link_aout.h revision 1.15
1/* $NetBSD: link_aout.h,v 1.15 1998/10/19 00:30:57 matt Exp $ */ 2 3/*- 4 * Copyright (c) 1998 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Paul Kranenburg. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the NetBSD 21 * Foundation, Inc. and its contributors. 22 * 4. Neither the name of The NetBSD Foundation nor the names of its 23 * contributors may be used to endorse or promote products derived 24 * from this software without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 27 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 28 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 29 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 30 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 31 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 32 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 33 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 34 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 35 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 36 * POSSIBILITY OF SUCH DAMAGE. 37 */ 38 39/* 40 * RRS section definitions. 41 * 42 * The layout of some data structures defined in this header file is 43 * such that we can provide compatibility with the SunOS 4.x shared 44 * library scheme. 45 */ 46 47#ifndef _LINK_H_ 48#define _LINK_H_ 49 50#include <dlfcn.h> /* for Dl_info */ 51 52/* 53 * A `Shared Object Descriptor' descibes a shared object that is needed 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 59struct 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 */ 74struct 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 */ 92struct 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 AUX_LABEL 3 111/*#define BIND_LOCAL 0 not used */ 112/*#define BIND_GLOBAL 1 not used */ 113#define BIND_WEAK 2 114 115 116/* 117 * The `section_dispatch_table' structure contains offsets to various data 118 * structures needed to do run-time relocation. 119 */ 120struct section_dispatch_table { 121 struct so_map *sdt_loaded; /* List of loaded objects */ 122 long sdt_sods; /* List of shared objects descriptors */ 123 long sdt_paths; /* Library search paths */ 124 long sdt_got; /* Global offset table */ 125 long sdt_plt; /* Procedure linkage table */ 126 long sdt_rel; /* Relocation table */ 127 long sdt_hash; /* Symbol hash table */ 128 long sdt_nzlist; /* Symbol table itself */ 129 long sdt_filler2; /* Unused (was: stab_hash) */ 130 long sdt_buckets; /* Number of hash buckets */ 131 long sdt_strings; /* Symbol strings */ 132 long sdt_str_sz; /* Size of symbol strings */ 133 long sdt_text_sz; /* Size of text area */ 134 long sdt_plt_sz; /* Size of procedure linkage table */ 135}; 136 137/* 138 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 139 * Used to quickly lookup symbols of the shared object by hashing 140 * on the symbol's name. `rh_symbolnum' is the index of the symbol 141 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 142 * the next symbol in the hash bucket (in case of collisions). 143 */ 144struct rrs_hash { 145 int rh_symbolnum; /* Symbol number */ 146 int rh_next; /* Next hash entry */ 147}; 148 149/* 150 * `rt_symbols' is used to keep track of run-time allocated commons 151 * and data items copied from shared objects. 152 */ 153struct rt_symbol { 154 struct nzlist *rt_sp; /* The symbol */ 155 struct rt_symbol *rt_next; /* Next in linear list */ 156 struct rt_symbol *rt_link; /* Next in bucket */ 157 caddr_t rt_srcaddr; /* Address of "master" copy */ 158 struct so_map *rt_smp; /* Originating map */ 159}; 160 161/* 162 * Debugger interface structure. 163 */ 164struct so_debug { 165 int dd_version; /* Version # of interface */ 166 int dd_in_debugger; /* Set when run by debugger */ 167 int dd_sym_loaded; /* Run-time linking brought more 168 symbols into scope */ 169 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 170 int dd_bpt_shadow; /* Original contents of bpt */ 171 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 172}; 173 174/* 175 * Entry points into ld.so - user interface to the run-time linker. 176 */ 177struct ld_entry { 178 void *(*dlopen) __P((const char *, int)); 179 int (*dlclose) __P((void *)); 180 void *(*dlsym) __P((void *, const char *)); 181 int (*dlctl) __P((void *, int, void *)); 182 void (*dlexit) __P((void)); 183 int (*dladdr) __P((void *, Dl_info *)); 184 void (*dlrsrvd[2]) __P((void)); 185}; 186 187/* 188 * This is the structure pointed at by the __DYNAMIC symbol if an 189 * executable requires the attention of the run-time link editor. 190 * __DYNAMIC is given the value zero if no run-time linking needs to 191 * be done (it is always present in shared objects). 192 * The union `d_un' provides for different versions of the dynamic 193 * linking mechanism (switched on by `d_version'). The last version 194 * used by Sun is 3. We leave some room here and go to version number 195 * 8 for NetBSD, the main difference lying in the support for the 196 * `nz_list' type of symbols. 197 */ 198 199struct _dynamic { 200 int d_version; /* version # of this interface */ 201 struct so_debug *d_debug; 202 union { 203 struct section_dispatch_table *d_sdt; 204 } d_un; 205 struct ld_entry *d_entry; /* compat - now in crt_ldso */ 206}; 207 208#define LD_VERSION_SUN (3) 209#define LD_VERSION_BSD (8) 210#define LD_VERSION_NZLIST_P(v) ((v) >= 8) 211 212#define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 213#define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 214#define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 215#define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 216#define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 217#define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 218#define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 219#define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 220#define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths) 221 222#define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 223#define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 224#define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 225#define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 226#define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 227#define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 228#define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 229 230/* 231 * Interface to ld.so 232 */ 233struct crt_ldso { 234 int crt_ba; /* Base address of ld.so */ 235 int crt_dzfd; /* "/dev/zero" file decriptor (SunOS) */ 236 int crt_ldfd; /* ld.so file descriptor */ 237 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 238 char **crt_ep; /* environment strings */ 239 caddr_t crt_bp; /* Breakpoint if run from debugger */ 240 char *crt_prog; /* Program name (v3) */ 241 char *crt_ldso; /* Link editor name (v4) */ 242 struct ld_entry *crt_ldentry; /* dl*() access (v4) */ 243}; 244 245/* 246 * Version passed from crt0 to ld.so (1st argument to _rtld()). 247 */ 248#define CRT_VERSION_SUN 1 249#define CRT_VERSION_BSD_2 2 250#define CRT_VERSION_BSD_3 3 251#define CRT_VERSION_BSD_4 4 252 253 254/* 255 * Maximum number of recognized shared object version numbers. 256 */ 257#define MAXDEWEY 8 258 259/* 260 * Header of the hints file. 261 */ 262struct hints_header { 263 long hh_magic; 264#define HH_MAGIC 011421044151 265 long hh_version; /* Interface version number */ 266#define LD_HINTS_VERSION_1 1 267#define LD_HINTS_VERSION_2 2 268 long hh_hashtab; /* Location of hash table */ 269 long hh_nbucket; /* Number of buckets in hashtab */ 270 long hh_strtab; /* Location of strings */ 271 long hh_strtab_sz; /* Size of strings */ 272 long hh_ehints; /* End of hints (max offset in file) */ 273 long hh_dirlist; /* Colon-separated list of srch dirs */ 274}; 275 276#define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 277 278/* 279 * Hash table element in hints file. 280 */ 281struct hints_bucket { 282 /* namex and pathx are indices into the string table */ 283 int hi_namex; /* Library name */ 284 int hi_pathx; /* Full path */ 285 int hi_dewey[MAXDEWEY]; /* The versions */ 286 int hi_ndewey; /* Number of version numbers */ 287#define hi_major hi_dewey[0] 288#define hi_minor hi_dewey[1] 289 int hi_next; /* Next in this bucket */ 290}; 291 292#define _PATH_LD_HINTS "/var/run/ld.so.hints" 293 294#endif /* _LINK_H_ */ 295 296