1 /*- 2 * Copyright (c) 1997 Doug Rabson 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/sys/sys/linker.h,v 1.17.2.1 2002/03/11 01:13:53 dd Exp $ 27 */ 28 29 #ifndef _SYS_LINKER_H_ 30 #define _SYS_LINKER_H_ 31 32 #ifndef _SYS_TYPES_H_ 33 #include <sys/types.h> 34 #endif 35 #ifndef _SYS_PARAM_H_ 36 #include <sys/param.h> 37 #endif 38 39 #ifdef _KERNEL 40 41 #ifndef _SYS_QUEUE_H_ 42 #include <sys/queue.h> 43 #endif 44 #include <machine/elf.h> 45 46 #include <sys/module.h> 47 48 #ifdef MALLOC_DECLARE 49 MALLOC_DECLARE(M_LINKER); 50 #endif 51 52 /* 53 * Object representing a file which has been loaded by the linker. 54 */ 55 typedef struct linker_file* linker_file_t; 56 typedef TAILQ_HEAD(, linker_file) linker_file_list_t; 57 58 typedef caddr_t linker_sym_t; /* opaque symbol */ 59 typedef c_caddr_t c_linker_sym_t; /* const opaque symbol */ 60 61 /* 62 * expanded out linker_sym_t 63 */ 64 typedef struct linker_symval { 65 const char* name; 66 caddr_t value; 67 size_t size; 68 } linker_symval_t; 69 70 struct linker_file_ops { 71 /* 72 * Lookup a symbol in the file's symbol table. If the symbol is 73 * not found then return ENOENT, otherwise zero. If the symbol 74 * found is a common symbol, return with *address set to zero and 75 * *size set to the size of the common space required. Otherwise 76 * set *address the value of the symbol. 77 */ 78 int (*lookup_symbol)(linker_file_t, const char* name, 79 c_linker_sym_t* sym); 80 81 int (*symbol_values)(linker_file_t, c_linker_sym_t, 82 linker_symval_t*); 83 84 int (*search_symbol)(linker_file_t, caddr_t value, 85 c_linker_sym_t* sym, long* diffp); 86 87 /* 88 * Completes the loading task started in preload_file. 89 */ 90 int (*preload_finish)(linker_file_t); 91 92 /* 93 * Unload a file, releasing dependancies and freeing storage. 94 */ 95 void (*unload)(linker_file_t); 96 97 int (*lookup_set)(linker_file_t, const char *name, 98 void ***firstp, void ***lastp, int *countp); 99 }; 100 101 struct common_symbol { 102 STAILQ_ENTRY(common_symbol) link; 103 char* name; 104 caddr_t address; 105 }; 106 107 struct linker_file { 108 int refs; /* reference count */ 109 int userrefs; /* kldload(2) count */ 110 int flags; 111 #define LINKER_FILE_LINKED 0x1 /* file has been fully linked */ 112 TAILQ_ENTRY(linker_file) link; /* list of all loaded files */ 113 char* filename; /* file which was loaded */ 114 int id; /* unique id */ 115 caddr_t address; /* load address */ 116 size_t size; /* size of file */ 117 int ndeps; /* number of dependancies */ 118 linker_file_t* deps; /* list of dependancies */ 119 STAILQ_HEAD(, common_symbol) common; /* list of common symbols */ 120 TAILQ_HEAD(, module) modules; /* modules in this file */ 121 TAILQ_ENTRY(linker_file) loaded; /* preload dependency support */ 122 void* priv; /* implementation data */ 123 124 struct linker_file_ops* ops; 125 }; 126 127 /* 128 * Object implementing a class of file (a.out, elf, etc.) 129 */ 130 typedef struct linker_class *linker_class_t; 131 typedef TAILQ_HEAD(, linker_class) linker_class_list_t; 132 133 struct linker_class_ops { 134 /* 135 * Load a file, returning the new linker_file_t in *result. If 136 * the class does not recognise the file type, zero should be 137 * returned, without modifying *result. If the file is 138 * recognised, the file should be loaded, *result set to the new 139 * file and zero returned. If some other error is detected an 140 * appropriate errno should be returned. 141 */ 142 int (*load_file)(const char *filename, linker_file_t *result); 143 /* 144 * Same as load_file, but does not load dependencies. Necessary 145 * for tentatively loading (loader-)preloaded modules. 146 */ 147 int (*preload_file)(const char *filename, linker_file_t *result); 148 }; 149 150 struct linker_class { 151 TAILQ_ENTRY(linker_class) link; /* list of all file classes */ 152 const char* desc; /* description (e.g. "a.out") */ 153 void* priv; /* implementation data */ 154 155 struct linker_class_ops *ops; 156 }; 157 158 /* 159 * Function type used when iterating over the list of linker files. 160 */ 161 typedef int linker_predicate_t(linker_file_t, void *); 162 163 /* 164 * The file which is currently loading. Used to register modules with 165 * the files which contain them. 166 */ 167 extern linker_file_t linker_current_file; 168 169 /* 170 * The "file" for the kernel. 171 */ 172 extern linker_file_t linker_kernel_file; 173 174 /* 175 * Add a new file class to the linker. 176 */ 177 int linker_add_class(const char* _desc, void* _priv, 178 struct linker_class_ops* _ops); 179 180 /* 181 * Load a file, trying each file class until one succeeds. 182 */ 183 int linker_load_file(const char *_filename, linker_file_t *_result); 184 185 /* 186 * Find a currently loaded file given its filename. 187 */ 188 linker_file_t linker_find_file_by_name(const char* _filename); 189 190 /* 191 * Find a currently loaded file given its file id. 192 */ 193 linker_file_t linker_find_file_by_id(int _fileid); 194 195 /* 196 * Called from a class handler when a file is laoded. 197 */ 198 linker_file_t linker_make_file(const char* _filename, void* _priv, 199 struct linker_file_ops* _ops); 200 201 /* 202 * Unload a file, freeing up memory. 203 */ 204 int linker_file_unload(linker_file_t _file); 205 206 /* 207 * Add a dependancy to a file. 208 */ 209 void linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep); 210 211 int linker_load_dependencies(linker_file_t lf); 212 213 /* 214 * Iterate over all of the currently loaded linker files calling the 215 * predicate function while the function returns 0. Returns the value 216 * returned by the last predicate function. 217 */ 218 int linker_file_foreach(linker_predicate_t *_predicate, void *_context); 219 220 /* 221 * Lookup a symbol in a file. If deps is TRUE, look in dependancies 222 * if not found in file. The symbol's value is returned in the 223 * caddr_t. An error is returned, 0 if no error occured. 224 */ 225 int linker_file_lookup_symbol(linker_file_t _file, const char* _name, 226 int _deps, caddr_t *); 227 228 229 /* 230 * Lookup a linker set in a file. Return pointers to the first entry, 231 * last + 1, and count of entries. Use: for (p = start; p < stop; p++) {} 232 * void *start is really: "struct yoursetmember ***start;" 233 */ 234 int linker_file_lookup_set(linker_file_t _file, const char *_name, 235 void *_start, void *_stop, int *_count); 236 237 /* 238 * Search the linker path for the module. Return the full pathname in 239 * a malloc'ed buffer. 240 */ 241 char *linker_search_path(const char *_filename); 242 243 int linker_reference_module(const char *modname, struct mod_depend *verinfo, 244 linker_file_t *retult); 245 int linker_release_module(const char *modname, struct mod_depend *verinfo, 246 linker_file_t lf); 247 248 /* 249 * DDB Helpers, tuned specifically for ddb/db_kld.c 250 */ 251 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym); 252 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym, 253 long *_diffp); 254 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval); 255 256 257 #endif /* _KERNEL */ 258 259 /* 260 * Module information subtypes 261 */ 262 #define MODINFO_END 0x0000 /* End of list */ 263 #define MODINFO_NAME 0x0001 /* Name of module (string) */ 264 #define MODINFO_TYPE 0x0002 /* Type of module (string) */ 265 #define MODINFO_ADDR 0x0003 /* Loaded address */ 266 #define MODINFO_SIZE 0x0004 /* Size of module */ 267 #define MODINFO_EMPTY 0x0005 /* Has been deleted */ 268 #define MODINFO_ARGS 0x0006 /* Parameters string */ 269 #define MODINFO_METADATA 0x8000 /* Module-specfic */ 270 271 #define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */ 272 #define MODINFOMD_ELFHDR 0x0002 /* ELF header */ 273 #define MODINFOMD_SSYM 0x0003 /* start of symbols */ 274 #define MODINFOMD_ESYM 0x0004 /* end of symbols */ 275 #define MODINFOMD_DYNAMIC 0x0005 /* _DYNAMIC pointer */ 276 #define MODINFOMD_ENVP 0x0006 /* (from 5.x) envp[] */ 277 #define MODINFOMD_HOWTO 0x0007 /* (from 5.x) boothowto */ 278 #define MODINFOMD_KERNEND 0x0008 /* (from 5.x) kernend */ 279 #define MODINFOMD_SHDR 0x0009 /* section header table */ 280 #define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */ 281 282 #define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */ 283 284 #ifdef _KERNEL 285 #define MD_FETCH(mdp, info, type) ({ \ 286 type *__p; \ 287 __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \ 288 __p ? *__p : 0; \ 289 }) 290 #endif 291 292 #define LINKER_HINTS_VERSION 1 /* linker.hints file version */ 293 294 #ifdef _KERNEL 295 296 /* 297 * Module lookup 298 */ 299 extern caddr_t preload_metadata; 300 extern caddr_t preload_search_by_name(const char *); 301 extern caddr_t preload_search_by_type(const char *); 302 extern caddr_t preload_search_next_name(caddr_t); 303 extern caddr_t preload_search_info(caddr_t, int); 304 extern void preload_delete_name(const char *); 305 extern void preload_bootstrap_relocate(vm_offset_t); 306 extern struct mod_metadata *find_mod_metadata(const char *); 307 308 #ifdef KLD_DEBUG 309 310 extern int kld_debug; 311 #define KLD_DEBUG_FILE 1 /* file load/unload */ 312 #define KLD_DEBUG_SYM 2 /* symbol lookup */ 313 314 #define KLD_DPF(cat, args) \ 315 do { \ 316 if (kld_debug & KLD_DEBUG_##cat) kprintf args; \ 317 } while (0) 318 319 #else 320 321 #define KLD_DPF(cat, args) 322 323 #endif 324 325 typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *); 326 327 /* Support functions */ 328 int elf_reloc(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn); 329 int elf_reloc_local(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn); 330 Elf_Addr elf_relocaddr(linker_file_t, Elf_Addr); 331 332 /* values for type */ 333 #define ELF_RELOC_REL 1 334 #define ELF_RELOC_RELA 2 335 336 #endif /* _KERNEL */ 337 338 struct kld_file_stat { 339 int version; /* set to sizeof(linker_file_stat) */ 340 char name[MAXPATHLEN]; 341 int refs; 342 int id; 343 caddr_t address; /* load address */ 344 size_t size; /* size in bytes */ 345 }; 346 347 struct kld_sym_lookup { 348 int version; /* set to sizeof(struct kld_sym_lookup) */ 349 const char *symname; /* Symbol name we are looking up */ 350 u_long symvalue; 351 size_t symsize; 352 }; 353 354 #define KLDSYM_LOOKUP 1 355 356 #ifndef _KERNEL 357 358 #ifndef _SYS_CDEFS_H_ 359 #include <sys/cdefs.h> 360 #endif 361 362 __BEGIN_DECLS 363 int kldload(const char *); 364 int kldunload(int); 365 int kldfind(const char *); 366 int kldnext(int); 367 int kldstat(int, struct kld_file_stat *); 368 int kldfirstmod(int); 369 int kldsym(int, int, void *); 370 __END_DECLS 371 372 #endif 373 374 #endif /* !_SYS_LINKER_H_ */ 375