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2afe9d1fd6
This commit got completely out of control. Added the fork(), getpid(), getppid(), sleep(), usleep() system calls, and aliases in the Maxsi:: namespace. Fixed a bug where zero-byte allocation would fail. Worked on the DescriptorTable class which now works and can fork. Got rid of some massive print-registers statements and replaced them with the portable InterruptRegisters::LogRegisters() function. Removed the SysExecuteOld function and replaced it with Process::Execute(). Rewrote the boot sequence in kernel.cpp such that it now loads the system idle process 'idle' as PID 0, and the initization process 'init' as PID 1. Rewrote the SIGINT hack. Processes now maintain a family-tree structure and keep track of their threads. PIDs are now allocated using a simple hack. Virtual memory per-process can now be allocated using a simple hack. Processes can now be forked. Fixed the Process::Execute function such that it now resets the stack pointer to where the stack actually is - not just a magic value. Removed the old and ugly Process::_endcodesection hack. Rewrote the scheduler into a much cleaner and faster version. Debug code is now moved to designated functions. The noop kernel-thread has been replaced by a simple user-space infinite-loop program 'idle'. The Thread class has been seperated from the Scheduler except in Scheduler- related code. Thread::{Save,Load}Registers has been improved and has been moved to $(CPU)/thread.cpp. Threads can now be forked. A new CreateThread function creates threads properly and portably. Added a MicrosecondsSinceBoot() function. Fixed a crucial bug in MemoryManagement::Fork(). Added an 'idle' user-space program that is a noop infinite loop, which is used by the scheduler when there is nothing to do. Rewrote the 'init' program such that it now forks off a shell, instead of becoming the shell. Added the $$ (current PID) and $PPID (parent PPID) variables to the shell.
321 lines
6.9 KiB
C++
321 lines
6.9 KiB
C++
/******************************************************************************
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COPYRIGHT(C) JONAS 'SORTIE' TERMANSEN 2011.
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This file is part of Sortix.
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Sortix is free software: you can redistribute it and/or modify it under the
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terms of the GNU General Public License as published by the Free Software
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Foundation, either version 3 of the License, or (at your option) any later
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version.
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Sortix is distributed in the hope that it will be useful, but WITHOUT ANY
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WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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details.
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You should have received a copy of the GNU General Public License along
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with Sortix. If not, see <http://www.gnu.org/licenses/>.
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process.cpp
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Describes a process belonging to a subsystem.
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******************************************************************************/
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#include "platform.h"
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#include <libmaxsi/memory.h>
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#include <libmaxsi/string.h>
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#include "thread.h"
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#include "process.h"
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#include "memorymanagement.h"
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#include "initrd.h"
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#include "elf.h"
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#include "syscall.h"
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using namespace Maxsi;
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namespace Sortix
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{
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bool ProcessSegment::Intersects(ProcessSegment* segments)
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{
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for ( ProcessSegment* tmp = segments; tmp != NULL; tmp = tmp->next )
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{
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if ( tmp->position < position + size &&
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position < tmp->position + tmp->size )
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{
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return true;
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}
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}
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if ( next ) { return next->Intersects(segments); }
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return false;
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}
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ProcessSegment* ProcessSegment::Fork()
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{
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ProcessSegment* nextclone = NULL;
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if ( next )
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{
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nextclone = next->Fork();
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if ( nextclone == NULL ) { return NULL; }
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}
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ProcessSegment* clone = new ProcessSegment();
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if ( clone == NULL )
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{
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while ( nextclone != NULL )
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{
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ProcessSegment* todelete = nextclone;
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nextclone = nextclone->next;
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delete todelete;
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}
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return NULL;
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}
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next->prev = nextclone;
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clone->next = nextclone;
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clone->position = position;
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clone->size = size;
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return clone;
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}
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Process::Process()
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{
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addrspace = 0;
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segments = NULL;
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sigint = false;
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parent = NULL;
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prevsibling = NULL;
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nextsibling = NULL;
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firstchild = NULL;
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firstthread = NULL;
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mmapfrom = 0x80000000UL;
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pid = AllocatePID();
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}
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Process::~Process()
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{
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ResetAddressSpace();
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// Avoid memory leaks.
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ASSERT(segments == NULL);
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// TODO: Delete address space!
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}
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void Process::ResetAddressSpace()
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{
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ProcessSegment* tmp = segments;
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while ( tmp != NULL )
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{
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Memory::UnmapRangeUser(tmp->position, tmp->size);
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ProcessSegment* todelete = tmp;
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tmp = tmp->next;
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delete todelete;
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}
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segments = NULL;
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}
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Process* Process::Fork()
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{
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ASSERT(CurrentProcess() == this);
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Process* clone = new Process;
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if ( !clone ) { return NULL; }
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ProcessSegment* clonesegments = NULL;
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// Fork the segment list.
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if ( segments )
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{
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clonesegments = segments->Fork();
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if ( clonesegments == NULL ) { delete clone; return NULL; }
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}
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// Fork address-space here and copy memory somehow.
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clone->addrspace = Memory::Fork();
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if ( !clone->addrspace )
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{
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// Delete the segment list, since they are currently bogus.
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ProcessSegment* tmp = clonesegments;
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while ( tmp != NULL )
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{
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ProcessSegment* todelete = tmp;
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tmp = tmp->next;
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delete todelete;
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}
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delete clone; return NULL;
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}
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// Now it's too late to clean up here, if anything goes wrong, the
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// cloned process should be queued for destruction.
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clone->segments = clonesegments;
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// Remember the relation to the child process.
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clone->parent = this;
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if ( firstchild )
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{
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firstchild->prevsibling = clone;
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clone->nextsibling = firstchild;
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firstchild = clone;
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}
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else
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{
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firstchild = clone;
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}
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// Fork the file descriptors.
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if ( !descriptors.Fork(&clone->descriptors) )
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{
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Panic("No error handling when forking FDs fails!");
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}
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Thread* clonethreads = ForkThreads(clone);
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if ( !clonethreads )
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{
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Panic("No error handling when forking threads fails!");
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}
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clone->firstthread = clonethreads;
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// Copy variables.
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clone->mmapfrom = mmapfrom;
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// Now that the cloned process is fully created, we need to signal to
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// its threads that they should insert themselves into the scheduler.
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for ( Thread* tmp = clonethreads; tmp != NULL; tmp = tmp->nextsibling )
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{
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tmp->Ready();
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}
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return clone;
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}
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Thread* Process::ForkThreads(Process* processclone)
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{
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Thread* result = NULL;
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Thread* tmpclone = NULL;
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for ( Thread* tmp = firstthread; tmp != NULL; tmp = tmp->nextsibling )
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{
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Thread* clonethread = tmp->Fork();
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if ( clonethread == NULL )
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{
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while ( tmpclone != NULL )
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{
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Thread* todelete = tmpclone;
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tmpclone = tmpclone->prevsibling;
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delete todelete;
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}
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return NULL;
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}
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clonethread->process = processclone;
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if ( result == NULL ) { result = clonethread; }
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if ( tmpclone != NULL )
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{
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tmpclone->nextsibling = clonethread;
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clonethread->prevsibling = tmpclone;
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}
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tmpclone = clonethread;
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}
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return result;
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}
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void Process::ResetForExecute()
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{
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// TODO: Delete all threads and their stacks.
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// TODO: Unmap any process memory segments.
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}
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int Process::Execute(const char* programname, CPU::InterruptRegisters* regs)
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{
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size_t programsize = 0;
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byte* program = InitRD::Open(programname, &programsize);
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if ( !program ) { return -1; }
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addr_t entry = ELF::Construct(CurrentProcess(), program, programsize);
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if ( !entry )
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{
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Log::PrintF("Could not create process '%s'", programname);
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if ( String::Compare(programname, "sh") == 0 )
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{
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Panic("Couldn't create the shell process");
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}
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return Execute("sh", regs);
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}
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// TODO: This may be an ugly hack!
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// TODO: Move this to x86/process.cpp.
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regs->eip = entry;
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regs->useresp = CurrentThread()->stackpos + CurrentThread()->stacksize;
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regs->ebp = CurrentThread()->stackpos + CurrentThread()->stacksize;
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return 0;
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}
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int SysExecute(const char* programname)
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{
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// TODO: Validate that filepath is a user-space readable string!
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// This is a hacky way to set up the thread!
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return Process::Execute(programname, Syscall::InterruptRegs());
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}
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pid_t SysFork()
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{
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// Prepare the state of the clone.
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Syscall::SyscallRegs()->result = 0;
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CurrentThread()->SaveRegisters(Syscall::InterruptRegs());
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Process* clone = CurrentProcess()->Fork();
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if ( !clone ) { return -1; }
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return clone->pid;
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}
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pid_t SysGetPID()
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{
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return CurrentProcess()->pid;
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}
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pid_t SysGetParentPID()
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{
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Process* parent = CurrentProcess()->parent;
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if ( !parent ) { return -1; }
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return parent->pid;
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}
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pid_t nextpidtoallocate;
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pid_t Process::AllocatePID()
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{
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return nextpidtoallocate++;
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}
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void Process::Init()
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{
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Syscall::Register(SYSCALL_EXEC, (void*) SysExecute);
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Syscall::Register(SYSCALL_FORK, (void*) SysFork);
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Syscall::Register(SYSCALL_GETPID, (void*) SysGetPID);
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Syscall::Register(SYSCALL_GETPPID, (void*) SysGetParentPID);
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nextpidtoallocate = 0;
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}
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addr_t Process::AllocVirtualAddr(size_t size)
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{
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return (mmapfrom -= size);
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}
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}
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