event.c

dgstation relook 400 sample code to run shared plugin process in background.

#include <linux/input.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/poll.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <errno.h>
#include <stdio.h>

static int event_fd;

int plugin_event_init( char *dev )
{
	event_fd = open( dev, O_RDONLY|O_NONBLOCK );
	if( event_fd < 0 )
	{
		perror( "event open" );
		return -1;
	}

	return 0;
}

void plugin_event_cleanup( void )
{
	close( event_fd );
}

int plugin_event_read_nowait( int *code, int *value )
{
	int ret;
	struct input_event event;

	ret = read( event_fd, &event, sizeof(event) );
	if( ret != sizeof(event) )
		return -1;

	if( event.type != EV_KEY )
		return -1;

	*code = event.code;
	*value = event.value;

	return 0;
}

int plugin_event_read( int *code, int *value )
{
	int ret;
	struct pollfd ufds;

	ufds.fd = event_fd;
	ufds.events = POLLIN;
	ufds.revents = 0;

	ret = poll( &ufds, 1, 0 );
	if( ret > 0 )
	{
		/* got event */
		return plugin_event_read_nowait( code, value );
	}

	/* timeout */
	return -1;
}