forked from snapcore/snapd
/
daemon.go
264 lines (220 loc) · 5.58 KB
/
daemon.go
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// -*- Mode: Go; indent-tabs-mode: t -*-
/*
* Copyright (C) 2015-2016 Canonical Ltd
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 3 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
package daemon
import (
"fmt"
"net"
"net/http"
"strings"
"time"
"github.com/coreos/go-systemd/activation"
"github.com/gorilla/mux"
"gopkg.in/tomb.v2"
"github.com/snapcore/snapd/logger"
"github.com/snapcore/snapd/notifications"
"github.com/snapcore/snapd/osutil"
"github.com/snapcore/snapd/overlord"
"github.com/snapcore/snapd/overlord/auth"
)
// A Daemon listens for requests and routes them to the right command
type Daemon struct {
Version string
overlord *overlord.Overlord
listener net.Listener
tomb tomb.Tomb
router *mux.Router
hub *notifications.Hub
// enableInternalInterfaceActions controls if adding and removing slots and plugs is allowed.
enableInternalInterfaceActions bool
}
// A ResponseFunc handles one of the individual verbs for a method
type ResponseFunc func(*Command, *http.Request, *auth.UserState) Response
// A Command routes a request to an individual per-verb ResponseFUnc
type Command struct {
Path string
//
GET ResponseFunc
PUT ResponseFunc
POST ResponseFunc
DELETE ResponseFunc
// can sudoer do stuff?
SudoerOK bool
// can guest GET?
GuestOK bool
// can non-admin GET?
UserOK bool
//
d *Daemon
}
var isUIDInAny = osutil.IsUIDInAny
func (c *Command) canAccess(r *http.Request, user *auth.UserState) bool {
if user != nil {
// Authenticated users do anything for now.
return true
}
isUser := false
if uid, err := ucrednetGetUID(r.RemoteAddr); err == nil {
if uid == 0 {
// Superuser does anything.
return true
}
if c.SudoerOK && isUIDInAny(uid, "sudo", "admin", "wheel") {
// If user is in a group that grants sudo in
// the default install, and the command says
// that's ok, then it's ok.
return true
}
isUser = true
}
if r.Method != "GET" {
return false
}
if isUser && c.UserOK {
return true
}
if c.GuestOK {
return true
}
return false
}
func (c *Command) ServeHTTP(w http.ResponseWriter, r *http.Request) {
state := c.d.overlord.State()
state.Lock()
// TODO Look at the error and fail if there's an attempt to authenticate with invalid data.
user, _ := UserFromRequest(state, r)
state.Unlock()
if !c.canAccess(r, user) {
rsp := &resp{
Type: ResponseTypeError,
Result: &errorResult{
Message: "access denied",
Kind: errorKindLoginRequired,
},
Status: http.StatusUnauthorized,
}
rsp.ServeHTTP(w, r)
return
}
var rspf ResponseFunc
var rsp = BadMethod("method %q not allowed", r.Method)
switch r.Method {
case "GET":
rspf = c.GET
case "PUT":
rspf = c.PUT
case "POST":
rspf = c.POST
case "DELETE":
rspf = c.DELETE
}
if rspf != nil {
rsp = rspf(c, r, user)
}
rsp.ServeHTTP(w, r)
}
type wrappedWriter struct {
w http.ResponseWriter
s int
}
func (w *wrappedWriter) Header() http.Header {
return w.w.Header()
}
func (w *wrappedWriter) Write(bs []byte) (int, error) {
return w.w.Write(bs)
}
func (w *wrappedWriter) WriteHeader(s int) {
w.w.WriteHeader(s)
w.s = s
}
func logit(handler http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
ww := &wrappedWriter{w: w}
t0 := time.Now()
handler.ServeHTTP(ww, r)
t := time.Now().Sub(t0)
url := r.URL.String()
if !strings.Contains(url, "/changes/") {
logger.Debugf("%s %s %s %s %d", r.RemoteAddr, r.Method, r.URL, t, ww.s)
}
})
}
// Init sets up the Daemon's internal workings.
// Don't call more than once.
func (d *Daemon) Init() error {
t0 := time.Now()
listeners, err := activation.Listeners(false)
if err != nil {
return err
}
if len(listeners) != 1 {
return fmt.Errorf("daemon does not handle %d listeners right now, just one", len(listeners))
}
d.listener = &ucrednetListener{listeners[0]}
d.addRoutes()
logger.Debugf("init done in %s", time.Now().Sub(t0))
return nil
}
func (d *Daemon) addRoutes() {
d.router = mux.NewRouter()
for _, c := range api {
c.d = d
logger.Debugf("adding %s", c.Path)
d.router.Handle(c.Path, c).Name(c.Path)
}
// also maybe add a /favicon.ico handler...
d.router.NotFoundHandler = NotFound("not found")
}
// Start the Daemon
func (d *Daemon) Start() {
// die when asked to restart (systemd should get us back up!)
d.overlord.SetRestartHandler(func() {
d.tomb.Kill(nil)
})
// the loop runs in its own goroutine
d.overlord.Loop()
d.tomb.Go(func() error {
if err := http.Serve(d.listener, logit(d.router)); err != nil && d.tomb.Err() == tomb.ErrStillAlive {
return err
}
return nil
})
}
// Stop shuts down the Daemon
func (d *Daemon) Stop() error {
d.tomb.Kill(nil)
d.listener.Close()
d.overlord.Stop()
return d.tomb.Wait()
}
// Dying is a tomb-ish thing
func (d *Daemon) Dying() <-chan struct{} {
return d.tomb.Dying()
}
// New Daemon
func New() (*Daemon, error) {
ovld, err := overlord.New()
if err != nil {
return nil, err
}
return &Daemon{
overlord: ovld,
hub: notifications.NewHub(),
// TODO: Decide when this should be disabled by default.
enableInternalInterfaceActions: true,
}, nil
}