rtld.h revision 1.90
1 /* $NetBSD: rtld.h,v 1.90 2010/03/18 22:17:55 roy 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 unsigned long nbuckets; /* Number of buckets */ 166 const Elf_Word *chains; /* Hash table chain array */ 167 unsigned long nchains; /* Number of chains */ 168 169 Search_Path *rpaths; /* Search path specified in object */ 170 Needed_Entry *needed; /* Shared objects needed by this (%) */ 171 172 void (*init)(void); /* Initialization function to call */ 173 void (*fini)(void); /* Termination function to call */ 174 175 /* Entry points for dlopen() and friends. */ 176 void *(*dlopen)(const char *, int); 177 void *(*dlsym)(void *, const char *); 178 char *(*dlerror)(void); 179 int (*dlclose)(void *); 180 int (*dladdr)(const void *, Dl_info *); 181 182 u_int32_t mainprog:1, /* True if this is the main program */ 183 rtld:1, /* True if this is the dynamic linker */ 184 textrel:1, /* True if there are relocations to 185 * text seg */ 186 symbolic:1, /* True if generated with 187 * "-Bsymbolic" */ 188 printed:1, /* True if ldd has printed it */ 189 isdynamic:1, /* True if this is a pure PIC object */ 190 mainref:1, /* True if on _rtld_list_main */ 191 globalref:1, /* True if on _rtld_list_global */ 192 init_done:1, /* True if .init has been added */ 193 init_called:1, /* True if .init function has been 194 * called */ 195 fini_called:1, /* True if .fini function has been 196 * called */ 197 initfirst:1; /* True if object's .init/.fini take 198 * priority over others */ 199 200 struct link_map linkmap; /* for GDB */ 201 202 /* These items are computed by map_object() or by digest_phdr(). */ 203 const char *interp; /* Pathname of the interpreter, if any */ 204 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 205 Objlist dagmembers; /* DAG has these members (%) */ 206 dev_t dev; /* Object's filesystem's device */ 207 ino_t ino; /* Object's inode number */ 208 209 void *ehdr; 210 } Obj_Entry; 211 212 typedef struct Struct_DoneList { 213 const Obj_Entry **objs; /* Array of object pointers */ 214 unsigned int num_alloc; /* Allocated size of the array */ 215 unsigned int num_used; /* Number of array slots used */ 216 } DoneList; 217 218 219 #if defined(_RTLD_SOURCE) 220 221 extern struct r_debug _rtld_debug; 222 extern Search_Path *_rtld_default_paths; 223 extern Obj_Entry *_rtld_objlist; 224 extern Obj_Entry **_rtld_objtail; 225 extern int _rtld_objcount; 226 extern Obj_Entry *_rtld_objmain; 227 extern Obj_Entry _rtld_objself; 228 extern Search_Path *_rtld_paths; 229 extern Library_Xform *_rtld_xforms; 230 extern bool _rtld_trust; 231 extern Objlist _rtld_list_global; 232 extern Objlist _rtld_list_main; 233 extern Elf_Sym _rtld_sym_zero; 234 235 /* rtld.c */ 236 237 /* 238 * We export these symbols using _rtld_symbol_lookup and is_exported. 239 */ 240 char *dlerror(void); 241 void *dlopen(const char *, int); 242 void *dlsym(void *, const char *); 243 int dlclose(void *); 244 int dladdr(const void *, Dl_info *); 245 int dlinfo(void *, int, void *); 246 247 void _rtld_error(const char *, ...) 248 __attribute__((__format__(__printf__,1,2))); 249 void _rtld_die(void) __attribute__((__noreturn__)); 250 void *_rtld_objmain_sym(const char *); 251 void _rtld_debug_state(void); 252 void _rtld_linkmap_add(Obj_Entry *); 253 void _rtld_linkmap_delete(Obj_Entry *); 254 void _rtld_objlist_push_head(Objlist *, Obj_Entry *); 255 void _rtld_objlist_push_tail(Objlist *, Obj_Entry *); 256 Objlist_Entry *_rtld_objlist_find(Objlist *, const Obj_Entry *); 257 258 /* expand.c */ 259 size_t _rtld_expand_path(char *, size_t, const char *, const char *,\ 260 const char *); 261 262 /* headers.c */ 263 void _rtld_digest_dynamic(const char *, Obj_Entry *); 264 Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t); 265 266 /* load.c */ 267 Obj_Entry *_rtld_load_object(const char *, int); 268 int _rtld_load_needed_objects(Obj_Entry *, int); 269 int _rtld_preload(const char *); 270 271 /* path.c */ 272 void _rtld_add_paths(const char *, Search_Path **, const char *); 273 void _rtld_process_hints(const char *, Search_Path **, Library_Xform **, 274 const char *); 275 int _rtld_sysctl(const char *, void *, size_t *); 276 277 /* reloc.c */ 278 int _rtld_do_copy_relocations(const Obj_Entry *); 279 int _rtld_relocate_objects(Obj_Entry *, bool); 280 int _rtld_relocate_nonplt_objects(const Obj_Entry *); 281 int _rtld_relocate_plt_lazy(const Obj_Entry *); 282 int _rtld_relocate_plt_objects(const Obj_Entry *); 283 void _rtld_setup_pltgot(const Obj_Entry *); 284 285 /* search.c */ 286 Obj_Entry *_rtld_load_library(const char *, const Obj_Entry *, int); 287 288 /* symbol.c */ 289 unsigned long _rtld_elf_hash(const char *); 290 const Elf_Sym *_rtld_symlook_obj(const char *, unsigned long, 291 const Obj_Entry *, bool); 292 const Elf_Sym *_rtld_find_symdef(unsigned long, const Obj_Entry *, 293 const Obj_Entry **, bool); 294 const Elf_Sym *_rtld_find_plt_symdef(unsigned long, const Obj_Entry *, 295 const Obj_Entry **, bool); 296 297 const Elf_Sym *_rtld_symlook_list(const char *, unsigned long, 298 const Objlist *, const Obj_Entry **, bool, DoneList *); 299 const Elf_Sym *_rtld_symlook_default(const char *, unsigned long, 300 const Obj_Entry *, const Obj_Entry **, bool); 301 const Elf_Sym *_rtld_symlook_needed(const char *, unsigned long, 302 const Needed_Entry *, const Obj_Entry **, bool, 303 DoneList *, DoneList *); 304 #ifdef COMBRELOC 305 void _rtld_combreloc_reset(const Obj_Entry *); 306 #endif 307 308 /* map_object.c */ 309 Obj_Entry *_rtld_map_object(const char *, int, const struct stat *); 310 void _rtld_obj_free(Obj_Entry *); 311 Obj_Entry *_rtld_obj_new(void); 312 313 /* function descriptors */ 314 #ifdef __HAVE_FUNCTION_DESCRIPTORS 315 Elf_Addr _rtld_function_descriptor_alloc(const Obj_Entry *, 316 const Elf_Sym *, Elf_Addr); 317 const void *_rtld_function_descriptor_function(const void *); 318 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 319 320 #endif /* _RTLD_SOURCE */ 321 322 #endif /* RTLD_H */ 323
Indexes created Wed Oct 01 13:09:50 GMT 2025