81 lines
2.3 KiB
Go
81 lines
2.3 KiB
Go
package winapi
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import (
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"errors"
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"reflect"
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"syscall"
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"unsafe"
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"golang.org/x/sys/windows"
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)
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// Uint16BufferToSlice wraps a uint16 pointer-and-length into a slice
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// for easier interop with Go APIs
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func Uint16BufferToSlice(buffer *uint16, bufferLength int) (result []uint16) {
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hdr := (*reflect.SliceHeader)(unsafe.Pointer(&result))
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hdr.Data = uintptr(unsafe.Pointer(buffer))
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hdr.Cap = bufferLength
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hdr.Len = bufferLength
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return
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}
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// UnicodeString corresponds to UNICODE_STRING win32 struct defined here
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// https://docs.microsoft.com/en-us/windows/win32/api/ntdef/ns-ntdef-_unicode_string
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type UnicodeString struct {
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Length uint16
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MaximumLength uint16
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Buffer *uint16
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}
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// NTSTRSAFE_UNICODE_STRING_MAX_CCH is a constant defined in ntstrsafe.h. This value
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// denotes the maximum number of wide chars a path can have.
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const NTSTRSAFE_UNICODE_STRING_MAX_CCH = 32767
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//String converts a UnicodeString to a golang string
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func (uni UnicodeString) String() string {
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// UnicodeString is not guaranteed to be null terminated, therefore
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// use the UnicodeString's Length field
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return windows.UTF16ToString(Uint16BufferToSlice(uni.Buffer, int(uni.Length/2)))
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}
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// NewUnicodeString allocates a new UnicodeString and copies `s` into
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// the buffer of the new UnicodeString.
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func NewUnicodeString(s string) (*UnicodeString, error) {
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buf, err := windows.UTF16FromString(s)
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if err != nil {
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return nil, err
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}
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if len(buf) > NTSTRSAFE_UNICODE_STRING_MAX_CCH {
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return nil, syscall.ENAMETOOLONG
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}
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uni := &UnicodeString{
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// The length is in bytes and should not include the trailing null character.
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Length: uint16((len(buf) - 1) * 2),
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MaximumLength: uint16((len(buf) - 1) * 2),
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Buffer: &buf[0],
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}
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return uni, nil
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}
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// ConvertStringSetToSlice is a helper function used to convert the contents of
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// `buf` into a string slice. `buf` contains a set of null terminated strings
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// with an additional null at the end to indicate the end of the set.
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func ConvertStringSetToSlice(buf []byte) ([]string, error) {
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var results []string
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prev := 0
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for i := range buf {
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if buf[i] == 0 {
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if prev == i {
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// found two null characters in a row, return result
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return results, nil
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}
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results = append(results, string(buf[prev:i]))
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prev = i + 1
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}
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}
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return nil, errors.New("string set malformed: missing null terminator at end of buffer")
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}
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