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Author: tiif

src/shims/unix/linux/eventfd.rs

@@ -9,6 +9,9 @@ use crate::{concurrency::VClock, *};
 
 use self::shims::unix::fd::FileDescriptor;
 
+/// Minimum size of u8 array to hold u64 value.
+const U64_MIN_ARRAY_SIZE: usize = 8;
+
 /// Maximum value that the eventfd counter can hold.
 const MAX_COUNTER: u64 = u64::MAX - 1;
 
@@ -48,7 +51,7 @@ impl FileDescription for Event {
         ecx: &mut MiriInterpCx<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         // Check the size of slice, and return error only if the size of the slice < 8.
-        let Some(bytes) = bytes.first_chunk_mut::<8>() else {
+        let Some(bytes) = bytes.first_chunk_mut::<U64_MIN_ARRAY_SIZE>() else {
             return Ok(Err(Error::from(ErrorKind::InvalidInput)));
         };
         // Block when counter == 0.
@@ -68,7 +71,7 @@ impl FileDescription for Event {
                 Endian::Big => self.counter.to_be_bytes(),
             };
             self.counter = 0;
-            return Ok(Ok(8));
+            return Ok(Ok(U64_MIN_ARRAY_SIZE));
         }
     }
 
@@ -91,7 +94,7 @@ impl FileDescription for Event {
         ecx: &mut MiriInterpCx<'tcx>,
     ) -> InterpResult<'tcx, io::Result<usize>> {
         // Check the size of slice, and return error only if the size of the slice < 8.
-        let Some(bytes) = bytes.first_chunk::<8>() else {
+        let Some(bytes) = bytes.first_chunk::<U64_MIN_ARRAY_SIZE>() else {
             return Ok(Err(Error::from(ErrorKind::InvalidInput)));
         };
         // Convert from bytes to int according to host endianness.
@@ -120,7 +123,7 @@ impl FileDescription for Event {
                 }
             }
         };
-        Ok(Ok(8))
+        Ok(Ok(U64_MIN_ARRAY_SIZE))
     }
 }
 
@@ -161,14 +164,14 @@ pub trait EvalContextExt<'tcx>: crate::MiriInterpCxExt<'tcx> {
 
         let mut is_nonblock = false;
         // Unload the flag that we support.
+        // After unloading, flags != 0 means other flags are used.
         if flags & efd_cloexec == efd_cloexec {
             flags &= !efd_cloexec;
         }
         if flags & efd_nonblock == efd_nonblock {
             flags &= !efd_nonblock;
             is_nonblock = true;
         }
-        // After unloading, flags != 0 means other flags are used.
         if flags != 0 {
             let einval = this.eval_libc("EINVAL");
             this.set_last_error(einval)?;

tests/fail-dep/libc/libc_eventfd_read_block.rs

@@ -1,7 +1,7 @@
 //@ignore-target-windows: No eventfd on Windows
 //@ignore-target-apple: No eventfd in macos
 fn main() {
-    // eventfd read will block when non-block flag is clear and counter = 0.
+    // eventfd read will block when EFD_NONBLOCK flag is clear and counter = 0.
     // This will pass when blocking is implemented.
     let flags = libc::EFD_CLOEXEC;
     let fd = unsafe { libc::eventfd(0, flags) };

tests/fail-dep/libc/libc_eventfd_write_block.rs

@@ -1,7 +1,7 @@
 //@ignore-target-windows: No eventfd on Windows
 //@ignore-target-apple: No eventfd in macos
 fn main() {
-    // eventfd write will block when we try to add until it exceed u64-1.
+    // eventfd write will block when we try to add until it exceed u64::MAX - 1.
     // This will pass when blocking is implemented.
     let flags = libc::EFD_CLOEXEC;
     let fd = unsafe { libc::eventfd(0, flags) };