1 /* 2 * Copyright (c) 1993 Paul Kranenburg 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by Paul Kranenburg. 16 * 4. The name of the author may not be used to endorse or promote products 17 * derived from this software without specific prior written permission 18 * 19 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 20 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 21 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 22 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 23 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 24 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 28 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 * 30 * $FreeBSD: src/sys/sys/link_elf.h,v 1.20.2.2 2003/02/20 20:42:46 kan Exp $ 31 * $DragonFly: src/sys/sys/link_elf.h,v 1.3 2003/08/20 07:31:21 rob Exp $ 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 #if (defined(FREEBSD_ELF) || defined(__ELF__)) && !defined(FREEBSD_AOUT) 46 47 #include <sys/types.h> 48 49 /* 50 * Flags that describe the origin of the entries in Dl_serinfo. 51 * SunOS has these in <sys/link.h>, we follow the suit. 52 */ 53 #define LA_SER_ORIG 0x01 /* original (needed) name */ 54 #define LA_SER_LIBPATH 0x02 /* LD_LIBRARY_PATH entry prepended */ 55 #define LA_SER_RUNPATH 0x04 /* runpath entry prepended */ 56 #define LA_SER_CONFIG 0x08 /* configuration entry prepended */ 57 #define LA_SER_DEFAULT 0x40 /* default path prepended */ 58 #define LA_SER_SECURE 0x80 /* default (secure) path prepended */ 59 60 typedef struct link_map { 61 caddr_t l_addr; /* Base Address of library */ 62 #ifdef __mips__ 63 caddr_t l_offs; /* Load Offset of library */ 64 #endif 65 const char *l_name; /* Absolute Path to Library */ 66 const void *l_ld; /* Pointer to .dynamic in memory */ 67 struct link_map *l_next, *l_prev; /* linked list of of mapped libs */ 68 } Link_map; 69 70 struct r_debug { 71 int r_version; /* not used */ 72 struct link_map *r_map; /* list of loaded images */ 73 void (*r_brk)(struct r_debug *, struct link_map *); 74 /* pointer to break point */ 75 enum { 76 RT_CONSISTENT, /* things are stable */ 77 RT_ADD, /* adding a shared library */ 78 RT_DELETE /* removing a shared library */ 79 } r_state; 80 }; 81 82 #else /* !__ELF__ */ 83 84 struct dl_info; 85 86 /* 87 * A `Shared Object Descriptor' describes a shared object that is needed 88 * to complete the link edit process of the object containing it. 89 * A list of such objects (chained through `sod_next') is pointed at 90 * by `sdt_sods' in the section_dispatch_table structure. 91 */ 92 93 struct sod { /* Shared Object Descriptor */ 94 long sod_name; /* name (relative to load address) */ 95 u_int sod_library : 1, /* Searched for by library rules */ 96 sod_reserved : 31; 97 short sod_major; /* major version number */ 98 short sod_minor; /* minor version number */ 99 long sod_next; /* next sod */ 100 }; 101 102 /* 103 * `Shared Object Map's are used by the run-time link editor (ld.so) to 104 * keep track of all shared objects loaded into a process' address space. 105 * These structures are only used at run-time and do not occur within 106 * the text or data segment of an executable or shared library. 107 */ 108 struct so_map { /* Shared Object Map */ 109 caddr_t som_addr; /* Address at which object mapped */ 110 char *som_path; /* Path to mmap'ed file */ 111 struct so_map *som_next; /* Next map in chain */ 112 struct sod *som_sod; /* Sod responsible for this map */ 113 caddr_t som_sodbase; /* Base address of this sod */ 114 u_int som_write : 1; /* Text is currently writable */ 115 struct _dynamic *som_dynamic; /* _dynamic structure */ 116 caddr_t som_spd; /* Private data */ 117 }; 118 119 /* 120 * Symbol description with size. This is simply an `nlist' with 121 * one field (nz_size) added. 122 * Used to convey size information on items in the data segment 123 * of shared objects. An array of these live in the shared object's 124 * text segment and is addressed by the `sdt_nzlist' field. 125 */ 126 struct nzlist { 127 struct nlist nlist; 128 u_long nz_size; 129 }; 130 131 #define nz_un nlist.n_un 132 #define nz_strx nlist.n_un.n_strx 133 #define nz_name nlist.n_un.n_name 134 #define nz_type nlist.n_type 135 #define nz_value nlist.n_value 136 #define nz_desc nlist.n_desc 137 #define nz_other nlist.n_other 138 139 /* 140 * The `section_dispatch_table' structure contains offsets to various data 141 * structures needed to do run-time relocation. 142 */ 143 struct section_dispatch_table { 144 struct so_map *sdt_loaded; /* List of loaded objects */ 145 long sdt_sods; /* List of shared objects descriptors */ 146 long sdt_paths; /* Library search paths */ 147 long sdt_got; /* Global offset table */ 148 long sdt_plt; /* Procedure linkage table */ 149 long sdt_rel; /* Relocation table */ 150 long sdt_hash; /* Symbol hash table */ 151 long sdt_nzlist; /* Symbol table itself */ 152 long sdt_filler2; /* Unused (was: stab_hash) */ 153 long sdt_buckets; /* Number of hash buckets */ 154 long sdt_strings; /* Symbol strings */ 155 long sdt_str_sz; /* Size of symbol strings */ 156 long sdt_text_sz; /* Size of text area */ 157 long sdt_plt_sz; /* Size of procedure linkage table */ 158 }; 159 160 /* 161 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 162 * Used to quickly lookup symbols of the shared object by hashing 163 * on the symbol's name. `rh_symbolnum' is the index of the symbol 164 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 165 * the next symbol in the hash bucket (in case of collisions). 166 */ 167 struct rrs_hash { 168 int rh_symbolnum; /* Symbol number */ 169 int rh_next; /* Next hash entry */ 170 }; 171 172 /* 173 * `rt_symbols' is used to keep track of run-time allocated commons 174 * and data items copied from shared objects. 175 */ 176 struct rt_symbol { 177 struct nzlist *rt_sp; /* The symbol */ 178 struct rt_symbol *rt_next; /* Next in linear list */ 179 struct rt_symbol *rt_link; /* Next in bucket */ 180 caddr_t rt_srcaddr; /* Address of "master" copy */ 181 struct so_map *rt_smp; /* Originating map */ 182 }; 183 184 /* 185 * Debugger interface structure. 186 */ 187 struct so_debug { 188 int dd_version; /* Version # of interface */ 189 int dd_in_debugger; /* Set when run by debugger */ 190 int dd_sym_loaded; /* Run-time linking brought more 191 symbols into scope */ 192 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 193 int dd_bpt_shadow; /* Original contents of bpt */ 194 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 195 }; 196 197 /* 198 * Version returned to crt0 from ld.so 199 */ 200 #define LDSO_VERSION_NONE 0 /* FreeBSD2.0, 2.0.5 */ 201 #define LDSO_VERSION_HAS_DLEXIT 1 /* includes dlexit in ld_entry */ 202 #define LDSO_VERSION_HAS_DLSYM3 2 /* includes 3-argument dlsym */ 203 #define LDSO_VERSION_HAS_DLADDR 3 /* includes dladdr in ld_entry */ 204 205 /* 206 * Entry points into ld.so - user interface to the run-time linker. 207 * Entries are valid for the given version numbers returned by ld.so 208 * to crt0. 209 */ 210 struct ld_entry { 211 void *(*dlopen) (const char *, int); /* NONE */ 212 int (*dlclose) (void *); /* NONE */ 213 void *(*dlsym) (void *, const char *); /* NONE */ 214 const char *(*dlerror) (void); /* NONE */ 215 void (*dlexit) (void); /* HAS_DLEXIT */ 216 void *(*dlsym3) (void *, const char *, void *); /* HAS_DLSYM3 */ 217 int (*dladdr) (const void *, 218 struct dl_info *); /* HAS_DLADDR */ 219 }; 220 221 /* 222 * This is the structure pointed at by the __DYNAMIC symbol if an 223 * executable requires the attention of the run-time link editor. 224 * __DYNAMIC is given the value zero if no run-time linking needs to 225 * be done (it is always present in shared objects). 226 * The union `d_un' provides for different versions of the dynamic 227 * linking mechanism (switched on by `d_version'). The last version 228 * used by Sun is 3. We leave some room here and go to version number 229 * 8 for NetBSD, the main difference lying in the support for the 230 * `nz_list' type of symbols. 231 */ 232 233 struct _dynamic { 234 int d_version; /* version # of this interface */ 235 struct so_debug *d_debug; 236 union { 237 struct section_dispatch_table *d_sdt; 238 } d_un; 239 struct ld_entry *d_entry; /* XXX */ 240 }; 241 242 #define LD_VERSION_SUN (3) 243 #define LD_VERSION_BSD (8) 244 #define LD_VERSION_NZLIST_P(v) ((v) >= 8) 245 246 #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 247 #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 248 #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 249 #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 250 #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 251 #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 252 #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 253 #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 254 #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths) 255 256 #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 257 #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 258 #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 259 #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 260 #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 261 #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 262 #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 263 264 /* 265 * Interface to ld.so 266 */ 267 struct crt_ldso { 268 int crt_ba; /* Base address of ld.so */ 269 int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */ 270 int crt_ldfd; /* ld.so file descriptor */ 271 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 272 char **crt_ep; /* environment strings */ 273 caddr_t crt_bp; /* Breakpoint if run from debugger */ 274 char *crt_prog; /* Program name (v3) */ 275 char *crt_ldso; /* Link editor name (v4) */ 276 struct ld_entry *crt_ldentry; /* dl*() access (v4) */ 277 char **crt_argv; /* argument strings (v5) */ 278 }; 279 280 /* 281 * Version passed from crt0 to ld.so (1st argument to _rtld()). 282 */ 283 #define CRT_VERSION_SUN 1 284 #define CRT_VERSION_BSD_2 2 285 #define CRT_VERSION_BSD_3 3 286 #define CRT_VERSION_BSD_4 4 287 #define CRT_VERSION_BSD_5 5 288 289 /* 290 * Maximum number of recognized shared object version numbers. 291 */ 292 #define MAXDEWEY 8 293 294 /* 295 * Header of the hints file. 296 */ 297 struct hints_header { 298 long hh_magic; 299 #define HH_MAGIC 011421044151 300 long hh_version; /* Interface version number */ 301 #define LD_HINTS_VERSION_1 1 302 #define LD_HINTS_VERSION_2 2 303 long hh_hashtab; /* Location of hash table */ 304 long hh_nbucket; /* Number of buckets in hashtab */ 305 long hh_strtab; /* Location of strings */ 306 long hh_strtab_sz; /* Size of strings */ 307 long hh_ehints; /* End of hints (max offset in file) */ 308 long hh_dirlist; /* Colon-separated list of srch dirs */ 309 }; 310 311 #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 312 313 /* 314 * Hash table element in hints file. 315 */ 316 struct hints_bucket { 317 /* namex and pathx are indices into the string table */ 318 int hi_namex; /* Library name */ 319 int hi_pathx; /* Full path */ 320 int hi_dewey[MAXDEWEY]; /* The versions */ 321 int hi_ndewey; /* Number of version numbers */ 322 #define hi_major hi_dewey[0] 323 #define hi_minor hi_dewey[1] 324 int hi_next; /* Next in this bucket */ 325 }; 326 327 #define _PATH_LD_HINTS "/var/run/ld.so.hints" 328 329 #endif /* !__ELF__ */ 330 331 #endif /* _LINK_H_ */ 332