/* Tests for copy_file_range.
   Copyright (C) 2017-2025 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <array_length.h>
#include <errno.h>
#include <fcntl.h>
#include <inttypes.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <support/check.h>
#include <support/support.h>
#include <support/temp_file.h>
#include <support/test-driver.h>
#include <support/xunistd.h>

/* Boolean flags which indicate whether to use pointers with explicit
   output flags.  */
static int do_inoff;
static int do_outoff;

/* Name and descriptors of the input files.  Files are truncated and
   reopened (with O_RDWR) between tests.  */
static char *infile;
static int infd;
static char *outfile;
static int outfd;

/* Input and output offsets.  Set according to do_inoff and do_outoff
   before the test.  The offsets themselves are always set to
   zero.  */
static off64_t inoff;
static off64_t *pinoff;
static off64_t outoff;
static off64_t *poutoff;

/* These are a collection of copy sizes used in tests.    */
enum { maximum_size = 99999 };
static const int typical_sizes[] =
  { 0, 1, 2, 3, 1024, 2048, 4096, 8191, 8192, 8193, maximum_size };

/* The random contents of this array can be used as a pattern to check
   for correct write operations.  */
static unsigned char random_data[maximum_size];

/* The size chosen by the test harness.  */
static int current_size;

/* Perform a copy of a file.  */
static void
simple_file_copy (void)
{
  xwrite (infd, random_data, current_size);

  int length;
  int in_skipped; /* Expected skipped bytes in input.  */
  if (do_inoff)
    {
      xlseek (infd, 1, SEEK_SET);
      inoff = 2;
      length = current_size - 3;
      in_skipped = 2;
    }
  else
    {
      xlseek (infd, 3, SEEK_SET);
      length = current_size - 5;
      in_skipped = 3;
    }
  int out_skipped; /* Expected skipped bytes before the written data.  */
  if (do_outoff)
    {
      xlseek (outfd, 4, SEEK_SET);
      outoff = 5;
      out_skipped = 5;
    }
  else
    {
      xlseek (outfd, 6, SEEK_SET);
      length = current_size - 6;
      out_skipped = 6;
    }
  if (length < 0)
    length = 0;

  TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                 length, 0), length);
  if (do_inoff)
    {
      TEST_COMPARE (inoff, 2 + length);
      TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 1);
    }
  else
    TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 3 + length);
  if (do_outoff)
    {
      TEST_COMPARE (outoff, 5 + length);
      TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 4);
    }
  else
    TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 6 + length);

  struct stat64 st;
  xfstat64 (outfd, &st);
  if (length > 0)
    TEST_COMPARE (st.st_size, out_skipped + length);
  else
    {
      /* If we did not write anything, we also did not add any
         padding.  */
      TEST_COMPARE (st.st_size, 0);
      return;
    }

  xlseek (outfd, 0, SEEK_SET);
  char *bytes = xmalloc (st.st_size);
  TEST_COMPARE (read (outfd, bytes, st.st_size), st.st_size);
  for (int i = 0; i < out_skipped; ++i)
    TEST_COMPARE (bytes[i], 0);
  TEST_VERIFY (memcmp (bytes + out_skipped, random_data + in_skipped,
                       length) == 0);
  free (bytes);
}

/* Test that a short input file results in a shortened copy.  */
static void
short_copy (void)
{
  if (current_size == 0)
    /* Nothing to shorten.  */
    return;

  /* Two subtests, one with offset 0 and current_size - 1 bytes, and
     another one with current_size bytes, but offset 1.  */
  for (int shift = 0; shift < 2; ++shift)
    {
      if (test_verbose > 0)
        printf ("info:   shift=%d\n", shift);
      xftruncate (infd, 0);
      xlseek (infd, 0, SEEK_SET);
      xwrite (infd, random_data, current_size - !shift);

      if (do_inoff)
        {
          inoff = shift;
          xlseek (infd, 2, SEEK_SET);
        }
      else
        {
          inoff = 3;
          xlseek (infd, shift, SEEK_SET);
        }
      xftruncate (outfd, 0);
      xlseek (outfd, 0, SEEK_SET);
      outoff = 0;

      /* First call copies current_size - 1 bytes.  */
      TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                     current_size, 0), current_size - 1);
      char *buffer = xmalloc (current_size);
      TEST_COMPARE (pread64 (outfd, buffer, current_size, 0),
                    current_size - 1);
      TEST_VERIFY (memcmp (buffer, random_data + shift, current_size - 1)
                   == 0);
      free (buffer);

      if (do_inoff)
        {
          TEST_COMPARE (inoff, current_size - 1 + shift);
          TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 2);
        }
      else
        TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), current_size - 1 + shift);
      if (do_outoff)
        {
          TEST_COMPARE (outoff, current_size - 1);
          TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 0);
        }
      else
        TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), current_size - 1);

      /* First call copies zero bytes.  */
      TEST_COMPARE (copy_file_range (infd, pinoff, outfd, poutoff,
                                     current_size, 0), 0);
      /* And the offsets are unchanged.  */
      if (do_inoff)
        {
          TEST_COMPARE (inoff, current_size - 1 + shift);
          TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), 2);
        }
      else
        TEST_COMPARE (xlseek (infd, 0, SEEK_CUR), current_size - 1 + shift);
      if (do_outoff)
        {
          TEST_COMPARE (outoff, current_size - 1);
          TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), 0);
        }
      else
        TEST_COMPARE (xlseek (outfd, 0, SEEK_CUR), current_size - 1);
    }
}

/* A named test function.  */
struct test_case
{
  const char *name;
  void (*func) (void);
  bool sizes; /* If true, call the test with different current_size values.  */
};

/* The available test cases.  */
static struct test_case tests[] =
  {
    { "simple_file_copy", simple_file_copy, .sizes = true },
    { "short_copy", short_copy, .sizes = true },
  };

static int
do_test (void)
{
  for (unsigned char *p = random_data; p < array_end (random_data); ++p)
    *p = rand () >> 24;

  infd = create_temp_file ("tst-copy_file_range-in-", &infile);
  outfd = create_temp_file ("tst-copy_file_range-out-", &outfile);
  {
    ssize_t ret = copy_file_range (infd, NULL, outfd, NULL, 0, 0);
    if (ret != 0)
      {
        if (errno == ENOSYS)
          FAIL_UNSUPPORTED ("copy_file_range is not support on this system");
        FAIL_EXIT1 ("copy_file_range probing call: %m");
      }
  }
  xclose (infd);
  xclose (outfd);

  for (do_inoff = 0; do_inoff < 2; ++do_inoff)
    for (do_outoff = 0; do_outoff < 2; ++do_outoff)
      for (struct test_case *test = tests; test < array_end (tests); ++test)
        for (const int *size = typical_sizes;
             size < array_end (typical_sizes); ++size)
          {
            current_size = *size;
            if (test_verbose > 0)
              printf ("info: %s do_inoff=%d do_outoff=%d current_size=%d\n",
                      test->name, do_inoff, do_outoff, current_size);

            inoff = 0;
            if (do_inoff)
              pinoff = &inoff;
            else
              pinoff = NULL;
            outoff = 0;
            if (do_outoff)
              poutoff = &outoff;
            else
              poutoff = NULL;

            infd = xopen (infile, O_RDWR | O_LARGEFILE, 0);
            xftruncate (infd, 0);
            outfd = xopen (outfile, O_RDWR | O_LARGEFILE, 0);
            xftruncate (outfd, 0);

            test->func ();

            xclose (infd);
            xclose (outfd);

            if (!test->sizes)
              /* Skip the other sizes unless they have been
                 requested.  */
              break;
          }

  free (infile);
  free (outfile);

  return 0;
}

#include <support/test-driver.c>