rclone/cmd/mountlib/utils.go
Ivan Andreev 8c10dee510 mountlib: use procfs to validate mount on linux - #5593
Current way of checking whether mountpoint has been already mounted (directory
list) can result in race if rclone runs under Automount (classic or systemd).

This patch adopts Linux ProcFS for the check. Note that mountpoint is considered
empty if it's tagged as "mounted" by autofs. Also ProcFS is used to check whether
rclone mount was successful (ie. tagged by a string containing "rclone").

On macOS/BSD where ProcFS is unavailable the old method is still used.

This patch also moves a few utility functions unchanged to utils.go:
CheckOverlap, CheckAllowings, SetVolumeName.
2021-10-02 23:45:16 +03:00

105 lines
2.5 KiB
Go

package mountlib
import (
"path/filepath"
"runtime"
"strings"
"github.com/pkg/errors"
"github.com/rclone/rclone/fs"
)
// ClipBlocks clips the blocks pointed to the OS max
func ClipBlocks(b *uint64) {
var max uint64
switch runtime.GOOS {
case "windows":
if runtime.GOARCH == "386" {
max = (1 << 32) - 1
} else {
max = (1 << 43) - 1
}
case "darwin":
// OSX FUSE only supports 32 bit number of blocks
// https://github.com/osxfuse/osxfuse/issues/396
max = (1 << 32) - 1
default:
// no clipping
return
}
if *b > max {
*b = max
}
}
// CheckOverlap checks that root doesn't overlap with mountpoint
func (m *MountPoint) CheckOverlap() error {
name := m.Fs.Name()
if name != "" && name != "local" {
return nil
}
rootAbs := absPath(m.Fs.Root())
mountpointAbs := absPath(m.MountPoint)
if strings.HasPrefix(rootAbs, mountpointAbs) || strings.HasPrefix(mountpointAbs, rootAbs) {
const msg = "mount point %q and directory to be mounted %q mustn't overlap"
return errors.Errorf(msg, m.MountPoint, m.Fs.Root())
}
return nil
}
// absPath is a helper function for MountPoint.CheckOverlap
func absPath(path string) string {
if abs, err := filepath.EvalSymlinks(path); err == nil {
path = abs
}
if abs, err := filepath.Abs(path); err == nil {
path = abs
}
path = filepath.ToSlash(path)
if !strings.HasSuffix(path, "/") {
path += "/"
}
return path
}
// CheckAllowings informs about ignored flags on Windows. If not on Windows
// and not --allow-non-empty flag is used, verify that mountpoint is empty.
func (m *MountPoint) CheckAllowings() error {
opt := &m.MountOpt
if runtime.GOOS == "windows" {
if opt.AllowNonEmpty {
fs.Logf(nil, "--allow-non-empty flag does nothing on Windows")
}
if opt.AllowRoot {
fs.Logf(nil, "--allow-root flag does nothing on Windows")
}
if opt.AllowOther {
fs.Logf(nil, "--allow-other flag does nothing on Windows")
}
return nil
}
if !opt.AllowNonEmpty {
return CheckMountEmpty(m.MountPoint)
}
return nil
}
// SetVolumeName with sensible default
func (m *MountPoint) SetVolumeName(vol string) {
if vol == "" {
vol = m.Fs.Name() + ":" + m.Fs.Root()
}
m.MountOpt.SetVolumeName(vol)
}
// SetVolumeName removes special characters from volume name if necessary
func (o *Options) SetVolumeName(vol string) {
vol = strings.ReplaceAll(vol, ":", " ")
vol = strings.ReplaceAll(vol, "/", " ")
vol = strings.TrimSpace(vol)
if runtime.GOOS == "windows" && len(vol) > 32 {
vol = vol[:32]
}
o.VolumeName = vol
}