void do_signal()

in kernel/signal.c [95:141]

• 28 lines of code
• 10 McCabe index (conditional complexity)

void do_signal(struct pt_regs *regs)
{
	struct ksignal ksig;
	int handled_sig = 0;

	while (get_signal(&ksig)) {
		handled_sig = 1;
		/* Whee!  Actually deliver the signal.  */
		handle_signal(&ksig, regs);
	}

	/* Did we come from a system call? */
	if (!handled_sig && (PT_REGS_SYSCALL_NR(regs) >= 0)) {
		/* Restart the system call - no handlers present */
		switch (PT_REGS_SYSCALL_RET(regs)) {
		case -ERESTARTNOHAND:
		case -ERESTARTSYS:
		case -ERESTARTNOINTR:
			PT_REGS_ORIG_SYSCALL(regs) = PT_REGS_SYSCALL_NR(regs);
			PT_REGS_RESTART_SYSCALL(regs);
			break;
		case -ERESTART_RESTARTBLOCK:
			PT_REGS_ORIG_SYSCALL(regs) = __NR_restart_syscall;
			PT_REGS_RESTART_SYSCALL(regs);
			break;
		}
	}

	/*
	 * This closes a way to execute a system call on the host.  If
	 * you set a breakpoint on a system call instruction and singlestep
	 * from it, the tracing thread used to PTRACE_SINGLESTEP the process
	 * rather than PTRACE_SYSCALL it, allowing the system call to execute
	 * on the host.  The tracing thread will check this flag and
	 * PTRACE_SYSCALL if necessary.
	 */
	if (current->ptrace & PT_DTRACE)
		current->thread.singlestep_syscall =
			is_syscall(PT_REGS_IP(&current->thread.regs));

	/*
	 * if there's no signal to deliver, we just put the saved sigmask
	 * back
	 */
	if (!handled_sig)
		restore_saved_sigmask();
}