github.com/containerd/Containerd@v1.4.13/sys/socket_unix.go (about)

     1  // +build !windows
     2  
     3  /*
     4     Copyright The containerd Authors.
     5  
     6     Licensed under the Apache License, Version 2.0 (the "License");
     7     you may not use this file except in compliance with the License.
     8     You may obtain a copy of the License at
     9  
    10         http://www.apache.org/licenses/LICENSE-2.0
    11  
    12     Unless required by applicable law or agreed to in writing, software
    13     distributed under the License is distributed on an "AS IS" BASIS,
    14     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    15     See the License for the specific language governing permissions and
    16     limitations under the License.
    17  */
    18  
    19  package sys
    20  
    21  import (
    22  	"net"
    23  	"os"
    24  	"path/filepath"
    25  
    26  	"github.com/pkg/errors"
    27  	"golang.org/x/sys/unix"
    28  )
    29  
    30  // CreateUnixSocket creates a unix socket and returns the listener
    31  func CreateUnixSocket(path string) (net.Listener, error) {
    32  	// BSDs have a 104 limit
    33  	if len(path) > 104 {
    34  		return nil, errors.Errorf("%q: unix socket path too long (> 104)", path)
    35  	}
    36  	if err := os.MkdirAll(filepath.Dir(path), 0660); err != nil {
    37  		return nil, err
    38  	}
    39  	if err := unix.Unlink(path); err != nil && !os.IsNotExist(err) {
    40  		return nil, err
    41  	}
    42  	return net.Listen("unix", path)
    43  }
    44  
    45  // GetLocalListener returns a listener out of a unix socket.
    46  func GetLocalListener(path string, uid, gid int) (net.Listener, error) {
    47  	// Ensure parent directory is created
    48  	if err := mkdirAs(filepath.Dir(path), uid, gid); err != nil {
    49  		return nil, err
    50  	}
    51  
    52  	l, err := CreateUnixSocket(path)
    53  	if err != nil {
    54  		return l, err
    55  	}
    56  
    57  	if err := os.Chmod(path, 0660); err != nil {
    58  		l.Close()
    59  		return nil, err
    60  	}
    61  
    62  	if err := os.Chown(path, uid, gid); err != nil {
    63  		l.Close()
    64  		return nil, err
    65  	}
    66  
    67  	return l, nil
    68  }
    69  
    70  func mkdirAs(path string, uid, gid int) error {
    71  	if _, err := os.Stat(path); !os.IsNotExist(err) {
    72  		return err
    73  	}
    74  
    75  	if err := os.MkdirAll(path, 0770); err != nil {
    76  		return err
    77  	}
    78  
    79  	return os.Chown(path, uid, gid)
    80  }