/
files.go
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/
files.go
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// Copyright 2015 Keybase, Inc. All rights reserved. Use of
// this source code is governed by the included BSD license.
package client
import (
"bufio"
"bytes"
"errors"
"fmt"
"io"
"os"
"github.com/keybase/client/go/libkb"
"github.com/keybase/client/go/terminalescaper"
isatty "github.com/mattn/go-isatty"
keybase1 "github.com/keybase/client/go/protocol/keybase1"
)
type Source interface {
io.ReadCloser
io.Seeker
Open() error
CloseWithError(error) error
}
type Sink interface {
io.WriteCloser
Open() error
HitError(err error) error
}
type BufferSource struct {
data string
buf *bytes.Buffer
}
func NewBufferSource(s string) *BufferSource {
return &BufferSource{data: s}
}
func (b *BufferSource) Open() error {
b.buf = bytes.NewBufferString(b.data)
return nil
}
func (b *BufferSource) Read(p []byte) (n int, err error) {
return b.buf.Read(p)
}
func (b *BufferSource) Close() error { return nil }
func (b *BufferSource) CloseWithError(error) error { return nil }
func (b *BufferSource) Seek(offset int64, whence int) (int64, error) {
return 0, errors.New("BufferSource does not support Seek")
}
type StdinSource struct {
open bool
}
func (b *StdinSource) Open() error {
b.open = true
return nil
}
func drain(f *os.File) error {
buf := make([]byte, 1024*64)
var err error
var n int
eof := false
for !eof && err == nil {
if n, err = f.Read(buf); n == 0 && err != nil {
eof = true
if err == io.EOF {
err = nil
}
}
}
return err
}
// Close a source, but consume all leftover input before so doing.
func (b *StdinSource) Close() error {
var err error
if b.open {
err = drain(os.Stdin)
}
b.open = false
return err
}
func (b *StdinSource) CloseWithError(e error) error {
if e != nil {
b.open = false
return nil
}
return b.Close()
}
func (b *StdinSource) Read(p []byte) (n int, err error) {
if b.open {
n, err := os.Stdin.Read(p)
if n == 0 {
b.open = false
}
return n, err
}
return 0, io.EOF
}
func (b *StdinSource) Seek(offset int64, whence int) (int64, error) {
return 0, errors.New("StdinSource does not support Seek")
}
// isValidFile verifies the file in question is not actually a directory.
func isValidFile(file *os.File) error {
finfo, err := file.Stat()
if err != nil {
return err
}
if mode := finfo.Mode(); mode.IsDir() {
return fmt.Errorf("A directory is not a valid file")
}
return nil
}
type FileSource struct {
name string
file *os.File
}
func NewFileSource(s string) *FileSource {
return &FileSource{name: s}
}
func (s *FileSource) Open() error {
f, err := os.OpenFile(s.name, os.O_RDONLY, 0)
if err != nil {
return err
}
if err = isValidFile(f); err != nil {
return err
}
s.file = f
return nil
}
func (s *FileSource) Close() error {
if s.file == nil {
return nil
}
err := s.file.Close()
s.file = nil
return err
}
func (s *FileSource) CloseWithError(e error) error {
return s.Close()
}
func (s *FileSource) Read(p []byte) (n int, err error) {
if s.file == nil {
return 0, io.EOF
}
if n, err = s.file.Read(p); n == 0 || err != nil {
// not sure why we Close() here instead of letting
// caller Close() when they want...
s.file.Close()
s.file = nil
}
return n, err
}
// Seek implements io.Seeker.
//
// Some notes:
//
// s.file could be nil because FileSource.Read() closes s.file at
// the end of reading a file. If s.file is nil, Seek will reopen
// the file.
//
// The alternative is to remove the Close() in Read(),
// but leave that untouched so as not to break
// anything that depends on that behavior.
func (s *FileSource) Seek(offset int64, whence int) (int64, error) {
if s.file == nil {
// the file could be nil because Read(...) closes
// at the end of reading. Reopen it here:
if err := s.Open(); err != nil {
return 0, err
}
}
return s.file.Seek(offset, whence)
}
type StdoutSink struct {
open bool
}
func (s *StdoutSink) Open() error {
s.open = true
return nil
}
func (s *StdoutSink) Close() error {
s.open = false
return nil
}
func (s *StdoutSink) Write(b []byte) (n int, err error) {
return os.Stdout.Write(b)
}
func (s *StdoutSink) HitError(e error) error { return nil }
// EscapedSink can be used to write data to the underlying Sink, while transparently sanitizing it.
// If an error occurs writing to an EscapedSink, no more data will be
// accepted and all subsequent writes will return the error.
type EscapedSink struct {
err error
Sink
}
// Write writes p to the underlying Sink, after sanitizing it.
// It returns n = len(p) on a successful write (regardless of how much data is written to the underlying Sink).
// This is because the escaping function might alter the actual dimension of the data, but the caller is interested
// in knowing how much of what they wanted to write was actually written. In case of errors it (conservatively) returns n=0
// and the error, and no other writes are possible.
func (s *EscapedSink) Write(p []byte) (int, error) {
if s.err != nil {
return 0, s.err
}
_, err := s.Sink.Write(terminalescaper.CleanBytes(p))
if err == nil {
return len(p), nil
}
s.err = err
return 0, err
}
type FileSink struct {
libkb.Contextified
name string
file *os.File
bufw *bufio.Writer
opened bool
closed bool
failed bool
}
func NewFileSink(g *libkb.GlobalContext, s string) *FileSink {
return &FileSink{Contextified: libkb.NewContextified(g), name: s}
}
func (s *FileSink) Open() error {
// Lazy-open on first write
return nil
}
func (s *FileSink) lazyOpen() error {
var err error
if s.closed {
err = fmt.Errorf("file was already closed")
} else if s.failed {
err = fmt.Errorf("open previously failed")
} else if !s.opened {
flags := os.O_WRONLY | os.O_CREATE | os.O_TRUNC
mode := libkb.UmaskablePermFile
f, err := os.OpenFile(s.name, flags, mode)
if err != nil {
s.failed = true
return fmt.Errorf("Failed to open %s for writing: %s",
s.name, err)
}
if err := isValidFile(f); err != nil {
s.failed = true
return err
}
s.file = f
s.bufw = bufio.NewWriter(f)
s.opened = true
}
return err
}
func (s *FileSink) Write(b []byte) (n int, err error) {
if err = s.lazyOpen(); err != nil {
return
}
return s.bufw.Write(b)
}
func (s *FileSink) Close() error {
var err error
if s.opened && !s.closed {
s.bufw.Flush()
err = s.file.Close()
s.file = nil
s.bufw = nil
s.closed = true
}
return err
}
func (s *FileSink) HitError(e error) error {
var err error
if e != nil && s.opened {
s.G().Log.Debug("Deleting file %s after error %s", s.name, e)
err = os.Remove(s.name)
}
return err
}
type UnixFilter struct {
libkb.Contextified
sink Sink
source Source
msg string // input
infile string
outfile string
}
func initSink(g *libkb.GlobalContext, fn string) Sink {
if len(fn) == 0 || fn == "-" {
if g.Env.GetDisplayRawUntrustedOutput() || !isatty.IsTerminal(os.Stdout.Fd()) {
return &StdoutSink{}
}
return &EscapedSink{Sink: &StdoutSink{}}
}
return NewFileSink(g, fn)
}
var ErrDuplicateSource = errors.New("Can't handle both a passed message and an infile")
func initSource(msg, infile string) (Source, error) {
if len(msg) > 0 && len(infile) > 0 {
return nil, ErrDuplicateSource
}
if len(msg) > 0 {
return NewBufferSource(msg), nil
}
if len(infile) == 0 || infile == "-" {
return &StdinSource{}, nil
}
return NewFileSource(infile), nil
}
func (u *UnixFilter) FilterInit(g *libkb.GlobalContext, msg, infile, outfile string) (err error) {
if len(msg) > 0 && len(infile) > 0 {
return ErrDuplicateSource
}
u.msg = msg
u.infile = infile
u.outfile = outfile
return nil
}
func (u *UnixFilter) FilterOpen(g *libkb.GlobalContext) (err error) {
if u.source, err = initSource(u.msg, u.infile); err != nil {
return err
}
u.sink = initSink(g, u.outfile)
if err = u.sink.Open(); err != nil {
return err
}
if err = u.source.Open(); err != nil {
return err
}
return nil
}
func (u *UnixFilter) Close(inerr error) error {
var e1, e2, e3 error
if u.source != nil {
e1 = u.source.CloseWithError(inerr)
}
if u.sink != nil {
e2 = u.sink.Close()
e3 = u.sink.HitError(inerr)
}
return libkb.PickFirstError(e1, e2, e3)
}
func (u *UnixFilter) ClientFilterOpen(g *libkb.GlobalContext) (snk, src keybase1.Stream, err error) {
if err = u.FilterOpen(g); err != nil {
return
}
snk = g.XStreams.ExportWriter(u.sink)
src = g.XStreams.ExportReader(u.source)
return
}