rtld.h revision 1.91
1 /* $NetBSD: rtld.h,v 1.91 2010/04/05 14:01:26 joerg 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 <stdbool.h> 39 #include <stddef.h> 40 #include <sys/param.h> 41 #include <sys/types.h> 42 #include <sys/queue.h> 43 #include <sys/exec_elf.h> 44 #include "rtldenv.h" 45 #include "link.h" 46 47 #if defined(_RTLD_SOURCE) 48 49 #ifndef RTLD_DEFAULT_LIBRARY_PATH 50 #define RTLD_DEFAULT_LIBRARY_PATH "/usr/lib" 51 #endif 52 #define _PATH_LD_HINTS "/etc/ld.so.conf" 53 54 extern size_t _rtld_pagesz; 55 56 #define round_down(x) ((x) & ~(_rtld_pagesz - 1)) 57 #define round_up(x) round_down((x) + _rtld_pagesz - 1) 58 59 #define NEW(type) ((type *) xmalloc(sizeof(type))) 60 #define CNEW(type) ((type *) xcalloc(sizeof(type))) 61 62 /* 63 * Fill in a DoneList with an allocation large enough to hold all of 64 * the currently-loaded objects. Keep this in a macro since it calls 65 * alloca and we want that to occur within the scope of the caller. 66 */ 67 #define _rtld_donelist_init(dlp) \ 68 ((dlp)->num_alloc = _rtld_objcount, \ 69 (dlp)->objs = alloca((dlp)->num_alloc * sizeof((dlp)->objs[0])), \ 70 assert((dlp)->objs != NULL), \ 71 (dlp)->num_used = 0) 72 73 #endif /* _RTLD_SOURCE */ 74 75 /* 76 * C++ has mandated the use of the following keywords for its new boolean 77 * type. We might as well follow their lead. 78 */ 79 struct Struct_Obj_Entry; 80 81 typedef struct Struct_Objlist_Entry { 82 SIMPLEQ_ENTRY(Struct_Objlist_Entry) link; 83 struct Struct_Obj_Entry *obj; 84 } Objlist_Entry; 85 86 typedef SIMPLEQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 87 88 typedef struct Struct_Needed_Entry { 89 struct Struct_Needed_Entry *next; 90 struct Struct_Obj_Entry *obj; 91 unsigned long name; /* Offset of name in string table */ 92 } Needed_Entry; 93 94 typedef struct _rtld_search_path_t { 95 struct _rtld_search_path_t *sp_next; 96 const char *sp_path; 97 size_t sp_pathlen; 98 } Search_Path; 99 100 101 #define RTLD_MAX_ENTRY 10 102 #define RTLD_MAX_LIBRARY 4 103 #define RTLD_MAX_CTL 2 104 typedef struct _rtld_library_xform_t { 105 struct _rtld_library_xform_t *next; 106 char *name; 107 const char *ctlname; 108 struct { 109 char *value; 110 char *library[RTLD_MAX_LIBRARY]; 111 } entry[RTLD_MAX_ENTRY]; 112 } Library_Xform; 113 114 /* 115 * Shared object descriptor. 116 * 117 * Items marked with "(%)" are dynamically allocated, and must be freed 118 * when the structure is destroyed. 119 */ 120 121 #define RTLD_MAGIC 0xd550b87a 122 #define RTLD_VERSION 1 123 #define RTLD_MAIN 0x800 124 125 typedef struct Struct_Obj_Entry { 126 Elf32_Word magic; /* Magic number (sanity check) */ 127 Elf32_Word version; /* Version number of struct format */ 128 129 struct Struct_Obj_Entry *next; 130 char *path; /* Pathname of underlying file (%) */ 131 int refcount; 132 int dl_refcount; /* Number of times loaded by dlopen */ 133 134 /* These items are computed by map_object() or by digest_phdr(). */ 135 caddr_t mapbase; /* Base address of mapped region */ 136 size_t mapsize; /* Size of mapped region in bytes */ 137 size_t textsize; /* Size of text segment in bytes */ 138 Elf_Addr vaddrbase; /* Base address in shared object file */ 139 caddr_t relocbase; /* Reloc const = mapbase - *vaddrbase */ 140 Elf_Dyn *dynamic; /* Dynamic section */ 141 caddr_t entry; /* Entry point */ 142 const Elf_Phdr *__junk001; 143 size_t pathlen; /* Pathname length */ 144 145 /* Items from the dynamic section. */ 146 Elf_Addr *pltgot; /* PLTGOT table */ 147 const Elf_Rel *rel; /* Relocation entries */ 148 const Elf_Rel *rellim; /* Limit of Relocation entries */ 149 const Elf_Rela *rela; /* Relocation entries */ 150 const Elf_Rela *relalim; /* Limit of Relocation entries */ 151 const Elf_Rel *pltrel; /* PLT relocation entries */ 152 const Elf_Rel *pltrellim; /* Limit of PLT relocation entries */ 153 const Elf_Rela *pltrela; /* PLT relocation entries */ 154 const Elf_Rela *pltrelalim; /* Limit of PLT relocation entries */ 155 const Elf_Sym *symtab; /* Symbol table */ 156 const char *strtab; /* String table */ 157 unsigned long strsize; /* Size in bytes of string table */ 158 #ifdef __mips__ 159 Elf_Word local_gotno; /* Number of local GOT entries */ 160 Elf_Word symtabno; /* Number of dynamic symbols */ 161 Elf_Word gotsym; /* First dynamic symbol in GOT */ 162 #endif 163 164 const Elf_Word *buckets; /* Hash table buckets array */ 165 uint32_t nbuckets; /* Number of buckets */ 166 uint32_t nbuckets_m; /* Precomputed for fast remainder */ 167 uint8_t nbuckets_s1; 168 uint8_t nbuckets_s2; 169 const Elf_Word *chains; /* Hash table chain array */ 170 unsigned long nchains; /* Number of chains */ 171 172 Search_Path *rpaths; /* Search path specified in object */ 173 Needed_Entry *needed; /* Shared objects needed by this (%) */ 174 175 void (*init)(void); /* Initialization function to call */ 176 void (*fini)(void); /* Termination function to call */ 177 178 /* Entry points for dlopen() and friends. */ 179 void *(*dlopen)(const char *, int); 180 void *(*dlsym)(void *, const char *); 181 char *(*dlerror)(void); 182 int (*dlclose)(void *); 183 int (*dladdr)(const void *, Dl_info *); 184 185 u_int32_t mainprog:1, /* True if this is the main program */ 186 rtld:1, /* True if this is the dynamic linker */ 187 textrel:1, /* True if there are relocations to 188 * text seg */ 189 symbolic:1, /* True if generated with 190 * "-Bsymbolic" */ 191 printed:1, /* True if ldd has printed it */ 192 isdynamic:1, /* True if this is a pure PIC object */ 193 mainref:1, /* True if on _rtld_list_main */ 194 globalref:1, /* True if on _rtld_list_global */ 195 init_done:1, /* True if .init has been added */ 196 init_called:1, /* True if .init function has been 197 * called */ 198 fini_called:1, /* True if .fini function has been 199 * called */ 200 initfirst:1; /* True if object's .init/.fini take 201 * priority over others */ 202 203 struct link_map linkmap; /* for GDB */ 204 205 /* These items are computed by map_object() or by digest_phdr(). */ 206 const char *interp; /* Pathname of the interpreter, if any */ 207 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 208 Objlist dagmembers; /* DAG has these members (%) */ 209 dev_t dev; /* Object's filesystem's device */ 210 ino_t ino; /* Object's inode number */ 211 212 void *ehdr; 213 } Obj_Entry; 214 215 typedef struct Struct_DoneList { 216 const Obj_Entry **objs; /* Array of object pointers */ 217 unsigned int num_alloc; /* Allocated size of the array */ 218 unsigned int num_used; /* Number of array slots used */ 219 } DoneList; 220 221 222 #if defined(_RTLD_SOURCE) 223 224 extern struct r_debug _rtld_debug; 225 extern Search_Path *_rtld_default_paths; 226 extern Obj_Entry *_rtld_objlist; 227 extern Obj_Entry **_rtld_objtail; 228 extern int _rtld_objcount; 229 extern Obj_Entry *_rtld_objmain; 230 extern Obj_Entry _rtld_objself; 231 extern Search_Path *_rtld_paths; 232 extern Library_Xform *_rtld_xforms; 233 extern bool _rtld_trust; 234 extern Objlist _rtld_list_global; 235 extern Objlist _rtld_list_main; 236 extern Elf_Sym _rtld_sym_zero; 237 238 /* rtld.c */ 239 240 /* 241 * We export these symbols using _rtld_symbol_lookup and is_exported. 242 */ 243 char *dlerror(void); 244 void *dlopen(const char *, int); 245 void *dlsym(void *, const char *); 246 int dlclose(void *); 247 int dladdr(const void *, Dl_info *); 248 int dlinfo(void *, int, void *); 249 250 void _rtld_error(const char *, ...) 251 __attribute__((__format__(__printf__,1,2))); 252 void _rtld_die(void) __attribute__((__noreturn__)); 253 void *_rtld_objmain_sym(const char *); 254 void _rtld_debug_state(void); 255 void _rtld_linkmap_add(Obj_Entry *); 256 void _rtld_linkmap_delete(Obj_Entry *); 257 void _rtld_objlist_push_head(Objlist *, Obj_Entry *); 258 void _rtld_objlist_push_tail(Objlist *, Obj_Entry *); 259 Objlist_Entry *_rtld_objlist_find(Objlist *, const Obj_Entry *); 260 261 /* expand.c */ 262 size_t _rtld_expand_path(char *, size_t, const char *, const char *,\ 263 const char *); 264 265 /* headers.c */ 266 void _rtld_digest_dynamic(const char *, Obj_Entry *); 267 Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t); 268 269 /* load.c */ 270 Obj_Entry *_rtld_load_object(const char *, int); 271 int _rtld_load_needed_objects(Obj_Entry *, int); 272 int _rtld_preload(const char *); 273 274 /* path.c */ 275 void _rtld_add_paths(const char *, Search_Path **, const char *); 276 void _rtld_process_hints(const char *, Search_Path **, Library_Xform **, 277 const char *); 278 int _rtld_sysctl(const char *, void *, size_t *); 279 280 /* reloc.c */ 281 int _rtld_do_copy_relocations(const Obj_Entry *); 282 int _rtld_relocate_objects(Obj_Entry *, bool); 283 int _rtld_relocate_nonplt_objects(const Obj_Entry *); 284 int _rtld_relocate_plt_lazy(const Obj_Entry *); 285 int _rtld_relocate_plt_objects(const Obj_Entry *); 286 void _rtld_setup_pltgot(const Obj_Entry *); 287 288 /* search.c */ 289 Obj_Entry *_rtld_load_library(const char *, const Obj_Entry *, int); 290 291 /* symbol.c */ 292 unsigned long _rtld_elf_hash(const char *); 293 const Elf_Sym *_rtld_symlook_obj(const char *, unsigned long, 294 const Obj_Entry *, bool); 295 const Elf_Sym *_rtld_find_symdef(unsigned long, const Obj_Entry *, 296 const Obj_Entry **, bool); 297 const Elf_Sym *_rtld_find_plt_symdef(unsigned long, const Obj_Entry *, 298 const Obj_Entry **, bool); 299 300 const Elf_Sym *_rtld_symlook_list(const char *, unsigned long, 301 const Objlist *, const Obj_Entry **, bool, DoneList *); 302 const Elf_Sym *_rtld_symlook_default(const char *, unsigned long, 303 const Obj_Entry *, const Obj_Entry **, bool); 304 const Elf_Sym *_rtld_symlook_needed(const char *, unsigned long, 305 const Needed_Entry *, const Obj_Entry **, bool, 306 DoneList *, DoneList *); 307 #ifdef COMBRELOC 308 void _rtld_combreloc_reset(const Obj_Entry *); 309 #endif 310 311 /* map_object.c */ 312 Obj_Entry *_rtld_map_object(const char *, int, const struct stat *); 313 void _rtld_obj_free(Obj_Entry *); 314 Obj_Entry *_rtld_obj_new(void); 315 316 /* function descriptors */ 317 #ifdef __HAVE_FUNCTION_DESCRIPTORS 318 Elf_Addr _rtld_function_descriptor_alloc(const Obj_Entry *, 319 const Elf_Sym *, Elf_Addr); 320 const void *_rtld_function_descriptor_function(const void *); 321 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 322 323 #endif /* _RTLD_SOURCE */ 324 325 #endif /* RTLD_H */ 326
Indexes created Wed Oct 01 15:09:59 GMT 2025