added pid files. permission denied error

pkg/node/node.go

@@ -2,15 +2,19 @@
 package node
 
 import (
+	"bufio"
 	"context"
 	"errors"
 	"fmt"
+	"github.com/skycoin/skywire/pkg/util/pathutil"
 	"io"
 	"net"
 	"net/rpc"
 	"os"
 	"os/exec"
 	"path/filepath"
+	"strconv"
+	"strings"
 	"sync"
 	"syscall"
 	"time"
@@ -151,6 +155,7 @@ func NewNode(config *Config) (*Node, error) {
 		RoutingTable:     node.rt,
 		RouteFinder:      routeFinder.NewHTTP(config.Routing.RouteFinder, time.Duration(config.Routing.RouteFinderTimeout)),
 		SetupNodes:       config.Routing.SetupNodes,
+
 	}
 	r := router.New(rConfig)
 	node.router = r
@@ -203,6 +208,8 @@ func (node *Node) Start() error {
 	}
 	node.logger.Info("Connected to messaging servers")
 
+	pathutil.EnsureDir(node.dir())
+	node.closePreviousApps()
 	for _, ac := range node.appsConf {
 		if !ac.AutoStart {
 			continue
@@ -239,6 +246,58 @@ func (node *Node) Start() error {
 	return nil
 }
 
+func (node *Node) dir() string {
+	return pathutil.NodeDir(node.config.Node.StaticPubKey)
+}
+
+func (node *Node) pidFile() *os.File {
+	f, err := os.OpenFile(filepath.Join(node.dir(),"apps.pid"), os.O_RDWR|os.O_CREATE, 0755)
+	if err != nil {
+		panic(err)
+	}
+
+	return f
+}
+
+func (node *Node) closePreviousApps() {
+	pids := node.pidFile()
+	defer pids.Close() // nocheck: err
+
+	scanner := bufio.NewScanner(pids)
+	for scanner.Scan() {
+		appInfo := strings.Split(scanner.Text(), " ")
+		if len(appInfo) != 2 {
+			node.logger.Fatal("error parsing %s. Err: %s", pids.Name(), errors.New("line should be: [app name] [pid]"))
+		}
+
+		pid, err := strconv.Atoi(appInfo[1])
+		if err != nil {
+			node.logger.Fatal("error parsing %s. Err: %s", pids.Name(), err)
+		}
+
+		node.stopUnhandledApp(appInfo[0], pid)
+	}
+
+	// empty file
+	pathutil.AtomicWriteFile(pids.Name(), []byte{})
+}
+
+func (node *Node) stopUnhandledApp(name string, pid int) {
+	p, err := os.FindProcess(pid)
+	if err != nil {
+		node.logger.Infof("Previous app %s ran by this node with pid: %d not found", name, pid)
+		return
+	}
+
+	err = p.Signal(syscall.SIGKILL)
+	if err != nil {
+		node.logger.Warnf("Found hanged app %s with pid %d previously ran by this node, but unable to kill it: %s", name, pid, err)
+		return
+	}
+
+	node.logger.Infof("Found and killed hanged app %s with pid %d previously ran by this node", name, pid)
+}
+
 // Close safely stops spawned Apps and messaging Node.
 func (node *Node) Close() (err error) {
 	if node.rpcListener != nil {
@@ -357,6 +416,8 @@ func (node *Node) SpawnApp(config *AppConfig, startCh chan<- struct{}) error {
 		bind.pid = pid
 		node.startedMu.Unlock()
 		appCh <- node.executer.Wait(cmd)
+
+		node.persistPID(config.App, pid)
 	}()
 
 	srvCh := make(chan error)
@@ -389,6 +450,11 @@ func (node *Node) SpawnApp(config *AppConfig, startCh chan<- struct{}) error {
 	return appErr
 }
 
+func (node *Node) persistPID(name string, pid int) {
+	pidF := node.pidFile()
+	pathutil.AtomicAppendToFile(pidF.Name(), []byte(fmt.Sprintf("%s %d\n", name, pid)))
+}
+
 // StopApp stops running App.
 func (node *Node) StopApp(appName string) error {
 	node.startedMu.Lock()
@@ -445,6 +511,7 @@ func (exc *osExecuter) Start(cmd *exec.Cmd) (int, error) {
 	exc.mu.Lock()
 	exc.processes = append(exc.processes, cmd.Process)
 	exc.mu.Unlock()
+
 	return cmd.Process.Pid, nil
 }
 
@@ -457,7 +524,7 @@ func (exc *osExecuter) Stop(pid int) (err error) {
 			continue
 		}
 
-		if sigErr := process.Signal(syscall.SIGTERM); sigErr != nil && err == nil {
+		if sigErr := process.Signal(syscall.SIGKILL); sigErr != nil && err == nil {
 			err = sigErr
 		}
 	}

pkg/router/app_manager.go

@@ -3,9 +3,7 @@ package router
 import (
 	"encoding/json"
 	"errors"
-
 	"github.com/skycoin/skycoin/src/util/logging"
-
 	"github.com/skycoin/skywire/pkg/app"
 )
 
@@ -97,3 +95,4 @@ func (am *appManager) forwardAppPacket(payload []byte) error {
 
 	return am.callbacks.Forward(am.proto, packet)
 }
+

pkg/util/pathutil/homedir.go

@@ -1,7 +1,12 @@
 package pathutil
 
 import (
+	"fmt"
+	"github.com/skycoin/skywire/pkg/cipher"
+	"io/ioutil"
 	"os"
+	"path"
+	"path/filepath"
 	"runtime"
 )
 
@@ -17,3 +22,60 @@ func HomeDir() string {
 	}
 	return os.Getenv("HOME")
 }
+
+// NodeDir returns a path to a directory used to store specific node configuration. Such dir is ~/.skywire/{PK}
+func NodeDir(pk cipher.PubKey) string {
+	return filepath.Join(HomeDir(),".skycoin","skywire",pk.String())
+}
+
+// EnsureDir attempts to create given directory, panics if it fails to do so
+func EnsureDir(path string) {
+	if _, err := os.Stat(path); os.IsNotExist(err) {
+		err := os.MkdirAll(path, 0644)
+		if err != nil {
+			panic(err)
+		}
+	}
+}
+
+// AtomicWriteFile creates a temp file in which to write data, then calls syscall.Rename to swap it and write it on
+// filename for an atomic write. On failure temp file is removed and panics.
+func AtomicWriteFile(filename string, data []byte) {
+	fmt.Println("got filename: ", filename)
+	dir, name := path.Split(filename)
+	f, err := ioutil.TempFile(dir, name)
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = f.Write(data)
+	if err == nil {
+		err = f.Sync()
+	}
+	if closeErr := f.Close(); err == nil {
+		err = closeErr
+	}
+	if permErr := os.Chmod(f.Name(), 0644); err == nil {
+		err = permErr
+	}
+	if err == nil {
+		err = os.Rename(f.Name(), filename)
+	}
+
+	if err != nil {
+		os.Remove(f.Name())
+	}
+	panic(err)
+}
+
+// AtomicAppendToFile calls AtomicWriteFile but appends new data to destiny file
+func AtomicAppendToFile(filename string, data []byte) {
+	fmt.Println("got filename: ", filename)
+	oldFile, err := ioutil.ReadFile(filename)
+	if err != nil {
+		panic(err)
+	}
+
+	AtomicWriteFile(filename, append(oldFile, data...))
+}
+