int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size) {
+ if ((file->flags & 3) == LFS_O_RDONLY) {
+ return LFS_ERR_BADF;
+ }
+
+ lfs_off_t oldsize = lfs_file_size(lfs, file);
+ if (size < oldsize) {
+ // need to flush since directly changing metadata
+ int err = lfs_file_flush(lfs, file);
+ if (err) {
+ return err;
+ }
+
+ // lookup new head in ctz skip list
+ err = lfs_ctz_find(lfs, &file->cache, NULL,
+ file->head, file->size,
+ size, &file->head, &(lfs_off_t){0});
+ if (err) {
+ return err;
+ }
+
+ file->size = size;
+ file->flags |= LFS_F_DIRTY;
+ } else if (size > oldsize) {
+ lfs_off_t pos = file->pos;
+
+ // flush+seek if not already at end
+ if (file->pos != oldsize) {
+ int err = lfs_file_seek(lfs, file, 0, LFS_SEEK_END);
+ if (err < 0) {
+ return err;
+ }
+ }
+
+ // fill with zeros
+ while (file->pos < size) {
+ lfs_ssize_t res = lfs_file_write(lfs, file, &(uint8_t){0}, 1);
+ if (res < 0) {
+ return res;
+ }
+ }
+
+ // restore pos
+ int err = lfs_file_seek(lfs, file, pos, LFS_SEEK_SET);
+ if (err < 0) {
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file) {
+ (void)lfs;
+ 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) {
+ (void)lfs;
+ if (file->flags & LFS_F_WRITING) {
+ return lfs_max(file->pos, file->size);
+ } else {
+ return file->size;
+ }
+}
+
+
+/// General fs operations ///
+int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info) {
+ lfs_dir_t cwd;
+ lfs_entry_t entry;
+ int err = lfs_dir_find(lfs, &cwd, &entry, &path);
+ if (err) {
+ return err;
+ }
+
+ memset(info, 0, sizeof(*info));
+ info->type = entry.d.type;
+ if (info->type == LFS_TYPE_REG) {
+ info->size = entry.d.u.file.size;
+ }
+
+ if (lfs_paircmp(entry.d.u.dir, lfs->root) == 0) {
+ strcpy(info->name, "/");
+ } else {
+ err = lfs_bd_read(lfs, cwd.pair[0],
+ entry.off + 4+entry.d.elen+entry.d.alen,
+ info->name, entry.d.nlen);
+ if (err) {
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+int lfs_remove(lfs_t *lfs, const char *path) {
+ // deorphan if we haven't yet, needed at most once after poweron
+ if (!lfs->deorphaned) {
+ int err = lfs_deorphan(lfs);
+ if (err) {
+ return err;
+ }
+ }
+
+ lfs_dir_t cwd;
+ lfs_entry_t entry;
+ int 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
+ err = lfs_dir_fetch(lfs, &dir, entry.d.u.dir);
+ if (err) {
+ return err;
+ } else if (dir.d.size != sizeof(dir.d)+4) {
+ return LFS_ERR_NOTEMPTY;
+ }
+ }
+
+ // remove the entry
+ err = lfs_dir_remove(lfs, &cwd, &entry);
+ if (err) {
+ return err;
+ }
+
+ // if we were a directory, find pred, replace tail
+ if (entry.d.type == LFS_TYPE_DIR) {
+ int res = lfs_pred(lfs, dir.pair, &cwd);
+ if (res < 0) {
+ return res;
+ }
+
+ LFS_ASSERT(res); // must have pred
+ cwd.d.tail[0] = dir.d.tail[0];
+ cwd.d.tail[1] = dir.d.tail[1];
+
+ err = lfs_dir_commit(lfs, &cwd, NULL, 0);
+ if (err) {
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath) {
+ // deorphan if we haven't yet, needed at most once after poweron
+ if (!lfs->deorphaned) {
+ int err = lfs_deorphan(lfs);
+ if (err) {
+ return err;
+ }
+ }
+
+ // find old entry
+ lfs_dir_t oldcwd;
+ lfs_entry_t oldentry;
+ int err = lfs_dir_find(lfs, &oldcwd, &oldentry, &oldpath);
+ if (err) {
+ return err;
+ }
+
+ // allocate new entry
+ lfs_dir_t newcwd;
+ lfs_entry_t preventry;
+ err = lfs_dir_find(lfs, &newcwd, &preventry, &newpath);
+ if (err && (err != LFS_ERR_NOENT || strchr(newpath, '/') != NULL)) {
+ return err;
+ }
+
+ bool prevexists = (err != LFS_ERR_NOENT);
+ bool samepair = (lfs_paircmp(oldcwd.pair, newcwd.pair) == 0);
+
+ // must have same type
+ if (prevexists && preventry.d.type != oldentry.d.type) {
+ return LFS_ERR_ISDIR;
+ }
+
+ 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
+ err = lfs_dir_fetch(lfs, &dir, preventry.d.u.dir);
+ if (err) {
+ return err;
+ } else if (dir.d.size != sizeof(dir.d)+4) {
+ return LFS_ERR_NOTEMPTY;
+ }
+ }
+
+ // mark as moving
+ oldentry.d.type |= 0x80;
+ err = lfs_dir_update(lfs, &oldcwd, &oldentry, NULL);
+ if (err) {
+ return err;
+ }
+
+ // update pair if newcwd == oldcwd
+ if (samepair) {
+ newcwd = oldcwd;
+ }
+
+ // move to new location
+ lfs_entry_t newentry = preventry;
+ newentry.d = oldentry.d;
+ newentry.d.type &= ~0x80;
+ newentry.d.nlen = strlen(newpath);
+
+ if (prevexists) {
+ err = lfs_dir_update(lfs, &newcwd, &newentry, newpath);
+ if (err) {
+ return err;
+ }
+ } else {
+ err = lfs_dir_append(lfs, &newcwd, &newentry, newpath);
+ if (err) {
+ return err;
+ }
+ }
+
+ // update pair if newcwd == oldcwd
+ if (samepair) {
+ oldcwd = newcwd;
+ }
+
+ // remove old entry
+ err = lfs_dir_remove(lfs, &oldcwd, &oldentry);
+ if (err) {
+ return err;
+ }
+
+ // if we were a directory, find pred, replace tail
+ if (prevexists && preventry.d.type == LFS_TYPE_DIR) {
+ int res = lfs_pred(lfs, dir.pair, &newcwd);
+ if (res < 0) {
+ return res;
+ }
+
+ LFS_ASSERT(res); // must have pred
+ newcwd.d.tail[0] = dir.d.tail[0];
+ newcwd.d.tail[1] = dir.d.tail[1];
+
+ err = lfs_dir_commit(lfs, &newcwd, NULL, 0);
+ if (err) {
+ return err;
+ }
+ }
+
+ return 0;
+}
+
+
+/// Filesystem operations ///
+static void lfs_deinit(lfs_t *lfs) {
+ // free allocated memory
+ if (!lfs->cfg->read_buffer) {
+ lfs_free(lfs->rcache.buffer);
+ }
+
+ if (!lfs->cfg->prog_buffer) {
+ lfs_free(lfs->pcache.buffer);
+ }
+
+ if (!lfs->cfg->lookahead_buffer) {
+ lfs_free(lfs->free.buffer);
+ }
+}
+
+static int lfs_init(lfs_t *lfs, const struct lfs_config *cfg) {
+ lfs->cfg = cfg;
+
+ // setup read cache
+ if (lfs->cfg->read_buffer) {
+ lfs->rcache.buffer = lfs->cfg->read_buffer;
+ } else {
+ lfs->rcache.buffer = lfs_malloc(lfs->cfg->read_size);
+ if (!lfs->rcache.buffer) {
+ goto cleanup;
+ }
+ }
+
+ // setup program cache
+ if (lfs->cfg->prog_buffer) {
+ lfs->pcache.buffer = lfs->cfg->prog_buffer;
+ } else {
+ lfs->pcache.buffer = lfs_malloc(lfs->cfg->prog_size);
+ if (!lfs->pcache.buffer) {
+ goto cleanup;
+ }
+ }
+
+ // zero to avoid information leaks
+ lfs_cache_zero(lfs, &lfs->rcache);
+ lfs_cache_zero(lfs, &lfs->pcache);
+
+ // setup lookahead, round down to nearest 32-bits
+ LFS_ASSERT(lfs->cfg->lookahead % 32 == 0);
+ LFS_ASSERT(lfs->cfg->lookahead > 0);
+ if (lfs->cfg->lookahead_buffer) {
+ lfs->free.buffer = lfs->cfg->lookahead_buffer;
+ } else {
+ lfs->free.buffer = lfs_malloc(lfs->cfg->lookahead/8);
+ if (!lfs->free.buffer) {
+ goto cleanup;
+ }
+ }
+
+ // check that program and read sizes are multiples of the block size
+ LFS_ASSERT(lfs->cfg->prog_size % lfs->cfg->read_size == 0);
+ LFS_ASSERT(lfs->cfg->block_size % lfs->cfg->prog_size == 0);
+
+ // check that the block size is large enough to fit ctz pointers
+ LFS_ASSERT(4*lfs_npw2(0xffffffff / (lfs->cfg->block_size-2*4))
+ <= lfs->cfg->block_size);
+
+ // setup default state
+ lfs->root[0] = 0xffffffff;
+ lfs->root[1] = 0xffffffff;
+ lfs->files = NULL;
+ lfs->dirs = NULL;
+ lfs->deorphaned = false;
+
+ return 0;
+
+cleanup:
+ lfs_deinit(lfs);
+ return LFS_ERR_NOMEM;
+}
+
+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.buffer, 0, lfs->cfg->lookahead/8);
+ lfs->free.off = 0;
+ lfs->free.size = lfs_min(lfs->cfg->lookahead, lfs->cfg->block_count);
+ lfs->free.i = 0;
+ lfs_alloc_ack(lfs);
+
+ // create superblock dir
+ lfs_dir_t superdir;
+ err = lfs_dir_alloc(lfs, &superdir);
+ if (err) {
+ goto cleanup;
+ }
+
+ // write root directory
+ lfs_dir_t root;
+ err = lfs_dir_alloc(lfs, &root);
+ if (err) {
+ goto cleanup;
+ }
+
+ err = lfs_dir_commit(lfs, &root, NULL, 0);
+ if (err) {
+ goto cleanup;
+ }
+
+ 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.elen = sizeof(superblock.d) - sizeof(superblock.d.magic) - 4,
+ .d.nlen = sizeof(superblock.d.magic),
+ .d.version = LFS_DISK_VERSION,
+ .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) + sizeof(superblock.d) + 4;
+
+ // write both pairs to be safe
+ lfs_superblock_tole32(&superblock.d);
+ bool valid = false;
+ for (int i = 0; i < 2; i++) {
+ err = lfs_dir_commit(lfs, &superdir, (struct lfs_region[]){
+ {sizeof(superdir.d), sizeof(superblock.d),
+ &superblock.d, sizeof(superblock.d)}
+ }, 1);
+ if (err && err != LFS_ERR_CORRUPT) {
+ goto cleanup;
+ }
+
+ valid = valid || !err;
+ }
+
+ if (!valid) {
+ err = LFS_ERR_CORRUPT;
+ goto cleanup;
+ }
+
+ // sanity check that fetch works
+ err = lfs_dir_fetch(lfs, &superdir, (const lfs_block_t[2]){0, 1});
+ if (err) {
+ goto cleanup;
+ }
+
+ lfs_alloc_ack(lfs);
+
+cleanup:
+ lfs_deinit(lfs);
+ return err;
+}
+
+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.off = 0;
+ lfs->free.size = 0;
+ lfs->free.i = 0;
+ lfs_alloc_ack(lfs);
+
+ // 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_ERR_CORRUPT) {
+ goto cleanup;
+ }
+
+ if (!err) {
+ err = lfs_bd_read(lfs, dir.pair[0], sizeof(dir.d),
+ &superblock.d, sizeof(superblock.d));
+ lfs_superblock_fromle32(&superblock.d);
+ if (err) {
+ goto cleanup;
+ }
+
+ lfs->root[0] = superblock.d.root[0];
+ lfs->root[1] = superblock.d.root[1];
+ }
+
+ if (err || memcmp(superblock.d.magic, "littlefs", 8) != 0) {
+ LFS_ERROR("Invalid superblock at %d %d", 0, 1);
+ err = LFS_ERR_CORRUPT;
+ goto cleanup;
+ }
+
+ uint16_t major_version = (0xffff & (superblock.d.version >> 16));
+ uint16_t minor_version = (0xffff & (superblock.d.version >> 0));
+ if ((major_version != LFS_DISK_VERSION_MAJOR ||
+ minor_version > LFS_DISK_VERSION_MINOR)) {
+ LFS_ERROR("Invalid version %d.%d", major_version, minor_version);
+ err = LFS_ERR_INVAL;
+ goto cleanup;
+ }
+
+ return 0;
+
+cleanup:
+
+ lfs_deinit(lfs);
+ return err;
+}
+
+int lfs_umount(lfs_t *lfs) {
+ lfs_deinit(lfs);
+ return 0;
+}
+
+
+/// Littlefs specific operations ///
+int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data) {
+ if (lfs_pairisnull(lfs->root)) {
+ return 0;
+ }
+
+ // 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 (dir.off + sizeof(entry.d) <= (0x7fffffff & dir.d.size)-4) {
+ err = lfs_bd_read(lfs, dir.pair[0], dir.off,
+ &entry.d, sizeof(entry.d));
+ lfs_entry_fromle32(&entry.d);
+ if (err) {
+ return err;
+ }
+
+ dir.off += lfs_entry_size(&entry);
+ if ((0x70 & entry.d.type) == (0x70 & LFS_TYPE_REG)) {
+ err = lfs_ctz_traverse(lfs, &lfs->rcache, NULL,
+ 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_F_DIRTY) {
+ int err = lfs_ctz_traverse(lfs, &lfs->rcache, &f->cache,
+ f->head, f->size, cb, data);
+ if (err) {
+ return err;
+ }
+ }
+
+ if (f->flags & LFS_F_WRITING) {
+ int err = lfs_ctz_traverse(lfs, &lfs->rcache, &f->cache,
+ f->block, f->pos, cb, data);
+ if (err) {
+ return err;
+ }
+ }
+ }
+
+ return 0;
+}
+
+static int lfs_pred(lfs_t *lfs, const lfs_block_t dir[2], lfs_dir_t *pdir) {
+ if (lfs_pairisnull(lfs->root)) {
+ return 0;
+ }
+
+ // iterate over all directory directory entries
+ int err = lfs_dir_fetch(lfs, pdir, (const lfs_block_t[2]){0, 1});
+ if (err) {
+ return err;
+ }
+
+ while (!lfs_pairisnull(pdir->d.tail)) {
+ if (lfs_paircmp(pdir->d.tail, dir) == 0) {
+ return true;
+ }
+
+ err = lfs_dir_fetch(lfs, pdir, pdir->d.tail);
+ if (err) {
+ return err;
+ }
+ }
+
+ return false;
+}
+
+static int lfs_parent(lfs_t *lfs, const lfs_block_t dir[2],
+ lfs_dir_t *parent, lfs_entry_t *entry) {
+ if (lfs_pairisnull(lfs->root)) {
+ return 0;
+ }
+
+ parent->d.tail[0] = 0;
+ parent->d.tail[1] = 1;
+
+ // iterate over all directory directory entries
+ while (!lfs_pairisnull(parent->d.tail)) {
+ int err = lfs_dir_fetch(lfs, parent, parent->d.tail);
+ if (err) {
+ return err;
+ }
+
+ while (true) {
+ err = lfs_dir_next(lfs, parent, entry);
+ if (err && err != LFS_ERR_NOENT) {
+ return err;
+ }
+
+ if (err == LFS_ERR_NOENT) {
+ break;
+ }
+
+ if (((0x70 & entry->d.type) == (0x70 & LFS_TYPE_DIR)) &&
+ lfs_paircmp(entry->d.u.dir, dir) == 0) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
+static int lfs_moved(lfs_t *lfs, const void *e) {
+ if (lfs_pairisnull(lfs->root)) {
+ return 0;
+ }
+
+ // skip superblock
+ lfs_dir_t cwd;
+ int err = lfs_dir_fetch(lfs, &cwd, (const lfs_block_t[2]){0, 1});
+ if (err) {
+ return err;
+ }
+
+ // iterate over all directory directory entries
+ lfs_entry_t entry;
+ while (!lfs_pairisnull(cwd.d.tail)) {
+ err = lfs_dir_fetch(lfs, &cwd, cwd.d.tail);
+ if (err) {
+ return err;
+ }
+
+ while (true) {
+ err = lfs_dir_next(lfs, &cwd, &entry);
+ if (err && err != LFS_ERR_NOENT) {
+ return err;
+ }
+
+ if (err == LFS_ERR_NOENT) {
+ break;
+ }
+
+ if (!(0x80 & entry.d.type) &&
+ memcmp(&entry.d.u, e, sizeof(entry.d.u)) == 0) {
+ return true;
+ }
+ }
+ }
+
+ return false;
+}
+
+static int lfs_relocate(lfs_t *lfs,
+ const lfs_block_t oldpair[2], const lfs_block_t newpair[2]) {
+ // find parent
+ lfs_dir_t parent;
+ lfs_entry_t entry;
+ int res = lfs_parent(lfs, oldpair, &parent, &entry);
+ if (res < 0) {
+ return res;
+ }
+
+ if (res) {
+ // update disk, this creates a desync
+ entry.d.u.dir[0] = newpair[0];
+ entry.d.u.dir[1] = newpair[1];
+
+ int err = lfs_dir_update(lfs, &parent, &entry, NULL);
+ if (err) {
+ return err;
+ }
+
+ // update internal root
+ if (lfs_paircmp(oldpair, lfs->root) == 0) {
+ LFS_DEBUG("Relocating root %" PRIu32 " %" PRIu32,
+ newpair[0], newpair[1]);
+ lfs->root[0] = newpair[0];
+ lfs->root[1] = newpair[1];
+ }
+
+ // clean up bad block, which should now be a desync
+ return lfs_deorphan(lfs);
+ }
+
+ // find pred
+ res = lfs_pred(lfs, oldpair, &parent);
+ if (res < 0) {
+ return res;
+ }
+
+ if (res) {
+ // just replace bad pair, no desync can occur
+ parent.d.tail[0] = newpair[0];
+ parent.d.tail[1] = newpair[1];
+
+ return lfs_dir_commit(lfs, &parent, NULL, 0);
+ }
+
+ // couldn't find dir, must be new
+ return 0;
+}
+
+int lfs_deorphan(lfs_t *lfs) {
+ lfs->deorphaned = true;
+
+ if (lfs_pairisnull(lfs->root)) {
+ return 0;
+ }
+
+ lfs_dir_t pdir = {.d.size = 0x80000000};
+ lfs_dir_t cwd = {.d.tail[0] = 0, .d.tail[1] = 1};
+
+ // iterate over all directory directory entries
+ while (!lfs_pairisnull(cwd.d.tail)) {
+ int err = lfs_dir_fetch(lfs, &cwd, cwd.d.tail);
+ if (err) {
+ return err;
+ }
+
+ // check head blocks for orphans
+ if (!(0x80000000 & pdir.d.size)) {
+ // check if we have a parent
+ lfs_dir_t parent;
+ lfs_entry_t entry;
+ int res = lfs_parent(lfs, pdir.d.tail, &parent, &entry);
+ if (res < 0) {
+ return res;
+ }
+
+ if (!res) {
+ // we are an orphan
+ LFS_DEBUG("Found orphan %" PRIu32 " %" PRIu32,
+ pdir.d.tail[0], pdir.d.tail[1]);
+
+ pdir.d.tail[0] = cwd.d.tail[0];
+ pdir.d.tail[1] = cwd.d.tail[1];
+
+ err = lfs_dir_commit(lfs, &pdir, NULL, 0);
+ if (err) {
+ return err;
+ }
+
+ break;
+ }
+
+ if (!lfs_pairsync(entry.d.u.dir, pdir.d.tail)) {
+ // we have desynced
+ LFS_DEBUG("Found desync %" PRIu32 " %" PRIu32,
+ entry.d.u.dir[0], entry.d.u.dir[1]);
+
+ pdir.d.tail[0] = entry.d.u.dir[0];
+ pdir.d.tail[1] = entry.d.u.dir[1];
+
+ err = lfs_dir_commit(lfs, &pdir, NULL, 0);
+ if (err) {
+ return err;
+ }
+
+ break;
+ }
+ }
+
+ // check entries for moves
+ lfs_entry_t entry;
+ while (true) {
+ err = lfs_dir_next(lfs, &cwd, &entry);
+ if (err && err != LFS_ERR_NOENT) {
+ return err;
+ }
+
+ if (err == LFS_ERR_NOENT) {
+ break;
+ }
+
+ // found moved entry
+ if (entry.d.type & 0x80) {
+ int moved = lfs_moved(lfs, &entry.d.u);
+ if (moved < 0) {
+ return moved;
+ }
+
+ if (moved) {
+ LFS_DEBUG("Found move %" PRIu32 " %" PRIu32,
+ entry.d.u.dir[0], entry.d.u.dir[1]);
+ err = lfs_dir_remove(lfs, &cwd, &entry);
+ if (err) {
+ return err;
+ }
+ } else {
+ LFS_DEBUG("Found partial move %" PRIu32 " %" PRIu32,
+ entry.d.u.dir[0], entry.d.u.dir[1]);
+ entry.d.type &= ~0x80;
+ err = lfs_dir_update(lfs, &cwd, &entry, NULL);
+ if (err) {
+ return err;
+ }
+ }
+ }
+ }
+
+ memcpy(&pdir, &cwd, sizeof(pdir));
+ }
+
+ return 0;
+}
+
+static int lfs_statvfs_count(void *p, lfs_block_t b)
+{
+ *(lfs_size_t *)p += 1;
+ return 0;
+}
+
+int lfs_info(lfs_t *lfs, uint32_t *total, uint32_t *used)
+{
+ lfs_size_t in_use = 0;
+ int err = lfs_traverse(lfs, lfs_statvfs_count, &in_use);
+ if (err) {
+ LFS_ERROR("lfs_info got error %d", err);
+ return err;
+ }
+
+ if (total) {
+ *total = lfs->cfg->block_count * lfs->cfg->block_size;
+ }
+
+ if (used) {
+ *used = in_use * lfs->cfg->block_size;
+ }
+
+ return 0;
+}
diff --git a/libiot/lfs/lfs.h b/libiot/lfs/lfs.h
new file mode 100644
index 0000000..edc86d2
--- /dev/null
+++ b/libiot/lfs/lfs.h
@@ -0,0 +1,495 @@
+/*
+ * The little filesystem
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef LFS_H
+#define LFS_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+
+/// Version info ///
+
+// Software library version
+// Major (top-nibble), incremented on backwards incompatible changes
+// Minor (bottom-nibble), incremented on feature additions
+#define LFS_VERSION 0x00010006
+#define LFS_VERSION_MAJOR (0xffff & (LFS_VERSION >> 16))
+#define LFS_VERSION_MINOR (0xffff & (LFS_VERSION >> 0))
+
+// Version of On-disk data structures
+// Major (top-nibble), incremented on backwards incompatible changes
+// Minor (bottom-nibble), incremented on feature additions
+#define LFS_DISK_VERSION 0x00010001
+#define LFS_DISK_VERSION_MAJOR (0xffff & (LFS_DISK_VERSION >> 16))
+#define LFS_DISK_VERSION_MINOR (0xffff & (LFS_DISK_VERSION >> 0))
+
+
+/// Definitions ///
+
+// Type definitions
+typedef uint32_t lfs_size_t;
+typedef uint32_t lfs_off_t;
+
+typedef int32_t lfs_ssize_t;
+typedef int32_t lfs_soff_t;
+
+typedef uint32_t lfs_block_t;
+
+// Max name size in bytes
+#ifndef LFS_NAME_MAX
+#define LFS_NAME_MAX 255
+#endif
+
+// Possible error codes, these are negative to allow
+// valid positive return values
+enum lfs_error {
+ LFS_ERR_OK = 0, // No error
+ LFS_ERR_IO = -5, // Error during device operation
+ LFS_ERR_CORRUPT = -52, // Corrupted
+ LFS_ERR_NOENT = -2, // No directory entry
+ LFS_ERR_EXIST = -17, // Entry already exists
+ LFS_ERR_NOTDIR = -20, // Entry is not a dir
+ LFS_ERR_ISDIR = -21, // Entry is a dir
+ LFS_ERR_NOTEMPTY = -39, // Dir is not empty
+ LFS_ERR_BADF = -9, // Bad file number
+ LFS_ERR_INVAL = -22, // Invalid parameter
+ LFS_ERR_NOSPC = -28, // No space left on device
+ LFS_ERR_NOMEM = -12, // No more memory available
+};
+
+// File types
+enum lfs_type {
+ LFS_TYPE_REG = 0x11,
+ LFS_TYPE_DIR = 0x22,
+ LFS_TYPE_SUPERBLOCK = 0x2e,
+};
+
+// File open flags
+enum lfs_open_flags {
+ // open flags
+ LFS_O_RDONLY = 1, // Open a file as read only
+ LFS_O_WRONLY = 2, // Open a file as write only
+ LFS_O_RDWR = 3, // Open a file as read and write
+ LFS_O_CREAT = 0x0100, // Create a file if it does not exist
+ LFS_O_EXCL = 0x0200, // Fail if a file already exists
+ LFS_O_TRUNC = 0x0400, // Truncate the existing file to zero size
+ LFS_O_APPEND = 0x0800, // Move to end of file on every write
+
+ // internally used flags
+ LFS_F_DIRTY = 0x10000, // File does not match storage
+ LFS_F_WRITING = 0x20000, // File has been written since last flush
+ LFS_F_READING = 0x40000, // File has been read since last flush
+ LFS_F_ERRED = 0x80000, // An error occured during write
+};
+
+// File seek flags
+enum lfs_whence_flags {
+ LFS_SEEK_SET = 0, // Seek relative to an absolute position
+ LFS_SEEK_CUR = 1, // Seek relative to the current file position
+ LFS_SEEK_END = 2, // Seek relative to the end of the file
+};
+
+
+// Configuration provided during initialization of the littlefs
+struct lfs_config {
+ // Opaque user provided context that can be used to pass
+ // information to the block device operations
+ void *context;
+
+ // Read a region in a block. Negative error codes are propogated
+ // to the user.
+ int (*read)(const struct lfs_config *c, lfs_block_t block,
+ lfs_off_t off, void *buffer, lfs_size_t size);
+
+ // Program a region in a block. The block must have previously
+ // been erased. Negative error codes are propogated to the user.
+ // May return LFS_ERR_CORRUPT if the block should be considered bad.
+ int (*prog)(const struct lfs_config *c, lfs_block_t block,
+ lfs_off_t off, const void *buffer, lfs_size_t size);
+
+ // Erase a block. A block must be erased before being programmed.
+ // The state of an erased block is undefined. Negative error codes
+ // are propogated to the user.
+ // May return LFS_ERR_CORRUPT if the block should be considered bad.
+ int (*erase)(const struct lfs_config *c, lfs_block_t block);
+
+ // Sync the state of the underlying block device. Negative error codes
+ // are propogated to the user.
+ int (*sync)(const struct lfs_config *c);
+
+ // Minimum size of a block read. This determines the size of read buffers.
+ // This may be larger than the physical read size to improve performance
+ // by caching more of the block device.
+ lfs_size_t read_size;
+
+ // Minimum size of a block program. This determines the size of program
+ // buffers. This may be larger than the physical program size to improve
+ // performance by caching more of the block device.
+ // Must be a multiple of the read size.
+ lfs_size_t prog_size;
+
+ // Size of an erasable block. This does not impact ram consumption and
+ // may be larger than the physical erase size. However, this should be
+ // kept small as each file currently takes up an entire block.
+ // Must be a multiple of the program size.
+ lfs_size_t block_size;
+
+ // Number of erasable blocks on the device.
+ lfs_size_t block_count;
+
+ // Number of blocks to lookahead during block allocation. A larger
+ // lookahead reduces the number of passes required to allocate a block.
+ // The lookahead buffer requires only 1 bit per block so it can be quite
+ // large with little ram impact. Should be a multiple of 32.
+ lfs_size_t lookahead;
+
+ // Optional, statically allocated read buffer. Must be read sized.
+ void *read_buffer;
+
+ // Optional, statically allocated program buffer. Must be program sized.
+ void *prog_buffer;
+
+ // Optional, statically allocated lookahead buffer. Must be 1 bit per
+ // lookahead block.
+ void *lookahead_buffer;
+
+ // Optional, statically allocated buffer for files. Must be program sized.
+ // If enabled, only one file may be opened at a time.
+ void *file_buffer;
+};
+
+// Optional configuration provided during lfs_file_opencfg
+struct lfs_file_config {
+ // Optional, statically allocated buffer for files. Must be program sized.
+ // If NULL, malloc will be used by default.
+ void *buffer;
+};
+
+// File info structure
+struct lfs_info {
+ // Type of the file, either LFS_TYPE_REG or LFS_TYPE_DIR
+ uint8_t type;
+
+ // Size of the file, only valid for REG files
+ lfs_size_t size;
+
+ // Name of the file stored as a null-terminated string
+ char name[LFS_NAME_MAX+1];
+};
+
+
+/// littlefs data structures ///
+typedef struct lfs_entry {
+ lfs_off_t off;
+
+ struct lfs_disk_entry {
+ uint8_t type;
+ uint8_t elen;
+ uint8_t alen;
+ uint8_t nlen;
+ union {
+ struct {
+ lfs_block_t head;
+ lfs_size_t size;
+ } file;
+ lfs_block_t dir[2];
+ } u;
+ } d;
+} lfs_entry_t;
+
+typedef struct lfs_cache {
+ lfs_block_t block;
+ lfs_off_t off;
+ uint8_t *buffer;
+} lfs_cache_t;
+
+typedef struct lfs_file {
+ struct lfs_file *next;
+ lfs_block_t pair[2];
+ lfs_off_t poff;
+
+ lfs_block_t head;
+ lfs_size_t size;
+
+ const struct lfs_file_config *cfg;
+ uint32_t flags;
+ lfs_off_t pos;
+ lfs_block_t block;
+ lfs_off_t off;
+ lfs_cache_t cache;
+} lfs_file_t;
+
+typedef struct lfs_dir {
+ struct lfs_dir *next;
+ lfs_block_t pair[2];
+ lfs_off_t off;
+
+ lfs_block_t head[2];
+ lfs_off_t pos;
+
+ struct lfs_disk_dir {
+ uint32_t rev;
+ lfs_size_t size;
+ lfs_block_t tail[2];
+ } d;
+} lfs_dir_t;
+
+typedef struct lfs_superblock {
+ lfs_off_t off;
+
+ struct lfs_disk_superblock {
+ uint8_t type;
+ uint8_t elen;
+ uint8_t alen;
+ uint8_t nlen;
+ lfs_block_t root[2];
+ uint32_t block_size;
+ uint32_t block_count;
+ uint32_t version;
+ char magic[8];
+ } d;
+} lfs_superblock_t;
+
+typedef struct lfs_free {
+ lfs_block_t off;
+ lfs_block_t size;
+ lfs_block_t i;
+ lfs_block_t ack;
+ uint32_t *buffer;
+} lfs_free_t;
+
+// The littlefs type
+typedef struct lfs {
+ const struct lfs_config *cfg;
+
+ lfs_block_t root[2];
+ lfs_file_t *files;
+ lfs_dir_t *dirs;
+
+ lfs_cache_t rcache;
+ lfs_cache_t pcache;
+
+ lfs_free_t free;
+ bool deorphaned;
+} lfs_t;
+
+
+/// Filesystem functions ///
+
+// Format a block device with the littlefs
+//
+// Requires a littlefs object and config struct. This clobbers the littlefs
+// object, and does not leave the filesystem mounted. The config struct must
+// be zeroed for defaults and backwards compatibility.
+//
+// Returns a negative error code on failure.
+int lfs_format(lfs_t *lfs, const struct lfs_config *config);
+
+// Mounts a littlefs
+//
+// Requires a littlefs object and config struct. Multiple filesystems
+// may be mounted simultaneously with multiple littlefs objects. Both
+// lfs and config must be allocated while mounted. The config struct must
+// be zeroed for defaults and backwards compatibility.
+//
+// Returns a negative error code on failure.
+int lfs_mount(lfs_t *lfs, const struct lfs_config *config);
+
+// Unmounts a littlefs
+//
+// Does nothing besides releasing any allocated resources.
+// Returns a negative error code on failure.
+int lfs_umount(lfs_t *lfs);
+
+/// General operations ///
+
+// Removes a file or directory
+//
+// If removing a directory, the directory must be empty.
+// Returns a negative error code on failure.
+int lfs_remove(lfs_t *lfs, const char *path);
+
+// Rename or move a file or directory
+//
+// If the destination exists, it must match the source in type.
+// If the destination is a directory, the directory must be empty.
+//
+// Returns a negative error code on failure.
+int lfs_rename(lfs_t *lfs, const char *oldpath, const char *newpath);
+
+// Find info about a file or directory
+//
+// Fills out the info structure, based on the specified file or directory.
+// Returns a negative error code on failure.
+int lfs_stat(lfs_t *lfs, const char *path, struct lfs_info *info);
+
+
+/// File operations ///
+
+// Open a file
+//
+// The mode that the file is opened in is determined by the flags, which
+// are values from the enum lfs_open_flags that are bitwise-ored together.
+//
+// Returns a negative error code on failure.
+int lfs_file_open(lfs_t *lfs, lfs_file_t *file,
+ const char *path, int flags);
+
+// Open a file with extra configuration
+//
+// The mode that the file is opened in is determined by the flags, which
+// are values from the enum lfs_open_flags that are bitwise-ored together.
+//
+// The config struct provides additional config options per file as described
+// above. The config struct must be allocated while the file is open, and the
+// config struct must be zeroed for defaults and backwards compatibility.
+//
+// Returns a negative error code on failure.
+int lfs_file_opencfg(lfs_t *lfs, lfs_file_t *file,
+ const char *path, int flags,
+ const struct lfs_file_config *config);
+
+// Close a file
+//
+// Any pending writes are written out to storage as though
+// sync had been called and releases any allocated resources.
+//
+// Returns a negative error code on failure.
+int lfs_file_close(lfs_t *lfs, lfs_file_t *file);
+
+// Synchronize a file on storage
+//
+// Any pending writes are written out to storage.
+// Returns a negative error code on failure.
+int lfs_file_sync(lfs_t *lfs, lfs_file_t *file);
+
+// Read data from file
+//
+// Takes a buffer and size indicating where to store the read data.
+// Returns the number of bytes read, or a negative error code on failure.
+lfs_ssize_t lfs_file_read(lfs_t *lfs, lfs_file_t *file,
+ void *buffer, lfs_size_t size);
+
+// Write data to file
+//
+// Takes a buffer and size indicating the data to write. The file will not
+// actually be updated on the storage until either sync or close is called.
+//
+// Returns the number of bytes written, or a negative error code on failure.
+lfs_ssize_t lfs_file_write(lfs_t *lfs, lfs_file_t *file,
+ const void *buffer, lfs_size_t size);
+
+// Change the position of the file
+//
+// The change in position is determined by the offset and whence flag.
+// Returns the old position of the file, or a negative error code on failure.
+lfs_soff_t lfs_file_seek(lfs_t *lfs, lfs_file_t *file,
+ lfs_soff_t off, int whence);
+
+// Truncates the size of the file to the specified size
+//
+// Returns a negative error code on failure.
+int lfs_file_truncate(lfs_t *lfs, lfs_file_t *file, lfs_off_t size);
+
+// Return the position of the file
+//
+// Equivalent to lfs_file_seek(lfs, file, 0, LFS_SEEK_CUR)
+// Returns the position of the file, or a negative error code on failure.
+lfs_soff_t lfs_file_tell(lfs_t *lfs, lfs_file_t *file);
+
+// Change the position of the file to the beginning of the file
+//
+// Equivalent to lfs_file_seek(lfs, file, 0, LFS_SEEK_CUR)
+// Returns a negative error code on failure.
+int lfs_file_rewind(lfs_t *lfs, lfs_file_t *file);
+
+// Return the size of the file
+//
+// Similar to lfs_file_seek(lfs, file, 0, LFS_SEEK_END)
+// Returns the size of the file, or a negative error code on failure.
+lfs_soff_t lfs_file_size(lfs_t *lfs, lfs_file_t *file);
+
+
+/// Directory operations ///
+
+// Create a directory
+//
+// Returns a negative error code on failure.
+int lfs_mkdir(lfs_t *lfs, const char *path);
+
+// Open a directory
+//
+// Once open a directory can be used with read to iterate over files.
+// Returns a negative error code on failure.
+int lfs_dir_open(lfs_t *lfs, lfs_dir_t *dir, const char *path);
+
+// Close a directory
+//
+// Releases any allocated resources.
+// Returns a negative error code on failure.
+int lfs_dir_close(lfs_t *lfs, lfs_dir_t *dir);
+
+// Read an entry in the directory
+//
+// Fills out the info structure, based on the specified file or directory.
+// Returns a negative error code on failure.
+int lfs_dir_read(lfs_t *lfs, lfs_dir_t *dir, struct lfs_info *info);
+
+// Change the position of the directory
+//
+// The new off must be a value previous returned from tell and specifies
+// an absolute offset in the directory seek.
+//
+// Returns a negative error code on failure.
+int lfs_dir_seek(lfs_t *lfs, lfs_dir_t *dir, lfs_off_t off);
+
+// Return the position of the directory
+//
+// The returned offset is only meant to be consumed by seek and may not make
+// sense, but does indicate the current position in the directory iteration.
+//
+// Returns the position of the directory, or a negative error code on failure.
+lfs_soff_t lfs_dir_tell(lfs_t *lfs, lfs_dir_t *dir);
+
+// Change the position of the directory to the beginning of the directory
+//
+// Returns a negative error code on failure.
+int lfs_dir_rewind(lfs_t *lfs, lfs_dir_t *dir);
+
+
+/// Miscellaneous littlefs specific operations ///
+
+// Traverse through all blocks in use by the filesystem
+//
+// The provided callback will be called with each block address that is
+// currently in use by the filesystem. This can be used to determine which
+// blocks are in use or how much of the storage is available.
+//
+// Returns a negative error code on failure.
+int lfs_traverse(lfs_t *lfs, int (*cb)(void*, lfs_block_t), void *data);
+
+// Prunes any recoverable errors that may have occured in the filesystem
+//
+// Not needed to be called by user unless an operation is interrupted
+// but the filesystem is still mounted. This is already called on first
+// allocation.
+//
+// Returns a negative error code on failure.
+int lfs_deorphan(lfs_t *lfs);
+
+int lfs_info(lfs_t *lfs, uint32_t *total, uint32_t *used);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif
diff --git a/libiot/lfs/lfs_util.c b/libiot/lfs/lfs_util.c
new file mode 100644
index 0000000..9ca0756
--- /dev/null
+++ b/libiot/lfs/lfs_util.c
@@ -0,0 +1,31 @@
+/*
+ * lfs util functions
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#include "lfs_util.h"
+
+// Only compile if user does not provide custom config
+#ifndef LFS_CONFIG
+
+
+// Software CRC implementation with small lookup table
+void lfs_crc(uint32_t *restrict crc, const void *buffer, size_t size) {
+ static const uint32_t rtable[16] = {
+ 0x00000000, 0x1db71064, 0x3b6e20c8, 0x26d930ac,
+ 0x76dc4190, 0x6b6b51f4, 0x4db26158, 0x5005713c,
+ 0xedb88320, 0xf00f9344, 0xd6d6a3e8, 0xcb61b38c,
+ 0x9b64c2b0, 0x86d3d2d4, 0xa00ae278, 0xbdbdf21c,
+ };
+
+ const uint8_t *data = buffer;
+
+ for (size_t i = 0; i < size; i++) {
+ *crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 0)) & 0xf];
+ *crc = (*crc >> 4) ^ rtable[(*crc ^ (data[i] >> 4)) & 0xf];
+ }
+}
+
+
+#endif
diff --git a/libiot/lfs/lfs_util.h b/libiot/lfs/lfs_util.h
new file mode 100644
index 0000000..b2dc237
--- /dev/null
+++ b/libiot/lfs/lfs_util.h
@@ -0,0 +1,186 @@
+/*
+ * lfs utility functions
+ *
+ * Copyright (c) 2017, Arm Limited. All rights reserved.
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+#ifndef LFS_UTIL_H
+#define LFS_UTIL_H
+
+// Users can override lfs_util.h with their own configuration by defining
+// LFS_CONFIG as a header file to include (-DLFS_CONFIG=lfs_config.h).
+//
+// If LFS_CONFIG is used, none of the default utils will be emitted and must be
+// provided by the config file. To start I would suggest copying lfs_util.h and
+// modifying as needed.
+#ifdef LFS_CONFIG
+#define LFS_STRINGIZE(x) LFS_STRINGIZE2(x)
+#define LFS_STRINGIZE2(x) #x
+#include LFS_STRINGIZE(LFS_CONFIG)
+#else
+
+// System includes
+#include <stdint.h>
+#include <stdbool.h>
+#include <string.h>
+
+#ifndef LFS_NO_MALLOC
+#include <stdlib.h>
+#endif
+#ifndef LFS_NO_ASSERT
+#include <assert.h>
+#endif
+#if !defined(LFS_NO_DEBUG) || !defined(LFS_NO_WARN) || !defined(LFS_NO_ERROR)
+#include <stdio.h>
+#endif
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif
+
+
+// Macros, may be replaced by system specific wrappers. Arguments to these
+// macros must not have side-effects as the macros can be removed for a smaller
+// code footprint
+
+// Logging functions
+#ifndef LFS_NO_DEBUG
+#define LFS_DEBUG(fmt, ...) \
+ printf("lfs debug:%d: " fmt "\n", __LINE__, __VA_ARGS__)
+#else
+#define LFS_DEBUG(fmt, ...)
+#endif
+
+#ifndef LFS_NO_WARN
+#define LFS_WARN(fmt, ...) \
+ printf("lfs warn:%d: " fmt "\n", __LINE__, __VA_ARGS__)
+#else
+#define LFS_WARN(fmt, ...)
+#endif
+
+#ifndef LFS_NO_ERROR
+#define LFS_ERROR(fmt, ...) \
+ printf("lfs error:%d: " fmt "\n", __LINE__, __VA_ARGS__)
+#else
+#define LFS_ERROR(fmt, ...)
+#endif
+
+// Runtime assertions
+#ifndef LFS_NO_ASSERT
+#define LFS_ASSERT(test) assert(test)
+#else
+#define LFS_ASSERT(test)
+#endif
+
+
+// Builtin functions, these may be replaced by more efficient
+// toolchain-specific implementations. LFS_NO_INTRINSICS falls back to a more
+// expensive basic C implementation for debugging purposes
+
+// Min/max functions for unsigned 32-bit numbers
+static inline uint32_t lfs_max(uint32_t a, uint32_t b) {
+ return (a > b) ? a : b;
+}
+
+static inline uint32_t lfs_min(uint32_t a, uint32_t b) {
+ return (a < b) ? a : b;
+}
+
+// Find the next smallest power of 2 less than or equal to a
+static inline uint32_t lfs_npw2(uint32_t a) {
+#if !defined(LFS_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
+ return 32 - __builtin_clz(a-1);
+#else
+ uint32_t r = 0;
+ uint32_t s;
+ a -= 1;
+ s = (a > 0xffff) << 4; a >>= s; r |= s;
+ s = (a > 0xff ) << 3; a >>= s; r |= s;
+ s = (a > 0xf ) << 2; a >>= s; r |= s;
+ s = (a > 0x3 ) << 1; a >>= s; r |= s;
+ return (r | (a >> 1)) + 1;
+#endif
+}
+
+// Count the number of trailing binary zeros in a
+// lfs_ctz(0) may be undefined
+static inline uint32_t lfs_ctz(uint32_t a) {
+#if !defined(LFS_NO_INTRINSICS) && defined(__GNUC__)
+ return __builtin_ctz(a);
+#else
+ return lfs_npw2((a & -a) + 1) - 1;
+#endif
+}
+
+// Count the number of binary ones in a
+static inline uint32_t lfs_popc(uint32_t a) {
+#if !defined(LFS_NO_INTRINSICS) && (defined(__GNUC__) || defined(__CC_ARM))
+ return __builtin_popcount(a);
+#else
+ a = a - ((a >> 1) & 0x55555555);
+ a = (a & 0x33333333) + ((a >> 2) & 0x33333333);
+ return (((a + (a >> 4)) & 0xf0f0f0f) * 0x1010101) >> 24;
+#endif
+}
+
+// Find the sequence comparison of a and b, this is the distance
+// between a and b ignoring overflow
+static inline int lfs_scmp(uint32_t a, uint32_t b) {
+ return (int)(unsigned)(a - b);
+}
+
+// Convert from 32-bit little-endian to native order
+static inline uint32_t lfs_fromle32(uint32_t a) {
+#if !defined(LFS_NO_INTRINSICS) && ( \
+ (defined( BYTE_ORDER ) && BYTE_ORDER == ORDER_LITTLE_ENDIAN ) || \
+ (defined(__BYTE_ORDER ) && __BYTE_ORDER == __ORDER_LITTLE_ENDIAN ) || \
+ (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__))
+ return a;
+#elif !defined(LFS_NO_INTRINSICS) && ( \
+ (defined( BYTE_ORDER ) && BYTE_ORDER == ORDER_BIG_ENDIAN ) || \
+ (defined(__BYTE_ORDER ) && __BYTE_ORDER == __ORDER_BIG_ENDIAN ) || \
+ (defined(__BYTE_ORDER__) && __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__))
+ return __builtin_bswap32(a);
+#else
+ return (((uint8_t*)&a)[0] << 0) |
+ (((uint8_t*)&a)[1] << 8) |
+ (((uint8_t*)&a)[2] << 16) |
+ (((uint8_t*)&a)[3] << 24);
+#endif
+}
+
+// Convert to 32-bit little-endian from native order
+static inline uint32_t lfs_tole32(uint32_t a) {
+ return lfs_fromle32(a);
+}
+
+// Calculate CRC-32 with polynomial = 0x04c11db7
+void lfs_crc(uint32_t *crc, const void *buffer, size_t size);
+
+// Allocate memory, only used if buffers are not provided to littlefs
+static inline void *lfs_malloc(size_t size) {
+#ifndef LFS_NO_MALLOC
+ return malloc(size);
+#else
+ (void)size;
+ return NULL;
+#endif
+}
+
+// Deallocate memory, only used if buffers are not provided to littlefs
+static inline void lfs_free(void *p) {
+#ifndef LFS_NO_MALLOC
+ free(p);
+#else
+ (void)p;
+#endif
+}
+
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif
+#endif
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