Re: interrupts in when in NT version
I have forgotten to cc this discussion to wine-devel. But who is interested can catch up from this mail. On Saturday 26 October 2002 14:07, Eric Pouech wrote: Could somebody answer/test if calling interrupt int 0x01 is allowed from a win32 program in WinNT environment? I would pretty like to know that! I don't think it is Should I write then a patch, which would deny calling of int 0x01 from win32 code when winver is NT? Would that be applied? the rule of thumb is: if there's a program which depends on this to be implemented, then yes patch will be applied otherwise, leave it as it is Tough all safedisc programs depend on this, I have decided not to make an official patch. The reason is that additional info is needed for a proper fix. Safedisc depends on that EXCEPTION_ACCESS_VIOLATION is returned on an int 0x01 call. But it should be checked what exceptions are raised on different windows versions when int 0x01 is called. And maybe the same should be done with other interrupts. It would be good if somebody could make that test program. Else I will keep the non proper fix. it was allowed on Win9x, and is used in this context IIRC as a ring 3 to ring 0 transition code (how to create a cheap call gate) How good it would be if I could understand what you are speaking about :( But could you explain what a call gate is? If it is too long, then dont bother tough... I'll try to make it short context: - i386 have 4 levels of privilege = ring 3 (less privilege) up to ring 0 - certain operations are only allowed at ring 0 (or 1) - user code runs in ring 3 - kernel code runs in ring 0 (to be exact, NT had been designed to have kernel in ring 0, and device drivers in ring 1, but this has been altered - some drivers run in ring 0 too) - you can always call into a less priviledged level (ring 0 = ring 3 for example) - the other way around requires what is known as call gates (ring 0 for example defines the entry points in some way) - most of the interrupt handlers run in ring 0 what the safedisc code was doing was: 0/ code is running in ring 3 1/ install an interrupt handler for division by zero (IIRC) 2/ trigger the division 3/ have the interrupt handler called, but this is done in ring 0, even if the code has been loaded from a user space program. here, in the interrupt handler, you can do any ring 0 operation you want that's why I called it a cheap call gate (no real call gate has been installed, and the code run in ring 0 isn't decided by the kernel but the app) NT doesn't allow this to run. step 1 is not allowed (only the kernel can decide to change an interrupt handler, which makes lots of sense) Thanks for the detailed explanation. And for completeness I will include here the explanation of Laurent Pinchart why a safedisc program calls int 0x01 : - the last attempt to detect a debugger uses int 0x01 (enter SMM/ICE mode), which checks if an external hardware emulator is connected to the processor. I haven't been able to understand what the code is supposed to do. Regards Zsolt
Re: interrupts in when in NT version
Tough all safedisc programs depend on this, I have decided not to make an official patch. The reason is that additional info is needed for a proper fix. Safedisc depends on that EXCEPTION_ACCESS_VIOLATION is returned on an int 0x01 call. But it should be checked what exceptions are raised on different windows versions when int 0x01 is called. And maybe the same should be done with other interrupts. It would be good if somebody could make that test program. Else I will keep the non proper fix. You may think me a rube, but I just made a test program that calls an arbitrary interrupt and prints the exception information. I don't set up any registers, so perhaps it generates an exception when it ought not in some cases, but anyone else is free to improve it. Source and a VC6-compiled MSVCRT-using version, along with results for all 255 interrupts on Windows XP Professional, is here: http://petra.trnty.edu/~jhohm/intexcep.zip
Re: interrupts in when in NT version
On Saturday 26 October 2002 17:36, John K. Hohm wrote: Tough all safedisc programs depend on this, I have decided not to make an official patch. The reason is that additional info is needed for a proper fix. Safedisc depends on that EXCEPTION_ACCESS_VIOLATION is returned on an int 0x01 call. But it should be checked what exceptions are raised on different windows versions when int 0x01 is called. And maybe the same should be done with other interrupts. It would be good if somebody could make that test program. Else I will keep the non proper fix. You may think me a rube, but I just made a test program that calls an What do you mean by rube? According to my dictionary rube means: rube n.: AmE slang someone, usually from the country, who has no experience of other places and thinks in a simple way I dont understand while would you be a rube? arbitrary interrupt and prints the exception information. I don't set up any registers, so perhaps it generates an exception when it ought not in some cases, but anyone else is free to improve it. Source and a VC6-compiled MSVCRT-using version, along with results for all 255 interrupts on Windows XP Professional, is here: http://petra.trnty.edu/~jhohm/intexcep.zip Thanks for your work. It proves my assumptions at least in the winXP case, and I assume it is the same in nt40. It would be nice if somebody could run this program on a win9x system. (I only have win2k available here). Thanks Zsolt
Re: interrupts in when in NT version
On Thu, Oct 24, 2002 at 12:26:15PM +0200, Zsolt Rizsanyi wrote: But the recent interrupt changes tend to cause cvs conflicts and to break it. This patch is supposed to work only if winver is nt40 so very probably this applies only to NT. ... I would like if this could be fixed properly and that would work with the safedisk patch, if thats possible. and on 28 May 2002 18:58:51 -0700, Alexandre wrote: Laurent Pinchart [EMAIL PROTECTED] writes: There are two patches in there. The first one sets a fault handler for the SharedUserData. This looks fine to me, and will probably be applied when memory/emulate.c will be applied. It still isn't clear to me why you need a fault handler at all. You could simply put the right data into it at allocation time. The second one has been written by Alexandre to fix the process suspension at creation time. Once again I'd like to hear from him to know what he doesn't like about the code, as he's the one who wrote it :-) The main problem is that it isn't generic enough, it only applies to the create process request but other requests have the same problem and should be fixed too. I'll work on a more general solution. I looks like the more general solution was never done due to time/lack of nagging reasons? Ciao Jörg -- Joerg Mayer [EMAIL PROTECTED] I found out that pro means instead of (as in proconsul). Now I know what proactive means.
Re: interrupts in when in NT version
Joerg Mayer [EMAIL PROTECTED] writes: and on 28 May 2002 18:58:51 -0700, Alexandre wrote: The main problem is that it isn't generic enough, it only applies to the create process request but other requests have the same problem and should be fixed too. I'll work on a more general solution. I looks like the more general solution was never done due to time/lack of nagging reasons? Well it's part of the finalize server protocol task that's supposed to be done for 1.0. So it will get done eventually... -- Alexandre Julliard [EMAIL PROTECTED]
Re: interrupts in when in NT version
On Friday 25 October 2002 13:46, Joerg Mayer wrote: On Thu, Oct 24, 2002 at 12:26:15PM +0200, Zsolt Rizsanyi wrote: But the recent interrupt changes tend to cause cvs conflicts and to break it. This patch is supposed to work only if winver is nt40 so very probably this applies only to NT. ... I would like if this could be fixed properly and that would work with the safedisk patch, if thats possible. and on 28 May 2002 18:58:51 -0700, Alexandre wrote: Laurent Pinchart [EMAIL PROTECTED] writes: There are two patches in there. The first one sets a fault handler for the SharedUserData. This looks fine to me, and will probably be applied when memory/emulate.c will be applied. It still isn't clear to me why you need a fault handler at all. You could simply put the right data into it at allocation time. The second one has been written by Alexandre to fix the process suspension at creation time. Once again I'd like to hear from him to know what he doesn't like about the code, as he's the one who wrote it :-) The main problem is that it isn't generic enough, it only applies to the create process request but other requests have the same problem and should be fixed too. I'll work on a more general solution. I looks like the more general solution was never done due to time/lack of nagging reasons? Yes. Alexandre has not yet did the proper fix for the problems on thread suspension. I dont really know the reasons, but maybe it was the lack of nagging :) I think I'm the only one who uses this safedisc patch, and I was not too loud about that. But this (thread suspension) has nothing to do with interrupts. As much as I know the int 0x01 is called by the program to test if it has a sane environment (check to see if the program is not debugged). Could somebody answer/test if calling interrupt int 0x01 is allowed from a win32 program in WinNT environment? I would pretty like to know that! Thanks Zsolt
Re: interrupts in when in NT version
Rizsanyi Zsolt a écrit : Could somebody answer/test if calling interrupt int 0x01 is allowed from a win32 program in WinNT environment? I would pretty like to know that! I don't think it is it was allowed on Win9x, and is used in this context IIRC as a ring 3 to ring 0 transition code (how to create a cheap call gate) A+
