[apple/dyld.git] / src / ImageLoader.cpp

/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
 *
 * Copyright (c) 2004-2006 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */

#define __STDC_LIMIT_MACROS
#include <stdint.h>
#include <errno.h>
#include <fcntl.h>
#include <mach/mach.h>
#include <mach-o/fat.h> 
#include <sys/types.h>
#include <sys/stat.h> 
#include <sys/mman.h>
#include <sys/param.h>
#include <sys/mount.h>
#include <libkern/OSAtomic.h>

#include "ImageLoader.h"

// in libc.a
extern "C" void _spin_lock(uint32_t*);
extern "C" void _spin_unlock(uint32_t*);

uint32_t                                                                ImageLoader::fgImagesUsedFromSharedCache = 0;
uint32_t                                                                ImageLoader::fgImagesWithUsedPrebinding = 0;
uint32_t                                                                ImageLoader::fgImagesRequiringNoFixups = 0;
uint32_t                                                                ImageLoader::fgTotalRebaseFixups = 0;
uint32_t                                                                ImageLoader::fgTotalBindFixups = 0;
uint32_t                                                                ImageLoader::fgTotalBindSymbolsResolved = 0;
uint32_t                                                                ImageLoader::fgTotalBindImageSearches = 0;
uint32_t                                                                ImageLoader::fgTotalLazyBindFixups = 0;
uint32_t                                                                ImageLoader::fgTotalPossibleLazyBindFixups = 0;
uint32_t                                                                ImageLoader::fgTotalSegmentsMapped = 0;
uint64_t                                                                ImageLoader::fgTotalBytesMapped = 0;
uint64_t                                                                ImageLoader::fgTotalBytesPreFetched = 0;
uint64_t                                                                ImageLoader::fgTotalLoadLibrariesTime;
uint64_t                                                                ImageLoader::fgTotalRebaseTime;
uint64_t                                                                ImageLoader::fgTotalBindTime;
uint64_t                                                                ImageLoader::fgTotalInitTime;
uintptr_t                                                               ImageLoader::fgNextSplitSegAddress = 0x90000000;
uint16_t                                                                ImageLoader::fgLoadOrdinal = 0;
uintptr_t                                                               Segment::fgNextPIEDylibAddress = 0;


void ImageLoader::init(const char* path, uint64_t offsetInFat, dev_t device, ino_t inode, time_t modDate)
{
        fPathHash = 0;
        fPath = path;
        fLogicalPath = NULL;
        fDevice = device;
        fInode = inode;
        fLastModified = modDate;
        fOffsetInFatFile = offsetInFat;
        fLibraries = NULL;
        fLibrariesCount = 0;
        fDlopenReferenceCount = 0;
        fStaticReferenceCount = 0;
        fDynamicReferenceCount = 0;
        fDynamicReferences = NULL;
        fDepth = 0;
        fLoadOrder = fgLoadOrdinal++;
        fState = 0;
        fAllLibraryChecksumsAndLoadAddressesMatch = false;
        fLeaveMapped = false;
        fNeverUnload = false;
        fHideSymbols = false;
        fMatchByInstallName = false;
        fRegisteredDOF = false;
#if IMAGE_NOTIFY_SUPPORT
        fAnnounced = false;
#endif
        fAllLazyPointersBound = false;
        fBeingRemoved = false;
        fAddFuncNotified = false;
        fPathOwnedByImage = false;
#if RECURSIVE_INITIALIZER_LOCK
        fInitializerRecursiveLock = NULL;
#else
        fInitializerLock = 0;
#endif
        if ( fPath != NULL )
                fPathHash = hash(fPath);
}


ImageLoader::ImageLoader(const char* path, uint64_t offsetInFat, const struct stat& info)
{
        init(path, offsetInFat, info.st_dev, info.st_ino, info.st_mtime);
}

ImageLoader::ImageLoader(const char* moduleName)
{
        init(moduleName, 0, 0, 0, 0);
}


ImageLoader::~ImageLoader()
{
        if ( fPathOwnedByImage && (fPath != NULL) ) 
                delete [] fPath;
        if ( fLogicalPath != NULL ) 
                delete [] fLogicalPath;
        if ( fLibraries != NULL ) {
                for (uint32_t i = 0; i < fLibrariesCount; ++i) {
                        if ( fLibraries[i].image != NULL )
                                fLibraries[i].image->fStaticReferenceCount--;
                }
                delete [] fLibraries;
        }
        if ( fDynamicReferences != NULL ) {
                for (std::set<const ImageLoader*>::iterator it = fDynamicReferences->begin(); it != fDynamicReferences->end(); ++it ) {
                        const_cast<ImageLoader*>(*it)->fDynamicReferenceCount--;
                }
                delete fDynamicReferences;
        }
}

void ImageLoader::setMapped(const LinkContext& context)
{
        fState = dyld_image_state_mapped;
        context.notifySingle(dyld_image_state_mapped, this->machHeader(), fPath, fLastModified);
}

void ImageLoader::addDynamicReference(const ImageLoader* target)
{
        if ( fDynamicReferences == NULL )
                fDynamicReferences = new std::set<const ImageLoader*>();
        if ( fDynamicReferences->count(target) == 0 ) { 
                fDynamicReferences->insert(target);
                const_cast<ImageLoader*>(target)->fDynamicReferenceCount++;
        }
        //dyld::log("dyld: addDynamicReference() from %s to %s, fDynamicReferences->size()=%lu\n", this->getPath(), target->getPath(), fDynamicReferences->size());
}

int ImageLoader::compare(const ImageLoader* right) const
{
        if ( this->fDepth == right->fDepth ) {
                if ( this->fLoadOrder == right->fLoadOrder )
                        return 0;
                else if ( this->fLoadOrder < right->fLoadOrder )
                        return -1;
                else
                        return 1;
        }
        else {
                if ( this->fDepth < right->fDepth )
                        return -1;
                else
                        return 1;
        }
}

void ImageLoader::setPath(const char* path)
{
        if ( fPathOwnedByImage && (fPath != NULL) ) 
                delete [] fPath;
        fPath = new char[strlen(path)+1];
        strcpy((char*)fPath, path);
        fPathOwnedByImage = true;  // delete fPath when this image is destructed
        fPathHash = hash(fPath);
}

void ImageLoader::setPathUnowned(const char* path)
{
        if ( fPathOwnedByImage && (fPath != NULL) ) {
                delete [] fPath;
        }
        fPath = path;
        fPathOwnedByImage = false;  
        fPathHash = hash(fPath);
}

void ImageLoader::setLogicalPath(const char* path)
{
        if ( fPath == NULL ) {
                // no physical path set yet, so use this path as physical
                this->setPath(path);
        }
        else if ( strcmp(path, fPath) == 0 ) {
                // do not set logical path because it is the same as the physical path
                fLogicalPath = NULL;
        }
        else {
                fLogicalPath = new char[strlen(path)+1];
                strcpy((char*)fLogicalPath, path);
        }
}

const char* ImageLoader::getLogicalPath() const
{
        if ( fLogicalPath != NULL )
                return fLogicalPath;
        else
                return fPath;
}

uint32_t ImageLoader::hash(const char* path)
{
        // this does not need to be a great hash
        // it is just used to reduce the number of strcmp() calls
        // of existing images when loading a new image
        uint32_t h = 0;
        for (const char* s=path; *s != '\0'; ++s)
                h = h*5 + *s;
        return h;
}

bool ImageLoader::matchInstallPath() const
{
        return fMatchByInstallName;
}

void ImageLoader::setMatchInstallPath(bool match)
{
        fMatchByInstallName = match;
}

bool ImageLoader::statMatch(const struct stat& stat_buf) const
{
        return ( (this->fDevice == stat_buf.st_dev) && (this->fInode == stat_buf.st_ino) );     
}

const char* ImageLoader::getShortName() const
{
        // try to return leaf name
        if ( fPath != NULL ) {
                const char* s = strrchr(fPath, '/');
                if ( s != NULL ) 
                        return &s[1];
        }
        return fPath; 
}

uint64_t ImageLoader::getOffsetInFatFile() const
{
        return fOffsetInFatFile;
}

void ImageLoader::setLeaveMapped()
{
        fLeaveMapped = true;
}

void ImageLoader::setHideExports(bool hide)
{
        fHideSymbols = hide;
}

bool ImageLoader::hasHiddenExports() const
{
        return fHideSymbols;
}

bool ImageLoader::isLinked() const
{
        return (fState >= dyld_image_state_bound);
}

time_t ImageLoader::lastModified() const
{
        return fLastModified;
}

bool ImageLoader::containsAddress(const void* addr) const
{
        if ( ! this->isLinked() )
                return false;
        for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
                Segment* seg = *it;
                const uint8_t* start = (const uint8_t*)seg->getActualLoadAddress(this);
                const uint8_t* end = start + seg->getSize();
                if ( (start <= addr) && (addr < end) && !seg->unaccessible() )
                        return true;
        }
        return false;
}

bool ImageLoader::overlapsWithAddressRange(const void* start, const void* end) const
{
        for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
                Segment* seg = *it;
                const uint8_t* segStart = (const uint8_t*)(seg->getActualLoadAddress(this));
                const uint8_t* segEnd = segStart + seg->getSize();
                if ( (start <= segStart) && (segStart < end) )
                        return true;
                if ( (start <= segEnd) && (segEnd < end) )
                        return true;
                if ( (segStart < start) && (end < segEnd) )
                        return true;
        }
        return false;
}

void ImageLoader::getMappedRegions(MappedRegion*& regions) const
{
        for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
                Segment* seg = *it;
                MappedRegion region;
                region.address = seg->getActualLoadAddress(this);
                region.size = seg->getSize();
                *regions++ = region;
        }
}


static bool notInImgageList(const ImageLoader* image, const ImageLoader** dsiStart, const ImageLoader** dsiCur)
{
        for (const ImageLoader** p = dsiStart; p < dsiCur; ++p)
                if ( *p == image )
                        return false;
        return true;
}


// private method that handles circular dependencies by only search any image once
const ImageLoader::Symbol* ImageLoader::findExportedSymbolInDependentImagesExcept(const char* name, 
                        const ImageLoader** dsiStart, const ImageLoader**& dsiCur, const ImageLoader** dsiEnd, const ImageLoader** foundIn) const
{
        const ImageLoader::Symbol* sym;
        
        // search self
        if ( notInImgageList(this, dsiStart, dsiCur) ) {
                sym = this->findExportedSymbol(name, NULL, false, foundIn);
                if ( sym != NULL )
                        return sym;
                *dsiCur++ = this;
        }

        // search directly dependent libraries
        for (uint32_t i=0; i < fLibrariesCount; ++i) {
                ImageLoader* dependentImage = fLibraries[i].image;
                if ( (dependentImage != NULL) && notInImgageList(dependentImage, dsiStart, dsiCur) ) {
                        const ImageLoader::Symbol* sym = dependentImage->findExportedSymbol(name, NULL, false, foundIn);
                        if ( sym != NULL )
                                return sym;
                }
        }
        
        // search indirectly dependent libraries
        for (uint32_t i=0; i < fLibrariesCount; ++i) {
                ImageLoader* dependentImage = fLibraries[i].image;
                if ( (dependentImage != NULL) && notInImgageList(dependentImage, dsiStart, dsiCur) ) {
                        *dsiCur++ = dependentImage; 
                        const ImageLoader::Symbol* sym = dependentImage->findExportedSymbolInDependentImagesExcept(name, dsiStart, dsiCur, dsiEnd, foundIn);
                        if ( sym != NULL )
                                return sym;
                }
        }

        return NULL;
}


const ImageLoader::Symbol* ImageLoader::findExportedSymbolInDependentImages(const char* name, const LinkContext& context, const ImageLoader** foundIn) const
{
        unsigned int imageCount = context.imageCount();
        const ImageLoader* dontSearchImages[imageCount];
        dontSearchImages[0] = this; // don't search this image
        const ImageLoader** cur = &dontSearchImages[1];
        return this->findExportedSymbolInDependentImagesExcept(name, &dontSearchImages[0], cur, &dontSearchImages[imageCount], foundIn);
}

const ImageLoader::Symbol* ImageLoader::findExportedSymbolInImageOrDependentImages(const char* name, const LinkContext& context, const ImageLoader** foundIn) const
{
        unsigned int imageCount = context.imageCount();
        const ImageLoader* dontSearchImages[imageCount];
        const ImageLoader** cur = &dontSearchImages[0];
        return this->findExportedSymbolInDependentImagesExcept(name, &dontSearchImages[0], cur, &dontSearchImages[imageCount], foundIn);
}


void ImageLoader::link(const LinkContext& context, bool forceLazysBound, bool preflightOnly, const RPathChain& loaderRPaths)
{
        //dyld::log("ImageLoader::link(%s) refCount=%d, neverUnload=%d\n", this->getPath(), fStaticReferenceCount, fNeverUnload);
        
        uint64_t t0 = mach_absolute_time();
        this->recursiveLoadLibraries(context,loaderRPaths);
        context.notifyBatch(dyld_image_state_dependents_mapped);
        
        // we only do the loading step for preflights
        if ( preflightOnly )
                return;
                
        uint64_t t1 = mach_absolute_time();
        context.clearAllDepths();
        this->recursiveUpdateDepth(context.imageCount());

        uint64_t t2 = mach_absolute_time();
        this->recursiveRebase(context);
        context.notifyBatch(dyld_image_state_rebased);
        
        uint64_t t3 = mach_absolute_time();
        this->recursiveBind(context, forceLazysBound);
        context.notifyBatch(dyld_image_state_bound);

        uint64_t t4 = mach_absolute_time();     
        std::vector<DOFInfo> dofs;
        this->recursiveGetDOFSections(context, dofs);
        context.registerDOFs(dofs);

        
        fgTotalLoadLibrariesTime += t1 - t0;
        fgTotalRebaseTime += t3 - t2;
        fgTotalBindTime += t4 - t3;
        
        // done with initial dylib loads
        Segment::fgNextPIEDylibAddress = 0;
}


void ImageLoader::printReferenceCounts()
{
        dyld::log("      dlopen=%d, static=%d, dynamic=%d for %s\n", 
                                fDlopenReferenceCount, fStaticReferenceCount, fDynamicReferenceCount, getPath() );
}


bool ImageLoader::decrementDlopenReferenceCount() 
{
        if ( fDlopenReferenceCount == 0 )
                return true;
        --fDlopenReferenceCount;
        return false;
}

void ImageLoader::runInitializers(const LinkContext& context)
{
#if IMAGE_NOTIFY_SUPPORT
        ImageLoader* newImages[context.imageCount()];
        ImageLoader** end = newImages;
        this->recursiveImageAnnouncement(context, end);  // build bottom up list images being added
        context.notifyAdding(newImages, end-newImages); // tell anyone who cares about these
#endif

        uint64_t t1 = mach_absolute_time();
        this->recursiveInitialization(context, mach_thread_self());
        context.notifyBatch(dyld_image_state_initialized);
        uint64_t t2 = mach_absolute_time();
        fgTotalInitTime += (t2 - t1);
}


void ImageLoader::bindAllLazyPointers(const LinkContext& context, bool recursive)
{
        if ( ! fAllLazyPointersBound ) {
                fAllLazyPointersBound = true;

                if ( recursive ) {
                        // bind lower level libraries first
                        for(unsigned int i=0; i < fLibrariesCount; ++i){
                                DependentLibrary& libInfo = fLibraries[i];
                                if ( libInfo.image != NULL )
                                        libInfo.image->bindAllLazyPointers(context, recursive);
                        }
                }
                // bind lazies in this image
                this->doBindJustLazies(context);
        }
}


intptr_t ImageLoader::assignSegmentAddresses(const LinkContext& context)
{
        // preflight and calculate slide if needed
        intptr_t slide = 0;
        if ( this->segmentsCanSlide() && this->segmentsMustSlideTogether() ) {
                bool needsToSlide = false;
                uintptr_t lowAddr = UINTPTR_MAX;
                uintptr_t highAddr = 0;
                for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
                        Segment* seg = *it;
                        const uintptr_t segLow = seg->getPreferredLoadAddress();
                        const uintptr_t segHigh = (segLow + seg->getSize() + 4095) & -4096;
                        if ( segLow < lowAddr )
                                lowAddr = segLow;
                        if ( segHigh > highAddr )
                                highAddr = segHigh;
                                
                        if ( !seg->hasPreferredLoadAddress() || !Segment::reserveAddressRange(seg->getPreferredLoadAddress(), seg->getSize()) )
                                needsToSlide = true;
                }
                if ( needsToSlide ) {
                        // find a chunk of address space to hold all segments
                        uintptr_t addr = Segment::reserveAnAddressRange(highAddr-lowAddr, context);
                        slide = addr - lowAddr;
                }
        } 
        else if ( ! this->segmentsCanSlide() ) {
                for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
                        Segment* seg = *it;
                        if ( strcmp(seg->getName(), "__PAGEZERO") == 0 )
                                continue;
                        if ( !Segment::reserveAddressRange(seg->getPreferredLoadAddress(), seg->getSize()) )
                                throw "can't map";
                }
        }
        else {
                // mach-o does not support independently sliding segments
        }
        return slide;
}


void ImageLoader::mapSegments(int fd, uint64_t offsetInFat, uint64_t lenInFat, uint64_t fileLen, const LinkContext& context)
{
        if ( context.verboseMapping )
                dyld::log("dyld: Mapping %s\n", this->getPath());
        // find address range for image
        intptr_t slide = this->assignSegmentAddresses(context);
        // map in all segments
        for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
                Segment* seg = *it;
                seg->map(fd, offsetInFat, slide, this, context);                
        }
        // update slide to reflect load location                        
        this->setSlide(slide);
}

void ImageLoader::mapSegments(const void* memoryImage, uint64_t imageLen, const LinkContext& context)
{
        if ( context.verboseMapping )
                dyld::log("dyld: Mapping memory %p\n", memoryImage);
        // find address range for image
        intptr_t slide = this->assignSegmentAddresses(context);
        // map in all segments
        for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
                Segment* seg = *it;
                seg->map(memoryImage, slide, this, context);            
        }
        // update slide to reflect load location                        
        this->setSlide(slide);
        // set R/W permissions on all segments at slide location
        for(ImageLoader::SegmentIterator it = this->beginSegments(); it != this->endSegments(); ++it ) {
                Segment* seg = *it;
                seg->setPermissions(context, this);             
        }
}

bool ImageLoader::allDependentLibrariesAsWhenPreBound() const
{
        return fAllLibraryChecksumsAndLoadAddressesMatch;
}


unsigned int ImageLoader::recursiveUpdateDepth(unsigned int maxDepth)
{
        // the purpose of this phase is to make the images sortable such that 
        // in a sort list of images, every image that an image depends on
        // occurs in the list before it.
        if ( fDepth == 0 ) {
                // break cycles
                fDepth = maxDepth;
                
                // get depth of dependents
                unsigned int minDependentDepth = maxDepth;
                for(unsigned int i=0; i < fLibrariesCount; ++i) {
                        DependentLibrary& libInfo = fLibraries[i];
                        if ( libInfo.image != NULL ) {
                                unsigned int d = libInfo.image->recursiveUpdateDepth(maxDepth);
                                if ( d < minDependentDepth )
                                        minDependentDepth = d;
                        }
                }
        
                // make me less deep then all my dependents
                fDepth = minDependentDepth - 1;
        }
        
        return fDepth;
}


void ImageLoader::recursiveLoadLibraries(const LinkContext& context, const RPathChain& loaderRPaths)
{
        if ( fState < dyld_image_state_dependents_mapped ) {
                // break cycles
                fState = dyld_image_state_dependents_mapped;
                
                // get list of libraries this image needs
                fLibrariesCount = this->doGetDependentLibraryCount();
                fLibraries = new DependentLibrary[fLibrariesCount];
                bzero(fLibraries, sizeof(DependentLibrary)*fLibrariesCount);
                DependentLibraryInfo libraryInfos[fLibrariesCount]; 
                this->doGetDependentLibraries(libraryInfos);
                
                // get list of rpaths that this image adds
                std::vector<const char*> rpathsFromThisImage;
                this->getRPaths(context, rpathsFromThisImage);
                const RPathChain thisRPaths(&loaderRPaths, &rpathsFromThisImage);
                
                // try to load each
                bool canUsePrelinkingInfo = true; 
                for(unsigned int i=0; i < fLibrariesCount; ++i){
                        DependentLibrary& requiredLib = fLibraries[i];
                        DependentLibraryInfo& requiredLibInfo = libraryInfos[i];
                        try {
                                bool depNamespace = false;
                                requiredLib.image = context.loadLibrary(requiredLibInfo.name, true, depNamespace, this->getPath(), &thisRPaths);
                                if ( requiredLib.image == this ) {
                                        // found circular reference, perhaps DYLD_LIBARY_PATH is causing this rdar://problem/3684168 
                                        requiredLib.image = context.loadLibrary(requiredLibInfo.name, false, depNamespace, NULL, NULL);
                                        if ( requiredLib.image != this )
                                                dyld::warn("DYLD_ setting caused circular dependency in %s\n", this->getPath());
                                }
                                if ( fNeverUnload )
                                        requiredLib.image->setNeverUnload();
                                requiredLib.image->fStaticReferenceCount += 1;
                                LibraryInfo actualInfo = requiredLib.image->doGetLibraryInfo();
                                requiredLib.required = requiredLibInfo.required;
                                requiredLib.checksumMatches = ( actualInfo.checksum == requiredLibInfo.info.checksum );
                                requiredLib.isReExported = requiredLibInfo.reExported;
                                if ( ! requiredLib.isReExported ) {
                                        requiredLib.isSubFramework = requiredLib.image->isSubframeworkOf(context, this);
                                        requiredLib.isReExported = requiredLib.isSubFramework || this->hasSubLibrary(context, requiredLib.image);
                                }
                                // check found library version is compatible
                                if ( actualInfo.minVersion < requiredLibInfo.info.minVersion ) {
                                        dyld::throwf("Incompatible library version: %s requires version %d.%d.%d or later, but %s provides version %d.%d.%d",
                                                        this->getShortName(), requiredLibInfo.info.minVersion >> 16, (requiredLibInfo.info.minVersion >> 8) & 0xff, requiredLibInfo.info.minVersion & 0xff,
                                                        requiredLib.image->getShortName(), actualInfo.minVersion >> 16, (actualInfo.minVersion >> 8) & 0xff, actualInfo.minVersion & 0xff);
                                }
                                // prebinding for this image disabled if any dependent library changed or slid
                                if ( !requiredLib.checksumMatches || (requiredLib.image->getSlide() != 0) )
                                        canUsePrelinkingInfo = false;
                                //if ( context.verbosePrebinding ) {
                                //      if ( !requiredLib.checksumMatches )
                                //              fprintf(stderr, "dyld: checksum mismatch, (%u v %u) for %s referencing %s\n", 
                                //                      requiredLibInfo.info.checksum, actualInfo.checksum, this->getPath(),    requiredLib.image->getPath());          
                                //      if ( requiredLib.image->getSlide() != 0 )
                                //              fprintf(stderr, "dyld: dependent library slid for %s referencing %s\n", this->getPath(), requiredLib.image->getPath());         
                                //}
                        }
                        catch (const char* msg) {
                                //if ( context.verbosePrebinding )
                                //      fprintf(stderr, "dyld: exception during processing for %s referencing %s\n", this->getPath(), requiredLib.image->getPath());            
                                if ( requiredLibInfo.required ) {
                                        fState = dyld_image_state_mapped;
                                        dyld::throwf("Library not loaded: %s\n  Referenced from: %s\n  Reason: %s", requiredLibInfo.name, this->getPath(), msg);
                                }
                                // ok if weak library not found
                                requiredLib.image = NULL;
                                canUsePrelinkingInfo = false;  // this disables all prebinding, we may want to just slam import vectors for this lib to zero
                        }
                }
                fAllLibraryChecksumsAndLoadAddressesMatch = canUsePrelinkingInfo;

                // tell each to load its dependents
                for(unsigned int i=0; i < fLibrariesCount; ++i){
                        DependentLibrary& lib = fLibraries[i];
                        if ( lib.image != NULL ) {      
                                lib.image->recursiveLoadLibraries(context, thisRPaths);
                        }
                }
                
                // do deep prebind check
                if ( fAllLibraryChecksumsAndLoadAddressesMatch ) {
                        for(unsigned int i=0; i < fLibrariesCount; ++i){
                                const DependentLibrary& libInfo = fLibraries[i];
                                if ( libInfo.image != NULL ) {
                                        if ( !libInfo.image->allDependentLibrariesAsWhenPreBound() )
                                                fAllLibraryChecksumsAndLoadAddressesMatch = false;
                                }
                        }
                }
                
                // free rpaths (getRPaths() malloc'ed each string)
                for(std::vector<const char*>::iterator it=rpathsFromThisImage.begin(); it != rpathsFromThisImage.end(); ++it) {
                        const char* str = *it;
                        free((void*)str);
                }
                
        }
}

void ImageLoader::recursiveRebase(const LinkContext& context)
{ 
        if ( fState < dyld_image_state_rebased ) {
                // break cycles
                fState = dyld_image_state_rebased;
                
                try {
                        // rebase lower level libraries first
                        for(unsigned int i=0; i < fLibrariesCount; ++i){
                                DependentLibrary& libInfo = fLibraries[i];
                                if ( libInfo.image != NULL )
                                        libInfo.image->recursiveRebase(context);
                        }
                                
                        // rebase this image
                        doRebase(context);
                        
                        // notify
                        context.notifySingle(dyld_image_state_rebased, this->machHeader(), fPath, fLastModified);
                }
                catch (const char* msg) {
                        // this image is not rebased
                        fState = dyld_image_state_dependents_mapped;
                        throw;
                }
        }
}




void ImageLoader::recursiveBind(const LinkContext& context, bool forceLazysBound)
{
        // Normally just non-lazy pointers are bound immediately.
        // The exceptions are:
        //   1) DYLD_BIND_AT_LAUNCH will cause lazy pointers to be bound immediately
        //   2) some API's (e.g. RTLD_NOW) can cause lazy pointers to be bound immediately
        if ( fState < dyld_image_state_bound ) {
                // break cycles
                fState = dyld_image_state_bound;
        
                try {
                        // bind lower level libraries first
                        for(unsigned int i=0; i < fLibrariesCount; ++i){
                                DependentLibrary& libInfo = fLibraries[i];
                                if ( libInfo.image != NULL )
                                        libInfo.image->recursiveBind(context, forceLazysBound);
                        }
                        // bind this image
                        this->doBind(context, forceLazysBound); 
                        this->doUpdateMappingPermissions(context);
                        // mark if lazys are also bound
                        if ( forceLazysBound || this->usablePrebinding(context) )
                                fAllLazyPointersBound = true;
                                
                        context.notifySingle(dyld_image_state_bound, this->machHeader(), fPath, fLastModified);
                }
                catch (const char* msg) {
                        // restore state
                        fState = dyld_image_state_rebased;
                        throw;
                }
        }
}


#if IMAGE_NOTIFY_SUPPORT
void ImageLoader::recursiveImageAnnouncement(const LinkContext& context, ImageLoader**& newImages)
{
        if ( ! fAnnounced ) {
                // break cycles
                fAnnounced = true;
                
                // announce lower level libraries first
                for(unsigned int i=0; i < fLibrariesCount; ++i){
                        DependentLibrary& libInfo = fLibraries[i];
                        if ( libInfo.image != NULL )
                                libInfo.image->recursiveImageAnnouncement(context, newImages);
                }
                
                // add to list of images to notify about
                *newImages++ = this;
                //dyld::log("next size = %d\n", newImages.size());
                
                // remember that this image wants to be notified about other images
                 if ( this->hasImageNotification() )
                        context.addImageNeedingNotification(this);
        }
}
#endif

void ImageLoader::recursiveGetDOFSections(const LinkContext& context, std::vector<DOFInfo>& dofs)
{
        if ( ! fRegisteredDOF ) {
                // break cycles
                fRegisteredDOF = true;
                
                // gather lower level libraries first
                for(unsigned int i=0; i < fLibrariesCount; ++i){
                        DependentLibrary& libInfo = fLibraries[i];
                        if ( libInfo.image != NULL )
                                libInfo.image->recursiveGetDOFSections(context, dofs);
                }
                this->doGetDOFSections(context, dofs);
        }
}


void ImageLoader::recursiveSpinLock(recursive_lock& rlock)
{
        // try to set image's ivar fInitializerRecursiveLock to point to this lock_info
        // keep trying until success (spin)
        while ( ! OSAtomicCompareAndSwapPtrBarrier(NULL, &rlock, (void**)&fInitializerRecursiveLock) ) {
                // if fInitializerRecursiveLock already points to a different lock_info, if it is for
                // the same thread we are on, the increment the lock count, otherwise continue to spin
                if ( (fInitializerRecursiveLock != NULL) && (fInitializerRecursiveLock->thread == rlock.thread) )
                        break;
        }
        ++(fInitializerRecursiveLock->count); 
}

void ImageLoader::recursiveSpinUnLock()
{
        if ( --(fInitializerRecursiveLock->count) == 0 )
                fInitializerRecursiveLock = NULL;
}


void ImageLoader::recursiveInitialization(const LinkContext& context, mach_port_t this_thread)
{
#if RECURSIVE_INITIALIZER_LOCK
        recursive_lock lock_info(this_thread);
        recursiveSpinLock(lock_info);
#else
        _spin_lock(&fInitializerLock);
#endif

        if ( fState < dyld_image_state_dependents_initialized-1 ) {
                uint8_t oldState = fState;
                // break cycles
                fState = dyld_image_state_dependents_initialized-1;

                try {
                        // initialize lower level libraries first
                        for(unsigned int i=0; i < fLibrariesCount; ++i){
                                DependentLibrary& libInfo = fLibraries[i];
                                // don't try to initialize stuff "above" me
                                if ( (libInfo.image != NULL) && (libInfo.image->fDepth >= fDepth) )
                                        libInfo.image->recursiveInitialization(context, this_thread);
                        }
                        
                        // record termination order
                        if ( this->needsTermination() )
                                context.terminationRecorder(this);
                        
                        // let objc know we are about to initalize this image
                        fState = dyld_image_state_dependents_initialized;
                        oldState = fState;
                        context.notifySingle(dyld_image_state_dependents_initialized, this->machHeader(), fPath, fLastModified);

                        // initialize this image
                        this->doInitialization(context);
                        // let anyone know we finished initalizing this image
                        fState = dyld_image_state_initialized;
                        oldState = fState;
                        context.notifySingle(dyld_image_state_initialized, this->machHeader(), fPath, fLastModified);
                }
                catch (const char* msg) {
                        // this image is not initialized
                        fState = oldState;
                #if RECURSIVE_INITIALIZER_LOCK
                        recursiveSpinUnLock();
                #else
                        _spin_unlock(&fInitializerLock);
                #endif
                        throw;
                }
        }
        
#if RECURSIVE_INITIALIZER_LOCK
        recursiveSpinUnLock();
#else
        _spin_unlock(&fInitializerLock);
#endif
}


static void printTime(const char* msg, uint64_t partTime, uint64_t totalTime)
{
        static uint64_t sUnitsPerSecond = 0;
        if ( sUnitsPerSecond == 0 ) {
                struct mach_timebase_info timeBaseInfo;
                if ( mach_timebase_info(&timeBaseInfo) == KERN_SUCCESS ) {
                        sUnitsPerSecond = 1000000000ULL * timeBaseInfo.denom / timeBaseInfo.numer;
                }
        }
        if ( partTime < sUnitsPerSecond ) {
                uint32_t milliSecondsTimeTen = (partTime*10000)/sUnitsPerSecond;
                uint32_t milliSeconds = milliSecondsTimeTen/10;
                uint32_t percentTimesTen = (partTime*1000)/totalTime;
                uint32_t percent = percentTimesTen/10;
                dyld::log("%s: %u.%u milliseconds (%u.%u%%)\n", msg, milliSeconds, milliSecondsTimeTen-milliSeconds*10, percent, percentTimesTen-percent*10);
        }
        else {
                uint32_t secondsTimeTen = (partTime*10)/sUnitsPerSecond;
                uint32_t seconds = secondsTimeTen/10;
                uint32_t percentTimesTen = (partTime*1000)/totalTime;
                uint32_t percent = percentTimesTen/10;
                dyld::log("%s: %u.%u seconds (%u.%u%%)\n", msg, seconds, secondsTimeTen-seconds*10, percent, percentTimesTen-percent*10);
        }
}

static char* commatize(uint64_t in, char* out)
{
        uint64_t div10 = in / 10;
        uint8_t delta = in - div10*10;
        char* s = &out[32];
        int digitCount = 1;
        *s = '\0';
        *(--s) = '0' + delta;
        in = div10;
        while ( in != 0 ) {
                if ( (digitCount % 3) == 0 )
                        *(--s) = ',';
                div10 = in / 10;
                delta = in - div10*10;
                *(--s) = '0' + delta;
                in = div10;
                ++digitCount;
        }
        return s;
}



void ImageLoader::printStatistics(unsigned int imageCount)
{
        uint64_t totalTime = fgTotalLoadLibrariesTime + fgTotalRebaseTime + fgTotalBindTime + fgTotalInitTime;
        char commaNum1[40];
        char commaNum2[40];

        printTime("total time", totalTime, totalTime);
        dyld::log("total images loaded:  %d (%u from dyld shared cache, %u needed no fixups)\n", imageCount, fgImagesUsedFromSharedCache, fgImagesRequiringNoFixups);
        dyld::log("total segments mapped: %u, into %llu pages with %llu pages pre-fetched\n", fgTotalSegmentsMapped, fgTotalBytesMapped/4096, fgTotalBytesPreFetched/4096);
        printTime("total images loading time", fgTotalLoadLibrariesTime, totalTime);
        dyld::log("total rebase fixups:  %s\n", commatize(fgTotalRebaseFixups, commaNum1));
        printTime("total rebase fixups time", fgTotalRebaseTime, totalTime);
        dyld::log("total binding fixups: %s\n", commatize(fgTotalBindFixups, commaNum1));
        if ( fgTotalBindSymbolsResolved != 0 ) {
                uint32_t avgTimesTen = (fgTotalBindImageSearches * 10) / fgTotalBindSymbolsResolved;
                uint32_t avgInt = fgTotalBindImageSearches / fgTotalBindSymbolsResolved;
                uint32_t avgTenths = avgTimesTen - (avgInt*10);
                dyld::log("total binding symbol lookups: %s, average images searched per symbol: %u.%u\n", 
                                commatize(fgTotalBindSymbolsResolved, commaNum1), avgInt, avgTenths);
        }
        printTime("total binding fixups time", fgTotalBindTime, totalTime);
        dyld::log("total bindings lazily fixed up: %s of %s\n", commatize(fgTotalLazyBindFixups, commaNum1), commatize(fgTotalPossibleLazyBindFixups, commaNum2));
        printTime("total init time time", fgTotalInitTime, totalTime);
}


//
// copy path and add suffix to result
//
//  /path/foo.dylib             _debug   =>   /path/foo_debug.dylib     
//  foo.dylib                   _debug   =>   foo_debug.dylib
//  foo                         _debug   =>   foo_debug
//  /path/bar                   _debug   =>   /path/bar_debug  
//  /path/bar.A.dylib   _debug   =>   /path/bar.A_debug.dylib
//
void ImageLoader::addSuffix(const char* path, const char* suffix, char* result)
{
        strcpy(result, path);
        
        char* start = strrchr(result, '/');
        if ( start != NULL )
                start++;
        else
                start = result;
                
        char* dot = strrchr(start, '.');
        if ( dot != NULL ) {
                strcpy(dot, suffix);
                strcat(&dot[strlen(suffix)], &path[dot-result]);
        }
        else {
                strcat(result, suffix);
        }
}


void Segment::map(int fd, uint64_t offsetInFatWrapper, intptr_t slide, const ImageLoader* image, const ImageLoader::LinkContext& context)
{
        vm_offset_t fileOffset = this->getFileOffset() + offsetInFatWrapper;
        vm_size_t size = this->getFileSize();
        void* requestedLoadAddress = (void*)(this->getPreferredLoadAddress() + slide);
        int protection = 0;
        if ( !this->unaccessible() ) {
                if ( this->executable() )
                        protection   |= PROT_EXEC;
                if ( this->readable() )
                        protection   |= PROT_READ;
                if ( this->writeable() )
                        protection   |= PROT_WRITE;
        }
#if __i386__
        // initially map __IMPORT segments R/W so dyld can update them
        if ( this->readOnlyImportStubs() )
                protection |= PROT_WRITE;
#endif
        // wholly zero-fill segments have nothing to mmap() in
        if ( size > 0 ) {
                void* loadAddress = mmap(requestedLoadAddress, size, protection, MAP_FIXED | MAP_PRIVATE, fd, fileOffset);
                if ( loadAddress == ((void*)(-1)) )
                        dyld::throwf("mmap() error %d at address=0x%08lX, size=0x%08lX segment=%s in Segment::map() mapping %s", errno, (uintptr_t)requestedLoadAddress, (uintptr_t)size, this->getName(), image->getPath());
        }
        // update stats
        ++ImageLoader::fgTotalSegmentsMapped;
        ImageLoader::fgTotalBytesMapped += size;
        if ( context.verboseMapping )
                dyld::log("%18s at %p->%p with permissions %c%c%c\n", this->getName(), requestedLoadAddress, (char*)requestedLoadAddress+this->getFileSize()-1,
                        (protection & PROT_READ) ? 'r' : '.',  (protection & PROT_WRITE) ? 'w' : '.',  (protection & PROT_EXEC) ? 'x' : '.' );
}

void Segment::map(const void* memoryImage, intptr_t slide, const ImageLoader* image, const ImageLoader::LinkContext& context)
{
        vm_address_t loadAddress = this->getPreferredLoadAddress() + slide;
        vm_address_t srcAddr = (uintptr_t)memoryImage + this->getFileOffset();
        vm_size_t size = this->getFileSize();
        kern_return_t r = vm_copy(mach_task_self(), srcAddr, size, loadAddress);
        if ( r != KERN_SUCCESS ) 
                throw "can't map segment";
                
        if ( context.verboseMapping )
                dyld::log("%18s at %p->%p\n", this->getName(), (char*)loadAddress, (char*)loadAddress+this->getFileSize()-1);
}

void Segment::setPermissions(const ImageLoader::LinkContext& context, const ImageLoader* image)
{
        vm_prot_t protection = 0;
        if ( !this->unaccessible() ) {
                if ( this->executable() )
                        protection   |= VM_PROT_EXECUTE;
                if ( this->readable() )
                        protection   |= VM_PROT_READ;
                if ( this->writeable() )
                        protection   |= VM_PROT_WRITE;
        }
        vm_address_t addr = this->getActualLoadAddress(image);
        vm_size_t size = this->getSize();
        const bool setCurrentPermissions = false;
        kern_return_t r = vm_protect(mach_task_self(), addr, size, setCurrentPermissions, protection);
        if ( r != KERN_SUCCESS ) 
                throw "can't set vm permissions for mapped segment";
        if ( context.verboseMapping ) {
                dyld::log("%18s at %p->%p altered permissions to %c%c%c\n", this->getName(), (char*)addr, (char*)addr+this->getFileSize()-1,
                        (protection & PROT_READ) ? 'r' : '.',  (protection & PROT_WRITE) ? 'w' : '.',  (protection & PROT_EXEC) ? 'x' : '.' );
        }
}       

void Segment::tempWritable(const ImageLoader::LinkContext& context, const ImageLoader* image)
{
        vm_address_t addr = this->getActualLoadAddress(image);
        vm_size_t size = this->getSize();
        const bool setCurrentPermissions = false;
        vm_prot_t protection = VM_PROT_WRITE | VM_PROT_READ;
        if ( this->executable() )
                protection |= VM_PROT_EXECUTE;
        kern_return_t r = vm_protect(mach_task_self(), addr, size, setCurrentPermissions, protection);
        if ( r != KERN_SUCCESS ) 
                throw "can't set vm permissions for mapped segment";
        if ( context.verboseMapping ) {
                dyld::log("%18s at %p->%p altered permissions to %c%c%c\n", this->getName(), (char*)addr, (char*)addr+this->getFileSize()-1,
                        (protection & PROT_READ) ? 'r' : '.',  (protection & PROT_WRITE) ? 'w' : '.',  (protection & PROT_EXEC) ? 'x' : '.' );
        }
}


bool Segment::hasTrailingZeroFill()
{
        return ( this->writeable() && (this->getSize() > this->getFileSize()) );
}


uintptr_t Segment::reserveAnAddressRange(size_t length, const ImageLoader::LinkContext& context)
{
        vm_address_t addr = 0;
        vm_size_t size = length;
        // in PIE programs, load initial dylibs after main executable so they don't have fixed addresses either
        if ( fgNextPIEDylibAddress != 0 ) {
                addr = fgNextPIEDylibAddress + (arc4random() & 0x3) * 4096; // add small random padding between dylibs
                kern_return_t r = vm_allocate(mach_task_self(), &addr, size, VM_FLAGS_FIXED);
                if ( r == KERN_SUCCESS ) {
                        fgNextPIEDylibAddress = addr + size;
                        return addr;
                }
                fgNextPIEDylibAddress = 0;
        }
        kern_return_t r = vm_allocate(mach_task_self(), &addr, size, VM_FLAGS_ANYWHERE);
        if ( r != KERN_SUCCESS ) 
                throw "out of address space";
        
        return addr;
}

bool Segment::reserveAddressRange(uintptr_t start, size_t length)
{
        vm_address_t addr = start;
        vm_size_t size = length;
        kern_return_t r = vm_allocate(mach_task_self(), &addr, size, false /*only this range*/);
        if ( r != KERN_SUCCESS ) 
                return false;
        return true;
}