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--- dyld/dyld-625.13/src/dyldInitialization.cpp
+++ dyld/dyld-750.6/src/dyldInitialization.cpp
@@ -27,67 +27,23 @@
#include <stddef.h>
#include <string.h>
#include <stdlib.h>
-#include <Availability.h>
+#include <sys/mman.h>
#include <mach/mach.h>
-#include <mach-o/loader.h>
-#include <mach-o/ldsyms.h>
-#include <mach-o/reloc.h>
-#if __x86_64__
- #include <mach-o/x86_64/reloc.h>
-#endif
-#include "dyld.h"
+
+#include "dyld2.h"
#include "dyldSyscallInterface.h"
+#include "MachOAnalyzer.h"
+#include "Tracing.h"
-// from dyld_gdb.cpp
-extern void addImagesToAllImages(uint32_t infoCount, const dyld_image_info info[]);
+// from libc.a
+extern "C" void mach_init();
+extern "C" void __guard_setup(const char* apple[]);
+
+
+// from dyld_debugger.cpp
extern void syncProcessInfo();
-#ifndef MH_PIE
- #define MH_PIE 0x200000
-#endif
-
-// currently dyld has no initializers, but if some come back, set this to non-zero
-#define DYLD_INITIALIZER_SUPPORT 0
-
-#if __LP64__
- #define LC_SEGMENT_COMMAND LC_SEGMENT_64
- #define macho_segment_command segment_command_64
- #define macho_section section_64
- #define RELOC_SIZE 3
-#else
- #define LC_SEGMENT_COMMAND LC_SEGMENT
- #define macho_segment_command segment_command
- #define macho_section section
- #define RELOC_SIZE 2
-#endif
-
-#if __x86_64__
- #define POINTER_RELOC X86_64_RELOC_UNSIGNED
-#else
- #define POINTER_RELOC GENERIC_RELOC_VANILLA
-#endif
-
-#ifndef BIND_OPCODE_THREADED
-#define BIND_OPCODE_THREADED 0xD0
-#endif
-
-#ifndef BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB
-#define BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB 0x00
-#endif
-
-#ifndef BIND_SUBOPCODE_THREADED_APPLY
-#define BIND_SUBOPCODE_THREADED_APPLY 0x01
-#endif
-
-
-#if __has_feature(ptrauth_calls)
-#include <ptrauth.h>
-#endif
-
-
-#if TARGET_IPHONE_SIMULATOR
const dyld::SyscallHelpers* gSyscallHelpers = NULL;
-#endif
//
@@ -97,6 +53,9 @@
namespace dyldbootstrap {
+
+// currently dyld has no initializers, but if some come back, set this to non-zero
+#define DYLD_INITIALIZER_SUPPORT 0
#if DYLD_INITIALIZER_SUPPORT
@@ -112,7 +71,7 @@
// dyld (should be static) but is a dynamic executable and needs this hack to run its own initializers.
// We pass argc, argv, etc in case libc.a uses those arguments
//
-static void runDyldInitializers(const struct macho_header* mh, intptr_t slide, int argc, const char* argv[], const char* envp[], const char* apple[])
+static void runDyldInitializers(int argc, const char* argv[], const char* envp[], const char* apple[])
{
for (const Initializer* p = &inits_start; p < &inits_end; ++p) {
(*p)(argc, argv, envp, apple);
@@ -122,366 +81,48 @@
//
-// The kernel may have slid a Position Independent Executable
+// On disk, all pointers in dyld's DATA segment are chained together.
+// They need to be fixed up to be real pointers to run.
//
-static uintptr_t slideOfMainExecutable(const struct macho_header* mh)
+static void rebaseDyld(const dyld3::MachOLoaded* dyldMH)
{
- const uint32_t cmd_count = mh->ncmds;
- const struct load_command* const cmds = (struct load_command*)(((char*)mh)+sizeof(macho_header));
- const struct load_command* cmd = cmds;
- for (uint32_t i = 0; i < cmd_count; ++i) {
- if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
- const struct macho_segment_command* segCmd = (struct macho_segment_command*)cmd;
- if ( (segCmd->fileoff == 0) && (segCmd->filesize != 0)) {
- return (uintptr_t)mh - segCmd->vmaddr;
- }
- }
- cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
- }
- return 0;
+ // walk all fixups chains and rebase dyld
+ const dyld3::MachOAnalyzer* ma = (dyld3::MachOAnalyzer*)dyldMH;
+ assert(ma->hasChainedFixups());
+ uintptr_t slide = (long)ma; // all fixup chain based images have a base address of zero, so slide == load address
+ __block Diagnostics diag;
+ ma->withChainStarts(diag, 0, ^(const dyld_chained_starts_in_image* starts) {
+ ma->fixupAllChainedFixups(diag, starts, slide, dyld3::Array<const void*>(), nullptr);
+ });
+ diag.assertNoError();
+
+ // now that rebasing done, initialize mach/syscall layer
+ mach_init();
+
+ // <rdar://47805386> mark __DATA_CONST segment in dyld as read-only (once fixups are done)
+ ma->forEachSegment(^(const dyld3::MachOFile::SegmentInfo& info, bool& stop) {
+ if ( info.readOnlyData ) {
+ ::mprotect(((uint8_t*)(dyldMH))+info.vmAddr, (size_t)info.vmSize, VM_PROT_READ);
+ }
+ });
}
-inline uint64_t read_uleb128(const uint8_t*& p, const uint8_t* end) {
- uint64_t result = 0;
- int bit = 0;
- do {
- if (p == end)
- throw "malformed uleb128 extends beyond trie";
- uint64_t slice = *p & 0x7f;
-
- if (bit >= 64 || slice << bit >> bit != slice)
- throw "uleb128 too big for 64-bits";
- else {
- result |= (slice << bit);
- bit += 7;
- }
- }
- while (*p++ & 0x80);
- return result;
-}
-
-inline int64_t read_sleb128(const uint8_t*& p, const uint8_t* end)
-{
- int64_t result = 0;
- int bit = 0;
- uint8_t byte;
- do {
- if (p == end)
- throw "malformed sleb128";
- byte = *p++;
- result |= (((int64_t)(byte & 0x7f)) << bit);
- bit += 7;
- } while (byte & 0x80);
- // sign extend negative numbers
- if ( (byte & 0x40) != 0 )
- result |= (~0ULL) << bit;
- return result;
-}
-
-
-//
-// If the kernel does not load dyld at its preferred address, we need to apply
-// fixups to various initialized parts of the __DATA segment
-//
-static void rebaseDyld(const struct macho_header* mh, intptr_t slide)
-{
- // rebase non-lazy pointers (which all point internal to dyld, since dyld uses no shared libraries)
- // and get interesting pointers into dyld
- const uint32_t cmd_count = mh->ncmds;
- const struct load_command* const cmds = (struct load_command*)(((char*)mh)+sizeof(macho_header));
- const struct load_command* cmd = cmds;
-
- // First look for compressed info and use it if it exists.
- const struct macho_segment_command* linkEditSeg = NULL;
- const dyld_info_command* dyldInfoCmd = NULL;
- for (uint32_t i = 0; i < cmd_count; ++i) {
- switch (cmd->cmd) {
- case LC_SEGMENT_COMMAND:
- {
- const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
- if ( strcmp(seg->segname, "__LINKEDIT") == 0 )
- linkEditSeg = seg;
- break;
- }
- case LC_DYLD_INFO_ONLY:
- dyldInfoCmd = (struct dyld_info_command*)cmd;
- break;
- }
- if (dyldInfoCmd && linkEditSeg)
- break;
- cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
- }
- if ( linkEditSeg == NULL )
- throw "dyld missing LINKEDIT";
-
- // Reset the iterator.
- cmd = cmds;
-
- auto getSegmentAtIndex = [cmd_count, cmds](unsigned segIndex) -> const struct macho_segment_command* {
- const struct load_command* cmd = cmds;
- for (uint32_t i = 0; i < cmd_count; ++i) {
- switch (cmd->cmd) {
- case LC_SEGMENT_COMMAND:
- if (!segIndex) {
- const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
- return seg;
- }
- --segIndex;
- break;
- }
- cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
- }
- throw "out of bounds command";
- return 0;
- };
-
- auto segActualLoadAddress = [&](unsigned segIndex) -> uintptr_t {
- const struct macho_segment_command* seg = getSegmentAtIndex(segIndex);
- return seg->vmaddr + slide;
- };
-
-#if __has_feature(ptrauth_calls)
- auto imageBaseAddress = [cmds, cmd_count]() -> uintptr_t {
- const struct load_command* cmd = cmds;
- for (uint32_t i = 0; i < cmd_count; ++i) {
- switch (cmd->cmd) {
- case LC_SEGMENT_COMMAND: {
- const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
- if ( (seg->fileoff == 0) && (seg->filesize != 0) )
- return seg->vmaddr;
- break;
- }
- }
- cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
- }
- return 0;
- };
-#endif
-
- if (dyldInfoCmd && (dyldInfoCmd->bind_size != 0) ) {
- if ( dyldInfoCmd->rebase_size != 0 )
- throw "unthreaded rebases are not supported";
-
- const uint8_t* linkEditBase = (uint8_t*)(linkEditSeg->vmaddr + slide - linkEditSeg->fileoff);
-
- const uint8_t* const start = linkEditBase + dyldInfoCmd->bind_off;
- const uint8_t* const end = &start[dyldInfoCmd->bind_size];
- const uint8_t* p = start;
-
- uintptr_t segmentStartAddress = 0;
- uint64_t segOffset = 0;
- int segIndex = 0;
-#if __has_feature(ptrauth_calls)
- uintptr_t fBaseAddress = imageBaseAddress();
-#endif
- bool done = false;
-
- while ( !done && (p < end) ) {
- uint8_t immediate = *p & BIND_IMMEDIATE_MASK;
- uint8_t opcode = *p & BIND_OPCODE_MASK;
- ++p;
- switch (opcode) {
- case BIND_OPCODE_DONE:
- done = true;
- break;
- case BIND_OPCODE_SET_DYLIB_ORDINAL_IMM:
- break;
- case BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB:
- break;
- case BIND_OPCODE_SET_DYLIB_SPECIAL_IMM:
- break;
- case BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM:
- while (*p != '\0')
- ++p;
- ++p;
- break;
- case BIND_OPCODE_SET_TYPE_IMM:
- break;
- case BIND_OPCODE_SET_ADDEND_SLEB:
- read_sleb128(p, end);
- break;
- case BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB:
- segIndex = immediate;
- segmentStartAddress = segActualLoadAddress(segIndex);
- segOffset = read_uleb128(p, end);
- break;
- case BIND_OPCODE_ADD_ADDR_ULEB:
- segOffset += read_uleb128(p, end);
- break;
- case BIND_OPCODE_DO_BIND:
- break;
- case BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB:
- break;
- case BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED:
- break;
- case BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB:
- read_uleb128(p, end);
- read_uleb128(p, end);
- break;
- case BIND_OPCODE_THREADED:
- // Note the immediate is a sub opcode
- switch (immediate) {
- case BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB:
- read_uleb128(p, end);
- break;
- case BIND_SUBOPCODE_THREADED_APPLY: {
- uint64_t delta = 0;
- do {
- uintptr_t address = segmentStartAddress + (uintptr_t)segOffset;
- uint64_t value = *(uint64_t*)address;
-
-#if __has_feature(ptrauth_calls)
- uint16_t diversity = (uint16_t)(value >> 32);
- bool hasAddressDiversity = (value & (1ULL << 48)) != 0;
- ptrauth_key key = (ptrauth_key)((value >> 49) & 0x3);
- bool isAuthenticated = (value & (1ULL << 63)) != 0;
-#endif
- bool isRebase = (value & (1ULL << 62)) == 0;
- if (isRebase) {
-
-#if __has_feature(ptrauth_calls)
- if (isAuthenticated) {
- // The new value for a rebase is the low 32-bits of the threaded value plus the slide.
- uint64_t newValue = (value & 0xFFFFFFFF) + slide;
- // Add in the offset from the mach_header
- newValue += fBaseAddress;
- // We have bits to merge in to the discriminator
- uintptr_t discriminator = diversity;
- if (hasAddressDiversity) {
- // First calculate a new discriminator using the address of where we are trying to store the value
- discriminator = __builtin_ptrauth_blend_discriminator((void*)address, discriminator);
- }
- switch (key) {
- case ptrauth_key_asia:
- newValue = (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)newValue, ptrauth_key_asia, discriminator);
- break;
- case ptrauth_key_asib:
- newValue = (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)newValue, ptrauth_key_asib, discriminator);
- break;
- case ptrauth_key_asda:
- newValue = (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)newValue, ptrauth_key_asda, discriminator);
- break;
- case ptrauth_key_asdb:
- newValue = (uintptr_t)__builtin_ptrauth_sign_unauthenticated((void*)newValue, ptrauth_key_asdb, discriminator);
- break;
- }
- *(uint64_t*)address = newValue;
- } else
-#endif
- {
- // Regular pointer which needs to fit in 51-bits of value.
- // C++ RTTI uses the top bit, so we'll allow the whole top-byte
- // and the signed-extended bottom 43-bits to be fit in to 51-bits.
- uint64_t top8Bits = value & 0x0007F80000000000ULL;
- uint64_t bottom43Bits = value & 0x000007FFFFFFFFFFULL;
- uint64_t targetValue = ( top8Bits << 13 ) | (((intptr_t)(bottom43Bits << 21) >> 21) & 0x00FFFFFFFFFFFFFF);
- targetValue = targetValue + slide;
- *(uint64_t*)address = targetValue;
- }
- }
-
- // The delta is bits [51..61]
- // And bit 62 is to tell us if we are a rebase (0) or bind (1)
- value &= ~(1ULL << 62);
- delta = ( value & 0x3FF8000000000000 ) >> 51;
- segOffset += delta * sizeof(uintptr_t);
- } while ( delta != 0 );
- break;
- }
- default:
- throw "unknown threaded bind subopcode";
- }
- break;
- default:
- throw "unknown bind opcode";
- }
- }
- return;
- }
-
-#if __x86_64__
- const struct macho_segment_command* firstWritableSeg = NULL;
-#endif
- const struct dysymtab_command* dynamicSymbolTable = NULL;
- for (uint32_t i = 0; i < cmd_count; ++i) {
- switch (cmd->cmd) {
- case LC_SEGMENT_COMMAND:
- {
- const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
- const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
- const struct macho_section* const sectionsEnd = §ionsStart[seg->nsects];
- for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
- const uint8_t type = sect->flags & SECTION_TYPE;
- if ( type == S_NON_LAZY_SYMBOL_POINTERS ) {
- // rebase non-lazy pointers (which all point internal to dyld, since dyld uses no shared libraries)
- const uint32_t pointerCount = (uint32_t)(sect->size / sizeof(uintptr_t));
- uintptr_t* const symbolPointers = (uintptr_t*)(sect->addr + slide);
- for (uint32_t j=0; j < pointerCount; ++j) {
- symbolPointers[j] += slide;
- }
- }
- }
-#if __x86_64__
- if ( (firstWritableSeg == NULL) && (seg->initprot & VM_PROT_WRITE) )
- firstWritableSeg = seg;
-#endif
- }
- break;
- case LC_DYSYMTAB:
- dynamicSymbolTable = (struct dysymtab_command *)cmd;
- break;
- }
- cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
- }
-
- // use reloc's to rebase all random data pointers
-#if __x86_64__
- if ( firstWritableSeg == NULL )
- throw "no writable segment in dyld";
- const uintptr_t relocBase = firstWritableSeg->vmaddr + slide;
-#else
- const uintptr_t relocBase = (uintptr_t)mh;
-#endif
- const relocation_info* const relocsStart = (struct relocation_info*)(linkEditSeg->vmaddr + slide + dynamicSymbolTable->locreloff - linkEditSeg->fileoff);
- const relocation_info* const relocsEnd = &relocsStart[dynamicSymbolTable->nlocrel];
- for (const relocation_info* reloc=relocsStart; reloc < relocsEnd; ++reloc) {
- if ( reloc->r_length != RELOC_SIZE )
- throw "relocation in dyld has wrong size";
-
- if ( reloc->r_type != POINTER_RELOC )
- throw "relocation in dyld has wrong type";
-
- // update pointer by amount dyld slid
- *((uintptr_t*)(reloc->r_address + relocBase)) += slide;
- }
-}
-
-
-extern "C" void mach_init();
-extern "C" void __guard_setup(const char* apple[]);
//
// This is code to bootstrap dyld. This work in normally done for a program by dyld and crt.
// In dyld we have to do this manually.
//
-uintptr_t start(const struct macho_header* appsMachHeader, int argc, const char* argv[],
- intptr_t slide, const struct macho_header* dyldsMachHeader,
- uintptr_t* startGlue)
+uintptr_t start(const dyld3::MachOLoaded* appsMachHeader, int argc, const char* argv[],
+ const dyld3::MachOLoaded* dyldsMachHeader, uintptr_t* startGlue)
{
+
+ // Emit kdebug tracepoint to indicate dyld bootstrap has started <rdar://46878536>
+ dyld3::kdebug_trace_dyld_marker(DBG_DYLD_TIMING_BOOTSTRAP_START, 0, 0, 0, 0);
+
// if kernel had to slide dyld, we need to fix up load sensitive locations
// we have to do this before using any global variables
- slide = slideOfMainExecutable(dyldsMachHeader);
- bool shouldRebase = slide != 0;
-#if __has_feature(ptrauth_calls)
- shouldRebase = true;
-#endif
- if ( shouldRebase ) {
- rebaseDyld(dyldsMachHeader, slide);
- }
-
- // allow dyld to use mach messaging
- mach_init();
+ rebaseDyld(dyldsMachHeader);
// kernel sets up env pointer to be just past end of agv array
const char** envp = &argv[argc+1];
@@ -496,37 +137,31 @@
#if DYLD_INITIALIZER_SUPPORT
// run all C++ initializers inside dyld
- runDyldInitializers(dyldsMachHeader, slide, argc, argv, envp, apple);
+ runDyldInitializers(argc, argv, envp, apple);
#endif
// now that we are done bootstrapping dyld, call dyld's main
- uintptr_t appsSlide = slideOfMainExecutable(appsMachHeader);
- return dyld::_main(appsMachHeader, appsSlide, argc, argv, envp, apple, startGlue);
+ uintptr_t appsSlide = appsMachHeader->getSlide();
+ return dyld::_main((macho_header*)appsMachHeader, appsSlide, argc, argv, envp, apple, startGlue);
}
-#if TARGET_IPHONE_SIMULATOR
+#if TARGET_OS_SIMULATOR
extern "C" uintptr_t start_sim(int argc, const char* argv[], const char* envp[], const char* apple[],
- const macho_header* mainExecutableMH, const macho_header* dyldMH, uintptr_t dyldSlide,
+ const dyld3::MachOLoaded* mainExecutableMH, const dyld3::MachOLoaded* dyldMH, uintptr_t dyldSlide,
const dyld::SyscallHelpers*, uintptr_t* startGlue);
-
+
uintptr_t start_sim(int argc, const char* argv[], const char* envp[], const char* apple[],
- const macho_header* mainExecutableMH, const macho_header* dyldMH, uintptr_t dyldSlide,
+ const dyld3::MachOLoaded* mainExecutableMH, const dyld3::MachOLoaded* dyldSimMH, uintptr_t dyldSlide,
const dyld::SyscallHelpers* sc, uintptr_t* startGlue)
{
- // if simulator dyld loaded slid, it needs to rebase itself
- // we have to do this before using any global variables
- if ( dyldSlide != 0 ) {
- rebaseDyld(dyldMH, dyldSlide);
- }
+ // save table of syscall pointers
+ gSyscallHelpers = sc;
- // save table of syscall pointers
- gSyscallHelpers = sc;
-
- // allow dyld to use mach messaging
- mach_init();
+ // dyld_sim uses chained rebases, so it always need to be fixed up
+ rebaseDyld(dyldSimMH);
// set up random value for stack canary
__guard_setup(apple);
@@ -536,8 +171,8 @@
syncProcessInfo();
// now that we are done bootstrapping dyld, call dyld's main
- uintptr_t appsSlide = slideOfMainExecutable(mainExecutableMH);
- return dyld::_main(mainExecutableMH, appsSlide, argc, argv, envp, apple, startGlue);
+ uintptr_t appsSlide = mainExecutableMH->getSlide();
+ return dyld::_main((macho_header*)mainExecutableMH, appsSlide, argc, argv, envp, apple, startGlue);
}
#endif