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135 lines
2.6 KiB
135 lines
2.6 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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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 <[email protected]> |
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* Masami Hiramatsu <[email protected]> |
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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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