May 2006 - Darwin-kernel - lists.apple.com

Get IOUSBInterface from IOUSBDevice functionality needs your expert review!!
by Chinki 29 May '06

29 May '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; b=Ne+l7n+REEUXdI8K+8xquxRqyK5xPRjTqw4JJMF6Po5rIb504HsHZrspk16UsptzTeB+oJ1BaNCLicMWIZuzPqOk0M2haAOLPgSEDaDXeK6SlavKvC+mELVl/xl8XKW7/azH/ScxnU6YilHxN6buD1/MA66lH8hZgY3evN1dhFk= _______________________________________________ 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

1 0

Re: Communicating from a KEXT to a userland process
by Michael Smith 28 May '06

28 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On May 28, 2006, at 12:39 PM, Bruce Fancher 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.… Thanks for the response, but oy, that looks really complicated. All I want to do is have my kext provide the paths of the files it intercepts through kauth to my daemon. Is there any simpler way to have the daemon call into the kext than basically writing an IOKit device driver? Take a look at kernel control sockets and sysctl. The latter is a little awkward but relatively simple, the former is a little cleaner and has the benefit of being KPI. This email sent to site_archiver(a)lists.apple.com

1 0

RE: Communicating from a KEXT to a userland process
by Bruce Fancher 28 May '06

28 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: AcaCc+WCInQrBQYBQQy2njX0W5VrJwAGqMRw Thanks. I'll check this out. Bruce -----Original Message----- From: John Dalgliesh [mailto:johnd@defyne.org] Sent: Sunday, May 28, 2006 12:29 PM To: Bruce Fancher Cc: darwin-kernel(a)lists.apple.com Subject: Re: Communicating from a KEXT to a userland process Hi Bruce, On Sun, 28 May 2006, Bruce Fancher wrote: ... > > The problem I'm having is figuring out how to communicate back out > from my Kext to userland. TN2127 uses the example of an anti-virus > program, which is conceptually similar to what I'm trying to do, and > specifically suggests having the Kext pass a request to a user space > daemon. However it doesn't provide any suggestion or example wrt > exactly how I might go about communicating from the Kext to said daemon. > ... > > Oh, and I also tried looking into using Mach ports, but again I > couldn't find any examples or documentation. > > So, first of all what mechanism should I be using, and second, how do > I use I use it? Any example code anyone can provide would be very welcome. I believe that the general rule is: if you can form your daemon<->kext relationship in such a way that the daemon makes blocking calls into the kext, and the kext repsonds to them when it has something to send, then you should do this as you will be a much happier person and lead a long and fulfilling life. Or if you just want to send small messages (<64 bytes) then the argument of IOService::message does propagate nicely to userspace via an IONotificationPort. That said, here is an example of the daemon calling the kext back: :) When I encountered this situation the Mach ports route looked promising to me, and after much perseverence I managed to get it to work. You can find a working example in the file Drivers/UDMUtils/UDMResourceFile.cpp in the CVS repository on this page: <http://www.defyne.org/dvb/> (under the 'Development' section). The userspace side is in udmarket/ResourceFileRelay/ResourceFileRelay.mm. This code is a kext+daemon that allows you to read (and write) files from the kernel, for loading firmware or config files, etc. Some of the details are probably not very kosher although I believe the design (now) is, so YMMV. > Thanks, > > Bruce Fancher {P^/ _______________________________________________ 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

1 0

RE: Communicating from a KEXT to a userland process
by Bruce Fancher 28 May '06

28 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: AcaCcTIYYuxTluVGQ/2MkChmZCXw/wAHMsfA Thanks for the response, but oy, that looks really complicated. All I want to do is have my kext provide the paths of the files it intercepts through kauth to my daemon. Is there any simpler way to have the daemon call into the kext than basically writing an IOKit device driver? Thanks, Bruce -----Original Message----- From: Michael Cashwell [mailto:mboards@prograde.net] Sent: Sunday, May 28, 2006 12:10 PM To: Bruce Fancher Cc: darwin-kernel(a)lists.apple.com Subject: Re: Communicating from a KEXT to a userland process On May 28, 2006, at 11:33 AM, Bruce Fancher wrote: > This document: > > <http://developer.apple.com/documentation/Darwin/Conceptual/ > KernelProgramming/boundaries/chapter_14_section_1.html> > > describes a number of mechanisms for communication between the kernel > and userland, but is oriented towards calling from userland into the > kernel, which is exactly the opposite of what I'm trying to do. Perhaps not. Keep in mind that the kernel is supposed to be passive. It's supposed to only respond to userland requests (and to handle the hardware). This means that it's a but no-no to try to coax the kernel (eg: a kernal thread) to "call out" to userland. The approved way to handle this is to have a userland app call into the kernel (via whatever means you want, but a User Client sounds appropriate) and have that thread block until such time as it has something useful to return to the app. The key here is that you never have kernel threads running code that is not part of the kernel. If having your userland thread block, just create a thread for this purpose. It then feels like the kernel calls out to you when really it's just a thread the app has loaned to the kernel coming back to it. Here's one good example doc I found a while back. It covers these ideas pretty well. <http://developer.apple.com/documentation/DeviceDrivers/Conceptual/ WritingDeviceDriver/MakingHWAccessible/chapter_5_section_3.html> Good luck! -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

1 0

Re: Communicating from a KEXT to a userland process
by John Dalgliesh 28 May '06

28 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Hi Bruce, On Sun, 28 May 2006, Bruce Fancher wrote: ... The problem I'm having is figuring out how to communicate back out from my Kext to userland. TN2127 uses the example of an anti-virus program, which is conceptually similar to what I'm trying to do, and specifically suggests having the Kext pass a request to a user space daemon. However it doesn't provide any suggestion or example wrt exactly how I might go about communicating from the Kext to said daemon. Oh, and I also tried looking into using Mach ports, but again I couldn't find any examples or documentation. So, first of all what mechanism should I be using, and second, how do I use I use it? Any example code anyone can provide would be very welcome. That said, here is an example of the daemon calling the kext back: :) The userspace side is in udmarket/ResourceFileRelay/ResourceFileRelay.mm. Thanks, {P^/ _______________________________________________ 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 believe that the general rule is: if you can form your daemon<->kext relationship in such a way that the daemon makes blocking calls into the kext, and the kext repsonds to them when it has something to send, then you should do this as you will be a much happier person and lead a long and fulfilling life. Or if you just want to send small messages (<64 bytes) then the argument of IOService::message does propagate nicely to userspace via an IONotificationPort. When I encountered this situation the Mach ports route looked promising to me, and after much perseverence I managed to get it to work. You can find a working example in the file Drivers/UDMUtils/UDMResourceFile.cpp in the CVS repository on this page: <http://www.defyne.org/dvb/> (under the 'Development' section). This code is a kext+daemon that allows you to read (and write) files from the kernel, for loading firmware or config files, etc. Some of the details are probably not very kosher although I believe the design (now) is, so YMMV. Bruce Fancher This email sent to site_archiver(a)lists.apple.com

1 0

Re: Communicating from a KEXT to a userland process
by Michael Cashwell 28 May '06

28 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com On May 28, 2006, at 11:33 AM, Bruce Fancher wrote: This document: Good luck! -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.… <http://developer.apple.com/documentation/Darwin/Conceptual/ KernelProgramming/boundaries/chapter_14_section_1.html> describes a number of mechanisms for communication between the kernel and userland, but is oriented towards calling from userland into the kernel, which is exactly the opposite of what I'm trying to do. Perhaps not. Keep in mind that the kernel is supposed to be passive. It's supposed to only respond to userland requests (and to handle the hardware). This means that it's a but no-no to try to coax the kernel (eg: a kernal thread) to "call out" to userland. The approved way to handle this is to have a userland app call into the kernel (via whatever means you want, but a User Client sounds appropriate) and have that thread block until such time as it has something useful to return to the app. The key here is that you never have kernel threads running code that is not part of the kernel. If having your userland thread block, just create a thread for this purpose. It then feels like the kernel calls out to you when really it's just a thread the app has loaned to the kernel coming back to it. Here's one good example doc I found a while back. It covers these ideas pretty well. <http://developer.apple.com/documentation/DeviceDrivers/Conceptual/ WritingDeviceDriver/MakingHWAccessible/chapter_5_section_3.html> This email sent to site_archiver(a)lists.apple.com

1 0

Communicating from a KEXT to a userland process
by Bruce Fancher 28 May '06

28 May '06

site_archiver(a)lists.apple.com Delivered-To: darwin-kernel(a)lists.apple.com Thread-index: AcaCan6sRzOd+ntfTm2+XFy36oa9iwAABQIw I'm trying to write a small Kext that uses the Kauth apis to register for file events and then notifies a userland program to take action when files of certain types appear. Using Kauth itself seems to be no problem. I just followed the instructions and examples here: http://developer.apple.com/technotes/tn2005/tn2127.html and http://developer.apple.com/samplecode/KauthORama/index.html The problem I'm having is figuring out how to communicate back out from my Kext to userland. TN2127 uses the example of an anti-virus program, which is conceptually similar to what I'm trying to do, and specifically suggests having the Kext pass a request to a user space daemon. However it doesn't provide any suggestion or example wrt exactly how I might go about communicating from the Kext to said daemon. This document: http://developer.apple.com/documentation/Darwin/Conceptual/KernelProgramming /boundaries/chapter_14_section_1.html describes a number of mechanisms for communication between the kernel and userland, but is oriented towards calling from userland into the kernel, which is exactly the opposite of what I'm trying to do. Meanwhile, this document: http://developer.apple.com/documentation/Darwin/Conceptual/NKEConceptual/con trol/chapter_3_section_3.html suggests using kev_message_post to send notifications from an NKE to a userland process. However it doesn't provide any examples or documentation for using said API, and a Google search for "kev_message_post" returns exactly one result: the same document on Apple's web site. I also looked at using BSD sockets, but the only documentation I could find on opening a socket from the kernel is here: http://developer.apple.com/documentation/Darwin/Reference/KPI_Reference/kpi_ socket/index.html Doesn't really explain how to use the apis or fill in the structs you need to pass in, just lists the methods and the parameters they take. I did find one example using this api, here: http://darwinsource.opendarwin.org/10.4.2/webdavfs-214.1/webdav_fs.kextproj/ webdav_fs.kmodproj/webdav_vnops.c But it's pretty obscure for someone who's experience with bsd networking is limited to bind(), listen(), accept(), read(), etc. I have no idea what a msghdr or an iovec is, and there doesn't seem to be much in the way of documentation or examples out there. Oh, and I also tried looking into using Mach ports, but again I couldn't find any examples or documentation. So, first of all what mechanism should I be using, and second, how do I use I use it? Any example code anyone can provide would be very welcome. Thanks, Bruce Fancher _______________________________________________ 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

1 0

Re: Write/Read Bulk communication process in KEXT. How?
by Chinki 26 May '06

26 May '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:references; b=BY9iS37YPRFe675O5s3TKZPaIJ/6NM2vxnAx+k6lDybEbHqywdgYN8GKcZ+sVGcclTgvpxwGJLmFBlBU5ZjoFS/5tDpaUxrZrx0eXXsugMCjtO8SH/8cKFBVAUCgWIdZ6nixfV1Q6GwPEc0RBSG3+gqGZVtapAuCAnmM+UHx55A= _______________________________________________ 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

1 0

Re: Write/Read Bulk communication process in KEXT. How?
by Michael Smith 25 May '06

25 May '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

1 0

Re: Write/Read Bulk communication process in KEXT. How?
by Chinki 25 May '06

25 May '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:references; b=Ou9DKj7+7C6EEO1HRCbrxaC6DThQNsvY8EpFaPaVp68FRHHljxYNJnORIsRyMX1+cPdCwm0nlQKqMSHwF+81yuCuHGRm5yNo2juru/HQ/tTa4AaTcFp0z0u13nxaKOSBNLx9836YGu2545+6BaOIMmM8psV0v4bLi6CjTdguZFg= _______________________________________________ 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

1 0