dbwrap_local_open: open NTDB if extension is .ntdb

This switches dbwrap_local_open() based on the extension of the
database name, so it handles both TDB and NTDB files.

Moreover, if asked to open a .ntdb, and there's no ntdb file but
there's a .tdb file, it converts that then moves it to .tdb.bak before
opening, and turn the .tdb file into a dangling symlink to make sure
it's never accidentally re-created or used:

	$ ls -l secrets.tdb 
	lrwxrwxrwx 1 rusty rusty 23 Feb 11 11:31 secrets.tdb -> This is now in an NTDB

This provides transparent upgrade if people decide to use NTDB on a
database.  Downgrade would be manual, eg:

	ntdbdump foo.ntdb | tdbrestore foo.tdb && mv foo.ntdb foo.ntdb.bak

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Reviewed-by: Andrew Bartlett <abartlet@samba.org>

1 files changed, 157 insertions, 5 deletions

diff --git a/lib/dbwrap/dbwrap_local_open.c b/lib/dbwrap/dbwrap_local_open.c
index fb5f17ebab..87c7c68418 100644
--- a/lib/dbwrap/dbwrap_local_open.c
+++ b/lib/dbwrap/dbwrap_local_open.c
@@ -21,6 +21,7 @@
 #include "includes.h"
 #include "dbwrap/dbwrap.h"
 #include "dbwrap/dbwrap_tdb.h"
+#include "dbwrap/dbwrap_ntdb.h"
 #include "tdb.h"
 #ifndef DISABLE_NTDB
 #include "lib/util/util_ntdb.h"
@@ -29,6 +30,135 @@
 #include "system/filesys.h"
 #include "ccan/str/str.h"
 
+#ifndef DISABLE_NTDB
+struct flag_map {
+	int tdb_flag;
+	int ntdb_flag;
+};
+
+static const struct flag_map tdb_ntdb_flags[] = {
+	{ TDB_CLEAR_IF_FIRST, NTDB_CLEAR_IF_FIRST },
+	{ TDB_INTERNAL, NTDB_INTERNAL },
+	{ TDB_NOLOCK, NTDB_NOLOCK },
+	{ TDB_NOMMAP, NTDB_NOMMAP },
+	{ TDB_CONVERT, NTDB_CONVERT },
+	{ TDB_NOSYNC, NTDB_NOSYNC },
+	{ TDB_SEQNUM, NTDB_SEQNUM },
+	{ TDB_VOLATILE, 0 },
+	{ TDB_ALLOW_NESTING, NTDB_ALLOW_NESTING },
+	{ TDB_DISALLOW_NESTING, 0 },
+	{ TDB_INCOMPATIBLE_HASH, 0 }
+};
+
+static int tdb_flags_to_ntdb_flags(int tdb_flags)
+{
+	unsigned int i;
+	int ntdb_flags = 0;
+
+	/* TDB allows nesting unless told not to. */
+	if (!(tdb_flags & TDB_DISALLOW_NESTING))
+		ntdb_flags |= NTDB_ALLOW_NESTING;
+
+	for (i = 0; i < sizeof(tdb_ntdb_flags)/sizeof(tdb_ntdb_flags[0]); i++) {
+		if (tdb_flags & tdb_ntdb_flags[i].tdb_flag) {
+			tdb_flags &= ~tdb_ntdb_flags[i].tdb_flag;
+			ntdb_flags |= tdb_ntdb_flags[i].ntdb_flag;
+		}
+	}
+
+	SMB_ASSERT(tdb_flags == 0);
+	return ntdb_flags;
+}
+
+struct trav_data {
+	struct db_context *ntdb;
+	NTSTATUS status;
+};
+
+static int write_to_ntdb(struct db_record *rec, void *_tdata)
+{
+	struct trav_data *tdata = _tdata;
+	TDB_DATA key, value;
+
+	key = dbwrap_record_get_key(rec);
+	value = dbwrap_record_get_value(rec);
+
+	tdata->status = dbwrap_store(tdata->ntdb, key, value, TDB_INSERT);
+	if (!NT_STATUS_IS_OK(tdata->status)) {
+		return 1;
+	}
+	return 0;
+}
+
+static bool tdb_to_ntdb(TALLOC_CTX *ctx, struct loadparm_context *lp_ctx,
+			const char *tdbname, const char *ntdbname)
+{
+	struct db_context *ntdb, *tdb;
+	char *bakname;
+	const char *tdbbase, *bakbase;
+	struct trav_data tdata;
+	struct stat st;
+
+	/* We need permissions from the tdb file. */
+	if (stat(tdbname, &st) == -1) {
+		DEBUG(0, ("tdb_to_ntdb: fstat %s failed: %s\n",
+			  tdbname, strerror(errno)));
+		return false;
+	}
+	tdb = db_open_tdb(ctx, lp_ctx, tdbname, 0,
+			  TDB_DEFAULT, O_RDONLY, 0, 0);
+	if (!tdb) {
+		DEBUG(0, ("tdb_to_ntdb: could not open %s: %s\n",
+			  tdbname, strerror(errno)));
+		return false;
+	}
+	ntdb = db_open_ntdb(ctx, lp_ctx, ntdbname, dbwrap_hash_size(tdb),
+			    TDB_DEFAULT, O_RDWR|O_CREAT|O_EXCL,
+			    st.st_mode & 0777, 0);
+	if (!ntdb) {
+		DEBUG(0, ("tdb_to_ntdb: could not create %s: %s\n",
+			  ntdbname, strerror(errno)));
+		return false;
+	}
+	bakname = talloc_asprintf(ctx, "%s.bak", tdbname);
+	if (!bakname) {
+		DEBUG(0, ("tdb_to_ntdb: could not allocate\n"));
+		return false;
+	}
+
+	tdata.status = NT_STATUS_OK;
+	tdata.ntdb = ntdb;
+	if (!NT_STATUS_IS_OK(dbwrap_traverse_read(tdb, write_to_ntdb, &tdata,
+						  NULL))) {
+		return false;
+	}
+	if (!NT_STATUS_IS_OK(tdata.status)) {
+		return false;
+	}
+
+	if (rename(tdbname, bakname) != 0) {
+		DEBUG(0, ("tdb_to_ntdb: could not rename %s to %s\n",
+			  tdbname, bakname));
+		unlink(ntdbname);
+		return false;
+	}
+
+	/* Make sure it's never accidentally used. */
+	symlink("This is now in an NTDB", tdbname);
+
+	/* Make message a bit shorter by using basenames. */
+	tdbbase = strrchr(tdbname, '/');
+	if (!tdbbase)
+		tdbbase = tdbname;
+	bakbase = strrchr(bakname, '/');
+	if (!bakbase)
+		bakbase = bakname;
+	DEBUG(1, ("Upgraded %s from %s (which moved to %s)\n",
+		  ntdbname, tdbbase, bakbase));
+	return true;
+}
+#endif /* !DISABLE_NTDB */
+
 struct db_context *dbwrap_local_open(TALLOC_CTX *mem_ctx,
 				     struct loadparm_context *lp_ctx,
 				     const char *name,
@@ -54,7 +184,10 @@ struct db_context *dbwrap_local_open(TALLOC_CTX *mem_ctx,
 					  "%.*s.tdb",
 					  (int)strlen(name) - 5, name);
 	} else {
-		ntdbname = tdbname = name;
+		DEBUG(1, ("WARNING: database '%s' does not end in .[n]tdb:"
+			  " treating it as a TDB file!\n", name));
+		ntdbname = talloc_strdup(tmp_ctx, name);
+		tdbname = name;
 	}
 
 	if (ntdbname == NULL || tdbname == NULL) {
@@ -62,10 +195,29 @@ struct db_context *dbwrap_local_open(TALLOC_CTX *mem_ctx,
 		goto out;
 	}
 
-	/* We currently always open a tdb, not an ntdb. */
-	db = db_open_tdb(mem_ctx, lp_ctx, tdbname, hash_size,
-			 tdb_flags, open_flags, mode,
-			 lock_order);
+	if (name == ntdbname) {
+#ifdef DISABLE_NTDB
+		DEBUG(1, ("WARNING: no ntdb support to open '%s'\n", name));
+#else
+		int ntdb_flags = tdb_flags_to_ntdb_flags(tdb_flags);
+
+		/* For non-internal databases, we upgrade on demand. */
+		if (!(tdb_flags & TDB_INTERNAL)) {
+			if (!file_exist(ntdbname) && file_exist(tdbname)) {
+				if (!tdb_to_ntdb(tmp_ctx, lp_ctx,
+						 tdbname, ntdbname)) {
+					goto out;
+				}
+			}
+		}
+		db = db_open_ntdb(mem_ctx, lp_ctx, ntdbname, hash_size,
+				  ntdb_flags, open_flags, mode, lock_order);
+#endif
+	} else {
+		db = db_open_tdb(mem_ctx, lp_ctx, tdbname, hash_size,
+				 tdb_flags, open_flags, mode,
+				 lock_order);
+	}
 out:
 	talloc_free(tmp_ctx);
 	return db;