k3s/vendor/github.com/Microsoft/hcsshim/internal/winapi/utils.go
Brad Davidson b9cc6409f4 Bump containerd to v1.4.8-k3s1
Signed-off-by: Brad Davidson <brad.davidson@rancher.com>
2021-07-20 15:04:37 -07:00

76 lines
2.0 KiB
Go

package winapi
import (
"errors"
"reflect"
"syscall"
"unsafe"
"golang.org/x/sys/windows"
)
// Uint16BufferToSlice wraps a uint16 pointer-and-length into a slice
// for easier interop with Go APIs
func Uint16BufferToSlice(buffer *uint16, bufferLength int) (result []uint16) {
hdr := (*reflect.SliceHeader)(unsafe.Pointer(&result))
hdr.Data = uintptr(unsafe.Pointer(buffer))
hdr.Cap = bufferLength
hdr.Len = bufferLength
return
}
type UnicodeString struct {
Length uint16
MaximumLength uint16
Buffer *uint16
}
//String converts a UnicodeString to a golang string
func (uni UnicodeString) String() string {
// UnicodeString is not guaranteed to be null terminated, therefore
// use the UnicodeString's Length field
return syscall.UTF16ToString(Uint16BufferToSlice(uni.Buffer, int(uni.Length/2)))
}
// NewUnicodeString allocates a new UnicodeString and copies `s` into
// the buffer of the new UnicodeString.
func NewUnicodeString(s string) (*UnicodeString, error) {
// Get length of original `s` to use in the UnicodeString since the `buf`
// created later will have an additional trailing null character
length := len(s)
if length > 32767 {
return nil, syscall.ENAMETOOLONG
}
buf, err := windows.UTF16FromString(s)
if err != nil {
return nil, err
}
uni := &UnicodeString{
Length: uint16(length * 2),
MaximumLength: uint16(length * 2),
Buffer: &buf[0],
}
return uni, nil
}
// ConvertStringSetToSlice is a helper function used to convert the contents of
// `buf` into a string slice. `buf` contains a set of null terminated strings
// with an additional null at the end to indicate the end of the set.
func ConvertStringSetToSlice(buf []byte) ([]string, error) {
var results []string
prev := 0
for i := range buf {
if buf[i] == 0 {
if prev == i {
// found two null characters in a row, return result
return results, nil
}
results = append(results, string(buf[prev:i]))
prev = i + 1
}
}
return nil, errors.New("string set malformed: missing null terminator at end of buffer")
}