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Re: [PATCH] Lacking strtok_r



On Fri, Mar 28, 2008 at 08:33:00AM -0700, Dan Fandrich wrote:
> On Fri, Mar 28, 2008 at 12:36:58PM +0100, Alain Bench wrote:
> >     ...due to recursive calls to strtok(). We'd need a replacement
> > strtok_r() for systems where it lacks.
> 
> Hmmm, I didn't notice the recursion--that explains the change to
> strtok_r.  I'll see what I can do about that.

Attached is a patch that replaces strtok_r when it's not available. It
comes from glibc 2.6.1 (like the strsep replacement) and uses the same
autoconf hooks.

It would be a good idea now to replace all strtok calls with strtok_r so
the same types of bugs that occurred in the past don't accidentally
recur as changes are made in the future.

>>> Dan
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--- configure.ac.orig   Fri Mar 28 13:20:24 2008
+++ configure.ac        Fri Mar 28 13:18:29 2008
@@ -335,7 +335,7 @@
 
 AC_CHECK_FUNCS(fgetpos memmove setegid srand48 strerror)
 
-AC_REPLACE_FUNCS([setenv strcasecmp strdup strsep])
+AC_REPLACE_FUNCS([setenv strcasecmp strdup strsep strtok_r])
 
 AC_CHECK_FUNC(getopt)
 if test $ac_cv_func_getopt = yes; then
--- /dev/null   Tue Apr 25 01:53:54 1995
+++ strtok_r.c  Fri Mar 28 13:19:37 2008
@@ -0,0 +1,63 @@
+/* Reentrant string tokenizer.  Generic version.
+   Copyright (C) 1991,1996-1999,2001,2004 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, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#include <string.h>
+
+/* Taken from glibc 2.6.1 */
+
+/* Parse S into tokens separated by characters in DELIM.
+   If S is NULL, the saved pointer in SAVE_PTR is used as
+   the next starting point.  For example:
+       char s[] = "-abc-=-def";
+       char *sp;
+       x = strtok_r(s, "-", &sp);      // x = "abc", sp = "=-def"
+       x = strtok_r(NULL, "-=", &sp);  // x = "def", sp = NULL
+       x = strtok_r(NULL, "=", &sp);   // x = NULL
+               // s = "abc\0-def\0"
+*/
+char *
+strtok_r (char *s, const char *delim, char **save_ptr)
+{
+  char *token;
+
+  if (s == NULL)
+    s = *save_ptr;
+
+  /* Scan leading delimiters.  */
+  s += strspn (s, delim);
+  if (*s == '\0')
+    {
+      *save_ptr = s;
+      return NULL;
+    }
+
+  /* Find the end of the token.  */
+  token = s;
+  s = strpbrk (token, delim);
+  if (s == NULL)
+    /* This token finishes the string.  */
+    *save_ptr = strchr (token, '\0');
+  else
+    {
+      /* Terminate the token and make *SAVE_PTR point past it.  */
+      *s = '\0';
+      *save_ptr = s + 1;
+    }
+  return token;
+}