diff options
Diffstat (limited to 'libpod/oci_conmon_exec_linux.go')
| -rw-r--r-- | libpod/oci_conmon_exec_linux.go | 599 |
1 files changed, 599 insertions, 0 deletions
diff --git a/libpod/oci_conmon_exec_linux.go b/libpod/oci_conmon_exec_linux.go new file mode 100644 index 000000000..51819f90a --- /dev/null +++ b/libpod/oci_conmon_exec_linux.go @@ -0,0 +1,599 @@ +package libpod + +import ( + "bufio" + "fmt" + "net" + "os" + "os/exec" + "path/filepath" + "syscall" + "time" + + "github.com/containers/common/pkg/config" + "github.com/containers/libpod/libpod/define" + "github.com/containers/libpod/pkg/errorhandling" + "github.com/containers/libpod/pkg/util" + "github.com/containers/libpod/utils" + "github.com/pkg/errors" + "github.com/sirupsen/logrus" + "golang.org/x/sys/unix" + "k8s.io/client-go/tools/remotecommand" +) + +// ExecContainer executes a command in a running container +func (r *ConmonOCIRuntime) ExecContainer(c *Container, sessionID string, options *ExecOptions, streams *define.AttachStreams) (int, chan error, error) { + if options == nil { + return -1, nil, errors.Wrapf(define.ErrInvalidArg, "must provide an ExecOptions struct to ExecContainer") + } + if len(options.Cmd) == 0 { + return -1, nil, errors.Wrapf(define.ErrInvalidArg, "must provide a command to execute") + } + + if sessionID == "" { + return -1, nil, errors.Wrapf(define.ErrEmptyID, "must provide a session ID for exec") + } + + // TODO: Should we default this to false? + // Or maybe make streams mandatory? + attachStdin := true + if streams != nil { + attachStdin = streams.AttachInput + } + + var ociLog string + if logrus.GetLevel() != logrus.DebugLevel && r.supportsJSON { + ociLog = c.execOCILog(sessionID) + } + + execCmd, pipes, err := r.startExec(c, sessionID, options, attachStdin, ociLog) + if err != nil { + return -1, nil, err + } + + // Only close sync pipe. Start and attach are consumed in the attach + // goroutine. + defer func() { + if pipes.syncPipe != nil && !pipes.syncClosed { + errorhandling.CloseQuiet(pipes.syncPipe) + pipes.syncClosed = true + } + }() + + // TODO Only create if !detach + // Attach to the container before starting it + attachChan := make(chan error) + go func() { + // attachToExec is responsible for closing pipes + attachChan <- c.attachToExec(streams, options.DetachKeys, sessionID, pipes.startPipe, pipes.attachPipe) + close(attachChan) + }() + + if err := execCmd.Wait(); err != nil { + return -1, nil, errors.Wrapf(err, "cannot run conmon") + } + + pid, err := readConmonPipeData(pipes.syncPipe, ociLog) + + return pid, attachChan, err +} + +// ExecContainerHTTP executes a new command in an existing container and +// forwards its standard streams over an attach +func (r *ConmonOCIRuntime) ExecContainerHTTP(ctr *Container, sessionID string, options *ExecOptions, httpConn net.Conn, httpBuf *bufio.ReadWriter, streams *HTTPAttachStreams, cancel <-chan bool) (int, chan error, error) { + if streams != nil { + if !streams.Stdin && !streams.Stdout && !streams.Stderr { + return -1, nil, errors.Wrapf(define.ErrInvalidArg, "must provide at least one stream to attach to") + } + } + + if options == nil { + return -1, nil, errors.Wrapf(define.ErrInvalidArg, "must provide exec options to ExecContainerHTTP") + } + + detachString := config.DefaultDetachKeys + if options.DetachKeys != nil { + detachString = *options.DetachKeys + } + detachKeys, err := processDetachKeys(detachString) + if err != nil { + return -1, nil, err + } + + // TODO: Should we default this to false? + // Or maybe make streams mandatory? + attachStdin := true + if streams != nil { + attachStdin = streams.Stdin + } + + var ociLog string + if logrus.GetLevel() != logrus.DebugLevel && r.supportsJSON { + ociLog = ctr.execOCILog(sessionID) + } + + execCmd, pipes, err := r.startExec(ctr, sessionID, options, attachStdin, ociLog) + if err != nil { + return -1, nil, err + } + + // Only close sync pipe. Start and attach are consumed in the attach + // goroutine. + defer func() { + if pipes.syncPipe != nil && !pipes.syncClosed { + errorhandling.CloseQuiet(pipes.syncPipe) + pipes.syncClosed = true + } + }() + + attachChan := make(chan error) + go func() { + // attachToExec is responsible for closing pipes + attachChan <- attachExecHTTP(ctr, sessionID, httpBuf, streams, pipes, detachKeys, options.Terminal, cancel) + close(attachChan) + }() + + // Wait for conmon to succeed, when return. + if err := execCmd.Wait(); err != nil { + return -1, nil, errors.Wrapf(err, "cannot run conmon") + } + + pid, err := readConmonPipeData(pipes.syncPipe, ociLog) + + return pid, attachChan, err +} + +// ExecContainerDetached executes a command in a running container, but does +// not attach to it. +func (r *ConmonOCIRuntime) ExecContainerDetached(ctr *Container, sessionID string, options *ExecOptions, stdin bool) (int, error) { + if options == nil { + return -1, errors.Wrapf(define.ErrInvalidArg, "must provide exec options to ExecContainerHTTP") + } + + var ociLog string + if logrus.GetLevel() != logrus.DebugLevel && r.supportsJSON { + ociLog = ctr.execOCILog(sessionID) + } + + execCmd, pipes, err := r.startExec(ctr, sessionID, options, stdin, ociLog) + if err != nil { + return -1, err + } + + defer func() { + pipes.cleanup() + }() + + // Wait for Conmon to tell us we're ready to attach. + // We aren't actually *going* to attach, but this means that we're good + // to proceed. + if _, err := readConmonPipeData(pipes.attachPipe, ""); err != nil { + return -1, err + } + + // Start the exec session + if err := writeConmonPipeData(pipes.startPipe); err != nil { + return -1, err + } + + // Wait for conmon to succeed, when return. + if err := execCmd.Wait(); err != nil { + return -1, errors.Wrapf(err, "cannot run conmon") + } + + pid, err := readConmonPipeData(pipes.syncPipe, ociLog) + + return pid, err +} + +// ExecAttachResize resizes the TTY of the given exec session. +func (r *ConmonOCIRuntime) ExecAttachResize(ctr *Container, sessionID string, newSize remotecommand.TerminalSize) error { + controlFile, err := openControlFile(ctr, ctr.execBundlePath(sessionID)) + if err != nil { + return err + } + defer controlFile.Close() + + if _, err = fmt.Fprintf(controlFile, "%d %d %d\n", 1, newSize.Height, newSize.Width); err != nil { + return errors.Wrapf(err, "failed to write to ctl file to resize terminal") + } + + return nil +} + +// ExecStopContainer stops a given exec session in a running container. +func (r *ConmonOCIRuntime) ExecStopContainer(ctr *Container, sessionID string, timeout uint) error { + pid, err := ctr.getExecSessionPID(sessionID) + if err != nil { + return err + } + + logrus.Debugf("Going to stop container %s exec session %s", ctr.ID(), sessionID) + + // Is the session dead? + // Ping the PID with signal 0 to see if it still exists. + if err := unix.Kill(pid, 0); err != nil { + if err == unix.ESRCH { + return nil + } + return errors.Wrapf(err, "error pinging container %s exec session %s PID %d with signal 0", ctr.ID(), sessionID, pid) + } + + if timeout > 0 { + // Use SIGTERM by default, then SIGSTOP after timeout. + logrus.Debugf("Killing exec session %s (PID %d) of container %s with SIGTERM", sessionID, pid, ctr.ID()) + if err := unix.Kill(pid, unix.SIGTERM); err != nil { + if err == unix.ESRCH { + return nil + } + return errors.Wrapf(err, "error killing container %s exec session %s PID %d with SIGTERM", ctr.ID(), sessionID, pid) + } + + // Wait for the PID to stop + if err := waitPidStop(pid, time.Duration(timeout)*time.Second); err != nil { + logrus.Warnf("Timed out waiting for container %s exec session %s to stop, resorting to SIGKILL", ctr.ID(), sessionID) + } else { + // No error, container is dead + return nil + } + } + + // SIGTERM did not work. On to SIGKILL. + logrus.Debugf("Killing exec session %s (PID %d) of container %s with SIGKILL", sessionID, pid, ctr.ID()) + if err := unix.Kill(pid, unix.SIGTERM); err != nil { + if err == unix.ESRCH { + return nil + } + return errors.Wrapf(err, "error killing container %s exec session %s PID %d with SIGKILL", ctr.ID(), sessionID, pid) + } + + // Wait for the PID to stop + if err := waitPidStop(pid, killContainerTimeout*time.Second); err != nil { + return errors.Wrapf(err, "timed out waiting for container %s exec session %s PID %d to stop after SIGKILL", ctr.ID(), sessionID, pid) + } + + return nil +} + +// ExecUpdateStatus checks if the given exec session is still running. +func (r *ConmonOCIRuntime) ExecUpdateStatus(ctr *Container, sessionID string) (bool, error) { + pid, err := ctr.getExecSessionPID(sessionID) + if err != nil { + return false, err + } + + logrus.Debugf("Checking status of container %s exec session %s", ctr.ID(), sessionID) + + // Is the session dead? + // Ping the PID with signal 0 to see if it still exists. + if err := unix.Kill(pid, 0); err != nil { + if err == unix.ESRCH { + return false, nil + } + return false, errors.Wrapf(err, "error pinging container %s exec session %s PID %d with signal 0", ctr.ID(), sessionID, pid) + } + + return true, nil +} + +// ExecContainerCleanup cleans up files created when a command is run via +// ExecContainer. This includes the attach socket for the exec session. +func (r *ConmonOCIRuntime) ExecContainerCleanup(ctr *Container, sessionID string) error { + // Clean up the sockets dir. Issue #3962 + // Also ignore if it doesn't exist for some reason; hence the conditional return below + if err := os.RemoveAll(filepath.Join(r.socketsDir, sessionID)); err != nil && !os.IsNotExist(err) { + return err + } + return nil +} + +// ExecAttachSocketPath is the path to a container's exec session attach socket. +func (r *ConmonOCIRuntime) ExecAttachSocketPath(ctr *Container, sessionID string) (string, error) { + // We don't even use container, so don't validity check it + if sessionID == "" { + return "", errors.Wrapf(define.ErrInvalidArg, "must provide a valid session ID to get attach socket path") + } + + return filepath.Join(r.socketsDir, sessionID, "attach"), nil +} + +// This contains pipes used by the exec API. +type execPipes struct { + syncPipe *os.File + syncClosed bool + startPipe *os.File + startClosed bool + attachPipe *os.File + attachClosed bool +} + +func (p *execPipes) cleanup() { + if p.syncPipe != nil && !p.syncClosed { + errorhandling.CloseQuiet(p.syncPipe) + p.syncClosed = true + } + if p.startPipe != nil && !p.startClosed { + errorhandling.CloseQuiet(p.startPipe) + p.startClosed = true + } + if p.attachPipe != nil && !p.attachClosed { + errorhandling.CloseQuiet(p.attachPipe) + p.attachClosed = true + } +} + +// Start an exec session's conmon parent from the given options. +func (r *ConmonOCIRuntime) startExec(c *Container, sessionID string, options *ExecOptions, attachStdin bool, ociLog string) (_ *exec.Cmd, _ *execPipes, deferredErr error) { + pipes := new(execPipes) + + if options == nil { + return nil, nil, errors.Wrapf(define.ErrInvalidArg, "must provide an ExecOptions struct to ExecContainer") + } + if len(options.Cmd) == 0 { + return nil, nil, errors.Wrapf(define.ErrInvalidArg, "must provide a command to execute") + } + + if sessionID == "" { + return nil, nil, errors.Wrapf(define.ErrEmptyID, "must provide a session ID for exec") + } + + // create sync pipe to receive the pid + parentSyncPipe, childSyncPipe, err := newPipe() + if err != nil { + return nil, nil, errors.Wrapf(err, "error creating socket pair") + } + pipes.syncPipe = parentSyncPipe + + defer func() { + if deferredErr != nil { + pipes.cleanup() + } + }() + + // create start pipe to set the cgroup before running + // attachToExec is responsible for closing parentStartPipe + childStartPipe, parentStartPipe, err := newPipe() + if err != nil { + return nil, nil, errors.Wrapf(err, "error creating socket pair") + } + pipes.startPipe = parentStartPipe + + // create the attach pipe to allow attach socket to be created before + // $RUNTIME exec starts running. This is to make sure we can capture all output + // from the process through that socket, rather than half reading the log, half attaching to the socket + // attachToExec is responsible for closing parentAttachPipe + parentAttachPipe, childAttachPipe, err := newPipe() + if err != nil { + return nil, nil, errors.Wrapf(err, "error creating socket pair") + } + pipes.attachPipe = parentAttachPipe + + childrenClosed := false + defer func() { + if !childrenClosed { + errorhandling.CloseQuiet(childSyncPipe) + errorhandling.CloseQuiet(childAttachPipe) + errorhandling.CloseQuiet(childStartPipe) + } + }() + + runtimeDir, err := util.GetRuntimeDir() + if err != nil { + return nil, nil, err + } + + finalEnv := make([]string, 0, len(options.Env)) + for k, v := range options.Env { + finalEnv = append(finalEnv, fmt.Sprintf("%s=%s", k, v)) + } + + processFile, err := prepareProcessExec(c, options.Cmd, finalEnv, options.Terminal, options.Cwd, options.User, sessionID) + if err != nil { + return nil, nil, err + } + + args := r.sharedConmonArgs(c, sessionID, c.execBundlePath(sessionID), c.execPidPath(sessionID), c.execLogPath(sessionID), c.execExitFileDir(sessionID), ociLog, "") + + if options.PreserveFDs > 0 { + args = append(args, formatRuntimeOpts("--preserve-fds", fmt.Sprintf("%d", options.PreserveFDs))...) + } + + for _, capability := range options.CapAdd { + args = append(args, formatRuntimeOpts("--cap", capability)...) + } + + if options.Terminal { + args = append(args, "-t") + } + + if attachStdin { + args = append(args, "-i") + } + + // Append container ID and command + args = append(args, "-e") + // TODO make this optional when we can detach + args = append(args, "--exec-attach") + args = append(args, "--exec-process-spec", processFile.Name()) + + if len(options.ExitCommand) > 0 { + args = append(args, "--exit-command", options.ExitCommand[0]) + for _, arg := range options.ExitCommand[1:] { + args = append(args, []string{"--exit-command-arg", arg}...) + } + } + + logrus.WithFields(logrus.Fields{ + "args": args, + }).Debugf("running conmon: %s", r.conmonPath) + // TODO: Need to pass this back so we can wait on it. + execCmd := exec.Command(r.conmonPath, args...) + + // TODO: This is commented because it doesn't make much sense in HTTP + // attach, and I'm not certain it does for non-HTTP attach as well. + // if streams != nil { + // // Don't add the InputStream to the execCmd. Instead, the data should be passed + // // through CopyDetachable + // if streams.AttachOutput { + // execCmd.Stdout = options.Streams.OutputStream + // } + // if streams.AttachError { + // execCmd.Stderr = options.Streams.ErrorStream + // } + // } + + conmonEnv, extraFiles, err := r.configureConmonEnv(runtimeDir) + if err != nil { + return nil, nil, err + } + + if options.PreserveFDs > 0 { + for fd := 3; fd < int(3+options.PreserveFDs); fd++ { + execCmd.ExtraFiles = append(execCmd.ExtraFiles, os.NewFile(uintptr(fd), fmt.Sprintf("fd-%d", fd))) + } + } + + // we don't want to step on users fds they asked to preserve + // Since 0-2 are used for stdio, start the fds we pass in at preserveFDs+3 + execCmd.Env = r.conmonEnv + execCmd.Env = append(execCmd.Env, fmt.Sprintf("_OCI_SYNCPIPE=%d", options.PreserveFDs+3), fmt.Sprintf("_OCI_STARTPIPE=%d", options.PreserveFDs+4), fmt.Sprintf("_OCI_ATTACHPIPE=%d", options.PreserveFDs+5)) + execCmd.Env = append(execCmd.Env, conmonEnv...) + + execCmd.ExtraFiles = append(execCmd.ExtraFiles, childSyncPipe, childStartPipe, childAttachPipe) + execCmd.ExtraFiles = append(execCmd.ExtraFiles, extraFiles...) + execCmd.Dir = c.execBundlePath(sessionID) + execCmd.SysProcAttr = &syscall.SysProcAttr{ + Setpgid: true, + } + + err = startCommandGivenSelinux(execCmd) + + // We don't need children pipes on the parent side + errorhandling.CloseQuiet(childSyncPipe) + errorhandling.CloseQuiet(childAttachPipe) + errorhandling.CloseQuiet(childStartPipe) + childrenClosed = true + + if err != nil { + return nil, nil, errors.Wrapf(err, "cannot start container %s", c.ID()) + } + if err := r.moveConmonToCgroupAndSignal(c, execCmd, parentStartPipe); err != nil { + return nil, nil, err + } + + if options.PreserveFDs > 0 { + for fd := 3; fd < int(3+options.PreserveFDs); fd++ { + // These fds were passed down to the runtime. Close them + // and not interfere + if err := os.NewFile(uintptr(fd), fmt.Sprintf("fd-%d", fd)).Close(); err != nil { + logrus.Debugf("unable to close file fd-%d", fd) + } + } + } + + return execCmd, pipes, nil +} + +// Attach to a container over HTTP +func attachExecHTTP(c *Container, sessionID string, httpBuf *bufio.ReadWriter, streams *HTTPAttachStreams, pipes *execPipes, detachKeys []byte, isTerminal bool, cancel <-chan bool) error { + if pipes == nil || pipes.startPipe == nil || pipes.attachPipe == nil { + return errors.Wrapf(define.ErrInvalidArg, "must provide a start and attach pipe to finish an exec attach") + } + + defer func() { + if !pipes.startClosed { + errorhandling.CloseQuiet(pipes.startPipe) + pipes.startClosed = true + } + if !pipes.attachClosed { + errorhandling.CloseQuiet(pipes.attachPipe) + pipes.attachClosed = true + } + }() + + logrus.Debugf("Attaching to container %s exec session %s", c.ID(), sessionID) + + // set up the socket path, such that it is the correct length and location for exec + sockPath, err := c.execAttachSocketPath(sessionID) + if err != nil { + return err + } + socketPath := buildSocketPath(sockPath) + + // 2: read from attachFd that the parent process has set up the console socket + if _, err := readConmonPipeData(pipes.attachPipe, ""); err != nil { + return err + } + + // 2: then attach + conn, err := net.DialUnix("unixpacket", nil, &net.UnixAddr{Name: socketPath, Net: "unixpacket"}) + if err != nil { + return errors.Wrapf(err, "failed to connect to container's attach socket: %v", socketPath) + } + defer func() { + if err := conn.Close(); err != nil { + logrus.Errorf("unable to close socket: %q", err) + } + }() + + // Make a channel to pass errors back + errChan := make(chan error) + + attachStdout := true + attachStderr := true + attachStdin := true + if streams != nil { + attachStdout = streams.Stdout + attachStderr = streams.Stderr + attachStdin = streams.Stdin + } + + // Next, STDIN. Avoid entirely if attachStdin unset. + if attachStdin { + go func() { + logrus.Debugf("Beginning STDIN copy") + _, err := utils.CopyDetachable(conn, httpBuf, detachKeys) + logrus.Debugf("STDIN copy completed") + errChan <- err + }() + } + + // 4: send start message to child + if err := writeConmonPipeData(pipes.startPipe); err != nil { + return err + } + + // Handle STDOUT/STDERR *after* start message is sent + go func() { + var err error + if isTerminal { + // Hack: return immediately if attachStdout not set to + // emulate Docker. + // Basically, when terminal is set, STDERR goes nowhere. + // Everything does over STDOUT. + // Therefore, if not attaching STDOUT - we'll never copy + // anything from here. + logrus.Debugf("Performing terminal HTTP attach for container %s", c.ID()) + if attachStdout { + err = httpAttachTerminalCopy(conn, httpBuf, c.ID()) + } + } else { + logrus.Debugf("Performing non-terminal HTTP attach for container %s", c.ID()) + err = httpAttachNonTerminalCopy(conn, httpBuf, c.ID(), attachStdin, attachStdout, attachStderr) + } + errChan <- err + logrus.Debugf("STDOUT/ERR copy completed") + }() + + if cancel != nil { + select { + case err := <-errChan: + return err + case <-cancel: + return nil + } + } else { + var connErr error = <-errChan + return connErr + } +} |