Date: Sat, 1 Jun 2002 14:08:41 -0700 (PDT) From: Archie Cobbs <archie@dellroad.org> To: Bruce Evans <bde@zeta.org.au> Cc: Archie Cobbs <archie@dellroad.org>, Julian Elischer <julian@elischer.org>, Bosko Milekic <bmilekic@unixdaemons.com>, freebsd-net@FreeBSD.ORG Subject: Re: m_split() considered harmful Message-ID: <200206012108.g51L8f608736@arch20m.dellroad.org> In-Reply-To: <20020602004417.H2786-100000@gamplex.bde.org> "from Bruce Evans at Jun 2, 2002 00:51:56 am"
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Bruce Evans writes: > > 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. Yep, you are right about that case... (as usual :-) -Archie __________________________________________________________________________ Archie Cobbs * Packet Design * http://www.packetdesign.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-net" in the body of the message
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