next-eeze-agent.git

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193

package main

import (
	"log"
	"net"
	"os"
	"os/signal"
	"os/user"
	"strconv"
	"strings"
	"syscall"
	"time"

	"git.sr.ht/~sircmpwn/go-bare"
	"github.com/sevlyar/go-daemon"
)

// todo memguard
var PASSWORD = ""

func getUser() (*user.User, error) {
	u, err := user.Current()
	if err != nil {
		log.Println("error getting user", err)
		return nil, err
	}
	return u, nil
}

func getUserByName(username string) (*user.User, error) {
	u, err := user.Lookup(username)
	if err != nil {
		log.Println("error getting user", err)
		return nil, err
	}
	return u, nil
}

func socketName(u string) string {
	return "/tmp/eeze-agent-" + u
}

func timeOut(timeout int, sigc chan os.Signal) {
	time.Sleep(time.Duration(timeout) * time.Second)
	sigc <- syscall.SIGINT
}

func catch(sigc chan os.Signal, socket string) {
	_ = <-sigc
	os.Remove(socket)
	log.Println("bye")
	os.Exit(0)
}

func handle(conn net.Conn) error {
	r := bare.NewReader(conn)
	cmd, err := r.ReadU8()
	if err != nil {
		log.Println("error reading command", err)
		return err
	}
	switch cmd {
	case 0:
		// todo memguard
		password, err := r.ReadString()
		if err != nil {
			log.Println("error reading password to store", err)
			return err
		}
		PASSWORD = password
	case 1:
		w := bare.NewWriter(conn)
		err = w.WriteString(PASSWORD)
		if err != nil {
			log.Println("error giving password", err)
			return err
		}
	default:
		return nil
	}
	return nil
}

func parseTimeout(timeout string) int {
	i, err := strconv.ParseInt(timeout, 10, 64)
	if err != nil {
		log.Println("error parsing timeout, defualting to 300s", err)
	} else if i < 0 {
		log.Println("timeout cannot be < 0, defualting to 300s", err)
	} else {
		return int(i)
	}
	return 300
}

func main() {
	log.Println("main")
	timeout := 300
	skipArg := true
	user, err := getUser()
	if err != nil {
		log.Println("error getting user name", err)
		return
	}
	for i, arg := range os.Args {
		if skipArg {
			skipArg = false
			continue
		}
		if arg == "-u" {
			u, err := getUserByName(os.Args[i+1])
			if err != nil {
				log.Println("error getting user from name", err)
			} else {
				user = u
			}
			skipArg = true
		} else {
			timeout = parseTimeout(arg)
		}
	}
	log.Println("read args ", timeout)
	socket := socketName(user.Username)
	log.Println("socket name ", socket)

	uid, err := strconv.ParseInt(user.Uid, 10, 64)
	if err != nil {
		log.Println("error parsing uid", err)
		return
	}
	gid, err := strconv.ParseInt(user.Gid, 10, 64)
	if err != nil {
		log.Println("error parsing gid", err)
		return
	}
	context := new(daemon.Context)
	context.LogFileName = socket + ".ctx.log"
	log.Println("ctx ", context)
	child, err := context.Reborn()
	if err != nil {
		log.Println("error forking", err)
		return
	}
	log.Println("reborn")

	if child != nil {
		log.Println("waiting for socket")
		i := 10000
		for true {
			_, err := os.Stat(socket)
			if err == nil || !strings.Contains(err.Error(), "no such file or directory") {
				os.Chown(socket, int(uid), int(gid))
				os.Chmod(socket, 0600)
				os.Chmod(context.LogFileName, 0644)
				log.Println("chmoded socket")
				break
			}
			i--
		}
		log.Println("socket exists")
		return
	} else {
		defer context.Release()
		sigc := make(chan os.Signal, 1)
		log.Println("made channel")
		signal.Notify(sigc, syscall.SIGHUP, syscall.SIGINT, syscall.SIGTERM, syscall.SIGQUIT)
		log.Println("setup signal")
		go catch(sigc, socket)
		log.Println("ran catch")
		if timeout > 0 {
			go timeOut(timeout, sigc)
			log.Println("ran timeout")
		}

		server, err := net.Listen("unix", socket)
		if err != nil {
			log.Println("error listening", err)
			return
		}
		log.Println("listening")

		log.Println("accepting")
		for {
			conn, err := server.Accept()
			if err != nil {
				log.Println("error accepting", err)
				return
			}
			go handle(conn)
		}
	}

}