1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/xpcom/base/nsUUIDGenerator.cpp Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,160 @@
1.4 +/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
1.5 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.6 + * License, v. 2.0. If a copy of the MPL was not distributed with this
1.7 + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
1.8 +
1.9 +#if defined(XP_WIN)
1.10 +#include <windows.h>
1.11 +#include <objbase.h>
1.12 +#elif defined(XP_MACOSX)
1.13 +#include <CoreFoundation/CoreFoundation.h>
1.14 +#else
1.15 +#include <stdlib.h>
1.16 +#include "prrng.h"
1.17 +#endif
1.18 +
1.19 +#include "nsUUIDGenerator.h"
1.20 +
1.21 +using namespace mozilla;
1.22 +
1.23 +NS_IMPL_ISUPPORTS(nsUUIDGenerator, nsIUUIDGenerator)
1.24 +
1.25 +nsUUIDGenerator::nsUUIDGenerator()
1.26 + : mLock("nsUUIDGenerator.mLock")
1.27 +{
1.28 +}
1.29 +
1.30 +nsUUIDGenerator::~nsUUIDGenerator()
1.31 +{
1.32 +}
1.33 +
1.34 +nsresult
1.35 +nsUUIDGenerator::Init()
1.36 +{
1.37 + // We're a service, so we're guaranteed that Init() is not going
1.38 + // to be reentered while we're inside Init().
1.39 +
1.40 +#if !defined(XP_WIN) && !defined(XP_MACOSX) && !defined(ANDROID)
1.41 + /* initialize random number generator using NSPR random noise */
1.42 + unsigned int seed;
1.43 +
1.44 + size_t bytes = 0;
1.45 + while (bytes < sizeof(seed)) {
1.46 + size_t nbytes = PR_GetRandomNoise(((unsigned char *)&seed)+bytes,
1.47 + sizeof(seed)-bytes);
1.48 + if (nbytes == 0) {
1.49 + return NS_ERROR_FAILURE;
1.50 + }
1.51 + bytes += nbytes;
1.52 + }
1.53 +
1.54 + /* Initialize a new RNG state, and immediately switch
1.55 + * back to the previous one -- we want to use mState
1.56 + * only for our own calls to random().
1.57 + */
1.58 + mSavedState = initstate(seed, mState, sizeof(mState));
1.59 + setstate(mSavedState);
1.60 +
1.61 + mRBytes = 4;
1.62 +#ifdef RAND_MAX
1.63 + if ((unsigned long) RAND_MAX < (unsigned long)0xffffffff)
1.64 + mRBytes = 3;
1.65 + if ((unsigned long) RAND_MAX < (unsigned long)0x00ffffff)
1.66 + mRBytes = 2;
1.67 + if ((unsigned long) RAND_MAX < (unsigned long)0x0000ffff)
1.68 + mRBytes = 1;
1.69 + if ((unsigned long) RAND_MAX < (unsigned long)0x000000ff)
1.70 + return NS_ERROR_FAILURE;
1.71 +#endif
1.72 +
1.73 +#endif /* non XP_WIN and non XP_MACOSX */
1.74 +
1.75 + return NS_OK;
1.76 +}
1.77 +
1.78 +NS_IMETHODIMP
1.79 +nsUUIDGenerator::GenerateUUID(nsID** ret)
1.80 +{
1.81 + nsID *id = static_cast<nsID*>(NS_Alloc(sizeof(nsID)));
1.82 + if (id == nullptr)
1.83 + return NS_ERROR_OUT_OF_MEMORY;
1.84 +
1.85 + nsresult rv = GenerateUUIDInPlace(id);
1.86 + if (NS_FAILED(rv)) {
1.87 + NS_Free(id);
1.88 + return rv;
1.89 + }
1.90 +
1.91 + *ret = id;
1.92 + return rv;
1.93 +}
1.94 +
1.95 +NS_IMETHODIMP
1.96 +nsUUIDGenerator::GenerateUUIDInPlace(nsID* id)
1.97 +{
1.98 + // The various code in this method is probably not threadsafe, so lock
1.99 + // across the whole method.
1.100 + MutexAutoLock lock(mLock);
1.101 +
1.102 +#if defined(XP_WIN)
1.103 + HRESULT hr = CoCreateGuid((GUID*)id);
1.104 + if (FAILED(hr))
1.105 + return NS_ERROR_FAILURE;
1.106 +#elif defined(XP_MACOSX)
1.107 + CFUUIDRef uuid = CFUUIDCreate(kCFAllocatorDefault);
1.108 + if (!uuid)
1.109 + return NS_ERROR_FAILURE;
1.110 +
1.111 + CFUUIDBytes bytes = CFUUIDGetUUIDBytes(uuid);
1.112 + memcpy(id, &bytes, sizeof(nsID));
1.113 +
1.114 + CFRelease(uuid);
1.115 +#else /* not windows or OS X; generate randomness using random(). */
1.116 + /* XXX we should be saving the return of setstate here and switching
1.117 + * back to it; instead, we use the value returned when we called
1.118 + * initstate, since older glibc's have broken setstate() return values
1.119 + */
1.120 +#ifndef ANDROID
1.121 + setstate(mState);
1.122 +#endif
1.123 +
1.124 + size_t bytesLeft = sizeof(nsID);
1.125 + while (bytesLeft > 0) {
1.126 +#ifdef ANDROID
1.127 + long rval = arc4random();
1.128 + const size_t mRBytes = 4;
1.129 +#else
1.130 + long rval = random();
1.131 +#endif
1.132 +
1.133 +
1.134 + uint8_t *src = (uint8_t*)&rval;
1.135 + // We want to grab the mRBytes least significant bytes of rval, since
1.136 + // mRBytes less than sizeof(rval) means the high bytes are 0.
1.137 +#ifdef IS_BIG_ENDIAN
1.138 + src += sizeof(rval) - mRBytes;
1.139 +#endif
1.140 + uint8_t *dst = ((uint8_t*) id) + (sizeof(nsID) - bytesLeft);
1.141 + size_t toWrite = (bytesLeft < mRBytes ? bytesLeft : mRBytes);
1.142 + for (size_t i = 0; i < toWrite; i++)
1.143 + dst[i] = src[i];
1.144 +
1.145 + bytesLeft -= toWrite;
1.146 + }
1.147 +
1.148 + /* Put in the version */
1.149 + id->m2 &= 0x0fff;
1.150 + id->m2 |= 0x4000;
1.151 +
1.152 + /* Put in the variant */
1.153 + id->m3[0] &= 0x3f;
1.154 + id->m3[0] |= 0x80;
1.155 +
1.156 +#ifndef ANDROID
1.157 + /* Restore the previous RNG state */
1.158 + setstate(mSavedState);
1.159 +#endif
1.160 +#endif
1.161 +
1.162 + return NS_OK;
1.163 +}
