3c878aefe8
Mount is self contained and generic, it should be in pkg, to allow other pkg modules to use it. Docker-DCO-1.1-Signed-off-by: Paul Nasrat <pnasrat@gmail.com> (github: pnasrat)
79 lines
2.2 KiB
Go
79 lines
2.2 KiB
Go
package mount
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import (
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"bufio"
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"fmt"
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"io"
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"os"
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"strings"
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)
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const (
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/* 36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
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(1)(2)(3) (4) (5) (6) (7) (8) (9) (10) (11)
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(1) mount ID: unique identifier of the mount (may be reused after umount)
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(2) parent ID: ID of parent (or of self for the top of the mount tree)
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(3) major:minor: value of st_dev for files on filesystem
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(4) root: root of the mount within the filesystem
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(5) mount point: mount point relative to the process's root
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(6) mount options: per mount options
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(7) optional fields: zero or more fields of the form "tag[:value]"
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(8) separator: marks the end of the optional fields
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(9) filesystem type: name of filesystem of the form "type[.subtype]"
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(10) mount source: filesystem specific information or "none"
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(11) super options: per super block options*/
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mountinfoFormat = "%d %d %d:%d %s %s %s "
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)
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type MountInfo struct {
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Id, Parent, Major, Minor int
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Root, Mountpoint, Opts string
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Fstype, Source, VfsOpts string
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}
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// Parse /proc/self/mountinfo because comparing Dev and ino does not work from bind mounts
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func parseMountTable() ([]*MountInfo, error) {
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f, err := os.Open("/proc/self/mountinfo")
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if err != nil {
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return nil, err
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}
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defer f.Close()
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return parseInfoFile(f)
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}
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func parseInfoFile(r io.Reader) ([]*MountInfo, error) {
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var (
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s = bufio.NewScanner(r)
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out = []*MountInfo{}
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)
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for s.Scan() {
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if err := s.Err(); err != nil {
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return nil, err
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}
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var (
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p = &MountInfo{}
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text = s.Text()
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)
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if _, err := fmt.Sscanf(text, mountinfoFormat,
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&p.Id, &p.Parent, &p.Major, &p.Minor,
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&p.Root, &p.Mountpoint, &p.Opts); err != nil {
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return nil, fmt.Errorf("Scanning '%s' failed: %s", text, err)
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}
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// Safe as mountinfo encodes mountpoints with spaces as \040.
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index := strings.Index(text, " - ")
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postSeparatorFields := strings.Fields(text[index+3:])
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if len(postSeparatorFields) != 3 {
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return nil, fmt.Errorf("Error did not find 3 fields post '-' in '%s'", text)
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}
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p.Fstype = postSeparatorFields[0]
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p.Source = postSeparatorFields[1]
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p.VfsOpts = postSeparatorFields[2]
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out = append(out, p)
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}
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return out, nil
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}
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