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-rw-r--r--JavaScriptCore/wtf/OSAllocatorPosix.cpp121
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diff --git a/JavaScriptCore/wtf/OSAllocatorPosix.cpp b/JavaScriptCore/wtf/OSAllocatorPosix.cpp
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--- a/JavaScriptCore/wtf/OSAllocatorPosix.cpp
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-/*
- * Copyright (C) 2010 Apple Inc. All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or without
- * modification, are permitted provided that the following conditions
- * are met:
- * 1. Redistributions of source code must retain the above copyright
- * notice, this list of conditions and the following disclaimer.
- * 2. Redistributions in binary form must reproduce the above copyright
- * notice, this list of conditions and the following disclaimer in the
- * documentation and/or other materials provided with the distribution.
- *
- * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS''
- * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
- * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
- * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
- * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
- * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
- * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
- * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
- * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
- * THE POSSIBILITY OF SUCH DAMAGE.
- */
-
-#include "config.h"
-#include "OSAllocator.h"
-
-#include <errno.h>
-#include <sys/mman.h>
-#include <wtf/Assertions.h>
-#include <wtf/UnusedParam.h>
-
-namespace WTF {
-
-void* OSAllocator::reserveUncommitted(size_t bytes, Usage usage, bool writable, bool executable)
-{
- void* result = reserveAndCommit(bytes, usage, writable, executable);
-#if HAVE(MADV_FREE_REUSE)
- // To support the "reserve then commit" model, we have to initially decommit.
- while (madvise(result, bytes, MADV_FREE_REUSABLE) == -1 && errno == EAGAIN) { }
-#endif
- return result;
-}
-
-void* OSAllocator::reserveAndCommit(size_t bytes, Usage usage, bool writable, bool executable)
-{
- // All POSIX reservations start out logically committed.
- int protection = PROT_READ;
- if (writable)
- protection |= PROT_WRITE;
- if (executable)
- protection |= PROT_EXEC;
-
- int flags = MAP_PRIVATE | MAP_ANON;
-
-#if OS(DARWIN) && !defined(BUILDING_ON_TIGER)
- int fd = usage;
-#else
- int fd = -1;
-#endif
-
- void* result = 0;
-#if (OS(DARWIN) && CPU(X86_64))
- if (executable) {
- // Cook up an address to allocate at, using the following recipe:
- // 17 bits of zero, stay in userspace kids.
- // 26 bits of randomness for ASLR.
- // 21 bits of zero, at least stay aligned within one level of the pagetables.
- //
- // But! - as a temporary workaround for some plugin problems (rdar://problem/6812854),
- // for now instead of 2^26 bits of ASLR lets stick with 25 bits of randomization plus
- // 2^24, which should put up somewhere in the middle of userspace (in the address range
- // 0x200000000000 .. 0x5fffffffffff).
- intptr_t randomLocation = 0;
- randomLocation = arc4random() & ((1 << 25) - 1);
- randomLocation += (1 << 24);
- randomLocation <<= 21;
- result = reinterpret_cast<void*>(randomLocation);
- }
-#endif
-
- result = mmap(result, bytes, protection, flags, fd, 0);
- if (result == MAP_FAILED)
- CRASH();
- return result;
-}
-
-void OSAllocator::commit(void* address, size_t bytes, bool, bool)
-{
-#if HAVE(MADV_FREE_REUSE)
- while (madvise(address, bytes, MADV_FREE_REUSE) == -1 && errno == EAGAIN) { }
-#else
- // Non-MADV_FREE_REUSE reservations automatically commit on demand.
- UNUSED_PARAM(address);
- UNUSED_PARAM(bytes);
-#endif
-}
-
-void OSAllocator::decommit(void* address, size_t bytes)
-{
-#if HAVE(MADV_FREE_REUSE)
- while (madvise(address, bytes, MADV_FREE_REUSABLE) == -1 && errno == EAGAIN) { }
-#elif HAVE(MADV_FREE)
- while (madvise(address, bytes, MADV_FREE) == -1 && errno == EAGAIN) { }
-#elif HAVE(MADV_DONTNEED)
- while (madvise(address, bytes, MADV_DONTNEED) == -1 && errno == EAGAIN) { }
-#else
- UNUSED_PARAM(address);
- UNUSED_PARAM(bytes);
-#endif
-}
-
-void OSAllocator::releaseDecommitted(void* address, size_t bytes)
-{
- int result = munmap(address, bytes);
- if (result == -1)
- CRASH();
-}
-
-} // namespace WTF