1 /* $NetBSD: rtld.h,v 1.65 2002/12/05 04:56:57 junyoung Exp $ */ 2 3 /* 4 * Copyright 1996 John D. Polstra. 5 * Copyright 1996 Matt Thomas <matt@3am-software.com> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. All advertising materials mentioning features or use of this software 17 * must display the following acknowledgement: 18 * This product includes software developed by John Polstra. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 */ 33 34 #ifndef RTLD_H 35 #define RTLD_H 36 37 #include <dlfcn.h> 38 #include <stddef.h> 39 #include <sys/param.h> 40 #include <sys/types.h> 41 #include <sys/queue.h> 42 #include <sys/exec_elf.h> 43 #include "rtldenv.h" 44 #include "link.h" 45 46 #if defined(_RTLD_SOURCE) 47 48 #ifndef RTLD_DEFAULT_LIBRARY_PATH 49 #define RTLD_DEFAULT_LIBRARY_PATH "/usr/lib" 50 #endif 51 #define _PATH_LD_HINTS "/etc/ld.so.conf" 52 53 extern int _rtld_pagesz; 54 55 #define round_down(x) ((x) & ~(_rtld_pagesz - 1)) 56 #define round_up(x) round_down((x) + _rtld_pagesz - 1) 57 58 #define NEW(type) ((type *) xmalloc(sizeof(type))) 59 #define CNEW(type) ((type *) xcalloc(sizeof(type))) 60 61 #endif /* _RTLD_SOURCE */ 62 63 /* 64 * C++ has mandated the use of the following keywords for its new boolean 65 * type. We might as well follow their lead. 66 */ 67 typedef enum { 68 false = 0, 69 true = 1 70 } bool; 71 72 struct Struct_Obj_Entry; 73 74 typedef struct Struct_Objlist_Entry { 75 SIMPLEQ_ENTRY(Struct_Objlist_Entry) link; 76 struct Struct_Obj_Entry *obj; 77 } Objlist_Entry; 78 79 typedef SIMPLEQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 80 81 typedef struct Struct_Needed_Entry { 82 struct Struct_Needed_Entry *next; 83 struct Struct_Obj_Entry *obj; 84 unsigned long name; /* Offset of name in string table */ 85 } Needed_Entry; 86 87 typedef struct _rtld_search_path_t { 88 struct _rtld_search_path_t *sp_next; 89 const char *sp_path; 90 size_t sp_pathlen; 91 } Search_Path; 92 93 94 #define RTLD_MAX_ENTRY 10 95 #define RTLD_MAX_LIBRARY 4 96 #define RTLD_MAX_CTL 2 97 typedef struct _rtld_library_xform_t { 98 struct _rtld_library_xform_t *next; 99 char *name; 100 int ctl[RTLD_MAX_CTL]; 101 int ctltype[RTLD_MAX_CTL]; 102 int ctlmax; 103 struct { 104 char *value; 105 char *library[RTLD_MAX_LIBRARY]; 106 } entry[RTLD_MAX_ENTRY]; 107 } Library_Xform; 108 109 /* 110 * Shared object descriptor. 111 * 112 * Items marked with "(%)" are dynamically allocated, and must be freed 113 * when the structure is destroyed. 114 */ 115 116 #define RTLD_MAGIC 0xd550b87a 117 #define RTLD_VERSION 1 118 #define RTLD_MAIN 0x800 119 120 typedef struct Struct_Obj_Entry { 121 Elf32_Word magic; /* Magic number (sanity check) */ 122 Elf32_Word version; /* Version number of struct format */ 123 124 struct Struct_Obj_Entry *next; 125 char *path; /* Pathname of underlying file (%) */ 126 int refcount; 127 int dl_refcount; /* Number of times loaded by dlopen */ 128 129 /* These items are computed by map_object() or by digest_phdr(). */ 130 caddr_t mapbase; /* Base address of mapped region */ 131 size_t mapsize; /* Size of mapped region in bytes */ 132 size_t textsize; /* Size of text segment in bytes */ 133 Elf_Addr vaddrbase; /* Base address in shared object file */ 134 caddr_t relocbase; /* Reloc const = mapbase - *vaddrbase */ 135 Elf_Dyn *dynamic; /* Dynamic section */ 136 caddr_t entry; /* Entry point */ 137 const Elf_Phdr *__junk001; 138 size_t pathlen; /* Pathname length */ 139 140 /* Items from the dynamic section. */ 141 Elf_Addr *pltgot; /* PLTGOT table */ 142 const Elf_Rel *rel; /* Relocation entries */ 143 const Elf_Rel *rellim; /* Limit of Relocation entries */ 144 const Elf_Rela *rela; /* Relocation entries */ 145 const Elf_Rela *relalim; /* Limit of Relocation entries */ 146 const Elf_Rel *pltrel; /* PLT relocation entries */ 147 const Elf_Rel *pltrellim; /* Limit of PLT relocation entries */ 148 const Elf_Rela *pltrela; /* PLT relocation entries */ 149 const Elf_Rela *pltrelalim; /* Limit of PLT relocation entries */ 150 const Elf_Sym *symtab; /* Symbol table */ 151 const char *strtab; /* String table */ 152 unsigned long strsize; /* Size in bytes of string table */ 153 #ifdef __mips__ 154 Elf_Word local_gotno; /* Number of local GOT entries */ 155 Elf_Word symtabno; /* Number of dynamic symbols */ 156 Elf_Word gotsym; /* First dynamic symbol in GOT */ 157 #endif 158 159 const Elf_Word *buckets; /* Hash table buckets array */ 160 unsigned long nbuckets; /* Number of buckets */ 161 const Elf_Word *chains; /* Hash table chain array */ 162 unsigned long nchains; /* Number of chains */ 163 164 Search_Path *rpaths; /* Search path specified in object */ 165 Needed_Entry *needed; /* Shared objects needed by this (%) */ 166 167 void (*init) /* Initialization function to call */ 168 __P((void)); 169 void (*fini) /* Termination function to call */ 170 __P((void)); 171 172 /* Entry points for dlopen() and friends. */ 173 void *(*dlopen) __P((const char *, int)); 174 void *(*dlsym) __P((void *, const char *)); 175 char *(*dlerror) __P((void)); 176 int (*dlclose) __P((void *)); 177 int (*dladdr) __P((const void *, Dl_info *)); 178 179 u_int32_t mainprog:1, /* True if this is the main program */ 180 rtld:1, /* True if this is the dynamic linker */ 181 textrel:1, /* True if there are relocations to 182 * text seg */ 183 symbolic:1, /* True if generated with 184 * "-Bsymbolic" */ 185 printed:1, /* True if ldd has printed it */ 186 isdynamic:1, /* True if this is a pure PIC object */ 187 mainref:1, /* True if on _rtld_list_main */ 188 globalref:1; /* True if on _rtld_list_global */ 189 190 struct link_map linkmap; /* for GDB */ 191 192 /* These items are computed by map_object() or by digest_phdr(). */ 193 const char *interp; /* Pathname of the interpreter, if any */ 194 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 195 Objlist dagmembers; /* DAG has these members (%) */ 196 dev_t dev; /* Object's filesystem's device */ 197 ino_t ino; /* Object's inode number */ 198 } Obj_Entry; 199 200 #if defined(_RTLD_SOURCE) 201 202 extern struct r_debug _rtld_debug; 203 extern Search_Path *_rtld_default_paths; 204 extern Obj_Entry *_rtld_objlist; 205 extern Obj_Entry **_rtld_objtail; 206 extern Obj_Entry *_rtld_objmain; 207 extern Obj_Entry _rtld_objself; 208 extern Search_Path *_rtld_paths; 209 extern Library_Xform *_rtld_xforms; 210 extern bool _rtld_trust; 211 extern Objlist _rtld_list_global; 212 extern Objlist _rtld_list_main; 213 extern Elf_Sym _rtld_sym_zero; 214 215 /* rtld.c */ 216 void _rtld_error __P((const char *, ...)) 217 __attribute__((__format__(__printf__,1,2))); 218 void _rtld_die __P((void)); 219 char *_rtld_dlerror __P((void)); 220 void *_rtld_dlopen __P((const char *, int)); 221 void *_rtld_objmain_sym __P((const char *)); 222 void *_rtld_dlsym __P((void *, const char *)); 223 int _rtld_dlclose __P((void *)); 224 int _rtld_dladdr __P((const void *, Dl_info *)); 225 void _rtld_debug_state __P((void)); 226 void _rtld_linkmap_add __P((Obj_Entry *)); 227 void _rtld_linkmap_delete __P((Obj_Entry *)); 228 void _rtld_objlist_add __P((Objlist *, Obj_Entry *)); 229 Objlist_Entry *_rtld_objlist_find __P((Objlist *, const Obj_Entry *)); 230 231 /* headers.c */ 232 void _rtld_digest_dynamic __P((Obj_Entry *)); 233 Obj_Entry *_rtld_digest_phdr __P((const Elf_Phdr *, int, caddr_t)); 234 235 /* load.c */ 236 Obj_Entry *_rtld_load_object __P((char *, int)); 237 int _rtld_load_needed_objects __P((Obj_Entry *, int)); 238 int _rtld_preload __P((const char *)); 239 240 /* path.c */ 241 void _rtld_add_paths __P((Search_Path **, const char *)); 242 void _rtld_process_hints __P((Search_Path **, Library_Xform **, const char *)); 243 244 /* reloc.c */ 245 int _rtld_do_copy_relocations __P((const Obj_Entry *)); 246 int _rtld_relocate_objects __P((Obj_Entry *, bool)); 247 int _rtld_relocate_nonplt_objects __P((const Obj_Entry *)); 248 int _rtld_relocate_plt_lazy __P((const Obj_Entry *)); 249 int _rtld_relocate_plt_objects __P((const Obj_Entry *)); 250 void _rtld_setup_pltgot __P((const Obj_Entry *)); 251 252 /* search.c */ 253 Obj_Entry *_rtld_load_library __P((const char *, const Obj_Entry *, int)); 254 255 /* symbol.c */ 256 unsigned long _rtld_elf_hash __P((const char *)); 257 const Elf_Sym *_rtld_symlook_obj __P((const char *, unsigned long, 258 const Obj_Entry *, bool)); 259 const Elf_Sym *_rtld_find_symdef __P((unsigned long, const Obj_Entry *, 260 const Obj_Entry **, bool)); 261 const Elf_Sym *_rtld_symlook_list(const char *, unsigned long, 262 const Objlist *, const Obj_Entry **, bool); 263 264 /* map_object.c */ 265 Obj_Entry *_rtld_map_object __P((char *, int, const struct stat *)); 266 void _rtld_obj_free(Obj_Entry *); 267 Obj_Entry *_rtld_obj_new(void); 268 269 /* function descriptors */ 270 #ifdef __HAVE_FUNCTION_DESCRIPTORS 271 Elf_Addr _rtld_function_descriptor_alloc __P((const Obj_Entry *, 272 const Elf_Sym *, Elf_Addr)); 273 const void *_rtld_function_descriptor_function __P((const void *)); 274 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 275 276 #endif /* _RTLD_SOURCE */ 277 278 #endif /* RTLD_H */ 279