linker.h revision 40906
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 * $Id: linker.h,v 1.9 1998/10/16 03:55:01 peter Exp $ 27 */ 28 29#ifndef _SYS_LINKER_H_ 30#define _SYS_LINKER_H_ 31 32#ifdef KERNEL 33 34#include <machine/elf.h> 35 36#ifdef MALLOC_DECLARE 37MALLOC_DECLARE(M_LINKER); 38#endif 39 40/* 41 * Object representing a file which has been loaded by the linker. 42 */ 43typedef struct linker_file* linker_file_t; 44typedef TAILQ_HEAD(, linker_file) linker_file_list_t; 45 46typedef caddr_t linker_sym_t; /* opaque symbol */ 47 48/* 49 * expanded out linker_sym_t 50 */ 51typedef struct linker_symval { 52 const char* name; 53 caddr_t value; 54 size_t size; 55} linker_symval_t; 56 57struct linker_file_ops { 58 /* 59 * Lookup a symbol in the file's symbol table. If the symbol is 60 * not found then return ENOENT, otherwise zero. If the symbol 61 * found is a common symbol, return with *address set to zero and 62 * *size set to the size of the common space required. Otherwise 63 * set *address the value of the symbol. 64 */ 65 int (*lookup_symbol)(linker_file_t, const char* name, 66 linker_sym_t* sym); 67 68 int (*symbol_values)(linker_file_t, linker_sym_t, 69 linker_symval_t*); 70 71 int (*search_symbol)(linker_file_t, caddr_t value, 72 linker_sym_t* sym, long* diffp); 73 74 /* 75 * Unload a file, releasing dependancies and freeing storage. 76 */ 77 void (*unload)(linker_file_t); 78}; 79 80struct common_symbol { 81 STAILQ_ENTRY(common_symbol) link; 82 char* name; 83 caddr_t address; 84}; 85 86struct linker_file { 87 int refs; /* reference count */ 88 int userrefs; /* kldload(2) count */ 89 TAILQ_ENTRY(linker_file) link; /* list of all loaded files */ 90 char* filename; /* file which was loaded */ 91 int id; /* unique id */ 92 caddr_t address; /* load address */ 93 size_t size; /* size of file */ 94 int ndeps; /* number of dependancies */ 95 linker_file_t* deps; /* list of dependancies */ 96 STAILQ_HEAD(, common_symbol) common; /* list of common symbols */ 97 TAILQ_HEAD(, module) modules; /* modules in this file */ 98 void* priv; /* implementation data */ 99 100 struct linker_file_ops* ops; 101}; 102 103/* 104 * Object implementing a class of file (a.out, elf, etc.) 105 */ 106typedef struct linker_class *linker_class_t; 107typedef TAILQ_HEAD(, linker_class) linker_class_list_t; 108 109struct linker_class_ops { 110 /* 111 * Load a file, returning the new linker_file_t in *result. If 112 * the class does not recognise the file type, zero should be 113 * returned, without modifying *result. If the file is 114 * recognised, the file should be loaded, *result set to the new 115 * file and zero returned. If some other error is detected an 116 * appropriate errno should be returned. 117 */ 118 int (*load_file)(const char* filename, linker_file_t* result); 119}; 120 121struct linker_class { 122 TAILQ_ENTRY(linker_class) link; /* list of all file classes */ 123 const char* desc; /* description (e.g. "a.out") */ 124 void* priv; /* implementation data */ 125 126 struct linker_class_ops *ops; 127}; 128 129/* 130 * The file which is currently loading. Used to register modules with 131 * the files which contain them. 132 */ 133extern linker_file_t linker_current_file; 134 135/* 136 * The "file" for the kernel. 137 */ 138extern linker_file_t linker_kernel_file; 139 140/* 141 * Add a new file class to the linker. 142 */ 143int linker_add_class(const char* desc, void* priv, 144 struct linker_class_ops* ops); 145 146/* 147 * Load a file, trying each file class until one succeeds. 148 */ 149int linker_load_file(const char* filename, linker_file_t* result); 150 151/* 152 * Find a currently loaded file given its filename. 153 */ 154linker_file_t linker_find_file_by_name(const char* filename); 155 156/* 157 * Find a currently loaded file given its file id. 158 */ 159linker_file_t linker_find_file_by_id(int fileid); 160 161/* 162 * Called from a class handler when a file is laoded. 163 */ 164linker_file_t linker_make_file(const char* filename, void* priv, 165 struct linker_file_ops* ops); 166 167/* 168 * Unload a file, freeing up memory. 169 */ 170int linker_file_unload(linker_file_t file); 171 172/* 173 * Add a dependancy to a file. 174 */ 175int linker_file_add_dependancy(linker_file_t file, linker_file_t dep); 176 177/* 178 * Lookup a symbol in a file. If deps is TRUE, look in dependancies 179 * if not found in file. 180 */ 181caddr_t linker_file_lookup_symbol(linker_file_t file, const char* name, 182 int deps); 183 184/* 185 * Search the linker path for the module. Return the full pathname in 186 * a malloc'ed buffer. 187 */ 188char *linker_search_path(const char *filename); 189 190/* 191 * DDB Helpers, tuned specifically for ddb/db_kld.c 192 */ 193int linker_ddb_lookup(char *symstr, linker_sym_t *sym); 194int linker_ddb_search_symbol(caddr_t value, linker_sym_t *sym, long *diffp); 195int linker_ddb_symbol_values(linker_sym_t sym, linker_symval_t *symval); 196 197 198#endif /* KERNEL */ 199 200/* 201 * Module information subtypes 202 */ 203#define MODINFO_END 0x0000 /* End of list */ 204#define MODINFO_NAME 0x0001 /* Name of module (string) */ 205#define MODINFO_TYPE 0x0002 /* Type of module (string) */ 206#define MODINFO_ADDR 0x0003 /* Loaded address */ 207#define MODINFO_SIZE 0x0004 /* Size of module */ 208#define MODINFO_EMPTY 0x0005 /* Has been deleted */ 209#define MODINFO_METADATA 0x8000 /* Module-specfic */ 210 211#define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */ 212#define MODINFOMD_ELFHDR 0x0002 /* ELF header */ 213#define MODINFOMD_SSYM 0x0003 /* start of symbols */ 214#define MODINFOMD_ESYM 0x0004 /* end of symbols */ 215#define MODINFOMD_DYNAMIC 0x0005 /* _DYNAMIC pointer */ 216#define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */ 217 218#define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */ 219 220#ifdef KERNEL 221 222/* 223 * Module lookup 224 */ 225extern caddr_t preload_metadata; 226extern caddr_t preload_search_by_name(const char *name); 227extern caddr_t preload_search_by_type(const char *type); 228extern caddr_t preload_search_next_name(caddr_t base); 229extern caddr_t preload_search_info(caddr_t mod, int inf); 230extern void preload_delete_name(const char *name); 231extern void preload_bootstrap_relocate(vm_offset_t offset); 232 233#ifdef KLD_DEBUG 234 235extern int kld_debug; 236#define KLD_DEBUG_FILE 1 /* file load/unload */ 237#define KLD_DEBUG_SYM 2 /* symbol lookup */ 238 239#define KLD_DPF(cat, args) \ 240 do { \ 241 if (kld_debug & KLD_DEBUG_##cat) printf args; \ 242 } while (0) 243 244#else 245 246#define KLD_DPF(cat, args) 247 248#endif 249 250/* Support functions */ 251int elf_reloc(linker_file_t lf, const void *rel, int type, const char *sym); 252/* values for type */ 253#define ELF_RELOC_REL 1 254#define ELF_RELOC_RELA 2 255 256#endif /* KERNEL */ 257 258struct kld_file_stat { 259 int version; /* set to sizeof(linker_file_stat) */ 260 char name[MAXPATHLEN]; 261 int refs; 262 int id; 263 caddr_t address; /* load address */ 264 size_t size; /* size in bytes */ 265}; 266 267#ifndef KERNEL 268 269#include <sys/cdefs.h> 270 271__BEGIN_DECLS 272int kldload(const char* file); 273int kldunload(int fileid); 274int kldfind(const char* file); 275int kldnext(int fileid); 276int kldstat(int fileid, struct kld_file_stat* stat); 277int kldfirstmod(int fileid); 278__END_DECLS 279 280#endif 281 282#endif /* !_SYS_LINKER_H_ */ 283