Andrew's git - gitweb.git/blob - contrib/persistent-https/socket.go

   1// Copyright 2012 Google Inc. All Rights Reserved.
   2//
   3// Licensed under the Apache License, Version 2.0 (the "License");
   4// you may not use this file except in compliance with the License.
   5// You may obtain a copy of the License at
   6//
   7//     http://www.apache.org/licenses/LICENSE-2.0
   8//
   9// Unless required by applicable law or agreed to in writing, software
  10// distributed under the License is distributed on an "AS IS" BASIS,
  11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  12// See the License for the specific language governing permissions and
  13// limitations under the License.
  14
  15package main
  16
  17import (
  18        "fmt"
  19        "log"
  20        "net"
  21        "os"
  22        "path/filepath"
  23        "syscall"
  24)
  25
  26// A Socket is a wrapper around a Unix socket that verifies directory
  27// permissions.
  28type Socket struct {
  29        Dir string
  30}
  31
  32func defaultDir() string {
  33        sockPath := ".git-credential-cache"
  34        if home := os.Getenv("HOME"); home != "" {
  35                return filepath.Join(home, sockPath)
  36        }
  37        log.Printf("socket: cannot find HOME path. using relative directory %q for socket", sockPath)
  38        return sockPath
  39}
  40
  41// DefaultSocket is a Socket in the $HOME/.git-credential-cache directory.
  42var DefaultSocket = Socket{Dir: defaultDir()}
  43
  44// Listen announces the local network address of the unix socket. The
  45// permissions on the socket directory are verified before attempting
  46// the actual listen.
  47func (s Socket) Listen() (net.Listener, error) {
  48        network, addr := "unix", s.Path()
  49        if err := s.mkdir(); err != nil {
  50                return nil, &net.OpError{Op: "listen", Net: network, Addr: &net.UnixAddr{Name: addr, Net: network}, Err: err}
  51        }
  52        return net.Listen(network, addr)
  53}
  54
  55// Dial connects to the unix socket. The permissions on the socket directory
  56// are verified before attempting the actual dial.
  57func (s Socket) Dial() (net.Conn, error) {
  58        network, addr := "unix", s.Path()
  59        if err := s.checkPermissions(); err != nil {
  60                return nil, &net.OpError{Op: "dial", Net: network, Addr: &net.UnixAddr{Name: addr, Net: network}, Err: err}
  61        }
  62        return net.Dial(network, addr)
  63}
  64
  65// Path returns the fully specified file name of the unix socket.
  66func (s Socket) Path() string {
  67        return filepath.Join(s.Dir, "persistent-https-proxy-socket")
  68}
  69
  70func (s Socket) mkdir() error {
  71        if err := s.checkPermissions(); err == nil {
  72                return nil
  73        } else if !os.IsNotExist(err) {
  74                return err
  75        }
  76        if err := os.MkdirAll(s.Dir, 0700); err != nil {
  77                return err
  78        }
  79        return s.checkPermissions()
  80}
  81
  82func (s Socket) checkPermissions() error {
  83        fi, err := os.Stat(s.Dir)
  84        if err != nil {
  85                return err
  86        }
  87        if !fi.IsDir() {
  88                return fmt.Errorf("socket: got file, want directory for %q", s.Dir)
  89        }
  90        if fi.Mode().Perm() != 0700 {
  91                return fmt.Errorf("socket: got perm %o, want 700 for %q", fi.Mode().Perm(), s.Dir)
  92        }
  93        if st := fi.Sys().(*syscall.Stat_t); int(st.Uid) != os.Getuid() {
  94                return fmt.Errorf("socket: got uid %d, want %d for %q", st.Uid, os.Getuid(), s.Dir)
  95        }
  96        return nil
  97}