From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <5.1.0.14.2.20030425153625.081db0f0@unixmail.qualcomm.com> To: David Woodhouse From: Max Krasnyansky Subject: Re: [Bluez-devel] [PATCH] Fix abuse of kernel headers. Cc: bluez-devel@lists.sourceforge.net In-Reply-To: <1051305362.13999.115.camel@imladris.demon.co.uk> References: <5.1.0.14.2.20030425104103.1040bb30@unixmail.qualcomm.com> <5.1.0.14.2.20030425104103.1040bb30@unixmail.qualcomm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: bluez-devel-admin@lists.sourceforge.net Errors-To: bluez-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Id: List-Unsubscribe: , List-Archive: Date: Fri, 25 Apr 2003 15:49:26 -0700 At 02:16 PM 4/25/2003, David Woodhouse wrote: >On Fri, 2003-04-25 at 18:43, Max Krasnyansky wrote: >> At 06:25 AM 4/25/2003, David Woodhouse wrote: >> >Thou Shalt Not Use Private Kernel Headers In Userspace. >> Yes. But asm/unaligned.h is the integral part of the glibc headers. > >Take a look at the PPC version. /* * The PowerPC can do unaligned accesses itself in big endian mode. * * The strange macros are there to make sure these can't * be misused in a way that makes them not work on other * architectures where unaligned accesses aren't as simple. */ #define get_unaligned(ptr) (*(ptr)) #define put_unaligned(val, ptr) ((void)( *(ptr) = (val) )) Looks ok to me ;-). But I do remember some problem on some arch. Which was the reason why I implemented sdp_get_unaligned() instead of using >The rule is that you're not permitted to use _anything_ in asm/ or >linux/ directly from userspace. We know people do, but they shouldn't, >and if it breaks they get to keep both pieces. >> >- return ntohs(get_unaligned(u16_ptr)); >> >+ return (u8_ptr[0] << 8) | u8_ptr[1]; >> I'd rather see reimplementation of get_unaligned() in hcidump headers >> than this. We have sdp_get/put_unaligned() btw. > >I looked at that but AFAIK the C standard doesn't actually guarantee the >packed structure method will work I don't think packet structures are in the standard. But compiler has to guarantee that. Otherwise we'd have big problems (all hci structures are packed). >and since we were always byteswapping No we don't. ntohs does nothing on big endian machines. Max ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Bluez-devel mailing list Bluez-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/bluez-devel