#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

#ifndef O_DIRECT
#define O_DIRECT         040000
#endif

#define array_elements(arr) (sizeof(arr) / sizeof(arr[0]))

struct asys_input {
        int syscall_nr;
	unsigned long cookie;
        unsigned long nr_args;
        unsigned long *args;
};

struct asys_completion {
	long return_code;
	unsigned long cookie;
};

#define SYS_asys_submit 320
#define SYS_asys_await_completion 321

unsigned char buf[512] __attribute__((aligned(512)));

int main(int argc, char **argv)
{
	int fd;
	int i;
	int ret;
	struct timeval tv;

	struct asys_completion comp;
	unsigned long args[] = {0 /* fd */, (unsigned long)buf, 512};
	struct asys_input inp[] = {
		{
			.syscall_nr = SYS_getpid,
			.cookie = 1234,
			.nr_args = 0,
		},
		{
			.syscall_nr = SYS_read,
			.cookie = 5678,
			.nr_args = 3,
			.args = args,
		},
	};

	fd = open("/dev/hda", O_RDONLY|O_DIRECT);
	if (fd < 0) {
		printf("couldn't open /dev/hda\n");
		exit(1);
	}

	args[0] = fd;

	ret = syscall(SYS_asys_submit, &inp, array_elements(inp));
	gettimeofday(&tv, NULL);
	printf("submit returned %d at %ld.%ld\n",
	       ret, tv.tv_sec, tv.tv_usec);

	for (i = 0; i < array_elements(inp) ; i++) {
		ret = syscall(SYS_asys_await_completion, &comp);
		gettimeofday(&tv, NULL);
		printf("completion returned %d at %ld.%ld, "
		       "return code %ld cookie %lu\n", ret, tv.tv_sec,
		       tv.tv_usec, comp.return_code, comp.cookie);
	}

	return 0;
}