tracehook: get_signal_to_deliver (7bcf6a2c) · Commits · 戴 / test

include/linux/tracehook.h

+29 −0

Original line number	Diff line number	Diff line
		@@ -422,4 +422,33 @@ static inline int tracehook_consider_fatal_signal(struct task_struct *task,
		return (task_ptrace(task) & PT_PTRACED) != 0;
		}

		/**
		* tracehook_get_signal - deliver synthetic signal to traced task
		* @task: @current
		* @regs: task_pt_regs(@current)
		* @info: details of synthetic signal
		* @return_ka: sigaction for synthetic signal
		*
		* Return zero to check for a real pending signal normally.
		* Return -1 after releasing the siglock to repeat the check.
		* Return a signal number to induce an artifical signal delivery,
		* setting @info and @return_ka to specify its details and behavior.
		*
		* The @return_ka->sa_handler value controls the disposition of the
		* signal, no matter the signal number. For %SIG_DFL, the return value
		* is a representative signal to indicate the behavior (e.g. %SIGTERM
		* for death, %SIGQUIT for core dump, %SIGSTOP for job control stop,
		* %SIGTSTP for stop unless in an orphaned pgrp), but the signal number
		* reported will be @info->si_signo instead.
		*
		* Called with @task->sighand->siglock held, before dequeuing pending signals.
		*/
		static inline int tracehook_get_signal(struct task_struct *task,
		struct pt_regs *regs,
		siginfo_t *info,
		struct k_sigaction *return_ka)
		{
		return 0;
		}

		#endif /* <linux/tracehook.h> */

kernel/signal.c

+27 −11

Original line number	Diff line number	Diff line
		@@ -1754,17 +1754,33 @@ relock:
		do_signal_stop(0))
		goto relock;

		signr = dequeue_signal(current, &current->blocked, info);
		/*
		* Tracing can induce an artifical signal and choose sigaction.
		* The return value in @signr determines the default action,
		* but @info->si_signo is the signal number we will report.
		*/
		signr = tracehook_get_signal(current, regs, info, return_ka);
		if (unlikely(signr < 0))
		goto relock;
		if (unlikely(signr != 0))
		ka = return_ka;
		else {
		signr = dequeue_signal(current, &current->blocked,
		info);

		if (!signr)
		break; /* will return 0 */

		if (signr != SIGKILL) {
		signr = ptrace_signal(signr, info, regs, cookie);
		signr = ptrace_signal(signr, info,
		regs, cookie);
		if (!signr)
		continue;
		}

		ka = &sighand->action[signr-1];
		}

		if (ka->sa.sa_handler == SIG_IGN) /* Do nothing. */
		continue;
		if (ka->sa.sa_handler != SIG_DFL) {
		@@ -1812,7 +1828,7 @@ relock:
		spin_lock_irq(&sighand->siglock);
		}

		if (likely(do_signal_stop(signr))) {
		if (likely(do_signal_stop(info->si_signo))) {
		/* It released the siglock. */
		goto relock;
		}
		@@ -1833,7 +1849,7 @@ relock:

		if (sig_kernel_coredump(signr)) {
		if (print_fatal_signals)
		print_fatal_signal(regs, signr);
		print_fatal_signal(regs, info->si_signo);
		/*
		* If it was able to dump core, this kills all
		* other threads in the group and synchronizes with
		@@ -1842,13 +1858,13 @@ relock:
		* first and our do_group_exit call below will use
		* that value and ignore the one we pass it.
		*/
		do_coredump((long)signr, signr, regs);
		do_coredump(info->si_signo, info->si_signo, regs);
		}

		/*
		* Death signals, no core dump.
		*/
		do_group_exit(signr);
		do_group_exit(info->si_signo);
		/* NOTREACHED */
		}
		spin_unlock_irq(&sighand->siglock);

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