[DTrace-devel] [PATCH 4/7] Increase the maximum size of strstab

[Eugene Loh]

I do not understand this.  If the limit is SSIZE_MAX, then there is no 
point in having a max (or a max check) at all.  The test (soff > 
DIF_STROFF_MAX) can never fail.  So is the point to use a higher limit, 
or to remove the limit entirely?

On 12/6/22 16:50, Kris Van Hees via DTrace-devel wrote:
> The strtab size was limited in the legacy version to 0x7fff.  This
> was generally sufficient because of how the strtab was implemented.
> Now that all strings used in a probe program are stored in a single
> strtab (incl. probe description names), a higher limit is needed.
>
> All string offsets (and strtab size calculations) are using ssize_t,
> so we use SSIZE_MAX as the upper limit.
>
> Signed-off-by: Kris Van Hees <kris.van.hees at oracle.com>
> ---
>   include/dtrace/dif_defines.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/dtrace/dif_defines.h b/include/dtrace/dif_defines.h
> index 43824646..d88b3b2e 100644
> --- a/include/dtrace/dif_defines.h
> +++ b/include/dtrace/dif_defines.h
> @@ -113,7 +113,7 @@
>   #endif
>   
>   #define	DIF_INTOFF_MAX		0xffff	/* highest integer table offset */
> -#define	DIF_STROFF_MAX		0x7fff	/* highest string table offset */
> +#define	DIF_STROFF_MAX		SSIZE_MAX /* highest string table offset */
>   #define	DIF_REGISTER_MAX	0xff	/* highest register number */
>   #define	DIF_VARIABLE_MAX	0xffff	/* highest variable identifier */
>   #define	DIF_SUBROUTINE_MAX	0xffff	/* highest subroutine code */