138 lines
2.6 KiB
C
138 lines
2.6 KiB
C
/*
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* Controller of read/write threads for virtio-trace
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*
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* Copyright (C) 2012 Hitachi, Ltd.
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* Created by Yoshihiro Yunomae <yoshihiro.yunomae.ez@hitachi.com>
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* Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
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*
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* Licensed under GPL version 2 only.
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*
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*/
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#define _GNU_SOURCE
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#include <fcntl.h>
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#include <poll.h>
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#include <signal.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "trace-agent.h"
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#define HOST_MSG_SIZE 256
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#define EVENT_WAIT_MSEC 100
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static volatile sig_atomic_t global_signal_val;
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bool global_sig_receive; /* default false */
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bool global_run_operation; /* default false*/
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/* Handle SIGTERM/SIGINT/SIGQUIT to exit */
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static void signal_handler(int sig)
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{
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global_signal_val = sig;
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}
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int rw_ctl_init(const char *ctl_path)
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{
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int ctl_fd;
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ctl_fd = open(ctl_path, O_RDONLY);
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if (ctl_fd == -1) {
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pr_err("Cannot open ctl_fd\n");
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goto error;
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}
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return ctl_fd;
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error:
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exit(EXIT_FAILURE);
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}
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static int wait_order(int ctl_fd)
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{
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struct pollfd poll_fd;
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int ret = 0;
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while (!global_sig_receive) {
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poll_fd.fd = ctl_fd;
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poll_fd.events = POLLIN;
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ret = poll(&poll_fd, 1, EVENT_WAIT_MSEC);
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if (global_signal_val) {
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global_sig_receive = true;
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pr_info("Receive interrupt %d\n", global_signal_val);
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/* Wakes rw-threads when they are sleeping */
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if (!global_run_operation)
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pthread_cond_broadcast(&cond_wakeup);
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ret = -1;
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break;
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}
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if (ret < 0) {
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pr_err("Polling error\n");
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goto error;
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}
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if (ret)
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break;
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};
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return ret;
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error:
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exit(EXIT_FAILURE);
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}
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/*
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* contol read/write threads by handling global_run_operation
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*/
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void *rw_ctl_loop(int ctl_fd)
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{
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ssize_t rlen;
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char buf[HOST_MSG_SIZE];
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int ret;
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/* Setup signal handlers */
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signal(SIGTERM, signal_handler);
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signal(SIGINT, signal_handler);
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signal(SIGQUIT, signal_handler);
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while (!global_sig_receive) {
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ret = wait_order(ctl_fd);
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if (ret < 0)
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break;
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rlen = read(ctl_fd, buf, sizeof(buf));
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if (rlen < 0) {
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pr_err("read data error in ctl thread\n");
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goto error;
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}
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if (rlen == 2 && buf[0] == '1') {
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/*
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* If host writes '1' to a control path,
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* this controller wakes all read/write threads.
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*/
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global_run_operation = true;
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pthread_cond_broadcast(&cond_wakeup);
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pr_debug("Wake up all read/write threads\n");
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} else if (rlen == 2 && buf[0] == '0') {
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/*
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* If host writes '0' to a control path, read/write
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* threads will wait for notification from Host.
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*/
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global_run_operation = false;
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pr_debug("Stop all read/write threads\n");
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} else
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pr_info("Invalid host notification: %s\n", buf);
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}
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return NULL;
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error:
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exit(EXIT_FAILURE);
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}
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