October 2007 - Darwin-kernel

Re: Kernel authorization (Kauth) from user space
by Liviu Andron 12 Oct '07

12 Oct '07

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=beta; h=domainkey-signature:received:received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; bh=b772VejjAkPwEaksgO7lil+53fP9UnAkDjzBznKbBJ4=; b=Hpcd5GEZUS8bFwyhpO69fuQGMdL0e8ri3V3+xw24/v5+izuEUPkxbAOUj4Xr4vAmtKUC96vjAuvLsNVTXVuHZqiy0KsCSKbLSUb6yVCgYjqwUMyDJ6bk/HIT1IT02YnQIdNBQK79QPwhUVoZ2W2Nc2UMnrDSXR8CMDa1XPaDomA= Domainkey-signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=ets7RizYCoMnxyJUFth4k6SHa6oQluvliYuM3PBxuhXwlI1EtzoI607O5p3QeFFfxjcGwOZwlNTYB9tp73Uhh0Rf+WlbkwXtDAgGFoM/8zxMHo3pndzreau51h4CRT10gl/XmYsJRN+LYa/KK6DHOFwPk2GY/MDoZMYnVGl4XXU= On 10/11/07, Jernej Azarija <Jernej.Azarija(a)hermes-softlab.com> wrote: > > > 1) The recommended way from the technical documentation is to read/write > in > >kernel, but all the mailing lists discussions say to do it in user space. > In userspace? It depends on what you need to accomplish. I need to read and/or write from/to files in both fileop scope and vnode scope listeners. > > > 2) Assuming that I send the path from kernel to the user space daemon > >(returned by vn_getpath from the vnode parameter) , I have the following > >issues: > > Actually, one of the kauth hook function arguments is the relevant path > name - > you just have to cast it to (char *). > > > > - for files with paths longer than MATXPAHTLEN (1024) , which can > be > >created with Finder: > > - vn_getpath returns error 28 (KERN_INVALID_POLICY) > > - the callback for OPEN/CLOSE actions is called with empty > >path (arg1) or it's not called at all > > Use the supplied path as said. You'll only have to play about transfering > the path to userspace. In the vnode listener you have no path. Please read all the message. > > > 4) Another possible solution seems to be using VNOP_READ/VNOP_WRITE in > >kernel space and transfer data to daemon > > If you only need to hook open/close, use KAUTH_SCOPE_FILEOP. It's not > reasonable to hook VNODE operations - at last from the performance view. I don't want to hook the operations, I want to use them for read or write from/to files. Opening a path in user mode is ok if the paths can be always retrieved (vn_getpath or listener argument), are limited and the userland's open doesn't have problems with exclusive accesses. If not then a different approach is needed, the points 3) and 4) from the initial post are possible solutions. Or maybe there's another one !? Thanks, Liviu _______________________________________________ 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 authorization (Kauth) from user space
by Jernej Azarija 11 Oct '07

11 Oct '07

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Kernel authorization (Kauth) from user space
by Liviu Andron 11 Oct '07

11 Oct '07

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How to proxy a non blocking connect with a socket filter?
by Karl Pickett 09 Oct '07

09 Oct '07

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Re: Loading Kext at Boot Time
by Dean Reece 05 Oct '07

05 Oct '07

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Loading Kext at Boot Time
by JanakiRam 05 Oct '07

05 Oct '07

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[darwin-kernel] IODMACommands, prepare, and writeBytes
by Alexander von Below 05 Oct '07

05 Oct '07

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hello List, So far, so good. Thanks for any hints and pointers Alex I dislike crossposting, like most people, but as ata-scsi-dev seems to be rather deserted, forgive me if I repost this on darwin-kernel We are writing a SCSI HBA, which wants to use DMA. However, some things -- such as inquiries -- are caught in the driver area. This information is then to be copied from a local buffer to the IOMemoryDescriptor of the SCSIParallelTaskIdentifier (obtained from GetDataBuffer) using writeBytes. Now, other commands (notably read and write), are to get their data via DMA, and here is the probelm: Documentation tells us we can not prepare anything in a gated context. Other documentation tells us to use a commandGate for synchronization. This means, we have to prepare outside of the gated context. If we prepare the memory descriptor, writeBytes reports success, but no bytes are delivered to a _ user space process _ sending an inquiry command via the SCSI Task User Client (the kernel is apparently able to query our drive still) If we don't prepare the memory, generating segments fails with 0xe00002d8, "not ready". We would not like having to make a distinction prior to the gated context, if we are or are not going to use DMA. How can we handle this issue? P.S. A DTS Incident for this has been filed, 34298181, but I wanted to see if the all-knowing list has some insight, too _______________________________________________ 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: ctl_enqueuedata() woes - FIXED
by Adi Masputra 04 Oct '07

04 Oct '07

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Yes, if this is a SOCK_DGRAM socket, specifying 0 will cause the current data to be appended to the previous one in the socket without a message boundary. A read done on the socket will either truncate or discard data enqueued to it after the 1st one. That's what CTL_DATA_EOR is for, as you've already discovered. Adi On Oct 4, 2007, at 8:16 AM, Karl Pickett wrote: On 10/3/07, Adi Masputra < adi(a)apple.com> wrote: How are you calling ctl_enqueuedata() -- i.e. what are its parameters? Adi I tested it, that was indeed the problem. Thanks! _______________________________________________ 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 I was calling it with 0 for flags, as per the example code. Gee. I was wondering what CTL_DATA_EOR was for since the example didn't use it. It looks like my code and the example code would be better off using CTL_DATA_EOR :) -- Karl Pickett "They that can give up essential liberty to obtain a little temporary safety deserve neither liberty nor safety." -- Benjamin Franklin "Eternal vigilance is the price of liberty." -- Wendell Phillips "One man with courage makes a majority." -- Andrew Jackson, 1832 smime.p7s

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Re: ctl_enqueuedata() woes - FIXED
by Karl Pickett 04 Oct '07

04 Oct '07

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Re: ctl_enqueuedata() woes
by Stephane Sudre 04 Oct '07

04 Oct '07

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On 3 oct. 07, at 21:12, Brian Bergstrand wrote: On Oct 3, 2007, at 7:58 PM, Josh Graessley wrote: On Oct 3, 2007, at 9:55 AM, Brian Bergstrand wrote: On Oct 3, 2007, at 7:26 PM, Karl Pickett wrote: _______________________________________________ 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 have modified the tcplognke example and it was pleasant sailing until now. I am sending packets to userspace that are about 2020 bytes long. Userspace reads each packet and responds with a setsockopt() call with a 2k structure. When a burst of packets gets sent, some packets will fail to be received by user space but no error was indicated from ctl_enqueuedata() Calling ctl_getenqueuespace(), the packets end up disappearing when ever the queuespace is not the maximum. Bumping up the socket recvbuf from 8k to 60k did not help one bit! ut otherwise the packets would just disappear when ever the enqueuespace was not at max. This is how control sockets work. Here's a way to get around the problem (if you can gracefully sleep that is): int retry = 3; retry_data: size_t recvsz = 0; if (0 == ctl_getenqueuespace(ctl_ref, ctlunit, &recvsz) && recvsz < datasize && retry > 0) { // msg q is full // Sleep one quantum giving the client a chance to wake struct timespec ts = {0, 10000000}; (void)msleep(NULL, NULL, PSOCK, __FUNCTION__, &ts); retry--; goto retry_data; } err = ctl_enqueuedata(...); Please don't do this. If you're running on the input thread you're going to hurt network performance. -josh Well, for me, this code is in a separate thread not involved in the network stack. But if we aren't supposed to do this in a network callback (which again, I'm not doing) what are we supposed to do? As Karl pointed out, ctl_enquedata doesn't handle this case itself, so we have to. IIRC, the tcpkernellogsomething example queues the data until it can send it later. This can be a solution if the data to queue is not too big (size or instances) and you don't need to receive the data as soon as it's made available (and you can be sure that there will be a call to ctl_enqueuedata after you've queued the data. This email sent to site_archiver(a)lists.apple.com

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