Be stricter with copy_file_range probe results · model-checking/verify-rust-std@30c876c (original) (raw)
`@@ -607,42 +607,44 @@ pub(super) fn copy_regular_files(reader: RawFd, writer: RawFd, max_len: u64) ->
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`Ok(0) => return CopyResult::Ended(written), // reached EOF
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`Ok(ret) => written += ret as u64,
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`Err(err) => {
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``
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let raw_os_error = match err.raw_os_error() {
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Some(raw) => raw,
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_ => return CopyResult::Error(err, written),
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};
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return match raw_os_error {
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return match err.raw_os_error() {
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`// when file offset + max_length > u64::MAX
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``
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EOVERFLOW => CopyResult::Fallback(written),
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ENOSYS | EXDEV | EINVAL | EPERM | EOPNOTSUPP | EBADF if written == 0 => {
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Some(EOVERFLOW) => CopyResult::Fallback(written),
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Some(raw_os_error @ (ENOSYS | EXDEV | EINVAL | EPERM | EOPNOTSUPP | EBADF))
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if written == 0 =>
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{
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`if !have_probed {
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if raw_os_error == ENOSYS {
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HAS_COPY_FILE_RANGE.store(UNAVAILABLE, Ordering::Relaxed);
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} else {
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// EPERM can indicate seccomp filters or an
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// immutable file. To distinguish these cases
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// we probe with invalid file descriptors which
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// should result in EBADF if the syscall is
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// supported and some other error (ENOSYS or
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// EPERM) if it's not available.
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let result = unsafe {
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cvt(copy_file_range(
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INVALID_FD,
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ptr::null_mut(),
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INVALID_FD,
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ptr::null_mut(),
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1,
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0,
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))
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};
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if matches!(result.map_err(|e| e.raw_os_error()), Err(Some(EBADF)))
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{
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HAS_COPY_FILE_RANGE.store(AVAILABLE, Ordering::Relaxed);
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} else {
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HAS_COPY_FILE_RANGE.store(UNAVAILABLE, Ordering::Relaxed);
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let available = match raw_os_error {
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EPERM => {
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// EPERM can indicate seccomp filters or an
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// immutable file. To distinguish these
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// cases we probe with invalid file
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// descriptors which should result in EBADF
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// if the syscall is supported and EPERM or
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// ENOSYS if it's not available.
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match unsafe {
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cvt(copy_file_range(
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INVALID_FD,
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ptr::null_mut(),
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INVALID_FD,
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ptr::null_mut(),
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1,
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0,
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))
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.map_err(|e| e.raw_os_error())
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} {
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Err(Some(EPERM | ENOSYS)) => UNAVAILABLE,
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Err(Some(EBADF)) => AVAILABLE,
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Ok(_) => panic!("unexpected copy_file_range probe success"),
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// Treat other errors as the syscall
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// being unavailable.
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Err(_) => UNAVAILABLE,
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}
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`}
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}
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ENOSYS => UNAVAILABLE,
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_ => AVAILABLE,
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};
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HAS_COPY_FILE_RANGE.store(available, Ordering::Relaxed);
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`}
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``
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`// Try fallback io::copy if either:
`