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 * The file which is currently loading. Used to register modules with 160 * the files which contain them. 161 */ 162 extern linker_file_t linker_current_file; 163 164 /* 165 * The "file" for the kernel. 166 */ 167 extern linker_file_t linker_kernel_file; 168 169 /* 170 * Add a new file class to the linker. 171 */ 172 int linker_add_class(const char* _desc, void* _priv, 173 struct linker_class_ops* _ops); 174 175 /* 176 * Load a file, trying each file class until one succeeds. 177 */ 178 int linker_load_file(const char *_filename, linker_file_t *_result); 179 180 /* 181 * Find a currently loaded file given its filename. 182 */ 183 linker_file_t linker_find_file_by_name(const char* _filename); 184 185 /* 186 * Find a currently loaded file given its file id. 187 */ 188 linker_file_t linker_find_file_by_id(int _fileid); 189 190 /* 191 * Called from a class handler when a file is laoded. 192 */ 193 linker_file_t linker_make_file(const char* _filename, void* _priv, 194 struct linker_file_ops* _ops); 195 196 /* 197 * Unload a file, freeing up memory. 198 */ 199 int linker_file_unload(linker_file_t _file); 200 201 /* 202 * Add a dependancy to a file. 203 */ 204 void linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep); 205 206 int linker_load_dependencies(linker_file_t lf); 207 208 /* 209 * Lookup a symbol in a file. If deps is TRUE, look in dependancies 210 * if not found in file. The symbol's value is returned in the 211 * caddr_t. An error is returned, 0 if no error occured. 212 */ 213 int linker_file_lookup_symbol(linker_file_t _file, const char* _name, 214 int _deps, caddr_t *); 215 216 217 /* 218 * Lookup a linker set in a file. Return pointers to the first entry, 219 * last + 1, and count of entries. Use: for (p = start; p < stop; p++) {} 220 * void *start is really: "struct yoursetmember ***start;" 221 */ 222 int linker_file_lookup_set(linker_file_t _file, const char *_name, 223 void *_start, void *_stop, int *_count); 224 225 /* 226 * Search the linker path for the module. Return the full pathname in 227 * a malloc'ed buffer. 228 */ 229 char *linker_search_path(const char *_filename); 230 231 int linker_reference_module(const char *modname, struct mod_depend *verinfo, 232 linker_file_t *retult); 233 int linker_release_module(const char *modname, struct mod_depend *verinfo, 234 linker_file_t lf); 235 236 /* 237 * DDB Helpers, tuned specifically for ddb/db_kld.c 238 */ 239 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym); 240 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym, 241 long *_diffp); 242 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval); 243 244 245 #endif /* _KERNEL */ 246 247 /* 248 * Module information subtypes 249 */ 250 #define MODINFO_END 0x0000 /* End of list */ 251 #define MODINFO_NAME 0x0001 /* Name of module (string) */ 252 #define MODINFO_TYPE 0x0002 /* Type of module (string) */ 253 #define MODINFO_ADDR 0x0003 /* Loaded address */ 254 #define MODINFO_SIZE 0x0004 /* Size of module */ 255 #define MODINFO_EMPTY 0x0005 /* Has been deleted */ 256 #define MODINFO_ARGS 0x0006 /* Parameters string */ 257 #define MODINFO_METADATA 0x8000 /* Module-specfic */ 258 259 #define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */ 260 #define MODINFOMD_ELFHDR 0x0002 /* ELF header */ 261 #define MODINFOMD_SSYM 0x0003 /* start of symbols */ 262 #define MODINFOMD_ESYM 0x0004 /* end of symbols */ 263 #define MODINFOMD_DYNAMIC 0x0005 /* _DYNAMIC pointer */ 264 #define MODINFOMD_ENVP 0x0006 /* (from 5.x) envp[] */ 265 #define MODINFOMD_HOWTO 0x0007 /* (from 5.x) boothowto */ 266 #define MODINFOMD_KERNEND 0x0008 /* (from 5.x) kernend */ 267 #define MODINFOMD_SHDR 0x0009 /* section header table */ 268 #define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */ 269 270 #define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */ 271 272 #ifdef _KERNEL 273 #define MD_FETCH(mdp, info, type) ({ \ 274 type *__p; \ 275 __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \ 276 __p ? *__p : 0; \ 277 }) 278 #endif 279 280 #define LINKER_HINTS_VERSION 1 /* linker.hints file version */ 281 282 #ifdef _KERNEL 283 284 /* 285 * Module lookup 286 */ 287 extern caddr_t preload_metadata; 288 extern caddr_t preload_search_by_name(const char *); 289 extern caddr_t preload_search_by_type(const char *); 290 extern caddr_t preload_search_next_name(caddr_t); 291 extern caddr_t preload_search_info(caddr_t, int); 292 extern void preload_delete_name(const char *); 293 extern void preload_bootstrap_relocate(vm_offset_t); 294 extern struct mod_metadata *find_mod_metadata(const char *); 295 296 #ifdef KLD_DEBUG 297 298 extern int kld_debug; 299 #define KLD_DEBUG_FILE 1 /* file load/unload */ 300 #define KLD_DEBUG_SYM 2 /* symbol lookup */ 301 302 #define KLD_DPF(cat, args) \ 303 do { \ 304 if (kld_debug & KLD_DEBUG_##cat) kprintf args; \ 305 } while (0) 306 307 #else 308 309 #define KLD_DPF(cat, args) 310 311 #endif 312 313 typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *); 314 315 /* Support functions */ 316 int elf_reloc(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn); 317 int elf_reloc_local(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn); 318 Elf_Addr elf_relocaddr(linker_file_t, Elf_Addr); 319 320 /* values for type */ 321 #define ELF_RELOC_REL 1 322 #define ELF_RELOC_RELA 2 323 324 #endif /* _KERNEL */ 325 326 struct kld_file_stat { 327 int version; /* set to sizeof(linker_file_stat) */ 328 char name[MAXPATHLEN]; 329 int refs; 330 int id; 331 caddr_t address; /* load address */ 332 size_t size; /* size in bytes */ 333 }; 334 335 struct kld_sym_lookup { 336 int version; /* set to sizeof(struct kld_sym_lookup) */ 337 const char *symname; /* Symbol name we are looking up */ 338 u_long symvalue; 339 size_t symsize; 340 }; 341 342 #define KLDSYM_LOOKUP 1 343 344 #ifndef _KERNEL 345 346 #ifndef _SYS_CDEFS_H_ 347 #include <sys/cdefs.h> 348 #endif 349 350 __BEGIN_DECLS 351 int kldload(const char *); 352 int kldunload(int); 353 int kldfind(const char *); 354 int kldnext(int); 355 int kldstat(int, struct kld_file_stat *); 356 int kldfirstmod(int); 357 int kldsym(int, int, void *); 358 __END_DECLS 359 360 #endif 361 362 #endif /* !_SYS_LINKER_H_ */ 363