Re: [PATCH v5 3/4] string: Add tests for strndup (BZ #30266)

[Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>]

On 11/04/23 16:05, Joe Simmons-Talbott via Libc-alpha wrote:
> Copy strncpy tests for strndup.  Covers some basic testcases with random
> strings.  Remove tests that set the destination's bytes and checked the
> resulting buffer's bytes.  Remove wide character test support since
> wcsndup() doesn't exist.
> ---
>  string/Makefile       |   1 +
>  string/test-strndup.c | 200 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 201 insertions(+)
>  create mode 100644 string/test-strndup.c
> 
> diff --git a/string/Makefile b/string/Makefile
> index 472e318aea..2eef6f1dfc 100644
> --- a/string/Makefile
> +++ b/string/Makefile
> @@ -163,6 +163,7 @@ tests := \
>    test-strncat \
>    test-strncmp \
>    test-strncpy \
> +  test-strndup \
>    test-strnlen \
>    test-strpbrk \
>    test-strrchr \
> diff --git a/string/test-strndup.c b/string/test-strndup.c
> new file mode 100644
> index 0000000000..841145dc92
> --- /dev/null
> +++ b/string/test-strndup.c
> @@ -0,0 +1,200 @@
> +/* Test strndup functions.
> +   Copyright (C) 2023 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 <support/check.h>
> +
> +#define TEST_MAIN
> +#include "test-string.h"
> +
> +static void
> +do_one_test (const char *src, size_t len, size_t n)
> +{
> +  char *dst = strndup(src, n);
> +  size_t s = (len > n ? n: len) * sizeof (char);
> +
> +  TEST_COMPARE_BLOB(dst, s, src, s);

Missing space before '(' and also call free on the obtained result.

> +}
> +
> +static void
> +do_test (size_t align1, size_t align2, size_t len, size_t n, int max_char)
> +{
> +  size_t i;
> +  char *s1;
> +
> +  align1 &= 7;
> +  if ((align1 + len) * sizeof (char) >= page_size)
> +    return;
> +
> +  align2 &= 7;
> +  if ((align2 + len) * sizeof (char) >= page_size)
> +    return;
> +
> +  s1 = (char *) (buf1) + align1;
> +
> +  for (i = 0; i < len; ++i)
> +    s1[i] = 32 + 23 * i % (max_char - 32);
> +  s1[len] = 0;
> +  for (i = len + 1; (i + align1) * sizeof (char) < page_size && i < len + 64;
> +       ++i)
> +    s1[i] = 32 + 32 * i % (max_char - 32);
> +
> +  do_one_test (s1, len, n);
> +}
> +
> +static void
> +do_page_tests (void)
> +{
> +  char *s1;
> +  const size_t maxoffset = 64;
> +
> +  /* Put s1 at the maxoffset from the edge of buf1's last page.  */
> +  s1 = (char *) buf1 + BUF1PAGES * page_size / sizeof (char) - maxoffset;

> +  /* s2 needs room to put a string with size of maxoffset + 1 at s2 +
> +     (maxoffset - 1).  */

This comment does not apply on this test.

> +
> +  memset (s1, 'a', maxoffset - 1);
> +  s1[maxoffset - 1] = '\0';
> +
> +  /* Both strings are bounded to a page with read/write access and the next
> +     page is protected with PROT_NONE (meaning that any access outside of the
> +     page regions will trigger an invalid memory access).
> +
> +     The loop copies the string s1 for all possible offsets up to maxoffset
> +     for both inputs with a size larger than s1 (so memory access outside the
> +     expected memory regions might trigger invalid access).  */
> +
> +  for (size_t off1 = 0; off1 < maxoffset; off1++)
> +    for (size_t off2 = 0; off2 < maxoffset; off2++)
> +      do_one_test (s1 + off1, maxoffset - off1 - 1,
> +		   maxoffset + (maxoffset - off2));
> +}
> +
> +static void
> +do_random_tests (void)
> +{
> +  size_t i, j, n, align1, align2, len, size, mode;
> +  unsigned char *p1 = (unsigned char *) (buf1 + page_size) - 512;
> +  unsigned char *res;

Use 'char *' here, so you don't need to cast ...

> +
> +	res = (unsigned char *) strndup ((char *) (p1 + align1), size);

... here.

> +	j = len + 1;
> +	if (size < j)
> +	  j = size;
> +	TEST_COMPARE_BLOB (res, j, (char *) (p1 + align1), j);
> +	free (res);
> +    }
> +}
> +
> +int
> +test_main (void)
> +{
> +  size_t i;
> +
> +  test_init ();
> +
> +  printf ("%28s", "");
> +  printf ("\t%s", "strndup");
> +  putchar ('\n');
> +
> +  for (i = 1; i < 8; ++i)
> +    {
> +      do_test (i, i, 16, 16, 127);
> +      do_test (i, i, 16, 16, CHAR_MAX);
> +      do_test (i, 2 * i, 16, 16, 127);
> +      do_test (2 * i, i, 16, 16, CHAR_MAX);
> +      do_test (8 - i, 2 * i, 1 << i, 2 << i, 127);
> +      do_test (2 * i, 8 - i, 2 << i, 1 << i, 127);
> +      do_test (8 - i, 2 * i, 1 << i, 2 << i, CHAR_MAX);
> +      do_test (2 * i, 8 - i, 2 << i, 1 << i, CHAR_MAX);
> +    }
> +
> +  for (i = 1; i < 8; ++i)
> +    {
> +      do_test (0, 0, 4 << i, 8 << i, 127);
> +      do_test (0, 0, 16 << i, 8 << i, 127);
> +      do_test (8 - i, 2 * i, 4 << i, 8 << i, 127);
> +      do_test (8 - i, 2 * i, 16 << i, 8 << i, 127);
> +    }
> +
> +  do_random_tests ();
> +  do_page_tests ();
> +  return ret;
> +}
> +
> +#include <support/test-driver.c>

The rest looks ok.