1 /* $NetBSD: link_aout.h,v 1.23 2016/01/23 01:26:14 dholland 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 /* 33 * RRS section definitions. 34 * 35 * The layout of some data structures defined in this header file is 36 * such that we can provide compatibility with the SunOS 4.x shared 37 * library scheme. 38 */ 39 40 #ifndef _LINK_AOUT_H_ 41 #define _LINK_AOUT_H_ 42 43 #include <dlfcn.h> /* for Dl_info */ 44 #include <a.out.h> /* for struct nlist */ 45 46 /* 47 * A `Shared Object Descriptor' describes a shared object that is needed 48 * to complete the link edit process of the object containing it. 49 * A list of such objects (chained through `sod_next') is pointed at 50 * by `sdt_sods' in the section_dispatch_table structure. 51 */ 52 53 struct sod { /* Shared Object Descriptor */ 54 long sod_name; /* name (relative to load address) */ 55 unsigned int sod_library : 1, /* Searched for by library rules */ 56 sod_reserved : 31; 57 short sod_major; /* major version number */ 58 short sod_minor; /* minor version number */ 59 long sod_next; /* next sod */ 60 }; 61 62 /* 63 * `Shared Object Map's are used by the run-time link editor (ld.so) to 64 * keep track of all shared objects loaded into a process' address space. 65 * These structures are only used at run-time and do not occur within 66 * the text or data segment of an executable or shared library. 67 */ 68 struct so_map { /* Shared Object Map */ 69 caddr_t som_addr; /* Address at which object mapped */ 70 char *som_path; /* Path to mmap'ed file */ 71 struct so_map *som_next; /* Next map in chain */ 72 struct sod *som_sod; /* Sod responsible for this map */ 73 caddr_t som_sodbase; /* Base address of this sod */ 74 unsigned int som_write : 1; /* Text is currently writable */ 75 struct _dynamic *som_dynamic; /* _dynamic structure */ 76 caddr_t som_spd; /* Private data */ 77 }; 78 79 /* 80 * Symbol description with size. This is simply an `nlist' with 81 * one field (nz_size) added. 82 * Used to convey size information on items in the data segment 83 * of shared objects. An array of these live in the shared object's 84 * text segment and is addressed by the `sdt_nzlist' field. 85 */ 86 struct nzlist { 87 struct nlist nlist; 88 unsigned long nz_size; 89 #define nz_un nlist.n_un 90 #define nz_strx nlist.n_un.n_strx 91 #define nz_name nlist.n_un.n_name 92 #define nz_type nlist.n_type 93 #define nz_value nlist.n_value 94 #define nz_desc nlist.n_desc 95 #define nz_other nlist.n_other 96 }; 97 98 #define N_AUX(p) ((p)->n_other & 0xf) 99 #define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf) 100 #define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf)) 101 102 #define AUX_OBJECT 1 103 #define AUX_FUNC 2 104 #define AUX_LABEL 3 105 /*#define BIND_LOCAL 0 not used */ 106 /*#define BIND_GLOBAL 1 not used */ 107 #define BIND_WEAK 2 108 109 110 /* 111 * The `section_dispatch_table' structure contains offsets to various data 112 * structures needed to do run-time relocation. 113 */ 114 struct section_dispatch_table { 115 struct so_map *sdt_loaded; /* List of loaded objects */ 116 long sdt_sods; /* List of shared objects descriptors */ 117 long sdt_paths; /* Library search paths */ 118 long sdt_got; /* Global offset table */ 119 long sdt_plt; /* Procedure linkage table */ 120 long sdt_rel; /* Relocation table */ 121 long sdt_hash; /* Symbol hash table */ 122 long sdt_nzlist; /* Symbol table itself */ 123 long sdt_filler2; /* Unused (was: stab_hash) */ 124 long sdt_buckets; /* Number of hash buckets */ 125 long sdt_strings; /* Symbol strings */ 126 long sdt_str_sz; /* Size of symbol strings */ 127 long sdt_text_sz; /* Size of text area */ 128 long sdt_plt_sz; /* Size of procedure linkage table */ 129 }; 130 131 /* 132 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 133 * Used to quickly lookup symbols of the shared object by hashing 134 * on the symbol's name. `rh_symbolnum' is the index of the symbol 135 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 136 * the next symbol in the hash bucket (in case of collisions). 137 */ 138 struct rrs_hash { 139 int rh_symbolnum; /* Symbol number */ 140 int rh_next; /* Next hash entry */ 141 }; 142 143 /* 144 * `rt_symbols' is used to keep track of run-time allocated commons 145 * and data items copied from shared objects. 146 */ 147 struct rt_symbol { 148 struct nzlist *rt_sp; /* The symbol */ 149 struct rt_symbol *rt_next; /* Next in linear list */ 150 struct rt_symbol *rt_link; /* Next in bucket */ 151 caddr_t rt_srcaddr; /* Address of "master" copy */ 152 struct so_map *rt_smp; /* Originating map */ 153 }; 154 155 /* 156 * Debugger interface structure. 157 */ 158 struct so_debug { 159 int dd_version; /* Version # of interface */ 160 int dd_in_debugger; /* Set when run by debugger */ 161 int dd_sym_loaded; /* Run-time linking brought more 162 symbols into scope */ 163 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 164 int dd_bpt_shadow; /* Original contents of bpt */ 165 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 166 }; 167 168 /* 169 * Entry points into ld.so - user interface to the run-time linker. 170 */ 171 struct ld_entry { 172 void *(*dlopen)(const char *, int); 173 int (*dlclose)(void *); 174 void *(*dlsym)(void *, const char *); 175 int (*dlctl)(void *, int, void *); 176 void (*dlexit)(void); 177 int (*dladdr)(const void *, Dl_info *); 178 void (*dlrsrvd[2])(void); 179 }; 180 181 /* 182 * This is the structure pointed at by the __DYNAMIC symbol if an 183 * executable requires the attention of the run-time link editor. 184 * __DYNAMIC is given the value zero if no run-time linking needs to 185 * be done (it is always present in shared objects). 186 * The union `d_un' provides for different versions of the dynamic 187 * linking mechanism (switched on by `d_version'). The last version 188 * used by Sun is 3. We leave some room here and go to version number 189 * 8 for NetBSD, the main difference lying in the support for the 190 * `nz_list' type of symbols. 191 */ 192 193 struct _dynamic { 194 int d_version; /* version # of this interface */ 195 struct so_debug *d_debug; 196 union { 197 struct section_dispatch_table *d_sdt; 198 } d_un; 199 struct ld_entry *d_entry; /* compat - now in crt_ldso */ 200 }; 201 202 #define LD_VERSION_SUN (3) 203 #define LD_VERSION_BSD (8) 204 #define LD_VERSION_NZLIST_P(v) ((v) >= 8) 205 206 #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 207 #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 208 #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 209 #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 210 #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 211 #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 212 #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 213 #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 214 #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths) 215 216 #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 217 #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 218 #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 219 #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 220 #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 221 #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 222 #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 223 224 /* 225 * Interface to ld.so 226 */ 227 struct crt_ldso { 228 int crt_ba; /* Base address of ld.so */ 229 int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */ 230 int crt_ldfd; /* ld.so file descriptor */ 231 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 232 char **crt_ep; /* environment strings */ 233 caddr_t crt_bp; /* Breakpoint if run from debugger */ 234 char *crt_prog; /* Program name (v3) */ 235 char *crt_ldso; /* Link editor name (v4) */ 236 struct ld_entry *crt_ldentry; /* dl*() access (v4) */ 237 }; 238 239 /* 240 * Version passed from crt0 to ld.so (1st argument to _rtld()). 241 */ 242 #define CRT_VERSION_SUN 1 243 #define CRT_VERSION_BSD_2 2 244 #define CRT_VERSION_BSD_3 3 245 #define CRT_VERSION_BSD_4 4 246 247 248 /* 249 * Maximum number of recognized shared object version numbers. 250 */ 251 #define MAXDEWEY 8 252 253 /* 254 * Header of the hints file. 255 */ 256 struct hints_header { 257 long hh_magic; 258 #define HH_MAGIC 011421044151 259 long hh_version; /* Interface version number */ 260 #define LD_HINTS_VERSION_1 1 261 #define LD_HINTS_VERSION_2 2 262 long hh_hashtab; /* Location of hash table */ 263 long hh_nbucket; /* Number of buckets in hashtab */ 264 long hh_strtab; /* Location of strings */ 265 long hh_strtab_sz; /* Size of strings */ 266 long hh_ehints; /* End of hints (max offset in file) */ 267 long hh_dirlist; /* Colon-separated list of srch dirs */ 268 }; 269 270 #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 271 272 /* 273 * Hash table element in hints file. 274 */ 275 struct hints_bucket { 276 /* namex and pathx are indices into the string table */ 277 int hi_namex; /* Library name */ 278 int hi_pathx; /* Full path */ 279 int hi_dewey[MAXDEWEY]; /* The versions */ 280 int hi_ndewey; /* Number of version numbers */ 281 #define hi_major hi_dewey[0] 282 #define hi_minor hi_dewey[1] 283 int hi_next; /* Next in this bucket */ 284 }; 285 286 #define _PATH_LD_HINTS "/var/run/ld.so.hints" 287 288 #endif /* _LINK_AOUT_H_ */ 289