FreeBSD/Linux Kernel Cross Reference
sys/sys/linker.h
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 * $FreeBSD$
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
37 MALLOC_DECLARE(M_LINKER);
38 #endif
39
40 /*
41 * Object representing a file which has been loaded by the linker.
42 */
43 typedef struct linker_file* linker_file_t;
44 typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
45
46 typedef caddr_t linker_sym_t; /* opaque symbol */
47 typedef c_caddr_t c_linker_sym_t; /* const opaque symbol */
48
49 /*
50 * expanded out linker_sym_t
51 */
52 typedef struct linker_symval {
53 const char* name;
54 caddr_t value;
55 size_t size;
56 } linker_symval_t;
57
58 struct linker_file_ops {
59 /*
60 * Lookup a symbol in the file's symbol table. If the symbol is
61 * not found then return ENOENT, otherwise zero. If the symbol
62 * found is a common symbol, return with *address set to zero and
63 * *size set to the size of the common space required. Otherwise
64 * set *address the value of the symbol.
65 */
66 int (*lookup_symbol)(linker_file_t, const char* name,
67 c_linker_sym_t* sym);
68
69 int (*symbol_values)(linker_file_t, c_linker_sym_t,
70 linker_symval_t*);
71
72 int (*search_symbol)(linker_file_t, caddr_t value,
73 c_linker_sym_t* sym, long* diffp);
74
75 /*
76 * Unload a file, releasing dependancies and freeing storage.
77 */
78 void (*unload)(linker_file_t);
79 };
80
81 struct common_symbol {
82 STAILQ_ENTRY(common_symbol) link;
83 char* name;
84 caddr_t address;
85 };
86
87 struct linker_file {
88 int refs; /* reference count */
89 int userrefs; /* kldload(2) count */
90 int flags;
91 #define LINKER_FILE_LINKED 0x1 /* file has been fully linked */
92 TAILQ_ENTRY(linker_file) link; /* list of all loaded files */
93 char* filename; /* file which was loaded */
94 int id; /* unique id */
95 caddr_t address; /* load address */
96 size_t size; /* size of file */
97 int ndeps; /* number of dependancies */
98 linker_file_t* deps; /* list of dependancies */
99 STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
100 TAILQ_HEAD(, module) modules; /* modules in this file */
101 void* priv; /* implementation data */
102
103 struct linker_file_ops* ops;
104 };
105
106 /*
107 * Object implementing a class of file (a.out, elf, etc.)
108 */
109 typedef struct linker_class *linker_class_t;
110 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
111
112 struct linker_class_ops {
113 /*
114 * Load a file, returning the new linker_file_t in *result. If
115 * the class does not recognise the file type, zero should be
116 * returned, without modifying *result. If the file is
117 * recognised, the file should be loaded, *result set to the new
118 * file and zero returned. If some other error is detected an
119 * appropriate errno should be returned.
120 */
121 int (*load_file)(const char* filename, linker_file_t* result);
122 };
123
124 struct linker_class {
125 TAILQ_ENTRY(linker_class) link; /* list of all file classes */
126 const char* desc; /* description (e.g. "a.out") */
127 void* priv; /* implementation data */
128
129 struct linker_class_ops *ops;
130 };
131
132 /*
133 * The file which is currently loading. Used to register modules with
134 * the files which contain them.
135 */
136 extern linker_file_t linker_current_file;
137
138 /*
139 * The "file" for the kernel.
140 */
141 extern linker_file_t linker_kernel_file;
142
143 /*
144 * Add a new file class to the linker.
145 */
146 int linker_add_class(const char* _desc, void* _priv,
147 struct linker_class_ops* _ops);
148
149 /*
150 * Load a file, trying each file class until one succeeds.
151 */
152 int linker_load_file(const char* _filename, linker_file_t* _result);
153
154 /*
155 * Find a currently loaded file given its filename.
156 */
157 linker_file_t linker_find_file_by_name(const char* _filename);
158
159 /*
160 * Find a currently loaded file given its file id.
161 */
162 linker_file_t linker_find_file_by_id(int _fileid);
163
164 /*
165 * Called from a class handler when a file is laoded.
166 */
167 linker_file_t linker_make_file(const char* _filename, void* _priv,
168 struct linker_file_ops* _ops);
169
170 /*
171 * Unload a file, freeing up memory.
172 */
173 int linker_file_unload(linker_file_t _file);
174
175 /*
176 * Add a dependancy to a file.
177 */
178 int linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep);
179
180 /*
181 * Lookup a symbol in a file. If deps is TRUE, look in dependancies
182 * if not found in file.
183 */
184 caddr_t linker_file_lookup_symbol(linker_file_t _file, const char* _name,
185 int _deps);
186
187 /*
188 * Search the linker path for the module. Return the full pathname in
189 * a malloc'ed buffer.
190 */
191 char *linker_search_path(const char *_filename);
192
193 /*
194 * DDB Helpers, tuned specifically for ddb/db_kld.c
195 */
196 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
197 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
198 long *_diffp);
199 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
200
201
202 #endif /* _KERNEL */
203
204 /*
205 * Module information subtypes
206 */
207 #define MODINFO_END 0x0000 /* End of list */
208 #define MODINFO_NAME 0x0001 /* Name of module (string) */
209 #define MODINFO_TYPE 0x0002 /* Type of module (string) */
210 #define MODINFO_ADDR 0x0003 /* Loaded address */
211 #define MODINFO_SIZE 0x0004 /* Size of module */
212 #define MODINFO_EMPTY 0x0005 /* Has been deleted */
213 #define MODINFO_ARGS 0x0006 /* Parameters string */
214 #define MODINFO_METADATA 0x8000 /* Module-specfic */
215
216 #define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */
217 #define MODINFOMD_ELFHDR 0x0002 /* ELF header */
218 #define MODINFOMD_SSYM 0x0003 /* start of symbols */
219 #define MODINFOMD_ESYM 0x0004 /* end of symbols */
220 #define MODINFOMD_DYNAMIC 0x0005 /* _DYNAMIC pointer */
221 #define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */
222
223 #define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */
224
225 #ifdef _KERNEL
226
227 /*
228 * Module lookup
229 */
230 extern caddr_t preload_metadata;
231 extern caddr_t preload_search_by_name(const char *_name);
232 extern caddr_t preload_search_by_type(const char *_type);
233 extern caddr_t preload_search_next_name(caddr_t _base);
234 extern caddr_t preload_search_info(caddr_t _mod, int _inf);
235 extern void preload_delete_name(const char *_name);
236 extern void preload_bootstrap_relocate(vm_offset_t _offset);
237
238 #ifdef KLD_DEBUG
239
240 extern int kld_debug;
241 #define KLD_DEBUG_FILE 1 /* file load/unload */
242 #define KLD_DEBUG_SYM 2 /* symbol lookup */
243
244 #define KLD_DPF(cat, args) \
245 do { \
246 if (kld_debug & KLD_DEBUG_##cat) printf args; \
247 } while (0)
248
249 #else
250
251 #define KLD_DPF(cat, args)
252
253 #endif
254
255 /* Support functions */
256 int elf_reloc(linker_file_t _lf, const void *_rel, int _type,
257 const char *_sym);
258 /* values for type */
259 #define ELF_RELOC_REL 1
260 #define ELF_RELOC_RELA 2
261
262 #endif /* _KERNEL */
263
264 struct kld_file_stat {
265 int version; /* set to sizeof(linker_file_stat) */
266 char name[MAXPATHLEN];
267 int refs;
268 int id;
269 caddr_t address; /* load address */
270 size_t size; /* size in bytes */
271 };
272
273 struct kld_sym_lookup {
274 int version; /* set to sizeof(struct kld_sym_lookup) */
275 char *symname; /* Symbol name we are looking up */
276 u_long symvalue;
277 size_t symsize;
278 };
279 #define KLDSYM_LOOKUP 1
280
281 #ifndef _KERNEL
282
283 #include <sys/cdefs.h>
284
285 __BEGIN_DECLS
286 int kldload(const char* _file);
287 int kldunload(int _fileid);
288 int kldfind(const char* _file);
289 int kldnext(int _fileid);
290 int kldstat(int _fileid, struct kld_file_stat* _stat);
291 int kldfirstmod(int _fileid);
292 int kldsym(int _fileid, int _cmd, void *_data);
293 __END_DECLS
294
295 #endif
296
297 #endif /* !_SYS_LINKER_H_ */
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