Loading...
dyld3/Loading.cpp dyld-750.5 /dev/null
--- dyld/dyld-750.5/dyld3/Loading.cpp
+++ /dev/null
@@ -1,923 +0,0 @@
-/*
- * Copyright (c) 2017 Apple 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@
- */
-
-
-#include <bitset>
-
-#include <stdint.h>
-#include <string.h>
-#include <assert.h>
-#include <uuid/uuid.h>
-#include <mach/mach.h>
-#include <sys/stat.h> 
-#include <sys/types.h>
-#include <sys/sysctl.h>
-#include <fcntl.h>
-#include <sys/dtrace.h>
-#include <sys/errno.h>
-#include <unistd.h>
-#include <System/sys/mman.h>
-#include <System/sys/csr.h>
-#include <System/machine/cpu_capabilities.h>
-#if !TARGET_OS_SIMULATOR && !TARGET_OS_DRIVERKIT
-#include <sandbox.h>
-#include <sandbox/private.h>
-#endif
-//#include <dispatch/dispatch.h>
-#include <mach/vm_page_size.h>
-
-#include "MachOFile.h"
-#include "MachOLoaded.h"
-#include "MachOAnalyzer.h"
-#include "Logging.h"
-#include "Loading.h"
-#include "Tracing.h"
-#include "dyld2.h"
-#include "dyld_cache_format.h"
-
-#include "objc-shared-cache.h"
-
-namespace dyld {
-    void log(const char* m, ...);
-}
-
-
-namespace {
-
-// utility to track a set of ImageNum's in use
-class VIS_HIDDEN ImageNumSet
-{
-public:
-    void    add(dyld3::closure::ImageNum num);
-    bool    contains(dyld3::closure::ImageNum num) const;
-
-private:
-    std::bitset<5120>                                   _bitmap;
-    dyld3::OverflowSafeArray<dyld3::closure::ImageNum>  _overflowArray;
-};
-
-void ImageNumSet::add(dyld3::closure::ImageNum num)
-{
-    if ( num < 5120 )
-        _bitmap.set(num);
-    else
-        _overflowArray.push_back(num);
-}
-
-bool ImageNumSet::contains(dyld3::closure::ImageNum num) const
-{
-    if ( num < 5120 )
-        return _bitmap.test(num);
-
-    for (dyld3::closure::ImageNum existingNum : _overflowArray) {
-        if ( existingNum == num )
-            return true;
-    }
-    return false;
-}
-} // namespace anonymous
-
-
-namespace dyld3 {
-
-Loader::Loader(const Array<LoadedImage>& existingImages, Array<LoadedImage>& newImagesStorage,
-               const void* cacheAddress, const Array<const dyld3::closure::ImageArray*>& imagesArrays,
-               const closure::ObjCSelectorOpt* selOpt, const Array<closure::Image::ObjCSelectorImage>& selImages,
-               LogFunc logLoads, LogFunc logSegments, LogFunc logFixups, LogFunc logDofs)
-       : _existingImages(existingImages), _newImages(newImagesStorage),
-         _imagesArrays(imagesArrays), _dyldCacheAddress(cacheAddress), _dyldCacheSelectorOpt(nullptr),
-         _closureSelectorOpt(selOpt), _closureSelectorImages(selImages),
-         _logLoads(logLoads), _logSegments(logSegments), _logFixups(logFixups), _logDofs(logDofs)
-{
-#if BUILDING_DYLD
-    // This is only needed for dyld and the launch closure, not the dlopen closures
-    if ( _dyldCacheAddress != nullptr ) {
-        _dyldCacheSelectorOpt = ((const DyldSharedCache*)_dyldCacheAddress)->objcOpt()->selopt();
-    }
-#endif
-}
-
-void Loader::addImage(const LoadedImage& li)
-{
-    _newImages.push_back(li);
-}
-
-LoadedImage* Loader::findImage(closure::ImageNum targetImageNum)
-{
-#if BUILDING_DYLD
-    // The launch images are different in dyld vs libdyld.  In dyld, the new images are
-    // the launch images, while in libdyld, the existing images are the launch images
-    if (LoadedImage* info = _launchImagesCache.findImage(targetImageNum, _newImages)) {
-        return info;
-    }
-
-    for (uint64_t index = 0; index != _newImages.count(); ++index) {
-        LoadedImage& info = _newImages[index];
-        if ( info.image()->representsImageNum(targetImageNum) ) {
-            // Try cache this entry for next time
-            _launchImagesCache.tryAddImage(targetImageNum, index);
-            return &info;
-        }
-    }
-#elif BUILDING_LIBDYLD
-    for (const LoadedImage& info : _existingImages) {
-        if ( info.image()->representsImageNum(targetImageNum) )
-            return (LoadedImage*)&info;
-    }
-    for (LoadedImage& info : _newImages) {
-        if ( info.image()->representsImageNum(targetImageNum) )
-            return &info;
-    }
-#else
-#error Must be building dyld or libdyld
-#endif
-    return nullptr;
-}
-
-uintptr_t Loader::resolveTarget(closure::Image::ResolvedSymbolTarget target)
-{
-    const LoadedImage* info;
-    switch ( target.sharedCache.kind ) {
-        case closure::Image::ResolvedSymbolTarget::kindSharedCache:
-            assert(_dyldCacheAddress != nullptr);
-            return (uintptr_t)_dyldCacheAddress + (uintptr_t)target.sharedCache.offset;
-
-        case closure::Image::ResolvedSymbolTarget::kindImage:
-            info = findImage(target.image.imageNum);
-            assert(info != nullptr);
-            return (uintptr_t)(info->loadedAddress()) + (uintptr_t)target.image.offset;
-
-        case closure::Image::ResolvedSymbolTarget::kindAbsolute:
-            if ( target.absolute.value & (1ULL << 62) )
-                return (uintptr_t)(target.absolute.value | 0xC000000000000000ULL);
-            else
-                return (uintptr_t)target.absolute.value;
-   }
-    assert(0 && "malformed ResolvedSymbolTarget");
-    return 0;
-}
-
-
-void Loader::completeAllDependents(Diagnostics& diag, bool& someCacheImageOverridden)
-{
-    // accumulate all image overrides
-    STACK_ALLOC_ARRAY(ImageOverride, overrides, _existingImages.maxCount() + _newImages.maxCount());
-    for (const auto anArray : _imagesArrays) {
-        // ignore prebuilt Image* in dyld cache
-        if ( anArray->startImageNum() < dyld3::closure::kFirstLaunchClosureImageNum )
-            continue;
-        anArray->forEachImage(^(const dyld3::closure::Image* image, bool& stop) {
-            ImageOverride overrideEntry;
-            if ( image->isOverrideOfDyldCacheImage(overrideEntry.inCache) ) {
-                someCacheImageOverridden = true;
-                overrideEntry.replacement = image->imageNum();
-                overrides.push_back(overrideEntry);
-            }
-        });
-    }
-
-    // make cache for fast lookup of already loaded images
-    __block ImageNumSet alreadyLoaded;
-    for (const LoadedImage& info : _existingImages) {
-        alreadyLoaded.add(info.image()->imageNum());
-    }
-    alreadyLoaded.add(_newImages.begin()->image()->imageNum());
-
-    // for each image in _newImages, starting at the top image, make sure its dependents are in _allImages
-    uintptr_t index = 0;
-    while ( (index < _newImages.count()) && diag.noError() ) {
-        const closure::Image* image = _newImages[index].image();
-        //fprintf(stderr, "completeAllDependents(): looking at dependents of %s\n", image->path());
-        image->forEachDependentImage(^(uint32_t depIndex, closure::Image::LinkKind kind, closure::ImageNum depImageNum, bool& stop) {
-            // check if imageNum needs to be changed to an override
-            for (const ImageOverride& entry : overrides) {
-                if ( entry.inCache == depImageNum ) {
-                    depImageNum = entry.replacement;
-                    break;
-                }
-            }
-            // check if this dependent is already loaded
-            if ( !alreadyLoaded.contains(depImageNum) ) {
-                // if not, look in imagesArrays
-                const closure::Image* depImage = closure::ImageArray::findImage(_imagesArrays, depImageNum);
-                if ( depImage != nullptr ) {
-                    //dyld::log("  load imageNum=0x%05X, image path=%s\n", depImageNum, depImage->path());
-                     if ( _newImages.freeCount() == 0 ) {
-                         diag.error("too many initial images");
-                         stop = true;
-                     }
-                     else {
-                         _newImages.push_back(LoadedImage::make(depImage));
-                     }
-                    alreadyLoaded.add(depImageNum);
-                }
-                else {
-                    diag.error("unable to locate imageNum=0x%04X, depIndex=%d of %s", depImageNum, depIndex, image->path());
-                    stop = true;
-                }
-            }
-        });
-        ++index;
-    }
-}
-
-void Loader::mapAndFixupAllImages(Diagnostics& diag, bool processDOFs, bool fromOFI)
-{
-    // scan array and map images not already loaded
-    for (LoadedImage& info : _newImages) {
-        if ( info.loadedAddress() != nullptr ) {
-            // log main executable's segments
-            if ( (info.loadedAddress()->filetype == MH_EXECUTE) && (info.state() == LoadedImage::State::mapped) ) {
-                if ( _logSegments("dyld: mapped by kernel %s\n", info.image()->path()) ) {
-                    info.image()->forEachDiskSegment(^(uint32_t segIndex, uint32_t fileOffset, uint32_t fileSize, int64_t vmOffset, uint64_t vmSize, uint8_t permissions, bool laterReadOnly, bool& stop) {
-                        uint64_t start = (long)info.loadedAddress() + vmOffset;
-                        uint64_t end   = start+vmSize-1;
-                        if ( (segIndex == 0) && (permissions == 0) ) {
-                            start = 0;
-                        }
-                        _logSegments("%14s (%c%c%c) 0x%012llX->0x%012llX \n", info.loadedAddress()->segmentName(segIndex),
-                                    (permissions & PROT_READ) ? 'r' : '.', (permissions & PROT_WRITE) ? 'w' : '.', (permissions & PROT_EXEC) ? 'x' : '.' ,
-                                    start, end);
-                    });
-                }
-            }
-            // skip over ones already loaded
-            continue;
-        }
-        if ( info.image()->inDyldCache() ) {
-            if ( info.image()->overridableDylib() ) {
-                struct stat statBuf;
-                if ( stat(info.image()->path(), &statBuf) == 0 ) {
-                    // verify file has not changed since closure was built
-                    uint64_t inode;
-                    uint64_t mtime;
-                    if ( info.image()->hasFileModTimeAndInode(inode, mtime) ) {
-                        if ( (statBuf.st_mtime != mtime) || (statBuf.st_ino != inode) ) {
-                            diag.error("dylib file mtime/inode changed since closure was built for '%s'", info.image()->path());
-                        }
-                    }
-                    else {
-                        diag.error("dylib file not expected on disk, must be a root '%s'", info.image()->path());
-                    }
-                }
-                else if ( (_dyldCacheAddress != nullptr) && ((dyld_cache_header*)_dyldCacheAddress)->dylibsExpectedOnDisk ) {
-                    diag.error("dylib file missing, was in dyld shared cache '%s'", info.image()->path());
-                }
-            }
-            if ( diag.noError() ) {
-                info.setLoadedAddress((MachOLoaded*)((uintptr_t)_dyldCacheAddress + info.image()->cacheOffset()));
-                info.setState(LoadedImage::State::fixedUp);
-                if ( _logSegments("dyld: Using from dyld cache %s\n", info.image()->path()) ) {
-                    info.image()->forEachCacheSegment(^(uint32_t segIndex, uint64_t vmOffset, uint64_t vmSize, uint8_t permissions, bool &stop) {
-                        _logSegments("%14s (%c%c%c) 0x%012lX->0x%012lX \n", info.loadedAddress()->segmentName(segIndex),
-                                        (permissions & PROT_READ) ? 'r' : '.', (permissions & PROT_WRITE) ? 'w' : '.', (permissions & PROT_EXEC) ? 'x' : '.' ,
-                                        (long)info.loadedAddress()+(long)vmOffset, (long)info.loadedAddress()+(long)vmOffset+(long)vmSize-1);
-                     });
-                }
-            }
-        }
-        else {
-            mapImage(diag, info, fromOFI);
-            if ( diag.hasError() )
-                break; // out of for loop
-        }
-
-    }
-    if ( diag.hasError() )  {
-        // bummer, need to clean up by unmapping any images just mapped
-        for (LoadedImage& info : _newImages) {
-            if ( (info.state() == LoadedImage::State::mapped) && !info.image()->inDyldCache() && !info.leaveMapped() ) {
-                _logSegments("dyld: unmapping %s\n", info.image()->path());
-                unmapImage(info);
-            }
-        }
-        return;
-    }
-
-    // apply fixups
-    for (LoadedImage& info : _newImages) {
-        // images in shared cache do not need fixups applied
-        if ( info.image()->inDyldCache() )
-            continue;
-        // previously loaded images were previously fixed up
-        if ( info.state() < LoadedImage::State::fixedUp ) {
-            applyFixupsToImage(diag, info);
-            if ( diag.hasError() )
-                break;
-            info.setState(LoadedImage::State::fixedUp);
-        }
-    }
-
-    // find and register dtrace DOFs
-    if ( processDOFs ) {
-        STACK_ALLOC_OVERFLOW_SAFE_ARRAY(DOFInfo, dofImages, _newImages.count());
-        for (LoadedImage& info : _newImages) {
-            info.image()->forEachDOF(info.loadedAddress(), ^(const void* section) {
-                DOFInfo dofInfo;
-                dofInfo.dof            = section;
-                dofInfo.imageHeader    = info.loadedAddress();
-                dofInfo.imageShortName = info.image()->leafName();
-                dofImages.push_back(dofInfo);
-            });
-        }
-        registerDOFs(dofImages);
-    }
-}
-
-bool Loader::sandboxBlocked(const char* path, const char* kind)
-{
-#if TARGET_OS_SIMULATOR || TARGET_OS_DRIVERKIT
-    // sandbox calls not yet supported in dyld_sim
-    return false;
-#else
-    sandbox_filter_type filter = (sandbox_filter_type)(SANDBOX_FILTER_PATH | SANDBOX_CHECK_NO_REPORT);
-    return ( sandbox_check(getpid(), kind, filter, path) > 0 );
-#endif
-}
-
-bool Loader::sandboxBlockedMmap(const char* path)
-{
-    return sandboxBlocked(path, "file-map-executable");
-}
-
-bool Loader::sandboxBlockedOpen(const char* path)
-{
-    return sandboxBlocked(path, "file-read-data");
-}
-
-bool Loader::sandboxBlockedStat(const char* path)
-{
-    return sandboxBlocked(path, "file-read-metadata");
-}
-
-void Loader::mapImage(Diagnostics& diag, LoadedImage& info, bool fromOFI)
-{
-    dyld3::ScopedTimer timer(DBG_DYLD_TIMING_MAP_IMAGE, info.image()->path(), 0, 0);
-
-    const closure::Image*   image         = info.image();
-    uint64_t                sliceOffset   = image->sliceOffsetInFile();
-    const uint64_t          totalVMSize   = image->vmSizeToMap();
-    uint32_t                codeSignFileOffset;
-    uint32_t                codeSignFileSize;
-    bool                    isCodeSigned  = image->hasCodeSignature(codeSignFileOffset, codeSignFileSize);
-
-    // open file
-#if BUILDING_DYLD
-    int fd = dyld::my_open(info.image()->path(), O_RDONLY, 0);
-#else
-    int fd = ::open(info.image()->path(), O_RDONLY, 0);
-#endif
-    if ( fd == -1 ) {
-        int openErr = errno;
-        if ( (openErr == EPERM) && sandboxBlockedOpen(image->path()) )
-            diag.error("file system sandbox blocked open(\"%s\", O_RDONLY)", image->path());
-        else
-            diag.error("open(\"%s\", O_RDONLY) failed with errno=%d", image->path(), openErr);
-        return;
-    }
-
-    // get file info
-    struct stat statBuf;
-#if TARGET_OS_SIMULATOR
-    if ( stat(image->path(), &statBuf) != 0 ) {
-#else
-    if ( fstat(fd, &statBuf) != 0 ) {
-#endif
-        int statErr = errno;
-        if ( (statErr == EPERM) && sandboxBlockedStat(image->path()) )
-            diag.error("file system sandbox blocked stat(\"%s\")", image->path());
-        else
-            diag.error("stat(\"%s\") failed with errno=%d", image->path(), statErr);
-        close(fd);
-        return;
-    }
-
-    // verify file has not changed since closure was built
-    uint64_t inode;
-    uint64_t mtime;
-    if ( image->hasFileModTimeAndInode(inode, mtime) ) {
-        if ( (statBuf.st_mtime != mtime) || (statBuf.st_ino != inode) ) {
-            diag.error("file mtime/inode changed since closure was built for '%s'", image->path());
-            close(fd);
-            return;
-        }
-    }
-
-    // handle case on iOS where sliceOffset in closure is wrong because file was thinned after cache was built
-    if ( (_dyldCacheAddress != nullptr) && !(((dyld_cache_header*)_dyldCacheAddress)->dylibsExpectedOnDisk) ) {
-        if ( sliceOffset != 0 ) {
-            if ( round_page_kernel(codeSignFileOffset+codeSignFileSize) == round_page_kernel(statBuf.st_size) ) {
-                // file is now thin
-                sliceOffset = 0;
-            }
-        }
-    }
-
-    // register code signature
-    uint64_t coveredCodeLength  = UINT64_MAX;
-    if ( isCodeSigned ) {
-        auto sigTimer = ScopedTimer(DBG_DYLD_TIMING_ATTACH_CODESIGNATURE, 0, 0, 0);
-        fsignatures_t siginfo;
-        siginfo.fs_file_start  = sliceOffset;                           // start of mach-o slice in fat file
-        siginfo.fs_blob_start  = (void*)(long)(codeSignFileOffset);     // start of CD in mach-o file
-        siginfo.fs_blob_size   = codeSignFileSize;                      // size of CD
-        int result = fcntl(fd, F_ADDFILESIGS_RETURN, &siginfo);
-        if ( result == -1 ) {
-            int errnoCopy = errno;
-            if ( (errnoCopy == EPERM) || (errnoCopy == EBADEXEC) ) {
-                diag.error("code signature invalid (errno=%d) sliceOffset=0x%08llX, codeBlobOffset=0x%08X, codeBlobSize=0x%08X for '%s'",
-                            errnoCopy, sliceOffset, codeSignFileOffset, codeSignFileSize, image->path());
-            }
-            else {
-                diag.error("fcntl(fd, F_ADDFILESIGS_RETURN) failed with errno=%d, sliceOffset=0x%08llX, codeBlobOffset=0x%08X, codeBlobSize=0x%08X for '%s'",
-                            errnoCopy, sliceOffset, codeSignFileOffset, codeSignFileSize, image->path());
-            }
-            close(fd);
-            return;
-        }
-        coveredCodeLength = siginfo.fs_file_start;
-        if ( coveredCodeLength < codeSignFileOffset ) {
-            diag.error("code signature does not cover entire file up to signature");
-            close(fd);
-            return;
-        }
-    }
-
-    // <rdar://problem/41015217> dyld should use F_CHECK_LV even on unsigned binaries
-    {
-        // <rdar://problem/32684903> always call F_CHECK_LV to preflight
-        fchecklv checkInfo;
-        char  messageBuffer[512];
-        messageBuffer[0] = '\0';
-        checkInfo.lv_file_start = sliceOffset;
-        checkInfo.lv_error_message_size = sizeof(messageBuffer);
-        checkInfo.lv_error_message = messageBuffer;
-        int res = fcntl(fd, F_CHECK_LV, &checkInfo);
-        if ( res == -1 ) {
-             diag.error("code signature in (%s) not valid for use in process: %s", image->path(), messageBuffer);
-             close(fd);
-             return;
-        }
-    }
-
-    // reserve address range
-    vm_address_t loadAddress = 0;
-    kern_return_t r = vm_allocate(mach_task_self(), &loadAddress, (vm_size_t)totalVMSize, VM_FLAGS_ANYWHERE);
-    if ( r != KERN_SUCCESS ) {
-        diag.error("vm_allocate(size=0x%0llX) failed with result=%d", totalVMSize, r);
-        close(fd);
-        return;
-    }
-
-    if ( sliceOffset != 0 )
-        _logSegments("dyld: Mapping %s (slice offset=%llu)\n", image->path(), sliceOffset);
-    else
-        _logSegments("dyld: Mapping %s\n", image->path());
-
-    // map each segment
-    __block bool           mmapFailure = false;
-    __block const uint8_t* codeSignatureStartAddress = nullptr;
-    __block const uint8_t* linkeditEndAddress = nullptr;
-    __block bool           mappedFirstSegment = false;
-    __block uint64_t       maxFileOffset = 0;
-    image->forEachDiskSegment(^(uint32_t segIndex, uint32_t fileOffset, uint32_t fileSize, int64_t vmOffset, uint64_t vmSize, uint8_t permissions, bool laterReadOnly, bool& stop) {
-        // <rdar://problem/32363581> Mapping zero filled segments fails with mmap of size 0
-        if ( fileSize == 0 )
-            return;
-        void* segAddress = mmap((void*)(loadAddress+vmOffset), fileSize, permissions, MAP_FIXED | MAP_PRIVATE, fd, sliceOffset+fileOffset);
-        int mmapErr = errno;
-        if ( segAddress == MAP_FAILED ) {
-            if ( mmapErr == EPERM ) {
-                if ( sandboxBlockedMmap(image->path()) )
-                    diag.error("file system sandbox blocked mmap() of '%s'", image->path());
-                else
-                    diag.error("code signing blocked mmap() of '%s'", image->path());
-            }
-            else {
-                diag.error("mmap(addr=0x%0llX, size=0x%08X) failed with errno=%d for %s", loadAddress+vmOffset, fileSize, mmapErr, image->path());
-            }
-            mmapFailure = true;
-            stop = true;
-        }
-        else if ( codeSignFileOffset > fileOffset ) {
-            codeSignatureStartAddress = (uint8_t*)segAddress + (codeSignFileOffset-fileOffset);
-            linkeditEndAddress = (uint8_t*)segAddress + vmSize;
-        }
-        // sanity check first segment is mach-o header
-        if ( (segAddress != MAP_FAILED) && !mappedFirstSegment ) {
-            mappedFirstSegment = true;
-            const MachOFile* mf = (MachOFile*)segAddress;
-            if ( !mf->isMachO(diag, fileSize) ) {
-                mmapFailure = true;
-                stop = true;
-            }
-        }
-        if ( !mmapFailure ) {
-            const MachOLoaded* lmo = (MachOLoaded*)loadAddress;
-            _logSegments("%14s (%c%c%c) 0x%012lX->0x%012lX \n", lmo->segmentName(segIndex),
-                         (permissions & PROT_READ) ? 'r' : '.', (permissions & PROT_WRITE) ? 'w' : '.', (permissions & PROT_EXEC) ? 'x' : '.' ,
-                         (long)segAddress, (long)segAddress+(long)vmSize-1);
-        }
-        maxFileOffset = fileOffset + fileSize;
-    });
-    if ( mmapFailure ) {
-        ::vm_deallocate(mach_task_self(), loadAddress, (vm_size_t)totalVMSize);
-        ::close(fd);
-        return;
-    }
-
-    // <rdar://problem/47163421> speculatively read whole slice
-    fspecread_t specread = {} ;
-    specread.fsr_offset = sliceOffset;
-    specread.fsr_length = maxFileOffset;
-    specread.fsr_flags  = 0;
-    fcntl(fd, F_SPECULATIVE_READ, &specread);
-    _logSegments("dyld: Speculatively read offset=0x%08llX, len=0x%08llX, path=%s\n", sliceOffset, maxFileOffset, image->path());
-
-    // close file
-    close(fd);
-
-#if BUILDING_LIBDYLD
-    // verify file has not changed since closure was built by checking code signature has not changed
-    struct CDHashWrapper {
-        uint8_t cdHash[20];
-    };
-
-    // Get all the hashes for the image
-    STACK_ALLOC_OVERFLOW_SAFE_ARRAY(CDHashWrapper, expectedCDHashes, 1);
-    image->forEachCDHash(^(const uint8_t *cdHash, bool &stop) {
-        CDHashWrapper cdHashWrapper;
-        memcpy(cdHashWrapper.cdHash, cdHash, sizeof(CDHashWrapper::cdHash));
-        expectedCDHashes.push_back(cdHashWrapper);
-    });
-
-    if (!expectedCDHashes.empty()) {
-        if (expectedCDHashes.count() != 1) {
-            // We should only see a single hash for dylibs
-            diag.error("code signature count invalid");
-        } else if ( codeSignatureStartAddress == nullptr ) {
-            diag.error("code signature missing");
-        }
-        else if ( codeSignatureStartAddress+codeSignFileSize > linkeditEndAddress ) {
-            diag.error("code signature extends beyond end of __LINKEDIT");
-        }
-        else {
-            // Get all the cd hashes for the macho
-            STACK_ALLOC_OVERFLOW_SAFE_ARRAY(CDHashWrapper, foundCDHashes, 1);
-            const MachOLoaded* lmo = (MachOLoaded*)loadAddress;
-            lmo->forEachCDHashOfCodeSignature(codeSignatureStartAddress, codeSignFileSize,
-                                              ^(const uint8_t *cdHash) {
-                CDHashWrapper cdHashWrapper;
-                memcpy(cdHashWrapper.cdHash, cdHash, sizeof(CDHashWrapper::cdHash));
-                foundCDHashes.push_back(cdHashWrapper);
-            });
-
-            if (foundCDHashes.empty()) {
-                diag.error("code signature format invalid");
-            } else if (expectedCDHashes.count() != foundCDHashes.count()) {
-                diag.error("code signature count invalid");
-            } else {
-                // We found a hash, so make sure its equal.
-                if ( ::memcmp(foundCDHashes[0].cdHash, expectedCDHashes[0].cdHash, 20) != 0 )
-                    diag.error("code signature changed since closure was built");
-            }
-        }
-        if ( diag.hasError() ) {
-            ::vm_deallocate(mach_task_self(), loadAddress, (vm_size_t)totalVMSize);
-            return;
-        }
-    }
-
-#endif
-
-#if __IPHONE_OS_VERSION_MIN_REQUIRED && !TARGET_OS_SIMULATOR
-    // tell kernel about fairplay encrypted regions
-    uint32_t fpTextOffset;
-    uint32_t fpSize;
-    if ( image->isFairPlayEncrypted(fpTextOffset, fpSize) ) {
-        const mach_header* mh = (mach_header*)loadAddress;
-        int result = ::mremap_encrypted(((uint8_t*)mh) + fpTextOffset, fpSize, 1, mh->cputype, mh->cpusubtype);
-        if ( result != 0 ) {
-            diag.error("could not register fairplay decryption, mremap_encrypted() => %d", result);
-            ::vm_deallocate(mach_task_self(), loadAddress, (vm_size_t)totalVMSize);
-            return;
-        }
-    }
-#endif
-
-    _logLoads("dyld: load %s\n", image->path());
-
-    timer.setData4((uint64_t)loadAddress);
-    info.setLoadedAddress((MachOLoaded*)loadAddress);
-    info.setState(LoadedImage::State::mapped);
-}
-
-void Loader::unmapImage(LoadedImage& info)
-{
-    assert(info.loadedAddress() != nullptr);
-    ::vm_deallocate(mach_task_self(), (vm_address_t)info.loadedAddress(), (vm_size_t)(info.image()->vmSizeToMap()));
-    info.setLoadedAddress(nullptr);
-}
-
-void Loader::registerDOFs(const Array<DOFInfo>& dofs)
-{
-    if ( dofs.empty() )
-        return;
-
-    int fd = open("/dev/" DTRACEMNR_HELPER, O_RDWR);
-    if ( fd < 0 ) {
-        _logDofs("can't open /dev/" DTRACEMNR_HELPER " to register dtrace DOF sections\n");
-    }
-    else {
-        // allocate a buffer on the stack for the variable length dof_ioctl_data_t type
-        uint8_t buffer[sizeof(dof_ioctl_data_t) + dofs.count()*sizeof(dof_helper_t)];
-        dof_ioctl_data_t* ioctlData = (dof_ioctl_data_t*)buffer;
-
-        // fill in buffer with one dof_helper_t per DOF section
-        ioctlData->dofiod_count = dofs.count();
-        for (unsigned int i=0; i < dofs.count(); ++i) {
-            strlcpy(ioctlData->dofiod_helpers[i].dofhp_mod, dofs[i].imageShortName, DTRACE_MODNAMELEN);
-            ioctlData->dofiod_helpers[i].dofhp_dof = (uintptr_t)(dofs[i].dof);
-            ioctlData->dofiod_helpers[i].dofhp_addr = (uintptr_t)(dofs[i].dof);
-        }
-
-        // tell kernel about all DOF sections en mas
-        // pass pointer to ioctlData because ioctl() only copies a fixed size amount of data into kernel
-        user_addr_t val = (user_addr_t)(unsigned long)ioctlData;
-        if ( ioctl(fd, DTRACEHIOC_ADDDOF, &val) != -1 ) {
-            // kernel returns a unique identifier for each section in the dofiod_helpers[].dofhp_dof field.
-            // Note, the closure marked the image as being never unload, so we don't need to keep the ID around
-            // or support unregistering it later.
-            for (unsigned int i=0; i < dofs.count(); ++i) {
-                _logDofs("dyld: registering DOF section %p in %s with dtrace, ID=0x%08X\n",
-                         dofs[i].dof, dofs[i].imageShortName, (int)(ioctlData->dofiod_helpers[i].dofhp_dof));
-            }
-        }
-        else {
-            _logDofs("dyld: ioctl to register dtrace DOF section failed\n");
-        }
-        close(fd);
-    }
-}
-
-bool Loader::dtraceUserProbesEnabled()
-{
-    uint8_t dofEnabled = *((uint8_t*)_COMM_PAGE_DTRACE_DOF_ENABLED);
-    return ( (dofEnabled & 1) );
-}
-
-
-void Loader::vmAccountingSetSuspended(bool suspend, LogFunc logger)
-{
-#if __arm__ || __arm64__
-    // <rdar://problem/29099600> dyld should tell the kernel when it is doing fix-ups caused by roots
-    logger("vm.footprint_suspend=%d\n", suspend);
-    int newValue = suspend ? 1 : 0;
-    int oldValue = 0;
-    size_t newlen = sizeof(newValue);
-    size_t oldlen = sizeof(oldValue);
-    sysctlbyname("vm.footprint_suspend", &oldValue, &oldlen, &newValue, newlen);
-#endif
-}
-
-void Loader::applyFixupsToImage(Diagnostics& diag, LoadedImage& info)
-{
-    dyld3::ScopedTimer timer(DBG_DYLD_TIMING_APPLY_FIXUPS, (uint64_t)info.loadedAddress(), 0, 0);
-    closure::ImageNum       cacheImageNum;
-    const char*             leafName         = info.image()->leafName();
-    const closure::Image*   image            = info.image();
-    const uint8_t*          imageLoadAddress = (uint8_t*)info.loadedAddress();
-    uintptr_t               slide            = info.loadedAddress()->getSlide();
-    bool                    overrideOfCache  = info.image()->isOverrideOfDyldCacheImage(cacheImageNum);
-    
-    if ( overrideOfCache )
-        vmAccountingSetSuspended(true, _logFixups);
-    image->forEachFixup(^(uint64_t imageOffsetToRebase, bool& stop) {
-        // this is a rebase, add slide
-        uintptr_t* fixUpLoc = (uintptr_t*)(imageLoadAddress + imageOffsetToRebase);
-        *fixUpLoc += slide;
-        _logFixups("dyld: fixup: %s:%p += %p\n", leafName, fixUpLoc, (void*)slide);
-    },
-    ^(uint64_t imageOffsetToBind, closure::Image::ResolvedSymbolTarget bindTarget, bool& stop) {
-        // this is a bind, set to target
-        uintptr_t* fixUpLoc = (uintptr_t*)(imageLoadAddress + imageOffsetToBind);
-        uintptr_t value = resolveTarget(bindTarget);
-        _logFixups("dyld: fixup: %s:%p = %p\n", leafName, fixUpLoc, (void*)value);
-        *fixUpLoc = value;
-    },
-    ^(uint64_t imageOffsetToStartsInfo, const Array<closure::Image::ResolvedSymbolTarget>& targets, bool& stop) {
-        // this is a chain of fixups, fix up all
-        STACK_ALLOC_OVERFLOW_SAFE_ARRAY(const void*, targetAddrs, 128);
-        targetAddrs.reserve(targets.count());
-        for (uint32_t i=0; i < targets.count(); ++i)
-            targetAddrs.push_back((void*)resolveTarget(targets[i]));
-        ((dyld3::MachOAnalyzer*)(info.loadedAddress()))->withChainStarts(diag, imageOffsetToStartsInfo, ^(const dyld_chained_starts_in_image* starts) {
-            info.loadedAddress()->fixupAllChainedFixups(diag, starts, slide, targetAddrs, ^(void* loc, void* newValue) {
-                _logFixups("dyld: fixup: %s:%p = %p\n", leafName, loc, newValue);
-            });
-        });
-    },
-    ^(uint64_t imageOffsetToFixup) {
-        uintptr_t* fixUpLoc = (uintptr_t*)(imageLoadAddress + imageOffsetToFixup);
-        _logFixups("dyld: fixup objc image info: %s Setting objc image info for precomputed objc\n", leafName);
-
-        MachOAnalyzer::ObjCImageInfo *imageInfo = (MachOAnalyzer::ObjCImageInfo *)fixUpLoc;
-        ((MachOAnalyzer::ObjCImageInfo *)imageInfo)->flags |= MachOAnalyzer::ObjCImageInfo::dyldPreoptimized;
-    },
-    ^(uint64_t imageOffsetToBind, closure::Image::ResolvedSymbolTarget bindTarget, bool& stop) {
-        // this is a bind, set to target
-        uintptr_t* fixUpLoc = (uintptr_t*)(imageLoadAddress + imageOffsetToBind);
-        uintptr_t value = resolveTarget(bindTarget);
-        _logFixups("dyld: fixup objc protocol: %s:%p = %p\n", leafName, fixUpLoc, (void*)value);
-        *fixUpLoc = value;
-    },
-    ^(uint64_t imageOffsetToFixup, uint32_t selectorIndex, bool inSharedCache, bool &stop) {
-        // fixupObjCSelRefs
-        closure::Image::ResolvedSymbolTarget fixupTarget;
-        if ( inSharedCache ) {
-            const char* selectorString = _dyldCacheSelectorOpt->getEntryForIndex(selectorIndex);
-            fixupTarget.sharedCache.kind     = closure::Image::ResolvedSymbolTarget::kindSharedCache;
-            fixupTarget.sharedCache.offset   = (uint64_t)selectorString - (uint64_t)_dyldCacheAddress;
-        } else {
-            closure::ImageNum imageNum;
-            uint64_t vmOffset;
-            bool gotLocation = _closureSelectorOpt->getStringLocation(selectorIndex, _closureSelectorImages, imageNum, vmOffset);
-            assert(gotLocation);
-            fixupTarget.image.kind = closure::Image::ResolvedSymbolTarget::kindImage;
-            fixupTarget.image.imageNum = imageNum;
-            fixupTarget.image.offset = vmOffset;
-        }
-
-        uintptr_t* fixUpLoc = (uintptr_t*)(imageLoadAddress + imageOffsetToFixup);
-        uintptr_t value = resolveTarget(fixupTarget);
-        _logFixups("dyld: fixup objc selector: %s:%p(was '%s') = %p(now '%s')\n", leafName, fixUpLoc, (const char*)*fixUpLoc, (void*)value, (const char*)value);
-        *fixUpLoc = value;
-    }, ^(uint64_t imageOffsetToFixup, bool &stop) {
-        // fixupObjCStableSwift
-        // Class really is stable Swift, pretending to be pre-stable.
-        // Fix its lie.
-        uintptr_t* fixUpLoc = (uintptr_t*)(imageLoadAddress + imageOffsetToFixup);
-        uintptr_t value = ((*fixUpLoc) | MachOAnalyzer::ObjCClassInfo::FAST_IS_SWIFT_STABLE) & ~MachOAnalyzer::ObjCClassInfo::FAST_IS_SWIFT_LEGACY;
-        _logFixups("dyld: fixup objc stable Swift: %s:%p = %p\n", leafName, fixUpLoc, (void*)value);
-        *fixUpLoc = value;
-    }, ^(uint64_t imageOffsetToFixup, bool &stop) {
-        // TODO: Implement this
-    });
-
-#if __i386__
-    __block bool segmentsMadeWritable = false;
-    image->forEachTextReloc(^(uint32_t imageOffsetToRebase, bool& stop) {
-        if ( !segmentsMadeWritable )
-            setSegmentProtects(info, true);
-        uintptr_t* fixUpLoc = (uintptr_t*)(imageLoadAddress + imageOffsetToRebase);
-        *fixUpLoc += slide;
-        _logFixups("dyld: fixup: %s:%p += %p\n", leafName, fixUpLoc, (void*)slide);
-     },
-    ^(uint32_t imageOffsetToBind, closure::Image::ResolvedSymbolTarget bindTarget, bool& stop) {
-        // FIXME
-    });
-    if ( segmentsMadeWritable )
-        setSegmentProtects(info, false);
-#endif
-
-    // make any read-only data segments read-only
-    if ( image->hasReadOnlyData() && !image->inDyldCache() ) {
-        image->forEachDiskSegment(^(uint32_t segIndex, uint32_t fileOffset, uint32_t fileSize, int64_t vmOffset, uint64_t vmSize, uint8_t permissions, bool laterReadOnly, bool& segStop) {
-            if ( laterReadOnly ) {
-                ::mprotect((void*)(imageLoadAddress+vmOffset), (size_t)vmSize, VM_PROT_READ);
-            }
-        });
-    }
-
-    if ( overrideOfCache )
-        vmAccountingSetSuspended(false, _logFixups);
-}
-
-#if __i386__
-void Loader::setSegmentProtects(const LoadedImage& info, bool write)
-{
-    info.image()->forEachDiskSegment(^(uint32_t segIndex, uint32_t fileOffset, uint32_t fileSize, int64_t vmOffset, uint64_t vmSize, uint8_t protections, bool laterReadOnly, bool& segStop) {
-        if ( protections & VM_PROT_WRITE )
-            return;
-        uint32_t regionProt = protections;
-        if ( write )
-            regionProt = VM_PROT_WRITE | VM_PROT_READ;
-        kern_return_t r = vm_protect(mach_task_self(), ((uintptr_t)info.loadedAddress())+(uintptr_t)vmOffset, (uintptr_t)vmSize, false, regionProt);
-        assert( r == KERN_SUCCESS );
-    });
-}
-#endif
-
-#if BUILDING_DYLD
-LoadedImage* Loader::LaunchImagesCache::findImage(closure::ImageNum imageNum,
-                                                  Array<LoadedImage>& images) const {
-    if ( (imageNum < _firstImageNum) || (imageNum >= _lastImageNum) )
-        return nullptr;
-
-    uint64_t cacheIndex = imageNum - _firstImageNum;
-    uint32_t imagesIndex = _imageIndices[cacheIndex];
-    if ( imagesIndex == 0 )
-        return nullptr;
-
-    // Note the index is offset by 1 so that 0's are not yet set
-    return &images[imagesIndex - 1];
-}
-
-void Loader::LaunchImagesCache::tryAddImage(closure::ImageNum imageNum,
-                                            uint64_t allImagesIndex) {
-    if ( (imageNum < _firstImageNum) || (imageNum >= _lastImageNum) )
-        return;
-
-    uint64_t cacheIndex = imageNum - _firstImageNum;
-
-    // Note the index is offset by 1 so that 0's are not yet set
-    _imageIndices[cacheIndex] = (uint32_t)allImagesIndex + 1;
-}
-
-void forEachLineInFile(const char* buffer, size_t bufferLen, void (^lineHandler)(const char* line, bool& stop))
-{
-    bool stop = false;
-    const char* const eof = &buffer[bufferLen];
-    for (const char* s = buffer; s < eof; ++s) {
-        char lineBuffer[MAXPATHLEN];
-        char* t = lineBuffer;
-        char* tEnd = &lineBuffer[MAXPATHLEN];
-        while ( (s < eof) && (t != tEnd) ) {
-            if ( *s == '\n' )
-            break;
-            *t++ = *s++;
-        }
-        *t = '\0';
-        lineHandler(lineBuffer, stop);
-        if ( stop )
-        break;
-    }
-}
-
-void forEachLineInFile(const char* path, void (^lineHandler)(const char* line, bool& stop))
-{
-    int fd = dyld::my_open(path, O_RDONLY, 0);
-    if ( fd != -1 ) {
-        struct stat statBuf;
-        if ( fstat(fd, &statBuf) == 0 ) {
-            const char* lines = (const char*)mmap(nullptr, (size_t)statBuf.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
-            if ( lines != MAP_FAILED ) {
-                forEachLineInFile(lines, (size_t)statBuf.st_size, lineHandler);
-                munmap((void*)lines, (size_t)statBuf.st_size);
-            }
-        }
-        close(fd);
-    }
-}
-
-#endif
-
-#if (BUILDING_LIBDYLD || BUILDING_DYLD)
-    bool internalInstall()
-    {
-#if TARGET_OS_SIMULATOR
-        return false;
-#elif __IPHONE_OS_VERSION_MIN_REQUIRED
-        uint32_t devFlags = *((uint32_t*)_COMM_PAGE_DEV_FIRM);
-        return ( (devFlags & 1) == 1 );
-#else
-        return ( csr_check(CSR_ALLOW_APPLE_INTERNAL) == 0 );
-#endif
-    }
-#endif
-
-#if BUILDING_LIBDYLD
-// hack because libdyld.dylib should not link with libc++.dylib
-extern "C" void __cxa_pure_virtual() __attribute__((visibility("hidden")));
-void __cxa_pure_virtual()
-{
-    abort();
-}
-#endif
-
-} // namespace dyld3
-
-
-
-
-