1 /* $OpenBSD: link_aout.h,v 1.2 2004/01/22 21:48:02 espie Exp $ */ 2 3 /* 4 * Copyright (c) 1993 Paul Kranenburg 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed by Paul Kranenburg. 18 * 4. The name of the author may not be used to endorse or promote products 19 * derived from this software without specific prior written permission 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 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 /* 42 * Symbol description with size. This is simply an `nlist' with 43 * one field (nz_size) added. 44 * Used to convey size information on items in the data segment 45 * of shared objects. An array of these live in the shared object's 46 * text segment and is addressed by the `sdt_nzlist' field. 47 */ 48 struct nzlist { 49 struct nlist nlist; 50 unsigned long nz_size; 51 #define nz_un nlist.n_un 52 #define nz_strx nlist.n_un.n_strx 53 #define nz_name nlist.n_un.n_name 54 #define nz_type nlist.n_type 55 #define nz_value nlist.n_value 56 #define nz_desc nlist.n_desc 57 #define nz_other nlist.n_other 58 }; 59 60 #define N_AUX(p) ((p)->n_other & 0xf) 61 #define N_BIND(p) (((unsigned int)(p)->n_other >> 4) & 0xf) 62 #define N_OTHER(r, v) (((unsigned int)(r) << 4) | ((v) & 0xf)) 63 64 #define AUX_OBJECT 1 65 #define AUX_FUNC 2 66 /*#define BIND_LOCAL 0 not used */ 67 /*#define BIND_GLOBAL 1 not used */ 68 #define BIND_WEAK 2 69 70 /* 71 * The `section_dispatch_table' structure contains offsets to various data 72 * structures needed to do run-time relocation. 73 */ 74 struct section_dispatch_table { 75 struct so_map *sdt_loaded; /* List of loaded objects */ 76 long sdt_sods; /* List of shared objects descriptors */ 77 long sdt_paths; /* Library search paths */ 78 long sdt_got; /* Global offset table */ 79 long sdt_plt; /* Procedure linkage table */ 80 long sdt_rel; /* Relocation table */ 81 long sdt_hash; /* Symbol hash table */ 82 long sdt_nzlist; /* Symbol table itself */ 83 long sdt_filler2; /* Unused (was: stab_hash) */ 84 long sdt_buckets; /* Number of hash buckets */ 85 long sdt_strings; /* Symbol strings */ 86 long sdt_str_sz; /* Size of symbol strings */ 87 long sdt_text_sz; /* Size of text area */ 88 long sdt_plt_sz; /* Size of procedure linkage table */ 89 }; 90 91 /* 92 * RRS symbol hash table, addressed by `sdt_hash' in section_dispatch_table. 93 * Used to quickly lookup symbols of the shared object by hashing 94 * on the symbol's name. `rh_symbolnum' is the index of the symbol 95 * in the shared object's symbol list (`sdt_nzlist'), `rh_next' is 96 * the next symbol in the hash bucket (in case of collisions). 97 */ 98 struct rrs_hash { 99 int rh_symbolnum; /* Symbol number */ 100 int rh_next; /* Next hash entry */ 101 }; 102 103 /* 104 * `rt_symbols' is used to keep track of run-time allocated commons 105 * and data items copied from shared objects. 106 */ 107 struct rt_symbol { 108 struct nzlist *rt_sp; /* The symbol */ 109 struct rt_symbol *rt_next; /* Next in linear list */ 110 struct rt_symbol *rt_link; /* Next in bucket */ 111 caddr_t rt_srcaddr; /* Address of "master" copy */ 112 struct so_map *rt_smp; /* Originating map */ 113 }; 114 115 /* 116 * Debugger interface structure. 117 */ 118 struct so_debug { 119 int dd_version; /* Version # of interface */ 120 int dd_in_debugger; /* Set when run by debugger */ 121 int dd_sym_loaded; /* Run-time linking brought more 122 symbols into scope */ 123 char *dd_bpt_addr; /* Address of rtld-generated bpt */ 124 int dd_bpt_shadow; /* Original contents of bpt */ 125 struct rt_symbol *dd_cc; /* Allocated commons/copied data */ 126 }; 127 128 /* 129 * Entry points into ld.so - user interface to the run-time linker. 130 */ 131 struct ld_entry { 132 void *(*dlopen)(const char *, int); 133 int (*dlclose)(void *); 134 void *(*dlsym)(void *, const char *); 135 int (*dlctl)(void *, int, void *); 136 void (*dlexit)(void); 137 void (*dlrsrvd[3])(void); 138 }; 139 140 /* 141 * This is the structure pointed at by the __DYNAMIC symbol if an 142 * executable requires the attention of the run-time link editor. 143 * __DYNAMIC is given the value zero if no run-time linking needs to 144 * be done (it is always present in shared objects). 145 * The union `d_un' provides for different versions of the dynamic 146 * linking mechanism (switched on by `d_version'). The last version 147 * used by Sun is 3. We leave some room here and go to version number 148 * 8 for NetBSD, the main difference lying in the support for the 149 * `nz_list' type of symbols. 150 */ 151 152 struct _dynamic { 153 int d_version; /* version # of this interface */ 154 struct so_debug *d_debug; 155 union { 156 struct section_dispatch_table *d_sdt; 157 } d_un; 158 struct ld_entry *d_entry; /* compat - now in crt_ldso */ 159 }; 160 161 #define LD_VERSION_SUN (3) 162 #define LD_VERSION_BSD (8) 163 #define LD_VERSION_NZLIST_P(v) ((v) >= 8) 164 165 #define LD_GOT(x) ((x)->d_un.d_sdt->sdt_got) 166 #define LD_PLT(x) ((x)->d_un.d_sdt->sdt_plt) 167 #define LD_REL(x) ((x)->d_un.d_sdt->sdt_rel) 168 #define LD_SYMBOL(x) ((x)->d_un.d_sdt->sdt_nzlist) 169 #define LD_HASH(x) ((x)->d_un.d_sdt->sdt_hash) 170 #define LD_STRINGS(x) ((x)->d_un.d_sdt->sdt_strings) 171 #define LD_NEED(x) ((x)->d_un.d_sdt->sdt_sods) 172 #define LD_BUCKETS(x) ((x)->d_un.d_sdt->sdt_buckets) 173 #define LD_PATHS(x) ((x)->d_un.d_sdt->sdt_paths) 174 175 #define LD_GOTSZ(x) ((x)->d_un.d_sdt->sdt_plt - (x)->d_un.d_sdt->sdt_got) 176 #define LD_RELSZ(x) ((x)->d_un.d_sdt->sdt_hash - (x)->d_un.d_sdt->sdt_rel) 177 #define LD_HASHSZ(x) ((x)->d_un.d_sdt->sdt_nzlist - (x)->d_un.d_sdt->sdt_hash) 178 #define LD_STABSZ(x) ((x)->d_un.d_sdt->sdt_strings - (x)->d_un.d_sdt->sdt_nzlist) 179 #define LD_PLTSZ(x) ((x)->d_un.d_sdt->sdt_plt_sz) 180 #define LD_STRSZ(x) ((x)->d_un.d_sdt->sdt_str_sz) 181 #define LD_TEXTSZ(x) ((x)->d_un.d_sdt->sdt_text_sz) 182 183 /* 184 * Interface to ld.so 185 */ 186 struct crt_ldso { 187 int crt_ba; /* Base address of ld.so */ 188 int crt_dzfd; /* "/dev/zero" file descriptor (SunOS) */ 189 int crt_ldfd; /* ld.so file descriptor */ 190 struct _dynamic *crt_dp; /* Main's __DYNAMIC */ 191 char **crt_ep; /* environment strings */ 192 caddr_t crt_bp; /* Breakpoint if run from debugger */ 193 char *crt_prog; /* Program name (v3) */ 194 char *crt_ldso; /* Link editor name (v4) */ 195 struct ld_entry *crt_ldentry; /* dl*() access (v4) */ 196 }; 197 198 /* 199 * Version passed from crt0 to ld.so (1st argument to _rtld()). 200 */ 201 #define CRT_VERSION_SUN 1 202 #define CRT_VERSION_BSD_2 2 203 #define CRT_VERSION_BSD_3 3 204 #define CRT_VERSION_BSD_4 4 205