libc/test/src/unistd/dup3_test.cpp

   1 //===-- Unittests for dup3 ------------------------------------------------===//
   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/errno/libc_errno.h"
  10 #include "src/fcntl/open.h"
  11 #include "src/unistd/close.h"
  12 #include "src/unistd/dup3.h"
  13 #include "src/unistd/read.h"
  14 #include "src/unistd/unlink.h"
  15 #include "src/unistd/write.h"
  16 #include "test/UnitTest/ErrnoSetterMatcher.h"
  17 #include "test/UnitTest/Test.h"
  18
  19 // The tests here are exactly the same as those of dup2. We only test the
  20 // plumbing of the dup3 syscall and not the dup3 functionality itself as it is
  21 // a simple syscall wrapper. Testing dup3 functionality is beyond the scope of
  22 // this test.
  23
  24 TEST(LlvmLibcdupTest, ReadAndWriteViaDup) {
  25   constexpr int DUPFD = 0xD0;
  26   libc_errno = 0;
  27   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
  28   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Succeeds;
  29   constexpr const char *TEST_FILE = "testdata/dup3.test";
  30   int fd = LIBC_NAMESPACE::open(TEST_FILE, O_WRONLY | O_CREAT, S_IRWXU);
  31   ASSERT_EQ(libc_errno, 0);
  32   ASSERT_GT(fd, 0);
  33   int dupfd = LIBC_NAMESPACE::dup3(fd, DUPFD, 0);
  34   ASSERT_EQ(libc_errno, 0);
  35   ASSERT_EQ(dupfd, DUPFD);
  36
  37   // Write something via the dup
  38   constexpr char WRITE_DATA[] = "Hello, dup!";
  39   constexpr size_t WRITE_SIZE = sizeof(WRITE_DATA);
  40   ASSERT_EQ(ssize_t(WRITE_SIZE),
  41             LIBC_NAMESPACE::write(dupfd, WRITE_DATA, WRITE_SIZE));
  42   ASSERT_THAT(LIBC_NAMESPACE::close(dupfd), Succeeds(0));
  43
  44   // Reopen the file for reading and create a dup.
  45   fd = LIBC_NAMESPACE::open(TEST_FILE, O_RDONLY);
  46   ASSERT_EQ(libc_errno, 0);
  47   ASSERT_GT(fd, 0);
  48   dupfd = LIBC_NAMESPACE::dup3(fd, DUPFD, 0);
  49   ASSERT_EQ(libc_errno, 0);
  50   ASSERT_EQ(dupfd, DUPFD);
  51
  52   // Read the file content via the dup.
  53   char buf[WRITE_SIZE];
  54   ASSERT_THAT(LIBC_NAMESPACE::read(dupfd, buf, WRITE_SIZE),
  55               Succeeds(WRITE_SIZE));
  56   ASSERT_STREQ(buf, WRITE_DATA);
  57
  58   // Verify that, unlike dup2, duping to the same fd value with dup3 fails.
  59   ASSERT_THAT(LIBC_NAMESPACE::dup3(dupfd, dupfd, 0), Fails(EINVAL));
  60
  61   ASSERT_THAT(LIBC_NAMESPACE::close(dupfd), Succeeds(0));
  62   ASSERT_THAT(LIBC_NAMESPACE::unlink(TEST_FILE), Succeeds(0));
  63 }
  64
  65 TEST(LlvmLibcdupTest, DupBadFD) {
  66   using LIBC_NAMESPACE::testing::ErrnoSetterMatcher::Fails;
  67   ASSERT_THAT(LIBC_NAMESPACE::dup3(-1, 123, 0), Fails(EBADF));
  68 }