1// +build !windows
2
3package archive // import "github.com/ory/dockertest/docker/pkg/archive"
4
5import (
6	"archive/tar"
7	"bufio"
8	"errors"
9	"fmt"
10	"os"
11	"path/filepath"
12	"syscall"
13
14	"github.com/ory/dockertest/docker/pkg/idtools"
15	"github.com/ory/dockertest/docker/pkg/system"
16	"golang.org/x/sys/unix"
17)
18
19// fixVolumePathPrefix does platform specific processing to ensure that if
20// the path being passed in is not in a volume path format, convert it to one.
21func fixVolumePathPrefix(srcPath string) string {
22	return srcPath
23}
24
25// getWalkRoot calculates the root path when performing a TarWithOptions.
26// We use a separate function as this is platform specific. On Linux, we
27// can't use filepath.Join(srcPath,include) because this will clean away
28// a trailing "." or "/" which may be important.
29func getWalkRoot(srcPath string, include string) string {
30	return srcPath + string(filepath.Separator) + include
31}
32
33// CanonicalTarNameForPath returns platform-specific filepath
34// to canonical posix-style path for tar archival. p is relative
35// path.
36func CanonicalTarNameForPath(p string) (string, error) {
37	return p, nil // already unix-style
38}
39
40// chmodTarEntry is used to adjust the file permissions used in tar header based
41// on the platform the archival is done.
42
43func chmodTarEntry(perm os.FileMode) os.FileMode {
44	return perm // noop for unix as golang APIs provide perm bits correctly
45}
46
47func setHeaderForSpecialDevice(hdr *tar.Header, name string, stat interface{}) (err error) {
48	s, ok := stat.(*syscall.Stat_t)
49
50	if ok {
51		// Currently go does not fill in the major/minors
52		if s.Mode&unix.S_IFBLK != 0 ||
53			s.Mode&unix.S_IFCHR != 0 {
54			hdr.Devmajor = int64(unix.Major(uint64(s.Rdev))) // nolint: unconvert
55			hdr.Devminor = int64(unix.Minor(uint64(s.Rdev))) // nolint: unconvert
56		}
57	}
58
59	return
60}
61
62func getInodeFromStat(stat interface{}) (inode uint64, err error) {
63	s, ok := stat.(*syscall.Stat_t)
64
65	if ok {
66		inode = s.Ino
67	}
68
69	return
70}
71
72func getFileUIDGID(stat interface{}) (idtools.IDPair, error) {
73	s, ok := stat.(*syscall.Stat_t)
74
75	if !ok {
76		return idtools.IDPair{}, errors.New("cannot convert stat value to syscall.Stat_t")
77	}
78	return idtools.IDPair{UID: int(s.Uid), GID: int(s.Gid)}, nil
79}
80
81// handleTarTypeBlockCharFifo is an OS-specific helper function used by
82// createTarFile to handle the following types of header: Block; Char; Fifo
83func handleTarTypeBlockCharFifo(hdr *tar.Header, path string) error {
84	if runningInUserNS() {
85		// cannot create a device if running in user namespace
86		return nil
87	}
88
89	mode := uint32(hdr.Mode & 07777)
90	switch hdr.Typeflag {
91	case tar.TypeBlock:
92		mode |= unix.S_IFBLK
93	case tar.TypeChar:
94		mode |= unix.S_IFCHR
95	case tar.TypeFifo:
96		mode |= unix.S_IFIFO
97	}
98
99	return system.Mknod(path, mode, int(system.Mkdev(hdr.Devmajor, hdr.Devminor)))
100}
101
102func handleLChmod(hdr *tar.Header, path string, hdrInfo os.FileInfo) error {
103	if hdr.Typeflag == tar.TypeLink {
104		if fi, err := os.Lstat(hdr.Linkname); err == nil && (fi.Mode()&os.ModeSymlink == 0) {
105			if err := os.Chmod(path, hdrInfo.Mode()); err != nil {
106				return err
107			}
108		}
109	} else if hdr.Typeflag != tar.TypeSymlink {
110		if err := os.Chmod(path, hdrInfo.Mode()); err != nil {
111			return err
112		}
113	}
114	return nil
115}
116
117// runningInUserNS detects whether we are currently running in a user namespace.
118// Copied from github.com/opencontainers/runc/libcontainer/system/linux.go
119// Copied from github.com/lxc/lxd/shared/util.go
120func runningInUserNS() bool {
121	file, err := os.Open("/proc/self/uid_map")
122	if err != nil {
123		// This kernel-provided file only exists if user namespaces are supported
124		return false
125	}
126	defer file.Close()
127
128	buf := bufio.NewReader(file)
129	l, _, err := buf.ReadLine()
130	if err != nil {
131		return false
132	}
133
134	line := string(l)
135	var a, b, c int64
136	fmt.Sscanf(line, "%d %d %d", &a, &b, &c)
137	/*
138	 * We assume we are in the initial user namespace if we have a full
139	 * range - 4294967295 uids starting at uid 0.
140	 */
141	if a == 0 && b == 0 && c == 4294967295 {
142		return false
143	}
144	return true
145}
146