mirror of
https://github.com/RGBCube/serenity
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f1b5def8fd
This patch adds Space, a class representing a process's address space. - Each Process has a Space. - The Space owns the PageDirectory and all Regions in the Process. This allows us to reorganize sys$execve() so that it constructs and populates a new Space fully before committing to it. Previously, we would construct the new address space while still running in the old one, and encountering an error meant we had to do tedious and error-prone rollback. Those problems are now gone, replaced by what's hopefully a set of much smaller problems and missing cleanups. :^)
107 lines
3.8 KiB
C++
107 lines
3.8 KiB
C++
/*
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* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/ScopeGuard.h>
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#include <Kernel/Process.h>
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#include <Kernel/Ptrace.h>
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#include <Kernel/VM/MemoryManager.h>
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#include <Kernel/VM/PrivateInodeVMObject.h>
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#include <Kernel/VM/ProcessPagingScope.h>
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#include <Kernel/VM/Region.h>
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#include <Kernel/VM/SharedInodeVMObject.h>
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namespace Kernel {
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int Process::sys$ptrace(Userspace<const Syscall::SC_ptrace_params*> user_params)
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{
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REQUIRE_PROMISE(ptrace);
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Syscall::SC_ptrace_params params;
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if (!copy_from_user(¶ms, user_params))
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return -EFAULT;
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auto result = Ptrace::handle_syscall(params, *this);
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return result.is_error() ? result.error().error() : result.value();
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}
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/**
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* "Does this process have a thread that is currently being traced by the provided process?"
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*/
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bool Process::has_tracee_thread(ProcessID tracer_pid)
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{
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if (auto tracer = this->tracer())
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return tracer->tracer_pid() == tracer_pid;
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return false;
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}
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KResultOr<u32> Process::peek_user_data(Userspace<const u32*> address)
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{
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uint32_t result;
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// This function can be called from the context of another
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// process that called PT_PEEK
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ProcessPagingScope scope(*this);
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if (!copy_from_user(&result, address)) {
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dbgln("Invalid address for peek_user_data: {}", address.ptr());
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return EFAULT;
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}
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return result;
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}
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KResult Process::poke_user_data(Userspace<u32*> address, u32 data)
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{
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Range range = { VirtualAddress(address), sizeof(u32) };
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auto* region = space().find_region_containing(range);
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if (!region)
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return EFAULT;
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ProcessPagingScope scope(*this);
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if (region->is_shared()) {
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// If the region is shared, we change its vmobject to a PrivateInodeVMObject
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// to prevent the write operation from changing any shared inode data
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ASSERT(region->vmobject().is_shared_inode());
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region->set_vmobject(PrivateInodeVMObject::create_with_inode(static_cast<SharedInodeVMObject&>(region->vmobject()).inode()));
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region->set_shared(false);
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}
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const bool was_writable = region->is_writable();
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if (!was_writable) {
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region->set_writable(true);
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region->remap();
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}
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ScopeGuard rollback([&]() {
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if (!was_writable) {
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region->set_writable(false);
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region->remap();
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}
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});
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if (!copy_to_user(address, &data)) {
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dbgln("poke_user_data: Bad address {:p}", address.ptr());
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return EFAULT;
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}
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return KSuccess;
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}
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}
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