MachOReaderDylib.hpp [plain text]
/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
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#ifndef __OBJECT_FILE_DYLIB_MACH_O__
#define __OBJECT_FILE_DYLIB_MACH_O__
#include <stdint.h>
#include <math.h>
#include <unistd.h>
#include <sys/param.h>
#include <vector>
#include <set>
#include <algorithm>
#include <ext/hash_map>
#include "MachOFileAbstraction.hpp"
#include "MachOTrie.hpp"
#include "ObjectFile.h"
//
//
// To implement architecture xxx, you must write template specializations for the following method:
// Reader<xxx>::validFile()
//
//
namespace mach_o {
namespace dylib {
// forward reference
template <typename A> class Reader;
class Segment : public ObjectFile::Segment
{
public:
Segment(const char* name) { fName = name; }
virtual const char* getName() const { return fName; }
virtual bool isContentReadable() const { return true; }
virtual bool isContentWritable() const { return false; }
virtual bool isContentExecutable() const { return false; }
private:
const char* fName;
};
//
// An ExportAtom has no content. It exists so that the linker can track which imported
// symbols came from which dynamic libraries.
//
template <typename A>
class ExportAtom : public ObjectFile::Atom
{
public:
virtual ObjectFile::Reader* getFile() const { return &fOwner; }
virtual bool getTranslationUnitSource(const char** dir, const char** name) const { return false; }
virtual const char* getName() const { return fName; }
virtual const char* getDisplayName() const { return fName; }
virtual Scope getScope() const { return ObjectFile::Atom::scopeGlobal; }
virtual DefinitionKind getDefinitionKind() const { return fWeakDefinition ? kExternalWeakDefinition : kExternalDefinition; }
virtual SymbolTableInclusion getSymbolTableInclusion() const { return ObjectFile::Atom::kSymbolTableIn; }
virtual bool dontDeadStrip() const { return false; }
virtual bool isZeroFill() const { return false; }
virtual bool isThumb() const { return false; }
virtual uint64_t getSize() const { return 0; }
virtual std::vector<ObjectFile::Reference*>& getReferences() const { return fgEmptyReferenceList; }
virtual bool mustRemainInSection() const { return false; }
virtual const char* getSectionName() const { return "._imports"; }
virtual Segment& getSegment() const { return fgImportSegment; }
virtual ObjectFile::Atom& getFollowOnAtom() const { return *((ObjectFile::Atom*)NULL); }
virtual uint32_t getOrdinal() const { return fOrdinal; }
virtual std::vector<ObjectFile::LineInfo>* getLineInfo() const { return NULL; }
virtual ObjectFile::Alignment getAlignment() const { return ObjectFile::Alignment(0); }
virtual void copyRawContent(uint8_t buffer[]) const {}
virtual void setScope(Scope) { }
protected:
friend class Reader<A>;
typedef typename A::P P;
ExportAtom(ObjectFile::Reader& owner, const char* name, bool weak, uint32_t ordinal)
: fOwner(owner), fName(name), fOrdinal(ordinal), fWeakDefinition(weak) {}
virtual ~ExportAtom() {}
ObjectFile::Reader& fOwner;
const char* fName;
uint32_t fOrdinal;
bool fWeakDefinition;
static std::vector<ObjectFile::Reference*> fgEmptyReferenceList;
static Segment fgImportSegment;
};
template <typename A>
Segment ExportAtom<A>::fgImportSegment("__LINKEDIT");
template <typename A>
std::vector<ObjectFile::Reference*> ExportAtom<A>::fgEmptyReferenceList;
class ImportReference : public ObjectFile::Reference
{
public:
ImportReference(const char* name)
: fTarget(NULL), fTargetName(strdup(name)) {}
virtual ~ImportReference() {}
virtual ObjectFile::Reference::TargetBinding getTargetBinding() const { return (fTarget==NULL) ? ObjectFile::Reference::kUnboundByName : ObjectFile::Reference::kBoundByName; }
virtual ObjectFile::Reference::TargetBinding getFromTargetBinding() const{ return ObjectFile::Reference::kDontBind; }
virtual uint8_t getKind() const { return 0; }
virtual uint64_t getFixUpOffset() const { return 0; }
virtual const char* getTargetName() const { return fTargetName; }
virtual ObjectFile::Atom& getTarget() const { return *((ObjectFile::Atom*)fTarget); }
virtual uint64_t getTargetOffset() const { return 0; }
virtual ObjectFile::Atom& getFromTarget() const { return *((ObjectFile::Atom*)NULL); }
virtual const char* getFromTargetName() const { return NULL; }
virtual uint64_t getFromTargetOffset() const { return 0; }
virtual void setTarget(ObjectFile::Atom& atom, uint64_t offset) { fTarget = &atom; }
virtual void setFromTarget(ObjectFile::Atom&) { throw "can't set from target"; }
virtual const char* getDescription() const { return "dylib import reference"; }
private:
const ObjectFile::Atom* fTarget;
const char* fTargetName;
};
//
// An ImportAtom has no content. It exists so that when linking a main executable flat-namespace
// the imports of all flat dylibs are checked
//
template <typename A>
class ImportAtom : public ObjectFile::Atom
{
public:
virtual ObjectFile::Reader* getFile() const { return &fOwner; }
virtual bool getTranslationUnitSource(const char** dir, const char** name) const { return false; }
virtual const char* getName() const { return "flat-imports"; }
virtual const char* getDisplayName() const { return "flat_namespace undefines"; }
virtual Scope getScope() const { return ObjectFile::Atom::scopeTranslationUnit; }
virtual DefinitionKind getDefinitionKind() const { return kRegularDefinition; }
virtual SymbolTableInclusion getSymbolTableInclusion() const { return ObjectFile::Atom::kSymbolTableNotIn; }
virtual bool dontDeadStrip() const { return false; }
virtual bool isZeroFill() const { return false; }
virtual bool isThumb() const { return false; }
virtual uint64_t getSize() const { return 0; }
virtual std::vector<ObjectFile::Reference*>& getReferences() const { return (std::vector<ObjectFile::Reference*>&)(fReferences); }
virtual bool mustRemainInSection() const { return false; }
virtual const char* getSectionName() const { return "._imports"; }
virtual Segment& getSegment() const { return fgImportSegment; }
virtual ObjectFile::Atom& getFollowOnAtom() const { return *((ObjectFile::Atom*)NULL); }
virtual uint32_t getOrdinal() const { return fOrdinal; }
virtual std::vector<ObjectFile::LineInfo>* getLineInfo() const { return NULL; }
virtual ObjectFile::Alignment getAlignment() const { return ObjectFile::Alignment(0); }
virtual void copyRawContent(uint8_t buffer[]) const {}
virtual void setScope(Scope) { }
protected:
friend class Reader<A>;
typedef typename A::P P;
ImportAtom(ObjectFile::Reader& owner, uint32_t ordinal, std::vector<const char*>& imports)
: fOwner(owner), fOrdinal(ordinal) { makeReferences(imports); }
virtual ~ImportAtom() {}
void makeReferences(std::vector<const char*>& imports) {
for (std::vector<const char*>::iterator it=imports.begin(); it != imports.end(); ++it) {
fReferences.push_back(new ImportReference(*it));
}
}
ObjectFile::Reader& fOwner;
uint32_t fOrdinal;
std::vector<ObjectFile::Reference*> fReferences;
static Segment fgImportSegment;
};
template <typename A>
Segment ImportAtom<A>::fgImportSegment("__LINKEDIT");
//
// The reader for a dylib extracts all exported symbols names from the memory-mapped
// dylib, builds a hash table, then unmaps the file. This is an important memory
// savings for large dylibs.
//
template <typename A>
class Reader : public ObjectFile::Reader
{
public:
static bool validFile(const uint8_t* fileContent, bool executableOrDylib);
Reader(const uint8_t* fileContent, uint64_t fileLength, const char* path,
const LibraryOptions& dylibOptions, const ObjectFile::ReaderOptions& options,
uint32_t ordinalBase);
virtual ~Reader() {}
virtual const char* getPath() { return fPath; }
virtual time_t getModificationTime() { return 0; }
virtual DebugInfoKind getDebugInfoKind() { return ObjectFile::Reader::kDebugInfoNone; }
virtual std::vector<class ObjectFile::Atom*>& getAtoms();
virtual std::vector<class ObjectFile::Atom*>* getJustInTimeAtomsFor(const char* name);
virtual std::vector<Stab>* getStabs() { return NULL; }
virtual ObjectFile::Reader::ObjcConstraint getObjCConstraint() { return fObjcContraint; }
virtual const char* getInstallPath() { return fDylibInstallPath; }
virtual uint32_t getTimestamp() { return fDylibTimeStamp; }
virtual uint32_t getCurrentVersion() { return fDylibtCurrentVersion; }
virtual uint32_t getCompatibilityVersion() { return fDylibCompatibilityVersion; }
virtual void processIndirectLibraries(DylibHander* handler);
virtual void setExplicitlyLinked() { fExplicitlyLinked = true; }
virtual bool explicitlyLinked() { return fExplicitlyLinked; }
virtual bool implicitlyLinked() { return fImplicitlyLinked; }
virtual bool providedExportAtom() { return fProvidedAtom; }
virtual const char* parentUmbrella() { return fParentUmbrella; }
virtual std::vector<const char*>* getAllowableClients();
virtual bool hasWeakExternals() { return fHasWeakExports; }
virtual bool deadStrippable() { return fDeadStrippable; }
virtual bool isLazyLoadedDylib() { return fLazyLoaded; }
virtual void setImplicitlyLinked() { fImplicitlyLinked = true; }
protected:
struct ReExportChain { ReExportChain* prev; Reader<A>* reader; };
void assertNoReExportCycles(ReExportChain*);
private:
typedef typename A::P P;
typedef typename A::P::E E;
class CStringEquals
{
public:
bool operator()(const char* left, const char* right) const { return (strcmp(left, right) == 0); }
};
struct AtomAndWeak { ObjectFile::Atom* atom; bool weak; uint32_t ordinal; };
typedef __gnu_cxx::hash_map<const char*, AtomAndWeak, __gnu_cxx::hash<const char*>, CStringEquals> NameToAtomMap;
typedef __gnu_cxx::hash_set<const char*, __gnu_cxx::hash<const char*>, CStringEquals> NameSet;
typedef typename NameToAtomMap::iterator NameToAtomMapIterator;
struct PathAndFlag { const char* path; bool reExport; };
bool isPublicLocation(const char* path);
void addSymbol(const char* name, bool weak);
void addDyldFastStub();
void buildExportHashTableFromExportInfo(const macho_dyld_info_command<P>* dyldInfo,
const uint8_t* fileContent);
void buildExportHashTableFromSymbolTable(const macho_dysymtab_command<P>* dynamicInfo,
const macho_nlist<P>* symbolTable, const char* strings,
const uint8_t* fileContent);
const char* fPath;
const char* fParentUmbrella;
std::vector<const char*> fAllowableClients;
const char* fDylibInstallPath;
uint32_t fDylibTimeStamp;
uint32_t fDylibtCurrentVersion;
uint32_t fDylibCompatibilityVersion;
uint32_t fReExportedOrdinal;
std::vector<PathAndFlag> fDependentLibraryPaths;
NameToAtomMap fAtoms;
NameSet fIgnoreExports;
bool fNoRexports;
bool fHasWeakExports;
bool fDeadStrippable;
const bool fLinkingFlat;
const bool fLinkingMainExecutable;
bool fExplictReExportFound;
bool fExplicitlyLinked;
bool fImplicitlyLinked;
bool fProvidedAtom;
bool fImplicitlyLinkPublicDylibs;
bool fLazyLoaded;
ObjectFile::Reader::ObjcConstraint fObjcContraint;
std::vector<ObjectFile::Reader*> fReExportedChildren;
const ObjectFile::ReaderOptions::MacVersionMin fDeploymentVersionMin;
std::vector<class ObjectFile::Atom*> fFlatImports;
static bool fgLogHashtable;
static std::vector<class ObjectFile::Atom*> fgEmptyAtomList;
};
template <typename A>
std::vector<class ObjectFile::Atom*> Reader<A>::fgEmptyAtomList;
template <typename A>
bool Reader<A>::fgLogHashtable = false;
template <typename A>
Reader<A>::Reader(const uint8_t* fileContent, uint64_t fileLength, const char* path,
const LibraryOptions& dylibOptions,
const ObjectFile::ReaderOptions& options, uint32_t ordinalBase)
: fParentUmbrella(NULL), fDylibInstallPath(NULL), fDylibTimeStamp(0), fDylibtCurrentVersion(0),
fDylibCompatibilityVersion(0), fReExportedOrdinal(ordinalBase), fLinkingFlat(options.fFlatNamespace),
fLinkingMainExecutable(options.fLinkingMainExecutable), fExplictReExportFound(false),
fExplicitlyLinked(false), fImplicitlyLinked(false), fProvidedAtom(false),
fImplicitlyLinkPublicDylibs(options.fImplicitlyLinkPublicDylibs), fLazyLoaded(dylibOptions.fLazyLoad),
fObjcContraint(ObjectFile::Reader::kObjcNone),
fDeploymentVersionMin(options.fMacVersionMin)
{
// sanity check
if ( ! validFile(fileContent, dylibOptions.fBundleLoader) )
throw "not a valid mach-o object file";
fPath = strdup(path);
const macho_header<P>* header = (const macho_header<P>*)fileContent;
const uint32_t cmd_count = header->ncmds();
const macho_load_command<P>* const cmds = (macho_load_command<P>*)((char*)header + sizeof(macho_header<P>));
const macho_load_command<P>* const cmdsEnd = (macho_load_command<P>*)((char*)header + sizeof(macho_header<P>) + header->sizeofcmds());
// write out path for -whatsloaded option
if ( options.fLogAllFiles )
printf("%s\n", path);
if ( options.fRootSafe && ((header->flags() & MH_ROOT_SAFE) == 0) )
warning("using -root_safe but linking against %s which is not root safe", path);
if ( options.fSetuidSafe && ((header->flags() & MH_SETUID_SAFE) == 0) )
warning("using -setuid_safe but linking against %s which is not setuid safe", path);
// a "blank" stub has zero load commands
if ( (header->filetype() == MH_DYLIB_STUB) && (cmd_count == 0) ) {
// no further processing needed
munmap((caddr_t)fileContent, fileLength);
return;
}
// optimize the case where we know there is no reason to look at indirect dylibs
fNoRexports = (header->flags() & MH_NO_REEXPORTED_DYLIBS);
fHasWeakExports = (header->flags() & MH_WEAK_DEFINES);
fDeadStrippable = (header->flags() & MH_DEAD_STRIPPABLE_DYLIB);
bool trackDependentLibraries = !fNoRexports || options.fFlatNamespace;
// pass 1 builds list of all dependent libraries
const macho_load_command<P>* cmd = cmds;
if ( trackDependentLibraries ) {
for (uint32_t i = 0; i < cmd_count; ++i) {
switch (cmd->cmd()) {
case LC_REEXPORT_DYLIB:
fExplictReExportFound = true;
// fall into next case
case LC_LOAD_DYLIB:
case LC_LOAD_WEAK_DYLIB:
PathAndFlag entry;
entry.path = strdup(((struct macho_dylib_command<P>*)cmd)->name());
entry.reExport = (cmd->cmd() == LC_REEXPORT_DYLIB);
fDependentLibraryPaths.push_back(entry);
break;
}
cmd = (const macho_load_command<P>*)(((char*)cmd)+cmd->cmdsize());
if ( cmd > cmdsEnd )
throwf("malformed dylb, load command #%d is outside size of load commands in %s", i, path);
}
}
// pass 2 determines re-export info
const macho_dysymtab_command<P>* dynamicInfo = NULL;
const macho_dyld_info_command<P>* dyldInfo = NULL;
const macho_nlist<P>* symbolTable = NULL;
const char* strings = NULL;
cmd = cmds;
for (uint32_t i = 0; i < cmd_count; ++i) {
switch (cmd->cmd()) {
case LC_SYMTAB:
{
const macho_symtab_command<P>* symtab = (macho_symtab_command<P>*)cmd;
symbolTable = (const macho_nlist<P>*)((char*)header + symtab->symoff());
strings = (char*)header + symtab->stroff();
}
break;
case LC_DYSYMTAB:
dynamicInfo = (macho_dysymtab_command<P>*)cmd;
break;
case LC_DYLD_INFO:
case LC_DYLD_INFO_ONLY:
dyldInfo = (macho_dyld_info_command<P>*)cmd;
break;
case LC_ID_DYLIB:
{
macho_dylib_command<P>* dylibID = (macho_dylib_command<P>*)cmd;
fDylibInstallPath = strdup(dylibID->name());
fDylibTimeStamp = dylibID->timestamp();
fDylibtCurrentVersion = dylibID->current_version();
fDylibCompatibilityVersion = dylibID->compatibility_version();
}
break;
case LC_SUB_UMBRELLA:
if ( trackDependentLibraries ) {
const char* frameworkLeafName = ((macho_sub_umbrella_command<P>*)cmd)->sub_umbrella();
for (typename std::vector<PathAndFlag>::iterator it = fDependentLibraryPaths.begin(); it != fDependentLibraryPaths.end(); it++) {
const char* dylibName = it->path;
const char* lastSlash = strrchr(dylibName, '/');
if ( (lastSlash != NULL) && (strcmp(&lastSlash[1], frameworkLeafName) == 0) )
it->reExport = true;
}
}
break;
case LC_SUB_LIBRARY:
if ( trackDependentLibraries) {
const char* dylibBaseName = ((macho_sub_library_command<P>*)cmd)->sub_library();
for (typename std::vector<PathAndFlag>::iterator it = fDependentLibraryPaths.begin(); it != fDependentLibraryPaths.end(); it++) {
const char* dylibName = it->path;
const char* lastSlash = strrchr(dylibName, '/');
const char* leafStart = &lastSlash[1];
if ( lastSlash == NULL )
leafStart = dylibName;
const char* firstDot = strchr(leafStart, '.');
int len = strlen(leafStart);
if ( firstDot != NULL )
len = firstDot - leafStart;
if ( strncmp(leafStart, dylibBaseName, len) == 0 )
it->reExport = true;
}
}
break;
case LC_SUB_FRAMEWORK:
fParentUmbrella = strdup(((macho_sub_framework_command<P>*)cmd)->umbrella());
break;
case macho_segment_command<P>::CMD:
// check for Objective-C info
if ( strcmp(((macho_segment_command<P>*)cmd)->segname(), "__OBJC") == 0 ) {
const macho_segment_command<P>* segment = (macho_segment_command<P>*)cmd;
const macho_section<P>* const sectionsStart = (macho_section<P>*)((char*)segment + sizeof(macho_segment_command<P>));
const macho_section<P>* const sectionsEnd = §ionsStart[segment->nsects()];
for (const macho_section<P>* sect=sectionsStart; sect < sectionsEnd; ++sect) {
if ( strcmp(sect->sectname(), "__image_info") == 0 ) {
// struct objc_image_info {
// uint32_t version; // initially 0
// uint32_t flags;
// };
// #define OBJC_IMAGE_SUPPORTS_GC 2
// #define OBJC_IMAGE_GC_ONLY 4
//
const uint32_t* contents = (uint32_t*)(&fileContent[sect->offset()]);
if ( (sect->size() >= 8) && (contents[0] == 0) ) {
uint32_t flags = E::get32(contents[1]);
if ( (flags & 4) == 4 )
fObjcContraint = ObjectFile::Reader::kObjcGC;
else if ( (flags & 2) == 2 )
fObjcContraint = ObjectFile::Reader::kObjcRetainReleaseOrGC;
else
fObjcContraint = ObjectFile::Reader::kObjcRetainRelease;
}
else if ( sect->size() > 0 ) {
warning("can't parse __OBJC/__image_info section in %s", fPath);
}
}
}
}
}
cmd = (const macho_load_command<P>*)(((char*)cmd)+cmd->cmdsize());
if ( cmd > cmdsEnd )
throwf("malformed dylb, load command #%d is outside size of load commands in %s", i, path);
}
// Process the rest of the commands here.
cmd = cmds;
for (uint32_t i = 0; i < cmd_count; ++i) {
switch (cmd->cmd()) {
case LC_SUB_CLIENT:
const char *temp = strdup(((macho_sub_client_command<P>*)cmd)->client());
fAllowableClients.push_back(temp);
break;
}
cmd = (const macho_load_command<P>*)(((char*)cmd)+cmd->cmdsize());
}
// validate minimal load commands
if ( (fDylibInstallPath == NULL) && ((header->filetype() == MH_DYLIB) || (header->filetype() == MH_DYLIB_STUB)) )
throwf("dylib %s missing LC_ID_DYLIB load command", path);
if ( symbolTable == NULL )
throw "binary missing LC_SYMTAB load command";
if ( dynamicInfo == NULL )
throw "binary missing LC_DYSYMTAB load command";
// if linking flat and this is a flat dylib, create one atom that references all imported symbols
if ( fLinkingFlat && fLinkingMainExecutable && ((header->flags() & MH_TWOLEVEL) == 0) ) {
std::vector<const char*> importNames;
importNames.reserve(dynamicInfo->nundefsym());
const macho_nlist<P>* start = &symbolTable[dynamicInfo->iundefsym()];
const macho_nlist<P>* end = &start[dynamicInfo->nundefsym()];
for (const macho_nlist<P>* sym=start; sym < end; ++sym) {
importNames.push_back(&strings[sym->n_strx()]);
}
fFlatImports.push_back(new ImportAtom<A>(*this, fReExportedOrdinal++, importNames));
}
// build hash table
if ( dyldInfo != NULL )
buildExportHashTableFromExportInfo(dyldInfo, fileContent);
else
buildExportHashTableFromSymbolTable(dynamicInfo, symbolTable, strings, fileContent);
// special case libSystem
if ( (fDylibInstallPath != NULL) && (strcmp(fDylibInstallPath, "/usr/lib/libSystem.B.dylib") == 0) )
addDyldFastStub();
// unmap file
munmap((caddr_t)fileContent, fileLength);
}
template <typename A>
void Reader<A>::buildExportHashTableFromSymbolTable(const macho_dysymtab_command<P>* dynamicInfo,
const macho_nlist<P>* symbolTable, const char* strings,
const uint8_t* fileContent)
{
if ( dynamicInfo->tocoff() == 0 ) {
if ( fgLogHashtable ) fprintf(stderr, "ld: building hashtable of %u toc entries for %s\n", dynamicInfo->nextdefsym(), this->getPath());
const macho_nlist<P>* start = &symbolTable[dynamicInfo->iextdefsym()];
const macho_nlist<P>* end = &start[dynamicInfo->nextdefsym()];
fAtoms.resize(dynamicInfo->nextdefsym()); // set initial bucket count
for (const macho_nlist<P>* sym=start; sym < end; ++sym) {
this->addSymbol(&strings[sym->n_strx()], (sym->n_desc() & N_WEAK_DEF) != 0);
}
}
else {
int32_t count = dynamicInfo->ntoc();
fAtoms.resize(count); // set initial bucket count
if ( fgLogHashtable ) fprintf(stderr, "ld: building hashtable of %u entries for %s\n", count, this->getPath());
const struct dylib_table_of_contents* toc = (dylib_table_of_contents*)(fileContent + dynamicInfo->tocoff());
for (int32_t i = 0; i < count; ++i) {
const uint32_t index = E::get32(toc[i].symbol_index);
const macho_nlist<P>* sym = &symbolTable[index];
this->addSymbol(&strings[sym->n_strx()], (sym->n_desc() & N_WEAK_DEF) != 0);
}
}
}
template <typename A>
void Reader<A>::buildExportHashTableFromExportInfo(const macho_dyld_info_command<P>* dyldInfo,
const uint8_t* fileContent)
{
if ( fgLogHashtable ) fprintf(stderr, "ld: building hashtable from export info in %s\n", this->getPath());
if ( dyldInfo->export_size() > 0 ) {
const uint8_t* start = fileContent + dyldInfo->export_off();
const uint8_t* end = &start[dyldInfo->export_size()];
std::vector<mach_o::trie::Entry> list;
parseTrie(start, end, list);
for (std::vector<mach_o::trie::Entry>::iterator it=list.begin(); it != list.end(); ++it)
this->addSymbol(it->name, it->flags & EXPORT_SYMBOL_FLAGS_WEAK_DEFINITION);
}
}
template <>
void Reader<x86_64>::addDyldFastStub()
{
addSymbol("dyld_stub_binder", false);
}
template <>
void Reader<x86>::addDyldFastStub()
{
addSymbol("dyld_stub_binder", false);
}
template <typename A>
void Reader<A>::addDyldFastStub()
{
// do nothing
}
template <typename A>
void Reader<A>::addSymbol(const char* name, bool weakDef)
{
//fprintf(stderr, "addSymbol() %s\n", name);
// symbols that start with $ld$ are meta-data to the static linker
// <rdar://problem/5182537> need way for ld and dyld to see different exported symbols in a dylib
if ( strncmp(name, "$ld$", 4) == 0 ) {
// $ld$ <action> $ <condition> $ <symbol-name>
const char* symAction = &name[4];
const char* symCond = strchr(symAction, '$');
if ( symCond != NULL ) {
ObjectFile::ReaderOptions::MacVersionMin symVersionCondition = ObjectFile::ReaderOptions::kMinMacVersionUnset;
if ( (strncmp(symCond, "$os10.", 6) == 0) && isdigit(symCond[6]) && (symCond[7] == '$') ) {
switch ( symCond[6] - '0' ) {
case 0:
case 1:
symVersionCondition = ObjectFile::ReaderOptions::k10_1;
break;
case 2:
symVersionCondition = ObjectFile::ReaderOptions::k10_2;
break;
case 3:
symVersionCondition = ObjectFile::ReaderOptions::k10_3;
break;
case 4:
symVersionCondition = ObjectFile::ReaderOptions::k10_4;
break;
case 5:
symVersionCondition = ObjectFile::ReaderOptions::k10_5;
break;
case 6:
symVersionCondition = ObjectFile::ReaderOptions::k10_6;
break;
}
const char* symName = strchr(&symCond[1], '$');
if ( symName != NULL ) {
++symName;
if ( fDeploymentVersionMin == symVersionCondition ) {
if ( strncmp(symAction, "hide$", 5) == 0 ) {
if ( fgLogHashtable ) fprintf(stderr, " adding %s to ignore set for %s\n", symName, this->getPath());
fIgnoreExports.insert(strdup(symName));
return;
}
else if ( strncmp(symAction, "add$", 4) == 0 ) {
this->addSymbol(symName, weakDef);
return;
}
else {
warning("bad symbol action: %s in dylib %s", name, this->getPath());
}
}
}
else {
warning("bad symbol name: %s in dylib %s", name, this->getPath());
}
}
else {
warning("bad symbol version: %s in dylib %s", name, this->getPath());
}
}
else {
warning("bad symbol condition: %s in dylib %s", name, this->getPath());
}
}
// add symbol as possible export if we are not supposed to ignore it
if ( fIgnoreExports.count(name) == 0 ) {
AtomAndWeak bucket;
bucket.atom = NULL;
bucket.weak = weakDef;
bucket.ordinal = fReExportedOrdinal++;
if ( fgLogHashtable ) fprintf(stderr, " adding %s to hash table for %s\n", name, this->getPath());
fAtoms[strdup(name)] = bucket;
}
}
template <typename A>
std::vector<class ObjectFile::Atom*>& Reader<A>::getAtoms()
{
return fFlatImports;
}
template <typename A>
std::vector<class ObjectFile::Atom*>* Reader<A>::getJustInTimeAtomsFor(const char* name)
{
// if supposed to ignore this export, then pretend I don't have it
if ( fIgnoreExports.count(name) != 0 )
return NULL;
std::vector<class ObjectFile::Atom*>* atoms = NULL;
NameToAtomMapIterator pos = fAtoms.find(name);
if ( pos != fAtoms.end() ) {
if ( pos->second.atom == NULL ) {
// instantiate atom and update hash table
pos->second.atom = new ExportAtom<A>(*this, name, pos->second.weak, pos->second.ordinal);
fProvidedAtom = true;
if ( fgLogHashtable ) fprintf(stderr, "getJustInTimeAtomsFor: %s found in %s\n", name, this->getPath());
}
// return a vector of one atom
atoms = new std::vector<class ObjectFile::Atom*>;
atoms->push_back(pos->second.atom);
}
else {
if ( fgLogHashtable ) fprintf(stderr, "getJustInTimeAtomsFor: %s NOT found in %s\n", name, this->getPath());
// look in children that I re-export
for (std::vector<ObjectFile::Reader*>::iterator it = fReExportedChildren.begin(); it != fReExportedChildren.end(); it++) {
//fprintf(stderr, "getJustInTimeAtomsFor: %s NOT found in %s, looking in child %s\n", name, this->getPath(), (*it)->getInstallPath());
std::vector<class ObjectFile::Atom*>* childAtoms = (*it)->getJustInTimeAtomsFor(name);
if ( childAtoms != NULL ) {
// make a new atom that says this reader is the owner
bool isWeakDef = (childAtoms->at(0)->getDefinitionKind() == ObjectFile::Atom::kExternalWeakDefinition);
// return a vector of one atom
ExportAtom<A>* newAtom = new ExportAtom<A>(*this, name, isWeakDef, fReExportedOrdinal++);
fProvidedAtom = true;
atoms = new std::vector<class ObjectFile::Atom*>;
atoms->push_back(newAtom);
delete childAtoms;
return atoms;
}
}
}
return atoms;
}
template <typename A>
bool Reader<A>::isPublicLocation(const char* path)
{
// -no_implicit_dylibs disables this optimization
if ( ! fImplicitlyLinkPublicDylibs )
return false;
// /usr/lib is a public location
if ( (strncmp(path, "/usr/lib/", 9) == 0) && (strchr(&path[9], '/') == NULL) )
return true;
// /System/Library/Frameworks/ is a public location
if ( strncmp(path, "/System/Library/Frameworks/", 27) == 0 ) {
const char* frameworkDot = strchr(&path[27], '.');
// but only top level framework
// /System/Library/Frameworks/Foo.framework/Versions/A/Foo ==> true
// /System/Library/Frameworks/Foo.framework/Resources/libBar.dylib ==> false
// /System/Library/Frameworks/Foo.framework/Frameworks/Bar.framework/Bar ==> false
// /System/Library/Frameworks/Foo.framework/Frameworks/Xfoo.framework/XFoo ==> false
if ( frameworkDot != NULL ) {
int frameworkNameLen = frameworkDot - &path[27];
if ( strncmp(&path[strlen(path)-frameworkNameLen-1], &path[26], frameworkNameLen+1) == 0 )
return true;
}
}
return false;
}
template <typename A>
void Reader<A>::processIndirectLibraries(DylibHander* handler)
{
if ( fLinkingFlat ) {
for (typename std::vector<PathAndFlag>::iterator it = fDependentLibraryPaths.begin(); it != fDependentLibraryPaths.end(); it++) {
handler->findDylib(it->path, this->getPath());
}
}
else if ( fNoRexports ) {
// MH_NO_REEXPORTED_DYLIBS bit set, then nothing to do
}
else {
// two-level, might have re-exports
for (typename std::vector<PathAndFlag>::iterator it = fDependentLibraryPaths.begin(); it != fDependentLibraryPaths.end(); it++) {
if ( it->reExport ) {
//fprintf(stderr, "processIndirectLibraries() parent=%s, child=%s\n", this->getInstallPath(), it->path);
// a LC_REEXPORT_DYLIB, LC_SUB_UMBRELLA or LC_SUB_LIBRARY says we re-export this child
ObjectFile::Reader* child = handler->findDylib(it->path, this->getPath());
if ( isPublicLocation(child->getInstallPath()) ) {
// promote this child to be automatically added as a direct dependent if this already is
if ( this->explicitlyLinked() || this->implicitlyLinked() ) {
//fprintf(stderr, "processIndirectLibraries() implicitly linking %s\n", child->getInstallPath());
((Reader<A>*)child)->setImplicitlyLinked();
}
else if ( child->explicitlyLinked() || child->implicitlyLinked() ) {
//fprintf(stderr, "processIndirectLibraries() parent is not directly linked, but child is, so no need to re-export child\n");
}
else {
fReExportedChildren.push_back(child);
//fprintf(stderr, "processIndirectLibraries() parent is not directly linked, so parent=%s will re-export child=%s\n", this->getInstallPath(), it->path);
}
}
else {
// add all child's symbols to me
fReExportedChildren.push_back(child);
//fprintf(stderr, "processIndirectLibraries() child is not public, so parent=%s will re-export child=%s\n", this->getInstallPath(), it->path);
}
}
else if ( !fExplictReExportFound ) {
// see if child contains LC_SUB_FRAMEWORK with my name
ObjectFile::Reader* child = handler->findDylib(it->path, this->getPath());
const char* parentUmbrellaName = ((Reader<A>*)child)->parentUmbrella();
if ( parentUmbrellaName != NULL ) {
const char* parentName = this->getPath();
const char* lastSlash = strrchr(parentName, '/');
if ( (lastSlash != NULL) && (strcmp(&lastSlash[1], parentUmbrellaName) == 0) ) {
// add all child's symbols to me
fReExportedChildren.push_back(child);
//fprintf(stderr, "processIndirectLibraries() umbrella=%s will re-export child=%s\n", this->getInstallPath(), it->path);
}
}
}
}
}
// check for re-export cycles
ReExportChain chain;
chain.prev = NULL;
chain.reader = this;
this->assertNoReExportCycles(&chain);
}
template <typename A>
void Reader<A>::assertNoReExportCycles(ReExportChain* prev)
{
// recursively check my re-exported dylibs
ReExportChain chain;
chain.prev = prev;
chain.reader = this;
for (std::vector<ObjectFile::Reader*>::iterator it = fReExportedChildren.begin(); it != fReExportedChildren.end(); it++) {
ObjectFile::Reader* child = *it;
// check child is not already in chain
for (ReExportChain* p = prev; p != NULL; p = p->prev) {
if ( p->reader == child ) {
throwf("cycle in dylib re-exports with %s", child->getPath());
}
}
((Reader<A>*)(*it))->assertNoReExportCycles(&chain);
}
}
template <typename A>
std::vector<const char*>* Reader<A>::getAllowableClients()
{
std::vector<const char*>* result = new std::vector<const char*>;
for (typename std::vector<const char*>::iterator it = fAllowableClients.begin();
it != fAllowableClients.end();
it++) {
result->push_back(*it);
}
return (fAllowableClients.size() != 0 ? result : NULL);
}
template <>
bool Reader<ppc>::validFile(const uint8_t* fileContent, bool executableOrDyliborBundle)
{
const macho_header<P>* header = (const macho_header<P>*)fileContent;
if ( header->magic() != MH_MAGIC )
return false;
if ( header->cputype() != CPU_TYPE_POWERPC )
return false;
switch ( header->filetype() ) {
case MH_DYLIB:
case MH_DYLIB_STUB:
return true;
case MH_BUNDLE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with bundle (MH_BUNDLE) only dylibs (MH_DYLIB)";
case MH_EXECUTE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with a main executable";
default:
return false;
}
}
template <>
bool Reader<ppc64>::validFile(const uint8_t* fileContent, bool executableOrDyliborBundle)
{
const macho_header<P>* header = (const macho_header<P>*)fileContent;
if ( header->magic() != MH_MAGIC_64 )
return false;
if ( header->cputype() != CPU_TYPE_POWERPC64 )
return false;
switch ( header->filetype() ) {
case MH_DYLIB:
case MH_DYLIB_STUB:
return true;
case MH_BUNDLE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with bundle (MH_BUNDLE) only dylibs (MH_DYLIB)";
case MH_EXECUTE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with a main executable";
default:
return false;
}
}
template <>
bool Reader<x86>::validFile(const uint8_t* fileContent, bool executableOrDyliborBundle)
{
const macho_header<P>* header = (const macho_header<P>*)fileContent;
if ( header->magic() != MH_MAGIC )
return false;
if ( header->cputype() != CPU_TYPE_I386 )
return false;
switch ( header->filetype() ) {
case MH_DYLIB:
case MH_DYLIB_STUB:
return true;
case MH_BUNDLE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with bundle (MH_BUNDLE) only dylibs (MH_DYLIB)";
case MH_EXECUTE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with a main executable";
default:
return false;
}
}
template <>
bool Reader<x86_64>::validFile(const uint8_t* fileContent, bool executableOrDyliborBundle)
{
const macho_header<P>* header = (const macho_header<P>*)fileContent;
if ( header->magic() != MH_MAGIC_64 )
return false;
if ( header->cputype() != CPU_TYPE_X86_64 )
return false;
switch ( header->filetype() ) {
case MH_DYLIB:
case MH_DYLIB_STUB:
return true;
case MH_BUNDLE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with bundle (MH_BUNDLE) only dylibs (MH_DYLIB)";
case MH_EXECUTE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with a main executable";
default:
return false;
}
}
template <>
bool Reader<arm>::validFile(const uint8_t* fileContent, bool executableOrDyliborBundle)
{
const macho_header<P>* header = (const macho_header<P>*)fileContent;
if ( header->magic() != MH_MAGIC )
return false;
if ( header->cputype() != CPU_TYPE_ARM )
return false;
switch ( header->filetype() ) {
case MH_DYLIB:
case MH_DYLIB_STUB:
return true;
case MH_BUNDLE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with bundle (MH_BUNDLE) only dylibs (MH_DYLIB)";
case MH_EXECUTE:
if ( executableOrDyliborBundle )
return true;
else
throw "can't link with a main executable";
default:
return false;
}
}
}; // namespace dylib
}; // namespace mach_o
#endif // __OBJECT_FILE_DYLIB_MACH_O__