Date: Sun, 2 Jun 2002 00:51:56 +1000 (EST) From: Bruce Evans <bde@zeta.org.au> To: Archie Cobbs <archie@dellroad.org> Cc: Julian Elischer <julian@elischer.org>, Bosko Milekic <bmilekic@unixdaemons.com>, <freebsd-net@FreeBSD.ORG> Subject: Re: m_split() considered harmful Message-ID: <20020602004417.H2786-100000@gamplex.bde.org> In-Reply-To: <200205312025.g4VKP9t02205@arch20m.dellroad.org>
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On Fri, 31 May 2002, Archie Cobbs wrote: > That is, what we really need is a more general audit for code that > writes into mbufs that might be read-only -- and, as one special case > of tha, code that calls M_TRAILINGSPACE()/M_LEADINGSPACE() before writing > into an mbuf. > > FYI, any easy way to do this would be to add const'ness to mtod(): > > #define mtod(m, t) ((const t)((m)->m_data)) > > and then look for GCC warnings. Any takers?? :-) This assumes that t is literally a pointer. When t is caddr_t, `const t' is a const variable which (if caddr_t is `char *') is a pointer to non-const storage, but you want a non-const pointer to const storage. Bruce To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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