rtld.h revision 1.79.4.4
1 /* $NetBSD: rtld.h,v 1.79.4.4 2012/03/17 18:28:31 bouyer 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 int _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_Name_Entry { 89 STAILQ_ENTRY(Struct_Name_Entry) link; 90 char name[1]; 91 } Name_Entry; 92 93 typedef struct Struct_Needed_Entry { 94 struct Struct_Needed_Entry *next; 95 struct Struct_Obj_Entry *obj; 96 unsigned long name; /* Offset of name in string table */ 97 } Needed_Entry; 98 99 typedef struct _rtld_search_path_t { 100 struct _rtld_search_path_t *sp_next; 101 const char *sp_path; 102 size_t sp_pathlen; 103 } Search_Path; 104 105 106 #define RTLD_MAX_ENTRY 10 107 #define RTLD_MAX_LIBRARY 4 108 #define RTLD_MAX_CTL 2 109 typedef struct _rtld_library_xform_t { 110 struct _rtld_library_xform_t *next; 111 char *name; 112 const char *ctlname; 113 struct { 114 char *value; 115 char *library[RTLD_MAX_LIBRARY]; 116 } entry[RTLD_MAX_ENTRY]; 117 } Library_Xform; 118 119 /* 120 * Shared object descriptor. 121 * 122 * Items marked with "(%)" are dynamically allocated, and must be freed 123 * when the structure is destroyed. 124 */ 125 126 #define RTLD_MAGIC 0xd550b87a 127 #define RTLD_VERSION 1 128 #define RTLD_MAIN 0x800 129 130 typedef struct Struct_Obj_Entry { 131 Elf32_Word magic; /* Magic number (sanity check) */ 132 Elf32_Word version; /* Version number of struct format */ 133 134 struct Struct_Obj_Entry *next; 135 char *path; /* Pathname of underlying file (%) */ 136 int refcount; 137 int dl_refcount; /* Number of times loaded by dlopen */ 138 139 /* These items are computed by map_object() or by digest_phdr(). */ 140 caddr_t mapbase; /* Base address of mapped region */ 141 size_t mapsize; /* Size of mapped region in bytes */ 142 size_t textsize; /* Size of text segment in bytes */ 143 Elf_Addr vaddrbase; /* Base address in shared object file */ 144 caddr_t relocbase; /* Reloc const = mapbase - *vaddrbase */ 145 Elf_Dyn *dynamic; /* Dynamic section */ 146 caddr_t entry; /* Entry point */ 147 const Elf_Phdr *phdr; /* Program header (may be xmalloc'ed) */ 148 size_t phsize; /* Size of program header in bytes */ 149 150 /* Items from the dynamic section. */ 151 Elf_Addr *pltgot; /* PLTGOT table */ 152 const Elf_Rel *rel; /* Relocation entries */ 153 const Elf_Rel *rellim; /* Limit of Relocation entries */ 154 const Elf_Rela *rela; /* Relocation entries */ 155 const Elf_Rela *relalim; /* Limit of Relocation entries */ 156 const Elf_Rel *pltrel; /* PLT relocation entries */ 157 const Elf_Rel *pltrellim; /* Limit of PLT relocation entries */ 158 const Elf_Rela *pltrela; /* PLT relocation entries */ 159 const Elf_Rela *pltrelalim; /* Limit of PLT relocation entries */ 160 const Elf_Sym *symtab; /* Symbol table */ 161 const char *strtab; /* String table */ 162 unsigned long strsize; /* Size in bytes of string table */ 163 #ifdef __mips__ 164 Elf_Word local_gotno; /* Number of local GOT entries */ 165 Elf_Word symtabno; /* Number of dynamic symbols */ 166 Elf_Word gotsym; /* First dynamic symbol in GOT */ 167 #endif 168 169 const Elf_Word *buckets; /* Hash table buckets array */ 170 unsigned long nbuckets; /* Number of buckets */ 171 const Elf_Word *chains; /* Hash table chain array */ 172 unsigned long nchains; /* Number of chains */ 173 174 Search_Path *rpaths; /* Search path specified in object */ 175 Needed_Entry *needed; /* Shared objects needed by this (%) */ 176 177 void (*init)(void); /* Initialization function to call */ 178 void (*fini)(void); /* Termination function to call */ 179 180 /* Entry points for dlopen() and friends. */ 181 void *(*dlopen)(const char *, int); 182 void *(*dlsym)(void *, const char *); 183 char *(*dlerror)(void); 184 int (*dlclose)(void *); 185 int (*dladdr)(const void *, Dl_info *); 186 187 u_int32_t mainprog:1, /* True if this is the main program */ 188 rtld:1, /* True if this is the dynamic linker */ 189 textrel:1, /* True if there are relocations to 190 * text seg */ 191 symbolic:1, /* True if generated with 192 * "-Bsymbolic" */ 193 printed:1, /* True if ldd has printed it */ 194 isdynamic:1, /* True if this is a pure PIC object */ 195 mainref:1, /* True if on _rtld_list_main */ 196 globalref:1, /* True if on _rtld_list_global */ 197 init_done:1, /* True if .init has been added */ 198 init_called:1, /* True if .init function has been 199 * called */ 200 fini_called:1, /* True if .fini function has been 201 * called */ 202 initfirst:1, /* True if object's .init/.fini take 203 * priority over others */ 204 phdr_loaded:1; /* Phdr is loaded and doesn't need to 205 * be freed. */ 206 207 struct link_map linkmap; /* for GDB */ 208 209 /* These items are computed by map_object() or by digest_phdr(). */ 210 const char *interp; /* Pathname of the interpreter, if any */ 211 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 212 Objlist dagmembers; /* DAG has these members (%) */ 213 dev_t dev; /* Object's filesystem's device */ 214 ino_t ino; /* Object's inode number */ 215 216 void *ehdr; 217 size_t pathlen; /* Pathname length */ 218 STAILQ_HEAD(, Struct_Name_Entry) names; /* List of names for this object we 219 know about. */ 220 } Obj_Entry; 221 222 typedef struct Struct_DoneList { 223 const Obj_Entry **objs; /* Array of object pointers */ 224 unsigned int num_alloc; /* Allocated size of the array */ 225 unsigned int num_used; /* Number of array slots used */ 226 } DoneList; 227 228 229 #if defined(_RTLD_SOURCE) 230 231 extern struct r_debug _rtld_debug; 232 extern Search_Path *_rtld_default_paths; 233 extern Obj_Entry *_rtld_objlist; 234 extern Obj_Entry **_rtld_objtail; 235 extern u_int _rtld_objcount; 236 extern u_int _rtld_objloads; 237 extern Obj_Entry *_rtld_objmain; 238 extern Obj_Entry _rtld_objself; 239 extern Search_Path *_rtld_paths; 240 extern Library_Xform *_rtld_xforms; 241 extern bool _rtld_trust; 242 extern Objlist _rtld_list_global; 243 extern Objlist _rtld_list_main; 244 extern Elf_Sym _rtld_sym_zero; 245 246 /* rtld.c */ 247 248 /* We export these symbols using _rtld_symbol_lookup and is_exported. */ 249 char *dlerror(void); 250 void *dlopen(const char *, int); 251 void *dlsym(void *, const char *); 252 int dlclose(void *); 253 int dladdr(const void *, Dl_info *); 254 int dlinfo(void *, int, void *); 255 int dl_iterate_phdr(int (*)(struct dl_phdr_info *, size_t, void *), 256 void *); 257 258 /* These aren't exported */ 259 void _rtld_error(const char *, ...) 260 __attribute__((__format__(__printf__,1,2))); 261 void _rtld_die(void) __attribute__((__noreturn__)); 262 void *_rtld_objmain_sym(const char *); 263 void _rtld_debug_state(void); 264 void _rtld_linkmap_add(Obj_Entry *); 265 void _rtld_linkmap_delete(Obj_Entry *); 266 void _rtld_objlist_push_head(Objlist *, Obj_Entry *); 267 void _rtld_objlist_push_tail(Objlist *, Obj_Entry *); 268 Objlist_Entry *_rtld_objlist_find(Objlist *, const Obj_Entry *); 269 270 /* expand.c */ 271 size_t _rtld_expand_path(char *, size_t, const char *, const char *,\ 272 const char *); 273 274 /* headers.c */ 275 void _rtld_digest_dynamic(const char *, Obj_Entry *); 276 Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t); 277 278 /* load.c */ 279 Obj_Entry *_rtld_load_object(const char *, int); 280 int _rtld_load_needed_objects(Obj_Entry *, int); 281 int _rtld_preload(const char *); 282 283 /* path.c */ 284 void _rtld_add_paths(const char *, Search_Path **, const char *); 285 void _rtld_process_hints(const char *, Search_Path **, Library_Xform **, 286 const char *); 287 int _rtld_sysctl(const char *, void *, size_t *); 288 289 /* reloc.c */ 290 int _rtld_do_copy_relocations(const Obj_Entry *); 291 int _rtld_relocate_objects(Obj_Entry *, bool); 292 int _rtld_relocate_nonplt_objects(const Obj_Entry *); 293 int _rtld_relocate_plt_lazy(const Obj_Entry *); 294 int _rtld_relocate_plt_objects(const Obj_Entry *); 295 void _rtld_setup_pltgot(const Obj_Entry *); 296 297 /* search.c */ 298 Obj_Entry *_rtld_load_library(const char *, const Obj_Entry *, int); 299 300 /* symbol.c */ 301 unsigned long _rtld_elf_hash(const char *); 302 const Elf_Sym *_rtld_symlook_obj(const char *, unsigned long, 303 const Obj_Entry *, bool); 304 const Elf_Sym *_rtld_find_symdef(unsigned long, const Obj_Entry *, 305 const Obj_Entry **, bool); 306 const Elf_Sym *_rtld_find_plt_symdef(unsigned long, const Obj_Entry *, 307 const Obj_Entry **, bool); 308 309 const Elf_Sym *_rtld_symlook_list(const char *, unsigned long, 310 const Objlist *, const Obj_Entry **, bool, DoneList *); 311 const Elf_Sym *_rtld_symlook_default(const char *, unsigned long, 312 const Obj_Entry *, const Obj_Entry **, bool); 313 const Elf_Sym *_rtld_symlook_needed(const char *, unsigned long, 314 const Needed_Entry *, const Obj_Entry **, bool, 315 DoneList *, DoneList *); 316 #ifdef COMBRELOC 317 void _rtld_combreloc_reset(const Obj_Entry *); 318 #endif 319 320 /* map_object.c */ 321 Obj_Entry *_rtld_map_object(const char *, int, const struct stat *); 322 void _rtld_obj_free(Obj_Entry *); 323 Obj_Entry *_rtld_obj_new(void); 324 325 /* function descriptors */ 326 #ifdef __HAVE_FUNCTION_DESCRIPTORS 327 Elf_Addr _rtld_function_descriptor_alloc(const Obj_Entry *, 328 const Elf_Sym *, Elf_Addr); 329 const void *_rtld_function_descriptor_function(const void *); 330 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 331 332 #endif /* _RTLD_SOURCE */ 333 334 #endif /* RTLD_H */ 335
Indexes created Tue Oct 21 12:09:54 GMT 2025