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/*
* Copyright (C) 2022-2024 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. ``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
* 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 "JSCBytecodeCacheVersion.h"
#include <wtf/DataLog.h>
#include <wtf/HexNumber.h>
#include <wtf/NeverDestroyed.h>
#include <wtf/text/SuperFastHash.h>
#if OS(UNIX)
#include <dlfcn.h>
#if OS(DARWIN)
#include <mach-o/dyld.h>
#include <uuid/uuid.h>
#include <wtf/spi/darwin/dyldSPI.h>
#else
#include <link.h>
#endif
#endif
namespace JSC {
namespace JSCBytecodeCacheVersionInternal {
static constexpr bool verbose = false;
}
uint32_t computeJSCBytecodeCacheVersion()
{
UNUSED_VARIABLE(JSCBytecodeCacheVersionInternal::verbose);
static LazyNeverDestroyed<uint32_t> cacheVersion;
static std::once_flag onceFlag;
std::call_once(onceFlag, [] {
void* jsFunctionAddr = std::bit_cast<void*>(&computeJSCBytecodeCacheVersion);
#if OS(DARWIN)
uuid_t uuid;
if (const mach_header* header = dyld_image_header_containing_address(jsFunctionAddr); header && _dyld_get_image_uuid(header, uuid)) {
uuid_string_t uuidString = { };
uuid_unparse(uuid, uuidString);
cacheVersion.construct(SuperFastHash::computeHash(uuidString));
dataLogLnIf(JSCBytecodeCacheVersionInternal::verbose, "UUID of JavaScriptCore.framework:", uuidString);
return;
}
cacheVersion.construct(0);
dataLogLnIf(JSCBytecodeCacheVersionInternal::verbose, "Failed to get UUID for JavaScriptCore framework");
#elif OS(UNIX) && !PLATFORM(PLAYSTATION)
auto result = ([&] -> std::optional<uint32_t> {
Dl_info info { };
if (!dladdr(jsFunctionAddr, &info))
return std::nullopt;
if (!info.dli_fbase)
return std::nullopt;
struct DLParam {
void* start { nullptr };
std::span<const uint8_t> description;
};
DLParam param { };
param.start = info.dli_fbase;
if (!dl_iterate_phdr(static_cast<int(*)(struct dl_phdr_info*, size_t, void*)>(
[](struct dl_phdr_info* info, size_t, void* priv) -> int {
WTF_ALLOW_UNSAFE_BUFFER_USAGE_BEGIN // Unix port
auto* data = static_cast<DLParam*>(priv);
void* start = nullptr;
for (unsigned i = 0; i < info->dlpi_phnum; ++i) {
if (info->dlpi_phdr[i].p_type == PT_LOAD) {
start = std::bit_cast<void*>(static_cast<uintptr_t>(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr));
break;
}
}
if (start != data->start)
return 0;
for (unsigned i = 0; i < info->dlpi_phnum; ++i) {
if (info->dlpi_phdr[i].p_type != PT_NOTE)
continue;
// https://refspecs.linuxbase.org/elf/gabi4+/ch5.pheader.html#note_section
using NoteHeader = ElfW(Nhdr);
auto* payload = std::bit_cast<uint8_t*>(static_cast<uintptr_t>(info->dlpi_addr + info->dlpi_phdr[i].p_vaddr));
size_t length = info->dlpi_phdr[i].p_filesz;
for (size_t index = 0; index < length;) {
auto* cursor = payload + index;
if ((index + sizeof(NoteHeader)) > length)
return 0;
auto* note = std::bit_cast<NoteHeader*>(cursor);
size_t size = sizeof(NoteHeader) + roundUpToMultipleOf<4>(note->n_namesz) + roundUpToMultipleOf<4>(note->n_descsz);
if ((index + size) > length)
return 0;
auto* name = cursor + sizeof(NoteHeader);
auto* description = cursor + sizeof(NoteHeader) + roundUpToMultipleOf<4>(note->n_namesz);
if (note->n_type == NT_GNU_BUILD_ID && note->n_descsz != 0 && note->n_namesz == 4 && memcmp(name, "GNU", 4) == 0) {
// Found build-id note.
data->description = std::span { description, note->n_descsz };
return 1;
}
index += size;
}
}
return 0;
WTF_ALLOW_UNSAFE_BUFFER_USAGE_END
}), ¶m))
return std::nullopt;
if (param.description.empty())
return std::nullopt;
if constexpr (JSCBytecodeCacheVersionInternal::verbose) {
for (uint8_t value : param.description)
dataLog(hex(value));
dataLogLn("");
}
return SuperFastHash::computeHash(param.description);
}());
if (result) {
cacheVersion.construct(result.value());
return;
}
cacheVersion.construct(0);
dataLogLnIf(JSCBytecodeCacheVersionInternal::verbose, "Failed to get UUID for JavaScriptCore framework");
#else
UNUSED_VARIABLE(jsFunctionAddr);
static constexpr uint32_t precomputedCacheVersion = SuperFastHash::computeHash(__TIMESTAMP__);
cacheVersion.construct(precomputedCacheVersion);
#endif
});
return cacheVersion.get();
}
} // namespace JSC
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