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 #define NEW(type) ((type *) xmalloc(sizeof(type))) 45 #define CNEW(type) ((type *) xcalloc(1, sizeof(type))) 46 47 /* We might as well do booleans like C++. */ 48 typedef unsigned char bool; 49 #define false 0 50 #define true 1 51 52 extern size_t tls_last_offset; 53 extern size_t tls_last_size; 54 extern size_t tls_static_space; 55 extern int tls_dtv_generation; 56 extern int tls_max_index; 57 58 extern int npagesizes; 59 extern size_t *pagesizes; 60 61 extern int main_argc; 62 extern char **main_argv; 63 extern char **environ; 64 65 struct stat; 66 struct Struct_Obj_Entry; 67 68 /* Lists of shared objects */ 69 typedef struct Struct_Objlist_Entry { 70 STAILQ_ENTRY(Struct_Objlist_Entry) link; 71 struct Struct_Obj_Entry *obj; 72 } Objlist_Entry; 73 74 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 75 76 /* Types of init and fini functions */ 77 typedef void (*InitFunc)(void); 78 typedef void (*InitArrFunc)(int, char **, char **); 79 80 /* Lists of shared object dependencies */ 81 typedef struct Struct_Needed_Entry { 82 struct Struct_Needed_Entry *next; 83 struct Struct_Obj_Entry *obj; 84 unsigned long name; /* Offset of name in string table */ 85 } Needed_Entry; 86 87 typedef struct Struct_Name_Entry { 88 STAILQ_ENTRY(Struct_Name_Entry) link; 89 char name[1]; 90 } Name_Entry; 91 92 /* Lock object */ 93 typedef struct Struct_LockInfo { 94 void *context; /* Client context for creating locks */ 95 void *thelock; /* The one big lock */ 96 /* Debugging aids. */ 97 volatile int rcount; /* Number of readers holding lock */ 98 volatile int wcount; /* Number of writers holding lock */ 99 /* Methods */ 100 void *(*lock_create)(void *context); 101 void (*rlock_acquire)(void *lock); 102 void (*wlock_acquire)(void *lock); 103 void (*rlock_release)(void *lock); 104 void (*wlock_release)(void *lock); 105 void (*lock_destroy)(void *lock); 106 void (*context_destroy)(void *context); 107 } LockInfo; 108 109 typedef struct Struct_Ver_Entry { 110 Elf_Word hash; 111 unsigned int flags; 112 const char *name; 113 const char *file; 114 } Ver_Entry; 115 116 typedef struct Struct_Sym_Match_Result { 117 const Elf_Sym *sym_out; 118 const Elf_Sym *vsymp; 119 int vcount; 120 } Sym_Match_Result; 121 122 #define VER_INFO_HIDDEN 0x01 123 124 /* 125 * Shared object descriptor. 126 * 127 * Items marked with "(%)" are dynamically allocated, and must be freed 128 * when the structure is destroyed. 129 * 130 * CAUTION: It appears that the JDK port peeks into these structures. 131 * It looks at "next" and "mapbase" at least. Don't add new members 132 * near the front, until this can be straightened out. 133 */ 134 typedef struct Struct_Obj_Entry { 135 /* 136 * These two items have to be set right for compatibility with the 137 * original ElfKit crt1.o. 138 */ 139 Elf_Size magic; /* Magic number (sanity check) */ 140 Elf_Size version; /* Version number of struct format */ 141 142 struct Struct_Obj_Entry *next; 143 char *path; /* Pathname of underlying file (%) */ 144 char *origin_path; /* Directory path of origin file */ 145 int refcount; 146 int dl_refcount; /* Number of times loaded by dlopen */ 147 148 /* These items are computed by map_object() or by digest_phdr(). */ 149 caddr_t mapbase; /* Base address of mapped region */ 150 size_t mapsize; /* Size of mapped region in bytes */ 151 size_t textsize; /* Size of text segment in bytes */ 152 Elf_Addr vaddrbase; /* Base address in shared object file */ 153 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 154 const Elf_Dyn *dynamic; /* Dynamic section */ 155 caddr_t entry; /* Entry point */ 156 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 157 size_t phsize; /* Size of program header in bytes */ 158 const char *interp; /* Pathname of the interpreter, if any */ 159 Elf_Word stack_flags; 160 161 /* TLS information */ 162 int tlsindex; /* Index in DTV for this module */ 163 void *tlsinit; /* Base address of TLS init block */ 164 size_t tlsinitsize; /* Size of TLS init block for this module */ 165 size_t tlssize; /* Size of TLS block for this module */ 166 size_t tlsoffset; /* Offset of static TLS block for this module */ 167 size_t tlsalign; /* Alignment of static TLS block */ 168 169 caddr_t relro_page; 170 size_t relro_size; 171 172 /* Items from the dynamic section. */ 173 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 174 const Elf_Rel *rel; /* Relocation entries */ 175 unsigned long relsize; /* Size in bytes of relocation info */ 176 const Elf_Rela *rela; /* Relocation entries with addend */ 177 unsigned long relasize; /* Size in bytes of addend relocation info */ 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 __mips__ 186 Elf_Word local_gotno; /* Number of local GOT entries */ 187 Elf_Word symtabno; /* Number of dynamic symbols */ 188 Elf_Word gotsym; /* First dynamic symbol in GOT */ 189 #endif 190 #ifdef __powerpc64__ 191 Elf_Addr glink; /* GLINK PLT call stub section */ 192 #endif 193 194 const Elf_Verneed *verneed; /* Required versions. */ 195 Elf_Word verneednum; /* Number of entries in verneed table */ 196 const Elf_Verdef *verdef; /* Provided versions. */ 197 Elf_Word verdefnum; /* Number of entries in verdef table */ 198 const Elf_Versym *versyms; /* Symbol versions table */ 199 200 const Elf_Hashelt *buckets; /* Hash table buckets array */ 201 unsigned long nbuckets; /* Number of buckets */ 202 const Elf_Hashelt *chains; /* Hash table chain array */ 203 unsigned long nchains; /* Number of entries in chain array */ 204 205 Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/ 206 Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */ 207 Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */ 208 Elf32_Word shift2_gnu; /* Bloom filter shift count */ 209 Elf32_Word dynsymcount; /* Total entries in dynsym table */ 210 Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */ 211 const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */ 212 const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */ 213 214 char *rpath; /* Search path specified in object */ 215 char *runpath; /* Search path with different priority */ 216 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 217 Needed_Entry *needed_filtees; 218 Needed_Entry *needed_aux_filtees; 219 220 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 221 know about. */ 222 Ver_Entry *vertab; /* Versions required /defined by this object */ 223 int vernum; /* Number of entries in vertab */ 224 225 Elf_Addr init; /* Initialization function to call */ 226 Elf_Addr fini; /* Termination function to call */ 227 Elf_Addr preinit_array; /* Pre-initialization array of functions */ 228 Elf_Addr init_array; /* Initialization array of functions */ 229 Elf_Addr fini_array; /* Termination array of functions */ 230 int preinit_array_num; /* Number of entries in preinit_array */ 231 int init_array_num; /* Number of entries in init_array */ 232 int fini_array_num; /* Number of entries in fini_array */ 233 234 int32_t osrel; /* OSREL note 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_done : 1; /* Already allocated offset for static TLS */ 247 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 248 bool z_origin : 1; /* Process rpath and soname tokens */ 249 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 250 bool z_noopen : 1; /* Do not load on dlopen */ 251 bool z_loadfltr : 1; /* Immediately load filtees */ 252 bool z_interpose : 1; /* Interpose all objects but main */ 253 bool z_nodeflib : 1; /* Don't search default library path */ 254 bool z_global : 1; /* Make the object global */ 255 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 256 bool init_scanned: 1; /* Object is already on init list. */ 257 bool on_fini_list: 1; /* Object is already on fini list. */ 258 bool dag_inited : 1; /* Object has its DAG initialized. */ 259 bool filtees_loaded : 1; /* Filtees loaded */ 260 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 261 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 262 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */ 263 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */ 264 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */ 265 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */ 266 bool dlopened : 1; /* dlopen()-ed (vs. load statically) */ 267 268 struct link_map linkmap; /* For GDB and dlinfo() */ 269 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 270 Objlist dagmembers; /* DAG has these members (%) */ 271 dev_t dev; /* Object's filesystem's device */ 272 ino_t ino; /* Object's inode number */ 273 void *priv; /* Platform-dependent */ 274 } Obj_Entry; 275 276 #define RTLD_MAGIC 0xd550b87a 277 #define RTLD_VERSION 1 278 279 #define RTLD_STATIC_TLS_EXTRA 128 280 281 /* Flags to be passed into symlook_ family of functions. */ 282 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 283 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 284 dlsym. */ 285 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */ 286 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in 287 reloc_non_plt(). */ 288 289 /* Flags for load_object(). */ 290 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 291 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 292 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 293 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 294 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 295 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the 296 initialization during the image start. */ 297 298 /* 299 * Symbol cache entry used during relocation to avoid multiple lookups 300 * of the same symbol. 301 */ 302 typedef struct Struct_SymCache { 303 const Elf_Sym *sym; /* Symbol table entry */ 304 const Obj_Entry *obj; /* Shared object which defines it */ 305 } SymCache; 306 307 /* 308 * This structure provides a reentrant way to keep a list of objects and 309 * check which ones have already been processed in some way. 310 */ 311 typedef struct Struct_DoneList { 312 const Obj_Entry **objs; /* Array of object pointers */ 313 unsigned int num_alloc; /* Allocated size of the array */ 314 unsigned int num_used; /* Number of array slots used */ 315 } DoneList; 316 317 struct Struct_RtldLockState { 318 int lockstate; 319 sigjmp_buf env; 320 }; 321 322 struct fill_search_info_args { 323 int request; 324 unsigned int flags; 325 struct dl_serinfo *serinfo; 326 struct dl_serpath *serpath; 327 char *strspace; 328 }; 329 330 /* 331 * The pack of arguments and results for the symbol lookup functions. 332 */ 333 typedef struct Struct_SymLook { 334 const char *name; 335 unsigned long hash; 336 uint32_t hash_gnu; 337 const Ver_Entry *ventry; 338 int flags; 339 const Obj_Entry *defobj_out; 340 const Elf_Sym *sym_out; 341 struct Struct_RtldLockState *lockstate; 342 } SymLook; 343 344 void _rtld_error(const char *, ...) __printflike(1, 2) __exported; 345 void rtld_die(void) __dead2; 346 const char *rtld_strerror(int); 347 Obj_Entry *map_object(int, const char *, const struct stat *); 348 void *xcalloc(size_t, size_t); 349 void *xmalloc(size_t); 350 char *xstrdup(const char *); 351 void *malloc_aligned(size_t size, size_t align); 352 void free_aligned(void *ptr); 353 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 354 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 355 356 void dump_relocations(Obj_Entry *); 357 void dump_obj_relocations(Obj_Entry *); 358 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 359 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 360 361 /* 362 * Function declarations. 363 */ 364 unsigned long elf_hash(const char *); 365 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 366 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 367 void init_pltgot(Obj_Entry *); 368 void lockdflt_init(void); 369 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); 370 void obj_free(Obj_Entry *); 371 Obj_Entry *obj_new(void); 372 void _rtld_bind_start(void); 373 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 374 void symlook_init(SymLook *, const char *); 375 int symlook_obj(SymLook *, const Obj_Entry *); 376 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 377 void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 378 void free_tls(void *, size_t, size_t); 379 void *allocate_module_tls(int index); 380 bool allocate_tls_offset(Obj_Entry *obj); 381 void free_tls_offset(Obj_Entry *obj); 382 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 383 384 /* 385 * MD function declarations. 386 */ 387 int do_copy_relocations(Obj_Entry *); 388 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags, 389 struct Struct_RtldLockState *); 390 int reloc_plt(Obj_Entry *); 391 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *); 392 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 393 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *); 394 void allocate_initial_tls(Obj_Entry *); 395 396 #endif /* } */ 397