Yoshihiro YUNOMAE | 108fc82 | 2012-08-09 21:31:30 +0900 | [diff] [blame] | 1 | /* |
| 2 | * Controller of read/write threads for virtio-trace |
| 3 | * |
| 4 | * Copyright (C) 2012 Hitachi, Ltd. |
| 5 | * Created by Yoshihiro Yunomae <yoshihiro.yunomae.ez@hitachi.com> |
| 6 | * Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> |
| 7 | * |
| 8 | * Licensed under GPL version 2 only. |
| 9 | * |
| 10 | */ |
| 11 | |
| 12 | #define _GNU_SOURCE |
| 13 | #include <fcntl.h> |
| 14 | #include <poll.h> |
| 15 | #include <signal.h> |
| 16 | #include <stdio.h> |
| 17 | #include <stdlib.h> |
| 18 | #include <unistd.h> |
| 19 | #include "trace-agent.h" |
| 20 | |
| 21 | #define HOST_MSG_SIZE 256 |
| 22 | #define EVENT_WAIT_MSEC 100 |
| 23 | |
| 24 | static volatile sig_atomic_t global_signal_val; |
| 25 | bool global_sig_receive; /* default false */ |
| 26 | bool global_run_operation; /* default false*/ |
| 27 | |
| 28 | /* Handle SIGTERM/SIGINT/SIGQUIT to exit */ |
| 29 | static void signal_handler(int sig) |
| 30 | { |
| 31 | global_signal_val = sig; |
| 32 | } |
| 33 | |
| 34 | int rw_ctl_init(const char *ctl_path) |
| 35 | { |
| 36 | int ctl_fd; |
| 37 | |
| 38 | ctl_fd = open(ctl_path, O_RDONLY); |
| 39 | if (ctl_fd == -1) { |
| 40 | pr_err("Cannot open ctl_fd\n"); |
| 41 | goto error; |
| 42 | } |
| 43 | |
| 44 | return ctl_fd; |
| 45 | |
| 46 | error: |
| 47 | exit(EXIT_FAILURE); |
| 48 | } |
| 49 | |
| 50 | static int wait_order(int ctl_fd) |
| 51 | { |
| 52 | struct pollfd poll_fd; |
| 53 | int ret = 0; |
| 54 | |
| 55 | while (!global_sig_receive) { |
| 56 | poll_fd.fd = ctl_fd; |
| 57 | poll_fd.events = POLLIN; |
| 58 | |
| 59 | ret = poll(&poll_fd, 1, EVENT_WAIT_MSEC); |
| 60 | |
| 61 | if (global_signal_val) { |
| 62 | global_sig_receive = true; |
| 63 | pr_info("Receive interrupt %d\n", global_signal_val); |
| 64 | |
| 65 | /* Wakes rw-threads when they are sleeping */ |
| 66 | if (!global_run_operation) |
| 67 | pthread_cond_broadcast(&cond_wakeup); |
| 68 | |
| 69 | ret = -1; |
| 70 | break; |
| 71 | } |
| 72 | |
| 73 | if (ret < 0) { |
| 74 | pr_err("Polling error\n"); |
| 75 | goto error; |
| 76 | } |
| 77 | |
| 78 | if (ret) |
| 79 | break; |
| 80 | }; |
| 81 | |
| 82 | return ret; |
| 83 | |
| 84 | error: |
| 85 | exit(EXIT_FAILURE); |
| 86 | } |
| 87 | |
| 88 | /* |
| 89 | * contol read/write threads by handling global_run_operation |
| 90 | */ |
| 91 | void *rw_ctl_loop(int ctl_fd) |
| 92 | { |
| 93 | ssize_t rlen; |
| 94 | char buf[HOST_MSG_SIZE]; |
| 95 | int ret; |
| 96 | |
| 97 | /* Setup signal handlers */ |
| 98 | signal(SIGTERM, signal_handler); |
| 99 | signal(SIGINT, signal_handler); |
| 100 | signal(SIGQUIT, signal_handler); |
| 101 | |
| 102 | while (!global_sig_receive) { |
| 103 | |
| 104 | ret = wait_order(ctl_fd); |
| 105 | if (ret < 0) |
| 106 | break; |
| 107 | |
| 108 | rlen = read(ctl_fd, buf, sizeof(buf)); |
| 109 | if (rlen < 0) { |
| 110 | pr_err("read data error in ctl thread\n"); |
| 111 | goto error; |
| 112 | } |
| 113 | |
| 114 | if (rlen == 2 && buf[0] == '1') { |
| 115 | /* |
| 116 | * If host writes '1' to a control path, |
| 117 | * this controller wakes all read/write threads. |
| 118 | */ |
| 119 | global_run_operation = true; |
| 120 | pthread_cond_broadcast(&cond_wakeup); |
| 121 | pr_debug("Wake up all read/write threads\n"); |
| 122 | } else if (rlen == 2 && buf[0] == '0') { |
| 123 | /* |
| 124 | * If host writes '0' to a control path, read/write |
| 125 | * threads will wait for notification from Host. |
| 126 | */ |
| 127 | global_run_operation = false; |
| 128 | pr_debug("Stop all read/write threads\n"); |
| 129 | } else |
| 130 | pr_info("Invalid host notification: %s\n", buf); |
| 131 | } |
| 132 | |
| 133 | return NULL; |
| 134 | |
| 135 | error: |
| 136 | exit(EXIT_FAILURE); |
| 137 | } |