Improve error code on RTEMS OS_stat() implementation

[jphickey]

Is your feature request related to a problem? Please describe.
Depending on the filesystem in use, the RTEMS statvfs() call might not be implemented at the filesystem level. In particular if it is called on the IMFS filesystem type, it returns an error and sets errno to ENOSYS.

OSAL translates any error here to OS_ERROR, which is what gets returned to the application.

Ultimately this causes the filesystem unit test to fail when this filesystem type is in use.

Describe the solution you'd like
Preferable to return OS_ERR_NOT_IMPLEMENTED in this case. In particular, unit tests already check for this, and will skip the test cases for this API, avoiding failure. This makes it a soft error.

Requester Info
Joseph Hickey, Vantage Systems, Inc.

[joelsherrill]

Alternatively, you could implement statvfs() for the IMFS. RTEMS is open source and encourages submissions.</shameless hint> :)

[jphickey]

Alternatively, you could implement statvfs() for the IMFS. RTEMS is open source and encourages submissions.</shameless hint> :)

I think maybe the reason its not implemented is because IMFS is dynamically sized, so there isn't a predefined limit for the total size of this FS.

Still, the ENOSYS errno should logically translate to OS_ERR_NOT_IMPLEMENTED either way, as this is basically what it means.