зеркало из https://github.com/mozilla/gecko-dev.git
163 строки
4.1 KiB
C++
163 строки
4.1 KiB
C++
/* -*- Mode: C++; tab-width: 50; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
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#if defined(XP_WIN)
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#include <windows.h>
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#include <objbase.h>
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#elif defined(XP_MACOSX)
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#include <CoreFoundation/CoreFoundation.h>
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#else
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#include <stdlib.h>
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#include "prrng.h"
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#endif
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#include "nsMemory.h"
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#include "nsUUIDGenerator.h"
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using namespace mozilla;
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NS_IMPL_ISUPPORTS1(nsUUIDGenerator, nsIUUIDGenerator)
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nsUUIDGenerator::nsUUIDGenerator()
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: mLock("nsUUIDGenerator.mLock")
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{
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}
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nsUUIDGenerator::~nsUUIDGenerator()
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{
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}
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nsresult
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nsUUIDGenerator::Init()
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{
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// We're a service, so we're guaranteed that Init() is not going
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// to be reentered while we're inside Init().
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#if !defined(XP_WIN) && !defined(XP_MACOSX) && !defined(ANDROID)
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/* initialize random number generator using NSPR random noise */
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unsigned int seed;
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size_t bytes = 0;
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while (bytes < sizeof(seed)) {
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size_t nbytes = PR_GetRandomNoise(((unsigned char *)&seed)+bytes,
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sizeof(seed)-bytes);
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if (nbytes == 0) {
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return NS_ERROR_FAILURE;
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}
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bytes += nbytes;
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}
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/* Initialize a new RNG state, and immediately switch
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* back to the previous one -- we want to use mState
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* only for our own calls to random().
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*/
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mSavedState = initstate(seed, mState, sizeof(mState));
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setstate(mSavedState);
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mRBytes = 4;
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#ifdef RAND_MAX
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if ((unsigned long) RAND_MAX < (unsigned long)0xffffffff)
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mRBytes = 3;
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if ((unsigned long) RAND_MAX < (unsigned long)0x00ffffff)
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mRBytes = 2;
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if ((unsigned long) RAND_MAX < (unsigned long)0x0000ffff)
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mRBytes = 1;
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if ((unsigned long) RAND_MAX < (unsigned long)0x000000ff)
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return NS_ERROR_FAILURE;
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#endif
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#endif /* non XP_WIN and non XP_MACOSX */
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return NS_OK;
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}
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NS_IMETHODIMP
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nsUUIDGenerator::GenerateUUID(nsID** ret)
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{
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nsID *id = static_cast<nsID*>(NS_Alloc(sizeof(nsID)));
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if (id == nullptr)
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return NS_ERROR_OUT_OF_MEMORY;
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nsresult rv = GenerateUUIDInPlace(id);
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if (NS_FAILED(rv)) {
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NS_Free(id);
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return rv;
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}
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*ret = id;
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return rv;
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}
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NS_IMETHODIMP
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nsUUIDGenerator::GenerateUUIDInPlace(nsID* id)
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{
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// The various code in this method is probably not threadsafe, so lock
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// across the whole method.
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MutexAutoLock lock(mLock);
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#if defined(XP_WIN)
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HRESULT hr = CoCreateGuid((GUID*)id);
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if (FAILED(hr))
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return NS_ERROR_FAILURE;
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#elif defined(XP_MACOSX)
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CFUUIDRef uuid = CFUUIDCreate(kCFAllocatorDefault);
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if (!uuid)
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return NS_ERROR_FAILURE;
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CFUUIDBytes bytes = CFUUIDGetUUIDBytes(uuid);
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memcpy(id, &bytes, sizeof(nsID));
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CFRelease(uuid);
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#else /* not windows or OS X; generate randomness using random(). */
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/* XXX we should be saving the return of setstate here and switching
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* back to it; instead, we use the value returned when we called
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* initstate, since older glibc's have broken setstate() return values
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*/
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#ifndef ANDROID
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setstate(mState);
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#endif
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size_t bytesLeft = sizeof(nsID);
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while (bytesLeft > 0) {
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#ifdef ANDROID
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long rval = arc4random();
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const size_t mRBytes = 4;
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#else
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long rval = random();
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#endif
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uint8_t *src = (uint8_t*)&rval;
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// We want to grab the mRBytes least significant bytes of rval, since
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// mRBytes less than sizeof(rval) means the high bytes are 0.
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#ifdef IS_BIG_ENDIAN
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src += sizeof(rval) - mRBytes;
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#endif
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uint8_t *dst = ((uint8_t*) id) + (sizeof(nsID) - bytesLeft);
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size_t toWrite = (bytesLeft < mRBytes ? bytesLeft : mRBytes);
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for (size_t i = 0; i < toWrite; i++)
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dst[i] = src[i];
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bytesLeft -= toWrite;
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}
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/* Put in the version */
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id->m2 &= 0x0fff;
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id->m2 |= 0x4000;
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/* Put in the variant */
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id->m3[0] &= 0x3f;
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id->m3[0] |= 0x80;
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#ifndef ANDROID
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/* Restore the previous RNG state */
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setstate(mSavedState);
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#endif
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#endif
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return NS_OK;
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}
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