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syscallcompat: Drop Fstatat emulation on macOS.

This commit is contained in:
Sebastian Lackner 2019-01-14 03:00:49 +01:00 committed by rfjakob
parent 4134ff7570
commit a9d8eb49ef
6 changed files with 45 additions and 71 deletions
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22
internal/syscallcompat/emulate.go
View File

@ -4,8 +4,6 @@ import (
"path/filepath"
"sync"
"syscall"
"golang.org/x/sys/unix"
)
var chdirMutex sync.Mutex
@ -29,23 +27,3 @@ func emulateMknodat(dirfd int, path string, mode uint32, dev int) error {
}
return syscall.Mknod(path, mode, dev)
}
// emulateFstatat emulates the syscall for platforms that don't have it
// in the kernel (darwin).
func emulateFstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
if !filepath.IsAbs(path) {
chdirMutex.Lock()
defer chdirMutex.Unlock()
cwd, err := syscall.Open(".", syscall.O_RDONLY, 0)
if err != nil {
return err
}
defer syscall.Close(cwd)
err = syscall.Fchdir(dirfd)
if err != nil {
return err
}
defer syscall.Fchdir(cwd)
}
return unix.Lstat(path, stat)
}

35
internal/syscallcompat/emulate_test.go
View File

@ -26,38 +26,3 @@ func TestEmulateMknodat(t *testing.T) {
t.Fatal(err)
}
}
func TestEmulateFstatat(t *testing.T) {
var st unix.Stat_t
// stat a normal file (size 3)
f, err := os.Create(tmpDir + "/fstatat")
if err != nil {
t.Fatal(err)
}
_, err = f.Write([]byte("foo"))
if err != nil {
t.Fatal(err)
}
f.Close()
err = emulateFstatat(tmpDirFd, "fstatat", &st, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
t.Fatal(err)
}
if st.Size != 3 {
t.Errorf("wrong file size: %d", st.Size)
}
// stat a symlink and check that the size matches the length of the
// symlink target. This proves that we have stat'ed the symlink itself.
err = os.Symlink(tmpDir+"/fstatat", tmpDir+"/fstatatSymlink")
if err != nil {
t.Fatal(err)
}
err = emulateFstatat(tmpDirFd, "fstatatSymlink", &st, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
t.Fatal(err)
}
expectedSize := int64(len(tmpDir + "/fstatat"))
if st.Size != expectedSize {
t.Errorf("symlink size: expected=%d, got=%d", expectedSize, st.Size)
}
}

10
internal/syscallcompat/sys_common.go
View File

@ -97,6 +97,16 @@ func Mkdirat(dirfd int, path string, mode uint32) (err error) {
return unix.Mkdirat(dirfd, path, mode)
}
// Fstatat syscall.
func Fstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
// Why would we ever want to call this without AT_SYMLINK_NOFOLLOW?
if flags&unix.AT_SYMLINK_NOFOLLOW == 0 {
tlog.Warn.Printf("Fstatat: adding missing AT_SYMLINK_NOFOLLOW flag")
flags |= unix.AT_SYMLINK_NOFOLLOW
}
return unix.Fstatat(dirfd, path, stat, flags)
}
const XATTR_SIZE_MAX = 65536
// Make the buffer 1kB bigger so we can detect overflows

35
internal/syscallcompat/sys_common_test.go
View File

@ -273,3 +273,38 @@ func TestMkdirat(t *testing.T) {
t.Fatalf("mkdirat did not create a directory")
}
}
func TestFstatat(t *testing.T) {
var st unix.Stat_t
// stat a normal file (size 3)
f, err := os.Create(tmpDir + "/fstatat")
if err != nil {
t.Fatal(err)
}
_, err = f.Write([]byte("foo"))
if err != nil {
t.Fatal(err)
}
f.Close()
err = Fstatat(tmpDirFd, "fstatat", &st, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
t.Fatal(err)
}
if st.Size != 3 {
t.Errorf("wrong file size: %d", st.Size)
}
// stat a symlink and check that the size matches the length of the
// symlink target. This proves that we have stat'ed the symlink itself.
err = os.Symlink(tmpDir+"/fstatat", tmpDir+"/fstatatSymlink")
if err != nil {
t.Fatal(err)
}
err = Fstatat(tmpDirFd, "fstatatSymlink", &st, unix.AT_SYMLINK_NOFOLLOW)
if err != nil {
t.Fatal(err)
}
expectedSize := int64(len(tmpDir + "/fstatat"))
if st.Size != expectedSize {
t.Errorf("symlink size: expected=%d, got=%d", expectedSize, st.Size)
}
}

4
internal/syscallcompat/sys_darwin.go
View File

@ -132,10 +132,6 @@ func MkdiratUser(dirfd int, path string, mode uint32, context *fuse.Context) (er
return Mkdirat(dirfd, path, mode)
}
func Fstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
return emulateFstatat(dirfd, path, stat, flags)
}
func Getdents(fd int) ([]fuse.DirEntry, error) {
return emulateGetdents(fd)
}

10
internal/syscallcompat/sys_linux.go
View File

@ -198,16 +198,6 @@ func MkdiratUser(dirfd int, path string, mode uint32, context *fuse.Context) (er
return Mkdirat(dirfd, path, mode)
}
// Fstatat syscall.
func Fstatat(dirfd int, path string, stat *unix.Stat_t, flags int) (err error) {
// Why would we ever want to call this without AT_SYMLINK_NOFOLLOW?
if flags&unix.AT_SYMLINK_NOFOLLOW == 0 {
tlog.Warn.Printf("Fstatat: adding missing AT_SYMLINK_NOFOLLOW flag")
flags |= unix.AT_SYMLINK_NOFOLLOW
}
return unix.Fstatat(dirfd, path, stat, flags)
}
// Getdents syscall.
func Getdents(fd int) ([]fuse.DirEntry, error) {
return getdents(fd)