[v3,3/3] 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.
---
 string/Makefile       |   1 +
 string/test-strndup.c | 250 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 251 insertions(+)
 create mode 100644 string/test-strndup.c

On 04/04/23 16:00, 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.
> ---
>  string/Makefile       |   1 +
>  string/test-strndup.c | 250 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 251 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..a65373fa96
> --- /dev/null
> +++ b/string/test-strndup.c
> @@ -0,0 +1,250 @@
> +/* 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>
> +
> +#ifdef WIDE
> +# include <wchar.h>
> +# define CHAR wchar_t
> +# define UCHAR wchar_t
> +# define BIG_CHAR WCHAR_MAX
> +# define SMALL_CHAR 1273
> +# define MEMCMP wmemcmp
> +# define MEMSET wmemset
> +# define STRNLEN wcsnlen
> +#else
> +# define CHAR char
> +# define UCHAR unsigned char
> +# define BIG_CHAR CHAR_MAX
> +# define SMALL_CHAR 127
> +# define MEMCMP memcmp
> +# define MEMSET memset
> +# define STRNLEN strnlen
> +#endif /* !WIDE */
> +

We don't have wcsndup, so I think you can just simplify it to support 'char'.

> +
> +#ifndef STRNDUP_RESULT
> +# define STRNDUP_RESULT(dst, len, n) dst
> +# define TEST_MAIN
> +# ifndef WIDE
> +#  define TEST_NAME "strndup"
> +# else
> +#  define TEST_NAME "wcsndup"
> +# endif /* WIDE */
> +# include "test-string.h"
> +# ifndef WIDE
> +#  define STRNDUP strndup
> +# else
> +#  define STRNDUP wcsndup
> +# endif /* WIDE */
> +
> +#endif /* !STRNDUP_RESULT */
> +
> +typedef CHAR *(*proto_t) (const CHAR *, size_t);

There is no need of this typedef.

> +
> +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)).  */
> +  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).  */
> +
> +  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;
> +  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)).  */
> +
> +      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;
> +	if (MEMCMP (p1 + align1, res, j))
> +	  {
> +	    error (0, 0, "Iteration %zd - different strings, %s (%zd, %zd, %zd)",
> +	       n, "strndup", align1, align2, len);
> +	    ret = 1;
> +	  }
> +    }

You can use TEST_COMPARE_BLOB here:

   res = strndup ((CHAR *) (p1 + align1), size);
   TEST_COMPARE_BLOB (res, size, (CHAR *) (p1 + align1), size);
   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>