cmd/syncthing: Add debug commands to cli (#7503)

cmd/syncthing/cli/debug.go

@@ -0,0 +1,51 @@
+// Copyright (C) 2021 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package cli
+
+import (
+	"fmt"
+
+	"github.com/urfave/cli"
+)
+
+var debugCommand = cli.Command{
+	Name:     "debug",
+	HideHelp: true,
+	Usage:    "Debug command group",
+	Subcommands: []cli.Command{
+		{
+			Name:      "file",
+			Usage:     "Show information about a file (or directory/symlink)",
+			ArgsUsage: "FOLDER-ID PATH",
+			Action:    expects(2, debugFile()),
+		},
+		indexCommand,
+		{
+			Name:      "profile",
+			Usage:     "Save a profile to help figuring out what Syncthing does.",
+			ArgsUsage: "cpu | heap",
+			Action:    expects(1, profile()),
+		},
+	},
+}
+
+func debugFile() cli.ActionFunc {
+	return func(c *cli.Context) error {
+		return indexDumpOutput(fmt.Sprintf("debug/file?folder=%v&file=%v", c.Args()[0], normalizePath(c.Args()[1])))(c)
+	}
+}
+
+func profile() cli.ActionFunc {
+	return func(c *cli.Context) error {
+		switch t := c.Args()[0]; t {
+		case "cpu", "heap":
+			return saveToFile(fmt.Sprintf("debug/%vprof", c.Args()[0]))(c)
+		default:
+			return fmt.Errorf("expected cpu or heap as argument, got %v", t)
+		}
+	}
+}

cmd/syncthing/cli/errors.go

@@ -22,7 +22,7 @@ var errorsCommand = cli.Command{
 		{
 			Name:   "show",
 			Usage:  "Show pending errors",
-			Action: expects(0, dumpOutput("system/error")),
+			Action: expects(0, indexDumpOutput("system/error")),
 		},
 		{
 			Name:      "push",

cmd/syncthing/cli/index.go

@@ -0,0 +1,38 @@
+// Copyright (C) 2014 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package cli
+
+import (
+	"github.com/urfave/cli"
+)
+
+var indexCommand = cli.Command{
+	Name:  "index",
+	Usage: "Show information about the index (database)",
+	Subcommands: []cli.Command{
+		{
+			Name:   "dump",
+			Usage:  "Print the entire db",
+			Action: expects(0, indexDump),
+		},
+		{
+			Name:   "dump-size",
+			Usage:  "Print the db size of different categories of information",
+			Action: expects(0, indexDumpSize),
+		},
+		{
+			Name:   "check",
+			Usage:  "Check the database for inconsistencies",
+			Action: expects(0, indexCheck),
+		},
+		{
+			Name:   "account",
+			Usage:  "Print key and value size statistics per key type",
+			Action: expects(0, indexAccount),
+		},
+	},
+}

cmd/syncthing/cli/index_accounting.go

@@ -0,0 +1,64 @@
+// Copyright (C) 2020 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package cli
+
+import (
+	"fmt"
+	"os"
+	"text/tabwriter"
+
+	"github.com/urfave/cli"
+)
+
+// indexAccount prints key and data size statistics per class
+func indexAccount(*cli.Context) error {
+	ldb, err := getDB()
+	if err != nil {
+		return err
+	}
+
+	it, err := ldb.NewPrefixIterator(nil)
+	if err != nil {
+		return err
+	}
+
+	var ksizes [256]int
+	var dsizes [256]int
+	var counts [256]int
+	var max [256]int
+
+	for it.Next() {
+		key := it.Key()
+		t := key[0]
+		ds := len(it.Value())
+		ks := len(key)
+		s := ks + ds
+
+		counts[t]++
+		ksizes[t] += ks
+		dsizes[t] += ds
+		if s > max[t] {
+			max[t] = s
+		}
+	}
+
+	tw := tabwriter.NewWriter(os.Stdout, 1, 1, 1, ' ', tabwriter.AlignRight)
+	toti, totds, totks := 0, 0, 0
+	for t := range ksizes {
+		if ksizes[t] > 0 {
+			// yes metric kilobytes 🤘
+			fmt.Fprintf(tw, "0x%02x:\t%d items,\t%d KB keys +\t%d KB data,\t%d B +\t%d B avg,\t%d B max\t\n", t, counts[t], ksizes[t]/1000, dsizes[t]/1000, ksizes[t]/counts[t], dsizes[t]/counts[t], max[t])
+			toti += counts[t]
+			totds += dsizes[t]
+			totks += ksizes[t]
+		}
+	}
+	fmt.Fprintf(tw, "Total\t%d items,\t%d KB keys +\t%d KB data.\t\n", toti, totks/1000, totds/1000)
+	tw.Flush()
+
+	return nil
+}

cmd/syncthing/cli/index_dump.go

@@ -0,0 +1,160 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package cli
+
+import (
+	"encoding/binary"
+	"fmt"
+	"time"
+
+	"github.com/urfave/cli"
+
+	"github.com/syncthing/syncthing/lib/db"
+	"github.com/syncthing/syncthing/lib/protocol"
+)
+
+func indexDump(*cli.Context) error {
+	ldb, err := getDB()
+	if err != nil {
+		return err
+	}
+	it, err := ldb.NewPrefixIterator(nil)
+	if err != nil {
+		return err
+	}
+	for it.Next() {
+		key := it.Key()
+		switch key[0] {
+		case db.KeyTypeDevice:
+			folder := binary.BigEndian.Uint32(key[1:])
+			device := binary.BigEndian.Uint32(key[1+4:])
+			name := nulString(key[1+4+4:])
+			fmt.Printf("[device] F:%d D:%d N:%q", folder, device, name)
+
+			var f protocol.FileInfo
+			err := f.Unmarshal(it.Value())
+			if err != nil {
+				return err
+			}
+			fmt.Printf(" V:%v\n", f)
+
+		case db.KeyTypeGlobal:
+			folder := binary.BigEndian.Uint32(key[1:])
+			name := nulString(key[1+4:])
+			var flv db.VersionList
+			flv.Unmarshal(it.Value())
+			fmt.Printf("[global] F:%d N:%q V:%s\n", folder, name, flv)
+
+		case db.KeyTypeBlock:
+			folder := binary.BigEndian.Uint32(key[1:])
+			hash := key[1+4 : 1+4+32]
+			name := nulString(key[1+4+32:])
+			fmt.Printf("[block] F:%d H:%x N:%q I:%d\n", folder, hash, name, binary.BigEndian.Uint32(it.Value()))
+
+		case db.KeyTypeDeviceStatistic:
+			fmt.Printf("[dstat] K:%x V:%x\n", key, it.Value())
+
+		case db.KeyTypeFolderStatistic:
+			fmt.Printf("[fstat] K:%x V:%x\n", key, it.Value())
+
+		case db.KeyTypeVirtualMtime:
+			folder := binary.BigEndian.Uint32(key[1:])
+			name := nulString(key[1+4:])
+			val := it.Value()
+			var realTime, virtualTime time.Time
+			realTime.UnmarshalBinary(val[:len(val)/2])
+			virtualTime.UnmarshalBinary(val[len(val)/2:])
+			fmt.Printf("[mtime] F:%d N:%q R:%v V:%v\n", folder, name, realTime, virtualTime)
+
+		case db.KeyTypeFolderIdx:
+			key := binary.BigEndian.Uint32(key[1:])
+			fmt.Printf("[folderidx] K:%d V:%q\n", key, it.Value())
+
+		case db.KeyTypeDeviceIdx:
+			key := binary.BigEndian.Uint32(key[1:])
+			val := it.Value()
+			device := "<nil>"
+			if len(val) > 0 {
+				dev, err := protocol.DeviceIDFromBytes(val)
+				if err != nil {
+					device = fmt.Sprintf("<invalid %d bytes>", len(val))
+				} else {
+					device = dev.String()
+				}
+			}
+			fmt.Printf("[deviceidx] K:%d V:%s\n", key, device)
+
+		case db.KeyTypeIndexID:
+			device := binary.BigEndian.Uint32(key[1:])
+			folder := binary.BigEndian.Uint32(key[5:])
+			fmt.Printf("[indexid] D:%d F:%d I:%x\n", device, folder, it.Value())
+
+		case db.KeyTypeFolderMeta:
+			folder := binary.BigEndian.Uint32(key[1:])
+			fmt.Printf("[foldermeta] F:%d", folder)
+			var cs db.CountsSet
+			if err := cs.Unmarshal(it.Value()); err != nil {
+				fmt.Printf(" (invalid)\n")
+			} else {
+				fmt.Printf(" V:%v\n", cs)
+			}
+
+		case db.KeyTypeMiscData:
+			fmt.Printf("[miscdata] K:%q V:%q\n", key[1:], it.Value())
+
+		case db.KeyTypeSequence:
+			folder := binary.BigEndian.Uint32(key[1:])
+			seq := binary.BigEndian.Uint64(key[5:])
+			fmt.Printf("[sequence] F:%d S:%d V:%q\n", folder, seq, it.Value())
+
+		case db.KeyTypeNeed:
+			folder := binary.BigEndian.Uint32(key[1:])
+			file := string(key[5:])
+			fmt.Printf("[need] F:%d V:%q\n", folder, file)
+
+		case db.KeyTypeBlockList:
+			fmt.Printf("[blocklist] H:%x\n", key[1:])
+
+		case db.KeyTypeBlockListMap:
+			folder := binary.BigEndian.Uint32(key[1:])
+			hash := key[5:37]
+			fileName := string(key[37:])
+			fmt.Printf("[blocklistmap] F:%d H:%x N:%s\n", folder, hash, fileName)
+
+		case db.KeyTypeVersion:
+			fmt.Printf("[version] H:%x", key[1:])
+			var v protocol.Vector
+			err := v.Unmarshal(it.Value())
+			if err != nil {
+				fmt.Printf(" (invalid)\n")
+			} else {
+				fmt.Printf(" V:%v\n", v)
+			}
+
+		case db.KeyTypePendingFolder:
+			device := binary.BigEndian.Uint32(key[1:])
+			folder := string(key[5:])
+			var of db.ObservedFolder
+			of.Unmarshal(it.Value())
+			fmt.Printf("[pendingFolder] D:%d F:%s V:%v\n", device, folder, of)
+
+		case db.KeyTypePendingDevice:
+			device := "<invalid>"
+			dev, err := protocol.DeviceIDFromBytes(key[1:])
+			if err == nil {
+				device = dev.String()
+			}
+			var od db.ObservedDevice
+			od.Unmarshal(it.Value())
+			fmt.Printf("[pendingDevice] D:%v V:%v\n", device, od)
+
+		default:
+			fmt.Printf("[??? %d]\n  %x\n  %x\n", key[0], key, it.Value())
+		}
+	}
+	return nil
+}

cmd/syncthing/cli/index_dumpsize.go

@@ -0,0 +1,106 @@
+// Copyright (C) 2015 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package cli
+
+import (
+	"container/heap"
+	"encoding/binary"
+	"fmt"
+
+	"github.com/urfave/cli"
+
+	"github.com/syncthing/syncthing/lib/db"
+)
+
+type SizedElement struct {
+	key  string
+	size int
+}
+
+type ElementHeap []SizedElement
+
+func (h ElementHeap) Len() int           { return len(h) }
+func (h ElementHeap) Less(i, j int) bool { return h[i].size > h[j].size }
+func (h ElementHeap) Swap(i, j int)      { h[i], h[j] = h[j], h[i] }
+
+func (h *ElementHeap) Push(x interface{}) {
+	*h = append(*h, x.(SizedElement))
+}
+
+func (h *ElementHeap) Pop() interface{} {
+	old := *h
+	n := len(old)
+	x := old[n-1]
+	*h = old[0 : n-1]
+	return x
+}
+
+func indexDumpSize(*cli.Context) error {
+	ldb, err := getDB()
+	if err != nil {
+		return err
+	}
+
+	h := &ElementHeap{}
+	heap.Init(h)
+
+	it, err := ldb.NewPrefixIterator(nil)
+	if err != nil {
+		return err
+	}
+	var ele SizedElement
+	for it.Next() {
+		key := it.Key()
+		switch key[0] {
+		case db.KeyTypeDevice:
+			folder := binary.BigEndian.Uint32(key[1:])
+			device := binary.BigEndian.Uint32(key[1+4:])
+			name := nulString(key[1+4+4:])
+			ele.key = fmt.Sprintf("DEVICE:%d:%d:%s", folder, device, name)
+
+		case db.KeyTypeGlobal:
+			folder := binary.BigEndian.Uint32(key[1:])
+			name := nulString(key[1+4:])
+			ele.key = fmt.Sprintf("GLOBAL:%d:%s", folder, name)
+
+		case db.KeyTypeBlock:
+			folder := binary.BigEndian.Uint32(key[1:])
+			hash := key[1+4 : 1+4+32]
+			name := nulString(key[1+4+32:])
+			ele.key = fmt.Sprintf("BLOCK:%d:%x:%s", folder, hash, name)
+
+		case db.KeyTypeDeviceStatistic:
+			ele.key = fmt.Sprintf("DEVICESTATS:%s", key[1:])
+
+		case db.KeyTypeFolderStatistic:
+			ele.key = fmt.Sprintf("FOLDERSTATS:%s", key[1:])
+
+		case db.KeyTypeVirtualMtime:
+			ele.key = fmt.Sprintf("MTIME:%s", key[1:])
+
+		case db.KeyTypeFolderIdx:
+			id := binary.BigEndian.Uint32(key[1:])
+			ele.key = fmt.Sprintf("FOLDERIDX:%d", id)
+
+		case db.KeyTypeDeviceIdx:
+			id := binary.BigEndian.Uint32(key[1:])
+			ele.key = fmt.Sprintf("DEVICEIDX:%d", id)
+
+		default:
+			ele.key = fmt.Sprintf("UNKNOWN:%x", key)
+		}
+		ele.size = len(it.Value())
+		heap.Push(h, ele)
+	}
+
+	for h.Len() > 0 {
+		ele = heap.Pop(h).(SizedElement)
+		fmt.Println(ele.key, ele.size)
+	}
+
+	return nil
+}

cmd/syncthing/cli/index_idxck.go

@@ -0,0 +1,357 @@
+// Copyright (C) 2018 The Syncthing Authors.
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this file,
+// You can obtain one at https://mozilla.org/MPL/2.0/.
+
+package cli
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"sort"
+
+	"github.com/urfave/cli"
+
+	"github.com/syncthing/syncthing/lib/db"
+	"github.com/syncthing/syncthing/lib/protocol"
+)
+
+type fileInfoKey struct {
+	folder uint32
+	device uint32
+	name   string
+}
+
+type globalKey struct {
+	folder uint32
+	name   string
+}
+
+type sequenceKey struct {
+	folder   uint32
+	sequence uint64
+}
+
+func indexCheck(*cli.Context) (err error) {
+	ldb, err := getDB()
+	if err != nil {
+		return err
+	}
+
+	folders := make(map[uint32]string)
+	devices := make(map[uint32]string)
+	deviceToIDs := make(map[string]uint32)
+	fileInfos := make(map[fileInfoKey]protocol.FileInfo)
+	globals := make(map[globalKey]db.VersionList)
+	sequences := make(map[sequenceKey]string)
+	needs := make(map[globalKey]struct{})
+	blocklists := make(map[string]struct{})
+	versions := make(map[string]protocol.Vector)
+	usedBlocklists := make(map[string]struct{})
+	usedVersions := make(map[string]struct{})
+	var localDeviceKey uint32
+	success := true
+	defer func() {
+		if err == nil {
+			if success {
+				fmt.Println("Index check completed succesfully.")
+			} else {
+				err = errors.New("Inconsistencies found in the index")
+			}
+		}
+	}()
+
+	it, err := ldb.NewPrefixIterator(nil)
+	if err != nil {
+		return err
+	}
+	for it.Next() {
+		key := it.Key()
+		switch key[0] {
+		case db.KeyTypeDevice:
+			folder := binary.BigEndian.Uint32(key[1:])
+			device := binary.BigEndian.Uint32(key[1+4:])
+			name := nulString(key[1+4+4:])
+
+			var f protocol.FileInfo
+			err := f.Unmarshal(it.Value())
+			if err != nil {
+				fmt.Println("Unable to unmarshal FileInfo:", err)
+				success = false
+				continue
+			}
+
+			fileInfos[fileInfoKey{folder, device, name}] = f
+
+		case db.KeyTypeGlobal:
+			folder := binary.BigEndian.Uint32(key[1:])
+			name := nulString(key[1+4:])
+			var flv db.VersionList
+			if err := flv.Unmarshal(it.Value()); err != nil {
+				fmt.Println("Unable to unmarshal VersionList:", err)
+				success = false
+				continue
+			}
+			globals[globalKey{folder, name}] = flv
+
+		case db.KeyTypeFolderIdx:
+			key := binary.BigEndian.Uint32(it.Key()[1:])
+			folders[key] = string(it.Value())
+
+		case db.KeyTypeDeviceIdx:
+			key := binary.BigEndian.Uint32(it.Key()[1:])
+			devices[key] = string(it.Value())
+			deviceToIDs[string(it.Value())] = key
+			if bytes.Equal(it.Value(), protocol.LocalDeviceID[:]) {
+				localDeviceKey = key
+			}
+
+		case db.KeyTypeSequence:
+			folder := binary.BigEndian.Uint32(key[1:])
+			seq := binary.BigEndian.Uint64(key[5:])
+			val := it.Value()
+			sequences[sequenceKey{folder, seq}] = string(val[9:])
+
+		case db.KeyTypeNeed:
+			folder := binary.BigEndian.Uint32(key[1:])
+			name := nulString(key[1+4:])
+			needs[globalKey{folder, name}] = struct{}{}
+
+		case db.KeyTypeBlockList:
+			hash := string(key[1:])
+			blocklists[hash] = struct{}{}
+
+		case db.KeyTypeVersion:
+			hash := string(key[1:])
+			var v protocol.Vector
+			if err := v.Unmarshal(it.Value()); err != nil {
+				fmt.Println("Unable to unmarshal Vector:", err)
+				success = false
+				continue
+			}
+			versions[hash] = v
+		}
+	}
+
+	if localDeviceKey == 0 {
+		fmt.Println("Missing key for local device in device index (bailing out)")
+		success = false
+		return
+	}
+
+	var missingSeq []sequenceKey
+	for fk, fi := range fileInfos {
+		if fk.name != fi.Name {
+			fmt.Printf("Mismatching FileInfo name, %q (key) != %q (actual)\n", fk.name, fi.Name)
+			success = false
+		}
+
+		folder := folders[fk.folder]
+		if folder == "" {
+			fmt.Printf("Unknown folder ID %d for FileInfo %q\n", fk.folder, fk.name)
+			success = false
+			continue
+		}
+		if devices[fk.device] == "" {
+			fmt.Printf("Unknown device ID %d for FileInfo %q, folder %q\n", fk.folder, fk.name, folder)
+			success = false
+		}
+
+		if fk.device == localDeviceKey {
+			sk := sequenceKey{fk.folder, uint64(fi.Sequence)}
+			name, ok := sequences[sk]
+			if !ok {
+				fmt.Printf("Sequence entry missing for FileInfo %q, folder %q, seq %d\n", fi.Name, folder, fi.Sequence)
+				missingSeq = append(missingSeq, sk)
+				success = false
+				continue
+			}
+			if name != fi.Name {
+				fmt.Printf("Sequence entry refers to wrong name, %q (seq) != %q (FileInfo), folder %q, seq %d\n", name, fi.Name, folder, fi.Sequence)
+				success = false
+			}
+		}
+
+		if len(fi.Blocks) == 0 && len(fi.BlocksHash) != 0 {
+			key := string(fi.BlocksHash)
+			if _, ok := blocklists[key]; !ok {
+				fmt.Printf("Missing block list for file %q, block list hash %x\n", fi.Name, fi.BlocksHash)
+				success = false
+			} else {
+				usedBlocklists[key] = struct{}{}
+			}
+		}
+
+		if fi.VersionHash != nil {
+			key := string(fi.VersionHash)
+			if _, ok := versions[key]; !ok {
+				fmt.Printf("Missing version vector for file %q, version hash %x\n", fi.Name, fi.VersionHash)
+				success = false
+			} else {
+				usedVersions[key] = struct{}{}
+			}
+		}
+
+		_, ok := globals[globalKey{fk.folder, fk.name}]
+		if !ok {
+			fmt.Printf("Missing global for file %q\n", fi.Name)
+			success = false
+			continue
+		}
+	}
+
+	// Aggregate the ranges of missing sequence entries, print them
+
+	sort.Slice(missingSeq, func(a, b int) bool {
+		if missingSeq[a].folder != missingSeq[b].folder {
+			return missingSeq[a].folder < missingSeq[b].folder
+		}
+		return missingSeq[a].sequence < missingSeq[b].sequence
+	})
+
+	var folder uint32
+	var startSeq, prevSeq uint64
+	for _, sk := range missingSeq {
+		if folder != sk.folder || sk.sequence != prevSeq+1 {
+			if folder != 0 {
+				fmt.Printf("Folder %d missing %d sequence entries: #%d - #%d\n", folder, prevSeq-startSeq+1, startSeq, prevSeq)
+			}
+			startSeq = sk.sequence
+			folder = sk.folder
+		}
+		prevSeq = sk.sequence
+	}
+	if folder != 0 {
+		fmt.Printf("Folder %d missing %d sequence entries: #%d - #%d\n", folder, prevSeq-startSeq+1, startSeq, prevSeq)
+	}
+
+	for gk, vl := range globals {
+		folder := folders[gk.folder]
+		if folder == "" {
+			fmt.Printf("Unknown folder ID %d for VersionList %q\n", gk.folder, gk.name)
+			success = false
+		}
+		checkGlobal := func(i int, device []byte, version protocol.Vector, invalid, deleted bool) {
+			dev, ok := deviceToIDs[string(device)]
+			if !ok {
+				fmt.Printf("VersionList %q, folder %q refers to unknown device %q\n", gk.name, folder, device)
+				success = false
+			}
+			fi, ok := fileInfos[fileInfoKey{gk.folder, dev, gk.name}]
+			if !ok {
+				fmt.Printf("VersionList %q, folder %q, entry %d refers to unknown FileInfo\n", gk.name, folder, i)
+				success = false
+			}
+
+			fiv := fi.Version
+			if fi.VersionHash != nil {
+				fiv = versions[string(fi.VersionHash)]
+			}
+			if !fiv.Equal(version) {
+				fmt.Printf("VersionList %q, folder %q, entry %d, FileInfo version mismatch, %v (VersionList) != %v (FileInfo)\n", gk.name, folder, i, version, fi.Version)
+				success = false
+			}
+			if fi.IsInvalid() != invalid {
+				fmt.Printf("VersionList %q, folder %q, entry %d, FileInfo invalid mismatch, %v (VersionList) != %v (FileInfo)\n", gk.name, folder, i, invalid, fi.IsInvalid())
+				success = false
+			}
+			if fi.IsDeleted() != deleted {
+				fmt.Printf("VersionList %q, folder %q, entry %d, FileInfo deleted mismatch, %v (VersionList) != %v (FileInfo)\n", gk.name, folder, i, deleted, fi.IsDeleted())
+				success = false
+			}
+		}
+		for i, fv := range vl.RawVersions {
+			for _, device := range fv.Devices {
+				checkGlobal(i, device, fv.Version, false, fv.Deleted)
+			}
+			for _, device := range fv.InvalidDevices {
+				checkGlobal(i, device, fv.Version, true, fv.Deleted)
+			}
+		}
+
+		// If we need this file we should have a need entry for it. False
+		// positives from needsLocally for deleted files, where we might
+		// legitimately lack an entry if we never had it, and ignored files.
+		if needsLocally(vl) {
+			_, ok := needs[gk]
+			if !ok {
+				fv, _ := vl.GetGlobal()
+				devB, _ := fv.FirstDevice()
+				dev := deviceToIDs[string(devB)]
+				fi := fileInfos[fileInfoKey{gk.folder, dev, gk.name}]
+				if !fi.IsDeleted() && !fi.IsIgnored() {
+					fmt.Printf("Missing need entry for needed file %q, folder %q\n", gk.name, folder)
+				}
+			}
+		}
+	}
+
+	seenSeq := make(map[fileInfoKey]uint64)
+	for sk, name := range sequences {
+		folder := folders[sk.folder]
+		if folder == "" {
+			fmt.Printf("Unknown folder ID %d for sequence entry %d, %q\n", sk.folder, sk.sequence, name)
+			success = false
+			continue
+		}
+
+		if prev, ok := seenSeq[fileInfoKey{folder: sk.folder, name: name}]; ok {
+			fmt.Printf("Duplicate sequence entry for %q, folder %q, seq %d (prev %d)\n", name, folder, sk.sequence, prev)
+			success = false
+		}
+		seenSeq[fileInfoKey{folder: sk.folder, name: name}] = sk.sequence
+
+		fi, ok := fileInfos[fileInfoKey{sk.folder, localDeviceKey, name}]
+		if !ok {
+			fmt.Printf("Missing FileInfo for sequence entry %d, folder %q, %q\n", sk.sequence, folder, name)
+			success = false
+			continue
+		}
+		if fi.Sequence != int64(sk.sequence) {
+			fmt.Printf("Sequence mismatch for %q, folder %q, %d (key) != %d (FileInfo)\n", name, folder, sk.sequence, fi.Sequence)
+			success = false
+		}
+	}
+
+	for nk := range needs {
+		folder := folders[nk.folder]
+		if folder == "" {
+			fmt.Printf("Unknown folder ID %d for need entry %q\n", nk.folder, nk.name)
+			success = false
+			continue
+		}
+
+		vl, ok := globals[nk]
+		if !ok {
+			fmt.Printf("Missing global for need entry %q, folder %q\n", nk.name, folder)
+			success = false
+			continue
+		}
+
+		if !needsLocally(vl) {
+			fmt.Printf("Need entry for file we don't need, %q, folder %q\n", nk.name, folder)
+			success = false
+		}
+	}
+
+	if d := len(blocklists) - len(usedBlocklists); d > 0 {
+		fmt.Printf("%d block list entries out of %d needs GC\n", d, len(blocklists))
+	}
+	if d := len(versions) - len(usedVersions); d > 0 {
+		fmt.Printf("%d version entries out of %d needs GC\n", d, len(versions))
+	}
+
+	return nil
+}
+
+func needsLocally(vl db.VersionList) bool {
+	gfv, gok := vl.GetGlobal()
+	if !gok { // That's weird, but we hardly need something non-existant
+		return false
+	}
+	fv, ok := vl.Get(protocol.LocalDeviceID[:])
+	return db.Need(gfv, ok, fv.Version)
+}

cmd/syncthing/cli/main.go

@@ -20,18 +20,21 @@ import (
 	"github.com/flynn-archive/go-shlex"
 	"github.com/mattn/go-isatty"
 	"github.com/pkg/errors"
+	"github.com/urfave/cli"
+
+	"github.com/syncthing/syncthing/cmd/syncthing/cmdutil"
 	"github.com/syncthing/syncthing/lib/config"
 	"github.com/syncthing/syncthing/lib/events"
 	"github.com/syncthing/syncthing/lib/locations"
 	"github.com/syncthing/syncthing/lib/protocol"
-	"github.com/urfave/cli"
 )
 
 type preCli struct {
 	GUIAddress string `name:"gui-address"`
 	GUIAPIKey  string `name:"gui-apikey"`
 	HomeDir    string `name:"home"`
-	ConfDir    string `name:"conf"`
+	ConfDir    string `name:"config"`
+	DataDir    string `name:"data"`
 }
 
 func Run() error {
@@ -44,17 +47,7 @@ func Run() error {
 	parseFlags(&c)
 
 	// Not set as default above because the strings can be really long.
-	var err error
-	homeSet := c.HomeDir != ""
-	confSet := c.ConfDir != ""
-	switch {
-	case homeSet && confSet:
-		err = errors.New("-home must not be used together with -conf")
-	case homeSet:
-		err = locations.SetBaseDir(locations.ConfigBaseDir, c.HomeDir)
-	case confSet:
-		err = locations.SetBaseDir(locations.ConfigBaseDir, c.ConfDir)
-	}
+	err := cmdutil.SetConfigDataLocationsFromFlags(c.HomeDir, c.ConfDir, c.DataDir)
 	if err != nil {
 		return errors.Wrap(err, "Command line options:")
 	}
@@ -98,20 +91,28 @@ func Run() error {
 
 	client := getClient(guiCfg)
 
-	cfg, err := getConfig(client)
+	cfg, cfgErr := getConfig(client)
 	original := cfg.Copy()
-	if err != nil {
-		return errors.Wrap(err, "getting config")
-	}
 
 	// Copy the config and set the default flags
 	recliCfg := recli.DefaultConfig
 	recliCfg.IDTag.Name = "xml"
 	recliCfg.SkipTag.Name = "json"
 
-	commands, err := recli.New(recliCfg).Construct(&cfg)
-	if err != nil {
-		return errors.Wrap(err, "config reflect")
+	configCommand := cli.Command{
+		Name:     "config",
+		HideHelp: true,
+		Usage:    "Configuration modification command group",
+	}
+	if cfgErr != nil {
+		configCommand.Action = func(*cli.Context) error {
+			return cfgErr
+		}
+	} else {
+		configCommand.Subcommands, err = recli.New(recliCfg).Construct(&cfg)
+		if err != nil {
+			return errors.Wrap(err, "config reflect")
+		}
 	}
 
 	// Implement the same flags at the upper CLI, but do nothing with them.
@@ -150,15 +151,11 @@ func Run() error {
 		Usage: "Syncthing command line interface",
 		Flags: fakeFlags,
 		Subcommands: []cli.Command{
-			{
-				Name:        "config",
-				HideHelp:    true,
-				Usage:       "Configuration modification command group",
-				Subcommands: commands,
-			},
+			configCommand,
 			showCommand,
 			operationCommand,
 			errorsCommand,
+			debugCommand,
 		},
 	}}
 
@@ -190,7 +187,7 @@ func Run() error {
 		}
 	}
 
-	if !reflect.DeepEqual(cfg, original) {
+	if cfgErr == nil && !reflect.DeepEqual(cfg, original) {
 		body, err := json.MarshalIndent(cfg, "", "  ")
 		if err != nil {
 			return err

cmd/syncthing/cli/show.go

@@ -18,27 +18,27 @@ var showCommand = cli.Command{
 		{
 			Name:   "version",
 			Usage:  "Show syncthing client version",
-			Action: expects(0, dumpOutput("system/version")),
+			Action: expects(0, indexDumpOutput("system/version")),
 		},
 		{
 			Name:   "config-status",
 			Usage:  "Show configuration status, whether or not a restart is required for changes to take effect",
-			Action: expects(0, dumpOutput("config/restart-required")),
+			Action: expects(0, indexDumpOutput("config/restart-required")),
 		},
 		{
 			Name:   "system",
 			Usage:  "Show system status",
-			Action: expects(0, dumpOutput("system/status")),
+			Action: expects(0, indexDumpOutput("system/status")),
 		},
 		{
 			Name:   "connections",
 			Usage:  "Report about connections to other devices",
-			Action: expects(0, dumpOutput("system/connections")),
+			Action: expects(0, indexDumpOutput("system/connections")),
 		},
 		{
 			Name:   "usage",
 			Usage:  "Show usage report",
-			Action: expects(0, dumpOutput("svc/report")),
+			Action: expects(0, indexDumpOutput("svc/report")),
 		},
 	},
 }

cmd/syncthing/cli/utils.go

@@ -8,12 +8,17 @@ package cli
 
 import (
 	"encoding/json"
+	"errors"
 	"fmt"
 	"io/ioutil"
+	"mime"
 	"net/http"
 	"os"
+	"path/filepath"
 
 	"github.com/syncthing/syncthing/lib/config"
+	"github.com/syncthing/syncthing/lib/db/backend"
+	"github.com/syncthing/syncthing/lib/locations"
 	"github.com/urfave/cli"
 )
 
@@ -33,7 +38,7 @@ func emptyPost(url string) cli.ActionFunc {
 	}
 }
 
-func dumpOutput(url string) cli.ActionFunc {
+func indexDumpOutput(url string) cli.ActionFunc {
 	return func(c *cli.Context) error {
 		client := c.App.Metadata["client"].(*APIClient)
 		response, err := client.Get(url)
@@ -44,6 +49,39 @@ func dumpOutput(url string) cli.ActionFunc {
 	}
 }
 
+func saveToFile(url string) cli.ActionFunc {
+	return func(c *cli.Context) error {
+		client := c.App.Metadata["client"].(*APIClient)
+		response, err := client.Get(url)
+		if err != nil {
+			return err
+		}
+		_, params, err := mime.ParseMediaType(response.Header.Get("Content-Disposition"))
+		if err != nil {
+			return err
+		}
+		filename := params["filename"]
+		if filename == "" {
+			return errors.New("Missing filename in response")
+		}
+		bs, err := responseToBArray(response)
+		if err != nil {
+			return err
+		}
+		f, err := os.Create(filename)
+		if err != nil {
+			return err
+		}
+		defer f.Close()
+		_, err = f.Write(bs)
+		if err != nil {
+			return err
+		}
+		fmt.Println("Wrote results to", filename)
+		return err
+	}
+}
+
 func getConfig(c *APIClient) (config.Configuration, error) {
 	cfg := config.Configuration{}
 	response, err := c.Get("system/config")
@@ -92,3 +130,20 @@ func prettyPrintResponse(c *cli.Context, response *http.Response) error {
 	// TODO: Check flag for pretty print format
 	return prettyPrintJSON(data)
 }
+
+func getDB() (backend.Backend, error) {
+	return backend.OpenLevelDBRO(locations.Get(locations.Database))
+}
+
+func nulString(bs []byte) string {
+	for i := range bs {
+		if bs[i] == 0 {
+			return string(bs[:i])
+		}
+	}
+	return string(bs)
+}
+
+func normalizePath(path string) string {
+	return filepath.ToSlash(filepath.Clean(path))
+}