rtld.h revision 85004
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 85004 2001-10-15 18:48:42Z 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_machdep.h" 40 41#ifndef STANDARD_LIBRARY_PATH 42#define STANDARD_LIBRARY_PATH "/usr/lib/elf:/usr/lib" 43#endif 44 45#define NEW(type) ((type *) xmalloc(sizeof(type))) 46#define CNEW(type) ((type *) xcalloc(sizeof(type))) 47 48/* We might as well do booleans like C++. */ 49typedef unsigned char bool; 50#define false 0 51#define true 1 52 53struct stat; 54struct Struct_Obj_Entry; 55 56/* Lists of shared objects */ 57typedef struct Struct_Objlist_Entry { 58 STAILQ_ENTRY(Struct_Objlist_Entry) link; 59 struct Struct_Obj_Entry *obj; 60} Objlist_Entry; 61 62typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 63 64/* Types of init and fini functions */ 65typedef void (*InitFunc)(void); 66 67/* Lists of shared object dependencies */ 68typedef struct Struct_Needed_Entry { 69 struct Struct_Needed_Entry *next; 70 struct Struct_Obj_Entry *obj; 71 unsigned long name; /* Offset of name in string table */ 72} Needed_Entry; 73 74/* Lock object */ 75typedef struct Struct_LockInfo { 76 void *context; /* Client context for creating locks */ 77 void *thelock; /* The one big lock */ 78 /* Debugging aids. */ 79 volatile int rcount; /* Number of readers holding lock */ 80 volatile int wcount; /* Number of writers holding lock */ 81 /* Methods */ 82 void *(*lock_create)(void *context); 83 void (*rlock_acquire)(void *lock); 84 void (*wlock_acquire)(void *lock); 85 void (*rlock_release)(void *lock); 86 void (*wlock_release)(void *lock); 87 void (*lock_destroy)(void *lock); 88 void (*context_destroy)(void *context); 89} LockInfo; 90 91/* 92 * Shared object descriptor. 93 * 94 * Items marked with "(%)" are dynamically allocated, and must be freed 95 * when the structure is destroyed. 96 * 97 * CAUTION: It appears that the JDK port peeks into these structures. 98 * It looks at "next" and "mapbase" at least. Don't add new members 99 * near the front, until this can be straightened out. 100 */ 101typedef struct Struct_Obj_Entry { 102 /* 103 * These two items have to be set right for compatibility with the 104 * original ElfKit crt1.o. 105 */ 106 Elf_Word magic; /* Magic number (sanity check) */ 107 Elf_Word version; /* Version number of struct format */ 108 109 struct Struct_Obj_Entry *next; 110 char *path; /* Pathname of underlying file (%) */ 111 int refcount; 112 int dl_refcount; /* Number of times loaded by dlopen */ 113 114 /* These items are computed by map_object() or by digest_phdr(). */ 115 caddr_t mapbase; /* Base address of mapped region */ 116 size_t mapsize; /* Size of mapped region in bytes */ 117 size_t textsize; /* Size of text segment in bytes */ 118 Elf_Addr vaddrbase; /* Base address in shared object file */ 119 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 120 const Elf_Dyn *dynamic; /* Dynamic section */ 121 caddr_t entry; /* Entry point */ 122 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 123 size_t phsize; /* Size of program header in bytes */ 124 const char *interp; /* Pathname of the interpreter, if any */ 125 126 /* Items from the dynamic section. */ 127 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 128 const Elf_Rel *rel; /* Relocation entries */ 129 unsigned long relsize; /* Size in bytes of relocation info */ 130 const Elf_Rela *rela; /* Relocation entries with addend */ 131 unsigned long relasize; /* Size in bytes of addend relocation info */ 132 const Elf_Rel *pltrel; /* PLT relocation entries */ 133 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 134 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 135 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 136 const Elf_Sym *symtab; /* Symbol table */ 137 const char *strtab; /* String table */ 138 unsigned long strsize; /* Size in bytes of string table */ 139 140 const Elf_Hashelt *buckets; /* Hash table buckets array */ 141 unsigned long nbuckets; /* Number of buckets */ 142 const Elf_Hashelt *chains; /* Hash table chain array */ 143 unsigned long nchains; /* Number of chains */ 144 145 const char *rpath; /* Search path specified in object */ 146 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 147 148 InitFunc init; /* Initialization function to call */ 149 InitFunc fini; /* Termination function to call */ 150 151 bool mainprog; /* True if this is the main program */ 152 bool rtld; /* True if this is the dynamic linker */ 153 bool textrel; /* True if there are relocations to text seg */ 154 bool symbolic; /* True if generated with "-Bsymbolic" */ 155 bool traced; /* Already printed in ldd trace output */ 156 bool jmpslots_done; /* Already have relocated the jump slots */ 157 bool init_done; /* Already have added object to init list */ 158 159 struct link_map linkmap; /* for GDB */ 160 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 161 Objlist dagmembers; /* DAG has these members (%) */ 162 dev_t dev; /* Object's filesystem's device */ 163 ino_t ino; /* Object's inode number */ 164 void *priv; /* Platform-dependant */ 165} Obj_Entry; 166 167#define RTLD_MAGIC 0xd550b87a 168#define RTLD_VERSION 1 169 170/* 171 * Symbol cache entry used during relocation to avoid multiple lookups 172 * of the same symbol. 173 */ 174typedef struct Struct_SymCache { 175 const Elf_Sym *sym; /* Symbol table entry */ 176 const Obj_Entry *obj; /* Shared object which defines it */ 177} SymCache; 178 179extern void _rtld_error(const char *, ...) __printflike(1, 2); 180extern Obj_Entry *map_object(int, const char *, const struct stat *); 181extern void *xcalloc(size_t); 182extern void *xmalloc(size_t); 183extern char *xstrdup(const char *); 184extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 185 186/* 187 * Function declarations. 188 */ 189int do_copy_relocations(Obj_Entry *); 190unsigned long elf_hash(const char *); 191const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 192 const Obj_Entry **, bool, SymCache *); 193void init_pltgot(Obj_Entry *); 194void lockdflt_init(LockInfo *); 195void obj_free(Obj_Entry *); 196Obj_Entry *obj_new(void); 197int reloc_non_plt(Obj_Entry *, Obj_Entry *); 198int reloc_plt(Obj_Entry *); 199int reloc_jmpslots(Obj_Entry *); 200void _rtld_bind_start(void); 201const Elf_Sym *symlook_obj(const char *, unsigned long, 202 const Obj_Entry *, bool); 203 204#endif /* } */ 205