1 /* $OpenBSD: link.h,v 1.8 2001/06/08 07:45:18 art Exp $ */ 2 /* $NetBSD: link.h,v 1.10 1996/01/09 00:00:11 pk Exp $ */ 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_ 44 45 /* XXXART - ? */ 46 #ifndef DT_PROCNUM 47 #define DT_PROCNUM 0 48 #endif 49 50 /* 51 * A `Shared Object Descriptor' describes a shared object that is needed 52 * to complete the link edit process of the object containing it. 53 * A list of such objects (chained through `sod_next') is pointed at 54 * by `sdt_sods' in the section_dispatch_table structure. 55 */ 56 57 struct sod { /* Shared Object Descriptor */ 58 long sod_name; /* name (relative to load address) */ 59 u_int sod_library : 1, /* Searched for by library rules */ 60 sod_reserved : 31; 61 short sod_major; /* major version number */ 62 short sod_minor; /* minor version number */ 63 long sod_next; /* next sod */ 64 }; 65 66 /* 67 * `Shared Object Map's are used by the run-time link editor (ld.so) to 68 * keep track of all shared objects loaded into a process' address space. 69 * These structures are only used at run-time and do not occur within 70 * the text or data segment of an executable or shared library. 71 */ 72 struct so_map { /* Shared Object Map */ 73 caddr_t som_addr; /* Address at which object mapped */ 74 char *som_path; /* Path to mmap'ed file */ 75 struct so_map *som_next; /* Next map in chain */ 76 struct sod *som_sod; /* Sod responsible for this map */ 77 caddr_t som_sodbase; /* Base address of this sod */ 78 u_int som_write : 1; /* Text is currently writable */ 79 struct _dynamic *som_dynamic; /* _dynamic structure */ 80 caddr_t som_spd; /* Private data */ 81 }; 82 83 /* 84 * Symbol description with size. This is simply an `nlist' with 85 * one field (nz_size) added. 86 * Used to convey size information on items in the data segment 87 * of shared objects. An array of these live in the shared object's 88 * text segment and is addressed by the `sdt_nzlist' field. 89 */ 90 struct nzlist { 91 struct nlist nlist; 92 u_long nz_size; 93 #define nz_un nlist.n_un 94 #define nz_strx nlist.n_un.n_strx 95 #define nz_name nlist.n_un.n_name 96 #define nz_type nlist.n_type 97 #define nz_value nlist.n_value 98 #define nz_desc nlist.n_desc 99 #define nz_other nlist.n_other 100 }; 101 102 #define N_AUX(p) ((p)->n_other & 0xf) 103 #define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf) 104 #define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf)) 105 106 #define AUX_OBJECT 1 107 #define AUX_FUNC 2 108 /*#define BIND_LOCAL 0 not used */ 109 /*#define BIND_GLOBAL 1 not used */ 110 #define BIND_WEAK 2 111 112 113 /* 114 * The `section_dispatch_table' structure contains offsets to various data 115 * structures needed to do run-time relocation. 116 */ 117 struct section_dispatch_table { 118 struct so_map *sdt_loaded; /* List of loaded objects */ 119 long sdt_sods; /* List of shared objects descriptors */ 120 long sdt_paths; /* Library search paths */ 121 long sdt_got; /* Global offset table */ 122 long sdt_plt; /* Procedure linkage table */ 123 long sdt_rel; /* Relocation table */ 124 long sdt_hash; /* Symbol hash table */ 125 long sdt_nzlist; /* Symbol table itself */ 126 long sdt_filler2; /* Unused (was: stab_hash) */ 127 long sdt_buckets; /* Number of hash buckets */ 128 long sdt_strings; /* Symbol strings */ 129 long sdt_str_sz; /* Size of symbol strings */ 130 long sdt_text_sz; /* Size of text area */ 131 long sdt_plt_sz; /* Size of procedure linkage table */ 132 }; 133 134 /* 135 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 136 * Used to quickly lookup symbols of the shared object by hashing 137 * on the symbol's name. `rh_symbolnum' is the index of the symbol 138 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 139 * the next symbol in the hash bucket (in case of collisions). 140 */ 141 struct rrs_hash { 142 int rh_symbolnum; /* Symbol number */ 143 int rh_next; /* Next hash entry */ 144 }; 145 146 /* 147 * `rt_symbols' is used to keep track of run-time allocated commons 148 * and data items copied from shared objects. 149 */ 150 struct rt_symbol { 151 struct nzlist *rt_sp; /* The symbol */ 152 struct rt_symbol *rt_next; /* Next in linear list */ 153 struct rt_symbol *rt_link; /* Next in bucket */ 154 caddr_t rt_srcaddr; /* Address of "master" copy */ 155 struct so_map *rt_smp; /* Originating map */ 156 }; 157 158 /* 159 * Debugger interface structure. 160 */ 161 struct so_debug { 162 int dd_version; /* Version # of interface */ 163 int dd_in_debugger; /* Set when run by debugger */ 164 int dd_sym_loaded; /* Run-time linking brought more 165 symbols into scope */ 166 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 167 int dd_bpt_shadow; /* Original contents of bpt */ 168 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 169 }; 170 171 /* 172 * Debug rendezvous struct. Pointer to this is set up in the 173 * target code pointed by the DT_DEBUG tag. If it is 174 * defined. 175 */ 176 struct r_debug { 177 int r_version; /* Protocol version. */ 178 struct link_map *r_map; /* Head of list of loaded objects. */ 179 180 /* 181 * This is the address of a function internal to the run-time linker, 182 * that will always be called when the linker begins to map in a 183 * library or unmap it, and again when the mapping change is complete. 184 * The debugger can set a breakpoint at this address if it wants to 185 * notice shared object mapping changes. 186 */ 187 unsigned long r_brk; 188 enum { 189 /* 190 * This state value describes the mapping change taking place 191 * when the `r_brk' address is called. 192 */ 193 RT_CONSISTENT, /* Mapping change is complete. */ 194 RT_ADD, /* Adding a new object. */ 195 RT_DELETE, /* Removing an object mapping. */ 196 } r_state; 197 198 unsigned long r_ldbase; /* Base address the linker is loaded at. */ 199 }; 200 201 /* 202 * Entry points into ld.so - user interface to the run-time linker. 203 */ 204 struct ld_entry { 205 void *(*dlopen) __P((const char *, int)); 206 int (*dlclose) __P((void *)); 207 void *(*dlsym) __P((void *, const char *)); 208 int (*dlctl) __P((void *, int, void *)); 209 void (*dlexit) __P((void)); 210 void (*dlrsrvd[3]) __P((void)); 211 }; 212 213 /* 214 * This is the structure pointed at by the __DYNAMIC symbol if an 215 * executable requires the attention of the run-time link editor. 216 * __DYNAMIC is given the value zero if no run-time linking needs to 217 * be done (it is always present in shared objects). 218 * The union `d_un' provides for different versions of the dynamic 219 * linking mechanism (switched on by `d_version'). The last version 220 * used by Sun is 3. We leave some room here and go to version number 221 * 8 for NetBSD, the main difference lying in the support for the 222 * `nz_list' type of symbols. 223 */ 224 225 struct _dynamic { 226 int d_version; /* version # of this interface */ 227 struct so_debug *d_debug; 228 union { 229 struct section_dispatch_table *d_sdt; 230 } d_un; 231 struct ld_entry *d_entry; /* compat - now in crt_ldso */ 232 }; 233 234 #define LD_VERSION_SUN (3) 235 #define LD_VERSION_BSD (8) 236 #define LD_VERSION_NZLIST_P(v) ((v) >= 8) 237 238 #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 239 #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 240 #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 241 #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 242 #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 243 #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 244 #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 245 #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 246 #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths) 247 248 #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 249 #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 250 #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 251 #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 252 #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 253 #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 254 #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 255 256 /* 257 * Interface to ld.so 258 */ 259 struct crt_ldso { 260 int crt_ba; /* Base address of ld.so */ 261 int crt_dzfd; /* "/dev/zero" file decriptor (SunOS) */ 262 int crt_ldfd; /* ld.so file descriptor */ 263 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 264 char **crt_ep; /* environment strings */ 265 caddr_t crt_bp; /* Breakpoint if run from debugger */ 266 char *crt_prog; /* Program name (v3) */ 267 char *crt_ldso; /* Link editor name (v4) */ 268 struct ld_entry *crt_ldentry; /* dl*() access (v4) */ 269 }; 270 271 /* 272 * Version passed from crt0 to ld.so (1st argument to _rtld()). 273 */ 274 #define CRT_VERSION_SUN 1 275 #define CRT_VERSION_BSD_2 2 276 #define CRT_VERSION_BSD_3 3 277 #define CRT_VERSION_BSD_4 4 278 279 280 /* 281 * Maximum number of recognized shared object version numbers. 282 */ 283 #define MAXDEWEY 8 284 285 /* 286 * Header of the hints file. 287 */ 288 struct hints_header { 289 long hh_magic; 290 #define HH_MAGIC 011421044151 291 long hh_version; /* Interface version number */ 292 #define LD_HINTS_VERSION_1 1 293 #define LD_HINTS_VERSION_2 2 294 long hh_hashtab; /* Location of hash table */ 295 long hh_nbucket; /* Number of buckets in hashtab */ 296 long hh_strtab; /* Location of strings */ 297 long hh_strtab_sz; /* Size of strings */ 298 long hh_ehints; /* End of hints (max offset in file) */ 299 long hh_dirlist; /* Colon-separated list of srch dirs */ 300 }; 301 302 #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 303 304 /* 305 * Hash table element in hints file. 306 */ 307 struct hints_bucket { 308 /* namex and pathx are indices into the string table */ 309 int hi_namex; /* Library name */ 310 int hi_pathx; /* Full path */ 311 int hi_dewey[MAXDEWEY]; /* The versions */ 312 int hi_ndewey; /* Number of version numbers */ 313 #define hi_major hi_dewey[0] 314 #define hi_minor hi_dewey[1] 315 int hi_next; /* Next in this bucket */ 316 }; 317 318 #define _PATH_LD_HINTS "/var/run/ld.so.hints" 319 320 #endif /* _LINK_H_ */ 321 322