August 2003 - Darwin-kernel

system read blocks.
by Kaza Sudheer 05 Aug '03

05 Aug '03

Hi, I had created Named Pipes(FIFO's) "Xid" in process A and that is shared to B thr STDIN( 0 ). Process A and B communicates thr named pipes"Xid" Process "A " writes on "Xid" and process "B" reads from "Xid". My probelm is Lets say if Process "A" is terminated, still Process B waits on named pipe"Xid". It blocks on read system call. How to over come this probelm. Help plz Thanks KSudheer. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: Waking a socket call from an alternate thread.
by Wally Crooze 05 Aug '03

05 Aug '03

Jim Magee wrote: On Monday, July 28, 2003, at 3:39 AM, Wally Crooze wrote: Could somebody give me the supported mechanisms to wakeup/interrupt socket calls which will support all (hopefully) the cases that they could sleep. Within the kernel, the mechanism underlying all of these interruption mechanisms are represented by the Mach SPIs thread_abort() and thread_abort_safely(). They both interrupt a thread out of interruptible kernel operations. The former may leave the current operation in a non-restartable state. It is usually restricted to "kill -9" type operations where you don't care about restarting the current operation.The latter will only interrupt threads that can safely restart their current operations after handling the interruption. I've been doing a bit of playing with thread_abort_safely() to wake up from tsleep() and semaphore_wait(). semaphore_wait() returns a THREAD_ABORT result in the case of the thread_abort, but in the case of tsleep() no error is returned... it just wakes up. Since the tsleep() doesn't return an error how does the socket code know that it was interrupted /aborted? I would have expected EINTR to be returned from tsleep()... However, there is a "trick" to using these thread_abort() mechanisms within the kernel. Usually, the code that implements the return-to-user-space handling resets these conditions. For pure kernel threads, that path is not executed (and there is no published API to simulate it either). You could, however, work with a "borrowed/captured" user thread and return it user-space when EINTR is detected (to clear the interrupted condition). I don't understand this "trick". But as I said, use of these thread_abort() SPIs should be considered "at your own risk." No guarantees are made about their correctness (or even existence) from release to release. But enough code uses them (including Java runtime, Carbon thread manager, and BSD signals) at their core, that they are not likely to become invalid anytime soon. Are there plans to support thread "interruption" in the future? This is a real hinderance... and from what I've seen it appears that all threads sleep on a wait_queue which is easily accessible from within the kernel (not kext). -- Wally Crooze +-------------------------------------------------------+ | ,-_|\ Wally Crooze <wallycrooze(a)pobox.com> | | / \ | | \_,-._/ | | v | +-------------------------------------------------------+ _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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Re: KUNCUserNotificationDisplayFromBundle callback not being called
by Timothy Standing 04 Aug '03

04 Aug '03

Benedict - Apple apparently knows about this problem. It is due to a missing return statement in convert_port_to_UNDReply and has been entered in Apple's bug tracker as bug # 3358292. I don't believe this will be fixed in Panther so you might want to spawn a separate thread and just use KUNCUserNotificationDisplayAlert instead. (I know it doesn't offer all the functionality, but it works.) Tim Standing SoftRAID, LLC Message: 1 To: darwin-kernel(a)lists.apple.com From: Benedict Slaney <slaney(a)ihug.co.nz> Subject: KUNCUserNotificationDisplayFromBundle callback not being called Date: Mon, 4 Aug 2003 04:55:22 +1200 In my kext, KUNCUserNotificationDisplayFromBundle is not calling the function I provide a pointer to when the user clicks a button on the dialog it displays. here is the relevant part of the source in my kext: //globals KUNCUserNotificationCallBack dialogCallBack_p; void * dialogCallBack(int contextKey,int responseFlags,void *xmlData); //end globals //start relevant part of function dialogCallBack_p=dialogCallBack; ret=KUNCUserNotificationDisplayFromBundle(KUNCGetNotificationID(), "/System/Library/Extensions/SampleFilterScheme.kext", "Messages", "dict", "Password Message", "", dialogCallBack_p, context); //end relevant part of function However, the callback function "dialogCallBack" is not getting called when the user clicks a button on the dialog (or at all). This stops me from getting my required values from the dialog. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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KUNCUserNotificationDisplayFromBundle callback not being called
by Benedict Slaney 03 Aug '03

03 Aug '03

In my kext, KUNCUserNotificationDisplayFromBundle is not calling the function I provide a pointer to when the user clicks a button on the dialog it displays. here is the relevant part of the source in my kext: //globals KUNCUserNotificationCallBack dialogCallBack_p; void * dialogCallBack(int contextKey,int responseFlags,void *xmlData); //end globals //start relevant part of function dialogCallBack_p=dialogCallBack; ret=KUNCUserNotificationDisplayFromBundle(KUNCGetNotificationID(), "/System/Library/Extensions/SampleFilterScheme.kext", "Messages", "dict", "Password Message", "", dialogCallBack_p, context); //end relevant part of function However, the callback function "dialogCallBack" is not getting called when the user clicks a button on the dialog (or at all). This stops me from getting my required values from the dialog. This seems to be related to the UserNotificationCenter output below: Aug 4 04:17:43 thisones-Computer UserNotificationCenter[901]: Could not connect the action buttonPressed: to target of class NSApplication Aug 4 04:17:43 thisones-Computer last message repeated 3 times Finally, this is the dict I am using for the dialog: <?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd"> <plist version="1.0"> <dict> <key>Password Message</key> <dict> <key>Alternate Button Title</key> <string>Cancel</string> <key>OK Button Title</key> <string>OK</string> <key>Header</key> <string>Authentication Message</string> <key>Message</key> <string>Please enter a user name and password.</string> <key>Timeout</key> <string>0</string> <key>Alert Level</key> <string>Stop</string> <key>Text Field Strings</key> <array> <string>User Name:</string> <string>Password:</string> </array> <key>Password Fields</key> <array> <string>1</string> </array> <key>Blocking Message</key> <string>1</string> </dict> </dict> </plist> Any help will be very much appreciated. _______________________________________________ darwin-kernel mailing list | darwin-kernel(a)lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.

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