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 * $FreeBSD$ 26 */ 27 28 #ifndef RTLD_H /* { */ 29 #define RTLD_H 1 30 31 #include <sys/types.h> 32 #include <sys/queue.h> 33 34 #include <link.h> 35 #include <elf.h> 36 #include <stddef.h> 37 38 #include "rtld_machdep.h" 39 40 #ifndef STANDARD_LIBRARY_PATH 41 #define STANDARD_LIBRARY_PATH "/usr/lib/elf:/usr/lib" 42 #endif 43 44 #define NEW(type) ((type *) xmalloc(sizeof(type))) 45 #define CNEW(type) ((type *) xcalloc(sizeof(type))) 46 47 /* We might as well do booleans like C++. */ 48 typedef unsigned char bool; 49 #define false 0 50 #define true 1 51 52 struct stat; 53 struct Struct_Obj_Entry; 54 55 /* Lists of shared objects */ 56 typedef struct Struct_Objlist_Entry { 57 STAILQ_ENTRY(Struct_Objlist_Entry) link; 58 struct Struct_Obj_Entry *obj; 59 } Objlist_Entry; 60 61 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 62 63 /* Types of init and fini functions */ 64 typedef void (*InitFunc)(void); 65 66 /* Lists of shared object dependencies */ 67 typedef struct Struct_Needed_Entry { 68 struct Struct_Needed_Entry *next; 69 struct Struct_Obj_Entry *obj; 70 unsigned long name; /* Offset of name in string table */ 71 } Needed_Entry; 72 73 /* Lock object */ 74 typedef struct Struct_LockInfo { 75 void *context; /* Client context for creating locks */ 76 void *thelock; /* The one big lock */ 77 /* Debugging aids. */ 78 volatile int rcount; /* Number of readers holding lock */ 79 volatile int wcount; /* Number of writers holding lock */ 80 /* Methods */ 81 void *(*lock_create)(void *context); 82 void (*rlock_acquire)(void *lock); 83 void (*wlock_acquire)(void *lock); 84 void (*rlock_release)(void *lock); 85 void (*wlock_release)(void *lock); 86 void (*lock_destroy)(void *lock); 87 void (*context_destroy)(void *context); 88 } LockInfo; 89 90 /* 91 * Shared object descriptor. 92 * 93 * Items marked with "(%)" are dynamically allocated, and must be freed 94 * when the structure is destroyed. 95 * 96 * CAUTION: It appears that the JDK port peeks into these structures. 97 * It looks at "next" and "mapbase" at least. Don't add new members 98 * near the front, until this can be straightened out. 99 */ 100 typedef struct Struct_Obj_Entry { 101 /* 102 * These two items have to be set right for compatibility with the 103 * original ElfKit crt1.o. 104 */ 105 Elf_Word magic; /* Magic number (sanity check) */ 106 Elf_Word version; /* Version number of struct format */ 107 108 struct Struct_Obj_Entry *next; 109 char *path; /* Pathname of underlying file (%) */ 110 int refcount; 111 int dl_refcount; /* Number of times loaded by dlopen */ 112 113 /* These items are computed by map_object() or by digest_phdr(). */ 114 caddr_t mapbase; /* Base address of mapped region */ 115 size_t mapsize; /* Size of mapped region in bytes */ 116 size_t textsize; /* Size of text segment in bytes */ 117 Elf_Addr vaddrbase; /* Base address in shared object file */ 118 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 119 const Elf_Dyn *dynamic; /* Dynamic section */ 120 caddr_t entry; /* Entry point */ 121 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 122 size_t phsize; /* Size of program header in bytes */ 123 const char *interp; /* Pathname of the interpreter, if any */ 124 125 /* Items from the dynamic section. */ 126 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 127 const Elf_Rel *rel; /* Relocation entries */ 128 unsigned long relsize; /* Size in bytes of relocation info */ 129 const Elf_Rela *rela; /* Relocation entries with addend */ 130 unsigned long relasize; /* Size in bytes of addend relocation info */ 131 const Elf_Rel *pltrel; /* PLT relocation entries */ 132 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 133 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 134 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 135 const Elf_Sym *symtab; /* Symbol table */ 136 const char *strtab; /* String table */ 137 unsigned long strsize; /* Size in bytes of string table */ 138 139 const Elf_Addr *buckets; /* Hash table buckets array */ 140 unsigned long nbuckets; /* Number of buckets */ 141 const Elf_Addr *chains; /* Hash table chain array */ 142 unsigned long nchains; /* Number of chains */ 143 144 const char *rpath; /* Search path specified in object */ 145 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 146 147 InitFunc init; /* Initialization function to call */ 148 InitFunc fini; /* Termination function to call */ 149 150 bool mainprog; /* True if this is the main program */ 151 bool rtld; /* True if this is the dynamic linker */ 152 bool textrel; /* True if there are relocations to text seg */ 153 bool symbolic; /* True if generated with "-Bsymbolic" */ 154 bool traced; /* Already printed in ldd trace output */ 155 bool jmpslots_done; /* Already have relocated the jump slots */ 156 bool init_done; /* Already have added object to init list */ 157 158 struct link_map linkmap; /* for GDB */ 159 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 160 Objlist dagmembers; /* DAG has these members (%) */ 161 dev_t dev; /* Object's filesystem's device */ 162 ino_t ino; /* Object's inode number */ 163 } Obj_Entry; 164 165 #define RTLD_MAGIC 0xd550b87a 166 #define RTLD_VERSION 1 167 168 extern void _rtld_error(const char *, ...) __printflike(1, 2); 169 extern Obj_Entry *map_object(int, const char *, const struct stat *); 170 extern void *xcalloc(size_t); 171 extern void *xmalloc(size_t); 172 extern char *xstrdup(const char *); 173 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 174 175 /* 176 * Function declarations. 177 */ 178 int do_copy_relocations(Obj_Entry *); 179 unsigned long elf_hash(const char *); 180 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 181 const Obj_Entry **, bool); 182 void init_pltgot(Obj_Entry *); 183 void lockdflt_init(LockInfo *); 184 void obj_free(Obj_Entry *); 185 Obj_Entry *obj_new(void); 186 int reloc_non_plt(Obj_Entry *, Obj_Entry *); 187 int reloc_plt(Obj_Entry *); 188 int reloc_jmpslots(Obj_Entry *); 189 void _rtld_bind_start(void); 190 const Elf_Sym *symlook_obj(const char *, unsigned long, 191 const Obj_Entry *, bool); 192 193 #endif /* } */ 194