diff options
| -rw-r--r-- | src/tools/miri/src/shims/unix/linux_like/eventfd.rs | 55 |
1 files changed, 25 insertions, 30 deletions
diff --git a/src/tools/miri/src/shims/unix/linux_like/eventfd.rs b/src/tools/miri/src/shims/unix/linux_like/eventfd.rs index 4bbe417ea8d..ed81207f54e 100644 --- a/src/tools/miri/src/shims/unix/linux_like/eventfd.rs +++ b/src/tools/miri/src/shims/unix/linux_like/eventfd.rs @@ -62,11 +62,10 @@ impl FileDescription for Event { return ecx.set_last_error_and_return(ErrorKind::InvalidInput, dest); } - // eventfd read at the size of u64. + // Turn the pointer into a place at the right type. let buf_place = ecx.ptr_to_mplace_unaligned(ptr, ty); - let weak_eventfd = self_ref.downgrade(); - eventfd_read(buf_place, dest, weak_eventfd, ecx) + eventfd_read(buf_place, dest, self_ref, ecx) } /// A write call adds the 8-byte integer value supplied in @@ -97,18 +96,10 @@ impl FileDescription for Event { return ecx.set_last_error_and_return(ErrorKind::InvalidInput, dest); } - // Read the user-supplied value from the pointer. + // Turn the pointer into a place at the right type. let buf_place = ecx.ptr_to_mplace_unaligned(ptr, ty); - let num = ecx.read_scalar(&buf_place)?.to_u64()?; - // u64::MAX as input is invalid because the maximum value of counter is u64::MAX - 1. - if num == u64::MAX { - return ecx.set_last_error_and_return(ErrorKind::InvalidInput, dest); - } - // If the addition does not let the counter to exceed the maximum value, update the counter. - // Else, block. - let weak_eventfd = self_ref.downgrade(); - eventfd_write(num, buf_place, dest, weak_eventfd, ecx) + eventfd_write(buf_place, dest, self_ref, ecx) } fn as_unix(&self) -> &dyn UnixFileDescription { @@ -193,20 +184,22 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> { /// Block thread if the value addition will exceed u64::MAX -1, /// else just add the user-supplied value to current counter. fn eventfd_write<'tcx>( - num: u64, buf_place: MPlaceTy<'tcx>, dest: &MPlaceTy<'tcx>, - weak_eventfd: WeakFileDescriptionRef, + eventfd_ref: &FileDescriptionRef, ecx: &mut MiriInterpCx<'tcx>, ) -> InterpResult<'tcx> { - let Some(eventfd_ref) = weak_eventfd.upgrade() else { - throw_unsup_format!("eventfd FD got closed while blocking.") - }; - // Since we pass the weak file description ref, it is guaranteed to be // an eventfd file description. let eventfd = eventfd_ref.downcast::<Event>().unwrap(); + // Figure out which value we should add. + let num = ecx.read_scalar(&buf_place)?.to_u64()?; + // u64::MAX as input is invalid because the maximum value of counter is u64::MAX - 1. + if num == u64::MAX { + return ecx.set_last_error_and_return(ErrorKind::InvalidInput, dest); + } + match eventfd.counter.get().checked_add(num) { Some(new_count @ 0..=MAX_COUNTER) => { // Future `read` calls will synchronize with this write, so update the FD clock. @@ -219,7 +212,7 @@ fn eventfd_write<'tcx>( // The state changed; we check and update the status of all supported event // types for current file description. - ecx.check_and_update_readiness(&eventfd_ref)?; + ecx.check_and_update_readiness(eventfd_ref)?; // Unblock *all* threads previously blocked on `read`. // We need to take out the blocked thread ids and unblock them together, @@ -244,6 +237,7 @@ fn eventfd_write<'tcx>( eventfd.blocked_write_tid.borrow_mut().push(ecx.active_thread()); + let weak_eventfd = eventfd_ref.downgrade(); ecx.block_thread( BlockReason::Eventfd, None, @@ -255,8 +249,10 @@ fn eventfd_write<'tcx>( weak_eventfd: WeakFileDescriptionRef, } @unblock = |this| { - // When we get unblocked, try again. - eventfd_write(num, buf_place, &dest, weak_eventfd, this) + // When we get unblocked, try again. We know the ref is still valid, + // otherwise there couldn't be a `write` that unblocks us. + let eventfd_ref = weak_eventfd.upgrade().unwrap(); + eventfd_write(buf_place, &dest, &eventfd_ref, this) } ), ); @@ -270,13 +266,9 @@ fn eventfd_write<'tcx>( fn eventfd_read<'tcx>( buf_place: MPlaceTy<'tcx>, dest: &MPlaceTy<'tcx>, - weak_eventfd: WeakFileDescriptionRef, + eventfd_ref: &FileDescriptionRef, ecx: &mut MiriInterpCx<'tcx>, ) -> InterpResult<'tcx> { - let Some(eventfd_ref) = weak_eventfd.upgrade() else { - throw_unsup_format!("eventfd FD got closed while blocking.") - }; - // Since we pass the weak file description ref to the callback function, it is guaranteed to be // an eventfd file description. let eventfd = eventfd_ref.downcast::<Event>().unwrap(); @@ -293,6 +285,7 @@ fn eventfd_read<'tcx>( eventfd.blocked_read_tid.borrow_mut().push(ecx.active_thread()); + let weak_eventfd = eventfd_ref.downgrade(); ecx.block_thread( BlockReason::Eventfd, None, @@ -303,8 +296,10 @@ fn eventfd_read<'tcx>( weak_eventfd: WeakFileDescriptionRef, } @unblock = |this| { - // When we get unblocked, try again. - eventfd_read(buf_place, &dest, weak_eventfd, this) + // When we get unblocked, try again. We know the ref is still valid, + // otherwise there couldn't be a `write` that unblocks us. + let eventfd_ref = weak_eventfd.upgrade().unwrap(); + eventfd_read(buf_place, &dest, &eventfd_ref, this) } ), ); @@ -317,7 +312,7 @@ fn eventfd_read<'tcx>( // The state changed; we check and update the status of all supported event // types for current file description. - ecx.check_and_update_readiness(&eventfd_ref)?; + ecx.check_and_update_readiness(eventfd_ref)?; // Unblock *all* threads previously blocked on `write`. // We need to take out the blocked thread ids and unblock them together, |