Signals

Description

API for sending signals and handling incoming signals.

Threads can send signals asynchronously to each other. Kernel provides mechanism to register signal handler, which gets executed whenever thread receives a signal. There are two kinds of signals:

• catchable - kernel supports sending of 32 distinct catchable signals. Kernel doesn't interpret any of them in any way. If such signal is sent to the thread then thread is simply notified of its arrival.
• non-catchable - these signals are mostly system-defined and thread is not able to catch nor react to them. These include stopping and resuming thread, killing it and signalling memory protection violation error.

If thread doesn't register any signal handler, then signal arrival is effectively a no-op for given thread. In any case, arrival of signal will wake thread up, if it is stopped.

__SYSCALL int	signal (int signo, void(*sighandler)(uint32_t))
	Register function as current thread signal handler.
__SYSCALL int	kill (int thread, uint32_t signal)
	Send thread a signal.
#define	SIGALRM   0
#define	SIGKILL   32
#define	SIGSTOP   33
#define	SIGCONT   34
#define	SIGSEGV   35

Macro Definition Documentation

SIGALRM

#define SIGALRM   0

SIGCONT

#define SIGCONT   34

SIGKILL

#define SIGKILL   32

SIGSEGV

#define SIGSEGV   35

SIGSTOP

#define SIGSTOP   33

Function Documentation

kill()

__SYSCALL int kill	(	int	thread,
		uint32_t	signal
	)

Send thread a signal.

Send a signal to the thread.

Parameters

thread	recipient thread id
signal	signal number

Returns

0. Mostly.

signal()

__SYSCALL int signal	(	int	signo,
		void(*)(uint32_t)	sighandler
	)

Register function as current thread signal handler.

Parameters

signo	number of signal
sighandler	address of function which handles the signal

Returns

0. Mostly.