xref: /DragonOS/kernel/src/process/fork.rs (revision aa0367d69e15989684109c5b454e85da9ecb1975)
1 use core::{ffi::c_void, ptr::null_mut, sync::atomic::compiler_fence};
2 
3 use alloc::boxed::Box;
4 
5 use crate::{
6     arch::asm::current::current_pcb,
7     include::bindings::bindings::{
8         process_control_block, CLONE_CLEAR_SIGHAND, CLONE_SIGHAND, CLONE_THREAD,
9     },
10     ipc::{
11         signal::{flush_signal_handlers, DEFAULT_SIGACTION},
12         signal_types::{sigaction, sighand_struct, signal_struct, SigQueue},
13     },
14     libs::{
15         atomic::atomic_set,
16         ffi_convert::FFIBind2Rust,
17         refcount::{refcount_inc, RefCount},
18         spinlock::{spin_lock_irqsave, spin_unlock_irqrestore},
19     },
20     syscall::SystemError,
21 };
22 
23 #[no_mangle]
24 pub extern "C" fn process_copy_sighand(clone_flags: u64, pcb: *mut process_control_block) -> i32 {
25     // kdebug!("process_copy_sighand");
26 
27     if (clone_flags & (CLONE_SIGHAND as u64)) != 0 {
28         let r = RefCount::convert_mut(unsafe { &mut (*(current_pcb().sighand)).count }).unwrap();
29         refcount_inc(r);
30     }
31 
32     // 在这里使用Box::leak将动态申请的内存的生命周期转换为static的
33     let mut sig: &mut sighand_struct = Box::leak(Box::new(sighand_struct::default()));
34     if (sig as *mut sighand_struct) == null_mut() {
35         return SystemError::ENOMEM.to_posix_errno();
36     }
37 
38     // 将新的sighand赋值给pcb
39     unsafe {
40         (*pcb).sighand = sig as *mut sighand_struct as usize
41             as *mut crate::include::bindings::bindings::sighand_struct;
42     }
43 
44     // kdebug!("DEFAULT_SIGACTION.sa_flags={}", DEFAULT_SIGACTION.sa_flags);
45 
46     // 拷贝sigaction
47     let mut flags: u64 = 0;
48 
49     spin_lock_irqsave(unsafe { &mut (*current_pcb().sighand).siglock }, &mut flags);
50     compiler_fence(core::sync::atomic::Ordering::SeqCst);
51 
52     for (index, x) in unsafe { (*current_pcb().sighand).action }
53         .iter()
54         .enumerate()
55     {
56         compiler_fence(core::sync::atomic::Ordering::SeqCst);
57         if !(x as *const crate::include::bindings::bindings::sigaction).is_null() {
58             sig.action[index] =
59                 *sigaction::convert_ref(x as *const crate::include::bindings::bindings::sigaction)
60                     .unwrap();
61         } else {
62             sig.action[index] = DEFAULT_SIGACTION;
63         }
64     }
65     compiler_fence(core::sync::atomic::Ordering::SeqCst);
66 
67     spin_unlock_irqrestore(unsafe { &mut (*current_pcb().sighand).siglock }, &flags);
68     compiler_fence(core::sync::atomic::Ordering::SeqCst);
69 
70     // 将信号的处理函数设置为default(除了那些被手动屏蔽的)
71     if (clone_flags & (CLONE_CLEAR_SIGHAND as u64)) != 0 {
72         compiler_fence(core::sync::atomic::Ordering::SeqCst);
73 
74         flush_signal_handlers(pcb, false);
75         compiler_fence(core::sync::atomic::Ordering::SeqCst);
76     }
77     compiler_fence(core::sync::atomic::Ordering::SeqCst);
78 
79     return 0;
80 }
81 
82 #[no_mangle]
83 pub extern "C" fn process_copy_signal(clone_flags: u64, pcb: *mut process_control_block) -> i32 {
84     // kdebug!("process_copy_signal");
85     // 如果克隆的是线程,则不拷贝信号(同一进程的各个线程之间共享信号)
86     if (clone_flags & (CLONE_THREAD as u64)) != 0 {
87         return 0;
88     }
89     let sig: &mut signal_struct = Box::leak(Box::new(signal_struct::default()));
90     if (sig as *mut signal_struct) == null_mut() {
91         return SystemError::ENOMEM.to_posix_errno();
92     }
93     atomic_set(&mut sig.sig_cnt, 1);
94     // 将sig赋值给pcb中的字段
95     unsafe {
96         (*pcb).signal = sig as *mut signal_struct as usize
97             as *mut crate::include::bindings::bindings::signal_struct;
98     }
99 
100     // 创建新的sig_pending->sigqueue
101     unsafe {
102         (*pcb).sig_pending.signal = 0;
103         (*pcb).sig_pending.sigqueue =
104             Box::leak(Box::new(SigQueue::default())) as *mut SigQueue as *mut c_void;
105     }
106     return 0;
107 }
108 
109 #[no_mangle]
110 pub extern "C" fn process_exit_signal(pcb: *mut process_control_block) {
111     // 回收进程的信号结构体
112     unsafe {
113         // 回收sighand
114         let sighand = Box::from_raw((*pcb).sighand as *mut sighand_struct);
115 
116         drop(sighand);
117         (*pcb).sighand = 0 as *mut crate::include::bindings::bindings::sighand_struct;
118 
119         // 回收sigqueue
120         let queue = Box::from_raw((*pcb).sig_pending.sigqueue as *mut SigQueue);
121         drop(queue);
122     }
123 }
124 
125 #[no_mangle]
126 pub extern "C" fn process_exit_sighand(pcb: *mut process_control_block) {
127     // todo: 回收进程的sighand结构体
128     unsafe {
129         let sig = Box::from_raw((*pcb).signal as *mut signal_struct);
130         drop(sig);
131         (*pcb).signal = 0 as *mut crate::include::bindings::bindings::signal_struct;
132     }
133 }
134