Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

kernel_copy: avoid panic on unexpected OS error #91153

Merged
merged 1 commit into from
Nov 23, 2021
Merged

kernel_copy: avoid panic on unexpected OS error #91153

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 4 additions & 2 deletions library/std/src/sys/unix/kernel_copy.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -576,20 +576,22 @@ pub(super) fn copy_regular_files(reader: RawFd, writer: RawFd, max_len: u64) ->
return match err.raw_os_error() {
// when file offset + max_length > u64::MAX
Some(EOVERFLOW) => CopyResult::Fallback(written),
Some(ENOSYS | EXDEV | EINVAL | EPERM | EOPNOTSUPP | EBADF) => {
Some(ENOSYS | EXDEV | EINVAL | EPERM | EOPNOTSUPP | EBADF) if written == 0 => {
// Try fallback io::copy if either:
// - Kernel version is < 4.5 (ENOSYS¹)
// - Files are mounted on different fs (EXDEV)
// - copy_file_range is broken in various ways on RHEL/CentOS 7 (EOPNOTSUPP)
// - copy_file_range file is immutable or syscall is blocked by seccomp¹ (EPERM)
// - copy_file_range cannot be used with pipes or device nodes (EINVAL)
// - the writer fd was opened with O_APPEND (EBADF²)
// and no bytes were written successfully yet. (All these errnos should
// not be returned if something was already written, but they happen in
// the wild, see #91152.)
//
// ¹ these cases should be detected by the initial probe but we handle them here
// anyway in case syscall interception changes during runtime
// ² actually invalid file descriptors would cause this too, but in that case
// the fallback code path is expected to encounter the same error again
assert_eq!(written, 0);
CopyResult::Fallback(0)
}
_ => CopyResult::Error(err, written),
Expand Down