1 /* $OpenBSD: resolve.h,v 1.41 2005/09/28 15:41:06 drahn 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 36 struct load_list { 37 struct load_list *next; 38 void *start; 39 size_t size; 40 int prot; 41 Elf_Addr moff; 42 long foff; 43 }; 44 45 /* 46 * Structure describing a loaded object. 47 * The head of this struct must be compatible 48 * with struct link_map in sys/link.h 49 */ 50 typedef struct elf_object elf_object_t; 51 struct elf_object { 52 Elf_Addr load_addr; /* Real load address */ 53 char *load_name; /* Pointer to object name */ 54 Elf_Dyn *load_dyn; /* Pointer to object dynamic data */ 55 struct elf_object *next; 56 struct elf_object *prev; 57 /* End struct link_map compatible */ 58 Elf_Addr load_offs; /* Load offset from link address */ 59 60 struct load_list *load_list; 61 62 u_int32_t load_size; 63 Elf_Addr got_addr; 64 Elf_Addr got_start; 65 size_t got_size; 66 Elf_Addr plt_start; 67 size_t plt_size; 68 69 union { 70 u_long info[DT_NUM + DT_PROCNUM]; 71 struct { 72 Elf_Addr null; /* Not used */ 73 Elf_Addr needed; /* Not used */ 74 Elf_Addr pltrelsz; 75 Elf_Addr *pltgot; 76 Elf_Addr *hash; 77 const char *strtab; 78 const Elf_Sym *symtab; 79 Elf_RelA *rela; 80 Elf_Addr relasz; 81 Elf_Addr relaent; 82 Elf_Addr strsz; 83 Elf_Addr syment; 84 void (*init)(void); 85 void (*fini)(void); 86 const char *soname; 87 const char *rpath; 88 Elf_Addr symbolic; 89 Elf_Rel *rel; 90 Elf_Addr relsz; 91 Elf_Addr relent; 92 Elf_Addr pltrel; 93 Elf_Addr debug; 94 Elf_Addr textrel; 95 Elf_Addr jmprel; 96 Elf_Addr bind_now; 97 } u; 98 } Dyn; 99 #define dyn Dyn.u 100 101 struct elf_object *dep_next; /* Shadow objects for resolve search */ 102 103 int status; 104 #define STAT_RELOC_DONE 0x01 105 #define STAT_GOT_DONE 0x02 106 #define STAT_INIT_DONE 0x04 107 #define STAT_FINI_DONE 0x08 108 #define STAT_FINI_READY 0x10 109 110 Elf_Phdr *phdrp; 111 int phdrc; 112 113 int refcount; 114 int obj_type; 115 #define OBJTYPE_LDR 1 116 #define OBJTYPE_EXE 2 117 #define OBJTYPE_LIB 3 118 #define OBJTYPE_DLO 4 119 int obj_flags; 120 121 Elf_Word *buckets; 122 u_int32_t nbuckets; 123 Elf_Word *chains; 124 u_int32_t nchains; 125 Elf_Dyn *dynamic; 126 127 TAILQ_HEAD(,dep_node) child_list; 128 TAILQ_HEAD(,dep_node) dload_list; 129 130 int opencount; /* # dlopen() */ 131 132 /* object that caused this module to be loaded, used in symbol lookup */ 133 elf_object_t *load_object; 134 135 /* for object confirmation */ 136 dev_t dev; 137 ino_t inode; 138 }; 139 140 struct dep_node { 141 TAILQ_ENTRY(dep_node) next_sib; 142 elf_object_t *data; 143 }; 144 145 void _dl_rt_resolve(void); 146 147 void _dl_add_object(elf_object_t *object); 148 elf_object_t *_dl_finalize_object(const char *objname, Elf_Dyn *dynp, 149 const long *, const int objtype, const long laddr, const long loff); 150 void _dl_remove_object(elf_object_t *object); 151 152 elf_object_t *_dl_lookup_object(const char *objname); 153 elf_object_t *_dl_load_shlib(const char *, elf_object_t *, int, int); 154 elf_object_t *_dl_tryload_shlib(const char *libname, int type, int flags); 155 156 int _dl_md_reloc(elf_object_t *object, int rel, int relsz); 157 void _dl_md_reloc_got(elf_object_t *object, int lazy); 158 159 Elf_Addr _dl_find_symbol(const char *name, const Elf_Sym **this, 160 int flags, const Elf_Sym *ref_sym, elf_object_t *object, 161 const elf_object_t **pobj); 162 Elf_Addr _dl_find_symbol_bysym(elf_object_t *req_obj, unsigned int symidx, 163 const Elf_Sym **ref, int flags, const Elf_Sym *ref_sym, 164 const elf_object_t **pobj); 165 /* 166 * defines for _dl_find_symbol() flag field, three bits of meaning 167 * myself - clear: search all objects, set: search only this object 168 * warnnotfound - clear: no warning, set: warn if not found 169 * inplt - clear: possible plt ref set: real matching function. 170 * 171 * inplt - due to how ELF handles function addresses in shared libraries 172 * &func may actually refer to the plt entry in the main program 173 * rather than the actual function address in the .so file. 174 * This rather bizarre behavior is documented in the SVR4 ABI. 175 * when getting the function address to relocate a PLT entry 176 * the 'real' function address is necessary, not the possible PLT address. 177 */ 178 /* myself */ 179 #define SYM_SEARCH_ALL 0x00 180 #define SYM_SEARCH_SELF 0x01 181 #define SYM_SEARCH_OTHER 0x02 182 #define SYM_SEARCH_NEXT 0x04 183 #define SYM_SEARCH_OBJ 0x08 184 /* warnnotfound */ 185 #define SYM_NOWARNNOTFOUND 0x00 186 #define SYM_WARNNOTFOUND 0x10 187 /* inplt */ 188 #define SYM_NOTPLT 0x00 189 #define SYM_PLT 0x20 190 191 #define SYM_DLSYM 0x40 192 193 int _dl_rtld(elf_object_t *object); 194 void _dl_call_init(elf_object_t *object); 195 void _dl_link_sub(elf_object_t *dep, elf_object_t *p); 196 void _dl_link_dlopen(elf_object_t *dep); 197 void _dl_unlink_dlopen(elf_object_t *dep); 198 void _dl_notify_unload_shlib(elf_object_t *object); 199 void _dl_unload_shlib(elf_object_t *object); 200 void _dl_unload_dlopen(void); 201 202 void _dl_run_dtors(elf_object_t *object); 203 void _dl_run_all_dtors(void); 204 205 Elf_Addr _dl_bind(elf_object_t *object, int index); 206 207 int _dl_match_file(struct sod *sodp, char *name, int namelen); 208 char *_dl_find_shlib(struct sod *sodp, const char *searchpath, int nohints); 209 void _dl_load_list_free(struct load_list *load_list); 210 211 void _dl_thread_kern_go(void); 212 void _dl_thread_kern_stop(void); 213 214 extern elf_object_t *_dl_objects; 215 extern elf_object_t *_dl_last_object; 216 217 extern elf_object_t *_dl_loading_object; 218 219 extern const char *_dl_progname; 220 extern struct r_debug *_dl_debug_map; 221 222 extern int _dl_pagesz; 223 extern int _dl_errno; 224 extern int _dl_exiting; 225 226 extern char *_dl_libpath; 227 extern char *_dl_preload; 228 extern char *_dl_bindnow; 229 extern char *_dl_traceld; 230 extern char *_dl_debug; 231 232 #define DL_DEB(P) do { if (_dl_debug) _dl_printf P ; } while (0) 233 234 #define DL_NOT_FOUND 1 235 #define DL_CANT_OPEN 2 236 #define DL_NOT_ELF 3 237 #define DL_CANT_OPEN_REF 4 238 #define DL_CANT_MMAP 5 239 #define DL_NO_SYMBOL 6 240 #define DL_INVALID_HANDLE 7 241 #define DL_INVALID_CTL 8 242 #define DL_NO_OBJECT 9 243 #define DL_CANT_FIND_OBJ 10 244 #define DL_CANT_LOAD_OBJ 11 245 246 #define ELF_ROUND(x,malign) (((x) + (malign)-1) & ~((malign)-1)) 247 #define ELF_TRUNC(x,malign) ((x) & ~((malign)-1)) 248 249 /* symbol lookup cache */ 250 typedef struct sym_cache { 251 const elf_object_t *obj; 252 const Elf_Sym *sym; 253 int flags; 254 } sym_cache; 255 256 extern sym_cache *_dl_symcache; 257 extern int _dl_symcachestat_hits; 258 extern int _dl_symcachestat_lookups; 259 TAILQ_HEAD(dlochld, dep_node); 260 extern struct dlochld _dlopened_child_list; 261 262 263 #endif /* _RESOLVE_H_ */ 264