1 /*- 2 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 * 25 * $FreeBSD$ 26 */ 27 28 #ifndef RTLD_H /* { */ 29 #define RTLD_H 1 30 31 #include <machine/elf.h> 32 #include <sys/types.h> 33 #include <sys/queue.h> 34 35 #include <elf-hints.h> 36 #include <link.h> 37 #include <stdarg.h> 38 #include <setjmp.h> 39 #include <stddef.h> 40 41 #include "rtld_lock.h" 42 #include "rtld_machdep.h" 43 44 #ifndef STANDARD_LIBRARY_PATH 45 #define STANDARD_LIBRARY_PATH "/lib:/usr/lib" 46 #endif 47 48 #define NEW(type) ((type *) xmalloc(sizeof(type))) 49 #define CNEW(type) ((type *) xcalloc(1, sizeof(type))) 50 51 /* We might as well do booleans like C++. */ 52 typedef unsigned char bool; 53 #define false 0 54 #define true 1 55 56 extern size_t tls_last_offset; 57 extern size_t tls_last_size; 58 extern size_t tls_static_space; 59 extern int tls_dtv_generation; 60 extern int tls_max_index; 61 62 extern int main_argc; 63 extern char **main_argv; 64 extern char **environ; 65 extern const char *__ld_sharedlib_base; 66 67 struct stat; 68 struct Struct_Obj_Entry; 69 70 /* Lists of shared objects */ 71 typedef struct Struct_Objlist_Entry { 72 STAILQ_ENTRY(Struct_Objlist_Entry) link; 73 struct Struct_Obj_Entry *obj; 74 } Objlist_Entry; 75 76 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 77 78 /* Types of init and fini functions */ 79 typedef void (*InitFunc)(void); 80 typedef void (*InitArrFunc)(int, char **, char **); 81 82 /* Lists of shared object dependencies */ 83 typedef struct Struct_Needed_Entry { 84 struct Struct_Needed_Entry *next; 85 struct Struct_Obj_Entry *obj; 86 unsigned long name; /* Offset of name in string table */ 87 } Needed_Entry; 88 89 typedef struct Struct_Name_Entry { 90 STAILQ_ENTRY(Struct_Name_Entry) link; 91 char name[1]; 92 } Name_Entry; 93 94 /* Lock object */ 95 typedef struct Struct_LockInfo { 96 void *context; /* Client context for creating locks */ 97 void *thelock; /* The one big lock */ 98 /* Debugging aids. */ 99 volatile int rcount; /* Number of readers holding lock */ 100 volatile int wcount; /* Number of writers holding lock */ 101 /* Methods */ 102 void *(*lock_create)(void *context); 103 void (*rlock_acquire)(void *lock); 104 void (*wlock_acquire)(void *lock); 105 void (*rlock_release)(void *lock); 106 void (*wlock_release)(void *lock); 107 void (*lock_destroy)(void *lock); 108 void (*context_destroy)(void *context); 109 } LockInfo; 110 111 typedef struct Struct_Ver_Entry { 112 Elf_Word hash; 113 unsigned int flags; 114 const char *name; 115 const char *file; 116 } Ver_Entry; 117 118 typedef struct Struct_Sym_Match_Result { 119 const Elf_Sym *sym_out; 120 const Elf_Sym *vsymp; 121 int vcount; 122 } Sym_Match_Result; 123 124 #define VER_INFO_HIDDEN 0x01 125 126 /* 127 * Shared object descriptor. 128 * 129 * Items marked with "(%)" are dynamically allocated, and must be freed 130 * when the structure is destroyed. 131 * 132 * CAUTION: It appears that the JDK port peeks into these structures. 133 * It looks at "next" and "mapbase" at least. Don't add new members 134 * near the front, until this can be straightened out. 135 */ 136 typedef struct Struct_Obj_Entry { 137 /* 138 * These two items have to be set right for compatibility with the 139 * original ElfKit crt1.o. 140 */ 141 Elf_Size magic; /* Magic number (sanity check) */ 142 Elf_Size version; /* Version number of struct format */ 143 144 struct Struct_Obj_Entry *next; 145 char *path; /* Pathname of underlying file (%) */ 146 char *origin_path; /* Directory path of origin file */ 147 int refcount; 148 int dl_refcount; /* Number of times loaded by dlopen */ 149 150 /* These items are computed by map_object() or by digest_phdr(). */ 151 caddr_t mapbase; /* Base address of mapped region */ 152 size_t mapsize; /* Size of mapped region in bytes */ 153 size_t textsize; /* Size of text segment in bytes */ 154 Elf_Addr vaddrbase; /* Base address in shared object file */ 155 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 156 const Elf_Dyn *dynamic; /* Dynamic section */ 157 caddr_t entry; /* Entry point */ 158 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 159 size_t phsize; /* Size of program header in bytes */ 160 const char *interp; /* Pathname of the interpreter, if any */ 161 caddr_t relro_page; /* Address of first page of read-only data */ 162 size_t relro_size; /* Size of relro page(s) in bytes */ 163 Elf_Word stack_flags; 164 165 /* TLS information */ 166 int tlsindex; /* Index in DTV for this module */ 167 void *tlsinit; /* Base address of TLS init block */ 168 size_t tlsinitsize; /* Size of TLS init block for this module */ 169 size_t tlssize; /* Size of TLS block for this module */ 170 size_t tlsoffset; /* Offset of static TLS block for this module */ 171 size_t tlsalign; /* Alignment of static TLS block */ 172 173 /* Items from the dynamic section. */ 174 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 175 const Elf_Rel *rel; /* Relocation entries */ 176 unsigned long relsize; /* Size in bytes of relocation info */ 177 const Elf_Rela *rela; /* Relocation entries with addend */ 178 unsigned long relasize; /* Size in bytes of addend relocation info */ 179 const Elf_Rel *pltrel; /* PLT relocation entries */ 180 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 181 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 182 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 183 const Elf_Sym *symtab; /* Symbol table */ 184 const char *strtab; /* String table */ 185 unsigned long strsize; /* Size in bytes of string table */ 186 187 const Elf_Verneed *verneed; /* Required versions. */ 188 Elf_Word verneednum; /* Number of entries in verneed table */ 189 const Elf_Verdef *verdef; /* Provided versions. */ 190 Elf_Word verdefnum; /* Number of entries in verdef table */ 191 const Elf_Versym *versyms; /* Symbol versions table */ 192 193 const Elf_Hashelt *buckets; /* Hash table buckets array */ 194 unsigned long nbuckets; /* Number of buckets */ 195 const Elf_Hashelt *chains; /* Hash table chain array */ 196 unsigned long nchains; /* Number of entries in chain array */ 197 198 Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/ 199 Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */ 200 Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */ 201 Elf32_Word shift2_gnu; /* Bloom filter shift count */ 202 Elf32_Word dynsymcount; /* Total entries in dynsym table */ 203 Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */ 204 const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */ 205 const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */ 206 207 char *rpath; /* Search path specified in object */ 208 char *runpath; /* Search path with different priority */ 209 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 210 Needed_Entry *needed_filtees; 211 Needed_Entry *needed_aux_filtees; 212 213 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 214 know about. */ 215 Ver_Entry *vertab; /* Versions required /defined by this object */ 216 int vernum; /* Number of entries in vertab */ 217 218 Elf_Addr init; /* Initialization function to call */ 219 Elf_Addr fini; /* Termination function to call */ 220 Elf_Addr preinit_array; /* Pre-initialization array of functions */ 221 Elf_Addr init_array; /* Initialization array of functions */ 222 Elf_Addr fini_array; /* Termination array of functions */ 223 int preinit_array_num; /* Number of entries in preinit_array */ 224 int init_array_num; /* Number of entries in init_array */ 225 int fini_array_num; /* Number of entries in fini_array */ 226 227 int32_t osrel; /* OSREL note value */ 228 229 bool mainprog : 1; /* True if this is the main program */ 230 bool rtld : 1; /* True if this is the dynamic linker */ 231 bool relocated : 1; /* True if processed by relocate_objects() */ 232 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */ 233 bool textrel : 1; /* True if there are relocations to text seg */ 234 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 235 bool bind_now : 1; /* True if all relocations should be made first */ 236 bool traced : 1; /* Already printed in ldd trace output */ 237 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 238 bool init_done : 1; /* Already have added object to init list */ 239 bool tls_done : 1; /* Already allocated offset for static TLS */ 240 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 241 bool z_origin : 1; /* Process rpath and soname tokens */ 242 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 243 bool z_noopen : 1; /* Do not load on dlopen */ 244 bool z_loadfltr : 1; /* Immediately load filtees */ 245 bool z_interpose : 1; /* Interpose all objects but main */ 246 bool z_nodeflib : 1; /* Don't search default /usr/lib path */ 247 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 248 bool init_scanned: 1; /* Object is already on init list. */ 249 bool on_fini_list: 1; /* Object is already on fini list. */ 250 bool dag_inited : 1; /* Object has its DAG initialized. */ 251 bool filtees_loaded : 1; /* Filtees loaded */ 252 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 253 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 254 bool crt_no_init : 1; /* Object's crt does not call _init/_fini */ 255 bool note_present : 1; /* True if at least one PT_NOTE header found */ 256 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */ 257 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */ 258 259 struct link_map linkmap; /* For GDB and dlinfo() */ 260 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 261 Objlist dagmembers; /* DAG has these members (%) */ 262 dev_t dev; /* Object's filesystem's device */ 263 ino_t ino; /* Object's inode number */ 264 void *priv; /* Platform-dependent */ 265 } Obj_Entry; 266 267 #define RTLD_MAGIC 0xd550b87a 268 #define RTLD_VERSION 1 269 270 #define RTLD_FUNCTRACE "_rtld_functrace" 271 272 /* Flags to be passed into symlook_ family of functions. */ 273 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 274 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 275 dlsym. */ 276 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */ 277 278 /* Flags for load_object(). */ 279 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 280 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 281 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 282 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 283 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 284 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the 285 initialization during the image start. */ 286 287 /* 288 * Symbol cache entry used during relocation to avoid multiple lookups 289 * of the same symbol. 290 */ 291 typedef struct Struct_SymCache { 292 const Elf_Sym *sym; /* Symbol table entry */ 293 const Obj_Entry *obj; /* Shared object which defines it */ 294 } SymCache; 295 296 /* 297 * This structure provides a reentrant way to keep a list of objects and 298 * check which ones have already been processed in some way. 299 */ 300 typedef struct Struct_DoneList { 301 const Obj_Entry **objs; /* Array of object pointers */ 302 unsigned int num_alloc; /* Allocated size of the array */ 303 unsigned int num_used; /* Number of array slots used */ 304 } DoneList; 305 306 struct Struct_RtldLockState { 307 int lockstate; 308 sigjmp_buf env; 309 }; 310 311 struct fill_search_info_args { 312 int request; 313 unsigned int flags; 314 struct dl_serinfo *serinfo; 315 struct dl_serpath *serpath; 316 char *strspace; 317 }; 318 319 /* 320 * The pack of arguments and results for the symbol lookup functions. 321 */ 322 typedef struct Struct_SymLook { 323 const char *name; 324 unsigned long hash; 325 uint_fast32_t hash_gnu; 326 const Ver_Entry *ventry; 327 int flags; 328 const Obj_Entry *defobj_out; 329 const Elf_Sym *sym_out; 330 struct Struct_RtldLockState *lockstate; 331 } SymLook; 332 333 void _rtld_error(const char *, ...) __printflike(1, 2); 334 const char *rtld_strerror(int); 335 Obj_Entry *map_object(int, const char *, const struct stat *); 336 void *xcalloc(size_t, size_t); 337 void *xmalloc(size_t); 338 char *xstrdup(const char *); 339 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 340 341 void dump_relocations(Obj_Entry *); 342 void dump_obj_relocations(Obj_Entry *); 343 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 344 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 345 346 /* 347 * Function declarations. 348 */ 349 const char *basename(const char *); 350 unsigned long elf_hash(const char *); 351 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 352 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 353 void init_pltgot(Obj_Entry *); 354 void lockdflt_init(void); 355 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); 356 void obj_free(Obj_Entry *); 357 Obj_Entry *obj_new(void); 358 void _rtld_bind_start(void); 359 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 360 void symlook_init(SymLook *, const char *); 361 int symlook_obj(SymLook *, const Obj_Entry *); 362 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 363 struct tls_tcb *allocate_tls(Obj_Entry *); 364 void free_tls(struct tls_tcb *); 365 void *allocate_module_tls(int index); 366 bool allocate_tls_offset(Obj_Entry *obj); 367 void free_tls_offset(Obj_Entry *obj); 368 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 369 370 /* 371 * MD function declarations. 372 */ 373 int do_copy_relocations(Obj_Entry *); 374 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags, 375 struct Struct_RtldLockState *); 376 int reloc_plt(Obj_Entry *); 377 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *); 378 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 379 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *); 380 void allocate_initial_tls(Obj_Entry *); 381 382 #endif /* } */ 383