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: releng/12.0/sys/sys/linker.h 338211 2018-08-22 20:44:30Z markj $
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
102 /*
103 * Object implementing a class of file (a.out, elf, etc.)
104 */
105 typedef struct linker_class *linker_class_t;
106 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
107
108 struct linker_class {
109 KOBJ_CLASS_FIELDS;
110 TAILQ_ENTRY(linker_class) link; /* list of all file classes */
111 };
112
113 /*
114 * Function type used when iterating over the list of linker files.
115 */
116 typedef int linker_predicate_t(linker_file_t, void *);
117
118 /*
119 * The "file" for the kernel.
120 */
121 extern linker_file_t linker_kernel_file;
122
123 /*
124 * Obtain a reference to a module, loading it if required.
125 */
126 int linker_reference_module(const char* _modname, struct mod_depend *_verinfo,
127 linker_file_t* _result);
128
129 /*
130 * Release a reference to a module, unloading it if there are no more
131 * references. Note that one should either provide a module name and
132 * optional version info or a linker file, but not both.
133 */
134 int linker_release_module(const char *_modname, struct mod_depend *_verinfo,
135 linker_file_t _file);
136
137 /*
138 * Iterate over all of the currently loaded linker files calling the
139 * predicate function while the function returns 0. Returns the value
140 * returned by the last predicate function.
141 */
142 int linker_file_foreach(linker_predicate_t *_predicate, void *_context);
143
144 /*
145 * Lookup a symbol in a file. If deps is TRUE, look in dependencies
146 * if not found in file.
147 */
148 caddr_t linker_file_lookup_symbol(linker_file_t _file, const char* _name,
149 int _deps);
150
151 /*
152 * Lookup a linker set in a file. Return pointers to the first entry,
153 * last + 1, and count of entries. Use: for (p = start; p < stop; p++) {}
154 * void *start is really: "struct yoursetmember ***start;"
155 */
156 int linker_file_lookup_set(linker_file_t _file, const char *_name,
157 void *_start, void *_stop, int *_count);
158
159 /*
160 * List all functions in a file.
161 */
162 int linker_file_function_listall(linker_file_t,
163 linker_function_nameval_callback_t, void *);
164
165 /*
166 * Functions solely for use by the linker class handlers.
167 */
168 int linker_add_class(linker_class_t _cls);
169 int linker_file_unload(linker_file_t _file, int flags);
170 int linker_load_dependencies(linker_file_t _lf);
171 linker_file_t linker_make_file(const char* _filename, linker_class_t _cls);
172
173 /*
174 * DDB Helpers, tuned specifically for ddb/db_kld.c
175 */
176 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
177 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
178 long *_diffp);
179 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
180 int linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
181 long *offset);
182
183 /*
184 * stack(9) helper for situations where kernel locking is required.
185 */
186 int linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
187 long *offset);
188
189
190 /* HWPMC helper */
191 void *linker_hwpmc_list_objects(void);
192
193 #endif /* _KERNEL */
194
195 /*
196 * Module information subtypes
197 */
198 #define MODINFO_END 0x0000 /* End of list */
199 #define MODINFO_NAME 0x0001 /* Name of module (string) */
200 #define MODINFO_TYPE 0x0002 /* Type of module (string) */
201 #define MODINFO_ADDR 0x0003 /* Loaded address */
202 #define MODINFO_SIZE 0x0004 /* Size of module */
203 #define MODINFO_EMPTY 0x0005 /* Has been deleted */
204 #define MODINFO_ARGS 0x0006 /* Parameters string */
205 #define MODINFO_METADATA 0x8000 /* Module-specfic */
206
207 #define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */
208 #define MODINFOMD_ELFHDR 0x0002 /* ELF header */
209 #define MODINFOMD_SSYM 0x0003 /* start of symbols */
210 #define MODINFOMD_ESYM 0x0004 /* end of symbols */
211 #define MODINFOMD_DYNAMIC 0x0005 /* _DYNAMIC pointer */
212 /* These values are MD on these two platforms */
213 #if !defined(__sparc64__) && !defined(__powerpc__)
214 #define MODINFOMD_ENVP 0x0006 /* envp[] */
215 #define MODINFOMD_HOWTO 0x0007 /* boothowto */
216 #define MODINFOMD_KERNEND 0x0008 /* kernend */
217 #endif
218 #define MODINFOMD_SHDR 0x0009 /* section header table */
219 #define MODINFOMD_CTORS_ADDR 0x000a /* address of .ctors */
220 #define MODINFOMD_CTORS_SIZE 0x000b /* size of .ctors */
221 #define MODINFOMD_FW_HANDLE 0x000c /* Firmware dependent handle */
222 #define MODINFOMD_KEYBUF 0x000d /* Crypto key intake buffer */
223 #define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */
224
225 #define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */
226
227 #ifdef _KERNEL
228 #define MD_FETCH(mdp, info, type) ({ \
229 type *__p; \
230 __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
231 __p ? *__p : 0; \
232 })
233 #endif
234
235 #define LINKER_HINTS_VERSION 1 /* linker.hints file version */
236 #define LINKER_HINTS_MAX (1 << 20) /* Allow at most 1MB for linker.hints */
237
238 #ifdef _KERNEL
239
240 /*
241 * Module lookup
242 */
243 extern vm_offset_t preload_addr_relocate;
244 extern caddr_t preload_metadata;
245
246 extern void * preload_fetch_addr(caddr_t _mod);
247 extern size_t preload_fetch_size(caddr_t _mod);
248 extern caddr_t preload_search_by_name(const char *_name);
249 extern caddr_t preload_search_by_type(const char *_type);
250 extern caddr_t preload_search_next_name(caddr_t _base);
251 extern caddr_t preload_search_info(caddr_t _mod, int _inf);
252 extern void preload_delete_name(const char *_name);
253 extern void preload_bootstrap_relocate(vm_offset_t _offset);
254
255 #ifdef KLD_DEBUG
256
257 extern int kld_debug;
258 #define KLD_DEBUG_FILE 1 /* file load/unload */
259 #define KLD_DEBUG_SYM 2 /* symbol lookup */
260
261 #define KLD_DPF(cat, args) \
262 do { \
263 if (kld_debug & KLD_DEBUG_##cat) printf args; \
264 } while (0)
265
266 #else
267
268 #define KLD_DPF(cat, args)
269
270 #endif
271
272 typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *);
273
274 /* Support functions */
275 bool elf_is_ifunc_reloc(Elf_Size r_info);
276 int elf_reloc(linker_file_t _lf, Elf_Addr base, const void *_rel,
277 int _type, elf_lookup_fn _lu);
278 int elf_reloc_local(linker_file_t _lf, Elf_Addr base, const void *_rel,
279 int _type, elf_lookup_fn _lu);
280 Elf_Addr elf_relocaddr(linker_file_t _lf, Elf_Addr addr);
281 const Elf_Sym *elf_get_sym(linker_file_t _lf, Elf_Size _symidx);
282 const char *elf_get_symname(linker_file_t _lf, Elf_Size _symidx);
283 void link_elf_ireloc(caddr_t kmdp);
284
285 typedef struct linker_ctf {
286 const uint8_t *ctftab; /* Decompressed CTF data. */
287 int ctfcnt; /* Number of CTF data bytes. */
288 const Elf_Sym *symtab; /* Ptr to the symbol table. */
289 int nsym; /* Number of symbols. */
290 const char *strtab; /* Ptr to the string table. */
291 int strcnt; /* Number of string bytes. */
292 uint32_t **ctfoffp; /* Ptr to array of obj/fnc offsets. */
293 uint32_t **typoffp; /* Ptr to array of type offsets. */
294 long *typlenp; /* Ptr to number of type data entries. */
295 } linker_ctf_t;
296
297 int linker_ctf_get(linker_file_t, linker_ctf_t *);
298
299 int elf_cpu_load_file(linker_file_t);
300 int elf_cpu_unload_file(linker_file_t);
301
302 /* values for type */
303 #define ELF_RELOC_REL 1
304 #define ELF_RELOC_RELA 2
305
306 /*
307 * This is version 1 of the KLD file status structure. It is identified
308 * by its _size_ in the version field.
309 */
310 struct kld_file_stat_1 {
311 int version; /* set to sizeof(struct kld_file_stat_1) */
312 char name[MAXPATHLEN];
313 int refs;
314 int id;
315 caddr_t address; /* load address */
316 size_t size; /* size in bytes */
317 };
318 #endif /* _KERNEL */
319
320 struct kld_file_stat {
321 int version; /* set to sizeof(struct kld_file_stat) */
322 char name[MAXPATHLEN];
323 int refs;
324 int id;
325 caddr_t address; /* load address */
326 size_t size; /* size in bytes */
327 char pathname[MAXPATHLEN];
328 };
329
330 struct kld_sym_lookup {
331 int version; /* set to sizeof(struct kld_sym_lookup) */
332 char *symname; /* Symbol name we are looking up */
333 u_long symvalue;
334 size_t symsize;
335 };
336 #define KLDSYM_LOOKUP 1
337
338 /*
339 * Flags for kldunloadf() and linker_file_unload()
340 */
341 #define LINKER_UNLOAD_NORMAL 0
342 #define LINKER_UNLOAD_FORCE 1
343
344 #ifndef _KERNEL
345
346 #include <sys/cdefs.h>
347
348 __BEGIN_DECLS
349 int kldload(const char* _file);
350 int kldunload(int _fileid);
351 int kldunloadf(int _fileid, int flags);
352 int kldfind(const char* _file);
353 int kldnext(int _fileid);
354 int kldstat(int _fileid, struct kld_file_stat* _stat);
355 int kldfirstmod(int _fileid);
356 int kldsym(int _fileid, int _cmd, void *_data);
357 __END_DECLS
358
359 #endif
360
361 #endif /* !_SYS_LINKER_H_ */
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