rtld.h revision 142645
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 142645 2005-02-27 12:55:40Z dfr $ 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 93/* Lock object */ 94typedef struct Struct_LockInfo { 95 void *context; /* Client context for creating locks */ 96 void *thelock; /* The one big lock */ 97 /* Debugging aids. */ 98 volatile int rcount; /* Number of readers holding lock */ 99 volatile int wcount; /* Number of writers holding lock */ 100 /* Methods */ 101 void *(*lock_create)(void *context); 102 void (*rlock_acquire)(void *lock); 103 void (*wlock_acquire)(void *lock); 104 void (*rlock_release)(void *lock); 105 void (*wlock_release)(void *lock); 106 void (*lock_destroy)(void *lock); 107 void (*context_destroy)(void *context); 108} LockInfo; 109 110/* 111 * Shared object descriptor. 112 * 113 * Items marked with "(%)" are dynamically allocated, and must be freed 114 * when the structure is destroyed. 115 * 116 * CAUTION: It appears that the JDK port peeks into these structures. 117 * It looks at "next" and "mapbase" at least. Don't add new members 118 * near the front, until this can be straightened out. 119 */ 120typedef struct Struct_Obj_Entry { 121 /* 122 * These two items have to be set right for compatibility with the 123 * original ElfKit crt1.o. 124 */ 125 Elf_Word magic; /* Magic number (sanity check) */ 126 Elf_Word version; /* Version number of struct format */ 127 128 struct Struct_Obj_Entry *next; 129 char *path; /* Pathname of underlying file (%) */ 130 char *origin_path; /* Directory path of origin file */ 131 int refcount; 132 int dl_refcount; /* Number of times loaded by dlopen */ 133 134 /* These items are computed by map_object() or by digest_phdr(). */ 135 caddr_t mapbase; /* Base address of mapped region */ 136 size_t mapsize; /* Size of mapped region in bytes */ 137 size_t textsize; /* Size of text segment in bytes */ 138 Elf_Addr vaddrbase; /* Base address in shared object file */ 139 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 140 const Elf_Dyn *dynamic; /* Dynamic section */ 141 caddr_t entry; /* Entry point */ 142 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 143 size_t phsize; /* Size of program header in bytes */ 144 const char *interp; /* Pathname of the interpreter, if any */ 145 146 /* TLS information */ 147 int tlsindex; /* Index in DTV for this module */ 148 void *tlsinit; /* Base address of TLS init block */ 149 size_t tlsinitsize; /* Size of TLS init block for this module */ 150 size_t tlssize; /* Size of TLS block for this module */ 151 size_t tlsoffset; /* Offset of static TLS block for this module */ 152 size_t tlsalign; /* Alignment of static TLS block */ 153 154 /* Items from the dynamic section. */ 155 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 156 const Elf_Rel *rel; /* Relocation entries */ 157 unsigned long relsize; /* Size in bytes of relocation info */ 158 const Elf_Rela *rela; /* Relocation entries with addend */ 159 unsigned long relasize; /* Size in bytes of addend relocation info */ 160 const Elf_Rel *pltrel; /* PLT relocation entries */ 161 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 162 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 163 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 164 const Elf_Sym *symtab; /* Symbol table */ 165 const char *strtab; /* String table */ 166 unsigned long strsize; /* Size in bytes of string table */ 167 168 const Elf_Hashelt *buckets; /* Hash table buckets array */ 169 unsigned long nbuckets; /* Number of buckets */ 170 const Elf_Hashelt *chains; /* Hash table chain array */ 171 unsigned long nchains; /* Number of chains */ 172 173 const char *rpath; /* Search path specified in object */ 174 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 175 176 Elf_Addr init; /* Initialization function to call */ 177 Elf_Addr fini; /* Termination function to call */ 178 179 bool mainprog; /* True if this is the main program */ 180 bool rtld; /* True if this is the dynamic linker */ 181 bool textrel; /* True if there are relocations to text seg */ 182 bool symbolic; /* True if generated with "-Bsymbolic" */ 183 bool bind_now; /* True if all relocations should be made first */ 184 bool traced; /* Already printed in ldd trace output */ 185 bool jmpslots_done; /* Already have relocated the jump slots */ 186 bool init_done; /* Already have added object to init list */ 187 bool tls_done; /* Already allocated offset for static TLS */ 188 189 struct link_map linkmap; /* for GDB and dlinfo() */ 190 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 191 Objlist dagmembers; /* DAG has these members (%) */ 192 dev_t dev; /* Object's filesystem's device */ 193 ino_t ino; /* Object's inode number */ 194 void *priv; /* Platform-dependant */ 195} Obj_Entry; 196 197#define RTLD_MAGIC 0xd550b87a 198#define RTLD_VERSION 1 199 200#define RTLD_STATIC_TLS_EXTRA 64 201 202/* 203 * Symbol cache entry used during relocation to avoid multiple lookups 204 * of the same symbol. 205 */ 206typedef struct Struct_SymCache { 207 const Elf_Sym *sym; /* Symbol table entry */ 208 const Obj_Entry *obj; /* Shared object which defines it */ 209} SymCache; 210 211extern void _rtld_error(const char *, ...) __printflike(1, 2); 212extern Obj_Entry *map_object(int, const char *, const struct stat *); 213extern void *xcalloc(size_t); 214extern void *xmalloc(size_t); 215extern char *xstrdup(const char *); 216extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 217 218extern void dump_relocations (Obj_Entry *); 219extern void dump_obj_relocations (Obj_Entry *); 220extern void dump_Elf_Rel (Obj_Entry *, const Elf_Rel *, u_long); 221extern void dump_Elf_Rela (Obj_Entry *, const Elf_Rela *, u_long); 222 223/* 224 * Function declarations. 225 */ 226unsigned long elf_hash(const char *); 227const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 228 const Obj_Entry **, bool, SymCache *); 229void init_pltgot(Obj_Entry *); 230void lockdflt_init(void); 231void obj_free(Obj_Entry *); 232Obj_Entry *obj_new(void); 233void _rtld_bind_start(void); 234const Elf_Sym *symlook_obj(const char *, unsigned long, 235 const Obj_Entry *, bool); 236void *tls_get_addr_common(Elf_Addr** dtvp, int index, size_t offset); 237void *allocate_tls(Obj_Entry *, void *, size_t, size_t); 238void free_tls(void *, size_t, size_t); 239void *allocate_module_tls(int index); 240bool allocate_tls_offset(Obj_Entry *obj); 241void free_tls_offset(Obj_Entry *obj); 242 243/* 244 * MD function declarations. 245 */ 246int do_copy_relocations(Obj_Entry *); 247int reloc_non_plt(Obj_Entry *, Obj_Entry *); 248int reloc_plt(Obj_Entry *); 249int reloc_jmpslots(Obj_Entry *); 250void allocate_initial_tls(Obj_Entry *); 251 252#endif /* } */ 253