This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] string: Additional test for strcmp, strcasecmp


On 07/07/2016 06:50 PM, Florian Weimer wrote:
On 07/07/2016 06:25 PM, Rajalakshmi Srinivasaraghavan wrote:


On 07/07/2016 09:46 PM, Florian Weimer wrote:
On 07/07/2016 06:06 PM, Rajalakshmi Srinivasaraghavan wrote:


On 07/05/2016 05:49 PM, Florian Weimer wrote:
2016-07-05  Florian Weimer <fweimer@redhat.com>

    * string/tst-cmp.c: New test.
    * string/Makefile (tests): Add it.

LGTM. Just one comment.

Thanks.

Can you include strncmp and strncasecmp as well?

What shall we do about the length argument?  Keep it constant at 64 or
something like that?

Either constant or strlen(left + left_align)+1.

That alters the result of the comparison.  We would have to use the
maximum over both string lengths, I think.

What about this?

Tested on aarch64, i386, ppc, ppc64, ppc64le, s390, s390x, x86_64 (some of the tests were run after loop switching, to avoid pointless reconstruction of the string).

The test runs rather long. I could remove the SIZE_MAX tests, some of the test strings, and a few of the pad byte choices to reduce the run time if that is desired.

Thanks,
Florian

string: More test for strcmp, strcasecmp, strncmp, strncasecmp

2016-07-08  Florian Weimer  <fweimer@redhat.com>

	* string/tst-cmp.c: New test.
	* string/Makefile (tests): Add it.

diff --git a/string/Makefile b/string/Makefile
index 9c87419..69d3f80 100644
--- a/string/Makefile
+++ b/string/Makefile
@@ -54,7 +54,7 @@ tests		:= tester inl-tester noinl-tester testcopy test-ffs	\
 		   tst-strtok tst-strxfrm bug-strcoll1 tst-strfry	\
 		   bug-strtok1 $(addprefix test-,$(strop-tests))	\
 		   bug-envz1 tst-strxfrm2 tst-endian tst-svc2		\
-		   tst-strtok_r bug-strcoll2
+		   tst-strtok_r bug-strcoll2 tst-cmp
 
 xtests = tst-strcoll-overflow
 
diff --git a/string/tst-cmp.c b/string/tst-cmp.c
new file mode 100644
index 0000000..c0f44f2
--- /dev/null
+++ b/string/tst-cmp.c
@@ -0,0 +1,213 @@
+/* Alignment/padding coverage test for string comparison.
+   Copyright (C) 2016 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
+   <http://www.gnu.org/licenses/>.  */
+
+/* This performs test comparisons with various (mis)alignments and
+   characters in the padding.  It is partly a regression test for bug
+   20327.  */
+
+#include <limits.h>
+#include <locale.h>
+#include <malloc.h>
+#include <stdbool.h>
+#include <stdlib.h>
+#include <string.h>
+
+static int
+signum (int val)
+{
+  if (val < 0)
+    return -1;
+  if (val > 0)
+    return 1;
+  else
+    return 0;
+}
+
+static size_t
+max_size_t (size_t left, size_t right)
+{
+  if (left > right)
+    return left;
+  else
+    return right;
+}
+
+/* Wrappers for strncmp and strncasecmp which determine the maximum
+   string length in some, either based on the input string length, or
+   using fixed constants.  */
+
+static int
+strncmp_no_terminator (const char *left, const char *right)
+{
+  size_t left_len = strlen (left);
+  size_t right_len = strlen (right);
+  return strncmp (left, right, max_size_t (left_len, right_len));
+}
+
+static int
+strncasecmp_no_terminator (const char *left, const char *right)
+{
+  size_t left_len = strlen (left);
+  size_t right_len = strlen (right);
+  return strncasecmp (left, right, max_size_t (left_len, right_len));
+}
+
+static int
+strncmp_terminator (const char *left, const char *right)
+{
+  size_t left_len = strlen (left);
+  size_t right_len = strlen (right);
+  return strncmp (left, right, max_size_t (left_len, right_len));
+}
+
+static int
+strncasecmp_terminator (const char *left, const char *right)
+{
+  size_t left_len = strlen (left);
+  size_t right_len = strlen (right);
+  return strncasecmp (left, right, max_size_t (left_len, right_len));
+}
+
+static int
+strncmp_64 (const char *left, const char *right)
+{
+  return strncmp (left, right, 64);
+}
+
+static int
+strncasecmp_64 (const char *left, const char *right)
+{
+  return strncasecmp (left, right, 64);
+}
+
+static int
+strncmp_max (const char *left, const char *right)
+{
+  return strncmp (left, right, SIZE_MAX);
+}
+
+static int
+strncasecmp_max (const char *left, const char *right)
+{
+  return strncasecmp (left, right, SIZE_MAX);
+}
+
+static int
+do_test (void)
+{
+  enum {
+    max_align = 64,
+    max_string_length = 33
+  };
+  size_t blob_size = max_align + max_string_length + 1;
+  char *left = memalign (max_align, blob_size);
+  char *right = memalign (max_align, blob_size);
+  if (left == NULL || right == NULL)
+    {
+      printf ("error: out of memory\n");
+      return 1;
+    }
+
+  const struct
+  {
+    const char *name;
+    int (*implementation) (const char *, const char *);
+  } functions[] =
+      {
+        { "strcmp", strcmp },
+        { "strcasecmp", strcasecmp },
+        { "strncmp (without NUL)", strncmp_no_terminator},
+        { "strncasecmp (without NUL)", strncasecmp_no_terminator},
+        { "strncmp (with NUL)", strncmp_terminator},
+        { "strncasecmp (with NUL)", strncasecmp_terminator},
+        { "strncmp (length 64)", strncmp_64},
+        { "strncasecmp (length 64)", strncasecmp_64},
+        { "strncmp (length SIZE_MAX)", strncmp_max},
+        { "strncasecmp (length SIZE_)MAX)", strncasecmp_max},
+        { NULL, NULL }
+      };
+  const char *const strings[] =
+    {
+      "",
+      "0",
+      "01",
+      "01234567",
+      "0123456789abcde",
+      "0123456789abcdef",
+      "0123456789abcdefg",
+      "1",
+      "10",
+      "123456789abcdef",
+      "123456789abcdefg",
+      "23456789abcdef",
+      "23456789abcdefg",
+      "abcdefghijklmnopqrstuvwxyzABCDEF",
+      NULL
+    };
+  const unsigned char pads[] =
+    { 0, 1, 32, 64, 128, '0', '1', 'e', 'f', 'g', 127, 192, 255 };
+
+  bool errors = false;
+  for (int left_idx = 0; strings[left_idx] != NULL; ++left_idx)
+    for (int left_align = 0; left_align < max_align; ++left_align)
+      for (unsigned pad_left = 0; pad_left < sizeof (pads); ++pad_left)
+        {
+          memset (left, pads[pad_left], blob_size);
+          strcpy (left + left_align, strings[left_idx]);
+
+          for (int right_idx = 0; strings[right_idx] != NULL; ++right_idx)
+            for (unsigned pad_right = 0; pad_right < sizeof (pads);
+                 ++pad_right)
+              for (int right_align = 0; right_align < max_align;
+                   ++right_align)
+                {
+                  memset (right, pads[pad_right], blob_size);
+                  strcpy (right + right_align, strings[right_idx]);
+
+                  for (int func = 0; functions[func].name != NULL; ++func)
+                    {
+                      int expected = left_idx - right_idx;
+                      int actual = functions[func].implementation
+                        (left + left_align, right + right_align);
+                      if (signum (actual) != signum (expected))
+                        {
+                          printf ("error: mismatch for %s: %d\n"
+                                  "  left:  \"%s\"\n"
+                                  "  right: \"%s\"\n"
+                                  "  pad_left = %u, pad_right = %u,\n"
+                                  "  left_align = %d, right_align = %d\n",
+                                  functions[func].name, actual,
+                                  strings[left_idx], strings[right_idx],
+                                  pad_left, pad_right,
+                                  left_align, right_align);
+                          errors = true;
+                        }
+                    }
+                }
+        }
+  free (right);
+  free (left);
+  return errors;
+}
+
+/* The nested loops need a long time to complete on slower
+   machines.  */
+#define TIMEOUT 300
+
+#define TEST_FUNCTION do_test ()
+#include "../test-skeleton.c"

Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]