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 <stdbool.h> 39 #include <setjmp.h> 40 #include <stddef.h> 41 42 #include "rtld_lock.h" 43 #include "rtld_machdep.h" 44 45 #ifndef STANDARD_LIBRARY_PATH 46 #define STANDARD_LIBRARY_PATH "/lib:/usr/lib" 47 #endif 48 49 #define NEW(type) ((type *) xmalloc(sizeof(type))) 50 #define CNEW(type) ((type *) xcalloc(1, sizeof(type))) 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 main_argc; 59 extern char **main_argv; 60 extern char **environ; 61 extern const char *__ld_sharedlib_base; 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 struct Struct_Obj_Entry *next; 141 char *path; /* Pathname of underlying file (%) */ 142 char *origin_path; /* Directory path of origin file */ 143 int refcount; 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 size_t textsize; /* Size of text segment 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; /* Address of first page of read-only data */ 168 size_t relro_size; /* Size of relro page(s) in bytes */ 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 */ 183 184 const Elf_Verneed *verneed; /* Required versions. */ 185 Elf_Word verneednum; /* Number of entries in verneed table */ 186 const Elf_Verdef *verdef; /* Provided versions. */ 187 Elf_Word verdefnum; /* Number of entries in verdef table */ 188 const Elf_Versym *versyms; /* Symbol versions table */ 189 190 const Elf_Hashelt *buckets; /* Hash table buckets array */ 191 unsigned long nbuckets; /* Number of buckets */ 192 const Elf_Hashelt *chains; /* Hash table chain array */ 193 unsigned long nchains; /* Number of entries in chain array */ 194 195 Elf32_Word nbuckets_gnu; /* Number of GNU hash buckets*/ 196 Elf32_Word symndx_gnu; /* 1st accessible symbol on dynsym table */ 197 Elf32_Word maskwords_bm_gnu; /* Bloom filter words - 1 (bitmask) */ 198 Elf32_Word shift2_gnu; /* Bloom filter shift count */ 199 Elf32_Word dynsymcount; /* Total entries in dynsym table */ 200 Elf_Addr *bloom_gnu; /* Bloom filter used by GNU hash func */ 201 const Elf_Hashelt *buckets_gnu; /* GNU hash table bucket array */ 202 const Elf_Hashelt *chain_zero_gnu; /* GNU hash table value array (Zeroed) */ 203 204 char *rpath; /* Search path specified in object */ 205 char *runpath; /* Search path with different priority */ 206 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 207 Needed_Entry *needed_filtees; 208 Needed_Entry *needed_aux_filtees; 209 210 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 211 know about. */ 212 Ver_Entry *vertab; /* Versions required /defined by this object */ 213 int vernum; /* Number of entries in vertab */ 214 215 Elf_Addr init; /* Initialization function to call */ 216 Elf_Addr fini; /* Termination function to call */ 217 Elf_Addr preinit_array; /* Pre-initialization array of functions */ 218 Elf_Addr init_array; /* Initialization array of functions */ 219 Elf_Addr fini_array; /* Termination array of functions */ 220 int preinit_array_num; /* Number of entries in preinit_array */ 221 int init_array_num; /* Number of entries in init_array */ 222 int fini_array_num; /* Number of entries in fini_array */ 223 224 int32_t osrel; /* OSREL note value */ 225 226 bool mainprog : 1; /* True if this is the main program */ 227 bool rtld : 1; /* True if this is the dynamic linker */ 228 bool relocated : 1; /* True if processed by relocate_objects() */ 229 bool ver_checked : 1; /* True if processed by rtld_verify_object_versions */ 230 bool textrel : 1; /* True if there are relocations to text seg */ 231 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 232 bool bind_now : 1; /* True if all relocations should be made first */ 233 bool traced : 1; /* Already printed in ldd trace output */ 234 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 235 bool init_done : 1; /* Already have added object to init list */ 236 bool tls_done : 1; /* Already allocated offset for static TLS */ 237 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 238 bool z_origin : 1; /* Process rpath and soname tokens */ 239 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 240 bool z_noopen : 1; /* Do not load on dlopen */ 241 bool z_loadfltr : 1; /* Immediately load filtees */ 242 bool z_interpose : 1; /* Interpose all objects but main */ 243 bool z_nodeflib : 1; /* Don't search default library path */ 244 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 245 bool init_scanned: 1; /* Object is already on init list. */ 246 bool on_fini_list: 1; /* Object is already on fini list. */ 247 bool dag_inited : 1; /* Object has its DAG initialized. */ 248 bool filtees_loaded : 1; /* Filtees loaded */ 249 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 250 bool irelative_nonplt : 1; /* Object has R_MACHDEP_IRELATIVE non-plt relocs */ 251 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 252 bool non_plt_gnu_ifunc : 1; /* Object has non-plt IFUNC references */ 253 bool crt_no_init : 1; /* Object's crt does not call _init/_fini */ 254 bool note_present : 1; /* True if at least one PT_NOTE header found */ 255 bool valid_hash_sysv : 1; /* A valid System V hash hash tag is available */ 256 bool valid_hash_gnu : 1; /* A valid GNU hash tag is available */ 257 bool relro_protected : 1; /* relro section has been protected */ 258 bool static_tls : 1; /* Object wants to use static TLS space */ 259 bool static_tls_copied : 1; /* Object's static TLS space initialized */ 260 261 struct link_map linkmap; /* For GDB and dlinfo() */ 262 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 263 Objlist dagmembers; /* DAG has these members (%) */ 264 dev_t dev; /* Object's filesystem's device */ 265 ino_t ino; /* Object's inode number */ 266 void *priv; /* Platform-dependent */ 267 } Obj_Entry; 268 269 #define RTLD_MAGIC 0xd550b87a 270 #define RTLD_VERSION 1 271 272 #define RTLD_FUNCTRACE "_rtld_functrace" 273 274 /* Flags to be passed into symlook_ family of functions. */ 275 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 276 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 277 dlsym. */ 278 #define SYMLOOK_EARLY 0x04 /* Symlook is done during initialization. */ 279 #define SYMLOOK_IFUNC 0x08 /* Allow IFUNC processing in 280 reloc_non_plt(). */ 281 282 /* Flags for load_object(). */ 283 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 284 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 285 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 286 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 287 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 288 #define RTLD_LO_EARLY 0x20 /* Do not call ctors, postpone it to the 289 initialization during the image start. */ 290 291 /* 292 * Symbol cache entry used during relocation to avoid multiple lookups 293 * of the same symbol. 294 */ 295 typedef struct Struct_SymCache { 296 const Elf_Sym *sym; /* Symbol table entry */ 297 const Obj_Entry *obj; /* Shared object which defines it */ 298 } SymCache; 299 300 /* 301 * This structure provides a reentrant way to keep a list of objects and 302 * check which ones have already been processed in some way. 303 */ 304 typedef struct Struct_DoneList { 305 const Obj_Entry **objs; /* Array of object pointers */ 306 unsigned int num_alloc; /* Allocated size of the array */ 307 unsigned int num_used; /* Number of array slots used */ 308 } DoneList; 309 310 struct Struct_RtldLockState { 311 int lockstate; 312 sigjmp_buf env; 313 }; 314 315 struct fill_search_info_args { 316 int request; 317 unsigned int flags; 318 struct dl_serinfo *serinfo; 319 struct dl_serpath *serpath; 320 char *strspace; 321 }; 322 323 /* 324 * The pack of arguments and results for the symbol lookup functions. 325 */ 326 typedef struct Struct_SymLook { 327 const char *name; 328 unsigned long hash; 329 uint_fast32_t hash_gnu; 330 const Ver_Entry *ventry; 331 int flags; 332 const Obj_Entry *defobj_out; 333 const Elf_Sym *sym_out; 334 struct Struct_RtldLockState *lockstate; 335 } SymLook; 336 337 void _rtld_error(const char *, ...) __printflike(1, 2); 338 const char *rtld_strerror(int); 339 Obj_Entry *map_object(int, const char *, const struct stat *); 340 void *xcalloc(size_t, size_t); 341 void *xmalloc(size_t); 342 char *xstrdup(const char *); 343 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 344 345 void dump_relocations(Obj_Entry *); 346 void dump_obj_relocations(Obj_Entry *); 347 void dump_Elf_Rel(Obj_Entry *, const Elf_Rel *, u_long); 348 void dump_Elf_Rela(Obj_Entry *, const Elf_Rela *, u_long); 349 350 /* 351 * Function declarations. 352 */ 353 const char *basename(const char *); 354 unsigned long elf_hash(const char *); 355 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 356 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 357 void init_pltgot(Obj_Entry *); 358 void lockdflt_init(void); 359 void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); 360 void obj_free(Obj_Entry *); 361 Obj_Entry *obj_new(void); 362 void _rtld_bind_start(void); 363 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 364 void symlook_init(SymLook *, const char *); 365 int symlook_obj(SymLook *, const Obj_Entry *); 366 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 367 struct tls_tcb *allocate_tls(Obj_Entry *); 368 void free_tls(struct tls_tcb *); 369 void *allocate_module_tls(int index); 370 bool allocate_tls_offset(Obj_Entry *obj); 371 void free_tls_offset(Obj_Entry *obj); 372 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 373 int convert_prot(int); /* Elf flags -> mmap protection */ 374 375 /* 376 * MD function declarations. 377 */ 378 int do_copy_relocations(Obj_Entry *); 379 int reloc_non_plt(Obj_Entry *, Obj_Entry *, int flags, 380 struct Struct_RtldLockState *); 381 int reloc_plt(Obj_Entry *); 382 int reloc_jmpslots(Obj_Entry *, int flags, struct Struct_RtldLockState *); 383 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 384 int reloc_iresolve_nonplt(Obj_Entry *, struct Struct_RtldLockState *); 385 int reloc_gnu_ifunc(Obj_Entry *, int flags, struct Struct_RtldLockState *); 386 void allocate_initial_tls(Obj_Entry *); 387 388 #endif /* } */ 389