rtld.h revision 1.76
1 /* $NetBSD: rtld.h,v 1.76 2007/12/07 20:34:05 ad 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 #endif /* _RTLD_SOURCE */ 63 64 /* 65 * C++ has mandated the use of the following keywords for its new boolean 66 * type. We might as well follow their lead. 67 */ 68 struct Struct_Obj_Entry; 69 70 typedef struct Struct_Objlist_Entry { 71 SIMPLEQ_ENTRY(Struct_Objlist_Entry) link; 72 struct Struct_Obj_Entry *obj; 73 } Objlist_Entry; 74 75 typedef SIMPLEQ_HEAD(Struct_Objlist, Struct_Objlist_Entry) Objlist; 76 77 typedef struct Struct_Needed_Entry { 78 struct Struct_Needed_Entry *next; 79 struct Struct_Obj_Entry *obj; 80 unsigned long name; /* Offset of name in string table */ 81 } Needed_Entry; 82 83 typedef struct _rtld_search_path_t { 84 struct _rtld_search_path_t *sp_next; 85 const char *sp_path; 86 size_t sp_pathlen; 87 } Search_Path; 88 89 90 #define RTLD_MAX_ENTRY 10 91 #define RTLD_MAX_LIBRARY 4 92 #define RTLD_MAX_CTL 2 93 typedef struct _rtld_library_xform_t { 94 struct _rtld_library_xform_t *next; 95 char *name; 96 const char *ctlname; 97 struct { 98 char *value; 99 char *library[RTLD_MAX_LIBRARY]; 100 } entry[RTLD_MAX_ENTRY]; 101 } Library_Xform; 102 103 /* 104 * Shared object descriptor. 105 * 106 * Items marked with "(%)" are dynamically allocated, and must be freed 107 * when the structure is destroyed. 108 */ 109 110 #define RTLD_MAGIC 0xd550b87a 111 #define RTLD_VERSION 1 112 #define RTLD_MAIN 0x800 113 114 typedef struct Struct_Obj_Entry { 115 Elf32_Word magic; /* Magic number (sanity check) */ 116 Elf32_Word version; /* Version number of struct format */ 117 118 struct Struct_Obj_Entry *next; 119 char *path; /* Pathname of underlying file (%) */ 120 int refcount; 121 int dl_refcount; /* Number of times loaded by dlopen */ 122 123 /* These items are computed by map_object() or by digest_phdr(). */ 124 caddr_t mapbase; /* Base address of mapped region */ 125 size_t mapsize; /* Size of mapped region in bytes */ 126 size_t textsize; /* Size of text segment in bytes */ 127 Elf_Addr vaddrbase; /* Base address in shared object file */ 128 caddr_t relocbase; /* Reloc const = mapbase - *vaddrbase */ 129 Elf_Dyn *dynamic; /* Dynamic section */ 130 caddr_t entry; /* Entry point */ 131 const Elf_Phdr *__junk001; 132 size_t pathlen; /* Pathname length */ 133 134 /* Items from the dynamic section. */ 135 Elf_Addr *pltgot; /* PLTGOT table */ 136 const Elf_Rel *rel; /* Relocation entries */ 137 const Elf_Rel *rellim; /* Limit of Relocation entries */ 138 const Elf_Rela *rela; /* Relocation entries */ 139 const Elf_Rela *relalim; /* Limit of Relocation entries */ 140 const Elf_Rel *pltrel; /* PLT relocation entries */ 141 const Elf_Rel *pltrellim; /* Limit of PLT relocation entries */ 142 const Elf_Rela *pltrela; /* PLT relocation entries */ 143 const Elf_Rela *pltrelalim; /* Limit of PLT relocation entries */ 144 const Elf_Sym *symtab; /* Symbol table */ 145 const char *strtab; /* String table */ 146 unsigned long strsize; /* Size in bytes of string table */ 147 #ifdef __mips__ 148 Elf_Word local_gotno; /* Number of local GOT entries */ 149 Elf_Word symtabno; /* Number of dynamic symbols */ 150 Elf_Word gotsym; /* First dynamic symbol in GOT */ 151 #endif 152 153 const Elf_Word *buckets; /* Hash table buckets array */ 154 unsigned long nbuckets; /* Number of buckets */ 155 const Elf_Word *chains; /* Hash table chain array */ 156 unsigned long nchains; /* Number of chains */ 157 158 Search_Path *rpaths; /* Search path specified in object */ 159 Needed_Entry *needed; /* Shared objects needed by this (%) */ 160 161 void (*init)(void); /* Initialization function to call */ 162 void (*fini)(void); /* Termination function to call */ 163 164 /* Entry points for dlopen() and friends. */ 165 void *(*dlopen)(const char *, int); 166 void *(*dlsym)(void *, const char *); 167 char *(*dlerror)(void); 168 int (*dlclose)(void *); 169 int (*dladdr)(const void *, Dl_info *); 170 171 u_int32_t mainprog:1, /* True if this is the main program */ 172 rtld:1, /* True if this is the dynamic linker */ 173 textrel:1, /* True if there are relocations to 174 * text seg */ 175 symbolic:1, /* True if generated with 176 * "-Bsymbolic" */ 177 printed:1, /* True if ldd has printed it */ 178 isdynamic:1, /* True if this is a pure PIC object */ 179 mainref:1, /* True if on _rtld_list_main */ 180 globalref:1, /* True if on _rtld_list_global */ 181 init_done:1, /* True if .init has been added */ 182 init_called:1, /* True if .init function has been 183 * called */ 184 fini_called:1, /* True if .fini function has been 185 * called */ 186 initfirst:1; /* True if object's .init/.fini take 187 * priority over others */ 188 189 struct link_map linkmap; /* for GDB */ 190 191 /* These items are computed by map_object() or by digest_phdr(). */ 192 const char *interp; /* Pathname of the interpreter, if any */ 193 Objlist dldags; /* Object belongs to these dlopened DAGs (%) */ 194 Objlist dagmembers; /* DAG has these members (%) */ 195 dev_t dev; /* Object's filesystem's device */ 196 ino_t ino; /* Object's inode number */ 197 } Obj_Entry; 198 199 #if defined(_RTLD_SOURCE) 200 201 extern struct r_debug _rtld_debug; 202 extern Search_Path *_rtld_default_paths; 203 extern Obj_Entry *_rtld_objlist; 204 extern Obj_Entry **_rtld_objtail; 205 extern Obj_Entry *_rtld_objmain; 206 extern Obj_Entry _rtld_objself; 207 extern Search_Path *_rtld_paths; 208 extern Library_Xform *_rtld_xforms; 209 extern bool _rtld_trust; 210 extern Objlist _rtld_list_global; 211 extern Objlist _rtld_list_main; 212 extern Elf_Sym _rtld_sym_zero; 213 214 /* rtld.c */ 215 216 /* 217 * We export these symbols using _rtld_symbol_lookup and is_exported. 218 */ 219 char *dlerror(void); 220 void *dlopen(const char *, int); 221 void *dlsym(void *, const char *); 222 int dlclose(void *); 223 int dladdr(const void *, Dl_info *); 224 225 void _rtld_error(const char *, ...) 226 __attribute__((__format__(__printf__,1,2))); 227 void _rtld_die(void) __attribute__((__noreturn__)); 228 void *_rtld_objmain_sym(const char *); 229 void _rtld_debug_state(void); 230 void _rtld_linkmap_add(Obj_Entry *); 231 void _rtld_linkmap_delete(Obj_Entry *); 232 void _rtld_objlist_push_head(Objlist *, Obj_Entry *); 233 void _rtld_objlist_push_tail(Objlist *, Obj_Entry *); 234 Objlist_Entry *_rtld_objlist_find(Objlist *, const Obj_Entry *); 235 236 /* expand.c */ 237 size_t _rtld_expand_path(char *, size_t, const char *, const char *,\ 238 const char *); 239 240 /* headers.c */ 241 void _rtld_digest_dynamic(const char *, Obj_Entry *); 242 Obj_Entry *_rtld_digest_phdr(const Elf_Phdr *, int, caddr_t); 243 244 /* load.c */ 245 Obj_Entry *_rtld_load_object(const char *, int); 246 int _rtld_load_needed_objects(Obj_Entry *, int); 247 int _rtld_preload(const char *); 248 249 /* path.c */ 250 void _rtld_add_paths(const char *, Search_Path **, const char *); 251 void _rtld_process_hints(const char *, Search_Path **, Library_Xform **, 252 const char *); 253 int _rtld_sysctl(const char *, void *, size_t *); 254 255 /* reloc.c */ 256 int _rtld_do_copy_relocations(const Obj_Entry *); 257 int _rtld_relocate_objects(Obj_Entry *, bool); 258 int _rtld_relocate_nonplt_objects(const Obj_Entry *); 259 int _rtld_relocate_plt_lazy(const Obj_Entry *); 260 int _rtld_relocate_plt_objects(const Obj_Entry *); 261 void _rtld_setup_pltgot(const Obj_Entry *); 262 263 /* search.c */ 264 Obj_Entry *_rtld_load_library(const char *, const Obj_Entry *, int); 265 266 /* symbol.c */ 267 unsigned long _rtld_elf_hash(const char *); 268 const Elf_Sym *_rtld_symlook_obj(const char *, unsigned long, 269 const Obj_Entry *, bool); 270 const Elf_Sym *_rtld_find_symdef(unsigned long, const Obj_Entry *, 271 const Obj_Entry **, bool); 272 const Elf_Sym *_rtld_symlook_list(const char *, unsigned long, 273 const Objlist *, const Obj_Entry **, bool); 274 const Elf_Sym *_rtld_symlook_default(const char *, unsigned long, 275 const Obj_Entry *, const Obj_Entry **, bool); 276 277 /* map_object.c */ 278 Obj_Entry *_rtld_map_object(const char *, int, const struct stat *); 279 void _rtld_obj_free(Obj_Entry *); 280 Obj_Entry *_rtld_obj_new(void); 281 282 /* function descriptors */ 283 #ifdef __HAVE_FUNCTION_DESCRIPTORS 284 Elf_Addr _rtld_function_descriptor_alloc(const Obj_Entry *, 285 const Elf_Sym *, Elf_Addr); 286 const void *_rtld_function_descriptor_function(const void *); 287 #endif /* __HAVE_FUNCTION_DESCRIPTORS */ 288 289 #endif /* _RTLD_SOURCE */ 290 291 #endif /* RTLD_H */ 292
Indexes created Tue Sep 30 20:09:53 GMT 2025