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 <setjmp.h> 41 #include <stddef.h> 42 43 #include "rtld_lock.h" 44 #include "rtld_machdep.h" 45 46 #define NEW(type) ((type *) xmalloc(sizeof(type))) 47 #define CNEW(type) ((type *) xcalloc(1, sizeof(type))) 48 49 /* We might as well do booleans like C++. */ 50 typedef unsigned char bool; 51 #define false 0 52 #define true 1 53 54 extern size_t tls_last_offset; 55 extern size_t tls_last_size; 56 extern size_t tls_static_space; 57 extern Elf_Addr tls_dtv_generation; 58 extern int tls_max_index; 59 60 extern int npagesizes; 61 extern size_t *pagesizes; 62 63 extern int main_argc; 64 extern char **main_argv; 65 extern char **environ; 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 TAILQ_ENTRY(Struct_Obj_Entry) next; 145 char *path; /* Pathname of underlying file (%) */ 146 char *origin_path; /* Directory path of origin file */ 147 int refcount; /* DAG references */ 148 int holdcount; /* Count of transient references */ 149 int dl_refcount; /* Number of times loaded by dlopen */ 150 151 /* These items are computed by map_object() or by digest_phdr(). */ 152 caddr_t mapbase; /* Base address of mapped region */ 153 size_t mapsize; /* Size of mapped region 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 Elf_Word stack_flags; 162 163 /* TLS information */ 164 int tlsindex; /* Index in DTV for this module */ 165 void *tlsinit; /* Base address of TLS init block */ 166 size_t tlsinitsize; /* Size of TLS init block for this module */ 167 size_t tlssize; /* Size of TLS block for this module */ 168 size_t tlsoffset; /* Offset of static TLS block for this module */ 169 size_t tlsalign; /* Alignment of static TLS block */ 170 171 caddr_t relro_page; 172 size_t relro_size; 173 174 /* Items from the dynamic section. */ 175 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 176 const Elf_Rel *rel; /* Relocation entries */ 177 unsigned long relsize; /* Size in bytes of relocation info */ 178 const Elf_Rela *rela; /* Relocation entries with addend */ 179 unsigned long relasize; /* Size in bytes of addend relocation info */ 180 const Elf_Rel *pltrel; /* PLT relocation entries */ 181 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 182 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 183 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 184 const Elf_Sym *symtab; /* Symbol table */ 185 const char *strtab; /* String table */ 186 unsigned long strsize; /* Size in bytes of string table */ 187 #ifdef __mips__ 188 Elf_Word local_gotno; /* Number of local GOT entries */ 189 Elf_Word symtabno; /* Number of dynamic symbols */ 190 Elf_Word gotsym; /* First dynamic symbol in GOT */ 191 Elf_Addr *mips_pltgot; /* Second PLT GOT */ 192 #endif 193 #ifdef __powerpc64__ 194 Elf_Addr glink; /* GLINK PLT call stub section */ 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 */ 238 239 bool mainprog : 1; /* True if this is the main program */ 240 bool rtld : 1; /* True if this is the dynamic linker */ 241 bool relocated : 1; /* True if processed by relocate_objects() */ 242 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */ 243 bool textrel : 1; /* True if there are relocations to text seg */ 244 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 245 bool bind_now : 1; /* True if all relocations should be made first */ 246 bool traced : 1; /* Already printed in ldd trace output */ 247 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 248 bool init_done : 1; /* Already have added object to init list */ 249 bool tls_done : 1; /* Already allocated offset for static TLS */ 250 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 251 bool z_origin : 1; /* Process rpath and soname tokens */ 252 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 253 bool z_noopen : 1; /* Do not load on dlopen */ 254 bool z_loadfltr : 1; /* Immediately load filtees */ 255 bool z_interpose : 1; /* Interpose all objects but main */ 256 bool z_nodeflib : 1; /* Don't search default library path */ 257 bool z_global : 1; /* Make the object global */ 258 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 259 bool init_scanned: 1; /* Object is already on init list. */ 260 bool on_fini_list: 1; /* Object is already on fini list. */ 261 bool dag_inited : 1; /* Object has its DAG initialized. */ 262 bool filtees_loaded : 1; /* Filtees loaded */ 263 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 264 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 265 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */ 266 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */ 267 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */ 268 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */ 269 bool dlopened : 1; /* dlopen()-ed (vs. load statically) */ 270 bool marker : 1; /* marker on the global obj list */ 271 bool unholdfree : 1; /* unmap upon last unhold */ 272 bool doomed : 1; /* Object cannot be referenced */ 273 274 struct link_map linkmap; /* For GDB and dlinfo() */ 275 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 276 Objlist dagmembers; /* DAG has these members (%) */ 277 dev_t dev; /* Object's filesystem's device */ 278 ino_t ino; /* Object's inode number */ 279 void *priv; /* Platform-dependent */ 280 } Obj_Entry; 281 282 #define RTLD_MAGIC 0xd550b87a 283 #define RTLD_VERSION 1 284 285 TAILQ_HEAD(obj_entry_q, Struct_Obj_Entry); 286 287 #define RTLD_STATIC_TLS_EXTRA 128 288 289 /* Flags to be passed into symlook_ family of functions. */ 290 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 291 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 292 dlsym. */ 293 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */ 294 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in 295 reloc_non_plt(). */ 296 297 /* Flags for load_object(). */ 298 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 299 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 300 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 301 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 302 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 303 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the 304 initialization during the image start. */ 305 306 /* 307 * Symbol cache entry used during relocation to avoid multiple lookups 308 * of the same symbol. 309 */ 310 typedef struct Struct_SymCache { 311 const Elf_Sym *sym; /* Symbol table entry */ 312 const Obj_Entry *obj; /* Shared object which defines it */ 313 } SymCache; 314 315 /* 316 * This structure provides a reentrant way to keep a list of objects and 317 * check which ones have already been processed in some way. 318 */ 319 typedef struct Struct_DoneList { 320 const Obj_Entry **objs; /* Array of object pointers */ 321 unsigned int num_alloc; /* Allocated size of the array */ 322 unsigned int num_used; /* Number of array slots used */ 323 } DoneList; 324 325 struct Struct_RtldLockState { 326 int lockstate; 327 sigjmp_buf env; 328 }; 329 330 struct fill_search_info_args { 331 int request; 332 unsigned int flags; 333 struct dl_serinfo *serinfo; 334 struct dl_serpath *serpath; 335 char *strspace; 336 }; 337 338 /* 339 * The pack of arguments and results for the symbol lookup functions. 340 */ 341 typedef struct Struct_SymLook { 342 const char *name; 343 unsigned long hash; 344 uint32_t hash_gnu; 345 const Ver_Entry *ventry; 346 int flags; 347 const Obj_Entry *defobj_out; 348 const Elf_Sym *sym_out; 349 struct Struct_RtldLockState *lockstate; 350 } SymLook; 351 352 void _rtld_error(const char *, ...) __printflike(1, 2) __exported; 353 void rtld_die(void) __dead2; 354 const char *rtld_strerror(int); 355 Obj_Entry *map_object(int, const char *, const struct stat *); 356 void *xcalloc(size_t, size_t); 357 void *xmalloc(size_t); 358 char *xstrdup(const char *); 359 void *malloc_aligned(size_t size, size_t align); 360 void free_aligned(void *ptr); 361 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 362 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 363 extern bool ld_bind_not; 364 365 void dump_relocations(Obj_Entry *); 366 void dump_obj_relocations(Obj_Entry *); 367 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 368 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 369 370 /* 371 * Function declarations. 372 */ 373 unsigned long elf_hash(const char *); 374 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 375 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 376 void lockdflt_init(void); 377 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); 378 Obj_Entry *globallist_curr(const Obj_Entry *obj); 379 Obj_Entry *globallist_next(const Obj_Entry *obj); 380 void obj_free(Obj_Entry *); 381 Obj_Entry *obj_new(void); 382 void _rtld_bind_start(void); 383 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 384 void symlook_init(SymLook *, const char *); 385 int symlook_obj(SymLook *, const Obj_Entry *); 386 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 387 void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 388 void free_tls(void *, size_t, size_t); 389 void *allocate_module_tls(int index); 390 bool allocate_tls_offset(Obj_Entry *obj); 391 void free_tls_offset(Obj_Entry *obj); 392 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 393 int convert_prot(int elfflags); 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 ifunc_init(Elf_Auxinfo[__min_size(AT_COUNT)]); 406 void pre_init(void); 407 void init_pltgot(Obj_Entry *); 408 void allocate_initial_tls(Obj_Entry *); 409 410 #endif /* } */ 411