libct/cg: mv fscommon.{Open,Read,Write}File to cgroups

This is a better place as cgroups itself is using these. Should help with moving more stuff common in between fs and fs2 to fscommon. Looks big, but this is just moving the code around: fscommon/{fscommon,open}.go -> cgroups/file.go fscommon/fscommon_test.go -> cgroups/file_test.go There's no functional change. Signed-off-by: Kir Kolyshkin <[email protected]>
opencontainers · Jun 11, 2021 · 98a8545 · 98a8545
1 parent 93a01cd
commit 98a8545
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Showing 26 changed files with 136 additions and 146 deletions.
diff --git a/libcontainer/cgroups/fscommon/open.go → libcontainer/cgroups/file.go b/libcontainer/cgroups/fscommon/open.go → libcontainer/cgroups/file.go
@@ -1,6 +1,7 @@
-package fscommon
+package cgroups
 
 import (
+	"bytes"
 	"os"
 	"strings"
 	"sync"
@@ -10,6 +11,54 @@ import (
 	"golang.org/x/sys/unix"
 )
 
+// OpenFile opens a cgroup file in a given dir with given flags.
+// It is supposed to be used for cgroup files only.
+func OpenFile(dir, file string, flags int) (*os.File, error) {
+	if dir == "" {
+		return nil, errors.Errorf("no directory specified for %s", file)
+	}
+	return openFile(dir, file, flags)
+}
+
+// ReadFile reads data from a cgroup file in dir.
+// It is supposed to be used for cgroup files only.
+func ReadFile(dir, file string) (string, error) {
+	fd, err := OpenFile(dir, file, unix.O_RDONLY)
+	if err != nil {
+		return "", err
+	}
+	defer fd.Close()
+	var buf bytes.Buffer
+
+	_, err = buf.ReadFrom(fd)
+	return buf.String(), err
+}
+
+// WriteFile writes data to a cgroup file in dir.
+// It is supposed to be used for cgroup files only.
+func WriteFile(dir, file, data string) error {
+	fd, err := OpenFile(dir, file, unix.O_WRONLY)
+	if err != nil {
+		return err
+	}
+	defer fd.Close()
+	if err := retryingWriteFile(fd, data); err != nil {
+		return errors.Wrapf(err, "failed to write %q", data)
+	}
+	return nil
+}
+
+func retryingWriteFile(fd *os.File, data string) error {
+	for {
+		_, err := fd.Write([]byte(data))
+		if errors.Is(err, unix.EINTR) {
+			logrus.Infof("interrupted while writing %s to %s", data, fd.Name())
+			continue
+		}
+		return err
+	}
+}
+
 const (
 	cgroupfsDir    = "/sys/fs/cgroup"
 	cgroupfsPrefix = cgroupfsDir + "/"
@@ -60,10 +109,7 @@ func prepareOpenat2() error {
 
 // OpenFile opens a cgroup file in a given dir with given flags.
 // It is supposed to be used for cgroup files only.
-func OpenFile(dir, file string, flags int) (*os.File, error) {
-	if dir == "" {
-		return nil, errors.Errorf("no directory specified for %s", file)
-	}
+func openFile(dir, file string, flags int) (*os.File, error) {
 	mode := os.FileMode(0)
 	if TestMode && flags&os.O_WRONLY != 0 {
 		// "emulate" cgroup fs for unit tests

diff --git a/...ntainer/cgroups/fscommon/fscommon_test.go → libcontainer/cgroups/file_test.go b/...ntainer/cgroups/fscommon/fscommon_test.go → libcontainer/cgroups/file_test.go
@@ -1,6 +1,6 @@
 // +build linux
 
-package fscommon
+package cgroups
 
 import (
 	"fmt"

diff --git a/libcontainer/cgroups/fs/blkio.go b/libcontainer/cgroups/fs/blkio.go
@@ -11,7 +11,6 @@ import (
 	"strings"
 
 	"github.com/opencontainers/runc/libcontainer/cgroups"
-	"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
 	"github.com/opencontainers/runc/libcontainer/configs"
 )
 
@@ -31,41 +30,41 @@ func (s *BlkioGroup) Apply(path string, d *cgroupData) error {
 func (s *BlkioGroup) Set(path string, r *configs.Resources) error {
 	s.detectWeightFilenames(path)
 	if r.BlkioWeight != 0 {
-		if err := fscommon.WriteFile(path, s.weightFilename, strconv.FormatUint(uint64(r.BlkioWeight), 10)); err != nil {
+		if err := cgroups.WriteFile(path, s.weightFilename, strconv.FormatUint(uint64(r.BlkioWeight), 10)); err != nil {
 			return err
 		}
 	}
 
 	if r.BlkioLeafWeight != 0 {
-		if err := fscommon.WriteFile(path, "blkio.leaf_weight", strconv.FormatUint(uint64(r.BlkioLeafWeight), 10)); err != nil {
+		if err := cgroups.WriteFile(path, "blkio.leaf_weight", strconv.FormatUint(uint64(r.BlkioLeafWeight), 10)); err != nil {
 			return err
 		}
 	}
 	for _, wd := range r.BlkioWeightDevice {
-		if err := fscommon.WriteFile(path, s.weightDeviceFilename, wd.WeightString()); err != nil {
+		if err := cgroups.WriteFile(path, s.weightDeviceFilename, wd.WeightString()); err != nil {
 			return err
 		}
-		if err := fscommon.WriteFile(path, "blkio.leaf_weight_device", wd.LeafWeightString()); err != nil {
+		if err := cgroups.WriteFile(path, "blkio.leaf_weight_device", wd.LeafWeightString()); err != nil {
 			return err
 		}
 	}
 	for _, td := range r.BlkioThrottleReadBpsDevice {
-		if err := fscommon.WriteFile(path, "blkio.throttle.read_bps_device", td.String()); err != nil {
+		if err := cgroups.WriteFile(path, "blkio.throttle.read_bps_device", td.String()); err != nil {
 			return err
 		}
 	}
 	for _, td := range r.BlkioThrottleWriteBpsDevice {
-		if err := fscommon.WriteFile(path, "blkio.throttle.write_bps_device", td.String()); err != nil {
+		if err := cgroups.WriteFile(path, "blkio.throttle.write_bps_device", td.String()); err != nil {
 			return err
 		}
 	}
 	for _, td := range r.BlkioThrottleReadIOPSDevice {
-		if err := fscommon.WriteFile(path, "blkio.throttle.read_iops_device", td.String()); err != nil {
+		if err := cgroups.WriteFile(path, "blkio.throttle.read_iops_device", td.String()); err != nil {
 			return err
 		}
 	}
 	for _, td := range r.BlkioThrottleWriteIOPSDevice {
-		if err := fscommon.WriteFile(path, "blkio.throttle.write_iops_device", td.String()); err != nil {
+		if err := cgroups.WriteFile(path, "blkio.throttle.write_iops_device", td.String()); err != nil {
 			return err
 		}
 	}
@@ -110,7 +109,7 @@ func splitBlkioStatLine(r rune) bool {
 
 func getBlkioStat(dir, file string) ([]cgroups.BlkioStatEntry, error) {
 	var blkioStats []cgroups.BlkioStatEntry
-	f, err := fscommon.OpenFile(dir, file, os.O_RDONLY)
+	f, err := cgroups.OpenFile(dir, file, os.O_RDONLY)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return blkioStats, nil

diff --git a/libcontainer/cgroups/fs/cpu.go b/libcontainer/cgroups/fs/cpu.go
@@ -41,12 +41,12 @@ func (s *CpuGroup) Apply(path string, d *cgroupData) error {
 
 func (s *CpuGroup) SetRtSched(path string, r *configs.Resources) error {
 	if r.CpuRtPeriod != 0 {
-		if err := fscommon.WriteFile(path, "cpu.rt_period_us", strconv.FormatUint(r.CpuRtPeriod, 10)); err != nil {
+		if err := cgroups.WriteFile(path, "cpu.rt_period_us", strconv.FormatUint(r.CpuRtPeriod, 10)); err != nil {
 			return err
 		}
 	}
 	if r.CpuRtRuntime != 0 {
-		if err := fscommon.WriteFile(path, "cpu.rt_runtime_us", strconv.FormatInt(r.CpuRtRuntime, 10)); err != nil {
+		if err := cgroups.WriteFile(path, "cpu.rt_runtime_us", strconv.FormatInt(r.CpuRtRuntime, 10)); err != nil {
 			return err
 		}
 	}
@@ -56,7 +56,7 @@ func (s *CpuGroup) SetRtSched(path string, r *configs.Resources) error {
 func (s *CpuGroup) Set(path string, r *configs.Resources) error {
 	if r.CpuShares != 0 {
 		shares := r.CpuShares
-		if err := fscommon.WriteFile(path, "cpu.shares", strconv.FormatUint(shares, 10)); err != nil {
+		if err := cgroups.WriteFile(path, "cpu.shares", strconv.FormatUint(shares, 10)); err != nil {
 			return err
 		}
 		// read it back
@@ -72,20 +72,20 @@ func (s *CpuGroup) Set(path string, r *configs.Resources) error {
 		}
 	}
 	if r.CpuPeriod != 0 {
-		if err := fscommon.WriteFile(path, "cpu.cfs_period_us", strconv.FormatUint(r.CpuPeriod, 10)); err != nil {
+		if err := cgroups.WriteFile(path, "cpu.cfs_period_us", strconv.FormatUint(r.CpuPeriod, 10)); err != nil {
 			return err
 		}
 	}
 	if r.CpuQuota != 0 {
-		if err := fscommon.WriteFile(path, "cpu.cfs_quota_us", strconv.FormatInt(r.CpuQuota, 10)); err != nil {
+		if err := cgroups.WriteFile(path, "cpu.cfs_quota_us", strconv.FormatInt(r.CpuQuota, 10)); err != nil {
 			return err
 		}
 	}
 	return s.SetRtSched(path, r)
 }
 
 func (s *CpuGroup) GetStats(path string, stats *cgroups.Stats) error {
-	f, err := fscommon.OpenFile(path, "cpu.stat", os.O_RDONLY)
+	f, err := cgroups.OpenFile(path, "cpu.stat", os.O_RDONLY)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return nil

diff --git a/libcontainer/cgroups/fs/cpuacct.go b/libcontainer/cgroups/fs/cpuacct.go
@@ -90,7 +90,7 @@ func getCpuUsageBreakdown(path string) (uint64, uint64, error) {
 	// Expected format:
 	// user <usage in ticks>
 	// system <usage in ticks>
-	data, err := fscommon.ReadFile(path, cgroupCpuacctStat)
+	data, err := cgroups.ReadFile(path, cgroupCpuacctStat)
 	if err != nil {
 		return 0, 0, err
 	}
@@ -116,7 +116,7 @@ func getCpuUsageBreakdown(path string) (uint64, uint64, error) {
 
 func getPercpuUsage(path string) ([]uint64, error) {
 	percpuUsage := []uint64{}
-	data, err := fscommon.ReadFile(path, "cpuacct.usage_percpu")
+	data, err := cgroups.ReadFile(path, "cpuacct.usage_percpu")
 	if err != nil {
 		return percpuUsage, err
 	}
@@ -134,7 +134,7 @@ func getPercpuUsageInModes(path string) ([]uint64, []uint64, error) {
 	usageKernelMode := []uint64{}
 	usageUserMode := []uint64{}
 
-	file, err := fscommon.OpenFile(path, cgroupCpuacctUsageAll, os.O_RDONLY)
+	file, err := cgroups.OpenFile(path, cgroupCpuacctUsageAll, os.O_RDONLY)
 	if os.IsNotExist(err) {
 		return usageKernelMode, usageUserMode, nil
 	} else if err != nil {

diff --git a/libcontainer/cgroups/fs/cpuset.go b/libcontainer/cgroups/fs/cpuset.go
@@ -28,12 +28,12 @@ func (s *CpusetGroup) Apply(path string, d *cgroupData) error {
 
 func (s *CpusetGroup) Set(path string, r *configs.Resources) error {
 	if r.CpusetCpus != "" {
-		if err := fscommon.WriteFile(path, "cpuset.cpus", r.CpusetCpus); err != nil {
+		if err := cgroups.WriteFile(path, "cpuset.cpus", r.CpusetCpus); err != nil {
 			return err
 		}
 	}
 	if r.CpusetMems != "" {
-		if err := fscommon.WriteFile(path, "cpuset.mems", r.CpusetMems); err != nil {
+		if err := cgroups.WriteFile(path, "cpuset.mems", r.CpusetMems); err != nil {
 			return err
 		}
 	}
@@ -175,10 +175,10 @@ func (s *CpusetGroup) ApplyDir(dir string, r *configs.Resources, pid int) error
 }
 
 func getCpusetSubsystemSettings(parent string) (cpus, mems string, err error) {
-	if cpus, err = fscommon.ReadFile(parent, "cpuset.cpus"); err != nil {
+	if cpus, err = cgroups.ReadFile(parent, "cpuset.cpus"); err != nil {
 		return
 	}
-	if mems, err = fscommon.ReadFile(parent, "cpuset.mems"); err != nil {
+	if mems, err = cgroups.ReadFile(parent, "cpuset.mems"); err != nil {
 		return
 	}
 	return cpus, mems, nil
@@ -224,12 +224,12 @@ func cpusetCopyIfNeeded(current, parent string) error {
 	}
 
 	if isEmptyCpuset(currentCpus) {
-		if err := fscommon.WriteFile(current, "cpuset.cpus", string(parentCpus)); err != nil {
+		if err := cgroups.WriteFile(current, "cpuset.cpus", string(parentCpus)); err != nil {
 			return err
 		}
 	}
 	if isEmptyCpuset(currentMems) {
-		if err := fscommon.WriteFile(current, "cpuset.mems", string(parentMems)); err != nil {
+		if err := cgroups.WriteFile(current, "cpuset.mems", string(parentMems)); err != nil {
 			return err
 		}
 	}

diff --git a/libcontainer/cgroups/fs/devices.go b/libcontainer/cgroups/fs/devices.go
@@ -9,7 +9,6 @@ import (
 
 	"github.com/opencontainers/runc/libcontainer/cgroups"
 	cgroupdevices "github.com/opencontainers/runc/libcontainer/cgroups/devices"
-	"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
 	"github.com/opencontainers/runc/libcontainer/configs"
 	"github.com/opencontainers/runc/libcontainer/devices"
 	"github.com/opencontainers/runc/libcontainer/userns"
@@ -36,7 +35,7 @@ func (s *DevicesGroup) Apply(path string, d *cgroupData) error {
 }
 
 func loadEmulator(path string) (*cgroupdevices.Emulator, error) {
-	list, err := fscommon.ReadFile(path, "devices.list")
+	list, err := cgroups.ReadFile(path, "devices.list")
 	if err != nil {
 		return nil, err
 	}
@@ -81,7 +80,7 @@ func (s *DevicesGroup) Set(path string, r *configs.Resources) error {
 		if rule.Allow {
 			file = "devices.allow"
 		}
-		if err := fscommon.WriteFile(path, file, rule.CgroupString()); err != nil {
+		if err := cgroups.WriteFile(path, file, rule.CgroupString()); err != nil {
 			return err
 		}
 	}

diff --git a/libcontainer/cgroups/fs/freezer.go b/libcontainer/cgroups/fs/freezer.go
@@ -10,7 +10,6 @@ import (
 	"time"
 
 	"github.com/opencontainers/runc/libcontainer/cgroups"
-	"github.com/opencontainers/runc/libcontainer/cgroups/fscommon"
 	"github.com/opencontainers/runc/libcontainer/configs"
 	"github.com/sirupsen/logrus"
 	"golang.org/x/sys/unix"
@@ -34,7 +33,7 @@ func (s *FreezerGroup) Set(path string, r *configs.Resources) (Err error) {
 				// Freezing failed, and it is bad and dangerous
 				// to leave the cgroup in FROZEN or FREEZING
 				// state, so (try to) thaw it back.
-				_ = fscommon.WriteFile(path, "freezer.state", string(configs.Thawed))
+				_ = cgroups.WriteFile(path, "freezer.state", string(configs.Thawed))
 			}
 		}()
 
@@ -67,11 +66,11 @@ func (s *FreezerGroup) Set(path string, r *configs.Resources) (Err error) {
 				// the chances to succeed in freezing
 				// in case new processes keep appearing
 				// in the cgroup.
-				_ = fscommon.WriteFile(path, "freezer.state", string(configs.Thawed))
+				_ = cgroups.WriteFile(path, "freezer.state", string(configs.Thawed))
 				time.Sleep(10 * time.Millisecond)
 			}
 
-			if err := fscommon.WriteFile(path, "freezer.state", string(configs.Frozen)); err != nil {
+			if err := cgroups.WriteFile(path, "freezer.state", string(configs.Frozen)); err != nil {
 				return err
 			}
 
@@ -82,7 +81,7 @@ func (s *FreezerGroup) Set(path string, r *configs.Resources) (Err error) {
 				// system.
 				time.Sleep(10 * time.Microsecond)
 			}
-			state, err := fscommon.ReadFile(path, "freezer.state")
+			state, err := cgroups.ReadFile(path, "freezer.state")
 			if err != nil {
 				return err
 			}
@@ -103,7 +102,7 @@ func (s *FreezerGroup) Set(path string, r *configs.Resources) (Err error) {
 		// Despite our best efforts, it got stuck in FREEZING.
 		return errors.New("unable to freeze")
 	case configs.Thawed:
-		return fscommon.WriteFile(path, "freezer.state", string(configs.Thawed))
+		return cgroups.WriteFile(path, "freezer.state", string(configs.Thawed))
 	case configs.Undefined:
 		return nil
 	default:
@@ -117,7 +116,7 @@ func (s *FreezerGroup) GetStats(path string, stats *cgroups.Stats) error {
 
 func (s *FreezerGroup) GetState(path string) (configs.FreezerState, error) {
 	for {
-		state, err := fscommon.ReadFile(path, "freezer.state")
+		state, err := cgroups.ReadFile(path, "freezer.state")
 		if err != nil {
 			// If the kernel is too old, then we just treat the freezer as
 			// being in an "undefined" state.

diff --git a/libcontainer/cgroups/fs/hugetlb.go b/libcontainer/cgroups/fs/hugetlb.go
@@ -23,7 +23,7 @@ func (s *HugetlbGroup) Apply(path string, d *cgroupData) error {
 
 func (s *HugetlbGroup) Set(path string, r *configs.Resources) error {
 	for _, hugetlb := range r.HugetlbLimit {
-		if err := fscommon.WriteFile(path, "hugetlb."+hugetlb.Pagesize+".limit_in_bytes", strconv.FormatUint(hugetlb.Limit, 10)); err != nil {
+		if err := cgroups.WriteFile(path, "hugetlb."+hugetlb.Pagesize+".limit_in_bytes", strconv.FormatUint(hugetlb.Limit, 10)); err != nil {
 			return err
 		}
 	}