rtld.h revision 232831
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: head/libexec/rtld-elf/rtld.h 232831 2012-03-11 20:03:09Z kib $ 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++. */ 64typedef unsigned char bool; 65#define false 0 66#define true 1 67 68extern size_t tls_last_offset; 69extern size_t tls_last_size; 70extern size_t tls_static_space; 71extern int tls_dtv_generation; 72extern int tls_max_index; 73 74extern int main_argc; 75extern char **main_argv; 76extern char **environ; 77 78struct stat; 79struct Struct_Obj_Entry; 80 81/* Lists of shared objects */ 82typedef struct Struct_Objlist_Entry { 83 STAILQ_ENTRY(Struct_Objlist_Entry) link; 84 struct Struct_Obj_Entry *obj; 85} Objlist_Entry; 86 87typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 88 89/* Types of init and fini functions */ 90typedef void (*InitFunc)(void); 91typedef void (*InitArrFunc)(int, char **, char **); 92 93/* Lists of shared object dependencies */ 94typedef struct Struct_Needed_Entry { 95 struct Struct_Needed_Entry *next; 96 struct Struct_Obj_Entry *obj; 97 unsigned long name; /* Offset of name in string table */ 98} Needed_Entry; 99 100typedef struct Struct_Name_Entry { 101 STAILQ_ENTRY(Struct_Name_Entry) link; 102 char name[1]; 103} Name_Entry; 104 105/* Lock object */ 106typedef struct Struct_LockInfo { 107 void *context; /* Client context for creating locks */ 108 void *thelock; /* The one big lock */ 109 /* Debugging aids. */ 110 volatile int rcount; /* Number of readers holding lock */ 111 volatile int wcount; /* Number of writers holding lock */ 112 /* Methods */ 113 void *(*lock_create)(void *context); 114 void (*rlock_acquire)(void *lock); 115 void (*wlock_acquire)(void *lock); 116 void (*rlock_release)(void *lock); 117 void (*wlock_release)(void *lock); 118 void (*lock_destroy)(void *lock); 119 void (*context_destroy)(void *context); 120} LockInfo; 121 122typedef struct Struct_Ver_Entry { 123 Elf_Word hash; 124 unsigned int flags; 125 const char *name; 126 const char *file; 127} Ver_Entry; 128 129#define VER_INFO_HIDDEN 0x01 130 131/* 132 * Shared object descriptor. 133 * 134 * Items marked with "(%)" are dynamically allocated, and must be freed 135 * when the structure is destroyed. 136 * 137 * CAUTION: It appears that the JDK port peeks into these structures. 138 * It looks at "next" and "mapbase" at least. Don't add new members 139 * near the front, until this can be straightened out. 140 */ 141typedef struct Struct_Obj_Entry { 142 /* 143 * These two items have to be set right for compatibility with the 144 * original ElfKit crt1.o. 145 */ 146 Elf_Size magic; /* Magic number (sanity check) */ 147 Elf_Size version; /* Version number of struct format */ 148 149 struct Struct_Obj_Entry *next; 150 char *path; /* Pathname of underlying file (%) */ 151 char *origin_path; /* Directory path of origin file */ 152 int refcount; 153 int dl_refcount; /* Number of times loaded by dlopen */ 154 155 /* These items are computed by map_object() or by digest_phdr(). */ 156 caddr_t mapbase; /* Base address of mapped region */ 157 size_t mapsize; /* Size of mapped region in bytes */ 158 size_t textsize; /* Size of text segment in bytes */ 159 Elf_Addr vaddrbase; /* Base address in shared object file */ 160 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 161 const Elf_Dyn *dynamic; /* Dynamic section */ 162 caddr_t entry; /* Entry point */ 163 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 164 size_t phsize; /* Size of program header in bytes */ 165 const char *interp; /* Pathname of the interpreter, if any */ 166 Elf_Word stack_flags; 167 168 /* TLS information */ 169 int tlsindex; /* Index in DTV for this module */ 170 void *tlsinit; /* Base address of TLS init block */ 171 size_t tlsinitsize; /* Size of TLS init block for this module */ 172 size_t tlssize; /* Size of TLS block for this module */ 173 size_t tlsoffset; /* Offset of static TLS block for this module */ 174 size_t tlsalign; /* Alignment of static TLS block */ 175 176 caddr_t relro_page; 177 size_t relro_size; 178 179 /* Items from the dynamic section. */ 180 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 181 const Elf_Rel *rel; /* Relocation entries */ 182 unsigned long relsize; /* Size in bytes of relocation info */ 183 const Elf_Rela *rela; /* Relocation entries with addend */ 184 unsigned long relasize; /* Size in bytes of addend relocation info */ 185 const Elf_Rel *pltrel; /* PLT relocation entries */ 186 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 187 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 188 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 189 const Elf_Sym *symtab; /* Symbol table */ 190 const char *strtab; /* String table */ 191 unsigned long strsize; /* Size in bytes of string table */ 192#ifdef __mips__ 193 Elf_Word local_gotno; /* Number of local GOT entries */ 194 Elf_Word symtabno; /* Number of dynamic symbols */ 195 Elf_Word gotsym; /* First dynamic symbol in GOT */ 196#endif 197 198 const Elf_Verneed *verneed; /* Required versions. */ 199 Elf_Word verneednum; /* Number of entries in verneed table */ 200 const Elf_Verdef *verdef; /* Provided versions. */ 201 Elf_Word verdefnum; /* Number of entries in verdef table */ 202 const Elf_Versym *versyms; /* Symbol versions table */ 203 204 const Elf_Hashelt *buckets; /* Hash table buckets array */ 205 unsigned long nbuckets; /* Number of buckets */ 206 const Elf_Hashelt *chains; /* Hash table chain array */ 207 unsigned long nchains; /* Number of chains */ 208 209 char *rpath; /* Search path specified in object */ 210 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 211 Needed_Entry *needed_filtees; 212 Needed_Entry *needed_aux_filtees; 213 214 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 215 know about. */ 216 Ver_Entry *vertab; /* Versions required /defined by this object */ 217 int vernum; /* Number of entries in vertab */ 218 219 Elf_Addr init; /* Initialization function to call */ 220 Elf_Addr fini; /* Termination function to call */ 221 Elf_Addr preinit_array; /* Pre-initialization array of functions */ 222 Elf_Addr init_array; /* Initialization array of functions */ 223 Elf_Addr fini_array; /* Termination array of functions */ 224 int preinit_array_num; /* Number of entries in preinit_array */ 225 int init_array_num; /* Number of entries in init_array */ 226 int fini_array_num; /* Number of entries in fini_array */ 227 228 int32_t osrel; /* OSREL note 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 textrel : 1; /* True if there are relocations to text seg */ 233 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 234 bool bind_now : 1; /* True if all relocations should be made first */ 235 bool traced : 1; /* Already printed in ldd trace output */ 236 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 237 bool init_done : 1; /* Already have added object to init list */ 238 bool tls_done : 1; /* Already allocated offset for static TLS */ 239 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 240 bool z_origin : 1; /* Process rpath and soname tokens */ 241 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 242 bool z_noopen : 1; /* Do not load on dlopen */ 243 bool z_loadfltr : 1; /* Immediately load filtees */ 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 gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 251 bool crt_no_init : 1; /* Object' crt does not call _init/_fini */ 252 253 struct link_map linkmap; /* For GDB and dlinfo() */ 254 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 255 Objlist dagmembers; /* DAG has these members (%) */ 256 dev_t dev; /* Object's filesystem's device */ 257 ino_t ino; /* Object's inode number */ 258 void *priv; /* Platform-dependent */ 259} Obj_Entry; 260 261#define RTLD_MAGIC 0xd550b87a 262#define RTLD_VERSION 1 263 264#define RTLD_STATIC_TLS_EXTRA 128 265 266/* Flags to be passed into symlook_ family of functions. */ 267#define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 268#define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 269 dlsym. */ 270 271/* Flags for load_object(). */ 272#define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 273#define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 274#define RTLD_LO_TRACE 0x04 /* Only tracing. */ 275#define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 276#define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 277 278/* 279 * Symbol cache entry used during relocation to avoid multiple lookups 280 * of the same symbol. 281 */ 282typedef struct Struct_SymCache { 283 const Elf_Sym *sym; /* Symbol table entry */ 284 const Obj_Entry *obj; /* Shared object which defines it */ 285} SymCache; 286 287/* 288 * This structure provides a reentrant way to keep a list of objects and 289 * check which ones have already been processed in some way. 290 */ 291typedef struct Struct_DoneList { 292 const Obj_Entry **objs; /* Array of object pointers */ 293 unsigned int num_alloc; /* Allocated size of the array */ 294 unsigned int num_used; /* Number of array slots used */ 295} DoneList; 296 297struct Struct_RtldLockState { 298 int lockstate; 299 sigjmp_buf env; 300}; 301 302/* 303 * The pack of arguments and results for the symbol lookup functions. 304 */ 305typedef struct Struct_SymLook { 306 const char *name; 307 unsigned long hash; 308 const Ver_Entry *ventry; 309 int flags; 310 const Obj_Entry *defobj_out; 311 const Elf_Sym *sym_out; 312 struct Struct_RtldLockState *lockstate; 313} SymLook; 314 315extern void _rtld_error(const char *, ...) __printflike(1, 2); 316extern Obj_Entry *map_object(int, const char *, const struct stat *); 317extern void *xcalloc(size_t); 318extern void *xmalloc(size_t); 319extern char *xstrdup(const char *); 320extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 321extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 322 323extern void dump_relocations (Obj_Entry *); 324extern void dump_obj_relocations (Obj_Entry *); 325extern void dump_Elf_Rel (Obj_Entry *, const Elf_Rel *, u_long); 326extern void dump_Elf_Rela (Obj_Entry *, const Elf_Rela *, u_long); 327 328/* 329 * Function declarations. 330 */ 331unsigned long elf_hash(const char *); 332const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 333 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 334void init_pltgot(Obj_Entry *); 335void lockdflt_init(void); 336void digest_notes(Obj_Entry *, Elf_Addr, Elf_Addr); 337void obj_free(Obj_Entry *); 338Obj_Entry *obj_new(void); 339void _rtld_bind_start(void); 340void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 341void symlook_init(SymLook *, const char *); 342int symlook_obj(SymLook *, const Obj_Entry *); 343void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 344void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 345void free_tls(void *, size_t, size_t); 346void *allocate_module_tls(int index); 347bool allocate_tls_offset(Obj_Entry *obj); 348void free_tls_offset(Obj_Entry *obj); 349const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 350 351/* 352 * MD function declarations. 353 */ 354int do_copy_relocations(Obj_Entry *); 355int reloc_non_plt(Obj_Entry *, Obj_Entry *, struct Struct_RtldLockState *); 356int reloc_plt(Obj_Entry *); 357int reloc_jmpslots(Obj_Entry *, struct Struct_RtldLockState *); 358int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 359int reloc_gnu_ifunc(Obj_Entry *, struct Struct_RtldLockState *); 360void allocate_initial_tls(Obj_Entry *); 361 362#endif /* } */ 363