FreeBSD/Linux Kernel Cross Reference
sys/sys/linker.h
1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3 *
4 * Copyright (c) 1997-2000 Doug Rabson
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 *
28 * $FreeBSD$
29 */
30
31 #ifndef _SYS_LINKER_H_
32 #define _SYS_LINKER_H_
33
34 #ifdef _KERNEL
35
36 #include <machine/elf.h>
37 #include <sys/kobj.h>
38
39 #ifdef MALLOC_DECLARE
40 MALLOC_DECLARE(M_LINKER);
41 #endif
42
43 struct mod_depend;
44
45 /*
46 * Object representing a file which has been loaded by the linker.
47 */
48 typedef struct linker_file* linker_file_t;
49 typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
50
51 typedef caddr_t linker_sym_t; /* opaque symbol */
52 typedef c_caddr_t c_linker_sym_t; /* const opaque symbol */
53 typedef int (*linker_function_name_callback_t)(const char *, void *);
54
55 /*
56 * expanded out linker_sym_t
57 */
58 typedef struct linker_symval {
59 const char* name;
60 caddr_t value;
61 size_t size;
62 } linker_symval_t;
63
64 typedef int (*linker_function_nameval_callback_t)(linker_file_t, int, linker_symval_t *, void *);
65
66 struct common_symbol {
67 STAILQ_ENTRY(common_symbol) link;
68 char* name;
69 caddr_t address;
70 };
71
72 struct linker_file {
73 KOBJ_FIELDS;
74 int refs; /* reference count */
75 int userrefs; /* kldload(2) count */
76 int flags;
77 #define LINKER_FILE_LINKED 0x1 /* file has been fully linked */
78 #define LINKER_FILE_MODULES 0x2 /* file has >0 modules at preload */
79 TAILQ_ENTRY(linker_file) link; /* list of all loaded files */
80 char* filename; /* file which was loaded */
81 char* pathname; /* file name with full path */
82 int id; /* unique id */
83 caddr_t address; /* load address */
84 size_t size; /* size of file */
85 caddr_t ctors_addr; /* address of .ctors */
86 size_t ctors_size; /* size of .ctors */
87 int ndeps; /* number of dependencies */
88 linker_file_t* deps; /* list of dependencies */
89 STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
90 TAILQ_HEAD(, module) modules; /* modules in this file */
91 TAILQ_ENTRY(linker_file) loaded; /* preload dependency support */
92 int loadcnt; /* load counter value */
93
94 /*
95 * Function Boundary Tracing (FBT) or Statically Defined Tracing (SDT)
96 * fields.
97 */
98 int nenabled; /* number of enabled probes. */
99 int fbt_nentries; /* number of fbt entries created. */
100
101 #ifdef __arm__
102 caddr_t exidx_addr; /* Unwind data index table start */
103 size_t exidx_size; /* Unwind data index table size */
104 #endif
105 };
106
107 /*
108 * Object implementing a class of file (a.out, elf, etc.)
109 */
110 typedef struct linker_class *linker_class_t;
111 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
112
113 struct linker_class {
114 KOBJ_CLASS_FIELDS;
115 TAILQ_ENTRY(linker_class) link; /* list of all file classes */
116 };
117
118 /*
119 * Function type used when iterating over the list of linker files.
120 */
121 typedef int linker_predicate_t(linker_file_t, void *);
122
123 /*
124 * The "file" for the kernel.
125 */
126 extern linker_file_t linker_kernel_file;
127
128 /*
129 * Obtain a reference to a module, loading it if required.
130 */
131 int linker_reference_module(const char* _modname, struct mod_depend *_verinfo,
132 linker_file_t* _result);
133
134 /*
135 * Release a reference to a module, unloading it if there are no more
136 * references. Note that one should either provide a module name and
137 * optional version info or a linker file, but not both.
138 */
139 int linker_release_module(const char *_modname, struct mod_depend *_verinfo,
140 linker_file_t _file);
141
142 /*
143 * Iterate over all of the currently loaded linker files calling the
144 * predicate function while the function returns 0. Returns the value
145 * returned by the last predicate function.
146 */
147 int linker_file_foreach(linker_predicate_t *_predicate, void *_context);
148
149 /*
150 * Lookup a symbol in a file. If deps is TRUE, look in dependencies
151 * if not found in file.
152 */
153 caddr_t linker_file_lookup_symbol(linker_file_t _file, const char* _name,
154 int _deps);
155
156 /*
157 * Lookup a linker set in a file. Return pointers to the first entry,
158 * last + 1, and count of entries. Use: for (p = start; p < stop; p++) {}
159 * void *start is really: "struct yoursetmember ***start;"
160 */
161 int linker_file_lookup_set(linker_file_t _file, const char *_name,
162 void *_start, void *_stop, int *_count);
163
164 /*
165 * List all functions in a file.
166 */
167 int linker_file_function_listall(linker_file_t,
168 linker_function_nameval_callback_t, void *);
169
170 /*
171 * Functions solely for use by the linker class handlers.
172 */
173 int linker_add_class(linker_class_t _cls);
174 int linker_file_unload(linker_file_t _file, int flags);
175 int linker_load_dependencies(linker_file_t _lf);
176 linker_file_t linker_make_file(const char* _filename, linker_class_t _cls);
177
178 /*
179 * DDB Helpers, tuned specifically for ddb/db_kld.c
180 */
181 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
182 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
183 long *_diffp);
184 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
185 int linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
186 long *offset);
187
188 /*
189 * stack(9) helper for situations where kernel locking is required.
190 */
191 int linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
192 long *offset);
193
194
195 /* HWPMC helper */
196 void *linker_hwpmc_list_objects(void);
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_ARGS 0x0006 /* Parameters string */
210 #define MODINFO_METADATA 0x8000 /* Module-specfic */
211
212 #define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */
213 #define MODINFOMD_ELFHDR 0x0002 /* ELF header */
214 #define MODINFOMD_SSYM 0x0003 /* start of symbols */
215 #define MODINFOMD_ESYM 0x0004 /* end of symbols */
216 #define MODINFOMD_DYNAMIC 0x0005 /* _DYNAMIC pointer */
217 /* These values are MD on these two platforms */
218 #if !defined(__sparc64__) && !defined(__powerpc__)
219 #define MODINFOMD_ENVP 0x0006 /* envp[] */
220 #define MODINFOMD_HOWTO 0x0007 /* boothowto */
221 #define MODINFOMD_KERNEND 0x0008 /* kernend */
222 #endif
223 #define MODINFOMD_SHDR 0x0009 /* section header table */
224 #define MODINFOMD_CTORS_ADDR 0x000a /* address of .ctors */
225 #define MODINFOMD_CTORS_SIZE 0x000b /* size of .ctors */
226 #define MODINFOMD_FW_HANDLE 0x000c /* Firmware dependent handle */
227 #define MODINFOMD_KEYBUF 0x000d /* Crypto key intake buffer */
228 #define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */
229
230 #define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */
231
232 #ifdef _KERNEL
233 #define MD_FETCH(mdp, info, type) ({ \
234 type *__p; \
235 __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
236 __p ? *__p : 0; \
237 })
238 #endif
239
240 #define LINKER_HINTS_VERSION 1 /* linker.hints file version */
241 #define LINKER_HINTS_MAX (1 << 20) /* Allow at most 1MB for linker.hints */
242
243 #ifdef _KERNEL
244
245 /*
246 * Module lookup
247 */
248 extern vm_offset_t preload_addr_relocate;
249 extern caddr_t preload_metadata;
250
251 extern void * preload_fetch_addr(caddr_t _mod);
252 extern size_t preload_fetch_size(caddr_t _mod);
253 extern caddr_t preload_search_by_name(const char *_name);
254 extern caddr_t preload_search_by_type(const char *_type);
255 extern caddr_t preload_search_next_name(caddr_t _base);
256 extern caddr_t preload_search_info(caddr_t _mod, int _inf);
257 extern void preload_delete_name(const char *_name);
258 extern void preload_bootstrap_relocate(vm_offset_t _offset);
259
260 #ifdef KLD_DEBUG
261
262 extern int kld_debug;
263 #define KLD_DEBUG_FILE 1 /* file load/unload */
264 #define KLD_DEBUG_SYM 2 /* symbol lookup */
265
266 #define KLD_DPF(cat, args) \
267 do { \
268 if (kld_debug & KLD_DEBUG_##cat) printf args; \
269 } while (0)
270
271 #else
272
273 #define KLD_DPF(cat, args)
274
275 #endif
276
277 typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *);
278
279 /* Support functions */
280 bool elf_is_ifunc_reloc(Elf_Size r_info);
281 int elf_reloc(linker_file_t _lf, Elf_Addr base, const void *_rel,
282 int _type, elf_lookup_fn _lu);
283 int elf_reloc_local(linker_file_t _lf, Elf_Addr base, const void *_rel,
284 int _type, elf_lookup_fn _lu);
285 Elf_Addr elf_relocaddr(linker_file_t _lf, Elf_Addr addr);
286 const Elf_Sym *elf_get_sym(linker_file_t _lf, Elf_Size _symidx);
287 const char *elf_get_symname(linker_file_t _lf, Elf_Size _symidx);
288 void link_elf_ireloc(caddr_t kmdp);
289
290 typedef struct linker_ctf {
291 const uint8_t *ctftab; /* Decompressed CTF data. */
292 int ctfcnt; /* Number of CTF data bytes. */
293 const Elf_Sym *symtab; /* Ptr to the symbol table. */
294 int nsym; /* Number of symbols. */
295 const char *strtab; /* Ptr to the string table. */
296 int strcnt; /* Number of string bytes. */
297 uint32_t **ctfoffp; /* Ptr to array of obj/fnc offsets. */
298 uint32_t **typoffp; /* Ptr to array of type offsets. */
299 long *typlenp; /* Ptr to number of type data entries. */
300 } linker_ctf_t;
301
302 int linker_ctf_get(linker_file_t, linker_ctf_t *);
303
304 int elf_cpu_load_file(linker_file_t);
305 int elf_cpu_unload_file(linker_file_t);
306
307 /* values for type */
308 #define ELF_RELOC_REL 1
309 #define ELF_RELOC_RELA 2
310
311 /*
312 * This is version 1 of the KLD file status structure. It is identified
313 * by its _size_ in the version field.
314 */
315 struct kld_file_stat_1 {
316 int version; /* set to sizeof(struct kld_file_stat_1) */
317 char name[MAXPATHLEN];
318 int refs;
319 int id;
320 caddr_t address; /* load address */
321 size_t size; /* size in bytes */
322 };
323 #endif /* _KERNEL */
324
325 struct kld_file_stat {
326 int version; /* set to sizeof(struct kld_file_stat) */
327 char name[MAXPATHLEN];
328 int refs;
329 int id;
330 caddr_t address; /* load address */
331 size_t size; /* size in bytes */
332 char pathname[MAXPATHLEN];
333 };
334
335 struct kld_sym_lookup {
336 int version; /* set to sizeof(struct kld_sym_lookup) */
337 char *symname; /* Symbol name we are looking up */
338 u_long symvalue;
339 size_t symsize;
340 };
341 #define KLDSYM_LOOKUP 1
342
343 /*
344 * Flags for kldunloadf() and linker_file_unload()
345 */
346 #define LINKER_UNLOAD_NORMAL 0
347 #define LINKER_UNLOAD_FORCE 1
348
349 #ifndef _KERNEL
350
351 #include <sys/cdefs.h>
352
353 __BEGIN_DECLS
354 int kldload(const char* _file);
355 int kldunload(int _fileid);
356 int kldunloadf(int _fileid, int flags);
357 int kldfind(const char* _file);
358 int kldnext(int _fileid);
359 int kldstat(int _fileid, struct kld_file_stat* _stat);
360 int kldfirstmod(int _fileid);
361 int kldsym(int _fileid, int _cmd, void *_data);
362 __END_DECLS
363
364 #endif
365
366 #endif /* !_SYS_LINKER_H_ */
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