mirror of
https://github.com/superseriousbusiness/gotosocial.git
synced 2024-12-05 14:40:42 +01:00
172 lines
5.0 KiB
Go
172 lines
5.0 KiB
Go
// Copyright (c) 2017 Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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//go:build linux
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// +build linux
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package cgroups
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import (
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"bufio"
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"os"
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"path/filepath"
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"strconv"
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"strings"
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)
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const (
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_mountInfoSep = " "
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_mountInfoOptsSep = ","
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_mountInfoOptionalFieldsSep = "-"
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)
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const (
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_miFieldIDMountID = iota
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_miFieldIDParentID
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_miFieldIDDeviceID
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_miFieldIDRoot
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_miFieldIDMountPoint
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_miFieldIDOptions
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_miFieldIDOptionalFields
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_miFieldCountFirstHalf
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)
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const (
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_miFieldOffsetFSType = iota
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_miFieldOffsetMountSource
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_miFieldOffsetSuperOptions
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_miFieldCountSecondHalf
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)
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const _miFieldCountMin = _miFieldCountFirstHalf + _miFieldCountSecondHalf
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// MountPoint is the data structure for the mount points in
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// `/proc/$PID/mountinfo`. See also proc(5) for more information.
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type MountPoint struct {
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MountID int
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ParentID int
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DeviceID string
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Root string
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MountPoint string
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Options []string
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OptionalFields []string
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FSType string
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MountSource string
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SuperOptions []string
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}
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// NewMountPointFromLine parses a line read from `/proc/$PID/mountinfo` and
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// returns a new *MountPoint.
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func NewMountPointFromLine(line string) (*MountPoint, error) {
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fields := strings.Split(line, _mountInfoSep)
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if len(fields) < _miFieldCountMin {
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return nil, mountPointFormatInvalidError{line}
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}
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mountID, err := strconv.Atoi(fields[_miFieldIDMountID])
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if err != nil {
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return nil, err
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}
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parentID, err := strconv.Atoi(fields[_miFieldIDParentID])
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if err != nil {
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return nil, err
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}
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for i, field := range fields[_miFieldIDOptionalFields:] {
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if field == _mountInfoOptionalFieldsSep {
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// End of optional fields.
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fsTypeStart := _miFieldIDOptionalFields + i + 1
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// Now we know where the optional fields end, split the line again with a
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// limit to avoid issues with spaces in super options as present on WSL.
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fields = strings.SplitN(line, _mountInfoSep, fsTypeStart+_miFieldCountSecondHalf)
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if len(fields) != fsTypeStart+_miFieldCountSecondHalf {
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return nil, mountPointFormatInvalidError{line}
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}
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miFieldIDFSType := _miFieldOffsetFSType + fsTypeStart
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miFieldIDMountSource := _miFieldOffsetMountSource + fsTypeStart
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miFieldIDSuperOptions := _miFieldOffsetSuperOptions + fsTypeStart
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return &MountPoint{
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MountID: mountID,
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ParentID: parentID,
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DeviceID: fields[_miFieldIDDeviceID],
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Root: fields[_miFieldIDRoot],
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MountPoint: fields[_miFieldIDMountPoint],
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Options: strings.Split(fields[_miFieldIDOptions], _mountInfoOptsSep),
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OptionalFields: fields[_miFieldIDOptionalFields:(fsTypeStart - 1)],
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FSType: fields[miFieldIDFSType],
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MountSource: fields[miFieldIDMountSource],
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SuperOptions: strings.Split(fields[miFieldIDSuperOptions], _mountInfoOptsSep),
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}, nil
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}
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}
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return nil, mountPointFormatInvalidError{line}
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}
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// Translate converts an absolute path inside the *MountPoint's file system to
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// the host file system path in the mount namespace the *MountPoint belongs to.
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func (mp *MountPoint) Translate(absPath string) (string, error) {
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relPath, err := filepath.Rel(mp.Root, absPath)
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if err != nil {
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return "", err
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}
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if relPath == ".." || strings.HasPrefix(relPath, "../") {
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return "", pathNotExposedFromMountPointError{
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mountPoint: mp.MountPoint,
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root: mp.Root,
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path: absPath,
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}
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}
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return filepath.Join(mp.MountPoint, relPath), nil
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}
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// parseMountInfo parses procPathMountInfo (usually at `/proc/$PID/mountinfo`)
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// and yields parsed *MountPoint into newMountPoint.
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func parseMountInfo(procPathMountInfo string, newMountPoint func(*MountPoint) error) error {
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mountInfoFile, err := os.Open(procPathMountInfo)
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if err != nil {
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return err
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}
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defer mountInfoFile.Close()
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scanner := bufio.NewScanner(mountInfoFile)
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for scanner.Scan() {
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mountPoint, err := NewMountPointFromLine(scanner.Text())
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if err != nil {
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return err
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}
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if err := newMountPoint(mountPoint); err != nil {
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return err
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}
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}
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return scanner.Err()
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}
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