wallet: Fix backupwallet for multiwallets

backupwallet was broken for multiwallets in their own directories
(i.e. something like DATADIR/wallets/mywallet/wallet.dat).  In this
case, the backup would use DATADIR/wallets/wallet.dat as source file
and not take the specific wallet's directory into account.

This led to either an error during the backup (if the wrong source
file was not present) or would silently back up the wrong wallet;
especially the latter behaviour can be quite bad for users.

2 files changed, 33 insertions, 5 deletions

diff --git a/src/wallet/db.cpp b/src/wallet/db.cpp
index 01b8eacccb..00964b8cc8 100644
--- a/src/wallet/db.cpp
+++ b/src/wallet/db.cpp
@@ -768,7 +768,7 @@ bool BerkeleyDatabase::Backup(const std::string& strDest)
                 env->mapFileUseCount.erase(strFile);
 
                 // Copy wallet file
-                fs::path pathSrc = GetWalletDir() / strFile;
+                fs::path pathSrc = env->Directory() / strFile;
                 fs::path pathDest(strDest);
                 if (fs::is_directory(pathDest))
                     pathDest /= strFile;
diff --git a/test/functional/wallet_multiwallet.py b/test/functional/wallet_multiwallet.py
index fa5a2154a4..e2938dba3b 100755
--- a/test/functional/wallet_multiwallet.py
+++ b/test/functional/wallet_multiwallet.py
@@ -30,6 +30,11 @@ class MultiWalletTest(BitcoinTestFramework):
         wallet_dir = lambda *p: data_dir('wallets', *p)
         wallet = lambda name: node.get_wallet_rpc(name)
 
+        def wallet_file(name):
+            if os.path.isdir(wallet_dir(name)):
+                return wallet_dir(name, "wallet.dat")
+            return wallet_dir(name)
+
         # check wallet.dat is created
         self.stop_nodes()
         assert_equal(os.path.isfile(wallet_dir('wallet.dat')), True)
@@ -43,6 +48,12 @@ class MultiWalletTest(BitcoinTestFramework):
         # directory paths) can be loaded
         os.rename(wallet_dir("wallet.dat"), wallet_dir("w8"))
 
+        # create another dummy wallet for use in testing backups later
+        self.start_node(0, [])
+        self.stop_nodes()
+        empty_wallet = os.path.join(self.options.tmpdir, 'empty.dat')
+        os.rename(wallet_dir("wallet.dat"), empty_wallet)
+
         # restart node with a mix of wallet names:
         #   w1, w2, w3 - to verify new wallets created when non-existing paths specified
         #   w          - to verify wallet name matching works when one wallet path is prefix of another
@@ -59,10 +70,7 @@ class MultiWalletTest(BitcoinTestFramework):
         # check that all requested wallets were created
         self.stop_node(0)
         for wallet_name in wallet_names:
-            if os.path.isdir(wallet_dir(wallet_name)):
-                assert_equal(os.path.isfile(wallet_dir(wallet_name, "wallet.dat")), True)
-            else:
-                assert_equal(os.path.isfile(wallet_dir(wallet_name)), True)
+            assert_equal(os.path.isfile(wallet_file(wallet_name)), True)
 
         # should not initialize if wallet path can't be created
         exp_stderr = "boost::filesystem::create_directory: (The system cannot find the path specified|Not a directory):"
@@ -265,5 +273,25 @@ class MultiWalletTest(BitcoinTestFramework):
         assert_equal(self.nodes[0].listwallets(), ['w1'])
         assert_equal(w1.getwalletinfo()['walletname'], 'w1')
 
+        # Test backing up and restoring wallets
+        self.log.info("Test wallet backup")
+        self.restart_node(0, ['-nowallet'])
+        for wallet_name in wallet_names:
+            self.nodes[0].loadwallet(wallet_name)
+        for wallet_name in wallet_names:
+            rpc = self.nodes[0].get_wallet_rpc(wallet_name)
+            addr = rpc.getnewaddress()
+            backup = os.path.join(self.options.tmpdir, 'backup.dat')
+            rpc.backupwallet(backup)
+            self.nodes[0].unloadwallet(wallet_name)
+            shutil.copyfile(empty_wallet, wallet_file(wallet_name))
+            self.nodes[0].loadwallet(wallet_name)
+            assert_equal(rpc.getaddressinfo(addr)['ismine'], False)
+            self.nodes[0].unloadwallet(wallet_name)
+            shutil.copyfile(backup, wallet_file(wallet_name))
+            self.nodes[0].loadwallet(wallet_name)
+            assert_equal(rpc.getaddressinfo(addr)['ismine'], True)
+
+
 if __name__ == '__main__':
     MultiWalletTest().main()