![[BACK]](/cvsweb/icons/back.gif){kind=icon}
Return to loader.h CVS log ![[TXT]](/cvsweb/icons/text.gif){kind=icon}
![[DIR]](/cvsweb/icons/dir.gif){kind=icon}
Up to [Apple XNU] / XNU / EXTERNAL_HEADERS / mach-o|
Return to loader.h CVS log | Up to [Apple XNU] / XNU / EXTERNAL_HEADERS / mach-o |
1.1 ! root 1: /* ! 2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved. ! 3: * ! 4: * @APPLE_LICENSE_HEADER_START@ ! 5: * ! 6: * The contents of this file constitute Original Code as defined in and ! 7: * are subject to the Apple Public Source License Version 1.1 (the ! 8: * "License"). You may not use this file except in compliance with the ! 9: * License. Please obtain a copy of the License at ! 10: * http://www.apple.com/publicsource and read it before using this file. ! 11: * ! 12: * This Original Code and all software distributed under the License are ! 13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER ! 14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, ! 15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, ! 16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the ! 17: * License for the specific language governing rights and limitations ! 18: * under the License. ! 19: * ! 20: * @APPLE_LICENSE_HEADER_END@ ! 21: */ ! 22: #ifndef _MACHO_LOADER_H_ ! 23: #define _MACHO_LOADER_H_ ! 24: ! 25: /* ! 26: * This file describes the format of mach object files. ! 27: */ ! 28: ! 29: /* ! 30: * <mach/machine.h> is needed here for the cpu_type_t and cpu_subtype_t types ! 31: * and contains the constants for the possible values of these types. ! 32: */ ! 33: #import <mach/machine.h> ! 34: ! 35: /* ! 36: * <mach/vm_prot.h> is needed here for the vm_prot_t type and contains the ! 37: * constants that are or'ed together for the possible values of this type. ! 38: */ ! 39: #import <mach/vm_prot.h> ! 40: ! 41: /* ! 42: * <machine/thread_status.h> is expected to define the flavors of the thread ! 43: * states and the structures of those flavors for each machine. ! 44: */ ! 45: #import <mach/machine/thread_status.h> ! 46: #import <architecture/byte_order.h> ! 47: ! 48: /* ! 49: * The mach header appears at the very beginning of the object file. ! 50: */ ! 51: struct mach_header { ! 52: unsigned long magic; /* mach magic number identifier */ ! 53: cpu_type_t cputype; /* cpu specifier */ ! 54: cpu_subtype_t cpusubtype; /* machine specifier */ ! 55: unsigned long filetype; /* type of file */ ! 56: unsigned long ncmds; /* number of load commands */ ! 57: unsigned long sizeofcmds; /* the size of all the load commands */ ! 58: unsigned long flags; /* flags */ ! 59: }; ! 60: ! 61: /* Constant for the magic field of the mach_header */ ! 62: #define MH_MAGIC 0xfeedface /* the mach magic number */ ! 63: #define MH_CIGAM NXSwapInt(MH_MAGIC) ! 64: ! 65: /* ! 66: * The layout of the file depends on the filetype. For all but the MH_OBJECT ! 67: * file type the segments are padded out and aligned on a segment alignment ! 68: * boundary for efficient demand pageing. The MH_EXECUTE, MH_FVMLIB, MH_DYLIB, ! 69: * MH_DYLINKER and MH_BUNDLE file types also have the headers included as part ! 70: * of their first segment. ! 71: * ! 72: * The file type MH_OBJECT is a compact format intended as output of the ! 73: * assembler and input (and possibly output) of the link editor (the .o ! 74: * format). All sections are in one unnamed segment with no segment padding. ! 75: * This format is used as an executable format when the file is so small the ! 76: * segment padding greatly increases it's size. ! 77: * ! 78: * The file type MH_PRELOAD is an executable format intended for things that ! 79: * not executed under the kernel (proms, stand alones, kernels, etc). The ! 80: * format can be executed under the kernel but may demand paged it and not ! 81: * preload it before execution. ! 82: * ! 83: * A core file is in MH_CORE format and can be any in an arbritray legal ! 84: * Mach-O file. ! 85: * ! 86: * Constants for the filetype field of the mach_header ! 87: */ ! 88: #define MH_OBJECT 0x1 /* relocatable object file */ ! 89: #define MH_EXECUTE 0x2 /* demand paged executable file */ ! 90: #define MH_FVMLIB 0x3 /* fixed VM shared library file */ ! 91: #define MH_CORE 0x4 /* core file */ ! 92: #define MH_PRELOAD 0x5 /* preloaded executable file */ ! 93: #define MH_DYLIB 0x6 /* dynamicly bound shared library file*/ ! 94: #define MH_DYLINKER 0x7 /* dynamic link editor */ ! 95: #define MH_BUNDLE 0x8 /* dynamicly bound bundle file */ ! 96: ! 97: /* Constants for the flags field of the mach_header */ ! 98: #define MH_NOUNDEFS 0x1 /* the object file has no undefined ! 99: references, can be executed */ ! 100: #define MH_INCRLINK 0x2 /* the object file is the output of an ! 101: incremental link against a base file ! 102: and can't be link edited again */ ! 103: #define MH_DYLDLINK 0x4 /* the object file is input for the ! 104: dynamic linker and can't be staticly ! 105: link edited again */ ! 106: #define MH_BINDATLOAD 0x8 /* the object file's undefined ! 107: references are bound by the dynamic ! 108: linker when loaded. */ ! 109: #define MH_PREBOUND 0x10 /* the file has it's dynamic undefined ! 110: references prebound. */ ! 111: ! 112: /* ! 113: * The load commands directly follow the mach_header. The total size of all ! 114: * of the commands is given by the sizeofcmds field in the mach_header. All ! 115: * load commands must have as their first two fields cmd and cmdsize. The cmd ! 116: * field is filled in with a constant for that command type. Each command type ! 117: * has a structure specifically for it. The cmdsize field is the size in bytes ! 118: * of the particular load command structure plus anything that follows it that ! 119: * is a part of the load command (i.e. section structures, strings, etc.). To ! 120: * advance to the next load command the cmdsize can be added to the offset or ! 121: * pointer of the current load command. The cmdsize MUST be a multiple of ! 122: * sizeof(long) (this is forever the maximum alignment of any load commands). ! 123: * The padded bytes must be zero. All tables in the object file must also ! 124: * follow these rules so the file can be memory mapped. Otherwise the pointers ! 125: * to these tables will not work well or at all on some machines. With all ! 126: * padding zeroed like objects will compare byte for byte. ! 127: */ ! 128: struct load_command { ! 129: unsigned long cmd; /* type of load command */ ! 130: unsigned long cmdsize; /* total size of command in bytes */ ! 131: }; ! 132: ! 133: /* Constants for the cmd field of all load commands, the type */ ! 134: #define LC_SEGMENT 0x1 /* segment of this file to be mapped */ ! 135: #define LC_SYMTAB 0x2 /* link-edit stab symbol table info */ ! 136: #define LC_SYMSEG 0x3 /* link-edit gdb symbol table info (obsolete) */ ! 137: #define LC_THREAD 0x4 /* thread */ ! 138: #define LC_UNIXTHREAD 0x5 /* unix thread (includes a stack) */ ! 139: #define LC_LOADFVMLIB 0x6 /* load a specified fixed VM shared library */ ! 140: #define LC_IDFVMLIB 0x7 /* fixed VM shared library identification */ ! 141: #define LC_IDENT 0x8 /* object identification info (obsolete) */ ! 142: #define LC_FVMFILE 0x9 /* fixed VM file inclusion (internal use) */ ! 143: #define LC_PREPAGE 0xa /* prepage command (internal use) */ ! 144: #define LC_DYSYMTAB 0xb /* dynamic link-edit symbol table info */ ! 145: #define LC_LOAD_DYLIB 0xc /* load a dynamicly linked shared library */ ! 146: #define LC_ID_DYLIB 0xd /* dynamicly linked shared lib identification */ ! 147: #define LC_LOAD_DYLINKER 0xe /* load a dynamic linker */ ! 148: #define LC_ID_DYLINKER 0xf /* dynamic linker identification */ ! 149: #define LC_PREBOUND_DYLIB 0x10 /* modules prebound for a dynamicly */ ! 150: /* linked shared library */ ! 151: ! 152: /* ! 153: * A variable length string in a load command is represented by an lc_str ! 154: * union. The strings are stored just after the load command structure and ! 155: * the offset is from the start of the load command structure. The size ! 156: * of the string is reflected in the cmdsize field of the load command. ! 157: * Once again any padded bytes to bring the cmdsize field to a multiple ! 158: * of sizeof(long) must be zero. ! 159: */ ! 160: union lc_str { ! 161: unsigned long offset; /* offset to the string */ ! 162: char *ptr; /* pointer to the string */ ! 163: }; ! 164: ! 165: /* ! 166: * The segment load command indicates that a part of this file is to be ! 167: * mapped into the task's address space. The size of this segment in memory, ! 168: * vmsize, maybe equal to or larger than the amount to map from this file, ! 169: * filesize. The file is mapped starting at fileoff to the beginning of ! 170: * the segment in memory, vmaddr. The rest of the memory of the segment, ! 171: * if any, is allocated zero fill on demand. The segment's maximum virtual ! 172: * memory protection and initial virtual memory protection are specified ! 173: * by the maxprot and initprot fields. If the segment has sections then the ! 174: * section structures directly follow the segment command and their size is ! 175: * reflected in cmdsize. ! 176: */ ! 177: struct segment_command { ! 178: unsigned long cmd; /* LC_SEGMENT */ ! 179: unsigned long cmdsize; /* includes sizeof section structs */ ! 180: char segname[16]; /* segment name */ ! 181: unsigned long vmaddr; /* memory address of this segment */ ! 182: unsigned long vmsize; /* memory size of this segment */ ! 183: unsigned long fileoff; /* file offset of this segment */ ! 184: unsigned long filesize; /* amount to map from the file */ ! 185: vm_prot_t maxprot; /* maximum VM protection */ ! 186: vm_prot_t initprot; /* initial VM protection */ ! 187: unsigned long nsects; /* number of sections in segment */ ! 188: unsigned long flags; /* flags */ ! 189: }; ! 190: ! 191: /* Constants for the flags field of the segment_command */ ! 192: #define SG_HIGHVM 0x1 /* the file contents for this segment is for ! 193: the high part of the VM space, the low part ! 194: is zero filled (for stacks in core files) */ ! 195: #define SG_FVMLIB 0x2 /* this segment is the VM that is allocated by ! 196: a fixed VM library, for overlap checking in ! 197: the link editor */ ! 198: #define SG_NORELOC 0x4 /* this segment has nothing that was relocated ! 199: in it and nothing relocated to it, that is ! 200: it maybe safely replaced without relocation*/ ! 201: ! 202: /* ! 203: * A segment is made up of zero or more sections. Non-MH_OBJECT files have ! 204: * all of their segments with the proper sections in each, and padded to the ! 205: * specified segment alignment when produced by the link editor. The first ! 206: * segment of a MH_EXECUTE and MH_FVMLIB format file contains the mach_header ! 207: * and load commands of the object file before it's first section. The zero ! 208: * fill sections are always last in their segment (in all formats). This ! 209: * allows the zeroed segment padding to be mapped into memory where zero fill ! 210: * sections might be. ! 211: * ! 212: * The MH_OBJECT format has all of it's sections in one segment for ! 213: * compactness. There is no padding to a specified segment boundary and the ! 214: * mach_header and load commands are not part of the segment. ! 215: * ! 216: * Sections with the same section name, sectname, going into the same segment, ! 217: * segname, are combined by the link editor. The resulting section is aligned ! 218: * to the maximum alignment of the combined sections and is the new section's ! 219: * alignment. The combined sections are aligned to their original alignment in ! 220: * the combined section. Any padded bytes to get the specified alignment are ! 221: * zeroed. ! 222: * ! 223: * The format of the relocation entries referenced by the reloff and nreloc ! 224: * fields of the section structure for mach object files is described in the ! 225: * header file <reloc.h>. ! 226: */ ! 227: struct section { ! 228: char sectname[16]; /* name of this section */ ! 229: char segname[16]; /* segment this section goes in */ ! 230: unsigned long addr; /* memory address of this section */ ! 231: unsigned long size; /* size in bytes of this section */ ! 232: unsigned long offset; /* file offset of this section */ ! 233: unsigned long align; /* section alignment (power of 2) */ ! 234: unsigned long reloff; /* file offset of relocation entries */ ! 235: unsigned long nreloc; /* number of relocation entries */ ! 236: unsigned long flags; /* flags (section type and attributes)*/ ! 237: unsigned long reserved1; /* reserved */ ! 238: unsigned long reserved2; /* reserved */ ! 239: }; ! 240: ! 241: /* ! 242: * The flags field of a section structure is separated into two parts a section ! 243: * type and section attributes. The section types are mutually exclusive (it ! 244: * can only have one type) but the section attributes are not (it may have more ! 245: * than one attribute). ! 246: */ ! 247: #define SECTION_TYPE 0x000000ff /* 256 section types */ ! 248: #define SECTION_ATTRIBUTES 0xffffff00 /* 24 section attributes */ ! 249: ! 250: /* Constants for the type of a section */ ! 251: #define S_REGULAR 0x0 /* regular section */ ! 252: #define S_ZEROFILL 0x1 /* zero fill on demand section */ ! 253: #define S_CSTRING_LITERALS 0x2 /* section with only literal C strings*/ ! 254: #define S_4BYTE_LITERALS 0x3 /* section with only 4 byte literals */ ! 255: #define S_8BYTE_LITERALS 0x4 /* section with only 8 byte literals */ ! 256: #define S_LITERAL_POINTERS 0x5 /* section with only pointers to */ ! 257: /* literals */ ! 258: /* ! 259: * For the two types of symbol pointers sections and the symbol stubs section ! 260: * they have indirect symbol table entries. For each of the entries in the ! 261: * section the indirect symbol table entries, in corresponding order in the ! 262: * indirect symbol table, start at the index stored in the reserved1 field ! 263: * of the section structure. Since the indirect symbol table entries ! 264: * correspond to the entries in the section the number of indirect symbol table ! 265: * entries is inferred from the size of the section divided by the size of the ! 266: * entries in the section. For symbol pointers sections the size of the entries ! 267: * in the section is 4 bytes and for symbol stubs sections the byte size of the ! 268: * stubs is stored in the reserved2 field of the section structure. ! 269: */ ! 270: #define S_NON_LAZY_SYMBOL_POINTERS 0x6 /* section with only non-lazy ! 271: symbol pointers */ ! 272: #define S_LAZY_SYMBOL_POINTERS 0x7 /* section with only lazy symbol ! 273: pointers */ ! 274: #define S_SYMBOL_STUBS 0x8 /* section with only symbol ! 275: stubs, byte size of stub in ! 276: the reserved2 field */ ! 277: #define S_MOD_INIT_FUNC_POINTERS 0x9 /* section with only function ! 278: pointers for initialization*/ ! 279: /* ! 280: * Constants for the section attributes part of the flags field of a section ! 281: * structure. ! 282: */ ! 283: #define SECTION_ATTRIBUTES_USR 0xff000000 /* User setable attributes */ ! 284: #define S_ATTR_PURE_INSTRUCTIONS 0x80000000 /* section contains only true ! 285: machine instructions */ ! 286: #define SECTION_ATTRIBUTES_SYS 0x00ffff00 /* system setable attributes */ ! 287: #define S_ATTR_SOME_INSTRUCTIONS 0x00000400 /* section contains some ! 288: machine instructions */ ! 289: #define S_ATTR_EXT_RELOC 0x00000200 /* section has external ! 290: relocation entries */ ! 291: #define S_ATTR_LOC_RELOC 0x00000100 /* section has local ! 292: relocation entries */ ! 293: ! 294: ! 295: /* ! 296: * The names of segments and sections in them are mostly meaningless to the ! 297: * link-editor. But there are few things to support traditional UNIX ! 298: * executables that require the link-editor and assembler to use some names ! 299: * agreed upon by convention. ! 300: * ! 301: * The initial protection of the "__TEXT" segment has write protection turned ! 302: * off (not writeable). ! 303: * ! 304: * The link-editor will allocate common symbols at the end of the "__common" ! 305: * section in the "__DATA" segment. It will create the section and segment ! 306: * if needed. ! 307: */ ! 308: ! 309: /* The currently known segment names and the section names in those segments */ ! 310: ! 311: #define SEG_PAGEZERO "__PAGEZERO" /* the pagezero segment which has no */ ! 312: /* protections and catches NULL */ ! 313: /* references for MH_EXECUTE files */ ! 314: ! 315: ! 316: #define SEG_TEXT "__TEXT" /* the tradition UNIX text segment */ ! 317: #define SECT_TEXT "__text" /* the real text part of the text */ ! 318: /* section no headers, and no padding */ ! 319: #define SECT_FVMLIB_INIT0 "__fvmlib_init0" /* the fvmlib initialization */ ! 320: /* section */ ! 321: #define SECT_FVMLIB_INIT1 "__fvmlib_init1" /* the section following the */ ! 322: /* fvmlib initialization */ ! 323: /* section */ ! 324: ! 325: #define SEG_DATA "__DATA" /* the tradition UNIX data segment */ ! 326: #define SECT_DATA "__data" /* the real initialized data section */ ! 327: /* no padding, no bss overlap */ ! 328: #define SECT_BSS "__bss" /* the real uninitialized data section*/ ! 329: /* no padding */ ! 330: #define SECT_COMMON "__common" /* the section common symbols are */ ! 331: /* allocated in by the link editor */ ! 332: ! 333: #define SEG_OBJC "__OBJC" /* objective-C runtime segment */ ! 334: #define SECT_OBJC_SYMBOLS "__symbol_table" /* symbol table */ ! 335: #define SECT_OBJC_MODULES "__module_info" /* module information */ ! 336: #define SECT_OBJC_STRINGS "__selector_strs" /* string table */ ! 337: #define SECT_OBJC_REFS "__selector_refs" /* string table */ ! 338: ! 339: #define SEG_ICON "__ICON" /* the NeXT icon segment */ ! 340: #define SECT_ICON_HEADER "__header" /* the icon headers */ ! 341: #define SECT_ICON_TIFF "__tiff" /* the icons in tiff format */ ! 342: ! 343: #define SEG_LINKEDIT "__LINKEDIT" /* the segment containing all structs */ ! 344: /* created and maintained by the link */ ! 345: /* editor. Created with -seglinkedit */ ! 346: /* option to ld(1) for MH_EXECUTE and */ ! 347: /* FVMLIB file types only */ ! 348: ! 349: #define SEG_UNIXSTACK "__UNIXSTACK" /* the unix stack segment */ ! 350: ! 351: /* ! 352: * Fixed virtual memory shared libraries are identified by two things. The ! 353: * target pathname (the name of the library as found for execution), and the ! 354: * minor version number. The address of where the headers are loaded is in ! 355: * header_addr. ! 356: */ ! 357: struct fvmlib { ! 358: union lc_str name; /* library's target pathname */ ! 359: unsigned long minor_version; /* library's minor version number */ ! 360: unsigned long header_addr; /* library's header address */ ! 361: }; ! 362: ! 363: /* ! 364: * A fixed virtual shared library (filetype == MH_FVMLIB in the mach header) ! 365: * contains a fvmlib_command (cmd == LC_IDFVMLIB) to identify the library. ! 366: * An object that uses a fixed virtual shared library also contains a ! 367: * fvmlib_command (cmd == LC_LOADFVMLIB) for each library it uses. ! 368: */ ! 369: struct fvmlib_command { ! 370: unsigned long cmd; /* LC_IDFVMLIB or LC_LOADFVMLIB */ ! 371: unsigned long cmdsize; /* includes pathname string */ ! 372: struct fvmlib fvmlib; /* the library identification */ ! 373: }; ! 374: ! 375: /* ! 376: * Dynamicly linked shared libraries are identified by two things. The ! 377: * pathname (the name of the library as found for execution), and the ! 378: * compatibility version number. The pathname must match and the compatibility ! 379: * number in the user of the library must be greater than or equal to the ! 380: * library being used. The time stamp is used to record the time a library was ! 381: * built and copied into user so it can be use to determined if the library used ! 382: * at runtime is exactly the same as used to built the program. ! 383: */ ! 384: struct dylib { ! 385: union lc_str name; /* library's path name */ ! 386: unsigned long timestamp; /* library's build time stamp */ ! 387: unsigned long current_version; /* library's current version number */ ! 388: unsigned long compatibility_version;/* library's compatibility vers number*/ ! 389: }; ! 390: ! 391: /* ! 392: * A dynamicly linked shared library (filetype == MH_DYLIB in the mach header) ! 393: * contains a dylib_command (cmd == LC_ID_DYLIB) to identify the library. ! 394: * An object that uses a dynamicly linked shared library also contains a ! 395: * dylib_command (cmd == LC_LOAD_DYLIB) for each library it uses. ! 396: */ ! 397: struct dylib_command { ! 398: unsigned long cmd; /* LC_ID_DYLIB or LC_LOAD_DYLIB */ ! 399: unsigned long cmdsize; /* includes pathname string */ ! 400: struct dylib dylib; /* the library identification */ ! 401: }; ! 402: ! 403: /* ! 404: * A program (filetype == MH_EXECUTE) or bundle (filetype == MH_BUNDLE) that is ! 405: * prebound to it's dynamic libraries has one of these for each library that ! 406: * the static linker used in prebinding. It contains a bit vector for the ! 407: * modules in the library. The bits indicate which modules are bound (1) and ! 408: * which are not (0) from the library. The bit for module 0 is the low bit ! 409: * of the first byte. So the bit for the Nth module is: ! 410: * (linked_modules[N/8] >> N%8) & 1 ! 411: */ ! 412: struct prebound_dylib_command { ! 413: unsigned long cmd; /* LC_PREBOUND_DYLIB */ ! 414: unsigned long cmdsize; /* includes strings */ ! 415: union lc_str name; /* library's path name */ ! 416: unsigned long nmodules; /* number of modules in library */ ! 417: union lc_str linked_modules; /* bit vector of linked modules */ ! 418: }; ! 419: ! 420: /* ! 421: * A program that uses a dynamic linker contains a dylinker_command to identify ! 422: * the name of the dynamic linker (LC_LOAD_DYLINKER). And a dynamic linker ! 423: * contains a dylinker_command to identify the dynamic linker (LC_ID_DYLINKER). ! 424: * A file can have at most one of these. ! 425: */ ! 426: struct dylinker_command { ! 427: unsigned long cmd; /* LC_ID_DYLINKER or LC_LOAD_DYLINKER */ ! 428: unsigned long cmdsize; /* includes pathname string */ ! 429: union lc_str name; /* dynamic linker's path name */ ! 430: }; ! 431: ! 432: /* ! 433: * Thread commands contain machine-specific data structures suitable for ! 434: * use in the thread state primitives. The machine specific data structures ! 435: * follow the struct thread_command as follows. ! 436: * Each flavor of machine specific data structure is preceded by an unsigned ! 437: * long constant for the flavor of that data structure, an unsigned long ! 438: * that is the count of longs of the size of the state data structure and then ! 439: * the state data structure follows. This triple may be repeated for many ! 440: * flavors. The constants for the flavors, counts and state data structure ! 441: * definitions are expected to be in the header file <machine/thread_status.h>. ! 442: * These machine specific data structures sizes must be multiples of ! 443: * sizeof(long). The cmdsize reflects the total size of the thread_command ! 444: * and all of the sizes of the constants for the flavors, counts and state ! 445: * data structures. ! 446: * ! 447: * For executable objects that are unix processes there will be one ! 448: * thread_command (cmd == LC_UNIXTHREAD) created for it by the link-editor. ! 449: * This is the same as a LC_THREAD, except that a stack is automatically ! 450: * created (based on the shell's limit for the stack size). Command arguments ! 451: * and environment variables are copied onto that stack. ! 452: */ ! 453: struct thread_command { ! 454: unsigned long cmd; /* LC_THREAD or LC_UNIXTHREAD */ ! 455: unsigned long cmdsize; /* total size of this command */ ! 456: /* unsigned long flavor flavor of thread state */ ! 457: /* unsigned long count count of longs in thread state */ ! 458: /* struct XXX_thread_state state thread state for this flavor */ ! 459: /* ... */ ! 460: }; ! 461: ! 462: /* ! 463: * The symtab_command contains the offsets and sizes of the link-edit 4.3BSD ! 464: * "stab" style symbol table information as described in the header files ! 465: * <nlist.h> and <stab.h>. ! 466: */ ! 467: struct symtab_command { ! 468: unsigned long cmd; /* LC_SYMTAB */ ! 469: unsigned long cmdsize; /* sizeof(struct symtab_command) */ ! 470: unsigned long symoff; /* symbol table offset */ ! 471: unsigned long nsyms; /* number of symbol table entries */ ! 472: unsigned long stroff; /* string table offset */ ! 473: unsigned long strsize; /* string table size in bytes */ ! 474: }; ! 475: ! 476: /* ! 477: * This is the second set of the symbolic information which is used to support ! 478: * the data structures for the dynamicly link editor. ! 479: * ! 480: * The original set of symbolic information in the symtab_command which contains ! 481: * the symbol and string tables must also be present when this load command is ! 482: * present. When this load command is present the symbol table is organized ! 483: * into three groups of symbols: ! 484: * local symbols (static and debugging symbols) - grouped by module ! 485: * defined external symbols - grouped by module (sorted by name if not lib) ! 486: * undefined external symbols (sorted by name) ! 487: * In this load command there are offsets and counts to each of the three groups ! 488: * of symbols. ! 489: * ! 490: * This load command contains a the offsets and sizes of the following new ! 491: * symbolic information tables: ! 492: * table of contents ! 493: * module table ! 494: * reference symbol table ! 495: * indirect symbol table ! 496: * The first three tables above (the table of contents, module table and ! 497: * reference symbol table) are only present if the file is a dynamicly linked ! 498: * shared library. For executable and object modules, which are files ! 499: * containing only one module, the information that would be in these three ! 500: * tables is determined as follows: ! 501: * table of contents - the defined external symbols are sorted by name ! 502: * module table - the file contains only one module so everything in the ! 503: * file is part of the module. ! 504: * reference symbol table - is the defined and undefined external symbols ! 505: * ! 506: * For dynamicly linked shared library files this load command also contains ! 507: * offsets and sizes to the pool of relocation entries for all sections ! 508: * separated into two groups: ! 509: * external relocation entries ! 510: * local relocation entries ! 511: * For executable and object modules the relocation entries continue to hang ! 512: * off the section structures. ! 513: */ ! 514: struct dysymtab_command { ! 515: unsigned long cmd; /* LC_DYSYMTAB */ ! 516: unsigned long cmdsize; /* sizeof(struct dysymtab_command) */ ! 517: ! 518: /* ! 519: * The symbols indicated by symoff and nsyms of the LC_SYMTAB load command ! 520: * are grouped into the following three groups: ! 521: * local symbols (further grouped by the module they are from) ! 522: * defined external symbols (further grouped by the module they are from) ! 523: * undefined symbols ! 524: * ! 525: * The local symbols are used only for debugging. The dynamic binding ! 526: * process may have to use them to indicate to the debugger the local ! 527: * symbols for a module that is being bound. ! 528: * ! 529: * The last two groups are used by the dynamic binding process to do the ! 530: * binding (indirectly through the module table and the reference symbol ! 531: * table when this is a dynamicly linked shared library file). ! 532: */ ! 533: unsigned long ilocalsym; /* index to local symbols */ ! 534: unsigned long nlocalsym; /* number of local symbols */ ! 535: ! 536: unsigned long iextdefsym; /* index to externally defined symbols */ ! 537: unsigned long nextdefsym; /* number of externally defined symbols */ ! 538: ! 539: unsigned long iundefsym; /* index to undefined symbols */ ! 540: unsigned long nundefsym; /* number of undefined symbols */ ! 541: ! 542: /* ! 543: * For the for the dynamic binding process to find which module a symbol ! 544: * is defined in the table of contents is used (analogous to the ranlib ! 545: * structure in an archive) which maps defined external symbols to modules ! 546: * they are defined in. This exists only in a dynamicly linked shared ! 547: * library file. For executable and object modules the defined external ! 548: * symbols are sorted by name and is use as the table of contents. ! 549: */ ! 550: unsigned long tocoff; /* file offset to table of contents */ ! 551: unsigned long ntoc; /* number of entries in table of contents */ ! 552: ! 553: /* ! 554: * To support dynamic binding of "modules" (whole object files) the symbol ! 555: * table must reflect the modules that the file was created from. This is ! 556: * done by having a module table that has indexes and counts into the merged ! 557: * tables for each module. The module structure that these two entries ! 558: * refer to is described below. This exists only in a dynamicly linked ! 559: * shared library file. For executable and object modules the file only ! 560: * contains one module so everything in the file belongs to the module. ! 561: */ ! 562: unsigned long modtaboff; /* file offset to module table */ ! 563: unsigned long nmodtab; /* number of module table entries */ ! 564: ! 565: /* ! 566: * To support dynamic module binding the module structure for each module ! 567: * indicates the external references (defined and undefined) each module ! 568: * makes. For each module there is an offset and a count into the ! 569: * reference symbol table for the symbols that the module references. ! 570: * This exists only in a dynamicly linked shared library file. For ! 571: * executable and object modules the defined external symbols and the ! 572: * undefined external symbols indicates the external references. ! 573: */ ! 574: unsigned long extrefsymoff; /* offset to referenced symbol table */ ! 575: unsigned long nextrefsyms; /* number of referenced symbol table entries */ ! 576: ! 577: /* ! 578: * The sections that contain "symbol pointers" and "routine stubs" have ! 579: * indexes and (implied counts based on the size of the section and fixed ! 580: * size of the entry) into the "indirect symbol" table for each pointer ! 581: * and stub. For every section of these two types the index into the ! 582: * indirect symbol table is stored in the section header in the field ! 583: * reserved1. An indirect symbol table entry is simply a 32bit index into ! 584: * the symbol table to the symbol that the pointer or stub is referring to. ! 585: * The indirect symbol table is ordered to match the entries in the section. ! 586: */ ! 587: unsigned long indirectsymoff; /* file offset to the indirect symbol table */ ! 588: unsigned long nindirectsyms; /* number of indirect symbol table entries */ ! 589: ! 590: /* ! 591: * To support relocating an individual module in a library file quickly the ! 592: * external relocation entries for each module in the library need to be ! 593: * accessed efficiently. Since the relocation entries can't be accessed ! 594: * through the section headers for a library file they are separated into ! 595: * groups of local and external entries further grouped by module. In this ! 596: * case the presents of this load command who's extreloff, nextrel, ! 597: * locreloff and nlocrel fields are non-zero indicates that the relocation ! 598: * entries of non-merged sections are not referenced through the section ! 599: * structures (and the reloff and nreloc fields in the section headers are ! 600: * set to zero). ! 601: * ! 602: * Since the relocation entries are not accessed through the section headers ! 603: * this requires the r_address field to be something other than a section ! 604: * offset to identify the item to be relocated. In this case r_address is ! 605: * set to the offset from the vmaddr of the first LC_SEGMENT command. ! 606: * ! 607: * The relocation entries are grouped by module and the module table ! 608: * entries have indexes and counts into them for the group of external ! 609: * relocation entries for that the module. ! 610: * ! 611: * For sections that are merged across modules there must not be any ! 612: * remaining external relocation entries for them (for merged sections ! 613: * remaining relocation entries must be local). ! 614: */ ! 615: unsigned long extreloff; /* offset to external relocation entries */ ! 616: unsigned long nextrel; /* number of external relocation entries */ ! 617: ! 618: /* ! 619: * All the local relocation entries are grouped together (they are not ! 620: * grouped by their module since they are only used if the object is moved ! 621: * from it staticly link edited address). ! 622: */ ! 623: unsigned long locreloff; /* offset to local relocation entries */ ! 624: unsigned long nlocrel; /* number of local relocation entries */ ! 625: ! 626: }; ! 627: ! 628: /* ! 629: * An indirect symbol table entry is simply a 32bit index into the symbol table ! 630: * to the symbol that the pointer or stub is refering to. Unless it is for a ! 631: * non-lazy symbol pointer section for a defined symbol which strip(1) as ! 632: * removed. In which case it has the value INDIRECT_SYMBOL_LOCAL. If the ! 633: * symbol was also absolute INDIRECT_SYMBOL_ABS is or'ed with that. ! 634: */ ! 635: #define INDIRECT_SYMBOL_LOCAL 0x80000000 ! 636: #define INDIRECT_SYMBOL_ABS 0x40000000 ! 637: ! 638: ! 639: /* a table of contents entry */ ! 640: struct dylib_table_of_contents { ! 641: unsigned long symbol_index; /* the defined external symbol ! 642: (index into the symbol table) */ ! 643: unsigned long module_index; /* index into the module table this symbol ! 644: is defined in */ ! 645: }; ! 646: ! 647: /* a module table entry */ ! 648: struct dylib_module { ! 649: unsigned long module_name; /* the module name (index into string table) */ ! 650: ! 651: unsigned long iextdefsym; /* index into externally defined symbols */ ! 652: unsigned long nextdefsym; /* number of externally defined symbols */ ! 653: unsigned long irefsym; /* index into reference symbol table */ ! 654: unsigned long nrefsym; /* number of reference symbol table entries */ ! 655: unsigned long ilocalsym; /* index into symbols for local symbols */ ! 656: unsigned long nlocalsym; /* number of local symbols */ ! 657: ! 658: unsigned long iextrel; /* index into external relocation entries */ ! 659: unsigned long nextrel; /* number of external relocation entries */ ! 660: ! 661: unsigned long iinit; /* index into the init section */ ! 662: unsigned long ninit; /* number of init section entries */ ! 663: ! 664: unsigned long /* for this module address of the start of */ ! 665: objc_module_info_addr; /* the (__OBJC,__module_info) section */ ! 666: unsigned long /* for this module size of */ ! 667: objc_module_info_size; /* the (__OBJC,__module_info) section */ ! 668: }; ! 669: ! 670: /* ! 671: * The entries in the reference symbol table are used when loading the module ! 672: * (both by the static and dynamic link editors) and if the module is unloaded ! 673: * or replaced. Therefore all external symbols (defined and undefined) are ! 674: * listed in the module's reference table. The flags describe the type of ! 675: * reference that is being made. The constants for the flags are defined in ! 676: * <mach-o/nlist.h> as they are also used for symbol table entries. ! 677: */ ! 678: struct dylib_reference { ! 679: unsigned long isym:24, /* index into the symbol table */ ! 680: flags:8; /* flags to indicate the type of reference */ ! 681: }; ! 682: ! 683: /* ! 684: * The symseg_command contains the offset and size of the GNU style ! 685: * symbol table information as described in the header file <symseg.h>. ! 686: * The symbol roots of the symbol segments must also be aligned properly ! 687: * in the file. So the requirement of keeping the offsets aligned to a ! 688: * multiple of a sizeof(long) translates to the length field of the symbol ! 689: * roots also being a multiple of a long. Also the padding must again be ! 690: * zeroed. (THIS IS OBSOLETE and no longer supported). ! 691: */ ! 692: struct symseg_command { ! 693: unsigned long cmd; /* LC_SYMSEG */ ! 694: unsigned long cmdsize; /* sizeof(struct symseg_command) */ ! 695: unsigned long offset; /* symbol segment offset */ ! 696: unsigned long size; /* symbol segment size in bytes */ ! 697: }; ! 698: ! 699: /* ! 700: * The ident_command contains a free format string table following the ! 701: * ident_command structure. The strings are null terminated and the size of ! 702: * the command is padded out with zero bytes to a multiple of sizeof(long). ! 703: * (THIS IS OBSOLETE and no longer supported). ! 704: */ ! 705: struct ident_command { ! 706: unsigned long cmd; /* LC_IDENT */ ! 707: unsigned long cmdsize; /* strings that follow this command */ ! 708: }; ! 709: ! 710: /* ! 711: * The fvmfile_command contains a reference to a file to be loaded at the ! 712: * specified virtual address. (Presently, this command is reserved for NeXT ! 713: * internal use. The kernel ignores this command when loading a program into ! 714: * memory). ! 715: */ ! 716: struct fvmfile_command { ! 717: unsigned long cmd; /* LC_FVMFILE */ ! 718: unsigned long cmdsize; /* includes pathname string */ ! 719: union lc_str name; /* files pathname */ ! 720: unsigned long header_addr; /* files virtual address */ ! 721: }; ! 722: ! 723: #endif _MACHO_LOADER_H_
This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.