int nxffs_rdblkhdr(FAR struct nxffs_volume_s *volume, off_t offset,
FAR uint16_t *datlen)
{
struct nxffs_data_s blkhdr;
uint32_t ecrc;
uint32_t crc;
uint16_t doffset;
uint16_t dlen;
int ret;
/* Make sure that the block containing the data block header is in the cache */
nxffs_ioseek(volume, offset);
ret = nxffs_rdcache(volume, volume->ioblock);
if (ret < 0)
{
fdbg("ERROR: Failed to read data into cache: %d\n", ret);
return ret;
}
/* Read the header at the FLASH offset */
doffset = volume->iooffset;
memcpy(&blkhdr, &volume->cache[doffset], SIZEOF_NXFFS_DATA_HDR);
/* Extract the data length */
dlen = nxffs_rdle16(blkhdr.datlen);
/* Get the offset to the beginning of the data */
doffset += SIZEOF_NXFFS_DATA_HDR;
/* Make sure that all of the data fits within the block */
if ((uint32_t)doffset + (uint32_t)dlen > (uint32_t)volume->geo.blocksize)
{
fdbg("ERROR: Data length=%d is unreasonable at offset=%d\n", dlen, doffset);
return -EIO;
}
/* Extract the expected CRC and calculate the CRC of the data block */
ecrc = nxffs_rdle32(blkhdr.crc);
nxffs_wrle32(blkhdr.crc, 0);
crc = crc32((FAR const uint8_t *)&blkhdr, SIZEOF_NXFFS_DATA_HDR);
crc = crc32part(&volume->cache[doffset], dlen, crc);
if (crc != ecrc)
{
fdbg("ERROR: CRC failure\n");
return -EIO;
}
/* Looks good! Return the data length and success */
*datlen = dlen;
return OK;
}
static inline ssize_t nxffs_analyzedata(FAR struct nxffs_blkinfo_s *blkinfo,
int offset)
{
struct nxffs_data_s dathdr;
uint32_t ecrc;
uint16_t datlen;
uint32_t crc;
/* Copy and unpack the data block header */
memcpy(&dathdr, &blkinfo->buffer[offset], SIZEOF_NXFFS_DATA_HDR);
ecrc = nxffs_rdle32(dathdr.crc);
datlen = nxffs_rdle16(dathdr.datlen);
/* Sanity checks */
if (offset + SIZEOF_NXFFS_DATA_HDR + datlen > blkinfo->geo.blocksize)
{
/* Data does not fit in within the block, this can't be a data block */
return ERROR;
}
/* Calculate the CRC */
nxffs_wrle32(dathdr.crc, 0);
crc = crc32((FAR const uint8_t *)&dathdr, SIZEOF_NXFFS_DATA_HDR);
crc = crc32part(&blkinfo->buffer[offset + SIZEOF_NXFFS_DATA_HDR], datlen, crc);
if (crc != ecrc)
{
syslog(LOG_NOTICE, g_format,
blkinfo->block, offset, "DATA ", "CRC BAD", datlen);
return ERROR;
}
/* If must be a good header */
if (blkinfo->verbose)
{
syslog(LOG_NOTICE, g_format,
blkinfo->block, offset, "DATA ", "OK ", datlen);
}
return SIZEOF_NXFFS_DATA_HDR + datlen;
}
