package mtree import ( "fmt" "os" "strconv" "strings" "time" "github.com/Sirupsen/logrus" "github.com/vbatts/go-mtree/pkg/govis" ) // UpdateKeywordFunc is the signature for a function that will restore a file's // attributes. Where path is relative path to the file, and value to be // restored to. type UpdateKeywordFunc func(path string, kv KeyVal) (os.FileInfo, error) // UpdateKeywordFuncs is the registered list of functions to update file attributes. // Keyed by the keyword as it would show up in the manifest var UpdateKeywordFuncs = map[Keyword]UpdateKeywordFunc{ "mode": modeUpdateKeywordFunc, "time": timeUpdateKeywordFunc, "tar_time": tartimeUpdateKeywordFunc, "uid": uidUpdateKeywordFunc, "gid": gidUpdateKeywordFunc, "xattr": xattrUpdateKeywordFunc, "link": linkUpdateKeywordFunc, } func uidUpdateKeywordFunc(path string, kv KeyVal) (os.FileInfo, error) { uid, err := strconv.Atoi(kv.Value()) if err != nil { return nil, err } stat, err := os.Lstat(path) if err != nil { return nil, err } if statIsUID(stat, uid) { return stat, nil } if err := os.Lchown(path, uid, -1); err != nil { return nil, err } return os.Lstat(path) } func gidUpdateKeywordFunc(path string, kv KeyVal) (os.FileInfo, error) { gid, err := strconv.Atoi(kv.Value()) if err != nil { return nil, err } stat, err := os.Lstat(path) if err != nil { return nil, err } if statIsGID(stat, gid) { return stat, nil } if err := os.Lchown(path, -1, gid); err != nil { return nil, err } return os.Lstat(path) } func modeUpdateKeywordFunc(path string, kv KeyVal) (os.FileInfo, error) { info, err := os.Lstat(path) if err != nil { return nil, err } // don't set mode on symlinks, as it passes through to the backing file if info.Mode()&os.ModeSymlink != 0 { return info, nil } vmode, err := strconv.ParseInt(kv.Value(), 8, 32) if err != nil { return nil, err } stat, err := os.Lstat(path) if err != nil { return nil, err } if stat.Mode() == os.FileMode(vmode) { return stat, nil } logrus.Debugf("path: %q, kv.Value(): %q, vmode: %o", path, kv.Value(), vmode) if err := os.Chmod(path, os.FileMode(vmode)); err != nil { return nil, err } return os.Lstat(path) } // since tar_time will only be second level precision, then when restoring the // filepath from a tar_time, then compare the seconds first and only Chtimes if // the seconds value is different. func tartimeUpdateKeywordFunc(path string, kv KeyVal) (os.FileInfo, error) { info, err := os.Lstat(path) if err != nil { return nil, err } v := strings.SplitN(kv.Value(), ".", 2) if len(v) != 2 { return nil, fmt.Errorf("expected a number like 1469104727.000000000") } sec, err := strconv.ParseInt(v[0], 10, 64) if err != nil { return nil, fmt.Errorf("expected seconds, but got %q", v[0]) } // if the seconds are the same, don't do anything, because the file might // have nanosecond value, and if using tar_time it would zero it out. if info.ModTime().Unix() == sec { return info, nil } vtime := time.Unix(sec, 0) // if times are same then don't modify anything // comparing Unix, since it does not include Nano seconds if info.ModTime().Unix() == vtime.Unix() { return info, nil } // symlinks are strange and most of the time passes through to the backing file if info.Mode()&os.ModeSymlink != 0 { if err := lchtimes(path, vtime, vtime); err != nil { return nil, err } } else if err := os.Chtimes(path, vtime, vtime); err != nil { return nil, err } return os.Lstat(path) } // this is nano second precision func timeUpdateKeywordFunc(path string, kv KeyVal) (os.FileInfo, error) { info, err := os.Lstat(path) if err != nil { return nil, err } v := strings.SplitN(kv.Value(), ".", 2) if len(v) != 2 { return nil, fmt.Errorf("expected a number like 1469104727.871937272") } nsec, err := strconv.ParseInt(v[0]+v[1], 10, 64) if err != nil { return nil, fmt.Errorf("expected nano seconds, but got %q", v[0]+v[1]) } logrus.Debugf("arg: %q; nsec: %d", v[0]+v[1], nsec) vtime := time.Unix(0, nsec) // if times are same then don't modify anything if info.ModTime().Equal(vtime) { return info, nil } // symlinks are strange and most of the time passes through to the backing file if info.Mode()&os.ModeSymlink != 0 { if err := lchtimes(path, vtime, vtime); err != nil { return nil, err } } else if err := os.Chtimes(path, vtime, vtime); err != nil { return nil, err } return os.Lstat(path) } func linkUpdateKeywordFunc(path string, kv KeyVal) (os.FileInfo, error) { linkname, err := govis.Unvis(kv.Value(), DefaultVisFlags) if err != nil { return nil, err } got, err := os.Readlink(path) if err != nil { return nil, err } if got == linkname { return os.Lstat(path) } logrus.Debugf("linkUpdateKeywordFunc: removing %q to link to %q", path, linkname) if err := os.Remove(path); err != nil { return nil, err } if err := os.Symlink(linkname, path); err != nil { return nil, err } return os.Lstat(path) }