Loading...
--- dyld/dyld-43/src/dyldInitialization.cpp
+++ dyld/dyld-195.5/src/dyldInitialization.cpp
@@ -1,6 +1,6 @@
/* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
*
- * Copyright (c) 2004-2005 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 2004-2008 Apple Inc. All rights reserved.
*
* @APPLE_LICENSE_HEADER_START@
*
@@ -22,8 +22,11 @@
* @APPLE_LICENSE_HEADER_END@
*/
+#define __STDC_LIMIT_MACROS
+#include <stdint.h>
#include <stddef.h>
#include <string.h>
+#include <stdlib.h>
#include <mach/mach.h>
#include <mach-o/loader.h>
#include <mach-o/ldsyms.h>
@@ -31,21 +34,36 @@
#if __ppc__ || __ppc64__
#include <mach-o/ppc/reloc.h>
#endif
+#if __x86_64__
+ #include <mach-o/x86_64/reloc.h>
+#endif
#include "dyld.h"
+#ifndef MH_PIE
+ #define MH_PIE 0x200000
+#endif
+
+
#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
+
+// from dyld.cpp
+namespace dyld { extern bool isRosetta(); };
//
@@ -96,18 +114,42 @@
//
+// 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 ( strcmp(segCmd->segname, "__TEXT") == 0 ) {
+ return (uintptr_t)mh - segCmd->vmaddr;
+ }
+ }
+ cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
+ }
+ return 0;
+}
+
+
+//
// 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)
{
- // get interesting pointers into dyld
+ // 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;
+#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:
@@ -119,9 +161,19 @@
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 )
- nonLazySection = sect;
+ 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;
+ }
+ }
}
+#if __x86_64__
+ if ( (firstWritableSeg == NULL) && (seg->initprot & VM_PROT_WRITE) )
+ firstWritableSeg = seg;
+#endif
}
break;
case LC_DYSYMTAB:
@@ -132,105 +184,70 @@
}
// 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_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);
- }
-
-}
+ #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;
+ }
+}
+
extern "C" void dyld_exceptions_init(const struct macho_header*, uintptr_t slide); // in dyldExceptions.cpp
extern "C" void mach_init();
//
+// _pthread_keys is partitioned in a lower part that dyld will use; libSystem
+// will use the upper part. We set __pthread_tsd_first to 1 as the start of
+// the lower part. Libc will take #1 and c++ exceptions will take #2. There
+// is one free key=3 left.
+//
+extern "C" {
+ extern int __pthread_tsd_first;
+ extern void _pthread_keys_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 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);
-
+uintptr_t start(const struct macho_header* appsMachHeader, int argc, const char* argv[],
+ intptr_t slide, const struct macho_header* dyldsMachHeader)
+{
// 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);
}
-
+
+#if __IPHONE_OS_VERSION_MIN_REQUIRED
+ // set pthread keys to dyld range
+ __pthread_tsd_first = 1;
+ _pthread_keys_init();
+#endif
+
// 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];
@@ -241,9 +258,10 @@
// run all C++ initializers inside dyld
runDyldInitializers(dyldsMachHeader, slide, argc, argv, envp, apple);
-
+
// now that we are done bootstrapping dyld, call dyld's main
- return dyld::_main(appsMachHeader, argc, argv, envp, apple);
+ uintptr_t appsSlide = slideOfMainExecutable(appsMachHeader);
+ return dyld::_main(appsMachHeader, appsSlide, argc, argv, envp, apple);
}