X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb2%2Ftdb.c;h=a7aa4572382b0f8b10ef03c4adc08599fd7e7293;hp=8bebe2af206b2a361734a687f062722fc2c8a626;hb=98c754ffe65bc335f66161d6cc8705d4ea2710ec;hpb=acfeff3aee13b58cb114e7f82afeb2d159e80c05;ds=sidebyside

diff --git a/ccan/tdb2/tdb.c b/ccan/tdb2/tdb.c
index 8bebe2af..a7aa4572 100644
--- a/ccan/tdb2/tdb.c
+++ b/ccan/tdb2/tdb.c
@@ -1,428 +1,24 @@
+ /*
+   Trivial Database 2: fetch, store and misc routines.
+   Copyright (C) Rusty Russell 2010
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with this library; if not, see <http://www.gnu.org/licenses/>.
+*/
 #include "private.h"
-#include <ccan/tdb2/tdb2.h>
-#include <assert.h>
+#include <ccan/asprintf/asprintf.h>
 #include <stdarg.h>
 
-/* The null return. */
-struct tdb_data tdb_null = { .dptr = NULL, .dsize = 0 };
-
-/* all contexts, to ensure no double-opens (fcntl locks don't nest!) */
-static struct tdb_context *tdbs = NULL;
-
-static bool tdb_already_open(dev_t device, ino_t ino)
-{
-	struct tdb_context *i;
-	
-	for (i = tdbs; i; i = i->next) {
-		if (i->device == device && i->inode == ino) {
-			return true;
-		}
-	}
-
-	return false;
-}
-
-static bool read_all(int fd, void *buf, size_t len)
-{
-	while (len) {
-		ssize_t ret;
-		ret = read(fd, buf, len);
-		if (ret < 0)
-			return false;
-		if (ret == 0) {
-			/* ETOOSHORT? */
-			errno = EWOULDBLOCK;
-			return false;
-		}
-		buf = (char *)buf + ret;
-		len -= ret;
-	}
-	return true;
-}
-
-static uint64_t random_number(struct tdb_context *tdb)
-{
-	int fd;
-	uint64_t ret = 0;
-	struct timeval now;
-
-	fd = open("/dev/urandom", O_RDONLY);
-	if (fd >= 0) {
-		if (read_all(fd, &ret, sizeof(ret))) {
-			close(fd);
-			return ret;
-		}
-		close(fd);
-	}
-	/* FIXME: Untested!  Based on Wikipedia protocol description! */
-	fd = open("/dev/egd-pool", O_RDWR);
-	if (fd >= 0) {
-		/* Command is 1, next byte is size we want to read. */
-		char cmd[2] = { 1, sizeof(uint64_t) };
-		if (write(fd, cmd, sizeof(cmd)) == sizeof(cmd)) {
-			char reply[1 + sizeof(uint64_t)];
-			int r = read(fd, reply, sizeof(reply));
-			if (r > 1) {
-				/* Copy at least some bytes. */
-				memcpy(&ret, reply+1, r - 1);
-				if (reply[0] == sizeof(uint64_t)
-				    && r == sizeof(reply)) {
-					close(fd);
-					return ret;
-				}
-			}
-		}
-		close(fd);
-	}
-
-	/* Fallback: pid and time. */
-	gettimeofday(&now, NULL);
-	ret = getpid() * 100132289ULL + now.tv_sec * 1000000ULL + now.tv_usec;
-	tdb_logerr(tdb, TDB_SUCCESS, TDB_LOG_WARNING,
-		   "tdb_open: random from getpid and time");
-	return ret;
-}
-
-struct new_database {
-	struct tdb_header hdr;
-	struct tdb_freetable ftable;
-};
-
-/* initialise a new database */
-static enum TDB_ERROR tdb_new_database(struct tdb_context *tdb,
-				       struct tdb_attribute_seed *seed,
-				       struct tdb_header *hdr)
-{
-	/* We make it up in memory, then write it out if not internal */
-	struct new_database newdb;
-	unsigned int magic_len;
-	ssize_t rlen;
-	enum TDB_ERROR ecode;
-
-	/* Fill in the header */
-	newdb.hdr.version = TDB_VERSION;
-	if (seed)
-		newdb.hdr.hash_seed = seed->seed;
-	else
-		newdb.hdr.hash_seed = random_number(tdb);
-	newdb.hdr.hash_test = TDB_HASH_MAGIC;
-	newdb.hdr.hash_test = tdb->khash(&newdb.hdr.hash_test,
-					 sizeof(newdb.hdr.hash_test),
-					 newdb.hdr.hash_seed,
-					 tdb->hash_priv);
-	newdb.hdr.recovery = 0;
-	memset(newdb.hdr.reserved, 0, sizeof(newdb.hdr.reserved));
-	/* Initial hashes are empty. */
-	memset(newdb.hdr.hashtable, 0, sizeof(newdb.hdr.hashtable));
-
-	/* Free is empty. */
-	newdb.hdr.free_table = offsetof(struct new_database, ftable);
-	memset(&newdb.ftable, 0, sizeof(newdb.ftable));
-	ecode = set_header(NULL, &newdb.ftable.hdr, TDB_FTABLE_MAGIC, 0,
-			   sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr),
-			   sizeof(newdb.ftable) - sizeof(newdb.ftable.hdr),
-			   0);
-	if (ecode != TDB_SUCCESS) {
-		return ecode;
-	}
-
-	/* Magic food */
-	memset(newdb.hdr.magic_food, 0, sizeof(newdb.hdr.magic_food));
-	strcpy(newdb.hdr.magic_food, TDB_MAGIC_FOOD);
-
-	/* This creates an endian-converted database, as if read from disk */
-	magic_len = sizeof(newdb.hdr.magic_food);
-	tdb_convert(tdb,
-		    (char *)&newdb.hdr + magic_len, sizeof(newdb) - magic_len);
-
-	*hdr = newdb.hdr;
-
-	if (tdb->flags & TDB_INTERNAL) {
-		tdb->map_size = sizeof(newdb);
-		tdb->map_ptr = malloc(tdb->map_size);
-		if (!tdb->map_ptr) {
-			return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
-					  "tdb_new_database:"
-					  " failed to allocate");
-		}
-		memcpy(tdb->map_ptr, &newdb, tdb->map_size);
-		return TDB_SUCCESS;
-	}
-	if (lseek(tdb->fd, 0, SEEK_SET) == -1) {
-		return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-				  "tdb_new_database:"
-				  " failed to seek: %s", strerror(errno));
-	}
-
-	if (ftruncate(tdb->fd, 0) == -1) {
-		return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-				  "tdb_new_database:"
-				  " failed to truncate: %s", strerror(errno));
-	}
-
-	rlen = write(tdb->fd, &newdb, sizeof(newdb));
-	if (rlen != sizeof(newdb)) {
-		if (rlen >= 0)
-			errno = ENOSPC;
-		return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-				  "tdb_new_database: %zi writing header: %s",
-				  rlen, strerror(errno));
-	}
-	return TDB_SUCCESS;
-}
-
-struct tdb_context *tdb_open(const char *name, int tdb_flags,
-			     int open_flags, mode_t mode,
-			     union tdb_attribute *attr)
-{
-	struct tdb_context *tdb;
-	struct stat st;
-	int saved_errno = 0;
-	uint64_t hash_test;
-	unsigned v;
-	ssize_t rlen;
-	struct tdb_header hdr;
-	struct tdb_attribute_seed *seed = NULL;
-	tdb_bool_err berr;
-	enum TDB_ERROR ecode;
-
-	tdb = malloc(sizeof(*tdb));
-	if (!tdb) {
-		/* Can't log this */
-		errno = ENOMEM;
-		return NULL;
-	}
-	tdb->name = NULL;
-	tdb->map_ptr = NULL;
-	tdb->direct_access = 0;
-	tdb->fd = -1;
-	tdb->map_size = sizeof(struct tdb_header);
-	tdb->ecode = TDB_SUCCESS;
-	tdb->flags = tdb_flags;
-	tdb->logfn = NULL;
-	tdb->transaction = NULL;
-	tdb->stats = NULL;
-	tdb->access = NULL;
-	tdb_hash_init(tdb);
-	tdb_io_init(tdb);
-	tdb_lock_init(tdb);
-
-	while (attr) {
-		switch (attr->base.attr) {
-		case TDB_ATTRIBUTE_LOG:
-			tdb->logfn = attr->log.log_fn;
-			tdb->log_private = attr->log.log_private;
-			break;
-		case TDB_ATTRIBUTE_HASH:
-			tdb->khash = attr->hash.hash_fn;
-			tdb->hash_priv = attr->hash.hash_private;
-			break;
-		case TDB_ATTRIBUTE_SEED:
-			seed = &attr->seed;
-			break;
-		case TDB_ATTRIBUTE_STATS:
-			tdb->stats = &attr->stats;
-			/* They have stats we don't know about?  Tell them. */
-			if (tdb->stats->size > sizeof(attr->stats))
-				tdb->stats->size = sizeof(attr->stats);
-			break;
-		default:
-			tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
-				   "tdb_open: unknown attribute type %u",
-				   attr->base.attr);
-			goto fail;
-		}
-		attr = attr->base.next;
-	}
-
-	if ((open_flags & O_ACCMODE) == O_WRONLY) {
-		tdb_logerr(tdb, TDB_ERR_EINVAL, TDB_LOG_USE_ERROR,
-			   "tdb_open: can't open tdb %s write-only", name);
-		goto fail;
-	}
-
-	if ((open_flags & O_ACCMODE) == O_RDONLY) {
-		tdb->read_only = true;
-		/* read only databases don't do locking */
-		tdb->flags |= TDB_NOLOCK;
-		tdb->mmap_flags = PROT_READ;
-	} else {
-		tdb->read_only = false;
-		tdb->mmap_flags = PROT_READ | PROT_WRITE;
-	}
-
-	/* internal databases don't need any of the rest. */
-	if (tdb->flags & TDB_INTERNAL) {
-		tdb->flags |= (TDB_NOLOCK | TDB_NOMMAP);
-		if (tdb_new_database(tdb, seed, &hdr) != 0) {
-			goto fail;
-		}
-		tdb_convert(tdb, &hdr.hash_seed, sizeof(hdr.hash_seed));
-		tdb->hash_seed = hdr.hash_seed;
-		tdb_ftable_init(tdb);
-		return tdb;
-	}
-
-	if ((tdb->fd = open(name, open_flags, mode)) == -1) {
-		/* errno set by open(2) */
-		saved_errno = errno;
-		tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-			   "tdb_open: could not open file %s: %s",
-			   name, strerror(errno));
-		goto fail;
-	}
-
-	/* on exec, don't inherit the fd */
-	v = fcntl(tdb->fd, F_GETFD, 0);
-        fcntl(tdb->fd, F_SETFD, v | FD_CLOEXEC);
-
-	/* ensure there is only one process initialising at once */
-	tdb->ecode = tdb_lock_open(tdb, TDB_LOCK_WAIT|TDB_LOCK_NOCHECK);
-	if (tdb->ecode != TDB_SUCCESS) {
-		goto fail;
-	}
-
-	/* If they used O_TRUNC, read will return 0. */
-	rlen = read(tdb->fd, &hdr, sizeof(hdr));
-	if (rlen == 0 && (open_flags & O_CREAT)) {
-		if (tdb_new_database(tdb, seed, &hdr) == -1) {
-			goto fail;
-		}
-	} else if (rlen < 0) {
-		tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-			   "tdb_open: error %s reading %s",
-			   strerror(errno), name);
-		goto fail;
-	} else if (rlen < sizeof(hdr)
-		   || strcmp(hdr.magic_food, TDB_MAGIC_FOOD) != 0) {
-		tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-			   "tdb_open: %s is not a tdb file", name);
-		goto fail;
-	}
-
-	if (hdr.version != TDB_VERSION) {
-		if (hdr.version == bswap_64(TDB_VERSION))
-			tdb->flags |= TDB_CONVERT;
-		else {
-			/* wrong version */
-			tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-				   "tdb_open: %s is unknown version 0x%llx",
-				   name, (long long)hdr.version);
-			goto fail;
-		}
-	}
-
-	tdb_convert(tdb, &hdr, sizeof(hdr));
-	tdb->hash_seed = hdr.hash_seed;
-	hash_test = TDB_HASH_MAGIC;
-	hash_test = tdb_hash(tdb, &hash_test, sizeof(hash_test));
-	if (hdr.hash_test != hash_test) {
-		/* wrong hash variant */
-		tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-			   "tdb_open: %s uses a different hash function",
-			   name);
-		goto fail;
-	}
-
-	if (fstat(tdb->fd, &st) == -1) {
-		saved_errno = errno;
-		tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-			   "tdb_open: could not stat open %s: %s",
-			   name, strerror(errno));
-		goto fail;
-	}
-
-	/* Is it already in the open list?  If so, fail. */
-	if (tdb_already_open(st.st_dev, st.st_ino)) {
-		/* FIXME */
-		tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_USE_ERROR,
-			   "tdb_open: %s (%d,%d) is already open in this"
-			   " process",
-			   name, (int)st.st_dev, (int)st.st_ino);
-		goto fail;
-	}
-
-	tdb->name = strdup(name);
-	if (!tdb->name) {
-		tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
-			   "tdb_open: failed to allocate name");
-		goto fail;
-	}
-
-	tdb->device = st.st_dev;
-	tdb->inode = st.st_ino;
-	tdb_unlock_open(tdb);
-
-	/* This make sure we have current map_size and mmap. */
-	tdb->methods->oob(tdb, tdb->map_size + 1, true);
-
-	/* Now it's fully formed, recover if necessary. */
-	berr = tdb_needs_recovery(tdb);
-	if (unlikely(berr != false)) {
-		if (berr < 0) {
-			ecode = berr;
-			goto fail;
-		}
-		ecode = tdb_lock_and_recover(tdb);
-		if (ecode != TDB_SUCCESS) {
-			tdb->ecode = ecode;
-			goto fail;
-		}
-	}
-
-	tdb->ecode = tdb_ftable_init(tdb);
-	if (tdb->ecode != TDB_SUCCESS) {
-		goto fail;
-	}
-
-	tdb->next = tdbs;
-	tdbs = tdb;
-	return tdb;
-
- fail:
-	/* Map ecode to some logical errno. */
-	if (!saved_errno) {
-		switch (tdb->ecode) {
-		case TDB_ERR_CORRUPT:
-		case TDB_ERR_IO:
-			saved_errno = EIO;
-			break;
-		case TDB_ERR_LOCK:
-			saved_errno = EWOULDBLOCK;
-			break;
-		case TDB_ERR_OOM:
-			saved_errno = ENOMEM;
-			break;
-		case TDB_ERR_EINVAL:
-			saved_errno = EINVAL;
-			break;
-		default:
-			saved_errno = EINVAL;
-			break;
-		}
-	}
-
-#ifdef TDB_TRACE
-	close(tdb->tracefd);
-#endif
-	if (tdb->map_ptr) {
-		if (tdb->flags & TDB_INTERNAL) {
-			free(tdb->map_ptr);
-		} else
-			tdb_munmap(tdb);
-	}
-	free(tdb->lockrecs);
-	free((char *)tdb->name);
-	if (tdb->fd != -1)
-		if (close(tdb->fd) != 0)
-			tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
-				   "tdb_open: failed to close tdb->fd"
-				   " on error: %s", strerror(errno));
-	free(tdb);
-	errno = saved_errno;
-	return NULL;
-}
-
 static enum TDB_ERROR update_rec_hdr(struct tdb_context *tdb,
 				     tdb_off_t off,
 				     tdb_len_t keylen,
@@ -459,10 +55,11 @@ static enum TDB_ERROR replace_data(struct tdb_context *tdb,
 
 	/* We didn't like the existing one: remove it. */
 	if (old_off) {
-		add_stat(tdb, frees, 1);
+		tdb->stats.frees++;
 		ecode = add_free_record(tdb, old_off,
 					sizeof(struct tdb_used_record)
-					+ key.dsize + old_room);
+					+ key.dsize + old_room,
+					TDB_LOCK_WAIT, true);
 		if (ecode == TDB_SUCCESS)
 			ecode = replace_in_hash(tdb, h, new_off);
 	} else {
@@ -473,23 +70,43 @@ static enum TDB_ERROR replace_data(struct tdb_context *tdb,
 	}
 
 	new_off += sizeof(struct tdb_used_record);
-	ecode = tdb->methods->twrite(tdb, new_off, key.dptr, key.dsize);
+	ecode = tdb->tdb2.io->twrite(tdb, new_off, key.dptr, key.dsize);
 	if (ecode != TDB_SUCCESS) {
 		return ecode;
 	}
 
 	new_off += key.dsize;
-	ecode = tdb->methods->twrite(tdb, new_off, dbuf.dptr, dbuf.dsize);
+	ecode = tdb->tdb2.io->twrite(tdb, new_off, dbuf.dptr, dbuf.dsize);
 	if (ecode != TDB_SUCCESS) {
 		return ecode;
 	}
 
-	/* FIXME: tdb_increment_seqnum(tdb); */
+	if (tdb->flags & TDB_SEQNUM)
+		tdb_inc_seqnum(tdb);
+
 	return TDB_SUCCESS;
 }
 
-int tdb_store(struct tdb_context *tdb,
-	      struct tdb_data key, struct tdb_data dbuf, int flag)
+static enum TDB_ERROR update_data(struct tdb_context *tdb,
+				  tdb_off_t off,
+				  struct tdb_data dbuf,
+				  tdb_len_t extra)
+{
+	enum TDB_ERROR ecode;
+
+	ecode = tdb->tdb2.io->twrite(tdb, off, dbuf.dptr, dbuf.dsize);
+	if (ecode == TDB_SUCCESS && extra) {
+		/* Put a zero in; future versions may append other data. */
+		ecode = tdb->tdb2.io->twrite(tdb, off + dbuf.dsize, "", 1);
+	}
+	if (tdb->flags & TDB_SEQNUM)
+		tdb_inc_seqnum(tdb);
+
+	return ecode;
+}
+
+enum TDB_ERROR tdb_store(struct tdb_context *tdb,
+			 struct tdb_data key, struct tdb_data dbuf, int flag)
 {
 	struct hash_info h;
 	tdb_off_t off;
@@ -497,17 +114,22 @@ int tdb_store(struct tdb_context *tdb,
 	struct tdb_used_record rec;
 	enum TDB_ERROR ecode;
 
+	if (tdb->flags & TDB_VERSION1) {
+		if (tdb1_store(tdb, key, dbuf, flag) == -1)
+			return tdb->last_error;
+		return TDB_SUCCESS;
+	}
+
 	off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 	if (TDB_OFF_IS_ERR(off)) {
-		tdb->ecode = off;
-		return -1;
+		return tdb->last_error = off;
 	}
 
 	/* Now we have lock on this hash bucket. */
 	if (flag == TDB_INSERT) {
 		if (off) {
-			tdb->ecode = TDB_ERR_EXISTS;
-			goto fail;
+			ecode = TDB_ERR_EXISTS;
+			goto out;
 		}
 	} else {
 		if (off) {
@@ -519,49 +141,39 @@ int tdb_store(struct tdb_context *tdb,
 						       key.dsize, dbuf.dsize,
 						       &rec, h.h);
 				if (ecode != TDB_SUCCESS) {
-					tdb->ecode = ecode;
-					goto fail;
+					goto out;
 				}
-				ecode = tdb->methods->twrite(tdb,
-							     off + sizeof(rec)
-							     + key.dsize,
-							     dbuf.dptr,
-							     dbuf.dsize);
+				ecode = update_data(tdb,
+						    off + sizeof(rec)
+						    + key.dsize, dbuf,
+						    old_room - dbuf.dsize);
 				if (ecode != TDB_SUCCESS) {
-					tdb->ecode = ecode;
-					goto fail;
+					goto out;
 				}
 				tdb_unlock_hashes(tdb, h.hlock_start,
 						  h.hlock_range, F_WRLCK);
-				return 0;
+				return tdb->last_error = TDB_SUCCESS;
 			}
 		} else {
 			if (flag == TDB_MODIFY) {
 				/* if the record doesn't exist and we
 				   are in TDB_MODIFY mode then we should fail
 				   the store */
-				tdb->ecode = TDB_ERR_NOEXIST;
-				goto fail;
+				ecode = TDB_ERR_NOEXIST;
+				goto out;
 			}
 		}
 	}
 
 	/* If we didn't use the old record, this implies we're growing. */
 	ecode = replace_data(tdb, &h, key, dbuf, off, old_room, off);
+out:
 	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
-	if (ecode != TDB_SUCCESS) {
-		tdb->ecode = ecode;
-		return -1;
-	}
-	return 0;
-
-fail:
-	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
-	return -1;
+	return tdb->last_error = ecode;
 }
 
-int tdb_append(struct tdb_context *tdb,
-	       struct tdb_data key, struct tdb_data dbuf)
+enum TDB_ERROR tdb_append(struct tdb_context *tdb,
+			  struct tdb_data key, struct tdb_data dbuf)
 {
 	struct hash_info h;
 	tdb_off_t off;
@@ -573,8 +185,7 @@ int tdb_append(struct tdb_context *tdb,
 
 	off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 	if (TDB_OFF_IS_ERR(off)) {
-		tdb->ecode = off;
-		return -1;
+		return tdb->last_error = off;
 	}
 
 	if (off) {
@@ -587,38 +198,29 @@ int tdb_append(struct tdb_context *tdb,
 					       old_dlen + dbuf.dsize, &rec,
 					       h.h);
 			if (ecode != TDB_SUCCESS) {
-				tdb->ecode = ecode;
-				goto fail;
+				goto out;
 			}
 
 			off += sizeof(rec) + key.dsize + old_dlen;
-			ecode = tdb->methods->twrite(tdb, off, dbuf.dptr,
-						     dbuf.dsize);
-			if (ecode != TDB_SUCCESS) {
-				tdb->ecode = ecode;
-				goto fail;
-			}
-
-			/* FIXME: tdb_increment_seqnum(tdb); */
-			tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range,
-					  F_WRLCK);
-			return 0;
+			ecode = update_data(tdb, off, dbuf,
+					    rec_extra_padding(&rec));
+			goto out;
 		}
 
 		/* Slow path. */
 		newdata = malloc(key.dsize + old_dlen + dbuf.dsize);
 		if (!newdata) {
-			tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
-				   "tdb_append: failed to allocate %zu bytes",
-				   (size_t)(key.dsize+old_dlen+dbuf.dsize));
-			goto fail;
+			ecode = tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
+					   "tdb_append:"
+					   " failed to allocate %zu bytes",
+					   (size_t)(key.dsize + old_dlen
+						    + dbuf.dsize));
+			goto out;
 		}
-		ecode = tdb->methods->tread(tdb, off + sizeof(rec) + key.dsize,
+		ecode = tdb->tdb2.io->tread(tdb, off + sizeof(rec) + key.dsize,
 					    newdata, old_dlen);
 		if (ecode != TDB_SUCCESS) {
-			tdb->ecode = ecode;
-			free(newdata);
-			goto fail;
+			goto out_free_newdata;
 		}
 		memcpy(newdata + old_dlen, dbuf.dptr, dbuf.dsize);
 		new_dbuf.dptr = newdata;
@@ -630,51 +232,61 @@ int tdb_append(struct tdb_context *tdb,
 
 	/* If they're using tdb_append(), it implies they're growing record. */
 	ecode = replace_data(tdb, &h, key, new_dbuf, off, old_room, true);
-	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
-	free(newdata);
 
-	if (ecode != TDB_SUCCESS) {
-		tdb->ecode = ecode;
-		return -1;
-	}
-	return 0;
-
-fail:
+out_free_newdata:
+	free(newdata);
+out:
 	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
-	return -1;
+	return tdb->last_error = ecode;
 }
 
-struct tdb_data tdb_fetch(struct tdb_context *tdb, struct tdb_data key)
+enum TDB_ERROR tdb_fetch(struct tdb_context *tdb, struct tdb_data key,
+			 struct tdb_data *data)
 {
 	tdb_off_t off;
 	struct tdb_used_record rec;
 	struct hash_info h;
-	struct tdb_data ret;
+	enum TDB_ERROR ecode;
 
 	off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
 	if (TDB_OFF_IS_ERR(off)) {
-		tdb->ecode = off;
-		return tdb_null;
+		return tdb->last_error = off;
 	}
 
 	if (!off) {
-		tdb->ecode = TDB_ERR_NOEXIST;
-		ret = tdb_null;
+		ecode = TDB_ERR_NOEXIST;
 	} else {
-		ret.dsize = rec_data_length(&rec);
-		ret.dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
-					  ret.dsize);
-		if (TDB_PTR_IS_ERR(ret.dptr)) {
-			tdb->ecode = TDB_PTR_ERR(ret.dptr);
-			ret = tdb_null;
-		}
+		data->dsize = rec_data_length(&rec);
+		data->dptr = tdb_alloc_read(tdb, off + sizeof(rec) + key.dsize,
+					    data->dsize);
+		if (TDB_PTR_IS_ERR(data->dptr)) {
+			ecode = TDB_PTR_ERR(data->dptr);
+		} else
+			ecode = TDB_SUCCESS;
 	}
 
 	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
-	return ret;
+	return tdb->last_error = ecode;
+}
+
+bool tdb_exists(struct tdb_context *tdb, TDB_DATA key)
+{
+	tdb_off_t off;
+	struct tdb_used_record rec;
+	struct hash_info h;
+
+	off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
+	if (TDB_OFF_IS_ERR(off)) {
+		tdb->last_error = off;
+		return false;
+	}
+	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
+
+	tdb->last_error = TDB_SUCCESS;
+	return off ? true : false;
 }
 
-int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
+enum TDB_ERROR tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 {
 	tdb_off_t off;
 	struct tdb_used_record rec;
@@ -683,91 +295,158 @@ int tdb_delete(struct tdb_context *tdb, struct tdb_data key)
 
 	off = find_and_lock(tdb, key, F_WRLCK, &h, &rec, NULL);
 	if (TDB_OFF_IS_ERR(off)) {
-		tdb->ecode = off;
-		return -1;
+		return tdb->last_error = off;
 	}
 
 	if (!off) {
-		tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
-		tdb->ecode = TDB_ERR_NOEXIST;
-		return -1;
+		ecode = TDB_ERR_NOEXIST;
+		goto unlock;
 	}
 
 	ecode = delete_from_hash(tdb, &h);
 	if (ecode != TDB_SUCCESS) {
-		tdb->ecode = ecode;
-		goto unlock_err;
+		goto unlock;
 	}
 
 	/* Free the deleted entry. */
-	add_stat(tdb, frees, 1);
+	tdb->stats.frees++;
 	ecode = add_free_record(tdb, off,
 				sizeof(struct tdb_used_record)
 				+ rec_key_length(&rec)
 				+ rec_data_length(&rec)
-				+ rec_extra_padding(&rec));
-	if (ecode != TDB_SUCCESS) {
-		tdb->ecode = ecode;
-		goto unlock_err;
-	}
+				+ rec_extra_padding(&rec),
+				TDB_LOCK_WAIT, true);
 
-	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
-	return 0;
+	if (tdb->flags & TDB_SEQNUM)
+		tdb_inc_seqnum(tdb);
 
-unlock_err:
+unlock:
 	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_WRLCK);
-	return -1;
+	return tdb->last_error = ecode;
 }
 
-int tdb_close(struct tdb_context *tdb)
+unsigned int tdb_get_flags(struct tdb_context *tdb)
 {
-	struct tdb_context **i;
-	int ret = 0;
+	return tdb->flags;
+}
 
-	tdb_trace(tdb, "tdb_close");
+static bool inside_transaction(const struct tdb_context *tdb)
+{
+	if (tdb->flags & TDB_VERSION1)
+		return tdb->tdb1.transaction != NULL;
+	else
+		return tdb->tdb2.transaction != NULL;
+}
 
-	if (tdb->transaction) {
-		tdb_transaction_cancel(tdb);
+static bool readonly_changable(struct tdb_context *tdb, const char *caller)
+{
+	if (inside_transaction(tdb)) {
+		tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+					     TDB_LOG_USE_ERROR,
+					     "%s: can't change"
+					     " TDB_RDONLY inside transaction",
+					     caller);
+		return false;
+	}
+
+	if (tdb->file->allrecord_lock.count != 0
+	    || tdb->file->num_lockrecs != 0) {
+		tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+					     TDB_LOG_USE_ERROR,
+					     "%s: can't change"
+					     " TDB_RDONLY holding locks",
+					     caller);
+		return false;
 	}
+	return true;
+}
 
-	if (tdb->map_ptr) {
-		if (tdb->flags & TDB_INTERNAL)
-			free(tdb->map_ptr);
-		else
-			tdb_munmap(tdb);
+void tdb_add_flag(struct tdb_context *tdb, unsigned flag)
+{
+	if (tdb->flags & TDB_INTERNAL) {
+		tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+					     TDB_LOG_USE_ERROR,
+					     "tdb_add_flag: internal db");
+		return;
 	}
-	free((char *)tdb->name);
-	if (tdb->fd != -1) {
-		ret = close(tdb->fd);
-		tdb->fd = -1;
+	switch (flag) {
+	case TDB_NOLOCK:
+		tdb->flags |= TDB_NOLOCK;
+		break;
+	case TDB_NOMMAP:
+		tdb->flags |= TDB_NOMMAP;
+		tdb_munmap(tdb->file);
+		break;
+	case TDB_NOSYNC:
+		tdb->flags |= TDB_NOSYNC;
+		break;
+	case TDB_SEQNUM:
+		tdb->flags |= TDB_SEQNUM;
+		break;
+	case TDB_ALLOW_NESTING:
+		tdb->flags |= TDB_ALLOW_NESTING;
+		break;
+	case TDB_RDONLY:
+		if (readonly_changable(tdb, "tdb_add_flag"))
+			tdb->flags |= TDB_RDONLY;
+		break;
+	default:
+		tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+					     TDB_LOG_USE_ERROR,
+					     "tdb_add_flag: Unknown flag %u",
+					     flag);
 	}
-	free(tdb->lockrecs);
+}
 
-	/* Remove from contexts list */
-	for (i = &tdbs; *i; i = &(*i)->next) {
-		if (*i == tdb) {
-			*i = tdb->next;
+void tdb_remove_flag(struct tdb_context *tdb, unsigned flag)
+{
+	if (tdb->flags & TDB_INTERNAL) {
+		tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+					     TDB_LOG_USE_ERROR,
+					     "tdb_remove_flag: internal db");
+		return;
+	}
+	switch (flag) {
+	case TDB_NOLOCK:
+		tdb->flags &= ~TDB_NOLOCK;
+		break;
+	case TDB_NOMMAP:
+		tdb->flags &= ~TDB_NOMMAP;
+		tdb_mmap(tdb);
+		break;
+	case TDB_NOSYNC:
+		tdb->flags &= ~TDB_NOSYNC;
+		break;
+	case TDB_SEQNUM:
+		tdb->flags &= ~TDB_SEQNUM;
+		break;
+	case TDB_ALLOW_NESTING:
+		tdb->flags &= ~TDB_ALLOW_NESTING;
+		break;
+	case TDB_RDONLY:
+		if ((tdb->open_flags & O_ACCMODE) == O_RDONLY) {
+			tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+						     TDB_LOG_USE_ERROR,
+						     "tdb_remove_flag: can't"
+						     " remove TDB_RDONLY on tdb"
+						     " opened with O_RDONLY");
 			break;
 		}
+		if (readonly_changable(tdb, "tdb_remove_flag"))
+			tdb->flags &= ~TDB_RDONLY;
+		break;
+	default:
+		tdb->last_error = tdb_logerr(tdb, TDB_ERR_EINVAL,
+					     TDB_LOG_USE_ERROR,
+					     "tdb_remove_flag: Unknown flag %u",
+					     flag);
 	}
-
-#ifdef TDB_TRACE
-	close(tdb->tracefd);
-#endif
-	free(tdb);
-
-	return ret;
-}
-
-enum TDB_ERROR tdb_error(const struct tdb_context *tdb)
-{
-	return tdb->ecode;
 }
 
-const char *tdb_errorstr(const struct tdb_context *tdb)
+const char *tdb_errorstr(enum TDB_ERROR ecode)
 {
 	/* Gcc warns if you miss a case in the switch, so use that. */
-	switch (tdb->ecode) {
+	switch (ecode) {
 	case TDB_SUCCESS: return "Success";
 	case TDB_ERR_CORRUPT: return "Corrupt database";
 	case TDB_ERR_IO: return "IO Error";
@@ -781,6 +460,11 @@ const char *tdb_errorstr(const struct tdb_context *tdb)
 	return "Invalid error code";
 }
 
+enum TDB_ERROR tdb_error(struct tdb_context *tdb)
+{
+	return tdb->last_error;
+}
+
 enum TDB_ERROR COLD tdb_logerr(struct tdb_context *tdb,
 			       enum TDB_ERROR ecode,
 			       enum tdb_log_level level,
@@ -792,28 +476,79 @@ enum TDB_ERROR COLD tdb_logerr(struct tdb_context *tdb,
 	/* tdb_open paths care about errno, so save it. */
 	int saved_errno = errno;
 
-	tdb->ecode = ecode;
-
-	if (!tdb->logfn)
+	if (!tdb->log_fn)
 		return ecode;
 
-	/* FIXME: Doesn't assume asprintf. */
 	va_start(ap, fmt);
-	len = vsnprintf(NULL, 0, fmt, ap);
+	len = vasprintf(&message, fmt, ap);
 	va_end(ap);
 
-	message = malloc(len + 1);
-	if (!message) {
-		tdb->logfn(tdb, TDB_LOG_ERROR, tdb->log_private,
-			   "out of memory formatting message:");
-		tdb->logfn(tdb, level, tdb->log_private, fmt);
-		return ecode;
+	if (len < 0) {
+		tdb->log_fn(tdb, TDB_LOG_ERROR, TDB_ERR_OOM,
+			    "out of memory formatting message:", tdb->log_data);
+		tdb->log_fn(tdb, level, ecode, fmt, tdb->log_data);
+	} else {
+		tdb->log_fn(tdb, level, ecode, message, tdb->log_data);
+		free(message);
 	}
-	va_start(ap, fmt);
-	len = vsprintf(message, fmt, ap);
-	va_end(ap);
-	tdb->logfn(tdb, level, tdb->log_private, message);
-	free(message);
 	errno = saved_errno;
 	return ecode;
 }
+
+enum TDB_ERROR tdb_parse_record_(struct tdb_context *tdb,
+				 TDB_DATA key,
+				 enum TDB_ERROR (*parse)(TDB_DATA k,
+							 TDB_DATA d,
+							 void *data),
+				 void *data)
+{
+	tdb_off_t off;
+	struct tdb_used_record rec;
+	struct hash_info h;
+	enum TDB_ERROR ecode;
+
+	off = find_and_lock(tdb, key, F_RDLCK, &h, &rec, NULL);
+	if (TDB_OFF_IS_ERR(off)) {
+		return tdb->last_error = off;
+	}
+
+	if (!off) {
+		ecode = TDB_ERR_NOEXIST;
+	} else {
+		const void *dptr;
+		dptr = tdb_access_read(tdb, off + sizeof(rec) + key.dsize,
+				       rec_data_length(&rec), false);
+		if (TDB_PTR_IS_ERR(dptr)) {
+			ecode = TDB_PTR_ERR(dptr);
+		} else {
+			TDB_DATA d = tdb_mkdata(dptr, rec_data_length(&rec));
+
+			ecode = parse(key, d, data);
+			tdb_access_release(tdb, dptr);
+		}
+	}
+
+	tdb_unlock_hashes(tdb, h.hlock_start, h.hlock_range, F_RDLCK);
+	return tdb->last_error = ecode;
+}
+
+const char *tdb_name(const struct tdb_context *tdb)
+{
+	return tdb->name;
+}
+
+int64_t tdb_get_seqnum(struct tdb_context *tdb)
+{
+	tdb_off_t off = tdb_read_off(tdb, offsetof(struct tdb_header, seqnum));
+	if (TDB_OFF_IS_ERR(off))
+		tdb->last_error = off;
+	else
+		tdb->last_error = TDB_SUCCESS;
+	return off;
+}
+	
+
+int tdb_fd(const struct tdb_context *tdb)
+{
+	return tdb->file->fd;
+}