Updates moby/sys mountinfo package to v0.6.0

Update to moby/sys/mountinfo package that contains MountedFast
function. The function uses OpenAt2 call for newer kernels
to determine if a mount-point is present or not.

vendor/github.com/moby/sys/mountinfo/go.mod

@@ -1,5 +1,5 @@
 module github.com/moby/sys/mountinfo
 
-go 1.14
+go 1.16
 
-require golang.org/x/sys v0.0.0-20200909081042-eff7692f9009
+require golang.org/x/sys v0.0.0-20211025201205-69cdffdb9359

vendor/github.com/moby/sys/mountinfo/go.sum

@@ -1,2 +1,2 @@
-golang.org/x/sys v0.0.0-20200909081042-eff7692f9009 h1:W0lCpv29Hv0UaM1LXb9QlBHLNP8UFfcKjblhVCWftOM=
-golang.org/x/sys v0.0.0-20200909081042-eff7692f9009/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20211025201205-69cdffdb9359 h1:2B5p2L5IfGiD7+b9BOoRMC6DgObAVZV+Fsp050NqXik=
+golang.org/x/sys v0.0.0-20211025201205-69cdffdb9359/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=

vendor/github.com/moby/sys/mountinfo/mounted_linux.go

@@ -7,6 +7,34 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+// MountedFast is a method of detecting a mount point without reading
+// mountinfo from procfs. A caller can only trust the result if no error
+// and sure == true are returned. Otherwise, other methods (e.g. parsing
+// /proc/mounts) have to be used. If unsure, use Mounted instead (which
+// uses MountedFast, but falls back to parsing mountinfo if needed).
+//
+// If a non-existent path is specified, an appropriate error is returned.
+// In case the caller is not interested in this particular error, it should
+// be handled separately using e.g. errors.Is(err, os.ErrNotExist).
+//
+// This function is only available on Linux. When available (since kernel
+// v5.6), openat2(2) syscall is used to reliably detect all mounts. Otherwise,
+// the implementation falls back to using stat(2), which can reliably detect
+// normal (but not bind) mounts.
+func MountedFast(path string) (mounted, sure bool, err error) {
+	// Root is always mounted.
+	if path == string(os.PathSeparator) {
+		return true, true, nil
+	}
+
+	path, err = normalizePath(path)
+	if err != nil {
+		return false, false, err
+	}
+	mounted, sure, err = mountedFast(path)
+	return
+}
+
 // mountedByOpenat2 is a method of detecting a mount that works for all kinds
 // of mounts (incl. bind mounts), but requires a recent (v5.6+) linux kernel.
 func mountedByOpenat2(path string) (bool, error) {
@@ -16,9 +44,6 @@ func mountedByOpenat2(path string) (bool, error) {
 		Flags: unix.O_PATH | unix.O_CLOEXEC,
 	})
 	if err != nil {
-		if err == unix.ENOENT { // not a mount
-			return false, nil
-		}
 		return false, &os.PathError{Op: "openat2", Path: dir, Err: err}
 	}
 	fd, err := unix.Openat2(dirfd, last, &unix.OpenHow{
@@ -26,33 +51,51 @@ func mountedByOpenat2(path string) (bool, error) {
 		Resolve: unix.RESOLVE_NO_XDEV,
 	})
 	_ = unix.Close(dirfd)
-	switch err {
+	switch err { //nolint:errorlint // unix errors are bare
 	case nil: // definitely not a mount
 		_ = unix.Close(fd)
 		return false, nil
 	case unix.EXDEV: // definitely a mount
 		return true, nil
-	case unix.ENOENT: // not a mount
-		return false, nil
 	}
 	// not sure
 	return false, &os.PathError{Op: "openat2", Path: path, Err: err}
 }
 
-func mounted(path string) (bool, error) {
-	// Try a fast path, using openat2() with RESOLVE_NO_XDEV.
-	mounted, err := mountedByOpenat2(path)
-	if err == nil {
-		return mounted, nil
+// mountedFast is similar to MountedFast, except it expects a normalized path.
+func mountedFast(path string) (mounted, sure bool, err error) {
+	// Root is always mounted.
+	if path == string(os.PathSeparator) {
+		return true, true, nil
 	}
+
+	// Try a fast path, using openat2() with RESOLVE_NO_XDEV.
+	mounted, err = mountedByOpenat2(path)
+	if err == nil {
+		return mounted, true, nil
+	}
+
 	// Another fast path: compare st.st_dev fields.
 	mounted, err = mountedByStat(path)
 	// This does not work for bind mounts, so false negative
 	// is possible, therefore only trust if return is true.
 	if mounted && err == nil {
+		return true, true, nil
+	}
+
+	return
+}
+
+func mounted(path string) (bool, error) {
+	path, err := normalizePath(path)
+	if err != nil {
+		return false, err
+	}
+	mounted, sure, err := mountedFast(path)
+	if sure && err == nil {
 		return mounted, nil
 	}
 
-	// Fallback to parsing mountinfo
+	// Fallback to parsing mountinfo.
 	return mountedByMountinfo(path)
 }

vendor/github.com/moby/sys/mountinfo/mounted_unix.go

@@ -1,9 +1,9 @@
-// +build linux freebsd,cgo openbsd,cgo
+//go:build linux || (freebsd && cgo) || (openbsd && cgo) || (darwin && cgo)
+// +build linux freebsd,cgo openbsd,cgo darwin,cgo
 
 package mountinfo
 
 import (
-	"errors"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -15,10 +15,6 @@ func mountedByStat(path string) (bool, error) {
 	var st unix.Stat_t
 
 	if err := unix.Lstat(path, &st); err != nil {
-		if err == unix.ENOENT {
-			// Treat ENOENT as "not mounted".
-			return false, nil
-		}
 		return false, &os.PathError{Op: "stat", Path: path, Err: err}
 	}
 	dev := st.Dev
@@ -49,14 +45,6 @@ func normalizePath(path string) (realPath string, err error) {
 }
 
 func mountedByMountinfo(path string) (bool, error) {
-	path, err := normalizePath(path)
-	if err != nil {
-		if errors.Is(err, unix.ENOENT) {
-			// treat ENOENT as "not mounted"
-			return false, nil
-		}
-		return false, err
-	}
 	entries, err := GetMounts(SingleEntryFilter(path))
 	if err != nil {
 		return false, err

vendor/github.com/moby/sys/mountinfo/mountinfo.go

@@ -10,11 +10,12 @@ func GetMounts(f FilterFunc) ([]*Info, error) {
 	return parseMountTable(f)
 }
 
-// Mounted determines if a specified path is a mount point.
+// Mounted determines if a specified path is a mount point. In case of any
+// error, false (and an error) is returned.
 //
-// The argument must be an absolute path, with all symlinks resolved, and clean.
-// One way to ensure it is to process the path using filepath.Abs followed by
-// filepath.EvalSymlinks before calling this function.
+// If a non-existent path is specified, an appropriate error is returned.
+// In case the caller is not interested in this particular error, it should
+// be handled separately using e.g. errors.Is(err, os.ErrNotExist).
 func Mounted(path string) (bool, error) {
 	// root is always mounted
 	if path == string(os.PathSeparator) {

vendor/github.com/moby/sys/mountinfo/mountinfo_bsd.go

@@ -1,4 +1,5 @@
-// +build freebsd,cgo openbsd,cgo
+//go:build (freebsd && cgo) || (openbsd && cgo) || (darwin && cgo)
+// +build freebsd,cgo openbsd,cgo darwin,cgo
 
 package mountinfo
 
@@ -21,7 +22,7 @@ func parseMountTable(filter FilterFunc) ([]*Info, error) {
 
 	count := int(C.getmntinfo(&rawEntries, C.MNT_WAIT))
 	if count == 0 {
-		return nil, fmt.Errorf("Failed to call getmntinfo")
+		return nil, fmt.Errorf("failed to call getmntinfo")
 	}
 
 	var entries []C.struct_statfs
@@ -55,6 +56,10 @@ func parseMountTable(filter FilterFunc) ([]*Info, error) {
 }
 
 func mounted(path string) (bool, error) {
+	path, err := normalizePath(path)
+	if err != nil {
+		return false, err
+	}
 	// Fast path: compare st.st_dev fields.
 	// This should always work for FreeBSD and OpenBSD.
 	mounted, err := mountedByStat(path)

vendor/github.com/moby/sys/mountinfo/mountinfo_linux.go

@@ -52,7 +52,7 @@ func GetMountsFromReader(r io.Reader, filter FilterFunc) ([]*Info, error) {
 		numFields := len(fields)
 		if numFields < 10 {
 			// should be at least 10 fields
-			return nil, fmt.Errorf("Parsing '%s' failed: not enough fields (%d)", text, numFields)
+			return nil, fmt.Errorf("parsing '%s' failed: not enough fields (%d)", text, numFields)
 		}
 
 		// separator field
@@ -67,7 +67,7 @@ func GetMountsFromReader(r io.Reader, filter FilterFunc) ([]*Info, error) {
 		for fields[sepIdx] != "-" {
 			sepIdx--
 			if sepIdx == 5 {
-				return nil, fmt.Errorf("Parsing '%s' failed: missing - separator", text)
+				return nil, fmt.Errorf("parsing '%s' failed: missing - separator", text)
 			}
 		}
 
@@ -75,46 +75,39 @@ func GetMountsFromReader(r io.Reader, filter FilterFunc) ([]*Info, error) {
 
 		p.Mountpoint, err = unescape(fields[4])
 		if err != nil {
-			return nil, fmt.Errorf("Parsing '%s' failed: mount point: %w", fields[4], err)
+			return nil, fmt.Errorf("parsing '%s' failed: mount point: %w", fields[4], err)
 		}
 		p.FSType, err = unescape(fields[sepIdx+1])
 		if err != nil {
-			return nil, fmt.Errorf("Parsing '%s' failed: fstype: %w", fields[sepIdx+1], err)
+			return nil, fmt.Errorf("parsing '%s' failed: fstype: %w", fields[sepIdx+1], err)
 		}
 		p.Source, err = unescape(fields[sepIdx+2])
 		if err != nil {
-			return nil, fmt.Errorf("Parsing '%s' failed: source: %w", fields[sepIdx+2], err)
+			return nil, fmt.Errorf("parsing '%s' failed: source: %w", fields[sepIdx+2], err)
 		}
 		p.VFSOptions = fields[sepIdx+3]
 
 		// ignore any numbers parsing errors, as there should not be any
 		p.ID, _ = strconv.Atoi(fields[0])
 		p.Parent, _ = strconv.Atoi(fields[1])
-		mm := strings.Split(fields[2], ":")
+		mm := strings.SplitN(fields[2], ":", 3)
 		if len(mm) != 2 {
-			return nil, fmt.Errorf("Parsing '%s' failed: unexpected minor:major pair %s", text, mm)
+			return nil, fmt.Errorf("parsing '%s' failed: unexpected major:minor pair %s", text, mm)
 		}
 		p.Major, _ = strconv.Atoi(mm[0])
 		p.Minor, _ = strconv.Atoi(mm[1])
 
 		p.Root, err = unescape(fields[3])
 		if err != nil {
-			return nil, fmt.Errorf("Parsing '%s' failed: root: %w", fields[3], err)
+			return nil, fmt.Errorf("parsing '%s' failed: root: %w", fields[3], err)
 		}
 
 		p.Options = fields[5]
 
 		// zero or more optional fields
-		switch {
-		case sepIdx == 6:
-			// zero, do nothing
-		case sepIdx == 7:
-			p.Optional = fields[6]
-		default:
-			p.Optional = strings.Join(fields[6:sepIdx-1], " ")
-		}
+		p.Optional = strings.Join(fields[6:sepIdx], " ")
 
-		// Run the filter after parsing all of the fields.
+		// Run the filter after parsing all fields.
 		var skip, stop bool
 		if filter != nil {
 			skip, stop = filter(p)

vendor/github.com/moby/sys/mountinfo/mountinfo_unsupported.go

@@ -1,4 +1,5 @@
-// +build !windows,!linux,!freebsd,!openbsd freebsd,!cgo openbsd,!cgo
+//go:build (!windows && !linux && !freebsd && !openbsd && !darwin) || (freebsd && !cgo) || (openbsd && !cgo) || (darwin && !cgo)
+// +build !windows,!linux,!freebsd,!openbsd,!darwin freebsd,!cgo openbsd,!cgo darwin,!cgo
 
 package mountinfo