1 /* $OpenBSD: resolve.h,v 1.91 2019/05/10 13:29:21 guenther Exp $ */ 2 3 /* 4 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS 16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY 19 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 * 27 */ 28 29 #ifndef _RESOLVE_H_ 30 #define _RESOLVE_H_ 31 32 #include <sys/queue.h> 33 #include <dlfcn.h> 34 #include <link.h> 35 #include <tib.h> 36 37 #define __relro __attribute__((section(".data.rel.ro"))) 38 39 #ifndef __boot 40 # if DO_CLEAN_BOOT 41 # define __boot __attribute__((section(".boot.text"))) 42 # define __boot_data __attribute__((section(".boot.data"))) 43 # else 44 # define __boot 45 # define __boot_data 46 # endif 47 #endif 48 49 /* Number of low tags that are used saved internally (0 .. DT_NUM-1) */ 50 #define DT_NUM (DT_PREINIT_ARRAYSZ + 1) 51 52 struct load_list { 53 struct load_list *next; 54 void *start; 55 size_t size; 56 int prot; 57 Elf_Addr moff; 58 long foff; 59 }; 60 61 typedef void initarrayfunc(int, const char **, char **, dl_cb_cb *); 62 typedef void initfunc(void); /* also fini and fini_array functions */ 63 64 /* Alpha uses 8byte entries for DT_HASH */ 65 #ifdef __alpha__ 66 typedef uint64_t Elf_Hash_Word; 67 #else 68 typedef uint32_t Elf_Hash_Word; 69 #endif 70 71 /* 72 * Structure describing a loaded object. 73 * The head of this struct must be compatible 74 * with struct link_map in sys/link.h 75 */ 76 typedef struct elf_object elf_object_t; 77 struct elf_object { 78 Elf_Addr obj_base; /* object's address '0' base */ 79 char *load_name; /* Pointer to object name */ 80 Elf_Dyn *load_dyn; /* Pointer to object dynamic data */ 81 struct elf_object *next; 82 struct elf_object *prev; 83 /* End struct link_map compatible */ 84 Elf_Addr load_base; /* Base address of loadable segments */ 85 86 struct load_list *load_list; 87 88 u_int32_t load_size; 89 90 union { 91 u_long info[DT_NUM + DT_PROCNUM]; 92 struct { 93 Elf_Addr null; /* Not used */ 94 Elf_Addr needed; /* Not used */ 95 Elf_Addr pltrelsz; 96 Elf_Addr *pltgot; 97 Elf_Addr *hash; 98 const char *strtab; 99 const Elf_Sym *symtab; 100 Elf_RelA *rela; 101 Elf_Addr relasz; 102 Elf_Addr relaent; 103 Elf_Addr strsz; 104 Elf_Addr syment; 105 initfunc *init; 106 initfunc *fini; 107 const char *soname; 108 const char *rpath; 109 Elf_Addr symbolic; 110 Elf_Rel *rel; 111 Elf_Addr relsz; 112 Elf_Addr relent; 113 Elf_Addr pltrel; 114 Elf_Addr debug; 115 Elf_Addr textrel; 116 Elf_Addr jmprel; 117 Elf_Addr bind_now; 118 initarrayfunc **init_array; 119 initfunc **fini_array; 120 Elf_Addr init_arraysz; 121 Elf_Addr fini_arraysz; 122 const char *runpath; 123 Elf_Addr flags; 124 Elf_Addr encoding; 125 initarrayfunc **preinit_array; 126 Elf_Addr preinit_arraysz; 127 } u; 128 } Dyn; 129 #define dyn Dyn.u 130 131 Elf_Addr relacount; /* DT_RELACOUNT */ 132 Elf_Addr relcount; /* DT_RELCOUNT */ 133 134 int status; 135 #define STAT_RELOC_DONE 0x01 136 #define STAT_GOT_DONE 0x02 137 #define STAT_INIT_DONE 0x04 138 #define STAT_FINI_DONE 0x08 139 #define STAT_FINI_READY 0x10 140 #define STAT_UNLOADED 0x20 141 #define STAT_NODELETE 0x40 142 #define STAT_VISITED 0x80 143 #define STAT_GNU_HASH 0x100 144 145 Elf_Phdr *phdrp; 146 int phdrc; 147 148 int obj_type; 149 #define OBJTYPE_LDR 1 150 #define OBJTYPE_EXE 2 151 #define OBJTYPE_LIB 3 152 #define OBJTYPE_DLO 4 153 int obj_flags; /* c.f. <sys/exec_elf.h> DF_1_* */ 154 155 /* shared by ELF and GNU hash */ 156 u_int32_t nbuckets; 157 u_int32_t nchains; /* really, number of symbols */ 158 union { 159 struct { 160 /* specific to ELF hash */ 161 const Elf_Hash_Word *buckets; 162 const Elf_Hash_Word *chains; 163 } u_elf; 164 struct { 165 /* specific to GNU hash */ 166 const Elf_Word *buckets; 167 const Elf_Word *chains; 168 const Elf_Addr *bloom; 169 Elf_Word mask_bm; 170 Elf_Word shift2; 171 Elf_Word symndx; 172 } u_gnu; 173 } hash_u; 174 #define buckets_elf hash_u.u_elf.buckets 175 #define chains_elf hash_u.u_elf.chains 176 #define buckets_gnu hash_u.u_gnu.buckets 177 #define chains_gnu hash_u.u_gnu.chains 178 #define bloom_gnu hash_u.u_gnu.bloom 179 #define mask_bm_gnu hash_u.u_gnu.mask_bm 180 #define shift2_gnu hash_u.u_gnu.shift2 181 #define symndx_gnu hash_u.u_gnu.symndx 182 183 TAILQ_HEAD(,dep_node) child_list; /* direct dep libs of object */ 184 TAILQ_HEAD(,dep_node) grpsym_list; /* ordered complete dep list */ 185 TAILQ_HEAD(,dep_node) grpref_list; /* refs to other load groups */ 186 187 int refcount; /* dep libs only */ 188 int opencount; /* # dlopen() & exe */ 189 int grprefcount; /* load group refs */ 190 #define OBJECT_REF_CNT(object) \ 191 ((object->refcount + object->opencount + object->grprefcount)) 192 #define OBJECT_DLREF_CNT(object) \ 193 ((object->opencount + object->grprefcount)) 194 195 /* object that caused this module to be loaded, used in symbol lookup */ 196 elf_object_t *load_object; 197 struct sod sod; 198 199 /* for object confirmation */ 200 dev_t dev; 201 ino_t inode; 202 203 /* thread local storage info */ 204 Elf_Addr tls_fsize; 205 Elf_Addr tls_msize; 206 Elf_Addr tls_align; 207 const void *tls_static_data; 208 int tls_offset; 209 210 /* relro bits */ 211 Elf_Addr relro_addr; 212 Elf_Addr relro_size; 213 214 /* generation number of last grpsym insert on this object */ 215 unsigned int grpsym_gen; 216 217 char **rpath; 218 char **runpath; 219 220 /* nonzero if trace enabled for this object */ 221 int traced; 222 }; 223 224 struct dep_node { 225 TAILQ_ENTRY(dep_node) next_sib; 226 elf_object_t *data; 227 }; 228 229 230 /* Please don't rename or make hidden; gdb(1) knows about these. */ 231 Elf_Addr _dl_bind(elf_object_t *object, int index); 232 void _dl_debug_state(void); 233 234 /* exported to the application */ 235 extern char *__progname; 236 237 __BEGIN_HIDDEN_DECLS 238 void _dl_add_object(elf_object_t *object); 239 elf_object_t *_dl_finalize_object(const char *objname, Elf_Dyn *dynp, 240 Elf_Phdr *phdrp, int phdrc, const int objtype, const long lbase, 241 const long obase); 242 void _dl_remove_object(elf_object_t *object); 243 void _dl_cleanup_objects(void); 244 245 elf_object_t *_dl_load_shlib(const char *, elf_object_t *, int, int); 246 elf_object_t *_dl_tryload_shlib(const char *libname, int type, int flags); 247 248 int _dl_md_reloc(elf_object_t *object, int rel, int relsz); 249 int _dl_md_reloc_got(elf_object_t *object, int lazy); 250 251 Elf_Addr _dl_find_symbol(const char *name, const Elf_Sym **this, 252 int flags, const Elf_Sym *ref_sym, elf_object_t *object, 253 const elf_object_t **pobj); 254 Elf_Addr _dl_find_symbol_bysym(elf_object_t *req_obj, unsigned int symidx, 255 const Elf_Sym **ref, int flags, const Elf_Sym *ref_sym, 256 const elf_object_t **pobj); 257 /* 258 * defines for _dl_find_symbol() flag field, three bits of meaning 259 * myself - clear: search all objects, set: search only this object 260 * warnnotfound - clear: no warning, set: warn if not found 261 * inplt - clear: possible plt ref set: real matching function. 262 * 263 * inplt - due to how ELF handles function addresses in shared libraries 264 * &func may actually refer to the plt entry in the main program 265 * rather than the actual function address in the .so file. 266 * This rather bizarre behavior is documented in the SVR4 ABI. 267 * when getting the function address to relocate a PLT entry 268 * the 'real' function address is necessary, not the possible PLT address. 269 */ 270 /* myself */ 271 #define SYM_SEARCH_ALL 0x00 272 #define SYM_SEARCH_SELF 0x01 273 #define SYM_SEARCH_OTHER 0x02 274 #define SYM_SEARCH_NEXT 0x04 275 /* warnnotfound */ 276 #define SYM_NOWARNNOTFOUND 0x00 277 #define SYM_WARNNOTFOUND 0x10 278 /* inplt */ 279 #define SYM_NOTPLT 0x00 280 #define SYM_PLT 0x20 281 282 #define SYM_DLSYM 0x40 283 284 int _dl_load_dep_libs(elf_object_t *object, int flags, int booting); 285 int _dl_rtld(elf_object_t *object); 286 void _dl_call_init(elf_object_t *object); 287 void _dl_link_child(elf_object_t *dep, elf_object_t *p); 288 void _dl_link_grpsym(elf_object_t *object, int checklist); 289 void _dl_cache_grpsym_list(elf_object_t *object); 290 void _dl_cache_grpsym_list_setup(elf_object_t *object); 291 void _dl_link_grpref(elf_object_t *load_group, elf_object_t *load_object); 292 void _dl_link_dlopen(elf_object_t *dep); 293 void _dl_unlink_dlopen(elf_object_t *dep); 294 void _dl_notify_unload_shlib(elf_object_t *object); 295 void _dl_unload_shlib(elf_object_t *object); 296 void _dl_unload_dlopen(void); 297 298 void _dl_run_all_dtors(void); 299 300 int _dl_match_file(struct sod *sodp, const char *name, int namelen); 301 char *_dl_find_shlib(struct sod *sodp, char **searchpath, int nohints); 302 void _dl_load_list_free(struct load_list *load_list); 303 304 typedef void lock_cb(int); 305 void _dl_thread_kern_go(lock_cb *); 306 lock_cb *_dl_thread_kern_stop(void); 307 308 char *_dl_getenv(const char *, char **) __boot; 309 void _dl_unsetenv(const char *, char **) __boot; 310 311 void _dl_trace_setup(char **) __boot; 312 void _dl_trace_object_setup(elf_object_t *); 313 int _dl_trace_plt(const elf_object_t *, const char *); 314 315 /* tib.c */ 316 void _dl_allocate_tls_offsets(void) __boot; 317 void _dl_allocate_first_tib(void) __boot; 318 void _dl_set_tls(elf_object_t *_object, Elf_Phdr *_ptls, Elf_Addr _libaddr, 319 const char *_libname); 320 extern int _dl_tib_static_done; 321 322 extern elf_object_t *_dl_objects; 323 extern elf_object_t *_dl_last_object; 324 325 extern elf_object_t *_dl_loading_object; 326 327 extern struct r_debug *_dl_debug_map; 328 329 extern int _dl_pagesz; 330 extern int _dl_errno; 331 332 extern char **_dl_libpath; 333 334 extern int _dl_bindnow; 335 extern int _dl_traceld; 336 extern int _dl_debug; 337 338 extern char *_dl_preload; 339 extern char *_dl_tracefmt1; 340 extern char *_dl_tracefmt2; 341 extern char *_dl_traceprog; 342 343 extern int _dl_trust; 344 345 #define DL_DEB(P) do { if (_dl_debug) _dl_printf P ; } while (0) 346 347 #define DL_NOT_FOUND 1 348 #define DL_CANT_OPEN 2 349 #define DL_NOT_ELF 3 350 #define DL_CANT_OPEN_REF 4 351 #define DL_CANT_MMAP 5 352 #define DL_NO_SYMBOL 6 353 #define DL_INVALID_HANDLE 7 354 #define DL_INVALID_CTL 8 355 #define DL_NO_OBJECT 9 356 #define DL_CANT_FIND_OBJ 10 357 #define DL_CANT_LOAD_OBJ 11 358 #define DL_INVALID_MODE 12 359 360 #define ELF_ROUND(x,malign) (((x) + (malign)-1) & ~((malign)-1)) 361 #define ELF_TRUNC(x,malign) ((x) & ~((malign)-1)) 362 363 /* symbol lookup cache */ 364 typedef struct sym_cache { 365 const elf_object_t *obj; 366 const Elf_Sym *sym; 367 int flags; 368 } sym_cache; 369 370 extern sym_cache *_dl_symcache; 371 extern int _dl_symcachestat_hits; 372 extern int _dl_symcachestat_lookups; 373 TAILQ_HEAD(dlochld, dep_node); 374 extern struct dlochld _dlopened_child_list; 375 __END_HIDDEN_DECLS 376 377 #endif /* _RESOLVE_H_ */ 378