Date: Tue, 10 Aug 2010 14:19:58 -0600 (MDT) From: "M. Warner Losh" <imp@bsdimp.com> To: olli@fromme.com Cc: src-committers@FreeBSD.org, jilles@stack.nl, svn-src-all@FreeBSD.org, olli@FreeBSD.org, svn-src-head@FreeBSD.org, des@des.no Subject: Re: svn commit: r211023 - head/usr.sbin/syslogd Message-ID: <20100810.141958.923962171922746057.imp@bsdimp.com> In-Reply-To: <201008101956.o7AJu5ms044774@haluter.fromme.com> References: <20100810.120103.69891821625677670.imp@bsdimp.com> <201008101956.o7AJu5ms044774@haluter.fromme.com>
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In message: <201008101956.o7AJu5ms044774@haluter.fromme.com>
Oliver Fromme <olli@fromme.com> writes:
:
: M. Warner Losh wrote:
: > /*
: > * Macros to cast a struct sockaddr, or parts thereof. struct
: > * sockaddr's alginment is loose to later be cast to a sockaddr_in or
: > * sockaddr_in6. On architectures with strict alignment requirements,
: > * this leads to compiler warnings because the compiler doesn't know
: > * the ABI guarantees proper alignment.
: > */
: >
: > But this leads me to think that the right fix might be:
: >
: > /*
: > * Structure used by kernel to store most
: > * addresses.
: > */
: > struct sockaddr {
: > unsigned char sa_len; /* total length */
: > sa_family_t sa_family; /* address family */
: > char sa_data[14]; /* actually longer; address value */
: > } __aligned(4);
: >
: > since that's what the ABI defines....
:
: Yes, that would solve most of the problems, at least the ones
: related to struct sockaddr.
:
: Can we make that change to struct sockaddr, or does it cause
: unwanted side-effects?
:
: I could do a full "make universe" to test it, but it would
: probably take two days on my 9-current machine.
Just do it on MIPS.
You'll find that a number of structures are potentially already
allocated with less than required alignment. There's about a dozen
places in the tree that would start to fail if we did this, or the
stronger form of __aligned(8). We could add that to the other
structures, but then we're breaking ABI rules, I think.
Warner
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