129 lines
3.8 KiB
Go
129 lines
3.8 KiB
Go
package sys
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import (
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"io"
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"os"
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experimentalsys "github.com/tetratelabs/wazero/experimental/sys"
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"github.com/tetratelabs/wazero/internal/fsapi"
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"github.com/tetratelabs/wazero/internal/sysfs"
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"github.com/tetratelabs/wazero/sys"
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)
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// StdinFile is a fs.ModeDevice file for use implementing FdStdin.
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// This is safer than reading from os.DevNull as it can never overrun
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// operating system file descriptors.
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type StdinFile struct {
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noopStdinFile
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io.Reader
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}
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// Read implements the same method as documented on sys.File
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func (f *StdinFile) Read(buf []byte) (int, experimentalsys.Errno) {
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n, err := f.Reader.Read(buf)
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return n, experimentalsys.UnwrapOSError(err)
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}
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type writerFile struct {
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noopStdoutFile
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w io.Writer
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}
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// Write implements the same method as documented on sys.File
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func (f *writerFile) Write(buf []byte) (int, experimentalsys.Errno) {
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n, err := f.w.Write(buf)
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return n, experimentalsys.UnwrapOSError(err)
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}
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// noopStdinFile is a fs.ModeDevice file for use implementing FdStdin. This is
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// safer than reading from os.DevNull as it can never overrun operating system
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// file descriptors.
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type noopStdinFile struct {
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noopStdioFile
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}
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// Read implements the same method as documented on sys.File
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func (noopStdinFile) Read([]byte) (int, experimentalsys.Errno) {
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return 0, 0 // Always EOF
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}
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// Poll implements the same method as documented on fsapi.File
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func (noopStdinFile) Poll(flag fsapi.Pflag, timeoutMillis int32) (ready bool, errno experimentalsys.Errno) {
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if flag != fsapi.POLLIN {
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return false, experimentalsys.ENOTSUP
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}
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return true, 0 // always ready to read nothing
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}
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// noopStdoutFile is a fs.ModeDevice file for use implementing FdStdout and
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// FdStderr.
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type noopStdoutFile struct {
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noopStdioFile
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}
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// Write implements the same method as documented on sys.File
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func (noopStdoutFile) Write(buf []byte) (int, experimentalsys.Errno) {
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return len(buf), 0 // same as io.Discard
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}
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type noopStdioFile struct {
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experimentalsys.UnimplementedFile
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}
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// Stat implements the same method as documented on sys.File
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func (noopStdioFile) Stat() (sys.Stat_t, experimentalsys.Errno) {
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return sys.Stat_t{Mode: modeDevice, Nlink: 1}, 0
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}
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// IsDir implements the same method as documented on sys.File
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func (noopStdioFile) IsDir() (bool, experimentalsys.Errno) {
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return false, 0
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}
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// Close implements the same method as documented on sys.File
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func (noopStdioFile) Close() (errno experimentalsys.Errno) { return }
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// IsNonblock implements the same method as documented on fsapi.File
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func (noopStdioFile) IsNonblock() bool {
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return false
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}
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// SetNonblock implements the same method as documented on fsapi.File
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func (noopStdioFile) SetNonblock(bool) experimentalsys.Errno {
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return experimentalsys.ENOSYS
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}
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// Poll implements the same method as documented on fsapi.File
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func (noopStdioFile) Poll(fsapi.Pflag, int32) (ready bool, errno experimentalsys.Errno) {
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return false, experimentalsys.ENOSYS
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}
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func stdinFileEntry(r io.Reader) (*FileEntry, error) {
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if r == nil {
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return &FileEntry{Name: "stdin", IsPreopen: true, File: &noopStdinFile{}}, nil
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} else if f, ok := r.(*os.File); ok {
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if f, err := sysfs.NewStdioFile(true, f); err != nil {
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return nil, err
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} else {
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return &FileEntry{Name: "stdin", IsPreopen: true, File: f}, nil
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}
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} else {
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return &FileEntry{Name: "stdin", IsPreopen: true, File: &StdinFile{Reader: r}}, nil
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}
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}
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func stdioWriterFileEntry(name string, w io.Writer) (*FileEntry, error) {
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if w == nil {
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return &FileEntry{Name: name, IsPreopen: true, File: &noopStdoutFile{}}, nil
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} else if f, ok := w.(*os.File); ok {
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if f, err := sysfs.NewStdioFile(false, f); err != nil {
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return nil, err
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} else {
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return &FileEntry{Name: name, IsPreopen: true, File: f}, nil
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}
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} else {
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return &FileEntry{Name: name, IsPreopen: true, File: &writerFile{w: w}}, nil
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}
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}
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