hardcoresushi/libgocryptfs
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syscallcompat: switch from syscall.Getdents to unix.Getdents

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On mips64le, syscall.Getdents() and struct syscall.Dirent do
not fit together, causing our Getdents implementation to
return garbage ( https://github.com/rfjakob/gocryptfs/issues/200
and https://github.com/golang/go/issues/23624 ).

Switch to unix.Getdents which does not have this problem -
the next Go release with the syscall package fixes is too
far away, and will take time to trickle into distros.
This commit is contained in:
Jakob Unterwurzacher 2018-01-31 18:59:10 +01:00
parent b611e01035
commit 26ba8103bf
1 changed files with 6 additions and 6 deletions
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12
internal/syscallcompat/getdents_linux.go
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@ -19,14 +19,14 @@ import (
"github.com/rfjakob/gocryptfs/internal/tlog" "github.com/rfjakob/gocryptfs/internal/tlog"
) )
const sizeofDirent = int(unsafe.Sizeof(syscall.Dirent{})) const sizeofDirent = int(unsafe.Sizeof(unix.Dirent{}))
// maxReclen sanity check: Reclen should never be larger than this. // maxReclen sanity check: Reclen should never be larger than this.
// Due to padding between entries, it is 280 even on 32-bit architectures. // Due to padding between entries, it is 280 even on 32-bit architectures.
// See https://github.com/rfjakob/gocryptfs/issues/197 for details. // See https://github.com/rfjakob/gocryptfs/issues/197 for details.
const maxReclen = 280 const maxReclen = 280
// getdents wraps syscall.Getdents and converts the result to []fuse.DirEntry. // getdents wraps unix.Getdents and converts the result to []fuse.DirEntry.
func getdents(fd int) ([]fuse.DirEntry, error) { func getdents(fd int) ([]fuse.DirEntry, error) {
// Collect syscall result in smartBuf. // Collect syscall result in smartBuf.
// "bytes.Buffer" is smart about expanding the capacity and avoids the // "bytes.Buffer" is smart about expanding the capacity and avoids the
@ -34,7 +34,7 @@ func getdents(fd int) ([]fuse.DirEntry, error) {
var smartBuf bytes.Buffer var smartBuf bytes.Buffer
tmp := make([]byte, 10000) tmp := make([]byte, 10000)
for { for {
n, err := syscall.Getdents(fd, tmp) n, err := unix.Getdents(fd, tmp)
if err != nil { if err != nil {
return nil, err return nil, err
} }
@ -51,7 +51,7 @@ func getdents(fd int) ([]fuse.DirEntry, error) {
// a fuse.DirEntry slice of the correct size at once. // a fuse.DirEntry slice of the correct size at once.
var numEntries, offset int var numEntries, offset int
for offset < len(buf) { for offset < len(buf) {
s := *(*syscall.Dirent)(unsafe.Pointer(&buf[offset])) s := *(*unix.Dirent)(unsafe.Pointer(&buf[offset]))
if s.Reclen == 0 { if s.Reclen == 0 {
tlog.Warn.Printf("Getdents: corrupt entry #%d: Reclen=0 at offset=%d. Returning EBADR", tlog.Warn.Printf("Getdents: corrupt entry #%d: Reclen=0 at offset=%d. Returning EBADR",
numEntries, offset) numEntries, offset)
@ -73,7 +73,7 @@ func getdents(fd int) ([]fuse.DirEntry, error) {
entries := make([]fuse.DirEntry, 0, numEntries) entries := make([]fuse.DirEntry, 0, numEntries)
offset = 0 offset = 0
for offset < len(buf) { for offset < len(buf) {
s := *(*syscall.Dirent)(unsafe.Pointer(&buf[offset])) s := *(*unix.Dirent)(unsafe.Pointer(&buf[offset]))
name, err := getdentsName(s) name, err := getdentsName(s)
if err != nil { if err != nil {
return nil, err return nil, err
@ -100,7 +100,7 @@ func getdents(fd int) ([]fuse.DirEntry, error) {
// getdentsName extracts the filename from a Dirent struct and returns it as // getdentsName extracts the filename from a Dirent struct and returns it as
// a Go string. // a Go string.
func getdentsName(s syscall.Dirent) (string, error) { func getdentsName(s unix.Dirent) (string, error) {
// After the loop, l contains the index of the first '\0'. // After the loop, l contains the index of the first '\0'.
l := 0 l := 0
for l = range s.Name { for l = range s.Name {