1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright 1996, 1997, 1998, 1999, 2000 John D. Polstra. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 * 27 * $FreeBSD$ 28 */ 29 30 #ifndef RTLD_H /* { */ 31 #define RTLD_H 1 32 33 #include <machine/elf.h> 34 #include <sys/types.h> 35 #include <sys/queue.h> 36 37 #include <elf-hints.h> 38 #include <link.h> 39 #include <stdarg.h> 40 #include <stdbool.h> 41 #include <setjmp.h> 42 #include <stddef.h> 43 44 #include "rtld_lock.h" 45 #include "rtld_machdep.h" 46 47 #define NEW(type) ((type *) xmalloc(sizeof(type))) 48 #define CNEW(type) ((type *) xcalloc(1, sizeof(type))) 49 50 extern size_t tls_last_offset; 51 extern size_t tls_last_size; 52 extern size_t tls_static_space; 53 extern Elf_Addr tls_dtv_generation; 54 extern int tls_max_index; 55 56 extern int npagesizes; 57 extern size_t *pagesizes; 58 59 extern int main_argc; 60 extern char **main_argv; 61 extern char **environ; 62 63 struct stat; 64 struct Struct_Obj_Entry; 65 66 /* Lists of shared objects */ 67 typedef struct Struct_Objlist_Entry { 68 STAILQ_ENTRY(Struct_Objlist_Entry) link; 69 struct Struct_Obj_Entry *obj; 70 } Objlist_Entry; 71 72 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 73 74 /* Types of init and fini functions */ 75 typedef void (*InitFunc)(void); 76 typedef void (*InitArrFunc)(int, char **, char **); 77 78 /* Lists of shared object dependencies */ 79 typedef struct Struct_Needed_Entry { 80 struct Struct_Needed_Entry *next; 81 struct Struct_Obj_Entry *obj; 82 unsigned long name; /* Offset of name in string table */ 83 } Needed_Entry; 84 85 typedef struct Struct_Name_Entry { 86 STAILQ_ENTRY(Struct_Name_Entry) link; 87 char name[1]; 88 } Name_Entry; 89 90 /* Lock object */ 91 typedef struct Struct_LockInfo { 92 void *context; /* Client context for creating locks */ 93 void *thelock; /* The one big lock */ 94 /* Debugging aids. */ 95 volatile int rcount; /* Number of readers holding lock */ 96 volatile int wcount; /* Number of writers holding lock */ 97 /* Methods */ 98 void *(*lock_create)(void *context); 99 void (*rlock_acquire)(void *lock); 100 void (*wlock_acquire)(void *lock); 101 void (*rlock_release)(void *lock); 102 void (*wlock_release)(void *lock); 103 void (*lock_destroy)(void *lock); 104 void (*context_destroy)(void *context); 105 } LockInfo; 106 107 typedef struct Struct_Ver_Entry { 108 Elf_Word hash; 109 unsigned int flags; 110 const char *name; 111 const char *file; 112 } Ver_Entry; 113 114 typedef struct Struct_Sym_Match_Result { 115 const Elf_Sym *sym_out; 116 const Elf_Sym *vsymp; 117 int vcount; 118 } Sym_Match_Result; 119 120 #define VER_INFO_HIDDEN 0x01 121 122 /* 123 * Shared object descriptor. 124 * 125 * Items marked with "(%)" are dynamically allocated, and must be freed 126 * when the structure is destroyed. 127 * 128 * CAUTION: It appears that the JDK port peeks into these structures. 129 * It looks at "next" and "mapbase" at least. Don't add new members 130 * near the front, until this can be straightened out. 131 */ 132 typedef struct Struct_Obj_Entry { 133 /* 134 * These two items have to be set right for compatibility with the 135 * original ElfKit crt1.o. 136 */ 137 Elf_Size magic; /* Magic number (sanity check) */ 138 Elf_Size version; /* Version number of struct format */ 139 140 TAILQ_ENTRY(Struct_Obj_Entry) next; 141 char *path; /* Pathname of underlying file (%) */ 142 char *origin_path; /* Directory path of origin file */ 143 int refcount; /* DAG references */ 144 int holdcount; /* Count of transient references */ 145 int dl_refcount; /* Number of times loaded by dlopen */ 146 147 /* These items are computed by map_object() or by digest_phdr(). */ 148 caddr_t mapbase; /* Base address of mapped region */ 149 size_t mapsize; /* Size of mapped region in bytes */ 150 Elf_Addr vaddrbase; /* Base address in shared object file */ 151 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 152 const Elf_Dyn *dynamic; /* Dynamic section */ 153 caddr_t entry; /* Entry point */ 154 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 155 size_t phsize; /* Size of program header in bytes */ 156 const char *interp; /* Pathname of the interpreter, if any */ 157 Elf_Word stack_flags; 158 159 /* TLS information */ 160 int tlsindex; /* Index in DTV for this module */ 161 void *tlsinit; /* Base address of TLS init block */ 162 size_t tlsinitsize; /* Size of TLS init block for this module */ 163 size_t tlssize; /* Size of TLS block for this module */ 164 size_t tlsoffset; /* Offset of static TLS block for this module */ 165 size_t tlsalign; /* Alignment of static TLS block */ 166 167 caddr_t relro_page; 168 size_t relro_size; 169 170 /* Items from the dynamic section. */ 171 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 172 const Elf_Rel *rel; /* Relocation entries */ 173 unsigned long relsize; /* Size in bytes of relocation info */ 174 const Elf_Rela *rela; /* Relocation entries with addend */ 175 unsigned long relasize; /* Size in bytes of addend relocation info */ 176 const Elf_Rel *pltrel; /* PLT relocation entries */ 177 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 178 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 179 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 180 const Elf_Sym *symtab; /* Symbol table */ 181 const char *strtab; /* String table */ 182 unsigned long strsize; /* Size in bytes of string table */ 183 #ifdef __mips__ 184 Elf_Word local_gotno; /* Number of local GOT entries */ 185 Elf_Word symtabno; /* Number of dynamic symbols */ 186 Elf_Word gotsym; /* First dynamic symbol in GOT */ 187 Elf_Addr *mips_pltgot; /* Second PLT GOT */ 188 #endif 189 #ifdef __powerpc__ 190 #ifdef __powerpc64__ 191 Elf_Addr glink; /* GLINK PLT call stub section */ 192 #else 193 Elf_Addr *gotptr; /* GOT pointer (secure-plt only) */ 194 #endif 195 #endif 196 197 const Elf_Verneed *verneed; /* Required versions. */ 198 Elf_Word verneednum; /* Number of entries in verneed table */ 199 const Elf_Verdef *verdef; /* Provided versions. */ 200 Elf_Word verdefnum; /* Number of entries in verdef table */ 201 const Elf_Versym *versyms; /* Symbol versions table */ 202 203 const Elf_Hashelt *buckets; /* Hash table buckets array */ 204 unsigned long nbuckets; /* Number of buckets */ 205 const Elf_Hashelt *chains; /* Hash table chain array */ 206 unsigned long nchains; /* Number of entries in chain array */ 207 208 Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/ 209 Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */ 210 Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */ 211 Elf32_Word shift2_gnu; /* Bloom filter shift count */ 212 Elf32_Word dynsymcount; /* Total entries in dynsym table */ 213 const Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */ 214 const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */ 215 const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */ 216 217 const char *rpath; /* Search path specified in object */ 218 const char *runpath; /* Search path with different priority */ 219 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 220 Needed_Entry *needed_filtees; 221 Needed_Entry *needed_aux_filtees; 222 223 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 224 know about. */ 225 Ver_Entry *vertab; /* Versions required /defined by this object */ 226 int vernum; /* Number of entries in vertab */ 227 228 Elf_Addr init; /* Initialization function to call */ 229 Elf_Addr fini; /* Termination function to call */ 230 Elf_Addr preinit_array; /* Pre-initialization array of functions */ 231 Elf_Addr init_array; /* Initialization array of functions */ 232 Elf_Addr fini_array; /* Termination array of functions */ 233 int preinit_array_num; /* Number of entries in preinit_array */ 234 int init_array_num; /* Number of entries in init_array */ 235 int fini_array_num; /* Number of entries in fini_array */ 236 237 int32_t osrel; /* OSREL note value */ 238 uint32_t fctl0; /* FEATURE_CONTROL note desc[0] value */ 239 240 bool mainprog : 1; /* True if this is the main program */ 241 bool rtld : 1; /* True if this is the dynamic linker */ 242 bool relocated : 1; /* True if processed by relocate_objects() */ 243 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */ 244 bool textrel : 1; /* True if there are relocations to text seg */ 245 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 246 bool bind_now : 1; /* True if all relocations should be made first */ 247 bool traced : 1; /* Already printed in ldd trace output */ 248 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 249 bool init_done : 1; /* Already have added object to init list */ 250 bool tls_done : 1; /* Already allocated offset for static TLS */ 251 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 252 bool z_origin : 1; /* Process rpath and soname tokens */ 253 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 254 bool z_noopen : 1; /* Do not load on dlopen */ 255 bool z_loadfltr : 1; /* Immediately load filtees */ 256 bool z_interpose : 1; /* Interpose all objects but main */ 257 bool z_nodeflib : 1; /* Don't search default library path */ 258 bool z_global : 1; /* Make the object global */ 259 bool static_tls : 1; /* Needs static TLS allocation */ 260 bool static_tls_copied : 1; /* Needs static TLS copying */ 261 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 262 bool init_scanned: 1; /* Object is already on init list. */ 263 bool on_fini_list: 1; /* Object is already on fini list. */ 264 bool dag_inited : 1; /* Object has its DAG initialized. */ 265 bool filtees_loaded : 1; /* Filtees loaded */ 266 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 267 bool irelative_nonplt : 1; /* Object has R_MACHDEP_IRELATIVE non-plt relocs */ 268 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 269 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */ 270 bool ifuncs_resolved : 1; /* Object ifuncs were already resolved */ 271 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */ 272 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */ 273 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */ 274 bool dlopened : 1; /* dlopen()-ed (vs. load statically) */ 275 bool marker : 1; /* marker on the global obj list */ 276 bool unholdfree : 1; /* unmap upon last unhold */ 277 bool doomed : 1; /* Object cannot be referenced */ 278 279 struct link_map linkmap; /* For GDB and dlinfo() */ 280 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 281 Objlist dagmembers; /* DAG has these members (%) */ 282 dev_t dev; /* Object's filesystem's device */ 283 ino_t ino; /* Object's inode number */ 284 void *priv; /* Platform-dependent */ 285 } Obj_Entry; 286 287 #define RTLD_MAGIC 0xd550b87a 288 #define RTLD_VERSION 1 289 290 TAILQ_HEAD(obj_entry_q, Struct_Obj_Entry); 291 292 #define RTLD_STATIC_TLS_EXTRA 128 293 294 /* Flags to be passed into symlook_ family of functions. */ 295 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 296 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 297 dlsym. */ 298 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */ 299 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in 300 reloc_non_plt(). */ 301 302 /* Flags for load_object(). */ 303 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 304 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 305 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 306 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 307 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 308 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the 309 initialization during the image start. */ 310 311 /* 312 * Symbol cache entry used during relocation to avoid multiple lookups 313 * of the same symbol. 314 */ 315 typedef struct Struct_SymCache { 316 const Elf_Sym *sym; /* Symbol table entry */ 317 const Obj_Entry *obj; /* Shared object which defines it */ 318 } SymCache; 319 320 /* 321 * This structure provides a reentrant way to keep a list of objects and 322 * check which ones have already been processed in some way. 323 */ 324 typedef struct Struct_DoneList { 325 const Obj_Entry **objs; /* Array of object pointers */ 326 unsigned int num_alloc; /* Allocated size of the array */ 327 unsigned int num_used; /* Number of array slots used */ 328 } DoneList; 329 330 struct Struct_RtldLockState { 331 int lockstate; 332 sigjmp_buf env; 333 }; 334 335 struct fill_search_info_args { 336 int request; 337 unsigned int flags; 338 struct dl_serinfo *serinfo; 339 struct dl_serpath *serpath; 340 char *strspace; 341 }; 342 343 /* 344 * The pack of arguments and results for the symbol lookup functions. 345 */ 346 typedef struct Struct_SymLook { 347 const char *name; 348 unsigned long hash; 349 uint32_t hash_gnu; 350 const Ver_Entry *ventry; 351 int flags; 352 const Obj_Entry *defobj_out; 353 const Elf_Sym *sym_out; 354 struct Struct_RtldLockState *lockstate; 355 } SymLook; 356 357 void _rtld_error(const char *, ...) __printflike(1, 2) __exported; 358 void rtld_die(void) __dead2; 359 const char *rtld_strerror(int); 360 Obj_Entry *map_object(int, const char *, const struct stat *); 361 void *xcalloc(size_t, size_t); 362 void *xmalloc(size_t); 363 char *xstrdup(const char *); 364 void *malloc_aligned(size_t size, size_t align); 365 void free_aligned(void *ptr); 366 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 367 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 368 extern bool ld_bind_not; 369 extern bool ld_fast_sigblock; 370 371 void dump_relocations(Obj_Entry *); 372 void dump_obj_relocations(Obj_Entry *); 373 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 374 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 375 376 /* 377 * Function declarations. 378 */ 379 unsigned long elf_hash(const char *); 380 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 381 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 382 void lockdflt_init(void); 383 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); 384 Obj_Entry *globallist_curr(const Obj_Entry *obj); 385 Obj_Entry *globallist_next(const Obj_Entry *obj); 386 void obj_free(Obj_Entry *); 387 Obj_Entry *obj_new(void); 388 void _rtld_bind_start(void); 389 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 390 void symlook_init(SymLook *, const char *); 391 int symlook_obj(SymLook *, const Obj_Entry *); 392 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 393 void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 394 void free_tls(void *, size_t, size_t); 395 void *allocate_module_tls(int index); 396 bool allocate_tls_offset(Obj_Entry *obj); 397 void free_tls_offset(Obj_Entry *obj); 398 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 399 int convert_prot(int elfflags); 400 401 /* 402 * MD function declarations. 403 */ 404 int do_copy_relocations(Obj_Entry *); 405 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags, 406 struct Struct_RtldLockState *); 407 int reloc_plt(Obj_Entry *, int flags, struct Struct_RtldLockState *); 408 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *); 409 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 410 int reloc_iresolve_nonplt(Obj_Entry *, struct Struct_RtldLockState *); 411 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *); 412 void ifunc_init(Elf_Auxinfo[__min_size(AT_COUNT)]); 413 void pre_init(void); 414 void init_pltgot(Obj_Entry *); 415 void allocate_initial_tls(Obj_Entry *); 416 417 void *__crt_calloc(size_t num, size_t size); 418 void __crt_free(void *cp); 419 void *__crt_malloc(size_t nbytes); 420 void *__crt_realloc(void *cp, size_t nbytes); 421 422 #endif /* } */ 423