fuse

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 Go to latest Published: Jun 11, 2024 License: BSD-2-Clause, BSD-3-Clause, HPND Imports: 16 Imported by: 0

README

bazil.org/fuse -- Filesystems in Go

bazil.org/fuse is a Go library for writing FUSE userspace filesystems.

It is a from-scratch implementation of the kernel-userspace communication protocol, and does not use the C library from the project called FUSE. bazil.org/fuse embraces Go fully for safety and ease of programming.

Here’s how to get going:

go get bazil.org/fuse

Website: http://bazil.org/fuse/

Github repository: https://github.com/bazil/fuse

API docs: http://godoc.org/bazil.org/fuse

Our thanks to Russ Cox for his fuse library, which this project is based on.

Documentation

Overview

Package fuse enables writing FUSE file systems on Linux, OS X, and FreeBSD.

On OS X, it requires OSXFUSE (http://osxfuse.github.com/).

There are two approaches to writing a FUSE file system. The first is to speak the low-level message protocol, reading from a Conn using ReadRequest and writing using the various Respond methods. This approach is closest to the actual interaction with the kernel and can be the simplest one in contexts such as protocol translators.

Servers of synthesized file systems tend to share common bookkeeping abstracted away by the second approach, which is to call fs.Serve to serve the FUSE protocol using an implementation of the service methods in the interfaces FS* (file system), Node* (file or directory), and Handle* (opened file or directory). There are a daunting number of such methods that can be written, but few are required. The specific methods are described in the documentation for those interfaces.

The hellofs subdirectory contains a simple illustration of the fs.Serve approach.

Service Methods

The required and optional methods for the FS, Node, and Handle interfaces have the general form 

Op(ctx context.Context, req *OpRequest, resp *OpResponse) error

where Op is the name of a FUSE operation. Op reads request parameters from req and writes results to resp. An operation whose only result is the error result omits the resp parameter.

Multiple goroutines may call service methods simultaneously; the methods being called are responsible for appropriate synchronization.

The operation must not hold on to the request or response, including any []byte fields such as WriteRequest.Data or SetxattrRequest.Xattr.

Errors

Operations can return errors. The FUSE interface can only communicate POSIX errno error numbers to file system clients, the message is not visible to file system clients. The returned error can implement ErrorNumber to control the errno returned. Without ErrorNumber, a generic errno (EIO) is returned.

Error messages will be visible in the debug log as part of the response.

Interrupted Operations

In some file systems, some operations may take an undetermined amount of time. For example, a Read waiting for a network message or a matching Write might wait indefinitely. If the request is cancelled and no longer needed, the context will be cancelled. Blocking operations should select on a receive from ctx.Done() and attempt to abort the operation early if the receive succeeds (meaning the channel is closed). To indicate that the operation failed because it was aborted, return fuse.EINTR.

If an operation does not block for an indefinite amount of time, supporting cancellation is not necessary.

Authentication

All requests types embed a Header, meaning that the method can inspect req.Pid, req.Uid, and req.Gid as necessary to implement permission checking. The kernel FUSE layer normally prevents other users from accessing the FUSE file system (to change this, see AllowOther, AllowRoot), but does not enforce access modes (to change this, see DefaultPermissions).

Mount Options

Behavior and metadata of the mounted file system can be changed by passing MountOption values to Mount.

Index

Constants

View Source 
const (
	// ENOSYS indicates that the call is not supported.
	ENOSYS = Errno(syscall.ENOSYS)

	// ESTALE is used by Serve to respond to violations of the FUSE protocol.
	ESTALE = Errno(syscall.ESTALE)

	ENOENT = Errno(syscall.ENOENT)
	EIO    = Errno(syscall.EIO)
	EPERM  = Errno(syscall.EPERM)

	// EINTR indicates request was interrupted by an InterruptRequest.
	// See also fs.Intr.
	EINTR = Errno(syscall.EINTR)

	ERANGE  = Errno(syscall.ERANGE)
	ENOTSUP = Errno(syscall.ENOTSUP)
	EEXIST  = Errno(syscall.EEXIST)
)
View Source 
const DefaultErrno = EIO

DefaultErrno is the errno used when error returned does not implement ErrorNumber.

View Source 
const (
	ENODATA = Errno(syscall.ENODATA)
)
View Source 
const ErrNoXattr = errNoXattr

ErrNoXattr is a platform-independent error value meaning the extended attribute was not found. It can be used to respond to GetxattrRequest and such.

Variables

View Source 
var (
	OSXFUSELocationV3 = OSXFUSEPaths{
		DevicePrefix: "/dev/osxfuse",
		Load:         "/Library/Filesystems/osxfuse.fs/Contents/Resources/load_osxfuse",
		Mount:        "/Library/Filesystems/osxfuse.fs/Contents/Resources/mount_osxfuse",
		DaemonVar:    "MOUNT_OSXFUSE_DAEMON_PATH",
	}
	OSXFUSELocationV2 = OSXFUSEPaths{
		DevicePrefix: "/dev/osxfuse",
		Load:         "/Library/Filesystems/osxfusefs.fs/Support/load_osxfusefs",
		Mount:        "/Library/Filesystems/osxfusefs.fs/Support/mount_osxfusefs",
		DaemonVar:    "MOUNT_FUSEFS_DAEMON_PATH",
	}
)

Default paths for OSXFUSE. See OSXFUSELocations.

View Source 
var Debug func(msg interface{}) = nop

Debug is called to output debug messages, including protocol traces. The default behavior is to do nothing.

The messages have human-friendly string representations and are safe to marshal to JSON.

Implementations must not retain msg.

View Source 
var ErrCannotCombineAllowOtherAndAllowRoot = errors.New("cannot combine AllowOther and AllowRoot")
View Source 
var (
	ErrClosedWithoutInit = errors.New("fuse connection closed without init")
)
View Source 
var (
	ErrNotCached = notCachedError{}
)
View Source 
var (
	// ErrOSXFUSENotFound is returned from Mount when the OSXFUSE
	// installation is not detected.
	//
	// Only happens on OS X. Make sure OSXFUSE is installed, or see
	// OSXFUSELocations for customization.
	ErrOSXFUSENotFound = errors.New("cannot locate OSXFUSE")
)

Functions

func AppendDirent 

func AppendDirent(data []byte, dir Dirent) []byte

AppendDirent appends the encoded form of a directory entry to data and returns the resulting slice.

func Unmount 

func Unmount(dir string) error

Unmount tries to unmount the filesystem mounted at dir.

Types

type AccessRequest 

type AccessRequest struct {
	Header `json:"-"`
	Mask   uint32
}

An AccessRequest asks whether the file can be accessed for the purpose specified by the mask.

func (*AccessRequest) Respond 

func (r *AccessRequest) Respond()

Respond replies to the request indicating that access is allowed. To deny access, use RespondError.

func (*AccessRequest) String 

func (r *AccessRequest) String() string

type Attr 

type Attr struct {
	Valid time.Duration // how long Attr can be cached

	Inode     uint64      // inode number
	Size      uint64      // size in bytes
	Blocks    uint64      // size in 512-byte units
	Atime     time.Time   // time of last access
	Mtime     time.Time   // time of last modification
	Ctime     time.Time   // time of last inode change
	Crtime    time.Time   // time of creation (OS X only)
	Mode      os.FileMode // file mode
	Nlink     uint32      // number of links (usually 1)
	Uid       uint32      // owner uid
	Gid       uint32      // group gid
	Rdev      uint32      // device numbers
	Flags     uint32      // chflags(2) flags (OS X only)
	BlockSize uint32      // preferred blocksize for filesystem I/O
}

An Attr is the metadata for a single file or directory.

func (Attr) String 

func (a Attr) String() string

type Conn 

type Conn struct {
	// Ready is closed when the mount is complete or has failed.
	Ready <-chan struct{}

	// MountError stores any error from the mount process. Only valid
	// after Ready is closed.
	MountError error
	// contains filtered or unexported fields
}

A Conn represents a connection to a mounted FUSE file system.

func Mount 

func Mount(dir string, options ...MountOption) (*Conn, error)

Mount mounts a new FUSE connection on the named directory and returns a connection for reading and writing FUSE messages.

After a successful return, caller must call Close to free resources.

Even on successful return, the new mount is not guaranteed to be visible until after Conn.Ready is closed. See Conn.MountError for possible errors. Incoming requests on Conn must be served to make progress.

func (*Conn) Close 

func (c *Conn) Close() error

Close closes the FUSE connection.

func (*Conn) InvalidateEntry 

func (c *Conn) InvalidateEntry(parent NodeID, name string) error

InvalidateEntry invalidates the kernel cache of the directory entry identified by parent directory node ID and entry basename.

Kernel may or may not cache directory listings. To invalidate those, use InvalidateNode to invalidate all of the data for a directory. (As of 2015-06, Linux FUSE does not cache directory listings.)

Returns ErrNotCached if the kernel is not currently caching the node.

func (*Conn) InvalidateNode 

func (c *Conn) InvalidateNode(nodeID NodeID, off int64, size int64) error

InvalidateNode invalidates the kernel cache of the attributes and a range of the data of a node.

Giving offset 0 and size -1 means all data. To invalidate just the attributes, give offset 0 and size 0.

Returns ErrNotCached if the kernel is not currently caching the node.

func (*Conn) Protocol 

func (c *Conn) Protocol() Protocol

func (*Conn) ReadRequest 

func (c *Conn) ReadRequest() (Request, error)

ReadRequest returns the next FUSE request from the kernel.

Caller must call either Request.Respond or Request.RespondError in a reasonable time. Caller must not retain Request after that call.

type CreateRequest 

type CreateRequest struct {
	Header `json:"-"`
	Name   string
	Flags  OpenFlags
	Mode   os.FileMode
	// Umask of the request. Not supported on OS X.
	Umask os.FileMode
}

A CreateRequest asks to create and open a file (not a directory).

func (*CreateRequest) Respond 

func (r *CreateRequest) Respond(resp *CreateResponse)

Respond replies to the request with the given response.

func (*CreateRequest) String 

func (r *CreateRequest) String() string

type CreateResponse 

type CreateResponse struct {
	LookupResponse
	OpenResponse
}

A CreateResponse is the response to a CreateRequest. It describes the created node and opened handle.

func (*CreateResponse) String 

func (r *CreateResponse) String() string

type DestroyRequest 

type DestroyRequest struct {
	Header `json:"-"`
}

A DestroyRequest is sent by the kernel when unmounting the file system. No more requests will be received after this one, but it should still be responded to.

func (*DestroyRequest) Respond 

func (r *DestroyRequest) Respond()

Respond replies to the request.

func (*DestroyRequest) String 

func (r *DestroyRequest) String() string

type Dirent 

type Dirent struct {
	// Inode this entry names.
	Inode uint64

	// Type of the entry, for example DT_File.
	//
	// Setting this is optional. The zero value (DT_Unknown) means
	// callers will just need to do a Getattr when the type is
	// needed. Providing a type can speed up operations
	// significantly.
	Type DirentType

	// Name of the entry
	Name string
}

A Dirent represents a single directory entry.

type DirentType 

type DirentType uint32

Type of an entry in a directory listing. 

const (
	DT_Unknown DirentType = 0
	DT_Socket  DirentType = syscall.S_IFSOCK >> 12
	DT_Link    DirentType = syscall.S_IFLNK >> 12
	DT_File    DirentType = syscall.S_IFREG >> 12
	DT_Block   DirentType = syscall.S_IFBLK >> 12
	DT_Dir     DirentType = syscall.S_IFDIR >> 12
	DT_Char    DirentType = syscall.S_IFCHR >> 12
	DT_FIFO    DirentType = syscall.S_IFIFO >> 12
)

func (DirentType) String 

func (t DirentType) String() string

type Errno 

type Errno syscall.Errno

Errno implements Error and ErrorNumber using a syscall.Errno.

func (Errno) Errno 

func (e Errno) Errno() Errno

func (Errno) ErrnoName 

func (e Errno) ErrnoName() string

ErrnoName returns the short non-numeric identifier for this errno. For example, "EIO".

func (Errno) Error 

func (e Errno) Error() string

func (Errno) MarshalText 

func (e Errno) MarshalText() ([]byte, error)

func (Errno) String 

func (e Errno) String() string

type ErrorNumber 

type ErrorNumber interface {
	// Errno returns the the error number (errno) for this error.
	Errno() Errno
}

An ErrorNumber is an error with a specific error number.

Operations may return an error value that implements ErrorNumber to control what specific error number (errno) to return.

type ExchangeDataRequest 

type ExchangeDataRequest struct {
	Header           `json:"-"`
	OldDir, NewDir   NodeID
	OldName, NewName string
}

An ExchangeDataRequest is a request to exchange the contents of two files, while leaving most metadata untouched.

This request comes from OS X exchangedata(2) and represents its specific semantics. Crucially, it is very different from Linux renameat(2) RENAME_EXCHANGE.

https://developer.apple.com/library/mac/documentation/Darwin/Reference/ManPages/man2/exchangedata.2.html

func (*ExchangeDataRequest) Respond 

func (r *ExchangeDataRequest) Respond()

func (*ExchangeDataRequest) String 

func (r *ExchangeDataRequest) String() string

type FlushRequest 

type FlushRequest struct {
	Header    `json:"-"`
	Handle    HandleID
	Flags     uint32
	LockOwner uint64
}

A FlushRequest asks for the current state of an open file to be flushed to storage, as when a file descriptor is being closed. A single opened Handle may receive multiple FlushRequests over its lifetime.

func (*FlushRequest) Respond 

func (r *FlushRequest) Respond()

Respond replies to the request, indicating that the flush succeeded.

func (*FlushRequest) String 

func (r *FlushRequest) String() string

type ForgetRequest 

type ForgetRequest struct {
	Header `json:"-"`
	N      uint64
}

A ForgetRequest is sent by the kernel when forgetting about r.Node as returned by r.N lookup requests.

func (*ForgetRequest) Respond 

func (r *ForgetRequest) Respond()

Respond replies to the request, indicating that the forgetfulness has been recorded.

func (*ForgetRequest) String 

func (r *ForgetRequest) String() string

type FsyncRequest 

type FsyncRequest struct {
	Header `json:"-"`
	Handle HandleID
	// TODO bit 1 is datasync, not well documented upstream
	Flags uint32
	Dir   bool
}

func (*FsyncRequest) Respond 

func (r *FsyncRequest) Respond()

func (*FsyncRequest) String 

func (r *FsyncRequest) String() string

type GetattrFlags 

type GetattrFlags uint32

GetattrFlags are bit flags that can be seen in GetattrRequest. 

const (
	// Indicates the handle is valid.
	GetattrFh GetattrFlags = 1 << 0
)

func (GetattrFlags) String 

func (fl GetattrFlags) String() string

type GetattrRequest 

type GetattrRequest struct {
	Header `json:"-"`
	Flags  GetattrFlags
	Handle HandleID
}

A GetattrRequest asks for the metadata for the file denoted by r.Node.

func (*GetattrRequest) Respond 

func (r *GetattrRequest) Respond(resp *GetattrResponse)

Respond replies to the request with the given response.

func (*GetattrRequest) String 

func (r *GetattrRequest) String() string

type GetattrResponse 

type GetattrResponse struct {
	Attr Attr // file attributes
}

A GetattrResponse is the response to a GetattrRequest.

func (*GetattrResponse) String 

func (r *GetattrResponse) String() string

type GetxattrRequest 

type GetxattrRequest struct {
	Header `json:"-"`

	// Maximum size to return.
	Size uint32

	// Name of the attribute requested.
	Name string

	// Offset within extended attributes.
	//
	// Only valid for OS X, and then only with the resource fork
	// attribute.
	Position uint32
}

A GetxattrRequest asks for the extended attributes associated with r.Node.

func (*GetxattrRequest) Respond 

func (r *GetxattrRequest) Respond(resp *GetxattrResponse)

Respond replies to the request with the given response.

func (*GetxattrRequest) String 

func (r *GetxattrRequest) String() string

type GetxattrResponse 

type GetxattrResponse struct {
	Xattr []byte
}

A GetxattrResponse is the response to a GetxattrRequest.

func (*GetxattrResponse) String 

func (r *GetxattrResponse) String() string

type HandleID 

type HandleID uint64

A HandleID is a number identifying an open directory or file. It only needs to be unique while the directory or file is open.

func (HandleID) String 

func (h HandleID) String() string
type Header struct {
	Conn *Conn     `json:"-"` // connection this request was received on
	ID   RequestID // unique ID for request
	Node NodeID    // file or directory the request is about
	Uid  uint32    // user ID of process making request
	Gid  uint32    // group ID of process making request
	Pid  uint32    // process ID of process making request
	// contains filtered or unexported fields
}

A Header describes the basic information sent in every request.

func (*Header) Hdr 

func (h *Header) Hdr() *Header

func (*Header) RespondError 

func (h *Header) RespondError(err error)

func (*Header) String 

func (h *Header) String() string

type InitFlags 

type InitFlags uint32

The InitFlags are used in the Init exchange. 

const (
	InitAsyncRead     InitFlags = 1 << 0
	InitPosixLocks    InitFlags = 1 << 1
	InitFileOps       InitFlags = 1 << 2
	InitAtomicTrunc   InitFlags = 1 << 3
	InitExportSupport InitFlags = 1 << 4
	InitBigWrites     InitFlags = 1 << 5
	// Do not mask file access modes with umask. Not supported on OS X.
	InitDontMask        InitFlags = 1 << 6
	InitSpliceWrite     InitFlags = 1 << 7
	InitSpliceMove      InitFlags = 1 << 8
	InitSpliceRead      InitFlags = 1 << 9
	InitFlockLocks      InitFlags = 1 << 10
	InitHasIoctlDir     InitFlags = 1 << 11
	InitAutoInvalData   InitFlags = 1 << 12
	InitDoReaddirplus   InitFlags = 1 << 13
	InitReaddirplusAuto InitFlags = 1 << 14
	InitAsyncDIO        InitFlags = 1 << 15
	InitWritebackCache  InitFlags = 1 << 16
	InitNoOpenSupport   InitFlags = 1 << 17

	InitCaseSensitive InitFlags = 1 << 29 // OS X only
	InitVolRename     InitFlags = 1 << 30 // OS X only
	InitXtimes        InitFlags = 1 << 31 // OS X only
)

func (InitFlags) String 

func (fl InitFlags) String() string

type InitRequest 

type InitRequest struct {
	Header `json:"-"`
	Kernel Protocol
	// Maximum readahead in bytes that the kernel plans to use.
	MaxReadahead uint32
	Flags        InitFlags
}

An InitRequest is the first request sent on a FUSE file system.

func (*InitRequest) Respond 

func (r *InitRequest) Respond(resp *InitResponse)

Respond replies to the request with the given response.

func (*InitRequest) String 

func (r *InitRequest) String() string

type InitResponse 

type InitResponse struct {
	Library Protocol
	// Maximum readahead in bytes that the kernel can use. Ignored if
	// greater than InitRequest.MaxReadahead.
	MaxReadahead uint32
	Flags        InitFlags
	// Maximum size of a single write operation.
	// Linux enforces a minimum of 4 KiB.
	MaxWrite uint32
}

An InitResponse is the response to an InitRequest.

func (*InitResponse) String 

func (r *InitResponse) String() string

type InterruptRequest 

type InterruptRequest struct {
	Header `json:"-"`
	IntrID RequestID // ID of the request to be interrupt.
}

An InterruptRequest is a request to interrupt another pending request. The response to that request should return an error status of EINTR.

func (*InterruptRequest) Respond 

func (r *InterruptRequest) Respond()

func (*InterruptRequest) String 

func (r *InterruptRequest) String() string

type LinkRequest 

type LinkRequest struct {
	Header  `json:"-"`
	OldNode NodeID
	NewName string
}

A LinkRequest is a request to create a hard link.

func (*LinkRequest) Respond 

func (r *LinkRequest) Respond(resp *LookupResponse)

func (*LinkRequest) String 

func (r *LinkRequest) String() string

type ListxattrRequest 

type ListxattrRequest struct {
	Header   `json:"-"`
	Size     uint32 // maximum size to return
	Position uint32 // offset within attribute list
}

A ListxattrRequest asks to list the extended attributes associated with r.Node.

func (*ListxattrRequest) Respond 

func (r *ListxattrRequest) Respond(resp *ListxattrResponse)

Respond replies to the request with the given response.

func (*ListxattrRequest) String 

func (r *ListxattrRequest) String() string

type ListxattrResponse 

type ListxattrResponse struct {
	Xattr []byte
}

A ListxattrResponse is the response to a ListxattrRequest.

func (*ListxattrResponse) Append 

func (r *ListxattrResponse) Append(names ...string)

Append adds an extended attribute name to the response.

func (*ListxattrResponse) String 

func (r *ListxattrResponse) String() string

type LookupRequest 

type LookupRequest struct {
	Header `json:"-"`
	Name   string
}

A LookupRequest asks to look up the given name in the directory named by r.Node.

func (*LookupRequest) Respond 

func (r *LookupRequest) Respond(resp *LookupResponse)

Respond replies to the request with the given response.

func (*LookupRequest) String 

func (r *LookupRequest) String() string

type LookupResponse 

type LookupResponse struct {
	Node       NodeID
	Generation uint64
	EntryValid time.Duration
	Attr       Attr
}

A LookupResponse is the response to a LookupRequest.

func (*LookupResponse) String 

func (r *LookupResponse) String() string

type MkdirRequest 

type MkdirRequest struct {
	Header `json:"-"`
	Name   string
	Mode   os.FileMode
	// Umask of the request. Not supported on OS X.
	Umask os.FileMode
}

A MkdirRequest asks to create (but not open) a directory.

func (*MkdirRequest) Respond 

func (r *MkdirRequest) Respond(resp *MkdirResponse)

Respond replies to the request with the given response.

func (*MkdirRequest) String 

func (r *MkdirRequest) String() string

type MkdirResponse 

type MkdirResponse struct {
	LookupResponse
}

A MkdirResponse is the response to a MkdirRequest.

func (*MkdirResponse) String 

func (r *MkdirResponse) String() string

type MknodRequest 

type MknodRequest struct {
	Header `json:"-"`
	Name   string
	Mode   os.FileMode
	Rdev   uint32
	// Umask of the request. Not supported on OS X.
	Umask os.FileMode
}

func (*MknodRequest) Respond 

func (r *MknodRequest) Respond(resp *LookupResponse)

func (*MknodRequest) String 

func (r *MknodRequest) String() string

type MountOption 

type MountOption mountOption

MountOption is passed to Mount to change the behavior of the mount.

func AllowDev 

func AllowDev() MountOption

AllowDev enables interpreting character or block special devices on the filesystem.

func AllowNonEmptyMount 

func AllowNonEmptyMount() MountOption

AllowNonEmptyMount allows the mounting over a non-empty directory.

The files in it will be shadowed by the freshly created mount. By default these mounts are rejected to prevent accidental covering up of data, which could for example prevent automatic backup.

func AllowOther 

func AllowOther() MountOption

AllowOther allows other users to access the file system.

Only one of AllowOther or AllowRoot can be used.

func AllowRoot 

func AllowRoot() MountOption

AllowRoot allows other users to access the file system.

Only one of AllowOther or AllowRoot can be used.

FreeBSD ignores this option.

func AllowSUID 

func AllowSUID() MountOption

AllowSUID allows set-user-identifier or set-group-identifier bits to take effect.

func AsyncRead 

func AsyncRead() MountOption

AsyncRead enables multiple outstanding read requests for the same handle. Without this, there is at most one request in flight at a time.

func DaemonTimeout 

func DaemonTimeout(name string) MountOption

DaemonTimeout sets the time in seconds between a request and a reply before the FUSE mount is declared dead.

OS X and FreeBSD only. Others ignore this option.

func DefaultPermissions 

func DefaultPermissions() MountOption

DefaultPermissions makes the kernel enforce access control based on the file mode (as in chmod).

Without this option, the Node itself decides what is and is not allowed. This is normally ok because FUSE file systems cannot be accessed by other users without AllowOther/AllowRoot.

FreeBSD ignores this option.

func ExclCreate 

func ExclCreate() MountOption

ExclCreate causes O_EXCL flag to be set for only "truly" exclusive creates, i.e. create calls for which the initiator explicitly set the O_EXCL flag.

OSXFUSE expects all create calls to return EEXIST in case the file already exists, regardless of whether O_EXCL was specified or not. To ensure this behavior, it normally sets OpenExclusive for all Create calls, regardless of whether the original call had it set. For distributed filesystems, that may force every file create to be a distributed consensus action, causing undesirable delays.

This option makes the FUSE filesystem see the original flag value, and better decide when to ensure global consensus.

Note that returning EEXIST on existing file create is still expected with OSXFUSE, regardless of the presence of the OpenExclusive flag.

For more information, see https://github.com/osxfuse/osxfuse/issues/209

OS X only. Others ignore this options. Requires OSXFUSE 3.4.1 or newer.

func FSName 

func FSName(name string) MountOption

FSName sets the file system name (also called source) that is visible in the list of mounted file systems.

FreeBSD ignores this option.

func LocalVolume 

func LocalVolume() MountOption

LocalVolume sets the volume to be local (instead of network), changing the behavior of Finder, Spotlight, and such.

OS X only. Others ignore this option.

func MaxReadahead 

func MaxReadahead(n uint32) MountOption

MaxReadahead sets the number of bytes that can be prefetched for sequential reads. The kernel can enforce a maximum value lower than this.

This setting makes the kernel perform speculative reads that do not originate from any client process. This usually tremendously improves read performance.

func NoAppleDouble 

func NoAppleDouble() MountOption

NoAppleDouble makes OSXFUSE disallow files with names used by OS X to store extended attributes on file systems that do not support them natively.

Such file names are: 

._*
.DS_Store

OS X only. Others ignore this option.

func NoAppleXattr 

func NoAppleXattr() MountOption

NoAppleXattr makes OSXFUSE disallow extended attributes with the prefix "com.apple.". This disables persistent Finder state and other such information.

OS X only. Others ignore this option.

func OSXFUSELocations 

func OSXFUSELocations(paths ...OSXFUSEPaths) MountOption

OSXFUSELocations sets where to look for OSXFUSE files. The arguments are all the possible locations. The previous locations are replaced.

Without this option, OSXFUSELocationV3 and OSXFUSELocationV2 are used.

OS X only. Others ignore this option.

func ReadOnly 

func ReadOnly() MountOption

ReadOnly makes the mount read-only.

func Subtype 

func Subtype(fstype string) MountOption

Subtype sets the subtype of the mount. The main type is always `fuse`. The type in a list of mounted file systems will look like `fuse.foo`.

OS X ignores this option. FreeBSD ignores this option.

func VolumeName 

func VolumeName(name string) MountOption

VolumeName sets the volume name shown in Finder.

OS X only. Others ignore this option.

func WritebackCache 

func WritebackCache() MountOption

WritebackCache enables the kernel to buffer writes before sending them to the FUSE server. Without this, writethrough caching is used.

type MountpointDoesNotExistError 

type MountpointDoesNotExistError struct {
	Path string
}

MountpointDoesNotExistError is an error returned when the mountpoint does not exist.

func (*MountpointDoesNotExistError) Error 

func (e *MountpointDoesNotExistError) Error() string

type NodeID 

type NodeID uint64

A NodeID is a number identifying a directory or file. It must be unique among IDs returned in LookupResponses that have not yet been forgotten by ForgetRequests. 

const RootID NodeID = rootID

The RootID identifies the root directory of a FUSE file system.

func (NodeID) String 

func (n NodeID) String() string

type OSXFUSEPaths 

type OSXFUSEPaths struct {
	// Prefix for the device file. At mount time, an incrementing
	// number is suffixed until a free FUSE device is found.
	DevicePrefix string
	// Path of the load helper, used to load the kernel extension if
	// no device files are found.
	Load string
	// Path of the mount helper, used for the actual mount operation.
	Mount string
	// Environment variable used to pass the path to the executable
	// calling the mount helper.
	DaemonVar string
}

OSXFUSEPaths describes the paths used by an installed OSXFUSE version. See OSXFUSELocationV3 for typical values.

type OldVersionError 

type OldVersionError struct {
	Kernel     Protocol
	LibraryMin Protocol
}

func (*OldVersionError) Error 

func (e *OldVersionError) Error() string

type OpenFlags 

type OpenFlags uint32

OpenFlags are the O_FOO flags passed to open/create/etc calls. For example, os.O_WRONLY | os.O_APPEND. 

const (
	// Access modes. These are not 1-bit flags, but alternatives where
	// only one can be chosen. See the IsReadOnly etc convenience
	// methods.
	OpenReadOnly  OpenFlags = syscall.O_RDONLY
	OpenWriteOnly OpenFlags = syscall.O_WRONLY
	OpenReadWrite OpenFlags = syscall.O_RDWR

	// File was opened in append-only mode, all writes will go to end
	// of file. OS X does not provide this information.
	OpenAppend    OpenFlags = syscall.O_APPEND
	OpenCreate    OpenFlags = syscall.O_CREAT
	OpenDirectory OpenFlags = syscall.O_DIRECTORY
	OpenExclusive OpenFlags = syscall.O_EXCL
	OpenNonblock  OpenFlags = syscall.O_NONBLOCK
	OpenSync      OpenFlags = syscall.O_SYNC
	OpenTruncate  OpenFlags = syscall.O_TRUNC
)

Flags that can be seen in OpenRequest.Flags. 

const OpenAccessModeMask OpenFlags = syscall.O_ACCMODE

OpenAccessModeMask is a bitmask that separates the access mode from the other flags in OpenFlags.

func (OpenFlags) IsReadOnly 

func (fl OpenFlags) IsReadOnly() bool

Return true if OpenReadOnly is set.

func (OpenFlags) IsReadWrite 

func (fl OpenFlags) IsReadWrite() bool

Return true if OpenReadWrite is set.

func (OpenFlags) IsWriteOnly 

func (fl OpenFlags) IsWriteOnly() bool

Return true if OpenWriteOnly is set.

func (OpenFlags) String 

func (fl OpenFlags) String() string

type OpenRequest 

type OpenRequest struct {
	Header `json:"-"`
	Dir    bool // is this Opendir?
	Flags  OpenFlags
}

An OpenRequest asks to open a file or directory

func (*OpenRequest) Respond 

func (r *OpenRequest) Respond(resp *OpenResponse)

Respond replies to the request with the given response.

func (*OpenRequest) String 

func (r *OpenRequest) String() string

type OpenResponse 

type OpenResponse struct {
	Handle HandleID
	Flags  OpenResponseFlags
}

A OpenResponse is the response to a OpenRequest.

func (*OpenResponse) String 

func (r *OpenResponse) String() string

type OpenResponseFlags 

type OpenResponseFlags uint32

The OpenResponseFlags are returned in the OpenResponse. 

const (
	OpenDirectIO    OpenResponseFlags = 1 << 0 // bypass page cache for this open file
	OpenKeepCache   OpenResponseFlags = 1 << 1 // don't invalidate the data cache on open
	OpenNonSeekable OpenResponseFlags = 1 << 2 // mark the file as non-seekable (not supported on OS X)

	OpenPurgeAttr OpenResponseFlags = 1 << 30 // OS X
	OpenPurgeUBC  OpenResponseFlags = 1 << 31 // OS X
)

func (OpenResponseFlags) String 

func (fl OpenResponseFlags) String() string

type Protocol 

type Protocol struct {
	Major uint32
	Minor uint32
}

Protocol is a FUSE protocol version number.

func (Protocol) GE 

func (a Protocol) GE(b Protocol) bool

GE returns whether a is greater than or equal to b.

func (Protocol) HasAttrBlockSize 

func (a Protocol) HasAttrBlockSize() bool

HasAttrBlockSize returns whether Attr.BlockSize is respected by the kernel.

func (Protocol) HasGetattrFlags 

func (a Protocol) HasGetattrFlags() bool

HasGetattrFlags returns whether GetattrRequest field Flags is valid.

func (Protocol) HasInvalidate 

func (a Protocol) HasInvalidate() bool

HasInvalidate returns whether InvalidateNode/InvalidateEntry are supported.

func (Protocol) HasOpenNonSeekable 

func (a Protocol) HasOpenNonSeekable() bool

HasOpenNonSeekable returns whether OpenResponse field Flags flag OpenNonSeekable is supported.

func (Protocol) HasReadWriteFlags 

func (a Protocol) HasReadWriteFlags() bool

HasReadWriteFlags returns whether ReadRequest/WriteRequest fields Flags and FileFlags are valid.

func (Protocol) HasUmask 

func (a Protocol) HasUmask() bool

HasUmask returns whether CreateRequest/MkdirRequest/MknodRequest field Umask is valid.

func (Protocol) LT 

func (a Protocol) LT(b Protocol) bool

LT returns whether a is less than b.

func (Protocol) String 

func (p Protocol) String() string

type ReadFlags 

type ReadFlags uint32

The ReadFlags are passed in ReadRequest. 

const (
	// LockOwner field is valid.
	ReadLockOwner ReadFlags = 1 << 1
)

func (ReadFlags) String 

func (fl ReadFlags) String() string

type ReadRequest 

type ReadRequest struct {
	Header    `json:"-"`
	Dir       bool // is this Readdir?
	Handle    HandleID
	Offset    int64
	Size      int
	Flags     ReadFlags
	LockOwner uint64
	FileFlags OpenFlags
}

A ReadRequest asks to read from an open file.

func (*ReadRequest) Respond 

func (r *ReadRequest) Respond(resp *ReadResponse)

Respond replies to the request with the given response.

func (*ReadRequest) String 

func (r *ReadRequest) String() string

type ReadResponse 

type ReadResponse struct {
	Data []byte
}

A ReadResponse is the response to a ReadRequest.

func (*ReadResponse) MarshalJSON 

func (r *ReadResponse) MarshalJSON() ([]byte, error)

func (*ReadResponse) String 

func (r *ReadResponse) String() string

type ReadlinkRequest 

type ReadlinkRequest struct {
	Header `json:"-"`
}

A ReadlinkRequest is a request to read a symlink's target.

func (*ReadlinkRequest) Respond 

func (r *ReadlinkRequest) Respond(target string)

func (*ReadlinkRequest) String 

func (r *ReadlinkRequest) String() string

type ReleaseFlags 

type ReleaseFlags uint32

The ReleaseFlags are used in the Release exchange. 

const (
	ReleaseFlush ReleaseFlags = 1 << 0
)

func (ReleaseFlags) String 

func (fl ReleaseFlags) String() string

type ReleaseRequest 

type ReleaseRequest struct {
	Header       `json:"-"`
	Dir          bool // is this Releasedir?
	Handle       HandleID
	Flags        OpenFlags // flags from OpenRequest
	ReleaseFlags ReleaseFlags
	LockOwner    uint32
}

A ReleaseRequest asks to release (close) an open file handle.

func (*ReleaseRequest) Respond 

func (r *ReleaseRequest) Respond()

Respond replies to the request, indicating that the handle has been released.

func (*ReleaseRequest) String 

func (r *ReleaseRequest) String() string

type RemoveRequest 

type RemoveRequest struct {
	Header `json:"-"`
	Name   string // name of the entry to remove
	Dir    bool   // is this rmdir?
}

A RemoveRequest asks to remove a file or directory from the directory r.Node.

func (*RemoveRequest) Respond 

func (r *RemoveRequest) Respond()

Respond replies to the request, indicating that the file was removed.

func (*RemoveRequest) String 

func (r *RemoveRequest) String() string

type RemovexattrRequest 

type RemovexattrRequest struct {
	Header `json:"-"`
	Name   string // name of extended attribute
}

A RemovexattrRequest asks to remove an extended attribute associated with r.Node.

func (*RemovexattrRequest) Respond 

func (r *RemovexattrRequest) Respond()

Respond replies to the request, indicating that the attribute was removed.

func (*RemovexattrRequest) String 

func (r *RemovexattrRequest) String() string

type RenameRequest 

type RenameRequest struct {
	Header           `json:"-"`
	NewDir           NodeID
	OldName, NewName string
}

A RenameRequest is a request to rename a file.

func (*RenameRequest) Respond 

func (r *RenameRequest) Respond()

func (*RenameRequest) String 

func (r *RenameRequest) String() string

type Request 

type Request interface {
	// Hdr returns the Header associated with this request.
	Hdr() *Header

	// RespondError responds to the request with the given error.
	RespondError(error)

	String() string
}

A Request represents a single FUSE request received from the kernel. Use a type switch to determine the specific kind. A request of unrecognized type will have concrete type *Header.

type RequestID 

type RequestID uint64

A RequestID identifies an active FUSE request.

func (RequestID) String 

func (r RequestID) String() string

type SetattrRequest 

type SetattrRequest struct {
	Header `json:"-"`
	Valid  SetattrValid
	Handle HandleID
	Size   uint64
	Atime  time.Time
	Mtime  time.Time
	Mode   os.FileMode
	Uid    uint32
	Gid    uint32

	// OS X only
	Bkuptime time.Time
	Chgtime  time.Time
	Crtime   time.Time
	Flags    uint32 // see chflags(2)
}

A SetattrRequest asks to change one or more attributes associated with a file, as indicated by Valid.

func (*SetattrRequest) Respond 

func (r *SetattrRequest) Respond(resp *SetattrResponse)

Respond replies to the request with the given response, giving the updated attributes.

func (*SetattrRequest) String 

func (r *SetattrRequest) String() string

type SetattrResponse 

type SetattrResponse struct {
	Attr Attr // file attributes
}

A SetattrResponse is the response to a SetattrRequest.

func (*SetattrResponse) String 

func (r *SetattrResponse) String() string

type SetattrValid 

type SetattrValid uint32

The SetattrValid are bit flags describing which fields in the SetattrRequest are included in the change. 

const (
	SetattrMode   SetattrValid = 1 << 0
	SetattrUid    SetattrValid = 1 << 1
	SetattrGid    SetattrValid = 1 << 2
	SetattrSize   SetattrValid = 1 << 3
	SetattrAtime  SetattrValid = 1 << 4
	SetattrMtime  SetattrValid = 1 << 5
	SetattrHandle SetattrValid = 1 << 6

	// Linux only(?)
	SetattrAtimeNow  SetattrValid = 1 << 7
	SetattrMtimeNow  SetattrValid = 1 << 8
	SetattrLockOwner SetattrValid = 1 << 9 // http://www.mail-archive.com/git-commits-head@vger.kernel.org/msg27852.html

	// OS X only
	SetattrCrtime   SetattrValid = 1 << 28
	SetattrChgtime  SetattrValid = 1 << 29
	SetattrBkuptime SetattrValid = 1 << 30
	SetattrFlags    SetattrValid = 1 << 31
)

func (SetattrValid) Atime 

func (fl SetattrValid) Atime() bool

func (SetattrValid) AtimeNow 

func (fl SetattrValid) AtimeNow() bool

func (SetattrValid) Bkuptime 

func (fl SetattrValid) Bkuptime() bool

func (SetattrValid) Chgtime 

func (fl SetattrValid) Chgtime() bool

func (SetattrValid) Crtime 

func (fl SetattrValid) Crtime() bool

func (SetattrValid) Flags 

func (fl SetattrValid) Flags() bool

func (SetattrValid) Gid 

func (fl SetattrValid) Gid() bool

func (SetattrValid) Handle 

func (fl SetattrValid) Handle() bool

func (SetattrValid) LockOwner 

func (fl SetattrValid) LockOwner() bool

func (SetattrValid) Mode 

func (fl SetattrValid) Mode() bool

func (SetattrValid) Mtime 

func (fl SetattrValid) Mtime() bool

func (SetattrValid) MtimeNow 

func (fl SetattrValid) MtimeNow() bool

func (SetattrValid) Size 

func (fl SetattrValid) Size() bool

func (SetattrValid) String 

func (fl SetattrValid) String() string

func (SetattrValid) Uid 

func (fl SetattrValid) Uid() bool

type SetxattrRequest 

type SetxattrRequest struct {
	Header `json:"-"`

	// Flags can make the request fail if attribute does/not already
	// exist. Unfortunately, the constants are platform-specific and
	// not exposed by Go1.2. Look for XATTR_CREATE, XATTR_REPLACE.
	//
	// TODO improve this later
	//
	// TODO XATTR_CREATE and exist -> EEXIST
	//
	// TODO XATTR_REPLACE and not exist -> ENODATA
	Flags uint32

	// Offset within extended attributes.
	//
	// Only valid for OS X, and then only with the resource fork
	// attribute.
	Position uint32

	Name  string
	Xattr []byte
}

A SetxattrRequest asks to set an extended attribute associated with a file.

func (*SetxattrRequest) Respond 

func (r *SetxattrRequest) Respond()

Respond replies to the request, indicating that the extended attribute was set.

func (*SetxattrRequest) String 

func (r *SetxattrRequest) String() string

type StatfsRequest 

type StatfsRequest struct {
	Header `json:"-"`
}

A StatfsRequest requests information about the mounted file system.

func (*StatfsRequest) Respond 

func (r *StatfsRequest) Respond(resp *StatfsResponse)

Respond replies to the request with the given response.

func (*StatfsRequest) String 

func (r *StatfsRequest) String() string

type StatfsResponse 

type StatfsResponse struct {
	Blocks  uint64 // Total data blocks in file system.
	Bfree   uint64 // Free blocks in file system.
	Bavail  uint64 // Free blocks in file system if you're not root.
	Files   uint64 // Total files in file system.
	Ffree   uint64 // Free files in file system.
	Bsize   uint32 // Block size
	Namelen uint32 // Maximum file name length?
	Frsize  uint32 // Fragment size, smallest addressable data size in the file system.
}

A StatfsResponse is the response to a StatfsRequest.

func (*StatfsResponse) String 

func (r *StatfsResponse) String() string

type SymlinkRequest 

type SymlinkRequest struct {
	Header          `json:"-"`
	NewName, Target string
}

A SymlinkRequest is a request to create a symlink making NewName point to Target.

func (*SymlinkRequest) Respond 

func (r *SymlinkRequest) Respond(resp *SymlinkResponse)

Respond replies to the request, indicating that the symlink was created.

func (*SymlinkRequest) String 

func (r *SymlinkRequest) String() string

type SymlinkResponse 

type SymlinkResponse struct {
	LookupResponse
}

A SymlinkResponse is the response to a SymlinkRequest.

func (*SymlinkResponse) String 

func (r *SymlinkResponse) String() string

type WriteFlags 

type WriteFlags uint32

The WriteFlags are passed in WriteRequest. 

const (
	WriteCache WriteFlags = 1 << 0
	// LockOwner field is valid.
	WriteLockOwner WriteFlags = 1 << 1
)

func (WriteFlags) String 

func (fl WriteFlags) String() string

type WriteRequest 

type WriteRequest struct {
	Header
	Handle    HandleID
	Offset    int64
	Data      []byte
	Flags     WriteFlags
	LockOwner uint64
	FileFlags OpenFlags
}

A WriteRequest asks to write to an open file.

func (*WriteRequest) MarshalJSON 

func (r *WriteRequest) MarshalJSON() ([]byte, error)

func (*WriteRequest) Respond 

func (r *WriteRequest) Respond(resp *WriteResponse)

Respond replies to the request with the given response.

func (*WriteRequest) String 

func (r *WriteRequest) String() string

type WriteResponse 

type WriteResponse struct {
	Size int
}

A WriteResponse replies to a write indicating how many bytes were written.

func (*WriteResponse) String 

func (r *WriteResponse) String() string

Source Files

View all Source files

Directories

Path Synopsis
examples
clockfs
Clockfs implements a file system with the current time in a file.
 Clockfs implements a file system with the current time in a file.
hellofs
Hellofs implements a simple "hello world" file system.
 Hellofs implements a simple "hello world" file system.
fs
bench
Package bench contains benchmarks.
 Package bench contains benchmarks.
fstestutil
fstestutil/record
Package syscallx provides wrappers that make syscalls on various platforms more interoperable.
 Package syscallx provides wrappers that make syscalls on various platforms more interoperable.

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