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--- dyld/dyld-852/src/dyldInitialization.cpp
+++ dyld/dyld-45.1/src/dyldInitialization.cpp
@@ -1,6 +1,6 @@
/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
*
- * Copyright (c) 2004-2008 Apple Inc. All rights reserved.
+ * Copyright (c) 2004-2005 Apple Computer, Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
@@ -22,29 +22,32 @@
* @APPLE_LICENSE_HEADER_END@
*/
-#define __STDC_LIMIT_MACROS
-#include <stdint.h>
#include <stddef.h>
#include <string.h>
-#include <stdlib.h>
-#include <sys/mman.h>
#include <mach/mach.h>
-
-#include "dyld2.h"
-#include "dyldSyscallInterface.h"
-#include "MachOAnalyzer.h"
-#include "Tracing.h"
-
-// from libc.a
-extern "C" void mach_init();
-extern "C" void __guard_setup(const char* apple[]);
-extern "C" void _subsystem_init(const char* apple[]);
-
-// from dyld_debugger.cpp
-extern void syncProcessInfo();
-
-const dyld::SyscallHelpers* gSyscallHelpers = NULL;
-
+#include <mach-o/loader.h>
+#include <mach-o/ldsyms.h>
+#include <mach-o/reloc.h>
+#if __ppc__ || __ppc64__
+ #include <mach-o/ppc/reloc.h>
+#endif
+#include "dyld.h"
+
+#if __LP64__
+ #define macho_header mach_header_64
+ #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 macho_header mach_header
+ #define LC_SEGMENT_COMMAND LC_SEGMENT
+ #define macho_segment_command segment_command
+ #define macho_section section
+ #define RELOC_SIZE 2
+#endif
+
+ #define POINTER_RELOC GENERIC_RELOC_VANILLA
//
// Code to bootstrap dyld into a runnable state
@@ -54,16 +57,7 @@
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
-
typedef void (*Initializer)(int argc, const char* argv[], const char* envp[], const char* apple[]);
-
-extern const Initializer inits_start __asm("section$start$__DATA$__mod_init_func");
-extern const Initializer inits_end __asm("section$end$__DATA$__mod_init_func");
//
// For a regular executable, the crt code calls dyld to run the executables initializers.
@@ -71,59 +65,153 @@
// 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(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);
- }
-}
-#endif // DYLD_INITIALIZER_SUPPORT
-
-
-//
-// 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 void rebaseDyld(const dyld3::MachOLoaded* dyldMH)
-{
- // 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);
- }
- });
-}
-
-
+static void runDyldInitializers(const struct macho_header* mh, intptr_t slide, int argc, const char* argv[], const char* envp[], const char* apple[])
+{
+ 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) {
+ 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_MOD_INIT_FUNC_POINTERS ){
+ Initializer* inits = (Initializer*)(sect->addr + slide);
+ const uint32_t count = sect->size / sizeof(uintptr_t);
+ for (uint32_t i=0; i < count; ++i) {
+ Initializer func = inits[i];
+ func(argc, argv, envp, apple);
+ }
+ }
+ }
+ }
+ break;
+ }
+ cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+ }
+}
+
+//
+// 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;
+ const struct macho_segment_command* linkEditSeg = NULL;
+ 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;
+ if ( strcmp(seg->segname, "__LINKEDIT") == 0 )
+ linkEditSeg = seg;
+ 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 = 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;
+ }
+ }
+ }
+ }
+ 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
+ const uintptr_t relocBase = (uintptr_t)mh;
+ 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 __ppc__ || __ppc64__ || __i36__
+ if ( (reloc->r_address & R_SCATTERED) != 0 )
+ throw "scattered relocation in dyld";
+ #endif
+ 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;
+ }
+}
+
+
+//
+// For some reason the kernel loads dyld with __TEXT and __LINKEDIT writable
+// rdar://problem/3702311
+//
+static void segmentProtectDyld(const struct macho_header* mh, intptr_t slide)
+{
+ 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) {
+ switch (cmd->cmd) {
+ case LC_SEGMENT_COMMAND:
+ {
+ const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
+ vm_address_t addr = seg->vmaddr + slide;
+ vm_size_t size = seg->vmsize;
+ const bool setCurrentPermissions = false;
+ vm_protect(mach_task_self(), addr, size, setCurrentPermissions, seg->initprot);
+ //fprintf(stderr, "dyld: segment %s, 0x%08X -> 0x%08X, set to %d\n", seg->segname, addr, addr+size-1, seg->initprot);
+ }
+ break;
+ }
+ cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+ }
+
+}
+
+extern "C" void dyld_exceptions_init(const struct macho_header*, uintptr_t slide); // in dyldExceptions.cpp
+extern "C" void mach_init();
//
// 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 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);
-
+uintptr_t start(const struct mach_header* appsMachHeader, int argc, const char* argv[], intptr_t slide)
+{
+ // _mh_dylinker_header is magic symbol defined by static linker (ld), see <mach-o/ldsyms.h>
+ const struct macho_header* dyldsMachHeader = (const struct macho_header*)(((char*)&_mh_dylinker_header)+slide);
+
// if kernel had to slide dyld, we need to fix up load sensitive locations
// we have to do this before using any global variables
- rebaseDyld(dyldsMachHeader);
-
+ if ( slide != 0 ) {
+ rebaseDyld(dyldsMachHeader, slide);
+ }
+
+ // enable C++ exceptions to work inside dyld
+ dyld_exceptions_init(dyldsMachHeader, slide);
+
+ // allow dyld to use mach messaging
+ mach_init();
+
+ // set protection on segments (has to be done after mach_init)
+ segmentProtectDyld(dyldsMachHeader, slide);
+
// kernel sets up env pointer to be just past end of agv array
const char** envp = &argv[argc+1];
@@ -132,51 +220,14 @@
while(*apple != NULL) { ++apple; }
++apple;
- // set up random value for stack canary
- __guard_setup(apple);
-
-#if DYLD_INITIALIZER_SUPPORT
// run all C++ initializers inside dyld
- runDyldInitializers(argc, argv, envp, apple);
-#endif
-
- _subsystem_init(apple);
-
+ runDyldInitializers(dyldsMachHeader, slide, argc, argv, envp, apple);
+
// now that we are done bootstrapping dyld, call dyld's main
- uintptr_t appsSlide = appsMachHeader->getSlide();
- return dyld::_main((macho_header*)appsMachHeader, appsSlide, argc, argv, envp, apple, startGlue);
-}
-
-
-#if TARGET_OS_SIMULATOR
-
-extern "C" uintptr_t start_sim(int argc, const char* argv[], const char* envp[], const char* apple[],
- 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 dyld3::MachOLoaded* mainExecutableMH, const dyld3::MachOLoaded* dyldSimMH, uintptr_t dyldSlide,
- const dyld::SyscallHelpers* sc, uintptr_t* startGlue)
-{
- // save table of syscall pointers
- gSyscallHelpers = sc;
-
- // 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);
-
- // setup gProcessInfo to point to host dyld's struct
- dyld::gProcessInfo = (struct dyld_all_image_infos*)(sc->getProcessInfo());
- syncProcessInfo();
-
- // now that we are done bootstrapping dyld, call dyld's main
- uintptr_t appsSlide = mainExecutableMH->getSlide();
- return dyld::_main((macho_header*)mainExecutableMH, appsSlide, argc, argv, envp, apple, startGlue);
-}
-#endif
+ return dyld::_main(appsMachHeader, argc, argv, envp, apple);
+}
+
+
} // end of namespace