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#ifndef _MACHO_NLIST_H_
#define _MACHO_NLIST_H_
/*
* Copyright (c) 1980 Regents of the University of California.
* All rights reserved. The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*
* @(#)nlist.h 5.1 (Berkeley) 5/30/85
*/
/*
* Format of a symbol table entry of a Mach-O file. Modified from the 4.3BSD
* 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 an arbitrary number of
* sections not just the three sections (text, data and bss) in a 4.3BSD file.
*/
struct nlist {
union {
char *n_name; /* for use when in-core */
long n_strx; /* index into the string table */
} n_un;
unsigned char n_type; /* type flag, see below */
unsigned char n_sect; /* section number or NO_SECT */
short n_desc; /* see <mach-o/stab.h> */
unsigned long 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 three 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_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.
*/
/*
* 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 0xff
/* 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
#ifndef __STRICT_BSD__
/*
* The function nlist(3) from the C library.
*/
extern int nlist (const char *filename, struct nlist *list);
#endif __STRICT_BSD__
#endif _MACHO_LIST_H_
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