libc/test/src/unistd/ftruncate_test.cpp

   1 //===-- Unittests for ftruncate -------------------------------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "src/__support/CPP/string_view.h"
  10 #include "src/errno/libc_errno.h"
  11 #include "src/fcntl/open.h"
  12 #include "src/unistd/close.h"
  13 #include "src/unistd/ftruncate.h"
  14 #include "src/unistd/read.h"
  15 #include "src/unistd/unlink.h"
  16 #include "src/unistd/write.h"
  17 #include "test/UnitTest/ErrnoSetterMatcher.h"
  18 #include "test/UnitTest/Test.h"
  19
  20 namespace cpp = LIBC_NAMESPACE::cpp;
  21
  22 TEST(LlvmLibcFtruncateTest, CreateAndTruncate) {
  23   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
  24   constexpr const char TEST_FILE[] = "testdata/ftruncate.test";
  25   constexpr const char WRITE_DATA[] = "hello, ftruncate";
  26   constexpr size_t WRITE_SIZE = sizeof(WRITE_DATA);
  27   char buf[WRITE_SIZE];
  28
  29   // The test strategy is as follows:
  30   //   1. Create a normal file with some data in it.
  31   //   2. Read it to make sure what was written is actually in the file.
  32   //   3. Truncate to 1 byte.
  33   //   4. Try to read more than 1 byte and fail.
  34   libc_errno = 0;
  35   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
  36   ASSERT_EQ(libc_errno, 0);
  37   ASSERT_GT(fd, 0);
  38   ASSERT_EQ(ssize_t(WRITE_SIZE),
  39             LIBC_NAMESPACE::write(fd, WRITE_DATA, WRITE_SIZE));
  40   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
  41
  42   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
  43   ASSERT_EQ(libc_errno, 0);
  44   ASSERT_GT(fd, 0);
  45   ASSERT_EQ(ssize_t(WRITE_SIZE), LIBC_NAMESPACE::read(fd, buf, WRITE_SIZE));
  46   ASSERT_EQ(cpp::string_view(buf), cpp::string_view(WRITE_DATA));
  47   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
  48
  49   // For ftruncate operation to succeed, the file should be opened for
  50   // writing.
  51   fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY);
  52   ASSERT_GT(fd, 0);
  53   ASSERT_EQ(libc_errno, 0);
  54   ASSERT_THAT(LIBC_NAMESPACE::ftruncate(fd, off_t(1)), Succeeds(0));
  55   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
  56
  57   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
  58   ASSERT_EQ(libc_errno, 0);
  59   ASSERT_GT(fd, 0);
  60   ASSERT_EQ(ssize_t(1), LIBC_NAMESPACE::read(fd, buf, WRITE_SIZE));
  61   ASSERT_EQ(buf[0], WRITE_DATA[0]);
  62   ASSERT_THAT(LIBC_NAMESPACE::close(fd), Succeeds(0));
  63
  64   ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE), Succeeds(0));
  65 }
  66
  67 TEST(LlvmLibcFtruncateTest, TruncateBadFD) {
  68   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
  69   ASSERT_THAT(LIBC_NAMESPACE::ftruncate(1, off_t(1)), Fails(EINVAL));
  70 }