Re: test-memchr failure on rawhide

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Re: test-memchr failure on rawhide

From:	Bruno Haible
Subject:	Re: test-memchr failure on rawhide
Date:	Wed, 13 May 2009 02:49:58 +0200
User-agent:	KMail/1.9.9
Jakub Jelinek, when closing the two reported glibc bugs, agreed with
our interpretation that a NULL pointer is an invalid argument to memchr
but a pointer to a zero-sized memory region is valid.

Here is a proposed patch to make the gnulib unit tests compliant,
without removing the particular test.

Opinions? Objections?


2009-05-12  Bruno Haible  <address@hidden>

        Make some tests ISO C 99 compliant.
        * tests/zerosize-ptr.h: New file.
        * tests/test-memchr.c: Include zerosize-ptr.h.
        (main): Use a zero-size object pointer instead of NULL.
        * tests/test-memchr2.c: Include zerosize-ptr.h.
        (main): Use a zero-size object pointer instead of NULL.
        * tests/test-memcmp.c: Include zerosize-ptr.h.
        (main): Use a zero-size object pointer instead of NULL.
        * tests/test-memmem.c: Include zerosize-ptr.h.
        (main): Use a zero-size object pointer instead of NULL.
        * tests/test-memrchr.c: Include zerosize-ptr.h.
        (main): Use a zero-size object pointer instead of NULL.
        * modules/memchr-tests (Files): Add tests/zerosize-ptr.h,
        m4/mmap-anon.m4.
        (Depends-on): Add getpagesize.
        (configure.ac): Invoke gl_FUNC_MMAP_ANON. Check for mprotect.
        * modules/memchr2-tests (Files): Add tests/zerosize-ptr.h,
        m4/mmap-anon.m4.
        (Depends-on): Add getpagesize.
        (configure.ac): Invoke gl_FUNC_MMAP_ANON. Check for mprotect.
        * modules/memcmp-tests (Files): Add tests/zerosize-ptr.h,
        m4/mmap-anon.m4.
        (Depends-on): Add getpagesize.
        (configure.ac): Invoke gl_FUNC_MMAP_ANON. Check for mprotect.
        * modules/memmem-tests (Files): Add tests/zerosize-ptr.h,
        m4/mmap-anon.m4.
        (Depends-on): Add getpagesize.
        (configure.ac): Invoke gl_FUNC_MMAP_ANON. Check for mprotect.
        * modules/memrchr-tests (Files): Add tests/zerosize-ptr.h,
        m4/mmap-anon.m4.
        (Depends-on): Add getpagesize.
        (configure.ac): Invoke gl_FUNC_MMAP_ANON. Check for mprotect.

============================= tests/zerosize-ptr.h =============================
/* Return a pointer to a zero-size object in memory.
   Copyright (C) 2009 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 3 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* ISO C 99 does not allow memcmp(), memchr() etc. to be invoked with a NULL
   argument.  Therefore this file produces a non-NULL pointer which cannot
   be dereferenced, if possible.  */

#include <stdlib.h>

#if HAVE_MPROTECT
# include <fcntl.h>
# include <unistd.h>
# include <sys/types.h>
# include <sys/mman.h>
/* Define MAP_FILE when it isn't otherwise.  */
# ifndef MAP_FILE
#  define MAP_FILE 0
# endif
#endif

/* Return a pointer to a zero-size object in memory, if possible.
   Return NULL otherwise.  */

static void *
zerosize_ptr (void)
{
/* Use mmap and mprotect when they exist.  Don't test HAVE_MMAP, because it is
   not defined on HP-UX 11 (since it does not support MAP_FIXED).  */
#if HAVE_MPROTECT
# if HAVE_MAP_ANONYMOUS
  const int flags = MAP_ANONYMOUS | MAP_PRIVATE;
  const int fd = -1;
# else /* !HAVE_MAP_ANONYMOUS */
  const int flags = MAP_FILE | MAP_PRIVATE;
  int fd = open ("/dev/zero", O_RDONLY, 0666);
  if (fd >= 0)
# endif
    {
      int pagesize = getpagesize ();
      char *two_pages =
        (char *) mmap (NULL, 2 * pagesize, PROT_READ | PROT_WRITE,
                       flags, fd, 0);
      if (two_pages != (char *)(-1)
          && mprotect (two_pages + pagesize, pagesize, PROT_NONE) == 0)
        return two_pages + pagesize;
    }
#endif
  return NULL;
}
================================================================================
--- tests/test-memchr.c.orig    2009-05-13 02:38:13.000000000 +0200
+++ tests/test-memchr.c 2009-05-13 01:24:29.000000000 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 Free Software Foundation
+ * Copyright (C) 2008-2009 Free Software Foundation
  * Written by Eric Blake and Bruno Haible
  *
  * This program is free software: you can redistribute it and/or modify
@@ -22,6 +22,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "zerosize-ptr.h"
+
 #define ASSERT(expr) \
   do                                                                        \
     {                                                                       \
@@ -41,8 +43,6 @@
 int
 main ()
 {
-  void *nil = NULL; /* Use to avoid gcc attribute((nonnull)) warnings.  */
-
   size_t n = 0x100000;
   char *input = malloc (n);
   ASSERT (input);
@@ -58,7 +58,7 @@
   ASSERT (MEMCHR (input, 'a', n) == input);
 
   ASSERT (MEMCHR (input, 'a', 0) == NULL);
-  ASSERT (MEMCHR (nil, 'a', 0) == NULL);
+  ASSERT (MEMCHR (zerosize_ptr (), 'a', 0) == NULL);
 
   ASSERT (MEMCHR (input, 'b', n) == input + 1);
   ASSERT (MEMCHR (input, 'c', n) == input + 2);
--- tests/test-memchr2.c.orig   2009-05-13 02:38:13.000000000 +0200
+++ tests/test-memchr2.c        2009-05-13 01:24:29.000000000 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 Free Software Foundation
+ * Copyright (C) 2008-2009 Free Software Foundation
  * Written by Eric Blake
  *
  * This program is free software: you can redistribute it and/or modify
@@ -23,6 +23,8 @@
 #include <stdlib.h>
 #include <string.h>
 
+#include "zerosize-ptr.h"
+
 #define ASSERT(expr) \
   do                                                                        \
     {                                                                       \
@@ -58,7 +60,7 @@
   ASSERT (MEMCHR2 (input, 'b', 'a', n) == input);
 
   ASSERT (MEMCHR2 (input, 'a', 'b', 0) == NULL);
-  ASSERT (MEMCHR2 (NULL, 'a', 'b', 0) == NULL);
+  ASSERT (MEMCHR2 (zerosize_ptr (), 'a', 'b', 0) == NULL);
 
   ASSERT (MEMCHR2 (input, 'b', 'd', n) == input + 1);
   ASSERT (MEMCHR2 (input + 2, 'b', 'd', n - 2) == input + 1026);
--- tests/test-memcmp.c.orig    2009-05-13 02:38:13.000000000 +0200
+++ tests/test-memcmp.c 2009-05-13 01:24:29.000000000 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 Free Software Foundation
+ * Copyright (C) 2008-2009 Free Software Foundation
  * Written by Simon Josefsson
  *
  * This program is free software: you can redistribute it and/or modify
@@ -22,6 +22,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "zerosize-ptr.h"
+
 #define ASSERT(expr) \
   do                                                                        \
     {                                                                       \
@@ -37,10 +39,8 @@
 int
 main (void)
 {
-  void *nil = NULL; /* Use to avoid gcc attribute((nonnull)) warnings.  */
-
   /* Test equal / not equal distinction.  */
-  ASSERT (memcmp (nil, nil, 0) == 0);
+  ASSERT (memcmp (zerosize_ptr (), zerosize_ptr (), 0) == 0);
   ASSERT (memcmp ("foo", "foobar", 2) == 0);
   ASSERT (memcmp ("foo", "foobar", 3) == 0);
   ASSERT (memcmp ("foo", "foobar", 4) != 0);
--- tests/test-memmem.c.orig    2009-05-13 02:38:13.000000000 +0200
+++ tests/test-memmem.c 2009-05-13 01:24:30.000000000 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2004, 2007, 2008 Free Software Foundation
+ * Copyright (C) 2004, 2007-2009 Free Software Foundation
  * Written by Bruno Haible and Eric Blake
  *
  * This program is free software: you can redistribute it and/or modify
@@ -24,6 +24,8 @@
 #include <stdlib.h>
 #include <unistd.h>
 
+#include "zerosize-ptr.h"
+
 #define ASSERT(expr) \
   do                                                                        \
     {                                                                       \
@@ -78,9 +80,9 @@
     ASSERT (result == input + 11);
   }
 
-  /* Check that length 0 does not dereference NULL.  */
+  /* Check that length 0 does not dereference the pointer.  */
   {
-    const char *result = memmem (NULL, 0, "foo", 3);
+    const char *result = memmem (zerosize_ptr (), 0, "foo", 3);
     ASSERT (result == NULL);
   }
 
--- tests/test-memrchr.c.orig   2009-05-13 02:38:13.000000000 +0200
+++ tests/test-memrchr.c        2009-05-13 01:24:30.000000000 +0200
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2008 Free Software Foundation
+ * Copyright (C) 2008-2009 Free Software Foundation
  * Written by Eric Blake and Bruno Haible
  *
  * This program is free software: you can redistribute it and/or modify
@@ -22,6 +22,8 @@
 #include <stdio.h>
 #include <stdlib.h>
 
+#include "zerosize-ptr.h"
+
 #define ASSERT(expr) \
   do                                                                        \
     {                                                                       \
@@ -41,8 +43,6 @@
 int
 main ()
 {
-  void *nil = NULL; /* Use to avoid gcc attribute((nonnull)) warnings.  */
-
   size_t n = 0x100000;
   char *input = malloc (n);
   ASSERT (input);
@@ -58,7 +58,7 @@
   ASSERT (MEMRCHR (input, 'a', n) == input + n - 1);
 
   ASSERT (MEMRCHR (input, 'a', 0) == NULL);
-  ASSERT (MEMRCHR (nil, 'a', 0) == NULL);
+  ASSERT (MEMRCHR (zerosize_ptr (), 'a', 0) == NULL);
 
   ASSERT (MEMRCHR (input, 'b', n) == input + n - 2);
   ASSERT (MEMRCHR (input, 'c', n) == input + n - 3);
--- modules/memchr-tests.orig   2009-05-13 02:38:13.000000000 +0200
+++ modules/memchr-tests        2009-05-13 01:31:19.000000000 +0200
@@ -1,9 +1,14 @@
 Files:
 tests/test-memchr.c
+tests/zerosize-ptr.h
+m4/mmap-anon.m4
 
 Depends-on:
+getpagesize
 
 configure.ac:
+gl_FUNC_MMAP_ANON
+AC_CHECK_FUNCS_ONCE([mprotect])
 
 Makefile.am:
 TESTS += test-memchr
--- modules/memchr2-tests.orig  2009-05-13 02:38:13.000000000 +0200
+++ modules/memchr2-tests       2009-05-13 01:31:22.000000000 +0200
@@ -1,9 +1,14 @@
 Files:
 tests/test-memchr2.c
+tests/zerosize-ptr.h
+m4/mmap-anon.m4
 
 Depends-on:
+getpagesize
 
 configure.ac:
+gl_FUNC_MMAP_ANON
+AC_CHECK_FUNCS_ONCE([mprotect])
 
 Makefile.am:
 TESTS += test-memchr2
--- modules/memcmp-tests.orig   2009-05-13 02:38:13.000000000 +0200
+++ modules/memcmp-tests        2009-05-13 01:31:32.000000000 +0200
@@ -1,9 +1,14 @@
 Files:
 tests/test-memcmp.c
+tests/zerosize-ptr.h
+m4/mmap-anon.m4
 
 Depends-on:
+getpagesize
 
 configure.ac:
+gl_FUNC_MMAP_ANON
+AC_CHECK_FUNCS_ONCE([mprotect])
 
 Makefile.am:
 TESTS += test-memcmp
--- modules/memmem-tests.orig   2009-05-13 02:38:13.000000000 +0200
+++ modules/memmem-tests        2009-05-13 01:31:29.000000000 +0200
@@ -1,9 +1,14 @@
 Files:
 tests/test-memmem.c
+tests/zerosize-ptr.h
+m4/mmap-anon.m4
 
 Depends-on:
+getpagesize
 
 configure.ac:
+gl_FUNC_MMAP_ANON
+AC_CHECK_FUNCS_ONCE([mprotect])
 AC_CHECK_DECLS_ONCE([alarm])
 
 Makefile.am:
--- modules/memrchr-tests.orig  2009-05-13 02:38:13.000000000 +0200
+++ modules/memrchr-tests       2009-05-13 01:31:26.000000000 +0200
@@ -1,9 +1,14 @@
 Files:
 tests/test-memrchr.c
+tests/zerosize-ptr.h
+m4/mmap-anon.m4
 
 Depends-on:
+getpagesize
 
 configure.ac:
+gl_FUNC_MMAP_ANON
+AC_CHECK_FUNCS_ONCE([mprotect])
 
 Makefile.am:
 TESTS += test-memrchr
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