Merge #15297: wallet: Releases dangling files on BerkeleyEnvironment::Close

d3bf3b930 qa: Test .walletlock file is closed (João Barbosa)
2f8b8f479 wallet: Close wallet env lock file (João Barbosa)
8602a1e6a wallet: Close dbenv error file db.log (João Barbosa)

Pull request description:

  This PR closes `db.log` and removes `.walletlock` files when `BerkeleyEnvironment` is closed.

  Fixes https://github.com/bitcoin/bitcoin/issues/15291#issuecomment-459131886.

Tree-SHA512: 05d8b027feea914e0ba873e75d117857473d1fd7b400e41bd473d638171fa39d5be048990bf685dc0807f7d92418579b763056dc2a6dcf6b96777d5688ddee04

src/util/system.cpp

@@ -111,6 +111,12 @@ bool LockDirectory(const fs::path& directory, const std::string lockfile_name, b
     return true;
 }
 
+void UnlockDirectory(const fs::path& directory, const std::string& lockfile_name)
+{
+    std::lock_guard<std::mutex> lock(cs_dir_locks);
+    dir_locks.erase((directory / lockfile_name).string());
+}
+
 void ReleaseDirectoryLocks()
 {
     std::lock_guard<std::mutex> ulock(cs_dir_locks);

src/util/system.h

@@ -70,6 +70,7 @@ int RaiseFileDescriptorLimit(int nMinFD);
 void AllocateFileRange(FILE *file, unsigned int offset, unsigned int length);
 bool RenameOver(fs::path src, fs::path dest);
 bool LockDirectory(const fs::path& directory, const std::string lockfile_name, bool probe_only=false);
+void UnlockDirectory(const fs::path& directory, const std::string& lockfile_name);
 bool DirIsWritable(const fs::path& directory);
 
 /** Release all directory locks. This is used for unit testing only, at runtime

src/wallet/db.cpp

@@ -126,11 +126,18 @@ void BerkeleyEnvironment::Close()
         }
     }
 
+    FILE* error_file = nullptr;
+    dbenv->get_errfile(&error_file);
+
     int ret = dbenv->close(0);
     if (ret != 0)
         LogPrintf("BerkeleyEnvironment::Close: Error %d closing database environment: %s\n", ret, DbEnv::strerror(ret));
     if (!fMockDb)
         DbEnv((u_int32_t)0).remove(strPath.c_str(), 0);
+
+    if (error_file) fclose(error_file);
+
+    UnlockDirectory(strPath, ".walletlock");
 }
 
 void BerkeleyEnvironment::Reset()

test/functional/wallet_multiwallet.py

@@ -315,6 +315,14 @@ class MultiWalletTest(BitcoinTestFramework):
             self.nodes[0].loadwallet(wallet_name)
             assert_equal(rpc.getaddressinfo(addr)['ismine'], True)
 
+        # Test .walletlock file is closed
+        self.start_node(1)
+        wallet = os.path.join(self.options.tmpdir, 'my_wallet')
+        self.nodes[0].createwallet(wallet)
+        assert_raises_rpc_error(-4, "Error initializing wallet database environment", self.nodes[1].loadwallet, wallet)
+        self.nodes[0].unloadwallet(wallet)
+        self.nodes[1].loadwallet(wallet)
+
 
 if __name__ == '__main__':
     MultiWalletTest().main()