Annotation of src/include/link.h, Revision 1.1.1.1
1.1 deraadt 1: /* $NetBSD: link.h,v 1.9 1995/09/23 22:26:15 pk Exp $ */
2:
3: /*
4: * Copyright (c) 1993 Paul Kranenburg
5: * All rights reserved.
6: *
7: * Redistribution and use in source and binary forms, with or without
8: * modification, are permitted provided that the following conditions
9: * are met:
10: * 1. Redistributions of source code must retain the above copyright
11: * notice, this list of conditions and the following disclaimer.
12: * 2. Redistributions in binary form must reproduce the above copyright
13: * notice, this list of conditions and the following disclaimer in the
14: * documentation and/or other materials provided with the distribution.
15: * 3. All advertising materials mentioning features or use of this software
16: * must display the following acknowledgement:
17: * This product includes software developed by Paul Kranenburg.
18: * 4. The name of the author may not be used to endorse or promote products
19: * derived from this software withough specific prior written permission
20: *
21: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22: * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23: * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24: * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25: * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26: * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27: * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28: * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29: * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30: * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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' descibes 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: * Entry points into ld.so - user interface to the run-time linker.
167: */
168: struct ld_entry {
169: void *(*dlopen) __P((char *, int));
170: int (*dlclose) __P((void *));
171: void *(*dlsym) __P((void *, char *));
172: int (*dlctl) __P((void *, int, void *));
173: void (*dlexit) __P((void));
174: void (*dlrsrvd[3]) __P((void));
175: };
176:
177: /*
178: * This is the structure pointed at by the __DYNAMIC symbol if an
179: * executable requires the attention of the run-time link editor.
180: * __DYNAMIC is given the value zero if no run-time linking needs to
181: * be done (it is always present in shared objects).
182: * The union `d_un' provides for different versions of the dynamic
183: * linking mechanism (switched on by `d_version'). The last version
184: * used by Sun is 3. We leave some room here and go to version number
185: * 8 for NetBSD, the main difference lying in the support for the
186: * `nz_list' type of symbols.
187: */
188:
189: struct _dynamic {
190: int d_version; /* version # of this interface */
191: struct so_debug *d_debug;
192: union {
193: struct section_dispatch_table *d_sdt;
194: } d_un;
195: struct ld_entry *d_entry; /* compat - now in crt_ldso */
196: };
197:
198: #define LD_VERSION_SUN (3)
199: #define LD_VERSION_BSD (8)
200: #define LD_VERSION_NZLIST_P(v) ((v) >= 8)
201:
202: #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got)
203: #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt)
204: #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel)
205: #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist)
206: #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash)
207: #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings)
208: #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods)
209: #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets)
210: #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths)
211:
212: #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got)
213: #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel)
214: #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash)
215: #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist)
216: #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz)
217: #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz)
218: #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz)
219:
220: /*
221: * Interface to ld.so
222: */
223: struct crt_ldso {
224: int crt_ba; /* Base address of ld.so */
225: int crt_dzfd; /* "/dev/zero" file decriptor (SunOS) */
226: int crt_ldfd; /* ld.so file descriptor */
227: struct _dynamic *crt_dp; /* Main's __DYNAMIC */
228: char **crt_ep; /* environment strings */
229: caddr_t crt_bp; /* Breakpoint if run from debugger */
230: char *crt_prog; /* Program name (v3) */
231: char *crt_ldso; /* Link editor name (v4) */
232: struct ld_entry *crt_ldentry; /* dl*() access (v4) */
233: };
234:
235: /*
236: * Version passed from crt0 to ld.so (1st argument to _rtld()).
237: */
238: #define CRT_VERSION_SUN 1
239: #define CRT_VERSION_BSD_2 2
240: #define CRT_VERSION_BSD_3 3
241: #define CRT_VERSION_BSD_4 4
242:
243:
244: /*
245: * Maximum number of recognized shared object version numbers.
246: */
247: #define MAXDEWEY 8
248:
249: /*
250: * Header of the hints file.
251: */
252: struct hints_header {
253: long hh_magic;
254: #define HH_MAGIC 011421044151
255: long hh_version; /* Interface version number */
256: #define LD_HINTS_VERSION_1 1
257: long hh_hashtab; /* Location of hash table */
258: long hh_nbucket; /* Number of buckets in hashtab */
259: long hh_strtab; /* Location of strings */
260: long hh_strtab_sz; /* Size of strings */
261: long hh_ehints; /* End of hints (max offset in file) */
262: };
263:
264: #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC)
265:
266: /*
267: * Hash table element in hints file.
268: */
269: struct hints_bucket {
270: /* namex and pathx are indices into the string table */
271: int hi_namex; /* Library name */
272: int hi_pathx; /* Full path */
273: int hi_dewey[MAXDEWEY]; /* The versions */
274: int hi_ndewey; /* Number of version numbers */
275: #define hi_major hi_dewey[0]
276: #define hi_minor hi_dewey[1]
277: int hi_next; /* Next in this bucket */
278: };
279:
280: #define _PATH_LD_HINTS "/var/run/ld.so.hints"
281:
282: #endif /* _LINK_H_ */
283:
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