1 /* $OpenBSD: resolve.h,v 1.103 2022/12/04 15:42:07 deraadt 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_RELR + 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 typedef struct elf_object elf_object_t; 72 73 struct object_vector { 74 int len; 75 int alloc; 76 elf_object_t **vec; 77 }; 78 void object_vec_grow(struct object_vector *_vec, int _more); 79 80 struct mutate { 81 vaddr_t start; 82 vaddr_t end; 83 int valid; 84 }; 85 86 /* 87 * Structure describing a loaded object. 88 * The head of this struct must be compatible 89 * with struct link_map in <link_elf.h> 90 */ 91 struct elf_object { 92 Elf_Addr obj_base; /* object's address '0' base */ 93 char *load_name; /* Pointer to object name */ 94 Elf_Dyn *load_dyn; /* Pointer to object dynamic data */ 95 struct elf_object *next; 96 struct elf_object *prev; 97 /* End struct link_map compatible */ 98 Elf_Addr load_base; /* Base address of loadable segments */ 99 100 struct load_list *load_list; 101 102 u_int32_t load_size; 103 104 union { 105 u_long info[DT_NUM + DT_PROCNUM]; 106 struct { 107 Elf_Addr null; /* Not used */ 108 Elf_Addr needed; /* Not used */ 109 Elf_Addr pltrelsz; 110 Elf_Addr *pltgot; 111 Elf_Addr *hash; 112 const char *strtab; 113 const Elf_Sym *symtab; 114 Elf_RelA *rela; 115 Elf_Addr relasz; 116 Elf_Addr relaent; 117 Elf_Addr strsz; 118 Elf_Addr syment; 119 initfunc *init; 120 initfunc *fini; 121 const char *soname; 122 const char *rpath; 123 Elf_Addr symbolic; 124 Elf_Rel *rel; 125 Elf_Addr relsz; 126 Elf_Addr relent; 127 Elf_Addr pltrel; 128 Elf_Addr debug; 129 Elf_Addr textrel; 130 Elf_Addr jmprel; 131 Elf_Addr bind_now; 132 initarrayfunc **init_array; 133 initfunc **fini_array; 134 Elf_Addr init_arraysz; 135 Elf_Addr fini_arraysz; 136 const char *runpath; 137 Elf_Addr flags; 138 Elf_Addr encoding; 139 initarrayfunc **preinit_array; 140 Elf_Addr preinit_arraysz; 141 Elf_Addr unassigned; 142 Elf_Addr relrsz; 143 Elf_Relr *relr; 144 } u; 145 } Dyn; 146 #define dyn Dyn.u 147 148 Elf_Addr relacount; /* DT_RELACOUNT */ 149 Elf_Addr relcount; /* DT_RELCOUNT */ 150 151 int status; 152 #define STAT_RELOC_DONE 0x001 153 #define STAT_GOT_DONE 0x002 154 #define STAT_INIT_DONE 0x004 155 #define STAT_FINI_DONE 0x008 156 #define STAT_FINI_READY 0x010 157 #define STAT_UNLOADED 0x020 158 #define STAT_NODELETE 0x040 159 #define STAT_GNU_HASH 0x080 160 #define STAT_VISIT_INITFIRST 0x100 161 #define STAT_VISIT_INIT 0x200 162 163 Elf_Phdr *phdrp; 164 int phdrc; 165 166 int obj_type; 167 #define OBJTYPE_LDR 1 168 #define OBJTYPE_EXE 2 169 #define OBJTYPE_LIB 3 170 #define OBJTYPE_DLO 4 171 int obj_flags; /* c.f. <sys/exec_elf.h> DF_1_* */ 172 int nodelete; 173 174 /* shared by ELF and GNU hash */ 175 u_int32_t nbuckets; 176 u_int32_t nchains; /* really, number of symbols */ 177 union { 178 struct { 179 /* specific to ELF hash */ 180 const Elf_Hash_Word *buckets; 181 const Elf_Hash_Word *chains; 182 } u_elf; 183 struct { 184 /* specific to GNU hash */ 185 const Elf_Word *buckets; 186 const Elf_Word *chains; 187 const Elf_Addr *bloom; 188 Elf_Word mask_bm; 189 Elf_Word shift2; 190 Elf_Word symndx; 191 } u_gnu; 192 } hash_u; 193 #define buckets_elf hash_u.u_elf.buckets 194 #define chains_elf hash_u.u_elf.chains 195 #define buckets_gnu hash_u.u_gnu.buckets 196 #define chains_gnu hash_u.u_gnu.chains 197 #define bloom_gnu hash_u.u_gnu.bloom 198 #define mask_bm_gnu hash_u.u_gnu.mask_bm 199 #define shift2_gnu hash_u.u_gnu.shift2 200 #define symndx_gnu hash_u.u_gnu.symndx 201 202 struct object_vector child_vec; /* direct dep libs of object */ 203 struct object_vector grpsym_vec; /* ordered complete dep list */ 204 TAILQ_HEAD(,dep_node) grpref_list; /* refs to other load groups */ 205 206 int refcount; /* dep libs only */ 207 int opencount; /* # dlopen() & exe */ 208 int grprefcount; /* load group refs */ 209 #define OBJECT_REF_CNT(object) \ 210 ((object->refcount + object->opencount + object->grprefcount)) 211 #define OBJECT_DLREF_CNT(object) \ 212 ((object->opencount + object->grprefcount)) 213 214 /* object that caused this module to be loaded, used in symbol lookup */ 215 elf_object_t *load_object; 216 struct sod sod; 217 218 /* for object confirmation */ 219 dev_t dev; 220 ino_t inode; 221 222 /* thread local storage info */ 223 Elf_Addr tls_fsize; 224 Elf_Addr tls_msize; 225 Elf_Addr tls_align; 226 const void *tls_static_data; 227 int tls_offset; 228 229 /* relro bits */ 230 Elf_Addr relro_addr; 231 Elf_Addr relro_size; 232 233 /* generation number of last grpsym insert on this object */ 234 unsigned int grpsym_gen; 235 236 char **rpath; 237 char **runpath; 238 239 /* nonzero if trace enabled for this object */ 240 int traced; 241 242 #define MAXMUT 40 243 struct mutate imut[MAXMUT]; 244 struct mutate mut[MAXMUT]; 245 }; 246 247 struct dep_node { 248 TAILQ_ENTRY(dep_node) next_sib; 249 elf_object_t *data; 250 }; 251 252 253 /* Please don't rename or make hidden; gdb(1) knows about these. */ 254 Elf_Addr _dl_bind(elf_object_t *object, int index); 255 void _dl_debug_state(void); 256 257 /* exported to the application */ 258 extern char *__progname; 259 260 __BEGIN_HIDDEN_DECLS 261 void _dl_handle_nodelete(elf_object_t *_object); 262 void _dl_add_object(elf_object_t *object); 263 elf_object_t *_dl_finalize_object(const char *objname, Elf_Dyn *dynp, 264 Elf_Phdr *phdrp, int phdrc, const int objtype, const long lbase, 265 const long obase); 266 void _dl_remove_object(elf_object_t *object); 267 void _dl_cleanup_objects(void); 268 269 void _dl_handle_already_loaded(elf_object_t *_object, int _flags); 270 elf_object_t *_dl_load_shlib(const char *, elf_object_t *, 271 int, int, int nodelete); 272 elf_object_t *_dl_tryload_shlib(const char *libname, int type, 273 int flags, int nodelete); 274 275 int _dl_md_reloc(elf_object_t *object, int rel, int relsz); 276 int _dl_md_reloc_got(elf_object_t *object, int lazy); 277 278 struct sym_res { 279 const Elf_Sym *sym; 280 const elf_object_t *obj; 281 }; 282 283 struct sym_res _dl_find_symbol(const char *name, int flags, 284 const Elf_Sym *ref_sym, elf_object_t *object); 285 286 /* 287 * defines for _dl_find_symbol() flag field, three bits of meaning 288 * myself - clear: search all objects, set: search only this object 289 * warnnotfound - clear: no warning, set: warn if not found 290 * inplt - clear: possible plt ref set: real matching function. 291 * 292 * inplt - due to how ELF handles function addresses in shared libraries 293 * &func may actually refer to the plt entry in the main program 294 * rather than the actual function address in the .so file. 295 * This rather bizarre behavior is documented in the SVR4 ABI. 296 * when getting the function address to relocate a PLT entry 297 * the 'real' function address is necessary, not the possible PLT address. 298 */ 299 /* myself */ 300 #define SYM_SEARCH_ALL 0x00 301 #define SYM_SEARCH_SELF 0x01 302 #define SYM_SEARCH_OTHER 0x02 303 #define SYM_SEARCH_NEXT 0x04 304 /* warnnotfound */ 305 #define SYM_NOWARNNOTFOUND 0x00 306 #define SYM_WARNNOTFOUND 0x10 307 /* inplt */ 308 #define SYM_NOTPLT 0x00 309 #define SYM_PLT 0x20 310 311 #define SYM_DLSYM 0x40 312 313 int _dl_load_dep_libs(elf_object_t *object, int flags, int booting); 314 int _dl_rtld(elf_object_t *object); 315 void _dl_call_init(elf_object_t *object); 316 void _dl_link_child(elf_object_t *dep, elf_object_t *p); 317 void _dl_link_grpsym(elf_object_t *object); 318 void _dl_cache_grpsym_list_setup(elf_object_t *_object); 319 void _dl_link_grpref(elf_object_t *load_group, elf_object_t *load_object); 320 void _dl_link_dlopen(elf_object_t *dep); 321 void _dl_unlink_dlopen(elf_object_t *dep); 322 void _dl_notify_unload_shlib(elf_object_t *object); 323 void _dl_unload_shlib(elf_object_t *object); 324 void _dl_unload_dlopen(void); 325 326 void _dl_run_all_dtors(void); 327 328 int _dl_match_file(struct sod *sodp, const char *name, int namelen); 329 char *_dl_find_shlib(struct sod *sodp, char **searchpath, int nohints); 330 void _dl_load_list_free(struct load_list *load_list); 331 332 void _dl_find_immutables(int type, elf_object_t *object, Elf_Ehdr *); 333 void _dl_defer_mut(struct mutate *m, vaddr_t start, vsize_t len); 334 void _dl_defer_immut(struct mutate *m, vaddr_t start, vsize_t len); 335 void _dl_apply_immutable(elf_object_t *object); 336 337 typedef void lock_cb(int); 338 void _dl_thread_kern_go(lock_cb *); 339 lock_cb *_dl_thread_kern_stop(void); 340 341 char *_dl_getenv(const char *, char **) __boot; 342 void _dl_unsetenv(const char *, char **) __boot; 343 344 void _dl_trace_setup(char **) __boot; 345 void _dl_trace_object_setup(elf_object_t *); 346 int _dl_trace_plt(const elf_object_t *, const char *); 347 348 /* tib.c */ 349 void _dl_allocate_tls_offsets(void) __boot; 350 void _dl_allocate_first_tib(void) __boot; 351 void _dl_set_tls(elf_object_t *_object, Elf_Phdr *_ptls, Elf_Addr _libaddr, 352 const char *_libname); 353 extern int _dl_tib_static_done; 354 355 extern elf_object_t *_dl_objects; 356 extern int object_count; /* how many objects are currently loaded */ 357 358 extern elf_object_t *_dl_loading_object; 359 360 extern struct r_debug *_dl_debug_map; 361 362 extern int _dl_pagesz; 363 extern int _dl_errno; 364 365 extern char **_dl_libpath; 366 367 extern int _dl_bindnow; 368 extern int _dl_traceld; 369 extern int _dl_debug; 370 371 extern char *_dl_preload; 372 extern char *_dl_tracefmt1; 373 extern char *_dl_tracefmt2; 374 extern char *_dl_traceprog; 375 376 extern void *_dl_exec_hint; 377 378 extern int _dl_trust; 379 380 #define DL_DEB(P) do { if (_dl_debug) _dl_printf P ; } while (0) 381 382 #define DL_NOT_FOUND 1 383 #define DL_CANT_OPEN 2 384 #define DL_NOT_ELF 3 385 #define DL_CANT_OPEN_REF 4 386 #define DL_CANT_MMAP 5 387 #define DL_NO_SYMBOL 6 388 #define DL_INVALID_HANDLE 7 389 #define DL_INVALID_CTL 8 390 #define DL_NO_OBJECT 9 391 #define DL_CANT_FIND_OBJ 10 392 #define DL_CANT_LOAD_OBJ 11 393 #define DL_INVALID_MODE 12 394 395 #define ELF_ROUND(x,malign) (((x) + (malign)-1) & ~((malign)-1)) 396 #define ELF_TRUNC(x,malign) ((x) & ~((malign)-1)) 397 398 /* symbol lookup cache */ 399 typedef struct sym_cache { 400 const elf_object_t *obj; 401 const Elf_Sym *sym; 402 int flags; 403 } sym_cache; 404 405 TAILQ_HEAD(dlochld, dep_node); 406 extern struct dlochld _dlopened_child_list; 407 __END_HIDDEN_DECLS 408 409 #endif /* _RESOLVE_H_ */ 410