/*
* __wt_log_system_record --
* Write a system log record for the previous LSN.
*/
int
__wt_log_system_record(
WT_SESSION_IMPL *session, WT_FH *log_fh, WT_LSN *lsn)
{
WT_DECL_ITEM(logrec_buf);
WT_DECL_RET;
WT_LOG *log;
WT_LOG_RECORD *logrec;
WT_LOGSLOT tmp;
WT_MYSLOT myslot;
const char *fmt = WT_UNCHECKED_STRING(I);
uint32_t rectype = WT_LOGREC_SYSTEM;
size_t recsize;
log = S2C(session)->log;
WT_RET(__wt_logrec_alloc(session, log->allocsize, &logrec_buf));
memset((uint8_t *)logrec_buf->mem, 0, log->allocsize);
WT_ERR(__wt_struct_size(session, &recsize, fmt, rectype));
WT_ERR(__wt_struct_pack(session,
(uint8_t *)logrec_buf->data + logrec_buf->size, recsize, fmt,
rectype));
logrec_buf->size += recsize;
WT_ERR(__wt_logop_prev_lsn_pack(session, logrec_buf, lsn));
WT_ASSERT(session, logrec_buf->size <= log->allocsize);
logrec = (WT_LOG_RECORD *)logrec_buf->mem;
/*
* We know system records are this size. And we have to adjust
* the size now because we're not going through the normal log
* write path and the packing functions needed the correct offset
* earlier.
*/
logrec_buf->size = logrec->len = log->allocsize;
/* We do not compress nor encrypt this record. */
logrec->checksum = 0;
logrec->flags = 0;
__wt_log_record_byteswap(logrec);
logrec->checksum = __wt_checksum(logrec, log->allocsize);
#ifdef WORDS_BIGENDIAN
logrec->checksum = __wt_bswap32(logrec->checksum);
#endif
WT_CLEAR(tmp);
memset(&myslot, 0, sizeof(myslot));
myslot.slot = &tmp;
__wt_log_slot_activate(session, &tmp);
/*
* Override the file handle to the one we're using.
*/
tmp.slot_fh = log_fh;
WT_ERR(__wt_log_fill(session, &myslot, true, logrec_buf, NULL));
err: __wt_logrec_free(session, &logrec_buf);
return (ret);
}
/*
* __wt_decrypt --
* Common code to decrypt and verify the encrypted data in a
* WT_ITEM and return the decrypted buffer.
*/
int
__wt_decrypt(WT_SESSION_IMPL *session,
WT_ENCRYPTOR *encryptor, size_t skip, WT_ITEM *in, WT_ITEM *out)
{
size_t encryptor_data_len, result_len;
uint32_t encrypt_len;
uint8_t *dst, *src;
encrypt_len =
WT_STORE_SIZE(*((uint32_t *)((uint8_t *)in->data + skip)));
#ifdef WORDS_BIGENDIAN
encrypt_len = __wt_bswap32(encrypt_len);
#endif
if (encrypt_len > in->size)
WT_RET_MSG(session, WT_ERROR,
"corrupted encrypted item: padded size less than "
"actual size");
/*
* We're allocating the number of bytes we're expecting
* from decryption plus the unencrypted header.
*/
WT_RET(__wt_buf_initsize(session, out, encrypt_len));
src = (uint8_t *)in->data + skip + WT_ENCRYPT_LEN_SIZE;
encryptor_data_len = encrypt_len - (skip + WT_ENCRYPT_LEN_SIZE);
dst = (uint8_t *)out->mem + skip;
WT_RET(encryptor->decrypt(encryptor, &session->iface,
src, encryptor_data_len, dst, encryptor_data_len, &result_len));
/*
* We require encryption to be byte for byte. It should not expand
* the data.
*/
WT_ASSERT(session, result_len <= encryptor_data_len);
/*
* Copy in the skipped header bytes.
*/
memcpy(out->mem, in->data, skip);
/*
* Set the real result length in the output buffer including the skipped
* header size. The encryptor may have done its own padding so the
* returned result length is the real data length after decryption
* removes any of its padding.
*/
out->size = result_len + skip;
return (0);
}
/*
* __wt_encrypt --
* Common code to encrypt a WT_ITEM and return the encrypted buffer.
*/
int
__wt_encrypt(WT_SESSION_IMPL *session,
WT_KEYED_ENCRYPTOR *kencryptor, size_t skip, WT_ITEM *in, WT_ITEM *out)
{
size_t dst_len, result_len, src_len;
uint32_t *unpadded_lenp;
uint8_t *dst, *src;
/* Skip the header bytes of the source data. */
src = (uint8_t *)in->mem + skip;
src_len = in->size - skip;
unpadded_lenp = (uint32_t *)((uint8_t *)out->mem + skip);
/*
* Skip the header bytes and the length we store in the destination
* data. Add in the encryptor size constant to the expected destination
* length.
*/
dst = (uint8_t *)out->mem + skip + WT_ENCRYPT_LEN_SIZE;
dst_len = src_len + kencryptor->size_const;
WT_RET(kencryptor->encryptor->encrypt(kencryptor->encryptor,
&session->iface, src, src_len, dst, dst_len, &result_len));
/*
* We require encryption to be byte for byte. It should never expand
* the data.
*/
WT_ASSERT(session, result_len <= dst_len);
/*
* The final result length includes the skipped lengths.
*/
result_len += skip + WT_ENCRYPT_LEN_SIZE;
/*
* Store original size so we know how much space is needed on the
* decryption side.
*/
*unpadded_lenp = WT_STORE_SIZE(result_len);
#ifdef WORDS_BIGENDIAN
*unpadded_lenp = __wt_bswap32(*unpadded_lenp);
#endif
/*
* Copy in the skipped header bytes, set the final data size.
*/
memcpy(out->mem, in->mem, skip);
out->size = result_len;
return (0);
}
/*
* __wt_block_write_off --
* Write a buffer into a block, returning the block's offset, size and
* checksum.
*/
int
__wt_block_write_off(WT_SESSION_IMPL *session, WT_BLOCK *block,
WT_ITEM *buf, wt_off_t *offsetp, uint32_t *sizep, uint32_t *cksump,
bool data_cksum, bool caller_locked)
{
WT_BLOCK_HEADER *blk;
WT_DECL_RET;
WT_FH *fh;
size_t align_size;
wt_off_t offset;
uint32_t cksum;
bool local_locked;
fh = block->fh;
/*
* Clear the block header to ensure all of it is initialized, even the
* unused fields.
*/
blk = WT_BLOCK_HEADER_REF(buf->mem);
memset(blk, 0, sizeof(*blk));
/*
* Swap the page-header as needed; this doesn't belong here, but it's
* the best place to catch all callers.
*/
__wt_page_header_byteswap(buf->mem);
/* Buffers should be aligned for writing. */
if (!F_ISSET(buf, WT_ITEM_ALIGNED)) {
WT_ASSERT(session, F_ISSET(buf, WT_ITEM_ALIGNED));
WT_RET_MSG(session, EINVAL,
"direct I/O check: write buffer incorrectly allocated");
}
/*
* Align the size to an allocation unit.
*
* The buffer must be big enough for us to zero to the next allocsize
* boundary, this is one of the reasons the btree layer must find out
* from the block-manager layer the maximum size of the eventual write.
*/
align_size = WT_ALIGN(buf->size, block->allocsize);
if (align_size > buf->memsize) {
WT_ASSERT(session, align_size <= buf->memsize);
WT_RET_MSG(session, EINVAL,
"buffer size check: write buffer incorrectly allocated");
}
if (align_size > UINT32_MAX) {
WT_ASSERT(session, align_size <= UINT32_MAX);
WT_RET_MSG(session, EINVAL,
"buffer size check: write buffer too large to write");
}
/* Zero out any unused bytes at the end of the buffer. */
memset((uint8_t *)buf->mem + buf->size, 0, align_size - buf->size);
/*
* Set the disk size so we don't have to incrementally read blocks
* during salvage.
*/
blk->disk_size = WT_STORE_SIZE(align_size);
/*
* Update the block's checksum: if our caller specifies, checksum the
* complete data, otherwise checksum the leading WT_BLOCK_COMPRESS_SKIP
* bytes. The assumption is applications with good compression support
* turn off checksums and assume corrupted blocks won't decompress
* correctly. However, if compression failed to shrink the block, the
* block wasn't compressed, in which case our caller will tell us to
* checksum the data to detect corruption. If compression succeeded,
* we still need to checksum the first WT_BLOCK_COMPRESS_SKIP bytes
* because they're not compressed, both to give salvage a quick test
* of whether a block is useful and to give us a test so we don't lose
* the first WT_BLOCK_COMPRESS_SKIP bytes without noticing.
*
* Checksum a little-endian version of the header, and write everything
* in little-endian format. The checksum is (potentially) returned in a
* big-endian format, swap it into place in a separate step.
*/
blk->flags = 0;
if (data_cksum)
F_SET(blk, WT_BLOCK_DATA_CKSUM);
blk->cksum = 0;
__wt_block_header_byteswap(blk);
blk->cksum = cksum = __wt_cksum(
buf->mem, data_cksum ? align_size : WT_BLOCK_COMPRESS_SKIP);
#ifdef WORDS_BIGENDIAN
blk->cksum = __wt_bswap32(blk->cksum);
#endif
/* Pre-allocate some number of extension structures. */
WT_RET(__wt_block_ext_prealloc(session, 5));
/*
* Acquire a lock, if we don't already hold one.
* Allocate space for the write, and optionally extend the file (note
* the block-extend function may release the lock).
* Release any locally acquired lock.
*/
local_locked = false;
if (!caller_locked) {
__wt_spin_lock(session, &block->live_lock);
local_locked = true;
}
ret = __wt_block_alloc(session, block, &offset, (wt_off_t)align_size);
if (ret == 0)
ret = __wt_block_extend(
session, block, fh, offset, align_size, &local_locked);
if (local_locked)
__wt_spin_unlock(session, &block->live_lock);
WT_RET(ret);
/* Write the block. */
if ((ret =
__wt_write(session, fh, offset, align_size, buf->mem)) != 0) {
if (!caller_locked)
__wt_spin_lock(session, &block->live_lock);
WT_TRET(__wt_block_off_free(
session, block, offset, (wt_off_t)align_size));
if (!caller_locked)
__wt_spin_unlock(session, &block->live_lock);
WT_RET(ret);
}
#ifdef HAVE_SYNC_FILE_RANGE
/*
* Optionally schedule writes for dirty pages in the system buffer
* cache, but only if the current session can wait.
*/
if (block->os_cache_dirty_max != 0 &&
(block->os_cache_dirty += align_size) > block->os_cache_dirty_max &&
__wt_session_can_wait(session)) {
block->os_cache_dirty = 0;
WT_RET(__wt_fsync_async(session, fh));
}
#endif
#ifdef HAVE_POSIX_FADVISE
/* Optionally discard blocks from the system buffer cache. */
if (block->os_cache_max != 0 &&
(block->os_cache += align_size) > block->os_cache_max) {
block->os_cache = 0;
if ((ret = posix_fadvise(fh->fd,
(wt_off_t)0, (wt_off_t)0, POSIX_FADV_DONTNEED)) != 0)
WT_RET_MSG(
session, ret, "%s: posix_fadvise", block->name);
}
#endif
WT_STAT_FAST_CONN_INCR(session, block_write);
WT_STAT_FAST_CONN_INCRV(session, block_byte_write, align_size);
WT_RET(__wt_verbose(session, WT_VERB_WRITE,
"off %" PRIuMAX ", size %" PRIuMAX ", cksum %" PRIu32,
(uintmax_t)offset, (uintmax_t)align_size, cksum));
*offsetp = offset;
*sizep = WT_STORE_SIZE(align_size);
*cksump = cksum;
return (0);
}
