citra/src/core/hle/kernel/ipc.cpp

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// Copyright 2017 Citra Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.
#include "common/alignment.h"
#include "core/hle/ipc.h"
#include "core/hle/kernel/handle_table.h"
#include "core/hle/kernel/ipc.h"
#include "core/hle/kernel/kernel.h"
#include "core/hle/kernel/memory.h"
#include "core/hle/kernel/process.h"
#include "core/hle/kernel/thread.h"
#include "core/memory.h"
namespace Kernel {
ResultCode TranslateCommandBuffer(SharedPtr<Thread> src_thread, SharedPtr<Thread> dst_thread,
VAddr src_address, VAddr dst_address, bool reply) {
auto& src_process = src_thread->owner_process;
auto& dst_process = dst_thread->owner_process;
IPC::Header header;
// TODO(Subv): Replace by Memory::Read32 when possible.
Memory::ReadBlock(*src_process, src_address, &header.raw, sizeof(header.raw));
std::size_t untranslated_size = 1u + header.normal_params_size;
std::size_t command_size = untranslated_size + header.translate_params_size;
// Note: The real kernel does not check that the command length fits into the IPC buffer area.
ASSERT(command_size <= IPC::COMMAND_BUFFER_LENGTH);
std::array<u32, IPC::COMMAND_BUFFER_LENGTH> cmd_buf;
Memory::ReadBlock(*src_process, src_address, cmd_buf.data(), command_size * sizeof(u32));
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// Create a copy of the target's command buffer
IPC::Header dst_header;
Memory::ReadBlock(*dst_process, dst_address, &dst_header.raw, sizeof(dst_header.raw));
std::size_t dst_untranslated_size = 1u + dst_header.normal_params_size;
std::size_t dst_command_size = dst_untranslated_size + dst_header.translate_params_size;
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std::size_t target_index = dst_untranslated_size;
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std::array<u32, IPC::COMMAND_BUFFER_LENGTH> dst_cmd_buf;
Memory::ReadBlock(*dst_process, dst_address, dst_cmd_buf.data(),
dst_command_size * sizeof(u32));
std::size_t i = untranslated_size;
while (i < command_size) {
u32 descriptor = cmd_buf[i];
i += 1;
switch (IPC::GetDescriptorType(descriptor)) {
case IPC::DescriptorType::CopyHandle:
case IPC::DescriptorType::MoveHandle: {
u32 num_handles = IPC::HandleNumberFromDesc(descriptor);
// Note: The real kernel does not check that the number of handles fits into the command
// buffer before writing them, only after finishing.
if (i + num_handles > command_size) {
return ResultCode(ErrCodes::CommandTooLarge, ErrorModule::OS,
ErrorSummary::InvalidState, ErrorLevel::Status);
}
for (u32 j = 0; j < num_handles; ++j) {
Handle handle = cmd_buf[i];
SharedPtr<Object> object = nullptr;
// Perform pseudo-handle detection here because by the time this function is called,
// the current thread and process are no longer the ones which created this IPC
// request, but the ones that are handling it.
if (handle == CurrentThread) {
object = src_thread;
} else if (handle == CurrentProcess) {
object = src_process;
} else if (handle != 0) {
object = g_handle_table.GetGeneric(handle);
if (descriptor == IPC::DescriptorType::MoveHandle) {
g_handle_table.Close(handle);
}
}
if (object == nullptr) {
// Note: The real kernel sets invalid translated handles to 0 in the target
// command buffer.
cmd_buf[i++] = 0;
continue;
}
auto result = g_handle_table.Create(std::move(object));
cmd_buf[i++] = result.ValueOr(0);
}
break;
}
case IPC::DescriptorType::CallingPid: {
cmd_buf[i++] = src_process->process_id;
break;
}
case IPC::DescriptorType::StaticBuffer: {
IPC::StaticBufferDescInfo bufferInfo{descriptor};
VAddr static_buffer_src_address = cmd_buf[i];
std::vector<u8> data(bufferInfo.size);
Memory::ReadBlock(*src_process, static_buffer_src_address, data.data(), data.size());
// Grab the address that the target thread set up to receive the response static buffer
// and write our data there. The static buffers area is located right after the command
// buffer area.
struct StaticBuffer {
IPC::StaticBufferDescInfo descriptor;
VAddr address;
};
static_assert(sizeof(StaticBuffer) == 8, "StaticBuffer struct has incorrect size.");
StaticBuffer target_buffer;
u32 static_buffer_offset = IPC::COMMAND_BUFFER_LENGTH * sizeof(u32) +
sizeof(StaticBuffer) * bufferInfo.buffer_id;
Memory::ReadBlock(*dst_process, dst_address + static_buffer_offset, &target_buffer,
sizeof(target_buffer));
// Note: The real kernel doesn't seem to have any error recovery mechanisms for this
// case.
ASSERT_MSG(target_buffer.descriptor.size >= data.size(),
"Static buffer data is too big");
Memory::WriteBlock(*dst_process, target_buffer.address, data.data(), data.size());
cmd_buf[i++] = target_buffer.address;
break;
}
case IPC::DescriptorType::MappedBuffer: {
IPC::MappedBufferDescInfo descInfo{descriptor};
VAddr source_address = cmd_buf[i];
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u32 size = static_cast<u32>(descInfo.size);
IPC::MappedBufferPermissions permissions = descInfo.perms;
VAddr page_start = Common::AlignDown(source_address, Memory::PAGE_SIZE);
u32 page_offset = source_address - page_start;
u32 num_pages =
Common::AlignUp(page_offset + size, Memory::PAGE_SIZE) >> Memory::PAGE_BITS;
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// Skip when the size is zero and num_pages == 0
if (size == 0) {
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cmd_buf[i++] = 0;
break;
}
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ASSERT(num_pages >= 1);
if (reply) {
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// Scan the target's command buffer for the matching mapped buffer
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while (target_index < dst_command_size) {
u32 desc = dst_cmd_buf[target_index++];
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if (IPC::GetDescriptorType(desc) == IPC::DescriptorType::MappedBuffer) {
IPC::MappedBufferDescInfo dest_descInfo{desc};
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VAddr dest_address = dst_cmd_buf[target_index];
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u32 dest_size = static_cast<u32>(dest_descInfo.size);
IPC::MappedBufferPermissions dest_permissions = dest_descInfo.perms;
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ASSERT(permissions == dest_permissions && size == dest_size);
// Readonly buffers do not need to be copied over to the target
// process again because they were (presumably) not modified. This
// behavior is consistent with the real kernel.
if (permissions != IPC::MappedBufferPermissions::R) {
// Copy the modified buffer back into the target process
Memory::CopyBlock(*src_process, *dst_process, source_address,
dest_address, size);
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}
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VAddr prev_reserve = page_start - Memory::PAGE_SIZE;
VAddr next_reserve = page_start + num_pages * Memory::PAGE_SIZE;
auto& prev_vma = src_process->vm_manager.FindVMA(prev_reserve)->second;
auto& next_vma = src_process->vm_manager.FindVMA(next_reserve)->second;
ASSERT(prev_vma.meminfo_state == MemoryState::Reserved &&
next_vma.meminfo_state == MemoryState::Reserved);
// Unmap the buffer and guard pages from the source process
ResultCode result = src_process->vm_manager.UnmapRange(
page_start - Memory::PAGE_SIZE, (num_pages + 2) * Memory::PAGE_SIZE);
ASSERT(result == RESULT_SUCCESS);
target_index += 1;
break;
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}
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target_index += 1;
}
i += 1;
break;
}
VAddr target_address = 0;
// TODO(Subv): Perform permission checks.
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// Reserve a page of memory before the mapped buffer
auto reserve_buffer = std::make_shared<std::vector<u8>>(Memory::PAGE_SIZE);
dst_process->vm_manager.MapMemoryBlockToBase(
Memory::IPC_MAPPING_VADDR, Memory::IPC_MAPPING_SIZE, reserve_buffer, 0,
static_cast<u32>(reserve_buffer->size()), Kernel::MemoryState::Reserved);
auto buffer = std::make_shared<std::vector<u8>>(num_pages * Memory::PAGE_SIZE);
Memory::ReadBlock(*src_process, source_address, buffer->data() + page_offset, size);
// Map the page(s) into the target process' address space.
target_address = dst_process->vm_manager
.MapMemoryBlockToBase(
Memory::IPC_MAPPING_VADDR, Memory::IPC_MAPPING_SIZE, buffer, 0,
static_cast<u32>(buffer->size()), Kernel::MemoryState::Shared)
.Unwrap();
cmd_buf[i++] = target_address + page_offset;
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// Reserve a page of memory after the mapped buffer
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dst_process->vm_manager.MapMemoryBlockToBase(
Memory::IPC_MAPPING_VADDR, Memory::IPC_MAPPING_SIZE, reserve_buffer, 0,
static_cast<u32>(reserve_buffer->size()), Kernel::MemoryState::Reserved);
break;
}
default:
UNIMPLEMENTED_MSG("Unsupported handle translation: {:#010X}", descriptor);
}
}
Memory::WriteBlock(*dst_process, dst_address, cmd_buf.data(), command_size * sizeof(u32));
return RESULT_SUCCESS;
}
} // namespace Kernel