fsck: report skipped corrupt files

OpenDir and ListXAttr skip over corrupt entries,
readFileID treats files the are too small as empty.
This improves usability in the face of corruption,
but hides the problem in a log message instead of
putting it in the return code.

Create a channel to report these corruptions to fsck
so it can report them to the user.

Also update the manpage and the changelog with the -fsck option.

Closes https://github.com/rfjakob/gocryptfs/issues/191

1 files changed, 47 insertions, 5 deletions

diff --git a/fsck.go b/fsck.go
index 9eff72e..d1dc7e5 100644
--- a/fsck.go
+++ b/fsck.go
@@ -6,6 +6,7 @@ import (
 	"path/filepath"
 	"sort"
 	"strings"
+	"sync"
 	"syscall"
 
 	"github.com/hanwen/go-fuse/fuse"
@@ -19,17 +20,34 @@ type fsckObj struct {
 	fs *fusefrontend.FS
 	// List of corrupt files
 	corruptList []string
+	// Protects corruptList
+	corruptListLock sync.Mutex
 }
 
 func (ck *fsckObj) markCorrupt(path string) {
+	ck.corruptListLock.Lock()
 	ck.corruptList = append(ck.corruptList, path)
+	ck.corruptListLock.Unlock()
 }
 
 // Recursively check dir for corruption
 func (ck *fsckObj) dir(path string) {
 	//fmt.Printf("ck.dir %q\n", path)
 	ck.xattrs(path)
+	done := make(chan struct{})
+	go func() {
+		for {
+			select {
+			case item := <-ck.fs.CorruptItems:
+				fmt.Printf("fsck: corrupt entry in dir %q: %q\n", path, item)
+				ck.markCorrupt(filepath.Join(path, item))
+			case <-done:
+				return
+			}
+		}
+	}()
 	entries, status := ck.fs.OpenDir(path, nil)
+	done <- struct{}{}
 	if !status.Ok() {
 		ck.markCorrupt(path)
 		fmt.Printf("fsck: error opening dir %q: %v\n", path, status)
@@ -80,6 +98,19 @@ func (ck *fsckObj) file(path string) {
 	defer f.Release()
 	buf := make([]byte, fuse.MAX_KERNEL_WRITE)
 	var off int64
+	done := make(chan struct{})
+	go func() {
+		for {
+			select {
+			case item := <-ck.fs.CorruptItems:
+				fmt.Printf("fsck: corrupt file %q (inode %s)\n", path, item)
+				ck.markCorrupt(path)
+			case <-done:
+				return
+			}
+		}
+	}()
+	defer func() { done <- struct{}{} }()
 	for {
 		result, status := f.Read(buf, off)
 		if !status.Ok() {
@@ -97,7 +128,20 @@ func (ck *fsckObj) file(path string) {
 
 // Check xattrs on file/dir at path
 func (ck *fsckObj) xattrs(path string) {
+	done := make(chan struct{})
+	go func() {
+		for {
+			select {
+			case item := <-ck.fs.CorruptItems:
+				fmt.Printf("fsck: corrupt xattr name on file %q: %q\n", path, item)
+				ck.markCorrupt(path + " xattr:" + item)
+			case <-done:
+				return
+			}
+		}
+	}()
 	attrs, status := ck.fs.ListXAttr(path, nil)
+	done <- struct{}{}
 	if !status.Ok() {
 		fmt.Printf("fsck: error listing xattrs on %q: %v\n", path, status)
 		ck.markCorrupt(path)
@@ -120,19 +164,17 @@ func fsck(args *argContainer) {
 	args.allow_other = false
 	pfs, wipeKeys := initFuseFrontend(args)
 	fs := pfs.(*fusefrontend.FS)
+	fs.CorruptItems = make(chan string)
 	ck := fsckObj{
 		fs: fs,
 	}
 	ck.dir("")
 	wipeKeys()
 	if len(ck.corruptList) == 0 {
-		fmt.Printf("fsck summary: no problems found")
+		fmt.Printf("fsck summary: no problems found\n")
 		return
 	}
-	fmt.Printf("fsck summary: found %d corrupt files:\n", len(ck.corruptList))
-	for _, path := range ck.corruptList {
-		fmt.Printf("  %q\n", path)
-	}
+	fmt.Printf("fsck summary: %d corrupt files\n", len(ck.corruptList))
 	os.Exit(exitcodes.FsckErrors)
 }