319d6cca62
This reduces some boilerplate by extracting UnimplementedFS from the existing FS implementations, such that it returns ENOSYS. This also removes inconsistency where some methods on FS returned syscall.Errno and others PathError. Note: this doesn't get rid of all PathError, yet. We still need to create a syscallfs.File type which would be able to do that. This is just one preliminary cleanup before refactoring out the `fs.FS` embedding from `syscallfs.DS`. P.S. naming convention is arbitrary, so I took UnimplementedXXX from grpc. This pattern is used a lot of places, also proxy-wasm-go-sdk, e.g. `DefaultVMContext`. Signed-off-by: Adrian Cole <adrian@tetrate.io>
127 lines
3.1 KiB
Go
127 lines
3.1 KiB
Go
package syscallfs
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import (
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"errors"
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"io"
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"io/fs"
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"os"
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"syscall"
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)
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// See https://learn.microsoft.com/en-us/windows/win32/debug/system-error-codes--0-499-
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const (
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// ERROR_ACCESS_DENIED is a Windows error returned by syscall.Unlink
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// instead of syscall.EPERM
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ERROR_ACCESS_DENIED = syscall.Errno(5)
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// ERROR_INVALID_HANDLE is a Windows error returned by syscall.Write
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// instead of syscall.EBADF
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ERROR_INVALID_HANDLE = syscall.Errno(6)
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// ERROR_ALREADY_EXISTS is a Windows error returned by os.Mkdir
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// instead of syscall.EEXIST
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ERROR_ALREADY_EXISTS = syscall.Errno(183)
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// ERROR_DIRECTORY is a Windows error returned by syscall.Rmdir
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// instead of syscall.ENOTDIR
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ERROR_DIRECTORY = syscall.Errno(267)
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// ERROR_DIR_NOT_EMPTY is a Windows error returned by syscall.Rmdir
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// instead of syscall.ENOTEMPTY
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ERROR_DIR_NOT_EMPTY = syscall.Errno(145)
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)
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func adjustMkdirError(err error) error {
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if err == ERROR_ALREADY_EXISTS {
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return syscall.EEXIST
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}
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return err
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}
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func adjustRmdirError(err error) error {
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switch err {
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case ERROR_DIRECTORY:
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return syscall.ENOTDIR
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case ERROR_DIR_NOT_EMPTY:
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return syscall.ENOTEMPTY
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}
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return err
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}
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func adjustUnlinkError(err error) error {
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if err == ERROR_ACCESS_DENIED {
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return syscall.EISDIR
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}
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return err
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}
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// rename uses os.Rename as `windows.Rename` is internal in Go's source tree.
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func rename(old, new string) (err error) {
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if err = os.Rename(old, new); err == nil {
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return
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}
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err = errors.Unwrap(err) // unwrap the link error
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if err == ERROR_ACCESS_DENIED {
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var newIsDir bool
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if stat, statErr := os.Stat(new); statErr == nil && stat.IsDir() {
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newIsDir = true
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}
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var oldIsDir bool
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if stat, statErr := os.Stat(old); statErr == nil && stat.IsDir() {
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oldIsDir = true
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}
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if oldIsDir && newIsDir {
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// Windows doesn't let you overwrite a directory. If we aim to
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// allow this, we'll have to delete here and retry.
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return syscall.EINVAL
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} else if newIsDir {
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err = syscall.EISDIR
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} else { // use a mappable code
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err = syscall.EPERM
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}
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}
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return
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}
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// maybeWrapFile deals with errno portability issues in Windows. This code is
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// likely to change as we complete syscall support needed for WASI and GOOS=js.
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//
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// If we don't map to syscall.Errno, wasm will crash in odd way attempting the
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// same. This approach is an alternative to making our own fs.File public type.
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// We aren't doing that yet, as mapping problems are generally contained to
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// Windows. Hence, file is intentionally not exported.
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func maybeWrapFile(f file) file {
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return struct {
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readFile
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io.Writer
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io.WriterAt // for pwrite
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syncer
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}{f, &windowsWriter{f}, f, f}
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}
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// windowsWriter translates error codes not mapped properly by Go.
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type windowsWriter struct {
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w io.Writer
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}
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// Write implements io.Writer
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func (w windowsWriter) Write(p []byte) (n int, err error) {
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n, err = w.w.Write(p)
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if err == nil {
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return
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}
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// os.File.Wrap wraps the syscall error in a path error
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if pe, ok := err.(*fs.PathError); ok {
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switch pe.Err {
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case ERROR_INVALID_HANDLE:
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pe.Err = syscall.EBADF
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case ERROR_ACCESS_DENIED:
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pe.Err = syscall.EPERM
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}
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}
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return
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}
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