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 1.16 1997/11/28 19:05:11 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 /* 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 }; 88 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 * The `section_dispatch_table' structure contains offsets to various data 99 * structures needed to do run-time relocation. 100 */ 101 struct section_dispatch_table { 102 struct so_map *sdt_loaded; /* List of loaded objects */ 103 long sdt_sods; /* List of shared objects descriptors */ 104 long sdt_paths; /* Library search paths */ 105 long sdt_got; /* Global offset table */ 106 long sdt_plt; /* Procedure linkage table */ 107 long sdt_rel; /* Relocation table */ 108 long sdt_hash; /* Symbol hash table */ 109 long sdt_nzlist; /* Symbol table itself */ 110 long sdt_filler2; /* Unused (was: stab_hash) */ 111 long sdt_buckets; /* Number of hash buckets */ 112 long sdt_strings; /* Symbol strings */ 113 long sdt_str_sz; /* Size of symbol strings */ 114 long sdt_text_sz; /* Size of text area */ 115 long sdt_plt_sz; /* Size of procedure linkage table */ 116 }; 117 118 /* 119 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 120 * Used to quickly lookup symbols of the shared object by hashing 121 * on the symbol's name. `rh_symbolnum' is the index of the symbol 122 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 123 * the next symbol in the hash bucket (in case of collisions). 124 */ 125 struct rrs_hash { 126 int rh_symbolnum; /* Symbol number */ 127 int rh_next; /* Next hash entry */ 128 }; 129 130 /* 131 * `rt_symbols' is used to keep track of run-time allocated commons 132 * and data items copied from shared objects. 133 */ 134 struct rt_symbol { 135 struct nzlist *rt_sp; /* The symbol */ 136 struct rt_symbol *rt_next; /* Next in linear list */ 137 struct rt_symbol *rt_link; /* Next in bucket */ 138 caddr_t rt_srcaddr; /* Address of "master" copy */ 139 struct so_map *rt_smp; /* Originating map */ 140 }; 141 142 /* 143 * Debugger interface structure. 144 */ 145 struct so_debug { 146 int dd_version; /* Version # of interface */ 147 int dd_in_debugger; /* Set when run by debugger */ 148 int dd_sym_loaded; /* Run-time linking brought more 149 symbols into scope */ 150 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 151 int dd_bpt_shadow; /* Original contents of bpt */ 152 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 153 }; 154 155 /* 156 * Version returned to crt0 from ld.so 157 */ 158 #define LDSO_VERSION_NONE 0 /* FreeBSD2.0, 2.0.5 */ 159 #define LDSO_VERSION_HAS_DLEXIT 1 /* includes dlexit in ld_entry */ 160 #define LDSO_VERSION_HAS_DLSYM3 2 /* includes 3-argument dlsym */ 161 162 /* 163 * Entry points into ld.so - user interface to the run-time linker. 164 * Entries are valid for the given version numbers returned by ld.so 165 * to crt0. 166 */ 167 struct ld_entry { 168 void *(*dlopen) __P((const char *, int)); /* NONE */ 169 int (*dlclose) __P((void *)); /* NONE */ 170 void *(*dlsym) __P((void *, const char *)); /* NONE */ 171 const char *(*dlerror) __P((void)); /* NONE */ 172 void (*dlexit) __P((void)); /* HAS_DLEXIT */ 173 void *(*dlsym3) __P((void *, const char *, void *)); /* HAS_DLSYM3 */ 174 }; 175 176 /* 177 * This is the structure pointed at by the __DYNAMIC symbol if an 178 * executable requires the attention of the run-time link editor. 179 * __DYNAMIC is given the value zero if no run-time linking needs to 180 * be done (it is always present in shared objects). 181 * The union `d_un' provides for different versions of the dynamic 182 * linking mechanism (switched on by `d_version'). The last version 183 * used by Sun is 3. We leave some room here and go to version number 184 * 8 for NetBSD, the main difference lying in the support for the 185 * `nz_list' type of symbols. 186 */ 187 188 struct _dynamic { 189 int d_version; /* version # of this interface */ 190 struct so_debug *d_debug; 191 union { 192 struct section_dispatch_table *d_sdt; 193 } d_un; 194 struct ld_entry *d_entry; /* XXX */ 195 }; 196 197 #define LD_VERSION_SUN (3) 198 #define LD_VERSION_BSD (8) 199 #define LD_VERSION_NZLIST_P(v) ((v) >= 8) 200 201 #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 202 #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 203 #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 204 #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 205 #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 206 #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 207 #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 208 #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 209 #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths) 210 211 #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 212 #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 213 #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 214 #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 215 #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 216 #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 217 #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 218 219 /* 220 * Interface to ld.so 221 */ 222 struct crt_ldso { 223 int crt_ba; /* Base address of ld.so */ 224 int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */ 225 int crt_ldfd; /* ld.so file descriptor */ 226 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 227 char **crt_ep; /* environment strings */ 228 caddr_t crt_bp; /* Breakpoint if run from debugger */ 229 char *crt_prog; /* Program name (v3) */ 230 char *crt_ldso; /* Link editor name (v4) */ 231 struct ld_entry *crt_ldentry; /* dl*() access (v4) */ 232 }; 233 234 /* 235 * Version passed from crt0 to ld.so (1st argument to _rtld()). 236 */ 237 #define CRT_VERSION_SUN 1 238 #define CRT_VERSION_BSD_2 2 239 #define CRT_VERSION_BSD_3 3 240 #define CRT_VERSION_BSD_4 4 241 242 /* 243 * Maximum number of recognized shared object version numbers. 244 */ 245 #define MAXDEWEY 8 246 247 /* 248 * Header of the hints file. 249 */ 250 struct hints_header { 251 long hh_magic; 252 #define HH_MAGIC 011421044151 253 long hh_version; /* Interface version number */ 254 #define LD_HINTS_VERSION_1 1 255 #define LD_HINTS_VERSION_2 2 256 long hh_hashtab; /* Location of hash table */ 257 long hh_nbucket; /* Number of buckets in hashtab */ 258 long hh_strtab; /* Location of strings */ 259 long hh_strtab_sz; /* Size of strings */ 260 long hh_ehints; /* End of hints (max offset in file) */ 261 long hh_dirlist; /* Colon-separated list of srch dirs */ 262 }; 263 264 #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 265 266 /* 267 * Hash table element in hints file. 268 */ 269 struct hints_bucket { 270 /* namex and pathx are indices into the string table */ 271 int hi_namex; /* Library name */ 272 int hi_pathx; /* Full path */ 273 int hi_dewey[MAXDEWEY]; /* The versions */ 274 int hi_ndewey; /* Number of version numbers */ 275 #define hi_major hi_dewey[0] 276 #define hi_minor hi_dewey[1] 277 int hi_next; /* Next in this bucket */ 278 }; 279 280 #define _PATH_LD_HINTS "/var/run/ld.so.hints" 281 282 #endif /* _LINK_H_ */ 283