October 2006 - Darwin-kernel

ctl_getenqueuespace question
by Bhavesh Davda 02 Oct '06

02 Oct '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Domainkey-signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition; b=sJeiHFgrGdn4DUsc9A51dkviqjUP8kfMxFln+GH16GpfaRboQmUdWg7SpZsCq9spgG9ybeP9IqHbupr28nz5w2G7m6qsO1LPk97SolCrxhlpsDCqnKznfg8AQlcIWkUP1yI13fnCwFN6mIOoCwaQCT/o8ZZGIyUKmX5PZ+3fukQ= In my NKE, I do: size_t queueRoom, mbufLen; ... ctl_getenqueuespace(ctlRef, unit, &queueRoom); ... mbufLen = mbuf_pkthdr_len(m); ... if (queueRoom < mbufLen) { // drop packet } else { if ((err = ctl_enqueuembuf(ctlRef, unit, m, CTL_DATA_EOR)) != 0) { // error log; drop packet } I'm seeing that ctl_getenqueuespace() sometimes returns queueRoom == 0xfffffe00, which interpreted as a size_t is 4294966784. When mbufLen == 1514, this is less than 4294966784, so I attempt to call ctl_enqueuembuf(...). But then ctl_enqueuembuf() returns ENOBUFS. Looking in the xnu-792.10.96/bsd/kern/kernl_control.c code, I see the check: ... if (sbspace(&so->so_rcv) < m->m_pkthdr.len) { error = ENOBUFS; goto bye; } ... This is pretty much the same check as my NKE code above, with the one notable difference of the types of queueRoom/mbufLen versus the value returned by sbspace(). Could this be a type conversion bug? If so, are there any workarounds? Also, I spend a couple of hours trying to figure out what sbspace() really does, and gave up after getting more confused then when I started looking at it :) Can someone explain the intent of sbspace() in English? Thanks -- Bhavesh P. Davda _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: Kernel Debug Kits for 10.4.8
by Garth Cummings 02 Oct '06

02 Oct '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Kernel Debug Kits for 10.4.8
by Michael Tuexen 02 Oct '06

02 Oct '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dear all, will there be any Kernel Debug Kits available for 10.4.8? Best regards Michael _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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Re: kev_msg_post size limitation
by Michael Smith 02 Oct '06

02 Oct '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On Oct 2, 2006, at 1:38 AM, Jérome Foucher wrote: = Mike _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I'm posting events from my KEXT to a user-land process using kev_msg_post() The doc states that this function returns EMSGSIZE if the message is too large. This is quite an issue for me, and the doc doesn't say anything about the max size. So can anyone tell me : - what is the exact maximum size of the message structure ? - if the max size depends on the kev_class or kev_subclass parameters of the message ? - if there's another function to use instead of kev_msg_post() to post larger messages to user-land (I might have to post messages as large as 1KB), or do I have to split my message into several pieces (in that case, can I be sure my user-land process will receive the messages in the exact post order ?) ? Don't post large messages to user space. Doing so assumes that the kernel will queue these messages for you, and that it will do so in a fashion that suits your application. It also means that the message will have to be copied, and the kernel is on the hook to hold onto that message effectively forever. Instead, post a message to your application telling it to come fetch this large message, or consider using an another method of communication that has a buffering model that suits your application (e.g. kernel control socket, I/O Kit userclient methods). This email sent to site_archiver(a)lists.apple.com

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kev_msg_post size limitation
by Jérome Foucher 02 Oct '06

02 Oct '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hi list, Thanks Jérome _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… I'm posting events from my KEXT to a user-land process using kev_msg_post() The doc states that this function returns EMSGSIZE if the message is too large. This is quite an issue for me, and the doc doesn't say anything about the max size. So can anyone tell me : - what is the exact maximum size of the message structure ? - if the max size depends on the kev_class or kev_subclass parameters of the message ? - if there's another function to use instead of kev_msg_post() to post larger messages to user-land (I might have to post messages as large as 1KB), or do I have to split my message into several pieces (in that case, can I be sure my user-land process will receive the messages in the exact post order ?) ? This email sent to site_archiver(a)lists.apple.com

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Can't compile cp
by Jeffrey Ellis 01 Oct '06

01 Oct '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: Acbk/XLEsUyAcVDwEdu6LwANk0QgEg== Thread-topic: Can't compile cp User-agent: Microsoft-Entourage/11.2.5.060620 I copied the code from cp into a new file but it won't compile because Xcode can't find the file copyfile.h. For starters, #ifdef __APPLE__ #include <copyfile.h> #endif and there are several places in the code, also bracketed by #ifdef __APPLE__, which calls a copyfile() function. Skimming through the code quickly, and by implication of its name, it seems that this function is doing the "actual work" of copying, but that doesn't quite make sense because these invocations should be followed by and #elsif, and then some other routines to use if __APPLE__ is not defined. I mean, if you compiled this code without __APPLE__ defined, whatever copyfile does (copying a file, it looks like) would not get done. Anyhow, I cannot find copyfile.h anywhere on my hard drive nor in the ADC (Apple Developer Connection) website. Does anyone know where to get it? Thanks again :) All My Best, Jeffrey _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel(a)lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.… This email sent to site_archiver(a)lists.apple.com

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