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 extern size_t ld_static_tls_extra; 54 55 extern int npagesizes; 56 extern size_t *pagesizes; 57 extern size_t page_size; 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 size_t tlspoffset; /* p_offset of the static TLS block */ 167 168 caddr_t relro_page; 169 size_t relro_size; 170 171 /* Items from the dynamic section. */ 172 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 173 const Elf_Rel *rel; /* Relocation entries */ 174 unsigned long relsize; /* Size in bytes of relocation info */ 175 const Elf_Rela *rela; /* Relocation entries with addend */ 176 unsigned long relasize; /* Size in bytes of addend relocation info */ 177 const Elf_Relr *relr; /* RELR relocation entries */ 178 unsigned long relrsize; /* Size in bytes of RELR relocations */ 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 const 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 const char *rpath; /* Search path specified in object */ 208 const 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 uint32_t fctl0; /* FEATURE_CONTROL note desc[0] value */ 229 230 bool mainprog : 1; /* True if this is the main program */ 231 bool rtld : 1; /* True if this is the dynamic linker */ 232 bool relocated : 1; /* True if processed by relocate_objects() */ 233 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */ 234 bool textrel : 1; /* True if there are relocations to text seg */ 235 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 236 bool deepbind : 1; /* True if loaded with RTLD_DEEPBIND" */ 237 bool bind_now : 1; /* True if all relocations should be made first */ 238 bool traced : 1; /* Already printed in ldd trace output */ 239 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 240 bool init_done : 1; /* Already have added object to init list */ 241 bool tls_static : 1; /* Already allocated offset for static TLS */ 242 bool tls_dynamic : 1; /* A non-static DTV entry has been allocated */ 243 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 244 bool z_origin : 1; /* Process rpath and soname tokens */ 245 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 246 bool z_noopen : 1; /* Do not load on dlopen */ 247 bool z_loadfltr : 1; /* Immediately load filtees */ 248 bool z_interpose : 1; /* Interpose all objects but main */ 249 bool z_nodeflib : 1; /* Don't search default library path */ 250 bool z_global : 1; /* Make the object global */ 251 bool z_pie : 1; /* Object proclaimed itself PIE executable */ 252 bool static_tls : 1; /* Needs static TLS allocation */ 253 bool static_tls_copied : 1; /* Needs static TLS copying */ 254 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 255 bool init_scanned: 1; /* Object is already on init list. */ 256 bool on_fini_list: 1; /* Object is already on fini list. */ 257 bool dag_inited : 1; /* Object has its DAG initialized. */ 258 bool filtees_loaded : 1; /* Filtees loaded */ 259 bool filtees_loading : 1; /* In process of filtees loading */ 260 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 261 bool irelative_nonplt : 1; /* Object has R_MACHDEP_IRELATIVE non-plt relocs */ 262 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 263 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */ 264 bool ifuncs_resolved : 1; /* Object ifuncs were already resolved */ 265 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */ 266 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */ 267 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */ 268 bool dlopened : 1; /* dlopen()-ed (vs. load statically) */ 269 bool marker : 1; /* marker on the global obj list */ 270 bool unholdfree : 1; /* unmap upon last unhold */ 271 bool doomed : 1; /* Object cannot be referenced */ 272 273 MD_OBJ_ENTRY; 274 275 struct link_map linkmap; /* For GDB and dlinfo() */ 276 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 277 Objlist dagmembers; /* DAG has these members (%) */ 278 dev_t dev; /* Object's filesystem's device */ 279 ino_t ino; /* Object's inode number */ 280 void *priv; /* Platform-dependent */ 281 } Obj_Entry; 282 283 #define RTLD_MAGIC 0xd550b87a 284 #define RTLD_VERSION 1 285 286 TAILQ_HEAD(obj_entry_q, Struct_Obj_Entry); 287 288 #define RTLD_STATIC_TLS_EXTRA 128 289 290 /* Flags to be passed into symlook_ family of functions. */ 291 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 292 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 293 dlsym. */ 294 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */ 295 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in 296 reloc_non_plt(). */ 297 298 /* Flags for load_object(). */ 299 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 300 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 301 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 302 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 303 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 304 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the 305 initialization during the image start. */ 306 #define RTLD_LO_IGNSTLS 0x40 /* Do not allocate static TLS */ 307 #define RTLD_LO_DEEPBIND 0x80 /* Force symbolic for this object */ 308 309 /* 310 * Symbol cache entry used during relocation to avoid multiple lookups 311 * of the same symbol. 312 */ 313 typedef struct Struct_SymCache { 314 const Elf_Sym *sym; /* Symbol table entry */ 315 const Obj_Entry *obj; /* Shared object which defines it */ 316 } SymCache; 317 318 /* 319 * This structure provides a reentrant way to keep a list of objects and 320 * check which ones have already been processed in some way. 321 */ 322 typedef struct Struct_DoneList { 323 const Obj_Entry **objs; /* Array of object pointers */ 324 unsigned int num_alloc; /* Allocated size of the array */ 325 unsigned int num_used; /* Number of array slots used */ 326 } DoneList; 327 328 struct Struct_RtldLockState { 329 int lockstate; 330 sigjmp_buf env; 331 }; 332 333 struct fill_search_info_args { 334 int request; 335 unsigned int flags; 336 struct dl_serinfo *serinfo; 337 struct dl_serpath *serpath; 338 char *strspace; 339 }; 340 341 /* 342 * The pack of arguments and results for the symbol lookup functions. 343 */ 344 typedef struct Struct_SymLook { 345 const char *name; 346 unsigned long hash; 347 uint32_t hash_gnu; 348 const Ver_Entry *ventry; 349 int flags; 350 const Obj_Entry *defobj_out; 351 const Elf_Sym *sym_out; 352 struct Struct_RtldLockState *lockstate; 353 } SymLook; 354 355 void _rtld_error(const char *, ...) __printflike(1, 2) __exported; 356 void rtld_die(void) __dead2; 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 *xmalloc_aligned(size_t size, size_t align, size_t offset); 363 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 364 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 365 extern bool ld_bind_not; 366 extern bool ld_fast_sigblock; 367 368 void dump_relocations(Obj_Entry *); 369 void dump_obj_relocations(Obj_Entry *); 370 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 371 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 372 373 /* 374 * Function declarations. 375 */ 376 uintptr_t rtld_round_page(uintptr_t); 377 uintptr_t rtld_trunc_page(uintptr_t); 378 Elf32_Word elf_hash(const char *); 379 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 380 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 381 void lockdflt_init(void); 382 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); 383 Obj_Entry *globallist_curr(const Obj_Entry *obj); 384 Obj_Entry *globallist_next(const Obj_Entry *obj); 385 void obj_free(Obj_Entry *); 386 Obj_Entry *obj_new(void); 387 Obj_Entry *obj_from_addr(const 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(uintptr_t **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 bool check_elf_headers(const Elf_Ehdr *hdr, const char *path); 401 402 /* 403 * MD function declarations. 404 */ 405 int do_copy_relocations(Obj_Entry *); 406 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags, 407 struct Struct_RtldLockState *); 408 int reloc_plt(Obj_Entry *, int flags, struct Struct_RtldLockState *); 409 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *); 410 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 411 int reloc_iresolve_nonplt(Obj_Entry *, struct Struct_RtldLockState *); 412 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *); 413 void ifunc_init(Elf_Auxinfo[__min_size(AT_COUNT)]); 414 void init_pltgot(Obj_Entry *); 415 void allocate_initial_tls(Obj_Entry *); 416 417 #endif /* } */ 418