2 * Copyright (c) 1997 Doug Rabson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
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 $
30 #ifndef _SYS_LINKER_H_
31 #define _SYS_LINKER_H_
34 #include <sys/types.h>
37 #include <sys/param.h>
43 #include <sys/queue.h>
45 #ifndef _MACHINE_ELF_H_
46 #include <machine/elf.h>
50 MALLOC_DECLARE(M_LINKER);
54 * Object representing a file which has been loaded by the linker.
56 typedef struct linker_file* linker_file_t;
57 typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
59 typedef caddr_t linker_sym_t; /* opaque symbol */
60 typedef c_caddr_t c_linker_sym_t; /* const opaque symbol */
63 * expanded out linker_sym_t
65 typedef struct linker_symval {
71 struct linker_file_ops {
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.
79 int (*lookup_symbol)(linker_file_t, const char* name,
82 int (*symbol_values)(linker_file_t, c_linker_sym_t,
85 int (*search_symbol)(linker_file_t, caddr_t value,
86 c_linker_sym_t* sym, long* diffp);
89 * Completes the loading task started in preload_file.
91 int (*preload_finish)(linker_file_t);
94 * Unload a file, releasing dependancies and freeing storage.
96 void (*unload)(linker_file_t);
98 int (*lookup_set)(linker_file_t, const char *name,
99 void ***firstp, void ***lastp, int *countp);
102 struct common_symbol {
103 STAILQ_ENTRY(common_symbol) link;
109 int refs; /* reference count */
110 int userrefs; /* kldload(2) count */
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 */
125 struct linker_file_ops* ops;
129 * Object implementing a class of file (a.out, elf, etc.)
131 typedef struct linker_class *linker_class_t;
132 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
134 struct linker_class_ops {
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.
143 int (*load_file)(const char *filename, linker_file_t *result);
145 * Same as load_file, but does not load dependencies. Necessary
146 * for tentatively loading (loader-)preloaded modules.
148 int (*preload_file)(const char *filename, linker_file_t *result);
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 */
156 struct linker_class_ops *ops;
160 * The file which is currently loading. Used to register modules with
161 * the files which contain them.
163 extern linker_file_t linker_current_file;
166 * The "file" for the kernel.
168 extern linker_file_t linker_kernel_file;
171 * Add a new file class to the linker.
173 int linker_add_class(const char* _desc, void* _priv,
174 struct linker_class_ops* _ops);
177 * Load a file, trying each file class until one succeeds.
179 int linker_load_file(const char *_filename, linker_file_t *_result);
182 * Find a currently loaded file given its filename.
184 linker_file_t linker_find_file_by_name(const char* _filename);
187 * Find a currently loaded file given its file id.
189 linker_file_t linker_find_file_by_id(int _fileid);
192 * Called from a class handler when a file is laoded.
194 linker_file_t linker_make_file(const char* _filename, void* _priv,
195 struct linker_file_ops* _ops);
198 * Unload a file, freeing up memory.
200 int linker_file_unload(linker_file_t _file);
203 * Add a dependancy to a file.
205 void linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep);
207 int linker_load_dependencies(linker_file_t lf);
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.
214 int linker_file_lookup_symbol(linker_file_t _file, const char* _name,
215 int _deps, caddr_t *);
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;"
223 int linker_file_lookup_set(linker_file_t _file, const char *_name,
224 void *_start, void *_stop, int *_count);
227 * Search the linker path for the module. Return the full pathname in
228 * a malloc'ed buffer.
230 char *linker_search_path(const char *_filename);
233 * DDB Helpers, tuned specifically for ddb/db_kld.c
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,
238 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
244 * Module information subtypes
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 */
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 */
266 #define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */
269 #define MD_FETCH(mdp, info, type) ({ \
271 __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
276 #define LINKER_HINTS_VERSION 1 /* linker.hints file version */
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 *);
294 extern int kld_debug;
295 #define KLD_DEBUG_FILE 1 /* file load/unload */
296 #define KLD_DEBUG_SYM 2 /* symbol lookup */
298 #define KLD_DPF(cat, args) \
300 if (kld_debug & KLD_DEBUG_##cat) kprintf args; \
305 #define KLD_DPF(cat, args)
309 typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *);
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);
316 /* values for type */
317 #define ELF_RELOC_REL 1
318 #define ELF_RELOC_RELA 2
322 struct kld_file_stat {
323 int version; /* set to sizeof(linker_file_stat) */
324 char name[MAXPATHLEN];
327 caddr_t address; /* load address */
328 size_t size; /* size in bytes */
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 */
338 #define KLDSYM_LOOKUP 1
342 #ifndef _SYS_CDEFS_H_
343 #include <sys/cdefs.h>
347 int kldload(const char *);
349 int kldfind(const char *);
351 int kldstat(int, struct kld_file_stat *);
352 int kldfirstmod(int);
353 int kldsym(int, int, void *);
358 #endif /* !_SYS_LINKER_H_ */