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 * $Id: rtld.h,v 1.4 1998/09/02 02:51:12 jdp Exp $ 26 */ 27 28 #ifndef RTLD_H /* { */ 29 #define RTLD_H 1 30 31 #include <sys/types.h> 32 33 #include <link.h> 34 #include <elf.h> 35 #include <stddef.h> 36 37 #ifndef STANDARD_LIBRARY_PATH 38 #define STANDARD_LIBRARY_PATH "/usr/lib/elf:/usr/lib" 39 #endif 40 41 #define NEW(type) ((type *) xmalloc(sizeof(type))) 42 #define CNEW(type) ((type *) xcalloc(sizeof(type))) 43 44 /* We might as well do booleans like C++. */ 45 typedef unsigned char bool; 46 #define false 0 47 #define true 1 48 49 struct Struct_Obj_Entry; 50 51 typedef struct Struct_Needed_Entry { 52 struct Struct_Needed_Entry *next; 53 struct Struct_Obj_Entry *obj; 54 unsigned long name; /* Offset of name in string table */ 55 } Needed_Entry; 56 57 /* 58 * Shared object descriptor. 59 * 60 * Items marked with "(%)" are dynamically allocated, and must be freed 61 * when the structure is destroyed. 62 */ 63 typedef struct Struct_Obj_Entry { 64 /* 65 * These two items have to be set right for compatibility with the 66 * original ElfKit crt1.o. 67 */ 68 Elf_Word magic; /* Magic number (sanity check) */ 69 Elf_Word version; /* Version number of struct format */ 70 71 struct Struct_Obj_Entry *next; 72 char *path; /* Pathname of underlying file (%) */ 73 int refcount; 74 int dl_refcount; /* Number of times loaded by dlopen */ 75 76 /* These items are computed by map_object() or by digest_phdr(). */ 77 caddr_t mapbase; /* Base address of mapped region */ 78 size_t mapsize; /* Size of mapped region in bytes */ 79 size_t textsize; /* Size of text segment in bytes */ 80 Elf_Addr vaddrbase; /* Base address in shared object file */ 81 caddr_t relocbase; /* Relocation constant = mapbase - vaddrbase */ 82 const Elf_Dyn *dynamic; /* Dynamic section */ 83 caddr_t entry; /* Entry point */ 84 const Elf_Phdr *phdr; /* Program header if it is mapped, else NULL */ 85 size_t phsize; /* Size of program header in bytes */ 86 87 /* Items from the dynamic section. */ 88 Elf_Addr *got; /* GOT table */ 89 const Elf_Rel *rel; /* Relocation entries */ 90 unsigned long relsize; /* Size in bytes of relocation info */ 91 const Elf_Rela *rela; /* Relocation entries with addend */ 92 unsigned long relasize; /* Size in bytes of addend relocation info */ 93 const Elf_Rel *pltrel; /* PLT relocation entries */ 94 unsigned long pltrelsize; /* Size in bytes of PLT relocation info */ 95 const Elf_Rela *pltrela; /* PLT relocation entries with addend */ 96 unsigned long pltrelasize; /* Size in bytes of PLT addend reloc info */ 97 const Elf_Sym *symtab; /* Symbol table */ 98 const char *strtab; /* String table */ 99 unsigned long strsize; /* Size in bytes of string table */ 100 101 const Elf_Addr *buckets; /* Hash table buckets array */ 102 unsigned long nbuckets; /* Number of buckets */ 103 const Elf_Addr *chains; /* Hash table chain array */ 104 unsigned long nchains; /* Number of chains */ 105 106 const char *rpath; /* Search path specified in object */ 107 Needed_Entry *needed; /* Shared objects needed by this one (%) */ 108 109 void (*init)(void); /* Initialization function to call */ 110 void (*fini)(void); /* Termination function to call */ 111 112 bool mainprog; /* True if this is the main program */ 113 bool rtld; /* True if this is the dynamic linker */ 114 bool textrel; /* True if there are relocations to text seg */ 115 bool symbolic; /* True if generated with "-Bsymbolic" */ 116 bool traced; /* Already printed in ldd trace output */ 117 118 struct link_map linkmap; /* for GDB */ 119 } Obj_Entry; 120 121 #define RTLD_MAGIC 0xd550b87a 122 #define RTLD_VERSION 1 123 124 extern void _rtld_error(const char *, ...); 125 extern Obj_Entry *map_object(int); 126 extern void *xcalloc(size_t); 127 extern void *xmalloc(size_t); 128 extern char *xstrdup(const char *); 129 extern Elf_Addr _GLOBAL_OFFSET_TABLE_[]; 130 131 /* 132 * Function declarations. 133 */ 134 int do_copy_relocations(Obj_Entry *); 135 int reloc_non_plt(Obj_Entry *, Obj_Entry *); 136 int reloc_plt(Obj_Entry *, bool); 137 unsigned long elf_hash(const char *); 138 const Elf_Sym *find_symdef(unsigned long, const Obj_Entry *, 139 const Obj_Entry **, bool); 140 const Elf_Sym *symlook_obj(const char *, unsigned long, 141 const Obj_Entry *, bool); 142 143 #endif /* } */ 144