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Merge pull request #4503 from dqminh:nested-cgroup 

PiperOrigin-RevId: 354568091
This commit is contained in:
gVisor bot 2021-01-29 11:06:55 -08:00
parent 71623e4068 d8b590581a
commit 25284ae3c9
2 changed files with 143 additions and 22 deletions
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38
runsc/cgroup/cgroup.go
View File

@ -203,6 +203,19 @@ func LoadPaths(pid string) (map[string]string, error) {
}
func loadPathsHelper(cgroup io.Reader) (map[string]string, error) {
// For nested containers, in /proc/self/cgroup we see paths from host,
// which don't exist in container, so recover the container paths here by
// double-checking with /proc/pid/mountinfo
mountinfo, err := os.Open("/proc/self/mountinfo")
if err != nil {
return nil, err
}
defer mountinfo.Close()
return loadPathsHelperWithMountinfo(cgroup, mountinfo)
}
func loadPathsHelperWithMountinfo(cgroup, mountinfo io.Reader) (map[string]string, error) {
paths := make(map[string]string)
scanner := bufio.NewScanner(cgroup)
@ -225,6 +238,31 @@ func loadPathsHelper(cgroup io.Reader) (map[string]string, error) {
if err := scanner.Err(); err != nil {
return nil, err
}
mfScanner := bufio.NewScanner(mountinfo)
for mfScanner.Scan() {
txt := mfScanner.Text()
fields := strings.Fields(txt)
if len(fields) < 9 || fields[len(fields)-3] != "cgroup" {
continue
}
for _, opt := range strings.Split(fields[len(fields)-1], ",") {
// Remove prefix for cgroups with no controller, eg. systemd.
opt = strings.TrimPrefix(opt, "name=")
if cgroupPath, ok := paths[opt]; ok {
root := fields[3]
relCgroupPath, err := filepath.Rel(root, cgroupPath)
if err != nil {
return nil, err
}
paths[opt] = relCgroupPath
}
}
}
if err := mfScanner.Err(); err != nil {
return nil, err
}
return paths, nil
}

127
runsc/cgroup/cgroup_test.go
View File

@ -25,6 +25,39 @@ import (
"gvisor.dev/gvisor/pkg/test/testutil"
)
var debianMountinfo = `
35 24 0:30 / /sys/fs/cgroup ro shared:9 - tmpfs tmpfs ro
36 35 0:31 / /sys/fs/cgroup/unified rw shared:10 - cgroup2 cgroup2 rw
37 35 0:32 / /sys/fs/cgroup/systemd rw - cgroup cgroup rw,name=systemd
41 35 0:36 / /sys/fs/cgroup/cpu,cpuacct rw shared:16 - cgroup cgroup rw,cpu,cpuacct
42 35 0:37 / /sys/fs/cgroup/freezer rw shared:17 - cgroup cgroup rw,freezer
43 35 0:38 / /sys/fs/cgroup/hugetlb rw shared:18 - cgroup cgroup rw,hugetlb
44 35 0:39 / /sys/fs/cgroup/cpuset rw shared:19 - cgroup cgroup rw,cpuset
45 35 0:40 / /sys/fs/cgroup/net_cls,net_prio rw shared:20 - cgroup cgroup rw,net_cls,net_prio
46 35 0:41 / /sys/fs/cgroup/pids rw shared:21 - cgroup cgroup rw,pids
47 35 0:42 / /sys/fs/cgroup/perf_event rw shared:22 - cgroup cgroup rw,perf_event
48 35 0:43 / /sys/fs/cgroup/memory rw shared:23 - cgroup cgroup rw,memory
49 35 0:44 / /sys/fs/cgroup/blkio rw shared:24 - cgroup cgroup rw,blkio
50 35 0:45 / /sys/fs/cgroup/devices rw shared:25 - cgroup cgroup rw,devices
51 35 0:46 / /sys/fs/cgroup/rdma rw shared:26 - cgroup cgroup rw,rdma
`
var dindMountinfo = `
1305 1304 0:64 / /sys/fs/cgroup rw - tmpfs tmpfs rw,mode=755
1306 1305 0:32 /docker/136 /sys/fs/cgroup/systemd ro master:11 - cgroup cgroup rw,xattr,name=systemd
1307 1305 0:36 /docker/136 /sys/fs/cgroup/cpu,cpuacct ro master:16 - cgroup cgroup rw,cpu,cpuacct
1308 1305 0:37 /docker/136 /sys/fs/cgroup/freezer ro master:17 - cgroup cgroup rw,freezer
1309 1305 0:38 /docker/136 /sys/fs/cgroup/hugetlb ro master:18 - cgroup cgroup rw,hugetlb
1310 1305 0:39 /docker/136 /sys/fs/cgroup/cpuset ro master:19 - cgroup cgroup rw,cpuset
1311 1305 0:40 /docker/136 /sys/fs/cgroup/net_cls,net_prio ro master:20 - cgroup cgroup rw,net_cls,net_prio
1312 1305 0:41 /docker/136 /sys/fs/cgroup/pids ro master:21 - cgroup cgroup rw,pids
1313 1305 0:42 /docker/136 /sys/fs/cgroup/perf_event ro master:22 - cgroup cgroup rw,perf_event
1314 1305 0:43 /docker/136 /sys/fs/cgroup/memory ro master:23 - cgroup cgroup rw,memory
1316 1305 0:44 /docker/136 /sys/fs/cgroup/blkio ro master:24 - cgroup cgroup rw,blkio
1317 1305 0:45 /docker/136 /sys/fs/cgroup/devices ro master:25 - cgroup cgroup rw,devices
1318 1305 0:46 / /sys/fs/cgroup/rdma ro master:26 - cgroup cgroup rw,rdma
`
func TestUninstallEnoent(t *testing.T) {
c := Cgroup{
// set a non-existent name
@ -653,60 +686,110 @@ func TestPids(t *testing.T) {
func TestLoadPaths(t *testing.T) {
for _, tc := range []struct {
name string
cgroups string
want map[string]string
err string
name string
cgroups string
mountinfo string
want map[string]string
err string
}{
{
name: "abs-path",
cgroups: "0:ctr:/path",
want: map[string]string{"ctr": "/path"},
name: "abs-path-unknown-controller",
cgroups: "0:ctr:/path",
mountinfo: debianMountinfo,
want: map[string]string{"ctr": "/path"},
},
{
name: "rel-path",
cgroups: "0:ctr:rel-path",
want: map[string]string{"ctr": "rel-path"},
name: "rel-path",
cgroups: "0:ctr:rel-path",
mountinfo: debianMountinfo,
want: map[string]string{"ctr": "rel-path"},
},
{
name: "non-controller",
cgroups: "0:name=systemd:/path",
want: map[string]string{"systemd": "/path"},
name: "non-controller",
cgroups: "0:name=systemd:/path",
mountinfo: debianMountinfo,
want: map[string]string{"systemd": "path"},
},
{
name: "empty",
name: "empty",
mountinfo: debianMountinfo,
},
{
name: "multiple",
cgroups: "0:ctr0:/path0\n" +
"1:ctr1:/path1\n" +
"2::/empty\n",
mountinfo: debianMountinfo,
want: map[string]string{
"ctr0": "/path0",
"ctr1": "/path1",
},
},
{
name: "missing-field",
cgroups: "0:nopath\n",
err: "invalid cgroups file",
name: "missing-field",
cgroups: "0:nopath\n",
mountinfo: debianMountinfo,
err: "invalid cgroups file",
},
{
name: "too-many-fields",
cgroups: "0:ctr:/path:extra\n",
err: "invalid cgroups file",
name: "too-many-fields",
cgroups: "0:ctr:/path:extra\n",
mountinfo: debianMountinfo,
err: "invalid cgroups file",
},
{
name: "multiple-malformed",
cgroups: "0:ctr0:/path0\n" +
"1:ctr1:/path1\n" +
"2:\n",
err: "invalid cgroups file",
mountinfo: debianMountinfo,
err: "invalid cgroups file",
},
{
name: "nested-cgroup",
cgroups: `9:memory:/docker/136
2:cpu,cpuacct:/docker/136
1:name=systemd:/docker/136
0::/system.slice/containerd.service`,
mountinfo: dindMountinfo,
// we want relative path to /sys/fs/cgroup inside the nested container.
// Subcroup inside the container will be created at /sys/fs/cgroup/cpu
// This will be /sys/fs/cgroup/cpu/docker/136/CGROUP_NAME
// outside the container
want: map[string]string{
"memory": ".",
"cpu": ".",
"cpuacct": ".",
"systemd": ".",
},
},
{
name: "nested-cgroup-submount",
cgroups: "9:memory:/docker/136/test",
mountinfo: dindMountinfo,
want: map[string]string{
"memory": "test",
},
},
{
name: "invalid-mount-info",
cgroups: "0:memory:/path",
mountinfo: "41 35 0:36 / /sys/fs/cgroup/memory rw shared:16 - invalid",
want: map[string]string{
"memory": "/path",
},
},
{
name: "invalid-rel-path-in-proc-cgroup",
cgroups: "9:memory:./invalid",
mountinfo: dindMountinfo,
err: "can't make ./invalid relative to /docker/136",
},
} {
t.Run(tc.name, func(t *testing.T) {
r := strings.NewReader(tc.cgroups)
got, err := loadPathsHelper(r)
mountinfo := strings.NewReader(tc.mountinfo)
got, err := loadPathsHelperWithMountinfo(r, mountinfo)
if len(tc.err) == 0 {
if err != nil {
t.Fatalf("Unexpected error: %v", err)