rtld.h revision 1.73
1 /* $NetBSD: rtld.h,v 1.73 2006/05/22 19:49:09 drochner Exp $ */ 2 3 /* 4 * Copyright 1996 John D. Polstra. 5 * Copyright 1996 Matt Thomas <matt (at) 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 const char *ctlname; 101 struct { 102 char *value; 103 char *library[RTLD_MAX_LIBRARY]; 104 } entry[RTLD_MAX_ENTRY]; 105 } Library_Xform; 106 107 /* 108 * Shared object descriptor. 109 * 110 * Items marked with "(%)" are dynamically allocated, and must be freed 111 * when the structure is destroyed. 112 */ 113 114 #define RTLD_MAGIC 0xd550b87a 115 #define RTLD_VERSION 1 116 #define RTLD_MAIN 0x800 117 118 typedef struct Struct_Obj_Entry { 119 Elf32_Word magic; /* Magic number (sanity check) */ 120 Elf32_Word version; /* Version number of struct format */ 121 122 struct Struct_Obj_Entry *next; 123 char *path; /* Pathname of underlying file (%) */ 124 int refcount; 125 int dl_refcount; /* Number of times loaded by dlopen */ 126 127 /* These items are computed by map_object() or by digest_phdr(). */ 128 caddr_t mapbase; /* Base address of mapped region */ 129 size_t mapsize; /* Size of mapped region in bytes */ 130 size_t textsize; /* Size of text segment in bytes */ 131 Elf_Addr vaddrbase; /* Base address in shared object file */ 132 caddr_t relocbase; /* Reloc const = mapbase - *vaddrbase */ 133 Elf_Dyn *dynamic; /* Dynamic section */ 134 caddr_t entry; /* Entry point */ 135 const Elf_Phdr *__junk001; 136 size_t pathlen; /* Pathname length */ 137 138 /* Items from the dynamic section. */ 139 Elf_Addr *pltgot; /* PLTGOT table */ 140 const Elf_Rel *rel; /* Relocation entries */ 141 const Elf_Rel *rellim; /* Limit of Relocation entries */ 142 const Elf_Rela *rela; /* Relocation entries */ 143 const Elf_Rela *relalim; /* Limit of Relocation entries */ 144 const Elf_Rel *pltrel; /* PLT relocation entries */ 145 const Elf_Rel *pltrellim; /* Limit of PLT relocation entries */ 146 const Elf_Rela *pltrela; /* PLT relocation entries */ 147 const Elf_Rela *pltrelalim; /* Limit of PLT relocation entries */ 148 const Elf_Sym *symtab; /* Symbol table */ 149 const char *strtab; /* String table */ 150 unsigned long strsize; /* Size in bytes of string table */ 151 #ifdef __mips__ 152 Elf_Word local_gotno; /* Number of local GOT entries */ 153 Elf_Word symtabno; /* Number of dynamic symbols */ 154 Elf_Word gotsym; /* First dynamic symbol in GOT */ 155 #endif 156 157 const Elf_Word *buckets; /* Hash table buckets array */ 158 unsigned long nbuckets; /* Number of buckets */ 159 const Elf_Word *chains; /* Hash table chain array */ 160 unsigned long nchains; /* Number of chains */ 161 162 Search_Path *rpaths; /* Search path specified in object */ 163 Needed_Entry *needed; /* Shared objects needed by this (%) */ 164 165 void (*init)(void); /* Initialization function to call */ 166 void (*fini)(void); /* Termination function to call */ 167 168 /* Entry points for dlopen() and friends. */ 169 void *(*dlopen)(const char *, int); 170 void *(*dlsym)(void *, const char *); 171 char *(*dlerror)(void); 172 int (*dlclose)(void *); 173 int (*dladdr)(const void *, Dl_info *); 174 175 u_int32_t mainprog:1, /* True if this is the main program */ 176 rtld:1, /* True if this is the dynamic linker */ 177 textrel:1, /* True if there are relocations to 178 * text seg */ 179 symbolic:1, /* True if generated with 180 * "-Bsymbolic" */ 181 printed:1, /* True if ldd has printed it */ 182 isdynamic:1, /* True if this is a pure PIC object */ 183 mainref:1, /* True if on _rtld_list_main */ 184 globalref:1; /* True if on _rtld_list_global */ 185 186 struct link_map linkmap; /* for GDB */ 187 188 /* These items are computed by map_object() or by digest_phdr(). */ 189 const char *interp; /* Pathname of the interpreter, if any */ 190 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 191 Objlist dagmembers; /* DAG has these members (%) */ 192 dev_t dev; /* Object's filesystem's device */ 193 ino_t ino; /* Object's inode number */ 194 } Obj_Entry; 195 196 #if defined(_RTLD_SOURCE) 197 198 extern struct r_debug _rtld_debug; 199 extern Search_Path *_rtld_default_paths; 200 extern Obj_Entry *_rtld_objlist; 201 extern Obj_Entry **_rtld_objtail; 202 extern Obj_Entry *_rtld_objmain; 203 extern Obj_Entry _rtld_objself; 204 extern Search_Path *_rtld_paths; 205 extern Library_Xform *_rtld_xforms; 206 extern bool _rtld_trust; 207 extern Objlist _rtld_list_global; 208 extern Objlist _rtld_list_main; 209 extern Elf_Sym _rtld_sym_zero; 210 211 /* rtld.c */ 212 213 /* 214 * We export these symbols using _rtld_symbol_lookup and is_exported. 215 */ 216 char *dlerror(void); 217 void *dlopen(const char *, int); 218 void *dlsym(void *, const char *); 219 int dlclose(void *); 220 int dladdr(const void *, Dl_info *); 221 222 void _rtld_error(const char *, ...) 223 __attribute__((__format__(__printf__,1,2))); 224 void _rtld_die(void) __attribute__((__noreturn__)); 225 void *_rtld_objmain_sym(const char *); 226 void _rtld_debug_state(void); 227 void _rtld_linkmap_add(Obj_Entry *); 228 void _rtld_linkmap_delete(Obj_Entry *); 229 void _rtld_objlist_add(Objlist *, Obj_Entry *); 230 Objlist_Entry *_rtld_objlist_find(Objlist *, const Obj_Entry *); 231 232 /* headers.c */ 233 void _rtld_digest_dynamic(Obj_Entry *); 234 Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t); 235 236 /* load.c */ 237 Obj_Entry *_rtld_load_object(const char *, int); 238 int _rtld_load_needed_objects(Obj_Entry *, int); 239 int _rtld_preload(const char *); 240 241 /* path.c */ 242 void _rtld_add_paths(Search_Path **, const char *); 243 void _rtld_process_hints(Search_Path **, Library_Xform **, const char *); 244 int _rtld_sysctl(const char *, void *, size_t *); 245 246 /* reloc.c */ 247 int _rtld_do_copy_relocations(const Obj_Entry *); 248 int _rtld_relocate_objects(Obj_Entry *, bool); 249 int _rtld_relocate_nonplt_objects(const Obj_Entry *); 250 int _rtld_relocate_plt_lazy(const Obj_Entry *); 251 int _rtld_relocate_plt_objects(const Obj_Entry *); 252 void _rtld_setup_pltgot(const Obj_Entry *); 253 254 /* search.c */ 255 Obj_Entry *_rtld_load_library(const char *, const Obj_Entry *, int); 256 257 /* symbol.c */ 258 unsigned long _rtld_elf_hash(const char *); 259 const Elf_Sym *_rtld_symlook_obj(const char *, unsigned long, 260 const Obj_Entry *, bool); 261 const Elf_Sym *_rtld_find_symdef(unsigned long, const Obj_Entry *, 262 const Obj_Entry **, bool); 263 const Elf_Sym *_rtld_symlook_list(const char *, unsigned long, 264 const Objlist *, const Obj_Entry **, bool); 265 const Elf_Sym *_rtld_symlook_default(const char *, unsigned long, 266 const Obj_Entry *, const Obj_Entry **, bool); 267 268 /* map_object.c */ 269 Obj_Entry *_rtld_map_object(const char *, int, const struct stat *); 270 void _rtld_obj_free(Obj_Entry *); 271 Obj_Entry *_rtld_obj_new(void); 272 273 /* function descriptors */ 274 #ifdef __HAVE_FUNCTION_DESCRIPTORS 275 Elf_Addr _rtld_function_descriptor_alloc(const Obj_Entry *, 276 const Elf_Sym *, Elf_Addr); 277 const void *_rtld_function_descriptor_function(const void *); 278 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 279 280 #endif /* _RTLD_SOURCE */ 281 282 #endif /* RTLD_H */ 283
Indexes created Sun Sep 28 12:09:53 GMT 2025