1 /* $NetBSD: link_aout.h,v 1.19 2000/09/14 20:36:39 wiz 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_AOUT_H_ 48 #define _LINK_AOUT_H_ 49 50 #include <dlfcn.h> /* for Dl_info */ 51 #include <a.out.h> /* for struct nlist */ 52 53 /* 54 * A `Shared Object Descriptor' describes a shared object that is needed 55 * to complete the link edit process of the object containing it. 56 * A list of such objects (chained through `sod_next') is pointed at 57 * by `sdt_sods' in the section_dispatch_table structure. 58 */ 59 60 struct sod { /* Shared Object Descriptor */ 61 long sod_name; /* name (relative to load address) */ 62 u_int sod_library : 1, /* Searched for by library rules */ 63 sod_reserved : 31; 64 short sod_major; /* major version number */ 65 short sod_minor; /* minor version number */ 66 long sod_next; /* next sod */ 67 }; 68 69 /* 70 * `Shared Object Map's are used by the run-time link editor (ld.so) to 71 * keep track of all shared objects loaded into a process' address space. 72 * These structures are only used at run-time and do not occur within 73 * the text or data segment of an executable or shared library. 74 */ 75 struct so_map { /* Shared Object Map */ 76 caddr_t som_addr; /* Address at which object mapped */ 77 char *som_path; /* Path to mmap'ed file */ 78 struct so_map *som_next; /* Next map in chain */ 79 struct sod *som_sod; /* Sod responsible for this map */ 80 caddr_t som_sodbase; /* Base address of this sod */ 81 u_int som_write : 1; /* Text is currently writable */ 82 struct _dynamic *som_dynamic; /* _dynamic structure */ 83 caddr_t som_spd; /* Private data */ 84 }; 85 86 /* 87 * Symbol description with size. This is simply an `nlist' with 88 * one field (nz_size) added. 89 * Used to convey size information on items in the data segment 90 * of shared objects. An array of these live in the shared object's 91 * text segment and is addressed by the `sdt_nzlist' field. 92 */ 93 struct nzlist { 94 struct nlist nlist; 95 u_long nz_size; 96 #define nz_un nlist.n_un 97 #define nz_strx nlist.n_un.n_strx 98 #define nz_name nlist.n_un.n_name 99 #define nz_type nlist.n_type 100 #define nz_value nlist.n_value 101 #define nz_desc nlist.n_desc 102 #define nz_other nlist.n_other 103 }; 104 105 #define N_AUX(p) ((p)->n_other & 0xf) 106 #define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf) 107 #define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf)) 108 109 #define AUX_OBJECT 1 110 #define AUX_FUNC 2 111 #define AUX_LABEL 3 112 /*#define BIND_LOCAL 0 not used */ 113 /*#define BIND_GLOBAL 1 not used */ 114 #define BIND_WEAK 2 115 116 117 /* 118 * The `section_dispatch_table' structure contains offsets to various data 119 * structures needed to do run-time relocation. 120 */ 121 struct section_dispatch_table { 122 struct so_map *sdt_loaded; /* List of loaded objects */ 123 long sdt_sods; /* List of shared objects descriptors */ 124 long sdt_paths; /* Library search paths */ 125 long sdt_got; /* Global offset table */ 126 long sdt_plt; /* Procedure linkage table */ 127 long sdt_rel; /* Relocation table */ 128 long sdt_hash; /* Symbol hash table */ 129 long sdt_nzlist; /* Symbol table itself */ 130 long sdt_filler2; /* Unused (was: stab_hash) */ 131 long sdt_buckets; /* Number of hash buckets */ 132 long sdt_strings; /* Symbol strings */ 133 long sdt_str_sz; /* Size of symbol strings */ 134 long sdt_text_sz; /* Size of text area */ 135 long sdt_plt_sz; /* Size of procedure linkage table */ 136 }; 137 138 /* 139 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 140 * Used to quickly lookup symbols of the shared object by hashing 141 * on the symbol's name. `rh_symbolnum' is the index of the symbol 142 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 143 * the next symbol in the hash bucket (in case of collisions). 144 */ 145 struct rrs_hash { 146 int rh_symbolnum; /* Symbol number */ 147 int rh_next; /* Next hash entry */ 148 }; 149 150 /* 151 * `rt_symbols' is used to keep track of run-time allocated commons 152 * and data items copied from shared objects. 153 */ 154 struct rt_symbol { 155 struct nzlist *rt_sp; /* The symbol */ 156 struct rt_symbol *rt_next; /* Next in linear list */ 157 struct rt_symbol *rt_link; /* Next in bucket */ 158 caddr_t rt_srcaddr; /* Address of "master" copy */ 159 struct so_map *rt_smp; /* Originating map */ 160 }; 161 162 /* 163 * Debugger interface structure. 164 */ 165 struct so_debug { 166 int dd_version; /* Version # of interface */ 167 int dd_in_debugger; /* Set when run by debugger */ 168 int dd_sym_loaded; /* Run-time linking brought more 169 symbols into scope */ 170 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 171 int dd_bpt_shadow; /* Original contents of bpt */ 172 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 173 }; 174 175 /* 176 * Entry points into ld.so - user interface to the run-time linker. 177 */ 178 struct ld_entry { 179 void *(*dlopen) __P((const char *, int)); 180 int (*dlclose) __P((void *)); 181 void *(*dlsym) __P((void *, const char *)); 182 int (*dlctl) __P((void *, int, void *)); 183 void (*dlexit) __P((void)); 184 int (*dladdr) __P((const void *, Dl_info *)); 185 void (*dlrsrvd[2]) __P((void)); 186 }; 187 188 /* 189 * This is the structure pointed at by the __DYNAMIC symbol if an 190 * executable requires the attention of the run-time link editor. 191 * __DYNAMIC is given the value zero if no run-time linking needs to 192 * be done (it is always present in shared objects). 193 * The union `d_un' provides for different versions of the dynamic 194 * linking mechanism (switched on by `d_version'). The last version 195 * used by Sun is 3. We leave some room here and go to version number 196 * 8 for NetBSD, the main difference lying in the support for the 197 * `nz_list' type of symbols. 198 */ 199 200 struct _dynamic { 201 int d_version; /* version # of this interface */ 202 struct so_debug *d_debug; 203 union { 204 struct section_dispatch_table *d_sdt; 205 } d_un; 206 struct ld_entry *d_entry; /* compat - now in crt_ldso */ 207 }; 208 209 #define LD_VERSION_SUN (3) 210 #define LD_VERSION_BSD (8) 211 #define LD_VERSION_NZLIST_P(v) ((v) >= 8) 212 213 #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 214 #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 215 #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 216 #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 217 #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 218 #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 219 #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 220 #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 221 #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths) 222 223 #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 224 #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 225 #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 226 #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 227 #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 228 #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 229 #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 230 231 /* 232 * Interface to ld.so 233 */ 234 struct crt_ldso { 235 int crt_ba; /* Base address of ld.so */ 236 int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */ 237 int crt_ldfd; /* ld.so file descriptor */ 238 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 239 char **crt_ep; /* environment strings */ 240 caddr_t crt_bp; /* Breakpoint if run from debugger */ 241 char *crt_prog; /* Program name (v3) */ 242 char *crt_ldso; /* Link editor name (v4) */ 243 struct ld_entry *crt_ldentry; /* dl*() access (v4) */ 244 }; 245 246 /* 247 * Version passed from crt0 to ld.so (1st argument to _rtld()). 248 */ 249 #define CRT_VERSION_SUN 1 250 #define CRT_VERSION_BSD_2 2 251 #define CRT_VERSION_BSD_3 3 252 #define CRT_VERSION_BSD_4 4 253 254 255 /* 256 * Maximum number of recognized shared object version numbers. 257 */ 258 #define MAXDEWEY 8 259 260 /* 261 * Header of the hints file. 262 */ 263 struct hints_header { 264 long hh_magic; 265 #define HH_MAGIC 011421044151 266 long hh_version; /* Interface version number */ 267 #define LD_HINTS_VERSION_1 1 268 #define LD_HINTS_VERSION_2 2 269 long hh_hashtab; /* Location of hash table */ 270 long hh_nbucket; /* Number of buckets in hashtab */ 271 long hh_strtab; /* Location of strings */ 272 long hh_strtab_sz; /* Size of strings */ 273 long hh_ehints; /* End of hints (max offset in file) */ 274 long hh_dirlist; /* Colon-separated list of srch dirs */ 275 }; 276 277 #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 278 279 /* 280 * Hash table element in hints file. 281 */ 282 struct hints_bucket { 283 /* namex and pathx are indices into the string table */ 284 int hi_namex; /* Library name */ 285 int hi_pathx; /* Full path */ 286 int hi_dewey[MAXDEWEY]; /* The versions */ 287 int hi_ndewey; /* Number of version numbers */ 288 #define hi_major hi_dewey[0] 289 #define hi_minor hi_dewey[1] 290 int hi_next; /* Next in this bucket */ 291 }; 292 293 #define _PATH_LD_HINTS "/var/run/ld.so.hints" 294 295 #endif /* _LINK_AOUT_H_ */ 296