// Fill in the response that should be sent to the kernel, or set noResponse if
// the op requires no response.
func (c *Connection) kernelResponse(
m *buffer.OutMessage,
fuseID uint64,
op interface{},
opErr error) (noResponse bool) {
h := m.OutHeader()
h.Unique = fuseID
// Special case: handle the ops for which the kernel expects no response.
// interruptOp .
switch op.(type) {
case *fuseops.ForgetInodeOp:
noResponse = true
return
case *interruptOp:
noResponse = true
return
}
// If the user returned the error, fill in the error field of the outgoing
// message header.
if opErr != nil {
m.OutHeader().Error = -int32(syscall.EIO)
if errno, ok := opErr.(syscall.Errno); ok {
m.OutHeader().Error = -int32(errno)
}
// Special case: for some types, convertInMessage grew the message in order
// to obtain a destination buffer. Make sure that we shrink back to just
// the header, because on OS X the kernel otherwise returns EINVAL when we
// attempt to write an error response with a length that extends beyond the
// header.
m.ShrinkTo(buffer.OutMessageInitialSize)
}
// Otherwise, fill in the rest of the response.
if opErr == nil {
c.kernelResponseForOp(m, op)
}
h.Len = uint32(m.Len())
return
}
// Like kernelResponse, but assumes the user replied with a nil error to the
// op.
func (c *Connection) kernelResponseForOp(
m *buffer.OutMessage,
op interface{}) {
// Create the appropriate output message
switch o := op.(type) {
case *fuseops.LookUpInodeOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.GetInodeAttributesOp:
size := fusekernel.AttrOutSize(c.protocol)
out := (*fusekernel.AttrOut)(m.Grow(size))
out.AttrValid, out.AttrValidNsec = convertExpirationTime(
o.AttributesExpiration)
convertAttributes(o.Inode, &o.Attributes, &out.Attr)
case *fuseops.SetInodeAttributesOp:
size := fusekernel.AttrOutSize(c.protocol)
out := (*fusekernel.AttrOut)(m.Grow(size))
out.AttrValid, out.AttrValidNsec = convertExpirationTime(
o.AttributesExpiration)
convertAttributes(o.Inode, &o.Attributes, &out.Attr)
case *fuseops.MkDirOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.CreateFileOp:
eSize := fusekernel.EntryOutSize(c.protocol)
e := (*fusekernel.EntryOut)(m.Grow(eSize))
convertChildInodeEntry(&o.Entry, e)
oo := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
oo.Fh = uint64(o.Handle)
case *fuseops.CreateSymlinkOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.RenameOp:
// Empty response
case *fuseops.RmDirOp:
// Empty response
case *fuseops.UnlinkOp:
// Empty response
case *fuseops.OpenDirOp:
out := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
out.Fh = uint64(o.Handle)
case *fuseops.ReadDirOp:
// convertInMessage already set up the destination buffer to be at the end
// of the out message. We need only shrink to the right size based on how
// much the user read.
m.ShrinkTo(buffer.OutMessageInitialSize + uintptr(o.BytesRead))
case *fuseops.ReleaseDirHandleOp:
// Empty response
case *fuseops.OpenFileOp:
out := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
out.Fh = uint64(o.Handle)
if o.KeepPageCache {
out.OpenFlags |= uint32(fusekernel.OpenKeepCache)
}
case *fuseops.ReadFileOp:
// convertInMessage already set up the destination buffer to be at the end
// of the out message. We need only shrink to the right size based on how
// much the user read.
m.ShrinkTo(buffer.OutMessageInitialSize + uintptr(o.BytesRead))
case *fuseops.WriteFileOp:
out := (*fusekernel.WriteOut)(m.Grow(unsafe.Sizeof(fusekernel.WriteOut{})))
out.Size = uint32(len(o.Data))
case *fuseops.SyncFileOp:
// Empty response
case *fuseops.FlushFileOp:
// Empty response
case *fuseops.ReleaseFileHandleOp:
// Empty response
case *fuseops.ReadSymlinkOp:
m.AppendString(o.Target)
case *statFSOp:
m.Grow(unsafe.Sizeof(fusekernel.StatfsOut{}))
case *initOp:
out := (*fusekernel.InitOut)(m.Grow(unsafe.Sizeof(fusekernel.InitOut{})))
out.Major = o.Library.Major
out.Minor = o.Library.Minor
out.MaxReadahead = o.MaxReadahead
out.Flags = uint32(o.Flags)
out.MaxWrite = o.MaxWrite
default:
panic(fmt.Sprintf("Unexpected op: %#v", op))
}
return
}
// Like kernelResponse, but assumes the user replied with a nil error to the
// op.
func (c *Connection) kernelResponseForOp(
m *buffer.OutMessage,
op interface{}) {
// Create the appropriate output message
switch o := op.(type) {
case *fuseops.LookUpInodeOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.GetInodeAttributesOp:
size := fusekernel.AttrOutSize(c.protocol)
out := (*fusekernel.AttrOut)(m.Grow(size))
out.AttrValid, out.AttrValidNsec = convertExpirationTime(
o.AttributesExpiration)
convertAttributes(o.Inode, &o.Attributes, &out.Attr)
case *fuseops.SetInodeAttributesOp:
size := fusekernel.AttrOutSize(c.protocol)
out := (*fusekernel.AttrOut)(m.Grow(size))
out.AttrValid, out.AttrValidNsec = convertExpirationTime(
o.AttributesExpiration)
convertAttributes(o.Inode, &o.Attributes, &out.Attr)
case *fuseops.MkDirOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.CreateFileOp:
eSize := fusekernel.EntryOutSize(c.protocol)
e := (*fusekernel.EntryOut)(m.Grow(eSize))
convertChildInodeEntry(&o.Entry, e)
oo := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
oo.Fh = uint64(o.Handle)
case *fuseops.CreateSymlinkOp:
size := fusekernel.EntryOutSize(c.protocol)
out := (*fusekernel.EntryOut)(m.Grow(size))
convertChildInodeEntry(&o.Entry, out)
case *fuseops.RenameOp:
// Empty response
case *fuseops.RmDirOp:
// Empty response
case *fuseops.UnlinkOp:
// Empty response
case *fuseops.OpenDirOp:
out := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
out.Fh = uint64(o.Handle)
case *fuseops.ReadDirOp:
// convertInMessage already set up the destination buffer to be at the end
// of the out message. We need only shrink to the right size based on how
// much the user read.
m.ShrinkTo(buffer.OutMessageInitialSize + uintptr(o.BytesRead))
case *fuseops.ReleaseDirHandleOp:
// Empty response
case *fuseops.OpenFileOp:
out := (*fusekernel.OpenOut)(m.Grow(unsafe.Sizeof(fusekernel.OpenOut{})))
out.Fh = uint64(o.Handle)
if o.KeepPageCache {
out.OpenFlags |= uint32(fusekernel.OpenKeepCache)
}
case *fuseops.ReadFileOp:
// convertInMessage already set up the destination buffer to be at the end
// of the out message. We need only shrink to the right size based on how
// much the user read.
m.ShrinkTo(buffer.OutMessageInitialSize + uintptr(o.BytesRead))
case *fuseops.WriteFileOp:
out := (*fusekernel.WriteOut)(m.Grow(unsafe.Sizeof(fusekernel.WriteOut{})))
out.Size = uint32(len(o.Data))
case *fuseops.SyncFileOp:
// Empty response
case *fuseops.FlushFileOp:
// Empty response
case *fuseops.ReleaseFileHandleOp:
// Empty response
case *fuseops.ReadSymlinkOp:
m.AppendString(o.Target)
case *fuseops.StatFSOp:
out := (*fusekernel.StatfsOut)(m.Grow(unsafe.Sizeof(fusekernel.StatfsOut{})))
out.St.Blocks = o.Blocks
out.St.Bfree = o.BlocksFree
out.St.Bavail = o.BlocksAvailable
out.St.Files = o.Inodes
out.St.Ffree = o.InodesFree
// The posix spec for sys/statvfs.h (http://goo.gl/LktgrF) defines the
// following fields of statvfs, among others:
//
// f_bsize File system block size.
// f_frsize Fundamental file system block size.
// f_blocks Total number of blocks on file system in units of f_frsize.
//
// It appears as though f_bsize was the only thing supported by most unixes
// originally, but then f_frsize was added when new sorts of file systems
// came about. Quoth The Linux Programming Interface by Michael Kerrisk
// (https://goo.gl/5LZMxQ):
//
// For most Linux file systems, the values of f_bsize and f_frsize are
// the same. However, some file systems support the notion of block
// fragments, which can be used to allocate a smaller unit of storage
// at the end of the file if if a full block is not required. This
// avoids the waste of space that would otherwise occur if a full block
// was allocated. On such file systems, f_frsize is the size of a
// fragment, and f_bsize is the size of a whole block. (The notion of
// fragments in UNIX file systems first appeared in the early 1980s
// with the 4.2BSD Fast File System.)
//
// Confusingly, it appears as though osxfuse surfaces fuse_kstatfs::bsize
// as statfs::f_iosize (of advisory use only), and fuse_kstatfs::frsize as
// statfs::f_bsize (which affects free space display in the Finder).
out.St.Bsize = o.IoSize
out.St.Frsize = o.BlockSize
case *initOp:
out := (*fusekernel.InitOut)(m.Grow(unsafe.Sizeof(fusekernel.InitOut{})))
out.Major = o.Library.Major
out.Minor = o.Library.Minor
out.MaxReadahead = o.MaxReadahead
out.Flags = uint32(o.Flags)
out.MaxWrite = o.MaxWrite
default:
panic(fmt.Sprintf("Unexpected op: %#v", op))
}
return
}