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Diffstat (limited to 'runsc/fsgofer/fsgofer.go')
-rw-r--r--runsc/fsgofer/fsgofer.go534
1 files changed, 287 insertions, 247 deletions
diff --git a/runsc/fsgofer/fsgofer.go b/runsc/fsgofer/fsgofer.go
index 74977c313..0b628c8ce 100644
--- a/runsc/fsgofer/fsgofer.go
+++ b/runsc/fsgofer/fsgofer.go
@@ -29,7 +29,6 @@ import (
"path/filepath"
"runtime"
"strconv"
- "syscall"
"golang.org/x/sys/unix"
"gvisor.dev/gvisor/pkg/abi/linux"
@@ -45,39 +44,11 @@ const (
// modes to ensure an unopened/closed file fails all mode checks.
invalidMode = p9.OpenFlags(math.MaxUint32)
- openFlags = syscall.O_NOFOLLOW | syscall.O_CLOEXEC
-)
-
-type fileType int
+ openFlags = unix.O_NOFOLLOW | unix.O_CLOEXEC
-const (
- regular fileType = iota
- directory
- symlink
- socket
- unknown
+ allowedOpenFlags = unix.O_TRUNC
)
-// String implements fmt.Stringer.
-func (f fileType) String() string {
- switch f {
- case regular:
- return "regular"
- case directory:
- return "directory"
- case symlink:
- return "symlink"
- case socket:
- return "socket"
- }
- return "unknown"
-}
-
-// ControlSocketAddr generates an abstract unix socket name for the given id.
-func ControlSocketAddr(id string) string {
- return fmt.Sprintf("\x00runsc-gofer.%s", id)
-}
-
// Config sets configuration options for each attach point.
type Config struct {
// ROMount is set to true if this is a readonly mount.
@@ -132,19 +103,19 @@ func (a *attachPoint) Attach() (p9.File, error) {
return nil, fmt.Errorf("attach point already attached, prefix: %s", a.prefix)
}
- f, err := openAnyFile(a.prefix, func(mode int) (*fd.FD, error) {
+ f, readable, err := openAnyFile(a.prefix, func(mode int) (*fd.FD, error) {
return fd.Open(a.prefix, openFlags|mode, 0)
})
if err != nil {
return nil, fmt.Errorf("unable to open %q: %v", a.prefix, err)
}
- stat, err := stat(f.FD())
+ stat, err := fstat(f.FD())
if err != nil {
return nil, fmt.Errorf("unable to stat %q: %v", a.prefix, err)
}
- lf, err := newLocalFile(a, f, a.prefix, stat)
+ lf, err := newLocalFile(a, f, a.prefix, readable, stat)
if err != nil {
return nil, fmt.Errorf("unable to create localFile %q: %v", a.prefix, err)
}
@@ -153,7 +124,7 @@ func (a *attachPoint) Attach() (p9.File, error) {
}
// makeQID returns a unique QID for the given stat buffer.
-func (a *attachPoint) makeQID(stat syscall.Stat_t) p9.QID {
+func (a *attachPoint) makeQID(stat unix.Stat_t) p9.QID {
a.deviceMu.Lock()
defer a.deviceMu.Unlock()
@@ -184,9 +155,7 @@ func (a *attachPoint) makeQID(stat syscall.Stat_t) p9.QID {
// localFile implements p9.File wrapping a local file. The underlying file
// is opened during Walk() and stored in 'file' to be used with other
// operations. The file is opened as readonly, unless it's a symlink or there is
-// no read access, which requires O_PATH. 'file' is dup'ed when Walk(nil) is
-// called to clone the file. This reduces the number of walks that need to be
-// done by the host file system when files are reused.
+// no read access, which requires O_PATH.
//
// The file may be reopened if the requested mode in Open() is not a subset of
// current mode. Consequently, 'file' could have a mode wider than requested and
@@ -198,13 +167,30 @@ func (a *attachPoint) makeQID(stat syscall.Stat_t) p9.QID {
// performance with 'overlay2' storage driver. overlay2 eagerly copies the
// entire file up when it's opened in write mode, and would perform badly when
// multiple files are only being opened for read (esp. startup).
+//
+// File operations must use "at" functions whenever possible:
+// * Local operations must use AT_EMPTY_PATH:
+// fchownat(fd, "", AT_EMPTY_PATH, ...), instead of chown(fullpath, ...)
+// * Creation operations must use (fd + name):
+// mkdirat(fd, name, ...), instead of mkdir(fullpath, ...)
+//
+// Apart from being faster, it also adds another layer of defense against
+// symlink attacks (note that O_NOFOLLOW applies only to the last element in
+// the path).
+//
+// The few exceptions where it cannot be done are: utimensat on symlinks, and
+// Connect() for the socket address.
type localFile struct {
- p9.DefaultWalkGetAttr
+ p9.DisallowClientCalls
// attachPoint is the attachPoint that serves this localFile.
attachPoint *attachPoint
- // hostPath will be safely updated by the Renamed hook.
+ // hostPath is the full path to the host file. It can be used for logging and
+ // the few cases where full path is required to operation the host file. In
+ // all other cases, use "file" directly.
+ //
+ // Note: it's safely updated by the Renamed hook.
hostPath string
// file is opened when localFile is created and it's never nil. It may be
@@ -212,12 +198,19 @@ type localFile struct {
// opened with.
file *fd.FD
+ // controlReadable tells whether 'file' was opened with read permissions
+ // during a walk.
+ controlReadable bool
+
// mode is the mode in which the file was opened. Set to invalidMode
// if localFile isn't opened.
mode p9.OpenFlags
- // ft is the fileType for this file.
- ft fileType
+ // fileType for this file. It is equivalent to:
+ // unix.Stat_t.Mode & unix.S_IFMT
+ fileType uint32
+
+ qid p9.QID
// readDirMu protects against concurrent Readdir calls.
readDirMu sync.Mutex
@@ -234,7 +227,7 @@ var procSelfFD *fd.FD
// OpenProcSelfFD opens the /proc/self/fd directory, which will be used to
// reopen file descriptors.
func OpenProcSelfFD() error {
- d, err := syscall.Open("/proc/self/fd", syscall.O_RDONLY|syscall.O_DIRECTORY, 0)
+ d, err := unix.Open("/proc/self/fd", unix.O_RDONLY|unix.O_DIRECTORY, 0)
if err != nil {
return fmt.Errorf("error opening /proc/self/fd: %v", err)
}
@@ -243,7 +236,7 @@ func OpenProcSelfFD() error {
}
func reopenProcFd(f *fd.FD, mode int) (*fd.FD, error) {
- d, err := syscall.Openat(int(procSelfFD.FD()), strconv.Itoa(f.FD()), mode&^syscall.O_NOFOLLOW, 0)
+ d, err := unix.Openat(int(procSelfFD.FD()), strconv.Itoa(f.FD()), mode&^unix.O_NOFOLLOW, 0)
if err != nil {
return nil, err
}
@@ -251,83 +244,88 @@ func reopenProcFd(f *fd.FD, mode int) (*fd.FD, error) {
return fd.New(d), nil
}
-func openAnyFileFromParent(parent *localFile, name string) (*fd.FD, string, error) {
- path := path.Join(parent.hostPath, name)
- f, err := openAnyFile(path, func(mode int) (*fd.FD, error) {
+func openAnyFileFromParent(parent *localFile, name string) (*fd.FD, string, bool, error) {
+ pathDebug := path.Join(parent.hostPath, name)
+ f, readable, err := openAnyFile(pathDebug, func(mode int) (*fd.FD, error) {
return fd.OpenAt(parent.file, name, openFlags|mode, 0)
})
- return f, path, err
+ return f, pathDebug, readable, err
}
-// openAnyFile attempts to open the file in O_RDONLY and if it fails fallsback
+// openAnyFile attempts to open the file in O_RDONLY. If it fails, falls back
// to O_PATH. 'path' is used for logging messages only. 'fn' is what does the
// actual file open and is customizable by the caller.
-func openAnyFile(path string, fn func(mode int) (*fd.FD, error)) (*fd.FD, error) {
+func openAnyFile(pathDebug string, fn func(mode int) (*fd.FD, error)) (*fd.FD, bool, error) {
// Attempt to open file in the following mode in order:
// 1. RDONLY | NONBLOCK: for all files, directories, ro mounts, FIFOs.
// Use non-blocking to prevent getting stuck inside open(2) for
// FIFOs. This option has no effect on regular files.
// 2. PATH: for symlinks, sockets.
- modes := []int{syscall.O_RDONLY | syscall.O_NONBLOCK, unix.O_PATH}
+ options := []struct {
+ mode int
+ readable bool
+ }{
+ {
+ mode: unix.O_RDONLY | unix.O_NONBLOCK,
+ readable: true,
+ },
+ {
+ mode: unix.O_PATH,
+ readable: false,
+ },
+ }
var err error
- var file *fd.FD
- for i, mode := range modes {
- file, err = fn(mode)
+ for i, option := range options {
+ var file *fd.FD
+ file, err = fn(option.mode)
if err == nil {
- // openat succeeded, we're done.
- break
+ // Succeeded opening the file, we're done.
+ return file, option.readable, nil
}
switch e := extractErrno(err); e {
- case syscall.ENOENT:
+ case unix.ENOENT:
// File doesn't exist, no point in retrying.
- return nil, e
+ return nil, false, e
}
- // openat failed. Try again with next mode, preserving 'err' in case this
- // was the last attempt.
- log.Debugf("Attempt %d to open file failed, mode: %#x, path: %q, err: %v", i, openFlags|mode, path, err)
+ // File failed to open. Try again with next mode, preserving 'err' in case
+ // this was the last attempt.
+ log.Debugf("Attempt %d to open file failed, mode: %#x, path: %q, err: %v", i, openFlags|option.mode, pathDebug, err)
}
- if err != nil {
- // All attempts to open file have failed, return the last error.
- log.Debugf("Failed to open file, path: %q, err: %v", path, err)
- return nil, extractErrno(err)
- }
-
- return file, nil
+ // All attempts to open file have failed, return the last error.
+ log.Debugf("Failed to open file, path: %q, err: %v", pathDebug, err)
+ return nil, false, extractErrno(err)
}
-func getSupportedFileType(stat syscall.Stat_t, permitSocket bool) (fileType, error) {
- var ft fileType
- switch stat.Mode & syscall.S_IFMT {
- case syscall.S_IFREG:
- ft = regular
- case syscall.S_IFDIR:
- ft = directory
- case syscall.S_IFLNK:
- ft = symlink
- case syscall.S_IFSOCK:
+func checkSupportedFileType(stat unix.Stat_t, permitSocket bool) error {
+ switch stat.Mode & unix.S_IFMT {
+ case unix.S_IFREG, unix.S_IFDIR, unix.S_IFLNK:
+ return nil
+
+ case unix.S_IFSOCK:
if !permitSocket {
- return unknown, syscall.EPERM
+ return unix.EPERM
}
- ft = socket
+ return nil
+
default:
- return unknown, syscall.EPERM
+ return unix.EPERM
}
- return ft, nil
}
-func newLocalFile(a *attachPoint, file *fd.FD, path string, stat syscall.Stat_t) (*localFile, error) {
- ft, err := getSupportedFileType(stat, a.conf.HostUDS)
- if err != nil {
+func newLocalFile(a *attachPoint, file *fd.FD, path string, readable bool, stat unix.Stat_t) (*localFile, error) {
+ if err := checkSupportedFileType(stat, a.conf.HostUDS); err != nil {
return nil, err
}
return &localFile{
- attachPoint: a,
- hostPath: path,
- file: file,
- mode: invalidMode,
- ft: ft,
+ attachPoint: a,
+ hostPath: path,
+ file: file,
+ mode: invalidMode,
+ fileType: stat.Mode & unix.S_IFMT,
+ qid: a.makeQID(stat),
+ controlReadable: readable,
}, nil
}
@@ -335,7 +333,7 @@ func newLocalFile(a *attachPoint, file *fd.FD, path string, stat syscall.Stat_t)
// non-blocking. If anything fails, returns nil. It's better to have a file
// without host FD, than to fail the operation.
func newFDMaybe(file *fd.FD) *fd.FD {
- dupFD, err := syscall.Dup(file.FD())
+ dupFD, err := unix.Dup(file.FD())
// Technically, the runtime may call the finalizer on file as soon as
// FD() returns.
runtime.KeepAlive(file)
@@ -345,23 +343,23 @@ func newFDMaybe(file *fd.FD) *fd.FD {
dup := fd.New(dupFD)
// fd is blocking; non-blocking is required.
- if err := syscall.SetNonblock(dup.FD(), true); err != nil {
- dup.Close()
+ if err := unix.SetNonblock(dup.FD(), true); err != nil {
+ _ = dup.Close()
return nil
}
return dup
}
-func stat(fd int) (syscall.Stat_t, error) {
- var stat syscall.Stat_t
- if err := syscall.Fstat(fd, &stat); err != nil {
- return syscall.Stat_t{}, err
+func fstat(fd int) (unix.Stat_t, error) {
+ var stat unix.Stat_t
+ if err := unix.Fstat(fd, &stat); err != nil {
+ return unix.Stat_t{}, err
}
return stat, nil
}
func fchown(fd int, uid p9.UID, gid p9.GID) error {
- return syscall.Fchownat(fd, "", int(uid), int(gid), linux.AT_EMPTY_PATH|unix.AT_SYMLINK_NOFOLLOW)
+ return unix.Fchownat(fd, "", int(uid), int(gid), linux.AT_EMPTY_PATH|unix.AT_SYMLINK_NOFOLLOW)
}
// Open implements p9.File.
@@ -369,10 +367,16 @@ func (l *localFile) Open(flags p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) {
if l.isOpen() {
panic(fmt.Sprintf("attempting to open already opened file: %q", l.hostPath))
}
+ mode := flags & p9.OpenFlagsModeMask
+ if mode == p9.WriteOnly || mode == p9.ReadWrite || flags&p9.OpenTruncate != 0 {
+ if err := l.checkROMount(); err != nil {
+ return nil, p9.QID{}, 0, err
+ }
+ }
// Check if control file can be used or if a new open must be created.
var newFile *fd.FD
- if flags == p9.ReadOnly {
+ if mode == p9.ReadOnly && l.controlReadable && flags.OSFlags()&allowedOpenFlags == 0 {
log.Debugf("Open reusing control file, flags: %v, %q", flags, l.hostPath)
newFile = l.file
} else {
@@ -381,23 +385,15 @@ func (l *localFile) Open(flags p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) {
// name_to_handle_at and open_by_handle_at aren't supported by overlay2.
log.Debugf("Open reopening file, flags: %v, %q", flags, l.hostPath)
var err error
- // Constrain open flags to the open mode and O_TRUNC.
- newFile, err = reopenProcFd(l.file, openFlags|(flags.OSFlags()&(syscall.O_ACCMODE|syscall.O_TRUNC)))
+ osFlags := flags.OSFlags() & (unix.O_ACCMODE | allowedOpenFlags)
+ newFile, err = reopenProcFd(l.file, openFlags|osFlags)
if err != nil {
return nil, p9.QID{}, 0, extractErrno(err)
}
}
- stat, err := stat(newFile.FD())
- if err != nil {
- if newFile != l.file {
- newFile.Close()
- }
- return nil, p9.QID{}, 0, extractErrno(err)
- }
-
var fd *fd.FD
- if stat.Mode&syscall.S_IFMT == syscall.S_IFREG {
+ if l.fileType == unix.S_IFREG {
// Donate FD for regular files only.
fd = newFDMaybe(newFile)
}
@@ -409,38 +405,38 @@ func (l *localFile) Open(flags p9.OpenFlags) (*fd.FD, p9.QID, uint32, error) {
}
l.file = newFile
}
- l.mode = flags & p9.OpenFlagsModeMask
- return fd, l.attachPoint.makeQID(stat), 0, nil
+ l.mode = mode
+ return fd, l.qid, 0, nil
}
// Create implements p9.File.
-func (l *localFile) Create(name string, mode p9.OpenFlags, perm p9.FileMode, uid p9.UID, gid p9.GID) (*fd.FD, p9.File, p9.QID, uint32, error) {
- conf := l.attachPoint.conf
- if conf.ROMount {
- if conf.PanicOnWrite {
- panic("attempt to write to RO mount")
- }
- return nil, nil, p9.QID{}, 0, syscall.EBADF
+func (l *localFile) Create(name string, p9Flags p9.OpenFlags, perm p9.FileMode, uid p9.UID, gid p9.GID) (*fd.FD, p9.File, p9.QID, uint32, error) {
+ if err := l.checkROMount(); err != nil {
+ return nil, nil, p9.QID{}, 0, err
}
+ // Set file creation flags, plus allowed open flags from caller.
+ osFlags := openFlags | unix.O_CREAT | unix.O_EXCL
+ osFlags |= p9Flags.OSFlags() & allowedOpenFlags
+
// 'file' may be used for other operations (e.g. Walk), so read access is
// always added to flags. Note that resulting file might have a wider mode
// than needed for each particular case.
- flags := openFlags | syscall.O_CREAT | syscall.O_EXCL
+ mode := p9Flags & p9.OpenFlagsModeMask
if mode == p9.WriteOnly {
- flags |= syscall.O_RDWR
+ osFlags |= unix.O_RDWR
} else {
- flags |= mode.OSFlags()
+ osFlags |= mode.OSFlags()
}
- child, err := fd.OpenAt(l.file, name, flags, uint32(perm.Permissions()))
+ child, err := fd.OpenAt(l.file, name, osFlags, uint32(perm.Permissions()))
if err != nil {
return nil, nil, p9.QID{}, 0, extractErrno(err)
}
cu := cleanup.Make(func() {
- child.Close()
+ _ = child.Close()
// Best effort attempt to remove the file in case of failure.
- if err := syscall.Unlinkat(l.file.FD(), name); err != nil {
+ if err := unix.Unlinkat(l.file.FD(), name, 0); err != nil {
log.Warningf("error unlinking file %q after failure: %v", path.Join(l.hostPath, name), err)
}
})
@@ -449,7 +445,7 @@ func (l *localFile) Create(name string, mode p9.OpenFlags, perm p9.FileMode, uid
if err := fchown(child.FD(), uid, gid); err != nil {
return nil, nil, p9.QID{}, 0, extractErrno(err)
}
- stat, err := stat(child.FD())
+ stat, err := fstat(child.FD())
if err != nil {
return nil, nil, p9.QID{}, 0, extractErrno(err)
}
@@ -459,23 +455,21 @@ func (l *localFile) Create(name string, mode p9.OpenFlags, perm p9.FileMode, uid
hostPath: path.Join(l.hostPath, name),
file: child,
mode: mode,
+ fileType: unix.S_IFREG,
+ qid: l.attachPoint.makeQID(stat),
}
cu.Release()
- return newFDMaybe(c.file), c, l.attachPoint.makeQID(stat), 0, nil
+ return newFDMaybe(c.file), c, c.qid, 0, nil
}
// Mkdir implements p9.File.
func (l *localFile) Mkdir(name string, perm p9.FileMode, uid p9.UID, gid p9.GID) (p9.QID, error) {
- conf := l.attachPoint.conf
- if conf.ROMount {
- if conf.PanicOnWrite {
- panic("attempt to write to RO mount")
- }
- return p9.QID{}, syscall.EBADF
+ if err := l.checkROMount(); err != nil {
+ return p9.QID{}, err
}
- if err := syscall.Mkdirat(l.file.FD(), name, uint32(perm.Permissions())); err != nil {
+ if err := unix.Mkdirat(l.file.FD(), name, uint32(perm.Permissions())); err != nil {
return p9.QID{}, extractErrno(err)
}
cu := cleanup.Make(func() {
@@ -487,7 +481,7 @@ func (l *localFile) Mkdir(name string, perm p9.FileMode, uid p9.UID, gid p9.GID)
defer cu.Clean()
// Open directory to change ownership and stat it.
- flags := syscall.O_DIRECTORY | syscall.O_RDONLY | openFlags
+ flags := unix.O_DIRECTORY | unix.O_RDONLY | openFlags
f, err := fd.OpenAt(l.file, name, flags, 0)
if err != nil {
return p9.QID{}, extractErrno(err)
@@ -497,7 +491,7 @@ func (l *localFile) Mkdir(name string, perm p9.FileMode, uid p9.UID, gid p9.GID)
if err := fchown(f.FD(), uid, gid); err != nil {
return p9.QID{}, extractErrno(err)
}
- stat, err := stat(f.FD())
+ stat, err := fstat(f.FD())
if err != nil {
return p9.QID{}, extractErrno(err)
}
@@ -508,61 +502,80 @@ func (l *localFile) Mkdir(name string, perm p9.FileMode, uid p9.UID, gid p9.GID)
// Walk implements p9.File.
func (l *localFile) Walk(names []string) ([]p9.QID, p9.File, error) {
+ qids, file, _, err := l.walk(names)
+ return qids, file, err
+}
+
+// WalkGetAttr implements p9.File.
+func (l *localFile) WalkGetAttr(names []string) ([]p9.QID, p9.File, p9.AttrMask, p9.Attr, error) {
+ qids, file, stat, err := l.walk(names)
+ if err != nil {
+ return nil, nil, p9.AttrMask{}, p9.Attr{}, err
+ }
+ mask, attr := l.fillAttr(stat)
+ return qids, file, mask, attr, nil
+}
+
+func (l *localFile) walk(names []string) ([]p9.QID, p9.File, unix.Stat_t, error) {
// Duplicate current file if 'names' is empty.
if len(names) == 0 {
- newFile, err := openAnyFile(l.hostPath, func(mode int) (*fd.FD, error) {
+ newFile, readable, err := openAnyFile(l.hostPath, func(mode int) (*fd.FD, error) {
return reopenProcFd(l.file, openFlags|mode)
})
if err != nil {
- return nil, nil, extractErrno(err)
+ return nil, nil, unix.Stat_t{}, extractErrno(err)
}
- stat, err := stat(newFile.FD())
+ stat, err := fstat(newFile.FD())
if err != nil {
- newFile.Close()
- return nil, nil, extractErrno(err)
+ _ = newFile.Close()
+ return nil, nil, unix.Stat_t{}, extractErrno(err)
}
c := &localFile{
- attachPoint: l.attachPoint,
- hostPath: l.hostPath,
- file: newFile,
- mode: invalidMode,
+ attachPoint: l.attachPoint,
+ hostPath: l.hostPath,
+ file: newFile,
+ mode: invalidMode,
+ fileType: l.fileType,
+ qid: l.attachPoint.makeQID(stat),
+ controlReadable: readable,
}
- return []p9.QID{l.attachPoint.makeQID(stat)}, c, nil
+ return []p9.QID{c.qid}, c, stat, nil
}
var qids []p9.QID
+ var lastStat unix.Stat_t
last := l
for _, name := range names {
- f, path, err := openAnyFileFromParent(last, name)
+ f, path, readable, err := openAnyFileFromParent(last, name)
if last != l {
- last.Close()
+ _ = last.Close()
}
if err != nil {
- return nil, nil, extractErrno(err)
+ return nil, nil, unix.Stat_t{}, extractErrno(err)
}
- stat, err := stat(f.FD())
+ lastStat, err = fstat(f.FD())
if err != nil {
- f.Close()
- return nil, nil, extractErrno(err)
+ _ = f.Close()
+ return nil, nil, unix.Stat_t{}, extractErrno(err)
}
- c, err := newLocalFile(last.attachPoint, f, path, stat)
+ c, err := newLocalFile(last.attachPoint, f, path, readable, lastStat)
if err != nil {
- f.Close()
- return nil, nil, extractErrno(err)
+ _ = f.Close()
+ return nil, nil, unix.Stat_t{}, extractErrno(err)
}
- qids = append(qids, l.attachPoint.makeQID(stat))
+ qids = append(qids, c.qid)
last = c
}
- return qids, last, nil
+ return qids, last, lastStat, nil
}
// StatFS implements p9.File.
func (l *localFile) StatFS() (p9.FSStat, error) {
- var s syscall.Statfs_t
- if err := syscall.Fstatfs(l.file.FD(), &s); err != nil {
+ var s unix.Statfs_t
+ if err := unix.Fstatfs(l.file.FD(), &s); err != nil {
return p9.FSStat{}, extractErrno(err)
}
@@ -582,9 +595,9 @@ func (l *localFile) StatFS() (p9.FSStat, error) {
// FSync implements p9.File.
func (l *localFile) FSync() error {
if !l.isOpen() {
- return syscall.EBADF
+ return unix.EBADF
}
- if err := syscall.Fsync(l.file.FD()); err != nil {
+ if err := unix.Fsync(l.file.FD()); err != nil {
return extractErrno(err)
}
return nil
@@ -592,11 +605,15 @@ func (l *localFile) FSync() error {
// GetAttr implements p9.File.
func (l *localFile) GetAttr(_ p9.AttrMask) (p9.QID, p9.AttrMask, p9.Attr, error) {
- stat, err := stat(l.file.FD())
+ stat, err := fstat(l.file.FD())
if err != nil {
return p9.QID{}, p9.AttrMask{}, p9.Attr{}, extractErrno(err)
}
+ mask, attr := l.fillAttr(stat)
+ return l.qid, mask, attr, nil
+}
+func (l *localFile) fillAttr(stat unix.Stat_t) (p9.AttrMask, p9.Attr) {
attr := p9.Attr{
Mode: p9.FileMode(stat.Mode),
UID: p9.UID(stat.Uid),
@@ -625,20 +642,15 @@ func (l *localFile) GetAttr(_ p9.AttrMask) (p9.QID, p9.AttrMask, p9.Attr, error)
MTime: true,
CTime: true,
}
-
- return l.attachPoint.makeQID(stat), valid, attr, nil
+ return valid, attr
}
// SetAttr implements p9.File. Due to mismatch in file API, options
// cannot be changed atomically and user may see partial changes when
// an error happens.
func (l *localFile) SetAttr(valid p9.SetAttrMask, attr p9.SetAttr) error {
- conf := l.attachPoint.conf
- if conf.ROMount {
- if conf.PanicOnWrite {
- panic("attempt to write to RO mount")
- }
- return syscall.EBADF
+ if err := l.checkROMount(); err != nil {
+ return err
}
allowed := p9.SetAttrMask{
@@ -661,13 +673,13 @@ func (l *localFile) SetAttr(valid p9.SetAttrMask, attr p9.SetAttr) error {
// consistent result that is not attribute dependent.
if !valid.IsSubsetOf(allowed) {
log.Warningf("SetAttr() failed for %q, mask: %v", l.hostPath, valid)
- return syscall.EPERM
+ return unix.EPERM
}
// Check if it's possible to use cached file, or if another one needs to be
// opened for write.
f := l.file
- if l.ft == regular && l.mode != p9.WriteOnly && l.mode != p9.ReadWrite {
+ if l.fileType == unix.S_IFREG && l.mode != p9.WriteOnly && l.mode != p9.ReadWrite {
var err error
f, err = reopenProcFd(l.file, openFlags|os.O_WRONLY)
if err != nil {
@@ -688,21 +700,21 @@ func (l *localFile) SetAttr(valid p9.SetAttrMask, attr p9.SetAttr) error {
// over another.
var err error
if valid.Permissions {
- if cerr := syscall.Fchmod(f.FD(), uint32(attr.Permissions)); cerr != nil {
+ if cerr := unix.Fchmod(f.FD(), uint32(attr.Permissions)); cerr != nil {
log.Debugf("SetAttr fchmod failed %q, err: %v", l.hostPath, cerr)
err = extractErrno(cerr)
}
}
if valid.Size {
- if terr := syscall.Ftruncate(f.FD(), int64(attr.Size)); terr != nil {
+ if terr := unix.Ftruncate(f.FD(), int64(attr.Size)); terr != nil {
log.Debugf("SetAttr ftruncate failed %q, err: %v", l.hostPath, terr)
err = extractErrno(terr)
}
}
if valid.ATime || valid.MTime {
- utimes := [2]syscall.Timespec{
+ utimes := [2]unix.Timespec{
{Sec: 0, Nsec: linux.UTIME_OMIT},
{Sec: 0, Nsec: linux.UTIME_OMIT},
}
@@ -723,15 +735,15 @@ func (l *localFile) SetAttr(valid p9.SetAttrMask, attr p9.SetAttr) error {
}
}
- if l.ft == symlink {
+ if l.fileType == unix.S_IFLNK {
// utimensat operates different that other syscalls. To operate on a
// symlink it *requires* AT_SYMLINK_NOFOLLOW with dirFD and a non-empty
// name.
- parent, err := syscall.Open(path.Dir(l.hostPath), openFlags|unix.O_PATH, 0)
+ parent, err := unix.Open(path.Dir(l.hostPath), openFlags|unix.O_PATH, 0)
if err != nil {
return extractErrno(err)
}
- defer syscall.Close(parent)
+ defer unix.Close(parent)
if terr := utimensat(parent, path.Base(l.hostPath), utimes, linux.AT_SYMLINK_NOFOLLOW); terr != nil {
log.Debugf("SetAttr utimens failed %q, err: %v", l.hostPath, terr)
@@ -756,7 +768,7 @@ func (l *localFile) SetAttr(valid p9.SetAttrMask, attr p9.SetAttr) error {
if valid.GID {
gid = int(attr.GID)
}
- if oerr := syscall.Fchownat(f.FD(), "", uid, gid, linux.AT_EMPTY_PATH|linux.AT_SYMLINK_NOFOLLOW); oerr != nil {
+ if oerr := unix.Fchownat(f.FD(), "", uid, gid, linux.AT_EMPTY_PATH|linux.AT_SYMLINK_NOFOLLOW); oerr != nil {
log.Debugf("SetAttr fchownat failed %q, err: %v", l.hostPath, oerr)
err = extractErrno(oerr)
}
@@ -766,28 +778,28 @@ func (l *localFile) SetAttr(valid p9.SetAttrMask, attr p9.SetAttr) error {
}
func (*localFile) GetXattr(string, uint64) (string, error) {
- return "", syscall.EOPNOTSUPP
+ return "", unix.EOPNOTSUPP
}
func (*localFile) SetXattr(string, string, uint32) error {
- return syscall.EOPNOTSUPP
+ return unix.EOPNOTSUPP
}
func (*localFile) ListXattr(uint64) (map[string]struct{}, error) {
- return nil, syscall.EOPNOTSUPP
+ return nil, unix.EOPNOTSUPP
}
func (*localFile) RemoveXattr(string) error {
- return syscall.EOPNOTSUPP
+ return unix.EOPNOTSUPP
}
// Allocate implements p9.File.
func (l *localFile) Allocate(mode p9.AllocateMode, offset, length uint64) error {
if !l.isOpen() {
- return syscall.EBADF
+ return unix.EBADF
}
- if err := syscall.Fallocate(l.file.FD(), mode.ToLinux(), int64(offset), int64(length)); err != nil {
+ if err := unix.Fallocate(l.file.FD(), mode.ToLinux(), int64(offset), int64(length)); err != nil {
return extractErrno(err)
}
return nil
@@ -800,12 +812,8 @@ func (*localFile) Rename(p9.File, string) error {
// RenameAt implements p9.File.RenameAt.
func (l *localFile) RenameAt(oldName string, directory p9.File, newName string) error {
- conf := l.attachPoint.conf
- if conf.ROMount {
- if conf.PanicOnWrite {
- panic("attempt to write to RO mount")
- }
- return syscall.EBADF
+ if err := l.checkROMount(); err != nil {
+ return err
}
newParent := directory.(*localFile)
@@ -818,10 +826,10 @@ func (l *localFile) RenameAt(oldName string, directory p9.File, newName string)
// ReadAt implements p9.File.
func (l *localFile) ReadAt(p []byte, offset uint64) (int, error) {
if l.mode != p9.ReadOnly && l.mode != p9.ReadWrite {
- return 0, syscall.EBADF
+ return 0, unix.EBADF
}
if !l.isOpen() {
- return 0, syscall.EBADF
+ return 0, unix.EBADF
}
r, err := l.file.ReadAt(p, int64(offset))
@@ -836,10 +844,10 @@ func (l *localFile) ReadAt(p []byte, offset uint64) (int, error) {
// WriteAt implements p9.File.
func (l *localFile) WriteAt(p []byte, offset uint64) (int, error) {
if l.mode != p9.WriteOnly && l.mode != p9.ReadWrite {
- return 0, syscall.EBADF
+ return 0, unix.EBADF
}
if !l.isOpen() {
- return 0, syscall.EBADF
+ return 0, unix.EBADF
}
w, err := l.file.WriteAt(p, int64(offset))
@@ -851,12 +859,8 @@ func (l *localFile) WriteAt(p []byte, offset uint64) (int, error) {
// Symlink implements p9.File.
func (l *localFile) Symlink(target, newName string, uid p9.UID, gid p9.GID) (p9.QID, error) {
- conf := l.attachPoint.conf
- if conf.ROMount {
- if conf.PanicOnWrite {
- panic("attempt to write to RO mount")
- }
- return p9.QID{}, syscall.EBADF
+ if err := l.checkROMount(); err != nil {
+ return p9.QID{}, err
}
if err := unix.Symlinkat(target, l.file.FD(), newName); err != nil {
@@ -864,7 +868,7 @@ func (l *localFile) Symlink(target, newName string, uid p9.UID, gid p9.GID) (p9.
}
cu := cleanup.Make(func() {
// Best effort attempt to remove the symlink in case of failure.
- if err := syscall.Unlinkat(l.file.FD(), newName); err != nil {
+ if err := unix.Unlinkat(l.file.FD(), newName, 0); err != nil {
log.Warningf("error unlinking file %q after failure: %v", path.Join(l.hostPath, newName), err)
}
})
@@ -880,7 +884,7 @@ func (l *localFile) Symlink(target, newName string, uid p9.UID, gid p9.GID) (p9.
if err := fchown(f.FD(), uid, gid); err != nil {
return p9.QID{}, extractErrno(err)
}
- stat, err := stat(f.FD())
+ stat, err := fstat(f.FD())
if err != nil {
return p9.QID{}, extractErrno(err)
}
@@ -891,12 +895,8 @@ func (l *localFile) Symlink(target, newName string, uid p9.UID, gid p9.GID) (p9.
// Link implements p9.File.
func (l *localFile) Link(target p9.File, newName string) error {
- conf := l.attachPoint.conf
- if conf.ROMount {
- if conf.PanicOnWrite {
- panic("attempt to write to RO mount")
- }
- return syscall.EBADF
+ if err := l.checkROMount(); err != nil {
+ return err
}
targetFile := target.(*localFile)
@@ -907,23 +907,53 @@ func (l *localFile) Link(target p9.File, newName string) error {
}
// Mknod implements p9.File.
-//
-// Not implemented.
-func (*localFile) Mknod(_ string, _ p9.FileMode, _ uint32, _ uint32, _ p9.UID, _ p9.GID) (p9.QID, error) {
+func (l *localFile) Mknod(name string, mode p9.FileMode, _ uint32, _ uint32, uid p9.UID, gid p9.GID) (p9.QID, error) {
+ if err := l.checkROMount(); err != nil {
+ return p9.QID{}, err
+ }
+
// From mknod(2) man page:
// "EPERM: [...] if the filesystem containing pathname does not support
// the type of node requested."
- return p9.QID{}, syscall.EPERM
+ if mode.FileType() != p9.ModeRegular {
+ return p9.QID{}, unix.EPERM
+ }
+
+ // Allow Mknod to create regular files.
+ if err := unix.Mknodat(l.file.FD(), name, uint32(mode), 0); err != nil {
+ return p9.QID{}, err
+ }
+ cu := cleanup.Make(func() {
+ // Best effort attempt to remove the file in case of failure.
+ if err := unix.Unlinkat(l.file.FD(), name, 0); err != nil {
+ log.Warningf("error unlinking file %q after failure: %v", path.Join(l.hostPath, name), err)
+ }
+ })
+ defer cu.Clean()
+
+ // Open file to change ownership and stat it.
+ child, err := fd.OpenAt(l.file, name, unix.O_PATH|openFlags, 0)
+ if err != nil {
+ return p9.QID{}, extractErrno(err)
+ }
+ defer child.Close()
+
+ if err := fchown(child.FD(), uid, gid); err != nil {
+ return p9.QID{}, extractErrno(err)
+ }
+ stat, err := fstat(child.FD())
+ if err != nil {
+ return p9.QID{}, extractErrno(err)
+ }
+
+ cu.Release()
+ return l.attachPoint.makeQID(stat), nil
}
// UnlinkAt implements p9.File.
func (l *localFile) UnlinkAt(name string, flags uint32) error {
- conf := l.attachPoint.conf
- if conf.ROMount {
- if conf.PanicOnWrite {
- panic("attempt to write to RO mount")
- }
- return syscall.EBADF
+ if err := l.checkROMount(); err != nil {
+ return err
}
if err := unix.Unlinkat(l.file.FD(), name, int(flags)); err != nil {
@@ -935,10 +965,10 @@ func (l *localFile) UnlinkAt(name string, flags uint32) error {
// Readdir implements p9.File.
func (l *localFile) Readdir(offset uint64, count uint32) ([]p9.Dirent, error) {
if l.mode != p9.ReadOnly && l.mode != p9.ReadWrite {
- return nil, syscall.EBADF
+ return nil, unix.EBADF
}
if !l.isOpen() {
- return nil, syscall.EBADF
+ return nil, unix.EBADF
}
// Readdirnames is a cursor over directories, so seek back to 0 to ensure it's
@@ -949,10 +979,13 @@ func (l *localFile) Readdir(offset uint64, count uint32) ([]p9.Dirent, error) {
skip := uint64(0)
- // Check if the file is at the correct position already. If not, seek to the
- // beginning and read the entire directory again.
- if l.lastDirentOffset != offset {
- if _, err := syscall.Seek(l.file.FD(), 0, 0); err != nil {
+ // Check if the file is at the correct position already. If not, seek to
+ // the beginning and read the entire directory again. We always seek if
+ // offset is 0, since this is side-effectual (equivalent to rewinddir(3),
+ // which causes the directory stream to resynchronize with the directory's
+ // current contents).
+ if l.lastDirentOffset != offset || offset == 0 {
+ if _, err := unix.Seek(l.file.FD(), 0, 0); err != nil {
return nil, extractErrno(err)
}
skip = offset
@@ -985,7 +1018,7 @@ func (l *localFile) readDirent(f int, offset uint64, count uint32, skip uint64)
end := offset + uint64(count)
for offset < end {
- dirSize, err := syscall.ReadDirent(f, direntsBuf)
+ dirSize, err := unix.ReadDirent(f, direntsBuf)
if err != nil {
return dirents, err
}
@@ -994,7 +1027,7 @@ func (l *localFile) readDirent(f int, offset uint64, count uint32, skip uint64)
}
names := names[:0]
- _, _, names = syscall.ParseDirent(direntsBuf[:dirSize], -1, names)
+ _, _, names = unix.ParseDirent(direntsBuf[:dirSize], -1, names)
// Skip over entries that the caller is not interested in.
if skip > 0 {
@@ -1039,7 +1072,7 @@ func (l *localFile) Readlink() (string, error) {
return string(b[:n]), nil
}
}
- return "", syscall.ENOMEM
+ return "", unix.ENOMEM
}
// Flush implements p9.File.
@@ -1050,7 +1083,7 @@ func (l *localFile) Flush() error {
// Connect implements p9.File.
func (l *localFile) Connect(flags p9.ConnectFlags) (*fd.FD, error) {
if !l.attachPoint.conf.HostUDS {
- return nil, syscall.ECONNREFUSED
+ return nil, unix.ECONNREFUSED
}
// TODO(gvisor.dev/issue/1003): Due to different app vs replacement
@@ -1058,34 +1091,34 @@ func (l *localFile) Connect(flags p9.ConnectFlags) (*fd.FD, error) {
// fit f.path in our sockaddr. We'd need to redirect through a shorter
// path in order to actually connect to this socket.
if len(l.hostPath) > linux.UnixPathMax {
- return nil, syscall.ECONNREFUSED
+ return nil, unix.ECONNREFUSED
}
var stype int
switch flags {
case p9.StreamSocket:
- stype = syscall.SOCK_STREAM
+ stype = unix.SOCK_STREAM
case p9.DgramSocket:
- stype = syscall.SOCK_DGRAM
+ stype = unix.SOCK_DGRAM
case p9.SeqpacketSocket:
- stype = syscall.SOCK_SEQPACKET
+ stype = unix.SOCK_SEQPACKET
default:
- return nil, syscall.ENXIO
+ return nil, unix.ENXIO
}
- f, err := syscall.Socket(syscall.AF_UNIX, stype, 0)
+ f, err := unix.Socket(unix.AF_UNIX, stype, 0)
if err != nil {
return nil, err
}
- if err := syscall.SetNonblock(f, true); err != nil {
- syscall.Close(f)
+ if err := unix.SetNonblock(f, true); err != nil {
+ _ = unix.Close(f)
return nil, err
}
- sa := syscall.SockaddrUnix{Name: l.hostPath}
- if err := syscall.Connect(f, &sa); err != nil {
- syscall.Close(f)
+ sa := unix.SockaddrUnix{Name: l.hostPath}
+ if err := unix.Connect(f, &sa); err != nil {
+ _ = unix.Close(f)
return nil, err
}
@@ -1110,7 +1143,7 @@ func (l *localFile) Renamed(newDir p9.File, newName string) {
}
// extractErrno tries to determine the errno.
-func extractErrno(err error) syscall.Errno {
+func extractErrno(err error) unix.Errno {
if err == nil {
// This should never happen. The likely result will be that
// some user gets the frustrating "error: SUCCESS" message.
@@ -1120,18 +1153,18 @@ func extractErrno(err error) syscall.Errno {
switch err {
case os.ErrNotExist:
- return syscall.ENOENT
+ return unix.ENOENT
case os.ErrExist:
- return syscall.EEXIST
+ return unix.EEXIST
case os.ErrPermission:
- return syscall.EACCES
+ return unix.EACCES
case os.ErrInvalid:
- return syscall.EINVAL
+ return unix.EINVAL
}
// See if it's an errno or a common wrapped error.
switch e := err.(type) {
- case syscall.Errno:
+ case unix.Errno:
return e
case *os.PathError:
return extractErrno(e.Err)
@@ -1143,5 +1176,12 @@ func extractErrno(err error) syscall.Errno {
// Fall back to EIO.
log.Debugf("Unknown error: %v, defaulting to EIO", err)
- return syscall.EIO
+ return unix.EIO
+}
+
+func (l *localFile) checkROMount() error {
+ if conf := l.attachPoint.conf; conf.ROMount {
+ return unix.EROFS
+ }
+ return nil
}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-23 09:30:06 +0000