From 010e6c73baf3772c00d72ca4098f8ce5992cfa6c Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sat, 30 Aug 2025 20:26:03 +0300
Subject: [PATCH 01/13] Draft test framework (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/.clang-format           |  16 ++++
 lab/vtpc/.clang-tidy             |  21 ++++++
 lab/vtpc/.gitignore              |   8 ++
 lab/vtpc/.vscode/settings.json   |   7 ++
 lab/vtpc/CMakeLists.txt          |  12 +++
 lab/vtpc/README.md               |  47 ++++++++++++
 lab/vtpc/lib/CMakeLists.txt      |  11 +++
 lab/vtpc/lib/vtpc.c              |  28 +++++++
 lab/vtpc/lib/vtpc.h              |  10 +++
 lab/vtpc/test/CMakeLists.txt     |   9 +++
 lab/vtpc/test/lib/CMakeLists.txt |  10 +++
 lab/vtpc/test/lib/cmp_file.cpp   |  69 +++++++++++++++++
 lab/vtpc/test/lib/cmp_file.hpp   |  24 ++++++
 lab/vtpc/test/lib/exception.cpp  |   1 +
 lab/vtpc/test/lib/exception.hpp  |  34 +++++++++
 lab/vtpc/test/lib/file.cpp       | 123 +++++++++++++++++++++++++++++++
 lab/vtpc/test/lib/file.hpp       |  33 +++++++++
 lab/vtpc/test/test_basic.cpp     |  33 +++++++++
 18 files changed, 496 insertions(+)
 create mode 100644 lab/vtpc/.clang-format
 create mode 100644 lab/vtpc/.clang-tidy
 create mode 100644 lab/vtpc/.gitignore
 create mode 100644 lab/vtpc/.vscode/settings.json
 create mode 100644 lab/vtpc/CMakeLists.txt
 create mode 100644 lab/vtpc/README.md
 create mode 100644 lab/vtpc/lib/CMakeLists.txt
 create mode 100644 lab/vtpc/lib/vtpc.c
 create mode 100644 lab/vtpc/lib/vtpc.h
 create mode 100644 lab/vtpc/test/CMakeLists.txt
 create mode 100644 lab/vtpc/test/lib/CMakeLists.txt
 create mode 100644 lab/vtpc/test/lib/cmp_file.cpp
 create mode 100644 lab/vtpc/test/lib/cmp_file.hpp
 create mode 100644 lab/vtpc/test/lib/exception.cpp
 create mode 100644 lab/vtpc/test/lib/exception.hpp
 create mode 100644 lab/vtpc/test/lib/file.cpp
 create mode 100644 lab/vtpc/test/lib/file.hpp
 create mode 100644 lab/vtpc/test/test_basic.cpp

diff --git a/lab/vtpc/.clang-format b/lab/vtpc/.clang-format
new file mode 100644
index 0000000..dd99110
--- /dev/null
+++ b/lab/vtpc/.clang-format
@@ -0,0 +1,16 @@
+BasedOnStyle: Google
+
+AccessModifierOffset: -2
+
+AllowShortFunctionsOnASingleLine: None
+AllowShortIfStatementsOnASingleLine: false
+AllowShortLoopsOnASingleLine: false
+
+DerivePointerAlignment: false
+BreakConstructorInitializers: BeforeComma
+AlignAfterOpenBracket: BlockIndent
+
+BinPackArguments: false
+BinPackParameters: false
+
+AlignArrayOfStructures: Right
diff --git a/lab/vtpc/.clang-tidy b/lab/vtpc/.clang-tidy
new file mode 100644
index 0000000..07e1c89
--- /dev/null
+++ b/lab/vtpc/.clang-tidy
@@ -0,0 +1,21 @@
+Checks: |
+    -*,
+    bugprone-*,
+    -bugprone-easily-swappable-parameters,
+    cert-*,
+    clang-analyzer-*,
+    concurrency-*,
+    cppcoreguidelines-*,
+    -cppcoreguidelines-avoid-non-const-global-variables,
+    -cppcoreguidelines-special-member-functions,
+    google-*,
+    hicpp-*,
+    -hicpp-special-member-functions,
+    misc-*,
+    modernize-*,
+    performance-*,
+    portability-*,
+    readability-*
+    -readability-identifier-length
+WarningsAsErrors: '*'
+FormatStyle: file
diff --git a/lab/vtpc/.gitignore b/lab/vtpc/.gitignore
new file mode 100644
index 0000000..fb90d94
--- /dev/null
+++ b/lab/vtpc/.gitignore
@@ -0,0 +1,8 @@
+# CMake
+build/
+
+# Clangd
+.cache/
+
+# Python
+__pycache__/
diff --git a/lab/vtpc/.vscode/settings.json b/lab/vtpc/.vscode/settings.json
new file mode 100644
index 0000000..db30e90
--- /dev/null
+++ b/lab/vtpc/.vscode/settings.json
@@ -0,0 +1,7 @@
+{
+    "clangd.arguments": [
+        "-compile-commands-dir=./build",
+        "-header-insertion=never",
+    ],
+    "files.eol": "\n",
+}
diff --git a/lab/vtpc/CMakeLists.txt b/lab/vtpc/CMakeLists.txt
new file mode 100644
index 0000000..478cbae
--- /dev/null
+++ b/lab/vtpc/CMakeLists.txt
@@ -0,0 +1,12 @@
+cmake_minimum_required(VERSION 3.12)
+
+project(
+    vtpc
+    VERSION 0.1
+    DESCRIPTION "VT Page Cache"
+)
+
+set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
+
+add_subdirectory(lib)
+add_subdirectory(test)
diff --git a/lab/vtpc/README.md b/lab/vtpc/README.md
new file mode 100644
index 0000000..78e4047
--- /dev/null
+++ b/lab/vtpc/README.md
@@ -0,0 +1,47 @@
+# Базовый трек. Лабораторная работа 2
+
+## Задание
+
+Для оптимизации работы с блочными устройствами в ОС существует кэш страниц с данными, которыми мы производим операции чтения и записи на диск. Такой кэш позволяет избежать высоких задержек при повторном доступе к данным, так как операция будет выполнена с данными в RAM, а не на диске (вспомним пирамиду памяти).
+
+В данной лабораторной работе необходимо реализовать блочный кэш в пространстве пользователя в виде динамической библиотеки. Политику вытеснения страниц и другие элементы задания необходимо получить у преподавателя.
+
+При выполнении работы необходимо реализовать простой API для работы с файлами, предоставляющий пользователю следующие возможности:
+
+1. Открытие файла по заданному пути файла, доступного для чтения. Процедура возвращает некоторый хэндл на файл. Пример: `int lab2_open(const char *path)`.
+
+2. Закрытие файла по хэндлу. Пример: `int lab2_close(int fd)`.
+
+3. Чтение данных из файла. Пример: `ssize_t lab2_read(int fd, void buf[.count], size_t count)`.
+
+4. Запись данных в файл. Пример: `ssize_t lab2_write(int fd, const void buf[.count], size_t count)`.
+
+5. Перестановка позиции указателя на данные файла. Достаточно поддержать только абсолютные координаты. Пример: `​​​​​​​off_t lab2_lseek(int fd, off_t offset, int whence)`.
+
+6. Синхронизация данных из кэша с диском. Пример: `int lab2_fsync(int fd)`.
+
+Операции с диском разработанного блочного кеша должны производиться в обход page cache ОС.
+
+В рамках проверки работоспособности разработанного блочного кэша необходимо адаптировать указанную преподавателем программу-загрузчик из ЛР 1, добавив использование кэша. Запустите программу и убедитесь, что она корректно работает. Сравните производительность до и после.
+
+## Ограничения
+
+1. Программа (комплекс программ) должна быть реализован на языке C.
+
+2. Если по выданному варианту задана политика вытеснения Optimal, то необходимо предоставить пользователю возможность подсказать page cache, когда будет совершен следующий доступ к данным. Это можно сделать либо добавив параметр в процедуры `read` и `write` (например, `ssize_t lab2_read(int fd, void buf[.count], size_t count, access_hint_t hint)`), либо добавив еще одну функцию в API (например, `int lab2_advice(int fd, off_t offset, access_hint_t hint)`). `access_hint_t` в данном случае – это абсолютное время или временной интервал, по которому разработанное API будет определять время последующего доступа к данным.
+
+3. Запрещено использовать высокоуровневые абстракции над системными вызовами.
+
+## Требования к отчету и защите
+
+Отчет должен содержать:
+
+1. титульный лист с указанием номера и названия ЛР, вашего ФИО, ФИО преподавателя практики, номера вашей группы, варианта ЛР;
+
+2. текст задания в соответствии с вариантом;
+
+3. краткий обзор кода;
+
+4. данные о работе программы-нагрузчика до и после внедрения своего page cache;
+
+5. заключение с анализом результатов и выводом.
diff --git a/lab/vtpc/lib/CMakeLists.txt b/lab/vtpc/lib/CMakeLists.txt
new file mode 100644
index 0000000..e904b37
--- /dev/null
+++ b/lab/vtpc/lib/CMakeLists.txt
@@ -0,0 +1,11 @@
+add_library(
+    vtpc
+    STATIC
+    vtpc.c
+)
+
+target_include_directories(
+    vtpc
+    PUBLIC
+    .
+)
diff --git a/lab/vtpc/lib/vtpc.c b/lab/vtpc/lib/vtpc.c
new file mode 100644
index 0000000..3b678bd
--- /dev/null
+++ b/lab/vtpc/lib/vtpc.c
@@ -0,0 +1,28 @@
+#include "vtpc.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+
+int vtpc_open(const char* path, int mode) {
+  return open(path, mode);
+}
+
+int vtpc_close(int fd) {
+  return close(fd);
+}
+
+ssize_t vtpc_read(int fd, void* buf, size_t count) {
+  return read(fd, buf, count);
+}
+
+ssize_t vtpc_write(int fd, const void* buf, size_t count) {
+  return write(fd, buf, count);
+}
+
+off_t vtpc_lseek(int fd, off_t offset, int whence) {
+  return lseek(fd, offset, whence);
+}
+
+int vtpc_fsync(int fd) {
+  return fsync(fd);
+}
diff --git a/lab/vtpc/lib/vtpc.h b/lab/vtpc/lib/vtpc.h
new file mode 100644
index 0000000..fa817e2
--- /dev/null
+++ b/lab/vtpc/lib/vtpc.h
@@ -0,0 +1,10 @@
+#pragma once
+
+#include <sys/types.h>
+
+int vtpc_open(const char* path, int mode);
+int vtpc_close(int fd);
+ssize_t vtpc_read(int fd, void* buf, size_t count);
+ssize_t vtpc_write(int fd, const void* buf, size_t count);
+off_t vtpc_lseek(int fd, off_t offset, int whence);
+int vtpc_fsync(int fd);
diff --git a/lab/vtpc/test/CMakeLists.txt b/lab/vtpc/test/CMakeLists.txt
new file mode 100644
index 0000000..5136fb4
--- /dev/null
+++ b/lab/vtpc/test/CMakeLists.txt
@@ -0,0 +1,9 @@
+set(CMAKE_CXX_STANDARD 23)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
+add_subdirectory(lib)
+
+add_executable(test_basic test_basic.cpp)
+target_include_directories(test_basic PUBLIC .)
+target_link_libraries(test_basic PRIVATE vt)
diff --git a/lab/vtpc/test/lib/CMakeLists.txt b/lab/vtpc/test/lib/CMakeLists.txt
new file mode 100644
index 0000000..ec729a6
--- /dev/null
+++ b/lab/vtpc/test/lib/CMakeLists.txt
@@ -0,0 +1,10 @@
+add_library(
+    vt
+    STATIC
+    cmp_file.cpp
+    exception.cpp
+    file.cpp
+)
+
+target_include_directories(vt PUBLIC .)
+target_link_libraries(vt PRIVATE vtpc)
diff --git a/lab/vtpc/test/lib/cmp_file.cpp b/lab/vtpc/test/lib/cmp_file.cpp
new file mode 100644
index 0000000..99221e3
--- /dev/null
+++ b/lab/vtpc/test/lib/cmp_file.cpp
@@ -0,0 +1,69 @@
+#include "cmp_file.hpp"
+
+#include <optional>
+
+#include "exception.hpp"
+#include "file.hpp"
+
+namespace vt {
+
+template <class A, class B>
+void Compare(A lhs, B rhs) {
+  std::optional<vt::file_exception> lhs_ex;
+  std::optional<vt::file_exception> rhs_ex;
+
+  try {
+    lhs();
+  } catch (const vt::file_exception& e) {
+    lhs_ex = vt::file_exception(e.code()) << e.what();
+  }
+
+  try {
+    rhs();
+  } catch (const vt::file_exception& e) {
+    rhs_ex = vt::file_exception(e.code()) << e.what();
+  }
+
+  if (lhs_ex && !rhs_ex) {
+    throw vt::cmp_file_exception() << "(FAIL, OK): " << lhs_ex->what();
+  }
+  if (!lhs_ex && rhs_ex) {
+    throw vt::cmp_file_exception() << "(OK, FAIL): " << rhs_ex->what();
+  }
+  if (lhs_ex && rhs_ex && lhs_ex->code() != rhs_ex->code()) {
+    throw vt::cmp_file_exception()
+        << "(FAIL, FAIL), but codes differ: " << lhs_ex->what() << ", "
+        << rhs_ex->what();
+  }
+}
+
+cmp_file::cmp_file(std::unique_ptr<file> lhs, std::unique_ptr<file> rhs)
+    : lhs_(std::move(lhs)), rhs_(std::move(rhs)) {
+}
+
+auto cmp_file::read(char* buffer, size_t count) -> void {
+  Compare(
+      [buffer, count, this] { lhs_->read(buffer, count); },
+      [buffer, count, this] { lhs_->read(buffer, count); }
+  );
+}
+
+auto cmp_file::write(const char* buffer, size_t count) -> void {
+  Compare(
+      [buffer, count, this] { lhs_->write(buffer, count); },
+      [buffer, count, this] { lhs_->write(buffer, count); }
+  );
+}
+
+auto cmp_file::seek(off_t offset) -> void {
+  Compare(
+      [offset, this] { lhs_->seek(offset); },
+      [offset, this] { lhs_->seek(offset); }
+  );
+}
+
+auto cmp_file::sync() -> void {
+  Compare([this] { lhs_->sync(); }, [this] { rhs_->sync(); });
+}
+
+}  // namespace vt
diff --git a/lab/vtpc/test/lib/cmp_file.hpp b/lab/vtpc/test/lib/cmp_file.hpp
new file mode 100644
index 0000000..506480e
--- /dev/null
+++ b/lab/vtpc/test/lib/cmp_file.hpp
@@ -0,0 +1,24 @@
+#pragma once
+
+#include "file.hpp"
+
+namespace vt {
+
+class cmp_file_exception : public vt::exception {};
+
+class cmp_file final : public file {
+public:
+  cmp_file(std::unique_ptr<file> lhs, std::unique_ptr<file> rhs);
+  ~cmp_file() override = default;
+
+  auto read(char* buffer, size_t count) -> void override;
+  auto write(const char* buffer, size_t count) -> void override;
+  auto seek(off_t offset) -> void override;
+  auto sync() -> void override;
+
+private:
+  std::unique_ptr<file> lhs_;
+  std::unique_ptr<file> rhs_;
+};
+
+}  // namespace vt
diff --git a/lab/vtpc/test/lib/exception.cpp b/lab/vtpc/test/lib/exception.cpp
new file mode 100644
index 0000000..a3a2978
--- /dev/null
+++ b/lab/vtpc/test/lib/exception.cpp
@@ -0,0 +1 @@
+#include "exception.hpp"
diff --git a/lab/vtpc/test/lib/exception.hpp b/lab/vtpc/test/lib/exception.hpp
new file mode 100644
index 0000000..407e16d
--- /dev/null
+++ b/lab/vtpc/test/lib/exception.hpp
@@ -0,0 +1,34 @@
+#pragma once
+
+#include <exception>
+#include <sstream>
+
+namespace vt {
+
+class exception : public std::exception {
+public:
+  exception() = default;
+
+  auto what() const noexcept -> const char* override {
+    message_ = buffer_.str();
+    return message_.c_str();
+  }
+
+  template <class T>
+  inline void Append(const T& t) {
+    buffer_ << t;
+  }
+
+private:
+  mutable std::stringstream buffer_;
+  mutable std::string message_;
+};
+
+template <class E, class T>
+static inline auto operator<<(E&& e [[clang::lifetimebound]], const T& t)
+    -> std::enable_if_t<std::is_base_of_v<exception, std::decay_t<E>>, E&&> {
+  e.Append(t);
+  return std::forward<E>(e);
+}
+
+}  // namespace vt
\ No newline at end of file
diff --git a/lab/vtpc/test/lib/file.cpp b/lab/vtpc/test/lib/file.cpp
new file mode 100644
index 0000000..7a23393
--- /dev/null
+++ b/lab/vtpc/test/lib/file.cpp
@@ -0,0 +1,123 @@
+#include "file.hpp"
+
+#include <cstddef>
+#include <functional>
+#include <memory>
+#include <string_view>
+#include <utility>
+
+#include "exception.hpp"
+
+extern "C" {
+#include "fcntl.h"
+#include "unistd.h"
+#include "vtpc.h"
+}
+
+namespace vt {
+
+constexpr auto flags = O_RDWR | O_CREAT;
+
+file_exception::file_exception(ssize_t code) : code_(code) {
+  (*this) << "code " << code << ": ";
+}
+
+auto file_exception::code() const -> ssize_t {
+  return code_;
+}
+
+struct io {
+  std::function<int(const char* path, int mode)> open;
+  std::function<int(int fd)> close;
+  std::function<ssize_t(int fd, void* buf, size_t count)> read;
+  std::function<ssize_t(int fd, const void* buf, size_t count)> write;
+  std::function<off_t(int fd, off_t offset, int whence)> lseek;
+  std::function<int(int fd)> fsync;
+};
+
+template <class A>
+void robust_do(A action, int fd, auto buf, size_t count) {
+  size_t total = 0;
+  while (total < count) {
+    ssize_t local = action(fd, buf, count);
+    if (local < 0) {
+      throw vt::file_exception(local)
+          << "failed to read/write " << count << "bytes from file with fd "
+          << fd << ": " << strerror(errno);  // NOLINT(concurrency-mt-unsafe);
+    }
+
+    total += local;
+  }
+}
+
+class io_file final : public file {
+public:
+  explicit io_file(std::string_view path, io io)
+      : fd_(io.open(path.data(), flags)), io_(std::move(io)) {
+    if (fd_ < 0) {
+      throw vt::file_exception(fd_)
+          << "failed to open file '" << path << "'"
+          << ": " << strerror(errno);  // NOLINT(concurrency-mt-unsafe);
+    }
+  }
+
+  ~io_file() override {
+    (void)io_.close(fd_);
+  }
+
+  void read(char* buffer, size_t count) override {
+    robust_do(io_.read, fd_, buffer, count);
+  }
+
+  void write(const char* buffer, size_t count) override {
+    robust_do(io_.write, fd_, buffer, count);
+  }
+
+  void seek(off_t offset) override {
+    if (io_.lseek(fd_, offset, SEEK_SET) == -1) {
+      throw vt::file_exception(-1)
+          << "failed to seek to offset " << offset << "file with fd " << fd_
+          << ": " << strerror(errno);  // NOLINT(concurrency-mt-unsafe)
+    }
+  }
+
+  void sync() override {
+    if (io_.fsync(fd_) == -1) {
+      throw vt::file_exception(-1)
+          << "failed to fsync file with fd " << fd_ << ": "
+          << strerror(errno);  // NOLINT(concurrency-mt-unsafe)
+    }
+  }
+
+private:
+  int fd_;
+  io io_;
+};
+
+auto file::open_libc(std::string_view path) -> std::unique_ptr<file> {
+  io io = {
+      .open = ::open,
+      .close = ::close,
+      .read = ::read,
+      .write = ::write,
+      .lseek = ::lseek,
+      .fsync = ::fsync,
+  };
+
+  return std::make_unique<io_file>(path, std::move(io));
+}
+
+auto file::open_vtpc(std::string_view path) -> std::unique_ptr<file> {
+  io io = {
+      .open = ::vtpc_open,
+      .close = ::vtpc_close,
+      .read = ::vtpc_read,
+      .write = ::vtpc_write,
+      .lseek = ::vtpc_lseek,
+      .fsync = ::vtpc_fsync,
+  };
+
+  return std::make_unique<io_file>(path, std::move(io));
+}
+
+}  // namespace vt
diff --git a/lab/vtpc/test/lib/file.hpp b/lab/vtpc/test/lib/file.hpp
new file mode 100644
index 0000000..f0f0d45
--- /dev/null
+++ b/lab/vtpc/test/lib/file.hpp
@@ -0,0 +1,33 @@
+#pragma once
+
+#include <cstddef>
+#include <memory>
+#include <string_view>
+
+#include "exception.hpp"
+
+namespace vt {
+
+class file_exception : public vt::exception {
+public:
+  explicit file_exception(ssize_t code);
+
+  auto code() const -> ssize_t;
+
+private:
+  ssize_t code_;
+};
+
+class file {
+public:
+  virtual ~file() = default;
+  virtual auto read(char* buffer, size_t count) -> void = 0;
+  virtual auto write(const char* buffer, size_t count) -> void = 0;
+  virtual auto seek(off_t offset) -> void = 0;
+  virtual auto sync() -> void = 0;
+
+  static auto open_libc(std::string_view path) -> std::unique_ptr<file>;
+  static auto open_vtpc(std::string_view path) -> std::unique_ptr<file>;
+};
+
+}  // namespace vt
diff --git a/lab/vtpc/test/test_basic.cpp b/lab/vtpc/test/test_basic.cpp
new file mode 100644
index 0000000..2dd0071
--- /dev/null
+++ b/lab/vtpc/test/test_basic.cpp
@@ -0,0 +1,33 @@
+#include <exception>
+#include <iostream>
+#include <memory>
+
+#include "cmp_file.hpp"
+#include "file.hpp"
+
+auto write(vt::file& file, std::string_view text) -> void {
+  file.write(text.data(), text.size());
+}
+
+auto read(vt::file& file, size_t size) -> std::string {
+  std::string text(size, 0);
+  file.read(text.data(), size);
+  return text;
+}
+
+auto main() -> int try {
+  auto libc = vt::file::open_libc("/tmp/a");
+  auto vtpc = vt::file::open_vtpc("/tmp/b");
+  vt::cmp_file cmp(std::move(libc), std::move(vtpc));
+
+  std::string_view message = "Hello, World!";
+  write(cmp, message);
+  cmp.sync();
+  cmp.seek(0);
+  std::cout << read(cmp, message.size()) << '\n';
+
+  return 0;
+} catch (const std::exception& e) {
+  std::cerr << "exception: " << e.what() << '\n';
+  return 1;
+}

From 1a4ce699bfc18e62aa0fe2884cec1384400f61e6 Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 10:39:31 +0300
Subject: [PATCH 02/13] Fix issues (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/lib/vtpc.c            |  4 ++--
 lab/vtpc/lib/vtpc.h            |  2 +-
 lab/vtpc/test/lib/cmp_file.cpp | 21 ++++++++++++---------
 lab/vtpc/test/lib/file.cpp     |  5 +++--
 4 files changed, 18 insertions(+), 14 deletions(-)

diff --git a/lab/vtpc/lib/vtpc.c b/lab/vtpc/lib/vtpc.c
index 3b678bd..a85829e 100644
--- a/lab/vtpc/lib/vtpc.c
+++ b/lab/vtpc/lib/vtpc.c
@@ -3,8 +3,8 @@
 #include <fcntl.h>
 #include <unistd.h>
 
-int vtpc_open(const char* path, int mode) {
-  return open(path, mode);
+int vtpc_open(const char* path, int mode, int access) {
+  return open(path, mode, access);
 }
 
 int vtpc_close(int fd) {
diff --git a/lab/vtpc/lib/vtpc.h b/lab/vtpc/lib/vtpc.h
index fa817e2..2d4bd40 100644
--- a/lab/vtpc/lib/vtpc.h
+++ b/lab/vtpc/lib/vtpc.h
@@ -2,7 +2,7 @@
 
 #include <sys/types.h>
 
-int vtpc_open(const char* path, int mode);
+int vtpc_open(const char* path, int mode, int access);
 int vtpc_close(int fd);
 ssize_t vtpc_read(int fd, void* buf, size_t count);
 ssize_t vtpc_write(int fd, const void* buf, size_t count);
diff --git a/lab/vtpc/test/lib/cmp_file.cpp b/lab/vtpc/test/lib/cmp_file.cpp
index 99221e3..4d02ef9 100644
--- a/lab/vtpc/test/lib/cmp_file.cpp
+++ b/lab/vtpc/test/lib/cmp_file.cpp
@@ -1,3 +1,4 @@
+
 #include "cmp_file.hpp"
 
 #include <optional>
@@ -42,28 +43,30 @@ cmp_file::cmp_file(std::unique_ptr<file> lhs, std::unique_ptr<file> rhs)
 }
 
 auto cmp_file::read(char* buffer, size_t count) -> void {
+  std::string lhs(count, ' ');
+  std::string rhs(count, ' ');
   Compare(
-      [buffer, count, this] { lhs_->read(buffer, count); },
-      [buffer, count, this] { lhs_->read(buffer, count); }
+      [&] { lhs_->read(lhs.data(), count); },
+      [&] { rhs_->read(rhs.data(), count); }
   );
+  if (lhs != rhs) {
+    throw vt::cmp_file_exception() << "'" << lhs << "' != '" << rhs << "'";
+  }
+  std::memcpy(buffer, lhs.data(), count);
 }
 
 auto cmp_file::write(const char* buffer, size_t count) -> void {
   Compare(
-      [buffer, count, this] { lhs_->write(buffer, count); },
-      [buffer, count, this] { lhs_->write(buffer, count); }
+      [&] { lhs_->write(buffer, count); }, [&] { rhs_->write(buffer, count); }
   );
 }
 
 auto cmp_file::seek(off_t offset) -> void {
-  Compare(
-      [offset, this] { lhs_->seek(offset); },
-      [offset, this] { lhs_->seek(offset); }
-  );
+  Compare([&] { lhs_->seek(offset); }, [&] { rhs_->seek(offset); });
 }
 
 auto cmp_file::sync() -> void {
-  Compare([this] { lhs_->sync(); }, [this] { rhs_->sync(); });
+  Compare([&] { lhs_->sync(); }, [this] { rhs_->sync(); });
 }
 
 }  // namespace vt
diff --git a/lab/vtpc/test/lib/file.cpp b/lab/vtpc/test/lib/file.cpp
index 7a23393..a3dee36 100644
--- a/lab/vtpc/test/lib/file.cpp
+++ b/lab/vtpc/test/lib/file.cpp
@@ -17,6 +17,7 @@ extern "C" {
 namespace vt {
 
 constexpr auto flags = O_RDWR | O_CREAT;
+constexpr auto access = 0777;
 
 file_exception::file_exception(ssize_t code) : code_(code) {
   (*this) << "code " << code << ": ";
@@ -27,7 +28,7 @@ auto file_exception::code() const -> ssize_t {
 }
 
 struct io {
-  std::function<int(const char* path, int mode)> open;
+  std::function<int(const char* path, int mode, int access)> open;
   std::function<int(int fd)> close;
   std::function<ssize_t(int fd, void* buf, size_t count)> read;
   std::function<ssize_t(int fd, const void* buf, size_t count)> write;
@@ -53,7 +54,7 @@ void robust_do(A action, int fd, auto buf, size_t count) {
 class io_file final : public file {
 public:
   explicit io_file(std::string_view path, io io)
-      : fd_(io.open(path.data(), flags)), io_(std::move(io)) {
+      : fd_(io.open(path.data(), flags, access)), io_(std::move(io)) {
     if (fd_ < 0) {
       throw vt::file_exception(fd_)
           << "failed to open file '" << path << "'"

From f817d7ff682b5cecdfee811706065353a15c3bc4 Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 10:43:32 +0300
Subject: [PATCH 03/13] Add convinience (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/test/lib/cmp_file.hpp |  3 +++
 lab/vtpc/test/lib/file.hpp     | 10 ++++++++++
 lab/vtpc/test/test_basic.cpp   | 14 ++------------
 3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/lab/vtpc/test/lib/cmp_file.hpp b/lab/vtpc/test/lib/cmp_file.hpp
index 506480e..77b97a8 100644
--- a/lab/vtpc/test/lib/cmp_file.hpp
+++ b/lab/vtpc/test/lib/cmp_file.hpp
@@ -8,6 +8,9 @@ class cmp_file_exception : public vt::exception {};
 
 class cmp_file final : public file {
 public:
+  using file::write;
+  using file::read;
+
   cmp_file(std::unique_ptr<file> lhs, std::unique_ptr<file> rhs);
   ~cmp_file() override = default;
 
diff --git a/lab/vtpc/test/lib/file.hpp b/lab/vtpc/test/lib/file.hpp
index f0f0d45..376d6e1 100644
--- a/lab/vtpc/test/lib/file.hpp
+++ b/lab/vtpc/test/lib/file.hpp
@@ -26,6 +26,16 @@ class file {
   virtual auto seek(off_t offset) -> void = 0;
   virtual auto sync() -> void = 0;
 
+  auto write(std::string_view text) -> void {
+    return write(text.data(), text.size());
+  }
+
+  auto read(size_t size) -> std::string {
+    std::string text(size, 0);
+    read(text.data(), size);
+    return text;
+  }
+
   static auto open_libc(std::string_view path) -> std::unique_ptr<file>;
   static auto open_vtpc(std::string_view path) -> std::unique_ptr<file>;
 };
diff --git a/lab/vtpc/test/test_basic.cpp b/lab/vtpc/test/test_basic.cpp
index 2dd0071..edaf7f3 100644
--- a/lab/vtpc/test/test_basic.cpp
+++ b/lab/vtpc/test/test_basic.cpp
@@ -5,26 +5,16 @@
 #include "cmp_file.hpp"
 #include "file.hpp"
 
-auto write(vt::file& file, std::string_view text) -> void {
-  file.write(text.data(), text.size());
-}
-
-auto read(vt::file& file, size_t size) -> std::string {
-  std::string text(size, 0);
-  file.read(text.data(), size);
-  return text;
-}
-
 auto main() -> int try {
   auto libc = vt::file::open_libc("/tmp/a");
   auto vtpc = vt::file::open_vtpc("/tmp/b");
   vt::cmp_file cmp(std::move(libc), std::move(vtpc));
 
   std::string_view message = "Hello, World!";
-  write(cmp, message);
+  cmp.write(message);
   cmp.sync();
   cmp.seek(0);
-  std::cout << read(cmp, message.size()) << '\n';
+  std::cout << cmp.read(message.size()) << '\n';
 
   return 0;
 } catch (const std::exception& e) {

From 9959bfd0ae2ac3b9dbadfbb62757802facdc8b96 Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 11:20:28 +0300
Subject: [PATCH 04/13] Add seq test (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/test/CMakeLists.txt |  4 ++++
 lab/vtpc/test/test_seq.cpp   | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 40 insertions(+)
 create mode 100644 lab/vtpc/test/test_seq.cpp

diff --git a/lab/vtpc/test/CMakeLists.txt b/lab/vtpc/test/CMakeLists.txt
index 5136fb4..1a6d21a 100644
--- a/lab/vtpc/test/CMakeLists.txt
+++ b/lab/vtpc/test/CMakeLists.txt
@@ -7,3 +7,7 @@ add_subdirectory(lib)
 add_executable(test_basic test_basic.cpp)
 target_include_directories(test_basic PUBLIC .)
 target_link_libraries(test_basic PRIVATE vt)
+
+add_executable(test_seq test_seq.cpp)
+target_include_directories(test_seq PUBLIC .)
+target_link_libraries(test_seq PRIVATE vt)
diff --git a/lab/vtpc/test/test_seq.cpp b/lab/vtpc/test/test_seq.cpp
new file mode 100644
index 0000000..4ab68f6
--- /dev/null
+++ b/lab/vtpc/test/test_seq.cpp
@@ -0,0 +1,36 @@
+#include <exception>
+#include <iostream>
+#include <memory>
+
+#include "cmp_file.hpp"
+#include "file.hpp"
+
+auto main() -> int try {
+  constexpr size_t count = 1024;
+
+  auto libc = vt::file::open_libc("/tmp/a");
+  auto vtpc = vt::file::open_vtpc("/tmp/b");
+  vt::cmp_file cmp(std::move(libc), std::move(vtpc));
+
+  cmp.seek(0);
+  for (size_t i = 0; i < count; ++i) {
+    std::string text = std::to_string(i);
+    cmp.write(text);
+  }
+
+  cmp.seek(0);
+  for (size_t i = 0; i < count; ++i) {
+    std::string expected = std::to_string(i);
+    std::string actual = cmp.read(expected.size());
+    if (expected != actual) {
+      throw vt::exception() << "'" << expected << "' != '" << actual << "'";
+    }
+  }
+
+  cmp.sync();
+
+  return 0;
+} catch (const std::exception& e) {
+  std::cerr << "exception: " << e.what() << '\n';
+  return 1;
+}

From dbf5b0aac8631b7fbed03a4df1af4f94441e32e5 Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 13:35:07 +0300
Subject: [PATCH 05/13] Add random test (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/test/CMakeLists.txt     |  4 ++
 lab/vtpc/test/lib/CMakeLists.txt |  1 +
 lab/vtpc/test/lib/cmp_file.cpp   | 14 ++++---
 lab/vtpc/test/lib/cmp_file.hpp   |  2 +-
 lab/vtpc/test/lib/file.cpp       |  8 +++-
 lab/vtpc/test/lib/log_file.cpp   | 32 +++++++++++++++
 lab/vtpc/test/lib/log_file.hpp   | 24 +++++++++++
 lab/vtpc/test/test_random.cpp    | 70 ++++++++++++++++++++++++++++++++
 8 files changed, 147 insertions(+), 8 deletions(-)
 create mode 100644 lab/vtpc/test/lib/log_file.cpp
 create mode 100644 lab/vtpc/test/lib/log_file.hpp
 create mode 100644 lab/vtpc/test/test_random.cpp

diff --git a/lab/vtpc/test/CMakeLists.txt b/lab/vtpc/test/CMakeLists.txt
index 1a6d21a..4c59001 100644
--- a/lab/vtpc/test/CMakeLists.txt
+++ b/lab/vtpc/test/CMakeLists.txt
@@ -11,3 +11,7 @@ target_link_libraries(test_basic PRIVATE vt)
 add_executable(test_seq test_seq.cpp)
 target_include_directories(test_seq PUBLIC .)
 target_link_libraries(test_seq PRIVATE vt)
+
+add_executable(test_random test_random.cpp)
+target_include_directories(test_random PUBLIC .)
+target_link_libraries(test_random PRIVATE vt)
diff --git a/lab/vtpc/test/lib/CMakeLists.txt b/lab/vtpc/test/lib/CMakeLists.txt
index ec729a6..9aca5ff 100644
--- a/lab/vtpc/test/lib/CMakeLists.txt
+++ b/lab/vtpc/test/lib/CMakeLists.txt
@@ -4,6 +4,7 @@ add_library(
     cmp_file.cpp
     exception.cpp
     file.cpp
+    log_file.cpp
 )
 
 target_include_directories(vt PUBLIC .)
diff --git a/lab/vtpc/test/lib/cmp_file.cpp b/lab/vtpc/test/lib/cmp_file.cpp
index 4d02ef9..f740c2a 100644
--- a/lab/vtpc/test/lib/cmp_file.cpp
+++ b/lab/vtpc/test/lib/cmp_file.cpp
@@ -36,10 +36,14 @@ void Compare(A lhs, B rhs) {
         << "(FAIL, FAIL), but codes differ: " << lhs_ex->what() << ", "
         << rhs_ex->what();
   }
+  if (lhs_ex && rhs_ex) {
+    const vt::file_exception& e = *lhs_ex;
+    throw vt::file_exception(e.code()) << e.what();
+  }
 }
 
 cmp_file::cmp_file(std::unique_ptr<file> lhs, std::unique_ptr<file> rhs)
-    : lhs_(std::move(lhs)), rhs_(std::move(rhs)) {
+    : lhs_(std::move(lhs)), file_(std::move(rhs)) {
 }
 
 auto cmp_file::read(char* buffer, size_t count) -> void {
@@ -47,7 +51,7 @@ auto cmp_file::read(char* buffer, size_t count) -> void {
   std::string rhs(count, ' ');
   Compare(
       [&] { lhs_->read(lhs.data(), count); },
-      [&] { rhs_->read(rhs.data(), count); }
+      [&] { file_->read(rhs.data(), count); }
   );
   if (lhs != rhs) {
     throw vt::cmp_file_exception() << "'" << lhs << "' != '" << rhs << "'";
@@ -57,16 +61,16 @@ auto cmp_file::read(char* buffer, size_t count) -> void {
 
 auto cmp_file::write(const char* buffer, size_t count) -> void {
   Compare(
-      [&] { lhs_->write(buffer, count); }, [&] { rhs_->write(buffer, count); }
+      [&] { lhs_->write(buffer, count); }, [&] { file_->write(buffer, count); }
   );
 }
 
 auto cmp_file::seek(off_t offset) -> void {
-  Compare([&] { lhs_->seek(offset); }, [&] { rhs_->seek(offset); });
+  Compare([&] { lhs_->seek(offset); }, [&] { file_->seek(offset); });
 }
 
 auto cmp_file::sync() -> void {
-  Compare([&] { lhs_->sync(); }, [this] { rhs_->sync(); });
+  Compare([&] { lhs_->sync(); }, [this] { file_->sync(); });
 }
 
 }  // namespace vt
diff --git a/lab/vtpc/test/lib/cmp_file.hpp b/lab/vtpc/test/lib/cmp_file.hpp
index 77b97a8..7d79d10 100644
--- a/lab/vtpc/test/lib/cmp_file.hpp
+++ b/lab/vtpc/test/lib/cmp_file.hpp
@@ -21,7 +21,7 @@ class cmp_file final : public file {
 
 private:
   std::unique_ptr<file> lhs_;
-  std::unique_ptr<file> rhs_;
+  std::unique_ptr<file> file_;
 };
 
 }  // namespace vt
diff --git a/lab/vtpc/test/lib/file.cpp b/lab/vtpc/test/lib/file.cpp
index a3dee36..504e204 100644
--- a/lab/vtpc/test/lib/file.cpp
+++ b/lab/vtpc/test/lib/file.cpp
@@ -20,7 +20,6 @@ constexpr auto flags = O_RDWR | O_CREAT;
 constexpr auto access = 0777;
 
 file_exception::file_exception(ssize_t code) : code_(code) {
-  (*this) << "code " << code << ": ";
 }
 
 auto file_exception::code() const -> ssize_t {
@@ -43,9 +42,14 @@ void robust_do(A action, int fd, auto buf, size_t count) {
     ssize_t local = action(fd, buf, count);
     if (local < 0) {
       throw vt::file_exception(local)
-          << "failed to read/write " << count << "bytes from file with fd "
+          << "failed to read/write " << count << " bytes from file with fd "
           << fd << ": " << strerror(errno);  // NOLINT(concurrency-mt-unsafe);
     }
+    if (local == 0) {
+      throw vt::file_exception(0) << "failed to read/write " << count
+                                  << " bytes from file with fd " << fd << ": "
+                                  << "EOF after reading " << total << " bytes";
+    }
 
     total += local;
   }
diff --git a/lab/vtpc/test/lib/log_file.cpp b/lab/vtpc/test/lib/log_file.cpp
new file mode 100644
index 0000000..afc0730
--- /dev/null
+++ b/lab/vtpc/test/lib/log_file.cpp
@@ -0,0 +1,32 @@
+#include "log_file.hpp"
+
+#include <iostream>
+
+#include "file.hpp"
+
+namespace vt {
+
+log_file::log_file(std::unique_ptr<file> file) : file_(std::move(file)) {
+}
+
+auto log_file::read(char* buffer, size_t count) -> void {
+  std::cerr << "[vt] read count " << count << "\n";
+  file_->read(buffer, count);
+}
+
+auto log_file::write(const char* buffer, size_t count) -> void {
+  std::cerr << "[vt] write count " << count << "\n";
+  file_->write(buffer, count);
+}
+
+auto log_file::seek(off_t offset) -> void {
+  std::cerr << "[vt] seek offset " << offset << "\n";
+  file_->seek(offset);
+}
+
+auto log_file::sync() -> void {
+  std::cerr << "[vt] sync\n";
+  file_->sync();
+}
+
+}  // namespace vt
diff --git a/lab/vtpc/test/lib/log_file.hpp b/lab/vtpc/test/lib/log_file.hpp
new file mode 100644
index 0000000..c999bc8
--- /dev/null
+++ b/lab/vtpc/test/lib/log_file.hpp
@@ -0,0 +1,24 @@
+#pragma once
+
+#include "file.hpp"
+
+namespace vt {
+
+class log_file final : public file {
+public:
+  using file::write;
+  using file::read;
+
+  explicit log_file(std::unique_ptr<file> file);
+  ~log_file() override = default;
+
+  auto read(char* buffer, size_t count) -> void override;
+  auto write(const char* buffer, size_t count) -> void override;
+  auto seek(off_t offset) -> void override;
+  auto sync() -> void override;
+
+private:
+  std::unique_ptr<file> file_;
+};
+
+}  // namespace vt
diff --git a/lab/vtpc/test/test_random.cpp b/lab/vtpc/test/test_random.cpp
new file mode 100644
index 0000000..1129f81
--- /dev/null
+++ b/lab/vtpc/test/test_random.cpp
@@ -0,0 +1,70 @@
+#include <exception>
+#include <iostream>
+#include <memory>
+#include <random>
+
+#include "cmp_file.hpp"
+#include "file.hpp"
+#include "log_file.hpp"
+
+auto main() -> int try {
+  constexpr size_t seed = 1;
+  constexpr size_t steps = (1U << 16U);
+  constexpr size_t size = (1U << 12U);
+  constexpr size_t interval = 100;
+
+  std::unique_ptr<vt::file> file = [] {
+    auto libc = vt::file::open_libc("/tmp/a");
+    auto vtpc = vt::file::open_vtpc("/tmp/b");
+    auto cmp = std::make_unique<vt::cmp_file>(std::move(libc), std::move(vtpc));
+    auto log = std::make_unique<vt::log_file>(std::move(cmp));
+    return log;
+  }();
+
+  std::default_random_engine random(seed);  // NOLINT
+
+  std::uniform_int_distribution<size_t> action_dist(0, 100);  // NOLINT
+  std::uniform_int_distribution<off_t> offset_dist(0, size);
+  std::uniform_int_distribution<size_t> batch_dist(0, size / 4);
+  std::uniform_int_distribution<uint8_t> char_dist(0);
+
+  const auto random_string = [&](size_t size) {
+    std::string string(size, ' ');
+    for (char& c : string) {
+      c = static_cast<char>(char_dist(random));
+    }
+    return string;
+  };
+
+  file->seek(0);
+  file->write(std::string(size, ' '));
+
+  file->seek(0);
+  for (size_t i = 0; i < steps; ++i) {
+    if (i % interval == 0) {
+      std::cerr << "i = " << i << '\n';
+    }
+
+    try {
+      size_t point = action_dist(random);
+      if (point < 40) {  // NOLINT
+        size_t batch = batch_dist(random);
+        file->read(batch);
+      } else if (point < 75) {  // NOLINT
+        size_t batch = batch_dist(random);
+        file->write(random_string(batch));
+      } else if (point < 95) {  // NOLINT
+        file->seek(offset_dist(random));
+      } else {
+        file->sync();
+      }
+    } catch (vt::file_exception& e) {  // NOLINT
+      // Do nothing
+    }
+  }
+
+  return 0;
+} catch (const std::exception& e) {
+  std::cerr << "exception: " << e.what() << '\n';
+  return 1;
+}

From c631283f98bb3da3e2222b03c1afc32fa0b5c3db Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 13:38:49 +0300
Subject: [PATCH 06/13] Add GitHub Flow (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 .github/workflows/vtpc.yml | 51 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)
 create mode 100644 .github/workflows/vtpc.yml

diff --git a/.github/workflows/vtpc.yml b/.github/workflows/vtpc.yml
new file mode 100644
index 0000000..933788f
--- /dev/null
+++ b/.github/workflows/vtpc.yml
@@ -0,0 +1,51 @@
+name: Test VT Page Cache
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    paths:
+      - 'lab/vtpc/**'
+
+jobs:
+  build:
+    strategy:
+      matrix:
+        cmake_build_type:
+          - Asan
+          - Release
+    runs-on: ubuntu-latest
+    container:
+      image: silkeh/clang:latest
+    defaults:
+      run:
+        working-directory: ./lab/vtpc
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Clang Format
+        run: |
+          find . -path ./build -prune -o \( -iname '*.c' -o -iname '*.h' -o -iname '*.cpp' -o -iname '*.hpp' \) -exec \
+            clang-format --style=file --dry-run --verbose {} \;
+
+      - name: Configure
+        run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.cmake_build_type }}
+
+      - name: Build
+        run: cmake --build build
+
+      - name: Clang Tidy
+        run: |
+          find . -path ./build -prune -o \( -iname '*.c' -o -iname '*.h' -o -iname '*.cpp' -o -iname '*.hpp' \) -exec \
+            clang-tidy -p . {} \;
+
+      - name: Test Basic
+        run: ./build/test/test_basic
+
+      - name: Test Sequential
+        run: ./build/test/test_seq
+
+      - name: Test Random
+        run: ./build/test/test_random

From 1aee6a5b48c1a587fb4ee5ca38a91a70e6b5580b Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 13:40:31 +0300
Subject: [PATCH 07/13] Fix build (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/test/lib/cmp_file.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lab/vtpc/test/lib/cmp_file.cpp b/lab/vtpc/test/lib/cmp_file.cpp
index f740c2a..bbb04a6 100644
--- a/lab/vtpc/test/lib/cmp_file.cpp
+++ b/lab/vtpc/test/lib/cmp_file.cpp
@@ -56,7 +56,7 @@ auto cmp_file::read(char* buffer, size_t count) -> void {
   if (lhs != rhs) {
     throw vt::cmp_file_exception() << "'" << lhs << "' != '" << rhs << "'";
   }
-  std::memcpy(buffer, lhs.data(), count);
+  memcpy(buffer, lhs.data(), count);
 }
 
 auto cmp_file::write(const char* buffer, size_t count) -> void {

From 0126386392a895cab8ac54fe25cbc2a456d8c012 Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 13:42:07 +0300
Subject: [PATCH 08/13] Format (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/test/lib/cmp_file.cpp | 1 -
 lab/vtpc/test/lib/cmp_file.hpp | 2 +-
 lab/vtpc/test/lib/log_file.hpp | 2 +-
 3 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/lab/vtpc/test/lib/cmp_file.cpp b/lab/vtpc/test/lib/cmp_file.cpp
index bbb04a6..adb3fa7 100644
--- a/lab/vtpc/test/lib/cmp_file.cpp
+++ b/lab/vtpc/test/lib/cmp_file.cpp
@@ -1,4 +1,3 @@
-
 #include "cmp_file.hpp"
 
 #include <optional>
diff --git a/lab/vtpc/test/lib/cmp_file.hpp b/lab/vtpc/test/lib/cmp_file.hpp
index 7d79d10..5b8d121 100644
--- a/lab/vtpc/test/lib/cmp_file.hpp
+++ b/lab/vtpc/test/lib/cmp_file.hpp
@@ -8,8 +8,8 @@ class cmp_file_exception : public vt::exception {};
 
 class cmp_file final : public file {
 public:
-  using file::write;
   using file::read;
+  using file::write;
 
   cmp_file(std::unique_ptr<file> lhs, std::unique_ptr<file> rhs);
   ~cmp_file() override = default;
diff --git a/lab/vtpc/test/lib/log_file.hpp b/lab/vtpc/test/lib/log_file.hpp
index c999bc8..53ab6dc 100644
--- a/lab/vtpc/test/lib/log_file.hpp
+++ b/lab/vtpc/test/lib/log_file.hpp
@@ -6,8 +6,8 @@ namespace vt {
 
 class log_file final : public file {
 public:
-  using file::write;
   using file::read;
+  using file::write;
 
   explicit log_file(std::unique_ptr<file> file);
   ~log_file() override = default;

From bd2bdd542dcefcff2ed558e2fbe63dc9a963e39b Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 13:44:02 +0300
Subject: [PATCH 09/13] Fix build (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/test/lib/cmp_file.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lab/vtpc/test/lib/cmp_file.cpp b/lab/vtpc/test/lib/cmp_file.cpp
index adb3fa7..d3dafe3 100644
--- a/lab/vtpc/test/lib/cmp_file.cpp
+++ b/lab/vtpc/test/lib/cmp_file.cpp
@@ -1,6 +1,7 @@
 #include "cmp_file.hpp"
 
 #include <optional>
+#include <cstring>
 
 #include "exception.hpp"
 #include "file.hpp"

From 407b09149d717854e343f9a5ea907ccbdb1a1170 Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 13:45:32 +0300
Subject: [PATCH 10/13] Fix build (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/test/lib/file.cpp | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lab/vtpc/test/lib/file.cpp b/lab/vtpc/test/lib/file.cpp
index 504e204..ff33c89 100644
--- a/lab/vtpc/test/lib/file.cpp
+++ b/lab/vtpc/test/lib/file.cpp
@@ -1,6 +1,7 @@
 #include "file.hpp"
 
 #include <cstddef>
+#include <cstring>
 #include <functional>
 #include <memory>
 #include <string_view>

From a193eed53618f9a88e6d80adc6956eb7a52d10ac Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 14:01:21 +0300
Subject: [PATCH 11/13] Fix style (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 lab/vtpc/.clang-tidy            |  1 +
 lab/vtpc/compile_commands.json  | 50 +++++++++++++++++++++++++++++++++
 lab/vtpc/test/lib/cmp_file.cpp  |  2 +-
 lab/vtpc/test/lib/cmp_file.hpp  |  1 +
 lab/vtpc/test/lib/exception.hpp |  3 +-
 lab/vtpc/test/lib/file.hpp      |  2 +-
 6 files changed, 56 insertions(+), 3 deletions(-)
 create mode 100644 lab/vtpc/compile_commands.json

diff --git a/lab/vtpc/.clang-tidy b/lab/vtpc/.clang-tidy
index 07e1c89..6cdbcfb 100644
--- a/lab/vtpc/.clang-tidy
+++ b/lab/vtpc/.clang-tidy
@@ -15,6 +15,7 @@ Checks: |
     modernize-*,
     performance-*,
     portability-*,
+    -portability-avoid-pragma-once,
     readability-*
     -readability-identifier-length
 WarningsAsErrors: '*'
diff --git a/lab/vtpc/compile_commands.json b/lab/vtpc/compile_commands.json
new file mode 100644
index 0000000..093a2f6
--- /dev/null
+++ b/lab/vtpc/compile_commands.json
@@ -0,0 +1,50 @@
+[
+{
+  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/lib",
+  "command": "/usr/bin/cc  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/.  -arch arm64 -o CMakeFiles/vtpc.dir/vtpc.c.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/vtpc.c",
+  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/vtpc.c",
+  "output": "lib/CMakeFiles/vtpc.dir/vtpc.c.o"
+},
+{
+  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test",
+  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -std=c++2b -arch arm64 -o CMakeFiles/test_basic.dir/test_basic.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_basic.cpp",
+  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_basic.cpp",
+  "output": "test/CMakeFiles/test_basic.dir/test_basic.cpp.o"
+},
+{
+  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test",
+  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -std=c++2b -arch arm64 -o CMakeFiles/test_seq.dir/test_seq.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_seq.cpp",
+  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_seq.cpp",
+  "output": "test/CMakeFiles/test_seq.dir/test_seq.cpp.o"
+},
+{
+  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test",
+  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -std=c++2b -arch arm64 -o CMakeFiles/test_random.dir/test_random.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_random.cpp",
+  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_random.cpp",
+  "output": "test/CMakeFiles/test_random.dir/test_random.cpp.o"
+},
+{
+  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test/lib",
+  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/. -std=c++2b -arch arm64 -o CMakeFiles/vt.dir/cmp_file.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/cmp_file.cpp",
+  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/cmp_file.cpp",
+  "output": "test/lib/CMakeFiles/vt.dir/cmp_file.cpp.o"
+},
+{
+  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test/lib",
+  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/. -std=c++2b -arch arm64 -o CMakeFiles/vt.dir/exception.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/exception.cpp",
+  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/exception.cpp",
+  "output": "test/lib/CMakeFiles/vt.dir/exception.cpp.o"
+},
+{
+  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test/lib",
+  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/. -std=c++2b -arch arm64 -o CMakeFiles/vt.dir/file.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/file.cpp",
+  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/file.cpp",
+  "output": "test/lib/CMakeFiles/vt.dir/file.cpp.o"
+},
+{
+  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test/lib",
+  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/. -std=c++2b -arch arm64 -o CMakeFiles/vt.dir/log_file.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/log_file.cpp",
+  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/log_file.cpp",
+  "output": "test/lib/CMakeFiles/vt.dir/log_file.cpp.o"
+}
+]
\ No newline at end of file
diff --git a/lab/vtpc/test/lib/cmp_file.cpp b/lab/vtpc/test/lib/cmp_file.cpp
index d3dafe3..d24fe6e 100644
--- a/lab/vtpc/test/lib/cmp_file.cpp
+++ b/lab/vtpc/test/lib/cmp_file.cpp
@@ -1,7 +1,7 @@
 #include "cmp_file.hpp"
 
-#include <optional>
 #include <cstring>
+#include <optional>
 
 #include "exception.hpp"
 #include "file.hpp"
diff --git a/lab/vtpc/test/lib/cmp_file.hpp b/lab/vtpc/test/lib/cmp_file.hpp
index 5b8d121..1454cd7 100644
--- a/lab/vtpc/test/lib/cmp_file.hpp
+++ b/lab/vtpc/test/lib/cmp_file.hpp
@@ -1,5 +1,6 @@
 #pragma once
 
+#include "exception.hpp"
 #include "file.hpp"
 
 namespace vt {
diff --git a/lab/vtpc/test/lib/exception.hpp b/lab/vtpc/test/lib/exception.hpp
index 407e16d..d0cde05 100644
--- a/lab/vtpc/test/lib/exception.hpp
+++ b/lab/vtpc/test/lib/exception.hpp
@@ -9,13 +9,14 @@ class exception : public std::exception {
 public:
   exception() = default;
 
+  [[nodiscard]]
   auto what() const noexcept -> const char* override {
     message_ = buffer_.str();
     return message_.c_str();
   }
 
   template <class T>
-  inline void Append(const T& t) {
+  void Append(const T& t) {
     buffer_ << t;
   }
 
diff --git a/lab/vtpc/test/lib/file.hpp b/lab/vtpc/test/lib/file.hpp
index 376d6e1..28ea1c5 100644
--- a/lab/vtpc/test/lib/file.hpp
+++ b/lab/vtpc/test/lib/file.hpp
@@ -12,7 +12,7 @@ class file_exception : public vt::exception {
 public:
   explicit file_exception(ssize_t code);
 
-  auto code() const -> ssize_t;
+  [[nodiscard]] auto code() const -> ssize_t;
 
 private:
   ssize_t code_;

From b970881d1e8862c1347fbaa3232f9f2450d8faea Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 15:15:12 +0300
Subject: [PATCH 12/13] What? (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 .github/workflows/vtpc.yml     |  2 +-
 .github/workflows/vtsh.yml     |  2 +-
 lab/vtpc/compile_commands.json | 50 ----------------------------------
 3 files changed, 2 insertions(+), 52 deletions(-)
 delete mode 100644 lab/vtpc/compile_commands.json

diff --git a/.github/workflows/vtpc.yml b/.github/workflows/vtpc.yml
index 933788f..6cf950a 100644
--- a/.github/workflows/vtpc.yml
+++ b/.github/workflows/vtpc.yml
@@ -39,7 +39,7 @@ jobs:
       - name: Clang Tidy
         run: |
           find . -path ./build -prune -o \( -iname '*.c' -o -iname '*.h' -o -iname '*.cpp' -o -iname '*.hpp' \) -exec \
-            clang-tidy -p . {} \;
+            clang-tidy -p ./build {} \;
 
       - name: Test Basic
         run: ./build/test/test_basic
diff --git a/.github/workflows/vtsh.yml b/.github/workflows/vtsh.yml
index c1ec7cf..a0304ce 100644
--- a/.github/workflows/vtsh.yml
+++ b/.github/workflows/vtsh.yml
@@ -39,7 +39,7 @@ jobs:
       - name: Clang Tidy
         run: |
           find . -path ./build -prune -o \( -iname '*.c' -o -iname '*.h' \) -exec \
-            clang-tidy -p . {} \;
+            clang-tidy -p ./build {} \;
 
       - name: Test
         working-directory: ./lab/vtsh/test
diff --git a/lab/vtpc/compile_commands.json b/lab/vtpc/compile_commands.json
deleted file mode 100644
index 093a2f6..0000000
--- a/lab/vtpc/compile_commands.json
+++ /dev/null
@@ -1,50 +0,0 @@
-[
-{
-  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/lib",
-  "command": "/usr/bin/cc  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/.  -arch arm64 -o CMakeFiles/vtpc.dir/vtpc.c.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/vtpc.c",
-  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/vtpc.c",
-  "output": "lib/CMakeFiles/vtpc.dir/vtpc.c.o"
-},
-{
-  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test",
-  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -std=c++2b -arch arm64 -o CMakeFiles/test_basic.dir/test_basic.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_basic.cpp",
-  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_basic.cpp",
-  "output": "test/CMakeFiles/test_basic.dir/test_basic.cpp.o"
-},
-{
-  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test",
-  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -std=c++2b -arch arm64 -o CMakeFiles/test_seq.dir/test_seq.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_seq.cpp",
-  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_seq.cpp",
-  "output": "test/CMakeFiles/test_seq.dir/test_seq.cpp.o"
-},
-{
-  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test",
-  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -std=c++2b -arch arm64 -o CMakeFiles/test_random.dir/test_random.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_random.cpp",
-  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/test_random.cpp",
-  "output": "test/CMakeFiles/test_random.dir/test_random.cpp.o"
-},
-{
-  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test/lib",
-  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/. -std=c++2b -arch arm64 -o CMakeFiles/vt.dir/cmp_file.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/cmp_file.cpp",
-  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/cmp_file.cpp",
-  "output": "test/lib/CMakeFiles/vt.dir/cmp_file.cpp.o"
-},
-{
-  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test/lib",
-  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/. -std=c++2b -arch arm64 -o CMakeFiles/vt.dir/exception.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/exception.cpp",
-  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/exception.cpp",
-  "output": "test/lib/CMakeFiles/vt.dir/exception.cpp.o"
-},
-{
-  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test/lib",
-  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/. -std=c++2b -arch arm64 -o CMakeFiles/vt.dir/file.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/file.cpp",
-  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/file.cpp",
-  "output": "test/lib/CMakeFiles/vt.dir/file.cpp.o"
-},
-{
-  "directory": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/build/test/lib",
-  "command": "/usr/bin/c++  -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/. -I/Users/vitya-smirnov/itmo/os-course/lab/vtpc/lib/. -std=c++2b -arch arm64 -o CMakeFiles/vt.dir/log_file.cpp.o -c /Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/log_file.cpp",
-  "file": "/Users/vitya-smirnov/itmo/os-course/lab/vtpc/test/lib/log_file.cpp",
-  "output": "test/lib/CMakeFiles/vt.dir/log_file.cpp.o"
-}
-]
\ No newline at end of file

From 31ec6a603d107dbb6fb6edbdf5a8932571e6210c Mon Sep 17 00:00:00 2001
From: vityaman <vityaman.dev@yandex.ru>
Date: Sun, 31 Aug 2025 12:49:19 +0000
Subject: [PATCH 13/13] Style (#8)

Signed-off-by: vityaman <vityaman.dev@yandex.ru>
---
 .github/workflows/vtpc.yml      |  9 ++++++---
 .github/workflows/vtsh.yml      |  9 ++++++---
 lab/vtpc/lib/vtpc.c             |  2 ++
 lab/vtpc/test/lib/cmp_file.cpp  |  6 ++++++
 lab/vtpc/test/lib/cmp_file.hpp  |  5 +++++
 lab/vtpc/test/lib/exception.cpp |  2 +-
 lab/vtpc/test/lib/exception.hpp |  5 +++--
 lab/vtpc/test/lib/file.cpp      | 20 ++++++++++++--------
 lab/vtpc/test/lib/file.hpp      |  5 ++++-
 lab/vtpc/test/lib/log_file.cpp  |  5 +++++
 lab/vtpc/test/lib/log_file.hpp  |  5 +++++
 lab/vtpc/test/test_basic.cpp    |  1 +
 lab/vtpc/test/test_random.cpp   |  6 ++++++
 lab/vtpc/test/test_seq.cpp      |  3 +++
 14 files changed, 65 insertions(+), 18 deletions(-)

diff --git a/.github/workflows/vtpc.yml b/.github/workflows/vtpc.yml
index 6cf950a..979f74e 100644
--- a/.github/workflows/vtpc.yml
+++ b/.github/workflows/vtpc.yml
@@ -27,8 +27,9 @@ jobs:
 
       - name: Clang Format
         run: |
-          find . -path ./build -prune -o \( -iname '*.c' -o -iname '*.h' -o -iname '*.cpp' -o -iname '*.hpp' \) -exec \
-            clang-format --style=file --dry-run --verbose {} \;
+          find . -path ./build -prune -o \
+            \( -iname '*.c' -o -iname '*.h' -o -iname '*.cpp' -o -iname '*.hpp' \) \
+            -exec clang-format --style=file --dry-run --verbose {} \;
 
       - name: Configure
         run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.cmake_build_type }}
@@ -37,8 +38,10 @@ jobs:
         run: cmake --build build
 
       - name: Clang Tidy
+        if: matrix.cmake_build_type == 'Release'
         run: |
-          find . -path ./build -prune -o \( -iname '*.c' -o -iname '*.h' -o -iname '*.cpp' -o -iname '*.hpp' \) -exec \
+          find . -path ./build -prune -o \
+            \( -iname '*.c' -o -iname '*.h' -o -iname '*.cpp' -o -iname '*.hpp' \) -exec \
             clang-tidy -p ./build {} \;
 
       - name: Test Basic
diff --git a/.github/workflows/vtsh.yml b/.github/workflows/vtsh.yml
index a0304ce..2fbfefe 100644
--- a/.github/workflows/vtsh.yml
+++ b/.github/workflows/vtsh.yml
@@ -27,8 +27,9 @@ jobs:
 
       - name: Clang Format
         run: |
-          find . -path ./build -prune -o \( -iname '*.c' -o -iname '*.h' \) -exec \
-            clang-format --style=file --dry-run --verbose {} \;
+          find . -path ./build -prune -o \
+            \( -iname '*.c' -o -iname '*.h' -o -iname '*.cpp' -o -iname '*.hpp' \) \
+            -exec clang-format --style=file --dry-run --verbose {} \;
 
       - name: Configure
         run: cmake -B build -DCMAKE_BUILD_TYPE=${{ matrix.cmake_build_type }}
@@ -37,8 +38,10 @@ jobs:
         run: cmake --build build
 
       - name: Clang Tidy
+        if: matrix.cmake_build_type == 'Release'
         run: |
-          find . -path ./build -prune -o \( -iname '*.c' -o -iname '*.h' \) -exec \
+          find . -path ./build -prune -o \
+            \( -iname '*.c' -o -iname '*.h' -o -iname '*.cpp' -o -iname '*.hpp' \) -exec \
             clang-tidy -p ./build {} \;
 
       - name: Test
diff --git a/lab/vtpc/lib/vtpc.c b/lab/vtpc/lib/vtpc.c
index a85829e..173ab1b 100644
--- a/lab/vtpc/lib/vtpc.c
+++ b/lab/vtpc/lib/vtpc.c
@@ -1,6 +1,8 @@
 #include "vtpc.h"
 
 #include <fcntl.h>
+#include <stddef.h>
+#include <sys/types.h>
 #include <unistd.h>
 
 int vtpc_open(const char* path, int mode, int access) {
diff --git a/lab/vtpc/test/lib/cmp_file.cpp b/lab/vtpc/test/lib/cmp_file.cpp
index d24fe6e..db42e63 100644
--- a/lab/vtpc/test/lib/cmp_file.cpp
+++ b/lab/vtpc/test/lib/cmp_file.cpp
@@ -1,7 +1,13 @@
 #include "cmp_file.hpp"
 
+#include <sys/types.h>
+
+#include <cstddef>
 #include <cstring>
+#include <memory>
 #include <optional>
+#include <string>
+#include <utility>
 
 #include "exception.hpp"
 #include "file.hpp"
diff --git a/lab/vtpc/test/lib/cmp_file.hpp b/lab/vtpc/test/lib/cmp_file.hpp
index 1454cd7..b984ae1 100644
--- a/lab/vtpc/test/lib/cmp_file.hpp
+++ b/lab/vtpc/test/lib/cmp_file.hpp
@@ -1,5 +1,10 @@
 #pragma once
 
+#include <sys/types.h>
+
+#include <cstddef>
+#include <memory>
+
 #include "exception.hpp"
 #include "file.hpp"
 
diff --git a/lab/vtpc/test/lib/exception.cpp b/lab/vtpc/test/lib/exception.cpp
index a3a2978..18042a1 100644
--- a/lab/vtpc/test/lib/exception.cpp
+++ b/lab/vtpc/test/lib/exception.cpp
@@ -1 +1 @@
-#include "exception.hpp"
+#include "exception.hpp"  // NOLINT
diff --git a/lab/vtpc/test/lib/exception.hpp b/lab/vtpc/test/lib/exception.hpp
index d0cde05..9dd8d6d 100644
--- a/lab/vtpc/test/lib/exception.hpp
+++ b/lab/vtpc/test/lib/exception.hpp
@@ -2,6 +2,7 @@
 
 #include <exception>
 #include <sstream>
+#include <type_traits>
 
 namespace vt {
 
@@ -26,8 +27,8 @@ class exception : public std::exception {
 };
 
 template <class E, class T>
-static inline auto operator<<(E&& e [[clang::lifetimebound]], const T& t)
-    -> std::enable_if_t<std::is_base_of_v<exception, std::decay_t<E>>, E&&> {
+  requires std::is_base_of_v<exception, std::decay_t<E>>
+static auto operator<<(E&& e [[clang::lifetimebound]], const T& t) -> E&& {
   e.Append(t);
   return std::forward<E>(e);
 }
diff --git a/lab/vtpc/test/lib/file.cpp b/lab/vtpc/test/lib/file.cpp
index ff33c89..dff8ed9 100644
--- a/lab/vtpc/test/lib/file.cpp
+++ b/lab/vtpc/test/lib/file.cpp
@@ -1,6 +1,8 @@
 #include "file.hpp"
 
+#include <cerrno>
 #include <cstddef>
+#include <cstdio>
 #include <cstring>
 #include <functional>
 #include <memory>
@@ -10,8 +12,10 @@
 #include "exception.hpp"
 
 extern "C" {
-#include "fcntl.h"
-#include "unistd.h"
+#include <fcntl.h>
+#include <sys/types.h>
+#include <unistd.h>
+
 #include "vtpc.h"
 }
 
@@ -40,16 +44,16 @@ template <class A>
 void robust_do(A action, int fd, auto buf, size_t count) {
   size_t total = 0;
   while (total < count) {
-    ssize_t local = action(fd, buf, count);
+    const ssize_t local = action(fd, buf, count);
     if (local < 0) {
       throw vt::file_exception(local)
           << "failed to read/write " << count << " bytes from file with fd "
           << fd << ": " << strerror(errno);  // NOLINT(concurrency-mt-unsafe);
     }
     if (local == 0) {
-      throw vt::file_exception(0) << "failed to read/write " << count
-                                  << " bytes from file with fd " << fd << ": "
-                                  << "EOF after reading " << total << " bytes";
+      throw vt::file_exception(0)
+          << "failed to read/write " << count << " bytes from file with fd "
+          << fd << ": " << "EOF after reading " << total << " bytes";
     }
 
     total += local;
@@ -62,8 +66,8 @@ class io_file final : public file {
       : fd_(io.open(path.data(), flags, access)), io_(std::move(io)) {
     if (fd_ < 0) {
       throw vt::file_exception(fd_)
-          << "failed to open file '" << path << "'"
-          << ": " << strerror(errno);  // NOLINT(concurrency-mt-unsafe);
+          << "failed to open file '" << path << "'" << ": "
+          << strerror(errno);  // NOLINT(concurrency-mt-unsafe);
     }
   }
 
diff --git a/lab/vtpc/test/lib/file.hpp b/lab/vtpc/test/lib/file.hpp
index 28ea1c5..378aedd 100644
--- a/lab/vtpc/test/lib/file.hpp
+++ b/lab/vtpc/test/lib/file.hpp
@@ -1,7 +1,10 @@
 #pragma once
 
+#include <sys/types.h>
+
 #include <cstddef>
 #include <memory>
+#include <string>
 #include <string_view>
 
 #include "exception.hpp"
@@ -27,7 +30,7 @@ class file {
   virtual auto sync() -> void = 0;
 
   auto write(std::string_view text) -> void {
-    return write(text.data(), text.size());
+    write(text.data(), text.size());
   }
 
   auto read(size_t size) -> std::string {
diff --git a/lab/vtpc/test/lib/log_file.cpp b/lab/vtpc/test/lib/log_file.cpp
index afc0730..499eca1 100644
--- a/lab/vtpc/test/lib/log_file.cpp
+++ b/lab/vtpc/test/lib/log_file.cpp
@@ -1,6 +1,11 @@
 #include "log_file.hpp"
 
+#include <sys/types.h>
+
+#include <cstddef>
 #include <iostream>
+#include <memory>
+#include <utility>
 
 #include "file.hpp"
 
diff --git a/lab/vtpc/test/lib/log_file.hpp b/lab/vtpc/test/lib/log_file.hpp
index 53ab6dc..d5c8aa9 100644
--- a/lab/vtpc/test/lib/log_file.hpp
+++ b/lab/vtpc/test/lib/log_file.hpp
@@ -1,5 +1,10 @@
 #pragma once
 
+#include <sys/types.h>
+
+#include <cstddef>
+#include <memory>
+
 #include "file.hpp"
 
 namespace vt {
diff --git a/lab/vtpc/test/test_basic.cpp b/lab/vtpc/test/test_basic.cpp
index edaf7f3..74c0855 100644
--- a/lab/vtpc/test/test_basic.cpp
+++ b/lab/vtpc/test/test_basic.cpp
@@ -1,6 +1,7 @@
 #include <exception>
 #include <iostream>
 #include <memory>
+#include <utility>
 
 #include "cmp_file.hpp"
 #include "file.hpp"
diff --git a/lab/vtpc/test/test_random.cpp b/lab/vtpc/test/test_random.cpp
index 1129f81..9d91208 100644
--- a/lab/vtpc/test/test_random.cpp
+++ b/lab/vtpc/test/test_random.cpp
@@ -1,7 +1,13 @@
+#include <sys/types.h>
+
+#include <cstddef>
+#include <cstdint>
 #include <exception>
 #include <iostream>
 #include <memory>
 #include <random>
+#include <string>
+#include <utility>
 
 #include "cmp_file.hpp"
 #include "file.hpp"
diff --git a/lab/vtpc/test/test_seq.cpp b/lab/vtpc/test/test_seq.cpp
index 4ab68f6..3aa417a 100644
--- a/lab/vtpc/test/test_seq.cpp
+++ b/lab/vtpc/test/test_seq.cpp
@@ -1,6 +1,9 @@
+#include <cstddef>
 #include <exception>
 #include <iostream>
 #include <memory>
+#include <string>
+#include <utility>
 
 #include "cmp_file.hpp"
 #include "file.hpp"