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 #ifdef COMPAT_32BIT 45 #undef STANDARD_LIBRARY_PATH 46 #undef _PATH_ELF_HINTS 47 #define _PATH_ELF_HINTS "/var/run/ld-elf32.so.hints" 48 /* For running 32 bit binaries */ 49 #define STANDARD_LIBRARY_PATH "/lib32:/usr/lib32" 50 #define LD_ "LD_32_" 51 #endif 52 53 #ifndef STANDARD_LIBRARY_PATH 54 #define STANDARD_LIBRARY_PATH "/lib:/usr/lib" 55 #endif 56 #ifndef LD_ 57 #define LD_ "LD_" 58 #endif 59 60 #define NEW(type) ((type *) xmalloc(sizeof(type))) 61 #define CNEW(type) ((type *) xcalloc(1, sizeof(type))) 62 63 /* We might as well do booleans like C++. */ 64 typedef unsigned char bool; 65 #define false 0 66 #define true 1 67 68 extern size_t tls_last_offset; 69 extern size_t tls_last_size; 70 extern size_t tls_static_space; 71 extern int tls_dtv_generation; 72 extern int tls_max_index; 73 74 extern int npagesizes; 75 extern size_t *pagesizes; 76 77 extern int main_argc; 78 extern char **main_argv; 79 extern char **environ; 80 81 struct stat; 82 struct Struct_Obj_Entry; 83 84 /* Lists of shared objects */ 85 typedef struct Struct_Objlist_Entry { 86 STAILQ_ENTRY(Struct_Objlist_Entry) link; 87 struct Struct_Obj_Entry *obj; 88 } Objlist_Entry; 89 90 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 91 92 /* Types of init and fini functions */ 93 typedef void (*InitFunc)(void); 94 typedef void (*InitArrFunc)(int, char **, char **); 95 96 /* Lists of shared object dependencies */ 97 typedef struct Struct_Needed_Entry { 98 struct Struct_Needed_Entry *next; 99 struct Struct_Obj_Entry *obj; 100 unsigned long name; /* Offset of name in string table */ 101 } Needed_Entry; 102 103 typedef struct Struct_Name_Entry { 104 STAILQ_ENTRY(Struct_Name_Entry) link; 105 char name[1]; 106 } Name_Entry; 107 108 /* Lock object */ 109 typedef struct Struct_LockInfo { 110 void *context; /* Client context for creating locks */ 111 void *thelock; /* The one big lock */ 112 /* Debugging aids. */ 113 volatile int rcount; /* Number of readers holding lock */ 114 volatile int wcount; /* Number of writers holding lock */ 115 /* Methods */ 116 void *(*lock_create)(void *context); 117 void (*rlock_acquire)(void *lock); 118 void (*wlock_acquire)(void *lock); 119 void (*rlock_release)(void *lock); 120 void (*wlock_release)(void *lock); 121 void (*lock_destroy)(void *lock); 122 void (*context_destroy)(void *context); 123 } LockInfo; 124 125 typedef struct Struct_Ver_Entry { 126 Elf_Word hash; 127 unsigned int flags; 128 const char *name; 129 const char *file; 130 } Ver_Entry; 131 132 typedef struct Struct_Sym_Match_Result { 133 const Elf_Sym *sym_out; 134 const Elf_Sym *vsymp; 135 int vcount; 136 } Sym_Match_Result; 137 138 #define VER_INFO_HIDDEN 0x01 139 140 /* 141 * Shared object descriptor. 142 * 143 * Items marked with "(%)" are dynamically allocated, and must be freed 144 * when the structure is destroyed. 145 * 146 * CAUTION: It appears that the JDK port peeks into these structures. 147 * It looks at "next" and "mapbase" at least. Don't add new members 148 * near the front, until this can be straightened out. 149 */ 150 typedef struct Struct_Obj_Entry { 151 /* 152 * These two items have to be set right for compatibility with the 153 * original ElfKit crt1.o. 154 */ 155 Elf_Size magic; /* Magic number (sanity check) */ 156 Elf_Size version; /* Version number of struct format */ 157 158 struct Struct_Obj_Entry *next; 159 char *path; /* Pathname of underlying file (%) */ 160 char *origin_path; /* Directory path of origin file */ 161 int refcount; 162 int dl_refcount; /* Number of times loaded by dlopen */ 163 164 /* These items are computed by map_object() or by digest_phdr(). */ 165 caddr_t mapbase; /* Base address of mapped region */ 166 size_t mapsize; /* Size of mapped region in bytes */ 167 size_t textsize; /* Size of text segment in bytes */ 168 Elf_Addr vaddrbase; /* Base address in shared object file */ 169 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 170 const Elf_Dyn *dynamic; /* Dynamic section */ 171 caddr_t entry; /* Entry point */ 172 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 173 size_t phsize; /* Size of program header in bytes */ 174 const char *interp; /* Pathname of the interpreter, if any */ 175 Elf_Word stack_flags; 176 177 /* TLS information */ 178 int tlsindex; /* Index in DTV for this module */ 179 void *tlsinit; /* Base address of TLS init block */ 180 size_t tlsinitsize; /* Size of TLS init block for this module */ 181 size_t tlssize; /* Size of TLS block for this module */ 182 size_t tlsoffset; /* Offset of static TLS block for this module */ 183 size_t tlsalign; /* Alignment of static TLS block */ 184 185 caddr_t relro_page; 186 size_t relro_size; 187 188 /* Items from the dynamic section. */ 189 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 190 const Elf_Rel *rel; /* Relocation entries */ 191 unsigned long relsize; /* Size in bytes of relocation info */ 192 const Elf_Rela *rela; /* Relocation entries with addend */ 193 unsigned long relasize; /* Size in bytes of addend relocation info */ 194 const Elf_Rel *pltrel; /* PLT relocation entries */ 195 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 196 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 197 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 198 const Elf_Sym *symtab; /* Symbol table */ 199 const char *strtab; /* String table */ 200 unsigned long strsize; /* Size in bytes of string table */ 201 #ifdef __mips__ 202 Elf_Word local_gotno; /* Number of local GOT entries */ 203 Elf_Word symtabno; /* Number of dynamic symbols */ 204 Elf_Word gotsym; /* First dynamic symbol in GOT */ 205 #endif 206 207 const Elf_Verneed *verneed; /* Required versions. */ 208 Elf_Word verneednum; /* Number of entries in verneed table */ 209 const Elf_Verdef *verdef; /* Provided versions. */ 210 Elf_Word verdefnum; /* Number of entries in verdef table */ 211 const Elf_Versym *versyms; /* Symbol versions table */ 212 213 const Elf_Hashelt *buckets; /* Hash table buckets array */ 214 unsigned long nbuckets; /* Number of buckets */ 215 const Elf_Hashelt *chains; /* Hash table chain array */ 216 unsigned long nchains; /* Number of entries in chain array */ 217 218 Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/ 219 Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */ 220 Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */ 221 Elf32_Word shift2_gnu; /* Bloom filter shift count */ 222 Elf32_Word dynsymcount; /* Total entries in dynsym table */ 223 Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */ 224 const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */ 225 const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */ 226 227 char *rpath; /* Search path specified in object */ 228 char *runpath; /* Search path with different priority */ 229 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 230 Needed_Entry *needed_filtees; 231 Needed_Entry *needed_aux_filtees; 232 233 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 234 know about. */ 235 Ver_Entry *vertab; /* Versions required /defined by this object */ 236 int vernum; /* Number of entries in vertab */ 237 238 Elf_Addr init; /* Initialization function to call */ 239 Elf_Addr fini; /* Termination function to call */ 240 Elf_Addr preinit_array; /* Pre-initialization array of functions */ 241 Elf_Addr init_array; /* Initialization array of functions */ 242 Elf_Addr fini_array; /* Termination array of functions */ 243 int preinit_array_num; /* Number of entries in preinit_array */ 244 int init_array_num; /* Number of entries in init_array */ 245 int fini_array_num; /* Number of entries in fini_array */ 246 247 int32_t osrel; /* OSREL note value */ 248 249 bool mainprog : 1; /* True if this is the main program */ 250 bool rtld : 1; /* True if this is the dynamic linker */ 251 bool relocated : 1; /* True if processed by relocate_objects() */ 252 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */ 253 bool textrel : 1; /* True if there are relocations to text seg */ 254 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 255 bool bind_now : 1; /* True if all relocations should be made first */ 256 bool traced : 1; /* Already printed in ldd trace output */ 257 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 258 bool init_done : 1; /* Already have added object to init list */ 259 bool tls_done : 1; /* Already allocated offset for static TLS */ 260 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 261 bool z_origin : 1; /* Process rpath and soname tokens */ 262 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 263 bool z_noopen : 1; /* Do not load on dlopen */ 264 bool z_loadfltr : 1; /* Immediately load filtees */ 265 bool z_interpose : 1; /* Interpose all objects but main */ 266 bool z_nodeflib : 1; /* Don't search default library path */ 267 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 268 bool init_scanned: 1; /* Object is already on init list. */ 269 bool on_fini_list: 1; /* Object is already on fini list. */ 270 bool dag_inited : 1; /* Object has its DAG initialized. */ 271 bool filtees_loaded : 1; /* Filtees loaded */ 272 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 273 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 274 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */ 275 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */ 276 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */ 277 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */ 278 bool dlopened : 1; /* dlopen()-ed (vs. load statically) */ 279 280 struct link_map linkmap; /* For GDB and dlinfo() */ 281 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 282 Objlist dagmembers; /* DAG has these members (%) */ 283 dev_t dev; /* Object's filesystem's device */ 284 ino_t ino; /* Object's inode number */ 285 void *priv; /* Platform-dependent */ 286 } Obj_Entry; 287 288 #define RTLD_MAGIC 0xd550b87a 289 #define RTLD_VERSION 1 290 291 #define RTLD_STATIC_TLS_EXTRA 128 292 293 /* Flags to be passed into symlook_ family of functions. */ 294 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 295 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 296 dlsym. */ 297 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */ 298 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in 299 reloc_non_plt(). */ 300 301 /* Flags for load_object(). */ 302 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 303 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 304 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 305 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 306 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 307 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the 308 initialization during the image start. */ 309 310 /* 311 * Symbol cache entry used during relocation to avoid multiple lookups 312 * of the same symbol. 313 */ 314 typedef struct Struct_SymCache { 315 const Elf_Sym *sym; /* Symbol table entry */ 316 const Obj_Entry *obj; /* Shared object which defines it */ 317 } SymCache; 318 319 /* 320 * This structure provides a reentrant way to keep a list of objects and 321 * check which ones have already been processed in some way. 322 */ 323 typedef struct Struct_DoneList { 324 const Obj_Entry **objs; /* Array of object pointers */ 325 unsigned int num_alloc; /* Allocated size of the array */ 326 unsigned int num_used; /* Number of array slots used */ 327 } DoneList; 328 329 struct Struct_RtldLockState { 330 int lockstate; 331 sigjmp_buf env; 332 }; 333 334 struct fill_search_info_args { 335 int request; 336 unsigned int flags; 337 struct dl_serinfo *serinfo; 338 struct dl_serpath *serpath; 339 char *strspace; 340 }; 341 342 /* 343 * The pack of arguments and results for the symbol lookup functions. 344 */ 345 typedef struct Struct_SymLook { 346 const char *name; 347 unsigned long hash; 348 uint32_t hash_gnu; 349 const Ver_Entry *ventry; 350 int flags; 351 const Obj_Entry *defobj_out; 352 const Elf_Sym *sym_out; 353 struct Struct_RtldLockState *lockstate; 354 } SymLook; 355 356 void _rtld_error(const char *, ...) __printflike(1, 2); 357 const char *rtld_strerror(int); 358 Obj_Entry *map_object(int, const char *, const struct stat *); 359 void *xcalloc(size_t, size_t); 360 void *xmalloc(size_t); 361 char *xstrdup(const char *); 362 void *malloc_aligned(size_t size, size_t align); 363 void free_aligned(void *ptr); 364 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 365 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 366 367 void dump_relocations(Obj_Entry *); 368 void dump_obj_relocations(Obj_Entry *); 369 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 370 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 371 372 /* 373 * Function declarations. 374 */ 375 unsigned long elf_hash(const char *); 376 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 377 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 378 void init_pltgot(Obj_Entry *); 379 void lockdflt_init(void); 380 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); 381 void obj_free(Obj_Entry *); 382 Obj_Entry *obj_new(void); 383 void _rtld_bind_start(void); 384 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 385 void symlook_init(SymLook *, const char *); 386 int symlook_obj(SymLook *, const Obj_Entry *); 387 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 388 void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 389 void free_tls(void *, size_t, size_t); 390 void *allocate_module_tls(int index); 391 bool allocate_tls_offset(Obj_Entry *obj); 392 void free_tls_offset(Obj_Entry *obj); 393 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 394 395 /* 396 * MD function declarations. 397 */ 398 int do_copy_relocations(Obj_Entry *); 399 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags, 400 struct Struct_RtldLockState *); 401 int reloc_plt(Obj_Entry *); 402 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *); 403 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 404 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *); 405 void allocate_initial_tls(Obj_Entry *); 406 407 #endif /* } */ 408