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