Annotation of src/include/link.h, Revision 1.10
1.10 ! deraadt 1: /* $OpenBSD: link.h,v 1.9 2002/02/16 21:27:17 millert Exp $ */
1.2 deraadt 2: /* $NetBSD: link.h,v 1.10 1996/01/09 00:00:11 pk Exp $ */
1.1 deraadt 3:
4: /*
5: * Copyright (c) 1993 Paul Kranenburg
6: * All rights reserved.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. All advertising materials mentioning features or use of this software
17: * must display the following acknowledgement:
18: * This product includes software developed by Paul Kranenburg.
19: * 4. The name of the author may not be used to endorse or promote products
1.10 ! deraadt 20: * derived from this software without specific prior written permission
1.1 deraadt 21: *
22: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32: */
33:
34: /*
35: * RRS section definitions.
36: *
37: * The layout of some data structures defined in this header file is
38: * such that we can provide compatibility with the SunOS 4.x shared
39: * library scheme.
40: */
41:
42: #ifndef _LINK_H_
43: #define _LINK_H_
1.6 art 44:
45: /* XXXART - ? */
46: #ifndef DT_PROCNUM
47: #define DT_PROCNUM 0
48: #endif
1.1 deraadt 49:
50: /*
1.4 espie 51: * A `Shared Object Descriptor' describes a shared object that is needed
1.1 deraadt 52: * to complete the link edit process of the object containing it.
53: * A list of such objects (chained through `sod_next') is pointed at
54: * by `sdt_sods' in the section_dispatch_table structure.
55: */
56:
57: struct sod { /* Shared Object Descriptor */
58: long sod_name; /* name (relative to load address) */
59: u_int sod_library : 1, /* Searched for by library rules */
60: sod_reserved : 31;
61: short sod_major; /* major version number */
62: short sod_minor; /* minor version number */
63: long sod_next; /* next sod */
64: };
65:
66: /*
67: * `Shared Object Map's are used by the run-time link editor (ld.so) to
68: * keep track of all shared objects loaded into a process' address space.
69: * These structures are only used at run-time and do not occur within
70: * the text or data segment of an executable or shared library.
71: */
72: struct so_map { /* Shared Object Map */
73: caddr_t som_addr; /* Address at which object mapped */
74: char *som_path; /* Path to mmap'ed file */
75: struct so_map *som_next; /* Next map in chain */
76: struct sod *som_sod; /* Sod responsible for this map */
77: caddr_t som_sodbase; /* Base address of this sod */
78: u_int som_write : 1; /* Text is currently writable */
79: struct _dynamic *som_dynamic; /* _dynamic structure */
80: caddr_t som_spd; /* Private data */
81: };
82:
83: /*
84: * Symbol description with size. This is simply an `nlist' with
85: * one field (nz_size) added.
86: * Used to convey size information on items in the data segment
87: * of shared objects. An array of these live in the shared object's
88: * text segment and is addressed by the `sdt_nzlist' field.
89: */
90: struct nzlist {
91: struct nlist nlist;
92: u_long nz_size;
93: #define nz_un nlist.n_un
94: #define nz_strx nlist.n_un.n_strx
95: #define nz_name nlist.n_un.n_name
96: #define nz_type nlist.n_type
97: #define nz_value nlist.n_value
98: #define nz_desc nlist.n_desc
99: #define nz_other nlist.n_other
100: };
101:
102: #define N_AUX(p) ((p)->n_other & 0xf)
103: #define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf)
104: #define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf))
105:
106: #define AUX_OBJECT 1
107: #define AUX_FUNC 2
108: /*#define BIND_LOCAL 0 not used */
109: /*#define BIND_GLOBAL 1 not used */
110: #define BIND_WEAK 2
111:
112:
113: /*
114: * The `section_dispatch_table' structure contains offsets to various data
115: * structures needed to do run-time relocation.
116: */
117: struct section_dispatch_table {
118: struct so_map *sdt_loaded; /* List of loaded objects */
119: long sdt_sods; /* List of shared objects descriptors */
120: long sdt_paths; /* Library search paths */
121: long sdt_got; /* Global offset table */
122: long sdt_plt; /* Procedure linkage table */
123: long sdt_rel; /* Relocation table */
124: long sdt_hash; /* Symbol hash table */
125: long sdt_nzlist; /* Symbol table itself */
126: long sdt_filler2; /* Unused (was: stab_hash) */
127: long sdt_buckets; /* Number of hash buckets */
128: long sdt_strings; /* Symbol strings */
129: long sdt_str_sz; /* Size of symbol strings */
130: long sdt_text_sz; /* Size of text area */
131: long sdt_plt_sz; /* Size of procedure linkage table */
132: };
133:
134: /*
135: * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table.
136: * Used to quickly lookup symbols of the shared object by hashing
137: * on the symbol's name. `rh_symbolnum' is the index of the symbol
138: * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is
139: * the next symbol in the hash bucket (in case of collisions).
140: */
141: struct rrs_hash {
142: int rh_symbolnum; /* Symbol number */
143: int rh_next; /* Next hash entry */
144: };
145:
146: /*
147: * `rt_symbols' is used to keep track of run-time allocated commons
148: * and data items copied from shared objects.
149: */
150: struct rt_symbol {
151: struct nzlist *rt_sp; /* The symbol */
152: struct rt_symbol *rt_next; /* Next in linear list */
153: struct rt_symbol *rt_link; /* Next in bucket */
154: caddr_t rt_srcaddr; /* Address of "master" copy */
155: struct so_map *rt_smp; /* Originating map */
156: };
157:
158: /*
159: * Debugger interface structure.
160: */
161: struct so_debug {
162: int dd_version; /* Version # of interface */
163: int dd_in_debugger; /* Set when run by debugger */
164: int dd_sym_loaded; /* Run-time linking brought more
165: symbols into scope */
166: char *dd_bpt_addr; /* Address of rtld-generated bpt */
167: int dd_bpt_shadow; /* Original contents of bpt */
168: struct rt_symbol *dd_cc; /* Allocated commons/copied data */
169: };
1.7 art 170:
171: /*
172: * Debug rendezvous struct. Pointer to this is set up in the
1.8 art 173: * target code pointed by the DT_DEBUG tag. If it is
1.7 art 174: * defined.
175: */
176: struct r_debug {
177: int r_version; /* Protocol version. */
178: struct link_map *r_map; /* Head of list of loaded objects. */
179:
180: /*
181: * This is the address of a function internal to the run-time linker,
182: * that will always be called when the linker begins to map in a
183: * library or unmap it, and again when the mapping change is complete.
184: * The debugger can set a breakpoint at this address if it wants to
185: * notice shared object mapping changes.
186: */
1.8 art 187: unsigned long r_brk;
1.7 art 188: enum {
189: /*
190: * This state value describes the mapping change taking place
191: * when the `r_brk' address is called.
192: */
193: RT_CONSISTENT, /* Mapping change is complete. */
194: RT_ADD, /* Adding a new object. */
195: RT_DELETE, /* Removing an object mapping. */
196: } r_state;
197:
1.8 art 198: unsigned long r_ldbase; /* Base address the linker is loaded at. */
1.7 art 199: };
1.1 deraadt 200:
201: /*
202: * Entry points into ld.so - user interface to the run-time linker.
203: */
204: struct ld_entry {
1.9 millert 205: void *(*dlopen)(const char *, int);
206: int (*dlclose)(void *);
207: void *(*dlsym)(void *, const char *);
208: int (*dlctl)(void *, int, void *);
209: void (*dlexit)(void);
210: void (*dlrsrvd[3])(void);
1.1 deraadt 211: };
212:
213: /*
214: * This is the structure pointed at by the __DYNAMIC symbol if an
215: * executable requires the attention of the run-time link editor.
216: * __DYNAMIC is given the value zero if no run-time linking needs to
217: * be done (it is always present in shared objects).
218: * The union `d_un' provides for different versions of the dynamic
219: * linking mechanism (switched on by `d_version'). The last version
220: * used by Sun is 3. We leave some room here and go to version number
221: * 8 for NetBSD, the main difference lying in the support for the
222: * `nz_list' type of symbols.
223: */
224:
225: struct _dynamic {
226: int d_version; /* version # of this interface */
227: struct so_debug *d_debug;
228: union {
229: struct section_dispatch_table *d_sdt;
230: } d_un;
231: struct ld_entry *d_entry; /* compat - now in crt_ldso */
232: };
233:
234: #define LD_VERSION_SUN (3)
235: #define LD_VERSION_BSD (8)
236: #define LD_VERSION_NZLIST_P(v) ((v) >= 8)
237:
238: #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got)
239: #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt)
240: #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel)
241: #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist)
242: #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash)
243: #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings)
244: #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods)
245: #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets)
246: #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths)
247:
248: #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got)
249: #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel)
250: #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash)
251: #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist)
252: #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz)
253: #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz)
254: #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz)
255:
256: /*
257: * Interface to ld.so
258: */
259: struct crt_ldso {
260: int crt_ba; /* Base address of ld.so */
261: int crt_dzfd; /* "/dev/zero" file decriptor (SunOS) */
262: int crt_ldfd; /* ld.so file descriptor */
263: struct _dynamic *crt_dp; /* Main's __DYNAMIC */
264: char **crt_ep; /* environment strings */
265: caddr_t crt_bp; /* Breakpoint if run from debugger */
266: char *crt_prog; /* Program name (v3) */
267: char *crt_ldso; /* Link editor name (v4) */
268: struct ld_entry *crt_ldentry; /* dl*() access (v4) */
269: };
270:
271: /*
272: * Version passed from crt0 to ld.so (1st argument to _rtld()).
273: */
274: #define CRT_VERSION_SUN 1
275: #define CRT_VERSION_BSD_2 2
276: #define CRT_VERSION_BSD_3 3
277: #define CRT_VERSION_BSD_4 4
278:
279:
280: /*
281: * Maximum number of recognized shared object version numbers.
282: */
283: #define MAXDEWEY 8
284:
285: /*
286: * Header of the hints file.
287: */
288: struct hints_header {
289: long hh_magic;
290: #define HH_MAGIC 011421044151
291: long hh_version; /* Interface version number */
292: #define LD_HINTS_VERSION_1 1
1.2 deraadt 293: #define LD_HINTS_VERSION_2 2
1.1 deraadt 294: long hh_hashtab; /* Location of hash table */
295: long hh_nbucket; /* Number of buckets in hashtab */
296: long hh_strtab; /* Location of strings */
297: long hh_strtab_sz; /* Size of strings */
298: long hh_ehints; /* End of hints (max offset in file) */
1.2 deraadt 299: long hh_dirlist; /* Colon-separated list of srch dirs */
1.1 deraadt 300: };
301:
302: #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC)
303:
304: /*
305: * Hash table element in hints file.
306: */
307: struct hints_bucket {
308: /* namex and pathx are indices into the string table */
309: int hi_namex; /* Library name */
310: int hi_pathx; /* Full path */
311: int hi_dewey[MAXDEWEY]; /* The versions */
312: int hi_ndewey; /* Number of version numbers */
313: #define hi_major hi_dewey[0]
314: #define hi_minor hi_dewey[1]
315: int hi_next; /* Next in this bucket */
316: };
317:
318: #define _PATH_LD_HINTS "/var/run/ld.so.hints"
319:
320: #endif /* _LINK_H_ */
321:
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