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 * $DragonFly: src/sys/sys/linker.h,v 1.11 2008/02/06 22:37:46 nth Exp $ 28 */ 29 30 #ifndef _SYS_LINKER_H_ 31 #define _SYS_LINKER_H_ 32 33 #ifndef _SYS_TYPES_H_ 34 #include <sys/types.h> 35 #endif 36 #ifndef _SYS_PARAM_H_ 37 #include <sys/param.h> 38 #endif 39 40 #ifdef _KERNEL 41 42 #ifndef _SYS_QUEUE_H_ 43 #include <sys/queue.h> 44 #endif 45 #ifndef _MACHINE_ELF_H_ 46 #include <machine/elf.h> 47 #endif 48 49 #ifdef MALLOC_DECLARE 50 MALLOC_DECLARE(M_LINKER); 51 #endif 52 53 /* 54 * Object representing a file which has been loaded by the linker. 55 */ 56 typedef struct linker_file* linker_file_t; 57 typedef TAILQ_HEAD(, linker_file) linker_file_list_t; 58 59 typedef caddr_t linker_sym_t; /* opaque symbol */ 60 typedef c_caddr_t c_linker_sym_t; /* const opaque symbol */ 61 62 /* 63 * expanded out linker_sym_t 64 */ 65 typedef struct linker_symval { 66 const char* name; 67 caddr_t value; 68 size_t size; 69 } linker_symval_t; 70 71 struct linker_file_ops { 72 /* 73 * Lookup a symbol in the file's symbol table. If the symbol is 74 * not found then return ENOENT, otherwise zero. If the symbol 75 * found is a common symbol, return with *address set to zero and 76 * *size set to the size of the common space required. Otherwise 77 * set *address the value of the symbol. 78 */ 79 int (*lookup_symbol)(linker_file_t, const char* name, 80 c_linker_sym_t* sym); 81 82 int (*symbol_values)(linker_file_t, c_linker_sym_t, 83 linker_symval_t*); 84 85 int (*search_symbol)(linker_file_t, caddr_t value, 86 c_linker_sym_t* sym, long* diffp); 87 88 /* 89 * Completes the loading task started in preload_file. 90 */ 91 int (*preload_finish)(linker_file_t); 92 93 /* 94 * Unload a file, releasing dependancies and freeing storage. 95 */ 96 void (*unload)(linker_file_t); 97 98 int (*lookup_set)(linker_file_t, const char *name, 99 void ***firstp, void ***lastp, int *countp); 100 }; 101 102 struct common_symbol { 103 STAILQ_ENTRY(common_symbol) link; 104 char* name; 105 caddr_t address; 106 }; 107 108 struct linker_file { 109 int refs; /* reference count */ 110 int userrefs; /* kldload(2) count */ 111 int flags; 112 #define LINKER_FILE_LINKED 0x1 /* file has been fully linked */ 113 TAILQ_ENTRY(linker_file) link; /* list of all loaded files */ 114 char* filename; /* file which was loaded */ 115 int id; /* unique id */ 116 caddr_t address; /* load address */ 117 size_t size; /* size of file */ 118 int ndeps; /* number of dependancies */ 119 linker_file_t* deps; /* list of dependancies */ 120 STAILQ_HEAD(, common_symbol) common; /* list of common symbols */ 121 TAILQ_HEAD(, module) modules; /* modules in this file */ 122 TAILQ_ENTRY(linker_file) loaded; /* preload dependency support */ 123 void* priv; /* implementation data */ 124 125 struct linker_file_ops* ops; 126 }; 127 128 /* 129 * Object implementing a class of file (a.out, elf, etc.) 130 */ 131 typedef struct linker_class *linker_class_t; 132 typedef TAILQ_HEAD(, linker_class) linker_class_list_t; 133 134 struct linker_class_ops { 135 /* 136 * Load a file, returning the new linker_file_t in *result. If 137 * the class does not recognise the file type, zero should be 138 * returned, without modifying *result. If the file is 139 * recognised, the file should be loaded, *result set to the new 140 * file and zero returned. If some other error is detected an 141 * appropriate errno should be returned. 142 */ 143 int (*load_file)(const char *filename, linker_file_t *result); 144 /* 145 * Same as load_file, but does not load dependencies. Necessary 146 * for tentatively loading (loader-)preloaded modules. 147 */ 148 int (*preload_file)(const char *filename, linker_file_t *result); 149 }; 150 151 struct linker_class { 152 TAILQ_ENTRY(linker_class) link; /* list of all file classes */ 153 const char* desc; /* description (e.g. "a.out") */ 154 void* priv; /* implementation data */ 155 156 struct linker_class_ops *ops; 157 }; 158 159 /* 160 * The file which is currently loading. Used to register modules with 161 * the files which contain them. 162 */ 163 extern linker_file_t linker_current_file; 164 165 /* 166 * The "file" for the kernel. 167 */ 168 extern linker_file_t linker_kernel_file; 169 170 /* 171 * Add a new file class to the linker. 172 */ 173 int linker_add_class(const char* _desc, void* _priv, 174 struct linker_class_ops* _ops); 175 176 /* 177 * Load a file, trying each file class until one succeeds. 178 */ 179 int linker_load_file(const char *_filename, linker_file_t *_result); 180 181 /* 182 * Find a currently loaded file given its filename. 183 */ 184 linker_file_t linker_find_file_by_name(const char* _filename); 185 186 /* 187 * Find a currently loaded file given its file id. 188 */ 189 linker_file_t linker_find_file_by_id(int _fileid); 190 191 /* 192 * Called from a class handler when a file is laoded. 193 */ 194 linker_file_t linker_make_file(const char* _filename, void* _priv, 195 struct linker_file_ops* _ops); 196 197 /* 198 * Unload a file, freeing up memory. 199 */ 200 int linker_file_unload(linker_file_t _file); 201 202 /* 203 * Add a dependancy to a file. 204 */ 205 void linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep); 206 207 int linker_load_dependencies(linker_file_t lf); 208 209 /* 210 * Lookup a symbol in a file. If deps is TRUE, look in dependancies 211 * if not found in file. The symbol's value is returned in the 212 * caddr_t. An error is returned, 0 if no error occured. 213 */ 214 int linker_file_lookup_symbol(linker_file_t _file, const char* _name, 215 int _deps, caddr_t *); 216 217 218 /* 219 * Lookup a linker set in a file. Return pointers to the first entry, 220 * last + 1, and count of entries. Use: for (p = start; p < stop; p++) {} 221 * void *start is really: "struct yoursetmember ***start;" 222 */ 223 int linker_file_lookup_set(linker_file_t _file, const char *_name, 224 void *_start, void *_stop, int *_count); 225 226 /* 227 * Search the linker path for the module. Return the full pathname in 228 * a malloc'ed buffer. 229 */ 230 char *linker_search_path(const char *_filename); 231 232 /* 233 * DDB Helpers, tuned specifically for ddb/db_kld.c 234 */ 235 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym); 236 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym, 237 long *_diffp); 238 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval); 239 240 241 #endif /* _KERNEL */ 242 243 /* 244 * Module information subtypes 245 */ 246 #define MODINFO_END 0x0000 /* End of list */ 247 #define MODINFO_NAME 0x0001 /* Name of module (string) */ 248 #define MODINFO_TYPE 0x0002 /* Type of module (string) */ 249 #define MODINFO_ADDR 0x0003 /* Loaded address */ 250 #define MODINFO_SIZE 0x0004 /* Size of module */ 251 #define MODINFO_EMPTY 0x0005 /* Has been deleted */ 252 #define MODINFO_ARGS 0x0006 /* Parameters string */ 253 #define MODINFO_METADATA 0x8000 /* Module-specfic */ 254 255 #define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */ 256 #define MODINFOMD_ELFHDR 0x0002 /* ELF header */ 257 #define MODINFOMD_SSYM 0x0003 /* start of symbols */ 258 #define MODINFOMD_ESYM 0x0004 /* end of symbols */ 259 #define MODINFOMD_DYNAMIC 0x0005 /* _DYNAMIC pointer */ 260 #define MODINFOMD_ENVP 0x0006 /* (from 5.x) envp[] */ 261 #define MODINFOMD_HOWTO 0x0007 /* (from 5.x) boothowto */ 262 #define MODINFOMD_KERNEND 0x0008 /* (from 5.x) kernend */ 263 #define MODINFOMD_SHDR 0x0009 /* section header table */ 264 #define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */ 265 266 #define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */ 267 268 #ifdef _KERNEL 269 #define MD_FETCH(mdp, info, type) ({ \ 270 type *__p; \ 271 __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \ 272 __p ? *__p : 0; \ 273 }) 274 #endif 275 276 #define LINKER_HINTS_VERSION 1 /* linker.hints file version */ 277 278 #ifdef _KERNEL 279 280 /* 281 * Module lookup 282 */ 283 extern caddr_t preload_metadata; 284 extern caddr_t preload_search_by_name(const char *); 285 extern caddr_t preload_search_by_type(const char *); 286 extern caddr_t preload_search_next_name(caddr_t); 287 extern caddr_t preload_search_info(caddr_t, int); 288 extern void preload_delete_name(const char *); 289 extern void preload_bootstrap_relocate(vm_offset_t); 290 extern struct mod_metadata *find_mod_metadata(const char *); 291 292 #ifdef KLD_DEBUG 293 294 extern int kld_debug; 295 #define KLD_DEBUG_FILE 1 /* file load/unload */ 296 #define KLD_DEBUG_SYM 2 /* symbol lookup */ 297 298 #define KLD_DPF(cat, args) \ 299 do { \ 300 if (kld_debug & KLD_DEBUG_##cat) kprintf args; \ 301 } while (0) 302 303 #else 304 305 #define KLD_DPF(cat, args) 306 307 #endif 308 309 typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *); 310 311 /* Support functions */ 312 int elf_reloc(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn); 313 int elf_reloc_local(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn); 314 Elf_Addr elf_relocaddr(linker_file_t, Elf_Addr); 315 316 /* values for type */ 317 #define ELF_RELOC_REL 1 318 #define ELF_RELOC_RELA 2 319 320 #endif /* _KERNEL */ 321 322 struct kld_file_stat { 323 int version; /* set to sizeof(linker_file_stat) */ 324 char name[MAXPATHLEN]; 325 int refs; 326 int id; 327 caddr_t address; /* load address */ 328 size_t size; /* size in bytes */ 329 }; 330 331 struct kld_sym_lookup { 332 int version; /* set to sizeof(struct kld_sym_lookup) */ 333 const char *symname; /* Symbol name we are looking up */ 334 u_long symvalue; 335 size_t symsize; 336 }; 337 338 #define KLDSYM_LOOKUP 1 339 340 #ifndef _KERNEL 341 342 #ifndef _SYS_CDEFS_H_ 343 #include <sys/cdefs.h> 344 #endif 345 346 __BEGIN_DECLS 347 int kldload(const char *); 348 int kldunload(int); 349 int kldfind(const char *); 350 int kldnext(int); 351 int kldstat(int, struct kld_file_stat *); 352 int kldfirstmod(int); 353 int kldsym(int, int, void *); 354 __END_DECLS 355 356 #endif 357 358 #endif /* !_SYS_LINKER_H_ */ 359