disabling FORTIFY_SOURCE

[Marcus Meissner]

On Sun, Oct 24, 2010 at 09:50:42AM -0600, Vitaliy Margolen wrote:
> On 10/24/2010 12:32 AM, Marcus Meissner wrote:
> >Actually I would like to know if its just more than the dlls/shell32/pidl.c
> >problem...
> If you take a look at winternl.h you'll see number of structures
> there look like:
> typedef struct _foo {
>     ULONG length;
>     WCHAR buffer[1];
> } foo, *pfoo;
> 
> Or just grep for '\[1\]' in include directory. Lots and lots of
> declarations in all different places.

As I already wrote, this works.

Here is a sample code which shows the problem dlls/shell32/pidl.c has:

$ cat xx1.c
	#include <string.h>
	#include <stdlib.h>

	struct foo {
		int x;
		char y[1];
	};
	union bar {
		struct foo fo;
		long y;
		float fl;
	};

	struct berk {
		int t;
		union bar b;
	};

	int
	main(int argc, char **argv) {
		struct berk *x1;
		struct foo  *x2;

		x1 = malloc (sizeof(struct berk) + 5);
		x2 = malloc (sizeof(struct foo)  + 5);
		strcpy(x1->b.fo.y, "hallo");
		strcpy(x2->y, "hallo");
	}

$ gcc -O2 -Wall -D_FORTIFY_SOURCE=2 -g xx1.c -o xx1
	xx1.c: In function ‘main’:
	xx1.c:28:1: warning: control reaches end of non-void function
	In file included from /usr/include/string.h:640:0,
			 from xx1.c:1:
	In function ‘strcpy’,
	    inlined from ‘main’ at xx1.c:26:8:
	/usr/include/bits/string3.h:107:3: warning: call to __builtin___strcpy_chk will always overflow destination buffer


Only the "strcpy(x1->b.fo.y, "hallo");" with the nested struct is warned
about, while the second strcpy works fine.

It is just nested structs it does not like at this time.

Ciao, Marcus