/*
 * Controller of read/write threads for virtio-trace
 *
 * Copyright (C) 2012 Hitachi, Ltd.
 * Created by Yoshihiro Yunomae <yoshihiro.yunomae.ez@hitachi.com>
 *            Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
 *
 * Licensed under GPL version 2 only.
 *
 */

#define _GNU_SOURCE
#include <fcntl.h>
#include <poll.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include "trace-agent.h"

#define HOST_MSG_SIZE		256
#define EVENT_WAIT_MSEC		100

static volatile sig_atomic_t global_signal_val;
bool global_sig_receive;	/* default false */
bool global_run_operation;	/* default false*/

/* Handle SIGTERM/SIGINT/SIGQUIT to exit */
static void signal_handler(int sig)
{
	global_signal_val = sig;
}

int rw_ctl_init(const char *ctl_path)
{
	int ctl_fd;

	ctl_fd = open(ctl_path, O_RDONLY);
	if (ctl_fd == -1) {
		pr_err("Cannot open ctl_fd\n");
		goto error;
	}

	return ctl_fd;

error:
	exit(EXIT_FAILURE);
}

static int wait_order(int ctl_fd)
{
	struct pollfd poll_fd;
	int ret = 0;

	while (!global_sig_receive) {
		poll_fd.fd = ctl_fd;
		poll_fd.events = POLLIN;

		ret = poll(&poll_fd, 1, EVENT_WAIT_MSEC);

		if (global_signal_val) {
			global_sig_receive = true;
			pr_info("Receive interrupt %d\n", global_signal_val);

			/* Wakes rw-threads when they are sleeping */
			if (!global_run_operation)
				pthread_cond_broadcast(&cond_wakeup);

			ret = -1;
			break;
		}

		if (ret < 0) {
			pr_err("Polling error\n");
			goto error;
		}

		if (ret)
			break;
	};

	return ret;

error:
	exit(EXIT_FAILURE);
}

/*
 * contol read/write threads by handling global_run_operation
 */
void *rw_ctl_loop(int ctl_fd)
{
	ssize_t rlen;
	char buf[HOST_MSG_SIZE];
	int ret;

	/* Setup signal handlers */
	signal(SIGTERM, signal_handler);
	signal(SIGINT, signal_handler);
	signal(SIGQUIT, signal_handler);

	while (!global_sig_receive) {

		ret = wait_order(ctl_fd);
		if (ret < 0)
			break;

		rlen = read(ctl_fd, buf, sizeof(buf));
		if (rlen < 0) {
			pr_err("read data error in ctl thread\n");
			goto error;
		}

		if (rlen == 2 && buf[0] == '1') {
			/*
			 * If host writes '1' to a control path,
			 * this controller wakes all read/write threads.
			 */
			global_run_operation = true;
			pthread_cond_broadcast(&cond_wakeup);
			pr_debug("Wake up all read/write threads\n");
		} else if (rlen == 2 && buf[0] == '0') {
			/*
			 * If host writes '0' to a control path, read/write
			 * threads will wait for notification from Host.
			 */
			global_run_operation = false;
			pr_debug("Stop all read/write threads\n");
		} else
			pr_info("Invalid host notification: %s\n", buf);
	}

	return NULL;

error:
	exit(EXIT_FAILURE);
}
root</a>/<a href='/cgit.cgi/linux/net-next.git/diff/include?id=7a7b5df84b6b4e5d599c7289526eed96541a0654'>include</a>/<a href='/cgit.cgi/linux/net-next.git/diff/include/net?id=7a7b5df84b6b4e5d599c7289526eed96541a0654'>net</a>/<a href='/cgit.cgi/linux/net-next.git/diff/include/net/gen_stats.h?id=7a7b5df84b6b4e5d599c7289526eed96541a0654'>gen_stats.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='7a7b5df84b6b4e5d599c7289526eed96541a0654'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=7a7b5df84b6b4e5d599c7289526eed96541a0654'>Diffstat</a> (limited to 'include/net/gen_stats.h')</div><table summary='diffstat' class='diffstat'>