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Merge pull request #141 from vishh/runin_support 

Change nsenter to support docker 'runin'
This commit is contained in:
Michael Crosby 2014-08-05 15:18:39 -07:00
parent 54cf66e07b f90eee10ef
commit f79bccbcf0
6 changed files with 80 additions and 160 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...)

96
namespaces/nsenter.go
View File

@ -16,6 +16,7 @@ package namespaces
#include <getopt.h>
static const kBufSize = 256;
static const char *kNsEnter = "nsenter";
void get_args(int *argc, char ***argv) {
// Read argv
@ -58,7 +59,7 @@ 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
@ -68,34 +69,37 @@ void print_usage() {
}
void nsenter() {
int argc;
int argc, c;
char **argv;
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);
int found_nsenter = 0;
for (c = 0; c < argc; ++c) {
if (strcmp(argv[c], kNsEnter) == 0) {
found_nsenter = 1;
break;
}
}
if (!found_nsenter) {
return;
}
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 +113,18 @@ void nsenter() {
}
}
if (strcmp(argv[optind - 2], kNsEnter) != 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 +132,20 @@ 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 +180,20 @@ 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;

5
nsinit/cli.go
View File

@ -24,7 +24,10 @@ func NsInit() {
app.Name = "nsinit"
app.Version = "0.1"
app.Author = "libcontainer maintainers"
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 {