rebase: update k8s.io/mount-utils to current master

kubernetes/kubernetes#111083 has been merged and synced into
k8s.io/mount-utils. This should remove any systemd log messages while
calling NodeStageVolume and NodeGetVolumeStats.

Signed-off-by: Niels de Vos <ndevos@redhat.com>

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

@@ -0,0 +1,214 @@
+package mountinfo
+
+import (
+	"bufio"
+	"fmt"
+	"io"
+	"os"
+	"strconv"
+	"strings"
+)
+
+// GetMountsFromReader retrieves a list of mounts from the
+// reader provided, with an optional filter applied (use nil
+// for no filter). This can be useful in tests or benchmarks
+// that provide fake mountinfo data, or when a source other
+// than /proc/self/mountinfo needs to be read from.
+//
+// This function is Linux-specific.
+func GetMountsFromReader(r io.Reader, filter FilterFunc) ([]*Info, error) {
+	s := bufio.NewScanner(r)
+	out := []*Info{}
+	for s.Scan() {
+		var err error
+
+		/*
+		   See http://man7.org/linux/man-pages/man5/proc.5.html
+
+		   36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
+		   (1)(2)(3)   (4)   (5)      (6)      (7)   (8) (9)   (10)         (11)
+
+		   (1) mount ID:  unique identifier of the mount (may be reused after umount)
+		   (2) parent ID:  ID of parent (or of self for the top of the mount tree)
+		   (3) major:minor:  value of st_dev for files on filesystem
+		   (4) root:  root of the mount within the filesystem
+		   (5) mount point:  mount point relative to the process's root
+		   (6) mount options:  per mount options
+		   (7) optional fields:  zero or more fields of the form "tag[:value]"
+		   (8) separator:  marks the end of the optional fields
+		   (9) filesystem type:  name of filesystem of the form "type[.subtype]"
+		   (10) mount source:  filesystem specific information or "none"
+		   (11) super options:  per super block options
+
+		   In other words, we have:
+		    * 6 mandatory fields	(1)..(6)
+		    * 0 or more optional fields	(7)
+		    * a separator field		(8)
+		    * 3 mandatory fields	(9)..(11)
+		*/
+
+		text := s.Text()
+		fields := strings.Split(text, " ")
+		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)
+		}
+
+		// separator field
+		sepIdx := numFields - 4
+		// In Linux <= 3.9 mounting a cifs with spaces in a share
+		// name (like "//srv/My Docs") _may_ end up having a space
+		// in the last field of mountinfo (like "unc=//serv/My Docs").
+		// Since kernel 3.10-rc1, cifs option "unc=" is ignored,
+		// so spaces should not appear.
+		//
+		// Check for a separator, and work around the spaces bug
+		for fields[sepIdx] != "-" {
+			sepIdx--
+			if sepIdx == 5 {
+				return nil, fmt.Errorf("parsing '%s' failed: missing - separator", text)
+			}
+		}
+
+		p := &Info{}
+
+		p.Mountpoint, err = unescape(fields[4])
+		if err != nil {
+			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)
+		}
+		p.Source, err = unescape(fields[sepIdx+2])
+		if err != nil {
+			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.SplitN(fields[2], ":", 3)
+		if len(mm) != 2 {
+			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)
+		}
+
+		p.Options = fields[5]
+
+		// zero or more optional fields
+		p.Optional = strings.Join(fields[6:sepIdx], " ")
+
+		// Run the filter after parsing all fields.
+		var skip, stop bool
+		if filter != nil {
+			skip, stop = filter(p)
+			if skip {
+				continue
+			}
+		}
+
+		out = append(out, p)
+		if stop {
+			break
+		}
+	}
+	if err := s.Err(); err != nil {
+		return nil, err
+	}
+	return out, nil
+}
+
+func parseMountTable(filter FilterFunc) ([]*Info, error) {
+	f, err := os.Open("/proc/self/mountinfo")
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	return GetMountsFromReader(f, filter)
+}
+
+// PidMountInfo retrieves the list of mounts from a given process' mount
+// namespace. Unless there is a need to get mounts from a mount namespace
+// different from that of a calling process, use GetMounts.
+//
+// This function is Linux-specific.
+//
+// Deprecated: this will be removed before v1; use GetMountsFromReader with
+// opened /proc/<pid>/mountinfo as an argument instead.
+func PidMountInfo(pid int) ([]*Info, error) {
+	f, err := os.Open(fmt.Sprintf("/proc/%d/mountinfo", pid))
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	return GetMountsFromReader(f, nil)
+}
+
+// A few specific characters in mountinfo path entries (root and mountpoint)
+// are escaped using a backslash followed by a character's ascii code in octal.
+//
+//   space              -- as \040
+//   tab (aka \t)       -- as \011
+//   newline (aka \n)   -- as \012
+//   backslash (aka \\) -- as \134
+//
+// This function converts path from mountinfo back, i.e. it unescapes the above sequences.
+func unescape(path string) (string, error) {
+	// try to avoid copying
+	if strings.IndexByte(path, '\\') == -1 {
+		return path, nil
+	}
+
+	// The following code is UTF-8 transparent as it only looks for some
+	// specific characters (backslash and 0..7) with values < utf8.RuneSelf,
+	// and everything else is passed through as is.
+	buf := make([]byte, len(path))
+	bufLen := 0
+	for i := 0; i < len(path); i++ {
+		if path[i] != '\\' {
+			buf[bufLen] = path[i]
+			bufLen++
+			continue
+		}
+		s := path[i:]
+		if len(s) < 4 {
+			// too short
+			return "", fmt.Errorf("bad escape sequence %q: too short", s)
+		}
+		c := s[1]
+		switch c {
+		case '0', '1', '2', '3', '4', '5', '6', '7':
+			v := c - '0'
+			for j := 2; j < 4; j++ { // one digit already; two more
+				if s[j] < '0' || s[j] > '7' {
+					return "", fmt.Errorf("bad escape sequence %q: not a digit", s[:3])
+				}
+				x := s[j] - '0'
+				v = (v << 3) | x
+			}
+			if v > 255 {
+				return "", fmt.Errorf("bad escape sequence %q: out of range" + s[:3])
+			}
+			buf[bufLen] = v
+			bufLen++
+			i += 3
+			continue
+		default:
+			return "", fmt.Errorf("bad escape sequence %q: not a digit" + s[:3])
+
+		}
+	}
+
+	return string(buf[:bufLen]), nil
+}