Commit a856a74e authored by Han-Wen Nienhuys's avatar Han-Wen Nienhuys

nodefs: protect against double close

Access file descriptors under lock, and set to -1 on close. This
avoids confusing errors if Close() is doubly called
parent 4f40cf4c
......@@ -5,6 +5,7 @@
package nodefs
import (
"sync"
"syscall"
"unsafe"
......@@ -14,6 +15,9 @@ import (
type loopbackDirStream struct {
buf []byte
todo []byte
// Protects fd so we can guard against double close
mu sync.Mutex
fd int
}
......@@ -37,14 +41,23 @@ func NewLoopbackDirStream(name string) (DirStream, syscall.Errno) {
}
func (ds *loopbackDirStream) Close() {
ds.mu.Lock()
defer ds.mu.Unlock()
if ds.fd != -1 {
syscall.Close(ds.fd)
ds.fd = -1
}
}
func (ds *loopbackDirStream) HasNext() bool {
ds.mu.Lock()
defer ds.mu.Unlock()
return len(ds.todo) > 0
}
func (ds *loopbackDirStream) Next() (fuse.DirEntry, syscall.Errno) {
ds.mu.Lock()
defer ds.mu.Unlock()
de := (*syscall.Dirent)(unsafe.Pointer(&ds.todo[0]))
nameBytes := ds.todo[unsafe.Offsetof(syscall.Dirent{}.Name):de.Reclen]
......
......@@ -6,6 +6,8 @@ package nodefs
import (
"context"
"sync"
// "time"
"syscall"
......@@ -21,6 +23,7 @@ func NewLoopbackFile(fd int) FileHandle {
}
type loopbackFile struct {
mu sync.Mutex
fd int
}
......@@ -39,21 +42,33 @@ var _ = (FileSetattrer)((*loopbackFile)(nil))
var _ = (FileAllocater)((*loopbackFile)(nil))
func (f *loopbackFile) Read(ctx context.Context, buf []byte, off int64) (res fuse.ReadResult, errno syscall.Errno) {
f.mu.Lock()
defer f.mu.Unlock()
r := fuse.ReadResultFd(uintptr(f.fd), off, len(buf))
return r, OK
}
func (f *loopbackFile) Write(ctx context.Context, data []byte, off int64) (uint32, syscall.Errno) {
f.mu.Lock()
defer f.mu.Unlock()
n, err := syscall.Pwrite(f.fd, data, off)
return uint32(n), ToErrno(err)
}
func (f *loopbackFile) Release(ctx context.Context) syscall.Errno {
f.mu.Lock()
defer f.mu.Unlock()
if f.fd != -1 {
err := syscall.Close(f.fd)
f.fd = -1
return ToErrno(err)
}
return syscall.EBADF
}
func (f *loopbackFile) Flush(ctx context.Context) syscall.Errno {
f.mu.Lock()
defer f.mu.Unlock()
// Since Flush() may be called for each dup'd fd, we don't
// want to really close the file, we just want to flush. This
// is achieved by closing a dup'd fd.
......@@ -67,6 +82,8 @@ func (f *loopbackFile) Flush(ctx context.Context) syscall.Errno {
}
func (f *loopbackFile) Fsync(ctx context.Context, flags uint32) (errno syscall.Errno) {
f.mu.Lock()
defer f.mu.Unlock()
r := ToErrno(syscall.Fsync(f.fd))
return r
......@@ -79,6 +96,8 @@ const (
)
func (f *loopbackFile) Getlk(ctx context.Context, owner uint64, lk *fuse.FileLock, flags uint32, out *fuse.FileLock) (errno syscall.Errno) {
f.mu.Lock()
defer f.mu.Unlock()
flk := syscall.Flock_t{}
lk.ToFlockT(&flk)
errno = ToErrno(syscall.FcntlFlock(uintptr(f.fd), _OFD_GETLK, &flk))
......@@ -95,6 +114,8 @@ func (f *loopbackFile) Setlkw(ctx context.Context, owner uint64, lk *fuse.FileLo
}
func (f *loopbackFile) setLock(ctx context.Context, owner uint64, lk *fuse.FileLock, flags uint32, blocking bool) (errno syscall.Errno) {
f.mu.Lock()
defer f.mu.Unlock()
if (flags & fuse.FUSE_LK_FLOCK) != 0 {
var op int
switch lk.Typ {
......@@ -133,6 +154,8 @@ func (f *loopbackFile) Setattr(ctx context.Context, in *fuse.SetAttrIn, out *fus
}
func (f *loopbackFile) setAttr(ctx context.Context, in *fuse.SetAttrIn) syscall.Errno {
f.mu.Lock()
defer f.mu.Unlock()
var errno syscall.Errno
if mode, ok := in.GetMode(); ok {
errno = ToErrno(syscall.Fchmod(f.fd, mode))
......@@ -187,6 +210,8 @@ func (f *loopbackFile) setAttr(ctx context.Context, in *fuse.SetAttrIn) syscall.
}
func (f *loopbackFile) Getattr(ctx context.Context, a *fuse.AttrOut) syscall.Errno {
f.mu.Lock()
defer f.mu.Unlock()
st := syscall.Stat_t{}
err := syscall.Fstat(f.fd, &st)
if err != nil {
......@@ -198,6 +223,8 @@ func (f *loopbackFile) Getattr(ctx context.Context, a *fuse.AttrOut) syscall.Err
}
func (f *loopbackFile) Lseek(ctx context.Context, off uint64, whence uint32) (uint64, syscall.Errno) {
f.mu.Lock()
defer f.mu.Unlock()
n, err := unix.Seek(f.fd, int64(off), int(whence))
return uint64(n), ToErrno(err)
}
......@@ -13,6 +13,8 @@ import (
)
func (f *loopbackFile) Allocate(ctx context.Context, off uint64, sz uint64, mode uint32) syscall.Errno {
f.mu.Lock()
defer f.mu.Unlock()
err := syscall.Fallocate(f.fd, mode, int64(off), int64(sz))
if err != nil {
return ToErrno(err)
......
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