зеркало из https://github.com/microsoft/docker.git
100 строки
2.0 KiB
Go
100 строки
2.0 KiB
Go
package docker
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import (
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"flag"
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"fmt"
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"log"
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"os"
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"os/exec"
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"os/user"
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"strconv"
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"strings"
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"syscall"
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)
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// Setup networking
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func setupNetworking(gw string) {
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if gw == "" {
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return
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}
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if _, err := ip("route", "add", "default", "via", gw); err != nil {
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log.Fatalf("Unable to set up networking: %v", err)
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}
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}
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// Takes care of dropping privileges to the desired user
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func changeUser(u string) {
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if u == "" {
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return
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}
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userent, err := user.LookupId(u)
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if err != nil {
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userent, err = user.Lookup(u)
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}
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if err != nil {
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log.Fatalf("Unable to find user %v: %v", u, err)
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}
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uid, err := strconv.Atoi(userent.Uid)
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if err != nil {
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log.Fatalf("Invalid uid: %v", userent.Uid)
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}
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gid, err := strconv.Atoi(userent.Gid)
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if err != nil {
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log.Fatalf("Invalid gid: %v", userent.Gid)
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}
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if err := syscall.Setgid(gid); err != nil {
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log.Fatalf("setgid failed: %v", err)
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}
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if err := syscall.Setuid(uid); err != nil {
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log.Fatalf("setuid failed: %v", err)
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}
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}
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// Clear environment pollution introduced by lxc-start
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func cleanupEnv(env ListOpts) {
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os.Clearenv()
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for _, kv := range env {
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parts := strings.SplitN(kv, "=", 2)
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if len(parts) == 1 {
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parts = append(parts, "")
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}
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os.Setenv(parts[0], parts[1])
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}
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}
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func executeProgram(name string, args []string) {
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path, err := exec.LookPath(name)
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if err != nil {
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log.Printf("Unable to locate %v", name)
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os.Exit(127)
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}
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if err := syscall.Exec(path, args, os.Environ()); err != nil {
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panic(err)
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}
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}
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// Sys Init code
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// This code is run INSIDE the container and is responsible for setting
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// up the environment before running the actual process
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func SysInit() {
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if len(os.Args) <= 1 {
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fmt.Println("You should not invoke docker-init manually")
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os.Exit(1)
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}
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var u = flag.String("u", "", "username or uid")
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var gw = flag.String("g", "", "gateway address")
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var flEnv ListOpts
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flag.Var(&flEnv, "e", "Set environment variables")
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flag.Parse()
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cleanupEnv(flEnv)
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setupNetworking(*gw)
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changeUser(*u)
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executeProgram(flag.Arg(0), flag.Args())
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}
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