/* * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved. * * @APPLE_LICENSE_HEADER_START@ * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The Original Code and all software distributed under the License are * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ #ifndef _MACHO_NLIST_H_ #define _MACHO_NLIST_H_ /* $NetBSD: nlist.h,v 1.5 1994/10/26 00:56:11 cgd Exp $ */ /*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * (c) UNIX System Laboratories, Inc. * All or some portions of this file are derived from material licensed * to the University of California by American Telephone and Telegraph * Co. or Unix System Laboratories, Inc. and are reproduced herein with * the permission of UNIX System Laboratories, Inc. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * @(#)nlist.h 8.2 (Berkeley) 1/21/94 */ #include <stdint.h> /* * Format of a symbol table entry of a Mach-O file for 32-bit architectures. * Modified from the BSD format. The modifications from the original format * were changing n_other (an unused field) to n_sect and the addition of the * N_SECT type. These modifications are required to support symbols in a larger * number of sections not just the three sections (text, data and bss) in a BSD * file. */ struct nlist { union { #ifndef __LP64__ char *n_name; /* for use when in-core */ #endif uint32_t n_strx; /* index into the string table */ } n_un; uint8_t n_type; /* type flag, see below */ uint8_t n_sect; /* section number or NO_SECT */ int16_t n_desc; /* see <mach-o/stab.h> */ uint32_t n_value; /* value of this symbol (or stab offset) */ }; /* * This is the symbol table entry structure for 64-bit architectures. */ struct nlist_64 { union { uint32_t n_strx; /* index into the string table */ } n_un; uint8_t n_type; /* type flag, see below */ uint8_t n_sect; /* section number or NO_SECT */ uint16_t n_desc; /* see <mach-o/stab.h> */ uint64_t n_value; /* value of this symbol (or stab offset) */ }; /* * Symbols with a index into the string table of zero (n_un.n_strx == 0) are * defined to have a null, "", name. Therefore all string indexes to non null * names must not have a zero string index. This is bit historical information * that has never been well documented. */ /* * The n_type field really contains four fields: * unsigned char N_STAB:3, * N_PEXT:1, * N_TYPE:3, * N_EXT:1; * which are used via the following masks. */ #define N_STAB 0xe0 /* if any of these bits set, a symbolic debugging entry */ #define N_PEXT 0x10 /* private external symbol bit */ #define N_TYPE 0x0e /* mask for the type bits */ #define N_EXT 0x01 /* external symbol bit, set for external symbols */ /* * Only symbolic debugging entries have some of the N_STAB bits set and if any * of these bits are set then it is a symbolic debugging entry (a stab). In * which case then the values of the n_type field (the entire field) are given * in <mach-o/stab.h> */ /* * Values for N_TYPE bits of the n_type field. */ #define N_UNDF 0x0 /* undefined, n_sect == NO_SECT */ #define N_ABS 0x2 /* absolute, n_sect == NO_SECT */ #define N_SECT 0xe /* defined in section number n_sect */ #define N_PBUD 0xc /* prebound undefined (defined in a dylib) */ #define N_INDR 0xa /* indirect */ /* * If the type is N_INDR then the symbol is defined to be the same as another * symbol. In this case the n_value field is an index into the string table * of the other symbol's name. When the other symbol is defined then they both * take on the defined type and value. */ /* * If the type is N_SECT then the n_sect field contains an ordinal of the * section the symbol is defined in. The sections are numbered from 1 and * refer to sections in order they appear in the load commands for the file * they are in. This means the same ordinal may very well refer to different * sections in different files. * * The n_value field for all symbol table entries (including N_STAB's) gets * updated by the link editor based on the value of it's n_sect field and where * the section n_sect references gets relocated. If the value of the n_sect * field is NO_SECT then it's n_value field is not changed by the link editor. */ #define NO_SECT 0 /* symbol is not in any section */ #define MAX_SECT 255 /* 1 thru 255 inclusive */ /* * Common symbols are represented by undefined (N_UNDF) external (N_EXT) types * who's values (n_value) are non-zero. In which case the value of the n_value * field is the size (in bytes) of the common symbol. The n_sect field is set * to NO_SECT. The alignment of a common symbol may be set as a power of 2 * between 2^1 and 2^15 as part of the n_desc field using the macros below. If * the alignment is not set (a value of zero) then natural alignment based on * the size is used. */ #define GET_COMM_ALIGN(n_desc) (((n_desc) >> 8) & 0x0f) #define SET_COMM_ALIGN(n_desc,align) \ (n_desc) = (((n_desc) & 0xf0ff) | (((align) & 0x0f) << 8)) /* * To support the lazy binding of undefined symbols in the dynamic link-editor, * the undefined symbols in the symbol table (the nlist structures) are marked * with the indication if the undefined reference is a lazy reference or * non-lazy reference. If both a non-lazy reference and a lazy reference is * made to the same symbol the non-lazy reference takes precedence. A reference * is lazy only when all references to that symbol are made through a symbol * pointer in a lazy symbol pointer section. * * The implementation of marking nlist structures in the symbol table for * undefined symbols will be to use some of the bits of the n_desc field as a * reference type. The mask REFERENCE_TYPE will be applied to the n_desc field * of an nlist structure for an undefined symbol to determine the type of * undefined reference (lazy or non-lazy). * * The constants for the REFERENCE FLAGS are propagated to the reference table * in a shared library file. In that case the constant for a defined symbol, * REFERENCE_FLAG_DEFINED, is also used. */ /* Reference type bits of the n_desc field of undefined symbols */ #define REFERENCE_TYPE 0x7 /* types of references */ #define REFERENCE_FLAG_UNDEFINED_NON_LAZY 0 #define REFERENCE_FLAG_UNDEFINED_LAZY 1 #define REFERENCE_FLAG_DEFINED 2 #define REFERENCE_FLAG_PRIVATE_DEFINED 3 #define REFERENCE_FLAG_PRIVATE_UNDEFINED_NON_LAZY 4 #define REFERENCE_FLAG_PRIVATE_UNDEFINED_LAZY 5 /* * To simplify stripping of objects that use are used with the dynamic link * editor, the static link editor marks the symbols defined an object that are * referenced by a dynamicly bound object (dynamic shared libraries, bundles). * With this marking strip knows not to strip these symbols. */ #define REFERENCED_DYNAMICALLY 0x0010 /* * For images created by the static link editor with the -twolevel_namespace * option in effect the flags field of the mach header is marked with * MH_TWOLEVEL. And the binding of the undefined references of the image are * determined by the static link editor. Which library an undefined symbol is * bound to is recorded by the static linker in the high 8 bits of the n_desc * field using the SET_LIBRARY_ORDINAL macro below. The ordinal recorded * references the libraries listed in the Mach-O's LC_LOAD_DYLIB, * LC_LOAD_WEAK_DYLIB, LC_REEXPORT_DYLIB, LC_LOAD_UPWARD_DYLIB, and * LC_LAZY_LOAD_DYLIB, etc. load commands in the order they appear in the * headers. The library ordinals start from 1. * For a dynamic library that is built as a two-level namespace image the * undefined references from module defined in another use the same nlist struct * an in that case SELF_LIBRARY_ORDINAL is used as the library ordinal. For * defined symbols in all images they also must have the library ordinal set to * SELF_LIBRARY_ORDINAL. The EXECUTABLE_ORDINAL refers to the executable * image for references from plugins that refer to the executable that loads * them. * * The DYNAMIC_LOOKUP_ORDINAL is for undefined symbols in a two-level namespace * image that are looked up by the dynamic linker with flat namespace semantics. * This ordinal was added as a feature in Mac OS X 10.3 by reducing the * value of MAX_LIBRARY_ORDINAL by one. So it is legal for existing binaries * or binaries built with older tools to have 0xfe (254) dynamic libraries. In * this case the ordinal value 0xfe (254) must be treated as a library ordinal * for compatibility. */ #define GET_LIBRARY_ORDINAL(n_desc) (((n_desc) >> 8) & 0xff) #define SET_LIBRARY_ORDINAL(n_desc,ordinal) \ (n_desc) = (((n_desc) & 0x00ff) | (((ordinal) & 0xff) << 8)) #define SELF_LIBRARY_ORDINAL 0x0 #define MAX_LIBRARY_ORDINAL 0xfd #define DYNAMIC_LOOKUP_ORDINAL 0xfe #define EXECUTABLE_ORDINAL 0xff /* * The bit 0x0020 of the n_desc field is used for two non-overlapping purposes * and has two different symbolic names, N_NO_DEAD_STRIP and N_DESC_DISCARDED. */ /* * The N_NO_DEAD_STRIP bit of the n_desc field only ever appears in a * relocatable .o file (MH_OBJECT filetype). And is used to indicate to the * static link editor it is never to dead strip the symbol. */ #define N_NO_DEAD_STRIP 0x0020 /* symbol is not to be dead stripped */ /* * The N_DESC_DISCARDED bit of the n_desc field never appears in linked image. * But is used in very rare cases by the dynamic link editor to mark an in * memory symbol as discared and longer used for linking. */ #define N_DESC_DISCARDED 0x0020 /* symbol is discarded */ /* * The N_WEAK_REF bit of the n_desc field indicates to the dynamic linker that * the undefined symbol is allowed to be missing and is to have the address of * zero when missing. */ #define N_WEAK_REF 0x0040 /* symbol is weak referenced */ /* * The N_WEAK_DEF bit of the n_desc field indicates to the static and dynamic * linkers that the symbol definition is weak, allowing a non-weak symbol to * also be used which causes the weak definition to be discared. Currently this * is only supported for symbols in coalesed sections. */ #define N_WEAK_DEF 0x0080 /* coalesed symbol is a weak definition */ /* * The N_REF_TO_WEAK bit of the n_desc field indicates to the dynamic linker * that the undefined symbol should be resolved using flat namespace searching. */ #define N_REF_TO_WEAK 0x0080 /* reference to a weak symbol */ /* * The N_ARM_THUMB_DEF bit of the n_desc field indicates that the symbol is * a defintion of a Thumb function. */ #define N_ARM_THUMB_DEF 0x0008 /* symbol is a Thumb function (ARM) */ /* * The N_SYMBOL_RESOLVER bit of the n_desc field indicates that the * that the function is actually a resolver function and should * be called to get the address of the real function to use. * This bit is only available in .o files (MH_OBJECT filetype) */ #define N_SYMBOL_RESOLVER 0x0100 /* * The N_ALT_ENTRY bit of the n_desc field indicates that the * symbol is pinned to the previous content. */ #define N_ALT_ENTRY 0x0200 #ifndef __STRICT_BSD__ #ifdef __cplusplus extern "C" { #endif /* __cplusplus */ /* * The function nlist(3) from the C library. */ extern int nlist (const char *filename, struct nlist *list); #ifdef __cplusplus } #endif /* __cplusplus */ #endif /* __STRICT_BSD__ */ #endif /* _MACHO_LIST_H_ */