static int fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
struct iterator* it)
{
/* move iterator to the next entry in the directory */
it->offset += sizeof(struct exfat_entry);
/* fetch the next cluster if needed */
if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
{
/* reached the end of directory; the caller should check this
condition too */
if (it->offset >= parent->size)
return 0;
it->cluster = exfat_next_cluster(ef, parent, it->cluster);
if (CLUSTER_INVALID(it->cluster))
{
exfat_error("invalid cluster 0x%x while reading directory",
it->cluster);
return 1;
}
if (exfat_pread(ef->dev, it->chunk, CLUSTER_SIZE(*ef->sb),
exfat_c2o(ef, it->cluster)) < 0)
{
exfat_error("failed to read the next directory cluster %#x",
it->cluster);
return 1;
}
}
return 0;
}
static int fuse_exfat_statfs(const char* path, struct statvfs* sfs)
{
exfat_debug("[%s]", __func__);
sfs->f_bsize = CLUSTER_SIZE(*ef.sb);
sfs->f_frsize = CLUSTER_SIZE(*ef.sb);
sfs->f_blocks = le64_to_cpu(ef.sb->sector_count) >> ef.sb->spc_bits;
sfs->f_bavail = exfat_count_free_clusters(&ef);
sfs->f_bfree = sfs->f_bavail;
sfs->f_namemax = EXFAT_NAME_MAX;
/*
Below are fake values because in exFAT there is
a) no simple way to count files;
b) no such thing as inode;
So here we assume that inode = cluster.
*/
sfs->f_files = le32_to_cpu(ef.sb->cluster_count);
sfs->f_favail = sfs->f_bfree >> ef.sb->spc_bits;
sfs->f_ffree = sfs->f_bavail;
#if defined(__AROS__) || defined(AMIGA)
/* flags */
sfs->f_flag = 0;
if (ef.ro)
sfs->f_flag |= ST_RDONLY;
#endif
return 0;
}
static int erase_range(struct exfat* ef, struct exfat_node* node,
uint64_t begin, uint64_t end)
{
uint64_t cluster_boundary;
cluster_t cluster;
if (begin >= end)
return 0;
cluster_boundary = (begin | (CLUSTER_SIZE(*ef->sb) - 1)) + 1;
cluster = exfat_advance_cluster(ef, node,
begin / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(cluster))
{
exfat_error("invalid cluster 0x%x while erasing", cluster);
return -EIO;
}
/* erase from the beginning to the closest cluster boundary */
erase_raw(ef, MIN(cluster_boundary, end) - begin,
exfat_c2o(ef, cluster) + begin % CLUSTER_SIZE(*ef->sb));
/* erase whole clusters */
while (cluster_boundary < end)
{
cluster = exfat_next_cluster(ef, node, cluster);
/* the cluster cannot be invalid because we have just allocated it */
if (CLUSTER_INVALID(cluster))
exfat_bug("invalid cluster 0x%x after allocation", cluster);
erase_raw(ef, CLUSTER_SIZE(*ef->sb), exfat_c2o(ef, cluster));
cluster_boundary += CLUSTER_SIZE(*ef->sb);
}
return 0;
}
static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
off64_t deleted_offset)
{
const struct exfat_node* node;
const struct exfat_node* last_node;
uint64_t entries = 1; /* a directory always has at leat 1 entry (EOD) */
uint64_t new_size;
struct exfat_entry eod;
off64_t eod_offset;
int rc;
if (!(dir->flags & EXFAT_ATTRIB_DIR))
exfat_bug("attempted to shrink a file");
if (!(dir->flags & EXFAT_ATTRIB_CACHED))
exfat_bug("attempted to shrink uncached directory");
for (last_node = node = dir->child; node; node = node->next)
{
if (deleted_offset < node->entry_offset)
{
/* there are other entries after the removed one, no way to shrink
this directory */
return 0;
}
if (last_node->entry_offset < node->entry_offset)
last_node = node;
}
if (last_node)
{
/* offset of the last entry */
entries += last_node->entry_offset / sizeof(struct exfat_entry);
/* two subentries with meta info */
entries += 2;
/* subentries with file name */
entries += DIV_ROUND_UP(utf16_length(last_node->name),
EXFAT_ENAME_MAX);
}
new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
if (new_size == dir->size)
return 0;
rc = exfat_truncate(ef, dir, new_size);
if (rc != 0)
return rc;
/* put EOD entry at the end of the last cluster */
memset(&eod, 0, sizeof(eod));
eod_offset = new_size - sizeof(struct exfat_entry);
if (last_node)
exfat_write_raw(&eod, sizeof(eod),
co2o(ef, last_node->entry_cluster, eod_offset), ef->fd);
else
exfat_write_raw(&eod, sizeof(eod),
co2o(ef, dir->start_cluster, eod_offset), ef->fd);
return 0;
}
static int shrink_directory(struct exfat* ef, struct exfat_node* dir,
off64_t deleted_offset)
{
const struct exfat_node* node;
const struct exfat_node* last_node;
uint64_t entries = 0;
uint64_t new_size;
int rc;
if (!(dir->flags & EXFAT_ATTRIB_DIR))
exfat_bug("attempted to shrink a file");
if (!(dir->flags & EXFAT_ATTRIB_CACHED))
exfat_bug("attempted to shrink uncached directory");
for (last_node = node = dir->child; node; node = node->next)
{
if (deleted_offset < node->entry_offset)
{
/* there are other entries after the removed one, no way to shrink
this directory */
return 0;
}
if (last_node->entry_offset < node->entry_offset)
last_node = node;
}
if (last_node)
{
/* offset of the last entry */
entries += last_node->entry_offset / sizeof(struct exfat_entry);
/* two subentries with meta info */
entries += 2;
/* subentries with file name */
entries += DIV_ROUND_UP(utf16_length(last_node->name),
EXFAT_ENAME_MAX);
}
new_size = DIV_ROUND_UP(entries * sizeof(struct exfat_entry),
CLUSTER_SIZE(*ef->sb)) * CLUSTER_SIZE(*ef->sb);
if (new_size == 0) /* directory always has at least 1 cluster */
new_size = CLUSTER_SIZE(*ef->sb);
if (new_size == dir->size)
return 0;
rc = exfat_truncate(ef, dir, new_size, true);
if (rc != 0)
return rc;
return 0;
}
ssize_t exfat_generic_pwrite(struct exfat* ef, struct exfat_node* node,
const void* buffer, size_t size, off64_t offset)
{
cluster_t cluster;
const char* bufp = buffer;
off64_t lsize, loffset, remainder;
if (offset > node->size)
if (exfat_truncate(ef, node, offset, true) != 0)
return -1;
if (offset + size > node->size)
if (exfat_truncate(ef, node, offset + size, false) != 0)
return -1;
if (size == 0)
return 0;
cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(cluster))
{
exfat_error("invalid cluster 0x%x while writing", cluster);
return -1;
}
loffset = offset % CLUSTER_SIZE(*ef->sb);
remainder = size;
while (remainder > 0)
{
if (CLUSTER_INVALID(cluster))
{
exfat_error("invalid cluster 0x%x while writing", cluster);
return -1;
}
lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
if (exfat_pwrite(ef->dev, bufp, lsize,
exfat_c2o(ef, cluster) + loffset) < 0)
{
exfat_error("failed to write cluster %#x", cluster);
ef->was_dirty = true; // Leaves the volume "mounted", to force chkdsk on it.
return -1;
}
bufp += lsize;
loffset = 0;
remainder -= lsize;
cluster = exfat_next_cluster(ef, node, cluster);
}
exfat_update_mtime(node);
return size - remainder;
}
static struct exfat_entry_label *find_label(blkid_probe pr,
const struct exfat_super_block *sb)
{
uint32_t cluster = le32_to_cpu(sb->rootdir_cluster);
uint64_t offset = cluster_to_offset(sb, cluster);
uint8_t *entry;
const size_t max_iter = 10000;
size_t i = 0;
for (; i < max_iter; i++) {
entry = (uint8_t *) blkid_probe_get_buffer(pr, offset,
EXFAT_ENTRY_SIZE);
if (!entry)
return NULL;
if (entry[0] == EXFAT_ENTRY_EOD)
return NULL;
if (entry[0] == EXFAT_ENTRY_LABEL)
return (struct exfat_entry_label *) entry;
offset += EXFAT_ENTRY_SIZE;
if (offset % CLUSTER_SIZE(sb) == 0) {
cluster = next_cluster(pr, sb, cluster);
if (cluster < EXFAT_FIRST_DATA_CLUSTER)
return NULL;
if (cluster > EXFAT_LAST_DATA_CLUSTER)
return NULL;
offset = cluster_to_offset(sb, cluster);
}
}
return NULL;
}
static int probe_exfat(blkid_probe pr, const struct blkid_idmag *mag)
{
struct exfat_super_block *sb;
struct exfat_entry_label *label;
sb = blkid_probe_get_sb(pr, mag, struct exfat_super_block);
if (!sb || !CLUSTER_SIZE(sb))
return errno ? -errno : BLKID_PROBE_NONE;
label = find_label(pr, sb);
if (label)
blkid_probe_set_utf8label(pr, label->name,
min(label->length * 2, 30), BLKID_ENC_UTF16LE);
else if (errno)
return -errno;
blkid_probe_sprintf_uuid(pr, sb->volume_serial, 4,
"%02hhX%02hhX-%02hhX%02hhX",
sb->volume_serial[3], sb->volume_serial[2],
sb->volume_serial[1], sb->volume_serial[0]);
blkid_probe_sprintf_version(pr, "%u.%u",
sb->version.vermaj, sb->version.vermin);
return BLKID_PROBE_OK;
}
static uint64_t rootdir_size(const struct exfat* ef)
{
uint32_t clusters = 0;
uint32_t clusters_max = le32_to_cpu(ef->sb->cluster_count);
cluster_t rootdir_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
/* Iterate all clusters of the root directory to calculate its size.
It can't be contiguous because there is no flag to indicate this. */
do
{
if (clusters == clusters_max) /* infinite loop detected */
{
exfat_error("root directory cannot occupy all %d clusters",
clusters);
return 0;
}
if (CLUSTER_INVALID(rootdir_cluster))
{
exfat_error("bad cluster %#x while reading root directory",
rootdir_cluster);
return 0;
}
rootdir_cluster = exfat_next_cluster(ef, ef->root, rootdir_cluster);
clusters++;
}
while (rootdir_cluster != EXFAT_CLUSTER_END);
return (uint64_t) clusters * CLUSTER_SIZE(*ef->sb);
}
static int nodeck(struct exfat* ef, struct exfat_node* node)
{
const cluster_t cluster_size = CLUSTER_SIZE(*ef->sb);
cluster_t clusters = (node->size + cluster_size - 1) / cluster_size;
cluster_t c = node->start_cluster;
int rc = 0;
while (clusters--)
{
if (CLUSTER_INVALID(c))
{
char name[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
exfat_get_name(node, name, sizeof(name) - 1);
exfat_error("file '%s' has invalid cluster 0x%x", name, c);
rc = 1;
break;
}
if (BMAP_GET(ef->cmap.chunk, c - EXFAT_FIRST_DATA_CLUSTER) == 0)
{
char name[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
exfat_get_name(node, name, sizeof(name) - 1);
exfat_error("cluster 0x%x of file '%s' is not allocated", c, name);
rc = 1;
}
c = exfat_next_cluster(ef, node, c);
}
return rc;
}
static void next_entry(struct exfat* ef, const struct exfat_node* parent,
cluster_t* cluster, off64_t* offset)
{
*offset += sizeof(struct exfat_entry);
if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
/* next cluster cannot be invalid */
*cluster = exfat_next_cluster(ef, parent, *cluster);
}
static int opendir(struct exfat* ef, const struct exfat_node* dir,
struct iterator* it)
{
if (!(dir->flags & EXFAT_ATTRIB_DIR))
exfat_bug("not a directory");
it->cluster = dir->start_cluster;
it->offset = 0;
it->contiguous = IS_CONTIGUOUS(*dir);
it->chunk = malloc(CLUSTER_SIZE(*ef->sb));
if (it->chunk == NULL)
{
exfat_error("out of memory");
return -ENOMEM;
}
exfat_read_raw(it->chunk, CLUSTER_SIZE(*ef->sb),
exfat_c2o(ef, it->cluster), ef->fd);
return 0;
}
ssize_t exfat_generic_pread(const struct exfat* ef, struct exfat_node* node,
void* buffer, size_t size, off64_t offset)
{
cluster_t cluster;
char* bufp = buffer;
off64_t lsize, loffset, remainder;
if (offset >= node->size)
return 0;
if (size == 0)
return 0;
cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(cluster))
{
exfat_error("invalid cluster 0x%x while reading", cluster);
return -1;
}
loffset = offset % CLUSTER_SIZE(*ef->sb);
remainder = MIN(size, node->size - offset);
while (remainder > 0)
{
if (CLUSTER_INVALID(cluster))
{
exfat_error("invalid cluster 0x%x while reading", cluster);
return -1;
}
lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
if (exfat_pread(ef->dev, bufp, lsize,
exfat_c2o(ef, cluster) + loffset) < 0)
{
exfat_error("failed to read cluster %#x", cluster);
return -1;
}
bufp += lsize;
loffset = 0;
remainder -= lsize;
cluster = exfat_next_cluster(ef, node, cluster);
}
if (!ef->ro && !ef->noatime)
exfat_update_atime(node);
return MIN(size, node->size - offset) - remainder;
}
static int fetch_next_entry(struct exfat* ef, const struct exfat_node* parent,
struct iterator* it)
{
/* move iterator to the next entry in the directory */
it->offset += sizeof(struct exfat_entry);
/* fetch the next cluster if needed */
if ((it->offset & (CLUSTER_SIZE(*ef->sb) - 1)) == 0)
{
it->cluster = exfat_next_cluster(ef, parent, it->cluster);
if (CLUSTER_INVALID(it->cluster))
{
exfat_error("invalid cluster while reading directory");
return 1;
}
exfat_read_raw(it->chunk, CLUSTER_SIZE(*ef->sb),
exfat_c2o(ef, it->cluster), ef->fd);
}
return 0;
}
ssize_t exfat_write(struct exfat* ef, struct exfat_node* node,
const void* buffer, size_t size, off_t offset)
{
cluster_t cluster;
const char* bufp = buffer;
off_t lsize, loffset, remainder;
if (offset + size > node->size)
{
int rc = exfat_truncate(ef, node, offset + size);
if (rc != 0)
return rc;
}
if (size == 0)
return 0;
cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(cluster))
{
exfat_error("got invalid cluster");
return -1;
}
loffset = offset % CLUSTER_SIZE(*ef->sb);
remainder = size;
while (remainder > 0)
{
if (CLUSTER_INVALID(cluster))
{
exfat_error("got invalid cluster");
return -1;
}
lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
exfat_write_raw(bufp, lsize, exfat_c2o(ef, cluster) + loffset, ef->fd);
bufp += lsize;
loffset = 0;
remainder -= lsize;
cluster = exfat_next_cluster(ef, node, cluster);
}
exfat_update_mtime(node);
return size - remainder;
}
static void print_generic_info(const struct exfat_super_block* sb)
{
printf("Volume serial number 0x%08x\n",
le32_to_cpu(sb->volume_serial));
printf("FS version %hhu.%hhu\n",
sb->version.major, sb->version.minor);
printf("Sector size %10u\n",
SECTOR_SIZE(*sb));
printf("Cluster size %10u\n",
CLUSTER_SIZE(*sb));
}
ssize_t exfat_read(const struct exfat* ef, struct exfat_node* node,
void* buffer, size_t size, off_t offset)
{
cluster_t cluster;
char* bufp = buffer;
off_t lsize, loffset, remainder;
if (offset >= node->size)
return 0;
if (size == 0)
return 0;
cluster = exfat_advance_cluster(ef, node, offset / CLUSTER_SIZE(*ef->sb));
if (CLUSTER_INVALID(cluster))
{
exfat_error("got invalid cluster");
return -1;
}
loffset = offset % CLUSTER_SIZE(*ef->sb);
remainder = MIN(size, node->size - offset);
while (remainder > 0)
{
if (CLUSTER_INVALID(cluster))
{
exfat_error("got invalid cluster");
return -1;
}
lsize = MIN(CLUSTER_SIZE(*ef->sb) - loffset, remainder);
exfat_read_raw(bufp, lsize, exfat_c2o(ef, cluster) + loffset, ef->fd);
bufp += lsize;
loffset = 0;
remainder -= lsize;
cluster = exfat_next_cluster(ef, node, cluster);
}
if (!ef->ro && !ef->noatime)
exfat_update_atime(node);
return size - remainder;
}
static int fuse_exfat_statfs(const char* path, struct statvfs* sfs)
{
exfat_debug("[%s]", __func__);
sfs->f_bsize = CLUSTER_SIZE(*ef.sb);
sfs->f_frsize = CLUSTER_SIZE(*ef.sb);
sfs->f_blocks = le64_to_cpu(ef.sb->sector_count) >> ef.sb->spc_bits;
sfs->f_bavail = exfat_count_free_clusters(&ef);
sfs->f_bfree = sfs->f_bavail;
sfs->f_namemax = EXFAT_NAME_MAX;
/*
Below are fake values because in exFAT there is
a) no simple way to count files;
b) no such thing as inode;
So here we assume that inode = cluster.
*/
sfs->f_files = (sfs->f_blocks - sfs->f_bfree) >> ef.sb->spc_bits;
sfs->f_favail = sfs->f_bfree >> ef.sb->spc_bits;
sfs->f_ffree = sfs->f_bavail;
return 0;
}
static char* add_fuse_options(char* options, const char* spec)
{
options = add_option(options, "fsname", spec);
if (options == NULL)
return NULL;
options = add_user_option(options);
if (options == NULL)
return NULL;
options = add_blksize_option(options, CLUSTER_SIZE(*ef.sb));
if (options == NULL)
return NULL;
return options;
}
static bool next_entry(struct exfat* ef, const struct exfat_node* parent,
cluster_t* cluster, off_t* offset)
{
*offset += sizeof(struct exfat_entry);
if (*offset % CLUSTER_SIZE(*ef->sb) == 0)
{
*cluster = exfat_next_cluster(ef, parent, *cluster);
if (CLUSTER_INVALID(*cluster))
{
exfat_error("invalid cluster %#x while getting next entry",
*cluster);
return false;
}
}
return true;
}
int exfat_find_used_sectors(const struct exfat* ef, off_t* a, off_t* b)
{
cluster_t ca, cb;
if (*a == 0 && *b == 0)
ca = cb = EXFAT_FIRST_DATA_CLUSTER - 1;
else
{
ca = s2c(ef, *a);
cb = s2c(ef, *b);
}
if (find_used_clusters(ef, &ca, &cb) != 0)
return 1;
if (*a != 0 || *b != 0)
*a = c2s(ef, ca);
*b = c2s(ef, cb) + (CLUSTER_SIZE(*ef->sb) - 1) / SECTOR_SIZE(*ef->sb);
return 0;
}
int exfat_mount(struct exfat* ef, const char* spec, const char* options)
{
int rc;
enum exfat_mode mode;
exfat_tzset();
memset(ef, 0, sizeof(struct exfat));
parse_options(ef, options);
if (match_option(options, "ro"))
mode = EXFAT_MODE_RO;
else if (match_option(options, "ro_fallback"))
mode = EXFAT_MODE_ANY;
else
mode = EXFAT_MODE_RW;
ef->dev = exfat_open(spec, mode);
if (ef->dev == NULL)
return -EIO;
if (exfat_get_mode(ef->dev) == EXFAT_MODE_RO)
{
if (mode == EXFAT_MODE_ANY)
ef->ro = -1;
else
ef->ro = 1;
}
ef->sb = malloc(sizeof(struct exfat_super_block));
if (ef->sb == NULL)
{
exfat_close(ef->dev);
exfat_error("failed to allocate memory for the super block");
return -ENOMEM;
}
memset(ef->sb, 0, sizeof(struct exfat_super_block));
if (exfat_pread(ef->dev, ef->sb, sizeof(struct exfat_super_block), 0) < 0)
{
exfat_close(ef->dev);
free(ef->sb);
exfat_error("failed to read boot sector");
return -EIO;
}
if (memcmp(ef->sb->oem_name, "EXFAT ", 8) != 0)
{
exfat_close(ef->dev);
free(ef->sb);
exfat_error("exFAT file system is not found");
return -EIO;
}
/* sector cannot be smaller than 512 bytes */
if (ef->sb->sector_bits < 9)
{
exfat_close(ef->dev);
exfat_error("too small sector size: 2^%hhd", ef->sb->sector_bits);
free(ef->sb);
return -EIO;
}
/* officially exFAT supports cluster size up to 32 MB */
if ((int) ef->sb->sector_bits + (int) ef->sb->spc_bits > 25)
{
exfat_close(ef->dev);
exfat_error("too big cluster size: 2^(%hhd+%hhd)",
ef->sb->sector_bits, ef->sb->spc_bits);
free(ef->sb);
return -EIO;
}
ef->zero_cluster = malloc(CLUSTER_SIZE(*ef->sb));
if (ef->zero_cluster == NULL)
{
exfat_close(ef->dev);
free(ef->sb);
exfat_error("failed to allocate zero sector");
return -ENOMEM;
}
/* use zero_cluster as a temporary buffer for VBR checksum verification */
if (!verify_vbr_checksum(ef->dev, ef->zero_cluster, SECTOR_SIZE(*ef->sb)))
{
free(ef->zero_cluster);
exfat_close(ef->dev);
free(ef->sb);
return -EIO;
}
memset(ef->zero_cluster, 0, CLUSTER_SIZE(*ef->sb));
if (ef->sb->version.major != 1 || ef->sb->version.minor != 0)
{
free(ef->zero_cluster);
exfat_close(ef->dev);
exfat_error("unsupported exFAT version: %hhu.%hhu",
ef->sb->version.major, ef->sb->version.minor);
free(ef->sb);
return -EIO;
}
if (ef->sb->fat_count != 1)
{
free(ef->zero_cluster);
exfat_close(ef->dev);
exfat_error("unsupported FAT count: %hhu", ef->sb->fat_count);
free(ef->sb);
return -EIO;
}
if (le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb) >
exfat_get_size(ef->dev))
{
/* this can cause I/O errors later but we don't fail mounting to let
user rescue data */
exfat_warn("file system is larger than underlying device: "
"%"PRIu64" > %"PRIu64,
le64_to_cpu(ef->sb->sector_count) * SECTOR_SIZE(*ef->sb),
exfat_get_size(ef->dev));
}
ef->root = malloc(sizeof(struct exfat_node));
if (ef->root == NULL)
{
free(ef->zero_cluster);
exfat_close(ef->dev);
free(ef->sb);
exfat_error("failed to allocate root node");
return -ENOMEM;
}
memset(ef->root, 0, sizeof(struct exfat_node));
ef->root->flags = EXFAT_ATTRIB_DIR;
ef->root->start_cluster = le32_to_cpu(ef->sb->rootdir_cluster);
ef->root->fptr_cluster = ef->root->start_cluster;
ef->root->name[0] = cpu_to_le16('\0');
ef->root->size = rootdir_size(ef);
if (ef->root->size == 0)
{
free(ef->root);
free(ef->zero_cluster);
exfat_close(ef->dev);
free(ef->sb);
return -EIO;
}
/* exFAT does not have time attributes for the root directory */
ef->root->mtime = 0;
ef->root->atime = 0;
/* always keep at least 1 reference to the root node */
exfat_get_node(ef->root);
rc = exfat_cache_directory(ef, ef->root);
if (rc != 0)
goto error;
if (ef->upcase == NULL)
{
exfat_error("upcase table is not found");
goto error;
}
if (ef->cmap.chunk == NULL)
{
exfat_error("clusters bitmap is not found");
goto error;
}
if (prepare_super_block(ef) != 0)
goto error;
return 0;
error:
exfat_put_node(ef, ef->root);
exfat_reset_cache(ef);
free(ef->root);
free(ef->zero_cluster);
exfat_close(ef->dev);
free(ef->sb);
return -EIO;
}
/**
* Cluster + offset from the beginning of the directory to absolute offset.
*/
static off64_t co2o(struct exfat* ef, cluster_t cluster, off64_t offset)
{
return exfat_c2o(ef, cluster) + offset % CLUSTER_SIZE(*ef->sb);
}
/*
* Reads one entry in directory at position pointed by iterator and fills
* node structure.
*/
static int readdir(struct exfat* ef, const struct exfat_node* parent,
struct exfat_node** node, struct iterator* it)
{
int rc = -EIO;
const struct exfat_entry* entry;
const struct exfat_entry_meta1* meta1;
const struct exfat_entry_meta2* meta2;
const struct exfat_entry_name* file_name;
const struct exfat_entry_upcase* upcase;
const struct exfat_entry_bitmap* bitmap;
const struct exfat_entry_label* label;
uint8_t continuations = 0;
le16_t* namep = NULL;
uint16_t reference_checksum = 0;
uint16_t actual_checksum = 0;
uint64_t real_size = 0;
*node = NULL;
for (;;)
{
if (it->offset >= parent->size)
{
if (continuations != 0)
{
exfat_error("expected %hhu continuations", continuations);
goto error;
}
return -ENOENT; /* that's OK, means end of directory */
}
entry = get_entry_ptr(ef, it);
switch (entry->type)
{
case EXFAT_ENTRY_FILE:
if (continuations != 0)
{
exfat_error("expected %hhu continuations before new entry",
continuations);
goto error;
}
meta1 = (const struct exfat_entry_meta1*) entry;
continuations = meta1->continuations;
/* each file entry must have at least 2 continuations:
info and name */
if (continuations < 2)
{
exfat_error("too few continuations (%hhu)", continuations);
goto error;
}
if (continuations > 1 +
DIV_ROUND_UP(EXFAT_NAME_MAX, EXFAT_ENAME_MAX))
{
exfat_error("too many continuations (%hhu)", continuations);
goto error;
}
reference_checksum = le16_to_cpu(meta1->checksum);
actual_checksum = exfat_start_checksum(meta1);
*node = allocate_node();
if (*node == NULL)
{
rc = -ENOMEM;
goto error;
}
/* new node has zero reference counter */
(*node)->entry_cluster = it->cluster;
(*node)->entry_offset = it->offset;
init_node_meta1(*node, meta1);
namep = (*node)->name;
break;
case EXFAT_ENTRY_FILE_INFO:
if (continuations < 2)
{
exfat_error("unexpected continuation (%hhu)",
continuations);
goto error;
}
meta2 = (const struct exfat_entry_meta2*) entry;
if (meta2->flags & ~(EXFAT_FLAG_ALWAYS1 | EXFAT_FLAG_CONTIGUOUS))
{
exfat_error("unknown flags in meta2 (0x%hhx)", meta2->flags);
goto error;
}
init_node_meta2(*node, meta2);
actual_checksum = exfat_add_checksum(entry, actual_checksum);
real_size = le64_to_cpu(meta2->real_size);
/* empty files must be marked as non-contiguous */
if ((*node)->size == 0 && (meta2->flags & EXFAT_FLAG_CONTIGUOUS))
{
exfat_error("empty file marked as contiguous (0x%hhx)",
meta2->flags);
goto error;
}
/* directories must be aligned on at cluster boundary */
if (((*node)->flags & EXFAT_ATTRIB_DIR) &&
(*node)->size % CLUSTER_SIZE(*ef->sb) != 0)
{
exfat_error("directory has invalid size %"PRIu64" bytes",
(*node)->size);
goto error;
}
--continuations;
break;
case EXFAT_ENTRY_FILE_NAME:
if (continuations == 0)
{
exfat_error("unexpected continuation");
goto error;
}
file_name = (const struct exfat_entry_name*) entry;
actual_checksum = exfat_add_checksum(entry, actual_checksum);
memcpy(namep, file_name->name,
MIN(EXFAT_ENAME_MAX,
((*node)->name + EXFAT_NAME_MAX - namep)) *
sizeof(le16_t));
namep += EXFAT_ENAME_MAX;
if (--continuations == 0)
{
/*
There are two fields that contain file size. Maybe they
plan to add compression support in the future and one of
those fields is visible (uncompressed) size and the other
is real (compressed) size. Anyway, currently it looks like
exFAT does not support compression and both fields must be
equal.
There is an exception though: pagefile.sys (its real_size
is always 0).
*/
if (real_size != (*node)->size)
{
char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
exfat_get_name(*node, buffer, sizeof(buffer) - 1);
exfat_error("`%s' real size does not equal to size "
"(%"PRIu64" != %"PRIu64")", buffer,
real_size, (*node)->size);
goto error;
}
if (actual_checksum != reference_checksum)
{
char buffer[UTF8_BYTES(EXFAT_NAME_MAX) + 1];
exfat_get_name(*node, buffer, sizeof(buffer) - 1);
exfat_error("`%s' has invalid checksum (0x%hx != 0x%hx)",
buffer, actual_checksum, reference_checksum);
goto error;
}
if (fetch_next_entry(ef, parent, it) != 0)
goto error;
return 0; /* entry completed */
}
break;
case EXFAT_ENTRY_UPCASE:
if (ef->upcase != NULL)
break;
upcase = (const struct exfat_entry_upcase*) entry;
if (CLUSTER_INVALID(le32_to_cpu(upcase->start_cluster)))
{
exfat_error("invalid cluster 0x%x in upcase table",
le32_to_cpu(upcase->start_cluster));
goto error;
}
if (le64_to_cpu(upcase->size) == 0 ||
le64_to_cpu(upcase->size) > 0xffff * sizeof(uint16_t) ||
le64_to_cpu(upcase->size) % sizeof(uint16_t) != 0)
{
exfat_error("bad upcase table size (%"PRIu64" bytes)",
le64_to_cpu(upcase->size));
goto error;
}
ef->upcase = malloc(le64_to_cpu(upcase->size));
if (ef->upcase == NULL)
{
exfat_error("failed to allocate upcase table (%"PRIu64" bytes)",
le64_to_cpu(upcase->size));
rc = -ENOMEM;
goto error;
}
ef->upcase_chars = le64_to_cpu(upcase->size) / sizeof(le16_t);
if (exfat_pread(ef->dev, ef->upcase, le64_to_cpu(upcase->size),
exfat_c2o(ef, le32_to_cpu(upcase->start_cluster))) < 0)
{
exfat_error("failed to read upper case table "
"(%"PRIu64" bytes starting at cluster %#x)",
le64_to_cpu(upcase->size),
le32_to_cpu(upcase->start_cluster));
goto error;
}
break;
case EXFAT_ENTRY_BITMAP:
bitmap = (const struct exfat_entry_bitmap*) entry;
ef->cmap.start_cluster = le32_to_cpu(bitmap->start_cluster);
if (CLUSTER_INVALID(ef->cmap.start_cluster))
{
exfat_error("invalid cluster 0x%x in clusters bitmap",
ef->cmap.start_cluster);
goto error;
}
ef->cmap.size = le32_to_cpu(ef->sb->cluster_count) -
EXFAT_FIRST_DATA_CLUSTER;
if (le64_to_cpu(bitmap->size) < DIV_ROUND_UP(ef->cmap.size, 8))
{
exfat_error("invalid clusters bitmap size: %"PRIu64
" (expected at least %u)",
le64_to_cpu(bitmap->size),
DIV_ROUND_UP(ef->cmap.size, 8));
goto error;
}
/* FIXME bitmap can be rather big, up to 512 MB */
ef->cmap.chunk_size = ef->cmap.size;
ef->cmap.chunk = malloc(BMAP_SIZE(ef->cmap.chunk_size));
if (ef->cmap.chunk == NULL)
{
exfat_error("failed to allocate clusters bitmap chunk "
"(%"PRIu64" bytes)", le64_to_cpu(bitmap->size));
rc = -ENOMEM;
goto error;
}
if (exfat_pread(ef->dev, ef->cmap.chunk,
BMAP_SIZE(ef->cmap.chunk_size),
exfat_c2o(ef, ef->cmap.start_cluster)) < 0)
{
exfat_error("failed to read clusters bitmap "
"(%"PRIu64" bytes starting at cluster %#x)",
le64_to_cpu(bitmap->size), ef->cmap.start_cluster);
goto error;
}
break;
case EXFAT_ENTRY_LABEL:
label = (const struct exfat_entry_label*) entry;
if (label->length > EXFAT_ENAME_MAX)
{
exfat_error("too long label (%hhu chars)", label->length);
goto error;
}
if (utf16_to_utf8(ef->label, label->name,
sizeof(ef->label) - 1, EXFAT_ENAME_MAX) != 0)
goto error;
break;
default:
if (entry->type & EXFAT_ENTRY_VALID)
{
exfat_error("unknown entry type 0x%hhx", entry->type);
goto error;
}
break;
}
if (fetch_next_entry(ef, parent, it) != 0)
goto error;
}
/* we never reach here */
error:
free(*node);
*node = NULL;
return rc;
}
/*
* Size in bytes to size in clusters (rounded upwards).
*/
static uint32_t bytes2clusters(const struct exfat* ef, uint64_t bytes)
{
uint64_t cluster_size = CLUSTER_SIZE(*ef->sb);
return (bytes + cluster_size - 1) / cluster_size;
}
static const struct exfat_entry* get_entry_ptr(const struct exfat* ef,
const struct iterator* it)
{
return (const struct exfat_entry*)
(it->chunk + it->offset % CLUSTER_SIZE(*ef->sb));
}