1 /*- 2 * Copyright 1996-1998 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 typedef struct Struct_Objlist_Entry { 56 STAILQ_ENTRY(Struct_Objlist_Entry) link; 57 struct Struct_Obj_Entry *obj; 58 } Objlist_Entry; 59 60 typedef STAILQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 61 62 typedef struct Struct_Needed_Entry { 63 struct Struct_Needed_Entry *next; 64 struct Struct_Obj_Entry *obj; 65 unsigned long name; /* Offset of name in string table */ 66 } Needed_Entry; 67 68 /* 69 * Shared object descriptor. 70 * 71 * Items marked with "(%)" are dynamically allocated, and must be freed 72 * when the structure is destroyed. 73 * 74 * CAUTION: It appears that the JDK port peeks into these structures. 75 * It looks at "next" and "mapbase" at least. Don't add new members 76 * near the front, until this can be straightened out. 77 */ 78 typedef struct Struct_Obj_Entry { 79 /* 80 * These two items have to be set right for compatibility with the 81 * original ElfKit crt1.o. 82 */ 83 Elf_Word magic; /* Magic number (sanity check) */ 84 Elf_Word version; /* Version number of struct format */ 85 86 struct Struct_Obj_Entry *next; 87 char *path; /* Pathname of underlying file (%) */ 88 int refcount; 89 int dl_refcount; /* Number of times loaded by dlopen */ 90 91 /* These items are computed by map_object() or by digest_phdr(). */ 92 caddr_t mapbase; /* Base address of mapped region */ 93 size_t mapsize; /* Size of mapped region in bytes */ 94 size_t textsize; /* Size of text segment in bytes */ 95 Elf_Addr vaddrbase; /* Base address in shared object file */ 96 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 97 const Elf_Dyn *dynamic; /* Dynamic section */ 98 caddr_t entry; /* Entry point */ 99 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 100 size_t phsize; /* Size of program header in bytes */ 101 const char *interp; /* Pathname of the interpreter, if any */ 102 103 /* Items from the dynamic section. */ 104 Elf_Addr *pltgot; /* PLT or GOT, depending on architecture */ 105 const Elf_Rel *rel; /* Relocation entries */ 106 unsigned long relsize; /* Size in bytes of relocation info */ 107 const Elf_Rela *rela; /* Relocation entries with addend */ 108 unsigned long relasize; /* Size in bytes of addend relocation info */ 109 const Elf_Rel *pltrel; /* PLT relocation entries */ 110 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 111 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 112 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 113 const Elf_Sym *symtab; /* Symbol table */ 114 const char *strtab; /* String table */ 115 unsigned long strsize; /* Size in bytes of string table */ 116 117 const Elf_Addr *buckets; /* Hash table buckets array */ 118 unsigned long nbuckets; /* Number of buckets */ 119 const Elf_Addr *chains; /* Hash table chain array */ 120 unsigned long nchains; /* Number of chains */ 121 122 const char *rpath; /* Search path specified in object */ 123 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 124 125 void (*init)(void); /* Initialization function to call */ 126 void (*fini)(void); /* Termination function to call */ 127 128 bool mainprog; /* True if this is the main program */ 129 bool rtld; /* True if this is the dynamic linker */ 130 bool textrel; /* True if there are relocations to text seg */ 131 bool symbolic; /* True if generated with "-Bsymbolic" */ 132 bool traced; /* Already printed in ldd trace output */ 133 134 struct link_map linkmap; /* for GDB */ 135 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 136 Objlist dagmembers; /* DAG has these members (%) */ 137 dev_t dev; /* Object's filesystem's device */ 138 ino_t ino; /* Object's inode number */ 139 unsigned long mark; /* Set to "curmark" to avoid repeat visits */ 140 } Obj_Entry; 141 142 #define RTLD_MAGIC 0xd550b87a 143 #define RTLD_VERSION 1 144 145 extern void _rtld_error(const char *, ...) __printflike(1, 2); 146 extern Obj_Entry *map_object(int, const char *, const struct stat *); 147 extern void *xcalloc(size_t); 148 extern void *xmalloc(size_t); 149 extern char *xstrdup(const char *); 150 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 151 152 /* 153 * Function declarations. 154 */ 155 int do_copy_relocations(Obj_Entry *); 156 unsigned long elf_hash(const char *); 157 const Elf_Sym *find_symdef(unsigned long, Obj_Entry *, const Obj_Entry **, 158 bool); 159 void init_pltgot(Obj_Entry *); 160 void obj_free(Obj_Entry *); 161 Obj_Entry *obj_new(void); 162 int reloc_non_plt(Obj_Entry *, Obj_Entry *); 163 int reloc_plt(Obj_Entry *, bool); 164 void _rtld_bind_start(void); 165 const Elf_Sym *symlook_obj(const char *, unsigned long, 166 const Obj_Entry *, bool); 167 168 #endif /* } */ 169