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mach_o_writer/HeaderWriter.cpp dyld-1340 /dev/null
--- dyld/dyld-1340/mach_o_writer/HeaderWriter.cpp
+++ /dev/null
@@ -1,1065 +0,0 @@
-/*
- * Copyright (c) 2021 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 <utility>
-
-#include <stdlib.h>
-#include <assert.h>
-#include <string.h>
-#include <assert.h>
-
-#include <TargetConditionals.h>
-#if !TARGET_OS_EXCLAVEKIT
-  #include <unistd.h>
-#endif
-
-#include <mach-o/fixup-chains.h>
-
-// mach_o
-#include "Array.h"
-#include "Architecture.h"
-#include "Misc.h"
-#include "Policy.h"
-#include "LoggingStub.h"
-#include "Version32.h"
-
-// mach_o_writer
-#include "HeaderWriter.h"
-
-#if TARGET_OS_EXCLAVEKIT
-#ifndef VM_PROT_READ
-    #define VM_PROT_READ    1
-#endif
-
-#ifndef VM_PROT_WRITE
-    #define VM_PROT_WRITE   2
-#endif
-
-#ifndef VM_PROT_EXECUTE
-    #define VM_PROT_EXECUTE 4
-#endif
-#endif // TARGET_OS_EXCLAVEKIT
-
-using mach_o::Architecture;
-using mach_o::Platform;
-using mach_o::PlatformAndVersions;
-using mach_o::Policy;
-using mach_o::Version32;
-
-namespace mach_o {
-
-//
-// MARK: --- methods that create and modify ---
-//
-
-HeaderWriter* HeaderWriter::make(std::span<uint8_t> buffer, uint32_t filetype, uint32_t flags, Architecture arch, bool addImplicitTextSegment)
-{
-    const size_t minHeaderAlignment = filetype == MH_OBJECT ? 8 : getpagesize();
-    assert(((uint64_t)buffer.data() & (minHeaderAlignment - 1)) == 0);
-    assert(buffer.size() >= sizeof(mach_header_64));
-    bzero(buffer.data(), buffer.size());
-    HeaderWriter& header = *(HeaderWriter*)buffer.data();
-    mach_header& mh = header.mh;
-    if ( arch.isBigEndian() ) {
-        mh.magic      = arch.is64() ? MH_CIGAM_64 : MH_CIGAM;
-        mh.filetype   = OSSwapBigToHostInt32(filetype);
-        mh.ncmds      = 0;
-        mh.sizeofcmds = OSSwapBigToHostInt32(MH_NOUNDEFS | MH_DYLDLINK | MH_TWOLEVEL);
-        mh.flags      = OSSwapBigToHostInt32(flags);
-        arch.set(mh);
-        return &header; // can only construct mach_header for big-endian
-    }
-    else {
-        mh.magic      = arch.is64() ? MH_MAGIC_64 : MH_MAGIC;
-        mh.filetype   = filetype;
-        mh.ncmds      = 0;
-        mh.sizeofcmds = 0;
-        mh.flags      = flags;
-        arch.set(mh);
-    }
-    if ( addImplicitTextSegment && (filetype != MH_OBJECT) ) {
-        SegmentInfo segInfo { .segmentName="__TEXT", .vmaddr=0, .vmsize=0x1000, .fileOffset=0, .fileSize=0x1000, .maxProt=(VM_PROT_READ | VM_PROT_EXECUTE), .initProt=(VM_PROT_READ | VM_PROT_EXECUTE) };
-        header.addSegment(segInfo, std::array { "__text" });
-    }
-
-    return &header;
-}
-
-void HeaderWriter::save(char savedPath[PATH_MAX]) const
-{
-    ::strcpy(savedPath, "/tmp/mocko-XXXXXX");
-    int fd = ::mkstemp(savedPath);
-    if ( fd != -1 ) {
-        size_t size = sizeof(mach_header_64) + mh.sizeofcmds;
-        ::pwrite(fd, this, size, 0);
-        ::close(fd);
-    }
-}
-
-load_command* HeaderWriter::firstLoadCommand()
-{
-    if ( mh.magic == MH_MAGIC )
-        return (load_command*)((uint8_t*)this + sizeof(mach_header));
-    else
-        return (load_command*)((uint8_t*)this + sizeof(mach_header_64));
-}
-
-// creates space for a new load command, but does not fill in its payload
-load_command* HeaderWriter::appendLoadCommand(uint32_t cmd, uint32_t cmdSize)
-{
-    load_command* thisCmd = (load_command*)((uint8_t*)firstLoadCommand() + mh.sizeofcmds);
-    thisCmd->cmd          = cmd;
-    thisCmd->cmdsize      = cmdSize;
-    mh.ncmds += 1;
-    mh.sizeofcmds += cmdSize;
-
-    return thisCmd;
-}
-
-// copies a new load command from another
-void HeaderWriter::appendLoadCommand(const load_command* lc)
-{
-    load_command* thisCmd = (load_command*)((uint8_t*)firstLoadCommand() + mh.sizeofcmds);
-    ::memcpy(thisCmd, lc, lc->cmdsize);
-    mh.ncmds += 1;
-    mh.sizeofcmds += lc->cmdsize;
-}
-
-void HeaderWriter::addBuildVersion(Platform platform, Version32 minOS, Version32 sdk, std::span<const build_tool_version> tools)
-{
-    assert(platform != Platform::zippered && "can't add a build command for Platform::zippered, it must be split");
-    uint32_t               lcSize = (uint32_t)(sizeof(build_version_command) + tools.size() * sizeof(build_tool_version));
-    build_version_command* bv     = (build_version_command*)appendLoadCommand(LC_BUILD_VERSION, lcSize);
-    bv->platform = platform.value();
-    bv->minos    = minOS.value();
-    bv->sdk      = sdk.value();
-    bv->ntools   = (uint32_t)tools.size();
-    if ( bv->ntools != 0 )
-        memcpy((uint8_t*)bv + sizeof(build_version_command), &tools[0], tools.size() * sizeof(build_tool_version));
-}
-
-void HeaderWriter::addMinVersion(Platform platform, Version32 minOS, Version32 sdk)
-{
-    version_min_command vc;
-    vc.cmdsize = sizeof(version_min_command);
-    vc.version = minOS.value();
-    vc.sdk     = sdk.value();
-    if ( platform == Platform::macOS )
-        vc.cmd = LC_VERSION_MIN_MACOSX;
-    else if ( (platform == Platform::iOS) || (platform == Platform::iOS_simulator) )
-        vc.cmd = LC_VERSION_MIN_IPHONEOS;
-    else if ( (platform == Platform::watchOS) || (platform == Platform::watchOS_simulator) )
-        vc.cmd = LC_VERSION_MIN_WATCHOS;
-    else if ( (platform == Platform::tvOS) || (platform == Platform::tvOS_simulator) )
-        vc.cmd = LC_VERSION_MIN_TVOS;
-    else
-        assert(0 && "unknown platform");
-    appendLoadCommand((load_command*)&vc);
-}
-
-void HeaderWriter::setHasThreadLocalVariables()
-{
-    assert(mh.filetype != MH_OBJECT);
-    mh.flags |= MH_HAS_TLV_DESCRIPTORS;
-}
-
-void HeaderWriter::setHasWeakDefs()
-{
-    assert(mh.filetype != MH_OBJECT);
-    mh.flags |= MH_WEAK_DEFINES;
-}
-
-void HeaderWriter::setUsesWeakDefs()
-{
-    assert(mh.filetype != MH_OBJECT);
-    mh.flags |= MH_BINDS_TO_WEAK;
-}
-
-void HeaderWriter::setAppExtensionSafe()
-{
-    assert(mh.filetype == MH_DYLIB || mh.filetype == MH_DYLIB_STUB);
-    mh.flags |= MH_APP_EXTENSION_SAFE;
-}
-
-void HeaderWriter::setSimSupport()
-{
-    assert(mh.filetype == MH_DYLIB || mh.filetype == MH_DYLIB_STUB);
-    mh.flags |= MH_SIM_SUPPORT;
-}
-
-void HeaderWriter::setNoReExportedDylibs()
-{
-    assert(mh.filetype == MH_DYLIB || mh.filetype == MH_DYLIB_STUB);
-    mh.flags |= MH_NO_REEXPORTED_DYLIBS;
-}
-
-void HeaderWriter::setNoDynamicAccess()
-{
-    assert(mh.filetype == MH_DYLIB || mh.filetype == MH_DYLIB_STUB || mh.filetype == MH_EXECUTE);
-    mh.flags |= MH_NO_DYNAMIC_ACCESS;
-}
-
-void HeaderWriter::addPlatformInfo(Platform platform, Version32 minOS, Version32 sdk, std::span<const build_tool_version> tools)
-{
-    Architecture arch(&mh);
-    Policy policy(arch, { platform, minOS, sdk }, mh.filetype);
-    switch ( policy.useBuildVersionLoadCommand() ) {
-        case Policy::preferUse:
-        case Policy::mustUse:
-            // three macOS dylibs under libSystem need to be built with old load commands to support old simulator runtimes
-            if ( isSimSupport() && (platform == Platform::macOS) && ((arch == Architecture::x86_64) || (arch == Architecture::i386)) )
-                addMinVersion(platform, minOS, sdk);
-            else
-                addBuildVersion(platform, minOS, sdk, tools);
-            break;
-        case Policy::preferDontUse:
-        case Policy::mustNotUse:
-            addMinVersion(platform, minOS, sdk);
-            break;
-    }
-}
-
-void HeaderWriter::addNullUUID()
-{
-    uuid_command uc;
-    uc.cmd     = LC_UUID;
-    uc.cmdsize = sizeof(uuid_command);
-    bzero(uc.uuid, 16);
-    appendLoadCommand((load_command*)&uc);
-}
-
-void HeaderWriter::addUniqueUUID(uuid_t copyOfUUID)
-{
-    uuid_command uc;
-    uc.cmd     = LC_UUID;
-    uc.cmdsize = sizeof(uuid_command);
-    uuid_generate_random(uc.uuid);
-    appendLoadCommand((load_command*)&uc);
-    if ( copyOfUUID )
-        memcpy(copyOfUUID, uc.uuid, sizeof(uuid_t));
-}
-
-void HeaderWriter::updateUUID(uuid_t uuid)
-{
-    __block bool found = false;
-    forEachLoadCommandSafe(^(const load_command *cmd, bool &stop) {
-        if ( cmd->cmd == LC_UUID ) {
-            memcpy(((uuid_command*)cmd)->uuid, uuid, 16);
-            found = true;
-            stop = true;
-        }
-    });
-    assert(found && "updateUUID called without a LC_UUID command");
-}
-
-void HeaderWriter::addSegment(const SegmentInfo& info, std::span<const char* const> sectionNames)
-{
-    if ( is64() ) {
-        uint32_t            lcSize = (uint32_t)(sizeof(segment_command_64) + sectionNames.size() * sizeof(section_64));
-        segment_command_64* sc     = (segment_command_64*)appendLoadCommand(LC_SEGMENT_64, lcSize);
-        strncpy(sc->segname, info.segmentName.begin(), 16);
-        sc->vmaddr             = info.vmaddr;
-        sc->vmsize             = info.vmsize;
-        sc->fileoff            = info.fileOffset;
-        sc->filesize           = info.fileSize;
-        sc->maxprot            = info.maxProt;
-        sc->initprot           = info.initProt;
-        sc->nsects             = (uint32_t)sectionNames.size();
-        sc->flags              = info.flags;
-        section_64* const sect = (section_64*)((uint8_t*)sc + sizeof(struct segment_command_64));
-        uint32_t sectionIndex  = 0;
-        for ( const char* sectName : sectionNames ) {
-            strncpy(sect[sectionIndex].segname, info.segmentName.begin(), 16);
-            strncpy(sect[sectionIndex].sectname, sectName, 16);
-            ++sectionIndex;
-        }
-    }
-    else {
-        uint32_t         lcSize = (uint32_t)(sizeof(segment_command) + sectionNames.size() * sizeof(section));
-        segment_command* sc     = (segment_command*)appendLoadCommand(LC_SEGMENT, lcSize);
-        strncpy(sc->segname, info.segmentName.begin(), 16);
-        sc->vmaddr             = (uint32_t)info.vmaddr;
-        sc->vmsize             = (uint32_t)info.vmsize;
-        sc->fileoff            = info.fileOffset;
-        sc->filesize           = info.fileSize;
-        sc->maxprot            = info.maxProt;
-        sc->initprot           = info.initProt;
-        sc->nsects             = (uint32_t)sectionNames.size();
-        sc->flags              = info.flags;
-        section* const sect = (section*)((uint8_t*)sc + sizeof(struct segment_command));
-        uint32_t sectionIndex  = 0;
-        for ( const char* sectName : sectionNames ) {
-            strncpy(sect[sectionIndex].segname, info.segmentName.begin(), 16);
-            strncpy(sect[sectionIndex].sectname, sectName, 16);
-            ++sectionIndex;
-        }
-    }
-}
-
-void HeaderWriter::updateSection(const SectionInfo& info)
-{
-    forEachLoadCommandSafe(^(const load_command* cmd, bool& stop) {
-        if ( cmd->cmd == LC_SEGMENT_64 ) {
-            segment_command_64* segCmd = (segment_command_64*)cmd;
-            if (info.segmentName == segCmd->segname) {
-                section_64* const  sectionsStart = (section_64*)((char*)segCmd + sizeof(struct segment_command_64));
-                section_64* const  sectionsEnd   = &sectionsStart[segCmd->nsects];
-                for ( section_64* sect=sectionsStart; sect < sectionsEnd; ++sect ) {
-                    if ( strncmp(info.sectionName.begin(), sect->sectname, 16) == 0 ) {
-                        sect->addr      = info.address;
-                        sect->size      = info.size;
-                        sect->offset    = info.fileOffset;
-                        sect->align     = info.alignment;
-                        sect->reloff    = info.relocsOffset;
-                        sect->nreloc    = info.relocsCount;
-                        sect->flags     = info.flags;
-                        sect->reserved1 = info.reserved1;
-                        sect->reserved2 = info.reserved2;
-                        sect->reserved3 = 0;
-                        stop = true;
-                        return;
-                    }
-                }
-            }
-        }
-        else if ( cmd->cmd == LC_SEGMENT ) {
-            segment_command* segCmd = (segment_command*)cmd;
-            if (info.segmentName == segCmd->segname) {
-                section* const  sectionsStart = (section*)((char*)segCmd + sizeof(struct segment_command));
-                section* const  sectionsEnd   = &sectionsStart[segCmd->nsects];
-                for ( section* sect=sectionsStart; sect < sectionsEnd; ++sect ) {
-                    if ( strncmp(info.sectionName.begin(), sect->sectname, 16) == 0 ) {
-                        sect->addr      = (uint32_t)info.address;
-                        sect->size      = (uint32_t)info.size;
-                        sect->offset    = info.fileOffset;
-                        sect->align     = info.alignment;
-                        sect->reloff    = info.relocsOffset;
-                        sect->nreloc    = info.relocsCount;
-                        sect->flags     = info.flags;
-                        sect->reserved1 = info.reserved1;
-                        sect->reserved2 = info.reserved2;
-                        stop = true;
-                        return;
-                    }
-                }
-            }
-        }
-    });
-}
-
-void HeaderWriter::updateSegment(const SegmentInfo& info)
-{
-    forEachLoadCommandSafe(^(const load_command* cmd, bool& stop) {
-        if ( cmd->cmd == LC_SEGMENT_64 ) {
-            segment_command_64* segCmd = (segment_command_64*)cmd;
-            if (info.segmentName == segCmd->segname) {
-                segCmd->vmaddr             = info.vmaddr;
-                segCmd->vmsize             = info.vmsize;
-                segCmd->fileoff            = info.fileOffset;
-                segCmd->filesize           = info.fileSize;
-                segCmd->maxprot            = info.maxProt;
-                segCmd->initprot           = info.initProt;
-                segCmd->flags              = info.flags;
-                stop = true;
-                return;
-            }
-        }
-        else if ( cmd->cmd == LC_SEGMENT ) {
-            segment_command* segCmd = (segment_command*)cmd;
-            if (info.segmentName == segCmd->segname) {
-                segCmd->vmaddr             = (uint32_t)info.vmaddr;
-                segCmd->vmsize             = (uint32_t)info.vmsize;
-                segCmd->fileoff            = info.fileOffset;
-                segCmd->filesize           = info.fileSize;
-                segCmd->maxprot            = info.maxProt;
-                segCmd->initprot           = info.initProt;
-                segCmd->flags              = info.flags;
-                stop = true;
-                return;
-            }
-        }
-    });
-}
-
-Error HeaderWriter::removeLoadCommands(uint32_t index, uint32_t endIndex)
-{
-    if ( index == endIndex )
-        return Error::none();
-
-    __block uint8_t* lcStart = nullptr;
-    __block uint8_t* lcRemoveStart = nullptr;
-    __block uint8_t* lcRemoveEnd = nullptr;
-
-    __block uint32_t currentIndex = 0;
-    forEachLoadCommandSafe(^(const load_command *cmd, bool &stop) {
-        if ( lcStart == nullptr )
-            lcStart = (uint8_t*)cmd;
-
-        if ( currentIndex == index ) {
-            lcRemoveStart = (uint8_t*)cmd;
-        } else if ( currentIndex == endIndex ) {
-            lcRemoveEnd = (uint8_t*)cmd;
-        }
-
-        ++currentIndex;
-        stop = lcRemoveStart != nullptr && lcRemoveEnd != nullptr;
-    });
-
-    if ( lcRemoveStart == nullptr || lcRemoveEnd == nullptr )
-        return Error("invalid load command range to remove");
-
-    uint8_t* lcEnd = lcStart+mh.sizeofcmds;
-    assert(lcRemoveStart >= lcStart && lcRemoveStart <= lcEnd);
-    assert(lcRemoveEnd >= lcStart && lcRemoveEnd <= lcEnd);
-    memmove(lcRemoveStart, lcRemoveEnd, (lcEnd-lcRemoveEnd));
-
-    mh.ncmds = mh.ncmds - (endIndex - index);
-    mh.sizeofcmds = mh.sizeofcmds - (uint32_t)(lcRemoveEnd-lcRemoveStart);
-    return Error::none();
-}
-
-load_command* HeaderWriter::insertLoadCommand(uint32_t atIndex, uint32_t cmdSize)
-{
-    if ( loadCommandsFreeSpace() < cmdSize )
-        return nullptr;
-
-    if ( pointerAligned(cmdSize) != cmdSize ) // command size needs to be pointer aligned
-        return nullptr;
-
-    uint8_t* lcStart = (uint8_t*)firstLoadCommand();
-    __block uint8_t* insertLocation = nullptr;
-    if ( atIndex == 0 ) {
-        insertLocation = lcStart;
-    } else if ( atIndex == mh.ncmds ) {
-        insertLocation = lcStart+mh.sizeofcmds;
-    } else {
-        __block uint32_t current = 0;
-        forEachLoadCommandSafe(^(const load_command *cmd, bool &stop) {
-            if ( current == atIndex ) {
-                insertLocation = (uint8_t*)cmd;
-                stop = true;
-            }
-            ++current;
-        });
-        if ( insertLocation == nullptr ) // invalid insert index
-            return nullptr;
-    }
-
-    // move existing load commands after the new location
-    memmove(insertLocation+cmdSize, insertLocation, (lcStart+mh.sizeofcmds)-insertLocation);
-
-    // update header
-    mh.ncmds += 1;
-    mh.sizeofcmds += cmdSize;
-
-    // set initial size
-    load_command* lcOut = (load_command*)insertLocation;
-    bzero(lcOut, cmdSize);
-    lcOut->cmdsize = cmdSize;
-    return lcOut;
-}
-
-void HeaderWriter::addInstallName(const char* name, Version32 compatVers, Version32 currentVersion)
-{
-    uint32_t       alignedSize      = pointerAligned((uint32_t)(sizeof(dylib_command) + strlen(name) + 1));
-    dylib_command* ic               = (dylib_command*)appendLoadCommand(LC_ID_DYLIB, alignedSize);
-    ic->dylib.name.offset           = sizeof(dylib_command);
-    ic->dylib.current_version       = currentVersion.value();
-    ic->dylib.compatibility_version = compatVers.value();
-    strcpy((char*)ic + ic->dylib.name.offset, name);
-}
-
-void HeaderWriter::addLinkedDylib(const char* path, LinkedDylibAttributes depAttrs, Version32 compatVers, Version32 currentVersion)
-{
-    uint32_t cmd  = 0;
-    uint32_t size = sizeForLinkedDylibCommand(path, depAttrs, cmd);
-
-    load_command* lc = appendLoadCommand(0, size);
-    setLinkedDylib(lc, path, depAttrs, compatVers, currentVersion);
-}
-
-void HeaderWriter::setLinkedDylib(load_command* lc, const char* path, LinkedDylibAttributes depAttrs, Version32 compatVers, Version32 currentVersion)
-{
-    uint32_t cmd = 0;
-    uint32_t size = sizeForLinkedDylibCommand(path, depAttrs, cmd);
-    assert(lc->cmdsize == size);
-
-    if ( cmd ) {
-        // make traditional load command
-        dylib_command* dc               = (dylib_command*)lc;
-        dc->cmd                         = cmd;
-        dc->dylib.name.offset           = sizeof(dylib_command);
-        dc->dylib.current_version       = currentVersion.value();
-        dc->dylib.compatibility_version = compatVers.value();
-        dc->dylib.timestamp             = 2; // needs to be some constant value that is different than dylib id load command;
-        strcpy((char*)dc + dc->dylib.name.offset, path);
-    }
-    else {
-        // make new style load command with extra flags field
-        if ( depAttrs.weakLink )
-            cmd = LC_LOAD_WEAK_DYLIB;
-        else
-            cmd = LC_LOAD_DYLIB;
-        dylib_use_command* dc     = (dylib_use_command*)lc;
-        dc->cmd                   = cmd;
-        dc->nameoff               = sizeof(dylib_use_command);
-        dc->current_version       = currentVersion.value();
-        dc->compat_version        = 0x00010000; // unused, but looks like 1.0 to old tools
-        dc->marker                = 0x1a741800; // magic value that means dylib_use_command
-        dc->flags                 = depAttrs.raw;
-        strcpy((char*)dc + dc->nameoff, path);
-    }
-}
-
-void HeaderWriter::addLibSystem()
-{
-    addLinkedDylib("/usr/lib/libSystem.B.dylib");
-}
-
-void HeaderWriter::addDylibId(CString name, Version32 compatVers, Version32 currentVersion)
-{
-    uint32_t       alignedSize          = pointerAligned((uint32_t)(sizeof(dylib_command) + name.size() + 1));
-    dylib_command* dc                   = (dylib_command*)appendLoadCommand(LC_ID_DYLIB, alignedSize);
-    dc->dylib.name.offset               = sizeof(dylib_command);
-    dc->dylib.timestamp                 = 1; // needs to be some constant value that is different than linked dylib
-    dc->dylib.current_version           = currentVersion.value();
-    dc->dylib.compatibility_version     = compatVers.value();
-    strcpy((char*)dc + dc->dylib.name.offset, name.c_str());
-}
-
-void HeaderWriter::addDyldID()
-{
-    const char* path = "/usr/lib/dyld";
-    uint32_t       alignedSize = pointerAligned((uint32_t)(sizeof(dylinker_command) + strlen(path) + 1));
-    dylinker_command* dc       = (dylinker_command*)appendLoadCommand(LC_ID_DYLINKER, alignedSize);
-    dc->name.offset = sizeof(dylinker_command);
-    strcpy((char*)dc + dc->name.offset, path);
-}
-
-void HeaderWriter::addDynamicLinker()
-{
-    const char* path = "/usr/lib/dyld";
-    uint32_t       alignedSize = pointerAligned((uint32_t)(sizeof(dylinker_command) + strlen(path) + 1));
-    dylinker_command* dc       = (dylinker_command*)appendLoadCommand(LC_LOAD_DYLINKER, alignedSize);
-    dc->name.offset = sizeof(dylinker_command);
-    strcpy((char*)dc + dc->name.offset, path);
-}
-
-void HeaderWriter::addFairPlayEncrypted(uint32_t offset, uint32_t size)
-{
-    if ( is64() ) {
-        encryption_info_command_64 en64;
-        en64.cmd       = LC_ENCRYPTION_INFO_64;
-        en64.cmdsize   = sizeof(encryption_info_command_64);
-        en64.cryptoff  = offset;
-        en64.cryptsize = size;
-        en64.cryptid   = 0;
-        en64.pad       = 0;
-        appendLoadCommand((load_command*)&en64);
-    }
-    else {
-        encryption_info_command en32;
-        en32.cmd       = LC_ENCRYPTION_INFO;
-        en32.cmdsize   = sizeof(encryption_info_command);
-        en32.cryptoff  = offset;
-        en32.cryptsize = size;
-        en32.cryptid   = 0;
-        appendLoadCommand((load_command*)&en32);
-    }
-}
-
-void HeaderWriter::addRPath(const char* path)
-{
-    uint32_t       alignedSize = pointerAligned((uint32_t)(sizeof(rpath_command) + strlen(path) + 1));
-    rpath_command* rc          = (rpath_command*)appendLoadCommand(LC_RPATH, alignedSize);
-    rc->path.offset            = sizeof(rpath_command);
-    strcpy((char*)rc + rc->path.offset, path);
-}
-
-void HeaderWriter::setTargetTriple(const char* triple)
-{
-    uint32_t               alignedSize = pointerAligned((uint32_t)(sizeof(target_triple_command) + strlen(triple) + 1));
-    target_triple_command* rc          = (target_triple_command*)appendLoadCommand(LC_TARGET_TRIPLE, alignedSize);
-    rc->triple.offset                  = sizeof(target_triple_command);
-    strcpy((char*)rc + rc->triple.offset, triple);
-}
-
-void HeaderWriter::addDyldEnvVar(const char* path)
-{
-    uint32_t          alignedSize = pointerAligned((uint32_t)(sizeof(dylinker_command) + strlen(path) + 1));
-    dylinker_command* dc          = (dylinker_command*)appendLoadCommand(LC_DYLD_ENVIRONMENT, alignedSize);
-    dc->name.offset               = sizeof(dylinker_command);
-    strcpy((char*)dc + dc->name.offset, path);
-}
-
-void HeaderWriter::addAllowableClient(const char* clientName)
-{
-    uint32_t            alignedSize = pointerAligned((uint32_t)(sizeof(sub_client_command) + strlen(clientName) + 1));
-    sub_client_command* ac          = (sub_client_command*)appendLoadCommand(LC_SUB_CLIENT, alignedSize);
-    ac->client.offset               = sizeof(sub_client_command);
-    strcpy((char*)ac + ac->client.offset, clientName);
-}
-
-void HeaderWriter::addUmbrellaName(const char* umbrellaName)
-{
-    uint32_t            alignedSize = pointerAligned((uint32_t)(sizeof(sub_framework_command) + strlen(umbrellaName) + 1));
-    sub_framework_command* ac       = (sub_framework_command*)appendLoadCommand(LC_SUB_FRAMEWORK, alignedSize);
-    ac->umbrella.offset             = sizeof(sub_framework_command);
-    strcpy((char*)ac + ac->umbrella.offset, umbrellaName);
-}
-
-void HeaderWriter::addSourceVersion(Version64 vers)
-{
-    source_version_command svc;
-    svc.cmd       = LC_SOURCE_VERSION;
-    svc.cmdsize   = sizeof(source_version_command);
-    svc.version   = vers.value();
-    appendLoadCommand((load_command*)&svc);
-}
-
-void HeaderWriter::setMain(uint32_t offset)
-{
-    entry_point_command ec;
-    ec.cmd       = LC_MAIN;
-    ec.cmdsize   = sizeof(entry_point_command);
-    ec.entryoff  = offset;
-    ec.stacksize = 0;
-    appendLoadCommand((load_command*)&ec);
-}
-
-void HeaderWriter::setCustomStackSize(uint64_t stackSize) {
-    __block bool found = false;
-    forEachLoadCommandSafe(^(const load_command* cmd, bool& stop) {
-        if (cmd->cmd == LC_MAIN) {
-            entry_point_command* ec = (entry_point_command*)cmd;
-            ec->stacksize           = stackSize;
-            found                   = true;
-            stop                    = true;
-        }
-    });
-    assert(found);
-}
-
-void HeaderWriter::setUnixEntry(uint64_t startAddr, bool entryIsThumb, uint64_t sp)
-{
-    // FIXME: support other archs
-    if ( (mh.cputype == CPU_TYPE_ARM64) || (mh.cputype == CPU_TYPE_ARM64_32) ) {
-        uint32_t   lcSize = threadLoadCommandsSize();
-        uint32_t*  words     = (uint32_t*)appendLoadCommand(LC_UNIXTHREAD, lcSize);
-        words[2] = 6;   // flavor = ARM_THREAD_STATE64
-        words[3] = 68;  // count  = ARM_EXCEPTION_STATE64_COUNT * 2 <=> 34 uint64_t's
-        bzero(&words[4], lcSize-16);
-        memcpy(&words[68], (uint8_t*)&startAddr, sizeof(uint64_t));  // register pc = startAddr
-        memcpy(&words[66], (uint8_t*)&sp, sizeof(uint64_t));         // register sp
-    }
-    else if ( mh.cputype == CPU_TYPE_X86_64 ) {
-        uint32_t   lcSize = threadLoadCommandsSize();
-        uint32_t*  words     = (uint32_t*)appendLoadCommand(LC_UNIXTHREAD, lcSize);
-        words[2] = 4;   // flavor = x86_THREAD_STATE64
-        words[3] = 42;  // count  = x86_THREAD_STATE64_COUNT
-        bzero(&words[4], lcSize-16);
-        memcpy(&words[36], &startAddr, 8);  // register pc = startAddr
-        memcpy(&words[18], &sp, 8);         //  register rsp
-    }
-    else if ( mh.cputype == CPU_TYPE_ARM ) {
-        uint32_t   lcSize = threadLoadCommandsSize();
-        uint32_t*  words     = (uint32_t*)appendLoadCommand(LC_UNIXTHREAD, lcSize);
-        words[2] = 1;   // flavor = ARM_THREAD_STATE
-        words[3] = 17;  // count  = ARM_THREAD_STATE_COUNT
-        bzero(&words[4], lcSize-16);
-        if ( entryIsThumb )
-            startAddr |= 1;
-        words[19] = (uint32_t)startAddr;  // register pc = startAddr
-        words[17] = (uint32_t)sp;
-    }
-    else {
-        assert(0 && "arch not supported");
-    }
-}
-
-void HeaderWriter::addCodeSignature(uint32_t fileOffset, uint32_t fileSize)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_CODE_SIGNATURE;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = fileOffset;
-    lc.datasize  = fileSize;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setBindOpcodesInfo(uint32_t rebaseOffset, uint32_t rebaseSize,
-                                      uint32_t bindsOffset, uint32_t bindsSize,
-                                      uint32_t weakBindsOffset, uint32_t weakBindsSize,
-                                      uint32_t lazyBindsOffset, uint32_t lazyBindsSize,
-                                      uint32_t exportTrieOffset, uint32_t exportTrieSize)
-{
-    dyld_info_command lc;
-    lc.cmd              = LC_DYLD_INFO_ONLY;
-    lc.cmdsize          = sizeof(dyld_info_command);
-    lc.rebase_off       = rebaseOffset;
-    lc.rebase_size      = rebaseSize;
-    lc.bind_off         = bindsOffset;
-    lc.bind_size        = bindsSize;
-    lc.weak_bind_off    = weakBindsOffset;
-    lc.weak_bind_size   = weakBindsSize;
-    lc.lazy_bind_off    = lazyBindsOffset;
-    lc.lazy_bind_size   = lazyBindsSize;
-    lc.export_off       = exportTrieOffset;
-    lc.export_size      = exportTrieSize;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setChainedFixupsInfo(uint32_t cfOffset, uint32_t cfSize)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_DYLD_CHAINED_FIXUPS;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = cfOffset;
-    lc.datasize  = cfSize;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setExportTrieInfo(uint32_t offset, uint32_t size)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_DYLD_EXPORTS_TRIE;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = offset;
-    lc.datasize  = size;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setFunctionVariants(uint32_t offset, uint32_t size)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_FUNCTION_VARIANTS;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = offset;
-    lc.datasize  = size;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setFunctionVariantFixups(uint32_t offset, uint32_t size)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_FUNCTION_VARIANT_FIXUPS;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = offset;
-    lc.datasize  = size;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setSplitSegInfo(uint32_t offset, uint32_t size)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_SEGMENT_SPLIT_INFO;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = offset;
-    lc.datasize  = size;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setDataInCode(uint32_t offset, uint32_t size)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_DATA_IN_CODE;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = offset;
-    lc.datasize  = size;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setFunctionStarts(uint32_t offset, uint32_t size)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_FUNCTION_STARTS;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = offset;
-    lc.datasize  = size;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setAtomInfo(uint32_t offset, uint32_t size)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_ATOM_INFO;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = offset;
-    lc.datasize  = size;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setLinkerOptimizationHints(uint32_t offset, uint32_t size)
-{
-    linkedit_data_command lc;
-    lc.cmd       = LC_LINKER_OPTIMIZATION_HINT;
-    lc.cmdsize   = sizeof(linkedit_data_command);
-    lc.dataoff   = offset;
-    lc.datasize  = size;
-    appendLoadCommand((load_command*)&lc);
-}
-
-void HeaderWriter::setSymbolTable(uint32_t nlistOffset, uint32_t nlistCount, uint32_t stringPoolOffset, uint32_t stringPoolSize,
-                                  uint32_t localsCount, uint32_t globalsCount, uint32_t undefCount, uint32_t indOffset, uint32_t indCount, bool dynSymtab,
-                                  uint32_t locrelOffset, uint32_t locrelCount, uint32_t extrelOffset, uint32_t extrelCount)
-{
-    symtab_command stc;
-    stc.cmd       = LC_SYMTAB;
-    stc.cmdsize   = sizeof(symtab_command);
-    stc.symoff    = nlistOffset;
-    stc.nsyms     = nlistCount;
-    stc.stroff    = stringPoolOffset;
-    stc.strsize   = stringPoolSize;
-    appendLoadCommand((load_command*)&stc);
-
-    if ( dynSymtab ) {
-        dysymtab_command dstc;
-        bzero(&dstc, sizeof(dstc));
-        dstc.cmd            = LC_DYSYMTAB;
-        dstc.cmdsize        = sizeof(dysymtab_command);
-        dstc.ilocalsym      = 0;
-        dstc.nlocalsym      = localsCount;
-        dstc.iextdefsym     = localsCount;
-        dstc.nextdefsym     = globalsCount;
-        dstc.iundefsym      = localsCount+globalsCount;
-        dstc.nundefsym      = undefCount;
-        dstc.indirectsymoff = indOffset;
-        dstc.nindirectsyms  = indCount;
-        dstc.locreloff      = locrelOffset;
-        dstc.nlocrel        = locrelCount;
-        dstc.extreloff      = extrelOffset;
-        dstc.nextrel        = extrelCount;
-        appendLoadCommand((load_command*)&dstc);
-    }
-}
-
-void HeaderWriter::addLinkerOption(std::span<uint8_t> buffer, uint32_t count)
-{
-    uint32_t cmdSize = pointerAligned(sizeof(linker_option_command) + (uint32_t)buffer.size());
-
-    linker_option_command* lc = (linker_option_command*)appendLoadCommand(LC_LINKER_OPTION, cmdSize);
-    lc->cmd     = LC_LINKER_OPTION;
-    lc->cmdsize = cmdSize;
-    lc->count   = count;
-    memcpy((uint8_t*)(lc + 1), buffer.data(), buffer.size());
-}
-
-HeaderWriter::LinkerOption HeaderWriter::LinkerOption::make(std::span<CString> opts)
-{
-    LinkerOption out;
-    out.count = (uint32_t)opts.size();
-    assert(out.count == opts.size());
-    for ( CString option : opts ) {
-        if ( option.empty() )
-            continue;
-        size_t previousSize = out.buffer.size();
-        out.buffer.resize(previousSize + option.size() + 1);
-        option.strcpy((char*)out.buffer.data() + previousSize);
-    }
-    return out;
-}
-
-load_command* HeaderWriter::findLoadCommand(uint32_t cmdNum)
-{
-    __block load_command* result = nullptr;
-    forEachLoadCommandSafe(^(const load_command* cmd, bool& stop) {
-        if ( cmd->cmd == cmdNum ) {
-            result = (load_command*)cmd;
-            stop   = true;
-        }
-    });
-    return result;
-}
-
-void HeaderWriter::removeLoadCommand(void (^callback)(const load_command* cmd, bool& remove, bool& stop))
-{
-    bool                stop      = false;
-    const load_command* startCmds = nullptr;
-    if ( mh.magic == MH_MAGIC_64 )
-        startCmds = (load_command*)((char*)this + sizeof(mach_header_64));
-    else if ( mh.magic == MH_MAGIC )
-        startCmds = (load_command*)((char*)this + sizeof(mach_header));
-    else if ( hasMachOBigEndianMagic() )
-        return; // can't process big endian mach-o
-    else {
-        //const uint32_t* h = (uint32_t*)this;
-        //diag.error("file does not start with MH_MAGIC[_64]: 0x%08X 0x%08X", h[0], h [1]);
-        return; // not a mach-o file
-    }
-    const load_command* const cmdsEnd        = (load_command*)((char*)startCmds + mh.sizeofcmds);
-    auto                      cmd            = (load_command*)startCmds;
-    const uint32_t            origNcmds      = mh.ncmds;
-    unsigned                  bytesRemaining = mh.sizeofcmds;
-    for ( uint32_t i = 0; i < origNcmds; ++i ) {
-        bool remove  = false;
-        auto nextCmd = (load_command*)((char*)cmd + cmd->cmdsize);
-        if ( cmd->cmdsize < 8 ) {
-            //diag.error("malformed load command #%d of %d at %p with mh=%p, size (0x%X) too small", i, mh.ncmds, cmd, this, cmd->cmdsize);
-            return;
-        }
-        if ( (nextCmd > cmdsEnd) || (nextCmd < startCmds) ) {
-            //diag.error("malformed load command #%d of %d at %p with mh=%p, size (0x%X) is too large, load commands end at %p", i, mh.ncmds, cmd, this, cmd->cmdsize, cmdsEnd);
-            return;
-        }
-        callback(cmd, remove, stop);
-        if ( remove ) {
-            mh.sizeofcmds -= cmd->cmdsize;
-            ::memmove((void*)cmd, (void*)nextCmd, bytesRemaining);
-            mh.ncmds--;
-        }
-        else {
-            bytesRemaining -= cmd->cmdsize;
-            cmd = nextCmd;
-        }
-        if ( stop )
-            break;
-    }
-    if ( cmd )
-        ::bzero(cmd, bytesRemaining);
-}
-
-uint32_t HeaderWriter::relocatableHeaderAndLoadCommandsSize(bool is64, uint32_t sectionCount, uint32_t platformsCount, std::span<const LinkerOption> linkerOptions)
-{
-    uint32_t size =  0;
-    if ( is64 ) {
-        size += sizeof(mach_header_64);
-        size += sizeof(segment_command_64);
-        size += sizeof(section_64) * sectionCount;
-    }
-    else {
-        size += sizeof(mach_header);
-        size += sizeof(segment_command);
-        size += sizeof(section) * sectionCount;
-    }
-    size += sizeof(symtab_command);
-    size += sizeof(dysymtab_command);
-    size += sizeof(build_version_command) * platformsCount;
-    size += sizeof(linkedit_data_command);
-
-    for ( LinkerOption opt : linkerOptions ) {
-        size += opt.lcSize();
-    }
-    return size;
-}
-
-void HeaderWriter::setRelocatableSectionCount(uint32_t sectionCount)
-{
-    assert(mh.filetype == MH_OBJECT);
-    if ( is64() ) {
-        uint32_t            lcSize = (uint32_t)(sizeof(segment_command_64) + sectionCount * sizeof(section_64));
-        segment_command_64* sc = (segment_command_64*)appendLoadCommand(LC_SEGMENT_64, lcSize);
-        sc->segname[0]         = '\0';   // MH_OBJECT has one segment with no name
-        sc->vmaddr             = 0;
-        sc->vmsize             = 0;   // adjusted in updateRelocatableSegmentSize()
-        sc->fileoff            = 0;
-        sc->filesize           = 0;   // adjusted in updateRelocatableSegmentSize()
-        sc->maxprot            = 7;
-        sc->initprot           = 7;
-        sc->nsects             = sectionCount;
-        // section info to be filled in later by setRelocatableSectionInfo()
-        bzero((uint8_t*)sc + sizeof(segment_command_64), sectionCount * sizeof(section_64));
-    }
-    else {
-        uint32_t            lcSize = (uint32_t)(sizeof(segment_command) + sectionCount * sizeof(section));
-        segment_command* sc = (segment_command*)appendLoadCommand(LC_SEGMENT, lcSize);
-        sc->segname[0]         = '\0';   // MH_OBJECT has one segment with no name
-        sc->vmaddr             = 0;
-        sc->vmsize             = 0x1000; // FIXME: need dynamic segment layout
-        sc->fileoff            = 0;
-        sc->filesize           = 0x1000;
-        sc->maxprot            = 7;
-        sc->initprot           = 7;
-        sc->nsects             = sectionCount;
-        // section info to be filled in later by setRelocatableSectionInfo()
-        bzero((uint8_t*)sc + sizeof(segment_command), sectionCount * sizeof(struct section));
-    }
-}
-
-void HeaderWriter::updateRelocatableSegmentSize(uint64_t vmSize, uint32_t fileSize)
-{
-    forEachLoadCommandSafe(^(const load_command* cmd, bool& stop) {
-        if ( cmd->cmd == LC_SEGMENT ) {
-            segment_command* sc = (segment_command*)cmd;
-            sc->vmsize   = (uint32_t)vmSize;
-            sc->filesize = fileSize;
-            stop = true;
-        }
-        else if ( cmd->cmd == LC_SEGMENT_64 ) {
-            segment_command_64* sc = (segment_command_64*)cmd;
-            sc->vmsize   = vmSize;
-            sc->filesize = fileSize;
-            stop = true;
-        }
-    });
-}
-
-
-void HeaderWriter::setRelocatableSectionInfo(uint32_t sectionIndex, const char* segName, const char* sectName,
-                                             uint32_t flags, uint64_t address, uint64_t size, uint32_t fileOffset,
-                                             uint16_t alignment, uint32_t relocsOffset, uint32_t relocsCount)
-{
-    __block struct section*    section32 = nullptr;
-    __block struct section_64* section64 = nullptr;
-    forEachLoadCommandSafe(^(const load_command* cmd, bool& stop) {
-        if ( cmd->cmd == LC_SEGMENT ) {
-            struct section* sections = (struct section*)((uint8_t*)cmd + sizeof(segment_command));
-            section32 = &sections[sectionIndex];
-            stop = true;
-        }
-        else if ( cmd->cmd == LC_SEGMENT_64 ) {
-            struct section_64* sections = (struct section_64*)((uint8_t*)cmd + sizeof(segment_command_64));
-            section64 = &sections[sectionIndex];
-            stop = true;
-        }
-    });
-    if ( section64 != nullptr ) {
-        strncpy(section64->segname,  segName, 16);
-        strncpy(section64->sectname, sectName, 16);
-        section64->addr      = address;
-        section64->size      = size;
-        section64->offset    = fileOffset;
-        section64->align     = alignment;
-        section64->reloff    = relocsOffset;
-        section64->nreloc    = relocsCount;
-        section64->flags     = flags;
-        section64->reserved1 = 0;
-        section64->reserved2 = 0;
-        section64->reserved3 = 0;
-    }
-    else if ( section32 != nullptr ) {
-        strncpy(section32->segname,  segName, 16);
-        strncpy(section32->sectname, sectName, 16);
-        section32->addr      = (uint32_t)address;
-        section32->size      = (uint32_t)size;
-        section32->offset    = fileOffset;
-        section32->align     = alignment;
-        section32->reloff    = relocsOffset;
-        section32->nreloc    = relocsCount;
-        section32->flags     = flags;
-        section32->reserved1 = 0;
-        section32->reserved2 = 0;
-    }
-}
-
-
-} // namespace dyld3