/* * ReactOS kernel * Copyright (C) 1998, 1999, 2000, 2001 ReactOS Team * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ /* $Id$ * * PROJECT: ReactOS kernel * FILE: ntoskrnl/ke/process.c * PURPOSE: Microkernel process management * PROGRAMMER: David Welch (welch@cwcom.net) * PORTABILITY: No. * UPDATE HISTORY: * Created 22/05/98 */ /* INCLUDES *****************************************************************/ #include #include #include #include #define NDEBUG #include /* FUNCTIONS *****************************************************************/ /* * @implemented */ VOID STDCALL KeAttachProcess (PEPROCESS Process) { KIRQL oldlvl; PETHREAD CurrentThread; PULONG AttachedProcessPageDir; ULONG PageDir; DPRINT("KeAttachProcess(Process %x)\n",Process); CurrentThread = PsGetCurrentThread(); if (CurrentThread->OldProcess != NULL) { DbgPrint("Invalid attach (thread is already attached)\n"); KEBUGCHECK(0); } KeRaiseIrql(DISPATCH_LEVEL, &oldlvl); /* The stack of the current process may be located in a page which is not present in the page directory of the process we're attaching to. That would lead to a page fault when this function returns. However, since the processor can't call the page fault handler 'cause it can't push EIP on the stack, this will show up as a stack fault which will crash the entire system. To prevent this, make sure the page directory of the process we're attaching to is up-to-date. */ AttachedProcessPageDir = ExAllocatePageWithPhysPage(Process->Pcb.DirectoryTableBase); MmUpdateStackPageDir(AttachedProcessPageDir, &CurrentThread->Tcb); ExUnmapPage(AttachedProcessPageDir); CurrentThread->OldProcess = PsGetCurrentProcess(); CurrentThread->ThreadsProcess = Process; PageDir = Process->Pcb.DirectoryTableBase.u.LowPart; DPRINT("Switching process context to %x\n",PageDir) __asm__("movl %0,%%cr3\n\t" : /* no outputs */ : "r" (PageDir)); KeLowerIrql(oldlvl); } /* * @implemented */ VOID STDCALL KeDetachProcess (VOID) { KIRQL oldlvl; PETHREAD CurrentThread; ULONG PageDir; DPRINT("KeDetachProcess()\n"); CurrentThread = PsGetCurrentThread(); if (CurrentThread->OldProcess == NULL) { DbgPrint("Invalid detach (thread was not attached)\n"); KEBUGCHECK(0); } KeRaiseIrql(DISPATCH_LEVEL, &oldlvl); CurrentThread->ThreadsProcess = CurrentThread->OldProcess; CurrentThread->OldProcess = NULL; PageDir = CurrentThread->ThreadsProcess->Pcb.DirectoryTableBase.u.LowPart; __asm__("movl %0,%%cr3\n\t" : /* no inputs */ : "r" (PageDir)); KeLowerIrql(oldlvl); } /* EOF */