修复tty处理信号时错误地将前台进程组置空的问题 & clone时未拷贝父进程tty的问题 (#1043)

* 修复clone时未拷贝父进程tty的问题

* 修复tty处理信号时错误地将前台进程组置空的问题

kernel/src/driver/tty/tty_ldisc/ntty.rs

@@ -785,14 +785,12 @@ impl NTtyData {
         signal: Signal,
     ) {
         // 先处理信号
-        let mut ctrl_info = tty.core().contorl_info_irqsave();
+        let ctrl_info = tty.core().contorl_info_irqsave();
         let pg = ctrl_info.pgid;
         if let Some(pg) = pg {
             let _ = Syscall::kill(pg, signal as i32);
         }
 
-        ctrl_info.pgid = None;
-
         if !termios.local_mode.contains(LocalMode::NOFLSH) {
             // 重置
             self.echo_head = 0;

kernel/src/process/fork.rs

@@ -169,11 +169,6 @@ impl ProcessManager {
 
         let pcb = ProcessControlBlock::new(name, new_kstack);
 
-        // TODO: 注意！这里设置tty的操作不符合Linux的行为！（毕竟创建进程不一定要fork，也可以用clone来创建）
-        // 正确做法应该是在实现进程组之后去管理前台进程组。
-        pcb.sig_info_mut()
-            .set_tty(current_pcb.sig_info_irqsave().tty());
-
         let mut args = KernelCloneArgs::new();
         args.flags = clone_flags;
         args.exit_signal = Signal::SIGCHLD;

kernel/src/process/mod.rs

@@ -705,16 +705,17 @@ impl ProcessControlBlock {
 
     #[inline(never)]
     fn do_create_pcb(name: String, kstack: KernelStack, is_idle: bool) -> Arc<Self> {
-        let (pid, ppid, cwd, cred) = if is_idle {
+        let (pid, ppid, cwd, cred, tty) = if is_idle {
             let cred = INIT_CRED.clone();
-            (Pid(0), Pid(0), "/".to_string(), cred)
+            (Pid(0), Pid(0), "/".to_string(), cred, None)
         } else {
             let ppid = ProcessManager::current_pcb().pid();
             let mut cred = ProcessManager::current_pcb().cred();
             cred.cap_permitted = cred.cap_ambient;
             cred.cap_effective = cred.cap_ambient;
             let cwd = ProcessManager::current_pcb().basic().cwd();
-            (Self::generate_pid(), ppid, cwd, cred)
+            let tty = ProcessManager::current_pcb().sig_info_irqsave().tty();
+            (Self::generate_pid(), ppid, cwd, cred, tty)
         };
 
         let basic_info = ProcessBasicInfo::new(Pid(0), ppid, Pid(0), name, cwd, None);
@@ -754,6 +755,8 @@ impl ProcessControlBlock {
             cred: SpinLock::new(cred),
         };
 
+        pcb.sig_info.write().set_tty(tty);
+
         // 初始化系统调用栈
         #[cfg(target_arch = "x86_64")]
         pcb.arch_info