Method copyProcess

lab8/src/4/src/kernel/program.cpp:379–511

}

bool ProgramManager::copyProcess(PCB *parent, PCB *child)
{
    // 复制进程0级栈
    ProcessStartStack *childpss =
        (ProcessStartStack *)((int)child + PAGE_SIZE - sizeof(ProcessStartStack));
    ProcessStartStack *parentpss =
        (ProcessStartStack *)((int)parent + PAGE_SIZE - sizeof(ProcessStartStack));
    memcpy(parentpss, childpss, sizeof(ProcessStartStack));
    // 设置子进程的返回值为0
    childpss->eax = 0;

    // 准备执行asm_switch_thread的栈的内容
    child->stack = (int *)childpss - 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)childpss; // asm_start_process 参数

    // 设置子进程的PCB
    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);

    // 从内核中分配一页作为中转页
    char *buffer = (char *)memoryManager.allocatePages(AddressPoolType::KERNEL, 1);
    if (!buffer)
    {
        child->status = ProgramStatus::DEAD;
        return false;
    }

    // 子进程页目录表物理地址
    int childPageDirPaddr = memoryManager.vaddr2paddr(child->pageDirectoryAddress);
    // 父进程页目录表物理地址
    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;

    // 子进程页目录表初始化
    memset((void *)child->pageDirectoryAddress, 0, 768 * 4);

    // 复制页目录表
    for (int i = 0; i < 768; ++i)
    {
        // 无对应页表