| // Copyright 2010 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Windows cryptographically secure pseudorandom number |
| // generator. |
| |
| package rand |
| |
| import ( |
| "os" |
| "sync" |
| "syscall" |
| ) |
| |
| // Implemented by using Windows CryptoAPI 2.0. |
| |
| func init() { Reader = &rngReader{} } |
| |
| // A rngReader satisfies reads by reading from the Windows CryptGenRandom API. |
| type rngReader struct { |
| prov syscall.Handle |
| mu sync.Mutex |
| } |
| |
| func (r *rngReader) Read(b []byte) (n int, err os.Error) { |
| r.mu.Lock() |
| if r.prov == 0 { |
| const provType = syscall.PROV_RSA_FULL |
| const flags = syscall.CRYPT_VERIFYCONTEXT | syscall.CRYPT_SILENT |
| errno := syscall.CryptAcquireContext(&r.prov, nil, nil, provType, flags) |
| if errno != 0 { |
| r.mu.Unlock() |
| return 0, os.NewSyscallError("CryptAcquireContext", errno) |
| } |
| } |
| r.mu.Unlock() |
| errno := syscall.CryptGenRandom(r.prov, uint32(len(b)), &b[0]) |
| if errno != 0 { |
| return 0, os.NewSyscallError("CryptGenRandom", errno) |
| } |
| return len(b), nil |
| } |