forked from scionproto/scion
/
main.go
179 lines (161 loc) · 4.43 KB
/
main.go
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// Copyright 2018 ETH Zurich
// Copyright 2019 ETH Zurich, Anapaya Systems
//
// 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 main
import (
"flag"
"fmt"
"net/http"
_ "net/http/pprof"
"os"
"os/user"
"github.com/BurntSushi/toml"
"github.com/scionproto/scion/go/godispatcher/internal/config"
"github.com/scionproto/scion/go/godispatcher/network"
"github.com/scionproto/scion/go/lib/common"
"github.com/scionproto/scion/go/lib/env"
"github.com/scionproto/scion/go/lib/fatal"
"github.com/scionproto/scion/go/lib/log"
"github.com/scionproto/scion/go/lib/prom"
"github.com/scionproto/scion/go/lib/serrors"
"github.com/scionproto/scion/go/lib/util"
)
var (
cfg config.Config
)
func main() {
os.Exit(realMain())
}
func realMain() int {
fatal.Init()
env.AddFlags()
flag.Parse()
if returnCode, ok := env.CheckFlags(&cfg); !ok {
return returnCode
}
if err := setupBasic(); err != nil {
fmt.Fprintln(os.Stderr, err)
return 1
}
defer log.Flush()
defer env.LogAppStopped("Dispatcher", cfg.Dispatcher.ID)
defer log.LogPanicAndExit()
if err := cfg.Validate(); err != nil {
log.Crit("Unable to validate config", "err", err)
return 1
}
if err := checkPerms(); err != nil {
log.Crit("Permissions checks failed", "err", err)
return 1
}
if err := util.CreateParentDirs(cfg.Dispatcher.ApplicationSocket); err != nil {
log.Crit("Unable to create directory tree for socket", "err", err)
return 1
}
go func() {
defer log.LogPanicAndExit()
err := RunDispatcher(
cfg.Dispatcher.DeleteSocket,
cfg.Dispatcher.ApplicationSocket,
os.FileMode(cfg.Dispatcher.SocketFileMode),
cfg.Dispatcher.OverlayPort,
)
if err != nil {
fatal.Fatal(err)
}
}()
if cfg.Dispatcher.PerfData != "" {
go func() {
defer log.LogPanicAndExit()
err := http.ListenAndServe(cfg.Dispatcher.PerfData, nil)
if err != nil {
fatal.Fatal(err)
}
}()
}
env.SetupEnv(nil)
cfg.Metrics.StartPrometheus()
returnCode := waitForTeardown()
// XXX(scrye): if the dispatcher is shut down on purpose, it is usually
// done together with the whole stack on top the dispatcher. Cleaning
// up gracefully does not give us anything in this case. We just clean
// up the sockets and let the application close.
errDelete := deleteSocket(cfg.Dispatcher.ApplicationSocket)
if errDelete != nil {
log.Warn("Unable to delete socket when shutting down", errDelete)
}
switch {
case returnCode != 0:
return returnCode
case errDelete != nil:
return 1
default:
return 0
}
}
func setupBasic() error {
if _, err := toml.DecodeFile(env.ConfigFile(), &cfg); err != nil {
return err
}
cfg.InitDefaults()
if err := env.InitLogging(&cfg.Logging); err != nil {
return err
}
prom.ExportElementID(cfg.Dispatcher.ID)
return env.LogAppStarted("Dispatcher", cfg.Dispatcher.ID)
}
func RunDispatcher(deleteSocketFlag bool, applicationSocket string, socketFileMode os.FileMode,
overlayPort int) error {
if deleteSocketFlag {
if err := deleteSocket(cfg.Dispatcher.ApplicationSocket); err != nil {
return err
}
}
dispatcher := &network.Dispatcher{
RoutingTable: network.NewIATable(1024, 65535),
OverlaySocket: fmt.Sprintf(":%d", overlayPort),
ApplicationSocket: applicationSocket,
SocketFileMode: socketFileMode,
}
log.Debug("Dispatcher starting", "appSocket", applicationSocket, "overlayPort", overlayPort)
return dispatcher.ListenAndServe()
}
func deleteSocket(socket string) error {
if _, err := os.Stat(socket); err != nil {
// File does not exist, or we can't read it, nothing to delete
return nil
}
if err := os.Remove(socket); err != nil {
return err
}
return nil
}
func waitForTeardown() int {
select {
case <-fatal.ShutdownChan():
return 0
case <-fatal.FatalChan():
return 1
}
}
func checkPerms() error {
u, err := user.Current()
if err != nil {
return common.NewBasicError("Error retrieving user", err)
}
if u.Uid == "0" {
return serrors.New("Running as root is not allowed for security reasons")
}
return nil
}