int nxffs_findinode(FAR struct nxffs_volume_s *volume, FAR const char *name,
FAR struct nxffs_entry_s *entry)
{
off_t offset;
int ret;
/* Start with the first valid inode that was discovered when the volume
* was created (or modified after the last file system re-packing).
*/
offset = volume->inoffset;
/* Loop, checking each NXFFS inode until either: (1) we find the NXFFS inode
* with the matching name, or (2) we reach the end of data written on the
* media.
*/
for (;;)
{
/* Get the next, valid NXFFS inode entry */
ret = nxffs_nextentry(volume, offset, entry);
if (ret < 0)
{
fvdbg("No inode found: %d\n", -ret);
return ret;
}
/* Is this the NXFFS inode we are looking for? */
else if (strcmp(name, entry->name) == 0)
{
/* Yes, return success with the entry data in 'entry' */
return OK;
}
/* Discard this entry and try the next one. Here we set the
* next offset using the raw data length as the offset
* increment. This is, of course, not accurate because it
* does not account for the data headers that enclose the
* data. But it is guaranteed to be less than or equal to
* the correct offset and, hence, better then searching
* byte-for-byte.
*/
offset = nxffs_inodeend(volume, entry);
nxffs_freeentry(entry);
}
/* We won't get here, but for some compilers: */
return -ENOENT;
}
int nxffs_readdir(FAR struct inode *mountpt, FAR struct fs_dirent_s *dir)
{
FAR struct nxffs_volume_s *volume;
FAR struct nxffs_entry_s entry;
off_t offset;
int ret;
/* Sanity checks */
DEBUGASSERT(mountpt != NULL && mountpt->i_private != NULL);
/* Recover the file system state from the NuttX inode instance */
volume = mountpt->i_private;
ret = sem_wait(&volume->exclsem);
if (ret != OK)
{
goto errout;
}
/* Read the next inode header from the offset */
offset = dir->u.nxffs.nx_offset;
ret = nxffs_nextentry(volume, offset, &entry);
/* If the read was successful, then handle the reported inode. Note
* that when the last inode has been reported, the value -ENOENT will
* be returned.. which is correct for the readdir() method.
*/
if (ret == OK)
{
/* Return the filename and file type */
fvdbg("Offset %d: \"%s\"\n", entry.hoffset, entry.name);
dir->fd_dir.d_type = DTYPE_FILE;
strncpy(dir->fd_dir.d_name, entry.name, NAME_MAX+1);
/* Discard this entry and set the next offset. */
dir->u.nxffs.nx_offset = nxffs_inodeend(volume, &entry);
nxffs_freeentry(&entry);
ret = OK;
}
sem_post(&volume->exclsem);
errout:
return ret;
}
int nxffs_limits(FAR struct nxffs_volume_s *volume)
{
FAR struct nxffs_entry_s entry;
off_t block;
off_t offset;
bool noinodes = false;
int nerased;
int ret;
/* Get the offset to the first valid block on the FLASH */
block = 0;
ret = nxffs_validblock(volume, &block);
if (ret < 0)
{
fdbg("Failed to find a valid block: %d\n", -ret);
return ret;
}
/* Then find the first valid inode in or beyond the first valid block */
offset = block * volume->geo.blocksize;
ret = nxffs_nextentry(volume, offset, &entry);
if (ret < 0)
{
/* The value -ENOENT is special. This simply means that the FLASH
* was searched to the end and no valid inode was found... the file
* system is empty (or, in more perverse cases, all inodes are
* deleted or corrupted).
*/
if (ret != -ENOENT)
{
fdbg("nxffs_nextentry failed: %d\n", -ret);
return ret;
}
/* Set a flag the just indicates that no inodes were found. Later,
* we will set the location of the first inode to be the same as
* the location of the free FLASH region.
*/
fvdbg("No inodes found\n");
noinodes = true;
}
else
{
/* Save the offset to the first inode */
volume->inoffset = entry.hoffset;
fvdbg("First inode at offset %d\n", volume->inoffset);
/* Discard this entry and set the next offset. */
offset = nxffs_inodeend(volume, &entry);
nxffs_freeentry(&entry);
}
/* Now, search for the last valid entry */
if (!noinodes)
{
while ((ret = nxffs_nextentry(volume, offset, &entry)) == OK)
{
/* Discard the entry and guess the next offset. */
offset = nxffs_inodeend(volume, &entry);
nxffs_freeentry(&entry);
}
fvdbg("Last inode before offset %d\n", offset);
}
/* No inodes were found after this offset. Now search for a block of
* erased flash.
*/
nxffs_ioseek(volume, offset);
nerased = 0;
for (;;)
{
int ch = nxffs_getc(volume, 1);
if (ch < 0)
{
/* Failed to read the next byte... this could mean that the FLASH
* is full?
*/
if (volume->ioblock + 1 >= volume->nblocks &&
volume->iooffset + 1 >= volume->geo.blocksize)
{
/* Yes.. the FLASH is full. Force the offsets to the end of FLASH */
volume->froffset = volume->nblocks * volume->geo.blocksize;
fvdbg("Assume no free FLASH, froffset: %d\n", volume->froffset);
if (noinodes)
{
volume->inoffset = volume->froffset;
fvdbg("No inodes, inoffset: %d\n", volume->inoffset);
}
return OK;
}
// No? Then it is some other failure that we do not know how to handle
fdbg("nxffs_getc failed: %d\n", -ch);
return ch;
}
/* Check for another erased byte */
else if (ch == CONFIG_NXFFS_ERASEDSTATE)
{
/* If we have encountered NXFFS_NERASED number of consecutive
* erased bytes, then presume we have reached the end of valid
* data.
*/
if (++nerased >= NXFFS_NERASED)
{
/* Okay.. we have a long stretch of erased FLASH in a valid
* FLASH block. Let's say that this is the beginning of
* the free FLASH region.
*/
volume->froffset = offset;
fvdbg("Free FLASH region begins at offset: %d\n", volume->froffset);
if (noinodes)
{
volume->inoffset = offset;
fvdbg("First inode at offset %d\n", volume->inoffset);
}
return OK;
}
}
else
{
offset += nerased + 1;
nerased = 0;
}
}
/* Won't get here */
return OK;
}
static int nxffs_rdentry(FAR struct nxffs_volume_s *volume, off_t offset,
FAR struct nxffs_entry_s *entry)
{
struct nxffs_inode_s inode;
uint32_t ecrc;
uint32_t crc;
uint8_t state;
int namlen;
int ret;
DEBUGASSERT(volume && entry);
memset(entry, 0, sizeof(struct nxffs_entry_s));
/* Read the header at the FLASH offset */
nxffs_ioseek(volume, offset);
memcpy(&inode, &volume->cache[volume->iooffset], SIZEOF_NXFFS_INODE_HDR);
/* Check if the file state is recognized. */
state = inode.state;
if (state != INODE_STATE_FILE && state != INODE_STATE_DELETED)
{
/* This can't be a valid inode.. don't bother with the rest */
ret = -ENOENT;
goto errout_no_offset;
}
/* Copy the packed header into the user-friendly buffer */
entry->hoffset = offset;
entry->noffset = nxffs_rdle32(inode.noffs);
entry->doffset = nxffs_rdle32(inode.doffs);
entry->utc = nxffs_rdle32(inode.utc);
entry->datlen = nxffs_rdle32(inode.datlen);
/* Modify the packed header and perform the (partial) CRC calculation */
ecrc = nxffs_rdle32(inode.crc);
inode.state = CONFIG_NXFFS_ERASEDSTATE;
memset(inode.crc, 0, 4);
crc = crc32((FAR const uint8_t *)&inode, SIZEOF_NXFFS_INODE_HDR);
/* Allocate memory to hold the variable-length file name */
namlen = inode.namlen;
entry->name = (FAR char *)kmalloc(namlen + 1);
if (!entry->name)
{
fdbg("ERROR: Failed to allocate name, namlen: %d\n", namlen);
ret = -ENOMEM;
goto errout_no_offset;
}
/* Seek to the expected location of the name in FLASH */
nxffs_ioseek(volume, entry->noffset);
/* Make sure that the block is in memory (the name may not be in the
* same block as the inode header.
*/
ret = nxffs_rdcache(volume, volume->ioblock);
if (ret < 0)
{
fdbg("ERROR: nxffsx_rdcache failed: %d\n", -ret);
goto errout_with_name;
}
/* Read the file name from the expected offset in FLASH */
memcpy(entry->name, &volume->cache[volume->iooffset], namlen);
entry->name[namlen] = '\0';
/* Finish the CRC calculation and verify the entry */
crc = crc32part((FAR const uint8_t *)entry->name, namlen, crc);
if (crc != ecrc)
{
fdbg("ERROR: CRC entry: %08x CRC calculated: %08x\n", ecrc, crc);
ret = -EIO;
goto errout_with_name;
}
/* We have a good inode header.. but it still could a deleted file.
* Check the file state.
*/
if (state != INODE_STATE_FILE)
{
/* It is a deleted file. But still, the data offset and the
* start size are good so we can use this information to advance
* further in FLASH memory and reduce the search time.
*/
offset = nxffs_inodeend(volume, entry);
nxffs_freeentry(entry);
ret = -ENOENT;
goto errout;
}
/* Everything is good.. leave the offset pointing to the valid inode
* header.
*/
return OK;
/* On errors where we are suspicious of the validity of the inode header,
* we need to increment the file position to just after the "good" magic
* word.
*/
errout_with_name:
nxffs_freeentry(entry);
errout_no_offset:
offset += NXFFS_MAGICSIZE;
errout:
nxffs_ioseek(volume, offset);
return ret;
}
