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 * $Id: link.h,v 1.18 1998/02/06 16:46:44 jdp Exp $ 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 #if (defined(FREEBSD_ELF) || defined(__ELF__)) && !defined(FREEBSD_AOUT) 45 46 #include <sys/types.h> 47 48 struct link_map { 49 caddr_t l_addr; /* Base Address of library */ 50 #ifdef __mips__ 51 caddr_t l_offs; /* Load Offset of library */ 52 #endif 53 const char *l_name; /* Absolute Path to Library */ 54 const void *l_ld; /* Pointer to .dynamic in memory */ 55 struct link_map *l_next, *l_prev; /* linked list of of mapped libs */ 56 }; 57 58 struct r_debug { 59 int r_version; /* not used */ 60 struct link_map *r_map; /* list of loaded images */ 61 void (*r_brk)(void); /* pointer to break point */ 62 enum { 63 RT_CONSISTENT, /* things are stable */ 64 RT_ADD, /* adding a shared library */ 65 RT_DELETE /* removing a shared library */ 66 } r_state; 67 }; 68 69 #else /* !__ELF__ */ 70 71 struct dl_info; 72 73 /* 74 * A `Shared Object Descriptor' describes a shared object that is needed 75 * to complete the link edit process of the object containing it. 76 * A list of such objects (chained through `sod_next') is pointed at 77 * by `sdt_sods' in the section_dispatch_table structure. 78 */ 79 80 struct sod { /* Shared Object Descriptor */ 81 long sod_name; /* name (relative to load address) */ 82 u_int sod_library : 1, /* Searched for by library rules */ 83 sod_reserved : 31; 84 short sod_major; /* major version number */ 85 short sod_minor; /* minor version number */ 86 long sod_next; /* next sod */ 87 }; 88 89 /* 90 * `Shared Object Map's are used by the run-time link editor (ld.so) to 91 * keep track of all shared objects loaded into a process' address space. 92 * These structures are only used at run-time and do not occur within 93 * the text or data segment of an executable or shared library. 94 */ 95 struct so_map { /* Shared Object Map */ 96 caddr_t som_addr; /* Address at which object mapped */ 97 char *som_path; /* Path to mmap'ed file */ 98 struct so_map *som_next; /* Next map in chain */ 99 struct sod *som_sod; /* Sod responsible for this map */ 100 caddr_t som_sodbase; /* Base address of this sod */ 101 u_int som_write : 1; /* Text is currently writable */ 102 struct _dynamic *som_dynamic; /* _dynamic structure */ 103 caddr_t som_spd; /* Private data */ 104 }; 105 106 /* 107 * Symbol description with size. This is simply an `nlist' with 108 * one field (nz_size) added. 109 * Used to convey size information on items in the data segment 110 * of shared objects. An array of these live in the shared object's 111 * text segment and is addressed by the `sdt_nzlist' field. 112 */ 113 struct nzlist { 114 struct nlist nlist; 115 u_long nz_size; 116 }; 117 118 #define nz_un nlist.n_un 119 #define nz_strx nlist.n_un.n_strx 120 #define nz_name nlist.n_un.n_name 121 #define nz_type nlist.n_type 122 #define nz_value nlist.n_value 123 #define nz_desc nlist.n_desc 124 #define nz_other nlist.n_other 125 126 /* 127 * The `section_dispatch_table' structure contains offsets to various data 128 * structures needed to do run-time relocation. 129 */ 130 struct section_dispatch_table { 131 struct so_map *sdt_loaded; /* List of loaded objects */ 132 long sdt_sods; /* List of shared objects descriptors */ 133 long sdt_paths; /* Library search paths */ 134 long sdt_got; /* Global offset table */ 135 long sdt_plt; /* Procedure linkage table */ 136 long sdt_rel; /* Relocation table */ 137 long sdt_hash; /* Symbol hash table */ 138 long sdt_nzlist; /* Symbol table itself */ 139 long sdt_filler2; /* Unused (was: stab_hash) */ 140 long sdt_buckets; /* Number of hash buckets */ 141 long sdt_strings; /* Symbol strings */ 142 long sdt_str_sz; /* Size of symbol strings */ 143 long sdt_text_sz; /* Size of text area */ 144 long sdt_plt_sz; /* Size of procedure linkage table */ 145 }; 146 147 /* 148 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 149 * Used to quickly lookup symbols of the shared object by hashing 150 * on the symbol's name. `rh_symbolnum' is the index of the symbol 151 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 152 * the next symbol in the hash bucket (in case of collisions). 153 */ 154 struct rrs_hash { 155 int rh_symbolnum; /* Symbol number */ 156 int rh_next; /* Next hash entry */ 157 }; 158 159 /* 160 * `rt_symbols' is used to keep track of run-time allocated commons 161 * and data items copied from shared objects. 162 */ 163 struct rt_symbol { 164 struct nzlist *rt_sp; /* The symbol */ 165 struct rt_symbol *rt_next; /* Next in linear list */ 166 struct rt_symbol *rt_link; /* Next in bucket */ 167 caddr_t rt_srcaddr; /* Address of "master" copy */ 168 struct so_map *rt_smp; /* Originating map */ 169 }; 170 171 /* 172 * Debugger interface structure. 173 */ 174 struct so_debug { 175 int dd_version; /* Version # of interface */ 176 int dd_in_debugger; /* Set when run by debugger */ 177 int dd_sym_loaded; /* Run-time linking brought more 178 symbols into scope */ 179 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 180 int dd_bpt_shadow; /* Original contents of bpt */ 181 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 182 }; 183 184 /* 185 * Version returned to crt0 from ld.so 186 */ 187 #define LDSO_VERSION_NONE 0 /* FreeBSD2.0, 2.0.5 */ 188 #define LDSO_VERSION_HAS_DLEXIT 1 /* includes dlexit in ld_entry */ 189 #define LDSO_VERSION_HAS_DLSYM3 2 /* includes 3-argument dlsym */ 190 #define LDSO_VERSION_HAS_DLADDR 3 /* includes dladdr in ld_entry */ 191 192 /* 193 * Entry points into ld.so - user interface to the run-time linker. 194 * Entries are valid for the given version numbers returned by ld.so 195 * to crt0. 196 */ 197 struct ld_entry { 198 void *(*dlopen) __P((const char *, int)); /* NONE */ 199 int (*dlclose) __P((void *)); /* NONE */ 200 void *(*dlsym) __P((void *, const char *)); /* NONE */ 201 const char *(*dlerror) __P((void)); /* NONE */ 202 void (*dlexit) __P((void)); /* HAS_DLEXIT */ 203 void *(*dlsym3) __P((void *, const char *, void *)); /* HAS_DLSYM3 */ 204 int (*dladdr) __P((const void *, 205 struct dl_info *)); /* HAS_DLADDR */ 206 }; 207 208 /* 209 * This is the structure pointed at by the __DYNAMIC symbol if an 210 * executable requires the attention of the run-time link editor. 211 * __DYNAMIC is given the value zero if no run-time linking needs to 212 * be done (it is always present in shared objects). 213 * The union `d_un' provides for different versions of the dynamic 214 * linking mechanism (switched on by `d_version'). The last version 215 * used by Sun is 3. We leave some room here and go to version number 216 * 8 for NetBSD, the main difference lying in the support for the 217 * `nz_list' type of symbols. 218 */ 219 220 struct _dynamic { 221 int d_version; /* version # of this interface */ 222 struct so_debug *d_debug; 223 union { 224 struct section_dispatch_table *d_sdt; 225 } d_un; 226 struct ld_entry *d_entry; /* XXX */ 227 }; 228 229 #define LD_VERSION_SUN (3) 230 #define LD_VERSION_BSD (8) 231 #define LD_VERSION_NZLIST_P(v) ((v) >= 8) 232 233 #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 234 #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 235 #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 236 #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 237 #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 238 #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 239 #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 240 #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 241 #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths) 242 243 #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 244 #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 245 #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 246 #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 247 #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 248 #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 249 #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 250 251 /* 252 * Interface to ld.so 253 */ 254 struct crt_ldso { 255 int crt_ba; /* Base address of ld.so */ 256 int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */ 257 int crt_ldfd; /* ld.so file descriptor */ 258 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 259 char **crt_ep; /* environment strings */ 260 caddr_t crt_bp; /* Breakpoint if run from debugger */ 261 char *crt_prog; /* Program name (v3) */ 262 char *crt_ldso; /* Link editor name (v4) */ 263 struct ld_entry *crt_ldentry; /* dl*() access (v4) */ 264 char **crt_argv; /* argument strings (v5) */ 265 }; 266 267 /* 268 * Version passed from crt0 to ld.so (1st argument to _rtld()). 269 */ 270 #define CRT_VERSION_SUN 1 271 #define CRT_VERSION_BSD_2 2 272 #define CRT_VERSION_BSD_3 3 273 #define CRT_VERSION_BSD_4 4 274 #define CRT_VERSION_BSD_5 5 275 276 /* 277 * Maximum number of recognized shared object version numbers. 278 */ 279 #define MAXDEWEY 8 280 281 /* 282 * Header of the hints file. 283 */ 284 struct hints_header { 285 long hh_magic; 286 #define HH_MAGIC 011421044151 287 long hh_version; /* Interface version number */ 288 #define LD_HINTS_VERSION_1 1 289 #define LD_HINTS_VERSION_2 2 290 long hh_hashtab; /* Location of hash table */ 291 long hh_nbucket; /* Number of buckets in hashtab */ 292 long hh_strtab; /* Location of strings */ 293 long hh_strtab_sz; /* Size of strings */ 294 long hh_ehints; /* End of hints (max offset in file) */ 295 long hh_dirlist; /* Colon-separated list of srch dirs */ 296 }; 297 298 #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 299 300 /* 301 * Hash table element in hints file. 302 */ 303 struct hints_bucket { 304 /* namex and pathx are indices into the string table */ 305 int hi_namex; /* Library name */ 306 int hi_pathx; /* Full path */ 307 int hi_dewey[MAXDEWEY]; /* The versions */ 308 int hi_ndewey; /* Number of version numbers */ 309 #define hi_major hi_dewey[0] 310 #define hi_minor hi_dewey[1] 311 int hi_next; /* Next in this bucket */ 312 }; 313 314 #define _PATH_LD_HINTS "/var/run/ld.so.hints" 315 316 #endif /* !__ELF__ */ 317 318 #endif /* _LINK_H_ */ 319