Merge pull request #3994

1d17647 epee.string_tools: add conversion between UTF-8 and UTF-16 (stoffu)
59de6f8 util: add file_locker class (stoffu)
3d623a8 wallet: prevent the same wallet file from being opened by multiple processes (stoffu)

5 files changed, 110 insertions, 12 deletions

diff --git a/src/common/util.cpp b/src/common/util.cpp
index 329352e94..eed6fd8d2 100644
--- a/src/common/util.cpp
+++ b/src/common/util.cpp
@@ -195,6 +195,73 @@ namespace tools
     catch (...) {}
   }
 
+  file_locker::file_locker(const std::string &filename)
+  {
+#ifdef WIN32
+    m_fd = INVALID_HANDLE_VALUE;
+    std::wstring filename_wide;
+    try
+    {
+      filename_wide = string_tools::utf8_to_utf16(filename);
+    }
+    catch (const std::exception &e)
+    {
+      MERROR("Failed to convert path \"" << filename << "\" to UTF-16: " << e.what());
+      return;
+    }
+    m_fd = CreateFileW(filename_wide.c_str(), GENERIC_READ, 0, NULL, OPEN_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL);
+    if (m_fd != INVALID_HANDLE_VALUE)
+    {
+      OVERLAPPED ov;
+      memset(&ov, 0, sizeof(ov));
+      if (!LockFileEx(m_fd, LOCKFILE_FAIL_IMMEDIATELY | LOCKFILE_EXCLUSIVE_LOCK, 0, 1, 0, &ov))
+      {
+        MERROR("Failed to lock " << filename << ": " << std::error_code(GetLastError(), std::system_category()));
+        CloseHandle(m_fd);
+        m_fd = INVALID_HANDLE_VALUE;
+      }
+    }
+    else
+    {
+      MERROR("Failed to open " << filename << ": " << std::error_code(GetLastError(), std::system_category()));
+    }
+#else
+    m_fd = open(filename, O_RDONLY | O_CREAT, 0666);
+    if (m_fd != -1)
+    {
+      if (flock(m_fd, LOCK_EX | LOCK_NB) == -1)
+      {
+        MERROR("Failed to lock " << filename << ": " << std::strerr(errno));
+        close(m_fd);
+        m_fd = -1;
+      }
+    }
+    else
+    {
+      MERROR("Failed to open " << filename << ": " << std::strerr(errno));
+    }
+#endif
+  }
+  file_locker::~file_locker()
+  {
+    if (locked())
+    {
+#ifdef WIN32
+      CloseHandle(m_fd);
+#else
+      close(m_fd);
+#endif
+    }
+  }
+  bool file_locker::locked() const
+  {
+#ifdef WIN32
+    return m_fd != INVALID_HANDLE_VALUE;
+#else
+    return m_fd != -1;
+#endif
+  }
+
 #ifdef WIN32
   std::string get_windows_version_display_string()
   {
@@ -451,10 +518,15 @@ std::string get_nix_version_display_string()
 
     if (SHGetSpecialFolderPathW(NULL, psz_path, nfolder, iscreate))
     {
-      int size_needed = WideCharToMultiByte(CP_UTF8, 0, psz_path, wcslen(psz_path), NULL, 0, NULL, NULL);
-      std::string folder_name(size_needed, 0);
-      WideCharToMultiByte(CP_UTF8, 0, psz_path, wcslen(psz_path), &folder_name[0], size_needed, NULL, NULL);
-      return folder_name;
+      try
+      {
+        return string_tools::utf16_to_utf8(psz_path);
+      }
+      catch (const std::exception &e)
+      {
+        MERROR("utf16_to_utf8 failed: " << e.what());
+        return "";
+      }
     }
 
     LOG_ERROR("SHGetSpecialFolderPathW() failed, could not obtain requested path.");
@@ -515,18 +587,20 @@ std::string get_nix_version_display_string()
     int code;
 #if defined(WIN32)
     // Maximizing chances for success
-    WCHAR wide_replacement_name[1000];
-    MultiByteToWideChar(CP_UTF8, 0, replacement_name.c_str(), replacement_name.size() + 1, wide_replacement_name, 1000);
-    WCHAR wide_replaced_name[1000];
-    MultiByteToWideChar(CP_UTF8, 0, replaced_name.c_str(), replaced_name.size() + 1, wide_replaced_name, 1000);
-
-    DWORD attributes = ::GetFileAttributesW(wide_replaced_name);
+    std::wstring wide_replacement_name;
+    try { wide_replacement_name = string_tools::utf8_to_utf16(replacement_name); }
+    catch (...) { return std::error_code(GetLastError(), std::system_category()); }
+    std::wstring wide_replaced_name;
+    try { wide_replaced_name = string_tools::utf8_to_utf16(replaced_name); }
+    catch (...) { return std::error_code(GetLastError(), std::system_category()); }
+
+    DWORD attributes = ::GetFileAttributesW(wide_replaced_name.c_str());
     if (INVALID_FILE_ATTRIBUTES != attributes)
     {
-      ::SetFileAttributesW(wide_replaced_name, attributes & (~FILE_ATTRIBUTE_READONLY));
+      ::SetFileAttributesW(wide_replaced_name.c_str(), attributes & (~FILE_ATTRIBUTE_READONLY));
     }
 
-    bool ok = 0 != ::MoveFileExW(wide_replacement_name, wide_replaced_name, MOVEFILE_REPLACE_EXISTING);
+    bool ok = 0 != ::MoveFileExW(wide_replacement_name.c_str(), wide_replaced_name.c_str(), MOVEFILE_REPLACE_EXISTING);
     code = ok ? 0 : static_cast<int>(::GetLastError());
 #else
     bool ok = 0 == std::rename(replacement_name.c_str(), replaced_name.c_str());
diff --git a/src/common/util.h b/src/common/util.h
index dc426830b..a57a85fee 100644
--- a/src/common/util.h
+++ b/src/common/util.h
@@ -91,6 +91,20 @@ namespace tools
     const std::string& filename() const noexcept { return m_filename; }
   };
 
+  class file_locker
+  {
+  public:
+    file_locker(const std::string &filename);
+    ~file_locker();
+    bool locked() const;
+  private:
+#ifdef WIN32
+    HANDLE m_fd;
+#else
+    int m_fd;
+#endif
+  };
+
   /*! \brief Returns the default data directory.
    *
    * \details Windows < Vista: C:\\Documents and Settings\\Username\\Application Data\\CRYPTONOTE_NAME
diff --git a/src/wallet/api/wallet.cpp b/src/wallet/api/wallet.cpp
index c7dbd29e4..e2c4fe7af 100644
--- a/src/wallet/api/wallet.cpp
+++ b/src/wallet/api/wallet.cpp
@@ -721,6 +721,7 @@ bool WalletImpl::close(bool store)
         LOG_PRINT_L1("Calling wallet::stop...");
         m_wallet->stop();
         LOG_PRINT_L1("wallet::stop done");
+        m_wallet->deinit();
         result = true;
         clearStatus();
     } catch (const std::exception &e) {
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index 28049fe92..f07736ebd 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -2636,6 +2636,7 @@ void wallet2::detach_blockchain(uint64_t height)
 bool wallet2::deinit()
 {
   m_is_initialized=false;
+  m_keys_file_locker.reset();
   return true;
 }
 //----------------------------------------------------------------------------------------------------
@@ -2802,10 +2803,12 @@ bool wallet2::store_keys(const std::string& keys_file_name, const epee::wipeable
   crypto::chacha20(account_data.data(), account_data.size(), key, keys_file_data.iv, &cipher[0]);
   keys_file_data.account_data = cipher;
 
+  m_keys_file_locker.reset();
   std::string buf;
   r = ::serialization::dump_binary(keys_file_data, buf);
   r = r && epee::file_io_utils::save_string_to_file(keys_file_name, buf); //and never touch wallet_keys_file again, only read
   CHECK_AND_ASSERT_MES(r, false, "failed to generate wallet keys file " << keys_file_name);
+  m_keys_file_locker.reset(new tools::file_locker(m_keys_file));
 
   return true;
 }
@@ -3935,12 +3938,17 @@ void wallet2::load(const std::string& wallet_, const epee::wipeable_string& pass
   boost::system::error_code e;
   bool exists = boost::filesystem::exists(m_keys_file, e);
   THROW_WALLET_EXCEPTION_IF(e || !exists, error::file_not_found, m_keys_file);
+  m_keys_file_locker.reset(new tools::file_locker(m_keys_file));
+  THROW_WALLET_EXCEPTION_IF(!m_keys_file_locker->locked(), error::wallet_internal_error, "internal error: \"" + m_keys_file + "\" is opened by another wallet program");
 
+  // this temporary unlocking is necessary for Windows (otherwise the file couldn't be loaded).
+  m_keys_file_locker.reset();
   if (!load_keys(m_keys_file, password))
   {
     THROW_WALLET_EXCEPTION_IF(true, error::file_read_error, m_keys_file);
   }
   LOG_PRINT_L0("Loaded wallet keys file, with public address: " << m_account.get_public_address_str(m_nettype));
+  m_keys_file_locker.reset(new tools::file_locker(m_keys_file));
 
   //keys loaded ok!
   //try to load wallet file. but even if we failed, it is not big problem
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index 705933979..d33d8258b 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -1308,6 +1308,7 @@ namespace tools
     boost::optional<crypto::chacha_key> m_ringdb_key;
 
     uint64_t m_last_block_reward;
+    std::unique_ptr<tools::file_locker> m_keys_file_locker;
   };
 }
 BOOST_CLASS_VERSION(tools::wallet2, 25)