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102 lines
3.3 KiB
C++
102 lines
3.3 KiB
C++
//===--- ImageInspectionELF.cpp - ELF image inspection --------------------===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file includes routines that interact with ld*.so on ELF-based platforms
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// to extract runtime metadata embedded in dynamically linked ELF images
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// generated by the Swift compiler.
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//
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//===----------------------------------------------------------------------===//
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#if defined(__ELF__) || defined(__ANDROID__)
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#include "ImageInspection.h"
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#include <elf.h>
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#include <link.h>
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#include <dlfcn.h>
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#include <string.h>
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using namespace swift;
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/// The symbol name in the image that identifies the beginning of the
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/// protocol conformances table.
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static const char ProtocolConformancesSymbol[] =
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".swift2_protocol_conformances_start";
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/// The symbol name in the image that identifies the beginning of the
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/// type metadata record table.
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static const char TypeMetadataRecordsSymbol[] =
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".swift2_type_metadata_start";
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/// Context arguments passed down from dl_iterate_phdr to its callback.
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struct InspectArgs {
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/// Symbol name to look up.
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const char *symbolName;
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/// Callback function to invoke with the metadata block.
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void (*addBlock)(const void *start, uintptr_t size);
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};
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static int iteratePHDRCallback(struct dl_phdr_info *info,
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size_t size, void *data) {
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const InspectArgs *inspectArgs = reinterpret_cast<const InspectArgs *>(data);
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void *handle;
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if (!info->dlpi_name || info->dlpi_name[0] == '\0') {
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handle = dlopen(nullptr, RTLD_LAZY);
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} else {
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handle = dlopen(info->dlpi_name, RTLD_LAZY | RTLD_NOLOAD);
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}
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if (!handle) {
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// Not a shared library.
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return 0;
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}
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const char *conformances =
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reinterpret_cast<const char*>(dlsym(handle, inspectArgs->symbolName));
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if (!conformances) {
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// if there are no conformances, don't hold this handle open.
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dlclose(handle);
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return 0;
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}
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// Extract the size of the conformances block from the head of the section.
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uint64_t conformancesSize;
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memcpy(&conformancesSize, conformances, sizeof(conformancesSize));
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conformances += sizeof(conformancesSize);
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inspectArgs->addBlock(conformances, conformancesSize);
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dlclose(handle);
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return 0;
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}
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void swift::initializeProtocolConformanceLookup() {
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// Search the loaded dls. This only searches the already
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// loaded ones.
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// FIXME: Find a way to have this continue to happen for dlopen-ed images.
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// rdar://problem/19045112
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InspectArgs ProtocolConformanceArgs = {
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ProtocolConformancesSymbol,
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addImageProtocolConformanceBlockCallback
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};
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dl_iterate_phdr(iteratePHDRCallback, &ProtocolConformanceArgs);
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}
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void swift::initializeTypeMetadataRecordLookup() {
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InspectArgs TypeMetadataRecordArgs = {
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TypeMetadataRecordsSymbol,
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addImageTypeMetadataRecordBlockCallback
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};
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dl_iterate_phdr(iteratePHDRCallback, &TypeMetadataRecordArgs);
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}
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#endif // defined(__ELF__) || defined(__ANDROID__)
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