rclone/backend/local/metadata_linux.go

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//go:build linux
// +build linux
package local
import (
"fmt"
"sync"
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"time"
"github.com/rclone/rclone/fs"
"golang.org/x/sys/unix"
)
var (
statxCheckOnce sync.Once
readMetadataFromFileFn func(o *Object, m *fs.Metadata) (err error)
)
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// Read the metadata from the file into metadata where possible
func (o *Object) readMetadataFromFile(m *fs.Metadata) (err error) {
statxCheckOnce.Do(func() {
// Check statx() is available as it was only introduced in kernel 4.11
// If not, fall back to fstatat() which was introduced in 2.6.16 which is guaranteed for all Go versions
var stat unix.Statx_t
if unix.Statx(unix.AT_FDCWD, ".", 0, unix.STATX_ALL, &stat) != unix.ENOSYS {
readMetadataFromFileFn = readMetadataFromFileStatx
} else {
readMetadataFromFileFn = readMetadataFromFileFstatat
}
})
return readMetadataFromFileFn(o, m)
}
// Read the metadata from the file into metadata where possible
func readMetadataFromFileStatx(o *Object, m *fs.Metadata) (err error) {
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flags := unix.AT_SYMLINK_NOFOLLOW
if o.fs.opt.FollowSymlinks {
flags = 0
}
var stat unix.Statx_t
// statx() was added to Linux in kernel 4.11
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err = unix.Statx(unix.AT_FDCWD, o.path, flags, (0 |
unix.STATX_TYPE | // Want stx_mode & S_IFMT
unix.STATX_MODE | // Want stx_mode & ~S_IFMT
unix.STATX_UID | // Want stx_uid
unix.STATX_GID | // Want stx_gid
unix.STATX_ATIME | // Want stx_atime
unix.STATX_MTIME | // Want stx_mtime
unix.STATX_CTIME | // Want stx_ctime
unix.STATX_BTIME), // Want stx_btime
&stat)
if err != nil {
return err
}
m.Set("mode", fmt.Sprintf("%0o", stat.Mode))
m.Set("uid", fmt.Sprintf("%d", stat.Uid))
m.Set("gid", fmt.Sprintf("%d", stat.Gid))
if stat.Rdev_major != 0 || stat.Rdev_minor != 0 {
m.Set("rdev", fmt.Sprintf("%x", uint64(stat.Rdev_major)<<32|uint64(stat.Rdev_minor)))
}
setTime := func(key string, t unix.StatxTimestamp) {
m.Set(key, time.Unix(t.Sec, int64(t.Nsec)).Format(metadataTimeFormat))
}
setTime("atime", stat.Atime)
setTime("mtime", stat.Mtime)
setTime("btime", stat.Btime)
return nil
}
// Read the metadata from the file into metadata where possible
func readMetadataFromFileFstatat(o *Object, m *fs.Metadata) (err error) {
flags := unix.AT_SYMLINK_NOFOLLOW
if o.fs.opt.FollowSymlinks {
flags = 0
}
var stat unix.Stat_t
// fstatat() was added to Linux in kernel 2.6.16
// Go only supports 2.6.32 or later
err = unix.Fstatat(unix.AT_FDCWD, o.path, &stat, flags)
if err != nil {
return err
}
m.Set("mode", fmt.Sprintf("%0o", stat.Mode))
m.Set("uid", fmt.Sprintf("%d", stat.Uid))
m.Set("gid", fmt.Sprintf("%d", stat.Gid))
if stat.Rdev != 0 {
m.Set("rdev", fmt.Sprintf("%x", stat.Rdev))
}
setTime := func(key string, t unix.Timespec) {
// The types of t.Sec and t.Nsec vary from int32 to int64 on
// different Linux architectures so we need to cast them to
// int64 here and hence need to quiet the linter about
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// unnecessary casts.
//
// nolint: unconvert
m.Set(key, time.Unix(int64(t.Sec), int64(t.Nsec)).Format(metadataTimeFormat))
}
setTime("atime", stat.Atim)
setTime("mtime", stat.Mtim)
return nil
}