]> git.saurik.com Git - apple/dyld.git/blob - src/ImageLoaderMachO.cpp
projects / apple / dyld.git / blob
? search:
summary | shortlog | log | commit | commitdiff | tree
blame | history | raw | HEAD
dyld-46.16.tar.gz
[apple/dyld.git] / src / ImageLoaderMachO.cpp
1 /* -*- mode: C++; c-basic-offset: 4; tab-width: 4 -*-
2 *
3 * Copyright (c) 2004-2005 Apple Computer, Inc. All rights reserved.
4 *
5 * @APPLE_LICENSE_HEADER_START@
6 *
7 * This file contains Original Code and/or Modifications of Original Code
8 * as defined in and that are subject to the Apple Public Source License
9 * Version 2.0 (the 'License'). You may not use this file except in
10 * compliance with the License. Please obtain a copy of the License at
11 * http://www.opensource.apple.com/apsl/ and read it before using this
12 * file.
13 *
14 * The Original Code and all software distributed under the License are
15 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
16 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
17 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
19 * Please see the License for the specific language governing rights and
20 * limitations under the License.
21 *
22 * @APPLE_LICENSE_HEADER_END@
23 */
24
25 #include <string.h>
26 #include <fcntl.h>
27 #include <sys/types.h>
28 #include <sys/stat.h>
29 #include <sys/mman.h>
30 #include <mach/shared_memory_server.h>
31 #include <mach/mach.h>
32 #include <mach/thread_status.h>
33 #include <mach-o/loader.h>
34 #include <mach-o/reloc.h>
35 #include <mach-o/nlist.h>
36 #include <sys/sysctl.h>
37 #include <libkern/OSAtomic.h>
38 #if __ppc__ || __ppc64__
39 #include <mach-o/ppc/reloc.h>
40 #endif
41 #if __x86_64__
42 #include <mach-o/x86_64/reloc.h>
43 #endif
44
45 #ifndef S_ATTR_SELF_MODIFYING_CODE
46 #define S_ATTR_SELF_MODIFYING_CODE 0x04000000
47 #endif
48
49 #include "ImageLoaderMachO.h"
50 #include "mach-o/dyld_gdb.h"
51
52 // no header for this yet, rdar://problem/3850825
53 extern "C" void sys_icache_invalidate(void *, size_t);
54
55 // optimize strcmp for ppc
56 #if __ppc__
57 #include <ppc_intrinsics.h>
58 #else
59 #define astrcmp(a,b) strcmp(a,b)
60 #endif
61
62 // relocation_info.r_length field has value 3 for 64-bit executables and value 2 for 32-bit executables
63 #if __LP64__
64 #define RELOC_SIZE 3
65 #define LC_SEGMENT_COMMAND LC_SEGMENT_64
66 #define LC_ROUTINES_COMMAND LC_ROUTINES_64
67 struct macho_header : public mach_header_64 {};
68 struct macho_segment_command : public segment_command_64 {};
69 struct macho_section : public section_64 {};
70 struct macho_nlist : public nlist_64 {};
71 struct macho_routines_command : public routines_command_64 {};
72 #else
73 #define RELOC_SIZE 2
74 #define LC_SEGMENT_COMMAND LC_SEGMENT
75 #define LC_ROUTINES_COMMAND LC_ROUTINES
76 struct macho_header : public mach_header {};
77 struct macho_segment_command : public segment_command {};
78 struct macho_section : public section {};
79 struct macho_nlist : public nlist {};
80 struct macho_routines_command : public routines_command {};
81 #endif
82
83 #if __x86_64__
84 #define POINTER_RELOC X86_64_RELOC_UNSIGNED
85 #else
86 #define POINTER_RELOC GENERIC_RELOC_VANILLA
87 #endif
88
89 uint32_t ImageLoaderMachO::fgHintedBinaryTreeSearchs = 0;
90 uint32_t ImageLoaderMachO::fgUnhintedBinaryTreeSearchs = 0;
91 uint32_t ImageLoaderMachO::fgCountOfImagesWithWeakExports = 0;
92
93
94 //#define LINKEDIT_USAGE_DEBUG 1
95
96 #if LINKEDIT_USAGE_DEBUG
97 #include <set>
98 static std::set<uintptr_t> sLinkEditPageBuckets;
99
100 namespace dyld {
101 extern ImageLoader* findImageContainingAddress(const void* addr);
102 };
103
104 static void noteAccessedLinkEditAddress(const void* addr)
105 {
106 uintptr_t page = ((uintptr_t)addr) & (-4096);
107 sLinkEditPageBuckets.insert(page);
108 fprintf(stderr, "dyld: accessing page 0x%08lX in __LINKEDIT of %s\n", page, dyld::findImageContainingAddress(addr)->getPath());
109 }
110 #endif
111
112 // only way to share initialization in C++
113 void ImageLoaderMachO::init()
114 {
115 fMachOData = NULL;
116 fLinkEditBase = NULL;
117 fSymbolTable = NULL;
118 fStrings = NULL;
119 fDynamicInfo = NULL;
120 fSlide = 0;
121 fIsSplitSeg = false;
122 fHasSubLibraries= false;
123 fHasSubUmbrella = false;
124 fDashInit = NULL;
125 fModInitSection = NULL;
126 fModTermSection = NULL;
127 fDATAdyld = NULL;
128 fImageNotifySection = NULL;
129 fTwoLevelHints = NULL;
130 fDylibID = NULL;
131 fReExportThruFramework = NULL;
132 fTextSegmentWithFixups = NULL;
133 }
134
135 // create image by copying an in-memory mach-o file
136 ImageLoaderMachO::ImageLoaderMachO(const char* moduleName, const struct mach_header* mh, uint64_t len, const LinkContext& context)
137 : ImageLoader(moduleName)
138 {
139 // clean slate
140 this->init();
141
142 // temporary use this buffer until TEXT is mapped in
143 fMachOData = (const uint8_t*)mh;
144
145 // create segments
146 this->instantiateSegments((const uint8_t*)mh);
147
148 // map segments
149 if ( mh->filetype != MH_EXECUTE )
150 ImageLoader::mapSegments((const void*)mh, len, context);
151
152 // get pointers to interesting things
153 this->parseLoadCmds();
154 }
155
156
157 // create image by mapping in a mach-o file
158 ImageLoaderMachO::ImageLoaderMachO(const char* path, int fd, const uint8_t firstPage[4096], uint64_t offsetInFat,
159 uint64_t lenInFat, const struct stat& info, const LinkContext& context)
160 : ImageLoader(path, offsetInFat, info)
161 {
162 // clean slate
163 this->init();
164
165 // read load commands
166 const unsigned int dataSize = sizeof(macho_header) + ((macho_header*)firstPage)->sizeofcmds;
167 uint8_t buffer[dataSize];
168 const uint8_t* fileData = firstPage;
169 if ( dataSize > 4096 ) {
170 // only read more if cmds take up more space than first page
171 fileData = buffer;
172 memcpy(buffer, firstPage, 4096);
173 pread(fd, &buffer[4096], dataSize-4096, offsetInFat+4096);
174 }
175
176 // temporary use this buffer until TEXT is mapped in
177 fMachOData = fileData;
178
179 // the meaning of many fields changes in split seg mach-o files
180 fIsSplitSeg = ((((macho_header*)fileData)->flags & MH_SPLIT_SEGS) != 0) && (((macho_header*)fileData)->filetype == MH_DYLIB);
181
182 // create segments
183 this->instantiateSegments(fileData);
184
185 // map segments, except for main executable which is already mapped in by kernel
186 if ( ((macho_header*)fileData)->filetype != MH_EXECUTE )
187 this->mapSegments(fd, offsetInFat, lenInFat, info.st_size, context);
188
189 // get pointers to interesting things
190 this->parseLoadCmds();
191 }
192
193 ImageLoaderMachO::~ImageLoaderMachO()
194 {
195 // keep count of images with weak exports
196 if ( this->hasCoalescedExports() )
197 --fgCountOfImagesWithWeakExports;
198 }
199
200
201
202 void ImageLoaderMachO::instantiateSegments(const uint8_t* fileData)
203 {
204 const uint32_t cmd_count = ((macho_header*)fileData)->ncmds;
205 const struct load_command* const cmds = (struct load_command*)&fileData[sizeof(macho_header)];
206
207 // construct Segment object for each LC_SEGMENT cmd and add to list
208 const struct load_command* cmd = cmds;
209 for (unsigned long i = 0; i < cmd_count; ++i) {
210 if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
211 if ( (((struct macho_segment_command*)cmd)->vmsize != 0) || !fIsSplitSeg )
212 fSegments.push_back(new SegmentMachO((struct macho_segment_command*)cmd, this, fileData));
213 }
214 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
215 }
216 }
217
218
219
220 bool ImageLoaderMachO::segmentsMustSlideTogether() const
221 {
222 return true;
223 }
224
225 bool ImageLoaderMachO::segmentsCanSlide() const
226 {
227 const macho_header* mh = (macho_header*)fMachOData;
228 return ( (mh->filetype == MH_DYLIB) || (mh->filetype == MH_BUNDLE) );
229 }
230
231 bool ImageLoaderMachO::isBundle() const
232 {
233 const macho_header* mh = (macho_header*)fMachOData;
234 return ( mh->filetype == MH_BUNDLE );
235 }
236
237 bool ImageLoaderMachO::isDylib() const
238 {
239 const macho_header* mh = (macho_header*)fMachOData;
240 return ( mh->filetype == MH_DYLIB );
241 }
242
243 bool ImageLoaderMachO::forceFlat() const
244 {
245 const macho_header* mh = (macho_header*)fMachOData;
246 return ( (mh->flags & MH_FORCE_FLAT) != 0 );
247 }
248
249 bool ImageLoaderMachO::usesTwoLevelNameSpace() const
250 {
251 const macho_header* mh = (macho_header*)fMachOData;
252 return ( (mh->flags & MH_TWOLEVEL) != 0 );
253 }
254
255 bool ImageLoaderMachO::isPrebindable() const
256 {
257 const macho_header* mh = (macho_header*)fMachOData;
258 return ( (mh->flags & MH_PREBOUND) != 0 );
259 }
260
261 bool ImageLoaderMachO::hasCoalescedExports() const
262 {
263 const macho_header* mh = (macho_header*)fMachOData;
264 return ( (mh->flags & MH_WEAK_DEFINES) != 0 );
265 }
266
267 bool ImageLoaderMachO::needsCoalescing() const
268 {
269 const macho_header* mh = (macho_header*)fMachOData;
270 return ( (mh->flags & MH_BINDS_TO_WEAK) != 0 );
271 }
272
273 #if !__LP64__ // split segs not supported for 64-bits
274
275 #if 1 // hack until kernel headers and glue are in system
276 struct _shared_region_mapping_np {
277 mach_vm_address_t address;
278 mach_vm_size_t size;
279 mach_vm_offset_t file_offset;
280 vm_prot_t max_prot; /* read/write/execute/COW/ZF */
281 vm_prot_t init_prot; /* read/write/execute/COW/ZF */
282 };
283 struct _shared_region_range_np {
284 mach_vm_address_t address;
285 mach_vm_size_t size;
286 };
287
288 // Called by dyld.
289 // Requests the kernel to map a number of regions from the fd into the
290 // shared sections address range (0x90000000-0xAFFFFFFF).
291 // If shared_region_make_private_np() has not been called by this process,
292 // the file mapped in is seen in the address space of all processes that
293 // participate in using the shared region.
294 // If shared_region_make_private_np() _has_ been called by this process,
295 // the file mapped in is only seen by this process.
296 // If the slide parameter is not NULL and then regions cannot be mapped
297 // as requested, the kernel will try to map the file in at a different
298 // address in the shared region and return the distance slid.
299 // If the mapping requesting cannot be fulfilled, returns non-zero.
300 static int
301 _shared_region_map_file_np(
302 int fd, // file descriptor to map into shared region
303 unsigned int regionCount, // number of entres in array of regions
304 const _shared_region_mapping_np regions[], // the array of regions to map
305 uint64_t* slide) // the amount all regions were slid, NULL means don't attempt to slide
306 {
307 //fprintf(stderr, "%s(%i, %u, %8p, %8p)\n", __func__, fd, regionCount, regions, slide);
308 //for ( unsigned int i=0; i < regionCount; ++i) {
309 // fprintf(stderr, "\taddress=0x%08llX, size=0x%08llX\n", regions[i].address, regions[i].size);
310 //}
311 int r = syscall(299, fd, regionCount, regions, slide);
312 // if(0 != r)
313 // fprintf(stderr, "%s(%i, %u, %8p, %8p) errno=%i (%s)\n", __func__, fd, regionCount, regions, slide, errno, strerror(errno));
314 return r;
315 }
316 // Called by dyld if shared_region_map_file() fails.
317 // Requests the kernel to take this process out of using the shared region.
318 // The specified ranges are created as private copies from the shared region for this process.
319 static int
320 _shared_region_make_private_np(
321 unsigned int rangeCount, // number of entres in array of msrp_range
322 const _shared_region_range_np ranges[]) // the array of shared regions to make private
323 {
324 //fprintf(stderr, "%s(%u, %8p)\n", __func__, rangeCount, ranges);
325 int r = syscall(300, rangeCount, ranges);
326 // if(0 != r)
327 // fprintf(stderr, "%s(%u, %8p) errno=%i (%s)\n", __func__, rangeCount, ranges, errno, strerror(errno));
328 return r;
329 }
330 #define KERN_SHREG_PRIVATIZABLE 54
331 #endif // hack until kernel headers and glue are in system
332
333 static uintptr_t sNextAltLoadAddress
334 #if __ppc_
335 = 0xC0000000;
336 #else
337 = 0;
338 #endif
339
340 static int
341 _shared_region_map_file_with_mmap(
342 int fd, // file descriptor to map into shared region
343 unsigned int regionCount, // number of entres in array of regions
344 const _shared_region_mapping_np regions[]) // the array of regions to map
345 {
346 // map in each region
347 for(unsigned int i=0; i < regionCount; ++i) {
348 void* mmapAddress = (void*)(uintptr_t)(regions[i].address);
349 size_t size = regions[i].size;
350 if ( (regions[i].init_prot & VM_PROT_ZF) != 0 ) {
351 // do nothing already vm_allocate() which zero fills
352 }
353 else {
354 int protection = 0;
355 if ( regions[i].init_prot & VM_PROT_EXECUTE )
356 protection |= PROT_EXEC;
357 if ( regions[i].init_prot & VM_PROT_READ )
358 protection |= PROT_READ;
359 if ( regions[i].init_prot & VM_PROT_WRITE )
360 protection |= PROT_WRITE;
361 off_t offset = regions[i].file_offset;
362 //fprintf(stderr, "mmap(%p, 0x%08lX, block=0x%08X, %s\n", mmapAddress, size, biggestDiff, fPath);
363 mmapAddress = mmap(mmapAddress, size, protection, MAP_FILE | MAP_FIXED | MAP_PRIVATE, fd, offset);
364 if ( mmapAddress == ((void*)(-1)) )
365 throw "mmap error";
366 }
367 }
368
369 return 0;
370 }
371
372
373 static
374 bool
375 hasSharedRegionMapFile(void)
376 {
377 int mib[CTL_MAXNAME];
378 int value = 0;
379 size_t size;
380
381 mib[0] = CTL_KERN;
382 mib[1] = KERN_SHREG_PRIVATIZABLE;
383 size = sizeof (int);
384 if (sysctl(mib, 2, &value, &size, NULL, 0) != 0) {
385 value = 0;
386 }
387
388 return 0 != value;
389 }
390
391 int
392 ImageLoaderMachO::sharedRegionMapFilePrivateOutside(int fd,
393 uint64_t offsetInFat,
394 uint64_t lenInFat,
395 uint64_t fileLen,
396 const LinkContext& context)
397 {
398 const unsigned int segmentCount = fSegments.size();
399 const unsigned int extraZeroFillEntries = getExtraZeroFillEntriesCount();
400 const unsigned int regionCount = segmentCount+extraZeroFillEntries;
401 _shared_region_mapping_np regions[regionCount];
402 initMappingTable(offsetInFat, regions);
403 int r = -1;
404 // find space somewhere to allocate split seg
405 bool foundRoom = false;
406 vm_size_t biggestDiff = 0;
407 while ( ! foundRoom ) {
408 foundRoom = true;
409 for(unsigned int i=0; i < regionCount; ++i) {
410 vm_address_t addr = sNextAltLoadAddress + regions[i].address - regions[0].address;
411 vm_size_t size = regions[i].size ;
412 r = vm_allocate(mach_task_self(), &addr, size, false /*only this range*/);
413 if ( 0 != r ) {
414 // no room here, deallocate what has succeeded so far
415 for(unsigned int j=0; j < i; ++j) {
416 vm_address_t addr = sNextAltLoadAddress + regions[j].address - regions[0].address;
417 vm_size_t size = regions[j].size ;
418 (void)vm_deallocate(mach_task_self(), addr, size);
419 }
420 sNextAltLoadAddress += 0x00100000; // skip ahead 1MB and try again
421 if ( (sNextAltLoadAddress & 0xF0000000) == 0x90000000 )
422 sNextAltLoadAddress = 0xB0000000;
423 if ( (sNextAltLoadAddress & 0xF0000000) == 0xF0000000 )
424 throw "can't map split seg anywhere";
425 foundRoom = false;
426 break;
427 }
428 vm_size_t high = (regions[i].address + size - regions[0].address) & 0x0FFFFFFF;
429 if ( high > biggestDiff )
430 biggestDiff = high;
431 }
432 }
433
434 // map in each region
435 uintptr_t slide = sNextAltLoadAddress - regions[0].address;
436 this->setSlide(slide);
437 for(unsigned int i=0; i < regionCount; ++i) {
438 if ( (regions[i].init_prot & VM_PROT_ZF) != 0 ) {
439 // do nothing vm_allocate() zero-fills by default
440 }
441 else {
442 void* mmapAddress = (void*)(uintptr_t)(regions[i].address + slide);
443 size_t size = regions[i].size;
444 int protection = 0;
445 if ( regions[i].init_prot & VM_PROT_EXECUTE )
446 protection |= PROT_EXEC;
447 if ( regions[i].init_prot & VM_PROT_READ )
448 protection |= PROT_READ;
449 if ( regions[i].init_prot & VM_PROT_WRITE )
450 protection |= PROT_WRITE;
451 off_t offset = regions[i].file_offset;
452 //fprintf(stderr, "mmap(%p, 0x%08lX, block=0x%08X, %s\n", mmapAddress, size, biggestDiff, fPath);
453 mmapAddress = mmap(mmapAddress, size, protection, MAP_FILE | MAP_FIXED | MAP_PRIVATE, fd, offset);
454 if ( mmapAddress == ((void*)(-1)) )
455 throw "mmap error";
456 }
457 }
458 // set so next maps right after this one
459 sNextAltLoadAddress += biggestDiff;
460 sNextAltLoadAddress = (sNextAltLoadAddress + 4095) & (-4096);
461
462 // logging
463 if ( context.verboseMapping ) {
464 fprintf(stderr, "dyld: Mapping split-seg outside shared region, slid by 0x%08lX %s\n", this->fSlide, this->getPath());
465 for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
466 Segment* seg = fSegments[segIndex];
467 const _shared_region_mapping_np* entry = &regions[entryIndex];
468 if ( (entry->init_prot & VM_PROT_ZF) == 0 )
469 fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
470 seg->getName(), seg->getActualLoadAddress(), seg->getActualLoadAddress()+seg->getFileSize()-1);
471 if ( entryIndex < (regionCount-1) ) {
472 const _shared_region_mapping_np* nextEntry = &regions[entryIndex+1];
473 if ( (nextEntry->init_prot & VM_PROT_ZF) != 0 ) {
474 uint64_t segOffset = nextEntry->address - entry->address;
475 fprintf(stderr, "%18s at 0x%08lX->0x%08lX (zerofill)\n",
476 seg->getName(), (uintptr_t)(seg->getActualLoadAddress() + segOffset), (uintptr_t)(seg->getActualLoadAddress() + segOffset + nextEntry->size - 1));
477 ++entryIndex;
478 }
479 }
480 }
481 }
482
483 return r;
484 }
485
486
487 void ImageLoaderMachO::mapSegments(int fd, uint64_t offsetInFat, uint64_t lenInFat, uint64_t fileLen, const LinkContext& context)
488 {
489 enum SharedRegionState
490 {
491 kSharedRegionStartState = 0,
492 kSharedRegionLoadFileState,
493 kSharedRegionMapFileState,
494 kSharedRegionMapFilePrivateState,
495 kSharedRegionMapFilePrivateMMapState,
496 kSharedRegionMapFilePrivateOutsideState,
497 };
498 static SharedRegionState sSharedRegionState = kSharedRegionStartState;
499
500 // non-split segment libraries handled by super class
501 if ( !fIsSplitSeg )
502 return ImageLoader::mapSegments(fd, offsetInFat, lenInFat, fileLen, context);
503
504 if ( kSharedRegionStartState == sSharedRegionState ) {
505 if ( hasSharedRegionMapFile() ) {
506 if ( context.slideAndPackDylibs ) {
507 sharedRegionMakePrivate(context);
508 // remove underlying submap and block out 0x90000000 to 0xAFFFFFFF
509 vm_address_t addr = (vm_address_t)0x90000000;
510 vm_deallocate(mach_task_self(), addr, 0x20000000);
511 vm_allocate(mach_task_self(), &addr, 0x20000000, false);
512 sSharedRegionState = kSharedRegionMapFilePrivateMMapState;
513 }
514 else if ( context.sharedRegionMode == kUsePrivateSharedRegion ) {
515 sharedRegionMakePrivate(context);
516 sSharedRegionState = kSharedRegionMapFilePrivateState;
517 }
518 else if ( context.sharedRegionMode == kDontUseSharedRegion ) {
519 sSharedRegionState = kSharedRegionMapFilePrivateOutsideState;
520 }
521 else {
522 sSharedRegionState = kSharedRegionMapFileState;
523 }
524 }
525 else {
526 sSharedRegionState = kSharedRegionLoadFileState;
527 }
528 }
529
530 if ( kSharedRegionLoadFileState == sSharedRegionState ) {
531 if ( 0 != sharedRegionLoadFile(fd, offsetInFat, lenInFat, fileLen, context) ) {
532 sSharedRegionState = kSharedRegionMapFilePrivateOutsideState;
533 }
534 }
535 else
536 if ( kSharedRegionMapFileState == sSharedRegionState ) {
537 if ( 0 != sharedRegionMapFile(fd, offsetInFat, lenInFat, fileLen, context) ) {
538 sharedRegionMakePrivate(context);
539 sSharedRegionState = kSharedRegionMapFilePrivateState;
540 }
541 }
542
543 if ( (kSharedRegionMapFilePrivateState == sSharedRegionState) || (kSharedRegionMapFilePrivateMMapState == sSharedRegionState) ) {
544 if ( 0 != sharedRegionMapFilePrivate(fd, offsetInFat, lenInFat, fileLen, context, (kSharedRegionMapFilePrivateMMapState == sSharedRegionState)) ) {
545 sSharedRegionState = kSharedRegionMapFilePrivateOutsideState;
546 }
547 }
548
549 if ( kSharedRegionMapFilePrivateOutsideState == sSharedRegionState ) {
550 if ( 0 != sharedRegionMapFilePrivateOutside(fd, offsetInFat, lenInFat, fileLen, context) ) {
551 throw "mapping error";
552 }
553 }
554 }
555
556 unsigned int
557 ImageLoaderMachO::getExtraZeroFillEntriesCount()
558 {
559 // calculate mapping entries
560 const unsigned int segmentCount = fSegments.size();
561 unsigned int extraZeroFillEntries = 0;
562 for(unsigned int i=0; i < segmentCount; ++i){
563 Segment* seg = fSegments[i];
564 if ( seg->hasTrailingZeroFill() )
565 ++extraZeroFillEntries;
566 }
567
568 return extraZeroFillEntries;
569 }
570
571 void
572 ImageLoaderMachO::initMappingTable(uint64_t offsetInFat,
573 _shared_region_mapping_np *mappingTable)
574 {
575 unsigned int segmentCount = fSegments.size();
576 for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
577 Segment* seg = fSegments[segIndex];
578 _shared_region_mapping_np* entry = &mappingTable[entryIndex];
579 entry->address = seg->getActualLoadAddress();
580 entry->size = seg->getFileSize();
581 entry->file_offset = seg->getFileOffset() + offsetInFat;
582 entry->init_prot = VM_PROT_NONE;
583 if ( !seg->unaccessible() ) {
584 if ( seg->executable() )
585 entry->init_prot |= VM_PROT_EXECUTE;
586 if ( seg->readable() )
587 entry->init_prot |= VM_PROT_READ;
588 if ( seg->writeable() )
589 entry->init_prot |= VM_PROT_WRITE | VM_PROT_COW;
590 }
591 entry->max_prot = entry->init_prot;
592 if ( seg->hasTrailingZeroFill() ) {
593 _shared_region_mapping_np* zfentry = &mappingTable[++entryIndex];
594 zfentry->address = entry->address + seg->getFileSize();
595 zfentry->size = seg->getSize() - seg->getFileSize();
596 zfentry->file_offset = 0;
597 zfentry->init_prot = entry->init_prot | VM_PROT_COW | VM_PROT_ZF;
598 zfentry->max_prot = zfentry->init_prot;
599 }
600 }
601 }
602
603 int
604 ImageLoaderMachO::sharedRegionMakePrivate(const LinkContext& context)
605 {
606 if ( context.verboseMapping )
607 fprintf(stderr, "dyld: making shared regions private\n");
608
609 // shared mapping failed, so make private copy of shared region and try mapping private
610 RegionsVector allRegions;
611 context.getAllMappedRegions(allRegions);
612 std::vector<_shared_region_range_np> splitSegRegions;
613 const unsigned int allRegiontCount = allRegions.size();
614 for(unsigned int i=0; i < allRegiontCount; ++i){
615 MappedRegion region = allRegions[i];
616 uint8_t highByte = region.address >> 28;
617 if ( (highByte == 9) || (highByte == 0xA) ) {
618 _shared_region_range_np splitRegion;
619 splitRegion.address = region.address;
620 splitRegion.size = region.size;
621 splitSegRegions.push_back(splitRegion);
622 }
623 }
624 int result = _shared_region_make_private_np(splitSegRegions.size(), &splitSegRegions[0]);
625 // notify gdb or other lurkers that this process is no longer using the shared region
626 dyld_all_image_infos.processDetachedFromSharedRegion = true;
627 return result;
628 }
629
630 int
631 ImageLoaderMachO::sharedRegionMapFile(int fd,
632 uint64_t offsetInFat,
633 uint64_t lenInFat,
634 uint64_t fileLen,
635 const LinkContext& context)
636 {
637 // build table of segments to map
638 const unsigned int segmentCount = fSegments.size();
639 const unsigned int extraZeroFillEntries = getExtraZeroFillEntriesCount();
640 const unsigned int mappingTableCount = segmentCount+extraZeroFillEntries;
641 _shared_region_mapping_np mappingTable[mappingTableCount];
642 initMappingTable(offsetInFat, mappingTable);
643 // uint64_t slide;
644 uint64_t *slidep = NULL;
645
646 // try to map it in shared
647 int r = _shared_region_map_file_np(fd, mappingTableCount, mappingTable, slidep);
648 if ( 0 == r ) {
649 if(NULL != slidep && 0 != *slidep) {
650 // update with actual load addresses
651 }
652 if ( context.verboseMapping ) {
653 fprintf(stderr, "dyld: Mapping split-seg shared %s\n", this->getPath());
654 for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
655 Segment* seg = fSegments[segIndex];
656 const _shared_region_mapping_np* entry = &mappingTable[entryIndex];
657 if ( (entry->init_prot & VM_PROT_ZF) == 0 )
658 fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
659 seg->getName(), seg->getActualLoadAddress(), seg->getActualLoadAddress()+seg->getFileSize()-1);
660 if ( entryIndex < (mappingTableCount-1) ) {
661 const _shared_region_mapping_np* nextEntry = &mappingTable[entryIndex+1];
662 if ( (nextEntry->init_prot & VM_PROT_ZF) != 0 ) {
663 uint64_t segOffset = nextEntry->address - entry->address;
664 fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
665 seg->getName(), (uintptr_t)(seg->getActualLoadAddress() + segOffset), (uintptr_t)(seg->getActualLoadAddress() + segOffset + nextEntry->size - 1));
666 ++entryIndex;
667 }
668 }
669 }
670 }
671 }
672 return r;
673 }
674
675
676 int
677 ImageLoaderMachO::sharedRegionMapFilePrivate(int fd,
678 uint64_t offsetInFat,
679 uint64_t lenInFat,
680 uint64_t fileLen,
681 const LinkContext& context,
682 bool usemmap)
683 {
684 const unsigned int segmentCount = fSegments.size();
685
686 // adjust base address of segments to pack next to last dylib
687 if ( context.slideAndPackDylibs ) {
688 uintptr_t lowestReadOnly = (uintptr_t)(-1);
689 uintptr_t lowestWritable = (uintptr_t)(-1);
690 for(unsigned int segIndex=0; segIndex < segmentCount; ++segIndex){
691 Segment* seg = fSegments[segIndex];
692 uintptr_t segEnd = seg->getActualLoadAddress();
693 if ( seg->writeable() ) {
694 if ( segEnd < lowestWritable )
695 lowestWritable = segEnd;
696 }
697 else {
698 if ( segEnd < lowestReadOnly )
699 lowestReadOnly = segEnd;
700 }
701 }
702 uintptr_t baseAddress;
703 if ( lowestWritable - 256*1024*1024 < lowestReadOnly )
704 baseAddress = lowestWritable - 256*1024*1024;
705 else
706 baseAddress = lowestReadOnly;
707 // record that we want dylb slid to fgNextSplitSegAddress
708 this->setSlide(fgNextSplitSegAddress - baseAddress);
709 }
710
711 // build table of segments to map
712 const unsigned int extraZeroFillEntries = getExtraZeroFillEntriesCount();
713 const unsigned int mappingTableCount = segmentCount+extraZeroFillEntries;
714 _shared_region_mapping_np mappingTable[mappingTableCount];
715 initMappingTable(offsetInFat, mappingTable);
716 uint64_t slide = 0;
717
718 // try map it in privately (don't allow sliding if we pre-calculated the load address to pack dylibs)
719 int r;
720 if ( usemmap )
721 r = _shared_region_map_file_with_mmap(fd, mappingTableCount, mappingTable);
722 else
723 r = _shared_region_map_file_np(fd, mappingTableCount, mappingTable, context.slideAndPackDylibs ? NULL : &slide);
724 if ( 0 == r ) {
725 if ( 0 != slide ) {
726 slide = (slide) & (-4096); // round down to page boundary
727 this->setSlide(slide);
728 }
729 if ( context.verboseMapping ) {
730 if ( slide == 0 )
731 fprintf(stderr, "dyld: Mapping split-seg un-shared %s\n", this->getPath());
732 else
733 fprintf(stderr, "dyld: Mapping split-seg un-shared slid by 0x%08llX %s\n", slide, this->getPath());
734 for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
735 Segment* seg = fSegments[segIndex];
736 const _shared_region_mapping_np* entry = &mappingTable[entryIndex];
737 if ( (entry->init_prot & VM_PROT_ZF) == 0 )
738 fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
739 seg->getName(), seg->getActualLoadAddress(), seg->getActualLoadAddress()+seg->getFileSize()-1);
740 if ( entryIndex < (mappingTableCount-1) ) {
741 const _shared_region_mapping_np* nextEntry = &mappingTable[entryIndex+1];
742 if ( (nextEntry->init_prot & VM_PROT_ZF) != 0 ) {
743 uint64_t segOffset = nextEntry->address - entry->address;
744 fprintf(stderr, "%18s at 0x%08lX->0x%08lX (zerofill)\n",
745 seg->getName(), (uintptr_t)(seg->getActualLoadAddress() + segOffset), (uintptr_t)(seg->getActualLoadAddress() + segOffset + nextEntry->size - 1));
746 ++entryIndex;
747 }
748 }
749 }
750 }
751 if ( context.slideAndPackDylibs ) {
752 // calculate where next split-seg dylib can load
753 uintptr_t largestReadOnly = 0;
754 uintptr_t largestWritable = 0;
755 for (unsigned int segIndex=0; segIndex < segmentCount; ++segIndex) {
756 Segment* seg = fSegments[segIndex];
757 uintptr_t segEnd = seg->getActualLoadAddress()+seg->getSize();
758 segEnd = (segEnd+4095) & (-4096); // page align
759 if ( seg->writeable() ) {
760 if ( segEnd > largestWritable )
761 largestWritable = segEnd;
762 }
763 else {
764 if ( segEnd > largestReadOnly )
765 largestReadOnly = segEnd;
766 }
767 }
768 if ( largestWritable - 256*1024*1024 > largestReadOnly )
769 fgNextSplitSegAddress = largestWritable - 256*1024*1024;
770 else
771 fgNextSplitSegAddress = largestReadOnly;
772 }
773 }
774 if ( context.slideAndPackDylibs && (r != 0) )
775 throwf("can't rebase split-seg dylib %s because shared_region_map_file_np() returned %d", this->getPath(), r);
776
777 return r;
778 }
779
780
781 int
782 ImageLoaderMachO::sharedRegionLoadFile(int fd, uint64_t offsetInFat, uint64_t lenInFat, uint64_t fileLen, const LinkContext& context)
783 {
784
785 // map in split segment file at random address, then tell kernel to share it
786 void* loadAddress = 0;
787 loadAddress = mmap(NULL, fileLen, PROT_READ, MAP_FILE, fd, 0);
788 if ( loadAddress == ((void*)(-1)) )
789 throw "mmap error";
790
791 // calculate mapping entries
792 const unsigned int segmentCount = fSegments.size();
793 unsigned int extraZeroFillEntries = getExtraZeroFillEntriesCount();
794
795 // build table of segments to map
796 const unsigned int mappingTableCount = segmentCount+extraZeroFillEntries;
797 const uintptr_t baseAddress = fSegments[0]->getPreferredLoadAddress();
798 sf_mapping mappingTable[mappingTableCount];
799 initMappingTable(offsetInFat, mappingTable, baseAddress);
800
801
802 // use load_shared_file() to map all segments at once
803 int flags = 0; // might need to set NEW_LOCAL_SHARED_REGIONS on first use
804 static bool firstTime = true;
805 if ( firstTime ) {
806 // when NEW_LOCAL_SHARED_REGIONS bit is set, this process will get is own shared region
807 // this is used by Xcode to prevent development libraries from polluting the global shared segment
808 if ( context.sharedRegionMode == kUsePrivateSharedRegion )
809 flags |= NEW_LOCAL_SHARED_REGIONS;
810 firstTime = false;
811 }
812
813 caddr_t base_address = (caddr_t)baseAddress;
814 kern_return_t r;
815 r = load_shared_file( (char*)fPath, // path of file to map shared
816 (char*)loadAddress, // beginning of local copy of sharable pages in file
817 fileLen, // end of shareable pages in file
818 &base_address, // beginning of address range to map
819 mappingTableCount, // number of entres in array of sf_mapping
820 mappingTable, // the array of sf_mapping
821 &flags); // in/out flags
822 if ( 0 != r ) {
823 // try again but tell kernel it is ok to slide
824 flags |= ALTERNATE_LOAD_SITE;
825 r = load_shared_file((char*)fPath,(char*)loadAddress, fileLen, &base_address,
826 mappingTableCount, mappingTable, &flags);
827 }
828
829 // unmap file from random address now that they are (hopefully) mapped into the shared region
830 munmap(loadAddress, fileLen);
831
832 if ( 0 == r ) {
833 if ( base_address != (caddr_t)baseAddress )
834 this->setSlide((uintptr_t)base_address - baseAddress);
835 if ( context.verboseMapping ) {
836 if ( base_address != (caddr_t)baseAddress )
837 fprintf(stderr, "dyld: Mapping split-seg load_shared_alt_region %s\n", this->getPath());
838 else
839 fprintf(stderr, "dyld: Mapping split-seg load_shared %s\n", this->getPath());
840 for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
841 Segment* seg = fSegments[segIndex];
842 const sf_mapping* entry = &mappingTable[entryIndex];
843 if ( (entry->protection & VM_PROT_ZF) == 0 )
844 fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
845 seg->getName(), seg->getActualLoadAddress(), seg->getActualLoadAddress()+seg->getFileSize()-1);
846 if ( entryIndex < (mappingTableCount-1) ) {
847 const sf_mapping* nextEntry = &mappingTable[entryIndex+1];
848 if ( (nextEntry->protection & VM_PROT_ZF) != 0 ) {
849 fprintf(stderr, "%18s at 0x%08lX->0x%08lX\n",
850 seg->getName(), (uintptr_t)(nextEntry->mapping_offset + base_address), (uintptr_t)(nextEntry->mapping_offset + base_address + nextEntry->size - 1));
851 ++entryIndex;
852 }
853 }
854 }
855 }
856 }
857 return r;
858 }
859 void
860 ImageLoaderMachO::initMappingTable(uint64_t offsetInFat,
861 sf_mapping *mappingTable,
862 uintptr_t baseAddress)
863 {
864 unsigned int segmentCount = fSegments.size();
865 for(unsigned int segIndex=0,entryIndex=0; segIndex < segmentCount; ++segIndex, ++entryIndex){
866 Segment* seg = fSegments[segIndex];
867 sf_mapping* entry = &mappingTable[entryIndex];
868 entry->mapping_offset = seg->getPreferredLoadAddress() - baseAddress;
869 entry->size = seg->getFileSize();
870 entry->file_offset = seg->getFileOffset() + offsetInFat;
871 entry->protection = VM_PROT_NONE;
872 if ( !seg->unaccessible() ) {
873 if ( seg->executable() )
874 entry->protection |= VM_PROT_EXECUTE;
875 if ( seg->readable() )
876 entry->protection |= VM_PROT_READ;
877 if ( seg->writeable() )
878 entry->protection |= VM_PROT_WRITE | VM_PROT_COW;
879 }
880
881 entry->cksum = 0;
882 if ( seg->hasTrailingZeroFill() ) {
883 sf_mapping* zfentry = &mappingTable[++entryIndex];
884 zfentry->mapping_offset = entry->mapping_offset + seg->getFileSize();
885 zfentry->size = seg->getSize() - seg->getFileSize();
886 zfentry->file_offset = 0;
887 zfentry->protection = entry->protection | VM_PROT_COW | VM_PROT_ZF;
888 zfentry->cksum = 0;
889 }
890 }
891 }
892
893 #endif // !__LP64__ split segs not supported for 64-bits
894
895
896 void ImageLoaderMachO::setSlide(intptr_t slide)
897 {
898 fSlide = slide;
899 }
900
901 void ImageLoaderMachO::parseLoadCmds()
902 {
903 // now that segments are mapped in, get real fMachOData, fLinkEditBase, and fSlide
904 const unsigned int segmentCount = fSegments.size();
905 for(unsigned int i=0; i < segmentCount; ++i){
906 Segment* seg = fSegments[i];
907 // set up pointer to __LINKEDIT segment
908 if ( strcmp(seg->getName(),"__LINKEDIT") == 0 )
909 fLinkEditBase = (uint8_t*)(seg->getActualLoadAddress() - seg->getFileOffset());
910 // __TEXT segment always starts at beginning of file and contains mach_header and load commands
911 if ( strcmp(seg->getName(),"__TEXT") == 0 ) {
912 if ( seg->hasFixUps() )
913 fTextSegmentWithFixups = (SegmentMachO*)seg;
914 }
915 // some segment always starts at beginning of file and contains mach_header and load commands
916 if ( (seg->getFileOffset() == 0) && (seg->getFileSize() != 0) ) {
917 fMachOData = (uint8_t*)(seg->getActualLoadAddress());
918 }
919 }
920
921 // keep count of prebound images with weak exports
922 if ( this->hasCoalescedExports() )
923 ++fgCountOfImagesWithWeakExports;
924
925 // walk load commands (mapped in at start of __TEXT segment)
926 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
927 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
928 const struct load_command* cmd = cmds;
929 for (uint32_t i = 0; i < cmd_count; ++i) {
930 switch (cmd->cmd) {
931 case LC_SYMTAB:
932 {
933 const struct symtab_command* symtab = (struct symtab_command*)cmd;
934 fStrings = (const char*)&fLinkEditBase[symtab->stroff];
935 fSymbolTable = (struct macho_nlist*)(&fLinkEditBase[symtab->symoff]);
936 }
937 break;
938 case LC_DYSYMTAB:
939 fDynamicInfo = (struct dysymtab_command*)cmd;
940 break;
941 case LC_SUB_UMBRELLA:
942 fHasSubUmbrella = true;
943 break;
944 case LC_SUB_FRAMEWORK:
945 {
946 const struct sub_framework_command* subf = (struct sub_framework_command*)cmd;
947 fReExportThruFramework = (char*)cmd + subf->umbrella.offset;
948 }
949 break;
950 case LC_SUB_LIBRARY:
951 fHasSubLibraries = true;
952 break;
953 case LC_ROUTINES_COMMAND:
954 fDashInit = (struct macho_routines_command*)cmd;
955 break;
956 case LC_SEGMENT_COMMAND:
957 {
958 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
959 const bool isDataSeg = (strcmp(seg->segname, "__DATA") == 0);
960 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
961 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
962 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
963 const uint8_t type = sect->flags & SECTION_TYPE;
964 if ( type == S_MOD_INIT_FUNC_POINTERS )
965 fModInitSection = sect;
966 else if ( type == S_MOD_TERM_FUNC_POINTERS )
967 fModTermSection = sect;
968 else if ( isDataSeg && (strcmp(sect->sectname, "__dyld") == 0) ) {
969 fDATAdyld = sect;
970 }
971 else if ( isDataSeg && (strcmp(sect->sectname, "__image_notify") == 0) )
972 fImageNotifySection = sect;
973 }
974 }
975 break;
976 case LC_TWOLEVEL_HINTS:
977 fTwoLevelHints = (struct twolevel_hints_command*)cmd;
978 break;
979 case LC_ID_DYLIB:
980 {
981 fDylibID = (struct dylib_command*)cmd;
982 }
983 break;
984 case LC_LOAD_WEAK_DYLIB:
985 // do nothing, just prevent LC_REQ_DYLD exception from occuring
986 break;
987 default:
988 if ( (cmd->cmd & LC_REQ_DYLD) != 0 )
989 throwf("unknown required load command 0x%08X", cmd->cmd);
990 }
991 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
992 }
993 }
994
995
996
997
998 const char* ImageLoaderMachO::getInstallPath() const
999 {
1000 if ( fDylibID != NULL ) {
1001 return (char*)fDylibID + fDylibID->dylib.name.offset;
1002 }
1003 return NULL;
1004 }
1005
1006 // test if this image is re-exported through parent (the image that loaded this one)
1007 bool ImageLoaderMachO::isSubframeworkOf(const LinkContext& context, const ImageLoader* parent) const
1008 {
1009 if ( fReExportThruFramework != NULL ) {
1010 // need to match LC_SUB_FRAMEWORK string against the leaf name of the install location of parent...
1011 const char* parentInstallPath = parent->getInstallPath();
1012 if ( parentInstallPath != NULL ) {
1013 const char* lastSlash = strrchr(parentInstallPath, '/');
1014 if ( lastSlash != NULL ) {
1015 if ( strcmp(&lastSlash[1], fReExportThruFramework) == 0 )
1016 return true;
1017 if ( context.imageSuffix != NULL ) {
1018 // when DYLD_IMAGE_SUFFIX is used, lastSlash string needs imageSuffix removed from end
1019 char reexportAndSuffix[strlen(context.imageSuffix)+strlen(fReExportThruFramework)+1];
1020 strcpy(reexportAndSuffix, fReExportThruFramework);
1021 strcat(reexportAndSuffix, context.imageSuffix);
1022 if ( strcmp(&lastSlash[1], reexportAndSuffix) == 0 )
1023 return true;
1024 }
1025 }
1026 }
1027 }
1028 return false;
1029 }
1030
1031 // test if child is re-exported
1032 bool ImageLoaderMachO::hasSubLibrary(const LinkContext& context, const ImageLoader* child) const
1033 {
1034 if ( fHasSubLibraries ) {
1035 // need to match LC_SUB_LIBRARY string against the leaf name (without extension) of the install location of child...
1036 const char* childInstallPath = child->getInstallPath();
1037 if ( childInstallPath != NULL ) {
1038 const char* lastSlash = strrchr(childInstallPath, '/');
1039 if ( lastSlash != NULL ) {
1040 const char* firstDot = strchr(lastSlash, '.');
1041 int len;
1042 if ( firstDot == NULL )
1043 len = strlen(lastSlash);
1044 else
1045 len = firstDot-lastSlash-1;
1046 char childLeafName[len+1];
1047 strncpy(childLeafName, &lastSlash[1], len);
1048 childLeafName[len] = '\0';
1049 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1050 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1051 const struct load_command* cmd = cmds;
1052 for (uint32_t i = 0; i < cmd_count; ++i) {
1053 switch (cmd->cmd) {
1054 case LC_SUB_LIBRARY:
1055 {
1056 const struct sub_library_command* lib = (struct sub_library_command*)cmd;
1057 const char* aSubLibName = (char*)cmd + lib->sub_library.offset;
1058 if ( strcmp(aSubLibName, childLeafName) == 0 )
1059 return true;
1060 if ( context.imageSuffix != NULL ) {
1061 // when DYLD_IMAGE_SUFFIX is used, childLeafName string needs imageSuffix removed from end
1062 char aSubLibNameAndSuffix[strlen(context.imageSuffix)+strlen(aSubLibName)+1];
1063 strcpy(aSubLibNameAndSuffix, aSubLibName);
1064 strcat(aSubLibNameAndSuffix, context.imageSuffix);
1065 if ( strcmp(aSubLibNameAndSuffix, childLeafName) == 0 )
1066 return true;
1067 }
1068 }
1069 break;
1070 }
1071 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1072 }
1073 }
1074 }
1075 }
1076 if ( fHasSubUmbrella ) {
1077 // need to match LC_SUB_UMBRELLA string against the leaf name of install location of child...
1078 const char* childInstallPath = child->getInstallPath();
1079 if ( childInstallPath != NULL ) {
1080 const char* lastSlash = strrchr(childInstallPath, '/');
1081 if ( lastSlash != NULL ) {
1082 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1083 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1084 const struct load_command* cmd = cmds;
1085 for (uint32_t i = 0; i < cmd_count; ++i) {
1086 switch (cmd->cmd) {
1087 case LC_SUB_UMBRELLA:
1088 {
1089 const struct sub_umbrella_command* um = (struct sub_umbrella_command*)cmd;
1090 const char* aSubUmbrellaName = (char*)cmd + um->sub_umbrella.offset;
1091 if ( strcmp(aSubUmbrellaName, &lastSlash[1]) == 0 )
1092 return true;
1093 if ( context.imageSuffix != NULL ) {
1094 // when DYLD_IMAGE_SUFFIX is used, lastSlash string needs imageSuffix removed from end
1095 char umbrellaAndSuffix[strlen(context.imageSuffix)+strlen(aSubUmbrellaName)+1];
1096 strcpy(umbrellaAndSuffix, aSubUmbrellaName);
1097 strcat(umbrellaAndSuffix, context.imageSuffix);
1098 if ( strcmp(umbrellaAndSuffix, &lastSlash[1]) == 0 )
1099 return true;
1100 }
1101 }
1102 break;
1103 }
1104 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1105 }
1106 }
1107 }
1108 }
1109 return false;
1110 }
1111
1112
1113 void* ImageLoaderMachO::getMain() const
1114 {
1115 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1116 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1117 const struct load_command* cmd = cmds;
1118 for (unsigned long i = 0; i < cmd_count; ++i) {
1119 switch (cmd->cmd) {
1120 case LC_UNIXTHREAD:
1121 {
1122 #if __ppc__
1123 const ppc_thread_state_t* registers = (ppc_thread_state_t*)(((char*)cmd) + 16);
1124 return (void*)registers->srr0;
1125 #elif __ppc64__
1126 const ppc_thread_state64_t* registers = (ppc_thread_state64_t*)(((char*)cmd) + 16);
1127 return (void*)registers->srr0;
1128 #elif __i386__
1129 const i386_thread_state_t* registers = (i386_thread_state_t*)(((char*)cmd) + 16);
1130 return (void*)registers->eip;
1131 #elif __x86_64__
1132 const x86_thread_state64_t* registers = (x86_thread_state64_t*)(((char*)cmd) + 16);
1133 return (void*)registers->rip;
1134 #else
1135 #warning need processor specific code
1136 #endif
1137 }
1138 break;
1139 }
1140 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1141 }
1142 return NULL;
1143 }
1144
1145
1146 uint32_t ImageLoaderMachO::doGetDependentLibraryCount()
1147 {
1148 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1149 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1150 uint32_t count = 0;
1151 const struct load_command* cmd = cmds;
1152 for (unsigned long i = 0; i < cmd_count; ++i) {
1153 switch (cmd->cmd) {
1154 case LC_LOAD_DYLIB:
1155 case LC_LOAD_WEAK_DYLIB:
1156 ++count;
1157 break;
1158 }
1159 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1160 }
1161 return count;
1162 }
1163
1164 void ImageLoaderMachO::doGetDependentLibraries(DependentLibrary libs[])
1165 {
1166 uint32_t index = 0;
1167 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1168 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1169 const struct load_command* cmd = cmds;
1170 for (unsigned long i = 0; i < cmd_count; ++i) {
1171 switch (cmd->cmd) {
1172 case LC_LOAD_DYLIB:
1173 case LC_LOAD_WEAK_DYLIB:
1174 {
1175 const struct dylib_command* dylib = (struct dylib_command*)cmd;
1176 DependentLibrary* lib = &libs[index++];
1177 lib->name = (char*)cmd + dylib->dylib.name.offset;
1178 //lib->name = strdup((char*)cmd + dylib->dylib.name.offset);
1179 lib->image = NULL;
1180 lib->info.checksum = dylib->dylib.timestamp;
1181 lib->info.minVersion = dylib->dylib.compatibility_version;
1182 lib->info.maxVersion = dylib->dylib.current_version;
1183 lib->required = (cmd->cmd == LC_LOAD_DYLIB);
1184 lib->checksumMatches = false;
1185 lib->isReExported = false;
1186 }
1187 break;
1188 }
1189 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1190 }
1191 }
1192
1193 ImageLoader::LibraryInfo ImageLoaderMachO::doGetLibraryInfo()
1194 {
1195 LibraryInfo info;
1196 if ( fDylibID != NULL ) {
1197 info.minVersion = fDylibID->dylib.compatibility_version;
1198 info.maxVersion = fDylibID->dylib.current_version;
1199 info.checksum = fDylibID->dylib.timestamp;
1200 }
1201 else {
1202 info.minVersion = 0;
1203 info.maxVersion = 0;
1204 info.checksum = 0;
1205 }
1206 return info;
1207 }
1208
1209 uintptr_t ImageLoaderMachO::getFirstWritableSegmentAddress()
1210 {
1211 // in split segment libraries r_address is offset from first writable segment
1212 for (std::vector<class Segment*>::iterator it=fSegments.begin(); it != fSegments.end(); ++it) {
1213 if ( (*it)->writeable() ) {
1214 return (*it)->getActualLoadAddress();
1215 }
1216 }
1217 throw "no writable segment";
1218 }
1219
1220 uintptr_t ImageLoaderMachO::getRelocBase()
1221 {
1222 #if __x86_64__
1223 // r_address is offset from first writable segment
1224 return getFirstWritableSegmentAddress();
1225 #endif
1226 #if __ppc__ || __i386__
1227 if ( fIsSplitSeg ) {
1228 // in split segment libraries r_address is offset from first writable segment
1229 return getFirstWritableSegmentAddress();
1230 }
1231 #endif
1232
1233 // in non-split segment libraries r_address is offset from first segment
1234 return fSegments[0]->getActualLoadAddress();
1235 }
1236
1237 #if __ppc__
1238 static inline void otherRelocsPPC(uintptr_t* locationToFix, uint8_t relocationType, uint16_t otherHalf, uintptr_t slide)
1239 {
1240 // low 16 bits of 32-bit ppc instructions need fixing
1241 struct ppcInstruction { uint16_t opcode; int16_t immediateValue; };
1242 ppcInstruction* instruction = (ppcInstruction*)locationToFix;
1243 //uint32_t before = *((uint32_t*)locationToFix);
1244 switch ( relocationType )
1245 {
1246 case PPC_RELOC_LO16:
1247 instruction->immediateValue = ((otherHalf << 16) | instruction->immediateValue) + slide;
1248 break;
1249 case PPC_RELOC_HI16:
1250 instruction->immediateValue = ((((instruction->immediateValue << 16) | otherHalf) + slide) >> 16);
1251 break;
1252 case PPC_RELOC_HA16:
1253 int16_t signedOtherHalf = (int16_t)(otherHalf & 0xffff);
1254 uint32_t temp = (instruction->immediateValue << 16) + signedOtherHalf + slide;
1255 if ( (temp & 0x00008000) != 0 )
1256 temp += 0x00008000;
1257 instruction->immediateValue = temp >> 16;
1258 }
1259 //uint32_t after = *((uint32_t*)locationToFix);
1260 //fprintf(stderr, "dyld: ppc fixup %0p type %d from 0x%08X to 0x%08X\n", locationToFix, relocationType, before, after);
1261 }
1262 #endif
1263
1264 #if __ppc__ || __i386__
1265 void ImageLoaderMachO::resetPreboundLazyPointers(const LinkContext& context, uintptr_t relocBase)
1266 {
1267 // loop through all local (internal) relocation records looking for pre-bound-lazy-pointer values
1268 register const uintptr_t slide = this->fSlide;
1269 const relocation_info* const relocsStart = (struct relocation_info*)(&fLinkEditBase[fDynamicInfo->locreloff]);
1270 const relocation_info* const relocsEnd = &relocsStart[fDynamicInfo->nlocrel];
1271 for (const relocation_info* reloc=relocsStart; reloc < relocsEnd; ++reloc) {
1272 if ( (reloc->r_address & R_SCATTERED) != 0 ) {
1273 const struct scattered_relocation_info* sreloc = (struct scattered_relocation_info*)reloc;
1274 if (sreloc->r_length == RELOC_SIZE) {
1275 uintptr_t* locationToFix = (uintptr_t*)(sreloc->r_address + relocBase);
1276 switch(sreloc->r_type) {
1277 #if __ppc__
1278 case PPC_RELOC_PB_LA_PTR:
1279 *locationToFix = sreloc->r_value + slide;
1280 break;
1281 #endif
1282 #if __i386__
1283 case GENERIC_RELOC_PB_LA_PTR:
1284 *locationToFix = sreloc->r_value + slide;
1285 break;
1286 #endif
1287 }
1288 }
1289 }
1290 }
1291 }
1292 #endif
1293
1294 void ImageLoaderMachO::doRebase(const LinkContext& context)
1295 {
1296 // if prebound and loaded at prebound address, then no need to rebase
1297 if ( this->usablePrebinding(context) ) {
1298 // skip rebasing cause prebound and prebinding not disabled
1299 ++fgImagesWithUsedPrebinding; // bump totals for statistics
1300 return;
1301 }
1302
1303 // <rdar://problem/5146059> update_prebinding fails if a prebound dylib depends on a non-prebound dylib
1304 // In the unusual case that we find a prebound dylib dependent on un-prebound dylib and we are running
1305 // update_prebinding, we want the link of the prebound dylib to fail so that it will be excluded from
1306 // the list of dylibs to be re-written.
1307 if ( context.prebinding && !this->isPrebindable() )
1308 throwf("dylib not prebound: %s", this->getPath());
1309
1310 // print why prebinding was not used
1311 if ( context.verbosePrebinding ) {
1312 if ( !this->isPrebindable() ) {
1313 fprintf(stderr, "dyld: image not prebound, so could not use prebinding in %s\n", this->getPath());
1314 }
1315 else if ( fSlide != 0 ) {
1316 fprintf(stderr, "dyld: image slid, so could not use prebinding in %s\n", this->getPath());
1317 }
1318 else if ( !this->allDependentLibrariesAsWhenPreBound() ) {
1319 fprintf(stderr, "dyld: dependent libraries changed, so could not use prebinding in %s\n", this->getPath());
1320 }
1321 else if ( !this->usesTwoLevelNameSpace() ){
1322 fprintf(stderr, "dyld: image uses flat-namespace so, parts of prebinding ignored %s\n", this->getPath());
1323 }
1324 else {
1325 fprintf(stderr, "dyld: environment variable disabled use of prebinding in %s\n", this->getPath());
1326 }
1327 }
1328
1329 // cache values that are used in the following loop
1330 const uintptr_t relocBase = this->getRelocBase();
1331 register const uintptr_t slide = this->fSlide;
1332
1333 #if __ppc__ || __i386__
1334 // if prebound and we got here, then prebinding is not valid, so reset all lazy pointers
1335 if ( this->isPrebindable() )
1336 this->resetPreboundLazyPointers(context, relocBase);
1337 #endif
1338
1339 // if loaded at preferred address, no rebasing necessary
1340 if ( slide == 0 )
1341 return;
1342
1343 // if there are __TEXT fixups, temporarily make __TEXT writable
1344 if ( fTextSegmentWithFixups != NULL )
1345 fTextSegmentWithFixups->tempWritable();
1346
1347 // loop through all local (internal) relocation records
1348 const relocation_info* const relocsStart = (struct relocation_info*)(&fLinkEditBase[fDynamicInfo->locreloff]);
1349 const relocation_info* const relocsEnd = &relocsStart[fDynamicInfo->nlocrel];
1350 for (const relocation_info* reloc=relocsStart; reloc < relocsEnd; ++reloc) {
1351 #if __x86_64__
1352 // only one kind of local relocation supported for x86_64
1353 if ( reloc->r_length != 3 )
1354 throw "bad local relocation length";
1355 if ( reloc->r_type != X86_64_RELOC_UNSIGNED )
1356 throw "unknown local relocation type";
1357 if ( reloc->r_pcrel != 0 )
1358 throw "bad local relocation pc_rel";
1359 if ( reloc->r_extern != 0 )
1360 throw "extern relocation found with local relocations";
1361 *((uintptr_t*)(reloc->r_address + relocBase)) += slide;
1362 #endif
1363 #if __ppc__ || __ppc64__ || __i386__
1364 if ( (reloc->r_address & R_SCATTERED) == 0 ) {
1365 if ( reloc->r_symbolnum == R_ABS ) {
1366 // ignore absolute relocations
1367 }
1368 else if (reloc->r_length == RELOC_SIZE) {
1369 switch(reloc->r_type) {
1370 case GENERIC_RELOC_VANILLA:
1371 *((uintptr_t*)(reloc->r_address + relocBase)) += slide;
1372 break;
1373 #if __ppc__
1374 case PPC_RELOC_HI16:
1375 case PPC_RELOC_LO16:
1376 case PPC_RELOC_HA16:
1377 // some tools leave object file relocations in linked images
1378 otherRelocsPPC((uintptr_t*)(reloc->r_address + relocBase), reloc->r_type, reloc[1].r_address, slide);
1379 ++reloc; // these relocations come in pairs, skip next
1380 break;
1381 #endif
1382 default:
1383 throw "unknown local relocation type";
1384 }
1385 }
1386 else {
1387 throw "bad local relocation length";
1388 }
1389 }
1390 else {
1391 const struct scattered_relocation_info* sreloc = (struct scattered_relocation_info*)reloc;
1392 if (sreloc->r_length == RELOC_SIZE) {
1393 uintptr_t* locationToFix = (uintptr_t*)(sreloc->r_address + relocBase);
1394 switch(sreloc->r_type) {
1395 case GENERIC_RELOC_VANILLA:
1396 *locationToFix += slide;
1397 break;
1398 #if __ppc__
1399 case PPC_RELOC_HI16:
1400 case PPC_RELOC_LO16:
1401 case PPC_RELOC_HA16:
1402 // Metrowerks compiler sometimes leaves object file relocations in linked images???
1403 ++reloc; // these relocations come in pairs, get next one
1404 otherRelocsPPC(locationToFix, sreloc->r_type, reloc->r_address, slide);
1405 break;
1406 #endif
1407 #if __ppc__
1408 case PPC_RELOC_PB_LA_PTR:
1409 // do nothing
1410 break;
1411 #elif __ppc64__
1412 case PPC_RELOC_PB_LA_PTR:
1413 // these should never exist in ppc64, but the first ld64 had a bug and created them
1414 *locationToFix = sreloc->r_value + slide;
1415 break;
1416 #elif __i386__
1417 case GENERIC_RELOC_PB_LA_PTR:
1418 // do nothing
1419 break;
1420 #endif
1421 default:
1422 throw "unknown local scattered relocation type";
1423 }
1424 }
1425 else {
1426 throw "bad local scattered relocation length";
1427 }
1428 }
1429 #endif
1430 }
1431
1432 // if there were __TEXT fixups, restore write protection
1433 if ( fTextSegmentWithFixups != NULL ) {
1434 fTextSegmentWithFixups->setPermissions();
1435 sys_icache_invalidate((void*)fTextSegmentWithFixups->getActualLoadAddress(), fTextSegmentWithFixups->getSize());
1436 }
1437
1438 // update stats
1439 fgTotalRebaseFixups += fDynamicInfo->nlocrel;
1440 }
1441
1442
1443 const struct macho_nlist* ImageLoaderMachO::binarySearchWithToc(const char* key, const char stringPool[], const struct macho_nlist symbols[],
1444 const struct dylib_table_of_contents toc[], uint32_t symbolCount, uint32_t hintIndex)
1445 {
1446 int32_t high = symbolCount-1;
1447 int32_t mid = hintIndex;
1448
1449 // handle out of range hint
1450 if ( mid >= (int32_t)symbolCount ) {
1451 mid = symbolCount/2;
1452 ++ImageLoaderMachO::fgUnhintedBinaryTreeSearchs;
1453 }
1454 else {
1455 ++ImageLoaderMachO::fgHintedBinaryTreeSearchs;
1456 }
1457
1458 for (int32_t low = 0; low <= high; mid = (low+high)/2) {
1459 const uint32_t index = toc[mid].symbol_index;
1460 const struct macho_nlist* pivot = &symbols[index];
1461 const char* pivotStr = &stringPool[pivot->n_un.n_strx];
1462 #if LINKEDIT_USAGE_DEBUG
1463 noteAccessedLinkEditAddress(&toc[mid]);
1464 noteAccessedLinkEditAddress(pivot);
1465 noteAccessedLinkEditAddress(pivotStr);
1466 #endif
1467 int cmp = astrcmp(key, pivotStr);
1468 if ( cmp == 0 )
1469 return pivot;
1470 if ( cmp > 0 ) {
1471 // key > pivot
1472 low = mid + 1;
1473 }
1474 else {
1475 // key < pivot
1476 high = mid - 1;
1477 }
1478 }
1479 return NULL;
1480 }
1481
1482 const struct macho_nlist* ImageLoaderMachO::binarySearch(const char* key, const char stringPool[], const struct macho_nlist symbols[], uint32_t symbolCount)
1483 {
1484 ++ImageLoaderMachO::fgUnhintedBinaryTreeSearchs;
1485 const struct macho_nlist* base = symbols;
1486 for (uint32_t n = symbolCount; n > 0; n /= 2) {
1487 const struct macho_nlist* pivot = &base[n/2];
1488 const char* pivotStr = &stringPool[pivot->n_un.n_strx];
1489 #if LINKEDIT_USAGE_DEBUG
1490 noteAccessedLinkEditAddress(pivot);
1491 noteAccessedLinkEditAddress(pivotStr);
1492 #endif
1493 int cmp = astrcmp(key, pivotStr);
1494 if ( cmp == 0 )
1495 return pivot;
1496 if ( cmp > 0 ) {
1497 // key > pivot
1498 // move base to symbol after pivot
1499 base = &pivot[1];
1500 --n;
1501 }
1502 else {
1503 // key < pivot
1504 // keep same base
1505 }
1506 }
1507 return NULL;
1508 }
1509
1510 const ImageLoader::Symbol* ImageLoaderMachO::findExportedSymbol(const char* name, const void* hint, bool searchReExports, ImageLoader** foundIn) const
1511 {
1512 const struct macho_nlist* sym = NULL;
1513 const struct twolevel_hint* theHint = (struct twolevel_hint*)hint;
1514 if ( fDynamicInfo->tocoff == 0 )
1515 sym = binarySearch(name, fStrings, &fSymbolTable[fDynamicInfo->iextdefsym], fDynamicInfo->nextdefsym);
1516 else {
1517 uint32_t start = fDynamicInfo->nextdefsym;
1518 if ( theHint != NULL )
1519 start = theHint->itoc;
1520 if ( (theHint == NULL) || (theHint->isub_image == 0) ) {
1521 sym = binarySearchWithToc(name, fStrings, fSymbolTable, (dylib_table_of_contents*)&fLinkEditBase[fDynamicInfo->tocoff],
1522 fDynamicInfo->ntoc, start);
1523 }
1524 }
1525 if ( sym != NULL ) {
1526 if ( foundIn != NULL )
1527 *foundIn = (ImageLoader*)this;
1528
1529 return (const Symbol*)sym;
1530 }
1531
1532 if ( searchReExports ) {
1533 // hint might tell us to try a particular subimage
1534 if ( (theHint != NULL) && (theHint->isub_image > 0) && (theHint->isub_image <= fLibrariesCount) ) {
1535 // isub_image is an index into a list that is sorted non-rexported images first
1536 uint32_t index = 0;
1537 ImageLoader* target = NULL;
1538 // pass one, only look at sub-frameworks
1539 for (uint32_t i=0; i < fLibrariesCount; ++i) {
1540 DependentLibrary& libInfo = fLibraries[i];
1541 if ( libInfo.isSubFramework && (libInfo.image != NULL)) {
1542 if ( ++index == theHint->isub_image ) {
1543 target = libInfo.image;
1544 break;
1545 }
1546 }
1547 }
1548 if (target != NULL) {
1549 // pass two, only look at non-sub-framework-reexports
1550 for (uint32_t i=0; i < fLibrariesCount; ++i) {
1551 DependentLibrary& libInfo = fLibraries[i];
1552 if ( libInfo.isReExported && !libInfo.isSubFramework && (libInfo.image != NULL) ) {
1553 if ( ++index == theHint->isub_image ) {
1554 target = libInfo.image;
1555 break;
1556 }
1557 }
1558 }
1559 }
1560 if (target != NULL) {
1561 const Symbol* result = target->findExportedSymbol(name, NULL, searchReExports, foundIn);
1562 if ( result != NULL )
1563 return result;
1564 }
1565 }
1566
1567 // hint failed, try all sub images
1568 // pass one, only look at sub-frameworks
1569 for(unsigned int i=0; i < fLibrariesCount; ++i){
1570 DependentLibrary& libInfo = fLibraries[i];
1571 if ( (libInfo.image != NULL) && libInfo.isSubFramework ) {
1572 const Symbol* result = libInfo.image->findExportedSymbol(name, NULL, searchReExports, foundIn);
1573 if ( result != NULL )
1574 return result;
1575 }
1576 }
1577 // pass two, only look at non-sub-framework-reexports
1578 for(unsigned int i=0; i < fLibrariesCount; ++i){
1579 DependentLibrary& libInfo = fLibraries[i];
1580 if ( (libInfo.image != NULL) && libInfo.isReExported && !libInfo.isSubFramework ) {
1581 const Symbol* result = libInfo.image->findExportedSymbol(name, NULL, searchReExports, foundIn);
1582 if ( result != NULL )
1583 return result;
1584 }
1585 }
1586 }
1587
1588 // last change: the hint is wrong (non-zero but actually in this image)
1589 if ( (theHint != NULL) && (theHint->isub_image != 0) ) {
1590 sym = binarySearchWithToc(name, fStrings, fSymbolTable, (dylib_table_of_contents*)&fLinkEditBase[fDynamicInfo->tocoff],
1591 fDynamicInfo->ntoc, fDynamicInfo->nextdefsym);
1592 if ( sym != NULL ) {
1593 if ( foundIn != NULL )
1594 *foundIn = (ImageLoader*)this;
1595 return (const Symbol*)sym;
1596 }
1597 }
1598
1599
1600 return NULL;
1601 }
1602
1603
1604 uintptr_t ImageLoaderMachO::getExportedSymbolAddress(const Symbol* sym) const
1605 {
1606 const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
1607 return nlistSym->n_value + fSlide;
1608 }
1609
1610 ImageLoader::DefinitionFlags ImageLoaderMachO::getExportedSymbolInfo(const Symbol* sym) const
1611 {
1612 const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
1613 if ( (nlistSym->n_desc & N_WEAK_DEF) != 0 )
1614 return kWeakDefinition;
1615 return kNoDefinitionOptions;
1616 }
1617
1618 const char* ImageLoaderMachO::getExportedSymbolName(const Symbol* sym) const
1619 {
1620 const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
1621 return &fStrings[nlistSym->n_un.n_strx];
1622 }
1623
1624 uint32_t ImageLoaderMachO::getExportedSymbolCount() const
1625 {
1626 return fDynamicInfo->nextdefsym;
1627 }
1628
1629
1630 const ImageLoader::Symbol* ImageLoaderMachO::getIndexedExportedSymbol(uint32_t index) const
1631 {
1632 if ( index < fDynamicInfo->nextdefsym ) {
1633 const struct macho_nlist* sym = &fSymbolTable[fDynamicInfo->iextdefsym + index];
1634 return (const ImageLoader::Symbol*)sym;
1635 }
1636 return NULL;
1637 }
1638
1639
1640 uint32_t ImageLoaderMachO::getImportedSymbolCount() const
1641 {
1642 return fDynamicInfo->nundefsym;
1643 }
1644
1645
1646 const ImageLoader::Symbol* ImageLoaderMachO::getIndexedImportedSymbol(uint32_t index) const
1647 {
1648 if ( index < fDynamicInfo->nundefsym ) {
1649 const struct macho_nlist* sym = &fSymbolTable[fDynamicInfo->iundefsym + index];
1650 return (const ImageLoader::Symbol*)sym;
1651 }
1652 return NULL;
1653 }
1654
1655
1656 ImageLoader::ReferenceFlags ImageLoaderMachO::geImportedSymbolInfo(const ImageLoader::Symbol* sym) const
1657 {
1658 const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
1659 ImageLoader::ReferenceFlags flags = kNoReferenceOptions;
1660 if ( ((nlistSym->n_type & N_TYPE) == N_UNDF) && (nlistSym->n_value != 0) )
1661 flags |= ImageLoader::kTentativeDefinition;
1662 if ( (nlistSym->n_desc & N_WEAK_REF) != 0 )
1663 flags |= ImageLoader::kWeakReference;
1664 return flags;
1665 }
1666
1667
1668 const char* ImageLoaderMachO::getImportedSymbolName(const ImageLoader::Symbol* sym) const
1669 {
1670 const struct macho_nlist* nlistSym = (const struct macho_nlist*)sym;
1671 return &fStrings[nlistSym->n_un.n_strx];
1672 }
1673
1674
1675 bool ImageLoaderMachO::getSectionContent(const char* segmentName, const char* sectionName, void** start, size_t* length)
1676 {
1677 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1678 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1679 const struct load_command* cmd = cmds;
1680 for (uint32_t i = 0; i < cmd_count; ++i) {
1681 switch (cmd->cmd) {
1682 case LC_SEGMENT_COMMAND:
1683 {
1684 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
1685 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
1686 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
1687 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
1688 if ( (strcmp(sect->segname, segmentName) == 0) && (strcmp(sect->sectname, sectionName) == 0) ) {
1689 *start = (uintptr_t*)(sect->addr + fSlide);
1690 *length = sect->size;
1691 return true;
1692 }
1693 }
1694 }
1695 break;
1696 }
1697 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1698 }
1699 return false;
1700 }
1701
1702
1703 bool ImageLoaderMachO::findSection(const void* imageInterior, const char** segmentName, const char** sectionName, size_t* sectionOffset)
1704 {
1705 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1706 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1707 const struct load_command* cmd = cmds;
1708 const uintptr_t unslidInteriorAddress = (uintptr_t)imageInterior - this->getSlide();
1709 for (uint32_t i = 0; i < cmd_count; ++i) {
1710 switch (cmd->cmd) {
1711 case LC_SEGMENT_COMMAND:
1712 {
1713 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
1714 if ( (unslidInteriorAddress >= seg->vmaddr) && (unslidInteriorAddress < (seg->vmaddr+seg->vmsize)) ) {
1715 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
1716 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
1717 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
1718 if ((sect->addr <= unslidInteriorAddress) && (unslidInteriorAddress < (sect->addr+sect->size))) {
1719 if ( segmentName != NULL )
1720 *segmentName = sect->segname;
1721 if ( sectionName != NULL )
1722 *sectionName = sect->sectname;
1723 if ( sectionOffset != NULL )
1724 *sectionOffset = unslidInteriorAddress - sect->addr;
1725 return true;
1726 }
1727 }
1728 }
1729 }
1730 break;
1731 }
1732 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1733 }
1734 return false;
1735 }
1736
1737
1738 bool ImageLoaderMachO::symbolRequiresCoalescing(const struct macho_nlist* symbol)
1739 {
1740 // if a define and weak ==> coalesced
1741 if ( ((symbol->n_type & N_TYPE) == N_SECT) && ((symbol->n_desc & N_WEAK_DEF) != 0) )
1742 return true;
1743 // if an undefine and not referencing a weak symbol ==> coalesced
1744 if ( ((symbol->n_type & N_TYPE) != N_SECT) && ((symbol->n_desc & N_REF_TO_WEAK) != 0) )
1745 return true;
1746
1747 // regular symbol
1748 return false;
1749 }
1750
1751
1752 static void __attribute__((noreturn)) throwSymbolNotFound(const char* symbol, const char* referencedFrom, const char* expectedIn)
1753 {
1754 const char* formatString = "Symbol not found: %s\n Referenced from: %s\n Expected in: %s\n";
1755 char buf[strlen(symbol)+strlen(referencedFrom)+strlen(expectedIn)+strlen(formatString)];
1756 sprintf(buf, formatString, symbol, referencedFrom, expectedIn);
1757 throw strdup(buf); // this is a leak if exception doesn't halt program
1758 }
1759
1760 uintptr_t ImageLoaderMachO::resolveUndefined(const LinkContext& context, const struct macho_nlist* undefinedSymbol, bool twoLevel, ImageLoader** foundIn)
1761 {
1762 const char* symbolName = &fStrings[undefinedSymbol->n_un.n_strx];
1763
1764 if ( context.bindFlat || !twoLevel ) {
1765 // flat lookup
1766 if ( ((undefinedSymbol->n_type & N_PEXT) != 0) && ((undefinedSymbol->n_type & N_TYPE) == N_SECT) ) {
1767 // is a multi-module private_extern internal reference that the linker did not optimize away
1768 uintptr_t addr = undefinedSymbol->n_value + this->fSlide;
1769 *foundIn = this;
1770 return addr;
1771 }
1772 const Symbol* sym;
1773 if ( context.flatExportFinder(symbolName, &sym, foundIn) )
1774 return (*foundIn)->getExportedSymbolAddress(sym);
1775 // if a bundle is loaded privately the above will not find its exports
1776 if ( this->isBundle() && this->hasHiddenExports() ) {
1777 // look in self for needed symbol
1778 sym = this->findExportedSymbol(symbolName, NULL, false, foundIn);
1779 if ( sym != NULL )
1780 return (*foundIn)->getExportedSymbolAddress(sym);
1781 }
1782 if ( (undefinedSymbol->n_desc & N_WEAK_REF) != 0 ) {
1783 // definition can't be found anywhere
1784 // if reference is weak_import, then it is ok, just return 0
1785 return 0;
1786 }
1787 throwSymbolNotFound(symbolName, this->getPath(), "flat namespace");
1788 }
1789 else {
1790 // symbol requires searching images with coalesced symbols
1791 if ( !context.prebinding && this->needsCoalescing() && symbolRequiresCoalescing(undefinedSymbol) ) {
1792 const Symbol* sym;
1793 if ( context.coalescedExportFinder(symbolName, &sym, foundIn) )
1794 return (*foundIn)->getExportedSymbolAddress(sym);
1795 //throwSymbolNotFound(symbolName, this->getPath(), "coalesced namespace");
1796 //fprintf(stderr, "dyld: coalesced symbol %s not found in any coalesced image, falling back to two-level lookup", symbolName);
1797 }
1798
1799 // two level lookup
1800 void* hint = NULL;
1801 ImageLoader* target = NULL;
1802 uint8_t ord = GET_LIBRARY_ORDINAL(undefinedSymbol->n_desc);
1803 if ( ord == EXECUTABLE_ORDINAL ) {
1804 target = context.mainExecutable;
1805 }
1806 else if ( ord == SELF_LIBRARY_ORDINAL ) {
1807 target = this;
1808 }
1809 else if ( ord == DYNAMIC_LOOKUP_ORDINAL ) {
1810 // rnielsen: HACKHACK
1811 // flat lookup
1812 const Symbol* sym;
1813 if ( context.flatExportFinder(symbolName, &sym, foundIn) )
1814 return (*foundIn)->getExportedSymbolAddress(sym);
1815 // no image has exports this symbol
1816 // either report error or hope ZeroLink can just-in-time load an image
1817 context.undefinedHandler(symbolName);
1818 // try looking again
1819 if ( context.flatExportFinder(symbolName, &sym, foundIn) )
1820 return (*foundIn)->getExportedSymbolAddress(sym);
1821
1822 throwSymbolNotFound(symbolName, this->getPath(), "dynamic lookup");
1823 }
1824 else if ( ord <= fLibrariesCount ) {
1825 DependentLibrary& libInfo = fLibraries[ord-1];
1826 target = libInfo.image;
1827 if ( (target == NULL) && (((undefinedSymbol->n_desc & N_WEAK_REF) != 0) || !libInfo.required) ) {
1828 // if target library not loaded and reference is weak or library is weak return 0
1829 return 0;
1830 }
1831 }
1832 else {
1833 throw "corrupt binary, library ordinal too big";
1834 }
1835
1836 if ( target == NULL ) {
1837 //fprintf(stderr, "resolveUndefined(%s) in %s\n", symbolName, this->getPath());
1838 throw "symbol not found";
1839 }
1840
1841 // interpret hint
1842 if ( fTwoLevelHints != NULL ) {
1843 uint32_t symIndex = undefinedSymbol - fSymbolTable;
1844 int32_t undefinedIndex = symIndex - fDynamicInfo->iundefsym;
1845 if ( (undefinedIndex >= 0) && ((uint32_t)undefinedIndex < fDynamicInfo->nundefsym) ) {
1846 const struct twolevel_hint* hints = (struct twolevel_hint*)(&fLinkEditBase[fTwoLevelHints->offset]);
1847 const struct twolevel_hint* theHint = &hints[undefinedIndex];
1848 hint = (void*)theHint;
1849 }
1850 }
1851
1852 const Symbol* sym = target->findExportedSymbol(symbolName, hint, true, foundIn);
1853 if ( sym!= NULL ) {
1854 return (*foundIn)->getExportedSymbolAddress(sym);
1855 }
1856 else if ( (undefinedSymbol->n_type & N_PEXT) != 0 ) {
1857 // don't know why the static linker did not eliminate the internal reference to a private extern definition
1858 *foundIn = this;
1859 return undefinedSymbol->n_value + fSlide;
1860 }
1861 else if ( (undefinedSymbol->n_desc & N_WEAK_REF) != 0 ) {
1862 // if definition not found and reference is weak return 0
1863 return 0;
1864 }
1865
1866 // nowhere to be found
1867 throwSymbolNotFound(symbolName, this->getPath(), target->getPath());
1868 }
1869 }
1870
1871 // returns if 'addr' is within the address range of section 'sectionIndex'
1872 // fSlide is not used. 'addr' is assumed to be a prebound address in this image
1873 bool ImageLoaderMachO::isAddrInSection(uintptr_t addr, uint8_t sectionIndex)
1874 {
1875 uint8_t currentSectionIndex = 1;
1876 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
1877 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
1878 const struct load_command* cmd = cmds;
1879 for (unsigned long i = 0; i < cmd_count; ++i) {
1880 if ( cmd->cmd == LC_SEGMENT_COMMAND ) {
1881 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
1882 if ( (currentSectionIndex <= sectionIndex) && (sectionIndex < currentSectionIndex+seg->nsects) ) {
1883 // 'sectionIndex' is in this segment, get section info
1884 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
1885 const struct macho_section* const section = &sectionsStart[sectionIndex-currentSectionIndex];
1886 return ( (section->addr <= addr) && (addr < section->addr+section->size) );
1887 }
1888 else {
1889 // 'sectionIndex' not in this segment, skip to next segment
1890 currentSectionIndex += seg->nsects;
1891 }
1892 }
1893 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
1894 }
1895
1896 return false;
1897 }
1898
1899 void ImageLoaderMachO::doBindExternalRelocations(const LinkContext& context, bool onlyCoalescedSymbols)
1900 {
1901 const uintptr_t relocBase = this->getRelocBase();
1902 const bool twoLevel = this->usesTwoLevelNameSpace();
1903 const bool prebound = this->isPrebindable();
1904
1905 // if there are __TEXT fixups, temporarily make __TEXT writable
1906 if ( fTextSegmentWithFixups != NULL )
1907 fTextSegmentWithFixups->tempWritable();
1908
1909 // cache last lookup
1910 const struct macho_nlist* lastUndefinedSymbol = 0;
1911 uintptr_t symbolAddr = 0;
1912 ImageLoader* image = NULL;
1913
1914 // loop through all external relocation records and bind each
1915 const relocation_info* const relocsStart = (struct relocation_info*)(&fLinkEditBase[fDynamicInfo->extreloff]);
1916 const relocation_info* const relocsEnd = &relocsStart[fDynamicInfo->nextrel];
1917 for (const relocation_info* reloc=relocsStart; reloc < relocsEnd; ++reloc) {
1918 if (reloc->r_length == RELOC_SIZE) {
1919 switch(reloc->r_type) {
1920 case POINTER_RELOC:
1921 {
1922 const struct macho_nlist* undefinedSymbol = &fSymbolTable[reloc->r_symbolnum];
1923 // if only processing coalesced symbols and this one does not require coalesceing, skip to next
1924 if ( onlyCoalescedSymbols && !symbolRequiresCoalescing(undefinedSymbol) )
1925 continue;
1926 uintptr_t* location = ((uintptr_t*)(reloc->r_address + relocBase));
1927 uintptr_t value = *location;
1928 #if __i386__
1929 if ( reloc->r_pcrel ) {
1930 value += (uintptr_t)location + 4 - fSlide;
1931 }
1932 #endif
1933 if ( prebound ) {
1934 // we are doing relocations, so prebinding was not usable
1935 // in a prebound executable, the n_value field of an undefined symbol is set to the address where the symbol was found when prebound
1936 // so, subtracting that gives the initial displacement which we need to add to the newly found symbol address
1937 // if mach-o relocation structs had an "addend" field this complication would not be necessary.
1938 if ( ((undefinedSymbol->n_type & N_TYPE) == N_SECT) && ((undefinedSymbol->n_desc & N_WEAK_DEF) != 0) ) {
1939 // weak symbols need special casing, since *location may have been prebound to a definition in another image.
1940 // If *location is currently prebound to somewhere in the same section as the weak definition, we assume
1941 // that we can subtract off the weak symbol address to get the addend.
1942 // If prebound elsewhere, we've lost the addend and have to assume it is zero.
1943 // The prebinding to elsewhere only happens with 10.4+ update_prebinding which only operates on a small set of Apple dylibs
1944 if ( (value == undefinedSymbol->n_value) || this->isAddrInSection(value, undefinedSymbol->n_sect) )
1945 value -= undefinedSymbol->n_value;
1946 else
1947 value = 0;
1948 }
1949 else {
1950 // is undefined or non-weak symbol, so do subtraction to get addend
1951 value -= undefinedSymbol->n_value;
1952 }
1953 }
1954 // if undefinedSymbol is same as last time, then symbolAddr and image will resolve to the same too
1955 if ( undefinedSymbol != lastUndefinedSymbol ) {
1956 symbolAddr = this->resolveUndefined(context, undefinedSymbol, twoLevel, &image);
1957 lastUndefinedSymbol = undefinedSymbol;
1958 }
1959 if ( context.verboseBind ) {
1960 const char *path = NULL;
1961 if(NULL != image) {
1962 path = image->getShortName();
1963 }
1964 if(0 == value) {
1965 fprintf(stderr, "dyld: bind: %s:0x%08lx = %s:%s, *0x%08lx = 0x%08lx\n",
1966 this->getShortName(), (uintptr_t)location,
1967 path, &fStrings[undefinedSymbol->n_un.n_strx], (uintptr_t)location, symbolAddr);
1968 }
1969 else {
1970 fprintf(stderr, "dyld: bind: %s:0x%08lx = %s:%s, *0x%08lx = 0x%08lx + %ld\n",
1971 this->getShortName(), (uintptr_t)location,
1972 path, &fStrings[undefinedSymbol->n_un.n_strx], (uintptr_t)location, symbolAddr, value);
1973 }
1974 }
1975 value += symbolAddr;
1976 #if __i386__
1977 if ( reloc->r_pcrel ) {
1978 *location = value - ((uintptr_t)location + 4);
1979 }
1980 else {
1981 // don't dirty page if prebound value was correct
1982 if ( !prebound || (*location != value) )
1983 *location = value;
1984 }
1985 #else
1986 // don't dirty page if prebound value was correct
1987 if ( !prebound || (*location != value) )
1988 *location = value;
1989 #endif
1990 }
1991 break;
1992 default:
1993 throw "unknown external relocation type";
1994 }
1995 }
1996 else {
1997 throw "bad external relocation length";
1998 }
1999 }
2000
2001 // if there were __TEXT fixups, restore write protection
2002 if ( fTextSegmentWithFixups != NULL ) {
2003 fTextSegmentWithFixups->setPermissions();
2004 sys_icache_invalidate((void*)fTextSegmentWithFixups->getActualLoadAddress(), fTextSegmentWithFixups->getSize());
2005 }
2006
2007 // update stats
2008 fgTotalBindFixups += fDynamicInfo->nextrel;
2009 }
2010
2011 const mach_header* ImageLoaderMachO::machHeader() const
2012 {
2013 return (mach_header*)fMachOData;
2014 }
2015
2016 uintptr_t ImageLoaderMachO::getSlide() const
2017 {
2018 return fSlide;
2019 }
2020
2021 // hmm. maybe this should be up in ImageLoader??
2022 const void* ImageLoaderMachO::getBaseAddress() const
2023 {
2024 Segment* seg = fSegments[0];
2025 return (const void*)seg->getActualLoadAddress();
2026 }
2027
2028 uintptr_t ImageLoaderMachO::bindIndirectSymbol(uintptr_t* ptrToBind, const struct macho_section* sect, const char* symbolName, uintptr_t targetAddr, ImageLoader* targetImage, const LinkContext& context)
2029 {
2030 if ( context.verboseBind ) {
2031 const char* path = NULL;
2032 if ( targetImage != NULL )
2033 path = targetImage->getShortName();
2034 fprintf(stderr, "dyld: bind: %s:%s$%s = %s:%s, *0x%08lx = 0x%08lx\n",
2035 this->getShortName(), symbolName, (((sect->flags & SECTION_TYPE)==S_NON_LAZY_SYMBOL_POINTERS) ? "non_lazy_ptr" : "lazy_ptr"),
2036 path, symbolName, (uintptr_t)ptrToBind, targetAddr);
2037 }
2038 if ( context.bindingHandler != NULL ) {
2039 const char* path = NULL;
2040 if ( targetImage != NULL )
2041 path = targetImage->getShortName();
2042 targetAddr = (uintptr_t)context.bindingHandler(path, symbolName, (void *)targetAddr);
2043 }
2044 #if __i386__
2045 // i386 has special self-modifying stubs that change from "CALL rel32" to "JMP rel32"
2046 if ( ((sect->flags & SECTION_TYPE) == S_SYMBOL_STUBS) && ((sect->flags & S_ATTR_SELF_MODIFYING_CODE) != 0) && (sect->reserved2 == 5) ) {
2047 uint32_t rel32 = targetAddr - (((uint32_t)ptrToBind)+5);
2048 // re-write instruction in a thread-safe manner
2049 // use 8-byte compare-and-swap to alter 5-byte jump table entries
2050 // loop is required in case the extra three bytes that cover the next entry are altered by another thread
2051 bool done = false;
2052 while ( !done ) {
2053 volatile int64_t* jumpPtr = (int64_t*)ptrToBind;
2054 int pad = 0;
2055 // By default the three extra bytes swapped follow the 5-byte JMP.
2056 // But, if the 5-byte jump is up against the end of the __IMPORT segment
2057 // We don't want to access bytes off the end of the segment, so we shift
2058 // the extra bytes to precede the 5-byte JMP.
2059 if ( (((uint32_t)ptrToBind + 8) & 0x00000FFC) == 0x00000000 ) {
2060 jumpPtr = (int64_t*)((uint32_t)ptrToBind - 3);
2061 pad = 3;
2062 }
2063 int64_t oldEntry = *jumpPtr;
2064 union {
2065 int64_t int64;
2066 uint8_t bytes[8];
2067 } newEntry;
2068 newEntry.int64 = oldEntry;
2069 newEntry.bytes[pad+0] = 0xE9; // JMP rel32
2070 newEntry.bytes[pad+1] = rel32 & 0xFF;
2071 newEntry.bytes[pad+2] = (rel32 >> 8) & 0xFF;
2072 newEntry.bytes[pad+3] = (rel32 >> 16) & 0xFF;
2073 newEntry.bytes[pad+4] = (rel32 >> 24) & 0xFF;
2074 done = OSAtomicCompareAndSwap64Barrier(oldEntry, newEntry.int64, (int64_t*)jumpPtr);
2075 }
2076 }
2077 else
2078 #endif
2079 *ptrToBind = targetAddr;
2080 return targetAddr;
2081 }
2082
2083
2084 uintptr_t ImageLoaderMachO::doBindLazySymbol(uintptr_t* lazyPointer, const LinkContext& context)
2085 {
2086 // scan for all non-lazy-pointer sections
2087 const bool twoLevel = this->usesTwoLevelNameSpace();
2088 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
2089 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
2090 const struct load_command* cmd = cmds;
2091 const uint32_t* const indirectTable = (uint32_t*)&fLinkEditBase[fDynamicInfo->indirectsymoff];
2092 for (uint32_t i = 0; i < cmd_count; ++i) {
2093 switch (cmd->cmd) {
2094 case LC_SEGMENT_COMMAND:
2095 {
2096 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
2097 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
2098 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
2099 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
2100 const uint8_t type = sect->flags & SECTION_TYPE;
2101 uint32_t symbolIndex = INDIRECT_SYMBOL_LOCAL;
2102 if ( type == S_LAZY_SYMBOL_POINTERS ) {
2103 const uint32_t pointerCount = sect->size / sizeof(uintptr_t);
2104 uintptr_t* const symbolPointers = (uintptr_t*)(sect->addr + fSlide);
2105 if ( (lazyPointer >= symbolPointers) && (lazyPointer < &symbolPointers[pointerCount]) ) {
2106 const uint32_t indirectTableOffset = sect->reserved1;
2107 const uint32_t lazyIndex = lazyPointer - symbolPointers;
2108 symbolIndex = indirectTable[indirectTableOffset + lazyIndex];
2109 }
2110 }
2111 #if __i386__
2112 else if ( (type == S_SYMBOL_STUBS) && (sect->flags & S_ATTR_SELF_MODIFYING_CODE) && (sect->reserved2 == 5) ) {
2113 // 5 bytes stubs on i386 are new "fast stubs"
2114 uint8_t* const jmpTableBase = (uint8_t*)(sect->addr + fSlide);
2115 uint8_t* const jmpTableEnd = jmpTableBase + sect->size;
2116 // initial CALL instruction in jump table leaves pointer to next entry, so back up
2117 uint8_t* const jmpTableEntryToPatch = ((uint8_t*)lazyPointer) - 5;
2118 lazyPointer = (uintptr_t*)jmpTableEntryToPatch;
2119 if ( (jmpTableEntryToPatch >= jmpTableBase) && (jmpTableEntryToPatch < jmpTableEnd) ) {
2120 const uint32_t indirectTableOffset = sect->reserved1;
2121 const uint32_t entryIndex = (jmpTableEntryToPatch - jmpTableBase)/5;
2122 symbolIndex = indirectTable[indirectTableOffset + entryIndex];
2123 }
2124 }
2125 #endif
2126 if ( symbolIndex != INDIRECT_SYMBOL_ABS && symbolIndex != INDIRECT_SYMBOL_LOCAL ) {
2127 const char* symbolName = &fStrings[fSymbolTable[symbolIndex].n_un.n_strx];
2128 ImageLoader* image = NULL;
2129 uintptr_t symbolAddr = this->resolveUndefined(context, &fSymbolTable[symbolIndex], twoLevel, &image);
2130 symbolAddr = this->bindIndirectSymbol(lazyPointer, sect, symbolName, symbolAddr, image, context);
2131 ++fgTotalLazyBindFixups;
2132 return symbolAddr;
2133 }
2134 }
2135 }
2136 break;
2137 }
2138 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2139 }
2140 throw "lazy pointer not found";
2141 }
2142
2143
2144
2145
2146 void ImageLoaderMachO::doBindIndirectSymbolPointers(const LinkContext& context, BindingLaziness bindness, bool onlyCoalescedSymbols)
2147 {
2148 // scan for all non-lazy-pointer sections
2149 const bool twoLevel = this->usesTwoLevelNameSpace();
2150 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
2151 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
2152 const struct load_command* cmd = cmds;
2153 const uint32_t* const indirectTable = (uint32_t*)&fLinkEditBase[fDynamicInfo->indirectsymoff];
2154 for (uint32_t i = 0; i < cmd_count; ++i) {
2155 switch (cmd->cmd) {
2156 case LC_SEGMENT_COMMAND:
2157 {
2158 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
2159 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
2160 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
2161 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
2162 const uint8_t type = sect->flags & SECTION_TYPE;
2163 uint32_t elementSize = sizeof(uintptr_t);
2164 uint32_t elementCount = sect->size / elementSize;
2165 if ( type == S_NON_LAZY_SYMBOL_POINTERS ) {
2166 if ( (bindness == kLazyOnly) || (bindness == kLazyOnlyNoDependents) )
2167 continue;
2168 }
2169 else if ( type == S_LAZY_SYMBOL_POINTERS ) {
2170 // process each symbol pointer in this section
2171 fgTotalPossibleLazyBindFixups += elementCount;
2172 if ( bindness == kNonLazyOnly )
2173 continue;
2174 }
2175 #if __i386__
2176 else if ( (type == S_SYMBOL_STUBS) && (sect->flags & S_ATTR_SELF_MODIFYING_CODE) && (sect->reserved2 == 5) ) {
2177 // process each jmp entry in this section
2178 elementCount = sect->size / 5;
2179 elementSize = 5;
2180 fgTotalPossibleLazyBindFixups += elementCount;
2181 if ( bindness == kNonLazyOnly )
2182 continue;
2183 }
2184 #endif
2185 else {
2186 continue;
2187 }
2188 const uint32_t indirectTableOffset = sect->reserved1;
2189 uint8_t* ptrToBind = (uint8_t*)(sect->addr + fSlide);
2190 for (uint32_t j=0; j < elementCount; ++j, ptrToBind += elementSize) {
2191 uint32_t symbolIndex = indirectTable[indirectTableOffset + j];
2192 if ( symbolIndex == INDIRECT_SYMBOL_LOCAL) {
2193 *((uintptr_t*)ptrToBind) += this->fSlide;
2194 }
2195 else if ( symbolIndex == INDIRECT_SYMBOL_ABS) {
2196 // do nothing since already has absolute address
2197 }
2198 else {
2199 const struct macho_nlist* sym = &fSymbolTable[symbolIndex];
2200 if ( symbolIndex == 0 ) {
2201 // This could be rdar://problem/3534709
2202 if ( ((const macho_header*)fMachOData)->filetype == MH_EXECUTE ) {
2203 static bool alreadyWarned = false;
2204 if ( (sym->n_type & N_TYPE) != N_UNDF ) {
2205 // The indirect table parallels the (non)lazy pointer sections. For
2206 // instance, to find info about the fifth lazy pointer you look at the
2207 // fifth entry in the indirect table. (try otool -Iv on a file).
2208 // The entry in the indirect table contains an index into the symbol table.
2209
2210 // The bug in ld caused the entry in the indirect table to be zero
2211 // (instead of a magic value that means a local symbol). So, if the
2212 // symbolIndex == 0, we may be encountering the bug, or 0 may be a valid
2213 // symbol table index. The check I put in place is to see if the zero'th
2214 // symbol table entry is an import entry (usually it is a local symbol
2215 // definition).
2216 if ( context.verboseWarnings && !alreadyWarned ) {
2217 fprintf(stderr, "dyld: malformed executable '%s', skipping indirect symbol to %s\n",
2218 this->getPath(), &fStrings[sym->n_un.n_strx]);
2219 alreadyWarned = true;
2220 }
2221 continue;
2222 }
2223 }
2224 }
2225 ImageLoader *image = NULL;
2226 // if only processing coalesced symbols and this one does not require coalesceing, skip to next
2227 if ( onlyCoalescedSymbols && !symbolRequiresCoalescing(sym) )
2228 continue;
2229 uintptr_t symbolAddr;
2230 symbolAddr = resolveUndefined(context, sym, twoLevel, &image);
2231
2232 // update pointer
2233 symbolAddr = this->bindIndirectSymbol((uintptr_t*)ptrToBind, sect, &fStrings[sym->n_un.n_strx], symbolAddr, image, context);
2234 }
2235 }
2236 // update stats
2237 fgTotalBindFixups += elementCount;
2238 }
2239 }
2240 break;
2241 }
2242 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2243 }
2244 }
2245
2246 /*
2247 * The address of these symbols are written in to the (__DATA,__dyld) section
2248 * at the following offsets:
2249 * at offset 0 stub_binding_helper_interface
2250 * at offset 4 _dyld_func_lookup
2251 * at offset 8 start_debug_thread
2252 * The 'C' types (if any) for these symbols are ignored here and all are
2253 * declared as longs so the assignment of their address in to the section will
2254 * not require a cast. stub_binding_helper_interface is really a label in the
2255 * assembly code interface for the stub binding. It does not have a meaningful
2256 * 'C' type. _dyld_func_lookup is the routine in dyld_libfuncs.c.
2257 * start_debug_thread is the routine in debug.c.
2258 *
2259 * For ppc the image's stub_binding_binding_helper is read from:
2260 * at offset 20 the image's stub_binding_binding_helper address
2261 * and saved into to the image structure.
2262 */
2263 struct DATAdyld {
2264 void* dyldLazyBinder; // filled in at launch by dyld to point into dyld to &stub_binding_helper_interface
2265 void* dyldFuncLookup; // filled in at launch by dyld to point into dyld to &_dyld_func_lookup
2266 void* startDebugThread; // debugger interface ???
2267 void* debugPort; // debugger interface ???
2268 void* debugThread; // debugger interface ???
2269 void* stubBindHelper; // filled in at static link time to point to stub helper in image
2270 void* coreDebug; // ???
2271 };
2272
2273 // These are defined in dyldStartup.s
2274 extern "C" void stub_binding_helper();
2275 extern "C" bool dyld_func_lookup(const char* name, uintptr_t* address);
2276 extern "C" void fast_stub_binding_helper_interface();
2277
2278
2279 void ImageLoaderMachO::setupLazyPointerHandler(const LinkContext& context)
2280 {
2281 if ( fDATAdyld != NULL ) {
2282 struct DATAdyld* dd = (struct DATAdyld*)(fDATAdyld->addr + fSlide);
2283 if ( fDATAdyld->size > offsetof(DATAdyld, dyldLazyBinder) ) {
2284 if ( dd->dyldLazyBinder != (void*)&stub_binding_helper )
2285 dd->dyldLazyBinder = (void*)&stub_binding_helper;
2286 }
2287 if ( fDATAdyld->size > offsetof(DATAdyld, dyldFuncLookup) ) {
2288 if ( dd->dyldFuncLookup != (void*)&dyld_func_lookup )
2289 dd->dyldFuncLookup = (void*)&dyld_func_lookup;
2290 }
2291 //if ( fDATAdyld->size > offsetof(DATAdyld, startDebugThread) )
2292 // dd->startDebugThread = &start_debug_thread;
2293 #ifdef __ppc__
2294 //if ( fDATAdyld->size > offsetof(DATAdyld, stubBindHelper) )
2295 // save = dd->stubBindHelper;
2296 #endif
2297 }
2298 #if __i386__
2299 if ( ! this->usablePrebinding(context) || !this->usesTwoLevelNameSpace() ) {
2300 // reset all "fast" stubs
2301 const uint32_t cmd_count = ((macho_header*)fMachOData)->ncmds;
2302 const struct load_command* const cmds = (struct load_command*)&fMachOData[sizeof(macho_header)];
2303 const struct load_command* cmd = cmds;
2304 for (uint32_t i = 0; i < cmd_count; ++i) {
2305 switch (cmd->cmd) {
2306 case LC_SEGMENT_COMMAND:
2307 {
2308 const struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
2309 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
2310 const struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
2311 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
2312 const uint8_t type = sect->flags & SECTION_TYPE;
2313 if ( (type == S_SYMBOL_STUBS) && (sect->flags & S_ATTR_SELF_MODIFYING_CODE) && (sect->reserved2 == 5) ) {
2314 // reset each jmp entry in this section
2315 const uint32_t indirectTableOffset = sect->reserved1;
2316 const uint32_t* const indirectTable = (uint32_t*)&fLinkEditBase[fDynamicInfo->indirectsymoff];
2317 uint8_t* start = (uint8_t*)(sect->addr + this->fSlide);
2318 uint8_t* end = start + sect->size;
2319 uintptr_t dyldHandler = (uintptr_t)&fast_stub_binding_helper_interface;
2320 uint32_t entryIndex = 0;
2321 for (uint8_t* entry = start; entry < end; entry += 5, ++entryIndex) {
2322 bool installLazyHandler = true;
2323 // jump table entries that cross a (64-byte) cache line boundary have the potential to cause crashes
2324 // if the instruction is updated by one thread while being executed by another
2325 if ( ((uint32_t)entry & 0xFFFFFFC0) != ((uint32_t)entry+4 & 0xFFFFFFC0) ) {
2326 // need to bind this now to avoid a potential problem if bound lazily
2327 uint32_t symbolIndex = indirectTable[indirectTableOffset + entryIndex];
2328 // the latest linker marks 64-byte crossing stubs with INDIRECT_SYMBOL_ABS so they are not used
2329 if ( symbolIndex != INDIRECT_SYMBOL_ABS ) {
2330 const char* symbolName = &fStrings[fSymbolTable[symbolIndex].n_un.n_strx];
2331 ImageLoader* image = NULL;
2332 try {
2333 uintptr_t symbolAddr = this->resolveUndefined(context, &fSymbolTable[symbolIndex], this->usesTwoLevelNameSpace(), &image);
2334 symbolAddr = this->bindIndirectSymbol((uintptr_t*)entry, sect, symbolName, symbolAddr, image, context);
2335 ++fgTotalBindFixups;
2336 uint32_t rel32 = symbolAddr - (((uint32_t)entry)+5);
2337 entry[0] = 0xE9; // JMP rel32
2338 entry[1] = rel32 & 0xFF;
2339 entry[2] = (rel32 >> 8) & 0xFF;
2340 entry[3] = (rel32 >> 16) & 0xFF;
2341 entry[4] = (rel32 >> 24) & 0xFF;
2342 installLazyHandler = false;
2343 }
2344 catch (const char* msg) {
2345 // ignore errors when binding symbols early
2346 // maybe the function is never called, and therefore erroring out now would be a regression
2347 }
2348 }
2349 }
2350 if ( installLazyHandler ) {
2351 uint32_t rel32 = dyldHandler - (((uint32_t)entry)+5);
2352 entry[0] = 0xE8; // CALL rel32
2353 entry[1] = rel32 & 0xFF;
2354 entry[2] = (rel32 >> 8) & 0xFF;
2355 entry[3] = (rel32 >> 16) & 0xFF;
2356 entry[4] = (rel32 >> 24) & 0xFF;
2357 }
2358 }
2359 }
2360 }
2361 }
2362 }
2363 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2364 }
2365 }
2366 #endif
2367 }
2368
2369 bool ImageLoaderMachO::usablePrebinding(const LinkContext& context) const
2370 {
2371 // if prebound and loaded at prebound address, and all libraries are same as when this was prebound, then no need to bind
2372 if ( this->isPrebindable()
2373 && (this->getSlide() == 0)
2374 && (this->usesTwoLevelNameSpace() || context.prebinding)
2375 && this->allDependentLibrariesAsWhenPreBound() ) {
2376 // allow environment variables to disable prebinding
2377 if ( context.bindFlat )
2378 return false;
2379 switch ( context.prebindUsage ) {
2380 case kUseAllPrebinding:
2381 return true;
2382 case kUseSplitSegPrebinding:
2383 return this->fIsSplitSeg;
2384 case kUseAllButAppPredbinding:
2385 return (this != context.mainExecutable);
2386 case kUseNoPrebinding:
2387 return false;
2388 }
2389 }
2390 return false;
2391 }
2392
2393 void ImageLoaderMachO::doBind(const LinkContext& context, BindingLaziness bindness)
2394 {
2395 // set dyld entry points in image
2396 this->setupLazyPointerHandler(context);
2397
2398 // if prebound and loaded at prebound address, and all libraries are same as when this was prebound, then no need to bind
2399 // note: flat-namespace binaries need to be imports rebound (even if correctly prebound)
2400 if ( this->usablePrebinding(context) && this->usesTwoLevelNameSpace() ) {
2401 // if image has coalesced symbols, then these need to be rebound, unless this is the only image with weak symbols
2402 if ( this->needsCoalescing() && (fgCountOfImagesWithWeakExports > 1) ) {
2403 this->doBindExternalRelocations(context, true);
2404 this->doBindIndirectSymbolPointers(context, kLazyAndNonLazy, true);
2405 }
2406 // skip binding because prebound and prebinding not disabled
2407 return;
2408 }
2409
2410 // values bound by name are stored two different ways in mach-o
2411 switch (bindness) {
2412 case kNonLazyOnly:
2413 case kLazyAndNonLazy:
2414 // external relocations are used for data initialized to external symbols
2415 this->doBindExternalRelocations(context, false);
2416 break;
2417 case kLazyOnly:
2418 case kLazyOnlyNoDependents:
2419 break;
2420 }
2421 // "indirect symbols" are used for code references to external symbols
2422 this->doBindIndirectSymbolPointers(context, bindness, false);
2423 }
2424
2425
2426
2427 void ImageLoaderMachO::doImageInit(const LinkContext& context)
2428 {
2429 if ( fDashInit != NULL ) {
2430 Initializer func = (Initializer)(fDashInit->init_address + fSlide);
2431 if ( context.verboseInit )
2432 fprintf(stderr, "dyld: calling -init function 0x%p in %s\n", func, this->getPath());
2433 func(context.argc, context.argv, context.envp, context.apple);
2434 }
2435 }
2436
2437 void ImageLoaderMachO::doModInitFunctions(const LinkContext& context)
2438 {
2439 if ( fModInitSection != NULL ) {
2440 Initializer* inits = (Initializer*)(fModInitSection->addr + fSlide);
2441 const uint32_t count = fModInitSection->size / sizeof(uintptr_t);
2442 for (uint32_t i=0; i < count; ++i) {
2443 Initializer func = inits[i];
2444 if ( context.verboseInit )
2445 fprintf(stderr, "dyld: calling initializer function %p in %s\n", func, this->getPath());
2446 func(context.argc, context.argv, context.envp, context.apple);
2447 }
2448 }
2449 }
2450
2451
2452 void ImageLoaderMachO::doInitialization(const LinkContext& context)
2453 {
2454 // mach-o has -init and static initializers
2455 doImageInit(context);
2456 doModInitFunctions(context);
2457 }
2458
2459 bool ImageLoaderMachO::needsInitialization()
2460 {
2461 return ( (fDashInit != NULL) || (fModInitSection != NULL) );
2462 }
2463
2464
2465 bool ImageLoaderMachO::needsTermination()
2466 {
2467 return ( fModTermSection != NULL );
2468 }
2469
2470 bool ImageLoaderMachO::hasImageNotification()
2471 {
2472 return ( fImageNotifySection != NULL );
2473 }
2474
2475
2476 void ImageLoaderMachO::doTermination(const LinkContext& context)
2477 {
2478 if ( fModTermSection != NULL ) {
2479 Terminator* terms = (Terminator*)(fModTermSection->addr + fSlide);
2480 const uint32_t count = fModTermSection->size / sizeof(uintptr_t);
2481 for (uint32_t i=count; i > 0; --i) {
2482 Terminator func = terms[i-1];
2483 if ( context.verboseInit )
2484 fprintf(stderr, "dyld: calling terminaton function %p in %s\n", func, this->getPath());
2485 func();
2486 }
2487 }
2488 }
2489
2490 void ImageLoaderMachO::doNotification(enum dyld_image_mode mode, uint32_t infoCount, const struct dyld_image_info info[])
2491 {
2492 if ( fImageNotifySection != NULL ) {
2493 dyld_image_notifier* notes = (dyld_image_notifier*)(fImageNotifySection->addr + fSlide);
2494 const uint32_t count = fImageNotifySection->size / sizeof(uintptr_t);
2495 for (uint32_t i=count; i > 0; --i) {
2496 dyld_image_notifier func = notes[i-1];
2497 func(mode, infoCount, info);
2498 }
2499 }
2500 }
2501
2502 void ImageLoaderMachO::printStatistics(unsigned int imageCount)
2503 {
2504 ImageLoader::printStatistics(imageCount);
2505 fprintf(stderr, "total hinted binary tree searches: %d\n", fgHintedBinaryTreeSearchs);
2506 fprintf(stderr, "total unhinted binary tree searches: %d\n", fgUnhintedBinaryTreeSearchs);
2507 fprintf(stderr, "total images with weak exports: %d\n", fgCountOfImagesWithWeakExports);
2508
2509 #if LINKEDIT_USAGE_DEBUG
2510 fprintf(stderr, "linkedit pages accessed (%lu):\n", sLinkEditPageBuckets.size());
2511 #endif
2512 }
2513
2514 void ImageLoaderMachO::doPrebinding(const LinkContext& context, time_t timestamp, uint8_t* fileToPrebind)
2515 {
2516 // update __DATA segment
2517 this->applyPrebindingToDATA(fileToPrebind);
2518
2519 // update load commands
2520 this->applyPrebindingToLoadCommands(context, fileToPrebind, timestamp);
2521
2522 // update symbol table
2523 this->applyPrebindingToLinkEdit(context, fileToPrebind);
2524 }
2525
2526 void ImageLoaderMachO::applyPrebindingToDATA(uint8_t* fileToPrebind)
2527 {
2528 const unsigned int segmentCount = fSegments.size();
2529 for(unsigned int i=0; i < segmentCount; ++i) {
2530 SegmentMachO* seg = (SegmentMachO*)fSegments[i];
2531 if ( seg->writeable() ) {
2532 memcpy(&fileToPrebind[seg->fFileOffset], (void*)seg->getActualLoadAddress(), seg->fFileSize);
2533 }
2534 }
2535 }
2536
2537 void ImageLoaderMachO::applyPrebindingToLoadCommands(const LinkContext& context, uint8_t* fileToPrebind, time_t timestamp)
2538 {
2539 macho_header* mh = (macho_header*)fileToPrebind;
2540 const uint32_t cmd_count = mh->ncmds;
2541 const struct load_command* const cmds = (struct load_command*)&fileToPrebind[sizeof(macho_header)];
2542 const struct load_command* cmd = cmds;
2543 for (uint32_t i = 0; i < cmd_count; ++i) {
2544 switch (cmd->cmd) {
2545 case LC_LOAD_DYLIB:
2546 case LC_LOAD_WEAK_DYLIB:
2547 {
2548 // update each dylib load command with the timestamp of the target dylib
2549 struct dylib_command* dylib = (struct dylib_command*)cmd;
2550 const char* name = (char*)cmd + dylib->dylib.name.offset;
2551 for (const DependentLibrary* dl=fLibraries; dl < &fLibraries[fLibrariesCount]; dl++) {
2552 if (strcmp(dl->name, name) == 0 ) {
2553 // found matching DependentLibrary for this load command
2554 if ( dl->image == NULL ) {
2555 // missing weak linked dylib
2556 dylib->dylib.timestamp = 0;
2557 }
2558 else {
2559 ImageLoaderMachO* targetImage = (ImageLoaderMachO*)(dl->image); // !!! assume only mach-o images are prebound
2560 if ( ! targetImage->isPrebindable() )
2561 throw "dependent dylib is not prebound";
2562 // if the target is currently being re-prebound then its timestamp will be the same as this one
2563 if ( ! targetImage->usablePrebinding(context) ) {
2564 dylib->dylib.timestamp = timestamp;
2565 }
2566 else {
2567 // otherwise dependent library is already correctly prebound, so use its checksum
2568 dylib->dylib.timestamp = targetImage->doGetLibraryInfo().checksum;
2569 }
2570 }
2571 break;
2572 }
2573 }
2574 }
2575 break;
2576 case LC_ID_DYLIB:
2577 {
2578 // update the ID of this library with the new timestamp
2579 struct dylib_command* dylib = (struct dylib_command*)cmd;
2580 dylib->dylib.timestamp = timestamp;
2581 }
2582 break;
2583 case LC_SEGMENT_COMMAND:
2584 // if dylib was rebased, update segment commands
2585 if ( fSlide != 0 ) {
2586 struct macho_segment_command* seg = (struct macho_segment_command*)cmd;
2587 seg->vmaddr += fSlide;
2588 struct macho_section* const sectionsStart = (struct macho_section*)((char*)seg + sizeof(struct macho_segment_command));
2589 struct macho_section* const sectionsEnd = &sectionsStart[seg->nsects];
2590 for (struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
2591 sect->addr += fSlide;
2592 }
2593 }
2594 break;
2595 case LC_ROUTINES_COMMAND:
2596 // if dylib was rebased, update -init command
2597 if ( fSlide != 0 ) {
2598 struct macho_routines_command* routines = (struct macho_routines_command*)cmd;
2599 routines->init_address += fSlide;
2600 }
2601 break;
2602 }
2603 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2604 }
2605 }
2606
2607 void ImageLoaderMachO::applyPrebindingToLinkEdit(const LinkContext& context, uint8_t* fileToPrebind)
2608 {
2609 // In prebound images, the n_value of the symbol table entry for is the prebound address
2610 // This is needed when prebinding can't be used, to back solve for any possible addend in non-lazy pointers
2611 const char* stringPool = NULL;
2612 struct macho_nlist* symbolTable = NULL;
2613 const struct dysymtab_command* dysymtab = NULL;
2614
2615 // get symbol table info
2616 macho_header* mh = (macho_header*)fileToPrebind;
2617 const uint32_t cmd_count = mh->ncmds;
2618 const struct load_command* const cmds = (struct load_command*)&fileToPrebind[sizeof(macho_header)];
2619 const struct load_command* cmd = cmds;
2620 for (uint32_t i = 0; i < cmd_count; ++i) {
2621 switch (cmd->cmd) {
2622 case LC_SYMTAB:
2623 {
2624 const struct symtab_command* symtab = (struct symtab_command*)cmd;
2625 stringPool = (const char*)&fileToPrebind[symtab->stroff];
2626 symbolTable = (struct macho_nlist*)(&fileToPrebind[symtab->symoff]);
2627 }
2628 break;
2629 case LC_DYSYMTAB:
2630 dysymtab = (struct dysymtab_command*)cmd;
2631 break;
2632 }
2633 cmd = (const struct load_command*)(((char*)cmd)+cmd->cmdsize);
2634 }
2635
2636 // walk all imports and re-resolve their n_value (needed incase prebinding is invalid)
2637 struct macho_nlist* lastImport = &symbolTable[dysymtab->iundefsym+dysymtab->nundefsym];
2638 for (struct macho_nlist* entry = &symbolTable[dysymtab->iundefsym]; entry < lastImport; ++entry) {
2639 ImageLoader* dummy;
2640 entry->n_value = this->resolveUndefined(context, entry, this->usesTwoLevelNameSpace(), &dummy);
2641 }
2642
2643 // walk all exports and slide their n_value
2644 struct macho_nlist* lastExport = &symbolTable[dysymtab->iextdefsym+dysymtab->nextdefsym];
2645 for (struct macho_nlist* entry = &symbolTable[dysymtab->iextdefsym]; entry < lastExport; ++entry) {
2646 if ( (entry->n_type & N_TYPE) == N_SECT )
2647 entry->n_value += fSlide;
2648 }
2649
2650 // walk all local symbols and slide their n_value
2651 struct macho_nlist* lastLocal = &symbolTable[dysymtab->ilocalsym+dysymtab->nlocalsym];
2652 for (struct macho_nlist* entry = &symbolTable[dysymtab->ilocalsym]; entry < lastLocal; ++entry) {
2653 if ( entry->n_sect != NO_SECT )
2654 entry->n_value += fSlide;
2655 }
2656
2657 // walk all local relocations and reset every PPC_RELOC_PB_LA_PTR r_value
2658 relocation_info* const relocsStart = (struct relocation_info*)(&fileToPrebind[dysymtab->locreloff]);
2659 relocation_info* const relocsEnd = &relocsStart[dysymtab->nlocrel];
2660 for (relocation_info* reloc=relocsStart; reloc < relocsEnd; ++reloc) {
2661 if ( (reloc->r_address & R_SCATTERED) != 0 ) {
2662 struct scattered_relocation_info* sreloc = (struct scattered_relocation_info*)reloc;
2663 if (sreloc->r_length == RELOC_SIZE) {
2664 switch(sreloc->r_type) {
2665 #if __ppc__ || __ppc64__
2666 case PPC_RELOC_PB_LA_PTR:
2667 #elif __i386__ || __x86_64__
2668 case GENERIC_RELOC_PB_LA_PTR:
2669 #else
2670 #error unknown architecture
2671 #endif
2672 sreloc->r_value += fSlide;
2673 break;
2674 }
2675 }
2676 }
2677 }
2678
2679 // if multi-module, fix up objc_addr (10.4 and later runtime does not use this, but we want to keep file checksum consistent)
2680 if ( dysymtab->nmodtab != 0 ) {
2681 dylib_module* const modulesStart = (struct dylib_module*)(&fileToPrebind[dysymtab->modtaboff]);
2682 dylib_module* const modulesEnd = &modulesStart[dysymtab->nmodtab];
2683 for (dylib_module* module=modulesStart; module < modulesEnd; ++module) {
2684 if ( module->objc_module_info_size != 0 ) {
2685 module->objc_module_info_addr += fSlide;
2686 }
2687 }
2688 }
2689 }
2690
2691 // file on disk has been reprebound, but we are still mapped to old file
2692 void ImageLoaderMachO::prebindUnmap(const LinkContext& context)
2693 {
2694 // this removes all mappings to the old file, so the kernel will unlink (delete) it.
2695 // We need to leave the load commands and __LINKEDIT in place
2696 for (std::vector<class Segment*>::iterator it=fSegments.begin(); it != fSegments.end(); ++it) {
2697 void* segmentAddress = (void*)((*it)->getActualLoadAddress());
2698 uintptr_t segmentSize = (*it)->getSize();
2699 //fprintf(stderr, "unmapping segment %s at %p for %s\n", (*it)->getName(), segmentAddress, this->getPath());
2700 // save load commands at beginning of __TEXT segment
2701 if ( segmentAddress == fMachOData ) {
2702 // typically load commands are one or two pages in size, so ok to alloc on stack
2703 uint32_t loadCmdSize = sizeof(macho_header) + ((macho_header*)fMachOData)->sizeofcmds;
2704 uint32_t loadCmdPages = (loadCmdSize+4095) & (-4096);
2705 uint8_t loadcommands[loadCmdPages];
2706 memcpy(loadcommands, fMachOData, loadCmdPages);
2707 // unmap whole __TEXT segment
2708 munmap((void*)(fMachOData), segmentSize);
2709 // allocate and copy back mach_header and load commands
2710 vm_address_t addr = (vm_address_t)fMachOData;
2711 int r2 = vm_allocate(mach_task_self(), &addr, loadCmdPages, false /*at this address*/);
2712 if ( r2 != 0 )
2713 fprintf(stderr, "prebindUnmap() vm_allocate for __TEXT %d failed\n", loadCmdPages);
2714 memcpy((void*)fMachOData, loadcommands, loadCmdPages);
2715 //fprintf(stderr, "copying back load commands to %p size=%u for %s\n", segmentAddress, loadCmdPages, this->getPath());
2716 }
2717 else if ( strcmp((*it)->getName(), "__LINKEDIT") == 0 ) {
2718 uint32_t linkEditSize = segmentSize;
2719 uint32_t linkEditPages = (linkEditSize+4095) & (-4096);
2720 void* linkEditTmp = malloc(linkEditPages);
2721 memcpy(linkEditTmp, segmentAddress, linkEditPages);
2722 // unmap whole __LINKEDIT segment
2723 munmap(segmentAddress, segmentSize);
2724 vm_address_t addr = (vm_address_t)segmentAddress;
2725 int r2 = vm_allocate(mach_task_self(), &addr, linkEditPages, false /*at this address*/);
2726 if ( r2 != 0 )
2727 fprintf(stderr, "prebindUnmap() vm_allocate for __LINKEDIT %d failed\n", linkEditPages);
2728 memcpy(segmentAddress, linkEditTmp, linkEditPages);
2729 //fprintf(stderr, "copying back __LINKEDIT to %p size=%u for %s\n", segmentAddress, linkEditPages, this->getPath());
2730 free(linkEditTmp);
2731 }
2732 else {
2733 // unmap any other segment
2734 munmap((void*)(segmentAddress), (*it)->getSize());
2735 }
2736 }
2737 }
2738
2739
2740
2741 SegmentMachO::SegmentMachO(const struct macho_segment_command* cmd, ImageLoaderMachO* image, const uint8_t* fileData)
2742 : fImage(image), fSize(cmd->vmsize), fFileSize(cmd->filesize), fFileOffset(cmd->fileoff), fPreferredLoadAddress(cmd->vmaddr),
2743 fVMProtection(cmd->initprot), fHasFixUps(false), fUnMapOnDestruction(false)
2744 {
2745 strncpy(fName, cmd->segname, 16);
2746 fName[16] = '\0';
2747 // scan sections for fix-up bit
2748 const struct macho_section* const sectionsStart = (struct macho_section*)((char*)cmd + sizeof(struct macho_segment_command));
2749 const struct macho_section* const sectionsEnd = &sectionsStart[cmd->nsects];
2750 for (const struct macho_section* sect=sectionsStart; sect < sectionsEnd; ++sect) {
2751 if ( (sect->flags & (S_ATTR_EXT_RELOC | S_ATTR_LOC_RELOC)) != 0 )
2752 fHasFixUps = true;
2753 }
2754 }
2755
2756 SegmentMachO::~SegmentMachO()
2757 {
2758 if ( fUnMapOnDestruction ) {
2759 //fprintf(stderr, "unmapping segment %s at 0x%08lX\n", getName(), getActualLoadAddress());
2760 munmap((void*)(this->getActualLoadAddress()), this->getSize());
2761 }
2762 }
2763
2764 const ImageLoader* SegmentMachO::getImage()
2765 {
2766 return fImage;
2767 }
2768
2769 const char* SegmentMachO::getName()
2770 {
2771 return fName;
2772 }
2773
2774 uintptr_t SegmentMachO::getSize()
2775 {
2776 return fSize;
2777 }
2778
2779 uintptr_t SegmentMachO::getFileSize()
2780 {
2781 return fFileSize;
2782 }
2783
2784 uintptr_t SegmentMachO::getFileOffset()
2785 {
2786 return fFileOffset;
2787 }
2788
2789 bool SegmentMachO::readable()
2790 {
2791 return ( (fVMProtection & VM_PROT_READ) != 0);
2792 }
2793
2794 bool SegmentMachO::writeable()
2795 {
2796 return ((fVMProtection & VM_PROT_WRITE) != 0);
2797 }
2798
2799 bool SegmentMachO::executable()
2800 {
2801 return ((fVMProtection & VM_PROT_EXECUTE) != 0);
2802 }
2803
2804 bool SegmentMachO::unaccessible()
2805 {
2806 return (fVMProtection == 0);
2807 }
2808
2809 bool SegmentMachO::hasFixUps()
2810 {
2811 return fHasFixUps;
2812 }
2813
2814 uintptr_t SegmentMachO::getActualLoadAddress()
2815 {
2816 return fPreferredLoadAddress + fImage->fSlide;
2817 }
2818
2819 uintptr_t SegmentMachO::getPreferredLoadAddress()
2820 {
2821 return fPreferredLoadAddress;
2822 }
2823
2824 bool SegmentMachO::hasPreferredLoadAddress()
2825 {
2826 return (fPreferredLoadAddress != 0);
2827 }
2828
2829 void SegmentMachO::setUnMapWhenDestructed(bool unmap)
2830 {
2831 fUnMapOnDestruction = unmap;
2832 }
2833
2834 static uint32_t *buildCRCTable(void)
2835 {
2836 uint32_t *table = new uint32_t[256];
2837 uint32_t p = 0xedb88320UL; // standard CRC-32 polynomial
2838
2839 for (unsigned int i = 0; i < 256; i++) {
2840 uint32_t c = i;
2841 for (unsigned int j = 0; j < 8; j++) {
2842 if ( c & 1 ) c = p ^ (c >> 1);
2843 else c = c >> 1;
2844 }
2845 table[i] = c;
2846 }
2847
2848 return table;
2849 }
2850
2851 uint32_t SegmentMachO::crc32()
2852 {
2853 if ( !readable() ) return 0;
2854
2855 static uint32_t *crcTable = NULL;
2856 if ( !crcTable ) crcTable = buildCRCTable();
2857
2858 uint32_t crc = ~(uint32_t)0;
2859 uint8_t *p = (uint8_t *)getActualLoadAddress();
2860 uint8_t *end = p + getSize();
2861 while ( p < end ) {
2862 crc = crcTable[(crc & 0xff) ^ (*p++)] ^ (crc >> 8);
2863 }
2864 return crc ^ ~(uint32_t)0;
2865 }
2866
2867
2868
2869
2870
mirror of dyld