[glibc] string: Add tests for strndup (BZ #30266)

[glibc] string: Add tests for strndup (BZ #30266)

[Adhemerval Zanella]

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=0c48aa0551151ea201f7f528492e89a0b08a6890

commit 0c48aa0551151ea201f7f528492e89a0b08a6890
Author: Joe Simmons-Talbott <josimmon@redhat.com>
Date:   Fri Apr 21 09:24:24 2023 -0400

    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.
    
    Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>

Diff:
---
 string/Makefile       |   1 +
 string/test-strndup.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 201 insertions(+)

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..7be0284e1c
--- /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);
+
+  free (dst);
+}
+
+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;
+
+  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;
+  char *p1 = (char *) (buf1 + page_size) - 512;
+  char *res;
+
+  for (n = 0; n < ITERATIONS; n++)
+    {
+      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 () & CHAR_MAX;
+	      if (i >= align1 && i < len + align1 && !p1[i])
+		p1[i] = (random () & 127) + 3;
+	    }
+	}
+
+	res = (char *) 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", "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>