diff options
| -rw-r--r-- | sd_daemon/notify.go | 95 | ||||
| -rw-r--r-- | sd_daemon/notify_linux.go | 114 | ||||
| -rw-r--r-- | sd_daemon/notify_nonlinux.go | 49 |
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") }() } |