Godeps: Bump go-systemd, add coreos/pkg/dlopen.

vendor/github.com/coreos/go-systemd/dbus/dbus.go

@@ -86,7 +86,7 @@ type Conn struct {
 // New establishes a connection to the system bus and authenticates.
 // Callers should call Close() when done with the connection.
 func New() (*Conn, error) {
-	return newConnection(func() (*dbus.Conn, error) {
+	return NewConnection(func() (*dbus.Conn, error) {
 		return dbusAuthHelloConnection(dbus.SystemBusPrivate)
 	})
 }
@@ -95,7 +95,7 @@ func New() (*Conn, error) {
 // authenticates. This can be used to connect to systemd user instances.
 // Callers should call Close() when done with the connection.
 func NewUserConnection() (*Conn, error) {
-	return newConnection(func() (*dbus.Conn, error) {
+	return NewConnection(func() (*dbus.Conn, error) {
 		return dbusAuthHelloConnection(dbus.SessionBusPrivate)
 	})
 }
@@ -104,7 +104,7 @@ func NewUserConnection() (*Conn, error) {
 // This can be used for communicating with systemd without a dbus daemon.
 // Callers should call Close() when done with the connection.
 func NewSystemdConnection() (*Conn, error) {
-	return newConnection(func() (*dbus.Conn, error) {
+	return NewConnection(func() (*dbus.Conn, error) {
 		// We skip Hello when talking directly to systemd.
 		return dbusAuthConnection(func() (*dbus.Conn, error) {
 			return dbus.Dial("unix:path=/run/systemd/private")
@@ -118,13 +118,18 @@ func (c *Conn) Close() {
 	c.sigconn.Close()
 }
 
-func newConnection(createBus func() (*dbus.Conn, error)) (*Conn, error) {
-	sysconn, err := createBus()
+// NewConnection establishes a connection to a bus using a caller-supplied function.
+// This allows connecting to remote buses through a user-supplied mechanism.
+// The supplied function may be called multiple times, and should return independent connections.
+// The returned connection must be fully initialised: the org.freedesktop.DBus.Hello call must have succeeded,
+// and any authentication should be handled by the function.
+func NewConnection(dialBus func() (*dbus.Conn, error)) (*Conn, error) {
+	sysconn, err := dialBus()
 	if err != nil {
 		return nil, err
 	}
 
-	sigconn, err := createBus()
+	sigconn, err := dialBus()
 	if err != nil {
 		sysconn.Close()
 		return nil, err
@@ -148,6 +153,17 @@ func newConnection(createBus func() (*dbus.Conn, error)) (*Conn, error) {
 	return c, nil
 }
 
+// GetManagerProperty returns the value of a property on the org.freedesktop.systemd1.Manager
+// interface. The value is returned in its string representation, as defined at
+// https://developer.gnome.org/glib/unstable/gvariant-text.html
+func (c *Conn) GetManagerProperty(prop string) (string, error) {
+	variant, err := c.sysobj.GetProperty("org.freedesktop.systemd1.Manager." + prop)
+	if err != nil {
+		return "", err
+	}
+	return variant.String(), nil
+}
+
 func dbusAuthConnection(createBus func() (*dbus.Conn, error)) (*dbus.Conn, error) {
 	conn, err := createBus()
 	if err != nil {

vendor/github.com/coreos/go-systemd/dbus/methods.go

@@ -199,6 +199,11 @@ func (c *Conn) GetUnitProperty(unit string, propertyName string) (*Property, err
 	return c.getProperty(unit, "org.freedesktop.systemd1.Unit", propertyName)
 }
 
+// GetServiceProperty returns property for given service name and property name
+func (c *Conn) GetServiceProperty(service string, propertyName string) (*Property, error) {
+	return c.getProperty(service, "org.freedesktop.systemd1.Service", propertyName)
+}
+
 // GetUnitTypeProperties returns the extra properties for a unit, specific to the unit type.
 // Valid values for unitType: Service, Socket, Target, Device, Mount, Automount, Snapshot, Timer, Swap, Path, Slice, Scope
 // return "dbus.Error: Unknown interface" if the unitType is not the correct type of the unit
@@ -221,6 +226,19 @@ func (c *Conn) GetUnitTypeProperty(unit string, unitType string, propertyName st
 	return c.getProperty(unit, "org.freedesktop.systemd1."+unitType, propertyName)
 }
 
+type UnitStatus struct {
+	Name        string          // The primary unit name as string
+	Description string          // The human readable description string
+	LoadState   string          // The load state (i.e. whether the unit file has been loaded successfully)
+	ActiveState string          // The active state (i.e. whether the unit is currently started or not)
+	SubState    string          // The sub state (a more fine-grained version of the active state that is specific to the unit type, which the active state is not)
+	Followed    string          // A unit that is being followed in its state by this unit, if there is any, otherwise the empty string.
+	Path        dbus.ObjectPath // The unit object path
+	JobId       uint32          // If there is a job queued for the job unit the numeric job id, 0 otherwise
+	JobType     string          // The job type as string
+	JobPath     dbus.ObjectPath // The job object path
+}
+
 // ListUnits returns an array with all currently loaded units. Note that
 // units may be known by multiple names at the same time, and hence there might
 // be more unit names loaded than actual units behind them.
@@ -250,17 +268,36 @@ func (c *Conn) ListUnits() ([]UnitStatus, error) {
 	return status, nil
 }
 
-type UnitStatus struct {
-	Name        string          // The primary unit name as string
-	Description string          // The human readable description string
-	LoadState   string          // The load state (i.e. whether the unit file has been loaded successfully)
-	ActiveState string          // The active state (i.e. whether the unit is currently started or not)
-	SubState    string          // The sub state (a more fine-grained version of the active state that is specific to the unit type, which the active state is not)
-	Followed    string          // A unit that is being followed in its state by this unit, if there is any, otherwise the empty string.
-	Path        dbus.ObjectPath // The unit object path
-	JobId       uint32          // If there is a job queued for the job unit the numeric job id, 0 otherwise
-	JobType     string          // The job type as string
-	JobPath     dbus.ObjectPath // The job object path
+type UnitFile struct {
+	Path string
+	Type string
+}
+
+// ListUnitFiles returns an array of all available units on disk.
+func (c *Conn) ListUnitFiles() ([]UnitFile, error) {
+	result := make([][]interface{}, 0)
+	err := c.sysobj.Call("org.freedesktop.systemd1.Manager.ListUnitFiles", 0).Store(&result)
+	if err != nil {
+		return nil, err
+	}
+
+	resultInterface := make([]interface{}, len(result))
+	for i := range result {
+		resultInterface[i] = result[i]
+	}
+
+	files := make([]UnitFile, len(result))
+	fileInterface := make([]interface{}, len(files))
+	for i := range files {
+		fileInterface[i] = &files[i]
+	}
+
+	err = dbus.Store(resultInterface, fileInterface...)
+	if err != nil {
+		return nil, err
+	}
+
+	return files, nil
 }
 
 type LinkUnitFileChange EnableUnitFileChange

vendor/github.com/coreos/go-systemd/journal/journal.go

@@ -0,0 +1,179 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package journal provides write bindings to the local systemd journal.
+// It is implemented in pure Go and connects to the journal directly over its
+// unix socket.
+//
+// To read from the journal, see the "sdjournal" package, which wraps the
+// sd-journal a C API.
+//
+// http://www.freedesktop.org/software/systemd/man/systemd-journald.service.html
+package journal
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"syscall"
+)
+
+// Priority of a journal message
+type Priority int
+
+const (
+	PriEmerg Priority = iota
+	PriAlert
+	PriCrit
+	PriErr
+	PriWarning
+	PriNotice
+	PriInfo
+	PriDebug
+)
+
+var conn net.Conn
+
+func init() {
+	var err error
+	conn, err = net.Dial("unixgram", "/run/systemd/journal/socket")
+	if err != nil {
+		conn = nil
+	}
+}
+
+// Enabled returns true if the local systemd journal is available for logging
+func Enabled() bool {
+	return conn != nil
+}
+
+// Send a message to the local systemd journal. vars is a map of journald
+// fields to values.  Fields must be composed of uppercase letters, numbers,
+// and underscores, but must not start with an underscore. Within these
+// restrictions, any arbitrary field name may be used.  Some names have special
+// significance: see the journalctl documentation
+// (http://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html)
+// for more details.  vars may be nil.
+func Send(message string, priority Priority, vars map[string]string) error {
+	if conn == nil {
+		return journalError("could not connect to journald socket")
+	}
+
+	data := new(bytes.Buffer)
+	appendVariable(data, "PRIORITY", strconv.Itoa(int(priority)))
+	appendVariable(data, "MESSAGE", message)
+	for k, v := range vars {
+		appendVariable(data, k, v)
+	}
+
+	_, err := io.Copy(conn, data)
+	if err != nil && isSocketSpaceError(err) {
+		file, err := tempFd()
+		if err != nil {
+			return journalError(err.Error())
+		}
+		defer file.Close()
+		_, err = io.Copy(file, data)
+		if err != nil {
+			return journalError(err.Error())
+		}
+
+		rights := syscall.UnixRights(int(file.Fd()))
+
+		/* this connection should always be a UnixConn, but better safe than sorry */
+		unixConn, ok := conn.(*net.UnixConn)
+		if !ok {
+			return journalError("can't send file through non-Unix connection")
+		}
+		unixConn.WriteMsgUnix([]byte{}, rights, nil)
+	} else if err != nil {
+		return journalError(err.Error())
+	}
+	return nil
+}
+
+// Print prints a message to the local systemd journal using Send().
+func Print(priority Priority, format string, a ...interface{}) error {
+	return Send(fmt.Sprintf(format, a...), priority, nil)
+}
+
+func appendVariable(w io.Writer, name, value string) {
+	if !validVarName(name) {
+		journalError("variable name contains invalid character, ignoring")
+	}
+	if strings.ContainsRune(value, '\n') {
+		/* When the value contains a newline, we write:
+		 * - the variable name, followed by a newline
+		 * - the size (in 64bit little endian format)
+		 * - the data, followed by a newline
+		 */
+		fmt.Fprintln(w, name)
+		binary.Write(w, binary.LittleEndian, uint64(len(value)))
+		fmt.Fprintln(w, value)
+	} else {
+		/* just write the variable and value all on one line */
+		fmt.Fprintf(w, "%s=%s\n", name, value)
+	}
+}
+
+func validVarName(name string) bool {
+	/* The variable name must be in uppercase and consist only of characters,
+	 * numbers and underscores, and may not begin with an underscore. (from the docs)
+	 */
+
+	valid := name[0] != '_'
+	for _, c := range name {
+		valid = valid && ('A' <= c && c <= 'Z') || ('0' <= c && c <= '9') || c == '_'
+	}
+	return valid
+}
+
+func isSocketSpaceError(err error) bool {
+	opErr, ok := err.(*net.OpError)
+	if !ok {
+		return false
+	}
+
+	sysErr, ok := opErr.Err.(syscall.Errno)
+	if !ok {
+		return false
+	}
+
+	return sysErr == syscall.EMSGSIZE || sysErr == syscall.ENOBUFS
+}
+
+func tempFd() (*os.File, error) {
+	file, err := ioutil.TempFile("/dev/shm/", "journal.XXXXX")
+	if err != nil {
+		return nil, err
+	}
+	syscall.Unlink(file.Name())
+	if err != nil {
+		return nil, err
+	}
+	return file, nil
+}
+
+func journalError(s string) error {
+	s = "journal error: " + s
+	fmt.Fprintln(os.Stderr, s)
+	return errors.New(s)
+}

vendor/github.com/coreos/go-systemd/util/util.go

@@ -13,15 +13,197 @@
 // limitations under the License.
 
 // Package util contains utility functions related to systemd that applications
-// can use to check things like whether systemd is running.
+// can use to check things like whether systemd is running.  Note that some of
+// these functions attempt to manually load systemd libraries at runtime rather
+// than linking against them.
 package util
 
+// #include <stdlib.h>
+// #include <sys/types.h>
+// #include <unistd.h>
+//
+// int
+// my_sd_pid_get_owner_uid(void *f, pid_t pid, uid_t *uid)
+// {
+//   int (*sd_pid_get_owner_uid)(pid_t, uid_t *);
+//
+//   sd_pid_get_owner_uid = (int (*)(pid_t, uid_t *))f;
+//   return sd_pid_get_owner_uid(pid, uid);
+// }
+//
+// int
+// my_sd_pid_get_unit(void *f, pid_t pid, char **unit)
+// {
+//   int (*sd_pid_get_unit)(pid_t, char **);
+//
+//   sd_pid_get_unit = (int (*)(pid_t, char **))f;
+//   return sd_pid_get_unit(pid, unit);
+// }
+//
+// int
+// my_sd_pid_get_slice(void *f, pid_t pid, char **slice)
+// {
+//   int (*sd_pid_get_slice)(pid_t, char **);
+//
+//   sd_pid_get_slice = (int (*)(pid_t, char **))f;
+//   return sd_pid_get_slice(pid, slice);
+// }
+//
+// int
+// am_session_leader()
+// {
+//   return (getsid(0) == getpid());
+// }
+import "C"
 import (
+	"fmt"
+	"io/ioutil"
 	"os"
+	"strings"
+	"syscall"
+	"unsafe"
+
+	"github.com/coreos/pkg/dlopen"
 )
 
+var libsystemdNames = []string{
+	// systemd < 209
+	"libsystemd-login.so.0",
+	"libsystemd-login.so",
+
+	// systemd >= 209 merged libsystemd-login into libsystemd proper
+	"libsystemd.so.0",
+	"libsystemd.so",
+}
+
+// GetRunningSlice attempts to retrieve the name of the systemd slice in which
+// the current process is running.
+// This function is a wrapper around the libsystemd C library; if it cannot be
+// opened, an error is returned.
+func GetRunningSlice() (slice string, err error) {
+	var h *dlopen.LibHandle
+	h, err = dlopen.GetHandle(libsystemdNames)
+	if err != nil {
+		return
+	}
+	defer func() {
+		if err1 := h.Close(); err1 != nil {
+			err = err1
+		}
+	}()
+
+	sd_pid_get_slice, err := h.GetSymbolPointer("sd_pid_get_slice")
+	if err != nil {
+		return
+	}
+
+	var s string
+	sl := C.CString(s)
+	defer C.free(unsafe.Pointer(sl))
+
+	ret := C.my_sd_pid_get_slice(sd_pid_get_slice, 0, &sl)
+	if ret < 0 {
+		err = fmt.Errorf("error calling sd_pid_get_slice: %v", syscall.Errno(-ret))
+		return
+	}
+
+	return C.GoString(sl), nil
+}
+
+// RunningFromSystemService tries to detect whether the current process has
+// been invoked from a system service. The condition for this is whether the
+// process is _not_ a user process. User processes are those running in session
+// scopes or under per-user `systemd --user` instances.
+//
+// To avoid false positives on systems without `pam_systemd` (which is
+// responsible for creating user sessions), this function also uses a heuristic
+// to detect whether it's being invoked from a session leader process. This is
+// the case if the current process is executed directly from a service file
+// (e.g. with `ExecStart=/this/cmd`). Note that this heuristic will fail if the
+// command is instead launched in a subshell or similar so that it is not
+// session leader (e.g. `ExecStart=/bin/bash -c "/this/cmd"`)
+//
+// This function is a wrapper around the libsystemd C library; if this is
+// unable to successfully open a handle to the library for any reason (e.g. it
+// cannot be found), an errr will be returned
+func RunningFromSystemService() (ret bool, err error) {
+	var h *dlopen.LibHandle
+	h, err = dlopen.GetHandle(libsystemdNames)
+	if err != nil {
+		return
+	}
+	defer func() {
+		if err1 := h.Close(); err1 != nil {
+			err = err1
+		}
+	}()
+
+	sd_pid_get_owner_uid, err := h.GetSymbolPointer("sd_pid_get_owner_uid")
+	if err != nil {
+		return
+	}
+
+	var uid C.uid_t
+	errno := C.my_sd_pid_get_owner_uid(sd_pid_get_owner_uid, 0, &uid)
+	serrno := syscall.Errno(-errno)
+	// when we're running from a unit file, sd_pid_get_owner_uid returns
+	// ENOENT (systemd <220) or ENXIO (systemd >=220)
+	switch {
+	case errno >= 0:
+		ret = false
+	case serrno == syscall.ENOENT, serrno == syscall.ENXIO:
+		// Since the implementation of sessions in systemd relies on
+		// the `pam_systemd` module, using the sd_pid_get_owner_uid
+		// heuristic alone can result in false positives if that module
+		// (or PAM itself) is not present or properly configured on the
+		// system. As such, we also check if we're the session leader,
+		// which should be the case if we're invoked from a unit file,
+		// but not if e.g. we're invoked from the command line from a
+		// user's login session
+		ret = C.am_session_leader() == 1
+	default:
+		err = fmt.Errorf("error calling sd_pid_get_owner_uid: %v", syscall.Errno(-errno))
+	}
+	return
+}
+
+// CurrentUnitName attempts to retrieve the name of the systemd system unit
+// from which the calling process has been invoked. It wraps the systemd
+// `sd_pid_get_unit` call, with the same caveat: for processes not part of a
+// systemd system unit, this function will return an error.
+func CurrentUnitName() (unit string, err error) {
+	var h *dlopen.LibHandle
+	h, err = dlopen.GetHandle(libsystemdNames)
+	if err != nil {
+		return
+	}
+	defer func() {
+		if err1 := h.Close(); err1 != nil {
+			err = err1
+		}
+	}()
+
+	sd_pid_get_unit, err := h.GetSymbolPointer("sd_pid_get_unit")
+	if err != nil {
+		return
+	}
+
+	var s string
+	u := C.CString(s)
+	defer C.free(unsafe.Pointer(u))
+
+	ret := C.my_sd_pid_get_unit(sd_pid_get_unit, 0, &u)
+	if ret < 0 {
+		err = fmt.Errorf("error calling sd_pid_get_unit: %v", syscall.Errno(-ret))
+		return
+	}
+
+	unit = C.GoString(u)
+	return
+}
+
 // IsRunningSystemd checks whether the host was booted with systemd as its init
-// system. This functions similar to systemd's `sd_booted(3)`: internally, it
+// system. This functions similarly to systemd's `sd_booted(3)`: internally, it
 // checks whether /run/systemd/system/ exists and is a directory.
 // http://www.freedesktop.org/software/systemd/man/sd_booted.html
 func IsRunningSystemd() bool {
@@ -31,3 +213,15 @@ func IsRunningSystemd() bool {
 	}
 	return fi.IsDir()
 }
+
+// GetMachineID returns a host's 128-bit machine ID as a string. This functions
+// similarly to systemd's `sd_id128_get_machine`: internally, it simply reads
+// the contents of /etc/machine-id
+// http://www.freedesktop.org/software/systemd/man/sd_id128_get_machine.html
+func GetMachineID() (string, error) {
+	machineID, err := ioutil.ReadFile("/etc/machine-id")
+	if err != nil {
+		return "", fmt.Errorf("failed to read /etc/machine-id: %v", err)
+	}
+	return strings.TrimSpace(string(machineID)), nil
+}