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/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#if defined(XP_WIN)
# include <windows.h>
# include <objbase.h>
#elif defined(XP_MACOSX)
# include <CoreFoundation/CoreFoundation.h>
#else
# include <stdlib.h>
# include "prrng.h"
#endif
#include "nsUUIDGenerator.h"
#ifdef ANDROID
extern "C" NS_EXPORT void arc4random_buf(void*, size_t);
#endif
using namespace mozilla;
NS_IMPL_ISUPPORTS(nsUUIDGenerator, nsIUUIDGenerator)
nsUUIDGenerator::nsUUIDGenerator() : mLock("nsUUIDGenerator.mLock") {}
nsUUIDGenerator::~nsUUIDGenerator() = default;
nsresult nsUUIDGenerator::Init() {
// We're a service, so we're guaranteed that Init() is not going
// to be reentered while we're inside Init().
#if !defined(XP_WIN) && !defined(XP_MACOSX) && !defined(HAVE_ARC4RANDOM)
/* initialize random number generator using NSPR random noise */
unsigned int seed;
size_t bytes = 0;
while (bytes < sizeof(seed)) {
size_t nbytes = PR_GetRandomNoise(((unsigned char*)&seed) + bytes,
sizeof(seed) - bytes);
if (nbytes == 0) {
return NS_ERROR_FAILURE;
}
bytes += nbytes;
}
/* Initialize a new RNG state, and immediately switch
* back to the previous one -- we want to use mState
* only for our own calls to random().
*/
mSavedState = initstate(seed, mState, sizeof(mState));
setstate(mSavedState);
mRBytes = 4;
# ifdef RAND_MAX
if ((unsigned long)RAND_MAX < 0xffffffffUL) {
mRBytes = 3;
}
if ((unsigned long)RAND_MAX < 0x00ffffffUL) {
mRBytes = 2;
}
if ((unsigned long)RAND_MAX < 0x0000ffffUL) {
mRBytes = 1;
}
if ((unsigned long)RAND_MAX < 0x000000ffUL) {
return NS_ERROR_FAILURE;
}
# endif
#endif /* non XP_WIN and non XP_MACOSX and non ARC4RANDOM */
return NS_OK;
}
NS_IMETHODIMP
nsUUIDGenerator::GenerateUUID(nsID** aRet) {
nsID* id = static_cast<nsID*>(moz_xmalloc(sizeof(nsID)));
nsresult rv = GenerateUUIDInPlace(id);
if (NS_FAILED(rv)) {
free(id);
return rv;
}
*aRet = id;
return rv;
}
NS_IMETHODIMP
nsUUIDGenerator::GenerateUUIDInPlace(nsID* aId) {
// The various code in this method is probably not threadsafe, so lock
// across the whole method.
MutexAutoLock lock(mLock);
#if defined(XP_WIN)
HRESULT hr = CoCreateGuid((GUID*)aId);
if (FAILED(hr)) {
return NS_ERROR_FAILURE;
}
#elif defined(XP_MACOSX)
CFUUIDRef uuid = CFUUIDCreate(kCFAllocatorDefault);
if (!uuid) {
return NS_ERROR_FAILURE;
}
CFUUIDBytes bytes = CFUUIDGetUUIDBytes(uuid);
memcpy(aId, &bytes, sizeof(nsID));
CFRelease(uuid);
#else /* not windows or OS X; generate randomness using random(). */
/* XXX we should be saving the return of setstate here and switching
* back to it; instead, we use the value returned when we called
* initstate, since older glibc's have broken setstate() return values
*/
# ifndef HAVE_ARC4RANDOM
setstate(mState);
# endif
# ifdef HAVE_ARC4RANDOM_BUF
arc4random_buf(aId, sizeof(nsID));
# else /* HAVE_ARC4RANDOM_BUF */
size_t bytesLeft = sizeof(nsID);
while (bytesLeft > 0) {
# ifdef HAVE_ARC4RANDOM
long rval = arc4random();
const size_t mRBytes = 4;
# else
long rval = random();
# endif
uint8_t* src = (uint8_t*)&rval;
// We want to grab the mRBytes least significant bytes of rval, since
// mRBytes less than sizeof(rval) means the high bytes are 0.
# ifdef IS_BIG_ENDIAN
src += sizeof(rval) - mRBytes;
# endif
uint8_t* dst = ((uint8_t*)aId) + (sizeof(nsID) - bytesLeft);
size_t toWrite = (bytesLeft < mRBytes ? bytesLeft : mRBytes);
for (size_t i = 0; i < toWrite; i++) {
dst[i] = src[i];
}
bytesLeft -= toWrite;
}
# endif /* HAVE_ARC4RANDOM_BUF */
/* Put in the version */
aId->m2 &= 0x0fff;
aId->m2 |= 0x4000;
/* Put in the variant */
aId->m3[0] &= 0x3f;
aId->m3[0] |= 0x80;
# ifndef HAVE_ARC4RANDOM
/* Restore the previous RNG state */
setstate(mSavedState);
# endif
#endif
return NS_OK;
}