d7af92e00c
This moves both the Mount type and mountinfo into a single mount package. This also opens up the root of the repo to hold the containerd client implementation. Signed-off-by: Michael Crosby <crosbymichael@gmail.com>
95 lines
2.5 KiB
Go
95 lines
2.5 KiB
Go
// +build linux
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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 %s"
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)
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// Self retrieves a list of mounts for the current running process.
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func Self() ([]Info, 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) ([]Info, error) {
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var (
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s = bufio.NewScanner(r)
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out = []Info{}
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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 = Info{}
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text = s.Text()
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optionalFields string
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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.Options, &optionalFields); 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 found less than 3 fields post '-' in %q", text)
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}
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if optionalFields != "-" {
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p.Optional = optionalFields
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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.VFSOptions = strings.Join(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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// PID collects the mounts for a specific process ID. If the process
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// ID is unknown, it is better to use `Self` which will inspect
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// "/proc/self/mountinfo" instead.
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func PID(pid int) ([]Info, error) {
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f, err := os.Open(fmt.Sprintf("/proc/%d/mountinfo", pid))
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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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