September 2006 - Darwin-kernel

Re: How to retrieve buffer from struct uio ?
by sanjay yaragatti 12 Sep '06

12 Sep '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=s1024; d=yahoo.co.in; h=Message-ID:Received:Date:From:Subject:To:Cc:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=6cji+MKpSx645otmHwUw86lF7IhDsmiI5PgqwPKaZVyVucsiiyiG8W1felm9BrDTNSKfnzZFzqJrmsiZVhNK9ext7fvpxQoR9+wbaT1ETMhzRCx6a3KOnBLnlBqM/BXQHjr6HhbMjQdD7pWm9r/WsXGCgM8MDICmQbCrbwh+Ihw= ; Thanks Terry. Now i am able to retrieve the buffer from the struture uio.Thanks a lot for providing pointers :-) Regards, Sanjay --- Terry Lambert <tlambert(a)apple.com> wrote: > On Sep 12, 2006, at 2:13 AM, sanjay yaragatti wrote: > > > > Hi all, > > I am writing a kernel driver.I have > regestered it > > as character device. I am unable to implement the > > device write method (dev_write( dev_t device, > struct > > uio *uio, int ioflag)) since I don't know how to > > retrieve the buffer from struct uio. > > > > However on trying to dereference uio as > > uio->uio_iov->iov_base gave a compilation error. > > > > Is there a KPI to retrieve the buffer sent from > user > > space? > > You may want to read /usr/include/sys/uio.h... > > > /* > * uio_curriovbase - return the base address of the > current iovec > associated > * with the given uio_t. May return 0. > */ > user_addr_t uio_curriovbase( uio_t a_uio ); > > > You can also look at the kernel sources; in this > case, the function is > implemented in: > > > <http://www.opensource.apple.com/darwinsource/10.4.7.ppc/xnu-792.6.76/bsd/ke… > > > > > -- Terry > __________________________________________________________ Yahoo! India Answers: Share what you know. Learn something new http://in.answers.yahoo.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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Re: How to retrieve buffer from struct uio ?
by Terry Lambert 12 Sep '06

12 Sep '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hi all, I am writing a kernel driver.I have regestered it as character device. I am unable to implement the device write method (dev_write( dev_t device, struct uio *uio, int ioflag)) since I don't know how to retrieve the buffer from struct uio. However on trying to dereference uio as uio->uio_iov->iov_base gave a compilation error. Is there a KPI to retrieve the buffer sent from user space? You may want to read /usr/include/sys/uio.h... -- Terry _______________________________________________ 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.… On Sep 12, 2006, at 2:13 AM, sanjay yaragatti wrote: /* * uio_curriovbase - return the base address of the current iovec associated * with the given uio_t. May return 0. */ user_addr_t uio_curriovbase( uio_t a_uio ); You can also look at the kernel sources; in this case, the function is implemented in: <http://www.opensource.apple.com/darwinsource/10.4.7.ppc/xnu-792.6.76/bsd/ke… > This email sent to site_archiver(a)lists.apple.com

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How to retrieve buffer from struct uio ?
by sanjay yaragatti 12 Sep '06

12 Sep '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=s1024; d=yahoo.co.in; h=Message-ID:Received:Date:From:Subject:To:MIME-Version:Content-Type:Content-Transfer-Encoding; b=uKMHIx+or1qYsaL5xK1vBHwC7QWqQEJepK5TEZse7FtkcLjijjCr+7uKxKmBFui4c5lCu4MoPYbTz0g7S9z5Itj3rF4VC0758sC+vgrDOyM8SxhuOwyMzretzTpjYJ2ev+NvXqfmYCw5LvOqfSYaiEBKD1ohHYB3GBXF0Uz6e4o= ; Hi all, I am writing a kernel driver.I have regestered it as character device. I am unable to implement the device write method (dev_write( dev_t device, struct uio *uio, int ioflag)) since I don't know how to retrieve the buffer from struct uio. However on trying to dereference uio as uio->uio_iov->iov_base gave a compilation error. Is there a KPI to retrieve the buffer sent from user space? Thanks, Sanjay __________________________________________________________ Yahoo! India Answers: Share what you know. Learn something new http://in.answers.yahoo.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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VFS write operations
by Michael Welch 12 Sep '06

12 Sep '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: AcbWCQ7yIQuJPmVgTJexA8FkeveCCQ== Thread-topic: VFS write operations Hello - I'm writing a VFS (on 10.4) which provides a view of files available in some repository somewhere but may not actually reside on the local disk, fetching as necessary (think webdavfs). When I see read/write requests to one of my vnodes, I pass the operation along with VNOP_READ/VNOP_WRITE, substituting my vnode with one for a cache file on disk. I've hit a wall when it comes to adding write support. >From the terminal, I can read (e.g. $cat filename), write $echo "foo" > filename), and append ($echo "foo" >> filename). All seems well. Then I try to write from a simple app like TextEdit... here's where the fun begins. I open a file in TextEdit (it can read just fine), make some changes, and hit save. From what I can decipher, TextEdit performs the following steps (with the corresponding VNOP's going through my VFS): 1) Open the existing file, read a whole slew of attributes (permissions, file size, timestamps, etc.), and then close the file. 2) Repeat (1) for the parent dir, it's parent, etc. up to the root of the file system. 3) Create a temporary file, open it, and write the data. 4) Read some attributes on the temp file (only uid, gid, flags, fileid, and fsid) and close it. 5) Delete the temp file. 6) Report that the file could not be saved (duh - you just deleted it!). My best (only) guess is that it's unhappy with the attributes it sees - but what I return in those attributes are the same values specified during file creation time (except size, which is updated at write time). Stepping through I've verified that the temp file is created in the same directory as my cache file and the data is in fact written to it after step 3. The attributes look right. So writing a file from TextEdit fails. However - if the file size is zero, the save succeeds (that is, if the new size is zero, regardless of what the old size was). Instead of (4) and (5), it does what you'd pretty much expect - delete the original file and rename the temp file back into place. I see similar behavior in other apps - only the command line stuff seems to work correctly. I've been staring at this for several days, and I can't seem to find where this could be going wrong. There are probably a lot more details necessary to solve the problem, but before I go any further, does anybody out there have some ideas? What additional info do you need to proceed? Thanks, - 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.… This email sent to site_archiver(a)lists.apple.com

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Re: Send data from kernel to userspace with KEXT control ?
by David Gatwood 11 Sep '06

11 Sep '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Excellent!!! It is less ambiguity now for me. Could you point me to any documentation about ctl_enqueudata/clt_enqueuembuf? Is there any sample code about using kernel control to exchange data between kernelspace and userspace? They're documented in the KPI reference: David _______________________________________________ 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.… On Sep 9, 2006, at 12:03 PM, darwin-kernel-request(a)lists.apple.com wrote: Too bad that the NKE documentation fails to mention these functions? http://developer.apple.com/documentation/Darwin/Reference/ KPI_Reference/kern_control/index.html But you're right. They should be at least mentioned in the conceptual docs. I'll file a bug and fix this the next time I rev that document. This email sent to site_archiver(a)lists.apple.com

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sock_receive() returning error as EINVAL
by sanjay yaragatti 11 Sep '06

11 Sep '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=s1024; d=yahoo.co.in; h=Message-ID:Received:Date:From:Subject:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding; b=XjYwC6WYbFKS+KEvqSdl9hyuO8WM2w4yQseV+bjliqXVj/yuMv/EO/kufEaJsBmExKgS38ZwxwoUXn5mzYxqeMMZKRoG8FJgl4QZlTK2xWmhxJkZYRKdkWE8v1pkCDChL+CFNKVDJFSPyrzptXi6tV+5TclmT9rOmjtWYrGMLGg= ; Hi all, I am writing a kernel mode driver for a modem.I am using TCP implementation for the same. The API sock_receive() and sock_receivembuf() are both returning error no 22 i.e EINVAL (Invalid argument).Can anyone please tell me the reason for the same.. I am attaching the code below for reference.. Regards, Sanjay void socket_handler(socket_t so, void* context, int waitf) { UCHAR recv_data[MTU_SIZE + 3]; int ret = 0; struct msghdr recv_mesg; struct iovec recv_iov; size_t no_of_bytes_read = 0; struct sockaddr from; mbuf_t mp = 0; do { bzero(&from, sizeof(from)); bzero(&recv_mesg, sizeof(recv_mesg)); recv_mesg.msg_namelen = sizeof(from); recv_mesg.msg_name = &from; recv_iov.iov_base=(PUCHAR)recv_data; recv_iov.iov_len=sizeof(recv_data); recv_mesg.msg_iov=&recv_iov; ret = sock_receivembuf(so, &recv_mesg, &mp, MSG_DONTWAIT, &no_of_bytes_read) ; if((ret !=0 && ret != 35 )) { IOLog("Receive failed,Error number is %d\n",ret); return ; } if (no_of_bytes_read == 0) { sock_close(so); } if (no_of_bytes_read < 0) { EAL_ERR("Receive failed\n"); continue; } callback_func(context,recv_data, no_of_bytes_read); if (mp == 0) break; }while (1); } __________________________________________________________ Yahoo! India Answers: Share what you know. Learn something new http://in.answers.yahoo.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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Re: Send data from kernel to userspace with KEXT control ?
by NAHieu 09 Sep '06

09 Sep '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:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=cD8OTEaSxLsB/nAlHSspI8HKhysUBuePBuMiKORHzzMslWjg8LFT+mQVkq824+39GVmqrjuKSYxL94Ve+/eL1eRZKBeSRMItb+jTaHKK0byuuR8d1GQjYOcrHrLjhVdAdM8dSCHP2I5m/TLldA/SrD3HWWyFwtYaQ+C2uyRwEQM= Ah, never mind. I have found tcplognke, and look like that is what I need. Thank you, H Hi Josh, On 9/7/06, Josh Graessley <jgraessley(a)apple.com> wrote: > > Hello, > > ctl_enqueuedata and ctl_enqueuembuf will enqueue data in the receive > queue for you. When you call those functions, your user space process > that is presumably waiting for data, will be woken up, giving it a > chance to call recv to get to that data. Excellent!!! It is less ambiguity now for me. Could you point me to any documentation about ctl_enqueudata/clt_enqueuembuf? Is there any sample code about using kernel control to exchange data between kernelspace and userspace? Too bad that the NKE documentation fails to mention these functions? Many thanks. H > > I believe the point the documentation is making is that there is a > disconnect on the kernel to userspace side. When userspace calls to > the kernel, it all happens on one thread. There is a context switch to > go from userspace to kernel. When the kernel wants to pass data to > user space, it enqueues the data and any thread in userspace gets > kicked so it will call receive. > > -josh > > On Sep 6, 2006, at 2:25 AM, NAHieu wrote: > > > Hi, > > > > I have a kext that has some data to send out to userspace. After some > > time of investigations (great thanks to developers on this ML), I > > think it is a good idea to employ network stack for this job. > > > > To do that, I register a kernel control (ctl_register() function) in > > kernel, and have an application in userspace. The application will > > periodically send request for data to kernel. Inside kernel, I have a > > buffer, and it is necessary to send all the data from the buffer out > > to the userspace application. > > > > However, from the guide "Network kernel extensions programming > > guide", we read : > > " ..... the user process can communicate with the control using > > getsockopt, setsockopt, recv, and send on the socket. With the > > exception of recv (which is transparently handled with a queue), calls > > in user space to these functions result in a kernel-space call to the > > equivalent functions in the control, ctl_getopt_func, ctl_setopt_func, > > and ctl_send, respectively. > > ........" > > > > So it is not clear how we can handle receive function (recv) from > > inside kernel? > > I understand that to send data out (when client requests with recv()), > > I must handle the buffer for recv(), but I dont know how to do that. > > Too bad the documentation is quite ambiguity to me. > > > > Would anybody help me? > > > > Many 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.… On 9/9/06, NAHieu <nahieu(a)gmail.com> wrote: This email sent to site_archiver(a)lists.apple.com

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Re: Send data from kernel to userspace with KEXT control ?
by NAHieu 09 Sep '06

09 Sep '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:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=dZNXY9mjr+CsZ7ChWtaiiwba/FfUVmZSgW3QeWFoA378DClHrs+aAfZGmO7ADkU4fuNbbjsAQz3sUkEosgjHiq1oF2FVVJytfoTzKR5MGo95J0YlfQSiZkqXzrgOsvaOjTsWdX2wlyGRBsuqaLVu4o6f1lEhj298m1jBRumxrfE= Hi Josh, Hello, ctl_enqueuedata and ctl_enqueuembuf will enqueue data in the receive queue for you. When you call those functions, your user space process that is presumably waiting for data, will be woken up, giving it a chance to call recv to get to that data. Excellent!!! It is less ambiguity now for me. Could you point me to any documentation about ctl_enqueudata/clt_enqueuembuf? Is there any sample code about using kernel control to exchange data between kernelspace and userspace? Too bad that the NKE documentation fails to mention these functions? Many thanks. H I believe the point the documentation is making is that there is a disconnect on the kernel to userspace side. When userspace calls to the kernel, it all happens on one thread. There is a context switch to go from userspace to kernel. When the kernel wants to pass data to user space, it enqueues the data and any thread in userspace gets kicked so it will call receive. -josh On Sep 6, 2006, at 2:25 AM, NAHieu wrote: > Hi, > > I have a kext that has some data to send out to userspace. After some > time of investigations (great thanks to developers on this ML), I > think it is a good idea to employ network stack for this job. > > To do that, I register a kernel control (ctl_register() function) in > kernel, and have an application in userspace. The application will > periodically send request for data to kernel. Inside kernel, I have a > buffer, and it is necessary to send all the data from the buffer out > to the userspace application. > > However, from the guide "Network kernel extensions programming > guide", we read : > " ..... the user process can communicate with the control using > getsockopt, setsockopt, recv, and send on the socket. With the > exception of recv (which is transparently handled with a queue), calls > in user space to these functions result in a kernel-space call to the > equivalent functions in the control, ctl_getopt_func, ctl_setopt_func, > and ctl_send, respectively. > ........" > > So it is not clear how we can handle receive function (recv) from > inside kernel? > I understand that to send data out (when client requests with recv()), > I must handle the buffer for recv(), but I dont know how to do that. > Too bad the documentation is quite ambiguity to me. > > Would anybody help me? > > Many 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.… On 9/7/06, Josh Graessley <jgraessley(a)apple.com> wrote: This email sent to site_archiver(a)lists.apple.com

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Re: Get notified when a USB storage device connected?
by Kevin Elliott 07 Sep '06

07 Sep '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hi Jason, In the document "Accessing Hardware from Applications" there is a section on how to get notified when a device arrives or departs: http://developer.apple.com/documentation/DeviceDrivers/Conceptual/Accessing… Thank you a lot for this pointer. Anyway, is it possible to get notified from inside kernel? I have 2 choices: get notified to application, or to kernel. Kernel notified would be better for me. If it is impossible, I will go to the other way. Are you an IOKit kext? At 14:56 +0900 on 9/6/06, NAHieu wrote: On 9/6/06, Jason Seng <jseng(a)apple.com> wrote: If so, look at the method "setNotification" in IOService. The technique is very similar to what's described in "Accessing Hardware from Applications". -- ______________________________________________________ Arguing with an engineer is like wrestling with a pig in mud. After a while, you realize the pig is enjoying it. ______________________________________________________ Kevin Elliott <mailto:kelliott@mac.com> AIM/iChatAV: kelliott(a)mac.com (video chat available) ______________________________________________________ _______________________________________________ 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: Send data from kernel to userspace with KEXT control ?
by Josh Graessley 06 Sep '06

06 Sep '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hello, -josh On Sep 6, 2006, at 2:25 AM, NAHieu wrote: Hi, I have a kext that has some data to send out to userspace. After some time of investigations (great thanks to developers on this ML), I think it is a good idea to employ network stack for this job. To do that, I register a kernel control (ctl_register() function) in kernel, and have an application in userspace. The application will periodically send request for data to kernel. Inside kernel, I have a buffer, and it is necessary to send all the data from the buffer out to the userspace application. However, from the guide "Network kernel extensions programming guide", we read : " ..... the user process can communicate with the control using getsockopt, setsockopt, recv, and send on the socket. With the exception of recv (which is transparently handled with a queue), calls in user space to these functions result in a kernel-space call to the equivalent functions in the control, ctl_getopt_func, ctl_setopt_func, and ctl_send, respectively. ........" So it is not clear how we can handle receive function (recv) from inside kernel? I understand that to send data out (when client requests with recv()), I must handle the buffer for recv(), but I dont know how to do that. Too bad the documentation is quite ambiguity to me. Would anybody help me? Many thanks, H _______________________________________________ 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/jgraessley%40apple.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 ctl_enqueuedata and ctl_enqueuembuf will enqueue data in the receive queue for you. When you call those functions, your user space process that is presumably waiting for data, will be woken up, giving it a chance to call recv to get to that data. I believe the point the documentation is making is that there is a disconnect on the kernel to userspace side. When userspace calls to the kernel, it all happens on one thread. There is a context switch to go from userspace to kernel. When the kernel wants to pass data to user space, it enqueues the data and any thread in userspace gets kicked so it will call receive. This email sent to jgraessley(a)apple.com smime.p7s

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