[GitHub] [incubator-nuttx] gustavonihei commented on a change in pull request #3070: fs/mmap: Return EACCES for incompatible file descriptors

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gustavonihei commented on a change in pull request #3070:
URL: https://github.com/apache/incubator-nuttx/pull/3070#discussion_r595071043



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File path: fs/mmap/fs_mmap.c
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@@ -142,6 +148,30 @@ FAR void *mmap(FAR void *start, size_t length, int prot, int flags,
     }
 #endif
 
+  if (fs_getfilep(fd, &filep) < 0)

Review comment:
       `fs_getfilep` either returns **-EBADF** or **-EAGAIN**.
   According to the `mmap` specification, although EAGAIN is a possible return value, it is useful for indicating that a file is currently locked and the API user should try `mmap` again later.
   But, `fs_getfilep` returns **-EAGAIN** for a unrecoverable error scenario:
   
   ![image](https://user-images.githubusercontent.com/38959758/111299708-07f4ca00-862f-11eb-8765-3fe71e92c48d.png)
   
   So, I think it does not make sense to simply make `mmap` propagate the error from `fs_getfilep`. Instead, I chose to handle the error and raise a new one that fits to `mmap` API.




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