diff options
Diffstat (limited to 'src/H5Fio.c')
| -rw-r--r-- | src/H5Fio.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/src/H5Fio.c b/src/H5Fio.c index 4f15017..bd8c39a 100644 --- a/src/H5Fio.c +++ b/src/H5Fio.c @@ -236,3 +236,109 @@ done: FUNC_LEAVE_NOAPI(ret_value); } /* end H5F_evict_tagged_metadata */ + +/*------------------------------------------------------------------------- + * Function: H5F_get_checksums + * + * Purpose: Decode checksum stored in the buffer + * Calculate checksum for the data in the buffer + * + * Return: Non-negative on success/Negative on failure + * + * Programmer: Vailin Choi; Sept 2013 + * + *------------------------------------------------------------------------- + */ +herr_t +H5F_get_checksums(uint8_t *buf, size_t chk_size, uint32_t *s_chksum/*out*/, uint32_t *c_chksum/*out*/) +{ + uint32_t stored_chksum; /* Stored metadata checksum value */ + uint32_t computed_chksum; /* Computed metadata checksum value */ + const uint8_t *chk_p; /* Pointer into raw data buffer */ + + FUNC_ENTER_NOAPI_NOINIT_NOERR + + /* Check arguments */ + HDassert(buf); + HDassert(chk_size); + + /* Compute checksum for the buffer */ + computed_chksum = H5_checksum_metadata(buf, chk_size - H5_SIZEOF_CHKSUM, 0); + + /* Offset to the checksum in the buffer */ + chk_p = buf + chk_size - H5_SIZEOF_CHKSUM; + + /* Decode the checksum stored in the buffer */ + UINT32DECODE(chk_p, stored_chksum); + + /* Return the stored checksum */ + if(s_chksum) + *s_chksum = stored_chksum; + + /* Return the computed checksum */ + if(c_chksum) + *c_chksum = computed_chksum; + + FUNC_LEAVE_NOAPI(SUCCEED) +} /* end H5F_get_chksums() */ + + +/*------------------------------------------------------------------------- + * Function: H5F_read_check_meatadata + * + * Purpose: Attempts to read and validate a piece of meatadata that has + * checksum as follows: + * a) read the piece of metadata + * b) calculate checksum for the buffer of metadata + * c) decode the checksum stored in the buffer of metadata + d) compare the computed checksum with its stored checksum + * The library will perform (a) to (d) above for "f->read_attempts" + * times or until the checksum comparison in (d) passes. + * + * Return: Non-negative on success/Negative on failure + * + * Programmer: Vailin Choi; Sept 2013 + * + *------------------------------------------------------------------------- + */ +herr_t +H5F_read_check_metadata(const H5F_t *f, H5FD_mem_t type, haddr_t addr, size_t read_size, size_t chk_size, + hid_t dxpl_id, uint8_t *buf/*out*/, uint32_t *chksum/*out*/) +{ + size_t tries, max_tries; + uint32_t stored_chksum; /* Stored metadata checksum value */ + uint32_t computed_chksum; /* Computed metadata checksum value */ + herr_t ret_value = SUCCEED; + + FUNC_ENTER_NOAPI(FAIL) + + /* Get the # of read attempts */ + max_tries = tries = f->read_attempts; + + do { + /* Read header from disk */ + if(H5F_block_read(f, type, addr, read_size, dxpl_id, buf) < 0) + HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "unable to read metadata") + + /* Get stored and computed checksums */ + H5F_get_checksums(buf, chk_size, &stored_chksum, &computed_chksum); + + /* Verify checksum */ + if(stored_chksum == computed_chksum) + break; + + } while(--tries); + + if(tries == 0) + HGOTO_ERROR(H5E_IO, H5E_READERROR, FAIL, "incorrect metadatda checksum after all read attempts (%u) for %u bytes:c_chksum=%u, s_chkum=%u", + max_tries, chk_size, computed_chksum, stored_chksum) + else if((max_tries - tries + 1) > 1) + HDfprintf(stderr, "%s: SUCCESS after %u attempts; type=%u\n", FUNC, max_tries - tries + 1, type); + + /* Return the computed checksum */ + if(chksum) + *chksum = computed_chksum; + +done: + FUNC_LEAVE_NOAPI(ret_value); +} /* end H5F_read_check_metadata */ |