fsck: add initial implementation

Most corruption cases except xattr should be covered.
With test filesystem.

The output is still pretty ugly. xattr support will
be added in the next commits.

1 files changed, 97 insertions, 2 deletions

diff --git a/fsck.go b/fsck.go
index 645cf91..7741d19 100644
--- a/fsck.go
+++ b/fsck.go
@@ -1,9 +1,104 @@
 package main
 
 import (
-	"log"
+	"fmt"
+	"os"
+	"path/filepath"
+	"syscall"
+
+	"github.com/hanwen/go-fuse/fuse"
+
+	"github.com/rfjakob/gocryptfs/internal/exitcodes"
+	"github.com/rfjakob/gocryptfs/internal/fusefrontend"
+	"github.com/rfjakob/gocryptfs/internal/tlog"
 )
 
+type fsckObj struct {
+	fs         *fusefrontend.FS
+	errorCount int
+}
+
+// Recursively check dir for corruption
+func (ck *fsckObj) dir(path string) {
+	//fmt.Printf("ck.dir %q\n", path)
+	entries, status := ck.fs.OpenDir(path, nil)
+	if !status.Ok() {
+		fmt.Printf("fsck: error opening dir %q: %v\n", path, status)
+		ck.errorCount++
+		return
+	}
+	for _, entry := range entries {
+		if entry.Name == "." || entry.Name == ".." {
+			continue
+		}
+		nextPath := filepath.Join(path, entry.Name)
+		filetype := entry.Mode & syscall.S_IFMT
+		//fmt.Printf("  %q %x\n", entry.Name, entry.Mode)
+		switch filetype {
+		case syscall.S_IFDIR:
+			ck.dir(nextPath)
+		case syscall.S_IFREG:
+			ck.file(nextPath)
+		case syscall.S_IFLNK:
+			ck.symlink(nextPath)
+		case syscall.S_IFIFO, syscall.S_IFSOCK, syscall.S_IFBLK, syscall.S_IFCHR:
+			// nothing to check
+		default:
+			fmt.Printf("fsck: unhandle file type %x\n", filetype)
+		}
+	}
+}
+
+func (ck *fsckObj) symlink(path string) {
+	_, status := ck.fs.Readlink(path, nil)
+	if !status.Ok() {
+		fmt.Printf("fsck: error reading symlink %q: %v\n", path, status)
+		ck.errorCount++
+	}
+}
+
+// check file for corruption
+func (ck *fsckObj) file(path string) {
+	//fmt.Printf("ck.file %q\n", path)
+	f, status := ck.fs.Open(path, syscall.O_RDONLY, nil)
+	if !status.Ok() {
+		fmt.Printf("fsck: error opening file %q: %v\n", path, status)
+		ck.errorCount++
+		return
+	}
+	defer f.Release()
+	buf := make([]byte, fuse.MAX_KERNEL_WRITE)
+	var off int64
+	for {
+		result, status := f.Read(buf, off)
+		if !status.Ok() {
+			fmt.Printf("fsck: error reading file %q at offset %d: %v\n", path, off, status)
+			ck.errorCount++
+			return
+		}
+		// EOF
+		if result.Size() == 0 {
+			return
+		}
+		off += int64(result.Size())
+	}
+}
+
 func fsck(args *argContainer) {
-	log.Panic("Not yet implemented")
+	if args.reverse {
+		tlog.Fatal.Printf("Running -fsck with -reverse is not supported")
+		os.Exit(exitcodes.Usage)
+	}
+	args.allow_other = false
+	pfs, wipeKeys := initFuseFrontend(args)
+	defer wipeKeys()
+	fs := pfs.(*fusefrontend.FS)
+	ck := fsckObj{
+		fs: fs,
+	}
+	ck.dir("")
+	fmt.Printf("fsck: found %d problems\n", ck.errorCount)
+	if ck.errorCount != 0 {
+		os.Exit(exitcodes.FsckErrors)
+	}
 }