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restic/cmd/restic/exclude.go
2020-09-21 19:20:24 +08:00

347 lines
8.7 KiB
Go

package main
import (
"bytes"
"fmt"
"io"
"os"
"path/filepath"
"strconv"
"strings"
"sync"
"github.com/restic/restic/internal/debug"
"github.com/restic/restic/internal/errors"
"github.com/restic/restic/internal/filter"
"github.com/restic/restic/internal/fs"
"github.com/restic/restic/internal/repository"
)
type rejectionCache struct {
m map[string]bool
mtx sync.Mutex
}
// Lock locks the mutex in rc.
func (rc *rejectionCache) Lock() {
if rc != nil {
rc.mtx.Lock()
}
}
// Unlock unlocks the mutex in rc.
func (rc *rejectionCache) Unlock() {
if rc != nil {
rc.mtx.Unlock()
}
}
// Get returns the last stored value for dir and a second boolean that
// indicates whether that value was actually written to the cache. It is the
// callers responsibility to call rc.Lock and rc.Unlock before using this
// method, otherwise data races may occur.
func (rc *rejectionCache) Get(dir string) (bool, bool) {
if rc == nil || rc.m == nil {
return false, false
}
v, ok := rc.m[dir]
return v, ok
}
// Store stores a new value for dir. It is the callers responsibility to call
// rc.Lock and rc.Unlock before using this method, otherwise data races may
// occur.
func (rc *rejectionCache) Store(dir string, rejected bool) {
if rc == nil {
return
}
if rc.m == nil {
rc.m = make(map[string]bool)
}
rc.m[dir] = rejected
}
// RejectByNameFunc is a function that takes a filename of a
// file that would be included in the backup. The function returns true if it
// should be excluded (rejected) from the backup.
type RejectByNameFunc func(path string) bool
// RejectFunc is a function that takes a filename and os.FileInfo of a
// file that would be included in the backup. The function returns true if it
// should be excluded (rejected) from the backup.
type RejectFunc func(path string, fi os.FileInfo) bool
// rejectByPattern returns a RejectByNameFunc which rejects files that match
// one of the patterns.
func rejectByPattern(patterns []string) RejectByNameFunc {
return func(item string) bool {
matched, _, err := filter.List(patterns, item)
if err != nil {
Warnf("error for exclude pattern: %v", err)
}
if matched {
debug.Log("path %q excluded by an exclude pattern", item)
return true
}
return false
}
}
// Same as `rejectByPattern` but case insensitive.
func rejectByInsensitivePattern(patterns []string) RejectByNameFunc {
for index, path := range patterns {
patterns[index] = strings.ToLower(path)
}
rejFunc := rejectByPattern(patterns)
return func(item string) bool {
return rejFunc(strings.ToLower(item))
}
}
// rejectIfPresent returns a RejectByNameFunc which itself returns whether a path
// should be excluded. The RejectByNameFunc considers a file to be excluded when
// it resides in a directory with an exclusion file, that is specified by
// excludeFileSpec in the form "filename[:content]". The returned error is
// non-nil if the filename component of excludeFileSpec is empty. If rc is
// non-nil, it is going to be used in the RejectByNameFunc to expedite the evaluation
// of a directory based on previous visits.
func rejectIfPresent(excludeFileSpec string) (RejectByNameFunc, error) {
if excludeFileSpec == "" {
return nil, errors.New("name for exclusion tagfile is empty")
}
colon := strings.Index(excludeFileSpec, ":")
if colon == 0 {
return nil, fmt.Errorf("no name for exclusion tagfile provided")
}
tf, tc := "", ""
if colon > 0 {
tf = excludeFileSpec[:colon]
tc = excludeFileSpec[colon+1:]
} else {
tf = excludeFileSpec
}
debug.Log("using %q as exclusion tagfile", tf)
rc := &rejectionCache{}
fn := func(filename string) bool {
return isExcludedByFile(filename, tf, tc, rc)
}
return fn, nil
}
// isExcludedByFile interprets filename as a path and returns true if that file
// is in an excluded directory. A directory is identified as excluded if it contains a
// tagfile which bears the name specified in tagFilename and starts with
// header. If rc is non-nil, it is used to expedite the evaluation of a
// directory based on previous visits.
func isExcludedByFile(filename, tagFilename, header string, rc *rejectionCache) bool {
if tagFilename == "" {
return false
}
dir, base := filepath.Split(filename)
if base == tagFilename {
return false // do not exclude the tagfile itself
}
rc.Lock()
defer rc.Unlock()
rejected, visited := rc.Get(dir)
if visited {
return rejected
}
rejected = isDirExcludedByFile(dir, tagFilename, header)
rc.Store(dir, rejected)
return rejected
}
func isDirExcludedByFile(dir, tagFilename, header string) bool {
tf := filepath.Join(dir, tagFilename)
_, err := fs.Lstat(tf)
if os.IsNotExist(err) {
return false
}
if err != nil {
Warnf("could not access exclusion tagfile: %v", err)
return false
}
// when no signature is given, the mere presence of tf is enough reason
// to exclude filename
if len(header) == 0 {
return true
}
// From this stage, errors mean tagFilename exists but it is malformed.
// Warnings will be generated so that the user is informed that the
// indented ignore-action is not performed.
f, err := os.Open(tf)
if err != nil {
Warnf("could not open exclusion tagfile: %v", err)
return false
}
defer f.Close()
buf := make([]byte, len(header))
_, err = io.ReadFull(f, buf)
// EOF is handled with a dedicated message, otherwise the warning were too cryptic
if err == io.EOF {
Warnf("invalid (too short) signature in exclusion tagfile %q\n", tf)
return false
}
if err != nil {
Warnf("could not read signature from exclusion tagfile %q: %v\n", tf, err)
return false
}
if !bytes.Equal(buf, []byte(header)) {
Warnf("invalid signature in exclusion tagfile %q\n", tf)
return false
}
return true
}
// gatherDevices returns the set of unique device ids of the files and/or
// directory paths listed in "items".
func gatherDevices(items []string) (deviceMap map[string]uint64, err error) {
deviceMap = make(map[string]uint64)
for _, item := range items {
item, err = filepath.Abs(filepath.Clean(item))
if err != nil {
return nil, err
}
fi, err := fs.Lstat(item)
if err != nil {
return nil, err
}
id, err := fs.DeviceID(fi)
if err != nil {
return nil, err
}
deviceMap[item] = id
}
if len(deviceMap) == 0 {
return nil, errors.New("zero allowed devices")
}
return deviceMap, nil
}
// rejectByDevice returns a RejectFunc that rejects files which are on a
// different file systems than the files/dirs in samples.
func rejectByDevice(samples []string) (RejectFunc, error) {
allowed, err := gatherDevices(samples)
if err != nil {
return nil, err
}
debug.Log("allowed devices: %v\n", allowed)
return func(item string, fi os.FileInfo) bool {
if fi == nil {
return false
}
item = filepath.Clean(item)
id, err := fs.DeviceID(fi)
if err != nil {
// This should never happen because gatherDevices() would have
// errored out earlier. If it still does that's a reason to panic.
panic(err)
}
for dir := item; ; dir = filepath.Dir(dir) {
debug.Log("item %v, test dir %v", item, dir)
allowedID, ok := allowed[dir]
if !ok {
if dir == filepath.Dir(dir) {
break
}
continue
}
if allowedID != id {
debug.Log("path %q on disallowed device %d", item, id)
return true
}
return false
}
panic(fmt.Sprintf("item %v, device id %v not found, allowedDevs: %v", item, id, allowed))
}, nil
}
// rejectResticCache returns a RejectByNameFunc that rejects the restic cache
// directory (if set).
func rejectResticCache(repo *repository.Repository) (RejectByNameFunc, error) {
if repo.Cache == nil {
return func(string) bool {
return false
}, nil
}
cacheBase := repo.Cache.BaseDir()
if cacheBase == "" {
return nil, errors.New("cacheBase is empty string")
}
return func(item string) bool {
if fs.HasPathPrefix(cacheBase, item) {
debug.Log("rejecting restic cache directory %v", item)
return true
}
return false
}, nil
}
func rejectBySize(maxSizeStr string) (RejectFunc, error) {
maxSize, err := parseSizeStr(maxSizeStr)
if err != nil {
return nil, err
}
return func(item string, fi os.FileInfo) bool {
if fi == nil {
return false
}
// directory will be ignored
if fi.IsDir() {
return false
}
filesize := fi.Size()
if filesize > maxSize {
debug.Log("file %s is oversize: %d", item, filesize)
return true
}
return false
}, nil
}
func parseSizeStr(sizeStr string) (int64, error) {
numStr := sizeStr[:len(sizeStr)-1]
var unit int64 = 1
switch sizeStr[len(sizeStr)-1] {
case 'b', 'B':
// use initialized values, do nothing here
case 'k', 'K':
unit = 1024
case 'm', 'M':
unit = 1024 * 1024
case 'g', 'G':
unit = 1024 * 1024 * 1024
case 't', 'T':
unit = 1024 * 1024 * 1024 * 1024
default:
numStr = sizeStr
}
value, err := strconv.ParseInt(numStr, 10, 64)
if err != nil {
return 0, nil
}
return value * unit, nil
}