rtld.h revision 218476
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 218476 2011-02-09 09:20:27Z 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 <setjmp.h> 38#include <stddef.h> 39 40#include "rtld_lock.h" 41#include "rtld_machdep.h" 42 43#ifdef COMPAT_32BIT 44#undef STANDARD_LIBRARY_PATH 45#undef _PATH_ELF_HINTS 46#define _PATH_ELF_HINTS "/var/run/ld-elf32.so.hints" 47/* For running 32 bit binaries */ 48#define STANDARD_LIBRARY_PATH "/lib32:/usr/lib32" 49#define LD_ "LD_32_" 50#endif 51 52#ifndef STANDARD_LIBRARY_PATH 53#define STANDARD_LIBRARY_PATH "/lib:/usr/lib" 54#endif 55#ifndef LD_ 56#define LD_ "LD_" 57#endif 58 59#define NEW(type) ((type *) xmalloc(sizeof(type))) 60#define CNEW(type) ((type *) xcalloc(sizeof(type))) 61 62/* We might as well do booleans like C++. */ 63typedef unsigned char bool; 64#define false 0 65#define true 1 66 67extern size_t tls_last_offset; 68extern size_t tls_last_size; 69extern size_t tls_static_space; 70extern int tls_dtv_generation; 71extern int tls_max_index; 72 73struct stat; 74struct Struct_Obj_Entry; 75 76/* Lists of shared objects */ 77typedef struct Struct_Objlist_Entry { 78 STAILQ_ENTRY(Struct_Objlist_Entry) link; 79 struct Struct_Obj_Entry *obj; 80} Objlist_Entry; 81 82typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 83 84/* Types of init and fini functions */ 85typedef void (*InitFunc)(void); 86 87/* Lists of shared object dependencies */ 88typedef struct Struct_Needed_Entry { 89 struct Struct_Needed_Entry *next; 90 struct Struct_Obj_Entry *obj; 91 unsigned long name; /* Offset of name in string table */ 92} Needed_Entry; 93 94typedef struct Struct_Name_Entry { 95 STAILQ_ENTRY(Struct_Name_Entry) link; 96 char name[1]; 97} Name_Entry; 98 99/* Lock object */ 100typedef struct Struct_LockInfo { 101 void *context; /* Client context for creating locks */ 102 void *thelock; /* The one big lock */ 103 /* Debugging aids. */ 104 volatile int rcount; /* Number of readers holding lock */ 105 volatile int wcount; /* Number of writers holding lock */ 106 /* Methods */ 107 void *(*lock_create)(void *context); 108 void (*rlock_acquire)(void *lock); 109 void (*wlock_acquire)(void *lock); 110 void (*rlock_release)(void *lock); 111 void (*wlock_release)(void *lock); 112 void (*lock_destroy)(void *lock); 113 void (*context_destroy)(void *context); 114} LockInfo; 115 116typedef struct Struct_Ver_Entry { 117 Elf_Word hash; 118 unsigned int flags; 119 const char *name; 120 const char *file; 121} Ver_Entry; 122 123#define VER_INFO_HIDDEN 0x01 124 125/* 126 * Shared object descriptor. 127 * 128 * Items marked with "(%)" are dynamically allocated, and must be freed 129 * when the structure is destroyed. 130 * 131 * CAUTION: It appears that the JDK port peeks into these structures. 132 * It looks at "next" and "mapbase" at least. Don't add new members 133 * near the front, until this can be straightened out. 134 */ 135typedef struct Struct_Obj_Entry { 136 /* 137 * These two items have to be set right for compatibility with the 138 * original ElfKit crt1.o. 139 */ 140 Elf_Size magic; /* Magic number (sanity check) */ 141 Elf_Size version; /* Version number of struct format */ 142 143 struct Struct_Obj_Entry *next; 144 char *path; /* Pathname of underlying file (%) */ 145 char *origin_path; /* Directory path of origin file */ 146 int refcount; 147 int dl_refcount; /* Number of times loaded by dlopen */ 148 149 /* These items are computed by map_object() or by digest_phdr(). */ 150 caddr_t mapbase; /* Base address of mapped region */ 151 size_t mapsize; /* Size of mapped region in bytes */ 152 size_t textsize; /* Size of text segment in bytes */ 153 Elf_Addr vaddrbase; /* Base address in shared object file */ 154 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 155 const Elf_Dyn *dynamic; /* Dynamic section */ 156 caddr_t entry; /* Entry point */ 157 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 158 size_t phsize; /* Size of program header in bytes */ 159 const char *interp; /* Pathname of the interpreter, if any */ 160 Elf_Word stack_flags; 161 162 /* TLS information */ 163 int tlsindex; /* Index in DTV for this module */ 164 void *tlsinit; /* Base address of TLS init block */ 165 size_t tlsinitsize; /* Size of TLS init block for this module */ 166 size_t tlssize; /* Size of TLS block for this module */ 167 size_t tlsoffset; /* Offset of static TLS block for this module */ 168 size_t tlsalign; /* Alignment of static TLS block */ 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#ifdef __mips__ 184 Elf_Word local_gotno; /* Number of local GOT entries */ 185 Elf_Word symtabno; /* Number of dynamic symbols */ 186 Elf_Word gotsym; /* First dynamic symbol in GOT */ 187#endif 188 189 const Elf_Verneed *verneed; /* Required versions. */ 190 Elf_Word verneednum; /* Number of entries in verneed table */ 191 const Elf_Verdef *verdef; /* Provided versions. */ 192 Elf_Word verdefnum; /* Number of entries in verdef table */ 193 const Elf_Versym *versyms; /* Symbol versions table */ 194 195 const Elf_Hashelt *buckets; /* Hash table buckets array */ 196 unsigned long nbuckets; /* Number of buckets */ 197 const Elf_Hashelt *chains; /* Hash table chain array */ 198 unsigned long nchains; /* Number of chains */ 199 200 char *rpath; /* Search path specified in object */ 201 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 202 Needed_Entry *needed_filtees; 203 Needed_Entry *needed_aux_filtees; 204 205 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 206 know about. */ 207 Ver_Entry *vertab; /* Versions required /defined by this object */ 208 int vernum; /* Number of entries in vertab */ 209 210 Elf_Addr init; /* Initialization function to call */ 211 Elf_Addr fini; /* Termination function to call */ 212 213 bool mainprog : 1; /* True if this is the main program */ 214 bool rtld : 1; /* True if this is the dynamic linker */ 215 bool textrel : 1; /* True if there are relocations to text seg */ 216 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 217 bool bind_now : 1; /* True if all relocations should be made first */ 218 bool traced : 1; /* Already printed in ldd trace output */ 219 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 220 bool init_done : 1; /* Already have added object to init list */ 221 bool tls_done : 1; /* Already allocated offset for static TLS */ 222 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 223 bool z_origin : 1; /* Process rpath and soname tokens */ 224 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 225 bool z_noopen : 1; /* Do not load on dlopen */ 226 bool z_loadfltr : 1; /* Immediately load filtees */ 227 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 228 bool init_scanned: 1; /* Object is already on init list. */ 229 bool on_fini_list: 1; /* Object is already on fini list. */ 230 bool dag_inited : 1; /* Object has its DAG initialized. */ 231 bool filtees_loaded : 1; /* Filtees loaded */ 232 233 struct link_map linkmap; /* For GDB and dlinfo() */ 234 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 235 Objlist dagmembers; /* DAG has these members (%) */ 236 dev_t dev; /* Object's filesystem's device */ 237 ino_t ino; /* Object's inode number */ 238 void *priv; /* Platform-dependant */ 239} Obj_Entry; 240 241#define RTLD_MAGIC 0xd550b87a 242#define RTLD_VERSION 1 243 244#define RTLD_STATIC_TLS_EXTRA 128 245 246/* Flags to be passed into symlook_ family of functions. */ 247#define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 248#define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol. Used by 249 dlsym. */ 250 251/* Flags for load_object(). */ 252#define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 253#define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 254#define RTLD_LO_TRACE 0x04 /* Only tracing. */ 255#define RTLD_LO_NODELETE 0x08 /* Loaded object cannot be closed. */ 256#define RTLD_LO_FILTEES 0x10 /* Loading filtee. */ 257 258/* 259 * Symbol cache entry used during relocation to avoid multiple lookups 260 * of the same symbol. 261 */ 262typedef struct Struct_SymCache { 263 const Elf_Sym *sym; /* Symbol table entry */ 264 const Obj_Entry *obj; /* Shared object which defines it */ 265} SymCache; 266 267/* 268 * This structure provides a reentrant way to keep a list of objects and 269 * check which ones have already been processed in some way. 270 */ 271typedef struct Struct_DoneList { 272 const Obj_Entry **objs; /* Array of object pointers */ 273 unsigned int num_alloc; /* Allocated size of the array */ 274 unsigned int num_used; /* Number of array slots used */ 275} DoneList; 276 277struct Struct_RtldLockState { 278 int lockstate; 279 sigjmp_buf env; 280}; 281 282/* 283 * The pack of arguments and results for the symbol lookup functions. 284 */ 285typedef struct Struct_SymLook { 286 const char *name; 287 unsigned long hash; 288 const Ver_Entry *ventry; 289 int flags; 290 const Obj_Entry *defobj_out; 291 const Elf_Sym *sym_out; 292 struct Struct_RtldLockState *lockstate; 293} SymLook; 294 295extern void _rtld_error(const char *, ...) __printflike(1, 2); 296extern Obj_Entry *map_object(int, const char *, const struct stat *); 297extern void *xcalloc(size_t); 298extern void *xmalloc(size_t); 299extern char *xstrdup(const char *); 300extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 301extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 302 303extern void dump_relocations (Obj_Entry *); 304extern void dump_obj_relocations (Obj_Entry *); 305extern void dump_Elf_Rel (Obj_Entry *, const Elf_Rel *, u_long); 306extern void dump_Elf_Rela (Obj_Entry *, const Elf_Rela *, u_long); 307 308/* 309 * Function declarations. 310 */ 311unsigned long elf_hash(const char *); 312const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 313 const Obj_Entry **, int, SymCache *, struct Struct_RtldLockState *); 314void init_pltgot(Obj_Entry *); 315void lockdflt_init(void); 316void obj_free(Obj_Entry *); 317Obj_Entry *obj_new(void); 318void _rtld_bind_start(void); 319void symlook_init(SymLook *, const char *); 320int symlook_obj(SymLook *, const Obj_Entry *); 321void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 322void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 323void free_tls(void *, size_t, size_t); 324void *allocate_module_tls(int index); 325bool allocate_tls_offset(Obj_Entry *obj); 326void free_tls_offset(Obj_Entry *obj); 327const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 328 329/* 330 * MD function declarations. 331 */ 332int do_copy_relocations(Obj_Entry *); 333int reloc_non_plt(Obj_Entry *, Obj_Entry *, struct Struct_RtldLockState *); 334int reloc_plt(Obj_Entry *); 335int reloc_jmpslots(Obj_Entry *, struct Struct_RtldLockState *); 336void allocate_initial_tls(Obj_Entry *); 337 338#endif /* } */ 339