rtld.h revision 230784
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 230784 2012-01-30 19:52:17Z 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 74struct stat; 75struct Struct_Obj_Entry; 76 77/* Lists of shared objects */ 78typedef struct Struct_Objlist_Entry { 79 STAILQ_ENTRY(Struct_Objlist_Entry) link; 80 struct Struct_Obj_Entry *obj; 81} Objlist_Entry; 82 83typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 84 85/* Types of init and fini functions */ 86typedef void (*InitFunc)(void); 87 88/* Lists of shared object dependencies */ 89typedef 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 95typedef struct Struct_Name_Entry { 96 STAILQ_ENTRY(Struct_Name_Entry) link; 97 char name[1]; 98} Name_Entry; 99 100/* Lock object */ 101typedef 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 117typedef 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 */ 136typedef 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 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#endif 192 193 const Elf_Verneed *verneed; /* Required versions. */ 194 Elf_Word verneednum; /* Number of entries in verneed table */ 195 const Elf_Verdef *verdef; /* Provided versions. */ 196 Elf_Word verdefnum; /* Number of entries in verdef table */ 197 const Elf_Versym *versyms; /* Symbol versions table */ 198 199 const Elf_Hashelt *buckets; /* Hash table buckets array */ 200 unsigned long nbuckets; /* Number of buckets */ 201 const Elf_Hashelt *chains; /* Hash table chain array */ 202 unsigned long nchains; /* Number of chains */ 203 204 char *rpath; /* Search path specified in object */ 205 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 206 Needed_Entry *needed_filtees; 207 Needed_Entry *needed_aux_filtees; 208 209 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 210 know about. */ 211 Ver_Entry *vertab; /* Versions required /defined by this object */ 212 int vernum; /* Number of entries in vertab */ 213 214 Elf_Addr init; /* Initialization function to call */ 215 Elf_Addr fini; /* Termination function to call */ 216 217 bool mainprog : 1; /* True if this is the main program */ 218 bool rtld : 1; /* True if this is the dynamic linker */ 219 bool textrel : 1; /* True if there are relocations to text seg */ 220 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 221 bool bind_now : 1; /* True if all relocations should be made first */ 222 bool traced : 1; /* Already printed in ldd trace output */ 223 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 224 bool init_done : 1; /* Already have added object to init list */ 225 bool tls_done : 1; /* Already allocated offset for static TLS */ 226 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 227 bool z_origin : 1; /* Process rpath and soname tokens */ 228 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 229 bool z_noopen : 1; /* Do not load on dlopen */ 230 bool z_loadfltr : 1; /* Immediately load filtees */ 231 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 232 bool init_scanned: 1; /* Object is already on init list. */ 233 bool on_fini_list: 1; /* Object is already on fini list. */ 234 bool dag_inited : 1; /* Object has its DAG initialized. */ 235 bool filtees_loaded : 1; /* Filtees loaded */ 236 bool irelative : 1; /* Object has R_MACHDEP_IRELATIVE relocs */ 237 bool gnu_ifunc : 1; /* Object has references to STT_GNU_IFUNC */ 238 239 struct link_map linkmap; /* For GDB and dlinfo() */ 240 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 241 Objlist dagmembers; /* DAG has these members (%) */ 242 dev_t dev; /* Object's filesystem's device */ 243 ino_t ino; /* Object's inode number */ 244 void *priv; /* Platform-dependent */ 245} Obj_Entry; 246 247#define RTLD_MAGIC 0xd550b87a 248#define RTLD_VERSION 1 249 250#define RTLD_STATIC_TLS_EXTRA 128 251 252/* Flags to be passed into symlook_ family of functions. */ 253#define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 254#define SYMLOOK_DLSYM 0x02 /* Return newest versioned symbol. Used by 255 dlsym. */ 256 257/* Flags for load_object(). */ 258#define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 259#define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 260#define RTLD_LO_TRACE 0x04 /* Only tracing. */ 261#define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 262#define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 263 264/* 265 * Symbol cache entry used during relocation to avoid multiple lookups 266 * of the same symbol. 267 */ 268typedef struct Struct_SymCache { 269 const Elf_Sym *sym; /* Symbol table entry */ 270 const Obj_Entry *obj; /* Shared object which defines it */ 271} SymCache; 272 273/* 274 * This structure provides a reentrant way to keep a list of objects and 275 * check which ones have already been processed in some way. 276 */ 277typedef struct Struct_DoneList { 278 const Obj_Entry **objs; /* Array of object pointers */ 279 unsigned int num_alloc; /* Allocated size of the array */ 280 unsigned int num_used; /* Number of array slots used */ 281} DoneList; 282 283struct Struct_RtldLockState { 284 int lockstate; 285 sigjmp_buf env; 286}; 287 288/* 289 * The pack of arguments and results for the symbol lookup functions. 290 */ 291typedef struct Struct_SymLook { 292 const char *name; 293 unsigned long hash; 294 const Ver_Entry *ventry; 295 int flags; 296 const Obj_Entry *defobj_out; 297 const Elf_Sym *sym_out; 298 struct Struct_RtldLockState *lockstate; 299} SymLook; 300 301extern void _rtld_error(const char *, ...) __printflike(1, 2); 302extern Obj_Entry *map_object(int, const char *, const struct stat *); 303extern void *xcalloc(size_t); 304extern void *xmalloc(size_t); 305extern char *xstrdup(const char *); 306extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 307extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 308 309extern void dump_relocations (Obj_Entry *); 310extern void dump_obj_relocations (Obj_Entry *); 311extern void dump_Elf_Rel (Obj_Entry *, const Elf_Rel *, u_long); 312extern void dump_Elf_Rela (Obj_Entry *, const Elf_Rela *, u_long); 313 314/* 315 * Function declarations. 316 */ 317unsigned long elf_hash(const char *); 318const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 319 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 320void init_pltgot(Obj_Entry *); 321void lockdflt_init(void); 322void obj_free(Obj_Entry *); 323Obj_Entry *obj_new(void); 324void _rtld_bind_start(void); 325void *rtld_resolve_ifunc(const Obj_Entry *obj, const Elf_Sym *def); 326void symlook_init(SymLook *, const char *); 327int symlook_obj(SymLook *, const Obj_Entry *); 328void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 329void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 330void free_tls(void *, size_t, size_t); 331void *allocate_module_tls(int index); 332bool allocate_tls_offset(Obj_Entry *obj); 333void free_tls_offset(Obj_Entry *obj); 334const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 335 336/* 337 * MD function declarations. 338 */ 339int do_copy_relocations(Obj_Entry *); 340int reloc_non_plt(Obj_Entry *, Obj_Entry *, struct Struct_RtldLockState *); 341int reloc_plt(Obj_Entry *); 342int reloc_jmpslots(Obj_Entry *, struct Struct_RtldLockState *); 343int reloc_iresolve(Obj_Entry *, struct Struct_RtldLockState *); 344int reloc_gnu_ifunc(Obj_Entry *, struct Struct_RtldLockState *); 345void allocate_initial_tls(Obj_Entry *); 346 347#endif /* } */ 348