Unify notify.go and notify_nonlinux.go a bit

3 files changed, 123 insertions, 135 deletions

diff --git a/sd_daemon/notify.go b/sd_daemon/notify.go
index 917e2d4..9591613 100644
--- a/sd_daemon/notify.go
+++ b/sd_daemon/notify.go
@@ -3,7 +3,7 @@
 //
 // Copyright 2013, 2015 Docker, Inc.
 // Copyright 2014 CoreOS, Inc.
-// Copyright 2015-2018 Luke Shumaker
+// Copyright 2015-2019 Luke Shumaker
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -17,16 +17,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-// +build linux
-
 package sd_daemon
 
 import (
-	"bytes"
-	"net"
 	"os"
-
-	"golang.org/x/sys/unix"
 )
 
 // Notification is a message to be sent to the service manager about
@@ -36,6 +30,11 @@ type Notification struct {
 	// If PID <= 0, or if the current process does not have
 	// privileges to send messages on behalf of other processes,
 	// then the message is simply sent from the current process.
+	//
+	// BUG(lukeshu): Spoofing the PID is not implemented on
+	// non-Linux kernels.  If you are knowledgable about how to do
+	// this on other kernels, please let me know at
+	// <lukeshu@lukeshu.com>!
 	PID int
 
 	// State should contain a newline-separated list of variable
@@ -75,85 +74,5 @@ type Notification struct {
 // support both service managers that support these notifications and
 // those that do not.
 func (msg Notification) Send(unsetEnv bool) error {
-	if unsetEnv {
-		defer func() { _ = os.Unsetenv("NOTIFY_SOCKET") }()
-	}
-
-	socketAddr := &net.UnixAddr{
-		Name: os.Getenv("NOTIFY_SOCKET"),
-		Net:  "unixgram",
-	}
-
-	if socketAddr.Name == "" {
-		return ErrDisabled
-	}
-
-	conn, err := socketUnixgram(socketAddr.Name)
-	if err != nil {
-		return err
-	}
-	defer func() { _ = conn.Close() }()
-
-	var cmsgs [][]byte
-
-	if len(msg.Files) > 0 {
-		fds := make([]int, len(msg.Files))
-		for i := range msg.Files {
-			fds[i] = int(msg.Files[i].Fd())
-		}
-		cmsg := unix.UnixRights(fds...)
-		cmsgs = append(cmsgs, cmsg)
-	}
-
-	havePid := msg.PID > 0 && msg.PID != os.Getpid()
-	if havePid {
-		cmsg := unix.UnixCredentials(&unix.Ucred{
-			Pid: int32(msg.PID),
-			Uid: uint32(os.Getuid()),
-			Gid: uint32(os.Getgid()),
-		})
-		cmsgs = append(cmsgs, cmsg)
-	}
-
-	// If the 2nd argument is empty, this is equivalent to
-	//
-	//    conn, _ := net.DialUnix(socketAddr.Net, nil, socketAddr)
-	//    conn.Write([]byte(msg.State))
-	_, _, err = conn.WriteMsgUnix([]byte(msg.State), bytes.Join(cmsgs, nil), socketAddr)
-
-	if err != nil && havePid {
-		// Maybe it failed because we don't have privileges to
-		// spoof our pid; retry without spoofing the pid.
-		//
-		// I'm not too happy that we do this silently without
-		// notifying the caller, but that's what
-		// sd_pid_notify_with_fds does.
-		cmsgs = cmsgs[:len(cmsgs)-1]
-		_, _, err = conn.WriteMsgUnix([]byte(msg.State), bytes.Join(cmsgs, nil), socketAddr)
-	}
-
-	return err
-}
-
-// socketUnixgram wraps socket(2), but doesn't bind(2) or connect(2)
-// the socket to anything.  This is an ugly hack because none of the
-// functions in "net" actually allow you to get a AF_UNIX socket not
-// bound/connected to anything.
-//
-// At some point you begin to question if it is worth it to keep up
-// the high-level interface of "net", and messing around with FileConn
-// and UnixConn.  Maybe we just drop to using unix.Socket and
-// unix.SendmsgN directly.
-func socketUnixgram(name string) (*net.UnixConn, error) {
-	fd, err := unix.Socket(unix.AF_UNIX, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC, 0)
-	if err != nil {
-		return nil, os.NewSyscallError("socket", err)
-	}
-	defer unix.Close(fd)
-	conn, err := net.FileConn(os.NewFile(uintptr(fd), name))
-	if err != nil {
-		return nil, err
-	}
-	unixConn := conn.(*net.UnixConn)
-	return unixConn, nil
+	return msg.send(unsetEnv)
 }
diff --git a/sd_daemon/notify_linux.go b/sd_daemon/notify_linux.go
new file mode 100644
index 0000000..903f1ad
--- /dev/null
+++ b/sd_daemon/notify_linux.go
@@ -0,0 +1,114 @@
+// Incorporates: git://github.com/docker/docker.git 18c7c67308bd4a24a41028e63c2603bb74eac85e pkg/systemd/sd_notify.go
+// Incorporates: git://github.com/coreos/go-systemd.git a606a1e936df81b70d85448221c7b1c6d8a74ef1 daemon/sdnotify.go
+//
+// Copyright 2013, 2015 Docker, Inc.
+// Copyright 2014 CoreOS, Inc.
+// Copyright 2015-2019 Luke Shumaker
+//
+// 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.
+
+// +build linux
+
+package sd_daemon
+
+import (
+	"bytes"
+	"net"
+	"os"
+
+	"golang.org/x/sys/unix"
+)
+
+func (msg Notification) send(unsetEnv bool) error {
+	if unsetEnv {
+		defer func() { _ = os.Unsetenv("NOTIFY_SOCKET") }()
+	}
+
+	socketAddr := &net.UnixAddr{
+		Name: os.Getenv("NOTIFY_SOCKET"),
+		Net:  "unixgram",
+	}
+
+	if socketAddr.Name == "" {
+		return ErrDisabled
+	}
+
+	conn, err := socketUnixgram(socketAddr.Name)
+	if err != nil {
+		return err
+	}
+	defer func() { _ = conn.Close() }()
+
+	var cmsgs [][]byte
+
+	if len(msg.Files) > 0 {
+		fds := make([]int, len(msg.Files))
+		for i := range msg.Files {
+			fds[i] = int(msg.Files[i].Fd())
+		}
+		cmsg := unix.UnixRights(fds...)
+		cmsgs = append(cmsgs, cmsg)
+	}
+
+	havePid := msg.PID > 0 && msg.PID != os.Getpid()
+	if havePid {
+		cmsg := unix.UnixCredentials(&unix.Ucred{
+			Pid: int32(msg.PID),
+			Uid: uint32(os.Getuid()),
+			Gid: uint32(os.Getgid()),
+		})
+		cmsgs = append(cmsgs, cmsg)
+	}
+
+	// If the 2nd argument is empty, this is equivalent to
+	//
+	//    conn, _ := net.DialUnix(socketAddr.Net, nil, socketAddr)
+	//    conn.Write([]byte(msg.State))
+	_, _, err = conn.WriteMsgUnix([]byte(msg.State), bytes.Join(cmsgs, nil), socketAddr)
+
+	if err != nil && havePid {
+		// Maybe it failed because we don't have privileges to
+		// spoof our pid; retry without spoofing the pid.
+		//
+		// I'm not too happy that we do this silently without
+		// notifying the caller, but that's what
+		// sd_pid_notify_with_fds does.
+		cmsgs = cmsgs[:len(cmsgs)-1]
+		_, _, err = conn.WriteMsgUnix([]byte(msg.State), bytes.Join(cmsgs, nil), socketAddr)
+	}
+
+	return err
+}
+
+// socketUnixgram wraps socket(2), but doesn't bind(2) or connect(2)
+// the socket to anything.  This is an ugly hack because none of the
+// functions in "net" actually allow you to get a AF_UNIX socket not
+// bound/connected to anything.
+//
+// At some point you begin to question if it is worth it to keep up
+// the high-level interface of "net", and messing around with FileConn
+// and UnixConn.  Maybe we just drop to using unix.Socket and
+// unix.SendmsgN directly.
+func socketUnixgram(name string) (*net.UnixConn, error) {
+	fd, err := unix.Socket(unix.AF_UNIX, unix.SOCK_DGRAM|unix.SOCK_CLOEXEC, 0)
+	if err != nil {
+		return nil, os.NewSyscallError("socket", err)
+	}
+	defer unix.Close(fd)
+	conn, err := net.FileConn(os.NewFile(uintptr(fd), name))
+	if err != nil {
+		return nil, err
+	}
+	unixConn := conn.(*net.UnixConn)
+	return unixConn, nil
+}
diff --git a/sd_daemon/notify_nonlinux.go b/sd_daemon/notify_nonlinux.go
index 7b37a19..d09cef0 100644
--- a/sd_daemon/notify_nonlinux.go
+++ b/sd_daemon/notify_nonlinux.go
@@ -3,7 +3,7 @@
 //
 // Copyright 2013, 2015 Docker, Inc.
 // Copyright 2014 CoreOS, Inc.
-// Copyright 2015-2018 Luke Shumaker
+// Copyright 2015-2019 Luke Shumaker
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
 // you may not use this file except in compliance with the License.
@@ -30,52 +30,7 @@ import (
 	"golang.org/x/sys/unix"
 )
 
-// Notification is a message to be sent to the service manager about
-// state changes.
-type Notification struct {
-	// PID specifies which process to send a notification about.
-	// If PID <= 0, or if the current process does not have
-	// privileges to send messages on behalf of other processes,
-	// then the message is simply sent from the current process.
-	PID int
-
-	// State should contain a newline-separated list of variable
-	// assignments.  See the documentation for sd_notify(3) for
-	// well-known variable assignments.
-	//
-	// https://www.freedesktop.org/software/systemd/man/sd_notify.html
-	State string
-
-	// Files is a list of file descriptors to send to the service
-	// manager with the message.  This is useful for keeping files
-	// open across restarts, as it enables the service manager to
-	// pass those files to the new process when it is restarted
-	// (see ListenFds).
-	//
-	// Note: The service manager will only actually store the file
-	// descriptors if you include "FDSTORE=1" in the state (again,
-	// see sd_notify(3) for well-known variable assignments).
-	Files []*os.File
-}
-
-// Send sends the Notification to the service manager.
-//
-// If unsetEnv is true, then (regardless of whether the function call
-// itself succeeds or not) it will unset the environmental variable
-// NOTIFY_SOCKET, which will cause further notify operations to fail.
-//
-// If the service manager is not listening for notifications from this
-// process tree (or a Notification has has already been send with
-// unsetEnv=true), then ErrDisabled is returned.  If the service
-// manager appears to be listening, but there is an error sending the
-// message, then that error is returned.
-//
-// It is generally recommended that you ignore the return value: if
-// there is an error, then this is function no-op; meaning that by
-// calling the function but ignoring the return value, you can easily
-// support both service managers that support these notifications and
-// those that do not.
-func (msg Notification) Send(unsetEnv bool) error {
+func (msg Notification) send(unsetEnv bool) error {
 	if unsetEnv {
 		defer func() { _ = os.Unsetenv("NOTIFY_SOCKET") }()
 	}