1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180

//! POSIX based timer

use core::{mem, ptr, time};

use crate::{TimerState, Timer};

use libc::{c_int, c_void, clockid_t, siginfo_t, suseconds_t, time_t, timespec, CLOCK_MONOTONIC};

#[repr(C)]
struct itimerspec {
    it_interval: timespec,
    it_value: timespec,
}

extern "C" {
    fn timer_create(clockid: clockid_t, sevp: *mut libc::sigevent, timerid: *mut usize) -> c_int;
    fn timer_settime(timerid: usize, flags: c_int, new_value: *const itimerspec, old_value: *mut itimerspec) -> c_int;
    fn timer_delete(timerid: usize);
}

const TIMER_SIG: c_int = 40;
const INTERVAL_SIG: c_int = TIMER_SIG + 1;

unsafe fn get_value(info: *mut siginfo_t) -> *const TimerState {
    //TODO: Support BSD, but this shit requires some hacking due to slightly different struct
    //      Most likely needs libc to sort out this shit
    let raw_bytes = (*info)._pad;
    let val: libc::sigval = ptr::read(raw_bytes[3..].as_ptr() as *const _);

    val.sival_ptr as *const TimerState
}

unsafe extern "C" fn timer_handler(_sig: c_int, si: *mut siginfo_t, _uc: *mut c_void) {
    let state = get_value(si);

    (*state).wake();
}

unsafe extern "C" fn interval_handler(_sig: c_int, si: *mut siginfo_t, _uc: *mut c_void) {
    let state = get_value(si);

    (*state).wake_by_ref();
}

fn init() {
    let mut sa_mask: libc::sigset_t = unsafe { mem::uninitialized() };
    unsafe {
        libc::sigemptyset(&mut sa_mask);
    }

    let timer_sig = libc::sigaction {
        sa_flags: libc::SA_SIGINFO,
        sa_sigaction: timer_handler as usize,
        sa_mask,
        #[cfg(any(target_os = "linux", target_os = "android"))]
        sa_restorer: None,
    };

    unsafe {
        assert_ne!(libc::sigaction(TIMER_SIG, &timer_sig, ptr::null_mut()), -1);
    }

    let interval_sig = libc::sigaction {
        sa_flags: libc::SA_SIGINFO,
        sa_sigaction: interval_handler as usize,
        sa_mask,
        #[cfg(any(target_os = "linux", target_os = "android"))]
        sa_restorer: None,
    };

    unsafe {
        assert_ne!(libc::sigaction(INTERVAL_SIG, &interval_sig, ptr::null_mut()), -1);
    }
}

lazy_static::lazy_static! {
    static ref RUNTIME: () = {
        init();
    };
}

///Posix Timer
///
///Currently implemented only for `Linux` and `Android` as BSD systems
///proved to be a bit  problematic
pub struct PosixTimer {
    handle: usize,
    state: *const TimerState,
}

impl PosixTimer {
    fn init_raw_timer(&mut self, sigev_signo: c_int, state: *const TimerState) {
        self.reset();

        let mut event: libc::sigevent = unsafe { mem::zeroed() };

        event.sigev_value = libc::sigval {
            sival_ptr: state as *mut _,
        };
        event.sigev_signo = sigev_signo;
        event.sigev_notify = libc::SIGEV_SIGNAL;
        event.sigev_notify_thread_id = 0;

        unsafe {
            assert_eq!(timer_create(CLOCK_MONOTONIC, &mut event, &mut self.handle), 0);
        }
    }

    fn init_timer(&mut self, timeout: time::Duration, is_interval: bool) {
        let it_value = timespec {
            tv_sec: timeout.as_secs() as time_t,
            tv_nsec: timeout.subsec_nanos() as suseconds_t,
        };

        let (signal, it_interval) = match is_interval {
            false => (TIMER_SIG, unsafe { mem::zeroed() }),
            true => (INTERVAL_SIG, it_value.clone())
        };

        let mut new_value = itimerspec {
            it_interval,
            it_value,
        };

        self.init_raw_timer(signal, self.state);

        unsafe {
            assert_eq!(timer_settime(self.handle, 0, &mut new_value, ptr::null_mut()), 0);
        }
    }
}

impl Timer for PosixTimer {
    fn new(state: *const TimerState) -> Self {
        lazy_static::initialize(&RUNTIME);

        Self {
            handle: 0,
            state,
        }
    }

    #[inline]
    fn reset(&mut self) {
        if self.handle != 0 {
            unsafe {
                //Cancel old timer, if any
                timer_settime(self.handle, 0, &mut mem::zeroed(), ptr::null_mut());
                timer_delete(self.handle);
            }
            self.handle = 0;
        }
    }

    #[inline]
    fn start_delay(&mut self, timeout: time::Duration) {
        self.init_timer(timeout, false);
    }

    #[inline]
    fn start_interval(&mut self, interval: time::Duration) {
        self.init_timer(interval, true);
    }

    fn state(&self) -> &TimerState {
        match unsafe { self.state.as_ref() } {
            Some(state) => state,
            None => unreach!(),
        }
    }
}

impl Drop for PosixTimer {
    fn drop(&mut self) {
        self.reset();
    }
}

unsafe impl Send for PosixTimer {}
unsafe impl Sync for PosixTimer {}