Merge bitcoin#14291: wallet: Add ListWalletDir utility function

d56a068 docs: Add release notes for listwalletdir RPC (João Barbosa)
0cb3cad qa: Add tests for listwalletdir RPC (João Barbosa)
cc33773 rpc: Add listwalletdir RPC (João Barbosa)
d1b03b8 interfaces: Add getWalletDir and listWalletDir to Node (João Barbosa)
fc4db35 wallet: Add ListWalletDir utility (João Barbosa)

Pull request description:

  `ListWalletDir` returns all available wallets in the current wallet
directory.

  Based on MeshCollider work in pull bitcoin#11485.

Tree-SHA512: 5843e3dbd1e0449f55bb8ea7c241a536078ff6ffcaad88ce5fcf8963971d48c78600fbc4f44919523b8a92329d5d8a5f567a3e0ccb0270fdd27366e19603a716

src/dummywallet.cpp

@@ -48,6 +48,16 @@ void DummyWalletInit::AddWalletOptions() const
 
 const WalletInitInterface& g_wallet_init_interface = DummyWalletInit();
 
+fs::path GetWalletDir()
+{
+    throw std::logic_error("Wallet function called in non-wallet build.");
+}
+
+std::vector<fs::path> ListWalletDir()
+{
+    throw std::logic_error("Wallet function called in non-wallet build.");
+}
+
 std::vector<std::shared_ptr<CWallet>> GetWallets()
 {
     throw std::logic_error("Wallet function called in non-wallet build.");

src/interfaces/node.cpp

@@ -45,6 +45,8 @@
 #include <univalue.h>
 
 class CWallet;
+fs::path GetWalletDir();
+std::vector<fs::path> ListWalletDir();
 std::vector<std::shared_ptr<CWallet>> GetWallets();
 
 namespace interfaces {
@@ -350,6 +352,18 @@ class NodeImpl : public Node
         LOCK(::cs_main);
         return ::pcoinsTip->GetCoin(output, coin);
     }
+    std::string getWalletDir() override
+    {
+        return GetWalletDir().string();
+    }
+    std::vector<std::string> listWalletDir() override
+    {
+        std::vector<std::string> paths;
+        for (auto& path : ListWalletDir()) {
+            paths.push_back(path.string());
+        }
+        return paths;
+    }
     std::vector<std::unique_ptr<Wallet>> getWallets() override
     {
         std::vector<std::unique_ptr<Wallet>> wallets;

src/interfaces/node.h

@@ -238,6 +238,12 @@ class Node
     //! Get unspent outputs associated with a transaction.
     virtual bool getUnspentOutput(const COutPoint& output, Coin& coin) = 0;
 
+    //! Return default wallet directory.
+    virtual std::string getWalletDir() = 0;
+
+    //! Return available wallets in wallet directory.
+    virtual std::vector<std::string> listWalletDir() = 0;
+
     //! Return interfaces for accessing wallets (if any).
     virtual std::vector<std::unique_ptr<Wallet>> getWallets() = 0;
 

src/wallet/rpcwallet.cpp

@@ -3125,6 +3125,38 @@ static UniValue getwalletinfo(const JSONRPCRequest& request)
     return obj;
 }
 
+static UniValue listwalletdir(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.size() != 0) {
+        throw std::runtime_error(
+            "listwalletdir\n"
+            "Returns a list of wallets in the wallet directory.\n"
+            "{\n"
+            "  \"wallets\" : [                (json array of objects)\n"
+            "    {\n"
+            "      \"name\" : \"name\"          (string) The wallet name\n"
+            "    }\n"
+            "    ,...\n"
+            "  ]\n"
+            "}\n"
+            "\nExamples:\n"
+            + HelpExampleCli("listwalletdir", "")
+            + HelpExampleRpc("listwalletdir", "")
+        );
+    }
+
+    UniValue wallets(UniValue::VARR);
+    for (const auto& path : ListWalletDir()) {
+        UniValue wallet(UniValue::VOBJ);
+        wallet.pushKV("name", path.string());
+        wallets.push_back(wallet);
+    }
+
+    UniValue result(UniValue::VOBJ);
+    result.pushKV("wallets", wallets);
+    return result;
+}
+
 static UniValue listwallets(const JSONRPCRequest& request)
 {
     if (request.fHelp || request.params.size() != 0)
@@ -4717,6 +4749,7 @@ static const CRPCCommand commands[] =
     { "wallet",             "listsinceblock",           &listsinceblock,           {"blockhash","target_confirmations","include_watchonly","include_removed"} },
     { "wallet",             "listtransactions",         &listtransactions,         {"account|label|dummy","count","skip","include_watchonly"} },
     { "wallet",             "listunspent",              &listunspent,              {"minconf","maxconf","addresses","include_unsafe","query_options"} },
+    { "wallet",             "listwalletdir",                    &listwalletdir,                 {} },
     { "wallet",             "listwallets",              &listwallets,              {} },
     { "wallet",             "loadwallet",               &loadwallet,               {"filename"} },
     { "wallet",             "lockunspent",                      &lockunspent,                   {"unlock","transactions"} },

src/wallet/walletutil.cpp

@@ -3,6 +3,7 @@
 // file COPYING or http://www.opensource.org/licenses/mit-license.php.
 
 #include <wallet/walletutil.h>
+#include <util/system.h>
 
 fs::path GetWalletDir()
 {
@@ -26,6 +27,54 @@ fs::path GetWalletDir()
     return path;
 }
 
+static bool IsBerkeleyBtree(const fs::path& path)
+{
+    // A Berkeley DB Btree file has at least 4K.
+    // This check also prevents opening lock files.
+    boost::system::error_code ec;
+    if (fs::file_size(path, ec) < 4096) return false;
+
+    fs::ifstream file(path.string(), std::ios::binary);
+    if (!file.is_open()) return false;
+
+    file.seekg(12, std::ios::beg); // Magic bytes start at offset 12
+    uint32_t data = 0;
+    file.read((char*) &data, sizeof(data)); // Read 4 bytes of file to compare against magic
+
+    // Berkeley DB Btree magic bytes, from:
+    //  https://github.com/file/file/blob/5824af38469ec1ca9ac3ffd251e7afe9dc11e227/magic/Magdir/database#L74-L75
+    //  - big endian systems - 00 05 31 62
+    //  - little endian systems - 62 31 05 00
+    return data == 0x00053162 || data == 0x62310500;
+}
+
+std::vector<fs::path> ListWalletDir()
+{
+    const fs::path wallet_dir = GetWalletDir();
+    std::vector<fs::path> paths;
+
+    for (auto it = fs::recursive_directory_iterator(wallet_dir); it != end(it); ++it) {
+        if (it->status().type() == fs::directory_file && IsBerkeleyBtree(it->path() / "wallet.dat")) {
+            // Found a directory which contains wallet.dat btree file, add it as a wallet.
+            paths.emplace_back(fs::relative(it->path(), wallet_dir));
+        } else if (it.level() == 0 && it->symlink_status().type() == fs::regular_file && IsBerkeleyBtree(it->path())) {
+            if (it->path().filename() == "wallet.dat") {
+                // Found top-level wallet.dat btree file, add top level directory ""
+                // as a wallet.
+                paths.emplace_back();
+            } else {
+                // Found top-level btree file not called wallet.dat. Current bitcoin
+                // software will never create these files but will allow them to be
+                // opened in a shared database environment for backwards compatibility.
+                // Add it to the list of available wallets.
+                paths.emplace_back(fs::relative(it->path(), wallet_dir));
+            }
+        }
+    }
+
+    return paths;
+}
+
 WalletLocation::WalletLocation(const std::string& name)
     : m_name(name)
     , m_path(fs::absolute(name, GetWalletDir()))

src/wallet/walletutil.h

@@ -7,10 +7,16 @@
 
 #include <chainparamsbase.h>
 #include <util/system.h>
+#include <fs.h>
+
+#include <vector>
 
 //! Get the path of the wallet directory.
 fs::path GetWalletDir();
 
+//! Get wallets in wallet directory.
+std::vector<fs::path> ListWalletDir();
+
 //! The WalletLocation class provides wallet information.
 class WalletLocation final
 {

test/functional/wallet_multiwallet.py

@@ -36,6 +36,8 @@ def wallet_file(name):
                 return wallet_dir(name, "wallet.dat")
             return wallet_dir(name)
 
+        assert_equal(self.nodes[0].listwalletdir(), { 'wallets': [{ 'name': '' }] })
+
         # check wallet.dat is created
         self.stop_nodes()
         assert_equal(os.path.isfile(wallet_dir('wallet.dat')), True)
@@ -66,6 +68,8 @@ def wallet_file(name):
         wallet_names = ['w1', 'w2', 'w3', 'w', 'sub/w5', os.path.join(self.options.tmpdir, 'extern/w6'), 'w7_symlink', 'w8', '']
         extra_args = ['-wallet={}'.format(n) for n in wallet_names]
         self.start_node(0, extra_args)
+        assert_equal(set(map(lambda w: w['name'], self.nodes[0].listwalletdir()['wallets'])), set(['', 'w3', 'w2', 'sub/w5', 'w7', 'w7', 'w1', 'w8', 'w']))
+
         assert_equal(set(node.listwallets()), set(wallet_names))
 
         # check that all requested wallets were created
@@ -137,6 +141,8 @@ def wallet_file(name):
 
         self.restart_node(0, extra_args)
 
+        assert_equal(set(map(lambda w: w['name'], self.nodes[0].listwalletdir()['wallets'])), set(['', 'w3', 'w2', 'sub/w5', 'w7', 'w7', 'w8_copy', 'w1', 'w8', 'w']))
+
         wallets = [wallet(w) for w in wallet_names]
         wallet_bad = wallet("bad")
 
@@ -285,6 +291,8 @@ def wallet_file(name):
         assert_equal(self.nodes[0].listwallets(), ['w1'])
         assert_equal(w1.getwalletinfo()['walletname'], 'w1')
 
+        assert_equal(set(map(lambda w: w['name'], self.nodes[0].listwalletdir()['wallets'])), set(['', 'w3', 'w2', 'sub/w5', 'w7', 'w9', 'w7', 'w8_copy', 'w1', 'w8', 'w']))
+
         # Test backing up and restoring wallets
         self.log.info("Test wallet backup")
         self.restart_node(0, ['-nowallet'])