diff options
| -rwxr-xr-x | build.bash | 5 | ||||
| -rw-r--r-- | contrib/findholes/.gitignore | 1 | ||||
| -rw-r--r-- | contrib/findholes/holes/holes.go | 106 | ||||
| -rw-r--r-- | contrib/findholes/main.go | 34 |
4 files changed, 144 insertions, 2 deletions
@@ -94,8 +94,9 @@ fi # Actual "go build" call for gocryptfs go build "-ldflags=$GO_LDFLAGS" "$@" # Additional binaries -(cd gocryptfs-xray; go build "-ldflags=$GO_LDFLAGS" "$@") -(cd contrib/statfs; go build "-ldflags=$GO_LDFLAGS" "$@") +for d in gocryptfs-xray contrib/statfs contrib/findholes ; do + (cd "$d"; go build "-ldflags=$GO_LDFLAGS" "$@") +done ./gocryptfs -version diff --git a/contrib/findholes/.gitignore b/contrib/findholes/.gitignore new file mode 100644 index 0000000..15c37f6 --- /dev/null +++ b/contrib/findholes/.gitignore @@ -0,0 +1 @@ +/findholes diff --git a/contrib/findholes/holes/holes.go b/contrib/findholes/holes/holes.go new file mode 100644 index 0000000..a2c16de --- /dev/null +++ b/contrib/findholes/holes/holes.go @@ -0,0 +1,106 @@ +// Package holes finds and pretty-prints holes & data sections of a file. +// Used by TestFileHoleCopy in the gocryptfs test suite. +package holes + +import ( + "fmt" + "syscall" +) + +const ( + SEEK_DATA = 3 + SEEK_HOLE = 4 + + SegmentHole = SegmentType(100) + SegmentData = SegmentType(101) + SegmentEOF = SegmentType(102) +) + +type Segment struct { + Offset int64 + Type SegmentType +} + +func (s Segment) String() string { + return fmt.Sprintf("%10d %v", s.Offset, s.Type) +} + +type SegmentType int + +func (s SegmentType) String() string { + switch s { + case SegmentHole: + return "hole" + case SegmentData: + return "data" + case SegmentEOF: + return "eof" + default: + return "???" + } +} + +// PrettyPrint pretty-prints the Segments. +func PrettyPrint(segments []Segment) (out string) { + for _, s := range segments { + out += "\n" + s.String() + } + return out +} + +// Find examines the file passed via file descriptor and returns the found holes +// and data sections. +func Find(fd int) (segments []Segment, err error) { + var st syscall.Stat_t + err = syscall.Fstat(fd, &st) + if err != nil { + return nil, err + } + totalSize := st.Size + + var cursor int64 + + // find out if file starts with data or hole + off, err := syscall.Seek(fd, 0, SEEK_DATA) + if err == syscall.ENXIO { + segments = append(segments, + Segment{0, SegmentHole}, + Segment{totalSize, SegmentEOF}) + return segments, nil + } + if err != nil { + return nil, err + } + if off == cursor { + segments = append(segments, Segment{0, SegmentData}) + } else { + segments = append(segments, + Segment{0, SegmentHole}, + Segment{totalSize, SegmentData}) + cursor = off + } + + // now we are at the start of data. + // find next hole, then next data, then next hole, then next data... + for { + cursor, err = syscall.Seek(fd, cursor, SEEK_HOLE) + if err != nil { + return nil, err + } + if cursor == totalSize { + segments = append(segments, Segment{cursor, SegmentEOF}) + break + } + segments = append(segments, Segment{cursor, SegmentHole}) + cursor, err = syscall.Seek(fd, cursor, SEEK_DATA) + if err != nil { + return nil, err + } + if cursor == totalSize { + segments = append(segments, Segment{cursor, SegmentEOF}) + break + } + segments = append(segments, Segment{cursor, SegmentData}) + } + return segments, nil +} diff --git a/contrib/findholes/main.go b/contrib/findholes/main.go new file mode 100644 index 0000000..6f1ae64 --- /dev/null +++ b/contrib/findholes/main.go @@ -0,0 +1,34 @@ +// Find and pretty-print holes & data sections of a file. +package main + +import ( + "flag" + "fmt" + "os" + + "github.com/rfjakob/gocryptfs/contrib/findholes/holes" +) + +func main() { + flag.Parse() + if flag.NArg() != 1 { + fmt.Printf("Usage: findholes FILE\n") + os.Exit(1) + } + + f, err := os.Open(flag.Arg(0)) + if err != nil { + // os.Open() gives nicer error messages than syscall.Open() + fmt.Println(err) + os.Exit(1) + } + defer f.Close() + + segments, err := holes.Find(int(f.Fd())) + if err != nil { + fmt.Println(err) + os.Exit(1) + } + + fmt.Println(holes.PrettyPrint(segments)) +} |