xref: /DragonOS/kernel/src/process/mod.rs (revision 9a0802fd2ddda39e96342997abbfc30bf65f1f0e)
1 use core::{
2     hash::Hash,
3     hint::spin_loop,
4     intrinsics::{likely, unlikely},
5     mem::ManuallyDrop,
6     sync::atomic::{compiler_fence, fence, AtomicBool, AtomicUsize, Ordering},
7 };
8 
9 use alloc::{
10     string::{String, ToString},
11     sync::{Arc, Weak},
12     vec::Vec,
13 };
14 use hashbrown::HashMap;
15 use system_error::SystemError;
16 
17 use crate::{
18     arch::{
19         cpu::current_cpu_id,
20         ipc::signal::{AtomicSignal, SigSet, Signal},
21         process::ArchPCBInfo,
22         CurrentIrqArch,
23     },
24     driver::tty::tty_core::TtyCore,
25     exception::InterruptArch,
26     filesystem::{
27         procfs::procfs_unregister_pid,
28         vfs::{file::FileDescriptorVec, FileType},
29     },
30     ipc::signal_types::{SigInfo, SigPending, SignalStruct},
31     kdebug, kinfo,
32     libs::{
33         align::AlignedBox,
34         casting::DowncastArc,
35         futex::{
36             constant::{FutexFlag, FUTEX_BITSET_MATCH_ANY},
37             futex::{Futex, RobustListHead},
38         },
39         lock_free_flags::LockFreeFlags,
40         rwlock::{RwLock, RwLockReadGuard, RwLockWriteGuard},
41         spinlock::{SpinLock, SpinLockGuard},
42         wait_queue::WaitQueue,
43     },
44     mm::{
45         percpu::{PerCpu, PerCpuVar},
46         set_IDLE_PROCESS_ADDRESS_SPACE,
47         ucontext::AddressSpace,
48         VirtAddr,
49     },
50     net::socket::SocketInode,
51     sched::completion::Completion,
52     sched::{
53         cpu_rq, fair::FairSchedEntity, prio::MAX_PRIO, DequeueFlag, EnqueueFlag, OnRq, SchedMode,
54         WakeupFlags, __schedule,
55     },
56     smp::{
57         core::smp_get_processor_id,
58         cpu::{AtomicProcessorId, ProcessorId},
59         kick_cpu,
60     },
61     syscall::{user_access::clear_user, Syscall},
62 };
63 use timer::AlarmTimer;
64 
65 use self::kthread::WorkerPrivate;
66 
67 pub mod abi;
68 pub mod c_adapter;
69 pub mod exec;
70 pub mod exit;
71 pub mod fork;
72 pub mod idle;
73 pub mod kthread;
74 pub mod pid;
75 pub mod resource;
76 pub mod stdio;
77 pub mod syscall;
78 pub mod timer;
79 pub mod utils;
80 
81 /// 系统中所有进程的pcb
82 static ALL_PROCESS: SpinLock<Option<HashMap<Pid, Arc<ProcessControlBlock>>>> = SpinLock::new(None);
83 
84 pub static mut PROCESS_SWITCH_RESULT: Option<PerCpuVar<SwitchResult>> = None;
85 
86 /// 一个只改变1次的全局变量,标志进程管理器是否已经初始化完成
87 static mut __PROCESS_MANAGEMENT_INIT_DONE: bool = false;
88 
89 #[derive(Debug)]
90 pub struct SwitchResult {
91     pub prev_pcb: Option<Arc<ProcessControlBlock>>,
92     pub next_pcb: Option<Arc<ProcessControlBlock>>,
93 }
94 
95 impl SwitchResult {
96     pub fn new() -> Self {
97         Self {
98             prev_pcb: None,
99             next_pcb: None,
100         }
101     }
102 }
103 
104 #[derive(Debug)]
105 pub struct ProcessManager;
106 impl ProcessManager {
107     #[inline(never)]
108     fn init() {
109         static INIT_FLAG: AtomicBool = AtomicBool::new(false);
110         if INIT_FLAG
111             .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst)
112             .is_err()
113         {
114             panic!("ProcessManager has been initialized!");
115         }
116 
117         unsafe {
118             compiler_fence(Ordering::SeqCst);
119             kdebug!("To create address space for INIT process.");
120             // test_buddy();
121             set_IDLE_PROCESS_ADDRESS_SPACE(
122                 AddressSpace::new(true).expect("Failed to create address space for INIT process."),
123             );
124             kdebug!("INIT process address space created.");
125             compiler_fence(Ordering::SeqCst);
126         };
127 
128         ALL_PROCESS.lock_irqsave().replace(HashMap::new());
129         Self::init_switch_result();
130         Self::arch_init();
131         kdebug!("process arch init done.");
132         Self::init_idle();
133         kdebug!("process idle init done.");
134 
135         unsafe { __PROCESS_MANAGEMENT_INIT_DONE = true };
136         kinfo!("Process Manager initialized.");
137     }
138 
139     fn init_switch_result() {
140         let mut switch_res_vec: Vec<SwitchResult> = Vec::new();
141         for _ in 0..PerCpu::MAX_CPU_NUM {
142             switch_res_vec.push(SwitchResult::new());
143         }
144         unsafe {
145             PROCESS_SWITCH_RESULT = Some(PerCpuVar::new(switch_res_vec).unwrap());
146         }
147     }
148 
149     /// 判断进程管理器是否已经初始化完成
150     #[allow(dead_code)]
151     pub fn initialized() -> bool {
152         unsafe { __PROCESS_MANAGEMENT_INIT_DONE }
153     }
154 
155     /// 获取当前进程的pcb
156     pub fn current_pcb() -> Arc<ProcessControlBlock> {
157         if unlikely(unsafe { !__PROCESS_MANAGEMENT_INIT_DONE }) {
158             kerror!("unsafe__PROCESS_MANAGEMENT_INIT_DONE == false");
159             loop {
160                 spin_loop();
161             }
162         }
163         return ProcessControlBlock::arch_current_pcb();
164     }
165 
166     /// 获取当前进程的pid
167     ///
168     /// 如果进程管理器未初始化完成,那么返回0
169     pub fn current_pid() -> Pid {
170         if unlikely(unsafe { !__PROCESS_MANAGEMENT_INIT_DONE }) {
171             return Pid(0);
172         }
173 
174         return ProcessManager::current_pcb().pid();
175     }
176 
177     /// 增加当前进程的锁持有计数
178     #[inline(always)]
179     pub fn preempt_disable() {
180         if likely(unsafe { __PROCESS_MANAGEMENT_INIT_DONE }) {
181             ProcessManager::current_pcb().preempt_disable();
182         }
183     }
184 
185     /// 减少当前进程的锁持有计数
186     #[inline(always)]
187     pub fn preempt_enable() {
188         if likely(unsafe { __PROCESS_MANAGEMENT_INIT_DONE }) {
189             ProcessManager::current_pcb().preempt_enable();
190         }
191     }
192 
193     /// 根据pid获取进程的pcb
194     ///
195     /// ## 参数
196     ///
197     /// - `pid` : 进程的pid
198     ///
199     /// ## 返回值
200     ///
201     /// 如果找到了对应的进程,那么返回该进程的pcb,否则返回None
202     pub fn find(pid: Pid) -> Option<Arc<ProcessControlBlock>> {
203         return ALL_PROCESS.lock_irqsave().as_ref()?.get(&pid).cloned();
204     }
205 
206     /// 向系统中添加一个进程的pcb
207     ///
208     /// ## 参数
209     ///
210     /// - `pcb` : 进程的pcb
211     ///
212     /// ## 返回值
213     ///
214     /// 无
215     pub fn add_pcb(pcb: Arc<ProcessControlBlock>) {
216         ALL_PROCESS
217             .lock_irqsave()
218             .as_mut()
219             .unwrap()
220             .insert(pcb.pid(), pcb.clone());
221     }
222 
223     /// 唤醒一个进程
224     pub fn wakeup(pcb: &Arc<ProcessControlBlock>) -> Result<(), SystemError> {
225         let _guard = unsafe { CurrentIrqArch::save_and_disable_irq() };
226         let state = pcb.sched_info().inner_lock_read_irqsave().state();
227         if state.is_blocked() {
228             let mut writer = pcb.sched_info().inner_lock_write_irqsave();
229             let state = writer.state();
230             if state.is_blocked() {
231                 writer.set_state(ProcessState::Runnable);
232                 writer.set_wakeup();
233 
234                 // avoid deadlock
235                 drop(writer);
236 
237                 let rq =
238                     cpu_rq(pcb.sched_info().on_cpu().unwrap_or(current_cpu_id()).data() as usize);
239 
240                 let (rq, _guard) = rq.self_lock();
241                 rq.update_rq_clock();
242                 rq.activate_task(
243                     pcb,
244                     EnqueueFlag::ENQUEUE_WAKEUP | EnqueueFlag::ENQUEUE_NOCLOCK,
245                 );
246 
247                 rq.check_preempt_currnet(pcb, WakeupFlags::empty());
248 
249                 // sched_enqueue(pcb.clone(), true);
250                 return Ok(());
251             } else if state.is_exited() {
252                 return Err(SystemError::EINVAL);
253             } else {
254                 return Ok(());
255             }
256         } else if state.is_exited() {
257             return Err(SystemError::EINVAL);
258         } else {
259             return Ok(());
260         }
261     }
262 
263     /// 唤醒暂停的进程
264     pub fn wakeup_stop(pcb: &Arc<ProcessControlBlock>) -> Result<(), SystemError> {
265         let _guard = unsafe { CurrentIrqArch::save_and_disable_irq() };
266         let state = pcb.sched_info().inner_lock_read_irqsave().state();
267         if let ProcessState::Stopped = state {
268             let mut writer = pcb.sched_info().inner_lock_write_irqsave();
269             let state = writer.state();
270             if let ProcessState::Stopped = state {
271                 writer.set_state(ProcessState::Runnable);
272                 // avoid deadlock
273                 drop(writer);
274 
275                 let rq = cpu_rq(pcb.sched_info().on_cpu().unwrap().data() as usize);
276 
277                 let (rq, _guard) = rq.self_lock();
278                 rq.update_rq_clock();
279                 rq.activate_task(
280                     pcb,
281                     EnqueueFlag::ENQUEUE_WAKEUP | EnqueueFlag::ENQUEUE_NOCLOCK,
282                 );
283 
284                 rq.check_preempt_currnet(pcb, WakeupFlags::empty());
285 
286                 // sched_enqueue(pcb.clone(), true);
287                 return Ok(());
288             } else if state.is_runnable() {
289                 return Ok(());
290             } else {
291                 return Err(SystemError::EINVAL);
292             }
293         } else if state.is_runnable() {
294             return Ok(());
295         } else {
296             return Err(SystemError::EINVAL);
297         }
298     }
299 
300     /// 标志当前进程永久睡眠,但是发起调度的工作,应该由调用者完成
301     ///
302     /// ## 注意
303     ///
304     /// - 进入当前函数之前,不能持有sched_info的锁
305     /// - 进入当前函数之前,必须关闭中断
306     /// - 进入当前函数之后必须保证逻辑的正确性,避免被重复加入调度队列
307     pub fn mark_sleep(interruptable: bool) -> Result<(), SystemError> {
308         assert!(
309             !CurrentIrqArch::is_irq_enabled(),
310             "interrupt must be disabled before enter ProcessManager::mark_sleep()"
311         );
312         let pcb = ProcessManager::current_pcb();
313         let mut writer = pcb.sched_info().inner_lock_write_irqsave();
314         if !matches!(writer.state(), ProcessState::Exited(_)) {
315             writer.set_state(ProcessState::Blocked(interruptable));
316             writer.set_sleep();
317             pcb.flags().insert(ProcessFlags::NEED_SCHEDULE);
318             fence(Ordering::SeqCst);
319             drop(writer);
320             return Ok(());
321         }
322         return Err(SystemError::EINTR);
323     }
324 
325     /// 标志当前进程为停止状态,但是发起调度的工作,应该由调用者完成
326     ///
327     /// ## 注意
328     ///
329     /// - 进入当前函数之前,不能持有sched_info的锁
330     /// - 进入当前函数之前,必须关闭中断
331     pub fn mark_stop() -> Result<(), SystemError> {
332         assert!(
333             !CurrentIrqArch::is_irq_enabled(),
334             "interrupt must be disabled before enter ProcessManager::mark_stop()"
335         );
336 
337         let pcb = ProcessManager::current_pcb();
338         let mut writer = pcb.sched_info().inner_lock_write_irqsave();
339         if !matches!(writer.state(), ProcessState::Exited(_)) {
340             writer.set_state(ProcessState::Stopped);
341             pcb.flags().insert(ProcessFlags::NEED_SCHEDULE);
342             drop(writer);
343 
344             return Ok(());
345         }
346         return Err(SystemError::EINTR);
347     }
348     /// 当子进程退出后向父进程发送通知
349     fn exit_notify() {
350         let current = ProcessManager::current_pcb();
351         // 让INIT进程收养所有子进程
352         if current.pid() != Pid(1) {
353             unsafe {
354                 current
355                     .adopt_childen()
356                     .unwrap_or_else(|e| panic!("adopte_childen failed: error: {e:?}"))
357             };
358             let r = current.parent_pcb.read_irqsave().upgrade();
359             if r.is_none() {
360                 return;
361             }
362             let parent_pcb = r.unwrap();
363             let r = Syscall::kill(parent_pcb.pid(), Signal::SIGCHLD as i32);
364             if r.is_err() {
365                 kwarn!(
366                     "failed to send kill signal to {:?}'s parent pcb {:?}",
367                     current.pid(),
368                     parent_pcb.pid()
369                 );
370             }
371             // todo: 这里需要向父进程发送SIGCHLD信号
372             // todo: 这里还需要根据线程组的信息,决定信号的发送
373         }
374     }
375 
376     /// 退出当前进程
377     ///
378     /// ## 参数
379     ///
380     /// - `exit_code` : 进程的退出码
381     pub fn exit(exit_code: usize) -> ! {
382         // 关中断
383         let _guard = unsafe { CurrentIrqArch::save_and_disable_irq() };
384         let pcb = ProcessManager::current_pcb();
385         let pid = pcb.pid();
386         pcb.sched_info
387             .inner_lock_write_irqsave()
388             .set_state(ProcessState::Exited(exit_code));
389         pcb.wait_queue.wakeup(Some(ProcessState::Blocked(true)));
390 
391         let rq = cpu_rq(smp_get_processor_id().data() as usize);
392         let (rq, guard) = rq.self_lock();
393         rq.deactivate_task(
394             pcb.clone(),
395             DequeueFlag::DEQUEUE_SLEEP | DequeueFlag::DEQUEUE_NOCLOCK,
396         );
397         drop(guard);
398 
399         // 进行进程退出后的工作
400         let thread = pcb.thread.write_irqsave();
401         if let Some(addr) = thread.set_child_tid {
402             unsafe { clear_user(addr, core::mem::size_of::<i32>()).expect("clear tid failed") };
403         }
404 
405         if let Some(addr) = thread.clear_child_tid {
406             if Arc::strong_count(&pcb.basic().user_vm().expect("User VM Not found")) > 1 {
407                 let _ =
408                     Futex::futex_wake(addr, FutexFlag::FLAGS_MATCH_NONE, 1, FUTEX_BITSET_MATCH_ANY);
409             }
410             unsafe { clear_user(addr, core::mem::size_of::<i32>()).expect("clear tid failed") };
411         }
412 
413         RobustListHead::exit_robust_list(pcb.clone());
414 
415         // 如果是vfork出来的进程,则需要处理completion
416         if thread.vfork_done.is_some() {
417             thread.vfork_done.as_ref().unwrap().complete_all();
418         }
419         drop(thread);
420         unsafe { pcb.basic_mut().set_user_vm(None) };
421         drop(pcb);
422         ProcessManager::exit_notify();
423         // unsafe { CurrentIrqArch::interrupt_enable() };
424         __schedule(SchedMode::SM_NONE);
425         kerror!("pid {pid:?} exited but sched again!");
426         #[allow(clippy::empty_loop)]
427         loop {
428             spin_loop();
429         }
430     }
431 
432     pub unsafe fn release(pid: Pid) {
433         let pcb = ProcessManager::find(pid);
434         if pcb.is_some() {
435             // let pcb = pcb.unwrap();
436             // 判断该pcb是否在全局没有任何引用
437             // TODO: 当前,pcb的Arc指针存在泄露问题,引用计数不正确,打算在接下来实现debug专用的Arc,方便调试,然后解决这个bug。
438             //          因此目前暂时注释掉,使得能跑
439             // if Arc::strong_count(&pcb) <= 2 {
440             //     drop(pcb);
441             //     ALL_PROCESS.lock().as_mut().unwrap().remove(&pid);
442             // } else {
443             //     // 如果不为1就panic
444             //     let msg = format!("pcb '{:?}' is still referenced, strong count={}",pcb.pid(),  Arc::strong_count(&pcb));
445             //     kerror!("{}", msg);
446             //     panic!()
447             // }
448 
449             ALL_PROCESS.lock_irqsave().as_mut().unwrap().remove(&pid);
450         }
451     }
452 
453     /// 上下文切换完成后的钩子函数
454     unsafe fn switch_finish_hook() {
455         // kdebug!("switch_finish_hook");
456         let prev_pcb = PROCESS_SWITCH_RESULT
457             .as_mut()
458             .unwrap()
459             .get_mut()
460             .prev_pcb
461             .take()
462             .expect("prev_pcb is None");
463         let next_pcb = PROCESS_SWITCH_RESULT
464             .as_mut()
465             .unwrap()
466             .get_mut()
467             .next_pcb
468             .take()
469             .expect("next_pcb is None");
470 
471         // 由于进程切换前使用了SpinLockGuard::leak(),所以这里需要手动释放锁
472         fence(Ordering::SeqCst);
473 
474         prev_pcb.arch_info.force_unlock();
475         fence(Ordering::SeqCst);
476 
477         next_pcb.arch_info.force_unlock();
478         fence(Ordering::SeqCst);
479     }
480 
481     /// 如果目标进程正在目标CPU上运行,那么就让这个cpu陷入内核态
482     ///
483     /// ## 参数
484     ///
485     /// - `pcb` : 进程的pcb
486     #[allow(dead_code)]
487     pub fn kick(pcb: &Arc<ProcessControlBlock>) {
488         ProcessManager::current_pcb().preempt_disable();
489         let cpu_id = pcb.sched_info().on_cpu();
490 
491         if let Some(cpu_id) = cpu_id {
492             if pcb.pid() == cpu_rq(cpu_id.data() as usize).current().pid() {
493                 kick_cpu(cpu_id).expect("ProcessManager::kick(): Failed to kick cpu");
494             }
495         }
496 
497         ProcessManager::current_pcb().preempt_enable();
498     }
499 }
500 
501 /// 上下文切换的钩子函数,当这个函数return的时候,将会发生上下文切换
502 #[cfg(target_arch = "x86_64")]
503 #[inline(never)]
504 pub unsafe extern "sysv64" fn switch_finish_hook() {
505     ProcessManager::switch_finish_hook();
506 }
507 #[cfg(target_arch = "riscv64")]
508 #[inline(always)]
509 pub unsafe fn switch_finish_hook() {
510     ProcessManager::switch_finish_hook();
511 }
512 
513 int_like!(Pid, AtomicPid, usize, AtomicUsize);
514 
515 impl ToString for Pid {
516     fn to_string(&self) -> String {
517         self.0.to_string()
518     }
519 }
520 
521 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
522 pub enum ProcessState {
523     /// The process is running on a CPU or in a run queue.
524     Runnable,
525     /// The process is waiting for an event to occur.
526     /// 其中的bool表示该等待过程是否可以被打断。
527     /// - 如果该bool为true,那么,硬件中断/信号/其他系统事件都可以打断该等待过程,使得该进程重新进入Runnable状态。
528     /// - 如果该bool为false,那么,这个进程必须被显式的唤醒,才能重新进入Runnable状态。
529     Blocked(bool),
530     /// 进程被信号终止
531     Stopped,
532     /// 进程已经退出,usize表示进程的退出码
533     Exited(usize),
534 }
535 
536 #[allow(dead_code)]
537 impl ProcessState {
538     #[inline(always)]
539     pub fn is_runnable(&self) -> bool {
540         return matches!(self, ProcessState::Runnable);
541     }
542 
543     #[inline(always)]
544     pub fn is_blocked(&self) -> bool {
545         return matches!(self, ProcessState::Blocked(_));
546     }
547 
548     #[inline(always)]
549     pub fn is_blocked_interruptable(&self) -> bool {
550         return matches!(self, ProcessState::Blocked(true));
551     }
552 
553     /// Returns `true` if the process state is [`Exited`].
554     #[inline(always)]
555     pub fn is_exited(&self) -> bool {
556         return matches!(self, ProcessState::Exited(_));
557     }
558 
559     /// Returns `true` if the process state is [`Stopped`].
560     ///
561     /// [`Stopped`]: ProcessState::Stopped
562     #[inline(always)]
563     pub fn is_stopped(&self) -> bool {
564         matches!(self, ProcessState::Stopped)
565     }
566 
567     /// Returns exit code if the process state is [`Exited`].
568     #[inline(always)]
569     pub fn exit_code(&self) -> Option<usize> {
570         match self {
571             ProcessState::Exited(code) => Some(*code),
572             _ => None,
573         }
574     }
575 }
576 
577 bitflags! {
578     /// pcb的标志位
579     pub struct ProcessFlags: usize {
580         /// 当前pcb表示一个内核线程
581         const KTHREAD = 1 << 0;
582         /// 当前进程需要被调度
583         const NEED_SCHEDULE = 1 << 1;
584         /// 进程由于vfork而与父进程存在资源共享
585         const VFORK = 1 << 2;
586         /// 进程不可被冻结
587         const NOFREEZE = 1 << 3;
588         /// 进程正在退出
589         const EXITING = 1 << 4;
590         /// 进程由于接收到终止信号唤醒
591         const WAKEKILL = 1 << 5;
592         /// 进程由于接收到信号而退出.(Killed by a signal)
593         const SIGNALED = 1 << 6;
594         /// 进程需要迁移到其他cpu上
595         const NEED_MIGRATE = 1 << 7;
596         /// 随机化的虚拟地址空间,主要用于动态链接器的加载
597         const RANDOMIZE = 1 << 8;
598     }
599 }
600 
601 #[derive(Debug)]
602 pub struct ProcessControlBlock {
603     /// 当前进程的pid
604     pid: Pid,
605     /// 当前进程的线程组id(这个值在同一个线程组内永远不变)
606     tgid: Pid,
607 
608     basic: RwLock<ProcessBasicInfo>,
609     /// 当前进程的自旋锁持有计数
610     preempt_count: AtomicUsize,
611 
612     flags: LockFreeFlags<ProcessFlags>,
613     worker_private: SpinLock<Option<WorkerPrivate>>,
614     /// 进程的内核栈
615     kernel_stack: RwLock<KernelStack>,
616 
617     /// 系统调用栈
618     syscall_stack: RwLock<KernelStack>,
619 
620     /// 与调度相关的信息
621     sched_info: ProcessSchedulerInfo,
622     /// 与处理器架构相关的信息
623     arch_info: SpinLock<ArchPCBInfo>,
624     /// 与信号处理相关的信息(似乎可以是无锁的)
625     sig_info: RwLock<ProcessSignalInfo>,
626     /// 信号处理结构体
627     sig_struct: SpinLock<SignalStruct>,
628     /// 退出信号S
629     exit_signal: AtomicSignal,
630 
631     /// 父进程指针
632     parent_pcb: RwLock<Weak<ProcessControlBlock>>,
633     /// 真实父进程指针
634     real_parent_pcb: RwLock<Weak<ProcessControlBlock>>,
635 
636     /// 子进程链表
637     children: RwLock<Vec<Pid>>,
638 
639     /// 等待队列
640     wait_queue: WaitQueue,
641 
642     /// 线程信息
643     thread: RwLock<ThreadInfo>,
644 
645     ///闹钟定时器
646     alarm_timer: SpinLock<Option<AlarmTimer>>,
647 
648     /// 进程的robust lock列表
649     robust_list: RwLock<Option<RobustListHead>>,
650 }
651 
652 impl ProcessControlBlock {
653     /// Generate a new pcb.
654     ///
655     /// ## 参数
656     ///
657     /// - `name` : 进程的名字
658     /// - `kstack` : 进程的内核栈
659     ///
660     /// ## 返回值
661     ///
662     /// 返回一个新的pcb
663     pub fn new(name: String, kstack: KernelStack) -> Arc<Self> {
664         return Self::do_create_pcb(name, kstack, false);
665     }
666 
667     /// 创建一个新的idle进程
668     ///
669     /// 请注意,这个函数只能在进程管理初始化的时候调用。
670     pub fn new_idle(cpu_id: u32, kstack: KernelStack) -> Arc<Self> {
671         let name = format!("idle-{}", cpu_id);
672         return Self::do_create_pcb(name, kstack, true);
673     }
674 
675     #[inline(never)]
676     fn do_create_pcb(name: String, kstack: KernelStack, is_idle: bool) -> Arc<Self> {
677         let (pid, ppid, cwd) = if is_idle {
678             (Pid(0), Pid(0), "/".to_string())
679         } else {
680             let ppid = ProcessManager::current_pcb().pid();
681             let cwd = ProcessManager::current_pcb().basic().cwd();
682             (Self::generate_pid(), ppid, cwd)
683         };
684 
685         let basic_info = ProcessBasicInfo::new(Pid(0), ppid, name, cwd, None);
686         let preempt_count = AtomicUsize::new(0);
687         let flags = unsafe { LockFreeFlags::new(ProcessFlags::empty()) };
688 
689         let sched_info = ProcessSchedulerInfo::new(None);
690         let arch_info = SpinLock::new(ArchPCBInfo::new(&kstack));
691 
692         let ppcb: Weak<ProcessControlBlock> = ProcessManager::find(ppid)
693             .map(|p| Arc::downgrade(&p))
694             .unwrap_or_default();
695 
696         let pcb = Self {
697             pid,
698             tgid: pid,
699             basic: basic_info,
700             preempt_count,
701             flags,
702             kernel_stack: RwLock::new(kstack),
703             syscall_stack: RwLock::new(KernelStack::new().unwrap()),
704             worker_private: SpinLock::new(None),
705             sched_info,
706             arch_info,
707             sig_info: RwLock::new(ProcessSignalInfo::default()),
708             sig_struct: SpinLock::new(SignalStruct::new()),
709             exit_signal: AtomicSignal::new(Signal::SIGCHLD),
710             parent_pcb: RwLock::new(ppcb.clone()),
711             real_parent_pcb: RwLock::new(ppcb),
712             children: RwLock::new(Vec::new()),
713             wait_queue: WaitQueue::default(),
714             thread: RwLock::new(ThreadInfo::new()),
715             alarm_timer: SpinLock::new(None),
716             robust_list: RwLock::new(None),
717         };
718 
719         // 初始化系统调用栈
720         #[cfg(target_arch = "x86_64")]
721         pcb.arch_info
722             .lock()
723             .init_syscall_stack(&pcb.syscall_stack.read());
724 
725         let pcb = Arc::new(pcb);
726 
727         pcb.sched_info()
728             .sched_entity()
729             .force_mut()
730             .set_pcb(Arc::downgrade(&pcb));
731         // 设置进程的arc指针到内核栈和系统调用栈的最低地址处
732         unsafe {
733             pcb.kernel_stack
734                 .write()
735                 .set_pcb(Arc::downgrade(&pcb))
736                 .unwrap();
737 
738             pcb.syscall_stack
739                 .write()
740                 .set_pcb(Arc::downgrade(&pcb))
741                 .unwrap()
742         };
743 
744         // 将当前pcb加入父进程的子进程哈希表中
745         if pcb.pid() > Pid(1) {
746             if let Some(ppcb_arc) = pcb.parent_pcb.read_irqsave().upgrade() {
747                 let mut children = ppcb_arc.children.write_irqsave();
748                 children.push(pcb.pid());
749             } else {
750                 panic!("parent pcb is None");
751             }
752         }
753 
754         return pcb;
755     }
756 
757     /// 生成一个新的pid
758     #[inline(always)]
759     fn generate_pid() -> Pid {
760         static NEXT_PID: AtomicPid = AtomicPid::new(Pid(1));
761         return NEXT_PID.fetch_add(Pid(1), Ordering::SeqCst);
762     }
763 
764     /// 返回当前进程的锁持有计数
765     #[inline(always)]
766     pub fn preempt_count(&self) -> usize {
767         return self.preempt_count.load(Ordering::SeqCst);
768     }
769 
770     /// 增加当前进程的锁持有计数
771     #[inline(always)]
772     pub fn preempt_disable(&self) {
773         self.preempt_count.fetch_add(1, Ordering::SeqCst);
774     }
775 
776     /// 减少当前进程的锁持有计数
777     #[inline(always)]
778     pub fn preempt_enable(&self) {
779         self.preempt_count.fetch_sub(1, Ordering::SeqCst);
780     }
781 
782     #[inline(always)]
783     pub unsafe fn set_preempt_count(&self, count: usize) {
784         self.preempt_count.store(count, Ordering::SeqCst);
785     }
786 
787     #[inline(always)]
788     pub fn flags(&self) -> &mut ProcessFlags {
789         return self.flags.get_mut();
790     }
791 
792     /// 请注意,这个值能在中断上下文中读取,但不能被中断上下文修改
793     /// 否则会导致死锁
794     #[inline(always)]
795     pub fn basic(&self) -> RwLockReadGuard<ProcessBasicInfo> {
796         return self.basic.read_irqsave();
797     }
798 
799     #[inline(always)]
800     pub fn set_name(&self, name: String) {
801         self.basic.write().set_name(name);
802     }
803 
804     #[inline(always)]
805     pub fn basic_mut(&self) -> RwLockWriteGuard<ProcessBasicInfo> {
806         return self.basic.write_irqsave();
807     }
808 
809     /// # 获取arch info的锁,同时关闭中断
810     #[inline(always)]
811     pub fn arch_info_irqsave(&self) -> SpinLockGuard<ArchPCBInfo> {
812         return self.arch_info.lock_irqsave();
813     }
814 
815     /// # 获取arch info的锁,但是不关闭中断
816     ///
817     /// 由于arch info在进程切换的时候会使用到,
818     /// 因此在中断上下文外,获取arch info 而不irqsave是不安全的.
819     ///
820     /// 只能在以下情况下使用这个函数:
821     /// - 在中断上下文中(中断已经禁用),获取arch info的锁。
822     /// - 刚刚创建新的pcb
823     #[inline(always)]
824     pub unsafe fn arch_info(&self) -> SpinLockGuard<ArchPCBInfo> {
825         return self.arch_info.lock();
826     }
827 
828     #[inline(always)]
829     pub fn kernel_stack(&self) -> RwLockReadGuard<KernelStack> {
830         return self.kernel_stack.read();
831     }
832 
833     pub unsafe fn kernel_stack_force_ref(&self) -> &KernelStack {
834         self.kernel_stack.force_get_ref()
835     }
836 
837     #[inline(always)]
838     #[allow(dead_code)]
839     pub fn kernel_stack_mut(&self) -> RwLockWriteGuard<KernelStack> {
840         return self.kernel_stack.write();
841     }
842 
843     #[inline(always)]
844     pub fn sched_info(&self) -> &ProcessSchedulerInfo {
845         return &self.sched_info;
846     }
847 
848     #[inline(always)]
849     pub fn worker_private(&self) -> SpinLockGuard<Option<WorkerPrivate>> {
850         return self.worker_private.lock();
851     }
852 
853     #[inline(always)]
854     pub fn pid(&self) -> Pid {
855         return self.pid;
856     }
857 
858     #[inline(always)]
859     pub fn tgid(&self) -> Pid {
860         return self.tgid;
861     }
862 
863     /// 获取文件描述符表的Arc指针
864     #[inline(always)]
865     pub fn fd_table(&self) -> Arc<RwLock<FileDescriptorVec>> {
866         return self.basic.read().fd_table().unwrap();
867     }
868 
869     /// 根据文件描述符序号,获取socket对象的Arc指针
870     ///
871     /// ## 参数
872     ///
873     /// - `fd` 文件描述符序号
874     ///
875     /// ## 返回值
876     ///
877     /// Option(&mut Box<dyn Socket>) socket对象的可变引用. 如果文件描述符不是socket,那么返回None
878     pub fn get_socket(&self, fd: i32) -> Option<Arc<SocketInode>> {
879         let binding = ProcessManager::current_pcb().fd_table();
880         let fd_table_guard = binding.read();
881 
882         let f = fd_table_guard.get_file_by_fd(fd)?;
883         drop(fd_table_guard);
884 
885         if f.file_type() != FileType::Socket {
886             return None;
887         }
888         let socket: Arc<SocketInode> = f
889             .inode()
890             .downcast_arc::<SocketInode>()
891             .expect("Not a socket inode");
892         return Some(socket);
893     }
894 
895     /// 当前进程退出时,让初始进程收养所有子进程
896     unsafe fn adopt_childen(&self) -> Result<(), SystemError> {
897         match ProcessManager::find(Pid(1)) {
898             Some(init_pcb) => {
899                 let childen_guard = self.children.write();
900                 let mut init_childen_guard = init_pcb.children.write();
901 
902                 childen_guard.iter().for_each(|pid| {
903                     init_childen_guard.push(*pid);
904                 });
905 
906                 return Ok(());
907             }
908             _ => Err(SystemError::ECHILD),
909         }
910     }
911 
912     /// 生成进程的名字
913     pub fn generate_name(program_path: &str, args: &Vec<String>) -> String {
914         let mut name = program_path.to_string();
915         for arg in args {
916             name.push(' ');
917             name.push_str(arg);
918         }
919         return name;
920     }
921 
922     pub fn sig_info_irqsave(&self) -> RwLockReadGuard<ProcessSignalInfo> {
923         self.sig_info.read_irqsave()
924     }
925 
926     pub fn try_siginfo_irqsave(&self, times: u8) -> Option<RwLockReadGuard<ProcessSignalInfo>> {
927         for _ in 0..times {
928             if let Some(r) = self.sig_info.try_read_irqsave() {
929                 return Some(r);
930             }
931         }
932 
933         return None;
934     }
935 
936     pub fn sig_info_mut(&self) -> RwLockWriteGuard<ProcessSignalInfo> {
937         self.sig_info.write_irqsave()
938     }
939 
940     pub fn try_siginfo_mut(&self, times: u8) -> Option<RwLockWriteGuard<ProcessSignalInfo>> {
941         for _ in 0..times {
942             if let Some(r) = self.sig_info.try_write_irqsave() {
943                 return Some(r);
944             }
945         }
946 
947         return None;
948     }
949 
950     pub fn sig_struct(&self) -> SpinLockGuard<SignalStruct> {
951         self.sig_struct.lock_irqsave()
952     }
953 
954     pub fn try_sig_struct_irqsave(&self, times: u8) -> Option<SpinLockGuard<SignalStruct>> {
955         for _ in 0..times {
956             if let Ok(r) = self.sig_struct.try_lock_irqsave() {
957                 return Some(r);
958             }
959         }
960 
961         return None;
962     }
963 
964     pub fn sig_struct_irqsave(&self) -> SpinLockGuard<SignalStruct> {
965         self.sig_struct.lock_irqsave()
966     }
967 
968     #[inline(always)]
969     pub fn get_robust_list(&self) -> RwLockReadGuard<Option<RobustListHead>> {
970         return self.robust_list.read_irqsave();
971     }
972 
973     #[inline(always)]
974     pub fn set_robust_list(&self, new_robust_list: Option<RobustListHead>) {
975         *self.robust_list.write_irqsave() = new_robust_list;
976     }
977 
978     pub fn alarm_timer_irqsave(&self) -> SpinLockGuard<Option<AlarmTimer>> {
979         return self.alarm_timer.lock_irqsave();
980     }
981 }
982 
983 impl Drop for ProcessControlBlock {
984     fn drop(&mut self) {
985         let irq_guard = unsafe { CurrentIrqArch::save_and_disable_irq() };
986         // 在ProcFS中,解除进程的注册
987         procfs_unregister_pid(self.pid())
988             .unwrap_or_else(|e| panic!("procfs_unregister_pid failed: error: {e:?}"));
989 
990         if let Some(ppcb) = self.parent_pcb.read_irqsave().upgrade() {
991             ppcb.children
992                 .write_irqsave()
993                 .retain(|pid| *pid != self.pid());
994         }
995 
996         drop(irq_guard);
997     }
998 }
999 
1000 /// 线程信息
1001 #[derive(Debug)]
1002 pub struct ThreadInfo {
1003     // 来自用户空间记录用户线程id的地址,在该线程结束时将该地址置0以通知父进程
1004     clear_child_tid: Option<VirtAddr>,
1005     set_child_tid: Option<VirtAddr>,
1006 
1007     vfork_done: Option<Arc<Completion>>,
1008     /// 线程组的组长
1009     group_leader: Weak<ProcessControlBlock>,
1010 }
1011 
1012 impl ThreadInfo {
1013     pub fn new() -> Self {
1014         Self {
1015             clear_child_tid: None,
1016             set_child_tid: None,
1017             vfork_done: None,
1018             group_leader: Weak::default(),
1019         }
1020     }
1021 
1022     pub fn group_leader(&self) -> Option<Arc<ProcessControlBlock>> {
1023         return self.group_leader.upgrade();
1024     }
1025 }
1026 
1027 /// 进程的基本信息
1028 ///
1029 /// 这个结构体保存进程的基本信息,主要是那些不会随着进程的运行而经常改变的信息。
1030 #[derive(Debug)]
1031 pub struct ProcessBasicInfo {
1032     /// 当前进程的进程组id
1033     pgid: Pid,
1034     /// 当前进程的父进程的pid
1035     ppid: Pid,
1036     /// 进程的名字
1037     name: String,
1038 
1039     /// 当前进程的工作目录
1040     cwd: String,
1041 
1042     /// 用户地址空间
1043     user_vm: Option<Arc<AddressSpace>>,
1044 
1045     /// 文件描述符表
1046     fd_table: Option<Arc<RwLock<FileDescriptorVec>>>,
1047 }
1048 
1049 impl ProcessBasicInfo {
1050     #[inline(never)]
1051     pub fn new(
1052         pgid: Pid,
1053         ppid: Pid,
1054         name: String,
1055         cwd: String,
1056         user_vm: Option<Arc<AddressSpace>>,
1057     ) -> RwLock<Self> {
1058         let fd_table = Arc::new(RwLock::new(FileDescriptorVec::new()));
1059         return RwLock::new(Self {
1060             pgid,
1061             ppid,
1062             name,
1063             cwd,
1064             user_vm,
1065             fd_table: Some(fd_table),
1066         });
1067     }
1068 
1069     pub fn pgid(&self) -> Pid {
1070         return self.pgid;
1071     }
1072 
1073     pub fn ppid(&self) -> Pid {
1074         return self.ppid;
1075     }
1076 
1077     pub fn name(&self) -> &str {
1078         return &self.name;
1079     }
1080 
1081     pub fn set_name(&mut self, name: String) {
1082         self.name = name;
1083     }
1084 
1085     pub fn cwd(&self) -> String {
1086         return self.cwd.clone();
1087     }
1088     pub fn set_cwd(&mut self, path: String) {
1089         return self.cwd = path;
1090     }
1091 
1092     pub fn user_vm(&self) -> Option<Arc<AddressSpace>> {
1093         return self.user_vm.clone();
1094     }
1095 
1096     pub unsafe fn set_user_vm(&mut self, user_vm: Option<Arc<AddressSpace>>) {
1097         self.user_vm = user_vm;
1098     }
1099 
1100     pub fn fd_table(&self) -> Option<Arc<RwLock<FileDescriptorVec>>> {
1101         return self.fd_table.clone();
1102     }
1103 
1104     pub fn set_fd_table(&mut self, fd_table: Option<Arc<RwLock<FileDescriptorVec>>>) {
1105         self.fd_table = fd_table;
1106     }
1107 }
1108 
1109 #[derive(Debug)]
1110 pub struct ProcessSchedulerInfo {
1111     /// 当前进程所在的cpu
1112     on_cpu: AtomicProcessorId,
1113     /// 如果当前进程等待被迁移到另一个cpu核心上(也就是flags中的PF_NEED_MIGRATE被置位),
1114     /// 该字段存储要被迁移到的目标处理器核心号
1115     // migrate_to: AtomicProcessorId,
1116     inner_locked: RwLock<InnerSchedInfo>,
1117     /// 进程的调度优先级
1118     // priority: SchedPriority,
1119     /// 当前进程的虚拟运行时间
1120     // virtual_runtime: AtomicIsize,
1121     /// 由实时调度器管理的时间片
1122     // rt_time_slice: AtomicIsize,
1123     pub sched_stat: RwLock<SchedInfo>,
1124     /// 调度策略
1125     pub sched_policy: RwLock<crate::sched::SchedPolicy>,
1126     /// cfs调度实体
1127     pub sched_entity: Arc<FairSchedEntity>,
1128     pub on_rq: SpinLock<OnRq>,
1129 
1130     pub prio_data: RwLock<PrioData>,
1131 }
1132 
1133 #[derive(Debug, Default)]
1134 pub struct SchedInfo {
1135     /// 记录任务在特定 CPU 上运行的次数
1136     pub pcount: usize,
1137     /// 记录任务等待在运行队列上的时间
1138     pub run_delay: usize,
1139     /// 记录任务上次在 CPU 上运行的时间戳
1140     pub last_arrival: u64,
1141     /// 记录任务上次被加入到运行队列中的时间戳
1142     pub last_queued: u64,
1143 }
1144 
1145 #[derive(Debug)]
1146 pub struct PrioData {
1147     pub prio: i32,
1148     pub static_prio: i32,
1149     pub normal_prio: i32,
1150 }
1151 
1152 impl Default for PrioData {
1153     fn default() -> Self {
1154         Self {
1155             prio: MAX_PRIO - 20,
1156             static_prio: MAX_PRIO - 20,
1157             normal_prio: MAX_PRIO - 20,
1158         }
1159     }
1160 }
1161 
1162 #[derive(Debug)]
1163 pub struct InnerSchedInfo {
1164     /// 当前进程的状态
1165     state: ProcessState,
1166     /// 进程的调度策略
1167     sleep: bool,
1168 }
1169 
1170 impl InnerSchedInfo {
1171     pub fn state(&self) -> ProcessState {
1172         return self.state;
1173     }
1174 
1175     pub fn set_state(&mut self, state: ProcessState) {
1176         self.state = state;
1177     }
1178 
1179     pub fn set_sleep(&mut self) {
1180         self.sleep = true;
1181     }
1182 
1183     pub fn set_wakeup(&mut self) {
1184         self.sleep = false;
1185     }
1186 
1187     pub fn is_mark_sleep(&self) -> bool {
1188         self.sleep
1189     }
1190 }
1191 
1192 impl ProcessSchedulerInfo {
1193     #[inline(never)]
1194     pub fn new(on_cpu: Option<ProcessorId>) -> Self {
1195         let cpu_id = on_cpu.unwrap_or(ProcessorId::INVALID);
1196         return Self {
1197             on_cpu: AtomicProcessorId::new(cpu_id),
1198             // migrate_to: AtomicProcessorId::new(ProcessorId::INVALID),
1199             inner_locked: RwLock::new(InnerSchedInfo {
1200                 state: ProcessState::Blocked(false),
1201                 sleep: false,
1202             }),
1203             // virtual_runtime: AtomicIsize::new(0),
1204             // rt_time_slice: AtomicIsize::new(0),
1205             // priority: SchedPriority::new(100).unwrap(),
1206             sched_stat: RwLock::new(SchedInfo::default()),
1207             sched_policy: RwLock::new(crate::sched::SchedPolicy::CFS),
1208             sched_entity: FairSchedEntity::new(),
1209             on_rq: SpinLock::new(OnRq::None),
1210             prio_data: RwLock::new(PrioData::default()),
1211         };
1212     }
1213 
1214     pub fn sched_entity(&self) -> Arc<FairSchedEntity> {
1215         return self.sched_entity.clone();
1216     }
1217 
1218     pub fn on_cpu(&self) -> Option<ProcessorId> {
1219         let on_cpu = self.on_cpu.load(Ordering::SeqCst);
1220         if on_cpu == ProcessorId::INVALID {
1221             return None;
1222         } else {
1223             return Some(on_cpu);
1224         }
1225     }
1226 
1227     pub fn set_on_cpu(&self, on_cpu: Option<ProcessorId>) {
1228         if let Some(cpu_id) = on_cpu {
1229             self.on_cpu.store(cpu_id, Ordering::SeqCst);
1230         } else {
1231             self.on_cpu.store(ProcessorId::INVALID, Ordering::SeqCst);
1232         }
1233     }
1234 
1235     // pub fn migrate_to(&self) -> Option<ProcessorId> {
1236     //     let migrate_to = self.migrate_to.load(Ordering::SeqCst);
1237     //     if migrate_to == ProcessorId::INVALID {
1238     //         return None;
1239     //     } else {
1240     //         return Some(migrate_to);
1241     //     }
1242     // }
1243 
1244     // pub fn set_migrate_to(&self, migrate_to: Option<ProcessorId>) {
1245     //     if let Some(data) = migrate_to {
1246     //         self.migrate_to.store(data, Ordering::SeqCst);
1247     //     } else {
1248     //         self.migrate_to
1249     //             .store(ProcessorId::INVALID, Ordering::SeqCst)
1250     //     }
1251     // }
1252 
1253     pub fn inner_lock_write_irqsave(&self) -> RwLockWriteGuard<InnerSchedInfo> {
1254         return self.inner_locked.write_irqsave();
1255     }
1256 
1257     pub fn inner_lock_read_irqsave(&self) -> RwLockReadGuard<InnerSchedInfo> {
1258         return self.inner_locked.read_irqsave();
1259     }
1260 
1261     // pub fn inner_lock_try_read_irqsave(
1262     //     &self,
1263     //     times: u8,
1264     // ) -> Option<RwLockReadGuard<InnerSchedInfo>> {
1265     //     for _ in 0..times {
1266     //         if let Some(r) = self.inner_locked.try_read_irqsave() {
1267     //             return Some(r);
1268     //         }
1269     //     }
1270 
1271     //     return None;
1272     // }
1273 
1274     // pub fn inner_lock_try_upgradable_read_irqsave(
1275     //     &self,
1276     //     times: u8,
1277     // ) -> Option<RwLockUpgradableGuard<InnerSchedInfo>> {
1278     //     for _ in 0..times {
1279     //         if let Some(r) = self.inner_locked.try_upgradeable_read_irqsave() {
1280     //             return Some(r);
1281     //         }
1282     //     }
1283 
1284     //     return None;
1285     // }
1286 
1287     // pub fn virtual_runtime(&self) -> isize {
1288     //     return self.virtual_runtime.load(Ordering::SeqCst);
1289     // }
1290 
1291     // pub fn set_virtual_runtime(&self, virtual_runtime: isize) {
1292     //     self.virtual_runtime
1293     //         .store(virtual_runtime, Ordering::SeqCst);
1294     // }
1295     // pub fn increase_virtual_runtime(&self, delta: isize) {
1296     //     self.virtual_runtime.fetch_add(delta, Ordering::SeqCst);
1297     // }
1298 
1299     // pub fn rt_time_slice(&self) -> isize {
1300     //     return self.rt_time_slice.load(Ordering::SeqCst);
1301     // }
1302 
1303     // pub fn set_rt_time_slice(&self, rt_time_slice: isize) {
1304     //     self.rt_time_slice.store(rt_time_slice, Ordering::SeqCst);
1305     // }
1306 
1307     // pub fn increase_rt_time_slice(&self, delta: isize) {
1308     //     self.rt_time_slice.fetch_add(delta, Ordering::SeqCst);
1309     // }
1310 
1311     pub fn policy(&self) -> crate::sched::SchedPolicy {
1312         return *self.sched_policy.read_irqsave();
1313     }
1314 }
1315 
1316 #[derive(Debug, Clone)]
1317 pub struct KernelStack {
1318     stack: Option<AlignedBox<[u8; KernelStack::SIZE], { KernelStack::ALIGN }>>,
1319     /// 标记该内核栈是否可以被释放
1320     can_be_freed: bool,
1321 }
1322 
1323 impl KernelStack {
1324     pub const SIZE: usize = 0x4000;
1325     pub const ALIGN: usize = 0x4000;
1326 
1327     pub fn new() -> Result<Self, SystemError> {
1328         return Ok(Self {
1329             stack: Some(
1330                 AlignedBox::<[u8; KernelStack::SIZE], { KernelStack::ALIGN }>::new_zeroed()?,
1331             ),
1332             can_be_freed: true,
1333         });
1334     }
1335 
1336     /// 根据已有的空间,构造一个内核栈结构体
1337     ///
1338     /// 仅仅用于BSP启动时,为idle进程构造内核栈。其他时候使用这个函数,很可能造成错误!
1339     pub unsafe fn from_existed(base: VirtAddr) -> Result<Self, SystemError> {
1340         if base.is_null() || !base.check_aligned(Self::ALIGN) {
1341             return Err(SystemError::EFAULT);
1342         }
1343 
1344         return Ok(Self {
1345             stack: Some(
1346                 AlignedBox::<[u8; KernelStack::SIZE], { KernelStack::ALIGN }>::new_unchecked(
1347                     base.data() as *mut [u8; KernelStack::SIZE],
1348                 ),
1349             ),
1350             can_be_freed: false,
1351         });
1352     }
1353 
1354     /// 返回内核栈的起始虚拟地址(低地址)
1355     pub fn start_address(&self) -> VirtAddr {
1356         return VirtAddr::new(self.stack.as_ref().unwrap().as_ptr() as usize);
1357     }
1358 
1359     /// 返回内核栈的结束虚拟地址(高地址)(不包含该地址)
1360     pub fn stack_max_address(&self) -> VirtAddr {
1361         return VirtAddr::new(self.stack.as_ref().unwrap().as_ptr() as usize + Self::SIZE);
1362     }
1363 
1364     pub unsafe fn set_pcb(&mut self, pcb: Weak<ProcessControlBlock>) -> Result<(), SystemError> {
1365         // 将一个Weak<ProcessControlBlock>放到内核栈的最低地址处
1366         let p: *const ProcessControlBlock = Weak::into_raw(pcb);
1367         let stack_bottom_ptr = self.start_address().data() as *mut *const ProcessControlBlock;
1368 
1369         // 如果内核栈的最低地址处已经有了一个pcb,那么,这里就不再设置,直接返回错误
1370         if unlikely(unsafe { !(*stack_bottom_ptr).is_null() }) {
1371             kerror!("kernel stack bottom is not null: {:p}", *stack_bottom_ptr);
1372             return Err(SystemError::EPERM);
1373         }
1374         // 将pcb的地址放到内核栈的最低地址处
1375         unsafe {
1376             *stack_bottom_ptr = p;
1377         }
1378 
1379         return Ok(());
1380     }
1381 
1382     /// 清除内核栈的pcb指针
1383     ///
1384     /// ## 参数
1385     ///
1386     /// - `force` : 如果为true,那么,即使该内核栈的pcb指针不为null,也会被强制清除而不处理Weak指针问题
1387     pub unsafe fn clear_pcb(&mut self, force: bool) {
1388         let stack_bottom_ptr = self.start_address().data() as *mut *const ProcessControlBlock;
1389         if unlikely(unsafe { (*stack_bottom_ptr).is_null() }) {
1390             return;
1391         }
1392 
1393         if !force {
1394             let pcb_ptr: Weak<ProcessControlBlock> = Weak::from_raw(*stack_bottom_ptr);
1395             drop(pcb_ptr);
1396         }
1397 
1398         *stack_bottom_ptr = core::ptr::null();
1399     }
1400 
1401     /// 返回指向当前内核栈pcb的Arc指针
1402     #[allow(dead_code)]
1403     pub unsafe fn pcb(&self) -> Option<Arc<ProcessControlBlock>> {
1404         // 从内核栈的最低地址处取出pcb的地址
1405         let p = self.stack.as_ref().unwrap().as_ptr() as *const *const ProcessControlBlock;
1406         if unlikely(unsafe { (*p).is_null() }) {
1407             return None;
1408         }
1409 
1410         // 为了防止内核栈的pcb指针被释放,这里需要将其包装一下,使得Arc的drop不会被调用
1411         let weak_wrapper: ManuallyDrop<Weak<ProcessControlBlock>> =
1412             ManuallyDrop::new(Weak::from_raw(*p));
1413 
1414         let new_arc: Arc<ProcessControlBlock> = weak_wrapper.upgrade()?;
1415         return Some(new_arc);
1416     }
1417 }
1418 
1419 impl Drop for KernelStack {
1420     fn drop(&mut self) {
1421         if self.stack.is_some() {
1422             let ptr = self.stack.as_ref().unwrap().as_ptr() as *const *const ProcessControlBlock;
1423             if unsafe { !(*ptr).is_null() } {
1424                 let pcb_ptr: Weak<ProcessControlBlock> = unsafe { Weak::from_raw(*ptr) };
1425                 drop(pcb_ptr);
1426             }
1427         }
1428         // 如果该内核栈不可以被释放,那么,这里就forget,不调用AlignedBox的drop函数
1429         if !self.can_be_freed {
1430             let bx = self.stack.take();
1431             core::mem::forget(bx);
1432         }
1433     }
1434 }
1435 
1436 pub fn process_init() {
1437     ProcessManager::init();
1438 }
1439 
1440 #[derive(Debug)]
1441 pub struct ProcessSignalInfo {
1442     // 当前进程
1443     sig_block: SigSet,
1444     // sig_pending 中存储当前线程要处理的信号
1445     sig_pending: SigPending,
1446     // sig_shared_pending 中存储当前线程所属进程要处理的信号
1447     sig_shared_pending: SigPending,
1448     // 当前进程对应的tty
1449     tty: Option<Arc<TtyCore>>,
1450 }
1451 
1452 impl ProcessSignalInfo {
1453     pub fn sig_block(&self) -> &SigSet {
1454         &self.sig_block
1455     }
1456 
1457     pub fn sig_pending(&self) -> &SigPending {
1458         &self.sig_pending
1459     }
1460 
1461     pub fn sig_pending_mut(&mut self) -> &mut SigPending {
1462         &mut self.sig_pending
1463     }
1464 
1465     pub fn sig_block_mut(&mut self) -> &mut SigSet {
1466         &mut self.sig_block
1467     }
1468 
1469     pub fn sig_shared_pending_mut(&mut self) -> &mut SigPending {
1470         &mut self.sig_shared_pending
1471     }
1472 
1473     pub fn sig_shared_pending(&self) -> &SigPending {
1474         &self.sig_shared_pending
1475     }
1476 
1477     pub fn tty(&self) -> Option<Arc<TtyCore>> {
1478         self.tty.clone()
1479     }
1480 
1481     pub fn set_tty(&mut self, tty: Arc<TtyCore>) {
1482         self.tty = Some(tty);
1483     }
1484 
1485     /// 从 pcb 的 siginfo中取出下一个要处理的信号,先处理线程信号,再处理进程信号
1486     ///
1487     /// ## 参数
1488     ///
1489     /// - `sig_mask` 被忽略掉的信号
1490     ///
1491     pub fn dequeue_signal(&mut self, sig_mask: &SigSet) -> (Signal, Option<SigInfo>) {
1492         let res = self.sig_pending.dequeue_signal(sig_mask);
1493         if res.0 != Signal::INVALID {
1494             return res;
1495         } else {
1496             return self.sig_shared_pending.dequeue_signal(sig_mask);
1497         }
1498     }
1499 }
1500 
1501 impl Default for ProcessSignalInfo {
1502     fn default() -> Self {
1503         Self {
1504             sig_block: SigSet::empty(),
1505             sig_pending: SigPending::default(),
1506             sig_shared_pending: SigPending::default(),
1507             tty: None,
1508         }
1509     }
1510 }
1511