1 files changed, 164 insertions, 0 deletions
diff --git a/xpcom/base/nsUUIDGenerator.cpp b/xpcom/base/nsUUIDGenerator.cpp
new file mode 100644
index 0000000000..7b491db5cd
--- /dev/null
+++ b/xpcom/base/nsUUIDGenerator.cpp
@@ -0,0 +1,164 @@
+/* -*- 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;
+}