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Docker 'runin' demands passing flags before 'nsenter' cli option. 

Docker does not require RunIn API. Hence that API has been removed.
nsinit CLI has been modified to work around the nsenter changes.

Docker-DCO-1.1-Signed-off-by: Vishnu Kannan <vishnuk@google.com> (github: vishh)
This commit is contained in:
Vishnu Kannan 2014-08-04 22:05:50 +00:00
parent 54cf66e07b
commit e5e40b6ef0
6 changed files with 70 additions and 158 deletions
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24
cgroups/cgutil/cgutil.go
View File

@ -18,8 +18,8 @@ var createCommand = cli.Command{
Name: "create",
Usage: "Create a cgroup container using the supplied configuration and initial process.",
Flags: []cli.Flag{
cli.StringFlag{"config, c", "cgroup.json", "path to container configuration (cgroups.Cgroup object)"},
cli.IntFlag{"pid, p", 0, "pid of the initial process in the container"},
cli.StringFlag{Name: "config, c", Value: "cgroup.json", Usage: "path to container configuration (cgroups.Cgroup object)"},
cli.IntFlag{Name: "pid, p", Value: 0, Usage: "pid of the initial process in the container"},
},
Action: createAction,
}
@ -28,8 +28,8 @@ var destroyCommand = cli.Command{
Name: "destroy",
Usage: "Destroy an existing cgroup container.",
Flags: []cli.Flag{
cli.StringFlag{"name, n", "", "container name"},
cli.StringFlag{"parent, p", "", "container parent"},
cli.StringFlag{Name: "name, n", Value: "", Usage: "container name"},
cli.StringFlag{Name: "parent, p", Value: "", Usage: "container parent"},
},
Action: destroyAction,
}
@ -38,8 +38,8 @@ var statsCommand = cli.Command{
Name: "stats",
Usage: "Get stats for cgroup",
Flags: []cli.Flag{
cli.StringFlag{"name, n", "", "container name"},
cli.StringFlag{"parent, p", "", "container parent"},
cli.StringFlag{Name: "name, n", Value: "", Usage: "container name"},
cli.StringFlag{Name: "parent, p", Value: "", Usage: "container parent"},
},
Action: statsAction,
}
@ -48,8 +48,8 @@ var pauseCommand = cli.Command{
Name: "pause",
Usage: "Pause cgroup",
Flags: []cli.Flag{
cli.StringFlag{"name, n", "", "container name"},
cli.StringFlag{"parent, p", "", "container parent"},
cli.StringFlag{Name: "name, n", Value: "", Usage: "container name"},
cli.StringFlag{Name: "parent, p", Value: "", Usage: "container parent"},
},
Action: pauseAction,
}
@ -58,8 +58,8 @@ var resumeCommand = cli.Command{
Name: "resume",
Usage: "Resume a paused cgroup",
Flags: []cli.Flag{
cli.StringFlag{"name, n", "", "container name"},
cli.StringFlag{"parent, p", "", "container parent"},
cli.StringFlag{Name: "name, n", Value: "", Usage: "container name"},
cli.StringFlag{Name: "parent, p", Value: "", Usage: "container parent"},
},
Action: resumeAction,
}
@ -68,8 +68,8 @@ var psCommand = cli.Command{
Name: "ps",
Usage: "Get list of pids for a cgroup",
Flags: []cli.Flag{
cli.StringFlag{"name, n", "", "container name"},
cli.StringFlag{"parent, p", "", "container parent"},
cli.StringFlag{Name: "name, n", Value: "", Usage: "container name"},
cli.StringFlag{Name: "parent, p", Value: "", Usage: "container parent"},
},
Action: psAction,
}

46
namespaces/execin.go
View File

@ -4,52 +4,18 @@ package namespaces
import (
"encoding/json"
"os"
"strconv"
"github.com/docker/libcontainer"
"github.com/docker/libcontainer/label"
"github.com/docker/libcontainer/system"
"io"
"os"
"os/exec"
"strconv"
"syscall"
)
// Runs the command under 'args' inside an existing container referred to by 'container'.
// Returns the exitcode of the command upon success and appropriate error on failure.
func RunIn(container *libcontainer.Config, state *libcontainer.State, args []string, nsinitPath string, stdin io.Reader, stdout, stderr io.Writer, console string, startCallback func(*exec.Cmd)) (int, error) {
initArgs, err := getNsEnterCommand(strconv.Itoa(state.InitPid), container, console, args)
if err != nil {
return -1, err
}
cmd := exec.Command(nsinitPath, initArgs...)
// Note: these are only used in non-tty mode
// if there is a tty for the container it will be opened within the namespace and the
// fds will be duped to stdin, stdiout, and stderr
cmd.Stdin = stdin
cmd.Stdout = stdout
cmd.Stderr = stderr
if err := cmd.Start(); err != nil {
return -1, err
}
if startCallback != nil {
startCallback(cmd)
}
if err := cmd.Wait(); err != nil {
if _, ok := err.(*exec.ExitError); !ok {
return -1, err
}
}
return cmd.ProcessState.Sys().(syscall.WaitStatus).ExitStatus(), nil
}
// ExecIn uses an existing pid and joins the pid's namespaces with the new command.
func ExecIn(container *libcontainer.Config, state *libcontainer.State, args []string) error {
// Enter the namespace and then finish setup
args, err := getNsEnterCommand(strconv.Itoa(state.InitPid), container, "", args)
args, err := GetNsEnterCommand(strconv.Itoa(state.InitPid), container, "", args)
if err != nil {
return err
}
@ -73,14 +39,13 @@ func getContainerJson(container *libcontainer.Config) (string, error) {
return string(containerJson), nil
}
func getNsEnterCommand(initPid string, container *libcontainer.Config, console string, args []string) ([]string, error) {
func GetNsEnterCommand(initPid string, container *libcontainer.Config, console string, args []string) ([]string, error) {
containerJson, err := getContainerJson(container)
if err != nil {
return nil, err
}
out := []string{
"nsenter",
"--nspid", initPid,
"--containerjson", containerJson,
}
@ -88,6 +53,7 @@ func getNsEnterCommand(initPid string, container *libcontainer.Config, console s
if console != "" {
out = append(out, "--console", console)
}
out = append(out, "nsenter")
out = append(out, "--")
out = append(out, args...)

83
namespaces/nsenter.go
View File

@ -58,7 +58,7 @@ void get_args(int *argc, char ***argv) {
#include "syscall.h"
#ifdef SYS_setns
int setns(int fd, int nstype) {
return syscall(SYS_setns, fd, nstype);
return syscall(SYS_setns, fd, nstype);
}
#endif
#endif
@ -73,29 +73,24 @@ void nsenter() {
get_args(&argc, &argv);
// Ignore if this is not for us.
if (argc < 2 || strcmp(argv[1], "nsenter") != 0) {
if (argc < 6) {
return;
}
// USAGE: <binary> nsenter <PID> <process label> <container JSON> <argv>...
if (argc < 6) {
fprintf(stderr, "nsenter: Incorrect usage, not enough arguments\n");
exit(1);
}
static const struct option longopts[] = {
{ "nspid", required_argument, NULL, 'n' },
{ "nspid", required_argument, NULL, 'n' },
{ "containerjson", required_argument, NULL, 'c' },
{ "console", required_argument, NULL, 't' },
{ NULL, 0, NULL, 0 }
{ "console", optional_argument, NULL, 't' },
{ NULL, 0, NULL, 0 }
};
int c;
pid_t init_pid = -1;
char *init_pid_str = NULL;
char *container_json = NULL;
char *console = NULL;
while ((c = getopt_long_only(argc, argv, "n:s:c:", longopts, NULL)) != -1) {
char *console = NULL;
opterr = 0;
while ((c = getopt_long_only(argc, argv, "-n:s:c:", longopts, NULL)) != -1) {
switch (c) {
case 'n':
init_pid_str = optarg;
@ -109,14 +104,18 @@ void nsenter() {
}
}
if (strcmp(argv[optind - 2], "nsenter") != 0) {
return;
}
if (container_json == NULL || init_pid_str == NULL) {
print_usage();
exit(1);
}
init_pid = strtol(init_pid_str, NULL, 10);
if (errno != 0 || init_pid <= 0) {
fprintf(stderr, "nsenter: Failed to parse PID from \"%s\" with error: \"%s\"\n", init_pid_str, strerror(errno));
if ((init_pid == 0 && errno == EINVAL) || errno == ERANGE) {
fprintf(stderr, "nsenter: Failed to parse PID from \"%s\" with output \"%d\" and error: \"%s\"\n", init_pid_str, init_pid, strerror(errno));
print_usage();
exit(1);
}
@ -124,20 +123,20 @@ void nsenter() {
argc -= 3;
argv += 3;
if (setsid() == -1) {
fprintf(stderr, "setsid failed. Error: %s\n", strerror(errno));
exit(1);
}
if (setsid() == -1) {
fprintf(stderr, "setsid failed. Error: %s\n", strerror(errno));
exit(1);
}
// before we setns we need to dup the console
int consolefd = -1;
if (console != NULL) {
consolefd = open(console, O_RDWR);
if (consolefd < 0) {
fprintf(stderr, "nsenter: failed to open console %s %s\n", console, strerror(errno));
exit(1);
}
}
// before we setns we need to dup the console
int consolefd = -1;
if (console != NULL) {
consolefd = open(console, O_RDWR);
if (consolefd < 0) {
fprintf(stderr, "nsenter: failed to open console %s %s\n", console, strerror(errno));
exit(1);
}
}
// Setns on all supported namespaces.
char ns_dir[PATH_MAX];
@ -172,20 +171,20 @@ void nsenter() {
// We must fork to actually enter the PID namespace.
int child = fork();
if (child == 0) {
if (consolefd != -1) {
if (dup2(consolefd, STDIN_FILENO) != 0) {
fprintf(stderr, "nsenter: failed to dup 0 %s\n", strerror(errno));
exit(1);
}
if (dup2(consolefd, STDOUT_FILENO) != STDOUT_FILENO) {
fprintf(stderr, "nsenter: failed to dup 1 %s\n", strerror(errno));
exit(1);
}
if (dup2(consolefd, STDERR_FILENO) != STDERR_FILENO) {
fprintf(stderr, "nsenter: failed to dup 2 %s\n", strerror(errno));
exit(1);
}
}
if (consolefd != -1) {
if (dup2(consolefd, STDIN_FILENO) != 0) {
fprintf(stderr, "nsenter: failed to dup 0 %s\n", strerror(errno));
exit(1);
}
if (dup2(consolefd, STDOUT_FILENO) != STDOUT_FILENO) {
fprintf(stderr, "nsenter: failed to dup 1 %s\n", strerror(errno));
exit(1);
}
if (dup2(consolefd, STDERR_FILENO) != STDERR_FILENO) {
fprintf(stderr, "nsenter: failed to dup 2 %s\n", strerror(errno));
exit(1);
}
}
// Finish executing, let the Go runtime take over.
return;

6
nsinit/cli.go
View File

@ -24,7 +24,11 @@ func NsInit() {
app.Name = "nsinit"
app.Version = "0.1"
app.Author = "libcontainer maintainers"
// These are local to 'nsenter' but are exposed globally because of namespaces.NsEnter is used by DockerInit which does not understand sub-commands.
app.Flags = []cli.Flag{
cli.StringFlag{Name: "nspid"},
cli.StringFlag{Name: "containerjson"},
cli.StringFlag{Name: "console"}}
app.Before = preload
app.Commands = []cli.Command{
execCommand,

55
nsinit/exec.go
View File

@ -36,7 +36,7 @@ func execAction(context *cli.Context) {
}
if state != nil {
exitCode, err = runIn(container, state, []string(context.Args()))
err = namespaces.ExecIn(container, state, []string(context.Args()))
} else {
exitCode, err = startContainer(container, dataPath, []string(context.Args()))
}
@ -48,59 +48,6 @@ func execAction(context *cli.Context) {
os.Exit(exitCode)
}
func runIn(container *libcontainer.Config, state *libcontainer.State, args []string) (int, error) {
var (
master *os.File
console string
err error
stdin = os.Stdin
stdout = os.Stdout
stderr = os.Stderr
sigc = make(chan os.Signal, 10)
)
signal.Notify(sigc)
if container.Tty {
stdin = nil
stdout = nil
stderr = nil
master, console, err = consolepkg.CreateMasterAndConsole()
if err != nil {
log.Fatal(err)
}
go io.Copy(master, os.Stdin)
go io.Copy(os.Stdout, master)
state, err := term.SetRawTerminal(os.Stdin.Fd())
if err != nil {
log.Fatal(err)
}
defer term.RestoreTerminal(os.Stdin.Fd(), state)
}
startCallback := func(cmd *exec.Cmd) {
go func() {
resizeTty(master)
for sig := range sigc {
switch sig {
case syscall.SIGWINCH:
resizeTty(master)
default:
cmd.Process.Signal(sig)
}
}
}()
}
return namespaces.RunIn(container, state, args, os.Args[0], stdin, stdout, stderr, console, startCallback)
}
// startContainer starts the container. Returns the exit status or -1 and an
// error.
//

14
nsinit/nsenter.go
View File

@ -2,6 +2,7 @@ package nsinit
import (
"log"
"strconv"
"github.com/codegangsta/cli"
"github.com/docker/libcontainer/namespaces"
@ -11,11 +12,6 @@ var nsenterCommand = cli.Command{
Name: "nsenter",
Usage: "init process for entering an existing namespace",
Action: nsenterAction,
Flags: []cli.Flag{
cli.IntFlag{Name: "nspid"},
cli.StringFlag{Name: "containerjson"},
cli.StringFlag{Name: "console"},
},
}
func nsenterAction(context *cli.Context) {
@ -25,14 +21,14 @@ func nsenterAction(context *cli.Context) {
args = []string{"/bin/bash"}
}
container, err := loadContainerFromJson(context.String("containerjson"))
container, err := loadContainerFromJson(context.GlobalString("containerjson"))
if err != nil {
log.Fatalf("unable to load container: %s", err)
}
nspid := context.Int("nspid")
if nspid <= 0 {
log.Fatalf("cannot enter into namespaces without valid pid: %q", nspid)
nspid, err := strconv.Atoi(context.GlobalString("nspid"))
if nspid <= 0 || err != nil {
log.Fatalf("cannot enter into namespaces without valid pid: %q - %s", nspid, err)
}
if err := namespaces.NsEnter(container, args); err != nil {