cubefs

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// Copyright 2019 The Prometheus Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package fs
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import (
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	"fmt"
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	"os"
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	"path/filepath"
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)
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const (
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	// DefaultProcMountPoint is the common mount point of the proc filesystem.
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	DefaultProcMountPoint = "/proc"
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	// DefaultSysMountPoint is the common mount point of the sys filesystem.
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	DefaultSysMountPoint = "/sys"
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	// DefaultConfigfsMountPoint is the common mount point of the configfs.
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	DefaultConfigfsMountPoint = "/sys/kernel/config"
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)
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// FS represents a pseudo-filesystem, normally /proc or /sys, which provides an
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// interface to kernel data structures.
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type FS string
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// NewFS returns a new FS mounted under the given mountPoint. It will error
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// if the mount point can't be read.
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func NewFS(mountPoint string) (FS, error) {
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	info, err := os.Stat(mountPoint)
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	if err != nil {
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		return "", fmt.Errorf("could not read %q: %w", mountPoint, err)
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	}
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	if !info.IsDir() {
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		return "", fmt.Errorf("mount point %q is not a directory", mountPoint)
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	}
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	return FS(mountPoint), nil
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}
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// Path appends the given path elements to the filesystem path, adding separators
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// as necessary.
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func (fs FS) Path(p ...string) string {
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	return filepath.Join(append([]string{string(fs)}, p...)...)
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}
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