1 files changed, 151 insertions, 0 deletions
diff --git a/vendor/go.uber.org/automaxprocs/internal/cgroups/cgroups2.go b/vendor/go.uber.org/automaxprocs/internal/cgroups/cgroups2.go
new file mode 100644
index 000000000..66930d0ac
--- /dev/null
+++ b/vendor/go.uber.org/automaxprocs/internal/cgroups/cgroups2.go
@@ -0,0 +1,151 @@
+// Copyright (c) 2022 Uber Technologies, Inc.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to deal
+// in the Software without restriction, including without limitation the rights
+// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+// copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+// THE SOFTWARE.
+
+//go:build linux
+// +build linux
+
+package cgroups
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+)
+
+const (
+	// _cgroupv2CPUMax is the file name for the CGroup-V2 CPU max and period
+	// parameter.
+	_cgroupv2CPUMax = "cpu.max"
+	// _cgroupFSType is the Linux CGroup-V2 file system type used in
+	// `/proc/$PID/mountinfo`.
+	_cgroupv2FSType = "cgroup2"
+
+	_cgroupv2MountPoint = "/sys/fs/cgroup"
+
+	_cgroupV2CPUMaxDefaultPeriod = 100000
+	_cgroupV2CPUMaxQuotaMax      = "max"
+)
+
+const (
+	_cgroupv2CPUMaxQuotaIndex = iota
+	_cgroupv2CPUMaxPeriodIndex
+)
+
+// ErrNotV2 indicates that the system is not using cgroups2.
+var ErrNotV2 = errors.New("not using cgroups2")
+
+// CGroups2 provides access to cgroups data for systems using cgroups2.
+type CGroups2 struct {
+	mountPoint string
+	cpuMaxFile string
+}
+
+// NewCGroups2ForCurrentProcess builds a CGroups2 for the current process.
+//
+// This returns ErrNotV2 if the system is not using cgroups2.
+func NewCGroups2ForCurrentProcess() (*CGroups2, error) {
+	return newCGroups2FromMountInfo(_procPathMountInfo)
+}
+
+func newCGroups2FromMountInfo(mountInfoPath string) (*CGroups2, error) {
+	isV2, err := isCGroupV2(mountInfoPath)
+	if err != nil {
+		return nil, err
+	}
+
+	if !isV2 {
+		return nil, ErrNotV2
+	}
+
+	return &CGroups2{
+		mountPoint: _cgroupv2MountPoint,
+		cpuMaxFile: _cgroupv2CPUMax,
+	}, nil
+}
+
+func isCGroupV2(procPathMountInfo string) (bool, error) {
+	var (
+		isV2          bool
+		newMountPoint = func(mp *MountPoint) error {
+			isV2 = isV2 || (mp.FSType == _cgroupv2FSType && mp.MountPoint == _cgroupv2MountPoint)
+			return nil
+		}
+	)
+
+	if err := parseMountInfo(procPathMountInfo, newMountPoint); err != nil {
+		return false, err
+	}
+
+	return isV2, nil
+}
+
+// CPUQuota returns the CPU quota applied with the CPU cgroup2 controller.
+// It is a result of reading cpu quota and period from cpu.max file.
+// It will return `cpu.max / cpu.period`. If cpu.max is set to max, it returns
+// (-1, false, nil)
+func (cg *CGroups2) CPUQuota() (float64, bool, error) {
+	cpuMaxParams, err := os.Open(path.Join(cg.mountPoint, cg.cpuMaxFile))
+	if err != nil {
+		if os.IsNotExist(err) {
+			return -1, false, nil
+		}
+		return -1, false, err
+	}
+
+	scanner := bufio.NewScanner(cpuMaxParams)
+	if scanner.Scan() {
+		fields := strings.Fields(scanner.Text())
+		if len(fields) == 0 || len(fields) > 2 {
+			return -1, false, fmt.Errorf("invalid format")
+		}
+
+		if fields[_cgroupv2CPUMaxQuotaIndex] == _cgroupV2CPUMaxQuotaMax {
+			return -1, false, nil
+		}
+
+		max, err := strconv.Atoi(fields[_cgroupv2CPUMaxQuotaIndex])
+		if err != nil {
+			return -1, false, err
+		}
+
+		var period int
+		if len(fields) == 1 {
+			period = _cgroupV2CPUMaxDefaultPeriod
+		} else {
+			period, err = strconv.Atoi(fields[_cgroupv2CPUMaxPeriodIndex])
+			if err != nil {
+				return -1, false, err
+			}
+		}
+
+		return float64(max) / float64(period), true, nil
+	}
+
+	if err := scanner.Err(); err != nil {
+		return -1, false, err
+	}
+
+	return 0, false, io.ErrUnexpectedEOF
+}