Annotation of src/include/link_aout.h, Revision 1.2
1.2 ! espie 1: /* $OpenBSD: link_aout.h,v 1.1 2002/06/07 03:00:01 art Exp $ */
1.1 art 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 without 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: /*
42: * Symbol description with size. This is simply an `nlist' with
43: * one field (nz_size) added.
44: * Used to convey size information on items in the data segment
45: * of shared objects. An array of these live in the shared object's
46: * text segment and is addressed by the `sdt_nzlist' field.
47: */
48: struct nzlist {
49: struct nlist nlist;
1.2 ! espie 50: unsigned long nz_size;
1.1 art 51: #define nz_un nlist.n_un
52: #define nz_strx nlist.n_un.n_strx
53: #define nz_name nlist.n_un.n_name
54: #define nz_type nlist.n_type
55: #define nz_value nlist.n_value
56: #define nz_desc nlist.n_desc
57: #define nz_other nlist.n_other
58: };
59:
60: #define N_AUX(p) ((p)->n_other & 0xf)
61: #define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf)
62: #define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf))
63:
64: #define AUX_OBJECT 1
65: #define AUX_FUNC 2
66: /*#define BIND_LOCAL 0 not used */
67: /*#define BIND_GLOBAL 1 not used */
68: #define BIND_WEAK 2
69:
70: /*
71: * The `section_dispatch_table' structure contains offsets to various data
72: * structures needed to do run-time relocation.
73: */
74: struct section_dispatch_table {
75: struct so_map *sdt_loaded; /* List of loaded objects */
76: long sdt_sods; /* List of shared objects descriptors */
77: long sdt_paths; /* Library search paths */
78: long sdt_got; /* Global offset table */
79: long sdt_plt; /* Procedure linkage table */
80: long sdt_rel; /* Relocation table */
81: long sdt_hash; /* Symbol hash table */
82: long sdt_nzlist; /* Symbol table itself */
83: long sdt_filler2; /* Unused (was: stab_hash) */
84: long sdt_buckets; /* Number of hash buckets */
85: long sdt_strings; /* Symbol strings */
86: long sdt_str_sz; /* Size of symbol strings */
87: long sdt_text_sz; /* Size of text area */
88: long sdt_plt_sz; /* Size of procedure linkage table */
89: };
90:
91: /*
92: * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table.
93: * Used to quickly lookup symbols of the shared object by hashing
94: * on the symbol's name. `rh_symbolnum' is the index of the symbol
95: * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is
96: * the next symbol in the hash bucket (in case of collisions).
97: */
98: struct rrs_hash {
99: int rh_symbolnum; /* Symbol number */
100: int rh_next; /* Next hash entry */
101: };
102:
103: /*
104: * `rt_symbols' is used to keep track of run-time allocated commons
105: * and data items copied from shared objects.
106: */
107: struct rt_symbol {
108: struct nzlist *rt_sp; /* The symbol */
109: struct rt_symbol *rt_next; /* Next in linear list */
110: struct rt_symbol *rt_link; /* Next in bucket */
111: caddr_t rt_srcaddr; /* Address of "master" copy */
112: struct so_map *rt_smp; /* Originating map */
113: };
114:
115: /*
116: * Debugger interface structure.
117: */
118: struct so_debug {
119: int dd_version; /* Version # of interface */
120: int dd_in_debugger; /* Set when run by debugger */
121: int dd_sym_loaded; /* Run-time linking brought more
122: symbols into scope */
123: char *dd_bpt_addr; /* Address of rtld-generated bpt */
124: int dd_bpt_shadow; /* Original contents of bpt */
125: struct rt_symbol *dd_cc; /* Allocated commons/copied data */
126: };
127:
128: /*
129: * Entry points into ld.so - user interface to the run-time linker.
130: */
131: struct ld_entry {
132: void *(*dlopen)(const char *, int);
133: int (*dlclose)(void *);
134: void *(*dlsym)(void *, const char *);
135: int (*dlctl)(void *, int, void *);
136: void (*dlexit)(void);
137: void (*dlrsrvd[3])(void);
138: };
139:
140: /*
141: * This is the structure pointed at by the __DYNAMIC symbol if an
142: * executable requires the attention of the run-time link editor.
143: * __DYNAMIC is given the value zero if no run-time linking needs to
144: * be done (it is always present in shared objects).
145: * The union `d_un' provides for different versions of the dynamic
146: * linking mechanism (switched on by `d_version'). The last version
147: * used by Sun is 3. We leave some room here and go to version number
148: * 8 for NetBSD, the main difference lying in the support for the
149: * `nz_list' type of symbols.
150: */
151:
152: struct _dynamic {
153: int d_version; /* version # of this interface */
154: struct so_debug *d_debug;
155: union {
156: struct section_dispatch_table *d_sdt;
157: } d_un;
158: struct ld_entry *d_entry; /* compat - now in crt_ldso */
159: };
160:
161: #define LD_VERSION_SUN (3)
162: #define LD_VERSION_BSD (8)
163: #define LD_VERSION_NZLIST_P(v) ((v) >= 8)
164:
165: #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got)
166: #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt)
167: #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel)
168: #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist)
169: #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash)
170: #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings)
171: #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods)
172: #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets)
173: #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths)
174:
175: #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got)
176: #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel)
177: #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash)
178: #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist)
179: #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz)
180: #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz)
181: #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz)
182:
183: /*
184: * Interface to ld.so
185: */
186: struct crt_ldso {
187: int crt_ba; /* Base address of ld.so */
188: int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */
189: int crt_ldfd; /* ld.so file descriptor */
190: struct _dynamic *crt_dp; /* Main's __DYNAMIC */
191: char **crt_ep; /* environment strings */
192: caddr_t crt_bp; /* Breakpoint if run from debugger */
193: char *crt_prog; /* Program name (v3) */
194: char *crt_ldso; /* Link editor name (v4) */
195: struct ld_entry *crt_ldentry; /* dl*() access (v4) */
196: };
197:
198: /*
199: * Version passed from crt0 to ld.so (1st argument to _rtld()).
200: */
201: #define CRT_VERSION_SUN 1
202: #define CRT_VERSION_BSD_2 2
203: #define CRT_VERSION_BSD_3 3
204: #define CRT_VERSION_BSD_4 4
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