diff options
Diffstat (limited to 'library/std/src/sys')
| -rw-r--r-- | library/std/src/sys/pal/unix/thread.rs | 30 |
1 files changed, 24 insertions, 6 deletions
diff --git a/library/std/src/sys/pal/unix/thread.rs b/library/std/src/sys/pal/unix/thread.rs index 0fa610eebb4..c9dcc5ad97a 100644 --- a/library/std/src/sys/pal/unix/thread.rs +++ b/library/std/src/sys/pal/unix/thread.rs @@ -267,14 +267,32 @@ impl Thread { #[cfg(target_os = "espidf")] pub fn sleep(dur: Duration) { - let mut micros = dur.as_micros(); - unsafe { - while micros > 0 { - let st = if micros > u32::MAX as u128 { u32::MAX } else { micros as u32 }; + // ESP-IDF does not have `nanosleep`, so we use `usleep` instead. + // As per the documentation of `usleep`, it is expected to support + // sleep times as big as at least up to 1 second. + // + // ESP-IDF does support almost up to `u32::MAX`, but due to a potential integer overflow in its + // `usleep` implementation + // (https://github.com/espressif/esp-idf/blob/d7ca8b94c852052e3bc33292287ef4dd62c9eeb1/components/newlib/time.c#L210), + // we limit the sleep time to the maximum one that would not cause the underlying `usleep` implementation to overflow + // (`portTICK_PERIOD_MS` can be anything between 1 to 1000, and is 10 by default). + const MAX_MICROS: u32 = u32::MAX - 1_000_000 - 1; + + // Add any nanoseconds smaller than a microsecond as an extra microsecond + // so as to comply with the `std::thread::sleep` contract which mandates + // implementations to sleep for _at least_ the provided `dur`. + // We can't overflow `micros` as it is a `u128`, while `Duration` is a pair of + // (`u64` secs, `u32` nanos), where the nanos are strictly smaller than 1 second + // (i.e. < 1_000_000_000) + let mut micros = dur.as_micros() + if dur.subsec_nanos() % 1_000 > 0 { 1 } else { 0 }; + + while micros > 0 { + let st = if micros > MAX_MICROS as u128 { MAX_MICROS } else { micros as u32 }; + unsafe { libc::usleep(st); - - micros -= st as u128; } + + micros -= st as u128; } } |