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 #ifdef COMPAT_32BIT 45 #undef STANDARD_LIBRARY_PATH 46 #undef _PATH_ELF_HINTS 47 #define _PATH_ELF_HINTS "/var/run/ld-elf32.so.hints" 48 /* For running 32 bit binaries */ 49 #define STANDARD_LIBRARY_PATH "/lib32:/usr/lib32" 50 #define LD_ "LD_32_" 51 #endif 52 53 #ifndef STANDARD_LIBRARY_PATH 54 #define STANDARD_LIBRARY_PATH "/lib:/usr/lib" 55 #endif 56 #ifndef LD_ 57 #define LD_ "LD_" 58 #endif 59 60 #define NEW(type) ((type *) xmalloc(sizeof(type))) 61 #define CNEW(type) ((type *) xcalloc(sizeof(type))) 62 63 /* We might as well do booleans like C++. */ 64 typedef unsigned char bool; 65 #define false 0 66 #define true 1 67 68 extern size_t tls_last_offset; 69 extern size_t tls_last_size; 70 extern size_t tls_static_space; 71 extern int tls_dtv_generation; 72 extern int tls_max_index; 73 74 struct stat; 75 struct Struct_Obj_Entry; 76 77 /* Lists of shared objects */ 78 typedef struct Struct_Objlist_Entry { 79 STAILQ_ENTRY(Struct_Objlist_Entry) link; 80 struct Struct_Obj_Entry *obj; 81 } Objlist_Entry; 82 83 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 84 85 /* Types of init and fini functions */ 86 typedef void (*InitFunc)(void); 87 88 /* Lists of shared object dependencies */ 89 typedef struct Struct_Needed_Entry { 90 struct Struct_Needed_Entry *next; 91 struct Struct_Obj_Entry *obj; 92 unsigned long name; /* Offset of name in string table */ 93 } Needed_Entry; 94 95 typedef struct Struct_Name_Entry { 96 STAILQ_ENTRY(Struct_Name_Entry) link; 97 char name[1]; 98 } Name_Entry; 99 100 /* Lock object */ 101 typedef struct Struct_LockInfo { 102 void *context; /* Client context for creating locks */ 103 void *thelock; /* The one big lock */ 104 /* Debugging aids. */ 105 volatile int rcount; /* Number of readers holding lock */ 106 volatile int wcount; /* Number of writers holding lock */ 107 /* Methods */ 108 void *(*lock_create)(void *context); 109 void (*rlock_acquire)(void *lock); 110 void (*wlock_acquire)(void *lock); 111 void (*rlock_release)(void *lock); 112 void (*wlock_release)(void *lock); 113 void (*lock_destroy)(void *lock); 114 void (*context_destroy)(void *context); 115 } LockInfo; 116 117 typedef struct Struct_Ver_Entry { 118 Elf_Word hash; 119 unsigned int flags; 120 const char *name; 121 const char *file; 122 } Ver_Entry; 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 struct Struct_Obj_Entry *next; 145 char *path; /* Pathname of underlying file (%) */ 146 char *origin_path; /* Directory path of origin file */ 147 int refcount; 148 int dl_refcount; /* Number of times loaded by dlopen */ 149 150 /* These items are computed by map_object() or by digest_phdr(). */ 151 caddr_t mapbase; /* Base address of mapped region */ 152 size_t mapsize; /* Size of mapped region in bytes */ 153 size_t textsize; /* Size of text segment 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 /* 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_Rel *pltrel; /* PLT relocation entries */ 178 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 179 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 180 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 181 const Elf_Sym *symtab; /* Symbol table */ 182 const char *strtab; /* String table */ 183 unsigned long strsize; /* Size in bytes of string table */ 184 #ifdef __mips__ 185 Elf_Word local_gotno; /* Number of local GOT entries */ 186 Elf_Word symtabno; /* Number of dynamic symbols */ 187 Elf_Word gotsym; /* First dynamic symbol in GOT */ 188 #endif 189 190 const Elf_Verneed *verneed; /* Required versions. */ 191 Elf_Word verneednum; /* Number of entries in verneed table */ 192 const Elf_Verdef *verdef; /* Provided versions. */ 193 Elf_Word verdefnum; /* Number of entries in verdef table */ 194 const Elf_Versym *versyms; /* Symbol versions table */ 195 196 const Elf_Hashelt *buckets; /* Hash table buckets array */ 197 unsigned long nbuckets; /* Number of buckets */ 198 const Elf_Hashelt *chains; /* Hash table chain array */ 199 unsigned long nchains; /* Number of chains */ 200 201 char *rpath; /* Search path specified in object */ 202 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 203 Needed_Entry *needed_filtees; 204 Needed_Entry *needed_aux_filtees; 205 206 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 207 know about. */ 208 Ver_Entry *vertab; /* Versions required /defined by this object */ 209 int vernum; /* Number of entries in vertab */ 210 211 Elf_Addr init; /* Initialization function to call */ 212 Elf_Addr fini; /* Termination function to call */ 213 214 bool mainprog : 1; /* True if this is the main program */ 215 bool rtld : 1; /* True if this is the dynamic linker */ 216 bool textrel : 1; /* True if there are relocations to text seg */ 217 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 218 bool bind_now : 1; /* True if all relocations should be made first */ 219 bool traced : 1; /* Already printed in ldd trace output */ 220 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 221 bool init_done : 1; /* Already have added object to init list */ 222 bool tls_done : 1; /* Already allocated offset for static TLS */ 223 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 224 bool z_origin : 1; /* Process rpath and soname tokens */ 225 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 226 bool z_noopen : 1; /* Do not load on dlopen */ 227 bool z_loadfltr : 1; /* Immediately load filtees */ 228 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 229 bool init_scanned: 1; /* Object is already on init list. */ 230 bool on_fini_list: 1; /* Object is already on fini list. */ 231 bool dag_inited : 1; /* Object has its DAG initialized. */ 232 bool filtees_loaded : 1; /* Filtees loaded */ 233 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 234 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 235 236 struct link_map linkmap; /* For GDB and dlinfo() */ 237 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 238 Objlist dagmembers; /* DAG has these members (%) */ 239 dev_t dev; /* Object's filesystem's device */ 240 ino_t ino; /* Object's inode number */ 241 void *priv; /* Platform-dependent */ 242 } Obj_Entry; 243 244 #define RTLD_MAGIC 0xd550b87a 245 #define RTLD_VERSION 1 246 247 #define RTLD_STATIC_TLS_EXTRA 128 248 249 /* Flags to be passed into symlook_ family of functions. */ 250 #define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 251 #define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 252 dlsym. */ 253 254 /* Flags for load_object(). */ 255 #define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 256 #define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 257 #define RTLD_LO_TRACE 0x04 /* Only tracing. */ 258 #define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 259 #define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 260 261 /* 262 * Symbol cache entry used during relocation to avoid multiple lookups 263 * of the same symbol. 264 */ 265 typedef struct Struct_SymCache { 266 const Elf_Sym *sym; /* Symbol table entry */ 267 const Obj_Entry *obj; /* Shared object which defines it */ 268 } SymCache; 269 270 /* 271 * This structure provides a reentrant way to keep a list of objects and 272 * check which ones have already been processed in some way. 273 */ 274 typedef struct Struct_DoneList { 275 const Obj_Entry **objs; /* Array of object pointers */ 276 unsigned int num_alloc; /* Allocated size of the array */ 277 unsigned int num_used; /* Number of array slots used */ 278 } DoneList; 279 280 struct Struct_RtldLockState { 281 int lockstate; 282 sigjmp_buf env; 283 }; 284 285 /* 286 * The pack of arguments and results for the symbol lookup functions. 287 */ 288 typedef struct Struct_SymLook { 289 const char *name; 290 unsigned long hash; 291 const Ver_Entry *ventry; 292 int flags; 293 const Obj_Entry *defobj_out; 294 const Elf_Sym *sym_out; 295 struct Struct_RtldLockState *lockstate; 296 } SymLook; 297 298 extern void _rtld_error(const char *, ...) __printflike(1, 2); 299 extern Obj_Entry *map_object(int, const char *, const struct stat *); 300 extern void *xcalloc(size_t); 301 extern void *xmalloc(size_t); 302 extern char *xstrdup(const char *); 303 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 304 extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 305 306 extern void dump_relocations (Obj_Entry *); 307 extern void dump_obj_relocations (Obj_Entry *); 308 extern void dump_Elf_Rel (Obj_Entry *, const Elf_Rel *, u_long); 309 extern void dump_Elf_Rela (Obj_Entry *, const Elf_Rela *, u_long); 310 311 /* 312 * Function declarations. 313 */ 314 unsigned long elf_hash(const char *); 315 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 316 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 317 void init_pltgot(Obj_Entry *); 318 void lockdflt_init(void); 319 void obj_free(Obj_Entry *); 320 Obj_Entry *obj_new(void); 321 void _rtld_bind_start(void); 322 void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 323 void symlook_init(SymLook *, const char *); 324 int symlook_obj(SymLook *, const Obj_Entry *); 325 void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 326 void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 327 void free_tls(void *, size_t, size_t); 328 void *allocate_module_tls(int index); 329 bool allocate_tls_offset(Obj_Entry *obj); 330 void free_tls_offset(Obj_Entry *obj); 331 const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 332 333 /* 334 * MD function declarations. 335 */ 336 int do_copy_relocations(Obj_Entry *); 337 int reloc_non_plt(Obj_Entry *, Obj_Entry *, struct Struct_RtldLockState *); 338 int reloc_plt(Obj_Entry *); 339 int reloc_jmpslots(Obj_Entry *, struct Struct_RtldLockState *); 340 int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 341 int reloc_gnu_ifunc(Obj_Entry *, struct Struct_RtldLockState *); 342 void allocate_initial_tls(Obj_Entry *); 343 344 #endif /* } */ 345