Fork of store into another process

First working prototype of an own process serving the store over the
previously implemented RPC. So far no privilege separation was
performed, but now it can be build on top of it.

gosh.go

@@ -1,11 +1,14 @@
 package main
 
 import (
+	"bufio"
 	"flag"
 	"net"
 	"net/http"
 	"net/http/fcgi"
 	"os"
+	"os/exec"
+	"os/signal"
 	"strings"
 	"time"
 
@@ -50,10 +53,40 @@ func serveHttpd(server *Server) {
 	}
 }
 
+func mainStore(storePath string) {
+	log.WithField("store", storePath).Info("Starting store child")
+
+	store, err := NewStore(storePath, true)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	rpcConn, err := UnixConnFromFile(os.NewFile(3, ""))
+	if err != nil {
+		log.Fatal(err)
+	}
+	fdConn, err := UnixConnFromFile(os.NewFile(4, ""))
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	rpcStore := NewStoreRpcServer(store, rpcConn, fdConn)
+
+	sigint := make(chan os.Signal, 1)
+	signal.Notify(sigint, os.Interrupt)
+	<-sigint
+
+	err = rpcStore.Close()
+	if err != nil {
+		log.Fatal(err)
+	}
+}
+
 func main() {
 	log.SetFormatter(&log.TextFormatter{DisableTimestamp: true})
 
 	var (
+		forkStore      bool
 		maxLifetimeStr string
 		maxFilesizeStr string
 		mimeMapStr     string
@@ -62,7 +95,10 @@ func main() {
 		verbose        bool
 	)
 
+	log.WithField("args", os.Args).Info("args")
+
 	flag.StringVar(&storePath, "store", "", "Path to the store")
+	flag.BoolVar(&forkStore, "fork-store", false, "Start the store sub")
 	flag.StringVar(&maxFilesizeStr, "max-filesize", "10MiB", "Maximum file size in bytes")
 	flag.StringVar(&maxLifetimeStr, "max-lifetime", "24h", "Maximum lifetime")
 	flag.StringVar(&contactMail, "contact", "", "Contact E-Mail for abuses")
@@ -79,6 +115,11 @@ func main() {
 		log.SetLevel(log.DebugLevel)
 	}
 
+	if forkStore {
+		mainStore(storePath)
+		return
+	}
+
 	if lt, err := ParseDuration(maxLifetimeStr); err != nil {
 		log.WithError(err).Fatal("Failed to parse lifetime")
 	} else {
@@ -98,6 +139,56 @@ func main() {
 		log.Fatal("Contact information must be set, see `--help`")
 	}
 
+	logParent, logStore, err := Socketpair()
+	if err != nil {
+		log.Fatal(err)
+	}
+	rpcParent, rpcStore, err := Socketpair()
+	if err != nil {
+		log.Fatal(err)
+	}
+	fdParent, fdStore, err := Socketpair()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	go func() {
+		scanner := bufio.NewScanner(logParent)
+		for scanner.Scan() {
+			log.Printf("[store] %s", scanner.Text())
+			if err := scanner.Err(); err != nil {
+				log.Printf("scanner failed: %v", err)
+			}
+		}
+	}()
+
+	cmd := &exec.Cmd{
+		Path: os.Args[0],
+		Args: append(os.Args, "-fork-store"),
+
+		Env: []string{},
+
+		Stdin:      nil,
+		Stdout:     logStore,
+		Stderr:     logStore,
+		ExtraFiles: []*os.File{rpcStore, fdStore},
+	}
+	err = cmd.Start()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	rpcConn, err := UnixConnFromFile(rpcParent)
+	if err != nil {
+		log.Fatal(err)
+	}
+	fdConn, err := UnixConnFromFile(fdParent)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	storeClient := NewStoreRpcClient(rpcConn, fdConn)
+
 	hardeningOpts := &HardeningOpts{
 		StoreDir: &storePath,
 	}
@@ -131,7 +222,7 @@ func main() {
 		}
 	}
 
-	server, err := NewServer(storePath, maxFilesize, maxLifetime, contactMail, mimeMap, urlPrefix)
+	server, err := NewServer(storeClient, maxFilesize, maxLifetime, contactMail, mimeMap, urlPrefix)
 	if err != nil {
 		log.WithError(err).Fatal("Failed to start Store")
 	}

server.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"context"
 	"fmt"
 	"io"
 	"net/http"
@@ -171,7 +172,7 @@ const (
 
 // Server implements an http.Handler for up- and download.
 type Server struct {
-	store       *Store
+	store       *StoreRpcClient
 	maxSize     int64
 	maxLifetime time.Duration
 	contactMail string
@@ -181,14 +182,8 @@ type Server struct {
 
 // NewServer creates a new Server with a given database directory, and
 // configuration values. The Server must be started as an http.Handler.
-func NewServer(storeDirectory string, maxSize int64, maxLifetime time.Duration,
+func NewServer(store *StoreRpcClient, maxSize int64, maxLifetime time.Duration,
 	contactMail string, mimeMap MimeMap, urlPrefix string) (s *Server, err error) {
-	store, storeErr := NewStore(storeDirectory, true)
-	if storeErr != nil {
-		err = storeErr
-		return
-	}
-
 	s = &Server{
 		store:       store,
 		maxSize:     maxSize,
@@ -292,7 +287,7 @@ func (serv *Server) handleUpload(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	itemId, err := serv.store.Put(item, f)
+	itemId, err := serv.store.Put(item, f, context.Background())
 	if err != nil {
 		log.WithError(err).Error("Failed to store Item")
 
@@ -333,7 +328,7 @@ func (serv *Server) hasClientCachedRequest(r *http.Request, item Item) bool {
 
 // handleRequestServe is called from handleRequest when a valid Item should be served.
 func (serv *Server) handleRequestServe(w http.ResponseWriter, r *http.Request, item Item) error {
-	f, err := serv.store.GetFile(item.ID)
+	f, err := serv.store.GetFile(item.ID, context.Background())
 	if err != nil {
 		return fmt.Errorf("reading file failed: %v", err)
 	}
@@ -371,7 +366,7 @@ func (serv *Server) handleRequest(w http.ResponseWriter, r *http.Request) {
 	_, reqId, _ := strings.Cut(r.URL.Path, serv.urlPrefix)
 	reqId = strings.TrimLeft(reqId, "/")
 
-	item, err := serv.store.Get(reqId)
+	item, err := serv.store.Get(reqId, context.Background())
 	if err == ErrNotFound {
 		log.WithField("ID", reqId).Debug("Requested non-existing ID")
 
@@ -401,7 +396,7 @@ func (serv *Server) handleRequest(w http.ResponseWriter, r *http.Request) {
 
 	if item.BurnAfterReading {
 		log.WithField("ID", item.ID).Info("Item will be burned")
-		if err := serv.store.Delete(item.ID); err != nil {
+		if err := serv.store.Delete(item.ID, context.Background()); err != nil {
 			log.WithError(err).WithField("ID", item.ID).Error("Deletion failed")
 		}
 	}
@@ -428,7 +423,7 @@ func (serv *Server) handleDeletion(w http.ResponseWriter, r *http.Request) {
 
 	reqId, delKey := reqParts[1], reqParts[2]
 
-	item, err := serv.store.Get(reqId)
+	item, err := serv.store.Get(reqId, context.Background())
 	if err == ErrNotFound {
 		log.WithField("ID", reqId).Debug("Requested non-existing ID")
 
@@ -448,7 +443,7 @@ func (serv *Server) handleDeletion(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	if err := serv.store.Delete(item.ID); err != nil {
+	if err := serv.store.Delete(item.ID, context.Background()); err != nil {
 		log.WithError(err).WithField("ID", reqId).Error("Requested deletion failed")
 
 		http.Error(w, msgGenericError, http.StatusBadRequest)