Annotation of src/include/link.h, Revision 1.7
1.7 ! art 1: /* $OpenBSD: link.h,v 1.6 2001/05/31 14:04:52 art 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
20: * derived from this software withough specific prior written permission
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:
1.7 ! art 45: #include <sys/exec_elf.h>
! 46:
1.6 art 47: /* XXXART - ? */
48: #ifndef DT_PROCNUM
49: #define DT_PROCNUM 0
50: #endif
1.1 deraadt 51:
52: /*
1.4 espie 53: * A `Shared Object Descriptor' describes a shared object that is needed
1.1 deraadt 54: * to complete the link edit process of the object containing it.
55: * A list of such objects (chained through `sod_next') is pointed at
56: * by `sdt_sods' in the section_dispatch_table structure.
57: */
58:
59: struct sod { /* Shared Object Descriptor */
60: long sod_name; /* name (relative to load address) */
61: u_int sod_library : 1, /* Searched for by library rules */
62: sod_reserved : 31;
63: short sod_major; /* major version number */
64: short sod_minor; /* minor version number */
65: long sod_next; /* next sod */
66: };
67:
68: /*
69: * `Shared Object Map's are used by the run-time link editor (ld.so) to
70: * keep track of all shared objects loaded into a process' address space.
71: * These structures are only used at run-time and do not occur within
72: * the text or data segment of an executable or shared library.
73: */
74: struct so_map { /* Shared Object Map */
75: caddr_t som_addr; /* Address at which object mapped */
76: char *som_path; /* Path to mmap'ed file */
77: struct so_map *som_next; /* Next map in chain */
78: struct sod *som_sod; /* Sod responsible for this map */
79: caddr_t som_sodbase; /* Base address of this sod */
80: u_int som_write : 1; /* Text is currently writable */
81: struct _dynamic *som_dynamic; /* _dynamic structure */
82: caddr_t som_spd; /* Private data */
83: };
84:
85: /*
86: * Symbol description with size. This is simply an `nlist' with
87: * one field (nz_size) added.
88: * Used to convey size information on items in the data segment
89: * of shared objects. An array of these live in the shared object's
90: * text segment and is addressed by the `sdt_nzlist' field.
91: */
92: struct nzlist {
93: struct nlist nlist;
94: u_long nz_size;
95: #define nz_un nlist.n_un
96: #define nz_strx nlist.n_un.n_strx
97: #define nz_name nlist.n_un.n_name
98: #define nz_type nlist.n_type
99: #define nz_value nlist.n_value
100: #define nz_desc nlist.n_desc
101: #define nz_other nlist.n_other
102: };
103:
104: #define N_AUX(p) ((p)->n_other & 0xf)
105: #define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf)
106: #define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf))
107:
108: #define AUX_OBJECT 1
109: #define AUX_FUNC 2
110: /*#define BIND_LOCAL 0 not used */
111: /*#define BIND_GLOBAL 1 not used */
112: #define BIND_WEAK 2
113:
114:
115: /*
116: * The `section_dispatch_table' structure contains offsets to various data
117: * structures needed to do run-time relocation.
118: */
119: struct section_dispatch_table {
120: struct so_map *sdt_loaded; /* List of loaded objects */
121: long sdt_sods; /* List of shared objects descriptors */
122: long sdt_paths; /* Library search paths */
123: long sdt_got; /* Global offset table */
124: long sdt_plt; /* Procedure linkage table */
125: long sdt_rel; /* Relocation table */
126: long sdt_hash; /* Symbol hash table */
127: long sdt_nzlist; /* Symbol table itself */
128: long sdt_filler2; /* Unused (was: stab_hash) */
129: long sdt_buckets; /* Number of hash buckets */
130: long sdt_strings; /* Symbol strings */
131: long sdt_str_sz; /* Size of symbol strings */
132: long sdt_text_sz; /* Size of text area */
133: long sdt_plt_sz; /* Size of procedure linkage table */
134: };
135:
136: /*
137: * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table.
138: * Used to quickly lookup symbols of the shared object by hashing
139: * on the symbol's name. `rh_symbolnum' is the index of the symbol
140: * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is
141: * the next symbol in the hash bucket (in case of collisions).
142: */
143: struct rrs_hash {
144: int rh_symbolnum; /* Symbol number */
145: int rh_next; /* Next hash entry */
146: };
147:
148: /*
149: * `rt_symbols' is used to keep track of run-time allocated commons
150: * and data items copied from shared objects.
151: */
152: struct rt_symbol {
153: struct nzlist *rt_sp; /* The symbol */
154: struct rt_symbol *rt_next; /* Next in linear list */
155: struct rt_symbol *rt_link; /* Next in bucket */
156: caddr_t rt_srcaddr; /* Address of "master" copy */
157: struct so_map *rt_smp; /* Originating map */
158: };
159:
160: /*
161: * Debugger interface structure.
162: */
163: struct so_debug {
164: int dd_version; /* Version # of interface */
165: int dd_in_debugger; /* Set when run by debugger */
166: int dd_sym_loaded; /* Run-time linking brought more
167: symbols into scope */
168: char *dd_bpt_addr; /* Address of rtld-generated bpt */
169: int dd_bpt_shadow; /* Original contents of bpt */
170: struct rt_symbol *dd_cc; /* Allocated commons/copied data */
171: };
1.7 ! art 172:
! 173: /*
! 174: * Debug rendezvous struct. Pointer to this is set up in the
! 175: * target code pointed by the DT_MIPS_RLD_MAP tag. If it is
! 176: * defined.
! 177: */
! 178:
! 179: struct r_debug {
! 180: int r_version; /* Protocol version. */
! 181: struct link_map *r_map; /* Head of list of loaded objects. */
! 182:
! 183: /*
! 184: * This is the address of a function internal to the run-time linker,
! 185: * that will always be called when the linker begins to map in a
! 186: * library or unmap it, and again when the mapping change is complete.
! 187: * The debugger can set a breakpoint at this address if it wants to
! 188: * notice shared object mapping changes.
! 189: */
! 190: Elf_Addr r_brk;
! 191: enum {
! 192: /*
! 193: * This state value describes the mapping change taking place
! 194: * when the `r_brk' address is called.
! 195: */
! 196: RT_CONSISTENT, /* Mapping change is complete. */
! 197: RT_ADD, /* Adding a new object. */
! 198: RT_DELETE, /* Removing an object mapping. */
! 199: } r_state;
! 200:
! 201: Elf_Addr r_ldbase; /* Base address the linker is loaded at. */
! 202: };
! 203:
1.1 deraadt 204:
205: /*
206: * Entry points into ld.so - user interface to the run-time linker.
207: */
208: struct ld_entry {
1.5 espie 209: void *(*dlopen) __P((const char *, int));
1.1 deraadt 210: int (*dlclose) __P((void *));
1.5 espie 211: void *(*dlsym) __P((void *, const char *));
1.1 deraadt 212: int (*dlctl) __P((void *, int, void *));
213: void (*dlexit) __P((void));
214: void (*dlrsrvd[3]) __P((void));
215: };
216:
217: /*
218: * This is the structure pointed at by the __DYNAMIC symbol if an
219: * executable requires the attention of the run-time link editor.
220: * __DYNAMIC is given the value zero if no run-time linking needs to
221: * be done (it is always present in shared objects).
222: * The union `d_un' provides for different versions of the dynamic
223: * linking mechanism (switched on by `d_version'). The last version
224: * used by Sun is 3. We leave some room here and go to version number
225: * 8 for NetBSD, the main difference lying in the support for the
226: * `nz_list' type of symbols.
227: */
228:
229: struct _dynamic {
230: int d_version; /* version # of this interface */
231: struct so_debug *d_debug;
232: union {
233: struct section_dispatch_table *d_sdt;
234: } d_un;
235: struct ld_entry *d_entry; /* compat - now in crt_ldso */
236: };
237:
238: #define LD_VERSION_SUN (3)
239: #define LD_VERSION_BSD (8)
240: #define LD_VERSION_NZLIST_P(v) ((v) >= 8)
241:
242: #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got)
243: #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt)
244: #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel)
245: #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist)
246: #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash)
247: #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings)
248: #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods)
249: #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets)
250: #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths)
251:
252: #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got)
253: #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel)
254: #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash)
255: #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist)
256: #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz)
257: #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz)
258: #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz)
259:
260: /*
261: * Interface to ld.so
262: */
263: struct crt_ldso {
264: int crt_ba; /* Base address of ld.so */
265: int crt_dzfd; /* "/dev/zero" file decriptor (SunOS) */
266: int crt_ldfd; /* ld.so file descriptor */
267: struct _dynamic *crt_dp; /* Main's __DYNAMIC */
268: char **crt_ep; /* environment strings */
269: caddr_t crt_bp; /* Breakpoint if run from debugger */
270: char *crt_prog; /* Program name (v3) */
271: char *crt_ldso; /* Link editor name (v4) */
272: struct ld_entry *crt_ldentry; /* dl*() access (v4) */
273: };
274:
275: /*
276: * Version passed from crt0 to ld.so (1st argument to _rtld()).
277: */
278: #define CRT_VERSION_SUN 1
279: #define CRT_VERSION_BSD_2 2
280: #define CRT_VERSION_BSD_3 3
281: #define CRT_VERSION_BSD_4 4
282:
283:
284: /*
285: * Maximum number of recognized shared object version numbers.
286: */
287: #define MAXDEWEY 8
288:
289: /*
290: * Header of the hints file.
291: */
292: struct hints_header {
293: long hh_magic;
294: #define HH_MAGIC 011421044151
295: long hh_version; /* Interface version number */
296: #define LD_HINTS_VERSION_1 1
1.2 deraadt 297: #define LD_HINTS_VERSION_2 2
1.1 deraadt 298: long hh_hashtab; /* Location of hash table */
299: long hh_nbucket; /* Number of buckets in hashtab */
300: long hh_strtab; /* Location of strings */
301: long hh_strtab_sz; /* Size of strings */
302: long hh_ehints; /* End of hints (max offset in file) */
1.2 deraadt 303: long hh_dirlist; /* Colon-separated list of srch dirs */
1.1 deraadt 304: };
305:
306: #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC)
307:
308: /*
309: * Hash table element in hints file.
310: */
311: struct hints_bucket {
312: /* namex and pathx are indices into the string table */
313: int hi_namex; /* Library name */
314: int hi_pathx; /* Full path */
315: int hi_dewey[MAXDEWEY]; /* The versions */
316: int hi_ndewey; /* Number of version numbers */
317: #define hi_major hi_dewey[0]
318: #define hi_minor hi_dewey[1]
319: int hi_next; /* Next in this bucket */
320: };
321:
322: #define _PATH_LD_HINTS "/var/run/ld.so.hints"
323:
324: #endif /* _LINK_H_ */
325:
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