1 | /* |
2 | * Copyright (c) 1999-2003 Apple Computer, 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_NLIST_H_ |
24 | #define _MACHO_NLIST_H_ |
25 | /* $NetBSD: nlist.h,v 1.5 1994/10/26 00:56:11 cgd Exp $ */ |
26 | |
27 | /*- |
28 | * Copyright (c) 1991, 1993 |
29 | * The Regents of the University of California. All rights reserved. |
30 | * (c) UNIX System Laboratories, Inc. |
31 | * All or some portions of this file are derived from material licensed |
32 | * to the University of California by American Telephone and Telegraph |
33 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
34 | * the permission of UNIX System Laboratories, Inc. |
35 | * |
36 | * Redistribution and use in source and binary forms, with or without |
37 | * modification, are permitted provided that the following conditions |
38 | * are met: |
39 | * 1. Redistributions of source code must retain the above copyright |
40 | * notice, this list of conditions and the following disclaimer. |
41 | * 2. Redistributions in binary form must reproduce the above copyright |
42 | * notice, this list of conditions and the following disclaimer in the |
43 | * documentation and/or other materials provided with the distribution. |
44 | * 3. All advertising materials mentioning features or use of this software |
45 | * must display the following acknowledgement: |
46 | * This product includes software developed by the University of |
47 | * California, Berkeley and its contributors. |
48 | * 4. Neither the name of the University nor the names of its contributors |
49 | * may be used to endorse or promote products derived from this software |
50 | * without specific prior written permission. |
51 | * |
52 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
53 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
54 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
55 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
56 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
57 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
58 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
59 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
60 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
61 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
62 | * SUCH DAMAGE. |
63 | * |
64 | * @(#)nlist.h 8.2 (Berkeley) 1/21/94 |
65 | */ |
66 | #include <stdint.h> |
67 | |
68 | /* |
69 | * Format of a symbol table entry of a Mach-O file for 32-bit architectures. |
70 | * Modified from the BSD format. The modifications from the original format |
71 | * were changing n_other (an unused field) to n_sect and the addition of the |
72 | * N_SECT type. These modifications are required to support symbols in a larger |
73 | * number of sections not just the three sections (text, data and bss) in a BSD |
74 | * file. |
75 | */ |
76 | struct nlist { |
77 | union { |
78 | #ifndef __LP64__ |
79 | char *n_name; /* for use when in-core */ |
80 | #endif |
81 | uint32_t n_strx; /* index into the string table */ |
82 | } n_un; |
83 | uint8_t n_type; /* type flag, see below */ |
84 | uint8_t n_sect; /* section number or NO_SECT */ |
85 | int16_t n_desc; /* see <mach-o/stab.h> */ |
86 | uint32_t n_value; /* value of this symbol (or stab offset) */ |
87 | }; |
88 | |
89 | /* |
90 | * This is the symbol table entry structure for 64-bit architectures. |
91 | */ |
92 | struct nlist_64 { |
93 | union { |
94 | uint32_t n_strx; /* index into the string table */ |
95 | } n_un; |
96 | uint8_t n_type; /* type flag, see below */ |
97 | uint8_t n_sect; /* section number or NO_SECT */ |
98 | uint16_t n_desc; /* see <mach-o/stab.h> */ |
99 | uint64_t n_value; /* value of this symbol (or stab offset) */ |
100 | }; |
101 | |
102 | /* |
103 | * Symbols with a index into the string table of zero (n_un.n_strx == 0) are |
104 | * defined to have a null, "", name. Therefore all string indexes to non null |
105 | * names must not have a zero string index. This is bit historical information |
106 | * that has never been well documented. |
107 | */ |
108 | |
109 | /* |
110 | * The n_type field really contains four fields: |
111 | * unsigned char N_STAB:3, |
112 | * N_PEXT:1, |
113 | * N_TYPE:3, |
114 | * N_EXT:1; |
115 | * which are used via the following masks. |
116 | */ |
117 | #define N_STAB 0xe0 /* if any of these bits set, a symbolic debugging entry */ |
118 | #define N_PEXT 0x10 /* private external symbol bit */ |
119 | #define N_TYPE 0x0e /* mask for the type bits */ |
120 | #define N_EXT 0x01 /* external symbol bit, set for external symbols */ |
121 | |
122 | /* |
123 | * Only symbolic debugging entries have some of the N_STAB bits set and if any |
124 | * of these bits are set then it is a symbolic debugging entry (a stab). In |
125 | * which case then the values of the n_type field (the entire field) are given |
126 | * in <mach-o/stab.h> |
127 | */ |
128 | |
129 | /* |
130 | * Values for N_TYPE bits of the n_type field. |
131 | */ |
132 | #define N_UNDF 0x0 /* undefined, n_sect == NO_SECT */ |
133 | #define N_ABS 0x2 /* absolute, n_sect == NO_SECT */ |
134 | #define N_SECT 0xe /* defined in section number n_sect */ |
135 | #define N_PBUD 0xc /* prebound undefined (defined in a dylib) */ |
136 | #define N_INDR 0xa /* indirect */ |
137 | |
138 | /* |
139 | * If the type is N_INDR then the symbol is defined to be the same as another |
140 | * symbol. In this case the n_value field is an index into the string table |
141 | * of the other symbol's name. When the other symbol is defined then they both |
142 | * take on the defined type and value. |
143 | */ |
144 | |
145 | /* |
146 | * If the type is N_SECT then the n_sect field contains an ordinal of the |
147 | * section the symbol is defined in. The sections are numbered from 1 and |
148 | * refer to sections in order they appear in the load commands for the file |
149 | * they are in. This means the same ordinal may very well refer to different |
150 | * sections in different files. |
151 | * |
152 | * The n_value field for all symbol table entries (including N_STAB's) gets |
153 | * updated by the link editor based on the value of it's n_sect field and where |
154 | * the section n_sect references gets relocated. If the value of the n_sect |
155 | * field is NO_SECT then it's n_value field is not changed by the link editor. |
156 | */ |
157 | #define NO_SECT 0 /* symbol is not in any section */ |
158 | #define MAX_SECT 255 /* 1 thru 255 inclusive */ |
159 | |
160 | /* |
161 | * Common symbols are represented by undefined (N_UNDF) external (N_EXT) types |
162 | * who's values (n_value) are non-zero. In which case the value of the n_value |
163 | * field is the size (in bytes) of the common symbol. The n_sect field is set |
164 | * to NO_SECT. The alignment of a common symbol may be set as a power of 2 |
165 | * between 2^1 and 2^15 as part of the n_desc field using the macros below. If |
166 | * the alignment is not set (a value of zero) then natural alignment based on |
167 | * the size is used. |
168 | */ |
169 | #define GET_COMM_ALIGN(n_desc) (((n_desc) >> 8) & 0x0f) |
170 | #define SET_COMM_ALIGN(n_desc,align) \ |
171 | (n_desc) = (((n_desc) & 0xf0ff) | (((align) & 0x0f) << 8)) |
172 | |
173 | /* |
174 | * To support the lazy binding of undefined symbols in the dynamic link-editor, |
175 | * the undefined symbols in the symbol table (the nlist structures) are marked |
176 | * with the indication if the undefined reference is a lazy reference or |
177 | * non-lazy reference. If both a non-lazy reference and a lazy reference is |
178 | * made to the same symbol the non-lazy reference takes precedence. A reference |
179 | * is lazy only when all references to that symbol are made through a symbol |
180 | * pointer in a lazy symbol pointer section. |
181 | * |
182 | * The implementation of marking nlist structures in the symbol table for |
183 | * undefined symbols will be to use some of the bits of the n_desc field as a |
184 | * reference type. The mask REFERENCE_TYPE will be applied to the n_desc field |
185 | * of an nlist structure for an undefined symbol to determine the type of |
186 | * undefined reference (lazy or non-lazy). |
187 | * |
188 | * The constants for the REFERENCE FLAGS are propagated to the reference table |
189 | * in a shared library file. In that case the constant for a defined symbol, |
190 | * REFERENCE_FLAG_DEFINED, is also used. |
191 | */ |
192 | /* Reference type bits of the n_desc field of undefined symbols */ |
193 | #define REFERENCE_TYPE 0x7 |
194 | /* types of references */ |
195 | #define REFERENCE_FLAG_UNDEFINED_NON_LAZY 0 |
196 | #define REFERENCE_FLAG_UNDEFINED_LAZY 1 |
197 | #define REFERENCE_FLAG_DEFINED 2 |
198 | #define REFERENCE_FLAG_PRIVATE_DEFINED 3 |
199 | #define REFERENCE_FLAG_PRIVATE_UNDEFINED_NON_LAZY 4 |
200 | #define REFERENCE_FLAG_PRIVATE_UNDEFINED_LAZY 5 |
201 | |
202 | /* |
203 | * To simplify stripping of objects that use are used with the dynamic link |
204 | * editor, the static link editor marks the symbols defined an object that are |
205 | * referenced by a dynamicly bound object (dynamic shared libraries, bundles). |
206 | * With this marking strip knows not to strip these symbols. |
207 | */ |
208 | #define REFERENCED_DYNAMICALLY 0x0010 |
209 | |
210 | /* |
211 | * For images created by the static link editor with the -twolevel_namespace |
212 | * option in effect the flags field of the mach header is marked with |
213 | * MH_TWOLEVEL. And the binding of the undefined references of the image are |
214 | * determined by the static link editor. Which library an undefined symbol is |
215 | * bound to is recorded by the static linker in the high 8 bits of the n_desc |
216 | * field using the SET_LIBRARY_ORDINAL macro below. The ordinal recorded |
217 | * references the libraries listed in the Mach-O's LC_LOAD_DYLIB, |
218 | * LC_LOAD_WEAK_DYLIB, LC_REEXPORT_DYLIB, LC_LOAD_UPWARD_DYLIB, and |
219 | * LC_LAZY_LOAD_DYLIB, etc. load commands in the order they appear in the |
220 | * headers. The library ordinals start from 1. |
221 | * For a dynamic library that is built as a two-level namespace image the |
222 | * undefined references from module defined in another use the same nlist struct |
223 | * an in that case SELF_LIBRARY_ORDINAL is used as the library ordinal. For |
224 | * defined symbols in all images they also must have the library ordinal set to |
225 | * SELF_LIBRARY_ORDINAL. The EXECUTABLE_ORDINAL refers to the executable |
226 | * image for references from plugins that refer to the executable that loads |
227 | * them. |
228 | * |
229 | * The DYNAMIC_LOOKUP_ORDINAL is for undefined symbols in a two-level namespace |
230 | * image that are looked up by the dynamic linker with flat namespace semantics. |
231 | * This ordinal was added as a feature in Mac OS X 10.3 by reducing the |
232 | * value of MAX_LIBRARY_ORDINAL by one. So it is legal for existing binaries |
233 | * or binaries built with older tools to have 0xfe (254) dynamic libraries. In |
234 | * this case the ordinal value 0xfe (254) must be treated as a library ordinal |
235 | * for compatibility. |
236 | */ |
237 | #define GET_LIBRARY_ORDINAL(n_desc) (((n_desc) >> 8) & 0xff) |
238 | #define SET_LIBRARY_ORDINAL(n_desc,ordinal) \ |
239 | (n_desc) = (((n_desc) & 0x00ff) | (((ordinal) & 0xff) << 8)) |
240 | #define SELF_LIBRARY_ORDINAL 0x0 |
241 | #define MAX_LIBRARY_ORDINAL 0xfd |
242 | #define DYNAMIC_LOOKUP_ORDINAL 0xfe |
243 | #define EXECUTABLE_ORDINAL 0xff |
244 | |
245 | /* |
246 | * The bit 0x0020 of the n_desc field is used for two non-overlapping purposes |
247 | * and has two different symbolic names, N_NO_DEAD_STRIP and N_DESC_DISCARDED. |
248 | */ |
249 | |
250 | /* |
251 | * The N_NO_DEAD_STRIP bit of the n_desc field only ever appears in a |
252 | * relocatable .o file (MH_OBJECT filetype). And is used to indicate to the |
253 | * static link editor it is never to dead strip the symbol. |
254 | */ |
255 | #define N_NO_DEAD_STRIP 0x0020 /* symbol is not to be dead stripped */ |
256 | |
257 | /* |
258 | * The N_DESC_DISCARDED bit of the n_desc field never appears in linked image. |
259 | * But is used in very rare cases by the dynamic link editor to mark an in |
260 | * memory symbol as discared and longer used for linking. |
261 | */ |
262 | #define N_DESC_DISCARDED 0x0020 /* symbol is discarded */ |
263 | |
264 | /* |
265 | * The N_WEAK_REF bit of the n_desc field indicates to the dynamic linker that |
266 | * the undefined symbol is allowed to be missing and is to have the address of |
267 | * zero when missing. |
268 | */ |
269 | #define N_WEAK_REF 0x0040 /* symbol is weak referenced */ |
270 | |
271 | /* |
272 | * The N_WEAK_DEF bit of the n_desc field indicates to the static and dynamic |
273 | * linkers that the symbol definition is weak, allowing a non-weak symbol to |
274 | * also be used which causes the weak definition to be discared. Currently this |
275 | * is only supported for symbols in coalesed sections. |
276 | */ |
277 | #define N_WEAK_DEF 0x0080 /* coalesed symbol is a weak definition */ |
278 | |
279 | /* |
280 | * The N_REF_TO_WEAK bit of the n_desc field indicates to the dynamic linker |
281 | * that the undefined symbol should be resolved using flat namespace searching. |
282 | */ |
283 | #define N_REF_TO_WEAK 0x0080 /* reference to a weak symbol */ |
284 | |
285 | /* |
286 | * The N_ARM_THUMB_DEF bit of the n_desc field indicates that the symbol is |
287 | * a defintion of a Thumb function. |
288 | */ |
289 | #define N_ARM_THUMB_DEF 0x0008 /* symbol is a Thumb function (ARM) */ |
290 | |
291 | /* |
292 | * The N_SYMBOL_RESOLVER bit of the n_desc field indicates that the |
293 | * that the function is actually a resolver function and should |
294 | * be called to get the address of the real function to use. |
295 | * This bit is only available in .o files (MH_OBJECT filetype) |
296 | */ |
297 | #define N_SYMBOL_RESOLVER 0x0100 |
298 | |
299 | /* |
300 | * The N_ALT_ENTRY bit of the n_desc field indicates that the |
301 | * symbol is pinned to the previous content. |
302 | */ |
303 | #define N_ALT_ENTRY 0x0200 |
304 | |
305 | #ifndef __STRICT_BSD__ |
306 | #ifdef __cplusplus |
307 | extern "C" { |
308 | #endif /* __cplusplus */ |
309 | /* |
310 | * The function nlist(3) from the C library. |
311 | */ |
312 | extern int nlist (const char *filename, struct nlist *list); |
313 | #ifdef __cplusplus |
314 | } |
315 | #endif /* __cplusplus */ |
316 | #endif /* __STRICT_BSD__ */ |
317 | |
318 | #endif /* _MACHO_LIST_H_ */ |
319 | |