if ((ret = __db_seek(dblp->c_fd, 0, 0, nlsn.offset, SEEK_SET)) != 0) {
if ((ret = __db_seek(dblp->c_fd, 0, 0, nlsn.offset, 0, SEEK_SET)) != 0) {
__log_get(dblp, alsn, dbt, flags, silent)	DB_LOG *dblp;	DB_LSN *alsn;	DBT *dbt;	int flags, silent;{	DB_LSN nlsn;	HDR hdr;	LOG *lp;	size_t len;	ssize_t nr;	int cnt, ret;	char *np, *tbuf;	const char *fail;	void *p, *shortp;	lp = dblp->lp;	fail = np = tbuf = NULL;	nlsn = dblp->c_lsn;	switch (flags) {	case DB_CHECKPOINT:		nlsn = lp->c_lsn;		if (IS_ZERO_LSN(nlsn)) {			__db_err(dblp->dbenv,	"log_get: unable to find checkpoint record: no checkpoint set.");			ret = ENOENT;			goto err2;		}		break;	case DB_NEXT:				/* Next log record. */		if (!IS_ZERO_LSN(nlsn)) {			/* Increment the cursor by the cursor record size. */			nlsn.offset += dblp->c_len;			break;		}		/* FALLTHROUGH */	case DB_FIRST:				/* Find the first log record. */		/* Find the first log file. */		if ((ret = __log_find(dblp, 1, &cnt)) != 0)			goto err2;		/*		 * We may have only entered records in the buffer, and not		 * yet written a log file.  If no log files were found and		 * there's anything in the buffer, it belongs to file 1.		 */		if (cnt == 0)			cnt = 1;		nlsn.file = cnt;		nlsn.offset = 0;		break;	case DB_CURRENT:			/* Current log record. */		break;	case DB_PREV:				/* Previous log record. */		if (!IS_ZERO_LSN(nlsn)) {			/* If at start-of-file, move to the previous file. */			if (nlsn.offset == 0) {				if (nlsn.file == 1 ||				    __log_valid(dblp, NULL, nlsn.file - 1) != 0)					return (DB_NOTFOUND);				--nlsn.file;				nlsn.offset = dblp->c_off;			} else				nlsn.offset = dblp->c_off;			break;		}		/* FALLTHROUGH */	case DB_LAST:				/* Last log record. */		nlsn.file = lp->lsn.file;		nlsn.offset = lp->lsn.offset - lp->len;		break;	case DB_SET:				/* Set log record. */		nlsn = *alsn;		break;	}retry:	/* Return 1 if the request is past end-of-file. */	if (nlsn.file > lp->lsn.file ||	    (nlsn.file == lp->lsn.file && nlsn.offset >= lp->lsn.offset))		return (DB_NOTFOUND);	/* If we've switched files, discard the current fd. */	if (dblp->c_lsn.file != nlsn.file && dblp->c_fd != -1) {		(void)__db_close(dblp->c_fd);		dblp->c_fd = -1;	}	/* If the entire record is in the in-memory buffer, copy it out. */	if (nlsn.file == lp->lsn.file && nlsn.offset >= lp->w_off) {		/* Copy the header. */		p = lp->buf + (nlsn.offset - lp->w_off);		memcpy(&hdr, p, sizeof(HDR));		/* Copy the record. */		len = hdr.len - sizeof(HDR);		if ((ret = __db_retcopy(dbt, (u_int8_t *)p + sizeof(HDR),		    len, &dblp->c_dbt.data, &dblp->c_dbt.ulen, NULL)) != 0)			goto err1;		goto cksum;	}	/* Acquire a file descriptor. */	if (dblp->c_fd == -1) {		if ((ret = __log_name(dblp, nlsn.file, &np)) != 0)			goto err1;		if ((ret = __db_open(np, DB_RDONLY | DB_SEQUENTIAL,		    DB_RDONLY | DB_SEQUENTIAL, 0, &dblp->c_fd)) != 0) {			fail = np;			goto err1;		}		__db_free(np);		np = NULL;	}	/* Seek to the header offset and read the header. */	if ((ret = __db_seek(dblp->c_fd, 0, 0, nlsn.offset, SEEK_SET)) != 0) {		fail = "seek";		goto err1;	}	if ((ret = __db_read(dblp->c_fd, &hdr, sizeof(HDR), &nr)) != 0) {		fail = "read";		goto err1;	}	if (nr == sizeof(HDR))		shortp = NULL;	else {		/* If read returns EOF, try the next file. */		if (nr == 0) {			if (flags != DB_NEXT || nlsn.file == lp->lsn.file)				goto corrupt;			/* Move to the next file. */			++nlsn.file;			nlsn.offset = 0;			goto retry;		}		/*		 * If read returns a short count the rest of the record has		 * to be in the in-memory buffer.		 */		if (lp->b_off < sizeof(HDR) - nr)			goto corrupt;		/* Get the rest of the header from the in-memory buffer. */		memcpy((u_int8_t *)&hdr + nr, lp->buf, sizeof(HDR) - nr);		shortp = lp->buf + (sizeof(HDR) - nr);	}	/*	 * Check for buffers of 0's, that's what we usually see during	 * recovery, although it's certainly not something on which we	 * can depend.	 */	if (hdr.len <= sizeof(HDR))		goto corrupt;	len = hdr.len - sizeof(HDR);	/* If we've already moved to the in-memory buffer, fill from there. */	if (shortp != NULL) {		if (lp->b_off < ((u_int8_t *)shortp - lp->buf) + len)			goto corrupt;		if ((ret = __db_retcopy(dbt, shortp, len,		    &dblp->c_dbt.data, &dblp->c_dbt.ulen, NULL)) != 0)			goto err1;		goto cksum;	}	/* Allocate temporary memory to hold the record. */	if ((tbuf = (char *)__db_malloc(len)) == NULL) {		ret = ENOMEM;		goto err1;	}	/*	 * Read the record into the buffer.  If read returns a short count,	 * there was an error or the rest of the record is in the in-memory	 * buffer.  Note, the information may be garbage if we're in recovery,	 * so don't read past the end of the buffer's memory.	 */	if ((ret = __db_read(dblp->c_fd, tbuf, len, &nr)) != 0) {		fail = "read";		goto err1;	}	if (len - nr > sizeof(lp->buf))		goto corrupt;	if (nr != (ssize_t)len) {		if (lp->b_off < len - nr)			goto corrupt;		/* Get the rest of the record from the in-memory buffer. */		memcpy((u_int8_t *)tbuf + nr, lp->buf, len - nr);	}	/* Copy the record into the user's DBT. */	if ((ret = __db_retcopy(dbt, tbuf, len,	    &dblp->c_dbt.data, &dblp->c_dbt.ulen, NULL)) != 0)		goto err1;	__db_free(tbuf);	tbuf = NULL;cksum:	if (hdr.cksum != __ham_func4(dbt->data, dbt->size)) {		if (!silent)			__db_err(dblp->dbenv, "log_get: checksum mismatch");		goto corrupt;	}	/* Update the cursor and the return lsn. */	dblp->c_off = hdr.prev;	dblp->c_len = hdr.len;	dblp->c_lsn = *alsn = nlsn;	return (0);corrupt:/*	 * This is the catchall -- for some reason we didn't find enough	 * information or it wasn't reasonable information, and it wasn't	 * because a system call failed.	 */	ret = EIO;	fail = "read";err1:	if (!silent)		if (fail == NULL)			__db_err(dblp->dbenv, "log_get: %s", strerror(ret));		else			__db_err(dblp->dbenv,			    "log_get: %s: %s", fail, strerror(ret));err2:	if (np != NULL)		__db_free(np);	if (tbuf != NULL)		__db_free(tbuf);	return (ret);}