问题
How to get signal from kernel space to user space?
回答1:
To get the signal from kernel to user space use the following code in your user space and kernel space code as below :
user space application :
signal(SIGIO, &signal_handler_func);
fcntl(fd, F_SETOWN, getpid());
oflags = fcntl(fd, F_GETFL);
fcntl(fd, F_SETFL, oflags | FASYNC);
define signal_handler_func function :
void signal_handler_func (int sig)
{
//handle the action corresponding to the signal here
}
kernel Space Module :
int ret = 0;
struct siginfo info;
memset(&info, 0, sizeof(struct siginfo));
info.si_signo = SIG_TEST;
info.si_code = SI_QUEUE;
info.si_int = 1234;
send_sig_info(SIG_TEST, &info, t);//send signal to user land
t is the PID of the user application.
回答2:
Use the kernel API function kill_proc_info(int sig, struct siginfo *info, pid_t pid)
NOTE This is actually a bad answer. The functions does send a signal to user space but the right way to do this, as the asker intended is to use the fasync character device method as documented here: http://www.xml.com/ldd/chapter/book/ch05.html#t4
回答3:
There is something called a NetLink interface which provides a set of API's for communication between a kernel process and a user process.It is similar to the socket interface and the communication is asynchronous and hence is preferred to IOCTL.
Overview here: http://www.linuxjournal.com/article/7356
来源：https://stackoverflow.com/questions/5634466/sending-signal-from-kernel-to-user-space