1 /* 2 * RRS section definitions. 3 * Nomenclature and, more importantly, the layout of the various 4 * data structures defined in this header file are borrowed from 5 * Sun Microsystems' original <link.h>, so we can provide compatibility 6 * with the SunOS 4.x shared library scheme. 7 * 8 * $Id: link_aout.h,v 1.2 1993/10/22 21:04:19 pk Exp $ 9 * (derived from: @(#)link.h 1.6 88/08/19 SMI 10 * Copyright (c) 1987 by Sun Microsystems, Inc.) 11 */ 12 13 #ifndef _LINK_H_ 14 #define _LINK_H_ 15 16 /* 17 * A `link_object' structure descibes a shared object that is needed 18 * to complete the link edit process of the object containing it. 19 * A list of such objects (chained through `lo_next') is pointed at 20 * by `ld_need' in the link_dynamic_2 structure. 21 */ 22 23 struct link_object { 24 long lo_name; /* name (relative to load address) */ 25 u_int lo_library : 1, /* searched for by library rules */ 26 lo_unused : 31; 27 short lo_major; /* major version number */ 28 short lo_minor; /* minor version number */ 29 long lo_next; /* next one (often relative) */ 30 }; 31 32 /* 33 * `link_maps' are used by the run-time link editor (ld.so) to keep 34 * track of all shared objects loaded into a process' address space. 35 * These structures are only used at run-time and do not occur within 36 * the text or data segment of an executable or shared library. 37 */ 38 struct link_map { 39 caddr_t lm_addr; /* address at which object mapped */ 40 char *lm_name; /* full name of loaded object */ 41 struct link_map *lm_next; /* next object in map */ 42 struct link_object *lm_lop; /* link object that got us here */ 43 caddr_t lm_lob; /* base address for said link object */ 44 u_int lm_rwt : 1; /* text is read/write */ 45 struct link_dynamic *lm_ld; /* dynamic structure */ 46 caddr_t lm_lpd; /* loader private data */ 47 }; 48 49 /* 50 * Symbol description with size. This is simply an `nlist' with 51 * one field (nz_size) added. 52 * Used to convey size information on items in the data segment 53 * of shared objects. An array of these live in the shared object's 54 * text segment and is address by the `ld_symbols' field. 55 */ 56 struct nzlist { 57 struct nlist nlist; 58 u_long nz_size; 59 #define nz_un nlist.n_un 60 #define nz_strx nlist.n_un.n_strx 61 #define nz_name nlist.n_un.n_name 62 #define nz_type nlist.n_type 63 #define nz_value nlist.n_value 64 #define nz_desc nlist.n_desc 65 #define nz_other nlist.n_other 66 }; 67 68 /* 69 * The `link_dynamic_2' structure contains offsets to various data 70 * structures needed to do run-time relocation. 71 */ 72 struct link_dynamic_2 { 73 struct link_map *ld_loaded; /* list of loaded objects */ 74 long ld_need; /* list of needed objects */ 75 long ld_rules; /* search rules for library objects */ 76 long ld_got; /* global offset table */ 77 long ld_plt; /* procedure linkage table */ 78 long ld_rel; /* relocation table */ 79 long ld_hash; /* symbol hash table */ 80 long ld_symbols; /* symbol table itself */ 81 long (*ld_stab_hash)(); /* "pointer" to symbol hash function */ 82 long ld_buckets; /* number of hash buckets */ 83 long ld_strings; /* symbol strings */ 84 long ld_str_sz; /* size of symbol strings */ 85 long ld_text_sz; /* size of text area */ 86 long ld_plt_sz; /* size of procedure linkage table */ 87 }; 88 89 /* 90 * RRS symbol hash table, addressed by `ld_hash' in link_dynamic_2 91 * Used to quickly lookup symbols of the shared object by hashing 92 * on the symbol's name. `rh_symbolnum' is the index of the symbol 93 * in the shared object's symbol list (`ld_symbols'), `rh_next' is 94 * the next symbol in the hash bucket (in case of collisions). 95 */ 96 struct rrs_hash { 97 int rh_symbolnum; /* symbol number */ 98 int rh_next; /* next hash entry */ 99 }; 100 101 /* 102 * `rt_symbols' is used to keep track of run-time allocated commons 103 * and data items copied from shared objects. 104 */ 105 struct rt_symbol { 106 struct nzlist *rt_sp; /* the symbol */ 107 struct rt_symbol *rt_next; /* next in linear list */ 108 struct rt_symbol *rt_link; /* next in bucket */ 109 caddr_t rt_srcaddr; /* address of "master" copy */ 110 }; 111 112 /* 113 * Debugger interface structure. 114 */ 115 struct ld_debug { 116 int ldd_version; /* version # of interface */ 117 int ldd_in_debugger; /* a debugger is running us */ 118 int ldd_sym_loaded; /* we loaded some symbols */ 119 char *ldd_bp_addr; /* place for ld-generated bpt */ 120 int ldd_bp_inst; /* instruction which was there */ 121 struct rt_symbol *ldd_cp; /* commons we built */ 122 }; 123 124 /* 125 * Entry points into ld.so - user interface to the run-time linker. 126 * (see also libdl.a) 127 */ 128 struct ld_entry { 129 int (*dlopen)(); 130 int (*dlclose)(); 131 int (*dlsym)(); 132 }; 133 134 /* 135 * This is the structure pointed at by the __DYNAMIC symbol if an 136 * executable requires the attention of the run-time link editor. 137 * __DYNAMIC is given the value zero if no run-time linking needs to 138 * be done (it is always present in shared objects). 139 * The union `ld_un' provides for different versions of the dynamic 140 * linking mechanism (switched on by `ld_version'). The last version 141 * used by Sun is 3. We leave some room here and go to version number 142 * 8 for NetBSD, the main difference lying in the support for the 143 * `nz_list' type of symbols. 144 */ 145 146 struct link_dynamic { 147 int ld_version; /* version # of this structure */ 148 struct ld_debug *ldd; 149 union { 150 struct link_dynamic_2 *ld_2; 151 } ld_un; 152 struct ld_entry *ld_entry; 153 }; 154 155 #define LD_VERSION_SUN (3) 156 #define LD_VERSION_BSD (8) 157 #define LD_VERSION_NZLIST_P(v) ((v) >= 8) 158 159 #define LD_GOT(x) ((x)->ld_un.ld_2->ld_got) 160 #define LD_PLT(x) ((x)->ld_un.ld_2->ld_plt) 161 #define LD_REL(x) ((x)->ld_un.ld_2->ld_rel) 162 #define LD_SYMBOL(x) ((x)->ld_un.ld_2->ld_symbols) 163 #define LD_HASH(x) ((x)->ld_un.ld_2->ld_hash) 164 #define LD_STRINGS(x) ((x)->ld_un.ld_2->ld_strings) 165 #define LD_NEED(x) ((x)->ld_un.ld_2->ld_need) 166 #define LD_BUCKETS(x) ((x)->ld_un.ld_2->ld_buckets) 167 168 #define LD_GOTSZ(x) ((x)->ld_un.ld_2->ld_plt - (x)->ld_un.ld_2->ld_got) 169 #define LD_RELSZ(x) ((x)->ld_un.ld_2->ld_hash - (x)->ld_un.ld_2->ld_rel) 170 #define LD_HASHSZ(x) ((x)->ld_un.ld_2->ld_symbols - (x)->ld_un.ld_2->ld_hash) 171 #define LD_STABSZ(x) ((x)->ld_un.ld_2->ld_strings - (x)->ld_un.ld_2->ld_symbols) 172 #define LD_PLTSZ(x) ((x)->ld_un.ld_2->ld_plt_sz) 173 #define LD_STRSZ(x) ((x)->ld_un.ld_2->ld_str_sz) 174 #define LD_TEXTSZ(x) ((x)->ld_un.ld_2->ld_text_sz) 175 176 /* 177 * Interface to ld.so (see link(5)) 178 */ 179 struct crt_ldso { 180 int crt_ba; /* Base address of ld.so */ 181 int crt_dzfd; /* "/dev/zero" file decriptor (SunOS) */ 182 int crt_ldfd; /* ld.so file descriptor */ 183 struct link_dynamic *crt_dp;/* Main's __DYNAMIC */ 184 char **crt_ep; /* environment strings */ 185 caddr_t crt_bp; /* Breakpoint if run from debugger */ 186 }; 187 188 /* 189 * Version passed from crt0 to ld.so (1st argument to _rtld()). 190 */ 191 #define CRT_VERSION_SUN 1 192 #define CRT_VERSION_BSD 2 193 194 195 /* 196 * Maximum number of recognized shared object version numbers. 197 */ 198 #define MAXDEWEY 8 199 200 /* 201 * Header of the hints file. 202 */ 203 struct hints_header { 204 long hh_magic; 205 #define HH_MAGIC 011421044151 206 long hh_version; /* Interface version number */ 207 #define LD_HINTS_VERSION_1 1 208 long hh_hashtab; /* Location of hash table */ 209 long hh_nbucket; /* Number of buckets in hashtab */ 210 long hh_strtab; /* Location of strings */ 211 long hh_strtab_sz; /* Size of strings */ 212 long hh_ehints; /* End of hints (max offset in file) */ 213 }; 214 215 #define HH_BADMAG(hdr) ((hdr).hh_magic != HH_MAGIC) 216 217 /* 218 * Hash table element in hints file. 219 */ 220 struct hints_bucket { 221 /* namex and pathx are indices into the string table */ 222 int hi_namex; /* Library name */ 223 int hi_pathx; /* Full path */ 224 int hi_dewey[MAXDEWEY]; /* The versions */ 225 int hi_ndewey; /* Number of version numbers */ 226 #define hi_major hi_dewey[0] 227 #define hi_minor hi_dewey[1] 228 int hi_next; /* Next in this bucket */ 229 }; 230 231 #define _PATH_LD_HINTS "/var/run/ld.so.hints" 232 233 #endif /* _LINK_H_ */ 234 235