Date: Thu, 5 May 2005 02:55:10 +0000 From: Alexander Kabaev <kan@freebsd.org> To: Jeff Roberson <jroberson@chesapeake.net> Cc: arch@freebsd.org Subject: Re: printflike vs kprintflike Message-ID: <20050505025509.GA3120@freefall.freebsd.org> In-Reply-To: <20050504180112.M18611@mail.chesapeake.net> References: <20050504180112.M18611@mail.chesapeake.net>
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On Wed, May 04, 2005 at 06:16:06PM -0400, Jeff Roberson wrote:
> I have a patch from Neal Fachan of isilon that implements a new gcc
> attribute 'kprintflike' that is used in place of 'printflike' in the
> kernel. This is done to stop us from leaking kernel printf formats into
> userspace. Apparently -fformat-extensions is broken in gcc3. This also
> stops our formats from leaking into any other custom formats defined in
> gcc.
>
I would like to avoid introduction of a new printf attribute if possible.
Does fixed -fformat-extensions suffice your needs? If so, can you try the
patch below instead?
Index: c-common.h
===================================================================
RCS file: /home/ncvs/src/contrib/gcc/c-common.h,v
retrieving revision 1.7
diff -u -r1.7 c-common.h
--- c-common.h 28 Jul 2004 03:46:02 -0000 1.7
+++ c-common.h 5 May 2005 02:45:10 -0000
@@ -840,6 +840,9 @@
/* Nonzero means the expression being parsed will never be evaluated.
This is a count, since unevaluated expressions can nest. */
+/* Nonzero allows FreeBSD kenrel-specific printf formats. */
+extern int flag_format_extensions;
+
extern int skip_evaluation;
/* C types are partitioned into three subsets: object, function, and
Index: c-format.c
===================================================================
RCS file: /home/ncvs/src/contrib/gcc/c-format.c,v
retrieving revision 1.9
diff -u -r1.9 c-format.c
--- c-format.c 28 Jul 2004 03:57:21 -0000 1.9
+++ c-format.c 5 May 2005 02:33:31 -0000
@@ -257,7 +257,8 @@
STD_C94,
STD_C9L, /* C99, but treat as C89 if -Wno-long-long. */
STD_C99,
- STD_EXT
+ STD_EXT,
+ STD_BSD
};
/* The C standard version C++ is treated as equivalent to
@@ -785,9 +786,9 @@
("%6D", ptr, ":") -> XX:XX:XX:XX:XX:XX
("%*D", len, ptr, " ") -> XX XX XX XX ...
*/
- { "D", 1, STD_EXT, { T89_C, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "cR" },
- { "b", 1, STD_EXT, { T89_C, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "" },
- { "ry", 0, STD_EXT, { T89_I, BADLEN, BADLEN, T89_L, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp0 +#", "i" },
+ { "D", 1, STD_BSD, { T89_C, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "cR" },
+ { "b", 1, STD_BSD, { T89_C, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp", "" },
+ { "ry", 0, STD_BSD, { T89_I, BADLEN, BADLEN, T89_L, BADLEN, BADLEN, BADLEN, BADLEN, BADLEN }, "-wp0 +#", "i" },
{ NULL, 0, 0, NOLENGTHS, NULL, NULL }
};
@@ -2091,7 +2092,8 @@
format_chars++;
fci = fki->conversion_specs;
while (fci->format_chars != 0
- && strchr (fci->format_chars, format_char) == 0)
+ && (strchr (fci->format_chars, format_char) == 0 ||
+ (!flag_format_extensions && fci->std == STD_BSD)))
++fci;
if (fci->format_chars == 0)
{
Index: c-opts.c
===================================================================
RCS file: /home/ncvs/src/contrib/gcc/c-opts.c,v
retrieving revision 1.2
diff -u -r1.2 c-opts.c
--- c-opts.c 29 Jul 2004 02:04:58 -0000 1.2
+++ c-opts.c 5 May 2005 02:41:26 -0000
@@ -1047,6 +1047,7 @@
break;
case OPT_fformat_extensions:
+ flag_format_extensions = value;
break;
}
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