From 294ccfd46a0c4e1af9365d028acdabec03c41ad3 Mon Sep 17 00:00:00 2001
From: Andrew Tridgell <tridge@samba.org>
Date: Sat, 24 Sep 2005 03:43:02 +0000
Subject: [PATCH] r10465: separate out a read_only db from a read-only
 traversal to ensure we don't end up doing a mmap read only

---
 source/lib/tdb/common/io.c          |  4 ++--
 source/lib/tdb/common/lock.c        |  4 ++--
 source/lib/tdb/common/tdb.c         |  4 ++--
 source/lib/tdb/common/tdb_private.h |  1 +
 source/lib/tdb/common/transaction.c |  2 +-
 source/lib/tdb/common/traverse.c    | 10 +++++-----
 6 files changed, 13 insertions(+), 12 deletions(-)

diff --git a/source/lib/tdb/common/io.c b/source/lib/tdb/common/io.c
index c1f6f55bc48..a276a8c291a 100644
--- a/source/lib/tdb/common/io.c
+++ b/source/lib/tdb/common/io.c
@@ -97,7 +97,7 @@ static int tdb_oob(struct tdb_context *tdb, tdb_off_t len, int probe)
 static int tdb_write(struct tdb_context *tdb, tdb_off_t off, 
 		     const void *buf, tdb_len_t len)
 {
-	if (tdb->read_only) {
+	if (tdb->read_only || tdb->traverse_read) {
 		tdb->ecode = TDB_ERR_RDONLY;
 		return -1;
 	}
@@ -230,7 +230,7 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_off_t size, tdb_off_t ad
 {
 	char buf[1024];
 
-	if (tdb->read_only) {
+	if (tdb->read_only || tdb->traverse_read) {
 		tdb->ecode = TDB_ERR_RDONLY;
 		return -1;
 	}
diff --git a/source/lib/tdb/common/lock.c b/source/lib/tdb/common/lock.c
index 7a76bd3d9b3..703cfe9dc5f 100644
--- a/source/lib/tdb/common/lock.c
+++ b/source/lib/tdb/common/lock.c
@@ -46,7 +46,7 @@ int tdb_brlock_len(struct tdb_context *tdb, tdb_off_t offset,
 		return 0;
 	}
 
-	if ((rw_type == F_WRLCK) && (tdb->read_only)) {
+	if ((rw_type == F_WRLCK) && (tdb->read_only || tdb->traverse_read)) {
 		tdb->ecode = TDB_ERR_RDONLY;
 		return -1;
 	}
@@ -161,7 +161,7 @@ int tdb_lockall(struct tdb_context *tdb)
 	u32 i;
 
 	/* There are no locks on read-only dbs */
-	if (tdb->read_only)
+	if (tdb->read_only || tdb->traverse_read)
 		return TDB_ERRCODE(TDB_ERR_LOCK, -1);
 	for (i = 0; i < tdb->header.hash_size; i++) 
 		if (tdb_lock(tdb, i, F_WRLCK))
diff --git a/source/lib/tdb/common/tdb.c b/source/lib/tdb/common/tdb.c
index 2e229e88ccb..4b0d4a31c5d 100644
--- a/source/lib/tdb/common/tdb.c
+++ b/source/lib/tdb/common/tdb.c
@@ -164,7 +164,7 @@ int tdb_do_delete(struct tdb_context *tdb, tdb_off_t rec_ptr, struct list_struct
 	tdb_off_t last_ptr, i;
 	struct list_struct lastrec;
 
-	if (tdb->read_only) return -1;
+	if (tdb->read_only || tdb->traverse_read) return -1;
 
 	if (tdb_write_lock_record(tdb, rec_ptr) == -1) {
 		/* Someone traversing here: mark it as dead */
@@ -227,7 +227,7 @@ int tdb_store(struct tdb_context *tdb, TDB_DATA key, TDB_DATA dbuf, int flag)
 	char *p = NULL;
 	int ret = 0;
 
-	if (tdb->read_only) {
+	if (tdb->read_only || tdb->traverse_read) {
 		tdb->ecode = TDB_ERR_RDONLY;
 		return -1;
 	}
diff --git a/source/lib/tdb/common/tdb_private.h b/source/lib/tdb/common/tdb_private.h
index 9eeaea4cb08..2b2d6de4112 100644
--- a/source/lib/tdb/common/tdb_private.h
+++ b/source/lib/tdb/common/tdb_private.h
@@ -183,6 +183,7 @@ struct tdb_context {
 	int fd; /* open file descriptor for the database */
 	tdb_len_t map_size; /* how much space has been mapped */
 	int read_only; /* opened read-only */
+	int traverse_read; /* read-only traversal */
 	struct tdb_lock_type *locked; /* array of chain locks */
 	enum TDB_ERROR ecode; /* error code for last tdb error */
 	struct tdb_header header; /* a cached copy of the header */
diff --git a/source/lib/tdb/common/transaction.c b/source/lib/tdb/common/transaction.c
index 5f281ca4daf..a01f8307e9d 100644
--- a/source/lib/tdb/common/transaction.c
+++ b/source/lib/tdb/common/transaction.c
@@ -349,7 +349,7 @@ static const struct tdb_methods transaction_methods = {
 int tdb_transaction_start(struct tdb_context *tdb)
 {
 	/* some sanity checks */
-	if (tdb->read_only || (tdb->flags & TDB_INTERNAL)) {
+	if (tdb->read_only || (tdb->flags & TDB_INTERNAL) || tdb->traverse_read) {
 		TDB_LOG((tdb, 0, "tdb_transaction_start: cannot start a transaction on a read-only or internal db\n"));
 		tdb->ecode = TDB_ERR_EINVAL;
 		return -1;
diff --git a/source/lib/tdb/common/traverse.c b/source/lib/tdb/common/traverse.c
index f8315f5770e..9271b75aa81 100644
--- a/source/lib/tdb/common/traverse.c
+++ b/source/lib/tdb/common/traverse.c
@@ -114,7 +114,7 @@ static int tdb_next_lock(struct tdb_context *tdb, struct tdb_traverse_lock *tloc
 			/* Try to clean dead ones from old traverses */
 			current = tlock->off;
 			tlock->off = rec->next;
-			if (!tdb->read_only && 
+			if (!(tdb->read_only || tdb->traverse_read) && 
 			    tdb_do_delete(tdb, current, rec) != 0)
 				goto fail;
 		}
@@ -204,10 +204,10 @@ int tdb_traverse_read(struct tdb_context *tdb,
 		      tdb_traverse_func fn, void *private)
 {
 	struct tdb_traverse_lock tl = { NULL, 0, 0, F_RDLCK };
-	int ret, read_only = tdb->read_only;
-	tdb->read_only = 1;
+	int ret;
+	tdb->traverse_read++;
 	ret = tdb_traverse_internal(tdb, fn, private, &tl);
-	tdb->read_only = read_only;
+	tdb->traverse_read--;
 	return ret;
 }
 
@@ -221,7 +221,7 @@ int tdb_traverse(struct tdb_context *tdb,
 	struct tdb_traverse_lock tl = { NULL, 0, 0, F_WRLCK };
 	int ret;
 
-	if (tdb->read_only) {
+	if (tdb->read_only || tdb->traverse_read) {
 		return tdb_traverse_read(tdb, fn, private);
 	}
 	
-- 
2.34.1