Pardon the big ass-commit, this took months to develop and debug and the refactoring got so far that a clean merge became impossible. The good news is that this commit does quite a bit of cleaning up and generally improves the kernel quality. This makes the kernel fully pre-emptive and multithreaded. This was done by rewriting the interrupt code, the scheduler, introducing new threading primitives, and rewriting large parts of the kernel. During the past few commits the kernel has had its device drivers thread secured; this commit thread secures large parts of the core kernel. There still remains some parts of the kernel that is _not_ thread secured, but this is not a problem at this point. Each user-space thread has an associated kernel stack that it uses when it goes into kernel mode. This stack is by default 8 KiB since that value works for me and is also used by Linux. Strange things tends to happen on x86 in case of a stack overflow - there is no ideal way to catch such a situation right now. The system call conventions were changed, too. The %edx register is now used to provide the errno value of the call, instead of the kernel writing it into a registered global variable. The system call code has also been updated to better reflect the native calling conventions: not all registers have to be preserved. This makes system calls faster and simplifies the assembly. In the kernel, there is no longer the event.h header or the hacky method of 'resuming system calls' that closely resembles cooperative multitasking. If a system call wants to block, it should just block. The signal handling was also improved significantly. At this point, signals cannot interrupt kernel threads (but can always interrupt user-space threads if enabled), which introduces some problems with how a SIGINT could interrupt a blocking read, for instance. This commit introduces and uses a number of new primitives such as kthread_lock_mutex_signal() that attempts to get the lock but fails if a signal is pending. In this manner, the kernel is safer as kernel threads cannot be shut down inconveniently, but in return for complexity as blocking operations must check they if they should fail. Process exiting has also been refactored significantly. The _exit(2) system call sets the exit code and sends SIGKILL to all the threads in the process. Once all the threads have cleaned themselves up and exited, a worker thread calls the process's LastPrayer() method that unmaps memory, deletes the address space, notifies the parent, etc. This provides a very robust way to terminate processes as even half-constructed processes (during a failing fork for instance) can be gracefully terminated. I have introduced a number of kernel threads to help avoid threading problems and simplify kernel design. For instance, there is now a functional generic kernel worker thread that any kernel thread can schedule jobs for. Interrupt handlers run with interrupts off (hence they cannot call kthread_ functions as it may deadlock the system if another thread holds the lock) therefore they cannot use the standard kernel worker threads. Instead, they use a special purpose interrupt worker thread that works much like the generic one expect that interrupt handlers can safely queue work with interrupts off. Note that this also means that interrupt handlers cannot allocate memory or print to the kernel log/screen as such mechanisms uses locks. I'll introduce a lock free algorithm for such cases later on. The boot process has also changed. The original kernel init thread in kernel.cpp creates a new bootstrap thread and becomes the system idle thread. Note that pid=0 now means the kernel, as there is no longer a system idle process. The bootstrap thread launches all the kernel worker threads and then creates a new process and loads /bin/init into it and then creates a thread in pid=1, which starts the system. The bootstrap thread then quietly waits for pid=1 to exit after which it shuts down/reboots/panics the system. In general, the introduction of race conditions and dead locks have forced me to revise a lot of the design and make sure it was thread secure. Since early parts of the kernel was quite hacky, I had to refactor such code. So it seems that the risk of dead locks forces me to write better code. Note that a real preemptive multithreaded kernel simplifies the construction of blocking system calls. My hope is that this will trigger a clean up of the filesystem code that current is almost beyond repair. Almost all of the kernel was modified during this refactoring. To the extent possible, these changes have been backported to older non-multithreaded kernel, but many changes were tightly coupled and went into this commit. Of interest is the implementation of the kthread_ api based on the design of pthreads; this library allows easy synchronization mechanisms and includes C++-style scoped locks. This commit also introduces new worker threads and tested mechanisms for interrupt handlers to schedule work in a kernel worker thread. A lot of code have been rewritten from scratch and has become a lot more stable and correct. Share and enjoy!
855 lines
22 KiB
C++
855 lines
22 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2011, 2012.
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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 with
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Sortix. If not, see <http://www.gnu.org/licenses/>.
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process.cpp
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A named collection of threads.
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*******************************************************************************/
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#include <sortix/kernel/platform.h>
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#include <sortix/kernel/kthread.h>
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#include <sortix/kernel/worker.h>
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#include <sortix/kernel/memorymanagement.h>
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#include <sortix/signal.h>
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#include <sortix/unistd.h>
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#include <sortix/fork.h>
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#include <sortix/mman.h>
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#include <libmaxsi/error.h>
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#include <libmaxsi/memory.h>
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#include <libmaxsi/string.h>
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#include <libmaxsi/sortedlist.h>
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#include "thread.h"
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#include "process.h"
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#include "device.h"
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#include "stream.h"
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#include "filesystem.h"
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#include "directory.h"
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#include "scheduler.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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if ( nextclone )
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nextclone->prev = clone;
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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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parent = NULL;
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prevsibling = NULL;
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nextsibling = NULL;
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firstchild = NULL;
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zombiechild = NULL;
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parentlock = KTHREAD_MUTEX_INITIALIZER;
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childlock = KTHREAD_MUTEX_INITIALIZER;
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zombiecond = KTHREAD_COND_INITIALIZER;
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zombiewaiting = 0;
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iszombie = false;
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nozombify = false;
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firstthread = NULL;
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threadlock = KTHREAD_MUTEX_INITIALIZER;
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workingdir = NULL;
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mmapfrom = 0x80000000UL;
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exitstatus = -1;
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pid = AllocatePID();
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Put(this);
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}
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Process::~Process()
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{
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ASSERT(!zombiechild);
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ASSERT(!firstchild);
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ASSERT(!addrspace);
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ASSERT(!segments);
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Remove(this);
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delete[] workingdir;
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}
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void Process__OnLastThreadExit(void* user);
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void Process::OnThreadDestruction(Thread* thread)
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{
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ASSERT(thread->process == this);
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kthread_mutex_lock(&threadlock);
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if ( thread->prevsibling )
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thread->prevsibling->nextsibling = thread->nextsibling;
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if ( thread->nextsibling )
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thread->nextsibling->prevsibling = thread->prevsibling;
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if ( thread == firstthread )
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firstthread = thread->nextsibling;
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if ( firstthread )
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firstthread->prevsibling = NULL;
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thread->prevsibling = thread->nextsibling = NULL;
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bool threadsleft = firstthread;
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kthread_mutex_unlock(&threadlock);
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// We are called from the threads destructor, let it finish before we
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// we handle the situation by killing ourselves.
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if ( !threadsleft )
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ScheduleDeath();
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}
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void Process::ScheduleDeath()
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{
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// All our threads must have exited at this point.
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ASSERT(!firstthread);
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Worker::Schedule(Process__OnLastThreadExit, this);
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}
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// Useful for killing a partially constructed process without waiting for
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// it to die and garbage collect its zombie. It is not safe to access this
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// process after this call as another thread may garbage collect it.
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void Process::AbortConstruction()
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{
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nozombify = true;
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ScheduleDeath();
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}
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void Process__OnLastThreadExit(void* user)
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{
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return ((Process*) user)->OnLastThreadExit();
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}
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void Process::OnLastThreadExit()
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{
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LastPrayer();
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}
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static void SwitchCurrentAddrspace(addr_t addrspace, void* user)
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{
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((Thread*) user)->SwitchAddressSpace(addrspace);
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}
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void Process::LastPrayer()
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{
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ASSERT(this);
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// This must never be called twice.
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ASSERT(!iszombie);
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// This must be called from a thread using another address space as the
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// address space of this process is about to be destroyed.
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Thread* curthread = CurrentThread();
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ASSERT(curthread->process != this);
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// This can't be called if the process is still alive.
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ASSERT(!firstthread);
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// We need to temporarily reload the correct addrese space of the dying
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// process such that we can unmap and free its memory.
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addr_t prevaddrspace = curthread->SwitchAddressSpace(addrspace);
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ResetAddressSpace();
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descriptors.Reset();
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// Destroy the address space and safely switch to the replacement
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// address space before things get dangerous.
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Memory::DestroyAddressSpace(prevaddrspace,
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SwitchCurrentAddrspace,
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curthread);
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addrspace = 0;
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// Init is nice and will gladly raise our orphaned children and zombies.
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Process* init = Scheduler::GetInitProcess();
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ASSERT(init);
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kthread_mutex_lock(&childlock);
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while ( firstchild )
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{
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ScopedLock firstchildlock(&firstchild->parentlock);
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ScopedLock initlock(&init->childlock);
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Process* process = firstchild;
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firstchild = process->nextsibling;
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process->parent = init;
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process->prevsibling = NULL;
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process->nextsibling = init->firstchild;
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if ( init->firstchild )
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init->firstchild->prevsibling = process;
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init->firstchild = process;
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}
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// Since we have no more children (they are with init now), we don't
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// have to worry about new zombie processes showing up, so just collect
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// those that are left. Then we satisfiy the invariant !zombiechild that
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// applies on process termination.
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bool hadzombies = zombiechild;
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while ( zombiechild )
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{
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ScopedLock zombiechildlock(&zombiechild->parentlock);
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ScopedLock initlock(&init->childlock);
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Process* zombie = zombiechild;
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zombiechild = zombie->nextsibling;
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zombie->prevsibling = NULL;
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zombie->nextsibling = init->zombiechild;
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if ( init->zombiechild )
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init->zombiechild->prevsibling = zombie;
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init->zombiechild = zombie;
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}
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kthread_mutex_unlock(&childlock);
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if ( hadzombies )
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init->NotifyNewZombies();
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iszombie = true;
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bool zombify = !nozombify;
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// This class instance will be destroyed by our parent process when it
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// has received and acknowledged our death.
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kthread_mutex_lock(&parentlock);
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if ( parent )
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parent->NotifyChildExit(this, zombify);
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kthread_mutex_unlock(&parentlock);
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// If nobody is waiting for us, then simply commit suicide.
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if ( !zombify )
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delete this;
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}
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void Process::ResetAddressSpace()
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{
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ASSERT(Memory::GetAddressSpace() == addrspace);
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ProcessSegment* tmp = segments;
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while ( tmp != NULL )
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{
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Memory::UnmapRange(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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void Process::NotifyChildExit(Process* child, bool zombify)
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{
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kthread_mutex_lock(&childlock);
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if ( child->prevsibling )
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child->prevsibling->nextsibling = child->nextsibling;
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if ( child->nextsibling )
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child->nextsibling->prevsibling = child->prevsibling;
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if ( firstchild == child )
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firstchild = child->nextsibling;
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if ( firstchild )
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firstchild->prevsibling = NULL;
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if ( zombify )
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{
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if ( zombiechild )
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zombiechild->prevsibling = child;
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child->prevsibling = NULL;
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child->nextsibling = zombiechild;
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zombiechild = child;
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}
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kthread_mutex_unlock(&childlock);
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if ( zombify )
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NotifyNewZombies();
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}
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void Process::NotifyNewZombies()
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{
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ScopedLock lock(&childlock);
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// TODO: Send SIGCHLD here?
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if ( zombiewaiting )
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kthread_cond_broadcast(&zombiecond);
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}
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pid_t Process::Wait(pid_t thepid, int* status, int options)
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{
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// TODO: Process groups are not supported yet.
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if ( thepid < -1 || thepid == 0 ) { Error::Set(ENOSYS); return -1; }
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ScopedLock lock(&childlock);
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// A process can only wait if it has children.
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if ( !firstchild && !zombiechild ) { Error::Set(ECHILD); return -1; }
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// Processes can only wait for their own children to exit.
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if ( 0 < thepid )
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{
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// TODO: This is a slow but multithread safe way to verify that the
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// target process has the correct parent.
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bool found = false;
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for ( Process* p = firstchild; !found && p; p = p->nextsibling )
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if ( p->pid == thepid )
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found = true;
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for ( Process* p = zombiechild; !found && p; p = p->nextsibling )
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if ( p->pid == thepid )
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found = true;
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if ( !found ) { Error::Set(ECHILD); return -1; }
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}
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Process* zombie = NULL;
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while ( !zombie )
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{
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for ( zombie = zombiechild; zombie; zombie = zombie->nextsibling )
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if ( thepid == -1 || thepid == zombie->pid )
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break;
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if ( zombie )
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break;
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zombiewaiting++;
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kthread_cond_wait(&zombiecond, &childlock);
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zombiewaiting--;
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}
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if ( zombie->prevsibling )
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zombie->prevsibling->nextsibling = zombie->nextsibling;
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if ( zombie->nextsibling )
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zombie->nextsibling->prevsibling = zombie->prevsibling;
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if ( zombiechild == zombie )
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zombiechild = zombie->nextsibling;
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if ( zombiechild )
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zombiechild->prevsibling = NULL;
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thepid = zombie->pid;
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int exitstatus = zombie->exitstatus;
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if ( exitstatus < 0 )
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exitstatus = 0;
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// TODO: Validate that status is a valid user-space int!
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if ( status )
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*status = exitstatus;
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// And so, the process was fully deleted.
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delete zombie;
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return thepid;
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}
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pid_t SysWait(pid_t pid, int* status, int options)
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{
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return CurrentProcess()->Wait(pid, status, options);
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}
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void Process::Exit(int status)
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{
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ScopedLock lock(&threadlock);
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// Status codes can only contain 8 bits according to ISO C and POSIX.
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if ( exitstatus == -1 )
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exitstatus = status % 256;
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// Broadcast SIGKILL to all our threads which will begin our long path
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// of process termination. We simply can't stop the threads as they may
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// be running in kernel mode doing dangerous stuff. This thread will be
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// destroyed by SIGKILL once the system call returns.
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for ( Thread* t = firstthread; t; t = t->nextsibling )
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t->DeliverSignal(SIGKILL);
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}
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void SysExit(int status)
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{
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CurrentProcess()->Exit(status);
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}
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bool Process::DeliverSignal(int signum)
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{
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// TODO: How to handle signals that kill the process?
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if ( firstthread )
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return firstthread->DeliverSignal(signum);
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Error::Set(EINIT);
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return false;
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}
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void Process::AddChildProcess(Process* child)
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{
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ScopedLock mylock(&childlock);
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ScopedLock itslock(&child->parentlock);
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ASSERT(!child->parent);
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ASSERT(!child->nextsibling);
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ASSERT(!child->prevsibling);
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child->parent = this;
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child->nextsibling = firstchild;
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child->prevsibling = NULL;
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if ( firstchild )
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firstchild->prevsibling = child;
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firstchild = child;
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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.
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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, we simply
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// ask the process to commit suicide before it goes live.
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clone->segments = clonesegments;
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// Remember the relation to the child process.
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AddChildProcess(clone);
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bool failure = false;
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if ( !descriptors.Fork(&clone->descriptors) )
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failure = true;
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clone->mmapfrom = mmapfrom;
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clone->workingdir = NULL;
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if ( workingdir && !(clone->workingdir = String::Clone(workingdir)) )
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failure = true;
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// If the proces creation failed, ask the process to commit suicide and
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// not become a zombie, as we don't wait for it to exit. It will clean
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// up all the above resources and delete itself.
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if ( failure )
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{
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clone->AbortConstruction();
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return NULL;
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}
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return clone;
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}
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void Process::ResetForExecute()
|
|
{
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// TODO: Delete all threads and their stacks.
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|
|
|
ResetAddressSpace();
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}
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|
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int Process::Execute(const char* programname, const byte* program,
|
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size_t programsize, int argc, const char* const* argv,
|
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int envc, const char* const* envp,
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|
CPU::InterruptRegisters* regs)
|
|
{
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|
ASSERT(CurrentProcess() == this);
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|
addr_t entry = ELF::Construct(CurrentProcess(), program, programsize);
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if ( !entry ) { return -1; }
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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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|
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addr_t stackpos = CurrentThread()->stackpos + CurrentThread()->stacksize;
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// Alright, move argv onto the new stack! First figure out exactly how
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// big argv actually is.
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addr_t argvpos = stackpos - sizeof(char*) * (argc+1);
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char** stackargv = (char**) argvpos;
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|
|
|
size_t argvsize = 0;
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for ( int i = 0; i < argc; i++ )
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|
{
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|
size_t len = String::Length(argv[i]) + 1;
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argvsize += len;
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char* dest = ((char*) argvpos) - argvsize;
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stackargv[i] = dest;
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Maxsi::Memory::Copy(dest, argv[i], len);
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}
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stackargv[argc] = NULL;
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if ( argvsize % 16UL ) { argvsize += 16 - (argvsize % 16UL); }
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// And then move envp onto the stack.
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addr_t envppos = argvpos - argvsize - sizeof(char*) * (envc+1);
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char** stackenvp = (char**) envppos;
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|
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size_t envpsize = 0;
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for ( int i = 0; i < envc; i++ )
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|
{
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size_t len = String::Length(envp[i]) + 1;
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envpsize += len;
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char* dest = ((char*) envppos) - envpsize;
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stackenvp[i] = dest;
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Maxsi::Memory::Copy(dest, envp[i], len);
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}
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stackenvp[envc] = NULL;
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if ( envpsize % 16UL ) { envpsize += 16 - (envpsize % 16UL); }
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stackpos = envppos - envpsize;
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descriptors.OnExecute();
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ExecuteCPU(argc, stackargv, envc, stackenvp, stackpos, entry, regs);
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return 0;
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}
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DevBuffer* OpenProgramImage(const char* progname, const char* wd, const char* path)
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|
{
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char* abs = Directory::MakeAbsolute("/", progname);
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if ( !abs ) { Error::Set(ENOMEM); return NULL; }
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// TODO: Use O_EXEC here!
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Device* dev = FileSystem::Open(abs, O_RDONLY, 0);
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delete[] abs;
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if ( !dev ) { return NULL; }
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if ( !dev->IsType(Device::BUFFER) ) { Error::Set(EACCES); dev->Unref(); return NULL; }
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return (DevBuffer*) dev;
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}
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int SysExecVE(const char* _filename, char* const _argv[], char* const _envp[])
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{
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char* filename;
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int argc;
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int envc;
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char** argv;
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char** envp;
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DevBuffer* dev;
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uintmax_t needed;
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size_t sofar;
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size_t count;
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uint8_t* buffer;
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int result = -1;
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Process* process = CurrentProcess();
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CPU::InterruptRegisters regs;
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Maxsi::Memory::Set(®s, 0, sizeof(regs));
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filename = String::Clone(_filename);
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if ( !filename ) { goto cleanup_done; }
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for ( argc = 0; _argv && _argv[argc]; argc++ );
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for ( envc = 0; _envp && _envp[envc]; envc++ );
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argv = new char*[argc+1];
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if ( !argv ) { goto cleanup_filename; }
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Maxsi::Memory::Set(argv, 0, sizeof(char*) * (argc+1));
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|
|
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for ( int i = 0; i < argc; i++ )
|
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{
|
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argv[i] = String::Clone(_argv[i]);
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if ( !argv[i] ) { goto cleanup_argv; }
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}
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|
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envp = new char*[envc+1];
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if ( !envp ) { goto cleanup_argv; }
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envc = envc;
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Maxsi::Memory::Set(envp, 0, sizeof(char*) * (envc+1));
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|
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for ( int i = 0; i < envc; i++ )
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{
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envp[i] = String::Clone(_envp[i]);
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if ( !envp[i] ) { goto cleanup_envp; }
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}
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|
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dev = OpenProgramImage(filename, process->workingdir, "/bin");
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if ( !dev ) { goto cleanup_envp; }
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dev->Refer(); // TODO: Rules of GC may change soon.
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needed = dev->Size();
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if ( SIZE_MAX < needed ) { Error::Set(ENOMEM); goto cleanup_dev; }
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if ( !dev->IsReadable() ) { Error::Set(EBADF); goto cleanup_dev; }
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count = needed;
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buffer = new byte[count];
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if ( !buffer ) { goto cleanup_dev; }
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sofar = 0;
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while ( sofar < count )
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|
{
|
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ssize_t bytesread = dev->Read(buffer + sofar, count - sofar);
|
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if ( bytesread < 0 ) { goto cleanup_buffer; }
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if ( bytesread == 0 ) { Error::Set(EEOF); return -1; }
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sofar += bytesread;
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}
|
|
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|
result = process->Execute(filename, buffer, count, argc, argv, envc,
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envp, ®s);
|
|
|
|
cleanup_buffer:
|
|
delete[] buffer;
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|
cleanup_dev:
|
|
dev->Unref();
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|
cleanup_envp:
|
|
for ( int i = 0; i < envc; i++) { delete[] envp[i]; }
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|
delete[] envp;
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|
cleanup_argv:
|
|
for ( int i = 0; i < argc; i++) { delete[] argv[i]; }
|
|
delete[] argv;
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cleanup_filename:
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|
delete[] filename;
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cleanup_done:
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if ( !result ) { CPU::LoadRegisters(®s); }
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return result;
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}
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pid_t SysSForkR(int flags, sforkregs_t* regs)
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|
{
|
|
if ( Signal::IsPending() ) { Error::Set(EINTR); return -1; }
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|
// TODO: Properly support sforkr(2).
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if ( flags != SFFORK ) { Error::Set(ENOSYS); return -1; }
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|
|
CPU::InterruptRegisters cpuregs;
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|
InitializeThreadRegisters(&cpuregs, regs);
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|
|
|
// TODO: Is it a hack to create a new kernel stack here?
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|
Thread* curthread = CurrentThread();
|
|
uint8_t* newkernelstack = new uint8_t[curthread->kernelstacksize];
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|
if ( !newkernelstack ) { return -1; }
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|
Process* clone = CurrentProcess()->Fork();
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if ( !clone ) { delete[] newkernelstack; return -1; }
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|
|
// If the thread could not be created, make the process commit suicide
|
|
// in a manner such that we don't wait for its zombie.
|
|
Thread* thread = CreateKernelThread(clone, &cpuregs);
|
|
if ( !thread )
|
|
{
|
|
clone->AbortConstruction();
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|
return -1;
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|
}
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|
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|
thread->kernelstackpos = (addr_t) newkernelstack;
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|
thread->kernelstacksize = curthread->kernelstacksize;
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|
thread->kernelstackmalloced = true;
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|
thread->stackpos = curthread->stackpos;
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|
thread->stacksize = curthread->stacksize;
|
|
thread->sighandler = curthread->sighandler;
|
|
|
|
StartKernelThread(thread);
|
|
|
|
return clone->pid;
|
|
}
|
|
|
|
pid_t SysGetPID()
|
|
{
|
|
return CurrentProcess()->pid;
|
|
}
|
|
|
|
pid_t Process::GetParentProcessId()
|
|
{
|
|
ScopedLock lock(&parentlock);
|
|
if( !parent )
|
|
return 0;
|
|
return parent->pid;
|
|
}
|
|
|
|
pid_t SysGetParentPID()
|
|
{
|
|
return CurrentProcess()->GetParentProcessId();
|
|
}
|
|
|
|
pid_t nextpidtoallocate;
|
|
kthread_mutex_t pidalloclock;
|
|
|
|
pid_t Process::AllocatePID()
|
|
{
|
|
ScopedLock lock(&pidalloclock);
|
|
return nextpidtoallocate++;
|
|
}
|
|
|
|
// TODO: This is not thread safe.
|
|
pid_t Process::HackGetForegroundProcess()
|
|
{
|
|
for ( pid_t i = nextpidtoallocate; 1 <= i; i-- )
|
|
{
|
|
Process* process = Get(i);
|
|
if ( !process )
|
|
continue;
|
|
if ( process->pid <= 1 )
|
|
continue;
|
|
return i;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
int ProcessCompare(Process* a, Process* b)
|
|
{
|
|
if ( a->pid < b->pid ) { return -1; }
|
|
if ( a->pid > b->pid ) { return 1; }
|
|
return 0;
|
|
}
|
|
|
|
int ProcessPIDCompare(Process* a, pid_t pid)
|
|
{
|
|
if ( a->pid < pid ) { return -1; }
|
|
if ( a->pid > pid ) { return 1; }
|
|
return 0;
|
|
}
|
|
|
|
SortedList<Process*>* pidlist;
|
|
|
|
Process* Process::Get(pid_t pid)
|
|
{
|
|
ScopedLock lock(&pidalloclock);
|
|
size_t index = pidlist->Search(ProcessPIDCompare, pid);
|
|
if ( index == SIZE_MAX ) { return NULL; }
|
|
|
|
return pidlist->Get(index);
|
|
}
|
|
|
|
bool Process::Put(Process* process)
|
|
{
|
|
ScopedLock lock(&pidalloclock);
|
|
return pidlist->Add(process);
|
|
}
|
|
|
|
void Process::Remove(Process* process)
|
|
{
|
|
ScopedLock lock(&pidalloclock);
|
|
size_t index = pidlist->Search(process);
|
|
ASSERT(index != SIZE_MAX);
|
|
|
|
pidlist->Remove(index);
|
|
}
|
|
|
|
void* SysSbrk(intptr_t increment)
|
|
{
|
|
Process* process = CurrentProcess();
|
|
ProcessSegment* dataseg = NULL;
|
|
for ( ProcessSegment* iter = process->segments; iter; iter = iter->next )
|
|
{
|
|
if ( !iter->type == SEG_DATA ) { continue; }
|
|
if ( dataseg && iter->position < dataseg->position ) { continue; }
|
|
dataseg = iter;
|
|
}
|
|
if ( !dataseg ) { Error::Set(ENOMEM); return (void*) -1UL; }
|
|
addr_t currentend = dataseg->position + dataseg->size;
|
|
addr_t newend = currentend + increment;
|
|
if ( newend < dataseg->position ) { Error::Set(EINVAL); return (void*) -1UL; }
|
|
if ( newend < currentend )
|
|
{
|
|
addr_t unmapfrom = Page::AlignUp(newend);
|
|
if ( unmapfrom < currentend )
|
|
{
|
|
size_t unmapbytes = Page::AlignUp(currentend - unmapfrom);
|
|
Memory::UnmapRange(unmapfrom, unmapbytes);
|
|
}
|
|
}
|
|
else if ( currentend < newend )
|
|
{
|
|
// TODO: HACK: Make a safer way of expanding the data segment
|
|
// without segments possibly colliding!
|
|
addr_t mapfrom = Page::AlignUp(currentend);
|
|
if ( mapfrom < newend )
|
|
{
|
|
size_t mapbytes = Page::AlignUp(newend - mapfrom);
|
|
int prot = PROT_FORK | PROT_READ | PROT_WRITE | PROT_KREAD | PROT_KWRITE;
|
|
if ( !Memory::MapRange(mapfrom, mapbytes, prot) )
|
|
{
|
|
return (void*) -1UL;
|
|
}
|
|
}
|
|
}
|
|
dataseg->size += increment;
|
|
return (void*) newend;
|
|
}
|
|
|
|
size_t SysGetPageSize()
|
|
{
|
|
return Page::Size();
|
|
}
|
|
|
|
void Process::Init()
|
|
{
|
|
Syscall::Register(SYSCALL_EXEC, (void*) SysExecVE);
|
|
Syscall::Register(SYSCALL_SFORKR, (void*) SysSForkR);
|
|
Syscall::Register(SYSCALL_GETPID, (void*) SysGetPID);
|
|
Syscall::Register(SYSCALL_GETPPID, (void*) SysGetParentPID);
|
|
Syscall::Register(SYSCALL_EXIT, (void*) SysExit);
|
|
Syscall::Register(SYSCALL_WAIT, (void*) SysWait);
|
|
Syscall::Register(SYSCALL_SBRK, (void*) SysSbrk);
|
|
Syscall::Register(SYSCALL_GET_PAGE_SIZE, (void*) SysGetPageSize);
|
|
|
|
pidalloclock = KTHREAD_MUTEX_INITIALIZER;
|
|
nextpidtoallocate = 0;
|
|
|
|
pidlist = new SortedList<Process*>(ProcessCompare);
|
|
if ( !pidlist ) { Panic("could not allocate pidlist\n"); }
|
|
}
|
|
|
|
addr_t Process::AllocVirtualAddr(size_t size)
|
|
{
|
|
return (mmapfrom -= size);
|
|
}
|
|
}
|