src/shims/time.rs

   1 use std::time::{Duration, Instant, SystemTime};
   2
   3 use crate::*;
   4 use thread::Time;
   5
   6 /// Returns the time elapsed between the provided time and the unix epoch as a `Duration`.
   7 pub fn system_time_to_duration<'tcx>(time: &SystemTime) -> InterpResult<'tcx, Duration> {
   8     time.duration_since(SystemTime::UNIX_EPOCH)
   9         .map_err(|_| err_unsup_format!("times before the Unix epoch are not supported").into())
  10 }
  11
  12 impl<'mir, 'tcx: 'mir> EvalContextExt<'mir, 'tcx> for crate::MiriEvalContext<'mir, 'tcx> {}
  13 pub trait EvalContextExt<'mir, 'tcx: 'mir>: crate::MiriEvalContextExt<'mir, 'tcx> {
  14     fn clock_gettime(
  15         &mut self,
  16         clk_id_op: &OpTy<'tcx, Tag>,
  17         tp_op: &OpTy<'tcx, Tag>,
  18     ) -> InterpResult<'tcx, i32> {
  19         // This clock support is deliberately minimal because a lot of clock types have fiddly
  20         // properties (is it possible for Miri to be suspended independently of the host?). If you
  21         // have a use for another clock type, please open an issue.
  22
  23         let this = self.eval_context_mut();
  24
  25         this.assert_target_os("linux", "clock_gettime");
  26         this.check_no_isolation("`clock_gettime`")?;
  27
  28         let clk_id = this.read_scalar(clk_id_op)?.to_i32()?;
  29
  30         // Linux has two main kinds of clocks. REALTIME clocks return the actual time since the
  31         // Unix epoch, including effects which may cause time to move backwards such as NTP.
  32         // Linux further distinguishes regular and "coarse" clocks, but the "coarse" version
  33         // is just specified to be "faster and less precise", so we implement both the same way.
  34         let absolute_clocks =
  35             [this.eval_libc_i32("CLOCK_REALTIME")?, this.eval_libc_i32("CLOCK_REALTIME_COARSE")?];
  36         // The second kind is MONOTONIC clocks for which 0 is an arbitrary time point, but they are
  37         // never allowed to go backwards. We don't need to do any additonal monotonicity
  38         // enforcement because std::time::Instant already guarantees that it is monotonic.
  39         let relative_clocks =
  40             [this.eval_libc_i32("CLOCK_MONOTONIC")?, this.eval_libc_i32("CLOCK_MONOTONIC_COARSE")?];
  41
  42         let duration = if absolute_clocks.contains(&clk_id) {
  43             system_time_to_duration(&SystemTime::now())?
  44         } else if relative_clocks.contains(&clk_id) {
  45             Instant::now().duration_since(this.machine.time_anchor)
  46         } else {
  47             let einval = this.eval_libc("EINVAL")?;
  48             this.set_last_error(einval)?;
  49             return Ok(-1);
  50         };
  51
  52         let tv_sec = duration.as_secs();
  53         let tv_nsec = duration.subsec_nanos();
  54
  55         this.write_int_fields(&[tv_sec.into(), tv_nsec.into()], &this.deref_operand(tp_op)?)?;
  56
  57         Ok(0)
  58     }
  59
  60     fn gettimeofday(
  61         &mut self,
  62         tv_op: &OpTy<'tcx, Tag>,
  63         tz_op: &OpTy<'tcx, Tag>,
  64     ) -> InterpResult<'tcx, i32> {
  65         let this = self.eval_context_mut();
  66
  67         this.assert_target_os("macos", "gettimeofday");
  68         this.check_no_isolation("`gettimeofday`")?;
  69
  70         // Using tz is obsolete and should always be null
  71         let tz = this.read_pointer(tz_op)?;
  72         if !this.ptr_is_null(tz)? {
  73             let einval = this.eval_libc("EINVAL")?;
  74             this.set_last_error(einval)?;
  75             return Ok(-1);
  76         }
  77
  78         let duration = system_time_to_duration(&SystemTime::now())?;
  79         let tv_sec = duration.as_secs();
  80         let tv_usec = duration.subsec_micros();
  81
  82         this.write_int_fields(&[tv_sec.into(), tv_usec.into()], &this.deref_operand(tv_op)?)?;
  83
  84         Ok(0)
  85     }
  86
  87     #[allow(non_snake_case)]
  88     fn GetSystemTimeAsFileTime(&mut self, LPFILETIME_op: &OpTy<'tcx, Tag>) -> InterpResult<'tcx> {
  89         let this = self.eval_context_mut();
  90
  91         this.assert_target_os("windows", "GetSystemTimeAsFileTime");
  92         this.check_no_isolation("`GetSystemTimeAsFileTime`")?;
  93
  94         let NANOS_PER_SEC = this.eval_windows_u64("time", "NANOS_PER_SEC")?;
  95         let INTERVALS_PER_SEC = this.eval_windows_u64("time", "INTERVALS_PER_SEC")?;
  96         let INTERVALS_TO_UNIX_EPOCH = this.eval_windows_u64("time", "INTERVALS_TO_UNIX_EPOCH")?;
  97         let NANOS_PER_INTERVAL = NANOS_PER_SEC / INTERVALS_PER_SEC;
  98         let SECONDS_TO_UNIX_EPOCH = INTERVALS_TO_UNIX_EPOCH / INTERVALS_PER_SEC;
  99
 100         let duration = system_time_to_duration(&SystemTime::now())?
 101             + Duration::from_secs(SECONDS_TO_UNIX_EPOCH);
 102         let duration_ticks = u64::try_from(duration.as_nanos() / u128::from(NANOS_PER_INTERVAL))
 103             .map_err(|_| err_unsup_format!("programs running more than 2^64 Windows ticks after the Windows epoch are not supported"))?;
 104
 105         let dwLowDateTime = u32::try_from(duration_ticks & 0x00000000FFFFFFFF).unwrap();
 106         let dwHighDateTime = u32::try_from((duration_ticks & 0xFFFFFFFF00000000) >> 32).unwrap();
 107         this.write_int_fields(
 108             &[dwLowDateTime.into(), dwHighDateTime.into()],
 109             &this.deref_operand(LPFILETIME_op)?,
 110         )?;
 111
 112         Ok(())
 113     }
 114
 115     #[allow(non_snake_case)]
 116     fn QueryPerformanceCounter(
 117         &mut self,
 118         lpPerformanceCount_op: &OpTy<'tcx, Tag>,
 119     ) -> InterpResult<'tcx, i32> {
 120         let this = self.eval_context_mut();
 121
 122         this.assert_target_os("windows", "QueryPerformanceCounter");
 123         this.check_no_isolation("`QueryPerformanceCounter`")?;
 124
 125         // QueryPerformanceCounter uses a hardware counter as its basis.
 126         // Miri will emulate a counter with a resolution of 1 nanosecond.
 127         let duration = Instant::now().duration_since(this.machine.time_anchor);
 128         let qpc = i64::try_from(duration.as_nanos()).map_err(|_| {
 129             err_unsup_format!("programs running longer than 2^63 nanoseconds are not supported")
 130         })?;
 131         this.write_scalar(
 132             Scalar::from_i64(qpc),
 133             &this.deref_operand(lpPerformanceCount_op)?.into(),
 134         )?;
 135         Ok(-1) // return non-zero on success
 136     }
 137
 138     #[allow(non_snake_case)]
 139     fn QueryPerformanceFrequency(
 140         &mut self,
 141         lpFrequency_op: &OpTy<'tcx, Tag>,
 142     ) -> InterpResult<'tcx, i32> {
 143         let this = self.eval_context_mut();
 144
 145         this.assert_target_os("windows", "QueryPerformanceFrequency");
 146         this.check_no_isolation("`QueryPerformanceFrequency`")?;
 147
 148         // Retrieves the frequency of the hardware performance counter.
 149         // The frequency of the performance counter is fixed at system boot and
 150         // is consistent across all processors.
 151         // Miri emulates a "hardware" performance counter with a resolution of 1ns,
 152         // and thus 10^9 counts per second.
 153         this.write_scalar(
 154             Scalar::from_i64(1_000_000_000),
 155             &this.deref_operand(lpFrequency_op)?.into(),
 156         )?;
 157         Ok(-1) // Return non-zero on success
 158     }
 159
 160     fn mach_absolute_time(&self) -> InterpResult<'tcx, u64> {
 161         let this = self.eval_context_ref();
 162
 163         this.assert_target_os("macos", "mach_absolute_time");
 164         this.check_no_isolation("`mach_absolute_time`")?;
 165
 166         // This returns a u64, with time units determined dynamically by `mach_timebase_info`.
 167         // We return plain nanoseconds.
 168         let duration = Instant::now().duration_since(this.machine.time_anchor);
 169         u64::try_from(duration.as_nanos()).map_err(|_| {
 170             err_unsup_format!("programs running longer than 2^64 nanoseconds are not supported")
 171                 .into()
 172         })
 173     }
 174
 175     fn mach_timebase_info(&mut self, info_op: &OpTy<'tcx, Tag>) -> InterpResult<'tcx, i32> {
 176         let this = self.eval_context_mut();
 177
 178         this.assert_target_os("macos", "mach_timebase_info");
 179         this.check_no_isolation("`mach_timebase_info`")?;
 180
 181         let info = this.deref_operand(info_op)?;
 182
 183         // Since our emulated ticks in `mach_absolute_time` *are* nanoseconds,
 184         // no scaling needs to happen.
 185         let (numer, denom) = (1, 1);
 186         this.write_int_fields(&[numer.into(), denom.into()], &info)?;
 187
 188         Ok(0) // KERN_SUCCESS
 189     }
 190
 191     fn nanosleep(
 192         &mut self,
 193         req_op: &OpTy<'tcx, Tag>,
 194         _rem: &OpTy<'tcx, Tag>,
 195     ) -> InterpResult<'tcx, i32> {
 196         // Signal handlers are not supported, so rem will never be written to.
 197
 198         let this = self.eval_context_mut();
 199
 200         this.check_no_isolation("`nanosleep`")?;
 201
 202         let duration = match this.read_timespec(&this.deref_operand(req_op)?)? {
 203             Some(duration) => duration,
 204             None => {
 205                 let einval = this.eval_libc("EINVAL")?;
 206                 this.set_last_error(einval)?;
 207                 return Ok(-1);
 208             }
 209         };
 210         let timeout_time = Time::Monotonic(Instant::now().checked_add(duration).unwrap());
 211
 212         let active_thread = this.get_active_thread();
 213         this.block_thread(active_thread);
 214
 215         this.register_timeout_callback(
 216             active_thread,
 217             timeout_time,
 218             Box::new(move |ecx| {
 219                 ecx.unblock_thread(active_thread);
 220                 Ok(())
 221             }),
 222         );
 223
 224         Ok(0)
 225     }
 226 }