Method copyProcess

lab8/src/7/src/kernel/program.cpp:388–511

}

bool ProgramManager::copyProcess(PCB *parent, PCB *child)
{
    // 复制PCB
    ProcessStartStack *childpps = (ProcessStartStack *)((int)child + PAGE_SIZE - sizeof(ProcessStartStack));
    ProcessStartStack *parentpps = (ProcessStartStack *)((int)parent + PAGE_SIZE - sizeof(ProcessStartStack));
    memcpy(parentpps, childpps, sizeof(ProcessStartStack));
    childpps->eax = 0;

    child->stack = (int *)childpps - 7;
    child->stack[0] = 0;
    child->stack[1] = 0;
    child->stack[2] = 0;
    child->stack[3] = 0;
    child->stack[4] = (int)asm_start_process;
    child->stack[5] = 0;             // asm_start_process 返回地址
    child->stack[6] = (int)childpps; // asm_start_process 参数

    child->status = ProgramStatus::READY;
    child->parentPid = parent->pid;
    child->priority = parent->priority;
    child->ticks = parent->ticks;
    child->ticksPassedBy = parent->ticksPassedBy;
    strcpy(parent->name, child->name);

    // 复制用户虚拟地址池
    int bitmapLength = parent->userVirtual.resources.length;
    int bitmapBytes = ceil(bitmapLength, 8);
    memcpy(parent->userVirtual.resources.bitmap, child->userVirtual.resources.bitmap, bitmapBytes);

    char *buffer = (char *)memoryManager.allocatePages(AddressPoolType::KERNEL, 1);
    if (!buffer)
    {
        child->status = ProgramStatus::DEAD;
        return false;
    }

    // 子进程页目录表地址
    int childPageDirPaddr = memoryManager.vaddr2paddr(child->pageDirectoryAddress);
    // 父进程页目录表地址
    int parentPageDirPaddr = memoryManager.vaddr2paddr(parent->pageDirectoryAddress);
    // 子进程页目录表指针(虚拟地址)
    int *childPageDir = (int *)child->pageDirectoryAddress;
    // 父进程页目录表指针(虚拟地址)
    int *parentPageDir = (int *)parent->pageDirectoryAddress;

    //printf("%x %x\n", parent->pageDirectoryAddress, child->pageDirectoryAddress);

    memset((void *)child->pageDirectoryAddress, 0, 768 * 4);

    for (int i = 0; i < 768; ++i)
    {
        // 无对应页表
        if (!(parentPageDir[i] & 0x1))
        {
            continue;
        }

        // 从用户物理地址池中分配一页，作为子进程的页目录项指向的页表