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--- dyld/dyld-519.2.2/src/dyldInitialization.cpp
+++ dyld/dyld-43/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@
*
@@ -22,56 +22,31 @@
* @APPLE_LICENSE_HEADER_END@
*/
-#define __STDC_LIMIT_MACROS
-#include <stdint.h>
#include <stddef.h>
#include <string.h>
-#include <stdlib.h>
-#include <Availability.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>
+#if __ppc__ || __ppc64__
+ #include <mach-o/ppc/reloc.h>
#endif
#include "dyld.h"
-#include "dyldSyscallInterface.h"
-
-// from dyld_gdb.cpp
-extern void addImagesToAllImages(uint32_t infoCount, const dyld_image_info info[]);
-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 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
-#if __x86_64__
- #define POINTER_RELOC X86_64_RELOC_UNSIGNED
-#else
- #define POINTER_RELOC GENERIC_RELOC_VANILLA
-#endif
-
-
-#if TARGET_IPHONE_SIMULATOR
-const dyld::SyscallHelpers* gSyscallHelpers = NULL;
-#endif
-
//
// Code to bootstrap dyld into a runnable state
@@ -81,13 +56,7 @@
namespace dyldbootstrap {
-
-#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.
@@ -97,31 +66,32 @@
//
static void runDyldInitializers(const struct macho_header* mh, intptr_t slide, 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
-
-
-//
-// The kernel may have slid a Position Independent Executable
-//
-static uintptr_t slideOfMainExecutable(const struct macho_header* mh)
-{
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;
- }
+ 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);
}
- return 0;
}
@@ -131,16 +101,13 @@
//
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
+ // 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;
-#if __x86_64__
- const struct macho_segment_command* firstWritableSeg = NULL;
-#endif
const struct dysymtab_command* dynamicSymbolTable = NULL;
+ const struct macho_section* nonLazySection = NULL;
for (uint32_t i = 0; i < cmd_count; ++i) {
switch (cmd->cmd) {
case LC_SEGMENT_COMMAND:
@@ -152,19 +119,9 @@
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 ( type == S_NON_LAZY_SYMBOL_POINTERS )
+ nonLazySection = sect;
}
-#if __x86_64__
- if ( (firstWritableSeg == NULL) && (seg->initprot & VM_PROT_WRITE) )
- firstWritableSeg = seg;
-#endif
}
break;
case LC_DYSYMTAB:
@@ -175,47 +132,105 @@
}
// use reloc's to rebase all random data pointers
-#if __x86_64__
- 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;
- }
-}
-
-
+ if ( (reloc->r_address & R_SCATTERED) == 0 ) {
+ if (reloc->r_length == RELOC_SIZE) {
+ switch(reloc->r_type) {
+ case GENERIC_RELOC_VANILLA:
+ *((uintptr_t*)(reloc->r_address + relocBase)) += slide;
+ break;
+ }
+ }
+ }
+ else {
+ const struct scattered_relocation_info* sreloc = (struct scattered_relocation_info*)reloc;
+ if (sreloc->r_length == RELOC_SIZE) {
+ uintptr_t* locationToFix = (uintptr_t*)(sreloc->r_address + relocBase);
+ switch(sreloc->r_type) {
+ case GENERIC_RELOC_VANILLA:
+ #if __ppc__ || __ppc64__
+ case PPC_RELOC_PB_LA_PTR:
+ #elif __i386__
+ case GENERIC_RELOC_PB_LA_PTR:
+ #endif
+ // Note the use of PB_LA_PTR is unique here. Seems like ld should strip out all lazy pointers
+ // but it does not. But, since all lazy-pointers point within dyld, they can be slid too
+ *locationToFix += slide;
+ break;
+ }
+ }
+ }
+ }
+
+ // rebase non-lazy pointers (which all point internal to dyld, since dyld uses no shared libraries)
+ if ( nonLazySection != NULL ) {
+ const uint32_t pointerCount = nonLazySection->size / sizeof(uintptr_t);
+ uintptr_t* const symbolPointers = (uintptr_t*)(nonLazySection->addr + slide);
+ for (uint32_t j=0; j < pointerCount; ++j) {
+ symbolPointers[j] += 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();
-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 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
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];
@@ -224,55 +239,14 @@
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(dyldsMachHeader, slide, 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);
-}
-
-
-#if TARGET_IPHONE_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 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 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;
-
- // allow dyld to use mach messaging
- mach_init();
-
- // 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 = slideOfMainExecutable(mainExecutableMH);
- return dyld::_main(mainExecutableMH, appsSlide, argc, argv, envp, apple, startGlue);
-}
-#endif
+ return dyld::_main(appsMachHeader, argc, argv, envp, apple);
+}
+
+
} // end of namespace