sftp

package module
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 Go to latest Published: Dec 6, 2023 License: BSD-2-Clause Imports: 24 Imported by: 0

README

sftp

The sftp package provides support for file system operations on remote ssh servers using the SFTP subsystem. It also implements an SFTP server for serving files from the filesystem.

CI Status Go Reference

usage and examples

See https://pkg.go.dev/github.com/pkg/sftp for examples and usage.

The basic operation of the package mirrors the facilities of the os package.

The Walker interface for directory traversal is heavily inspired by Keith Rarick's fs package.

roadmap

  • There is way too much duplication in the Client methods. If there was an unmarshal(interface{}) method this would reduce a heap of the duplication.

contributing

We welcome pull requests, bug fixes and issue reports.

Before proposing a large change, first please discuss your change by raising an issue.

For API/code bugs, please include a small, self contained code example to reproduce the issue. For pull requests, remember test coverage.

We try to handle issues and pull requests with a 0 open philosophy. That means we will try to address the submission as soon as possible and will work toward a resolution. If progress can no longer be made (eg. unreproducible bug) or stops (eg. unresponsive submitter), we will close the bug.

Thanks.

Documentation

Overview

Package sftp implements the SSH File Transfer Protocol as described in https://filezilla-project.org/specs/draft-ietf-secsh-filexfer-02.txt

Example 
package main

import (
	"log"

	"github.com/viaTunnel/sftp"
	"golang.org/x/crypto/ssh"
)

func main() {
	var conn *ssh.Client

	// open an SFTP session over an existing ssh connection.
	client, err := sftp.NewClient(conn)
	if err != nil {
		log.Fatal(err)
	}
	defer client.Close()

	// walk a directory
	w := client.Walk("/home/user")
	for w.Step() {
		if w.Err() != nil {
			continue
		}
		log.Println(w.Path())
	}

	// leave your mark
	f, err := client.Create("hello.txt")
	if err != nil {
		log.Fatal(err)
	}
	if _, err := f.Write([]byte("Hello world!")); err != nil {
		log.Fatal(err)
	}
	f.Close()

	// check it's there
	fi, err := client.Lstat("hello.txt")
	if err != nil {
		log.Fatal(err)
	}
	log.Println(fi)
}

Output:

Index

Examples

Constants

View Source 
const (
	ErrSSHFxOk               = fxerr(sshFxOk)
	ErrSSHFxEOF              = fxerr(sshFxEOF)
	ErrSSHFxNoSuchFile       = fxerr(sshFxNoSuchFile)
	ErrSSHFxPermissionDenied = fxerr(sshFxPermissionDenied)
	ErrSSHFxFailure          = fxerr(sshFxFailure)
	ErrSSHFxBadMessage       = fxerr(sshFxBadMessage)
	ErrSSHFxNoConnection     = fxerr(sshFxNoConnection)
	ErrSSHFxConnectionLost   = fxerr(sshFxConnectionLost)
	ErrSSHFxOpUnsupported    = fxerr(sshFxOPUnsupported)
)

Error types that match the SFTP's SSH_FXP_STATUS codes. Gives you more direct control of the errors being sent vs. letting the library work them out from the standard os/io errors.

View Source 
const (
	ErrSshFxOk               = ErrSSHFxOk
	ErrSshFxEof              = ErrSSHFxEOF
	ErrSshFxNoSuchFile       = ErrSSHFxNoSuchFile
	ErrSshFxPermissionDenied = ErrSSHFxPermissionDenied
	ErrSshFxFailure          = ErrSSHFxFailure
	ErrSshFxBadMessage       = ErrSSHFxBadMessage
	ErrSshFxNoConnection     = ErrSSHFxNoConnection
	ErrSshFxConnectionLost   = ErrSSHFxConnectionLost
	ErrSshFxOpUnsupported    = ErrSSHFxOpUnsupported
)

Deprecated error types, these are aliases for the new ones, please use the new ones directly

View Source 
const EBADF = syscall.EBADF
View Source 
const S_IFMT = syscall.S_IFMT
View Source 
const (
	// SftpServerWorkerCount defines the number of workers for the SFTP server
	SftpServerWorkerCount = 8
)

Variables

View Source 
var (
	// ErrInternalInconsistency indicates the packets sent and the data queued to be
	// written to the file don't match up. It is an unusual error and usually is
	// caused by bad behavior server side or connection issues. The error is
	// limited in scope to the call where it happened, the client object is still
	// OK to use as long as the connection is still open.
	ErrInternalInconsistency = errors.New("internal inconsistency")
	// InternalInconsistency alias for ErrInternalInconsistency.
	//
	// Deprecated: please use ErrInternalInconsistency
	InternalInconsistency = ErrInternalInconsistency
)
View Source 
var ErrBadPattern = path.ErrBadPattern

ErrBadPattern indicates a globbing pattern was malformed.

View Source 
var MaxFilelist int64 = 100

MaxFilelist is the max number of files to return in a readdir batch.

Functions

func Join 

func Join(elem ...string) string

Join joins any number of path elements into a single path, separating them with slashes.

This is an alias for path.Join from the standard library, offered so that callers need not import the path package. For details, see https://golang.org/pkg/path/#Join.

func Match 

func Match(pattern, name string) (matched bool, err error)

Match reports whether name matches the shell pattern.

This is an alias for path.Match from the standard library, offered so that callers need not import the path package. For details, see https://golang.org/pkg/path/#Match.

func SetSFTPExtensions 

func SetSFTPExtensions(extensions ...string) error

SetSFTPExtensions allows to customize the supported server extensions. See the variable supportedSFTPExtensions for supported extensions. This method accepts a slice of sshExtensionPair names for example 'hardlink@openssh.com'. If an invalid extension is given an error will be returned and nothing will be changed

func Split 

func Split(p string) (dir, file string)

Split splits the path p immediately following the final slash, separating it into a directory and file name component.

This is an alias for path.Split from the standard library, offered so that callers need not import the path package. For details, see https://golang.org/pkg/path/#Split.

Types

type Client 

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

Client represents an SFTP session on a *ssh.ClientConn SSH connection. Multiple Clients can be active on a single SSH connection, and a Client may be called concurrently from multiple Goroutines.

Client implements the github.com/kr/fs.FileSystem interface.

func NewClient 

func NewClient(conn *ssh.Client, opts ...ClientOption) (*Client, error)

NewClient creates a new SFTP client on conn, using zero or more option functions.

func NewClientPipe 

func NewClientPipe(rd io.Reader, wr io.WriteCloser, opts ...ClientOption) (*Client, error)

NewClientPipe creates a new SFTP client given a Reader and a WriteCloser. This can be used for connecting to an SFTP server over TCP/TLS or by using the system's ssh client program (e.g. via exec.Command).

Example 
package main

import (
	"fmt"
	"log"
	"os"
	"os/exec"

	"github.com/viaTunnel/sftp"
)

func main() {
	// Connect to a remote host and request the sftp subsystem via the 'ssh'
	// command.  This assumes that passwordless login is correctly configured.
	cmd := exec.Command("ssh", "example.com", "-s", "sftp")

	// send errors from ssh to stderr
	cmd.Stderr = os.Stderr

	// get stdin and stdout
	wr, err := cmd.StdinPipe()
	if err != nil {
		log.Fatal(err)
	}
	rd, err := cmd.StdoutPipe()
	if err != nil {
		log.Fatal(err)
	}

	// start the process
	if err := cmd.Start(); err != nil {
		log.Fatal(err)
	}
	defer cmd.Wait()

	// open the SFTP session
	client, err := sftp.NewClientPipe(rd, wr)
	if err != nil {
		log.Fatal(err)
	}

	// read a directory
	list, err := client.ReadDir("/")
	if err != nil {
		log.Fatal(err)
	}

	// print contents
	for _, item := range list {
		fmt.Println(item.Name())
	}

	// close the connection
	client.Close()
}

Output:

func (*Client) Chmod 

func (c *Client) Chmod(path string, mode os.FileMode) error

Chmod changes the permissions of the named file.

Chmod does not apply a umask, because even retrieving the umask is not possible in a portable way without causing a race condition. Callers should mask off umask bits, if desired.

func (*Client) Chown 

func (c *Client) Chown(path string, uid, gid int) error

Chown changes the user and group owners of the named file.

func (*Client) Chtimes 

func (c *Client) Chtimes(path string, atime time.Time, mtime time.Time) error

Chtimes changes the access and modification times of the named file.

func (*Client) Close 

func (c *Client) Close() error

Close closes the SFTP session.

func (*Client) Create 

func (c *Client) Create(path string) (*File, error)

Create creates the named file mode 0666 (before umask), truncating it if it already exists. If successful, methods on the returned File can be used for I/O; the associated file descriptor has mode O_RDWR. If you need more control over the flags/mode used to open the file see client.OpenFile.

Note that some SFTP servers (eg. AWS Transfer) do not support opening files read/write at the same time. For those services you will need to use `client.OpenFile(os.O_WRONLY|os.O_CREATE|os.O_TRUNC)`.

func (*Client) Getwd 

func (c *Client) Getwd() (string, error)

Getwd returns the current working directory of the server. Operations involving relative paths will be based at this location.

func (*Client) Glob 

func (c *Client) Glob(pattern string) (matches []string, err error)

Glob returns the names of all files matching pattern or nil if there is no matching file. The syntax of patterns is the same as in Match. The pattern may describe hierarchical names such as /usr/*/bin/ed.

Glob ignores file system errors such as I/O errors reading directories. The only possible returned error is ErrBadPattern, when pattern is malformed.

func (*Client) HasExtension 

func (c *Client) HasExtension(name string) (string, bool)

HasExtension checks whether the server supports a named extension.

The first return value is the extension data reported by the server (typically a version number).

func (*Client) Join 

func (c *Client) Join(elem ...string) string

Join joins any number of path elements into a single path, adding a separating slash if necessary. The result is Cleaned; in particular, all empty strings are ignored. 

func (c *Client) Link(oldname, newname string) error

Link creates a hard link at 'newname', pointing at the same inode as 'oldname'

func (*Client) Lstat 

func (c *Client) Lstat(p string) (os.FileInfo, error)

Lstat returns a FileInfo structure describing the file specified by path 'p'. If 'p' is a symbolic link, the returned FileInfo structure describes the symbolic link.

func (*Client) Mkdir 

func (c *Client) Mkdir(path string) error

Mkdir creates the specified directory. An error will be returned if a file or directory with the specified path already exists, or if the directory's parent folder does not exist (the method cannot create complete paths).

Example (Parents) 
package main

import (
	"fmt"
	"log"
	"os"
	"path"
	"strings"

	"github.com/viaTunnel/sftp"
	"golang.org/x/crypto/ssh"
)

func main() {
	// Example of mimicing 'mkdir --parents'; I.E. recursively create
	// directoryies and don't error if any directories already exists.
	var conn *ssh.Client

	client, err := sftp.NewClient(conn)
	if err != nil {
		log.Fatal(err)
	}
	defer client.Close()

	sshFxFailure := uint32(4)
	mkdirParents := func(client *sftp.Client, dir string) (err error) {
		var parents string

		if path.IsAbs(dir) {
			// Otherwise, an absolute path given below would be turned in to a relative one
			// by splitting on "/"
			parents = "/"
		}

		for _, name := range strings.Split(dir, "/") {
			if name == "" {
				// Paths with double-/ in them should just move along
				// this will also catch the case of the first character being a "/", i.e. an absolute path
				continue
			}
			parents = path.Join(parents, name)
			err = client.Mkdir(parents)
			if status, ok := err.(*sftp.StatusError); ok {
				if status.Code == sshFxFailure {
					var fi os.FileInfo
					fi, err = client.Stat(parents)
					if err == nil {
						if !fi.IsDir() {
							return fmt.Errorf("file exists: %s", parents)
						}
					}
				}
			}
			if err != nil {
				break
			}
		}
		return err
	}

	err = mkdirParents(client, "/tmp/foo/bar")
	if err != nil {
		log.Fatal(err)
	}
}

Output:

func (*Client) MkdirAll 

func (c *Client) MkdirAll(path string) error

MkdirAll creates a directory named path, along with any necessary parents, and returns nil, or else returns an error. If path is already a directory, MkdirAll does nothing and returns nil. If path contains a regular file, an error is returned

func (*Client) Open 

func (c *Client) Open(path string) (*File, error)

Open opens the named file for reading. If successful, methods on the returned file can be used for reading; the associated file descriptor has mode O_RDONLY.

func (*Client) OpenFile 

func (c *Client) OpenFile(path string, f int) (*File, error)

OpenFile is the generalized open call; most users will use Open or Create instead. It opens the named file with specified flag (O_RDONLY etc.). If successful, methods on the returned File can be used for I/O.

func (*Client) PosixRename 

func (c *Client) PosixRename(oldname, newname string) error

PosixRename renames a file using the posix-rename@openssh.com extension which will replace newname if it already exists.

func (*Client) ReadDir 

func (c *Client) ReadDir(p string) ([]os.FileInfo, error)

ReadDir reads the directory named by p and returns a list of directory entries.

func (*Client) ReadDirContext 

func (c *Client) ReadDirContext(ctx context.Context, p string) ([]os.FileInfo, error)

ReadDirContext reads the directory named by p and returns a list of directory entries. The passed context can be used to cancel the operation returning all entries listed up to the cancellation. 

func (c *Client) ReadLink(p string) (string, error)

ReadLink reads the target of a symbolic link.

func (*Client) RealPath 

func (c *Client) RealPath(path string) (string, error)

RealPath can be used to have the server canonicalize any given path name to an absolute path.

This is useful for converting path names containing ".." components, or relative pathnames without a leading slash into absolute paths.

func (*Client) Remove 

func (c *Client) Remove(path string) error

Remove removes the specified file or directory. An error will be returned if no file or directory with the specified path exists, or if the specified directory is not empty.

func (*Client) RemoveAll 

func (c *Client) RemoveAll(path string) error

RemoveAll delete files recursively in the directory and Recursively delete subdirectories. An error will be returned if no file or directory with the specified path exists

func (*Client) RemoveDirectory 

func (c *Client) RemoveDirectory(path string) error

RemoveDirectory removes a directory path.

func (*Client) Rename 

func (c *Client) Rename(oldname, newname string) error

Rename renames a file.

func (*Client) Stat 

func (c *Client) Stat(p string) (os.FileInfo, error)

Stat returns a FileInfo structure describing the file specified by path 'p'. If 'p' is a symbolic link, the returned FileInfo structure describes the referent file.

func (*Client) StatVFS 

func (c *Client) StatVFS(path string) (*StatVFS, error)

StatVFS retrieves VFS statistics from a remote host.

It implements the statvfs@openssh.com SSH_FXP_EXTENDED feature from http://www.opensource.apple.com/source/OpenSSH/OpenSSH-175/openssh/PROTOCOL?txt. 

func (c *Client) Symlink(oldname, newname string) error

Symlink creates a symbolic link at 'newname', pointing at target 'oldname'

func (*Client) Truncate 

func (c *Client) Truncate(path string, size int64) error

Truncate sets the size of the named file. Although it may be safely assumed that if the size is less than its current size it will be truncated to fit, the SFTP protocol does not specify what behavior the server should do when setting size greater than the current size.

func (*Client) Wait 

func (c *Client) Wait() error

Wait blocks until the conn has shut down, and return the error causing the shutdown. It can be called concurrently from multiple goroutines.

func (*Client) Walk 

func (c *Client) Walk(root string) *fs.Walker

Walk returns a new Walker rooted at root.

type ClientOption 

type ClientOption func(*Client) error

A ClientOption is a function which applies configuration to a Client.

func MaxConcurrentRequestsPerFile 

func MaxConcurrentRequestsPerFile(n int) ClientOption

MaxConcurrentRequestsPerFile sets the maximum concurrent requests allowed for a single file.

The default maximum concurrent requests is 64.

func MaxPacket 

func MaxPacket(size int) ClientOption

MaxPacket sets the maximum size of the payload, measured in bytes. This option only accepts sizes servers should support, ie. <= 32768 bytes. This is a synonym for MaxPacketChecked that provides backward compatibility.

If you get the error "failed to send packet header: EOF" when copying a large file, try lowering this number.

The default packet size is 32768 bytes.

func MaxPacketChecked 

func MaxPacketChecked(size int) ClientOption

MaxPacketChecked sets the maximum size of the payload, measured in bytes. This option only accepts sizes servers should support, ie. <= 32768 bytes.

If you get the error "failed to send packet header: EOF" when copying a large file, try lowering this number.

The default packet size is 32768 bytes.

func MaxPacketUnchecked 

func MaxPacketUnchecked(size int) ClientOption

MaxPacketUnchecked sets the maximum size of the payload, measured in bytes. It accepts sizes larger than the 32768 bytes all servers should support. Only use a setting higher than 32768 if your application always connects to the same server or after sufficiently broad testing.

If you get the error "failed to send packet header: EOF" when copying a large file, try lowering this number.

The default packet size is 32768 bytes.

func UseConcurrentReads 

func UseConcurrentReads(value bool) ClientOption

UseConcurrentReads allows the Client to perform concurrent Reads.

Concurrent reads are generally safe to use and not using them will degrade performance, so this option is enabled by default.

When enabled, WriteTo will use Stat/Fstat to get the file size and determines how many concurrent workers to use. Some "read once" servers will delete the file if they receive a stat call on an open file and then the download will fail. Disabling concurrent reads you will be able to download files from these servers. If concurrent reads are disabled, the UseFstat option is ignored.

func UseConcurrentWrites 

func UseConcurrentWrites(value bool) ClientOption

UseConcurrentWrites allows the Client to perform concurrent Writes.

Using concurrency while doing writes, requires special consideration. A write to a later offset in a file after an error, could end up with a file length longer than what was successfully written.

When using this option, if you receive an error during `io.Copy` or `io.WriteTo`, you may need to `Truncate` the target Writer to avoid “holes” in the data written.

func UseFstat 

func UseFstat(value bool) ClientOption

UseFstat sets whether to use Fstat or Stat when File.WriteTo is called (usually when copying files). Some servers limit the amount of open files and calling Stat after opening the file will throw an error From the server. Setting this flag will call Fstat instead of Stat which is suppose to be called on an open file handle.

It has been found that that with IBM Sterling SFTP servers which have "extractability" level set to 1 which means only 1 file can be opened at any given time.

If the server you are working with still has an issue with both Stat and Fstat calls you can always open a file and read it until the end.

Another reason to read the file until its end and Fstat doesn't work is that in some servers, reading a full file will automatically delete the file as some of these mainframes map the file to a message in a queue. Once the file has been read it will get deleted.

type File 

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

File represents a remote file.

func (*File) Chmod 

func (f *File) Chmod(mode os.FileMode) error

Chmod changes the permissions of the current file.

See Client.Chmod for details.

func (*File) Chown 

func (f *File) Chown(uid, gid int) error

Chown changes the uid/gid of the current file.

func (*File) Close 

func (f *File) Close() error

Close closes the File, rendering it unusable for I/O. It returns an error, if any.

func (*File) Name 

func (f *File) Name() string

Name returns the name of the file as presented to Open or Create.

func (*File) Read 

func (f *File) Read(b []byte) (int, error)

Read reads up to len(b) bytes from the File. It returns the number of bytes read and an error, if any. Read follows io.Reader semantics, so when Read encounters an error or EOF condition after successfully reading n > 0 bytes, it returns the number of bytes read.

To maximise throughput for transferring the entire file (especially over high latency links) it is recommended to use WriteTo rather than calling Read multiple times. io.Copy will do this automatically.

func (*File) ReadAt 

func (f *File) ReadAt(b []byte, off int64) (int, error)

ReadAt reads up to len(b) byte from the File at a given offset `off`. It returns the number of bytes read and an error, if any. ReadAt follows io.ReaderAt semantics, so the file offset is not altered during the read.

func (*File) ReadFrom 

func (f *File) ReadFrom(r io.Reader) (int64, error)

ReadFrom reads data from r until EOF and writes it to the file. The return value is the number of bytes read. Any error except io.EOF encountered during the read is also returned.

This method is preferred over calling Write multiple times to maximise throughput for transferring the entire file, especially over high-latency links.

Example (Bufio) 
package main

import (
	"bufio"
	"io"

	"github.com/viaTunnel/sftp"
)

func main() {
	// Using Bufio to buffer writes going to an sftp.File won't buffer as it
	// skips buffering if the underlying writer support ReadFrom. The
	// workaround is to wrap your writer in a struct that only implements
	// io.Writer.
	//
	// For background see github.com/pkg/sftp/issues/125

	var data_source io.Reader
	var f *sftp.File
	type writerOnly struct{ io.Writer }
	bw := bufio.NewWriter(writerOnly{f}) // no ReadFrom()
	bw.ReadFrom(data_source)
}

Output:

func (*File) ReadFromWithConcurrency 

func (f *File) ReadFromWithConcurrency(r io.Reader, concurrency int) (read int64, err error)

ReadFromWithConcurrency implements ReaderFrom, but uses the given concurrency to issue multiple requests at the same time.

Giving a concurrency of less than one will default to the Client’s max concurrency.

Otherwise, the given concurrency will be capped by the Client's max concurrency.

func (*File) Seek 

func (f *File) Seek(offset int64, whence int) (int64, error)

Seek implements io.Seeker by setting the client offset for the next Read or Write. It returns the next offset read. Seeking before or after the end of the file is undefined. Seeking relative to the end calls Stat.

func (*File) Stat 

func (f *File) Stat() (os.FileInfo, error)

Stat returns the FileInfo structure describing file. If there is an error.

func (*File) Sync 

func (f *File) Sync() error

Sync requests a flush of the contents of a File to stable storage.

Sync requires the server to support the fsync@openssh.com extension.

func (*File) Truncate 

func (f *File) Truncate(size int64) error

Truncate sets the size of the current file. Although it may be safely assumed that if the size is less than its current size it will be truncated to fit, the SFTP protocol does not specify what behavior the server should do when setting size greater than the current size. We send a SSH_FXP_FSETSTAT here since we have a file handle

func (*File) Write 

func (f *File) Write(b []byte) (int, error)

Write writes len(b) bytes to the File. It returns the number of bytes written and an error, if any. Write returns a non-nil error when n != len(b).

To maximise throughput for transferring the entire file (especially over high latency links) it is recommended to use ReadFrom rather than calling Write multiple times. io.Copy will do this automatically.

func (*File) WriteAt 

func (f *File) WriteAt(b []byte, off int64) (written int, err error)

WriteAt writes up to len(b) byte to the File at a given offset `off`. It returns the number of bytes written and an error, if any. WriteAt follows io.WriterAt semantics, so the file offset is not altered during the write.

func (*File) WriteTo 

func (f *File) WriteTo(w io.Writer) (written int64, err error)

WriteTo writes the file to the given Writer. The return value is the number of bytes written. Any error encountered during the write is also returned.

This method is preferred over calling Read multiple times to maximise throughput for transferring the entire file, especially over high latency links.

type FileAttrFlags 

type FileAttrFlags struct {
	Size, UidGid, Permissions, Acmodtime bool
}

FileAttrFlags that indicate whether SFTP file attributes were passed. When a flag is true the corresponding attribute should be available from the FileStat object returned by Attributes method. Used with SetStat.

type FileCmder 

type FileCmder interface {
	Filecmd(*Request) error
}

FileCmder should return an error Note in cases of an error, the error text will be sent to the client. Called for Methods: Setstat, Rename, Rmdir, Mkdir, Link, Symlink, Remove

type FileInfoExtendedData 

type FileInfoExtendedData interface {
	os.FileInfo
	Extended() []StatExtended
}

FileInfoUidGid extends os.FileInfo and adds a callbacks for extended data retrieval.

type FileInfoUidGid 

type FileInfoUidGid interface {
	os.FileInfo
	Uid() uint32
	Gid() uint32
}

FileInfoUidGid extends os.FileInfo and adds callbacks for Uid and Gid retrieval, as an alternative to *syscall.Stat_t objects on unix systems.

type FileLister 

type FileLister interface {
	Filelist(*Request) (ListerAt, error)
}

FileLister should return an object that fulfils the ListerAt interface Note in cases of an error, the error text will be sent to the client. Called for Methods: List, Stat, Readlink

Since Filelist returns an os.FileInfo, this can make it non-ideal for implementing Readlink. This is because the Name receiver method defined by that interface defines that it should only return the base name. However, Readlink is required to be capable of returning essentially any arbitrary valid path relative or absolute. In order to implement this more expressive requirement, implement ReadlinkFileLister which will then be used instead.

type FileOpenFlags 

type FileOpenFlags struct {
	Read, Write, Append, Creat, Trunc, Excl bool
}

FileOpenFlags defines Open and Write Flags. Correlate directly with with os.OpenFile flags (https://golang.org/pkg/os/#pkg-constants).

type FileReader 

type FileReader interface {
	Fileread(*Request) (io.ReaderAt, error)
}

FileReader should return an io.ReaderAt for the filepath Note in cases of an error, the error text will be sent to the client. Called for Methods: Get

type FileStat 

type FileStat struct {
	Size     uint64
	Mode     uint32
	Mtime    uint32
	Atime    uint32
	UID      uint32
	GID      uint32
	Extended []StatExtended
}

FileStat holds the original unmarshalled values from a call to READDIR or *STAT. It is exported for the purposes of accessing the raw values via os.FileInfo.Sys(). It is also used server side to store the unmarshalled values for SetStat.

func (FileStat) FileMode 

func (a FileStat) FileMode() os.FileMode

FileMode returns the Mode SFTP file attributes wrapped as os.FileMode

type FileWriter 

type FileWriter interface {
	Filewrite(*Request) (io.WriterAt, error)
}

FileWriter should return an io.WriterAt for the filepath.

The request server code will call Close() on the returned io.WriterAt object if an io.Closer type assertion succeeds. Note in cases of an error, the error text will be sent to the client. Note when receiving an Append flag it is important to not open files using O_APPEND if you plan to use WriteAt, as they conflict. Called for Methods: Put, Open

type Handlers 

type Handlers struct {
	FileGet  FileReader
	FilePut  FileWriter
	FileCmd  FileCmder
	FileList FileLister
}

Handlers contains the 4 SFTP server request handlers.

func InMemHandler 

func InMemHandler() Handlers

InMemHandler returns a Hanlders object with the test handlers.

type ListerAt 

type ListerAt interface {
	ListAt([]os.FileInfo, int64) (int, error)
}

ListerAt does for file lists what io.ReaderAt does for files, i.e. a []os.FileInfo buffer is passed to the ListAt function and the entries that are populated in the buffer will be passed to the client.

ListAt should return the number of entries copied and an io.EOF error if at end of list. This is testable by comparing how many you copied to how many could be copied (eg. n < len(ls) below). The copy() builtin is best for the copying.

Uid and gid information will on unix systems be retrieved from os.FileInfo.Sys if this function returns a syscall.Stat_t when called on a populated entry. Alternatively, if the entry implements FileInfoUidGid, it will be used for uid and gid information.

If a populated entry implements FileInfoExtendedData, extended attributes will also be returned to the client.

Note in cases of an error, the error text will be sent to the client.

type LstatFileLister 

type LstatFileLister interface {
	FileLister
	Lstat(*Request) (ListerAt, error)
}

LstatFileLister is a FileLister that implements the Lstat method. If this interface is implemented Lstat requests will call it otherwise they will be handled in the same way as Stat

type NameLookupFileLister 

type NameLookupFileLister interface {
	FileLister
	LookupUserName(string) string
	LookupGroupName(string) string
}

NameLookupFileLister is a FileLister that implmeents the LookupUsername and LookupGroupName methods. If this interface is implemented, then longname ls formatting will use these to convert usernames and groupnames.

type OpenFileWriter 

type OpenFileWriter interface {
	FileWriter
	OpenFile(*Request) (WriterAtReaderAt, error)
}

OpenFileWriter is a FileWriter that implements the generic OpenFile method. You need to implement this optional interface if you want to be able to read and write from/to the same handle. Called for Methods: Open

type PosixRenameFileCmder 

type PosixRenameFileCmder interface {
	FileCmder
	PosixRename(*Request) error
}

PosixRenameFileCmder is a FileCmder that implements the PosixRename method. If this interface is implemented PosixRename requests will call it otherwise they will be handled in the same way as Rename

type ReadlinkFileLister 

type ReadlinkFileLister interface {
	FileLister
	Readlink(string) (string, error)
}

ReadlinkFileLister is a FileLister that implements the Readlink method. By implementing the Readlink method, it is possible to return any arbitrary valid path relative or absolute. This allows giving a better response than via the default FileLister (which is limited to os.FileInfo, whose Name method should only return the base name of a file)

type RealPathFileLister 

type RealPathFileLister interface {
	FileLister
	RealPath(string) (string, error)
}

RealPathFileLister is a FileLister that implements the Realpath method. The built-in RealPath implementation does not resolve symbolic links. By implementing this interface you can customize the returned path and, for example, resolve symbolinc links if needed for your use case. You have to return an absolute POSIX path.

Up to v1.13.5 the signature for the RealPath method was:

RealPath(string) string

we have added a legacyRealPathFileLister that implements the old method to ensure that your code does not break. You should use the new method signature to avoid future issues

type Request 

type Request struct {
	// Get, Put, Setstat, Stat, Rename, Remove
	// Rmdir, Mkdir, List, Readlink, Link, Symlink
	Method   string
	Filepath string
	Flags    uint32
	Attrs    []byte // convert to sub-struct
	Target   string // for renames and sym-links
	// contains filtered or unexported fields
}

Request contains the data and state for the incoming service request.

func NewRequest 

func NewRequest(method, path string) *Request

NewRequest creates a new Request object.

func (*Request) AttrFlags 

func (r *Request) AttrFlags() FileAttrFlags

AttrFlags returns a FileAttrFlags boolean struct based on the bitmap/uint32 file attribute flags from the SFTP packaet.

func (*Request) Attributes 

func (r *Request) Attributes() *FileStat

Attributes parses file attributes byte blob and return them in a FileStat object.

func (*Request) Context 

func (r *Request) Context() context.Context

Context returns the request's context. To change the context, use WithContext.

The returned context is always non-nil; it defaults to the background context.

For incoming server requests, the context is canceled when the request is complete or the client's connection closes.

func (*Request) Pflags 

func (r *Request) Pflags() FileOpenFlags

Pflags converts the bitmap/uint32 from SFTP Open packet pflag values, into a FileOpenFlags struct with booleans set for flags set in bitmap.

func (*Request) WithContext 

func (r *Request) WithContext(ctx context.Context) *Request

WithContext returns a copy of r with its context changed to ctx. The provided ctx must be non-nil.

type RequestServer 

type RequestServer struct {
	Handlers Handlers
	// contains filtered or unexported fields
}

RequestServer abstracts the sftp protocol with an http request-like protocol

func NewRequestServer 

func NewRequestServer(rwc io.ReadWriteCloser, h Handlers, options ...RequestServerOption) *RequestServer

NewRequestServer creates/allocates/returns new RequestServer. Normally there will be one server per user-session.

func (*RequestServer) Close 

func (rs *RequestServer) Close() error

Close the read/write/closer to trigger exiting the main server loop

func (*RequestServer) Serve 

func (rs *RequestServer) Serve() error

Serve requests for user session

type RequestServerOption 

type RequestServerOption func(*RequestServer)

A RequestServerOption is a function which applies configuration to a RequestServer.

func WithRSAllocator 

func WithRSAllocator() RequestServerOption

WithRSAllocator enable the allocator. After processing a packet we keep in memory the allocated slices and we reuse them for new packets. The allocator is experimental

func WithStartDirectory 

func WithStartDirectory(startDirectory string) RequestServerOption

WithStartDirectory sets a start directory to use as base for relative paths. If unset the default is "/"

type Server 

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

Server is an SSH File Transfer Protocol (sftp) server. This is intended to provide the sftp subsystem to an ssh server daemon. This implementation currently supports most of sftp server protocol version 3, as specified at https://filezilla-project.org/specs/draft-ietf-secsh-filexfer-02.txt

func NewServer 

func NewServer(rwc io.ReadWriteCloser, options ...ServerOption) (*Server, error)

NewServer creates a new Server instance around the provided streams, serving content from the root of the filesystem. Optionally, ServerOption functions may be specified to further configure the Server.

A subsequent call to Serve() is required to begin serving files over SFTP.

func (*Server) Serve 

func (svr *Server) Serve() error

Serve serves SFTP connections until the streams stop or the SFTP subsystem is stopped. It returns nil if the server exits cleanly.

type ServerOption 

type ServerOption func(*Server) error

A ServerOption is a function which applies configuration to a Server.

func ReadOnly 

func ReadOnly() ServerOption

ReadOnly configures a Server to serve files in read-only mode.

func WithAllocator 

func WithAllocator() ServerOption

WithAllocator enable the allocator. After processing a packet we keep in memory the allocated slices and we reuse them for new packets. The allocator is experimental

func WithDebug 

func WithDebug(w io.Writer) ServerOption

WithDebug enables Server debugging output to the supplied io.Writer.

func WithServerWorkingDirectory 

func WithServerWorkingDirectory(workDir string) ServerOption

WithServerWorkingDirectory sets a working directory to use as base for relative paths. If unset the default is current working directory (os.Getwd).

type StatExtended 

type StatExtended struct {
	ExtType string
	ExtData string
}

StatExtended contains additional, extended information for a FileStat.

type StatVFS 

type StatVFS struct {
	ID      uint32
	Bsize   uint64 /* file system block size */
	Frsize  uint64 /* fundamental fs block size */
	Blocks  uint64 /* number of blocks (unit f_frsize) */
	Bfree   uint64 /* free blocks in file system */
	Bavail  uint64 /* free blocks for non-root */
	Files   uint64 /* total file inodes */
	Ffree   uint64 /* free file inodes */
	Favail  uint64 /* free file inodes for to non-root */
	Fsid    uint64 /* file system id */
	Flag    uint64 /* bit mask of f_flag values */
	Namemax uint64 /* maximum filename length */
}

A StatVFS contains statistics about a filesystem.

func (*StatVFS) FreeSpace 

func (p *StatVFS) FreeSpace() uint64

FreeSpace calculates the amount of free space in a filesystem.

func (*StatVFS) MarshalBinary 

func (p *StatVFS) MarshalBinary() ([]byte, error)

MarshalBinary encodes the StatVFS as an SSH_FXP_EXTENDED_REPLY packet.

func (*StatVFS) TotalSpace 

func (p *StatVFS) TotalSpace() uint64

TotalSpace calculates the amount of total space in a filesystem.

type StatVFSFileCmder 

type StatVFSFileCmder interface {
	FileCmder
	StatVFS(*Request) (*StatVFS, error)
}

StatVFSFileCmder is a FileCmder that implements the StatVFS method. You need to implement this interface if you want to handle statvfs requests. Please also be sure that the statvfs@openssh.com extension is enabled

type StatusError 

type StatusError struct {
	Code uint32
	// contains filtered or unexported fields
}

A StatusError is returned when an SFTP operation fails, and provides additional information about the failure.

func (*StatusError) Error 

func (s *StatusError) Error() string

func (*StatusError) FxCode 

func (s *StatusError) FxCode() fxerr

FxCode returns the error code typed to match against the exported codes

type TransferError 

type TransferError interface {
	TransferError(err error)
}

TransferError is an optional interface that readerAt and writerAt can implement to be notified about the error causing Serve() to exit with the request still open

type WriterAtReaderAt 

type WriterAtReaderAt interface {
	io.WriterAt
	io.ReaderAt
}

WriterAtReaderAt defines the interface to return when a file is to be opened for reading and writing

Source Files

View all Source files

Directories

Path Synopsis
examples
buffered-read-benchmark
buffered-read-benchmark benchmarks the peformance of reading from /dev/zero on the server to a []byte on the client via io.Copy.
 buffered-read-benchmark benchmarks the peformance of reading from /dev/zero on the server to a []byte on the client via io.Copy.
buffered-write-benchmark
buffered-write-benchmark benchmarks the peformance of writing a single large []byte on the client to /dev/null on the server via io.Copy.
 buffered-write-benchmark benchmarks the peformance of writing a single large []byte on the client to /dev/null on the server via io.Copy.
go-sftp-server
An example SFTP server implementation using the golang SSH package.
 An example SFTP server implementation using the golang SSH package.
request-server
An example SFTP server implementation using the golang SSH package.
 An example SFTP server implementation using the golang SSH package.
streaming-read-benchmark
streaming-read-benchmark benchmarks the peformance of reading from /dev/zero on the server to /dev/null on the client via io.Copy.
 streaming-read-benchmark benchmarks the peformance of reading from /dev/zero on the server to /dev/null on the client via io.Copy.
streaming-write-benchmark
streaming-write-benchmark benchmarks the peformance of writing from /dev/zero on the client to /dev/null on the server via io.Copy.
 streaming-write-benchmark benchmarks the peformance of writing from /dev/zero on the client to /dev/null on the server via io.Copy.
internal
encoding/ssh/filexfer
Package sshfx implements the wire encoding for secsh-filexfer as described in https://filezilla-project.org/specs/draft-ietf-secsh-filexfer-02.txt
 Package sshfx implements the wire encoding for secsh-filexfer as described in https://filezilla-project.org/specs/draft-ietf-secsh-filexfer-02.txt
encoding/ssh/filexfer/openssh
Package openssh implements the openssh secsh-filexfer extensions as described in https://github.com/openssh/openssh-portable/blob/master/PROTOCOL
 Package openssh implements the openssh secsh-filexfer extensions as described in https://github.com/openssh/openssh-portable/blob/master/PROTOCOL

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