1 /* $OpenBSD: resolve.h,v 1.70 2013/11/13 05:41:42 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 <link.h> 34 #include <dlfcn.h> 35 #include <signal.h> 36 37 struct load_list { 38 struct load_list *next; 39 void *start; 40 size_t size; 41 int prot; 42 Elf_Addr moff; 43 long foff; 44 }; 45 46 /* 47 * Structure describing a loaded object. 48 * The head of this struct must be compatible 49 * with struct link_map in sys/link.h 50 */ 51 typedef struct elf_object elf_object_t; 52 struct elf_object { 53 Elf_Addr obj_base; /* object's address '0' base */ 54 char *load_name; /* Pointer to object name */ 55 Elf_Dyn *load_dyn; /* Pointer to object dynamic data */ 56 struct elf_object *next; 57 struct elf_object *prev; 58 /* End struct link_map compatible */ 59 Elf_Addr load_base; /* Base address of loadable segments */ 60 61 struct load_list *load_list; 62 63 u_int32_t load_size; 64 Elf_Addr got_addr; 65 Elf_Addr got_start; 66 size_t got_size; 67 Elf_Addr plt_start; 68 size_t plt_size; 69 70 union { 71 u_long info[DT_NUM + DT_PROCNUM]; 72 struct { 73 Elf_Addr null; /* Not used */ 74 Elf_Addr needed; /* Not used */ 75 Elf_Addr pltrelsz; 76 Elf_Addr *pltgot; 77 Elf_Addr *hash; 78 const char *strtab; 79 const Elf_Sym *symtab; 80 Elf_RelA *rela; 81 Elf_Addr relasz; 82 Elf_Addr relaent; 83 Elf_Addr strsz; 84 Elf_Addr syment; 85 void (*init)(void); 86 void (*fini)(void); 87 const char *soname; 88 const char *rpath; 89 Elf_Addr symbolic; 90 Elf_Rel *rel; 91 Elf_Addr relsz; 92 Elf_Addr relent; 93 Elf_Addr pltrel; 94 Elf_Addr debug; 95 Elf_Addr textrel; 96 Elf_Addr jmprel; 97 } u; 98 } Dyn; 99 #define dyn Dyn.u 100 101 Elf_Addr relacount; /* DT_RELACOUNT */ 102 Elf_Addr relcount; /* DT_RELCOUNT */ 103 104 int status; 105 #define STAT_RELOC_DONE 0x01 106 #define STAT_GOT_DONE 0x02 107 #define STAT_INIT_DONE 0x04 108 #define STAT_FINI_DONE 0x08 109 #define STAT_FINI_READY 0x10 110 #define STAT_UNLOADED 0x20 111 #define STAT_NODELETE 0x40 112 #define STAT_VISITED 0x80 113 114 Elf_Phdr *phdrp; 115 int phdrc; 116 117 int obj_type; 118 #define OBJTYPE_LDR 1 119 #define OBJTYPE_EXE 2 120 #define OBJTYPE_LIB 3 121 #define OBJTYPE_DLO 4 122 int obj_flags; /* c.f. <sys/exec_elf.h> DF_1_* */ 123 124 Elf_Word *buckets; 125 u_int32_t nbuckets; 126 Elf_Word *chains; 127 u_int32_t nchains; 128 Elf_Dyn *dynamic; 129 130 TAILQ_HEAD(,dep_node) child_list; /* direct dep libs of object */ 131 TAILQ_HEAD(,dep_node) grpsym_list; /* ordered complete dep list */ 132 TAILQ_HEAD(,dep_node) grpref_list; /* refs to other load groups */ 133 134 int refcount; /* dep libs only */ 135 int opencount; /* # dlopen() & exe */ 136 int grprefcount; /* load group refs */ 137 #define OBJECT_REF_CNT(object) \ 138 ((object->refcount + object->opencount + object->grprefcount)) 139 #define OBJECT_DLREF_CNT(object) \ 140 ((object->opencount + object->grprefcount)) 141 142 /* object that caused this module to be loaded, used in symbol lookup */ 143 elf_object_t *load_object; 144 struct sod sod; 145 146 void *prebind_data; 147 148 /* for object confirmation */ 149 dev_t dev; 150 ino_t inode; 151 152 /* last symbol lookup on this object, to avoid mutiple searches */ 153 int lastlookup_head; 154 int lastlookup; 155 156 char **rpath; 157 158 /* nonzero if trace enabled for this object */ 159 int traced; 160 }; 161 162 struct dep_node { 163 TAILQ_ENTRY(dep_node) next_sib; 164 elf_object_t *data; 165 }; 166 167 void _dl_add_object(elf_object_t *object); 168 elf_object_t *_dl_finalize_object(const char *objname, Elf_Dyn *dynp, 169 Elf_Phdr *phdrp, int phdrc, const int objtype, const long lbase, 170 const long obase); 171 void _dl_remove_object(elf_object_t *object); 172 void _dl_cleanup_objects(void); 173 174 elf_object_t *_dl_load_shlib(const char *, elf_object_t *, int, int); 175 elf_object_t *_dl_tryload_shlib(const char *libname, int type, int flags); 176 177 int _dl_md_reloc(elf_object_t *object, int rel, int relsz); 178 int _dl_md_reloc_got(elf_object_t *object, int lazy); 179 180 Elf_Addr _dl_find_symbol(const char *name, const Elf_Sym **this, 181 int flags, const Elf_Sym *ref_sym, elf_object_t *object, 182 const elf_object_t **pobj); 183 Elf_Addr _dl_find_symbol_bysym(elf_object_t *req_obj, unsigned int symidx, 184 const Elf_Sym **ref, int flags, const Elf_Sym *ref_sym, 185 const elf_object_t **pobj); 186 /* 187 * defines for _dl_find_symbol() flag field, three bits of meaning 188 * myself - clear: search all objects, set: search only this object 189 * warnnotfound - clear: no warning, set: warn if not found 190 * inplt - clear: possible plt ref set: real matching function. 191 * 192 * inplt - due to how ELF handles function addresses in shared libraries 193 * &func may actually refer to the plt entry in the main program 194 * rather than the actual function address in the .so file. 195 * This rather bizarre behavior is documented in the SVR4 ABI. 196 * when getting the function address to relocate a PLT entry 197 * the 'real' function address is necessary, not the possible PLT address. 198 */ 199 /* myself */ 200 #define SYM_SEARCH_ALL 0x00 201 #define SYM_SEARCH_SELF 0x01 202 #define SYM_SEARCH_OTHER 0x02 203 #define SYM_SEARCH_NEXT 0x04 204 #define SYM_SEARCH_OBJ 0x08 205 /* warnnotfound */ 206 #define SYM_NOWARNNOTFOUND 0x00 207 #define SYM_WARNNOTFOUND 0x10 208 /* inplt */ 209 #define SYM_NOTPLT 0x00 210 #define SYM_PLT 0x20 211 212 #define SYM_DLSYM 0x40 213 214 int _dl_load_dep_libs(elf_object_t *object, int flags, int booting); 215 int _dl_rtld(elf_object_t *object); 216 void _dl_call_init(elf_object_t *object); 217 void _dl_link_child(elf_object_t *dep, elf_object_t *p); 218 void _dl_link_grpsym(elf_object_t *object, int checklist); 219 void _dl_cache_grpsym_list(elf_object_t *object); 220 void _dl_cache_grpsym_list_setup(elf_object_t *object); 221 void _dl_link_grpref(elf_object_t *load_group, elf_object_t *load_object); 222 void _dl_link_dlopen(elf_object_t *dep); 223 void _dl_unlink_dlopen(elf_object_t *dep); 224 void _dl_notify_unload_shlib(elf_object_t *object); 225 void _dl_unload_shlib(elf_object_t *object); 226 void _dl_unload_dlopen(void); 227 228 void _dl_run_all_dtors(void); 229 230 /* Please don't rename; gdb(1) knows about this. */ 231 Elf_Addr _dl_bind(elf_object_t *object, int index); 232 233 int _dl_match_file(struct sod *sodp, const char *name, int namelen); 234 char *_dl_find_shlib(struct sod *sodp, char **searchpath, int nohints); 235 void _dl_load_list_free(struct load_list *load_list); 236 void _dl_debug_state(void); 237 238 void _dl_thread_kern_go(void); 239 void _dl_thread_kern_stop(void); 240 241 void _dl_thread_bind_lock(int, sigset_t *); 242 243 char *_dl_getenv(const char *, char **); 244 void _dl_unsetenv(const char *, char **); 245 246 void _dl_trace_setup(char **); 247 void _dl_trace_object_setup(elf_object_t *); 248 int _dl_trace_plt(const elf_object_t *, const char *); 249 250 extern elf_object_t *_dl_objects; 251 extern elf_object_t *_dl_last_object; 252 253 extern elf_object_t *_dl_loading_object; 254 255 extern const char *_dl_progname; 256 extern struct r_debug *_dl_debug_map; 257 258 extern int _dl_pagesz; 259 extern int _dl_errno; 260 261 extern char **_dl_libpath; 262 263 extern char *_dl_preload; 264 extern char *_dl_bindnow; 265 extern char *_dl_traceld; 266 extern char *_dl_tracefmt1; 267 extern char *_dl_tracefmt2; 268 extern char *_dl_traceprog; 269 extern char *_dl_debug; 270 271 extern int _dl_trust; 272 273 #define DL_DEB(P) do { if (_dl_debug) _dl_printf P ; } while (0) 274 275 #define DL_NOT_FOUND 1 276 #define DL_CANT_OPEN 2 277 #define DL_NOT_ELF 3 278 #define DL_CANT_OPEN_REF 4 279 #define DL_CANT_MMAP 5 280 #define DL_NO_SYMBOL 6 281 #define DL_INVALID_HANDLE 7 282 #define DL_INVALID_CTL 8 283 #define DL_NO_OBJECT 9 284 #define DL_CANT_FIND_OBJ 10 285 #define DL_CANT_LOAD_OBJ 11 286 #define DL_INVALID_MODE 12 287 288 #define ELF_ROUND(x,malign) (((x) + (malign)-1) & ~((malign)-1)) 289 #define ELF_TRUNC(x,malign) ((x) & ~((malign)-1)) 290 291 /* symbol lookup cache */ 292 typedef struct sym_cache { 293 const elf_object_t *obj; 294 const Elf_Sym *sym; 295 int flags; 296 } sym_cache; 297 298 extern sym_cache *_dl_symcache; 299 extern int _dl_symcachestat_hits; 300 extern int _dl_symcachestat_lookups; 301 TAILQ_HEAD(dlochld, dep_node); 302 extern struct dlochld _dlopened_child_list; 303 304 /* variables used to avoid duplicate node checking */ 305 int _dl_searchnum; 306 uint32_t _dl_skipnum; 307 void _dl_newsymsearch(void); 308 309 #endif /* _RESOLVE_H_ */ 310