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

153 lines
4.2 KiB
Go

// +build go1.13
package mountinfo
import (
"bufio"
"fmt"
"io"
"os"
"strconv"
"strings"
)
func parseInfoFile(r io.Reader, filter FilterFunc) ([]*Info, error) {
s := bufio.NewScanner(r)
out := []*Info{}
var err error
for s.Scan() {
if err = s.Err(); err != nil {
return nil, err
}
/*
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{}
// Fill in the fields that a filter might check
p.Mountpoint, err = strconv.Unquote(`"` + fields[4] + `"`)
if err != nil {
return nil, fmt.Errorf("Parsing '%s' failed: unable to unquote mount point field: %w", fields[4], err)
}
p.Fstype = fields[sepIdx+1]
p.Source = fields[sepIdx+2]
p.VfsOpts = fields[sepIdx+3]
// Run a filter soon so we can skip parsing/adding entries
// the caller is not interested in
var skip, stop bool
if filter != nil {
skip, stop = filter(p)
if skip {
continue
}
}
// Fill in the rest of the fields
// 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], ":")
if len(mm) != 2 {
return nil, fmt.Errorf("Parsing '%s' failed: unexpected minor:major pair %s", text, mm)
}
p.Major, _ = strconv.Atoi(mm[0])
p.Minor, _ = strconv.Atoi(mm[1])
p.Root, err = strconv.Unquote(`"` + fields[3] + `"`)
if err != nil {
return nil, fmt.Errorf("Parsing '%s' failed: unable to unquote root field: %w", fields[3], err)
}
p.Opts = 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], " ")
}
out = append(out, p)
if stop {
break
}
}
return out, nil
}
// Parse /proc/self/mountinfo because comparing Dev and ino does not work from
// bind mounts
func parseMountTable(filter FilterFunc) ([]*Info, error) {
f, err := os.Open("/proc/self/mountinfo")
if err != nil {
return nil, err
}
defer f.Close()
return parseInfoFile(f, filter)
}
// PidMountInfo collects the mounts for a specific process ID. If the process
// ID is unknown, it is better to use `GetMounts` which will inspect
// "/proc/self/mountinfo" 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 parseInfoFile(f, nil)
}