ioctl/mmap: do not panic if provided length is zero

Return an error instead, as this is a public API which shouldn't panic if provided an invalid input.
lu-zero · Sep 5, 2023 · 0c7db64 · 0c7db64
1 parent 6a01170
commit 0c7db64
Showing 1 changed file with 4 additions and 1 deletion.
diff --git a/lib/src/ioctl/mmap.rs b/lib/src/ioctl/mmap.rs
@@ -75,13 +75,16 @@ impl Drop for PlaneMapping {
 
 #[derive(Debug, Error)]
 pub enum MmapError {
+    #[error("provided length was 0")]
+    ZeroLength,
     #[error("ioctl error: {0}")]
     IoctlError(#[from] Errno),
 }
 
 impl From<MmapError> for Errno {
     fn from(err: MmapError) -> Self {
         match err {
+            MmapError::ZeroLength => Errno::EINVAL,
             MmapError::IoctlError(e) => e,
         }
     }
@@ -90,7 +93,7 @@ impl From<MmapError> for Errno {
 // TODO should be unsafe because the mapping can be used after a buffer is queued?
 // Or not, since this cannot cause a crash...
 pub fn mmap(fd: &impl AsFd, mem_offset: u32, length: u32) -> Result<PlaneMapping, MmapError> {
-    let non_zero_length = NonZeroUsize::new(length as usize).unwrap();
+    let non_zero_length = NonZeroUsize::new(length as usize).ok_or(MmapError::ZeroLength)?;
     let data = unsafe {
         mman::mmap(
             None,