rtld.h revision 116558
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 116558 2003-06-19 02:42:04Z mdodd $ 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#ifndef STANDARD_LIBRARY_PATH 43#define STANDARD_LIBRARY_PATH "/usr/lib" 44#endif 45 46#define NEW(type) ((type *) xmalloc(sizeof(type))) 47#define CNEW(type) ((type *) xcalloc(sizeof(type))) 48 49/* We might as well do booleans like C++. */ 50typedef unsigned char bool; 51#define false 0 52#define true 1 53 54struct stat; 55struct Struct_Obj_Entry; 56 57/* Lists of shared objects */ 58typedef struct Struct_Objlist_Entry { 59 STAILQ_ENTRY(Struct_Objlist_Entry) link; 60 struct Struct_Obj_Entry *obj; 61} Objlist_Entry; 62 63typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 64 65/* Types of init and fini functions */ 66typedef void (*InitFunc)(void); 67 68/* Lists of shared object dependencies */ 69typedef struct Struct_Needed_Entry { 70 struct Struct_Needed_Entry *next; 71 struct Struct_Obj_Entry *obj; 72 unsigned long name; /* Offset of name in string table */ 73} Needed_Entry; 74 75/* Lock object */ 76typedef struct Struct_LockInfo { 77 void *context; /* Client context for creating locks */ 78 void *thelock; /* The one big lock */ 79 /* Debugging aids. */ 80 volatile int rcount; /* Number of readers holding lock */ 81 volatile int wcount; /* Number of writers holding lock */ 82 /* Methods */ 83 void *(*lock_create)(void *context); 84 void (*rlock_acquire)(void *lock); 85 void (*wlock_acquire)(void *lock); 86 void (*rlock_release)(void *lock); 87 void (*wlock_release)(void *lock); 88 void (*lock_destroy)(void *lock); 89 void (*context_destroy)(void *context); 90} LockInfo; 91 92/* 93 * Shared object descriptor. 94 * 95 * Items marked with "(%)" are dynamically allocated, and must be freed 96 * when the structure is destroyed. 97 * 98 * CAUTION: It appears that the JDK port peeks into these structures. 99 * It looks at "next" and "mapbase" at least. Don't add new members 100 * near the front, until this can be straightened out. 101 */ 102typedef struct Struct_Obj_Entry { 103 /* 104 * These two items have to be set right for compatibility with the 105 * original ElfKit crt1.o. 106 */ 107 Elf_Word magic; /* Magic number (sanity check) */ 108 Elf_Word version; /* Version number of struct format */ 109 110 struct Struct_Obj_Entry *next; 111 char *path; /* Pathname of underlying file (%) */ 112 char *origin_path; /* Directory path of origin file */ 113 int refcount; 114 int dl_refcount; /* Number of times loaded by dlopen */ 115 116 /* These items are computed by map_object() or by digest_phdr(). */ 117 caddr_t mapbase; /* Base address of mapped region */ 118 size_t mapsize; /* Size of mapped region in bytes */ 119 size_t textsize; /* Size of text segment in bytes */ 120 Elf_Addr vaddrbase; /* Base address in shared object file */ 121 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 122 const Elf_Dyn *dynamic; /* Dynamic section */ 123 caddr_t entry; /* Entry point */ 124 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 125 size_t phsize; /* Size of program header in bytes */ 126 const char *interp; /* Pathname of the interpreter, if any */ 127 128 /* Items from the dynamic section. */ 129 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 130 const Elf_Rel *rel; /* Relocation entries */ 131 unsigned long relsize; /* Size in bytes of relocation info */ 132 const Elf_Rela *rela; /* Relocation entries with addend */ 133 unsigned long relasize; /* Size in bytes of addend relocation info */ 134 const Elf_Rel *pltrel; /* PLT relocation entries */ 135 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 136 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 137 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 138 const Elf_Sym *symtab; /* Symbol table */ 139 const char *strtab; /* String table */ 140 unsigned long strsize; /* Size in bytes of string table */ 141 142 const Elf_Hashelt *buckets; /* Hash table buckets array */ 143 unsigned long nbuckets; /* Number of buckets */ 144 const Elf_Hashelt *chains; /* Hash table chain array */ 145 unsigned long nchains; /* Number of chains */ 146 147 const char *rpath; /* Search path specified in object */ 148 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 149 150 Elf_Addr init; /* Initialization function to call */ 151 Elf_Addr fini; /* Termination function to call */ 152 153 bool mainprog; /* True if this is the main program */ 154 bool rtld; /* True if this is the dynamic linker */ 155 bool textrel; /* True if there are relocations to text seg */ 156 bool symbolic; /* True if generated with "-Bsymbolic" */ 157 bool bind_now; /* True if all relocations should be made first */ 158 bool traced; /* Already printed in ldd trace output */ 159 bool jmpslots_done; /* Already have relocated the jump slots */ 160 bool init_done; /* Already have added object to init list */ 161 162 struct link_map linkmap; /* for GDB and dlinfo() */ 163 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 164 Objlist dagmembers; /* DAG has these members (%) */ 165 dev_t dev; /* Object's filesystem's device */ 166 ino_t ino; /* Object's inode number */ 167 void *priv; /* Platform-dependant */ 168} Obj_Entry; 169 170#define RTLD_MAGIC 0xd550b87a 171#define RTLD_VERSION 1 172 173/* 174 * Symbol cache entry used during relocation to avoid multiple lookups 175 * of the same symbol. 176 */ 177typedef struct Struct_SymCache { 178 const Elf_Sym *sym; /* Symbol table entry */ 179 const Obj_Entry *obj; /* Shared object which defines it */ 180} SymCache; 181 182extern void _rtld_error(const char *, ...) __printflike(1, 2); 183extern Obj_Entry *map_object(int, const char *, const struct stat *); 184extern void *xcalloc(size_t); 185extern void *xmalloc(size_t); 186extern char *xstrdup(const char *); 187extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 188 189/* 190 * Function declarations. 191 */ 192unsigned long elf_hash(const char *); 193const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 194 const Obj_Entry **, bool, SymCache *); 195void init_pltgot(Obj_Entry *); 196void lockdflt_init(void); 197void obj_free(Obj_Entry *); 198Obj_Entry *obj_new(void); 199void _rtld_bind_start(void); 200const Elf_Sym *symlook_obj(const char *, unsigned long, 201 const Obj_Entry *, bool); 202 203/* 204 * MD function declarations. 205 */ 206int do_copy_relocations(Obj_Entry *); 207int reloc_non_plt(Obj_Entry *, Obj_Entry *); 208int reloc_plt(Obj_Entry *); 209int reloc_jmpslots(Obj_Entry *); 210 211#endif /* } */ 212