1/* $NetBSD: link_aout.h,v 1.23 2016/01/23 01:26:14 dholland Exp $ */
2
3/*-
4 * Copyright (c) 1998 The NetBSD Foundation, Inc.
5 * All rights reserved.
6 *
7 * This code is derived from software contributed to The NetBSD Foundation
8 * by Paul Kranenburg.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 */
31
32/*
33 * RRS section definitions.
34 *
35 * The layout of some data structures defined in this header file is
36 * such that we can provide compatibility with the SunOS 4.x shared
37 * library scheme.
38 */
39
40#ifndef _LINK_AOUT_H_
41#define _LINK_AOUT_H_
42
43#include <dlfcn.h> /* for Dl_info */
44#include <a.out.h> /* for struct nlist */
45
46/*
47 * A `Shared Object Descriptor' describes a shared object that is needed
48 * to complete the link edit process of the object containing it.
49 * A list of such objects (chained through `sod_next') is pointed at
50 * by `sdt_sods' in the section_dispatch_table structure.
51 */
52
53struct sod { /* Shared Object Descriptor */
54 long sod_name; /* name (relative to load address) */
55 unsigned int sod_library : 1, /* Searched for by library rules */
56 sod_reserved : 31;
57 short sod_major; /* major version number */
58 short sod_minor; /* minor version number */
59 long sod_next; /* next sod */
60};
61
62/*
63 * `Shared Object Map's are used by the run-time link editor (ld.so) to
64 * keep track of all shared objects loaded into a process' address space.
65 * These structures are only used at run-time and do not occur within
66 * the text or data segment of an executable or shared library.
67 */
68struct so_map { /* Shared Object Map */
69 caddr_t som_addr; /* Address at which object mapped */
70 char *som_path; /* Path to mmap'ed file */
71 struct so_map *som_next; /* Next map in chain */
72 struct sod *som_sod; /* Sod responsible for this map */
73 caddr_t som_sodbase; /* Base address of this sod */
74 unsigned int som_write : 1; /* Text is currently writable */
75 struct _dynamic *som_dynamic; /* _dynamic structure */
76 caddr_t som_spd; /* Private data */
77};
78
79/*
80 * Symbol description with size. This is simply an `nlist' with
81 * one field (nz_size) added.
82 * Used to convey size information on items in the data segment
83 * of shared objects. An array of these live in the shared object's
84 * text segment and is addressed by the `sdt_nzlist' field.
85 */
86struct nzlist {
87 struct nlist nlist;
88 unsigned long nz_size;
89#define nz_un nlist.n_un
90#define nz_strx nlist.n_un.n_strx
91#define nz_name nlist.n_un.n_name
92#define nz_type nlist.n_type
93#define nz_value nlist.n_value
94#define nz_desc nlist.n_desc
95#define nz_other nlist.n_other
96};
97
98#define N_AUX(p) ((p)->n_other & 0xf)
99#define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf)
100#define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf))
101
102#define AUX_OBJECT 1
103#define AUX_FUNC 2
104#define AUX_LABEL 3
105/*#define BIND_LOCAL 0 not used */
106/*#define BIND_GLOBAL 1 not used */
107#define BIND_WEAK 2
108
109
110/*
111 * The `section_dispatch_table' structure contains offsets to various data
112 * structures needed to do run-time relocation.
113 */
114struct section_dispatch_table {
115 struct so_map *sdt_loaded; /* List of loaded objects */
116 long sdt_sods; /* List of shared objects descriptors */
117 long sdt_paths; /* Library search paths */
118 long sdt_got; /* Global offset table */
119 long sdt_plt; /* Procedure linkage table */
120 long sdt_rel; /* Relocation table */
121 long sdt_hash; /* Symbol hash table */
122 long sdt_nzlist; /* Symbol table itself */
123 long sdt_filler2; /* Unused (was: stab_hash) */
124 long sdt_buckets; /* Number of hash buckets */
125 long sdt_strings; /* Symbol strings */
126 long sdt_str_sz; /* Size of symbol strings */
127 long sdt_text_sz; /* Size of text area */
128 long sdt_plt_sz; /* Size of procedure linkage table */
129};
130
131/*
132 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table.
133 * Used to quickly lookup symbols of the shared object by hashing
134 * on the symbol's name. `rh_symbolnum' is the index of the symbol
135 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is
136 * the next symbol in the hash bucket (in case of collisions).
137 */
138struct rrs_hash {
139 int rh_symbolnum; /* Symbol number */
140 int rh_next; /* Next hash entry */
141};
142
143/*
144 * `rt_symbols' is used to keep track of run-time allocated commons
145 * and data items copied from shared objects.
146 */
147struct rt_symbol {
148 struct nzlist *rt_sp; /* The symbol */
149 struct rt_symbol *rt_next; /* Next in linear list */
150 struct rt_symbol *rt_link; /* Next in bucket */
151 caddr_t rt_srcaddr; /* Address of "master" copy */
152 struct so_map *rt_smp; /* Originating map */
153};
154
155/*
156 * Debugger interface structure.
157 */
158struct so_debug {
159 int dd_version; /* Version # of interface */
160 int dd_in_debugger; /* Set when run by debugger */
161 int dd_sym_loaded; /* Run-time linking brought more
162 symbols into scope */
163 char *dd_bpt_addr; /* Address of rtld-generated bpt */
164 int dd_bpt_shadow; /* Original contents of bpt */
165 struct rt_symbol *dd_cc; /* Allocated commons/copied data */
166};
167
168/*
169 * Entry points into ld.so - user interface to the run-time linker.
170 */
171struct ld_entry {
172 void *(*dlopen)(const char *, int);
173 int (*dlclose)(void *);
174 void *(*dlsym)(void *, const char *);
175 int (*dlctl)(void *, int, void *);
176 void (*dlexit)(void);
177 int (*dladdr)(const void *, Dl_info *);
178 void (*dlrsrvd[2])(void);
179};
180
181/*
182 * This is the structure pointed at by the __DYNAMIC symbol if an
183 * executable requires the attention of the run-time link editor.
184 * __DYNAMIC is given the value zero if no run-time linking needs to
185 * be done (it is always present in shared objects).
186 * The union `d_un' provides for different versions of the dynamic
187 * linking mechanism (switched on by `d_version'). The last version
188 * used by Sun is 3. We leave some room here and go to version number
189 * 8 for NetBSD, the main difference lying in the support for the
190 * `nz_list' type of symbols.
191 */
192
193struct _dynamic {
194 int d_version; /* version # of this interface */
195 struct so_debug *d_debug;
196 union {
197 struct section_dispatch_table *d_sdt;
198 } d_un;
199 struct ld_entry *d_entry; /* compat - now in crt_ldso */
200};
201
202#define LD_VERSION_SUN (3)
203#define LD_VERSION_BSD (8)
204#define LD_VERSION_NZLIST_P(v) ((v) >= 8)
205
206#define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got)
207#define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt)
208#define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel)
209#define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist)
210#define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash)
211#define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings)
212#define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods)
213#define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets)
214#define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths)
215
216#define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got)
217#define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel)
218#define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash)
219#define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist)
220#define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz)
221#define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz)
222#define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz)
223
224/*
225 * Interface to ld.so
226 */
227struct crt_ldso {
228 int crt_ba; /* Base address of ld.so */
229 int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */
230 int crt_ldfd; /* ld.so file descriptor */
231 struct _dynamic *crt_dp; /* Main's __DYNAMIC */
232 char **crt_ep; /* environment strings */
233 caddr_t crt_bp; /* Breakpoint if run from debugger */
234 char *crt_prog; /* Program name (v3) */
235 char *crt_ldso; /* Link editor name (v4) */
236 struct ld_entry *crt_ldentry; /* dl*() access (v4) */
237};
238
239/*
240 * Version passed from crt0 to ld.so (1st argument to _rtld()).
241 */
242#define CRT_VERSION_SUN 1
243#define CRT_VERSION_BSD_2 2
244#define CRT_VERSION_BSD_3 3
245#define CRT_VERSION_BSD_4 4
246
247
248/*
249 * Maximum number of recognized shared object version numbers.
250 */
251#define MAXDEWEY 8
252
253/*
254 * Header of the hints file.
255 */
256struct hints_header {
257 long hh_magic;
258#define HH_MAGIC 011421044151
259 long hh_version; /* Interface version number */
260#define LD_HINTS_VERSION_1 1
261#define LD_HINTS_VERSION_2 2
262 long hh_hashtab; /* Location of hash table */
263 long hh_nbucket; /* Number of buckets in hashtab */
264 long hh_strtab; /* Location of strings */
265 long hh_strtab_sz; /* Size of strings */
266 long hh_ehints; /* End of hints (max offset in file) */
267 long hh_dirlist; /* Colon-separated list of srch dirs */
268};
269
270#define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC)
271
272/*
273 * Hash table element in hints file.
274 */
275struct hints_bucket {
276 /* namex and pathx are indices into the string table */
277 int hi_namex; /* Library name */
278 int hi_pathx; /* Full path */
279 int hi_dewey[MAXDEWEY]; /* The versions */
280 int hi_ndewey; /* Number of version numbers */
281#define hi_major hi_dewey[0]
282#define hi_minor hi_dewey[1]
283 int hi_next; /* Next in this bucket */
284};
285
286#define _PATH_LD_HINTS "/var/run/ld.so.hints"
287
288#endif /* _LINK_AOUT_H_ */