xref: /DragonOS/kernel/src/process/mod.rs (revision b2ca6800f9d943e5d3656d9b50a099da768775a7)
1 use core::{
2     hash::{Hash, Hasher},
3     hint::spin_loop,
4     intrinsics::{likely, unlikely},
5     mem::ManuallyDrop,
6     sync::atomic::{compiler_fence, AtomicBool, AtomicI32, AtomicIsize, 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         ipc::signal::{AtomicSignal, SigSet, Signal},
20         process::ArchPCBInfo,
21         sched::sched,
22         CurrentIrqArch,
23     },
24     exception::InterruptArch,
25     filesystem::{
26         procfs::procfs_unregister_pid,
27         vfs::{file::FileDescriptorVec, FileType},
28     },
29     ipc::signal_types::{SigInfo, SigPending, SignalStruct},
30     kdebug, kinfo,
31     libs::{
32         align::AlignedBox,
33         casting::DowncastArc,
34         futex::{
35             constant::{FutexFlag, FUTEX_BITSET_MATCH_ANY},
36             futex::Futex,
37         },
38         lock_free_flags::LockFreeFlags,
39         rwlock::{RwLock, RwLockReadGuard, RwLockUpgradableGuard, RwLockWriteGuard},
40         spinlock::{SpinLock, SpinLockGuard},
41         wait_queue::WaitQueue,
42     },
43     mm::{percpu::PerCpuVar, set_INITIAL_PROCESS_ADDRESS_SPACE, ucontext::AddressSpace, VirtAddr},
44     net::socket::SocketInode,
45     sched::{
46         completion::Completion,
47         core::{sched_enqueue, CPU_EXECUTING},
48         SchedPolicy, SchedPriority,
49     },
50     smp::kick_cpu,
51     syscall::{user_access::clear_user, Syscall},
52 };
53 
54 use self::kthread::WorkerPrivate;
55 
56 pub mod abi;
57 pub mod c_adapter;
58 pub mod exec;
59 pub mod exit;
60 pub mod fork;
61 pub mod idle;
62 pub mod kthread;
63 pub mod pid;
64 pub mod process;
65 pub mod resource;
66 pub mod syscall;
67 
68 /// 系统中所有进程的pcb
69 static ALL_PROCESS: SpinLock<Option<HashMap<Pid, Arc<ProcessControlBlock>>>> = SpinLock::new(None);
70 
71 pub static mut SWITCH_RESULT: Option<PerCpuVar<SwitchResult>> = None;
72 
73 /// 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
74 static mut __PROCESS_MANAGEMENT_INIT_DONE: bool = false;
75 
76 #[derive(Debug)]
77 pub struct SwitchResult {
78     pub prev_pcb: Option<Arc<ProcessControlBlock>>,
79     pub next_pcb: Option<Arc<ProcessControlBlock>>,
80 }
81 
82 impl SwitchResult {
83     pub fn new() -> Self {
84         Self {
85             prev_pcb: None,
86             next_pcb: None,
87         }
88     }
89 }
90 
91 #[derive(Debug)]
92 pub struct ProcessManager;
93 impl ProcessManager {
94     #[inline(never)]
95     fn init() {
96         static INIT_FLAG: AtomicBool = AtomicBool::new(false);
97         if INIT_FLAG
98             .compare_exchange(false, true, Ordering::SeqCst, Ordering::SeqCst)
99             .is_err()
100         {
101             panic!("ProcessManager has been initialized!");
102         }
103 
104         unsafe {
105             compiler_fence(Ordering::SeqCst);
106             kdebug!("To create address space for INIT process.");
107             // test_buddy();
108             set_INITIAL_PROCESS_ADDRESS_SPACE(
109                 AddressSpace::new(true).expect("Failed to create address space for INIT process."),
110             );
111             kdebug!("INIT process address space created.");
112             compiler_fence(Ordering::SeqCst);
113         };
114 
115         ALL_PROCESS.lock_irqsave().replace(HashMap::new());
116         Self::arch_init();
117         kdebug!("process arch init done.");
118         Self::init_idle();
119         kdebug!("process idle init done.");
120 
121         unsafe { __PROCESS_MANAGEMENT_INIT_DONE = true };
122         kinfo!("Process Manager initialized.");
123     }
124 
125     /// 判断进程管理器是否已经初始化完成
126     pub fn initialized() -> bool {
127         unsafe { __PROCESS_MANAGEMENT_INIT_DONE }
128     }
129 
130     /// 获取当前进程的pcb
131     pub fn current_pcb() -> Arc<ProcessControlBlock> {
132         if unlikely(unsafe { !__PROCESS_MANAGEMENT_INIT_DONE }) {
133             kerror!("unsafe__PROCESS_MANAGEMENT_INIT_DONE == false");
134             loop {
135                 spin_loop();
136             }
137         }
138         return ProcessControlBlock::arch_current_pcb();
139     }
140 
141     /// 获取当前进程的pid
142     ///
143     /// 如果进程管理器未初始化完成,那么返回0
144     pub fn current_pid() -> Pid {
145         if unlikely(unsafe { !__PROCESS_MANAGEMENT_INIT_DONE }) {
146             return Pid(0);
147         }
148 
149         return ProcessManager::current_pcb().pid();
150     }
151 
152     /// 增加当前进程的锁持有计数
153     #[inline(always)]
154     pub fn preempt_disable() {
155         if likely(unsafe { __PROCESS_MANAGEMENT_INIT_DONE }) {
156             ProcessManager::current_pcb().preempt_disable();
157         }
158     }
159 
160     /// 减少当前进程的锁持有计数
161     #[inline(always)]
162     pub fn preempt_enable() {
163         if likely(unsafe { __PROCESS_MANAGEMENT_INIT_DONE }) {
164             ProcessManager::current_pcb().preempt_enable();
165         }
166     }
167 
168     /// 根据pid获取进程的pcb
169     ///
170     /// ## 参数
171     ///
172     /// - `pid` : 进程的pid
173     ///
174     /// ## 返回值
175     ///
176     /// 如果找到了对应的进程,那么返回该进程的pcb,否则返回None
177     pub fn find(pid: Pid) -> Option<Arc<ProcessControlBlock>> {
178         return ALL_PROCESS.lock_irqsave().as_ref()?.get(&pid).cloned();
179     }
180 
181     /// 向系统中添加一个进程的pcb
182     ///
183     /// ## 参数
184     ///
185     /// - `pcb` : 进程的pcb
186     ///
187     /// ## 返回值
188     ///
189     /// 无
190     pub fn add_pcb(pcb: Arc<ProcessControlBlock>) {
191         ALL_PROCESS
192             .lock_irqsave()
193             .as_mut()
194             .unwrap()
195             .insert(pcb.pid(), pcb.clone());
196     }
197 
198     /// 唤醒一个进程
199     pub fn wakeup(pcb: &Arc<ProcessControlBlock>) -> Result<(), SystemError> {
200         let _guard = unsafe { CurrentIrqArch::save_and_disable_irq() };
201         let state = pcb.sched_info().inner_lock_read_irqsave().state();
202         if state.is_blocked() {
203             let mut writer = pcb.sched_info().inner_lock_write_irqsave();
204             let state = writer.state();
205             if state.is_blocked() {
206                 writer.set_state(ProcessState::Runnable);
207                 // avoid deadlock
208                 drop(writer);
209 
210                 sched_enqueue(pcb.clone(), true);
211                 return Ok(());
212             } else if state.is_exited() {
213                 return Err(SystemError::EINVAL);
214             } else {
215                 return Ok(());
216             }
217         } else if state.is_exited() {
218             return Err(SystemError::EINVAL);
219         } else {
220             return Ok(());
221         }
222     }
223 
224     /// 唤醒暂停的进程
225     pub fn wakeup_stop(pcb: &Arc<ProcessControlBlock>) -> Result<(), SystemError> {
226         let _guard = unsafe { CurrentIrqArch::save_and_disable_irq() };
227         let state = pcb.sched_info().inner_lock_read_irqsave().state();
228         if let ProcessState::Stopped = state {
229             let mut writer = pcb.sched_info().inner_lock_write_irqsave();
230             let state = writer.state();
231             if let ProcessState::Stopped = state {
232                 writer.set_state(ProcessState::Runnable);
233                 // avoid deadlock
234                 drop(writer);
235 
236                 sched_enqueue(pcb.clone(), true);
237                 return Ok(());
238             } else if state.is_runnable() {
239                 return Ok(());
240             } else {
241                 return Err(SystemError::EINVAL);
242             }
243         } else if state.is_runnable() {
244             return Ok(());
245         } else {
246             return Err(SystemError::EINVAL);
247         }
248     }
249 
250     /// 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
251     ///
252     /// ## 注意
253     ///
254     /// - 进入当前函数之前,不能持有sched_info的锁
255     /// - 进入当前函数之前,必须关闭中断
256     /// - 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
257     pub fn mark_sleep(interruptable: bool) -> Result<(), SystemError> {
258         assert_eq!(
259             CurrentIrqArch::is_irq_enabled(),
260             false,
261             "interrupt must be disabled before enter ProcessManager::mark_sleep()"
262         );
263 
264         let pcb = ProcessManager::current_pcb();
265         let mut writer = pcb.sched_info().inner_lock_write_irqsave();
266         if !matches!(writer.state(), ProcessState::Exited(_)) {
267             writer.set_state(ProcessState::Blocked(interruptable));
268             pcb.flags().insert(ProcessFlags::NEED_SCHEDULE);
269             drop(writer);
270 
271             return Ok(());
272         }
273         return Err(SystemError::EINTR);
274     }
275 
276     /// 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
277     ///
278     /// ## 注意
279     ///
280     /// - 进入当前函数之前,不能持有sched_info的锁
281     /// - 进入当前函数之前,必须关闭中断
282     pub fn mark_stop() -> Result<(), SystemError> {
283         assert_eq!(
284             CurrentIrqArch::is_irq_enabled(),
285             false,
286             "interrupt must be disabled before enter ProcessManager::mark_stop()"
287         );
288 
289         let pcb = ProcessManager::current_pcb();
290         let mut writer = pcb.sched_info().inner_lock_write_irqsave();
291         if !matches!(writer.state(), ProcessState::Exited(_)) {
292             writer.set_state(ProcessState::Stopped);
293             pcb.flags().insert(ProcessFlags::NEED_SCHEDULE);
294             drop(writer);
295 
296             return Ok(());
297         }
298         return Err(SystemError::EINTR);
299     }
300     /// 当子进程退出后向父进程发送通知
301     fn exit_notify() {
302         let current = ProcessManager::current_pcb();
303         // 让INIT进程收养所有子进程
304         if current.pid() != Pid(1) {
305             unsafe {
306                 current
307                     .adopt_childen()
308                     .unwrap_or_else(|e| panic!("adopte_childen failed: error: {e:?}"))
309             };
310             let r = current.parent_pcb.read().upgrade();
311             if r.is_none() {
312                 return;
313             }
314             let parent_pcb = r.unwrap();
315             let r = Syscall::kill(parent_pcb.pid(), Signal::SIGCHLD as i32);
316             if r.is_err() {
317                 kwarn!(
318                     "failed to send kill signal to {:?}'s parent pcb {:?}",
319                     current.pid(),
320                     parent_pcb.pid()
321                 );
322             }
323             // todo: 这里需要向父进程发送SIGCHLD信号
324             // todo: 这里还需要根据线程组的信息,决定信号的发送
325         }
326     }
327 
328     /// 退出当前进程
329     ///
330     /// ## 参数
331     ///
332     /// - `exit_code` : 进程的退出码
333     pub fn exit(exit_code: usize) -> ! {
334         // 关中断
335         unsafe { CurrentIrqArch::interrupt_disable() };
336         let pcb = ProcessManager::current_pcb();
337         pcb.sched_info
338             .inner_lock_write_irqsave()
339             .set_state(ProcessState::Exited(exit_code));
340         pcb.wait_queue.wakeup(Some(ProcessState::Blocked(true)));
341 
342         // 进行进程退出后的工作
343         let thread = pcb.thread.write();
344         if let Some(addr) = thread.set_child_tid {
345             unsafe { clear_user(addr, core::mem::size_of::<i32>()).expect("clear tid failed") };
346         }
347 
348         if let Some(addr) = thread.clear_child_tid {
349             if Arc::strong_count(&pcb.basic().user_vm().expect("User VM Not found")) > 1 {
350                 let _ =
351                     Futex::futex_wake(addr, FutexFlag::FLAGS_MATCH_NONE, 1, FUTEX_BITSET_MATCH_ANY);
352             }
353             unsafe { clear_user(addr, core::mem::size_of::<i32>()).expect("clear tid failed") };
354         }
355 
356         // 如果是vfork出来的进程,则需要处理completion
357         if thread.vfork_done.is_some() {
358             thread.vfork_done.as_ref().unwrap().complete_all();
359         }
360         drop(thread);
361         unsafe { pcb.basic_mut().set_user_vm(None) };
362         drop(pcb);
363         ProcessManager::exit_notify();
364         unsafe { CurrentIrqArch::interrupt_enable() };
365 
366         sched();
367         loop {}
368     }
369 
370     pub unsafe fn release(pid: Pid) {
371         let pcb = ProcessManager::find(pid);
372         if pcb.is_some() {
373             // let pcb = pcb.unwrap();
374             // 判断该pcb是否在全局没有任何引用
375             // 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。
376             //          因此目前暂时注释掉,使得能跑
377             // if Arc::strong_count(&pcb) <= 2 {
378             //     drop(pcb);
379             //     ALL_PROCESS.lock().as_mut().unwrap().remove(&pid);
380             // } else {
381             //     // 如果不为1就panic
382             //     let msg = format!("pcb '{:?}' is still referenced, strong count={}",pcb.pid(),  Arc::strong_count(&pcb));
383             //     kerror!("{}", msg);
384             //     panic!()
385             // }
386 
387             ALL_PROCESS.lock_irqsave().as_mut().unwrap().remove(&pid);
388         }
389     }
390 
391     /// 上下文切换完成后的钩子函数
392     unsafe fn switch_finish_hook() {
393         // kdebug!("switch_finish_hook");
394         let prev_pcb = SWITCH_RESULT
395             .as_mut()
396             .unwrap()
397             .get_mut()
398             .prev_pcb
399             .take()
400             .expect("prev_pcb is None");
401         let next_pcb = SWITCH_RESULT
402             .as_mut()
403             .unwrap()
404             .get_mut()
405             .next_pcb
406             .take()
407             .expect("next_pcb is None");
408 
409         // 由于进程切换前使用了SpinLockGuard::leak(),所以这里需要手动释放锁
410         prev_pcb.arch_info.force_unlock();
411         next_pcb.arch_info.force_unlock();
412     }
413 
414     /// 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
415     ///
416     /// ## 参数
417     ///
418     /// - `pcb` : 进程的pcb
419     #[allow(dead_code)]
420     pub fn kick(pcb: &Arc<ProcessControlBlock>) {
421         ProcessManager::current_pcb().preempt_disable();
422         let cpu_id = pcb.sched_info().on_cpu();
423 
424         if let Some(cpu_id) = cpu_id {
425             let cpu_id = cpu_id;
426 
427             if pcb.pid() == CPU_EXECUTING.get(cpu_id) {
428                 kick_cpu(cpu_id).expect("ProcessManager::kick(): Failed to kick cpu");
429             }
430         }
431 
432         ProcessManager::current_pcb().preempt_enable();
433     }
434 }
435 
436 /// 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
437 #[cfg(target_arch = "x86_64")]
438 pub unsafe extern "sysv64" fn switch_finish_hook() {
439     ProcessManager::switch_finish_hook();
440 }
441 #[cfg(target_arch = "riscv64")]
442 pub unsafe extern "C" fn switch_finish_hook() {
443     ProcessManager::switch_finish_hook();
444 }
445 
446 int_like!(Pid, AtomicPid, usize, AtomicUsize);
447 
448 impl Hash for Pid {
449     fn hash<H: Hasher>(&self, state: &mut H) {
450         self.0.hash(state);
451     }
452 }
453 
454 impl Pid {
455     pub fn to_string(&self) -> String {
456         self.0.to_string()
457     }
458 }
459 
460 #[derive(Debug, Clone, Copy, PartialEq, Eq)]
461 pub enum ProcessState {
462     /// The process is running on a CPU or in a run queue.
463     Runnable,
464     /// The process is waiting for an event to occur.
465     /// 其中的bool表示该等待过程是否可以被打断。
466     /// - 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。
467     /// - 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。
468     Blocked(bool),
469     /// 进程被信号终止
470     Stopped,
471     /// 进程已经退出,usize表示进程的退出码
472     Exited(usize),
473 }
474 
475 #[allow(dead_code)]
476 impl ProcessState {
477     #[inline(always)]
478     pub fn is_runnable(&self) -> bool {
479         return matches!(self, ProcessState::Runnable);
480     }
481 
482     #[inline(always)]
483     pub fn is_blocked(&self) -> bool {
484         return matches!(self, ProcessState::Blocked(_));
485     }
486 
487     #[inline(always)]
488     pub fn is_blocked_interruptable(&self) -> bool {
489         return matches!(self, ProcessState::Blocked(true));
490     }
491 
492     /// Returns `true` if the process state is [`Exited`].
493     #[inline(always)]
494     pub fn is_exited(&self) -> bool {
495         return matches!(self, ProcessState::Exited(_));
496     }
497 
498     /// Returns `true` if the process state is [`Stopped`].
499     ///
500     /// [`Stopped`]: ProcessState::Stopped
501     #[inline(always)]
502     pub fn is_stopped(&self) -> bool {
503         matches!(self, ProcessState::Stopped)
504     }
505 
506     /// Returns exit code if the process state is [`Exited`].
507     #[inline(always)]
508     pub fn exit_code(&self) -> Option<usize> {
509         match self {
510             ProcessState::Exited(code) => Some(*code),
511             _ => None,
512         }
513     }
514 }
515 
516 bitflags! {
517     /// pcb的标志位
518     pub struct ProcessFlags: usize {
519         /// 当前pcb表示一个内核线程
520         const KTHREAD = 1 << 0;
521         /// 当前进程需要被调度
522         const NEED_SCHEDULE = 1 << 1;
523         /// 进程由于vfork而与父进程存在资源共享
524         const VFORK = 1 << 2;
525         /// 进程不可被冻结
526         const NOFREEZE = 1 << 3;
527         /// 进程正在退出
528         const EXITING = 1 << 4;
529         /// 进程由于接收到终止信号唤醒
530         const WAKEKILL = 1 << 5;
531         /// 进程由于接收到信号而退出.(Killed by a signal)
532         const SIGNALED = 1 << 6;
533         /// 进程需要迁移到其他cpu上
534         const NEED_MIGRATE = 1 << 7;
535         /// 随机化的虚拟地址空间,主要用于动态链接器的加载
536         const RANDOMIZE = 1 << 8;
537     }
538 }
539 
540 #[derive(Debug)]
541 pub struct ProcessControlBlock {
542     /// 当前进程的pid
543     pid: Pid,
544     /// 当前进程的线程组id(这个值在同一个线程组内永远不变)
545     tgid: Pid,
546 
547     basic: RwLock<ProcessBasicInfo>,
548     /// 当前进程的自旋锁持有计数
549     preempt_count: AtomicUsize,
550 
551     flags: LockFreeFlags<ProcessFlags>,
552     worker_private: SpinLock<Option<WorkerPrivate>>,
553     /// 进程的内核栈
554     kernel_stack: RwLock<KernelStack>,
555 
556     /// 系统调用栈
557     syscall_stack: RwLock<KernelStack>,
558 
559     /// 与调度相关的信息
560     sched_info: ProcessSchedulerInfo,
561     /// 与处理器架构相关的信息
562     arch_info: SpinLock<ArchPCBInfo>,
563     /// 与信号处理相关的信息(似乎可以是无锁的)
564     sig_info: RwLock<ProcessSignalInfo>,
565     /// 信号处理结构体
566     sig_struct: SpinLock<SignalStruct>,
567     /// 退出信号S
568     exit_signal: AtomicSignal,
569 
570     /// 父进程指针
571     parent_pcb: RwLock<Weak<ProcessControlBlock>>,
572     /// 真实父进程指针
573     real_parent_pcb: RwLock<Weak<ProcessControlBlock>>,
574 
575     /// 子进程链表
576     children: RwLock<Vec<Pid>>,
577 
578     /// 等待队列
579     wait_queue: WaitQueue,
580 
581     /// 线程信息
582     thread: RwLock<ThreadInfo>,
583 }
584 
585 impl ProcessControlBlock {
586     /// Generate a new pcb.
587     ///
588     /// ## 参数
589     ///
590     /// - `name` : 进程的名字
591     /// - `kstack` : 进程的内核栈
592     ///
593     /// ## 返回值
594     ///
595     /// 返回一个新的pcb
596     pub fn new(name: String, kstack: KernelStack) -> Arc<Self> {
597         return Self::do_create_pcb(name, kstack, false);
598     }
599 
600     /// 创建一个新的idle进程
601     ///
602     /// 请注意,这个函数只能在进程管理初始化的时候调用。
603     pub fn new_idle(cpu_id: u32, kstack: KernelStack) -> Arc<Self> {
604         let name = format!("idle-{}", cpu_id);
605         return Self::do_create_pcb(name, kstack, true);
606     }
607 
608     #[inline(never)]
609     fn do_create_pcb(name: String, kstack: KernelStack, is_idle: bool) -> Arc<Self> {
610         let (pid, ppid, cwd) = if is_idle {
611             (Pid(0), Pid(0), "/".to_string())
612         } else {
613             let ppid = ProcessManager::current_pcb().pid();
614             let cwd = ProcessManager::current_pcb().basic().cwd();
615             (Self::generate_pid(), ppid, cwd)
616         };
617 
618         let basic_info = ProcessBasicInfo::new(Pid(0), ppid, name, cwd, None);
619         let preempt_count = AtomicUsize::new(0);
620         let flags = unsafe { LockFreeFlags::new(ProcessFlags::empty()) };
621 
622         let sched_info = ProcessSchedulerInfo::new(None);
623         let arch_info = SpinLock::new(ArchPCBInfo::new(&kstack));
624 
625         let ppcb: Weak<ProcessControlBlock> = ProcessManager::find(ppid)
626             .map(|p| Arc::downgrade(&p))
627             .unwrap_or_else(|| Weak::new());
628 
629         let pcb = Self {
630             pid,
631             tgid: pid,
632             basic: basic_info,
633             preempt_count,
634             flags,
635             kernel_stack: RwLock::new(kstack),
636             syscall_stack: RwLock::new(KernelStack::new().unwrap()),
637             worker_private: SpinLock::new(None),
638             sched_info,
639             arch_info,
640             sig_info: RwLock::new(ProcessSignalInfo::default()),
641             sig_struct: SpinLock::new(SignalStruct::new()),
642             exit_signal: AtomicSignal::new(Signal::SIGCHLD),
643             parent_pcb: RwLock::new(ppcb.clone()),
644             real_parent_pcb: RwLock::new(ppcb),
645             children: RwLock::new(Vec::new()),
646             wait_queue: WaitQueue::INIT,
647             thread: RwLock::new(ThreadInfo::new()),
648         };
649 
650         // 初始化系统调用栈
651         #[cfg(target_arch = "x86_64")]
652         pcb.arch_info
653             .lock()
654             .init_syscall_stack(&pcb.syscall_stack.read());
655 
656         let pcb = Arc::new(pcb);
657 
658         // 设置进程的arc指针到内核栈和系统调用栈的最低地址处
659         unsafe {
660             pcb.kernel_stack
661                 .write()
662                 .set_pcb(Arc::downgrade(&pcb))
663                 .unwrap();
664 
665             pcb.syscall_stack
666                 .write()
667                 .set_pcb(Arc::downgrade(&pcb))
668                 .unwrap()
669         };
670 
671         // 将当前pcb加入父进程的子进程哈希表中
672         if pcb.pid() > Pid(1) {
673             if let Some(ppcb_arc) = pcb.parent_pcb.read().upgrade() {
674                 let mut children = ppcb_arc.children.write_irqsave();
675                 children.push(pcb.pid());
676             } else {
677                 panic!("parent pcb is None");
678             }
679         }
680 
681         return pcb;
682     }
683 
684     /// 生成一个新的pid
685     #[inline(always)]
686     fn generate_pid() -> Pid {
687         static NEXT_PID: AtomicPid = AtomicPid::new(Pid(1));
688         return NEXT_PID.fetch_add(Pid(1), Ordering::SeqCst);
689     }
690 
691     /// 返回当前进程的锁持有计数
692     #[inline(always)]
693     pub fn preempt_count(&self) -> usize {
694         return self.preempt_count.load(Ordering::SeqCst);
695     }
696 
697     /// 增加当前进程的锁持有计数
698     #[inline(always)]
699     pub fn preempt_disable(&self) {
700         self.preempt_count.fetch_add(1, Ordering::SeqCst);
701     }
702 
703     /// 减少当前进程的锁持有计数
704     #[inline(always)]
705     pub fn preempt_enable(&self) {
706         self.preempt_count.fetch_sub(1, Ordering::SeqCst);
707     }
708 
709     #[inline(always)]
710     pub unsafe fn set_preempt_count(&self, count: usize) {
711         self.preempt_count.store(count, Ordering::SeqCst);
712     }
713 
714     #[inline(always)]
715     pub fn flags(&self) -> &mut ProcessFlags {
716         return self.flags.get_mut();
717     }
718 
719     /// 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
720     /// 否则会导致死锁
721     #[inline(always)]
722     pub fn basic(&self) -> RwLockReadGuard<ProcessBasicInfo> {
723         return self.basic.read();
724     }
725 
726     #[inline(always)]
727     pub fn set_name(&self, name: String) {
728         self.basic.write().set_name(name);
729     }
730 
731     #[inline(always)]
732     pub fn basic_mut(&self) -> RwLockWriteGuard<ProcessBasicInfo> {
733         return self.basic.write_irqsave();
734     }
735 
736     /// # 获取arch info的锁,同时关闭中断
737     #[inline(always)]
738     pub fn arch_info_irqsave(&self) -> SpinLockGuard<ArchPCBInfo> {
739         return self.arch_info.lock_irqsave();
740     }
741 
742     /// # 获取arch info的锁,但是不关闭中断
743     ///
744     /// 由于arch info在进程切换的时候会使用到,
745     /// 因此在中断上下文外,获取arch info 而不irqsave是不安全的.
746     ///
747     /// 只能在以下情况下使用这个函数:
748     /// - 在中断上下文中(中断已经禁用),获取arch info的锁。
749     /// - 刚刚创建新的pcb
750     #[inline(always)]
751     pub unsafe fn arch_info(&self) -> SpinLockGuard<ArchPCBInfo> {
752         return self.arch_info.lock();
753     }
754 
755     #[inline(always)]
756     pub fn kernel_stack(&self) -> RwLockReadGuard<KernelStack> {
757         return self.kernel_stack.read();
758     }
759 
760     #[inline(always)]
761     #[allow(dead_code)]
762     pub fn kernel_stack_mut(&self) -> RwLockWriteGuard<KernelStack> {
763         return self.kernel_stack.write();
764     }
765 
766     #[inline(always)]
767     pub fn sched_info(&self) -> &ProcessSchedulerInfo {
768         return &self.sched_info;
769     }
770 
771     #[inline(always)]
772     pub fn worker_private(&self) -> SpinLockGuard<Option<WorkerPrivate>> {
773         return self.worker_private.lock();
774     }
775 
776     #[inline(always)]
777     pub fn pid(&self) -> Pid {
778         return self.pid;
779     }
780 
781     #[inline(always)]
782     pub fn tgid(&self) -> Pid {
783         return self.tgid;
784     }
785 
786     /// 获取文件描述符表的Arc指针
787     #[inline(always)]
788     pub fn fd_table(&self) -> Arc<RwLock<FileDescriptorVec>> {
789         return self.basic.read().fd_table().unwrap();
790     }
791 
792     /// 根据文件描述符序号,获取socket对象的Arc指针
793     ///
794     /// ## 参数
795     ///
796     /// - `fd` 文件描述符序号
797     ///
798     /// ## 返回值
799     ///
800     /// 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
801     pub fn get_socket(&self, fd: i32) -> Option<Arc<SocketInode>> {
802         let binding = ProcessManager::current_pcb().fd_table();
803         let fd_table_guard = binding.read();
804 
805         let f = fd_table_guard.get_file_by_fd(fd)?;
806         drop(fd_table_guard);
807 
808         let guard = f.lock();
809         if guard.file_type() != FileType::Socket {
810             return None;
811         }
812         let socket: Arc<SocketInode> = guard
813             .inode()
814             .downcast_arc::<SocketInode>()
815             .expect("Not a socket inode");
816         return Some(socket);
817     }
818 
819     /// 当前进程退出时,让初始进程收养所有子进程
820     unsafe fn adopt_childen(&self) -> Result<(), SystemError> {
821         match ProcessManager::find(Pid(1)) {
822             Some(init_pcb) => {
823                 let childen_guard = self.children.write();
824                 let mut init_childen_guard = init_pcb.children.write();
825 
826                 childen_guard.iter().for_each(|pid| {
827                     init_childen_guard.push(*pid);
828                 });
829 
830                 return Ok(());
831             }
832             _ => Err(SystemError::ECHILD),
833         }
834     }
835 
836     /// 生成进程的名字
837     pub fn generate_name(program_path: &str, args: &Vec<String>) -> String {
838         let mut name = program_path.to_string();
839         for arg in args {
840             name.push(' ');
841             name.push_str(arg);
842         }
843         return name;
844     }
845 
846     pub fn sig_info(&self) -> RwLockReadGuard<ProcessSignalInfo> {
847         self.sig_info.read()
848     }
849 
850     pub fn sig_info_irqsave(&self) -> RwLockReadGuard<ProcessSignalInfo> {
851         self.sig_info.read_irqsave()
852     }
853 
854     pub fn try_siginfo(&self, times: u8) -> Option<RwLockReadGuard<ProcessSignalInfo>> {
855         for _ in 0..times {
856             if let Some(r) = self.sig_info.try_read() {
857                 return Some(r);
858             }
859         }
860 
861         return None;
862     }
863 
864     pub fn sig_info_mut(&self) -> RwLockWriteGuard<ProcessSignalInfo> {
865         self.sig_info.write_irqsave()
866     }
867 
868     pub fn try_siginfo_mut(&self, times: u8) -> Option<RwLockWriteGuard<ProcessSignalInfo>> {
869         for _ in 0..times {
870             if let Some(r) = self.sig_info.try_write() {
871                 return Some(r);
872             }
873         }
874 
875         return None;
876     }
877 
878     pub fn sig_struct(&self) -> SpinLockGuard<SignalStruct> {
879         self.sig_struct.lock()
880     }
881 
882     pub fn try_sig_struct_irq(&self, times: u8) -> Option<SpinLockGuard<SignalStruct>> {
883         for _ in 0..times {
884             if let Ok(r) = self.sig_struct.try_lock_irqsave() {
885                 return Some(r);
886             }
887         }
888 
889         return None;
890     }
891 
892     pub fn sig_struct_irqsave(&self) -> SpinLockGuard<SignalStruct> {
893         self.sig_struct.lock_irqsave()
894     }
895 }
896 
897 impl Drop for ProcessControlBlock {
898     fn drop(&mut self) {
899         // 在ProcFS中,解除进程的注册
900         procfs_unregister_pid(self.pid())
901             .unwrap_or_else(|e| panic!("procfs_unregister_pid failed: error: {e:?}"));
902 
903         if let Some(ppcb) = self.parent_pcb.read().upgrade() {
904             ppcb.children.write().retain(|pid| *pid != self.pid());
905         }
906     }
907 }
908 
909 /// 线程信息
910 #[derive(Debug)]
911 pub struct ThreadInfo {
912     // 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
913     clear_child_tid: Option<VirtAddr>,
914     set_child_tid: Option<VirtAddr>,
915 
916     vfork_done: Option<Arc<Completion>>,
917     /// 线程组的组长
918     group_leader: Weak<ProcessControlBlock>,
919 }
920 
921 impl ThreadInfo {
922     pub fn new() -> Self {
923         Self {
924             clear_child_tid: None,
925             set_child_tid: None,
926             vfork_done: None,
927             group_leader: Weak::default(),
928         }
929     }
930 
931     pub fn group_leader(&self) -> Option<Arc<ProcessControlBlock>> {
932         return self.group_leader.upgrade();
933     }
934 }
935 
936 /// 进程的基本信息
937 ///
938 /// 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。
939 #[derive(Debug)]
940 pub struct ProcessBasicInfo {
941     /// 当前进程的进程组id
942     pgid: Pid,
943     /// 当前进程的父进程的pid
944     ppid: Pid,
945     /// 进程的名字
946     name: String,
947 
948     /// 当前进程的工作目录
949     cwd: String,
950 
951     /// 用户地址空间
952     user_vm: Option<Arc<AddressSpace>>,
953 
954     /// 文件描述符表
955     fd_table: Option<Arc<RwLock<FileDescriptorVec>>>,
956 }
957 
958 impl ProcessBasicInfo {
959     #[inline(never)]
960     pub fn new(
961         pgid: Pid,
962         ppid: Pid,
963         name: String,
964         cwd: String,
965         user_vm: Option<Arc<AddressSpace>>,
966     ) -> RwLock<Self> {
967         let fd_table = Arc::new(RwLock::new(FileDescriptorVec::new()));
968         return RwLock::new(Self {
969             pgid,
970             ppid,
971             name,
972             cwd,
973             user_vm,
974             fd_table: Some(fd_table),
975         });
976     }
977 
978     pub fn pgid(&self) -> Pid {
979         return self.pgid;
980     }
981 
982     pub fn ppid(&self) -> Pid {
983         return self.ppid;
984     }
985 
986     pub fn name(&self) -> &str {
987         return &self.name;
988     }
989 
990     pub fn set_name(&mut self, name: String) {
991         self.name = name;
992     }
993 
994     pub fn cwd(&self) -> String {
995         return self.cwd.clone();
996     }
997     pub fn set_cwd(&mut self, path: String) {
998         return self.cwd = path;
999     }
1000 
1001     pub fn user_vm(&self) -> Option<Arc<AddressSpace>> {
1002         return self.user_vm.clone();
1003     }
1004 
1005     pub unsafe fn set_user_vm(&mut self, user_vm: Option<Arc<AddressSpace>>) {
1006         self.user_vm = user_vm;
1007     }
1008 
1009     pub fn fd_table(&self) -> Option<Arc<RwLock<FileDescriptorVec>>> {
1010         return self.fd_table.clone();
1011     }
1012 
1013     pub fn set_fd_table(&mut self, fd_table: Option<Arc<RwLock<FileDescriptorVec>>>) {
1014         self.fd_table = fd_table;
1015     }
1016 }
1017 
1018 #[derive(Debug)]
1019 pub struct ProcessSchedulerInfo {
1020     /// 当前进程所在的cpu
1021     on_cpu: AtomicI32,
1022     /// 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),
1023     /// 该字段存储要被迁移到的目标处理器核心号
1024     migrate_to: AtomicI32,
1025     inner_locked: RwLock<InnerSchedInfo>,
1026     /// 进程的调度优先级
1027     priority: SchedPriority,
1028     /// 当前进程的虚拟运行时间
1029     virtual_runtime: AtomicIsize,
1030     /// 由实时调度器管理的时间片
1031     rt_time_slice: AtomicIsize,
1032 }
1033 
1034 #[derive(Debug)]
1035 pub struct InnerSchedInfo {
1036     /// 当前进程的状态
1037     state: ProcessState,
1038     /// 进程的调度策略
1039     sched_policy: SchedPolicy,
1040 }
1041 
1042 impl InnerSchedInfo {
1043     pub fn state(&self) -> ProcessState {
1044         return self.state;
1045     }
1046 
1047     pub fn set_state(&mut self, state: ProcessState) {
1048         self.state = state;
1049     }
1050 
1051     pub fn policy(&self) -> SchedPolicy {
1052         return self.sched_policy;
1053     }
1054 }
1055 
1056 impl ProcessSchedulerInfo {
1057     #[inline(never)]
1058     pub fn new(on_cpu: Option<u32>) -> Self {
1059         let cpu_id = match on_cpu {
1060             Some(cpu_id) => cpu_id as i32,
1061             None => -1,
1062         };
1063         return Self {
1064             on_cpu: AtomicI32::new(cpu_id),
1065             migrate_to: AtomicI32::new(-1),
1066             inner_locked: RwLock::new(InnerSchedInfo {
1067                 state: ProcessState::Blocked(false),
1068                 sched_policy: SchedPolicy::CFS,
1069             }),
1070             virtual_runtime: AtomicIsize::new(0),
1071             rt_time_slice: AtomicIsize::new(0),
1072             priority: SchedPriority::new(100).unwrap(),
1073         };
1074     }
1075 
1076     pub fn on_cpu(&self) -> Option<u32> {
1077         let on_cpu = self.on_cpu.load(Ordering::SeqCst);
1078         if on_cpu == -1 {
1079             return None;
1080         } else {
1081             return Some(on_cpu as u32);
1082         }
1083     }
1084 
1085     pub fn set_on_cpu(&self, on_cpu: Option<u32>) {
1086         if let Some(cpu_id) = on_cpu {
1087             self.on_cpu.store(cpu_id as i32, Ordering::SeqCst);
1088         } else {
1089             self.on_cpu.store(-1, Ordering::SeqCst);
1090         }
1091     }
1092 
1093     pub fn migrate_to(&self) -> Option<u32> {
1094         let migrate_to = self.migrate_to.load(Ordering::SeqCst);
1095         if migrate_to == -1 {
1096             return None;
1097         } else {
1098             return Some(migrate_to as u32);
1099         }
1100     }
1101 
1102     pub fn set_migrate_to(&self, migrate_to: Option<u32>) {
1103         if let Some(data) = migrate_to {
1104             self.migrate_to.store(data as i32, Ordering::SeqCst);
1105         } else {
1106             self.migrate_to.store(-1, Ordering::SeqCst)
1107         }
1108     }
1109 
1110     pub fn inner_lock_write_irqsave(&self) -> RwLockWriteGuard<InnerSchedInfo> {
1111         return self.inner_locked.write_irqsave();
1112     }
1113 
1114     pub fn inner_lock_read_irqsave(&self) -> RwLockReadGuard<InnerSchedInfo> {
1115         return self.inner_locked.read_irqsave();
1116     }
1117 
1118     pub fn inner_lock_try_read_irqsave(
1119         &self,
1120         times: u8,
1121     ) -> Option<RwLockReadGuard<InnerSchedInfo>> {
1122         for _ in 0..times {
1123             if let Some(r) = self.inner_locked.try_read_irqsave() {
1124                 return Some(r);
1125             }
1126         }
1127 
1128         return None;
1129     }
1130 
1131     pub fn inner_lock_try_upgradable_read_irqsave(
1132         &self,
1133         times: u8,
1134     ) -> Option<RwLockUpgradableGuard<InnerSchedInfo>> {
1135         for _ in 0..times {
1136             if let Some(r) = self.inner_locked.try_upgradeable_read_irqsave() {
1137                 return Some(r);
1138             }
1139         }
1140 
1141         return None;
1142     }
1143 
1144     pub fn virtual_runtime(&self) -> isize {
1145         return self.virtual_runtime.load(Ordering::SeqCst);
1146     }
1147 
1148     pub fn set_virtual_runtime(&self, virtual_runtime: isize) {
1149         self.virtual_runtime
1150             .store(virtual_runtime, Ordering::SeqCst);
1151     }
1152     pub fn increase_virtual_runtime(&self, delta: isize) {
1153         self.virtual_runtime.fetch_add(delta, Ordering::SeqCst);
1154     }
1155 
1156     pub fn rt_time_slice(&self) -> isize {
1157         return self.rt_time_slice.load(Ordering::SeqCst);
1158     }
1159 
1160     pub fn set_rt_time_slice(&self, rt_time_slice: isize) {
1161         self.rt_time_slice.store(rt_time_slice, Ordering::SeqCst);
1162     }
1163 
1164     pub fn increase_rt_time_slice(&self, delta: isize) {
1165         self.rt_time_slice.fetch_add(delta, Ordering::SeqCst);
1166     }
1167 
1168     pub fn priority(&self) -> SchedPriority {
1169         return self.priority;
1170     }
1171 }
1172 
1173 #[derive(Debug, Clone)]
1174 pub struct KernelStack {
1175     stack: Option<AlignedBox<[u8; KernelStack::SIZE], { KernelStack::ALIGN }>>,
1176     /// 标记该内核栈是否可以被释放
1177     can_be_freed: bool,
1178 }
1179 
1180 impl KernelStack {
1181     pub const SIZE: usize = 0x4000;
1182     pub const ALIGN: usize = 0x4000;
1183 
1184     pub fn new() -> Result<Self, SystemError> {
1185         return Ok(Self {
1186             stack: Some(
1187                 AlignedBox::<[u8; KernelStack::SIZE], { KernelStack::ALIGN }>::new_zeroed()?,
1188             ),
1189             can_be_freed: true,
1190         });
1191     }
1192 
1193     /// 根据已有的空间,构造一个内核栈结构体
1194     ///
1195     /// 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!
1196     pub unsafe fn from_existed(base: VirtAddr) -> Result<Self, SystemError> {
1197         if base.is_null() || base.check_aligned(Self::ALIGN) == false {
1198             return Err(SystemError::EFAULT);
1199         }
1200 
1201         return Ok(Self {
1202             stack: Some(
1203                 AlignedBox::<[u8; KernelStack::SIZE], { KernelStack::ALIGN }>::new_unchecked(
1204                     base.data() as *mut [u8; KernelStack::SIZE],
1205                 ),
1206             ),
1207             can_be_freed: false,
1208         });
1209     }
1210 
1211     /// 返回内核栈的起始虚拟地址(低地址)
1212     pub fn start_address(&self) -> VirtAddr {
1213         return VirtAddr::new(self.stack.as_ref().unwrap().as_ptr() as usize);
1214     }
1215 
1216     /// 返回内核栈的结束虚拟地址(高地址)(不包含该地址)
1217     pub fn stack_max_address(&self) -> VirtAddr {
1218         return VirtAddr::new(self.stack.as_ref().unwrap().as_ptr() as usize + Self::SIZE);
1219     }
1220 
1221     pub unsafe fn set_pcb(&mut self, pcb: Weak<ProcessControlBlock>) -> Result<(), SystemError> {
1222         // 将一个Weak<ProcessControlBlock>放到内核栈的最低地址处
1223         let p: *const ProcessControlBlock = Weak::into_raw(pcb);
1224         let stack_bottom_ptr = self.start_address().data() as *mut *const ProcessControlBlock;
1225 
1226         // 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
1227         if unlikely(unsafe { !(*stack_bottom_ptr).is_null() }) {
1228             kerror!("kernel stack bottom is not null: {:p}", *stack_bottom_ptr);
1229             return Err(SystemError::EPERM);
1230         }
1231         // 将pcb的地址放到内核栈的最低地址处
1232         unsafe {
1233             *stack_bottom_ptr = p;
1234         }
1235 
1236         return Ok(());
1237     }
1238 
1239     /// 清除内核栈的pcb指针
1240     ///
1241     /// ## 参数
1242     ///
1243     /// - `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
1244     pub unsafe fn clear_pcb(&mut self, force: bool) {
1245         let stack_bottom_ptr = self.start_address().data() as *mut *const ProcessControlBlock;
1246         if unlikely(unsafe { (*stack_bottom_ptr).is_null() }) {
1247             return;
1248         }
1249 
1250         if !force {
1251             let pcb_ptr: Weak<ProcessControlBlock> = Weak::from_raw(*stack_bottom_ptr);
1252             drop(pcb_ptr);
1253         }
1254 
1255         *stack_bottom_ptr = core::ptr::null();
1256     }
1257 
1258     /// 返回指向当前内核栈pcb的Arc指针
1259     #[allow(dead_code)]
1260     pub unsafe fn pcb(&self) -> Option<Arc<ProcessControlBlock>> {
1261         // 从内核栈的最低地址处取出pcb的地址
1262         let p = self.stack.as_ref().unwrap().as_ptr() as *const *const ProcessControlBlock;
1263         if unlikely(unsafe { (*p).is_null() }) {
1264             return None;
1265         }
1266 
1267         // 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
1268         let weak_wrapper: ManuallyDrop<Weak<ProcessControlBlock>> =
1269             ManuallyDrop::new(Weak::from_raw(*p));
1270 
1271         let new_arc: Arc<ProcessControlBlock> = weak_wrapper.upgrade()?;
1272         return Some(new_arc);
1273     }
1274 }
1275 
1276 impl Drop for KernelStack {
1277     fn drop(&mut self) {
1278         if !self.stack.is_none() {
1279             let ptr = self.stack.as_ref().unwrap().as_ptr() as *const *const ProcessControlBlock;
1280             if unsafe { !(*ptr).is_null() } {
1281                 let pcb_ptr: Weak<ProcessControlBlock> = unsafe { Weak::from_raw(*ptr) };
1282                 drop(pcb_ptr);
1283             }
1284         }
1285         // 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
1286         if !self.can_be_freed {
1287             let bx = self.stack.take();
1288             core::mem::forget(bx);
1289         }
1290     }
1291 }
1292 
1293 pub fn process_init() {
1294     ProcessManager::init();
1295 }
1296 
1297 #[derive(Debug)]
1298 pub struct ProcessSignalInfo {
1299     // 当前进程
1300     sig_block: SigSet,
1301     // sig_pending 中存储当前线程要处理的信号
1302     sig_pending: SigPending,
1303     // sig_shared_pending 中存储当前线程所属进程要处理的信号
1304     sig_shared_pending: SigPending,
1305 }
1306 
1307 impl ProcessSignalInfo {
1308     pub fn sig_block(&self) -> &SigSet {
1309         &self.sig_block
1310     }
1311 
1312     pub fn sig_pending(&self) -> &SigPending {
1313         &self.sig_pending
1314     }
1315 
1316     pub fn sig_pending_mut(&mut self) -> &mut SigPending {
1317         &mut self.sig_pending
1318     }
1319 
1320     pub fn sig_block_mut(&mut self) -> &mut SigSet {
1321         &mut self.sig_block
1322     }
1323 
1324     pub fn sig_shared_pending_mut(&mut self) -> &mut SigPending {
1325         &mut self.sig_shared_pending
1326     }
1327 
1328     pub fn sig_shared_pending(&self) -> &SigPending {
1329         &self.sig_shared_pending
1330     }
1331 
1332     /// 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
1333     ///
1334     /// ## 参数
1335     ///
1336     /// - `sig_mask` 被忽略掉的信号
1337     ///
1338     pub fn dequeue_signal(&mut self, sig_mask: &SigSet) -> (Signal, Option<SigInfo>) {
1339         let res = self.sig_pending.dequeue_signal(sig_mask);
1340         if res.0 != Signal::INVALID {
1341             return res;
1342         } else {
1343             return self.sig_shared_pending.dequeue_signal(sig_mask);
1344         }
1345     }
1346 }
1347 
1348 impl Default for ProcessSignalInfo {
1349     fn default() -> Self {
1350         Self {
1351             sig_block: SigSet::empty(),
1352             sig_pending: SigPending::default(),
1353             sig_shared_pending: SigPending::default(),
1354         }
1355     }
1356 }
1357