xref: /freebsd/sys/sys/linker.h (revision 2dd94b045e8c069c1a748d40d30d979e30e02fc9)
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_flags(caddr_t value, char *buf, u_int buflen,
192     long *offset, int flags);
193 int linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
194     long *offset);
195 
196 
197 /* HWPMC helper */
198 void *linker_hwpmc_list_objects(void);
199 
200 #endif	/* _KERNEL */
201 
202 /*
203  * Module information subtypes
204  */
205 #define MODINFO_END		0x0000		/* End of list */
206 #define MODINFO_NAME		0x0001		/* Name of module (string) */
207 #define MODINFO_TYPE		0x0002		/* Type of module (string) */
208 #define MODINFO_ADDR		0x0003		/* Loaded address */
209 #define MODINFO_SIZE		0x0004		/* Size of module */
210 #define MODINFO_EMPTY		0x0005		/* Has been deleted */
211 #define MODINFO_ARGS		0x0006		/* Parameters string */
212 #define MODINFO_METADATA	0x8000		/* Module-specfic */
213 
214 #define MODINFOMD_AOUTEXEC	0x0001		/* a.out exec header */
215 #define MODINFOMD_ELFHDR	0x0002		/* ELF header */
216 #define MODINFOMD_SSYM		0x0003		/* start of symbols */
217 #define MODINFOMD_ESYM		0x0004		/* end of symbols */
218 #define MODINFOMD_DYNAMIC	0x0005		/* _DYNAMIC pointer */
219 /* These values are MD on these two platforms */
220 #if !defined(__sparc64__) && !defined(__powerpc__)
221 #define MODINFOMD_ENVP		0x0006		/* envp[] */
222 #define MODINFOMD_HOWTO		0x0007		/* boothowto */
223 #define MODINFOMD_KERNEND	0x0008		/* kernend */
224 #endif
225 #define MODINFOMD_SHDR		0x0009		/* section header table */
226 #define MODINFOMD_CTORS_ADDR	0x000a		/* address of .ctors */
227 #define MODINFOMD_CTORS_SIZE	0x000b		/* size of .ctors */
228 #define MODINFOMD_FW_HANDLE	0x000c		/* Firmware dependent handle */
229 #define MODINFOMD_KEYBUF	0x000d		/* Crypto key intake buffer */
230 #define MODINFOMD_NOCOPY	0x8000		/* don't copy this metadata to the kernel */
231 
232 #define MODINFOMD_DEPLIST	(0x4001 | MODINFOMD_NOCOPY)	/* depends on */
233 
234 #ifdef _KERNEL
235 #define MD_FETCH(mdp, info, type) ({ \
236 	type *__p; \
237 	__p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
238 	__p ? *__p : 0; \
239 })
240 #endif
241 
242 #define	LINKER_HINTS_VERSION	1		/* linker.hints file version */
243 #define	LINKER_HINTS_MAX	(1 << 20)	/* Allow at most 1MB for linker.hints */
244 
245 #ifdef _KERNEL
246 
247 /*
248  * Module lookup
249  */
250 extern vm_offset_t	preload_addr_relocate;
251 extern caddr_t		preload_metadata;
252 
253 extern void *		preload_fetch_addr(caddr_t _mod);
254 extern size_t		preload_fetch_size(caddr_t _mod);
255 extern caddr_t		preload_search_by_name(const char *_name);
256 extern caddr_t		preload_search_by_type(const char *_type);
257 extern caddr_t		preload_search_next_name(caddr_t _base);
258 extern caddr_t		preload_search_info(caddr_t _mod, int _inf);
259 extern void		preload_delete_name(const char *_name);
260 extern void		preload_bootstrap_relocate(vm_offset_t _offset);
261 
262 #ifdef KLD_DEBUG
263 
264 extern int kld_debug;
265 #define KLD_DEBUG_FILE	1	/* file load/unload */
266 #define KLD_DEBUG_SYM	2	/* symbol lookup */
267 
268 #define KLD_DPF(cat, args)					\
269 	do {							\
270 		if (kld_debug & KLD_DEBUG_##cat) printf args;	\
271 	} while (0)
272 
273 #else
274 
275 #define KLD_DPF(cat, args)
276 
277 #endif
278 
279 typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *);
280 
281 /* Support functions */
282 bool	elf_is_ifunc_reloc(Elf_Size r_info);
283 int	elf_reloc(linker_file_t _lf, Elf_Addr base, const void *_rel,
284 	    int _type, elf_lookup_fn _lu);
285 int	elf_reloc_local(linker_file_t _lf, Elf_Addr base, const void *_rel,
286 	    int _type, elf_lookup_fn _lu);
287 Elf_Addr elf_relocaddr(linker_file_t _lf, Elf_Addr addr);
288 const Elf_Sym *elf_get_sym(linker_file_t _lf, Elf_Size _symidx);
289 const char *elf_get_symname(linker_file_t _lf, Elf_Size _symidx);
290 void	link_elf_ireloc(caddr_t kmdp);
291 
292 typedef struct linker_ctf {
293 	const uint8_t 	*ctftab;	/* Decompressed CTF data. */
294 	int 		ctfcnt;		/* Number of CTF data bytes. */
295 	const Elf_Sym	*symtab;	/* Ptr to the symbol table. */
296 	int		nsym;		/* Number of symbols. */
297 	const char	*strtab;	/* Ptr to the string table. */
298 	int 		strcnt;		/* Number of string bytes. */
299 	uint32_t	**ctfoffp;	/* Ptr to array of obj/fnc offsets. */
300 	uint32_t	**typoffp;	/* Ptr to array of type offsets. */
301 	long		*typlenp;	/* Ptr to number of type data entries. */
302 } linker_ctf_t;
303 
304 int	linker_ctf_get(linker_file_t, linker_ctf_t *);
305 
306 int elf_cpu_load_file(linker_file_t);
307 int elf_cpu_unload_file(linker_file_t);
308 int elf_cpu_parse_dynamic(linker_file_t, Elf_Dyn *);
309 
310 /* values for type */
311 #define ELF_RELOC_REL	1
312 #define ELF_RELOC_RELA	2
313 
314 /*
315  * This is version 1 of the KLD file status structure. It is identified
316  * by its _size_ in the version field.
317  */
318 struct kld_file_stat_1 {
319     int		version;	/* set to sizeof(struct kld_file_stat_1) */
320     char        name[MAXPATHLEN];
321     int		refs;
322     int		id;
323     caddr_t	address;	/* load address */
324     size_t	size;		/* size in bytes */
325 };
326 #endif /* _KERNEL */
327 
328 struct kld_file_stat {
329     int		version;	/* set to sizeof(struct kld_file_stat) */
330     char        name[MAXPATHLEN];
331     int		refs;
332     int		id;
333     caddr_t	address;	/* load address */
334     size_t	size;		/* size in bytes */
335     char        pathname[MAXPATHLEN];
336 };
337 
338 struct kld_sym_lookup {
339     int		version;	/* set to sizeof(struct kld_sym_lookup) */
340     char	*symname;	/* Symbol name we are looking up */
341     u_long	symvalue;
342     size_t	symsize;
343 };
344 #define KLDSYM_LOOKUP	1
345 
346 /*
347  * Flags for kldunloadf() and linker_file_unload()
348  */
349 #define LINKER_UNLOAD_NORMAL	0
350 #define LINKER_UNLOAD_FORCE	1
351 
352 #ifndef _KERNEL
353 
354 #include <sys/cdefs.h>
355 
356 __BEGIN_DECLS
357 int	kldload(const char* _file);
358 int	kldunload(int _fileid);
359 int	kldunloadf(int _fileid, int flags);
360 int	kldfind(const char* _file);
361 int	kldnext(int _fileid);
362 int	kldstat(int _fileid, struct kld_file_stat* _stat);
363 int	kldfirstmod(int _fileid);
364 int	kldsym(int _fileid, int _cmd, void *_data);
365 __END_DECLS
366 
367 #endif
368 
369 #endif /* !_SYS_LINKER_H_ */
370