coder · mtojek · Jun 20, 2023 · May 29, 2023 · Jun 7, 2023 · Jun 7, 2023
diff --git a/cli/clistat/cgroup.go b/cli/clistat/cgroup.go
@@ -0,0 +1,309 @@
+package clistat
+
+import (
+	"bufio"
+	"bytes"
+	"strconv"
+	"strings"
+
+	"github.com/spf13/afero"
+	"golang.org/x/xerrors"
+	"tailscale.com/types/ptr"
+)
+
+// Paths for CGroupV1.
+// Ref: https://www.kernel.org/doc/Documentation/cgroup-v1/cpuacct.txt
+const (
+	// CPU usage of all tasks in cgroup in nanoseconds.
+	cgroupV1CPUAcctUsage = "/sys/fs/cgroup/cpu/cpuacct.usage"
+	// Alternate path
+	cgroupV1CPUAcctUsageAlt = "/sys/fs/cgroup/cpu,cpuacct/cpuacct.usage"
+	// CFS quota and period for cgroup in MICROseconds
+	cgroupV1CFSQuotaUs  = "/sys/fs/cgroup/cpu,cpuacct/cpu.cfs_quota_us"
+	cgroupV1CFSPeriodUs = "/sys/fs/cgroup/cpu,cpuacct/cpu.cfs_period_us"
+	// Maximum memory usable by cgroup in bytes
+	cgroupV1MemoryMaxUsageBytes = "/sys/fs/cgroup/memory/memory.max_usage_in_bytes"
+	// Current memory usage of cgroup in bytes
+	cgroupV1MemoryUsageBytes = "/sys/fs/cgroup/memory/memory.usage_in_bytes"
+	// Other memory stats - we are interested in total_inactive_file
+	cgroupV1MemoryStat = "/sys/fs/cgroup/memory/memory.stat"
+)
+
+// Paths for CGroupV2.
+// Ref: https://docs.kernel.org/admin-guide/cgroup-v2.html
+const (
+	// Contains quota and period in microseconds separated by a space.
+	cgroupV2CPUMax = "/sys/fs/cgroup/cpu.max"
+	// Contains current CPU usage under usage_usec
+	cgroupV2CPUStat = "/sys/fs/cgroup/cpu.stat"
+	// Contains current cgroup memory usage in bytes.
+	cgroupV2MemoryUsageBytes = "/sys/fs/cgroup/memory.current"
+	// Contains max cgroup memory usage in bytes.
+	cgroupV2MemoryMaxBytes = "/sys/fs/cgroup/memory.max"
+	// Other memory stats - we are interested in total_inactive_file
+	cgroupV2MemoryStat = "/sys/fs/cgroup/memory.stat"
+)
+
+// ContainerCPU returns the CPU usage of the container cgroup.
+// This is calculated as difference of two samples of the
+// CPU usage of the container cgroup.
+// The total is read from the relevant path in /sys/fs/cgroup.
+// If there is no limit set, the total is assumed to be the
+// number of host cores multiplied by the CFS period.
+// If the system is not containerized, this always returns nil.
+func (s *Statter) ContainerCPU(m Prefix) (*Result, error) {
+	// Firstly, check if we are containerized.
+	if ok, err := IsContainerized(s.fs); err != nil || !ok {
+		return nil, nil //nolint: nilnil
+	}
+
+	total, err := s.cGroupCPUTotal()
+	if err != nil {
+		return nil, xerrors.Errorf("get total cpu: %w", err)
+	}
+
+	used1, err := s.cGroupCPUUsed()
+	if err != nil {
+		return nil, xerrors.Errorf("get cgroup CPU usage: %w", err)
+	}
+
+	// The measurements in /sys/fs/cgroup are counters.
+	// We need to wait for a bit to get a difference.
+	// Note that someone could reset the counter in the meantime.
+	// We can't do anything about that.
+	s.wait(s.sampleInterval)
+
+	used2, err := s.cGroupCPUUsed()
+	if err != nil {
+		return nil, xerrors.Errorf("get cgroup CPU usage: %w", err)
+	}
+
+	r := &Result{
+		Unit:   "cores",
+		Prefix: m,
+		Used:   (used2 - used1),
+		Total:  ptr.To(total),
+	}
+	return r, nil
+}
+
+func (s *Statter) cGroupCPUTotal() (used float64, err error) {
+	if s.isCGroupV2() {
+		return s.cGroupV2CPUTotal()
+	}
+
+	// Fall back to CGroupv1
+	return s.cGroupV1CPUTotal()
+}
+
+func (s *Statter) cGroupCPUUsed() (used float64, err error) {
+	if s.isCGroupV2() {
+		return s.cGroupV2CPUUsed()
+	}
+
+	return s.cGroupV1CPUUsed()
+}
+
+func (s *Statter) isCGroupV2() bool {
+	// Check for the presence of /sys/fs/cgroup/cpu.max
+	_, err := s.fs.Stat(cgroupV2CPUMax)
+	return err == nil
+}
+
+func (s *Statter) cGroupV2CPUUsed() (used float64, err error) {
+	usageUs, err := readInt64Prefix(s.fs, cgroupV2CPUStat, "usage_usec")
+	if err != nil {
+		return 0, xerrors.Errorf("get cgroupv2 cpu used: %w", err)
+	}
+	periodUs, err := readInt64SepIdx(s.fs, cgroupV2CPUMax, " ", 1)
+	if err != nil {
+		return 0, xerrors.Errorf("get cpu period: %w", err)
+	}
+
+	return float64(usageUs) / float64(periodUs), nil
+}
+
+func (s *Statter) cGroupV2CPUTotal() (total float64, err error) {
+	var quotaUs, periodUs int64
+	periodUs, err = readInt64SepIdx(s.fs, cgroupV2CPUMax, " ", 1)
+	if err != nil {
+		return 0, xerrors.Errorf("get cpu period: %w", err)
+	}
+
+	quotaUs, err = readInt64SepIdx(s.fs, cgroupV2CPUMax, " ", 0)
+	if err != nil {
+		// Fall back to number of cores
+		quotaUs = int64(s.nproc) * periodUs
+	}
+
+	return float64(quotaUs) / float64(periodUs), nil
+}
+
+func (s *Statter) cGroupV1CPUTotal() (float64, error) {
+	periodUs, err := readInt64(s.fs, cgroupV1CFSPeriodUs)
+	if err != nil {
+		return 0, xerrors.Errorf("read cpu period: %w", err)
+	}
+
+	quotaUs, err := readInt64(s.fs, cgroupV1CFSQuotaUs)
+	if err != nil {
+		return 0, xerrors.Errorf("read cpu quota: %w", err)
+	}
+
+	if quotaUs < 0 {
+		// Fall back to the number of cores
+		quotaUs = int64(s.nproc) * periodUs
+	}
+
+	return float64(quotaUs) / float64(periodUs), nil
+}
+
+func (s *Statter) cGroupV1CPUUsed() (float64, error) {
+	usageNs, err := readInt64(s.fs, cgroupV1CPUAcctUsage)
+	if err != nil {
+		// try alternate path
+		usageNs, err = readInt64(s.fs, cgroupV1CPUAcctUsageAlt)
+		if err != nil {
+			return 0, xerrors.Errorf("read cpu used: %w", err)
+		}
+	}
+
+	// usage is in ns, convert to us
+	usageNs /= 1000
+	periodUs, err := readInt64(s.fs, cgroupV1CFSPeriodUs)
+	if err != nil {
+		return 0, xerrors.Errorf("get cpu period: %w", err)
+	}
+
+	return float64(usageNs) / float64(periodUs), nil
+}
+
+// ContainerMemory returns the memory usage of the container cgroup.
+// If the system is not containerized, this always returns nil.
+func (s *Statter) ContainerMemory(m Prefix) (*Result, error) {
+	if ok, err := IsContainerized(s.fs); err != nil || !ok {
+		return nil, nil //nolint:nilnil
+	}
+
+	if s.isCGroupV2() {
+		return s.cGroupV2Memory(m)
+	}
+
+	// Fall back to CGroupv1
+	return s.cGroupV1Memory(m)
+}
+
+func (s *Statter) cGroupV2Memory(m Prefix) (*Result, error) {
+	maxUsageBytes, err := readInt64(s.fs, cgroupV2MemoryMaxBytes)
+	if err != nil {
+		return nil, xerrors.Errorf("read memory total: %w", err)
+	}
+
+	currUsageBytes, err := readInt64(s.fs, cgroupV2MemoryUsageBytes)
+	if err != nil {
+		return nil, xerrors.Errorf("read memory usage: %w", err)
+	}
+
+	inactiveFileBytes, err := readInt64Prefix(s.fs, cgroupV2MemoryStat, "inactive_file")
+	if err != nil {
+		return nil, xerrors.Errorf("read memory stats: %w", err)
+	}
+
+	return &Result{
+		Total:  ptr.To(float64(maxUsageBytes)),
+		Used:   float64(currUsageBytes - inactiveFileBytes),
+		Unit:   "B",
+		Prefix: m,
+	}, nil
+}
+
+func (s *Statter) cGroupV1Memory(m Prefix) (*Result, error) {
+	maxUsageBytes, err := readInt64(s.fs, cgroupV1MemoryMaxUsageBytes)
+	if err != nil {
+		return nil, xerrors.Errorf("read memory total: %w", err)
+	}
+
+	// need a space after total_rss so we don't hit something else
+	usageBytes, err := readInt64(s.fs, cgroupV1MemoryUsageBytes)
+	if err != nil {
+		return nil, xerrors.Errorf("read memory usage: %w", err)
+	}
+
+	totalInactiveFileBytes, err := readInt64Prefix(s.fs, cgroupV1MemoryStat, "total_inactive_file")
+	if err != nil {
+		return nil, xerrors.Errorf("read memory stats: %w", err)
+	}
+
+	// Total memory used is usage - total_inactive_file
+	return &Result{
+		Total:  ptr.To(float64(maxUsageBytes)),
+		Used:   float64(usageBytes - totalInactiveFileBytes),
+		Unit:   "B",
+		Prefix: m,
+	}, nil
+}
+
+// read an int64 value from path
+func readInt64(fs afero.Fs, path string) (int64, error) {
+	data, err := afero.ReadFile(fs, path)
+	if err != nil {
+		return 0, xerrors.Errorf("read %s: %w", path, err)
+	}
+
+	val, err := strconv.ParseInt(string(bytes.TrimSpace(data)), 10, 64)
+	if err != nil {
+		return 0, xerrors.Errorf("parse %s: %w", path, err)
+	}
+
+	return val, nil
+}
+
+// read an int64 value from path at field idx separated by sep
+func readInt64SepIdx(fs afero.Fs, path, sep string, idx int) (int64, error) {
+	data, err := afero.ReadFile(fs, path)
+	if err != nil {
+		return 0, xerrors.Errorf("read %s: %w", path, err)
+	}
+
+	parts := strings.Split(string(data), sep)
+	if len(parts) < idx {
+		return 0, xerrors.Errorf("expected line %q to have at least %d parts", string(data), idx+1)
+	}
+
+	val, err := strconv.ParseInt(strings.TrimSpace(parts[idx]), 10, 64)
+	if err != nil {
+		return 0, xerrors.Errorf("parse %s: %w", path, err)
+	}
+
+	return val, nil
+}
+
+// read the first int64 value from path prefixed with prefix
+func readInt64Prefix(fs afero.Fs, path, prefix string) (int64, error) {
+	data, err := afero.ReadFile(fs, path)
+	if err != nil {
+		return 0, xerrors.Errorf("read %s: %w", path, err)
+	}
+
+	scn := bufio.NewScanner(bytes.NewReader(data))
+	for scn.Scan() {
+		line := scn.Text()
+		if !strings.HasPrefix(line, prefix) {
+			continue
+		}
+
+		parts := strings.Fields(line)
+		if len(parts) != 2 {
+			return 0, xerrors.Errorf("parse %s: expected two fields but got %s", path, line)
+		}
+
+		val, err := strconv.ParseInt(strings.TrimSpace(parts[1]), 10, 64)
+		if err != nil {
+			return 0, xerrors.Errorf("parse %s: %w", path, err)
+		}
+
+		return val, nil
+	}
+
+	return 0, xerrors.Errorf("parse %s: did not find line with prefix %s", path, prefix)
+}
diff --git a/cli/clistat/container.go b/cli/clistat/container.go
@@ -0,0 +1,61 @@
+package clistat
+
+import (
+	"bufio"
+	"bytes"
+	"os"
+
+	"github.com/spf13/afero"
+	"golang.org/x/xerrors"
+)
+
+const (
+	procMounts    = "/proc/mounts"
+	procOneCgroup = "/proc/1/cgroup"
+)
+
+// IsContainerized returns whether the host is containerized.
+// This is adapted from https://github.com/elastic/go-sysinfo/tree/main/providers/linux/container.go#L31
+// with modifications to support Sysbox containers.
+// On non-Linux platforms, it always returns false.
+func IsContainerized(fs afero.Fs) (ok bool, err error) {
+	cgData, err := afero.ReadFile(fs, procOneCgroup)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, nil // how?
+		}
+		return false, xerrors.Errorf("read file %s: %w", procOneCgroup, err)
+	}
+
+	scn := bufio.NewScanner(bytes.NewReader(cgData))
+	for scn.Scan() {
+		line := scn.Bytes()
+		if bytes.Contains(line, []byte("docker")) ||
+			bytes.Contains(line, []byte(".slice")) ||
+			bytes.Contains(line, []byte("lxc")) ||
+			bytes.Contains(line, []byte("kubepods")) {
+			return true, nil
+		}
+	}
+
+	// Last-ditch effort to detect Sysbox containers.
+	// Check if we have anything mounted as type sysboxfs in /proc/mounts
+	mountsData, err := afero.ReadFile(fs, procMounts)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return false, nil // how??
+		}
+		return false, xerrors.Errorf("read file %s: %w", procMounts, err)
+	}
+
+	scn = bufio.NewScanner(bytes.NewReader(mountsData))
+	for scn.Scan() {
+		line := scn.Bytes()
+		if bytes.Contains(line, []byte("sysboxfs")) {
+			return true, nil
+		}
+	}
+
+	// If we get here, we are _probably_ not running in a container.
+	return false, nil
+}
diff --git a/cli/clistat/disk.go b/cli/clistat/disk.go
@@ -0,0 +1,27 @@
+//go:build !windows
+
+package clistat
+
+import (
+	"syscall"
+
+	"tailscale.com/types/ptr"
+)
+
+// Disk returns the disk usage of the given path.
+// If path is empty, it returns the usage of the root directory.
+func (*Statter) Disk(path string, m Prefix) (*Result, error) {
+	if path == "" {
+		path = "/"
+	}
+	var stat syscall.Statfs_t
+	if err := syscall.Statfs(path, &stat); err != nil {
+		return nil, err
+	}
+	var r Result
+	r.Total = ptr.To(float64(stat.Blocks * uint64(stat.Bsize)))
+	r.Used = float64(stat.Blocks-stat.Bfree) * float64(stat.Bsize)
+	r.Unit = "B"
+	r.Prefix = m
+	return &r, nil
+}