/* -*- 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@
*
#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 __ppc__ || __ppc64__
- #include <mach-o/ppc/reloc.h>
-#endif
#if __x86_64__
#include <mach-o/x86_64/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 POINTER_RELOC GENERIC_RELOC_VANILLA
#endif
-// from dyld.cpp
-namespace dyld { extern bool isRosetta(); };
+
+#if TARGET_IPHONE_SIMULATOR
+const dyld::SyscallHelpers* gSyscallHelpers = NULL;
+#endif
//
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.
// For a static executable, crt directly runs the 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[])
+{
+ 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) {
- 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;
+ 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
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);
+ 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;
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";
}
-//
-// 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);
- //dyld::log("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);
- }
-
-}
-
-
-//
-// re-map the main executable to a new random address
-//
-static const struct mach_header* randomizeExecutableLoadAddress(const struct mach_header* orgMH, uintptr_t* appsSlide)
-{
-#if __ppc__
- // don't slide PIE programs running under rosetta
- if ( dyld::isRosetta() )
- return orgMH;
-#endif
- // count segments
- uint32_t segCount = 0;
- const uint32_t cmd_count = orgMH->ncmds;
- const struct load_command* const cmds = (struct load_command*)(((char*)orgMH)+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;
- // page-zero and custom stacks don't move
- if ( (strcmp(segCmd->segname, "__PAGEZERO") != 0) && (strcmp(segCmd->segname, "__UNIXSTACK") != 0) )
- ++segCount;
- }
- cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
- }
-
- // make copy of segment info
- macho_segment_command segs[segCount];
- uint32_t index = 0;
- uintptr_t highestAddressUsed = 0;
- uintptr_t lowestAddressUsed = UINTPTR_MAX;
- 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, "__PAGEZERO") != 0) && (strcmp(segCmd->segname, "__UNIXSTACK") != 0) ) {
- segs[index++] = *segCmd;
- if ( (segCmd->vmaddr + segCmd->vmsize) > highestAddressUsed )
- highestAddressUsed = ((segCmd->vmaddr + segCmd->vmsize) + 4095) & -4096;
- if ( segCmd->vmaddr < lowestAddressUsed )
- lowestAddressUsed = segCmd->vmaddr;
- // do nothing if kernel has already randomized load address
- if ( (strcmp(segCmd->segname, "__TEXT") == 0) && (segCmd->vmaddr != (uintptr_t)orgMH) )
- return orgMH;
- }
- }
- cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
- }
-
- // choose a random new base address
-#if __LP64__
- uintptr_t highestAddressPossible = highestAddressUsed + 0x100000000ULL;
-#else
- uintptr_t highestAddressPossible = 0x80000000;
-#endif
- uintptr_t sizeNeeded = highestAddressUsed-lowestAddressUsed;
- if ( (highestAddressPossible-sizeNeeded) < highestAddressUsed ) {
- // new and old segments will overlap
- // need better algorithm for remapping
- // punt and don't re-map
- return orgMH;
- }
- uintptr_t possibleRange = (highestAddressPossible-sizeNeeded) - highestAddressUsed;
- uintptr_t newBaseAddress = highestAddressUsed + ((arc4random() % possibleRange) & -4096);
-
- vm_address_t addr = newBaseAddress;
- // reserve new address range
- if ( vm_allocate(mach_task_self(), &addr, sizeNeeded, VM_FLAGS_FIXED) == KERN_SUCCESS ) {
- // copy each segment to new address
- for (uint32_t i = 0; i < segCount; ++i) {
- uintptr_t newSegAddress = segs[i].vmaddr - lowestAddressUsed + newBaseAddress;
- if ( (vm_copy(mach_task_self(), segs[i].vmaddr, segs[i].vmsize, newSegAddress) != KERN_SUCCESS)
- || (vm_protect(mach_task_self(), newSegAddress, segs[i].vmsize, true, segs[i].maxprot) != KERN_SUCCESS)
- || (vm_protect(mach_task_self(), newSegAddress, segs[i].vmsize, false, segs[i].initprot) != KERN_SUCCESS) ) {
- // can't copy so dealloc new region and run with original base address
- vm_deallocate(mach_task_self(), newBaseAddress, sizeNeeded);
- dyld::warn("could not relocate position independent exectable\n");
- return orgMH;
- }
- }
- // unmap original segments
- vm_deallocate(mach_task_self(), lowestAddressUsed, highestAddressUsed-lowestAddressUsed);
-
- // run with newly mapped executable
- *appsSlide = newBaseAddress - lowestAddressUsed;
- return (const struct mach_header*)newBaseAddress;
- }
-
- // can't get new range, so don't slide to random address
- return orgMH;
-}
-
-
-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();
-}
+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 mach_header* appsMachHeader, int argc, const char* argv[], intptr_t slide)
+uintptr_t start(const struct macho_header* appsMachHeader, int argc, const char* argv[],
+ intptr_t slide, const struct macho_header* dyldsMachHeader,
+ uintptr_t* startGlue)
{
- // _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);
}
-
- uintptr_t appsSlide = 0;
-
- // set pthread keys to dyld range
- __pthread_tsd_first = 1;
- _pthread_keys_init();
-
- // 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];
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);
-
- // if main executable was linked -pie, then randomize its load address
- if ( appsMachHeader->flags & MH_PIE )
- appsMachHeader = randomizeExecutableLoadAddress(appsMachHeader, &appsSlide);
-
+#endif
+
// now that we are done bootstrapping dyld, call dyld's main
- return dyld::_main(appsMachHeader, appsSlide, argc, argv, envp, apple);
+ 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
} // end of namespace
projects / apple / dyld.git / blobdiff