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fix io::copy specialization when writer was opened with O_APPEND

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This commit is contained in:
The8472 2021-02-22 21:18:12 +01:00
parent 5c0d76dbe1
commit 81602fb670
1 changed files with 10 additions and 8 deletions
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18
library/std/src/sys/unix/kernel_copy.rs
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@ -61,6 +61,7 @@ use crate::process::{ChildStderr, ChildStdin, ChildStdout};
use crate::ptr;
use crate::sync::atomic::{AtomicBool, AtomicU8, Ordering};
use crate::sys::cvt;
use libc::{EBADF, EINVAL, ENOSYS, EOPNOTSUPP, EOVERFLOW, EPERM, EXDEV};
#[cfg(test)]
mod tests;
@ -535,7 +536,7 @@ pub(super) fn copy_regular_files(reader: RawFd, writer: RawFd, max_len: u64) ->
cvt(copy_file_range(INVALID_FD, ptr::null_mut(), INVALID_FD, ptr::null_mut(), 1, 0))
};
if matches!(result.map_err(|e| e.raw_os_error()), Err(Some(libc::EBADF))) {
if matches!(result.map_err(|e| e.raw_os_error()), Err(Some(EBADF))) {
HAS_COPY_FILE_RANGE.store(AVAILABLE, Ordering::Relaxed);
} else {
HAS_COPY_FILE_RANGE.store(UNAVAILABLE, Ordering::Relaxed);
@ -573,19 +574,20 @@ pub(super) fn copy_regular_files(reader: RawFd, writer: RawFd, max_len: u64) ->
Err(err) => {
return match err.raw_os_error() {
// when file offset + max_length > u64::MAX
Some(libc::EOVERFLOW) => CopyResult::Fallback(written),
Some(
libc::ENOSYS | libc::EXDEV | libc::EINVAL | libc::EPERM | libc::EOPNOTSUPP,
) => {
Some(EOVERFLOW) => CopyResult::Fallback(written),
Some(ENOSYS | EXDEV | EINVAL | EPERM | EOPNOTSUPP | EBADF) => {
// 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)
//
// 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)
}
@ -649,7 +651,7 @@ fn sendfile_splice(mode: SpliceMode, reader: RawFd, writer: RawFd, len: u64) ->
Ok(ret) => written += ret as u64,
Err(err) => {
return match err.raw_os_error() {
Some(libc::ENOSYS | libc::EPERM) => {
Some(ENOSYS | EPERM) => {
// syscall not supported (ENOSYS)
// syscall is disallowed, e.g. by seccomp (EPERM)
match mode {
@ -659,12 +661,12 @@ fn sendfile_splice(mode: SpliceMode, reader: RawFd, writer: RawFd, len: u64) ->
assert_eq!(written, 0);
CopyResult::Fallback(0)
}
Some(libc::EINVAL) => {
Some(EINVAL) => {
// splice/sendfile do not support this particular file descriptor (EINVAL)
assert_eq!(written, 0);
CopyResult::Fallback(0)
}
Some(os_err) if mode == SpliceMode::Sendfile && os_err == libc::EOVERFLOW => {
Some(os_err) if mode == SpliceMode::Sendfile && os_err == EOVERFLOW => {
CopyResult::Fallback(written)
}
_ => CopyResult::Error(err, written),