github.com/hellobchain/third_party@v0.0.0-20230331131523-deb0478a2e52/prometheus/procfs/proc_ns.go (about)

     1  // Copyright 2018 The Prometheus Authors
     2  // Licensed under the Apache License, Version 2.0 (the "License");
     3  // you may not use this file except in compliance with the License.
     4  // You may obtain a copy of the License at
     5  //
     6  // http://www.apache.org/licenses/LICENSE-2.0
     7  //
     8  // Unless required by applicable law or agreed to in writing, software
     9  // distributed under the License is distributed on an "AS IS" BASIS,
    10  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    11  // See the License for the specific language governing permissions and
    12  // limitations under the License.
    13  
    14  package procfs
    15  
    16  import (
    17  	"fmt"
    18  	"os"
    19  	"strconv"
    20  	"strings"
    21  )
    22  
    23  // Namespace represents a single namespace of a process.
    24  type Namespace struct {
    25  	Type  string // Namespace type.
    26  	Inode uint32 // Inode number of the namespace. If two processes are in the same namespace their inodes will match.
    27  }
    28  
    29  // Namespaces contains all of the namespaces that the process is contained in.
    30  type Namespaces map[string]Namespace
    31  
    32  // NewNamespaces reads from /proc/[pid/ns/* to get the namespaces of which the
    33  // process is a member.
    34  func (p Proc) NewNamespaces() (Namespaces, error) {
    35  	d, err := os.Open(p.path("ns"))
    36  	if err != nil {
    37  		return nil, err
    38  	}
    39  	defer d.Close()
    40  
    41  	names, err := d.Readdirnames(-1)
    42  	if err != nil {
    43  		return nil, fmt.Errorf("failed to read contents of ns dir: %v", err)
    44  	}
    45  
    46  	ns := make(Namespaces, len(names))
    47  	for _, name := range names {
    48  		target, err := os.Readlink(p.path("ns", name))
    49  		if err != nil {
    50  			return nil, err
    51  		}
    52  
    53  		fields := strings.SplitN(target, ":", 2)
    54  		if len(fields) != 2 {
    55  			return nil, fmt.Errorf("failed to parse namespace type and inode from '%v'", target)
    56  		}
    57  
    58  		typ := fields[0]
    59  		inode, err := strconv.ParseUint(strings.Trim(fields[1], "[]"), 10, 32)
    60  		if err != nil {
    61  			return nil, fmt.Errorf("failed to parse inode from '%v': %v", fields[1], err)
    62  		}
    63  
    64  		ns[name] = Namespace{typ, uint32(inode)}
    65  	}
    66  
    67  	return ns, nil
    68  }