zircon/system/ulib/fs-test-utils/include/fs-test-utils/fixture.h

// Copyright 2018 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file

#ifndef FS_TEST_UTILS_FIXTURE_H_
#define FS_TEST_UTILS_FIXTURE_H_

#include <lib/devmgr-integration-test/fixture.h>
#include <lib/devmgr-launcher/launch.h>
#include <lib/zx/time.h>
#include <stdint.h>
#include <stdio.h>
#include <unistd.h>
#include <zircon/status.h>
#include <zircon/syscalls.h>
#include <zircon/types.h>

#include <fbl/function.h>
#include <fbl/string.h>
#include <fbl/vector.h>
#include <fs-management/mount.h>
#include <ramdevice-client/ramdisk.h>

#include "src/storage/fvm/format.h"

// Macro for printing more information in error logs.
// "[File:Line] Error(error_name): Message\n"
#define LOG_ERROR(error_code, msg_fmt, ...)                          \
  fprintf(stderr, "[%s:%d] Error(%s): " msg_fmt, __FILE__, __LINE__, \
          zx_status_get_string(error_code), ##__VA_ARGS__)

// Macro for printing more information in stdout.
// "[File:Line] Info: Message\n"
#define LOG_INFO(msg_fmt, ...) \
  fprintf(stdout, "[%s:%d] Info: " msg_fmt, __FILE__, __LINE__, ##__VA_ARGS__)

namespace fs_test_utils {

constexpr size_t kPathSize = PATH_MAX;

constexpr size_t kFvmBlockSize = fvm::kBlockSize;

// TODO(gevalentno): when fxbug.dev/31875 is resolved, make MemFs setup and teardown
// part of the test fixture and remove RunWithMemFs.
// Workaround that provides a MemFs per process, since it cannot be unbinded
// from the process namespace yet.
int RunWithMemFs(const fbl::Function<int()>& main_fn);

// Available options for the test fixture.
//
// Note: use_ramdisk and block_device_path are mutually exclusive.
struct FixtureOptions {
  static FixtureOptions Default(disk_format_t format) {
    FixtureOptions options;
    options.use_ramdisk = true;
    options.ramdisk_block_size = 512;
    options.ramdisk_block_count = zx_system_get_physmem() / (2 * options.ramdisk_block_size);
    options.use_fvm = false;
    options.fvm_slice_size = kFvmBlockSize * (2 << 10);
    options.fs_type = format;
    options.seed = static_cast<unsigned int>(zx::ticks::now().get());
    options.isolated_devmgr = false;
    options.write_compression_algorithm = nullptr;
    return options;
  }

  // Returns true if the options are valid.
  // When invalid |err_string| will be populated with a human readable error description.
  bool IsValid(fbl::String* err_description) const;

  // Path to the block device to use.
  fbl::String block_device_path = "";

  // If true a ramdisk will be created and shared for the test.
  bool use_ramdisk = false;

  // Number of blocks the ramdisk will contain.
  size_t ramdisk_block_count = 0;

  // Size of the blocks the ramdisk will have.
  size_t ramdisk_block_size = 0;

  // If true an fvm will be mounted on the device, and the filesystem will be
  // mounted on top of a fresh partition.
  bool use_fvm = false;

  // Size of each slice of the created fvm.
  size_t fvm_slice_size = 0;

  // Type of filesystem to mount.
  disk_format_t fs_type;

  // Format the device device with the given |fs_type|. This is useful
  // when a test requires a block_device(and fvm) for tests.
  bool fs_format = true;

  // Mount the device in |Fixture::fs_path()|. Format is auto detected.
  bool fs_mount = true;

  // Seed for pseudo random number generator.
  unsigned int seed = 0;

  // Whether to use an isolated devmgr for each test.
  bool isolated_devmgr = false;

  // An optional compression algorithm specifier for the filesystem to use when storing files (if
  // the filesystem supports it).
  const char* write_compression_algorithm = nullptr;
};

// Provides a base fixture for File system tests.
// In main(a.k.a run_all_unittests):
//
// RunWithMemFs([argc, argv] () {  // Sets up then cleans up Local MemFs.
//   return run_all_unittests(argc, argv) ? 0: 1;
// }
class Fixture {
 public:
  Fixture() = delete;
  explicit Fixture(const FixtureOptions& options);
  Fixture(const Fixture&) = delete;
  Fixture(Fixture&&) = delete;
  Fixture& operator=(const Fixture&) = delete;
  Fixture& operator=(Fixture&&) = delete;
  ~Fixture();

  // Returns the options used by this fixture.
  const FixtureOptions& options() const { return options_; }

  // Returns the path to the block device hosting the FS.
  const fbl::String& block_device_path() const { return block_device_path_; }

  // Returns the path to the FVM partition created for the block device
  // hosting the FS. Will return empty if !options_.use_fvm.
  const fbl::String& partition_path() const { return partition_path_; }

  // Returns either the block_device path or partition_path if using fvm.
  const fbl::String& GetFsBlockDevice() const {
    return (options_.use_fvm) ? partition_path_ : block_device_path_;
  }

  // Returns the path where the filesystem was mounted.
  const fbl::String& fs_path() const { return fs_path_; }

  // Returns a seed to be used along the test, for rand_r calls.
  unsigned int* mutable_seed() { return &seed_; }

  // Unmounts the FS from fs_path.
  zx_status_t Umount();

  // Mounts the FsBlockDevice into fs_path.
  zx_status_t Mount();

  // Umounts and then Mounts the device.
  zx_status_t Remount() {
    zx_status_t res = Umount();
    if (res != ZX_OK) {
      return res;
    }
    res = Mount();
    return res;
  }

  // Checks the disk with fsck.
  zx_status_t Fsck() const;

  // Format (or reformat) the device.
  zx_status_t Format() const;

  // Sets up MemFs and Ramdisk, allocating resources for the tests.
  zx_status_t SetUpTestCase();

  // Formats the block device with the required type, creates a fvm, and mounts
  // the fs.
  zx_status_t SetUp();

  // Cleans up the block device by reformatting it, destroys the fvm and
  // unmounts the fs.
  zx_status_t TearDown();

  // Destroys the ramdisk, MemFs will die with the process. This should be
  // called after all tests finished execution to free resources.
  zx_status_t TearDownTestCase();

 private:
  FixtureOptions options_;

  // State of the resources allocated by the fixture.
  enum class ResourceState {
    kUnallocated,
    kAllocated,
    kFreed,
  };

  // The ramdisk, if it exists.
  ramdisk_client_t* ramdisk_ = nullptr;

  // Path to the block device hosting the mounted FS.
  fbl::String block_device_path_;

  // When using fvm, the FS will be mounted here.
  fbl::String partition_path_;

  // The root path where FS is mounted.
  fbl::String fs_path_;

  unsigned int seed_;

  // Keep track of the resource allocation during the setup teardown process,
  // to avoid leaks, or unnecessary errors when trying to free resources, that
  // may have never been allocated in first place.
  ResourceState fs_state_ = ResourceState::kUnallocated;
  ResourceState fvm_state_ = ResourceState::kUnallocated;
  ResourceState ramdisk_state_ = ResourceState::kUnallocated;

  // Isolated devmgr if requested.
  devmgr_integration_test::IsolatedDevmgr devmgr_;

  fbl::unique_fd devfs_root_;
  const char* root_path_;
};

}  // namespace fs_test_utils

#endif  // FS_TEST_UTILS_FIXTURE_H_