libc/test/src/sys/stat/fchmodat_test.cpp

//===-- Unittests for fchmodat --------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//

#include "hdr/errno_macros.h"
#include "hdr/fcntl_macros.h"
#include "hdr/sys_stat_macros.h"
#include "hdr/types/struct_stat.h"
#include "src/fcntl/open.h"
#include "src/sys/stat/fchmodat.h"
#include "src/unistd/close.h"
#include "src/unistd/write.h"
#include "test/UnitTest/ErrnoCheckingTest.h"
#include "test/UnitTest/ErrnoSetterMatcher.h"
#include "test/UnitTest/Test.h"

using namespace LIBC_NAMESPACE::testing::ErrnoSetterMatcher;
using LlvmLibcFchmodatTest = LIBC_NAMESPACE::testing::ErrnoCheckingTest;

TEST_F(LlvmLibcFchmodatTest, ChangeAndOpen) {
  // The test file is initially writable. We open it for writing and ensure
  // that it indeed can be opened for writing. Next, we close the file and
  // make it readonly using chmod. We test that chmod actually succeeded by
  // trying to open the file for writing and failing.
  constexpr const char *TEST_FILE = "testdata/fchmodat.test";
  constexpr const char *TEST_DIR = "testdata";
  constexpr const char *TEST_FILE_BASENAME = "fchmodat.test";
  const char WRITE_DATA[] = "fchmodat test";
  constexpr ssize_t WRITE_SIZE = ssize_t(sizeof(WRITE_DATA));

  int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_WRONLY, S_IRWXU);
  ASSERT_GT(fd, 0);
  ASSERT_ERRNO_SUCCESS();
  ASSERT_EQ(LIBC_NAMESPACE::write(fd, WRITE_DATA, sizeof(WRITE_DATA)),
            WRITE_SIZE);
  ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));

  int dirfd = LIBC_NAMESPACE::open(TEST_DIR, O_DIRECTORY);
  ASSERT_GT(dirfd, 0);
  ASSERT_ERRNO_SUCCESS();

  EXPECT_THAT(LIBC_NAMESPACE::fchmodat(dirfd, TEST_FILE_BASENAME, S_IRUSR, 0),
              Succeeds(0));

  // Opening for writing should fail.
  EXPECT_EQ(LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_WRONLY), -1);
  ASSERT_ERRNO_FAILURE();
  // But opening for reading should succeed.
  fd = LIBC_NAMESPACE::open(TEST_FILE, O_APPEND | O_RDONLY);
  EXPECT_GT(fd, 0);
  ASSERT_ERRNO_SUCCESS();

  EXPECT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
  EXPECT_THAT(LIBC_NAMESPACE::fchmodat(dirfd, TEST_FILE_BASENAME, S_IRWXU, 0),
              Succeeds(0));

  EXPECT_THAT(LIBC_NAMESPACE::close(dirfd), Succeeds(0));
}

TEST_F(LlvmLibcFchmodatTest, NonExistentFile) {
  ASSERT_THAT(
      LIBC_NAMESPACE::fchmodat(AT_FDCWD, "non-existent-file", S_IRUSR, 0),
      Fails(ENOENT));
}

TEST_F(LlvmLibcFchmodatTest, Flags) {
  constexpr const char *TEST_FILE = "testdata/fchmodat_flags.test";
  int fd = LIBC_NAMESPACE::open(TEST_FILE, O_CREAT | O_WRONLY, S_IRWXU);
  ASSERT_GT(fd, 0);
  ASSERT_ERRNO_SUCCESS();
  ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));

  int ret = LIBC_NAMESPACE::fchmodat(AT_FDCWD, TEST_FILE, S_IRUSR,
                                     AT_SYMLINK_NOFOLLOW);
  if (ret == 0) {
    // SYS_fchmodat2 is supported by the kernel.
    ASSERT_ERRNO_SUCCESS();
    ASSERT_THAT(LIBC_NAMESPACE::fchmodat(AT_FDCWD, "non-existent-file", S_IRUSR,
                                         AT_SYMLINK_NOFOLLOW),
                Fails(ENOENT));
    // Test AT_EMPTY_PATH on an open file descriptor.
    fd = LIBC_NAMESPACE::open(TEST_FILE, O_PATH);
    ASSERT_GT(fd, 0);
    ASSERT_ERRNO_SUCCESS();
    EXPECT_THAT(LIBC_NAMESPACE::fchmodat(fd, "", S_IRWXU, AT_EMPTY_PATH),
                Succeeds(0));
    ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));

    ASSERT_THAT(LIBC_NAMESPACE::fchmodat(AT_FDCWD, TEST_FILE, S_IRUSR, -1),
                Fails(EINVAL));
  } else {
    // Kernel or compile-time headers do not support fchmodat2; non-zero flags
    // fail with ENOTSUP.
    ASSERT_ERRNO_EQ(ENOTSUP);
    ASSERT_THAT(LIBC_NAMESPACE::fchmodat(AT_FDCWD, "non-existent-file", S_IRUSR,
                                         AT_SYMLINK_NOFOLLOW),
                Fails(ENOTSUP));
    ASSERT_THAT(
        LIBC_NAMESPACE::fchmodat(AT_FDCWD, TEST_FILE, S_IRUSR, AT_EMPTY_PATH),
        Fails(ENOTSUP));
    ASSERT_THAT(LIBC_NAMESPACE::fchmodat(AT_FDCWD, TEST_FILE, S_IRUSR, -1),
                Fails(ENOTSUP));
  }
}