1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 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 <stdbool.h> 39 #include <setjmp.h> 40 #include <stddef.h> 41 42 #include "rtld_lock.h" 43 #include "rtld_machdep.h" 44 45 #define NEW(type) ((type *) xmalloc(sizeof(type))) 46 #define CNEW(type) ((type *) xcalloc(1, sizeof(type))) 47 48 extern size_t tls_last_offset; 49 extern size_t tls_last_size; 50 extern size_t tls_static_space; 51 extern Elf_Addr tls_dtv_generation; 52 extern int tls_max_index; 53 54 extern int npagesizes; 55 extern size_t *pagesizes; 56 extern size_t page_size; 57 58 extern int main_argc; 59 extern char **main_argv; 60 extern char **environ; 61 62 struct stat; 63 struct Struct_Obj_Entry; 64 65 /* Lists of shared objects */ 66 typedef struct Struct_Objlist_Entry { 67 STAILQ_ENTRY(Struct_Objlist_Entry) link; 68 struct Struct_Obj_Entry *obj; 69 } Objlist_Entry; 70 71 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 72 73 /* Types of init and fini functions */ 74 typedef void (*InitFunc)(void); 75 typedef void (*InitArrFunc)(int, char **, char **); 76 77 /* Lists of shared object dependencies */ 78 typedef struct Struct_Needed_Entry { 79 struct Struct_Needed_Entry *next; 80 struct Struct_Obj_Entry *obj; 81 unsigned long name; /* Offset of name in string table */ 82 } Needed_Entry; 83 84 typedef struct Struct_Name_Entry { 85 STAILQ_ENTRY(Struct_Name_Entry) link; 86 char name[1]; 87 } Name_Entry; 88 89 /* Lock object */ 90 typedef struct Struct_LockInfo { 91 void *context; /* Client context for creating locks */ 92 void *thelock; /* The one big lock */ 93 /* Debugging aids. */ 94 volatile int rcount; /* Number of readers holding lock */ 95 volatile int wcount; /* Number of writers holding lock */ 96 /* Methods */ 97 void *(*lock_create)(void *context); 98 void (*rlock_acquire)(void *lock); 99 void (*wlock_acquire)(void *lock); 100 void (*rlock_release)(void *lock); 101 void (*wlock_release)(void *lock); 102 void (*lock_destroy)(void *lock); 103 void (*context_destroy)(void *context); 104 } LockInfo; 105 106 typedef struct Struct_Ver_Entry { 107 Elf_Word hash; 108 unsigned int flags; 109 const char *name; 110 const char *file; 111 } Ver_Entry; 112 113 typedef struct Struct_Sym_Match_Result { 114 const Elf_Sym *sym_out; 115 const Elf_Sym *vsymp; 116 int vcount; 117 } Sym_Match_Result; 118 119 #define VER_INFO_HIDDEN 0x01 120 121 /* 122 * Shared object descriptor. 123 * 124 * Items marked with "(%)" are dynamically allocated, and must be freed 125 * when the structure is destroyed. 126 * 127 * CAUTION: It appears that the JDK port peeks into these structures. 128 * It looks at "next" and "mapbase" at least. Don't add new members 129 * near the front, until this can be straightened out. 130 */ 131 typedef struct Struct_Obj_Entry { 132 /* 133 * These two items have to be set right for compatibility with the 134 * original ElfKit crt1.o. 135 */ 136 Elf_Size magic; /* Magic number (sanity check) */ 137 Elf_Size version; /* Version number of struct format */ 138 139 TAILQ_ENTRY(Struct_Obj_Entry) next; 140 char *path; /* Pathname of underlying file (%) */ 141 char *origin_path; /* Directory path of origin file */ 142 int refcount; /* DAG references */ 143 int holdcount; /* Count of transient references */ 144 int dl_refcount; /* Number of times loaded by dlopen */ 145 146 /* These items are computed by map_object() or by digest_phdr(). */ 147 caddr_t mapbase; /* Base address of mapped region */ 148 size_t mapsize; /* Size of mapped region in bytes */ 149 Elf_Addr vaddrbase; /* Base address in shared object file */ 150 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 151 const Elf_Dyn *dynamic; /* Dynamic section */ 152 caddr_t entry; /* Entry point */ 153 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 154 size_t phsize; /* Size of program header in bytes */ 155 const char *interp; /* Pathname of the interpreter, if any */ 156 Elf_Word stack_flags; 157 158 /* TLS information */ 159 int tlsindex; /* Index in DTV for this module */ 160 void *tlsinit; /* Base address of TLS init block */ 161 size_t tlsinitsize; /* Size of TLS init block for this module */ 162 size_t tlssize; /* Size of TLS block for this module */ 163 size_t tlsoffset; /* Offset of static TLS block for this module */ 164 size_t tlsalign; /* Alignment of static TLS block */ 165 size_t tlspoffset; /* p_offset of the 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_Relr *relr; /* RELR relocation entries */ 177 unsigned long relrsize; /* Size in bytes of RELR relocations */ 178 const Elf_Rel *pltrel; /* PLT relocation entries */ 179 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 180 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 181 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 182 const Elf_Sym *symtab; /* Symbol table */ 183 const char *strtab; /* String table */ 184 unsigned long strsize; /* Size in bytes of string table */ 185 #ifdef __powerpc__ 186 #ifdef __powerpc64__ 187 Elf_Addr glink; /* GLINK PLT call stub section */ 188 #else 189 Elf_Addr *gotptr; /* GOT pointer (secure-plt only) */ 190 #endif 191 #endif 192 193 const Elf_Verneed *verneed; /* Required versions. */ 194 Elf_Word verneednum; /* Number of entries in verneed table */ 195 const Elf_Verdef *verdef; /* Provided versions. */ 196 Elf_Word verdefnum; /* Number of entries in verdef table */ 197 const Elf_Versym *versyms; /* Symbol versions table */ 198 199 const Elf_Hashelt *buckets; /* Hash table buckets array */ 200 unsigned long nbuckets; /* Number of buckets */ 201 const Elf_Hashelt *chains; /* Hash table chain array */ 202 unsigned long nchains; /* Number of entries in chain array */ 203 204 Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/ 205 Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */ 206 Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */ 207 Elf32_Word shift2_gnu; /* Bloom filter shift count */ 208 Elf32_Word dynsymcount; /* Total entries in dynsym table */ 209 const Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */ 210 const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */ 211 const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */ 212 213 const char *rpath; /* Search path specified in object */ 214 const char *runpath; /* Search path with different priority */ 215 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 216 Needed_Entry *needed_filtees; 217 Needed_Entry *needed_aux_filtees; 218 219 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 220 know about. */ 221 Ver_Entry *vertab; /* Versions required /defined by this object */ 222 int vernum; /* Number of entries in vertab */ 223 224 Elf_Addr init; /* Initialization function to call */ 225 Elf_Addr fini; /* Termination function to call */ 226 Elf_Addr preinit_array; /* Pre-initialization array of functions */ 227 Elf_Addr init_array; /* Initialization array of functions */ 228 Elf_Addr fini_array; /* Termination array of functions */ 229 int preinit_array_num; /* Number of entries in preinit_array */ 230 int init_array_num; /* Number of entries in init_array */ 231 int fini_array_num; /* Number of entries in fini_array */ 232 233 int32_t osrel; /* OSREL note value */ 234 uint32_t fctl0; /* FEATURE_CONTROL note desc[0] value */ 235 236 bool mainprog : 1; /* True if this is the main program */ 237 bool rtld : 1; /* True if this is the dynamic linker */ 238 bool relocated : 1; /* True if processed by relocate_objects() */ 239 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */ 240 bool textrel : 1; /* True if there are relocations to text seg */ 241 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 242 bool bind_now : 1; /* True if all relocations should be made first */ 243 bool traced : 1; /* Already printed in ldd trace output */ 244 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 245 bool init_done : 1; /* Already have added object to init list */ 246 bool tls_static : 1; /* Already allocated offset for static TLS */ 247 bool tls_dynamic : 1; /* A non-static DTV entry has been allocated */ 248 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 249 bool z_origin : 1; /* Process rpath and soname tokens */ 250 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 251 bool z_noopen : 1; /* Do not load on dlopen */ 252 bool z_loadfltr : 1; /* Immediately load filtees */ 253 bool z_interpose : 1; /* Interpose all objects but main */ 254 bool z_nodeflib : 1; /* Don't search default library path */ 255 bool z_global : 1; /* Make the object global */ 256 bool z_pie : 1; /* Object proclaimed itself PIE executable */ 257 bool static_tls : 1; /* Needs static TLS allocation */ 258 bool static_tls_copied : 1; /* Needs static TLS copying */ 259 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 260 bool init_scanned: 1; /* Object is already on init list. */ 261 bool on_fini_list: 1; /* Object is already on fini list. */ 262 bool dag_inited : 1; /* Object has its DAG initialized. */ 263 bool filtees_loaded : 1; /* Filtees loaded */ 264 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 265 bool irelative_nonplt : 1; /* Object has R_MACHDEP_IRELATIVE non-plt relocs */ 266 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 267 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */ 268 bool ifuncs_resolved : 1; /* Object ifuncs were already resolved */ 269 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */ 270 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */ 271 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */ 272 bool dlopened : 1; /* dlopen()-ed (vs. load statically) */ 273 bool marker : 1; /* marker on the global obj list */ 274 bool unholdfree : 1; /* unmap upon last unhold */ 275 bool doomed : 1; /* Object cannot be referenced */ 276 277 struct link_map linkmap; /* For GDB and dlinfo() */ 278 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 279 Objlist dagmembers; /* DAG has these members (%) */ 280 dev_t dev; /* Object's filesystem's device */ 281 ino_t ino; /* Object's inode number */ 282 void *priv; /* Platform-dependent */ 283 } Obj_Entry; 284 285 #define RTLD_MAGIC 0xd550b87a 286 #define RTLD_VERSION 1 287 288 TAILQ_HEAD(obj_entry_q, Struct_Obj_Entry); 289 290 #define RTLD_STATIC_TLS_EXTRA 128 291 292 /* Flags to be passed into symlook_ family of functions. */ 293 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 294 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 295 dlsym. */ 296 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */ 297 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in 298 reloc_non_plt(). */ 299 300 /* Flags for load_object(). */ 301 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 302 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 303 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 304 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 305 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 306 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the 307 initialization during the image start. */ 308 #define RTLD_LO_IGNSTLS 0x40 /* Do not allocate static TLS */ 309 #define RTLD_LO_DEEPBIND 0x80 /* Force symbolic for this object */ 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 *xmalloc_aligned(size_t size, size_t align, size_t offset); 365 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 366 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 367 extern bool ld_bind_not; 368 extern bool ld_fast_sigblock; 369 370 void dump_relocations(Obj_Entry *); 371 void dump_obj_relocations(Obj_Entry *); 372 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 373 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 374 375 /* 376 * Function declarations. 377 */ 378 uintptr_t rtld_round_page(uintptr_t); 379 uintptr_t rtld_trunc_page(uintptr_t); 380 Elf32_Word elf_hash(const char *); 381 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 382 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 383 void lockdflt_init(void); 384 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); 385 Obj_Entry *globallist_curr(const Obj_Entry *obj); 386 Obj_Entry *globallist_next(const Obj_Entry *obj); 387 void obj_free(Obj_Entry *); 388 Obj_Entry *obj_new(void); 389 Obj_Entry *obj_from_addr(const void *); 390 void _rtld_bind_start(void); 391 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 392 void symlook_init(SymLook *, const char *); 393 int symlook_obj(SymLook *, const Obj_Entry *); 394 void *tls_get_addr_common(uintptr_t **dtvp, int index, size_t offset); 395 void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 396 void free_tls(void *, size_t, size_t); 397 void *allocate_module_tls(int index); 398 bool allocate_tls_offset(Obj_Entry *obj); 399 void free_tls_offset(Obj_Entry *obj); 400 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 401 int convert_prot(int elfflags); 402 bool check_elf_headers(const Elf_Ehdr *hdr, const char *path); 403 404 /* 405 * MD function declarations. 406 */ 407 int do_copy_relocations(Obj_Entry *); 408 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags, 409 struct Struct_RtldLockState *); 410 int reloc_plt(Obj_Entry *, int flags, struct Struct_RtldLockState *); 411 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *); 412 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 413 int reloc_iresolve_nonplt(Obj_Entry *, struct Struct_RtldLockState *); 414 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *); 415 void ifunc_init(Elf_Auxinfo[__min_size(AT_COUNT)]); 416 void init_pltgot(Obj_Entry *); 417 void allocate_initial_tls(Obj_Entry *); 418 419 #endif /* } */ 420