clair/vendor/github.com/prometheus/procfs/sysfs/fs.go
2017-05-05 11:46:41 -04:00

83 lines
2.3 KiB
Go

// Copyright 2017 The Prometheus Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package sysfs
import (
"fmt"
"os"
"path/filepath"
"github.com/prometheus/procfs/xfs"
)
// FS represents the pseudo-filesystem sys, which provides an interface to
// kernel data structures.
type FS string
// DefaultMountPoint is the common mount point of the sys filesystem.
const DefaultMountPoint = "/sys"
// NewFS returns a new FS mounted under the given mountPoint. It will error
// if the mount point can't be read.
func NewFS(mountPoint string) (FS, error) {
info, err := os.Stat(mountPoint)
if err != nil {
return "", fmt.Errorf("could not read %s: %s", mountPoint, err)
}
if !info.IsDir() {
return "", fmt.Errorf("mount point %s is not a directory", mountPoint)
}
return FS(mountPoint), nil
}
// Path returns the path of the given subsystem relative to the sys root.
func (fs FS) Path(p ...string) string {
return filepath.Join(append([]string{string(fs)}, p...)...)
}
// XFSStats retrieves XFS filesystem runtime statistics for each mounted XFS
// filesystem. Only available on kernel 4.4+. On older kernels, an empty
// slice of *xfs.Stats will be returned.
func (fs FS) XFSStats() ([]*xfs.Stats, error) {
matches, err := filepath.Glob(fs.Path("fs/xfs/*/stats/stats"))
if err != nil {
return nil, err
}
stats := make([]*xfs.Stats, 0, len(matches))
for _, m := range matches {
f, err := os.Open(m)
if err != nil {
return nil, err
}
// "*" used in glob above indicates the name of the filesystem.
name := filepath.Base(filepath.Dir(filepath.Dir(m)))
// File must be closed after parsing, regardless of success or
// failure. Defer is not used because of the loop.
s, err := xfs.ParseStats(f)
_ = f.Close()
if err != nil {
return nil, err
}
s.Name = name
stats = append(stats, s)
}
return stats, nil
}