p9: github.com/hugelgupf/p9/p9 Index | Files

package p9

import "github.com/hugelgupf/p9/p9"

Package p9 is a 9P2000.L implementation.

Servers implement Attacher and File interfaces.

Clients can use Client.

Index

Package Files

buffer.go client.go client_file.go file.go handlers.go messages.go p9.go path_tree.go pool.go server.go transport.go version.go

Constants

const (

    // NoUID is a sentinel used to indicate no valid UID.
    NoUID UID = math.MaxUint32

    // NoGID is a sentinel used to indicate no valid GID.
    NoGID GID = math.MaxUint32
)
const (
    // DefaultMessageSize is a sensible default.
    DefaultMessageSize uint32 = 64 << 10
)

Variables

var AttrMaskAll = AttrMask{
    Mode:        true,
    NLink:       true,
    UID:         true,
    GID:         true,
    RDev:        true,
    ATime:       true,
    MTime:       true,
    CTime:       true,
    INo:         true,
    Size:        true,
    Blocks:      true,
    BTime:       true,
    Gen:         true,
    DataVersion: true,
}

AttrMaskAll is an AttrMask with all fields masked.

var Debug = func(fmt string, v ...interface{}) {}

Debug can be assigned to log.Printf to print messages received and sent.

var ErrBadVersionString = errors.New("bad version string")

ErrBadVersionString indicates that the version string is malformed or unsupported.

var ErrNoValidMessage = errors.New("buffer contained no valid message")

ErrNoValidMessage indicates no valid message could be decoded.

var ErrOutOfFIDs = errors.New("out of FIDs -- messages lost?")

ErrOutOfFIDs indicates no more FIDs are available.

var ErrOutOfTags = errors.New("out of tags -- messages lost?")

ErrOutOfTags indicates no tags are available.

var ErrUnexpectedTag = errors.New("unexpected tag in response")

ErrUnexpectedTag indicates a response with an unexpected tag was received.

var ErrVersionsExhausted = errors.New("exhausted all versions to negotiate")

ErrVersionsExhausted indicates that all versions to negotiate have been exhausted.

func CanOpen Uses

func CanOpen(mode FileMode) bool

CanOpen returns whether this file open can be opened, read and written to.

This includes everything except symlinks and sockets.

func HighestVersionString Uses

func HighestVersionString() string

HighestVersionString returns the highest possible version string that a client may request or a server may support.

func StatToAttr Uses

func StatToAttr(s *internal.Stat_t, req AttrMask) (Attr, AttrMask)

StatToAttr converts a Linux syscall stat structure to an Attr.

func VersionSupportsMultiUser Uses

func VersionSupportsMultiUser(v uint32) bool

VersionSupportsMultiUser returns true if version v supports multi-user fake directory permissions and ID values.

type Attacher Uses

type Attacher interface {
    // Attach returns a new File.
    //
    // The client-side attach will be translate to a series of walks from
    // the file returned by this Attach call.
    Attach() (File, error)
}

Attacher is provided by the server.

type Attr Uses

type Attr struct {
    Mode             FileMode
    UID              UID
    GID              GID
    NLink            NLink
    RDev             Dev
    Size             uint64
    BlockSize        uint64
    Blocks           uint64
    ATimeSeconds     uint64
    ATimeNanoSeconds uint64
    MTimeSeconds     uint64
    MTimeNanoSeconds uint64
    CTimeSeconds     uint64
    CTimeNanoSeconds uint64
    BTimeSeconds     uint64
    BTimeNanoSeconds uint64
    Gen              uint64
    DataVersion      uint64
}

Attr is a set of attributes for getattr.

func (*Attr) Apply Uses

func (a *Attr) Apply(mask SetAttrMask, attr SetAttr)

Apply applies this to the given Attr.

func (Attr) String Uses

func (a Attr) String() string

String implements fmt.Stringer.

type AttrMask Uses

type AttrMask struct {
    Mode        bool
    NLink       bool
    UID         bool
    GID         bool
    RDev        bool
    ATime       bool
    MTime       bool
    CTime       bool
    INo         bool
    Size        bool
    Blocks      bool
    BTime       bool
    Gen         bool
    DataVersion bool
}

AttrMask is a mask of attributes for getattr.

func (AttrMask) Contains Uses

func (a AttrMask) Contains(b AttrMask) bool

Contains returns true if a contains all of the attributes masked as b.

func (AttrMask) Empty Uses

func (a AttrMask) Empty() bool

Empty returns true if no fields are masked.

func (AttrMask) String Uses

func (a AttrMask) String() string

String implements fmt.Stringer.

type Client Uses

type Client struct {
    // contains filtered or unexported fields
}

Client is at least a 9P2000.L client.

func NewClient Uses

func NewClient(conn io.ReadWriteCloser, o ...ClientOpt) (*Client, error)

NewClient creates a new client. It performs a Tversion exchange with the server to assert that messageSize is ok to use.

You should not use the same conn for multiple clients.

func (*Client) Attach Uses

func (c *Client) Attach(name string) (File, error)

Attach attaches to a server.

Note that authentication is not currently supported.

func (*Client) Close Uses

func (c *Client) Close() error

Close closes the underlying connection.

func (*Client) Version Uses

func (c *Client) Version() uint32

Version returns the negotiated 9P2000.L.Google version number.

type ClientOpt Uses

type ClientOpt func(*Client) error

ClientOpt enables optional client configuration.

func WithClientLogger Uses

func WithClientLogger(l ulog.Logger) ClientOpt

WithClientLogger overrides the default logger for the client.

func WithMessageSize Uses

func WithMessageSize(m uint32) ClientOpt

WithMessageSize overrides the default message size.

type ConnError Uses

type ConnError struct {
    // contains filtered or unexported fields
}

ConnError is returned in cases of a connection issue.

This may be treated differently than other errors.

func (ConnError) Error Uses

func (e ConnError) Error() string

func (ConnError) Is Uses

func (e ConnError) Is(target error) bool

Is reports whether any error in err's chain matches target.

type DefaultWalkGetAttr Uses

type DefaultWalkGetAttr struct{}

DefaultWalkGetAttr implements File.WalkGetAttr to return ENOSYS for server-side Files.

func (DefaultWalkGetAttr) WalkGetAttr Uses

func (DefaultWalkGetAttr) WalkGetAttr([]string) ([]QID, File, AttrMask, Attr, error)

WalkGetAttr implements File.WalkGetAttr.

type Dev Uses

type Dev uint64

Dev is the device number of an fs object.

While this type has no utilities, it is useful in order to force linux+amd64 only developers to cast to Dev for the Dev field, which will make their code compatible with other GOARCH and GOOS values.

type Dirent Uses

type Dirent struct {
    // QID is the entry QID.
    QID QID

    // Offset is the offset in the directory.
    //
    // This will be communicated back the original caller.
    Offset uint64

    // Type is the 9P type.
    Type QIDType

    // Name is the name of the entry (i.e. basename).
    Name string
}

Dirent represents a directory entry in File.Readdir.

func (Dirent) String Uses

func (d Dirent) String() string

String implements fmt.Stringer.

type Dirents Uses

type Dirents []Dirent

Dirents is a collection of directory entries.

func (Dirents) Find Uses

func (d Dirents) Find(name string) *Dirent

Find returns a Dirent with the given name if it exists, or nil.

type ErrBadResponse Uses

type ErrBadResponse struct {
    Got  msgType
    Want msgType
}

ErrBadResponse indicates the response didn't match the request.

func (*ErrBadResponse) Error Uses

func (e *ErrBadResponse) Error() string

Error returns a highly descriptive error.

type ErrInvalidMsgType Uses

type ErrInvalidMsgType struct {
    // contains filtered or unexported fields
}

ErrInvalidMsgType is returned when an unsupported message type is found.

func (*ErrInvalidMsgType) Error Uses

func (e *ErrInvalidMsgType) Error() string

Error returns a useful string.

type ErrMessageTooLarge Uses

type ErrMessageTooLarge struct {
    // contains filtered or unexported fields
}

ErrMessageTooLarge indicates the size was larger than reasonable.

func (*ErrMessageTooLarge) Error Uses

func (e *ErrMessageTooLarge) Error() string

Error returns a sensible error.

type FSStat Uses

type FSStat struct {
    // Type is the filesystem type.
    Type uint32

    // BlockSize is the blocksize.
    BlockSize uint32

    // Blocks is the number of blocks.
    Blocks uint64

    // BlocksFree is the number of free blocks.
    BlocksFree uint64

    // BlocksAvailable is the number of blocks *available*.
    BlocksAvailable uint64

    // Files is the number of files available.
    Files uint64

    // FilesFree is the number of free file nodes.
    FilesFree uint64

    // FSID is the filesystem ID.
    FSID uint64

    // NameLength is the maximum name length.
    NameLength uint32
}

FSStat is used by statfs.

type File Uses

type File interface {
    // Walk walks to the path components given in names.
    //
    // Walk returns QIDs in the same order that the names were passed in.
    //
    // An empty list of arguments should return a copy of the current file.
    //
    // On the server, Walk has a read concurrency guarantee.
    Walk(names []string) ([]QID, File, error)

    // WalkGetAttr walks to the next file and returns its maximal set of
    // attributes.
    //
    // Server-side p9.Files may return linux.ENOSYS to indicate that Walk
    // and GetAttr should be used separately to satisfy this request.
    //
    // On the server, WalkGetAttr has a read concurrency guarantee.
    WalkGetAttr([]string) ([]QID, File, AttrMask, Attr, error)

    // StatFS returns information about the file system associated with
    // this file.
    //
    // On the server, StatFS has no concurrency guarantee.
    StatFS() (FSStat, error)

    // GetAttr returns attributes of this node.
    //
    // On the server, GetAttr has a read concurrency guarantee.
    GetAttr(req AttrMask) (QID, AttrMask, Attr, error)

    // SetAttr sets attributes on this node.
    //
    // On the server, SetAttr has a write concurrency guarantee.
    SetAttr(valid SetAttrMask, attr SetAttr) error

    // Close is called when all references are dropped on the server side,
    // and Close should be called by the client to drop all references.
    //
    // For server-side implementations of Close, the error is ignored.
    //
    // Close must be called even when Open has not been called.
    //
    // On the server, Close has no concurrency guarantee.
    Close() error

    // Open must be called prior to using ReadAt, WriteAt, or Readdir. Once
    // Open is called, some operations, such as Walk, will no longer work.
    //
    // On the client, Open should be called only once. The fd return is
    // optional, and may be nil.
    //
    // On the server, Open has a read concurrency guarantee.  Open is
    // guaranteed to be called only once.
    //
    // N.B. The server must resolve any lazy paths when open is called.
    // After this point, read and write may be called on files with no
    // deletion check, so resolving in the data path is not viable.
    Open(mode OpenFlags) (QID, uint32, error)

    // ReadAt reads from this file. Open must be called first.
    //
    // This may return io.EOF in addition to linux.Errno values.
    //
    // On the server, ReadAt has a read concurrency guarantee. See Open for
    // additional requirements regarding lazy path resolution.
    ReadAt(p []byte, offset int64) (int, error)

    // WriteAt writes to this file. Open must be called first.
    //
    // This may return io.EOF in addition to linux.Errno values.
    //
    // On the server, WriteAt has a read concurrency guarantee. See Open
    // for additional requirements regarding lazy path resolution.
    WriteAt(p []byte, offset int64) (int, error)

    // FSync syncs this node. Open must be called first.
    //
    // On the server, FSync has a read concurrency guarantee.
    FSync() error

    // Create creates a new regular file and opens it according to the
    // flags given. This file is already Open.
    //
    // N.B. On the client, the returned file is a reference to the current
    // file, which now represents the created file. This is not the case on
    // the server. These semantics are very subtle and can easily lead to
    // bugs, but are a consequence of the 9P create operation.
    //
    // On the server, Create has a write concurrency guarantee.
    Create(name string, flags OpenFlags, permissions FileMode, uid UID, gid GID) (File, QID, uint32, error)

    // Mkdir creates a subdirectory.
    //
    // On the server, Mkdir has a write concurrency guarantee.
    Mkdir(name string, permissions FileMode, uid UID, gid GID) (QID, error)

    // Symlink makes a new symbolic link.
    //
    // On the server, Symlink has a write concurrency guarantee.
    Symlink(oldName string, newName string, uid UID, gid GID) (QID, error)

    // Link makes a new hard link.
    //
    // On the server, Link has a write concurrency guarantee.
    Link(target File, newName string) error

    // Mknod makes a new device node.
    //
    // On the server, Mknod has a write concurrency guarantee.
    Mknod(name string, mode FileMode, major uint32, minor uint32, uid UID, gid GID) (QID, error)

    // Rename renames the file.
    //
    // Rename will never be called on the server, and RenameAt will always
    // be used instead.
    Rename(newDir File, newName string) error

    // RenameAt renames a given file to a new name in a potentially new
    // directory.
    //
    // oldName must be a name relative to this file, which must be a
    // directory. newName is a name relative to newDir.
    //
    // On the server, RenameAt has a global concurrency guarantee.
    RenameAt(oldName string, newDir File, newName string) error

    // UnlinkAt the given named file.
    //
    // name must be a file relative to this directory.
    //
    // Flags are implementation-specific (e.g. O_DIRECTORY), but are
    // generally Linux unlinkat(2) flags.
    //
    // On the server, UnlinkAt has a write concurrency guarantee.
    UnlinkAt(name string, flags uint32) error

    // Readdir reads directory entries.
    //
    // offset is the entry offset, and count the number of entries to
    // return.
    //
    // This may return io.EOF in addition to linux.Errno values.
    //
    // On the server, Readdir has a read concurrency guarantee.
    Readdir(offset uint64, count uint32) (Dirents, error)

    // Readlink reads the link target.
    //
    // On the server, Readlink has a read concurrency guarantee.
    Readlink() (string, error)

    // Renamed is called when this node is renamed.
    //
    // This may not fail. The file will hold a reference to its parent
    // within the p9 package, and is therefore safe to use for the lifetime
    // of this File (until Close is called).
    //
    // This method should not be called by clients, who should use the
    // relevant Rename methods. (Although the method will be a no-op.)
    //
    // On the server, Renamed has a global concurrency guarantee.
    Renamed(newDir File, newName string)
}

File is a set of operations corresponding to a single node.

Note that on the server side, the server logic places constraints on concurrent operations to make things easier. This may reduce the need for complex, error-prone locking and logic in the backend. These are documented for each method.

There are three different types of guarantees provided:

none: There is no concurrency guarantee. The method may be invoked concurrently with any other method on any other file.

read: The method is guaranteed to be exclusive of any write or global operation that is mutating the state of the directory tree starting at this node. For example, this means creating new files, symlinks, directories or renaming a directory entry (or renaming in to this target), but the method may be called concurrently with other read methods.

write: The method is guaranteed to be exclusive of any read, write or global operation that is mutating the state of the directory tree starting at this node, as described in read above. There may however, be other write operations executing concurrently on other components in the directory tree.

global: The method is guaranteed to be exclusive of any read, write or global operation.

type FileMode Uses

type FileMode uint32

FileMode are flags corresponding to file modes.

These correspond to bits sent over the wire. These also correspond to mode_t bits.

const (
    // FileModeMask is a mask of all the file mode bits of FileMode.
    FileModeMask FileMode = 0170000

    // ModeSocket is an (unused) mode bit for a socket.
    ModeSocket FileMode = 0140000

    // ModeSymlink is a mode bit for a symlink.
    ModeSymlink FileMode = 0120000

    // ModeRegular is a mode bit for regular files.
    ModeRegular FileMode = 0100000

    // ModeBlockDevice is a mode bit for block devices.
    ModeBlockDevice FileMode = 060000

    // ModeDirectory is a mode bit for directories.
    ModeDirectory FileMode = 040000

    // ModeCharacterDevice is a mode bit for a character device.
    ModeCharacterDevice FileMode = 020000

    // ModeNamedPipe is a mode bit for a named pipe.
    ModeNamedPipe FileMode = 010000

    // Read is a mode bit indicating read permission.
    Read FileMode = 04

    // Write is a mode bit indicating write permission.
    Write FileMode = 02

    // Exec is a mode bit indicating exec permission.
    Exec FileMode = 01

    // AllPermissions is a mask with rwx bits set for user, group and others.
    AllPermissions FileMode = 0777

    // Sticky is a mode bit indicating sticky directories.
    Sticky FileMode = 01000
)

func ModeFromOS Uses

func ModeFromOS(mode os.FileMode) FileMode

ModeFromOS returns a FileMode from an os.FileMode.

func (FileMode) FileType Uses

func (m FileMode) FileType() FileMode

FileType returns the file mode without the permission bits.

func (FileMode) IsBlockDevice Uses

func (m FileMode) IsBlockDevice() bool

IsBlockDevice returns true if m represents a character device.

func (FileMode) IsCharacterDevice Uses

func (m FileMode) IsCharacterDevice() bool

IsCharacterDevice returns true if m represents a character device.

func (FileMode) IsDir Uses

func (m FileMode) IsDir() bool

IsDir returns true if m represents a directory.

func (FileMode) IsExecutable Uses

func (m FileMode) IsExecutable() bool

IsExecutable returns true if m represents a file that can be executed.

func (FileMode) IsNamedPipe Uses

func (m FileMode) IsNamedPipe() bool

IsNamedPipe returns true if m represents a named pipe.

func (FileMode) IsReadable Uses

func (m FileMode) IsReadable() bool

IsReadable returns true if m represents a file that can be read.

func (FileMode) IsRegular Uses

func (m FileMode) IsRegular() bool

IsRegular returns true if m is a regular file.

func (FileMode) IsSocket Uses

func (m FileMode) IsSocket() bool

IsSocket returns true if m represents a socket.

func (m FileMode) IsSymlink() bool

IsSymlink returns true if m represents a symlink.

func (FileMode) IsWritable Uses

func (m FileMode) IsWritable() bool

IsWritable returns true if m represents a file that can be written to.

func (FileMode) OSMode Uses

func (m FileMode) OSMode() os.FileMode

OSMode converts a p9.FileMode to an os.FileMode.

func (FileMode) Permissions Uses

func (m FileMode) Permissions() FileMode

Permissions returns just the permission bits of the mode.

func (FileMode) QIDType Uses

func (m FileMode) QIDType() QIDType

QIDType is the most significant byte of the FileMode word, to be used as the Type field of p9.QID.

func (FileMode) Writable Uses

func (m FileMode) Writable() FileMode

Writable returns the mode with write bits added.

type GID Uses

type GID uint32

GID represents a group ID.

func (GID) Ok Uses

func (gid GID) Ok() bool

Ok returns true if gid is not NoGID.

type NLink uint64

NLink is the number of links to this fs object.

While this type has no utilities, it is useful in order to force linux+amd64 only developers to cast to NLink for the NLink field, which will make their code compatible with other GOARCH and GOOS values.

type OpenFlags Uses

type OpenFlags uint32

OpenFlags is the mode passed to Open and Create operations.

These correspond to bits sent over the wire.

const (
    // ReadOnly is a Topen and Tcreate flag indicating read-only mode.
    ReadOnly OpenFlags = 0

    // WriteOnly is a Topen and Tcreate flag indicating write-only mode.
    WriteOnly OpenFlags = 1

    // ReadWrite is a Topen flag indicates read-write mode.
    ReadWrite OpenFlags = 2

    // OpenFlagsModeMask is a mask of valid OpenFlags mode bits.
    OpenFlagsModeMask OpenFlags = 3
)

func (OpenFlags) Mode Uses

func (o OpenFlags) Mode() OpenFlags

Mode returns only the open mode (read-only, read-write, or write-only).

func (OpenFlags) OSFlags Uses

func (o OpenFlags) OSFlags() int

OSFlags converts a p9.OpenFlags to an int compatible with open(2).

func (OpenFlags) String Uses

func (o OpenFlags) String() string

String implements fmt.Stringer.

type QID Uses

type QID struct {
    // Type is the highest order byte of the file mode.
    Type QIDType

    // Version is an arbitrary server version number.
    Version uint32

    // Path is a unique server identifier for this path (e.g. inode).
    Path uint64
}

QID is a unique file identifier.

This may be embedded in other requests and responses.

func (QID) String Uses

func (q QID) String() string

String implements fmt.Stringer.

type QIDGenerator Uses

type QIDGenerator struct {
    // contains filtered or unexported fields
}

QIDGenerator is a simple generator for QIDs that atomically increments Path values.

func (*QIDGenerator) Get Uses

func (q *QIDGenerator) Get(t QIDType) QID

Get returns a new 9P unique ID with a unique Path given a QID type.

While the 9P spec allows Version to be incremented every time the file is modified, we currently do not use the Version member for anything. Hence, it is set to 0.

type QIDType Uses

type QIDType uint8

QIDType represents the file type for QIDs.

QIDType corresponds to the high 8 bits of a Plan 9 file mode.

const (
    // TypeDir represents a directory type.
    TypeDir QIDType = 0x80

    // TypeAppendOnly represents an append only file.
    TypeAppendOnly QIDType = 0x40

    // TypeExclusive represents an exclusive-use file.
    TypeExclusive QIDType = 0x20

    // TypeMount represents a mounted channel.
    TypeMount QIDType = 0x10

    // TypeAuth represents an authentication file.
    TypeAuth QIDType = 0x08

    // TypeTemporary represents a temporary file.
    TypeTemporary QIDType = 0x04

    // TypeSymlink represents a symlink.
    TypeSymlink QIDType = 0x02

    // TypeLink represents a hard link.
    TypeLink QIDType = 0x01

    // TypeRegular represents a regular file.
    TypeRegular QIDType = 0x00
)

type Server Uses

type Server struct {
    // contains filtered or unexported fields
}

Server is a 9p2000.L server.

func NewServer Uses

func NewServer(attacher Attacher, o ...ServerOpt) *Server

NewServer returns a new server.

func (*Server) Handle Uses

func (s *Server) Handle(t io.ReadCloser, r io.WriteCloser) error

Handle handles a single connection.

func (*Server) Serve Uses

func (s *Server) Serve(serverSocket net.Listener) error

Serve handles requests from the bound socket.

The passed serverSocket _must_ be created in packet mode.

type ServerOpt Uses

type ServerOpt func(s *Server)

ServerOpt is an optional config for a new server.

func WithServerLogger Uses

func WithServerLogger(l ulog.Logger) ServerOpt

WithServerLogger overrides the default logger for the server.

type SetAttr Uses

type SetAttr struct {
    Permissions      FileMode
    UID              UID
    GID              GID
    Size             uint64
    ATimeSeconds     uint64
    ATimeNanoSeconds uint64
    MTimeSeconds     uint64
    MTimeNanoSeconds uint64
}

SetAttr specifies a set of attributes for a setattr.

func (SetAttr) String Uses

func (s SetAttr) String() string

String implements fmt.Stringer.

type SetAttrMask Uses

type SetAttrMask struct {
    Permissions        bool
    UID                bool
    GID                bool
    Size               bool
    ATime              bool
    MTime              bool
    CTime              bool
    ATimeNotSystemTime bool
    MTimeNotSystemTime bool
}

SetAttrMask specifies a valid mask for setattr.

func (SetAttrMask) Empty Uses

func (s SetAttrMask) Empty() bool

Empty returns true if no fields are masked.

func (SetAttrMask) IsSubsetOf Uses

func (s SetAttrMask) IsSubsetOf(m SetAttrMask) bool

IsSubsetOf returns whether s is a subset of m.

func (SetAttrMask) String Uses

func (s SetAttrMask) String() string

String implements fmt.Stringer.

type UID Uses

type UID uint32

UID represents a user ID.

func (UID) Ok Uses

func (uid UID) Ok() bool

Ok returns true if uid is not NoUID.

Package p9 imports 20 packages (graph) and is imported by 10 packages. Updated 2020-07-28. Refresh now. Tools for package owners.