1 | /* |
2 | * Copyright (c) 1999-2019 Apple Inc. All Rights Reserved. |
3 | * |
4 | * @APPLE_LICENSE_HEADER_START@ |
5 | * |
6 | * This file contains Original Code and/or Modifications of Original Code |
7 | * as defined in and that are subject to the Apple Public Source License |
8 | * Version 2.0 (the 'License'). You may not use this file except in |
9 | * compliance with the License. Please obtain a copy of the License at |
10 | * http://www.opensource.apple.com/apsl/ and read it before using this |
11 | * file. |
12 | * |
13 | * The Original Code and all software distributed under the License are |
14 | * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER |
15 | * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, |
16 | * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, |
17 | * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. |
18 | * Please see the License for the specific language governing rights and |
19 | * limitations under the License. |
20 | * |
21 | * @APPLE_LICENSE_HEADER_END@ |
22 | */ |
23 | #ifndef _MACHO_LOADER_H_ |
24 | #define _MACHO_LOADER_H_ |
25 | |
26 | /* |
27 | * This file describes the format of mach object files. |
28 | */ |
29 | #include <stdint.h> |
30 | |
31 | /* |
32 | * <mach/machine.h> is needed here for the cpu_type_t and cpu_subtype_t types |
33 | * and contains the constants for the possible values of these types. |
34 | */ |
35 | #include <mach/machine.h> |
36 | |
37 | /* |
38 | * <mach/vm_prot.h> is needed here for the vm_prot_t type and contains the |
39 | * constants that are or'ed together for the possible values of this type. |
40 | */ |
41 | #include <mach/vm_prot.h> |
42 | |
43 | /* |
44 | * <machine/thread_status.h> is expected to define the flavors of the thread |
45 | * states and the structures of those flavors for each machine. |
46 | */ |
47 | #include <mach/machine/thread_status.h> |
48 | #include <architecture/byte_order.h> |
49 | |
50 | /* |
51 | * The 32-bit mach header appears at the very beginning of the object file for |
52 | * 32-bit architectures. |
53 | */ |
54 | struct { |
55 | uint32_t ; /* mach magic number identifier */ |
56 | cpu_type_t ; /* cpu specifier */ |
57 | cpu_subtype_t ; /* machine specifier */ |
58 | uint32_t ; /* type of file */ |
59 | uint32_t ; /* number of load commands */ |
60 | uint32_t ; /* the size of all the load commands */ |
61 | uint32_t ; /* flags */ |
62 | }; |
63 | |
64 | /* Constant for the magic field of the mach_header (32-bit architectures) */ |
65 | #define MH_MAGIC 0xfeedface /* the mach magic number */ |
66 | #define MH_CIGAM 0xcefaedfe /* NXSwapInt(MH_MAGIC) */ |
67 | |
68 | /* |
69 | * The 64-bit mach header appears at the very beginning of object files for |
70 | * 64-bit architectures. |
71 | */ |
72 | struct { |
73 | uint32_t ; /* mach magic number identifier */ |
74 | cpu_type_t ; /* cpu specifier */ |
75 | cpu_subtype_t ; /* machine specifier */ |
76 | uint32_t ; /* type of file */ |
77 | uint32_t ; /* number of load commands */ |
78 | uint32_t ; /* the size of all the load commands */ |
79 | uint32_t ; /* flags */ |
80 | uint32_t ; /* reserved */ |
81 | }; |
82 | |
83 | /* Constant for the magic field of the mach_header_64 (64-bit architectures) */ |
84 | #define MH_MAGIC_64 0xfeedfacf /* the 64-bit mach magic number */ |
85 | #define MH_CIGAM_64 0xcffaedfe /* NXSwapInt(MH_MAGIC_64) */ |
86 | |
87 | /* |
88 | * The layout of the file depends on the filetype. For all but the MH_OBJECT |
89 | * file type the segments are padded out and aligned on a segment alignment |
90 | * boundary for efficient demand pageing. The MH_EXECUTE, MH_FVMLIB, MH_DYLIB, |
91 | * MH_DYLINKER and MH_BUNDLE file types also have the headers included as part |
92 | * of their first segment. |
93 | * |
94 | * The file type MH_OBJECT is a compact format intended as output of the |
95 | * assembler and input (and possibly output) of the link editor (the .o |
96 | * format). All sections are in one unnamed segment with no segment padding. |
97 | * This format is used as an executable format when the file is so small the |
98 | * segment padding greatly increases its size. |
99 | * |
100 | * The file type MH_PRELOAD is an executable format intended for things that |
101 | * are not executed under the kernel (proms, stand alones, kernels, etc). The |
102 | * format can be executed under the kernel but may demand paged it and not |
103 | * preload it before execution. |
104 | * |
105 | * A core file is in MH_CORE format and can be any in an arbritray legal |
106 | * Mach-O file. |
107 | * |
108 | * Constants for the filetype field of the mach_header |
109 | */ |
110 | #define MH_OBJECT 0x1 /* relocatable object file */ |
111 | #define MH_EXECUTE 0x2 /* demand paged executable file */ |
112 | #define MH_FVMLIB 0x3 /* fixed VM shared library file */ |
113 | #define MH_CORE 0x4 /* core file */ |
114 | #define MH_PRELOAD 0x5 /* preloaded executable file */ |
115 | #define MH_DYLIB 0x6 /* dynamically bound shared library */ |
116 | #define MH_DYLINKER 0x7 /* dynamic link editor */ |
117 | #define MH_BUNDLE 0x8 /* dynamically bound bundle file */ |
118 | #define MH_DYLIB_STUB 0x9 /* shared library stub for static */ |
119 | /* linking only, no section contents */ |
120 | #define MH_DSYM 0xa /* companion file with only debug */ |
121 | /* sections */ |
122 | #define MH_KEXT_BUNDLE 0xb /* x86_64 kexts */ |
123 | #define MH_FILESET 0xc /* set of mach-o's */ |
124 | |
125 | /* Constants for the flags field of the mach_header */ |
126 | #define MH_NOUNDEFS 0x1 /* the object file has no undefined |
127 | references */ |
128 | #define MH_INCRLINK 0x2 /* the object file is the output of an |
129 | incremental link against a base file |
130 | and can't be link edited again */ |
131 | #define MH_DYLDLINK 0x4 /* the object file is input for the |
132 | dynamic linker and can't be staticly |
133 | link edited again */ |
134 | #define MH_BINDATLOAD 0x8 /* the object file's undefined |
135 | references are bound by the dynamic |
136 | linker when loaded. */ |
137 | #define MH_PREBOUND 0x10 /* the file has its dynamic undefined |
138 | references prebound. */ |
139 | #define MH_SPLIT_SEGS 0x20 /* the file has its read-only and |
140 | read-write segments split */ |
141 | #define MH_LAZY_INIT 0x40 /* the shared library init routine is |
142 | to be run lazily via catching memory |
143 | faults to its writeable segments |
144 | (obsolete) */ |
145 | #define MH_TWOLEVEL 0x80 /* the image is using two-level name |
146 | space bindings */ |
147 | #define MH_FORCE_FLAT 0x100 /* the executable is forcing all images |
148 | to use flat name space bindings */ |
149 | #define MH_NOMULTIDEFS 0x200 /* this umbrella guarantees no multiple |
150 | defintions of symbols in its |
151 | sub-images so the two-level namespace |
152 | hints can always be used. */ |
153 | #define MH_NOFIXPREBINDING 0x400 /* do not have dyld notify the |
154 | prebinding agent about this |
155 | executable */ |
156 | #define MH_PREBINDABLE 0x800 /* the binary is not prebound but can |
157 | have its prebinding redone. only used |
158 | when MH_PREBOUND is not set. */ |
159 | #define MH_ALLMODSBOUND 0x1000 /* indicates that this binary binds to |
160 | all two-level namespace modules of |
161 | its dependent libraries. only used |
162 | when MH_PREBINDABLE and MH_TWOLEVEL |
163 | are both set. */ |
164 | #define MH_SUBSECTIONS_VIA_SYMBOLS 0x2000/* safe to divide up the sections into |
165 | sub-sections via symbols for dead |
166 | code stripping */ |
167 | #define MH_CANONICAL 0x4000 /* the binary has been canonicalized |
168 | via the unprebind operation */ |
169 | #define MH_WEAK_DEFINES 0x8000 /* the final linked image contains |
170 | external weak symbols */ |
171 | #define MH_BINDS_TO_WEAK 0x10000 /* the final linked image uses |
172 | weak symbols */ |
173 | |
174 | #define MH_ALLOW_STACK_EXECUTION 0x20000/* When this bit is set, all stacks |
175 | in the task will be given stack |
176 | execution privilege. Only used in |
177 | MH_EXECUTE filetypes. */ |
178 | #define MH_ROOT_SAFE 0x40000 /* When this bit is set, the binary |
179 | declares it is safe for use in |
180 | processes with uid zero */ |
181 | |
182 | #define MH_SETUID_SAFE 0x80000 /* When this bit is set, the binary |
183 | declares it is safe for use in |
184 | processes when issetugid() is true */ |
185 | |
186 | #define MH_NO_REEXPORTED_DYLIBS 0x100000 /* When this bit is set on a dylib, |
187 | the static linker does not need to |
188 | examine dependent dylibs to see |
189 | if any are re-exported */ |
190 | #define MH_PIE 0x200000 /* When this bit is set, the OS will |
191 | load the main executable at a |
192 | random address. Only used in |
193 | MH_EXECUTE filetypes. */ |
194 | #define MH_DEAD_STRIPPABLE_DYLIB 0x400000 /* Only for use on dylibs. When |
195 | linking against a dylib that |
196 | has this bit set, the static linker |
197 | will automatically not create a |
198 | LC_LOAD_DYLIB load command to the |
199 | dylib if no symbols are being |
200 | referenced from the dylib. */ |
201 | #define MH_HAS_TLV_DESCRIPTORS 0x800000 /* Contains a section of type |
202 | S_THREAD_LOCAL_VARIABLES */ |
203 | |
204 | #define MH_NO_HEAP_EXECUTION 0x1000000 /* When this bit is set, the OS will |
205 | run the main executable with |
206 | a non-executable heap even on |
207 | platforms (e.g. i386) that don't |
208 | require it. Only used in MH_EXECUTE |
209 | filetypes. */ |
210 | |
211 | #define MH_APP_EXTENSION_SAFE 0x02000000 /* The code was linked for use in an |
212 | application extension. */ |
213 | |
214 | #define MH_NLIST_OUTOFSYNC_WITH_DYLDINFO 0x04000000 /* The external symbols |
215 | listed in the nlist symbol table do |
216 | not include all the symbols listed in |
217 | the dyld info. */ |
218 | |
219 | #define MH_SIM_SUPPORT 0x08000000 /* Allow LC_MIN_VERSION_MACOS and |
220 | LC_BUILD_VERSION load commands with |
221 | the platforms macOS, iOSMac, |
222 | iOSSimulator, tvOSSimulator and |
223 | watchOSSimulator. */ |
224 | |
225 | #define MH_DYLIB_IN_CACHE 0x80000000 /* Only for use on dylibs. When this bit |
226 | is set, the dylib is part of the dyld |
227 | shared cache, rather than loose in |
228 | the filesystem. */ |
229 | |
230 | /* |
231 | * The load commands directly follow the mach_header. The total size of all |
232 | * of the commands is given by the sizeofcmds field in the mach_header. All |
233 | * load commands must have as their first two fields cmd and cmdsize. The cmd |
234 | * field is filled in with a constant for that command type. Each command type |
235 | * has a structure specifically for it. The cmdsize field is the size in bytes |
236 | * of the particular load command structure plus anything that follows it that |
237 | * is a part of the load command (i.e. section structures, strings, etc.). To |
238 | * advance to the next load command the cmdsize can be added to the offset or |
239 | * pointer of the current load command. The cmdsize for 32-bit architectures |
240 | * MUST be a multiple of 4 bytes and for 64-bit architectures MUST be a multiple |
241 | * of 8 bytes (these are forever the maximum alignment of any load commands). |
242 | * The padded bytes must be zero. All tables in the object file must also |
243 | * follow these rules so the file can be memory mapped. Otherwise the pointers |
244 | * to these tables will not work well or at all on some machines. With all |
245 | * padding zeroed like objects will compare byte for byte. |
246 | */ |
247 | struct load_command { |
248 | uint32_t cmd; /* type of load command */ |
249 | uint32_t cmdsize; /* total size of command in bytes */ |
250 | }; |
251 | |
252 | /* |
253 | * After MacOS X 10.1 when a new load command is added that is required to be |
254 | * understood by the dynamic linker for the image to execute properly the |
255 | * LC_REQ_DYLD bit will be or'ed into the load command constant. If the dynamic |
256 | * linker sees such a load command it it does not understand will issue a |
257 | * "unknown load command required for execution" error and refuse to use the |
258 | * image. Other load commands without this bit that are not understood will |
259 | * simply be ignored. |
260 | */ |
261 | #define LC_REQ_DYLD 0x80000000 |
262 | |
263 | /* Constants for the cmd field of all load commands, the type */ |
264 | #define LC_SEGMENT 0x1 /* segment of this file to be mapped */ |
265 | #define LC_SYMTAB 0x2 /* link-edit stab symbol table info */ |
266 | #define LC_SYMSEG 0x3 /* link-edit gdb symbol table info (obsolete) */ |
267 | #define LC_THREAD 0x4 /* thread */ |
268 | #define LC_UNIXTHREAD 0x5 /* unix thread (includes a stack) */ |
269 | #define LC_LOADFVMLIB 0x6 /* load a specified fixed VM shared library */ |
270 | #define LC_IDFVMLIB 0x7 /* fixed VM shared library identification */ |
271 | #define LC_IDENT 0x8 /* object identification info (obsolete) */ |
272 | #define LC_FVMFILE 0x9 /* fixed VM file inclusion (internal use) */ |
273 | #define LC_PREPAGE 0xa /* prepage command (internal use) */ |
274 | #define LC_DYSYMTAB 0xb /* dynamic link-edit symbol table info */ |
275 | #define LC_LOAD_DYLIB 0xc /* load a dynamically linked shared library */ |
276 | #define LC_ID_DYLIB 0xd /* dynamically linked shared lib ident */ |
277 | #define LC_LOAD_DYLINKER 0xe /* load a dynamic linker */ |
278 | #define LC_ID_DYLINKER 0xf /* dynamic linker identification */ |
279 | #define LC_PREBOUND_DYLIB 0x10 /* modules prebound for a dynamically */ |
280 | /* linked shared library */ |
281 | #define LC_ROUTINES 0x11 /* image routines */ |
282 | #define LC_SUB_FRAMEWORK 0x12 /* sub framework */ |
283 | #define LC_SUB_UMBRELLA 0x13 /* sub umbrella */ |
284 | #define LC_SUB_CLIENT 0x14 /* sub client */ |
285 | #define LC_SUB_LIBRARY 0x15 /* sub library */ |
286 | #define LC_TWOLEVEL_HINTS 0x16 /* two-level namespace lookup hints */ |
287 | #define LC_PREBIND_CKSUM 0x17 /* prebind checksum */ |
288 | |
289 | /* |
290 | * load a dynamically linked shared library that is allowed to be missing |
291 | * (all symbols are weak imported). |
292 | */ |
293 | #define LC_LOAD_WEAK_DYLIB (0x18 | LC_REQ_DYLD) |
294 | |
295 | #define LC_SEGMENT_64 0x19 /* 64-bit segment of this file to be |
296 | mapped */ |
297 | #define LC_ROUTINES_64 0x1a /* 64-bit image routines */ |
298 | #define LC_UUID 0x1b /* the uuid */ |
299 | #define LC_RPATH (0x1c | LC_REQ_DYLD) /* runpath additions */ |
300 | #define LC_CODE_SIGNATURE 0x1d /* local of code signature */ |
301 | #define LC_SEGMENT_SPLIT_INFO 0x1e /* local of info to split segments */ |
302 | #define LC_REEXPORT_DYLIB (0x1f | LC_REQ_DYLD) /* load and re-export dylib */ |
303 | #define LC_LAZY_LOAD_DYLIB 0x20 /* delay load of dylib until first use */ |
304 | #define LC_ENCRYPTION_INFO 0x21 /* encrypted segment information */ |
305 | #define LC_DYLD_INFO 0x22 /* compressed dyld information */ |
306 | #define LC_DYLD_INFO_ONLY (0x22|LC_REQ_DYLD) /* compressed dyld information only */ |
307 | #define LC_LOAD_UPWARD_DYLIB (0x23 | LC_REQ_DYLD) /* load upward dylib */ |
308 | #define LC_VERSION_MIN_MACOSX 0x24 /* build for MacOSX min OS version */ |
309 | #define LC_VERSION_MIN_IPHONEOS 0x25 /* build for iPhoneOS min OS version */ |
310 | #define LC_FUNCTION_STARTS 0x26 /* compressed table of function start addresses */ |
311 | #define LC_DYLD_ENVIRONMENT 0x27 /* string for dyld to treat |
312 | like environment variable */ |
313 | #define LC_MAIN (0x28|LC_REQ_DYLD) /* replacement for LC_UNIXTHREAD */ |
314 | #define LC_DATA_IN_CODE 0x29 /* table of non-instructions in __text */ |
315 | #define LC_SOURCE_VERSION 0x2A /* source version used to build binary */ |
316 | #define LC_DYLIB_CODE_SIGN_DRS 0x2B /* Code signing DRs copied from linked dylibs */ |
317 | #define LC_ENCRYPTION_INFO_64 0x2C /* 64-bit encrypted segment information */ |
318 | #define LC_LINKER_OPTION 0x2D /* linker options in MH_OBJECT files */ |
319 | #define LC_LINKER_OPTIMIZATION_HINT 0x2E /* optimization hints in MH_OBJECT files */ |
320 | #define LC_VERSION_MIN_TVOS 0x2F /* build for AppleTV min OS version */ |
321 | #define LC_VERSION_MIN_WATCHOS 0x30 /* build for Watch min OS version */ |
322 | #define LC_NOTE 0x31 /* arbitrary data included within a Mach-O file */ |
323 | #define LC_BUILD_VERSION 0x32 /* build for platform min OS version */ |
324 | #define LC_DYLD_EXPORTS_TRIE (0x33 | LC_REQ_DYLD) /* used with linkedit_data_command, payload is trie */ |
325 | #define LC_DYLD_CHAINED_FIXUPS (0x34 | LC_REQ_DYLD) /* used with linkedit_data_command */ |
326 | #define LC_FILESET_ENTRY (0x35 | LC_REQ_DYLD) /* used with fileset_entry_command */ |
327 | |
328 | /* |
329 | * A variable length string in a load command is represented by an lc_str |
330 | * union. The strings are stored just after the load command structure and |
331 | * the offset is from the start of the load command structure. The size |
332 | * of the string is reflected in the cmdsize field of the load command. |
333 | * Once again any padded bytes to bring the cmdsize field to a multiple |
334 | * of 4 bytes must be zero. |
335 | */ |
336 | union lc_str { |
337 | uint32_t offset; /* offset to the string */ |
338 | #ifndef __LP64__ |
339 | char *ptr; /* pointer to the string */ |
340 | #endif |
341 | }; |
342 | |
343 | /* |
344 | * The segment load command indicates that a part of this file is to be |
345 | * mapped into the task's address space. The size of this segment in memory, |
346 | * vmsize, maybe equal to or larger than the amount to map from this file, |
347 | * filesize. The file is mapped starting at fileoff to the beginning of |
348 | * the segment in memory, vmaddr. The rest of the memory of the segment, |
349 | * if any, is allocated zero fill on demand. The segment's maximum virtual |
350 | * memory protection and initial virtual memory protection are specified |
351 | * by the maxprot and initprot fields. If the segment has sections then the |
352 | * section structures directly follow the segment command and their size is |
353 | * reflected in cmdsize. |
354 | */ |
355 | struct segment_command { /* for 32-bit architectures */ |
356 | uint32_t cmd; /* LC_SEGMENT */ |
357 | uint32_t cmdsize; /* includes sizeof section structs */ |
358 | char segname[16]; /* segment name */ |
359 | uint32_t vmaddr; /* memory address of this segment */ |
360 | uint32_t vmsize; /* memory size of this segment */ |
361 | uint32_t fileoff; /* file offset of this segment */ |
362 | uint32_t filesize; /* amount to map from the file */ |
363 | vm_prot_t maxprot; /* maximum VM protection */ |
364 | vm_prot_t initprot; /* initial VM protection */ |
365 | uint32_t nsects; /* number of sections in segment */ |
366 | uint32_t flags; /* flags */ |
367 | }; |
368 | |
369 | /* |
370 | * The 64-bit segment load command indicates that a part of this file is to be |
371 | * mapped into a 64-bit task's address space. If the 64-bit segment has |
372 | * sections then section_64 structures directly follow the 64-bit segment |
373 | * command and their size is reflected in cmdsize. |
374 | */ |
375 | struct segment_command_64 { /* for 64-bit architectures */ |
376 | uint32_t cmd; /* LC_SEGMENT_64 */ |
377 | uint32_t cmdsize; /* includes sizeof section_64 structs */ |
378 | char segname[16]; /* segment name */ |
379 | uint64_t vmaddr; /* memory address of this segment */ |
380 | uint64_t vmsize; /* memory size of this segment */ |
381 | uint64_t fileoff; /* file offset of this segment */ |
382 | uint64_t filesize; /* amount to map from the file */ |
383 | vm_prot_t maxprot; /* maximum VM protection */ |
384 | vm_prot_t initprot; /* initial VM protection */ |
385 | uint32_t nsects; /* number of sections in segment */ |
386 | uint32_t flags; /* flags */ |
387 | }; |
388 | |
389 | /* Constants for the flags field of the segment_command */ |
390 | #define SG_HIGHVM 0x1 /* the file contents for this segment is for |
391 | the high part of the VM space, the low part |
392 | is zero filled (for stacks in core files) */ |
393 | #define SG_FVMLIB 0x2 /* this segment is the VM that is allocated by |
394 | a fixed VM library, for overlap checking in |
395 | the link editor */ |
396 | #define SG_NORELOC 0x4 /* this segment has nothing that was relocated |
397 | in it and nothing relocated to it, that is |
398 | it maybe safely replaced without relocation*/ |
399 | #define SG_PROTECTED_VERSION_1 0x8 /* This segment is protected. If the |
400 | segment starts at file offset 0, the |
401 | first page of the segment is not |
402 | protected. All other pages of the |
403 | segment are protected. */ |
404 | #define SG_READ_ONLY 0x10 /* This segment is made read-only after fixups */ |
405 | |
406 | |
407 | |
408 | /* |
409 | * A segment is made up of zero or more sections. Non-MH_OBJECT files have |
410 | * all of their segments with the proper sections in each, and padded to the |
411 | * specified segment alignment when produced by the link editor. The first |
412 | * segment of a MH_EXECUTE and MH_FVMLIB format file contains the mach_header |
413 | * and load commands of the object file before its first section. The zero |
414 | * fill sections are always last in their segment (in all formats). This |
415 | * allows the zeroed segment padding to be mapped into memory where zero fill |
416 | * sections might be. The gigabyte zero fill sections, those with the section |
417 | * type S_GB_ZEROFILL, can only be in a segment with sections of this type. |
418 | * These segments are then placed after all other segments. |
419 | * |
420 | * The MH_OBJECT format has all of its sections in one segment for |
421 | * compactness. There is no padding to a specified segment boundary and the |
422 | * mach_header and load commands are not part of the segment. |
423 | * |
424 | * Sections with the same section name, sectname, going into the same segment, |
425 | * segname, are combined by the link editor. The resulting section is aligned |
426 | * to the maximum alignment of the combined sections and is the new section's |
427 | * alignment. The combined sections are aligned to their original alignment in |
428 | * the combined section. Any padded bytes to get the specified alignment are |
429 | * zeroed. |
430 | * |
431 | * The format of the relocation entries referenced by the reloff and nreloc |
432 | * fields of the section structure for mach object files is described in the |
433 | * header file <reloc.h>. |
434 | */ |
435 | struct section { /* for 32-bit architectures */ |
436 | char sectname[16]; /* name of this section */ |
437 | char segname[16]; /* segment this section goes in */ |
438 | uint32_t addr; /* memory address of this section */ |
439 | uint32_t size; /* size in bytes of this section */ |
440 | uint32_t offset; /* file offset of this section */ |
441 | uint32_t align; /* section alignment (power of 2) */ |
442 | uint32_t reloff; /* file offset of relocation entries */ |
443 | uint32_t nreloc; /* number of relocation entries */ |
444 | uint32_t flags; /* flags (section type and attributes)*/ |
445 | uint32_t reserved1; /* reserved (for offset or index) */ |
446 | uint32_t reserved2; /* reserved (for count or sizeof) */ |
447 | }; |
448 | |
449 | struct section_64 { /* for 64-bit architectures */ |
450 | char sectname[16]; /* name of this section */ |
451 | char segname[16]; /* segment this section goes in */ |
452 | uint64_t addr; /* memory address of this section */ |
453 | uint64_t size; /* size in bytes of this section */ |
454 | uint32_t offset; /* file offset of this section */ |
455 | uint32_t align; /* section alignment (power of 2) */ |
456 | uint32_t reloff; /* file offset of relocation entries */ |
457 | uint32_t nreloc; /* number of relocation entries */ |
458 | uint32_t flags; /* flags (section type and attributes)*/ |
459 | uint32_t reserved1; /* reserved (for offset or index) */ |
460 | uint32_t reserved2; /* reserved (for count or sizeof) */ |
461 | uint32_t reserved3; /* reserved */ |
462 | }; |
463 | |
464 | /* |
465 | * The flags field of a section structure is separated into two parts a section |
466 | * type and section attributes. The section types are mutually exclusive (it |
467 | * can only have one type) but the section attributes are not (it may have more |
468 | * than one attribute). |
469 | */ |
470 | #define SECTION_TYPE 0x000000ff /* 256 section types */ |
471 | #define SECTION_ATTRIBUTES 0xffffff00 /* 24 section attributes */ |
472 | |
473 | /* Constants for the type of a section */ |
474 | #define S_REGULAR 0x0 /* regular section */ |
475 | #define S_ZEROFILL 0x1 /* zero fill on demand section */ |
476 | #define S_CSTRING_LITERALS 0x2 /* section with only literal C strings*/ |
477 | #define S_4BYTE_LITERALS 0x3 /* section with only 4 byte literals */ |
478 | #define S_8BYTE_LITERALS 0x4 /* section with only 8 byte literals */ |
479 | #define S_LITERAL_POINTERS 0x5 /* section with only pointers to */ |
480 | /* literals */ |
481 | /* |
482 | * For the two types of symbol pointers sections and the symbol stubs section |
483 | * they have indirect symbol table entries. For each of the entries in the |
484 | * section the indirect symbol table entries, in corresponding order in the |
485 | * indirect symbol table, start at the index stored in the reserved1 field |
486 | * of the section structure. Since the indirect symbol table entries |
487 | * correspond to the entries in the section the number of indirect symbol table |
488 | * entries is inferred from the size of the section divided by the size of the |
489 | * entries in the section. For symbol pointers sections the size of the entries |
490 | * in the section is 4 bytes and for symbol stubs sections the byte size of the |
491 | * stubs is stored in the reserved2 field of the section structure. |
492 | */ |
493 | #define S_NON_LAZY_SYMBOL_POINTERS 0x6 /* section with only non-lazy |
494 | symbol pointers */ |
495 | #define S_LAZY_SYMBOL_POINTERS 0x7 /* section with only lazy symbol |
496 | pointers */ |
497 | #define S_SYMBOL_STUBS 0x8 /* section with only symbol |
498 | stubs, byte size of stub in |
499 | the reserved2 field */ |
500 | #define S_MOD_INIT_FUNC_POINTERS 0x9 /* section with only function |
501 | pointers for initialization*/ |
502 | #define S_MOD_TERM_FUNC_POINTERS 0xa /* section with only function |
503 | pointers for termination */ |
504 | #define S_COALESCED 0xb /* section contains symbols that |
505 | are to be coalesced */ |
506 | #define S_GB_ZEROFILL 0xc /* zero fill on demand section |
507 | (that can be larger than 4 |
508 | gigabytes) */ |
509 | #define S_INTERPOSING 0xd /* section with only pairs of |
510 | function pointers for |
511 | interposing */ |
512 | #define S_16BYTE_LITERALS 0xe /* section with only 16 byte |
513 | literals */ |
514 | #define S_DTRACE_DOF 0xf /* section contains |
515 | DTrace Object Format */ |
516 | #define S_LAZY_DYLIB_SYMBOL_POINTERS 0x10 /* section with only lazy |
517 | symbol pointers to lazy |
518 | loaded dylibs */ |
519 | /* |
520 | * Section types to support thread local variables |
521 | */ |
522 | #define S_THREAD_LOCAL_REGULAR 0x11 /* template of initial |
523 | values for TLVs */ |
524 | #define S_THREAD_LOCAL_ZEROFILL 0x12 /* template of initial |
525 | values for TLVs */ |
526 | #define S_THREAD_LOCAL_VARIABLES 0x13 /* TLV descriptors */ |
527 | #define S_THREAD_LOCAL_VARIABLE_POINTERS 0x14 /* pointers to TLV |
528 | descriptors */ |
529 | #define S_THREAD_LOCAL_INIT_FUNCTION_POINTERS 0x15 /* functions to call |
530 | to initialize TLV |
531 | values */ |
532 | #define S_INIT_FUNC_OFFSETS 0x16 /* 32-bit offsets to |
533 | initializers */ |
534 | |
535 | /* |
536 | * Constants for the section attributes part of the flags field of a section |
537 | * structure. |
538 | */ |
539 | #define SECTION_ATTRIBUTES_USR 0xff000000 /* User setable attributes */ |
540 | #define S_ATTR_PURE_INSTRUCTIONS 0x80000000 /* section contains only true |
541 | machine instructions */ |
542 | #define S_ATTR_NO_TOC 0x40000000 /* section contains coalesced |
543 | symbols that are not to be |
544 | in a ranlib table of |
545 | contents */ |
546 | #define S_ATTR_STRIP_STATIC_SYMS 0x20000000 /* ok to strip static symbols |
547 | in this section in files |
548 | with the MH_DYLDLINK flag */ |
549 | #define S_ATTR_NO_DEAD_STRIP 0x10000000 /* no dead stripping */ |
550 | #define S_ATTR_LIVE_SUPPORT 0x08000000 /* blocks are live if they |
551 | reference live blocks */ |
552 | #define S_ATTR_SELF_MODIFYING_CODE 0x04000000 /* Used with i386 code stubs |
553 | written on by dyld */ |
554 | /* |
555 | * If a segment contains any sections marked with S_ATTR_DEBUG then all |
556 | * sections in that segment must have this attribute. No section other than |
557 | * a section marked with this attribute may reference the contents of this |
558 | * section. A section with this attribute may contain no symbols and must have |
559 | * a section type S_REGULAR. The static linker will not copy section contents |
560 | * from sections with this attribute into its output file. These sections |
561 | * generally contain DWARF debugging info. |
562 | */ |
563 | #define S_ATTR_DEBUG 0x02000000 /* a debug section */ |
564 | #define SECTION_ATTRIBUTES_SYS 0x00ffff00 /* system setable attributes */ |
565 | #define S_ATTR_SOME_INSTRUCTIONS 0x00000400 /* section contains some |
566 | machine instructions */ |
567 | #define S_ATTR_EXT_RELOC 0x00000200 /* section has external |
568 | relocation entries */ |
569 | #define S_ATTR_LOC_RELOC 0x00000100 /* section has local |
570 | relocation entries */ |
571 | |
572 | |
573 | /* |
574 | * The names of segments and sections in them are mostly meaningless to the |
575 | * link-editor. But there are few things to support traditional UNIX |
576 | * executables that require the link-editor and assembler to use some names |
577 | * agreed upon by convention. |
578 | * |
579 | * The initial protection of the "__TEXT" segment has write protection turned |
580 | * off (not writeable). |
581 | * |
582 | * The link-editor will allocate common symbols at the end of the "__common" |
583 | * section in the "__DATA" segment. It will create the section and segment |
584 | * if needed. |
585 | */ |
586 | |
587 | /* The currently known segment names and the section names in those segments */ |
588 | |
589 | #define SEG_PAGEZERO "__PAGEZERO" /* the pagezero segment which has no */ |
590 | /* protections and catches NULL */ |
591 | /* references for MH_EXECUTE files */ |
592 | |
593 | |
594 | #define SEG_TEXT "__TEXT" /* the tradition UNIX text segment */ |
595 | #define SECT_TEXT "__text" /* the real text part of the text */ |
596 | /* section no headers, and no padding */ |
597 | #define SECT_FVMLIB_INIT0 "__fvmlib_init0" /* the fvmlib initialization */ |
598 | /* section */ |
599 | #define SECT_FVMLIB_INIT1 "__fvmlib_init1" /* the section following the */ |
600 | /* fvmlib initialization */ |
601 | /* section */ |
602 | |
603 | #define SEG_DATA "__DATA" /* the tradition UNIX data segment */ |
604 | #define SECT_DATA "__data" /* the real initialized data section */ |
605 | /* no padding, no bss overlap */ |
606 | #define SECT_BSS "__bss" /* the real uninitialized data section*/ |
607 | /* no padding */ |
608 | #define SECT_COMMON "__common" /* the section common symbols are */ |
609 | /* allocated in by the link editor */ |
610 | |
611 | #define SEG_OBJC "__OBJC" /* objective-C runtime segment */ |
612 | #define SECT_OBJC_SYMBOLS "__symbol_table" /* symbol table */ |
613 | #define SECT_OBJC_MODULES "__module_info" /* module information */ |
614 | #define SECT_OBJC_STRINGS "__selector_strs" /* string table */ |
615 | #define SECT_OBJC_REFS "__selector_refs" /* string table */ |
616 | |
617 | #define SEG_ICON "__ICON" /* the icon segment */ |
618 | #define "__header" /* the icon headers */ |
619 | #define SECT_ICON_TIFF "__tiff" /* the icons in tiff format */ |
620 | |
621 | #define SEG_LINKEDIT "__LINKEDIT" /* the segment containing all structs */ |
622 | /* created and maintained by the link */ |
623 | /* editor. Created with -seglinkedit */ |
624 | /* option to ld(1) for MH_EXECUTE and */ |
625 | /* FVMLIB file types only */ |
626 | |
627 | #define SEG_LINKINFO "__LINKINFO" /* the segment overlapping with linkedit */ |
628 | /* containing linking information */ |
629 | |
630 | #define SEG_UNIXSTACK "__UNIXSTACK" /* the unix stack segment */ |
631 | |
632 | #define SEG_IMPORT "__IMPORT" /* the segment for the self (dyld) */ |
633 | /* modifing code stubs that has read, */ |
634 | /* write and execute permissions */ |
635 | |
636 | /* |
637 | * Fixed virtual memory shared libraries are identified by two things. The |
638 | * target pathname (the name of the library as found for execution), and the |
639 | * minor version number. The address of where the headers are loaded is in |
640 | * header_addr. (THIS IS OBSOLETE and no longer supported). |
641 | */ |
642 | struct fvmlib { |
643 | union lc_str name; /* library's target pathname */ |
644 | uint32_t minor_version; /* library's minor version number */ |
645 | uint32_t ; /* library's header address */ |
646 | }; |
647 | |
648 | /* |
649 | * A fixed virtual shared library (filetype == MH_FVMLIB in the mach header) |
650 | * contains a fvmlib_command (cmd == LC_IDFVMLIB) to identify the library. |
651 | * An object that uses a fixed virtual shared library also contains a |
652 | * fvmlib_command (cmd == LC_LOADFVMLIB) for each library it uses. |
653 | * (THIS IS OBSOLETE and no longer supported). |
654 | */ |
655 | struct fvmlib_command { |
656 | uint32_t cmd; /* LC_IDFVMLIB or LC_LOADFVMLIB */ |
657 | uint32_t cmdsize; /* includes pathname string */ |
658 | struct fvmlib fvmlib; /* the library identification */ |
659 | }; |
660 | |
661 | /* |
662 | * Dynamicly linked shared libraries are identified by two things. The |
663 | * pathname (the name of the library as found for execution), and the |
664 | * compatibility version number. The pathname must match and the compatibility |
665 | * number in the user of the library must be greater than or equal to the |
666 | * library being used. The time stamp is used to record the time a library was |
667 | * built and copied into user so it can be use to determined if the library used |
668 | * at runtime is exactly the same as used to built the program. |
669 | */ |
670 | struct dylib { |
671 | union lc_str name; /* library's path name */ |
672 | uint32_t timestamp; /* library's build time stamp */ |
673 | uint32_t current_version; /* library's current version number */ |
674 | uint32_t compatibility_version; /* library's compatibility vers number*/ |
675 | }; |
676 | |
677 | /* |
678 | * A dynamically linked shared library (filetype == MH_DYLIB in the mach header) |
679 | * contains a dylib_command (cmd == LC_ID_DYLIB) to identify the library. |
680 | * An object that uses a dynamically linked shared library also contains a |
681 | * dylib_command (cmd == LC_LOAD_DYLIB, LC_LOAD_WEAK_DYLIB, or |
682 | * LC_REEXPORT_DYLIB) for each library it uses. |
683 | */ |
684 | struct dylib_command { |
685 | uint32_t cmd; /* LC_ID_DYLIB, LC_LOAD_{,WEAK_}DYLIB, |
686 | LC_REEXPORT_DYLIB */ |
687 | uint32_t cmdsize; /* includes pathname string */ |
688 | struct dylib dylib; /* the library identification */ |
689 | }; |
690 | |
691 | /* |
692 | * A dynamically linked shared library may be a subframework of an umbrella |
693 | * framework. If so it will be linked with "-umbrella umbrella_name" where |
694 | * Where "umbrella_name" is the name of the umbrella framework. A subframework |
695 | * can only be linked against by its umbrella framework or other subframeworks |
696 | * that are part of the same umbrella framework. Otherwise the static link |
697 | * editor produces an error and states to link against the umbrella framework. |
698 | * The name of the umbrella framework for subframeworks is recorded in the |
699 | * following structure. |
700 | */ |
701 | struct sub_framework_command { |
702 | uint32_t cmd; /* LC_SUB_FRAMEWORK */ |
703 | uint32_t cmdsize; /* includes umbrella string */ |
704 | union lc_str umbrella; /* the umbrella framework name */ |
705 | }; |
706 | |
707 | /* |
708 | * For dynamically linked shared libraries that are subframework of an umbrella |
709 | * framework they can allow clients other than the umbrella framework or other |
710 | * subframeworks in the same umbrella framework. To do this the subframework |
711 | * is built with "-allowable_client client_name" and an LC_SUB_CLIENT load |
712 | * command is created for each -allowable_client flag. The client_name is |
713 | * usually a framework name. It can also be a name used for bundles clients |
714 | * where the bundle is built with "-client_name client_name". |
715 | */ |
716 | struct sub_client_command { |
717 | uint32_t cmd; /* LC_SUB_CLIENT */ |
718 | uint32_t cmdsize; /* includes client string */ |
719 | union lc_str client; /* the client name */ |
720 | }; |
721 | |
722 | /* |
723 | * A dynamically linked shared library may be a sub_umbrella of an umbrella |
724 | * framework. If so it will be linked with "-sub_umbrella umbrella_name" where |
725 | * Where "umbrella_name" is the name of the sub_umbrella framework. When |
726 | * staticly linking when -twolevel_namespace is in effect a twolevel namespace |
727 | * umbrella framework will only cause its subframeworks and those frameworks |
728 | * listed as sub_umbrella frameworks to be implicited linked in. Any other |
729 | * dependent dynamic libraries will not be linked it when -twolevel_namespace |
730 | * is in effect. The primary library recorded by the static linker when |
731 | * resolving a symbol in these libraries will be the umbrella framework. |
732 | * Zero or more sub_umbrella frameworks may be use by an umbrella framework. |
733 | * The name of a sub_umbrella framework is recorded in the following structure. |
734 | */ |
735 | struct sub_umbrella_command { |
736 | uint32_t cmd; /* LC_SUB_UMBRELLA */ |
737 | uint32_t cmdsize; /* includes sub_umbrella string */ |
738 | union lc_str sub_umbrella; /* the sub_umbrella framework name */ |
739 | }; |
740 | |
741 | /* |
742 | * A dynamically linked shared library may be a sub_library of another shared |
743 | * library. If so it will be linked with "-sub_library library_name" where |
744 | * Where "library_name" is the name of the sub_library shared library. When |
745 | * staticly linking when -twolevel_namespace is in effect a twolevel namespace |
746 | * shared library will only cause its subframeworks and those frameworks |
747 | * listed as sub_umbrella frameworks and libraries listed as sub_libraries to |
748 | * be implicited linked in. Any other dependent dynamic libraries will not be |
749 | * linked it when -twolevel_namespace is in effect. The primary library |
750 | * recorded by the static linker when resolving a symbol in these libraries |
751 | * will be the umbrella framework (or dynamic library). Zero or more sub_library |
752 | * shared libraries may be use by an umbrella framework or (or dynamic library). |
753 | * The name of a sub_library framework is recorded in the following structure. |
754 | * For example /usr/lib/libobjc_profile.A.dylib would be recorded as "libobjc". |
755 | */ |
756 | struct sub_library_command { |
757 | uint32_t cmd; /* LC_SUB_LIBRARY */ |
758 | uint32_t cmdsize; /* includes sub_library string */ |
759 | union lc_str sub_library; /* the sub_library name */ |
760 | }; |
761 | |
762 | /* |
763 | * A program (filetype == MH_EXECUTE) that is |
764 | * prebound to its dynamic libraries has one of these for each library that |
765 | * the static linker used in prebinding. It contains a bit vector for the |
766 | * modules in the library. The bits indicate which modules are bound (1) and |
767 | * which are not (0) from the library. The bit for module 0 is the low bit |
768 | * of the first byte. So the bit for the Nth module is: |
769 | * (linked_modules[N/8] >> N%8) & 1 |
770 | */ |
771 | struct prebound_dylib_command { |
772 | uint32_t cmd; /* LC_PREBOUND_DYLIB */ |
773 | uint32_t cmdsize; /* includes strings */ |
774 | union lc_str name; /* library's path name */ |
775 | uint32_t nmodules; /* number of modules in library */ |
776 | union lc_str linked_modules; /* bit vector of linked modules */ |
777 | }; |
778 | |
779 | /* |
780 | * A program that uses a dynamic linker contains a dylinker_command to identify |
781 | * the name of the dynamic linker (LC_LOAD_DYLINKER). And a dynamic linker |
782 | * contains a dylinker_command to identify the dynamic linker (LC_ID_DYLINKER). |
783 | * A file can have at most one of these. |
784 | * This struct is also used for the LC_DYLD_ENVIRONMENT load command and |
785 | * contains string for dyld to treat like environment variable. |
786 | */ |
787 | struct dylinker_command { |
788 | uint32_t cmd; /* LC_ID_DYLINKER, LC_LOAD_DYLINKER or |
789 | LC_DYLD_ENVIRONMENT */ |
790 | uint32_t cmdsize; /* includes pathname string */ |
791 | union lc_str name; /* dynamic linker's path name */ |
792 | }; |
793 | |
794 | /* |
795 | * Thread commands contain machine-specific data structures suitable for |
796 | * use in the thread state primitives. The machine specific data structures |
797 | * follow the struct thread_command as follows. |
798 | * Each flavor of machine specific data structure is preceded by an uint32_t |
799 | * constant for the flavor of that data structure, an uint32_t that is the |
800 | * count of uint32_t's of the size of the state data structure and then |
801 | * the state data structure follows. This triple may be repeated for many |
802 | * flavors. The constants for the flavors, counts and state data structure |
803 | * definitions are expected to be in the header file <machine/thread_status.h>. |
804 | * These machine specific data structures sizes must be multiples of |
805 | * 4 bytes. The cmdsize reflects the total size of the thread_command |
806 | * and all of the sizes of the constants for the flavors, counts and state |
807 | * data structures. |
808 | * |
809 | * For executable objects that are unix processes there will be one |
810 | * thread_command (cmd == LC_UNIXTHREAD) created for it by the link-editor. |
811 | * This is the same as a LC_THREAD, except that a stack is automatically |
812 | * created (based on the shell's limit for the stack size). Command arguments |
813 | * and environment variables are copied onto that stack. |
814 | */ |
815 | struct thread_command { |
816 | uint32_t cmd; /* LC_THREAD or LC_UNIXTHREAD */ |
817 | uint32_t cmdsize; /* total size of this command */ |
818 | /* uint32_t flavor flavor of thread state */ |
819 | /* uint32_t count count of uint32_t's in thread state */ |
820 | /* struct XXX_thread_state state thread state for this flavor */ |
821 | /* ... */ |
822 | }; |
823 | |
824 | /* |
825 | * The routines command contains the address of the dynamic shared library |
826 | * initialization routine and an index into the module table for the module |
827 | * that defines the routine. Before any modules are used from the library the |
828 | * dynamic linker fully binds the module that defines the initialization routine |
829 | * and then calls it. This gets called before any module initialization |
830 | * routines (used for C++ static constructors) in the library. |
831 | */ |
832 | struct routines_command { /* for 32-bit architectures */ |
833 | uint32_t cmd; /* LC_ROUTINES */ |
834 | uint32_t cmdsize; /* total size of this command */ |
835 | uint32_t init_address; /* address of initialization routine */ |
836 | uint32_t init_module; /* index into the module table that */ |
837 | /* the init routine is defined in */ |
838 | uint32_t reserved1; |
839 | uint32_t reserved2; |
840 | uint32_t reserved3; |
841 | uint32_t reserved4; |
842 | uint32_t reserved5; |
843 | uint32_t reserved6; |
844 | }; |
845 | |
846 | /* |
847 | * The 64-bit routines command. Same use as above. |
848 | */ |
849 | struct routines_command_64 { /* for 64-bit architectures */ |
850 | uint32_t cmd; /* LC_ROUTINES_64 */ |
851 | uint32_t cmdsize; /* total size of this command */ |
852 | uint64_t init_address; /* address of initialization routine */ |
853 | uint64_t init_module; /* index into the module table that */ |
854 | /* the init routine is defined in */ |
855 | uint64_t reserved1; |
856 | uint64_t reserved2; |
857 | uint64_t reserved3; |
858 | uint64_t reserved4; |
859 | uint64_t reserved5; |
860 | uint64_t reserved6; |
861 | }; |
862 | |
863 | /* |
864 | * The symtab_command contains the offsets and sizes of the link-edit 4.3BSD |
865 | * "stab" style symbol table information as described in the header files |
866 | * <nlist.h> and <stab.h>. |
867 | */ |
868 | struct symtab_command { |
869 | uint32_t cmd; /* LC_SYMTAB */ |
870 | uint32_t cmdsize; /* sizeof(struct symtab_command) */ |
871 | uint32_t symoff; /* symbol table offset */ |
872 | uint32_t nsyms; /* number of symbol table entries */ |
873 | uint32_t stroff; /* string table offset */ |
874 | uint32_t strsize; /* string table size in bytes */ |
875 | }; |
876 | |
877 | /* |
878 | * This is the second set of the symbolic information which is used to support |
879 | * the data structures for the dynamically link editor. |
880 | * |
881 | * The original set of symbolic information in the symtab_command which contains |
882 | * the symbol and string tables must also be present when this load command is |
883 | * present. When this load command is present the symbol table is organized |
884 | * into three groups of symbols: |
885 | * local symbols (static and debugging symbols) - grouped by module |
886 | * defined external symbols - grouped by module (sorted by name if not lib) |
887 | * undefined external symbols (sorted by name if MH_BINDATLOAD is not set, |
888 | * and in order the were seen by the static |
889 | * linker if MH_BINDATLOAD is set) |
890 | * In this load command there are offsets and counts to each of the three groups |
891 | * of symbols. |
892 | * |
893 | * This load command contains a the offsets and sizes of the following new |
894 | * symbolic information tables: |
895 | * table of contents |
896 | * module table |
897 | * reference symbol table |
898 | * indirect symbol table |
899 | * The first three tables above (the table of contents, module table and |
900 | * reference symbol table) are only present if the file is a dynamically linked |
901 | * shared library. For executable and object modules, which are files |
902 | * containing only one module, the information that would be in these three |
903 | * tables is determined as follows: |
904 | * table of contents - the defined external symbols are sorted by name |
905 | * module table - the file contains only one module so everything in the |
906 | * file is part of the module. |
907 | * reference symbol table - is the defined and undefined external symbols |
908 | * |
909 | * For dynamically linked shared library files this load command also contains |
910 | * offsets and sizes to the pool of relocation entries for all sections |
911 | * separated into two groups: |
912 | * external relocation entries |
913 | * local relocation entries |
914 | * For executable and object modules the relocation entries continue to hang |
915 | * off the section structures. |
916 | */ |
917 | struct dysymtab_command { |
918 | uint32_t cmd; /* LC_DYSYMTAB */ |
919 | uint32_t cmdsize; /* sizeof(struct dysymtab_command) */ |
920 | |
921 | /* |
922 | * The symbols indicated by symoff and nsyms of the LC_SYMTAB load command |
923 | * are grouped into the following three groups: |
924 | * local symbols (further grouped by the module they are from) |
925 | * defined external symbols (further grouped by the module they are from) |
926 | * undefined symbols |
927 | * |
928 | * The local symbols are used only for debugging. The dynamic binding |
929 | * process may have to use them to indicate to the debugger the local |
930 | * symbols for a module that is being bound. |
931 | * |
932 | * The last two groups are used by the dynamic binding process to do the |
933 | * binding (indirectly through the module table and the reference symbol |
934 | * table when this is a dynamically linked shared library file). |
935 | */ |
936 | uint32_t ilocalsym; /* index to local symbols */ |
937 | uint32_t nlocalsym; /* number of local symbols */ |
938 | |
939 | uint32_t iextdefsym;/* index to externally defined symbols */ |
940 | uint32_t nextdefsym;/* number of externally defined symbols */ |
941 | |
942 | uint32_t iundefsym; /* index to undefined symbols */ |
943 | uint32_t nundefsym; /* number of undefined symbols */ |
944 | |
945 | /* |
946 | * For the for the dynamic binding process to find which module a symbol |
947 | * is defined in the table of contents is used (analogous to the ranlib |
948 | * structure in an archive) which maps defined external symbols to modules |
949 | * they are defined in. This exists only in a dynamically linked shared |
950 | * library file. For executable and object modules the defined external |
951 | * symbols are sorted by name and is use as the table of contents. |
952 | */ |
953 | uint32_t tocoff; /* file offset to table of contents */ |
954 | uint32_t ntoc; /* number of entries in table of contents */ |
955 | |
956 | /* |
957 | * To support dynamic binding of "modules" (whole object files) the symbol |
958 | * table must reflect the modules that the file was created from. This is |
959 | * done by having a module table that has indexes and counts into the merged |
960 | * tables for each module. The module structure that these two entries |
961 | * refer to is described below. This exists only in a dynamically linked |
962 | * shared library file. For executable and object modules the file only |
963 | * contains one module so everything in the file belongs to the module. |
964 | */ |
965 | uint32_t modtaboff; /* file offset to module table */ |
966 | uint32_t nmodtab; /* number of module table entries */ |
967 | |
968 | /* |
969 | * To support dynamic module binding the module structure for each module |
970 | * indicates the external references (defined and undefined) each module |
971 | * makes. For each module there is an offset and a count into the |
972 | * reference symbol table for the symbols that the module references. |
973 | * This exists only in a dynamically linked shared library file. For |
974 | * executable and object modules the defined external symbols and the |
975 | * undefined external symbols indicates the external references. |
976 | */ |
977 | uint32_t extrefsymoff; /* offset to referenced symbol table */ |
978 | uint32_t nextrefsyms; /* number of referenced symbol table entries */ |
979 | |
980 | /* |
981 | * The sections that contain "symbol pointers" and "routine stubs" have |
982 | * indexes and (implied counts based on the size of the section and fixed |
983 | * size of the entry) into the "indirect symbol" table for each pointer |
984 | * and stub. For every section of these two types the index into the |
985 | * indirect symbol table is stored in the section header in the field |
986 | * reserved1. An indirect symbol table entry is simply a 32bit index into |
987 | * the symbol table to the symbol that the pointer or stub is referring to. |
988 | * The indirect symbol table is ordered to match the entries in the section. |
989 | */ |
990 | uint32_t indirectsymoff; /* file offset to the indirect symbol table */ |
991 | uint32_t nindirectsyms; /* number of indirect symbol table entries */ |
992 | |
993 | /* |
994 | * To support relocating an individual module in a library file quickly the |
995 | * external relocation entries for each module in the library need to be |
996 | * accessed efficiently. Since the relocation entries can't be accessed |
997 | * through the section headers for a library file they are separated into |
998 | * groups of local and external entries further grouped by module. In this |
999 | * case the presents of this load command who's extreloff, nextrel, |
1000 | * locreloff and nlocrel fields are non-zero indicates that the relocation |
1001 | * entries of non-merged sections are not referenced through the section |
1002 | * structures (and the reloff and nreloc fields in the section headers are |
1003 | * set to zero). |
1004 | * |
1005 | * Since the relocation entries are not accessed through the section headers |
1006 | * this requires the r_address field to be something other than a section |
1007 | * offset to identify the item to be relocated. In this case r_address is |
1008 | * set to the offset from the vmaddr of the first LC_SEGMENT command. |
1009 | * For MH_SPLIT_SEGS images r_address is set to the the offset from the |
1010 | * vmaddr of the first read-write LC_SEGMENT command. |
1011 | * |
1012 | * The relocation entries are grouped by module and the module table |
1013 | * entries have indexes and counts into them for the group of external |
1014 | * relocation entries for that the module. |
1015 | * |
1016 | * For sections that are merged across modules there must not be any |
1017 | * remaining external relocation entries for them (for merged sections |
1018 | * remaining relocation entries must be local). |
1019 | */ |
1020 | uint32_t extreloff; /* offset to external relocation entries */ |
1021 | uint32_t nextrel; /* number of external relocation entries */ |
1022 | |
1023 | /* |
1024 | * All the local relocation entries are grouped together (they are not |
1025 | * grouped by their module since they are only used if the object is moved |
1026 | * from it staticly link edited address). |
1027 | */ |
1028 | uint32_t locreloff; /* offset to local relocation entries */ |
1029 | uint32_t nlocrel; /* number of local relocation entries */ |
1030 | |
1031 | }; |
1032 | |
1033 | /* |
1034 | * An indirect symbol table entry is simply a 32bit index into the symbol table |
1035 | * to the symbol that the pointer or stub is refering to. Unless it is for a |
1036 | * non-lazy symbol pointer section for a defined symbol which strip(1) as |
1037 | * removed. In which case it has the value INDIRECT_SYMBOL_LOCAL. If the |
1038 | * symbol was also absolute INDIRECT_SYMBOL_ABS is or'ed with that. |
1039 | */ |
1040 | #define INDIRECT_SYMBOL_LOCAL 0x80000000 |
1041 | #define INDIRECT_SYMBOL_ABS 0x40000000 |
1042 | |
1043 | |
1044 | /* a table of contents entry */ |
1045 | struct dylib_table_of_contents { |
1046 | uint32_t symbol_index; /* the defined external symbol |
1047 | (index into the symbol table) */ |
1048 | uint32_t module_index; /* index into the module table this symbol |
1049 | is defined in */ |
1050 | }; |
1051 | |
1052 | /* a module table entry */ |
1053 | struct dylib_module { |
1054 | uint32_t module_name; /* the module name (index into string table) */ |
1055 | |
1056 | uint32_t iextdefsym; /* index into externally defined symbols */ |
1057 | uint32_t nextdefsym; /* number of externally defined symbols */ |
1058 | uint32_t irefsym; /* index into reference symbol table */ |
1059 | uint32_t nrefsym; /* number of reference symbol table entries */ |
1060 | uint32_t ilocalsym; /* index into symbols for local symbols */ |
1061 | uint32_t nlocalsym; /* number of local symbols */ |
1062 | |
1063 | uint32_t iextrel; /* index into external relocation entries */ |
1064 | uint32_t nextrel; /* number of external relocation entries */ |
1065 | |
1066 | uint32_t iinit_iterm; /* low 16 bits are the index into the init |
1067 | section, high 16 bits are the index into |
1068 | the term section */ |
1069 | uint32_t ninit_nterm; /* low 16 bits are the number of init section |
1070 | entries, high 16 bits are the number of |
1071 | term section entries */ |
1072 | |
1073 | uint32_t /* for this module address of the start of */ |
1074 | objc_module_info_addr; /* the (__OBJC,__module_info) section */ |
1075 | uint32_t /* for this module size of */ |
1076 | objc_module_info_size; /* the (__OBJC,__module_info) section */ |
1077 | }; |
1078 | |
1079 | /* a 64-bit module table entry */ |
1080 | struct dylib_module_64 { |
1081 | uint32_t module_name; /* the module name (index into string table) */ |
1082 | |
1083 | uint32_t iextdefsym; /* index into externally defined symbols */ |
1084 | uint32_t nextdefsym; /* number of externally defined symbols */ |
1085 | uint32_t irefsym; /* index into reference symbol table */ |
1086 | uint32_t nrefsym; /* number of reference symbol table entries */ |
1087 | uint32_t ilocalsym; /* index into symbols for local symbols */ |
1088 | uint32_t nlocalsym; /* number of local symbols */ |
1089 | |
1090 | uint32_t iextrel; /* index into external relocation entries */ |
1091 | uint32_t nextrel; /* number of external relocation entries */ |
1092 | |
1093 | uint32_t iinit_iterm; /* low 16 bits are the index into the init |
1094 | section, high 16 bits are the index into |
1095 | the term section */ |
1096 | uint32_t ninit_nterm; /* low 16 bits are the number of init section |
1097 | entries, high 16 bits are the number of |
1098 | term section entries */ |
1099 | |
1100 | uint32_t /* for this module size of */ |
1101 | objc_module_info_size; /* the (__OBJC,__module_info) section */ |
1102 | uint64_t /* for this module address of the start of */ |
1103 | objc_module_info_addr; /* the (__OBJC,__module_info) section */ |
1104 | }; |
1105 | |
1106 | /* |
1107 | * The entries in the reference symbol table are used when loading the module |
1108 | * (both by the static and dynamic link editors) and if the module is unloaded |
1109 | * or replaced. Therefore all external symbols (defined and undefined) are |
1110 | * listed in the module's reference table. The flags describe the type of |
1111 | * reference that is being made. The constants for the flags are defined in |
1112 | * <mach-o/nlist.h> as they are also used for symbol table entries. |
1113 | */ |
1114 | struct dylib_reference { |
1115 | uint32_t isym:24, /* index into the symbol table */ |
1116 | flags:8; /* flags to indicate the type of reference */ |
1117 | }; |
1118 | |
1119 | /* |
1120 | * The twolevel_hints_command contains the offset and number of hints in the |
1121 | * two-level namespace lookup hints table. |
1122 | */ |
1123 | struct twolevel_hints_command { |
1124 | uint32_t cmd; /* LC_TWOLEVEL_HINTS */ |
1125 | uint32_t cmdsize; /* sizeof(struct twolevel_hints_command) */ |
1126 | uint32_t offset; /* offset to the hint table */ |
1127 | uint32_t nhints; /* number of hints in the hint table */ |
1128 | }; |
1129 | |
1130 | /* |
1131 | * The entries in the two-level namespace lookup hints table are twolevel_hint |
1132 | * structs. These provide hints to the dynamic link editor where to start |
1133 | * looking for an undefined symbol in a two-level namespace image. The |
1134 | * isub_image field is an index into the sub-images (sub-frameworks and |
1135 | * sub-umbrellas list) that made up the two-level image that the undefined |
1136 | * symbol was found in when it was built by the static link editor. If |
1137 | * isub-image is 0 the the symbol is expected to be defined in library and not |
1138 | * in the sub-images. If isub-image is non-zero it is an index into the array |
1139 | * of sub-images for the umbrella with the first index in the sub-images being |
1140 | * 1. The array of sub-images is the ordered list of sub-images of the umbrella |
1141 | * that would be searched for a symbol that has the umbrella recorded as its |
1142 | * primary library. The table of contents index is an index into the |
1143 | * library's table of contents. This is used as the starting point of the |
1144 | * binary search or a directed linear search. |
1145 | */ |
1146 | struct twolevel_hint { |
1147 | uint32_t |
1148 | isub_image:8, /* index into the sub images */ |
1149 | itoc:24; /* index into the table of contents */ |
1150 | }; |
1151 | |
1152 | /* |
1153 | * The prebind_cksum_command contains the value of the original check sum for |
1154 | * prebound files or zero. When a prebound file is first created or modified |
1155 | * for other than updating its prebinding information the value of the check sum |
1156 | * is set to zero. When the file has it prebinding re-done and if the value of |
1157 | * the check sum is zero the original check sum is calculated and stored in |
1158 | * cksum field of this load command in the output file. If when the prebinding |
1159 | * is re-done and the cksum field is non-zero it is left unchanged from the |
1160 | * input file. |
1161 | */ |
1162 | struct prebind_cksum_command { |
1163 | uint32_t cmd; /* LC_PREBIND_CKSUM */ |
1164 | uint32_t cmdsize; /* sizeof(struct prebind_cksum_command) */ |
1165 | uint32_t cksum; /* the check sum or zero */ |
1166 | }; |
1167 | |
1168 | /* |
1169 | * The uuid load command contains a single 128-bit unique random number that |
1170 | * identifies an object produced by the static link editor. |
1171 | */ |
1172 | struct uuid_command { |
1173 | uint32_t cmd; /* LC_UUID */ |
1174 | uint32_t cmdsize; /* sizeof(struct uuid_command) */ |
1175 | uint8_t uuid[16]; /* the 128-bit uuid */ |
1176 | }; |
1177 | |
1178 | /* |
1179 | * The rpath_command contains a path which at runtime should be added to |
1180 | * the current run path used to find @rpath prefixed dylibs. |
1181 | */ |
1182 | struct rpath_command { |
1183 | uint32_t cmd; /* LC_RPATH */ |
1184 | uint32_t cmdsize; /* includes string */ |
1185 | union lc_str path; /* path to add to run path */ |
1186 | }; |
1187 | |
1188 | /* |
1189 | * The linkedit_data_command contains the offsets and sizes of a blob |
1190 | * of data in the __LINKEDIT segment. |
1191 | */ |
1192 | struct linkedit_data_command { |
1193 | uint32_t cmd; /* LC_CODE_SIGNATURE, LC_SEGMENT_SPLIT_INFO, |
1194 | LC_FUNCTION_STARTS, LC_DATA_IN_CODE, |
1195 | LC_DYLIB_CODE_SIGN_DRS, |
1196 | LC_LINKER_OPTIMIZATION_HINT, |
1197 | LC_DYLD_EXPORTS_TRIE, or |
1198 | LC_DYLD_CHAINED_FIXUPS. */ |
1199 | uint32_t cmdsize; /* sizeof(struct linkedit_data_command) */ |
1200 | uint32_t dataoff; /* file offset of data in __LINKEDIT segment */ |
1201 | uint32_t datasize; /* file size of data in __LINKEDIT segment */ |
1202 | }; |
1203 | |
1204 | struct fileset_entry_command { |
1205 | uint32_t cmd; /* LC_FILESET_ENTRY */ |
1206 | uint32_t cmdsize; /* includes id string */ |
1207 | uint64_t vmaddr; /* memory address of the dylib */ |
1208 | uint64_t fileoff; /* file offset of the dylib */ |
1209 | union lc_str entry_id; /* contained entry id */ |
1210 | uint32_t reserved; /* entry_id is 32-bits long, so this is the reserved padding */ |
1211 | }; |
1212 | |
1213 | /* |
1214 | * The encryption_info_command contains the file offset and size of an |
1215 | * of an encrypted segment. |
1216 | */ |
1217 | struct encryption_info_command { |
1218 | uint32_t cmd; /* LC_ENCRYPTION_INFO */ |
1219 | uint32_t cmdsize; /* sizeof(struct encryption_info_command) */ |
1220 | uint32_t cryptoff; /* file offset of encrypted range */ |
1221 | uint32_t cryptsize; /* file size of encrypted range */ |
1222 | uint32_t cryptid; /* which enryption system, |
1223 | 0 means not-encrypted yet */ |
1224 | }; |
1225 | |
1226 | /* |
1227 | * The encryption_info_command_64 contains the file offset and size of an |
1228 | * of an encrypted segment (for use in x86_64 targets). |
1229 | */ |
1230 | struct encryption_info_command_64 { |
1231 | uint32_t cmd; /* LC_ENCRYPTION_INFO_64 */ |
1232 | uint32_t cmdsize; /* sizeof(struct encryption_info_command_64) */ |
1233 | uint32_t cryptoff; /* file offset of encrypted range */ |
1234 | uint32_t cryptsize; /* file size of encrypted range */ |
1235 | uint32_t cryptid; /* which enryption system, |
1236 | 0 means not-encrypted yet */ |
1237 | uint32_t pad; /* padding to make this struct's size a multiple |
1238 | of 8 bytes */ |
1239 | }; |
1240 | |
1241 | /* |
1242 | * The version_min_command contains the min OS version on which this |
1243 | * binary was built to run. |
1244 | */ |
1245 | struct version_min_command { |
1246 | uint32_t cmd; /* LC_VERSION_MIN_MACOSX or |
1247 | LC_VERSION_MIN_IPHONEOS or |
1248 | LC_VERSION_MIN_WATCHOS or |
1249 | LC_VERSION_MIN_TVOS */ |
1250 | uint32_t cmdsize; /* sizeof(struct min_version_command) */ |
1251 | uint32_t version; /* X.Y.Z is encoded in nibbles xxxx.yy.zz */ |
1252 | uint32_t sdk; /* X.Y.Z is encoded in nibbles xxxx.yy.zz */ |
1253 | }; |
1254 | |
1255 | /* |
1256 | * The build_version_command contains the min OS version on which this |
1257 | * binary was built to run for its platform. The list of known platforms and |
1258 | * tool values following it. |
1259 | */ |
1260 | struct build_version_command { |
1261 | uint32_t cmd; /* LC_BUILD_VERSION */ |
1262 | uint32_t cmdsize; /* sizeof(struct build_version_command) plus */ |
1263 | /* ntools * sizeof(struct build_tool_version) */ |
1264 | uint32_t platform; /* platform */ |
1265 | uint32_t minos; /* X.Y.Z is encoded in nibbles xxxx.yy.zz */ |
1266 | uint32_t sdk; /* X.Y.Z is encoded in nibbles xxxx.yy.zz */ |
1267 | uint32_t ntools; /* number of tool entries following this */ |
1268 | }; |
1269 | |
1270 | struct build_tool_version { |
1271 | uint32_t tool; /* enum for the tool */ |
1272 | uint32_t version; /* version number of the tool */ |
1273 | }; |
1274 | |
1275 | /* Known values for the platform field above. */ |
1276 | #define PLATFORM_MACOS 1 |
1277 | #define PLATFORM_IOS 2 |
1278 | #define PLATFORM_TVOS 3 |
1279 | #define PLATFORM_WATCHOS 4 |
1280 | #define PLATFORM_BRIDGEOS 5 |
1281 | #define PLATFORM_MACCATALYST 6 |
1282 | #define PLATFORM_IOSSIMULATOR 7 |
1283 | #define PLATFORM_TVOSSIMULATOR 8 |
1284 | #define PLATFORM_WATCHOSSIMULATOR 9 |
1285 | #define PLATFORM_DRIVERKIT 10 |
1286 | #define PLATFORM_MAX PLATFORM_DRIVERKIT |
1287 | /* Addition of simulated platfrom also needs to update proc_is_simulated() */ |
1288 | |
1289 | /* Known values for the tool field above. */ |
1290 | #define TOOL_CLANG 1 |
1291 | #define TOOL_SWIFT 2 |
1292 | #define TOOL_LD 3 |
1293 | |
1294 | /* |
1295 | * The dyld_info_command contains the file offsets and sizes of |
1296 | * the new compressed form of the information dyld needs to |
1297 | * load the image. This information is used by dyld on Mac OS X |
1298 | * 10.6 and later. All information pointed to by this command |
1299 | * is encoded using byte streams, so no endian swapping is needed |
1300 | * to interpret it. |
1301 | */ |
1302 | struct dyld_info_command { |
1303 | uint32_t cmd; /* LC_DYLD_INFO or LC_DYLD_INFO_ONLY */ |
1304 | uint32_t cmdsize; /* sizeof(struct dyld_info_command) */ |
1305 | |
1306 | /* |
1307 | * Dyld rebases an image whenever dyld loads it at an address different |
1308 | * from its preferred address. The rebase information is a stream |
1309 | * of byte sized opcodes whose symbolic names start with REBASE_OPCODE_. |
1310 | * Conceptually the rebase information is a table of tuples: |
1311 | * <seg-index, seg-offset, type> |
1312 | * The opcodes are a compressed way to encode the table by only |
1313 | * encoding when a column changes. In addition simple patterns |
1314 | * like "every n'th offset for m times" can be encoded in a few |
1315 | * bytes. |
1316 | */ |
1317 | uint32_t rebase_off; /* file offset to rebase info */ |
1318 | uint32_t rebase_size; /* size of rebase info */ |
1319 | |
1320 | /* |
1321 | * Dyld binds an image during the loading process, if the image |
1322 | * requires any pointers to be initialized to symbols in other images. |
1323 | * The bind information is a stream of byte sized |
1324 | * opcodes whose symbolic names start with BIND_OPCODE_. |
1325 | * Conceptually the bind information is a table of tuples: |
1326 | * <seg-index, seg-offset, type, symbol-library-ordinal, symbol-name, addend> |
1327 | * The opcodes are a compressed way to encode the table by only |
1328 | * encoding when a column changes. In addition simple patterns |
1329 | * like for runs of pointers initialzed to the same value can be |
1330 | * encoded in a few bytes. |
1331 | */ |
1332 | uint32_t bind_off; /* file offset to binding info */ |
1333 | uint32_t bind_size; /* size of binding info */ |
1334 | |
1335 | /* |
1336 | * Some C++ programs require dyld to unique symbols so that all |
1337 | * images in the process use the same copy of some code/data. |
1338 | * This step is done after binding. The content of the weak_bind |
1339 | * info is an opcode stream like the bind_info. But it is sorted |
1340 | * alphabetically by symbol name. This enable dyld to walk |
1341 | * all images with weak binding information in order and look |
1342 | * for collisions. If there are no collisions, dyld does |
1343 | * no updating. That means that some fixups are also encoded |
1344 | * in the bind_info. For instance, all calls to "operator new" |
1345 | * are first bound to libstdc++.dylib using the information |
1346 | * in bind_info. Then if some image overrides operator new |
1347 | * that is detected when the weak_bind information is processed |
1348 | * and the call to operator new is then rebound. |
1349 | */ |
1350 | uint32_t weak_bind_off; /* file offset to weak binding info */ |
1351 | uint32_t weak_bind_size; /* size of weak binding info */ |
1352 | |
1353 | /* |
1354 | * Some uses of external symbols do not need to be bound immediately. |
1355 | * Instead they can be lazily bound on first use. The lazy_bind |
1356 | * are contains a stream of BIND opcodes to bind all lazy symbols. |
1357 | * Normal use is that dyld ignores the lazy_bind section when |
1358 | * loading an image. Instead the static linker arranged for the |
1359 | * lazy pointer to initially point to a helper function which |
1360 | * pushes the offset into the lazy_bind area for the symbol |
1361 | * needing to be bound, then jumps to dyld which simply adds |
1362 | * the offset to lazy_bind_off to get the information on what |
1363 | * to bind. |
1364 | */ |
1365 | uint32_t lazy_bind_off; /* file offset to lazy binding info */ |
1366 | uint32_t lazy_bind_size; /* size of lazy binding infs */ |
1367 | |
1368 | /* |
1369 | * The symbols exported by a dylib are encoded in a trie. This |
1370 | * is a compact representation that factors out common prefixes. |
1371 | * It also reduces LINKEDIT pages in RAM because it encodes all |
1372 | * information (name, address, flags) in one small, contiguous range. |
1373 | * The export area is a stream of nodes. The first node sequentially |
1374 | * is the start node for the trie. |
1375 | * |
1376 | * Nodes for a symbol start with a uleb128 that is the length of |
1377 | * the exported symbol information for the string so far. |
1378 | * If there is no exported symbol, the node starts with a zero byte. |
1379 | * If there is exported info, it follows the length. |
1380 | * |
1381 | * First is a uleb128 containing flags. Normally, it is followed by |
1382 | * a uleb128 encoded offset which is location of the content named |
1383 | * by the symbol from the mach_header for the image. If the flags |
1384 | * is EXPORT_SYMBOL_FLAGS_REEXPORT, then following the flags is |
1385 | * a uleb128 encoded library ordinal, then a zero terminated |
1386 | * UTF8 string. If the string is zero length, then the symbol |
1387 | * is re-export from the specified dylib with the same name. |
1388 | * If the flags is EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER, then following |
1389 | * the flags is two uleb128s: the stub offset and the resolver offset. |
1390 | * The stub is used by non-lazy pointers. The resolver is used |
1391 | * by lazy pointers and must be called to get the actual address to use. |
1392 | * |
1393 | * After the optional exported symbol information is a byte of |
1394 | * how many edges (0-255) that this node has leaving it, |
1395 | * followed by each edge. |
1396 | * Each edge is a zero terminated UTF8 of the addition chars |
1397 | * in the symbol, followed by a uleb128 offset for the node that |
1398 | * edge points to. |
1399 | * |
1400 | */ |
1401 | uint32_t export_off; /* file offset to lazy binding info */ |
1402 | uint32_t export_size; /* size of lazy binding infs */ |
1403 | }; |
1404 | |
1405 | /* |
1406 | * The following are used to encode rebasing information |
1407 | */ |
1408 | #define REBASE_TYPE_POINTER 1 |
1409 | #define REBASE_TYPE_TEXT_ABSOLUTE32 2 |
1410 | #define REBASE_TYPE_TEXT_PCREL32 3 |
1411 | |
1412 | #define REBASE_OPCODE_MASK 0xF0 |
1413 | #define REBASE_IMMEDIATE_MASK 0x0F |
1414 | #define REBASE_OPCODE_DONE 0x00 |
1415 | #define REBASE_OPCODE_SET_TYPE_IMM 0x10 |
1416 | #define REBASE_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB 0x20 |
1417 | #define REBASE_OPCODE_ADD_ADDR_ULEB 0x30 |
1418 | #define REBASE_OPCODE_ADD_ADDR_IMM_SCALED 0x40 |
1419 | #define REBASE_OPCODE_DO_REBASE_IMM_TIMES 0x50 |
1420 | #define REBASE_OPCODE_DO_REBASE_ULEB_TIMES 0x60 |
1421 | #define REBASE_OPCODE_DO_REBASE_ADD_ADDR_ULEB 0x70 |
1422 | #define REBASE_OPCODE_DO_REBASE_ULEB_TIMES_SKIPPING_ULEB 0x80 |
1423 | |
1424 | |
1425 | /* |
1426 | * The following are used to encode binding information |
1427 | */ |
1428 | #define BIND_TYPE_POINTER 1 |
1429 | #define BIND_TYPE_TEXT_ABSOLUTE32 2 |
1430 | #define BIND_TYPE_TEXT_PCREL32 3 |
1431 | |
1432 | #define BIND_SPECIAL_DYLIB_SELF 0 |
1433 | #define BIND_SPECIAL_DYLIB_MAIN_EXECUTABLE -1 |
1434 | #define BIND_SPECIAL_DYLIB_FLAT_LOOKUP -2 |
1435 | #define BIND_SPECIAL_DYLIB_WEAK_LOOKUP -3 |
1436 | |
1437 | #define BIND_SYMBOL_FLAGS_WEAK_IMPORT 0x1 |
1438 | #define BIND_SYMBOL_FLAGS_NON_WEAK_DEFINITION 0x8 |
1439 | |
1440 | #define BIND_OPCODE_MASK 0xF0 |
1441 | #define BIND_IMMEDIATE_MASK 0x0F |
1442 | #define BIND_OPCODE_DONE 0x00 |
1443 | #define BIND_OPCODE_SET_DYLIB_ORDINAL_IMM 0x10 |
1444 | #define BIND_OPCODE_SET_DYLIB_ORDINAL_ULEB 0x20 |
1445 | #define BIND_OPCODE_SET_DYLIB_SPECIAL_IMM 0x30 |
1446 | #define BIND_OPCODE_SET_SYMBOL_TRAILING_FLAGS_IMM 0x40 |
1447 | #define BIND_OPCODE_SET_TYPE_IMM 0x50 |
1448 | #define BIND_OPCODE_SET_ADDEND_SLEB 0x60 |
1449 | #define BIND_OPCODE_SET_SEGMENT_AND_OFFSET_ULEB 0x70 |
1450 | #define BIND_OPCODE_ADD_ADDR_ULEB 0x80 |
1451 | #define BIND_OPCODE_DO_BIND 0x90 |
1452 | #define BIND_OPCODE_DO_BIND_ADD_ADDR_ULEB 0xA0 |
1453 | #define BIND_OPCODE_DO_BIND_ADD_ADDR_IMM_SCALED 0xB0 |
1454 | #define BIND_OPCODE_DO_BIND_ULEB_TIMES_SKIPPING_ULEB 0xC0 |
1455 | #define BIND_OPCODE_THREADED 0xD0 |
1456 | #define BIND_SUBOPCODE_THREADED_SET_BIND_ORDINAL_TABLE_SIZE_ULEB 0x00 |
1457 | #define BIND_SUBOPCODE_THREADED_APPLY 0x01 |
1458 | |
1459 | |
1460 | /* |
1461 | * The following are used on the flags byte of a terminal node |
1462 | * in the export information. |
1463 | */ |
1464 | #define EXPORT_SYMBOL_FLAGS_KIND_MASK 0x03 |
1465 | #define EXPORT_SYMBOL_FLAGS_KIND_REGULAR 0x00 |
1466 | #define EXPORT_SYMBOL_FLAGS_KIND_THREAD_LOCAL 0x01 |
1467 | #define EXPORT_SYMBOL_FLAGS_KIND_ABSOLUTE 0x02 |
1468 | #define EXPORT_SYMBOL_FLAGS_WEAK_DEFINITION 0x04 |
1469 | #define EXPORT_SYMBOL_FLAGS_REEXPORT 0x08 |
1470 | #define EXPORT_SYMBOL_FLAGS_STUB_AND_RESOLVER 0x10 |
1471 | |
1472 | /* |
1473 | * The linker_option_command contains linker options embedded in object files. |
1474 | */ |
1475 | struct linker_option_command { |
1476 | uint32_t cmd; /* LC_LINKER_OPTION only used in MH_OBJECT filetypes */ |
1477 | uint32_t cmdsize; |
1478 | uint32_t count; /* number of strings */ |
1479 | /* concatenation of zero terminated UTF8 strings. |
1480 | Zero filled at end to align */ |
1481 | }; |
1482 | |
1483 | /* |
1484 | * The symseg_command contains the offset and size of the GNU style |
1485 | * symbol table information as described in the header file <symseg.h>. |
1486 | * The symbol roots of the symbol segments must also be aligned properly |
1487 | * in the file. So the requirement of keeping the offsets aligned to a |
1488 | * multiple of a 4 bytes translates to the length field of the symbol |
1489 | * roots also being a multiple of a long. Also the padding must again be |
1490 | * zeroed. (THIS IS OBSOLETE and no longer supported). |
1491 | */ |
1492 | struct symseg_command { |
1493 | uint32_t cmd; /* LC_SYMSEG */ |
1494 | uint32_t cmdsize; /* sizeof(struct symseg_command) */ |
1495 | uint32_t offset; /* symbol segment offset */ |
1496 | uint32_t size; /* symbol segment size in bytes */ |
1497 | }; |
1498 | |
1499 | /* |
1500 | * The ident_command contains a free format string table following the |
1501 | * ident_command structure. The strings are null terminated and the size of |
1502 | * the command is padded out with zero bytes to a multiple of 4 bytes/ |
1503 | * (THIS IS OBSOLETE and no longer supported). |
1504 | */ |
1505 | struct ident_command { |
1506 | uint32_t cmd; /* LC_IDENT */ |
1507 | uint32_t cmdsize; /* strings that follow this command */ |
1508 | }; |
1509 | |
1510 | /* |
1511 | * The fvmfile_command contains a reference to a file to be loaded at the |
1512 | * specified virtual address. (Presently, this command is reserved for |
1513 | * internal use. The kernel ignores this command when loading a program into |
1514 | * memory). |
1515 | */ |
1516 | struct fvmfile_command { |
1517 | uint32_t cmd; /* LC_FVMFILE */ |
1518 | uint32_t cmdsize; /* includes pathname string */ |
1519 | union lc_str name; /* files pathname */ |
1520 | uint32_t header_addr; /* files virtual address */ |
1521 | }; |
1522 | |
1523 | |
1524 | /* |
1525 | * The entry_point_command is a replacement for thread_command. |
1526 | * It is used for main executables to specify the location (file offset) |
1527 | * of main(). If -stack_size was used at link time, the stacksize |
1528 | * field will contain the stack size need for the main thread. |
1529 | */ |
1530 | struct entry_point_command { |
1531 | uint32_t cmd; /* LC_MAIN only used in MH_EXECUTE filetypes */ |
1532 | uint32_t cmdsize; /* 24 */ |
1533 | uint64_t entryoff; /* file (__TEXT) offset of main() */ |
1534 | uint64_t stacksize;/* if not zero, initial stack size */ |
1535 | }; |
1536 | |
1537 | |
1538 | /* |
1539 | * The source_version_command is an optional load command containing |
1540 | * the version of the sources used to build the binary. |
1541 | */ |
1542 | struct source_version_command { |
1543 | uint32_t cmd; /* LC_SOURCE_VERSION */ |
1544 | uint32_t cmdsize; /* 16 */ |
1545 | uint64_t version; /* A.B.C.D.E packed as a24.b10.c10.d10.e10 */ |
1546 | }; |
1547 | |
1548 | |
1549 | /* |
1550 | * The LC_DATA_IN_CODE load commands uses a linkedit_data_command |
1551 | * to point to an array of data_in_code_entry entries. Each entry |
1552 | * describes a range of data in a code section. |
1553 | */ |
1554 | struct data_in_code_entry { |
1555 | uint32_t offset; /* from mach_header to start of data range*/ |
1556 | uint16_t length; /* number of bytes in data range */ |
1557 | uint16_t kind; /* a DICE_KIND_* value */ |
1558 | }; |
1559 | #define DICE_KIND_DATA 0x0001 |
1560 | #define DICE_KIND_JUMP_TABLE8 0x0002 |
1561 | #define DICE_KIND_JUMP_TABLE16 0x0003 |
1562 | #define DICE_KIND_JUMP_TABLE32 0x0004 |
1563 | #define DICE_KIND_ABS_JUMP_TABLE32 0x0005 |
1564 | |
1565 | |
1566 | |
1567 | /* |
1568 | * Sections of type S_THREAD_LOCAL_VARIABLES contain an array |
1569 | * of tlv_descriptor structures. |
1570 | */ |
1571 | struct tlv_descriptor |
1572 | { |
1573 | void* (*thunk)(struct tlv_descriptor*); |
1574 | unsigned long key; |
1575 | unsigned long offset; |
1576 | }; |
1577 | |
1578 | /* |
1579 | * LC_NOTE commands describe a region of arbitrary data included in a Mach-O |
1580 | * file. Its initial use is to record extra data in MH_CORE files. |
1581 | */ |
1582 | struct note_command { |
1583 | uint32_t cmd; /* LC_NOTE */ |
1584 | uint32_t cmdsize; /* sizeof(struct note_command) */ |
1585 | char data_owner[16]; /* owner name for this LC_NOTE */ |
1586 | uint64_t offset; /* file offset of this data */ |
1587 | uint64_t size; /* length of data region */ |
1588 | }; |
1589 | |
1590 | #endif /* _MACHO_LOADER_H_ */ |
1591 | |