link_aout.h revision 1.5
1/* $NetBSD: link_aout.h,v 1.5 1994/10/26 00:56:01 cgd 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 51struct 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 */ 66struct 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 */ 84struct 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_RESERVED(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 2 102 103 104/* 105 * The `section_dispatch_table' structure contains offsets to various data 106 * structures needed to do run-time relocation. 107 */ 108struct section_dispatch_table { 109 struct so_map *sdt_loaded; /* List of loaded objects */ 110 long sdt_sods; /* List of shared objects descriptors */ 111 long sdt_filler1; /* Unused (was: search rules) */ 112 long sdt_got; /* Global offset table */ 113 long sdt_plt; /* Procedure linkage table */ 114 long sdt_rel; /* Relocation table */ 115 long sdt_hash; /* Symbol hash table */ 116 long sdt_nzlist; /* Symbol table itself */ 117 long sdt_filler2; /* Unused (was: stab_hash) */ 118 long sdt_buckets; /* Number of hash buckets */ 119 long sdt_strings; /* Symbol strings */ 120 long sdt_str_sz; /* Size of symbol strings */ 121 long sdt_text_sz; /* Size of text area */ 122 long sdt_plt_sz; /* Size of procedure linkage table */ 123}; 124 125/* 126 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 127 * Used to quickly lookup symbols of the shared object by hashing 128 * on the symbol's name. `rh_symbolnum' is the index of the symbol 129 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 130 * the next symbol in the hash bucket (in case of collisions). 131 */ 132struct rrs_hash { 133 int rh_symbolnum; /* Symbol number */ 134 int rh_next; /* Next hash entry */ 135}; 136 137/* 138 * `rt_symbols' is used to keep track of run-time allocated commons 139 * and data items copied from shared objects. 140 */ 141struct rt_symbol { 142 struct nzlist *rt_sp; /* The symbol */ 143 struct rt_symbol *rt_next; /* Next in linear list */ 144 struct rt_symbol *rt_link; /* Next in bucket */ 145 caddr_t rt_srcaddr; /* Address of "master" copy */ 146 struct so_map *rt_smp; /* Originating map */ 147}; 148 149/* 150 * Debugger interface structure. 151 */ 152struct so_debug { 153 int dd_version; /* Version # of interface */ 154 int dd_in_debugger; /* Set when run by debugger */ 155 int dd_sym_loaded; /* Run-time linking brought more 156 symbols into scope */ 157 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 158 int dd_bpt_shadow; /* Original contents of bpt */ 159 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 160}; 161 162/* 163 * Entry points into ld.so - user interface to the run-time linker. 164 */ 165struct ld_entry { 166 void *(*dlopen) __P((char *, int)); 167 int (*dlclose) __P((void *)); 168 void *(*dlsym) __P((void *, char *)); 169 int (*dlctl) __P((void *, int, void *)); 170}; 171 172/* 173 * dlctl() commands 174 */ 175#define DL_GETERRNO 1 176#define DL_SETSRCHPATH x 177#define DL_GETLIST x 178#define DL_GETREFCNT x 179#define DL_GETLOADADDR x 180 181/* 182 * dl*() prototypes. 183 */ 184extern void *dlopen __P((char *, int)); 185extern int dlclose __P((void *)); 186extern void *dlsym __P((void *, char *)); 187extern int dlctl __P((void *, int, void *)); 188 189 190/* 191 * This is the structure pointed at by the __DYNAMIC symbol if an 192 * executable requires the attention of the run-time link editor. 193 * __DYNAMIC is given the value zero if no run-time linking needs to 194 * be done (it is always present in shared objects). 195 * The union `d_un' provides for different versions of the dynamic 196 * linking mechanism (switched on by `d_version'). The last version 197 * used by Sun is 3. We leave some room here and go to version number 198 * 8 for NetBSD, the main difference lying in the support for the 199 * `nz_list' type of symbols. 200 */ 201 202struct _dynamic { 203 int d_version; /* version # of this interface */ 204 struct so_debug *d_debug; 205 union { 206 struct section_dispatch_table *d_sdt; 207 } d_un; 208 struct ld_entry *d_entry; 209}; 210 211#define LD_VERSION_SUN (3) 212#define LD_VERSION_BSD (8) 213#define LD_VERSION_NZLIST_P(v) ((v) >= 8) 214 215#define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 216#define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 217#define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 218#define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 219#define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 220#define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 221#define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 222#define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 223 224#define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 225#define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 226#define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 227#define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 228#define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 229#define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 230#define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 231 232/* 233 * Interface to ld.so 234 */ 235struct crt_ldso { 236 int crt_ba; /* Base address of ld.so */ 237 int crt_dzfd; /* "/dev/zero" file decriptor (SunOS) */ 238 int crt_ldfd; /* ld.so file descriptor */ 239 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 240 char **crt_ep; /* environment strings */ 241 caddr_t crt_bp; /* Breakpoint if run from debugger */ 242 char *crt_prog; /* Program name */ 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 3 251 252 253/* 254 * Maximum number of recognized shared object version numbers. 255 */ 256#define MAXDEWEY 8 257 258/* 259 * Header of the hints file. 260 */ 261struct hints_header { 262 long hh_magic; 263#define HH_MAGIC 011421044151 264 long hh_version; /* Interface version number */ 265#define LD_HINTS_VERSION_1 1 266 long hh_hashtab; /* Location of hash table */ 267 long hh_nbucket; /* Number of buckets in hashtab */ 268 long hh_strtab; /* Location of strings */ 269 long hh_strtab_sz; /* Size of strings */ 270 long hh_ehints; /* End of hints (max offset in file) */ 271}; 272 273#define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 274 275/* 276 * Hash table element in hints file. 277 */ 278struct hints_bucket { 279 /* namex and pathx are indices into the string table */ 280 int hi_namex; /* Library name */ 281 int hi_pathx; /* Full path */ 282 int hi_dewey[MAXDEWEY]; /* The versions */ 283 int hi_ndewey; /* Number of version numbers */ 284#define hi_major hi_dewey[0] 285#define hi_minor hi_dewey[1] 286 int hi_next; /* Next in this bucket */ 287}; 288 289#define _PATH_LD_HINTS "/var/run/ld.so.hints" 290 291#endif /* _LINK_H_ */ 292 293