Subject: Re: PATH_MAX and FILENAME_MAX
From: "J. Johnston" <[email-masked]>
To: Earnie Boyd <[email-masked]>, [email-masked]
Cc: Andrej Borsenkow <[email-masked]>, [email-masked]
Date: Fri, 26 Jan 2001 17:31:52 -0500

Earnie Boyd wrote:
> 
> Andrej Borsenkow wrote:
> >
> > Doing something different, this caught my eyes:
> >
> > $ grep PATH_MAX /usr/include/*.h
> > /usr/include/limits.h:#define PATH_MAX (260 - 1 /*NUL*/)
> > /usr/include/limits.h:#define _POSIX_PATH_MAX           255
> > /usr/include/stdio.h:#define    FILENAME_MAX    1024    /* must be <= PATH_MAX
> > <sys/syslimits.h> */
> > /usr/include/stdio.h:#define    L_tmpnam        1024    /* XXX must be ==
> > PATH_MAX */
> >
> > So are comments misleading or FILENAME_MAX (and L_tmpnam) should be changed?
> >
> 
> The comments are correct.  This is a newlib issue.  I've CC'ed the
> newlib list in my response.
> 

Actually, the comments are not quite correct.  Based on POSIX, the value FOPEN_MAX should 
be tied to STREAM_MAX, not OPEN_MAX.  The value of L_tmpnam should be <= PATH_MAX,
like FILENAME_MAX.

As a solution, I have made a patch that adds the ability for config.h
or the compiler to override the default values for FOPEN_MAX, FILENAME_MAX, and L_tmpnam.
I have altered config.h for RTEMS and Cygwin to set the value of __FILENAME_MAX__
appropriately.

Any comments/objections from Cygwin or RTEMS?

-- Jeff J.

? max.patch
? math.h.new
? stdio.patch
Index: stdio.h
===================================================================
RCS file: /cvs/src/src/newlib/libc/include/stdio.h,v
retrieving revision 1.4
diff -u -r1.4 stdio.h
--- stdio.h	2000/05/30 17:18:05	1.4
+++ stdio.h	2001/01/26 22:16:56
@@ -90,9 +90,27 @@
 #define	BUFSIZ	1024
 #define	EOF	(-1)
 
-#define	FOPEN_MAX	20	/* must be <= OPEN_MAX <sys/syslimits.h> */
-#define	FILENAME_MAX	1024	/* must be <= PATH_MAX <sys/syslimits.h> */
-#define	L_tmpnam	1024	/* XXX must be == PATH_MAX */
+/* FOPEN_MAX should equal STREAM_MAX */
+#ifdef __FOPEN_MAX__
+#define FOPEN_MAX	__FOPEN_MAX__
+#else
+#define	FOPEN_MAX	20
+#endif
+
+/* FILENAME_MAX must be <= PATH_MAX */
+#ifdef __FILENAME_MAX__
+#define FILENAME_MAX    __FILENAME_MAX__
+#else
+#define	FILENAME_MAX	1024
+#endif
+
+/* L_tmpnam must be <= PATH_MAX */
+#ifdef __L_tmpnam__
+#define L_tmpnam	__L_tmpnam__
+#else
+#define	L_tmpnam	FILENAME_MAX
+#endif
+
 #ifndef __STRICT_ANSI__
 #define P_tmpdir        "/tmp"
 #endif
Index: sys/config.h
===================================================================
RCS file: /cvs/src/src/newlib/libc/include/sys/config.h,v
retrieving revision 1.4
diff -u -r1.4 config.h
--- config.h	2000/08/01 20:51:51	1.4
+++ config.h	2001/01/26 22:16:56
@@ -127,11 +127,16 @@

 #if defined(__CYGWIN32__) || defined(__CYGWIN__)
+#define __FILENAME_MAX__ (260 - 1 /* NUL */)
 #if defined(__INSIDE_CYGWIN__) || defined(_COMPILING_NEWLIB)
 #define __IMPORT
 #else
 #define __IMPORT __declspec(dllimport)
 #endif
+#endif
+
+#if defined(__rtems__)
+#define __FILENAME_MAX__ 255
 #endif
 
 #ifndef __IMPORT

--
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