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fix(linux): isInContainer works for current docker versions #406

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fix(linux): isInContainer works for current docker versions #406

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62 changes: 60 additions & 2 deletions service_linux.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -6,13 +6,16 @@ package service

import (
"bufio"
"errors"
"fmt"
"io/ioutil"
"os"
"strings"
)

var cgroupFile = "/proc/1/cgroup"
var mountInfoFile = "/proc/self/mountinfo"
var dockerEnvFile = "/.dockerenv"

type linuxSystemService struct {
name string
Expand Down Expand Up @@ -98,7 +101,7 @@ func binaryName(pid int) (string, error) {
}

func isInteractive() (bool, error) {
inContainer, err := isInContainer(cgroupFile)
inContainer, err := isInContainer()
if err != nil {
return false, err
}
Expand All @@ -118,7 +121,62 @@ func isInteractive() (bool, error) {

// isInContainer checks if the service is being executed in docker or lxc
// container.
func isInContainer(cgroupPath string) (bool, error) {
func isInContainer() (bool, error) {
inContainer, err := isInContainerDockerEnv(dockerEnvFile)
if err != nil {
return false, err
}
if inContainer {
return true, nil
}

inContainer, err = isInContainerCGroup(cgroupFile)
if err != nil {
return false, err
}
if inContainer {
return true, nil
}

return isInContainerMountInfo(mountInfoFile)
}

func isInContainerDockerEnv(filePath string) (bool, error) {
_, err := os.Stat(filePath)
if err == nil {
return true, nil
}
if errors.Is(err, os.ErrNotExist) {
return false, nil
}

return false, err
}

func isInContainerMountInfo(filePath string) (bool, error) {
const maxlines = 15 // maximum lines to scan
f, err := os.Open(filePath)
if err != nil {
return false, err
}
defer f.Close()
scan := bufio.NewScanner(f)

lines := 0
for scan.Scan() && !(lines > maxlines) {
if strings.Contains(scan.Text(), "/docker/containers") {
return true, nil
}
lines++
}
if err := scan.Err(); err != nil {
return false, err
}

return false, nil
}

func isInContainerCGroup(cgroupPath string) (bool, error) {
const maxlines = 5 // maximum lines to scan

f, err := os.Open(cgroupPath)
Expand Down
129 changes: 126 additions & 3 deletions service_linux_test.go
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -36,13 +36,38 @@ func createTestCgroupFiles() (*os.File, *os.File, error) {
return hDockerGrp, hLinuxGrp, nil
}

// createTestMountInfoFiles creates mock files for tests
func createTestMountInfoFiles() (*os.File, *os.File, error) {
// docker cgroup setup
hDockerGrp, err := os.CreateTemp("", "*")
if err != nil {
return nil, nil, errors.New("docker tempfile create failed")
}
_, err = hDockerGrp.Write([]byte(dockerMountInfo))
if err != nil {
return nil, nil, errors.New("docker tempfile write failed")
}

// linux cgroup setup
hLinuxGrp, err := os.CreateTemp("", "*")
if err != nil {
return nil, nil, errors.New("\"normal\" tempfile create failed")
}
_, err = hLinuxGrp.Write([]byte(linuxMountInfo))
if err != nil {
return nil, nil, errors.New("\"normal\" tempfile write failed")
}

return hDockerGrp, hLinuxGrp, nil
}

// removeTestFile closes and removes the provided file
func removeTestFile(hFile *os.File) {
hFile.Close()
os.Remove(hFile.Name())
}

func Test_isInContainer(t *testing.T) {
func Test_isInContainerCGroup(t *testing.T) {

// setup
hDockerGrp, hLinuxGrp, err := createTestCgroupFiles()
Expand All @@ -57,7 +82,46 @@ func Test_isInContainer(t *testing.T) {

// TEST
type args struct {
cgroupPath string
filePath string
}
tests := []struct {
name string
args args
want bool
wantErr bool
}{
{"docker", args{hDockerGrp.Name()}, true, false},
{"linux", args{hLinuxGrp.Name()}, false, false},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got, err := isInContainerCGroup(tt.args.filePath)
if (err != nil) != tt.wantErr {
t.Errorf("isInContainer() error = %v, wantErr %v", err, tt.wantErr)
return
}
if got != tt.want {
t.Errorf("isInContainer() = %v, want %v", got, tt.want)
}
})
}
}
func Test_isInContainerMountInfo(t *testing.T) {

// setup
hDockerGrp, hLinuxGrp, err := createTestMountInfoFiles()
if err != nil {
t.Fatal(err)
}
defer func() {
// tear down
removeTestFile(hDockerGrp)
removeTestFile(hLinuxGrp)
}()

// TEST
type args struct {
filePath string
}
tests := []struct {
name string
Expand All @@ -70,7 +134,36 @@ func Test_isInContainer(t *testing.T) {
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got, err := isInContainer(tt.args.cgroupPath)
got, err := isInContainerMountInfo(tt.args.filePath)
if (err != nil) != tt.wantErr {
t.Errorf("isInContainer() error = %v, wantErr %v", err, tt.wantErr)
return
}
if got != tt.want {
t.Errorf("isInContainer() = %v, want %v", got, tt.want)
}
})
}
}

func Test_isInContainerDockerEnv(t *testing.T) {

// TEST
type args struct {
filePath string
}
tests := []struct {
name string
args args
want bool
wantErr bool
}{
{"docker", args{os.TempDir()}, true, false},
{"linux", args{"/non_existent_file"}, false, false},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got, err := isInContainerDockerEnv(tt.args.filePath)
if (err != nil) != tt.wantErr {
t.Errorf("isInContainer() error = %v, wantErr %v", err, tt.wantErr)
return
Expand Down Expand Up @@ -170,4 +263,34 @@ const (
2:cpu,cpuacct:/
1:name=systemd:/init.scope
0::/init.scope`

dockerMountInfo = `3860 3859 0:159 / /dev/pts rw,nosuid,noexec,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=666
3861 3857 0:160 / /sys ro,nosuid,nodev,noexec,relatime - sysfs sysfs ro
3862 3861 0:29 / /sys/fs/cgroup ro,nosuid,nodev,noexec,relatime - cgroup2 cgroup rw
3863 3859 0:156 / /dev/mqueue rw,nosuid,nodev,noexec,relatime - mqueue mqueue rw
3864 3859 0:161 / /dev/shm rw,nosuid,nodev,noexec,relatime - tmpfs shm rw,size=65536k,inode64
3865 3857 259:4 /var/lib/docker/volumes/345b0c4550daa5dbc7f4fa9fbd28717844e69e235f2aa014c7d24114320dd9a1/_data /opt/data rw,relatime master:1 - ext4 /dev/nvme0n1p4 rw
3866 3857 259:4 /var/lib/docker/containers/ea4d56df6742a4940bfa0b31a4481707511f2da7b7c0708ffe901b46f461eb89/resolv.conf /etc/resolv.conf rw,relatime - ext4 /dev/nvme0n1p4 rw
3867 3857 259:4 /var/lib/docker/containers/ea4d56df6742a4940bfa0b31a4481707511f2da7b7c0708ffe901b46f461eb89/hostname /etc/hostname rw,relatime - ext4 /dev/nvme0n1p4 rw
3868 3857 259:4 /var/lib/docker/containers/ea4d56df6742a4940bfa0b31a4481707511f2da7b7c0708ffe901b46f461eb89/hosts /etc/hosts rw,relatime - ext4 /dev/nvme0n1p4 rw
3776 3859 0:159 /0 /dev/console rw,nosuid,noexec,relatime - devpts devpts rw,gid=5,mode=620,ptmxmode=666
3777 3858 0:157 /bus /proc/bus ro,nosuid,nodev,noexec,relatime - proc proc rw
3778 3858 0:157 /fs /proc/fs ro,nosuid,nodev,noexec,relatime - proc proc rw`

linuxMountInfo = `183 28 0:44 / /run/credentials/systemd-tmpfiles-setup.service ro,nosuid,nodev,noexec,relatime,nosymfollow shared:103 - tmpfs tmpfs rw,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
129 36 0:45 / /proc/sys/fs/binfmt_misc rw,nosuid,nodev,noexec,relatime shared:105 - binfmt_misc binfmt_misc rw
407 28 0:48 / /run/credentials/systemd-resolved.service ro,nosuid,nodev,noexec,relatime,nosymfollow shared:107 - tmpfs tmpfs rw,size=1024k,nr_inodes=1024,mode=700,inode64,noswap
166 30 0:60 / /var/lib/lxcfs rw,nosuid,nodev,relatime shared:329 - fuse.lxcfs lxcfs rw,user_id=0,group_id=0,allow_other
217 28 0:67 / /run/rpc_pipefs rw,relatime shared:911 - rpc_pipefs sunrpc rw
298 28 0:26 /snapd/ns /run/snapd/ns rw,nosuid,nodev,noexec,relatime - tmpfs tmpfs rw,size=4066576k,mode=755,inode64
335 298 0:4 mnt:[4026533124] /run/snapd/ns/cups.mnt rw - nsfs nsfs rw
1821 298 0:4 mnt:[4026533318] /run/snapd/ns/snapd-desktop-integration.mnt rw - nsfs nsfs rw
169 28 0:64 / /run/user/1000 rw,nosuid,nodev,relatime shared:700 - tmpfs tmpfs rw,size=4066576k,nr_inodes=1016644,mode=700,uid=1000,gid=1000,inode64
924 169 0:65 / /run/user/1000/doc rw,nosuid,nodev,relatime shared:794 - fuse.portal portal rw,user_id=1000,group_id=1000
2388 169 0:71 / /run/user/1000/gvfs rw,nosuid,nodev,relatime shared:814 - fuse.gvfsd-fuse gvfsd-fuse rw,user_id=1000,group_id=1000
2948 298 0:4 mnt:[4026534753] /run/snapd/ns/firmware-updater.mnt rw - nsfs nsfs rw
3517 30 0:129 / /var/lib/docker/overlay2/79490de289b65b7a63e86a6ae48a8607cf251030eec80d554f99eff740ba425e/merged rw,relatime shared:834 - overlay overlay rw,lowerdir=/var/lib/docker/overlay2/l/FCSCRZU3XZN6KVYV6UA4IU6CZM:/var/lib/docker/overlay2/l/I7GRZ2AVB7NO3MPA7VF75DF25N:/var/lib/docker/overlay2/l/3PHQOMHS6SD5HZFMUUENIQXENT:/var/lib/docker/overlay2/l/YOR22M55ADQZ4GRJIW3NR4EKF3:/var/lib/docker/overlay2/l/SLIJGALM6YROVNIV62WO7HLAXT,upperdir=/var/lib/docker/overlay2/79490de289b65b7a63e86a6ae48a8607cf251030eec80d554f99eff740ba425e/diff,workdir=/var/lib/docker/overlay2/79490de289b65b7a63e86a6ae48a8607cf251030eec80d554f99eff740ba425e/work,nouserxattr
3623 28 0:4 net:[4026537044] /run/docker/netns/e63556d83137 rw shared:1054 - nsfs nsfs rw
3548 30 0:137 / /var/lib/docker/overlay2/5f0fd269ad76199040b9b3ca1fa13ce36f9ab6799cd4b0b5406732c2c8407ff6/merged rw,relatime shared:1074 - overlay overlay rw,lowerdir=/var/lib/docker/overlay2/l/SXPONMLN4JW3QBFQWXCZ3RHVST:/var/lib/docker/overlay2/l/LA6JENXEZAPXZZF2FP4ON5WDEA:/var/lib/docker/overlay2/l/XEGVGERQJ7L72RWT3VIXEWGBL4:/var/lib/docker/overlay2/l/BPXXR3DHMVCSQWGSXG5NFNBE5W,upperdir=/var/lib/docker/overlay2/5f0fd269ad76199040b9b3ca1fa13ce36f9ab6799cd4b0b5406732c2c8407ff6/diff,workdir=/var/lib/docker/overlay2/5f0fd269ad76199040b9b3ca1fa13ce36f9ab6799cd4b0b5406732c2c8407ff6/work,nouserxattr
3700 28 0:4 net:[4026537144] /run/docker/netns/0b489b9c590d rw shared:1094 - nsfs nsfs rw`
)