On 2011-14-03 I wrote in
<http://lists.gnu.org/archive/html/bug-gnulib/2011-03/msg00117.html>:
> 2) The perror replacement uses strerror, thus clobbering the strerror
> buffer.
> 3) On Cygwin, perror clobbers the strerror buffer.
>
> The fix for 2) should be to change lib/perror.c to call strerror_r.
> The fix for 3) should be to change m4/perror.m4 to enable the replacement
> on Cygwin.
Here comes part 2. Eric, I leave part 3 to you.
2011-05-19 Bruno Haible <br...@clisp.org>
perror: Avoid clobbering the strerror buffer when possible.
* lib/strerror-impl.h: New file, extracted from lib/strerror.c.
* lib/strerror.c: Include it.
* modules/strerror (Files): Add lib/strerror-impl.h.
* lib/perror.c: Include <stdlib.h>, intprops.h, verify.h.
(my_strerror): New function, defined through lib/strerror-impl.h.
(perror): Use it instead of strerror.
* modules/perror (Files): Add lib/strerror-impl.h.
(Depends-on): Remove strerror. Add intprops, verify, strerror_r-posix.
============================= lib/strerror-impl.h =============================
/* strerror-impl.h --- Implementation of POSIX compatible strerror() function.
Copyright (C) 2007-2011 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/>. */
#ifdef STATIC
STATIC
#endif
char *
strerror (int n)
{
static char buf[256];
int ret = strerror_r (n, buf, sizeof (buf));
if (ret == 0)
return buf;
if (ret == ERANGE)
/* If this happens, increase the size of buf. */
abort ();
{
static char const fmt[] = "Unknown error (%d)";
verify (sizeof (buf) >= sizeof (fmt) + INT_STRLEN_BOUND (n));
sprintf (buf, fmt, n);
return buf;
}
}
===============================================================================
--- lib/perror.c.orig Thu May 19 21:44:53 2011
+++ lib/perror.c Thu May 19 21:40:43 2011
@@ -21,12 +21,26 @@
#include <stdio.h>
#include <errno.h>
+#include <stdlib.h>
#include <string.h>
+#include "intprops.h"
+#include "verify.h"
+
+/* Use the system functions, not the gnulib overrides in this file. */
+#undef sprintf
+
+/* my_strerror (errnum) is equivalent to strerror (errnum).
+ But it uses its own buffer, not the one from strerror(). */
+#define STATIC static
+#undef strerror
+#define strerror my_strerror
+#include "strerror-impl.h"
+
void
perror (const char *string)
{
- const char *errno_description = strerror (errno);
+ const char *errno_description = my_strerror (errno);
if (string != NULL && *string != '\0')
fprintf (stderr, "%s: %s\n", string, errno_description);
--- lib/strerror.c.orig Thu May 19 21:44:53 2011
+++ lib/strerror.c Thu May 19 21:22:27 2011
@@ -32,26 +32,6 @@
/* Use the system functions, not the gnulib overrides in this file. */
# undef sprintf
-char *
-strerror (int n)
-{
- static char buf[256];
-
- int ret = strerror_r (n, buf, sizeof (buf));
-
- if (ret == 0)
- return buf;
-
- if (ret == ERANGE)
- /* If this happens, increase the size of buf. */
- abort ();
-
- {
- static char const fmt[] = "Unknown error (%d)";
- verify (sizeof (buf) >= sizeof (fmt) + INT_STRLEN_BOUND (n));
- sprintf (buf, fmt, n);
- return buf;
- }
-}
+# include "strerror-impl.h"
#endif
--- modules/perror.orig Thu May 19 21:44:53 2011
+++ modules/perror Thu May 19 21:23:39 2011
@@ -3,12 +3,15 @@
Files:
lib/perror.c
+lib/strerror-impl.h
m4/perror.m4
Depends-on:
stdio
-errno [test $REPLACE_PERROR = 1]
-strerror [test $REPLACE_PERROR = 1]
+errno [test $REPLACE_PERROR = 1]
+intprops [test $REPLACE_PERROR = 1]
+verify [test $REPLACE_PERROR = 1]
+strerror_r-posix [test $REPLACE_PERROR = 1]
configure.ac:
gl_FUNC_PERROR
--- modules/strerror.orig Thu May 19 21:44:53 2011
+++ modules/strerror Thu May 19 21:19:22 2011
@@ -3,6 +3,7 @@
Files:
lib/strerror.c
+lib/strerror-impl.h
m4/strerror.m4
Depends-on:
--
In memoriam Anne Boleyn <http://en.wikipedia.org/wiki/Anne_Boleyn>
