rtld.h revision 212497
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 212497 2010-09-12 17:04:51Z nwhitehorn $ 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 <stddef.h> 38 39#include "rtld_lock.h" 40#include "rtld_machdep.h" 41 42#ifdef COMPAT_32BIT 43#undef STANDARD_LIBRARY_PATH 44#undef _PATH_ELF_HINTS 45#define _PATH_ELF_HINTS "/var/run/ld-elf32.so.hints" 46/* For running 32 bit binaries */ 47#define STANDARD_LIBRARY_PATH "/lib32:/usr/lib32" 48#define LD_ "LD_32_" 49#endif 50 51#ifndef STANDARD_LIBRARY_PATH 52#define STANDARD_LIBRARY_PATH "/lib:/usr/lib" 53#endif 54#ifndef LD_ 55#define LD_ "LD_" 56#endif 57 58#define NEW(type) ((type *) xmalloc(sizeof(type))) 59#define CNEW(type) ((type *) xcalloc(sizeof(type))) 60 61/* We might as well do booleans like C++. */ 62typedef unsigned char bool; 63#define false 0 64#define true 1 65 66extern size_t tls_last_offset; 67extern size_t tls_last_size; 68extern size_t tls_static_space; 69extern int tls_dtv_generation; 70extern int tls_max_index; 71 72struct stat; 73struct Struct_Obj_Entry; 74 75/* Lists of shared objects */ 76typedef struct Struct_Objlist_Entry { 77 STAILQ_ENTRY(Struct_Objlist_Entry) link; 78 struct Struct_Obj_Entry *obj; 79} Objlist_Entry; 80 81typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 82 83/* Types of init and fini functions */ 84typedef void (*InitFunc)(void); 85 86/* Lists of shared object dependencies */ 87typedef struct Struct_Needed_Entry { 88 struct Struct_Needed_Entry *next; 89 struct Struct_Obj_Entry *obj; 90 unsigned long name; /* Offset of name in string table */ 91} Needed_Entry; 92 93typedef struct Struct_Name_Entry { 94 STAILQ_ENTRY(Struct_Name_Entry) link; 95 char name[1]; 96} Name_Entry; 97 98/* Lock object */ 99typedef struct Struct_LockInfo { 100 void *context; /* Client context for creating locks */ 101 void *thelock; /* The one big lock */ 102 /* Debugging aids. */ 103 volatile int rcount; /* Number of readers holding lock */ 104 volatile int wcount; /* Number of writers holding lock */ 105 /* Methods */ 106 void *(*lock_create)(void *context); 107 void (*rlock_acquire)(void *lock); 108 void (*wlock_acquire)(void *lock); 109 void (*rlock_release)(void *lock); 110 void (*wlock_release)(void *lock); 111 void (*lock_destroy)(void *lock); 112 void (*context_destroy)(void *context); 113} LockInfo; 114 115typedef struct Struct_Ver_Entry { 116 Elf_Word hash; 117 unsigned int flags; 118 const char *name; 119 const char *file; 120} Ver_Entry; 121 122#define VER_INFO_HIDDEN 0x01 123 124/* 125 * Shared object descriptor. 126 * 127 * Items marked with "(%)" are dynamically allocated, and must be freed 128 * when the structure is destroyed. 129 * 130 * CAUTION: It appears that the JDK port peeks into these structures. 131 * It looks at "next" and "mapbase" at least. Don't add new members 132 * near the front, until this can be straightened out. 133 */ 134typedef struct Struct_Obj_Entry { 135 /* 136 * These two items have to be set right for compatibility with the 137 * original ElfKit crt1.o. 138 */ 139 Elf_Size magic; /* Magic number (sanity check) */ 140 Elf_Size version; /* Version number of struct format */ 141 142 struct Struct_Obj_Entry *next; 143 char *path; /* Pathname of underlying file (%) */ 144 char *origin_path; /* Directory path of origin file */ 145 int refcount; 146 int dl_refcount; /* Number of times loaded by dlopen */ 147 148 /* These items are computed by map_object() or by digest_phdr(). */ 149 caddr_t mapbase; /* Base address of mapped region */ 150 size_t mapsize; /* Size of mapped region in bytes */ 151 size_t textsize; /* Size of text segment in bytes */ 152 Elf_Addr vaddrbase; /* Base address in shared object file */ 153 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 154 const Elf_Dyn *dynamic; /* Dynamic section */ 155 caddr_t entry; /* Entry point */ 156 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 157 size_t phsize; /* Size of program header in bytes */ 158 const char *interp; /* Pathname of the interpreter, if any */ 159 160 /* TLS information */ 161 int tlsindex; /* Index in DTV for this module */ 162 void *tlsinit; /* Base address of TLS init block */ 163 size_t tlsinitsize; /* Size of TLS init block for this module */ 164 size_t tlssize; /* Size of TLS block for this module */ 165 size_t tlsoffset; /* Offset of static TLS block for this module */ 166 size_t tlsalign; /* Alignment of static TLS block */ 167 168 /* Items from the dynamic section. */ 169 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 170 const Elf_Rel *rel; /* Relocation entries */ 171 unsigned long relsize; /* Size in bytes of relocation info */ 172 const Elf_Rela *rela; /* Relocation entries with addend */ 173 unsigned long relasize; /* Size in bytes of addend relocation info */ 174 const Elf_Rel *pltrel; /* PLT relocation entries */ 175 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 176 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 177 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 178 const Elf_Sym *symtab; /* Symbol table */ 179 const char *strtab; /* String table */ 180 unsigned long strsize; /* Size in bytes of string table */ 181#ifdef __mips__ 182 Elf_Word local_gotno; /* Number of local GOT entries */ 183 Elf_Word symtabno; /* Number of dynamic symbols */ 184 Elf_Word gotsym; /* First dynamic symbol in GOT */ 185#endif 186 187 const Elf_Verneed *verneed; /* Required versions. */ 188 Elf_Word verneednum; /* Number of entries in verneed table */ 189 const Elf_Verdef *verdef; /* Provided versions. */ 190 Elf_Word verdefnum; /* Number of entries in verdef table */ 191 const Elf_Versym *versyms; /* Symbol versions table */ 192 193 const Elf_Hashelt *buckets; /* Hash table buckets array */ 194 unsigned long nbuckets; /* Number of buckets */ 195 const Elf_Hashelt *chains; /* Hash table chain array */ 196 unsigned long nchains; /* Number of chains */ 197 198 char *rpath; /* Search path specified in object */ 199 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 200 201 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 202 know about. */ 203 Ver_Entry *vertab; /* Versions required /defined by this object */ 204 int vernum; /* Number of entries in vertab */ 205 206 Elf_Addr init; /* Initialization function to call */ 207 Elf_Addr fini; /* Termination function to call */ 208 209 bool mainprog : 1; /* True if this is the main program */ 210 bool rtld : 1; /* True if this is the dynamic linker */ 211 bool textrel : 1; /* True if there are relocations to text seg */ 212 bool symbolic : 1; /* True if generated with "-Bsymbolic" */ 213 bool bind_now : 1; /* True if all relocations should be made first */ 214 bool traced : 1; /* Already printed in ldd trace output */ 215 bool jmpslots_done : 1; /* Already have relocated the jump slots */ 216 bool init_done : 1; /* Already have added object to init list */ 217 bool tls_done : 1; /* Already allocated offset for static TLS */ 218 bool phdr_alloc : 1; /* Phdr is allocated and needs to be freed. */ 219 bool z_origin : 1; /* Process rpath and soname tokens */ 220 bool z_nodelete : 1; /* Do not unload the object and dependencies */ 221 bool z_noopen : 1; /* Do not load on dlopen */ 222 bool ref_nodel : 1; /* Refcount increased to prevent dlclose */ 223 bool init_scanned: 1; /* Object is already on init list. */ 224 bool on_fini_list: 1; /* Object is already on fini list. */ 225 226 struct link_map linkmap; /* For GDB and dlinfo() */ 227 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 228 Objlist dagmembers; /* DAG has these members (%) */ 229 dev_t dev; /* Object's filesystem's device */ 230 ino_t ino; /* Object's inode number */ 231 void *priv; /* Platform-dependant */ 232} Obj_Entry; 233 234#define RTLD_MAGIC 0xd550b87a 235#define RTLD_VERSION 1 236 237#define RTLD_STATIC_TLS_EXTRA 128 238 239/* Flags to be passed into symlook_ family of functions. */ 240#define SYMLOOK_IN_PLT 0x01 /* Lookup for PLT symbol */ 241#define SYMLOOK_DLSYM 0x02 /* Return newes versioned symbol. Used by 242 dlsym. */ 243 244/* Flags for load_object(). */ 245#define RTLD_LO_NOLOAD 0x01 /* dlopen() specified RTLD_NOLOAD. */ 246#define RTLD_LO_DLOPEN 0x02 /* Load_object() called from dlopen(). */ 247#define RTLD_LO_TRACE 0x04 /* Only tracing. */ 248 249/* 250 * Symbol cache entry used during relocation to avoid multiple lookups 251 * of the same symbol. 252 */ 253typedef struct Struct_SymCache { 254 const Elf_Sym *sym; /* Symbol table entry */ 255 const Obj_Entry *obj; /* Shared object which defines it */ 256} SymCache; 257 258extern void _rtld_error(const char *, ...) __printflike(1, 2); 259extern Obj_Entry *map_object(int, const char *, const struct stat *); 260extern void *xcalloc(size_t); 261extern void *xmalloc(size_t); 262extern char *xstrdup(const char *); 263extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 264extern Elf_Sym sym_zero; /* For resolving undefined weak refs. */ 265 266extern void dump_relocations (Obj_Entry *); 267extern void dump_obj_relocations (Obj_Entry *); 268extern void dump_Elf_Rel (Obj_Entry *, const Elf_Rel *, u_long); 269extern void dump_Elf_Rela (Obj_Entry *, const Elf_Rela *, u_long); 270 271/* 272 * Function declarations. 273 */ 274unsigned long elf_hash(const char *); 275const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 276 const Obj_Entry **, int, SymCache *); 277void init_pltgot(Obj_Entry *); 278void lockdflt_init(void); 279void obj_free(Obj_Entry *); 280Obj_Entry *obj_new(void); 281void _rtld_bind_start(void); 282const Elf_Sym *symlook_obj(const char *, unsigned long, const Obj_Entry *, 283 const Ver_Entry *, int); 284void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 285void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 286void free_tls(void *, size_t, size_t); 287void *allocate_module_tls(int index); 288bool allocate_tls_offset(Obj_Entry *obj); 289void free_tls_offset(Obj_Entry *obj); 290const Ver_Entry *fetch_ventry(const Obj_Entry *obj, unsigned long); 291 292/* 293 * MD function declarations. 294 */ 295int do_copy_relocations(Obj_Entry *); 296int reloc_non_plt(Obj_Entry *, Obj_Entry *); 297int reloc_plt(Obj_Entry *); 298int reloc_jmpslots(Obj_Entry *); 299void allocate_initial_tls(Obj_Entry *); 300 301#endif /* } */ 302