Merge #13339: wallet: Replace %w by wallet name in -walletnotify script

4e9efac678a9c0ea4e4c7dd956ea036ae6cf17ec test: Check wallet name in -walletnotify script (João Barbosa)
9a5b5ee81f15b1d89cb25ff3e137a672536cdc46 wallet: Replace %w by wallet name in -walletnotify script (João Barbosa)

Pull request description:

  Fixes #13237.

ACKs for top commit:
  laanwj:
    ACK 4e9efac678a9c0ea4e4c7dd956ea036ae6cf17ec

Tree-SHA512: 189dd1c785485f2e974d7c12531851b2a977778b3b954aa95efd527322ba3345924cfd587fb9c90b0fa979202af0ab2d90e53d125fe266a36c94f757e4176203

5 files changed, 37 insertions, 4 deletions

diff --git a/src/util/system.cpp b/src/util/system.cpp
index 13ff99c663..b0a538b527 100644
--- a/src/util/system.cpp
+++ b/src/util/system.cpp
@@ -63,6 +63,7 @@
 #include <malloc.h>
 #endif
 
+#include <boost/algorithm/string/replace.hpp>
 #include <thread>
 #include <typeinfo>
 #include <univalue.h>
@@ -1047,6 +1048,15 @@ fs::path GetSpecialFolderPath(int nFolder, bool fCreate)
 }
 #endif
 
+#ifndef WIN32
+std::string ShellEscape(const std::string& arg)
+{
+    std::string escaped = arg;
+    boost::replace_all(escaped, "'", "'\"'\"'");
+    return "'" + escaped + "'";
+}
+#endif
+
 #if HAVE_SYSTEM
 void runCommand(const std::string& strCommand)
 {
diff --git a/src/util/system.h b/src/util/system.h
index bb69181de9..3138522b5c 100644
--- a/src/util/system.h
+++ b/src/util/system.h
@@ -81,6 +81,9 @@ fs::path GetConfigFile(const std::string& confPath);
 #ifdef WIN32
 fs::path GetSpecialFolderPath(int nFolder, bool fCreate = true);
 #endif
+#ifndef WIN32
+std::string ShellEscape(const std::string& arg);
+#endif
 #if HAVE_SYSTEM
 void runCommand(const std::string& strCommand);
 #endif
diff --git a/src/wallet/init.cpp b/src/wallet/init.cpp
index 2ebc9aba39..50f064b305 100644
--- a/src/wallet/init.cpp
+++ b/src/wallet/init.cpp
@@ -62,7 +62,7 @@ void WalletInit::AddWalletOptions() const
     gArgs.AddArg("-walletbroadcast",  strprintf("Make the wallet broadcast transactions (default: %u)", DEFAULT_WALLETBROADCAST), ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);
     gArgs.AddArg("-walletdir=<dir>", "Specify directory to hold wallets (default: <datadir>/wallets if it exists, otherwise <datadir>)", ArgsManager::ALLOW_ANY | ArgsManager::NETWORK_ONLY, OptionsCategory::WALLET);
 #if HAVE_SYSTEM
-    gArgs.AddArg("-walletnotify=<cmd>", "Execute command when a wallet transaction changes (%s in cmd is replaced by TxID)", ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);
+    gArgs.AddArg("-walletnotify=<cmd>", "Execute command when a wallet transaction changes. %s in cmd is replaced by TxID and %w is replaced by wallet name. %w is not currently implemented on windows. On systems where %w is supported, it should NOT be quoted because this would break shell escaping used to invoke the command.", ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);
 #endif
     gArgs.AddArg("-walletrbf", strprintf("Send transactions with full-RBF opt-in enabled (RPC only, default: %u)", DEFAULT_WALLET_RBF), ArgsManager::ALLOW_ANY, OptionsCategory::WALLET);
     gArgs.AddArg("-zapwallettxes=<mode>", "Delete all wallet transactions and only recover those parts of the blockchain through -rescan on startup"
diff --git a/src/wallet/wallet.cpp b/src/wallet/wallet.cpp
index 405afb6d8d..6b9f53f7c5 100644
--- a/src/wallet/wallet.cpp
+++ b/src/wallet/wallet.cpp
@@ -847,6 +847,14 @@ bool CWallet::AddToWallet(const CWalletTx& wtxIn, bool fFlushOnClose)
     if (!strCmd.empty())
     {
         boost::replace_all(strCmd, "%s", wtxIn.GetHash().GetHex());
+#ifndef WIN32
+        // Substituting the wallet name isn't currently supported on windows
+        // because windows shell escaping has not been implemented yet:
+        // https://github.com/bitcoin/bitcoin/pull/13339#issuecomment-537384875
+        // A few ways it could be implemented in the future are described in:
+        // https://github.com/bitcoin/bitcoin/pull/13339#issuecomment-461288094
+        boost::replace_all(strCmd, "%w", ShellEscape(GetName()));
+#endif
         std::thread t(runCommand, strCmd);
         t.detach(); // thread runs free
     }
diff --git a/test/functional/feature_notifications.py b/test/functional/feature_notifications.py
index da00b773ad..b110a559c0 100755
--- a/test/functional/feature_notifications.py
+++ b/test/functional/feature_notifications.py
@@ -13,6 +13,16 @@ from test_framework.util import (
     connect_nodes,
 )
 
+# Linux allow all characters other than \x00
+# Windows disallow control characters (0-31) and /\?%:|"<>
+FILE_CHAR_START = 32 if os.name == 'nt' else 1
+FILE_CHAR_END = 128
+FILE_CHAR_BLACKLIST = '/\\?%*:|"<>' if os.name == 'nt' else '/'
+
+
+def notify_outputname(walletname, txid):
+    return txid if os.name == 'nt' else '{}_{}'.format(walletname, txid)
+
 
 class NotificationsTest(BitcoinTestFramework):
     def set_test_params(self):
@@ -20,6 +30,7 @@ class NotificationsTest(BitcoinTestFramework):
         self.setup_clean_chain = True
 
     def setup_network(self):
+        self.wallet = ''.join(chr(i) for i in range(FILE_CHAR_START, FILE_CHAR_END) if chr(i) not in FILE_CHAR_BLACKLIST)
         self.alertnotify_dir = os.path.join(self.options.tmpdir, "alertnotify")
         self.blocknotify_dir = os.path.join(self.options.tmpdir, "blocknotify")
         self.walletnotify_dir = os.path.join(self.options.tmpdir, "walletnotify")
@@ -33,7 +44,8 @@ class NotificationsTest(BitcoinTestFramework):
                             "-blocknotify=echo > {}".format(os.path.join(self.blocknotify_dir, '%s'))],
                            ["-blockversion=211",
                             "-rescan",
-                            "-walletnotify=echo > {}".format(os.path.join(self.walletnotify_dir, '%s'))]]
+                            "-wallet={}".format(self.wallet),
+                            "-walletnotify=echo > {}".format(os.path.join(self.walletnotify_dir, notify_outputname('%w', '%s')))]]
         super().setup_network()
 
     def run_test(self):
@@ -53,7 +65,7 @@ class NotificationsTest(BitcoinTestFramework):
             wait_until(lambda: len(os.listdir(self.walletnotify_dir)) == block_count, timeout=10)
 
             # directory content should equal the generated transaction hashes
-            txids_rpc = list(map(lambda t: t['txid'], self.nodes[1].listtransactions("*", block_count)))
+            txids_rpc = list(map(lambda t: notify_outputname(self.wallet, t['txid']), self.nodes[1].listtransactions("*", block_count)))
             assert_equal(sorted(txids_rpc), sorted(os.listdir(self.walletnotify_dir)))
             self.stop_node(1)
             for tx_file in os.listdir(self.walletnotify_dir):
@@ -67,7 +79,7 @@ class NotificationsTest(BitcoinTestFramework):
             wait_until(lambda: len(os.listdir(self.walletnotify_dir)) == block_count, timeout=10)
 
             # directory content should equal the generated transaction hashes
-            txids_rpc = list(map(lambda t: t['txid'], self.nodes[1].listtransactions("*", block_count)))
+            txids_rpc = list(map(lambda t: notify_outputname(self.wallet, t['txid']), self.nodes[1].listtransactions("*", block_count)))
             assert_equal(sorted(txids_rpc), sorted(os.listdir(self.walletnotify_dir)))
 
         # TODO: add test for `-alertnotify` large fork notifications