зеркало из https://github.com/microsoft/docker.git
92 строки
1.9 KiB
Go
92 строки
1.9 KiB
Go
package docker
|
|
|
|
import (
|
|
"flag"
|
|
"fmt"
|
|
"log"
|
|
"os"
|
|
"os/exec"
|
|
"os/user"
|
|
"strconv"
|
|
"syscall"
|
|
)
|
|
|
|
// Setup networking
|
|
func setupNetworking(gw string) {
|
|
if gw == "" {
|
|
return
|
|
}
|
|
cmd := exec.Command("/sbin/route", "add", "default", "gw", gw)
|
|
if err := cmd.Run(); err != nil {
|
|
log.Fatalf("Unable to set up networking: %v", err)
|
|
}
|
|
}
|
|
|
|
// Takes care of dropping privileges to the desired user
|
|
func changeUser(u string) {
|
|
if u == "" {
|
|
return
|
|
}
|
|
userent, err := user.LookupId(u)
|
|
if err != nil {
|
|
userent, err = user.Lookup(u)
|
|
}
|
|
if err != nil {
|
|
log.Fatalf("Unable to find user %v: %v", u, err)
|
|
}
|
|
|
|
uid, err := strconv.Atoi(userent.Uid)
|
|
if err != nil {
|
|
log.Fatalf("Invalid uid: %v", userent.Uid)
|
|
}
|
|
gid, err := strconv.Atoi(userent.Gid)
|
|
if err != nil {
|
|
log.Fatalf("Invalid gid: %v", userent.Gid)
|
|
}
|
|
|
|
if err := syscall.Setgid(gid); err != nil {
|
|
log.Fatalf("setgid failed: %v", err)
|
|
}
|
|
if err := syscall.Setuid(uid); err != nil {
|
|
log.Fatalf("setuid failed: %v", err)
|
|
}
|
|
}
|
|
|
|
// Set the environment to a known, repeatable state
|
|
func setupEnv() {
|
|
os.Clearenv()
|
|
os.Setenv("HOME", "/")
|
|
os.Setenv("PATH", "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin")
|
|
}
|
|
|
|
func executeProgram(name string, args []string) {
|
|
path, err := exec.LookPath(name)
|
|
if err != nil {
|
|
log.Printf("Unable to locate %v", name)
|
|
os.Exit(127)
|
|
}
|
|
|
|
if err := syscall.Exec(path, args, os.Environ()); err != nil {
|
|
panic(err)
|
|
}
|
|
}
|
|
|
|
// Sys Init code
|
|
// This code is run INSIDE the container and is responsible for setting
|
|
// up the environment before running the actual process
|
|
func SysInit() {
|
|
if len(os.Args) <= 1 {
|
|
fmt.Println("You should not invoke docker-init manually")
|
|
os.Exit(1)
|
|
}
|
|
var u = flag.String("u", "", "username or uid")
|
|
var gw = flag.String("g", "", "gateway address")
|
|
|
|
flag.Parse()
|
|
|
|
setupNetworking(*gw)
|
|
changeUser(*u)
|
|
setupEnv()
|
|
executeProgram(flag.Arg(0), flag.Args())
|
|
}
|