From 0c2e5f13516992e56133647cea4129733eee3fa5 Mon Sep 17 00:00:00 2001
From: MickaelK <mickael@kerjean.me>
Date: Wed, 10 Jan 2024 18:32:37 +1100
Subject: [PATCH] feature (plg_backend_nfs): add option to calculate uid/gid

---
 server/plugin/plg_backend_nfs/index.go | 99 ++++++++++++++++++++------
 1 file changed, 78 insertions(+), 21 deletions(-)

diff --git a/server/plugin/plg_backend_nfs/index.go b/server/plugin/plg_backend_nfs/index.go
index 700cdbbe..53eb55ba 100644
--- a/server/plugin/plg_backend_nfs/index.go
+++ b/server/plugin/plg_backend_nfs/index.go
@@ -1,17 +1,25 @@
 package plg_backend_nfs
 
 import (
+	"bufio"
 	"context"
-	. "github.com/mickael-kerjean/filestash/server/common"
-	"github.com/vmware/go-nfs-client/nfs"
-	"github.com/vmware/go-nfs-client/nfs/rpc"
-	"github.com/vmware/go-nfs-client/nfs/util"
-	"github.com/vmware/go-nfs-client/nfs/xdr"
 	"io"
 	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
+
+	. "github.com/mickael-kerjean/filestash/server/common"
+
+	"github.com/vmware/go-nfs-client/nfs"
+	"github.com/vmware/go-nfs-client/nfs/rpc"
+	"github.com/vmware/go-nfs-client/nfs/util"
+	"github.com/vmware/go-nfs-client/nfs/xdr"
+)
+
+const (
+	DEFAULT_UID = 1000
+	DEFAULT_GID = 1000
 )
 
 type NfsShare struct {
@@ -26,29 +34,20 @@ type NfsShare struct {
 func init() {
 	Backend.Register("nfs", NfsShare{})
 	util.DefaultLogger.SetDebug(false)
+	cacheForEtc = NewAppCache(120, 60)
 }
 
 func (this NfsShare) Init(params map[string]string, app *App) (IBackend, error) {
 	if params["hostname"] == "" {
 		return nil, ErrNotFound
 	}
-	var (
-		uid uint32 = 1000
-		gid uint32 = 1000
-	)
-	if params["uid"] != "" {
-		if _uid, err := strconv.Atoi(params["uid"]); err == nil {
-			uid = uint32(_uid)
-		}
-	}
-	if params["gid"] != "" {
-		if _gid, err := strconv.Atoi(params["gid"]); err == nil {
-			gid = uint32(_gid)
-		}
-	}
+
 	if params["machine_name"] == "" {
 		params["machine_name"] = "filestash"
 	}
+
+	uid := getUid(params["uid"])
+	gid := getGid(params["gid"])
 	auth := rpc.NewAuthUnix(params["machine_name"], uid, gid).Auth()
 	mount, err := nfs.DialMount(params["hostname"])
 	if err != nil {
@@ -88,13 +87,13 @@ func (this NfsShare) LoginForm() Form {
 			FormElement{
 				Id:          "nfs_uid",
 				Name:        "uid",
-				Type:        "number",
+				Type:        "text",
 				Placeholder: "uid",
 			},
 			FormElement{
 				Id:          "nfs_gid",
 				Name:        "gid",
-				Type:        "number",
+				Type:        "text",
 				Placeholder: "gid",
 			},
 			FormElement{
@@ -272,3 +271,61 @@ func (this NfsShare) Close() {
 func (this NfsShare) nfsPath(path string) string {
 	return strings.TrimSuffix(path, "/")
 }
+
+func getUid(hint string) uint32 {
+	if hint == "" {
+		return DEFAULT_UID
+	} else if _uid, err := strconv.Atoi(hint); err == nil {
+		return uint32(_uid)
+	} else if uid, _, err := extractFromEtcPasswd(hint); err == nil {
+		return uid
+	}
+	return DEFAULT_UID
+}
+func getGid(hint string) uint32 {
+	if hint == "" {
+		return DEFAULT_UID
+	} else if _gid, err := strconv.Atoi(hint); err == nil {
+		return uint32(_gid)
+	} else if _, gid, err := extractFromEtcPasswd(hint); err == nil {
+		return gid
+	}
+	return DEFAULT_GID
+}
+
+var cacheForEtc AppCache
+
+func extractFromEtcPasswd(username string) (uint32, uint32, error) {
+	if v := cacheForEtc.Get(map[string]string{"username": username}); v != nil {
+		inCache := v.([]int)
+		return uint32(inCache[0]), uint32(inCache[1]), nil
+	}
+	f, err := os.OpenFile("/etc/passwd", os.O_RDONLY, os.ModePerm)
+	if err != nil {
+		return DEFAULT_UID, DEFAULT_GID, err
+	}
+	defer f.Close()
+	lines := bufio.NewReader(f)
+	for {
+		line, _, err := lines.ReadLine()
+		if err != nil {
+			break
+		}
+		s := strings.Split(string(line), ":")
+		if len(s) != 7 {
+			continue
+		} else if username == s[0] {
+			u, err := strconv.Atoi(s[2])
+			if err != nil {
+				continue
+			}
+			g, err := strconv.Atoi(s[3])
+			if err != nil {
+				continue
+			}
+			cacheForEtc.Set(map[string]string{"username": username}, []int{u, g})
+			return uint32(u), uint32(g), nil
+		}
+	}
+	return DEFAULT_UID, DEFAULT_GID, ErrNotFound
+}