[v4,3/4] string: Add tests for strndup (BZ #30266)

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 | 222 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 223 insertions(+)
 create mode 100644 string/test-strndup.c

On 10/04/23 12:59, 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.

Some minor issues below.

> ---
>  string/Makefile       |   1 +
>  string/test-strndup.c | 222 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 223 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 \

Ok.

> diff --git a/string/test-strndup.c b/string/test-strndup.c
> new file mode 100644
> index 0000000000..b5665a3eec
> --- /dev/null
> +++ b/string/test-strndup.c
> @@ -0,0 +1,222 @@
> +/* 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 CHAR char
> +#define UCHAR unsigned char
> +#define BIG_CHAR CHAR_MAX
> +#define SMALL_CHAR 127
> +#define MEMSET memset
> +
> +
> +#ifndef STRNDUP_RESULT
> +# define STRNDUP_RESULT(dst, len, n) dst
> +# define TEST_MAIN
> +# define TEST_NAME "strndup"
> +# include "test-string.h"
> +
> +#endif /* !STRNDUP_RESULT */

Just remove these definitions and use the definitions directly.

> +
> +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);
> +}
> +
> +static void
> +do_test (size_t align1, size_t align2, size_t len, size_t n, int max_char)
> +{
> +  size_t i;
> +  CHAR *s1;
> +
> +/* For wcsndup: align1 and align2 here mean alignment not in bytes,
> +   but in wchar_ts, in bytes it will equal to align * (sizeof (wchar_t)).  */

This comment does not really apply (wcsndup does not exit).

> +  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;
Space after 'sizeof'.

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

No need to brackets for single line code.

> +
> +static void
> +do_random_tests (void)
> +{
> +  size_t i, j, n, align1, align2, len, size, mode;
> +  UCHAR *p1 = (UCHAR *) (buf1 + page_size) - 512;
> +  UCHAR *res;
> +
> +  for (n = 0; n < ITERATIONS; n++)
> +    {
> +      /* For wcsndup: align1 and align2 here mean align not in bytes,
> +	 but in wchar_ts, in bytes it will equal to align * (sizeof
> +	 (wchar_t)).  */

Same as before.

> +
> +      mode = random ();
> +      if (mode & 1)
> +	{
> +	  size = random () & 255;
> +	  align1 = 512 - size - (random () & 15);
> +	  if (mode & 2)
> +	    align2 = align1 - (random () & 24);
> +	  else
> +	    align2 = align1 - (random () & 31);
> +	  if (mode & 4)
> +	    {
> +	      j = align1;
> +	      align1 = align2;
> +	      align2 = j;
> +	    }
> +	  if (mode & 8)
> +	    len = size - (random () & 31);
> +	  else
> +	    len = 512;
> +	  if (len >= 512)
> +	    len = random () & 511;
> +	}
> +      else
> +	{
> +	  align1 = random () & 31;
> +	  if (mode & 2)
> +	    align2 = random () & 31;
> +	  else
> +	    align2 = align1 + (random () & 24);
> +	  len = random () & 511;
> +	  j = align1;
> +	  if (align2 > j)
> +	    j = align2;
> +	  if (mode & 4)
> +	    {
> +	      size = random () & 511;
> +	      if (size + j > 512)
> +		size = 512 - j - (random () & 31);
> +	    }
> +	  else
> +	    size = 512 - j;
> +	  if ((mode & 8) && len + j >= 512)
> +	    len = 512 - j - (random () & 7);
> +	}
> +      j = len + align1 + 64;
> +      if (j > 512)
> +	j = 512;
> +      for (i = 0; i < j; i++)
> +	{
> +	  if (i == len + align1)
> +	    p1[i] = 0;
> +	  else
> +	    {
> +	      p1[i] = random () & BIG_CHAR;
> +	      if (i >= align1 && i < len + align1 && !p1[i])
> +		p1[i] = (random () & SMALL_CHAR) + 3;
> +	    }
> +	}
> +
> +	res = (UCHAR *) strndup ((CHAR *) (p1 + align1), size);
> +	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", TEST_NAME);
> +  putchar ('\n');
> +
> +  for (i = 1; i < 8; ++i)
> +    {
> +      do_test (i, i, 16, 16, SMALL_CHAR);
> +      do_test (i, i, 16, 16, BIG_CHAR);
> +      do_test (i, 2 * i, 16, 16, SMALL_CHAR);
> +      do_test (2 * i, i, 16, 16, BIG_CHAR);
> +      do_test (8 - i, 2 * i, 1 << i, 2 << i, SMALL_CHAR);
> +      do_test (2 * i, 8 - i, 2 << i, 1 << i, SMALL_CHAR);
> +      do_test (8 - i, 2 * i, 1 << i, 2 << i, BIG_CHAR);
> +      do_test (2 * i, 8 - i, 2 << i, 1 << i, BIG_CHAR);
> +    }
> +
> +  for (i = 1; i < 8; ++i)
> +    {
> +      do_test (0, 0, 4 << i, 8 << i, SMALL_CHAR);
> +      do_test (0, 0, 16 << i, 8 << i, SMALL_CHAR);
> +      do_test (8 - i, 2 * i, 4 << i, 8 << i, SMALL_CHAR);
> +      do_test (8 - i, 2 * i, 16 << i, 8 << i, SMALL_CHAR);
> +    }
> +
> +  do_random_tests ();
> +  do_page_tests ();
> +  return ret;
> +}
> +
> +#include <support/test-driver.c>