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 1.15 1997/11/22 03:34:39 brian 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 /* 45 * A `Shared Object Descriptor' describes a shared object that is needed 46 * to complete the link edit process of the object containing it. 47 * A list of such objects (chained through `sod_next') is pointed at 48 * by `sdt_sods' in the section_dispatch_table structure. 49 */ 50 51 struct sod { /* Shared Object Descriptor */ 52 long sod_name; /* name (relative to load address) */ 53 u_int sod_library : 1, /* Searched for by library rules */ 54 sod_reserved : 31; 55 short sod_major; /* major version number */ 56 short sod_minor; /* minor version number */ 57 long sod_next; /* next sod */ 58 }; 59 60 /* 61 * `Shared Object Map's are used by the run-time link editor (ld.so) to 62 * keep track of all shared objects loaded into a process' address space. 63 * These structures are only used at run-time and do not occur within 64 * the text or data segment of an executable or shared library. 65 */ 66 struct so_map { /* Shared Object Map */ 67 caddr_t som_addr; /* Address at which object mapped */ 68 char *som_path; /* Path to mmap'ed file */ 69 struct so_map *som_next; /* Next map in chain */ 70 struct sod *som_sod; /* Sod responsible for this map */ 71 caddr_t som_sodbase; /* Base address of this sod */ 72 u_int som_write : 1; /* Text is currently writable */ 73 struct _dynamic *som_dynamic; /* _dynamic structure */ 74 caddr_t som_spd; /* Private data */ 75 }; 76 77 /* 78 * Symbol description with size. This is simply an `nlist' with 79 * one field (nz_size) added. 80 * Used to convey size information on items in the data segment 81 * of shared objects. An array of these live in the shared object's 82 * text segment and is addressed by the `sdt_nzlist' field. 83 */ 84 struct nzlist { 85 struct nlist nlist; 86 u_long nz_size; 87 #define nz_un nlist.n_un 88 #define nz_strx nlist.n_un.n_strx 89 #define nz_name nlist.n_un.n_name 90 #define nz_type nlist.n_type 91 #define nz_value nlist.n_value 92 #define nz_desc nlist.n_desc 93 #define nz_other nlist.n_other 94 }; 95 96 #define N_AUX(p) ((p)->n_other & 0xf) 97 #define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf) 98 #define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf)) 99 100 #define AUX_OBJECT 1 101 #define AUX_FUNC 2 102 /*#define BIND_LOCAL 0 not used */ 103 /*#define BIND_GLOBAL 1 not used */ 104 #define BIND_WEAK 2 105 106 107 /* 108 * The `section_dispatch_table' structure contains offsets to various data 109 * structures needed to do run-time relocation. 110 */ 111 struct section_dispatch_table { 112 struct so_map *sdt_loaded; /* List of loaded objects */ 113 long sdt_sods; /* List of shared objects descriptors */ 114 long sdt_paths; /* Library search paths */ 115 long sdt_got; /* Global offset table */ 116 long sdt_plt; /* Procedure linkage table */ 117 long sdt_rel; /* Relocation table */ 118 long sdt_hash; /* Symbol hash table */ 119 long sdt_nzlist; /* Symbol table itself */ 120 long sdt_filler2; /* Unused (was: stab_hash) */ 121 long sdt_buckets; /* Number of hash buckets */ 122 long sdt_strings; /* Symbol strings */ 123 long sdt_str_sz; /* Size of symbol strings */ 124 long sdt_text_sz; /* Size of text area */ 125 long sdt_plt_sz; /* Size of procedure linkage table */ 126 }; 127 128 /* 129 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 130 * Used to quickly lookup symbols of the shared object by hashing 131 * on the symbol's name. `rh_symbolnum' is the index of the symbol 132 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 133 * the next symbol in the hash bucket (in case of collisions). 134 */ 135 struct rrs_hash { 136 int rh_symbolnum; /* Symbol number */ 137 int rh_next; /* Next hash entry */ 138 }; 139 140 /* 141 * `rt_symbols' is used to keep track of run-time allocated commons 142 * and data items copied from shared objects. 143 */ 144 struct rt_symbol { 145 struct nzlist *rt_sp; /* The symbol */ 146 struct rt_symbol *rt_next; /* Next in linear list */ 147 struct rt_symbol *rt_link; /* Next in bucket */ 148 caddr_t rt_srcaddr; /* Address of "master" copy */ 149 struct so_map *rt_smp; /* Originating map */ 150 }; 151 152 /* 153 * Debugger interface structure. 154 */ 155 struct so_debug { 156 int dd_version; /* Version # of interface */ 157 int dd_in_debugger; /* Set when run by debugger */ 158 int dd_sym_loaded; /* Run-time linking brought more 159 symbols into scope */ 160 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 161 int dd_bpt_shadow; /* Original contents of bpt */ 162 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 163 }; 164 165 /* 166 * Version returned to crt0 from ld.so 167 */ 168 #define LDSO_VERSION_NONE 0 /* FreeBSD2.0, 2.0.5 */ 169 #define LDSO_VERSION_HAS_DLEXIT 1 /* includes dlexit in ld_entry */ 170 #define LDSO_VERSION_HAS_DLSYM3 2 /* includes 3-argument dlsym */ 171 172 /* 173 * Entry points into ld.so - user interface to the run-time linker. 174 * Entries are valid for the given version numbers returned by ld.so 175 * to crt0. 176 */ 177 struct ld_entry { 178 void *(*dlopen) __P((const char *, int)); /* NONE */ 179 int (*dlclose) __P((void *)); /* NONE */ 180 void *(*dlsym) __P((void *, const char *)); /* NONE */ 181 const char *(*dlerror) __P((void)); /* NONE */ 182 void (*dlexit) __P((void)); /* HAS_DLEXIT */ 183 void *(*dlsym3) __P((void *, const char *, void *)); /* HAS_DLSYM3 */ 184 }; 185 186 /* 187 * This is the structure pointed at by the __DYNAMIC symbol if an 188 * executable requires the attention of the run-time link editor. 189 * __DYNAMIC is given the value zero if no run-time linking needs to 190 * be done (it is always present in shared objects). 191 * The union `d_un' provides for different versions of the dynamic 192 * linking mechanism (switched on by `d_version'). The last version 193 * used by Sun is 3. We leave some room here and go to version number 194 * 8 for NetBSD, the main difference lying in the support for the 195 * `nz_list' type of symbols. 196 */ 197 198 struct _dynamic { 199 int d_version; /* version # of this interface */ 200 struct so_debug *d_debug; 201 union { 202 struct section_dispatch_table *d_sdt; 203 } d_un; 204 struct ld_entry *d_entry; /* XXX */ 205 }; 206 207 #define LD_VERSION_SUN (3) 208 #define LD_VERSION_BSD (8) 209 #define LD_VERSION_NZLIST_P(v) ((v) >= 8) 210 211 #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 212 #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 213 #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 214 #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 215 #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 216 #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 217 #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 218 #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 219 #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths) 220 221 #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 222 #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 223 #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 224 #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 225 #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 226 #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 227 #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 228 229 /* 230 * Interface to ld.so 231 */ 232 struct crt_ldso { 233 int crt_ba; /* Base address of ld.so */ 234 int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */ 235 int crt_ldfd; /* ld.so file descriptor */ 236 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 237 char **crt_ep; /* environment strings */ 238 caddr_t crt_bp; /* Breakpoint if run from debugger */ 239 char *crt_prog; /* Program name (v3) */ 240 char *crt_ldso; /* Link editor name (v4) */ 241 struct ld_entry *crt_ldentry; /* dl*() access (v4) */ 242 }; 243 244 /* 245 * Version passed from crt0 to ld.so (1st argument to _rtld()). 246 */ 247 #define CRT_VERSION_SUN 1 248 #define CRT_VERSION_BSD_2 2 249 #define CRT_VERSION_BSD_3 3 250 #define CRT_VERSION_BSD_4 4 251 252 /* 253 * Maximum number of recognized shared object version numbers. 254 */ 255 #define MAXDEWEY 8 256 257 /* 258 * Header of the hints file. 259 */ 260 struct hints_header { 261 long hh_magic; 262 #define HH_MAGIC 011421044151 263 long hh_version; /* Interface version number */ 264 #define LD_HINTS_VERSION_1 1 265 #define LD_HINTS_VERSION_2 2 266 long hh_hashtab; /* Location of hash table */ 267 long hh_nbucket; /* Number of buckets in hashtab */ 268 long hh_strtab; /* Location of strings */ 269 long hh_strtab_sz; /* Size of strings */ 270 long hh_ehints; /* End of hints (max offset in file) */ 271 long hh_dirlist; /* Colon-separated list of srch dirs */ 272 }; 273 274 #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 275 276 /* 277 * Hash table element in hints file. 278 */ 279 struct hints_bucket { 280 /* namex and pathx are indices into the string table */ 281 int hi_namex; /* Library name */ 282 int hi_pathx; /* Full path */ 283 int hi_dewey[MAXDEWEY]; /* The versions */ 284 int hi_ndewey; /* Number of version numbers */ 285 #define hi_major hi_dewey[0] 286 #define hi_minor hi_dewey[1] 287 int hi_next; /* Next in this bucket */ 288 }; 289 290 #define _PATH_LD_HINTS "/var/run/ld.so.hints" 291 292 #endif /* _LINK_H_ */ 293 294