GoToSocial/vendor/github.com/tetratelabs/wazero/internal/sysfs/osfile.go

296 lines
8.4 KiB
Go
Raw Normal View History

package sysfs
import (
"io"
"io/fs"
"os"
"runtime"
experimentalsys "github.com/tetratelabs/wazero/experimental/sys"
"github.com/tetratelabs/wazero/internal/fsapi"
"github.com/tetratelabs/wazero/sys"
)
func newOsFile(path string, flag experimentalsys.Oflag, perm fs.FileMode, f *os.File) fsapi.File {
// Windows cannot read files written to a directory after it was opened.
// This was noticed in #1087 in zig tests. Use a flag instead of a
// different type.
reopenDir := runtime.GOOS == "windows"
return &osFile{path: path, flag: flag, perm: perm, reopenDir: reopenDir, file: f, fd: f.Fd()}
}
// osFile is a file opened with this package, and uses os.File or syscalls to
// implement api.File.
type osFile struct {
path string
flag experimentalsys.Oflag
perm fs.FileMode
file *os.File
fd uintptr
// reopenDir is true if reopen should be called before Readdir. This flag
// is deferred until Readdir to prevent redundant rewinds. This could
// happen if Seek(0) was called twice, or if in Windows, Seek(0) was called
// before Readdir.
reopenDir bool
// closed is true when closed was called. This ensures proper sys.EBADF
closed bool
// cachedStat includes fields that won't change while a file is open.
cachedSt *cachedStat
}
// cachedStat returns the cacheable parts of sys.Stat_t or an error if they
// couldn't be retrieved.
func (f *osFile) cachedStat() (dev uint64, ino sys.Inode, isDir bool, errno experimentalsys.Errno) {
if f.cachedSt == nil {
if _, errno = f.Stat(); errno != 0 {
return
}
}
return f.cachedSt.dev, f.cachedSt.ino, f.cachedSt.isDir, 0
}
// Dev implements the same method as documented on sys.File
func (f *osFile) Dev() (uint64, experimentalsys.Errno) {
dev, _, _, errno := f.cachedStat()
return dev, errno
}
// Ino implements the same method as documented on sys.File
func (f *osFile) Ino() (sys.Inode, experimentalsys.Errno) {
_, ino, _, errno := f.cachedStat()
return ino, errno
}
// IsDir implements the same method as documented on sys.File
func (f *osFile) IsDir() (bool, experimentalsys.Errno) {
_, _, isDir, errno := f.cachedStat()
return isDir, errno
}
// IsAppend implements File.IsAppend
func (f *osFile) IsAppend() bool {
return f.flag&experimentalsys.O_APPEND == experimentalsys.O_APPEND
}
// SetAppend implements the same method as documented on sys.File
func (f *osFile) SetAppend(enable bool) (errno experimentalsys.Errno) {
if enable {
f.flag |= experimentalsys.O_APPEND
} else {
f.flag &= ^experimentalsys.O_APPEND
}
// Clear any create or trunc flag, as we are re-opening, not re-creating.
f.flag &= ^(experimentalsys.O_CREAT | experimentalsys.O_TRUNC)
// appendMode (bool) cannot be changed later, so we have to re-open the
// file. https://github.com/golang/go/blob/go1.20/src/os/file_unix.go#L60
return fileError(f, f.closed, f.reopen())
}
// compile-time check to ensure osFile.reopen implements reopenFile.
var _ reopenFile = (*osFile)(nil).reopen
func (f *osFile) reopen() (errno experimentalsys.Errno) {
// Clear any create flag, as we are re-opening, not re-creating.
f.flag &= ^experimentalsys.O_CREAT
var (
isDir bool
offset int64
err error
)
isDir, errno = f.IsDir()
if errno != 0 {
return errno
}
if !isDir {
offset, err = f.file.Seek(0, io.SeekCurrent)
if err != nil {
return experimentalsys.UnwrapOSError(err)
}
}
_ = f.close()
f.file, errno = OpenFile(f.path, f.flag, f.perm)
if errno != 0 {
return errno
}
if !isDir {
_, err = f.file.Seek(offset, io.SeekStart)
if err != nil {
return experimentalsys.UnwrapOSError(err)
}
}
return 0
}
// IsNonblock implements the same method as documented on fsapi.File
func (f *osFile) IsNonblock() bool {
return isNonblock(f)
}
// SetNonblock implements the same method as documented on fsapi.File
func (f *osFile) SetNonblock(enable bool) (errno experimentalsys.Errno) {
if enable {
f.flag |= experimentalsys.O_NONBLOCK
} else {
f.flag &= ^experimentalsys.O_NONBLOCK
}
if errno = setNonblock(f.fd, enable); errno != 0 {
return fileError(f, f.closed, errno)
}
return 0
}
// Stat implements the same method as documented on sys.File
func (f *osFile) Stat() (sys.Stat_t, experimentalsys.Errno) {
if f.closed {
return sys.Stat_t{}, experimentalsys.EBADF
}
st, errno := statFile(f.file)
switch errno {
case 0:
f.cachedSt = &cachedStat{dev: st.Dev, ino: st.Ino, isDir: st.Mode&fs.ModeDir == fs.ModeDir}
case experimentalsys.EIO:
errno = experimentalsys.EBADF
}
return st, errno
}
// Read implements the same method as documented on sys.File
func (f *osFile) Read(buf []byte) (n int, errno experimentalsys.Errno) {
if len(buf) == 0 {
return 0, 0 // Short-circuit 0-len reads.
}
if nonBlockingFileReadSupported && f.IsNonblock() {
n, errno = readFd(f.fd, buf)
} else {
n, errno = read(f.file, buf)
}
if errno != 0 {
// Defer validation overhead until we've already had an error.
errno = fileError(f, f.closed, errno)
}
return
}
// Pread implements the same method as documented on sys.File
func (f *osFile) Pread(buf []byte, off int64) (n int, errno experimentalsys.Errno) {
if n, errno = pread(f.file, buf, off); errno != 0 {
// Defer validation overhead until we've already had an error.
errno = fileError(f, f.closed, errno)
}
return
}
// Seek implements the same method as documented on sys.File
func (f *osFile) Seek(offset int64, whence int) (newOffset int64, errno experimentalsys.Errno) {
if newOffset, errno = seek(f.file, offset, whence); errno != 0 {
// Defer validation overhead until we've already had an error.
errno = fileError(f, f.closed, errno)
// If the error was trying to rewind a directory, re-open it. Notably,
// seeking to zero on a directory doesn't work on Windows with Go 1.19.
if errno == experimentalsys.EISDIR && offset == 0 && whence == io.SeekStart {
errno = 0
f.reopenDir = true
}
}
return
}
// Poll implements the same method as documented on fsapi.File
func (f *osFile) Poll(flag fsapi.Pflag, timeoutMillis int32) (ready bool, errno experimentalsys.Errno) {
return poll(f.fd, flag, timeoutMillis)
}
// Readdir implements File.Readdir. Notably, this uses "Readdir", not
// "ReadDir", from os.File.
func (f *osFile) Readdir(n int) (dirents []experimentalsys.Dirent, errno experimentalsys.Errno) {
if f.reopenDir { // re-open the directory if needed.
f.reopenDir = false
if errno = adjustReaddirErr(f, f.closed, f.reopen()); errno != 0 {
return
}
}
if dirents, errno = readdir(f.file, f.path, n); errno != 0 {
errno = adjustReaddirErr(f, f.closed, errno)
}
return
}
// Write implements the same method as documented on sys.File
func (f *osFile) Write(buf []byte) (n int, errno experimentalsys.Errno) {
if len(buf) == 0 {
return 0, 0 // Short-circuit 0-len writes.
}
if nonBlockingFileWriteSupported && f.IsNonblock() {
n, errno = writeFd(f.fd, buf)
} else if n, errno = write(f.file, buf); errno != 0 {
// Defer validation overhead until we've already had an error.
errno = fileError(f, f.closed, errno)
}
return
}
// Pwrite implements the same method as documented on sys.File
func (f *osFile) Pwrite(buf []byte, off int64) (n int, errno experimentalsys.Errno) {
if n, errno = pwrite(f.file, buf, off); errno != 0 {
// Defer validation overhead until we've already had an error.
errno = fileError(f, f.closed, errno)
}
return
}
// Truncate implements the same method as documented on sys.File
func (f *osFile) Truncate(size int64) (errno experimentalsys.Errno) {
if errno = experimentalsys.UnwrapOSError(f.file.Truncate(size)); errno != 0 {
// Defer validation overhead until we've already had an error.
errno = fileError(f, f.closed, errno)
}
return
}
// Sync implements the same method as documented on sys.File
func (f *osFile) Sync() experimentalsys.Errno {
return fsync(f.file)
}
// Datasync implements the same method as documented on sys.File
func (f *osFile) Datasync() experimentalsys.Errno {
return datasync(f.file)
}
// Utimens implements the same method as documented on sys.File
func (f *osFile) Utimens(atim, mtim int64) experimentalsys.Errno {
if f.closed {
return experimentalsys.EBADF
}
err := futimens(f.fd, atim, mtim)
return experimentalsys.UnwrapOSError(err)
}
// Close implements the same method as documented on sys.File
func (f *osFile) Close() experimentalsys.Errno {
if f.closed {
return 0
}
f.closed = true
return f.close()
}
func (f *osFile) close() experimentalsys.Errno {
return experimentalsys.UnwrapOSError(f.file.Close())
}