FreeBSD/Linux Kernel Cross Reference
sys/sys/link_aout.h
1 /*
2 * Copyright (c) 1993 Paul Kranenburg
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 * This product includes software developed by Paul Kranenburg.
16 * 4. The name of the author may not be used to endorse or promote products
17 * derived from this software without specific prior written permission
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 *
30 * $FreeBSD: src/sys/sys/link_aout.h,v 1.9.2.3 1999/09/05 11:14:13 peter Exp $
31 */
32
33 /*
34 * RRS section definitions.
35 *
36 * The layout of some data structures defined in this header file is
37 * such that we can provide compatibility with the SunOS 4.x shared
38 * library scheme.
39 */
40
41 #ifndef _LINK_H_
42 #define _LINK_H_
43
44 /*
45 * A `Shared Object Descriptor' describes a shared object that is needed
46 * to complete the link edit process of the object containing it.
47 * A list of such objects (chained through `sod_next') is pointed at
48 * by `sdt_sods' in the section_dispatch_table structure.
49 */
50
51 struct sod { /* Shared Object Descriptor */
52 long sod_name; /* name (relative to load address) */
53 u_int sod_library : 1, /* Searched for by library rules */
54 sod_reserved : 31;
55 short sod_major; /* major version number */
56 short sod_minor; /* minor version number */
57 long sod_next; /* next sod */
58 };
59
60 /*
61 * `Shared Object Map's are used by the run-time link editor (ld.so) to
62 * keep track of all shared objects loaded into a process' address space.
63 * These structures are only used at run-time and do not occur within
64 * the text or data segment of an executable or shared library.
65 */
66 struct so_map { /* Shared Object Map */
67 caddr_t som_addr; /* Address at which object mapped */
68 char *som_path; /* Path to mmap'ed file */
69 struct so_map *som_next; /* Next map in chain */
70 struct sod *som_sod; /* Sod responsible for this map */
71 caddr_t som_sodbase; /* Base address of this sod */
72 u_int som_write : 1; /* Text is currently writable */
73 struct _dynamic *som_dynamic; /* _dynamic structure */
74 caddr_t som_spd; /* Private data */
75 };
76
77 /*
78 * Symbol description with size. This is simply an `nlist' with
79 * one field (nz_size) added.
80 * Used to convey size information on items in the data segment
81 * of shared objects. An array of these live in the shared object's
82 * text segment and is addressed by the `sdt_nzlist' field.
83 */
84 struct nzlist {
85 struct nlist nlist;
86 u_long nz_size;
87 #define nz_un nlist.n_un
88 #define nz_strx nlist.n_un.n_strx
89 #define nz_name nlist.n_un.n_name
90 #define nz_type nlist.n_type
91 #define nz_value nlist.n_value
92 #define nz_desc nlist.n_desc
93 #define nz_other nlist.n_other
94 };
95
96 #define N_AUX(p) ((p)->n_other & 0xf)
97 #define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf)
98 #define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf))
99
100 #define AUX_OBJECT 1
101 #define AUX_FUNC 2
102 /*#define BIND_LOCAL 0 not used */
103 /*#define BIND_GLOBAL 1 not used */
104 #define BIND_WEAK 2
105
106
107 /*
108 * The `section_dispatch_table' structure contains offsets to various data
109 * structures needed to do run-time relocation.
110 */
111 struct section_dispatch_table {
112 struct so_map *sdt_loaded; /* List of loaded objects */
113 long sdt_sods; /* List of shared objects descriptors */
114 long sdt_paths; /* Library search paths */
115 long sdt_got; /* Global offset table */
116 long sdt_plt; /* Procedure linkage table */
117 long sdt_rel; /* Relocation table */
118 long sdt_hash; /* Symbol hash table */
119 long sdt_nzlist; /* Symbol table itself */
120 long sdt_filler2; /* Unused (was: stab_hash) */
121 long sdt_buckets; /* Number of hash buckets */
122 long sdt_strings; /* Symbol strings */
123 long sdt_str_sz; /* Size of symbol strings */
124 long sdt_text_sz; /* Size of text area */
125 long sdt_plt_sz; /* Size of procedure linkage table */
126 };
127
128 /*
129 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table.
130 * Used to quickly lookup symbols of the shared object by hashing
131 * on the symbol's name. `rh_symbolnum' is the index of the symbol
132 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is
133 * the next symbol in the hash bucket (in case of collisions).
134 */
135 struct rrs_hash {
136 int rh_symbolnum; /* Symbol number */
137 int rh_next; /* Next hash entry */
138 };
139
140 /*
141 * `rt_symbols' is used to keep track of run-time allocated commons
142 * and data items copied from shared objects.
143 */
144 struct rt_symbol {
145 struct nzlist *rt_sp; /* The symbol */
146 struct rt_symbol *rt_next; /* Next in linear list */
147 struct rt_symbol *rt_link; /* Next in bucket */
148 caddr_t rt_srcaddr; /* Address of "master" copy */
149 struct so_map *rt_smp; /* Originating map */
150 };
151
152 /*
153 * Debugger interface structure.
154 */
155 struct so_debug {
156 int dd_version; /* Version # of interface */
157 int dd_in_debugger; /* Set when run by debugger */
158 int dd_sym_loaded; /* Run-time linking brought more
159 symbols into scope */
160 char *dd_bpt_addr; /* Address of rtld-generated bpt */
161 int dd_bpt_shadow; /* Original contents of bpt */
162 struct rt_symbol *dd_cc; /* Allocated commons/copied data */
163 };
164
165 /*
166 * Version returned to crt0 from ld.so
167 */
168 #define LDSO_VERSION_NONE 0 /* FreeBSD2.0, 2.0.5 */
169 #define LDSO_VERSION_HAS_DLEXIT 1 /* includes dlexit in ld_entry */
170 #define LDSO_VERSION_HAS_DLSYM3 2 /* includes 3-argument dlsym */
171
172 /*
173 * Entry points into ld.so - user interface to the run-time linker.
174 * Entries are valid for the given version numbers returned by ld.so
175 * to crt0.
176 */
177 struct ld_entry {
178 void *(*dlopen) __P((const char *, int)); /* NONE */
179 int (*dlclose) __P((void *)); /* NONE */
180 void *(*dlsym) __P((void *, const char *)); /* NONE */
181 const char *(*dlerror) __P((void)); /* NONE */
182 void (*dlexit) __P((void)); /* HAS_DLEXIT */
183 void *(*dlsym3) __P((void *, const char *, void *)); /* HAS_DLSYM3 */
184 };
185
186 /*
187 * dl*() prototypes.
188 */
189 extern void *dlopen __P((const char *, int));
190 extern int dlclose __P((void *));
191 extern void *dlsym __P((void *, const char *));
192 extern const char *dlerror __P((void));
193
194
195 /*
196 * This is the structure pointed at by the __DYNAMIC symbol if an
197 * executable requires the attention of the run-time link editor.
198 * __DYNAMIC is given the value zero if no run-time linking needs to
199 * be done (it is always present in shared objects).
200 * The union `d_un' provides for different versions of the dynamic
201 * linking mechanism (switched on by `d_version'). The last version
202 * used by Sun is 3. We leave some room here and go to version number
203 * 8 for NetBSD, the main difference lying in the support for the
204 * `nz_list' type of symbols.
205 */
206
207 struct _dynamic {
208 int d_version; /* version # of this interface */
209 struct so_debug *d_debug;
210 union {
211 struct section_dispatch_table *d_sdt;
212 } d_un;
213 struct ld_entry *d_entry; /* XXX */
214 };
215
216 #define LD_VERSION_SUN (3)
217 #define LD_VERSION_BSD (8)
218 #define LD_VERSION_NZLIST_P(v) ((v) >= 8)
219
220 #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got)
221 #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt)
222 #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel)
223 #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist)
224 #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash)
225 #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings)
226 #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods)
227 #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets)
228 #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths)
229
230 #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got)
231 #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel)
232 #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash)
233 #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist)
234 #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz)
235 #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz)
236 #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz)
237
238 /*
239 * Interface to ld.so
240 */
241 struct crt_ldso {
242 int crt_ba; /* Base address of ld.so */
243 int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */
244 int crt_ldfd; /* ld.so file descriptor */
245 struct _dynamic *crt_dp; /* Main's __DYNAMIC */
246 char **crt_ep; /* environment strings */
247 caddr_t crt_bp; /* Breakpoint if run from debugger */
248 char *crt_prog; /* Program name (v3) */
249 char *crt_ldso; /* Link editor name (v4) */
250 struct ld_entry *crt_ldentry; /* dl*() access (v4) */
251 };
252
253 /*
254 * Version passed from crt0 to ld.so (1st argument to _rtld()).
255 */
256 #define CRT_VERSION_SUN 1
257 #define CRT_VERSION_BSD_2 2
258 #define CRT_VERSION_BSD_3 3
259 #define CRT_VERSION_BSD_4 4
260
261 /*
262 * Maximum number of recognized shared object version numbers.
263 */
264 #define MAXDEWEY 8
265
266 /*
267 * Header of the hints file.
268 */
269 struct hints_header {
270 long hh_magic;
271 #define HH_MAGIC 011421044151
272 long hh_version; /* Interface version number */
273 #define LD_HINTS_VERSION_1 1
274 #define LD_HINTS_VERSION_2 2
275 long hh_hashtab; /* Location of hash table */
276 long hh_nbucket; /* Number of buckets in hashtab */
277 long hh_strtab; /* Location of strings */
278 long hh_strtab_sz; /* Size of strings */
279 long hh_ehints; /* End of hints (max offset in file) */
280 long hh_dirlist; /* Colon-separated list of srch dirs */
281 };
282
283 #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC)
284
285 /*
286 * Hash table element in hints file.
287 */
288 struct hints_bucket {
289 /* namex and pathx are indices into the string table */
290 int hi_namex; /* Library name */
291 int hi_pathx; /* Full path */
292 int hi_dewey[MAXDEWEY]; /* The versions */
293 int hi_ndewey; /* Number of version numbers */
294 #define hi_major hi_dewey[0]
295 #define hi_minor hi_dewey[1]
296 int hi_next; /* Next in this bucket */
297 };
298
299 #define _PATH_LD_HINTS "/var/run/ld.so.hints"
300
301 #endif /* _LINK_H_ */
302
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