xref: /freebsd/sys/sys/linker.h (revision 4f29da19bd44f0e99f021510460a81bf754c21d2)
1 /*-
2  * Copyright (c) 1997-2000 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 #include <sys/kobj.h>
36 
37 #ifdef MALLOC_DECLARE
38 MALLOC_DECLARE(M_LINKER);
39 #endif
40 
41 struct mod_depend;
42 
43 /*
44  * Object representing a file which has been loaded by the linker.
45  */
46 typedef struct linker_file* linker_file_t;
47 typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
48 
49 typedef caddr_t linker_sym_t;		/* opaque symbol */
50 typedef c_caddr_t c_linker_sym_t;	/* const opaque symbol */
51 typedef int (*linker_function_name_callback_t)(const char *, void *);
52 
53 /*
54  * expanded out linker_sym_t
55  */
56 typedef struct linker_symval {
57     const char*		name;
58     caddr_t		value;
59     size_t		size;
60 } linker_symval_t;
61 
62 struct common_symbol {
63     STAILQ_ENTRY(common_symbol) link;
64     char*		name;
65     caddr_t		address;
66 };
67 
68 struct linker_file {
69     KOBJ_FIELDS;
70     int			refs;		/* reference count */
71     int			userrefs;	/* kldload(2) count */
72     int			flags;
73 #define LINKER_FILE_LINKED	0x1	/* file has been fully linked */
74     TAILQ_ENTRY(linker_file) link;	/* list of all loaded files */
75     char*		filename;	/* file which was loaded */
76     int			id;		/* unique id */
77     caddr_t		address;	/* load address */
78     size_t		size;		/* size of file */
79     int			ndeps;		/* number of dependencies */
80     linker_file_t*	deps;		/* list of dependencies */
81     STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
82     TAILQ_HEAD(, module) modules;	/* modules in this file */
83     TAILQ_ENTRY(linker_file) loaded;	/* preload dependency support */
84 };
85 
86 /*
87  * Object implementing a class of file (a.out, elf, etc.)
88  */
89 typedef struct linker_class *linker_class_t;
90 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
91 
92 struct linker_class {
93     KOBJ_CLASS_FIELDS;
94     TAILQ_ENTRY(linker_class) link;	/* list of all file classes */
95 };
96 
97 /*
98  * The "file" for the kernel.
99  */
100 extern linker_file_t	linker_kernel_file;
101 
102 /*
103  * Add a new file class to the linker.
104  */
105 int linker_add_class(linker_class_t _cls);
106 
107 /*
108  * Load a kernel module.
109  */
110 int linker_load_module(const char *_kldname, const char *_modname,
111     struct linker_file *_parent, struct mod_depend *_verinfo,
112     struct linker_file **_lfpp);
113 
114 /*
115  * Obtain a reference to a module, loading it if required.
116  */
117 int linker_reference_module(const char* _modname, struct mod_depend *_verinfo,
118 			    linker_file_t* _result);
119 
120 /*
121  * Find a currently loaded file given its filename.
122  */
123 linker_file_t linker_find_file_by_name(const char* _filename);
124 
125 /*
126  * Find a currently loaded file given its file id.
127  */
128 linker_file_t linker_find_file_by_id(int _fileid);
129 
130 /*
131  * Called from a class handler when a file is laoded.
132  */
133 linker_file_t linker_make_file(const char* _filename, linker_class_t _cls);
134 
135 /*
136  * Unload a file, freeing up memory.
137  */
138 int linker_file_unload(linker_file_t _file, int flags);
139 
140 /*
141  * Add a dependency to a file.
142  */
143 int linker_file_add_dependency(linker_file_t _file, linker_file_t _dep);
144 
145 /*
146  * Lookup a symbol in a file.  If deps is TRUE, look in dependencies
147  * if not found in file.
148  */
149 caddr_t linker_file_lookup_symbol(linker_file_t _file, const char* _name,
150 				  int _deps);
151 
152 /*
153  * Lookup a linker set in a file.  Return pointers to the first entry,
154  * last + 1, and count of entries.  Use: for (p = start; p < stop; p++) {}
155  * void *start is really: "struct yoursetmember ***start;"
156  */
157 int linker_file_lookup_set(linker_file_t _file, const char *_name,
158 			   void *_start, void *_stop, int *_count);
159 
160 /*
161  * This routine is responsible for finding dependencies of userland
162  * initiated kldload(2)'s of files.
163  */
164 int linker_load_dependencies(linker_file_t _lf);
165 
166 /*
167  * DDB Helpers, tuned specifically for ddb/db_kld.c
168  */
169 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
170 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
171 			     long *_diffp);
172 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
173 
174 
175 /* HWPMC helper */
176 void *linker_hwpmc_list_objects(void);
177 
178 #endif	/* _KERNEL */
179 
180 /*
181  * Module information subtypes
182  */
183 #define MODINFO_END		0x0000		/* End of list */
184 #define MODINFO_NAME		0x0001		/* Name of module (string) */
185 #define MODINFO_TYPE		0x0002		/* Type of module (string) */
186 #define MODINFO_ADDR		0x0003		/* Loaded address */
187 #define MODINFO_SIZE		0x0004		/* Size of module */
188 #define MODINFO_EMPTY		0x0005		/* Has been deleted */
189 #define MODINFO_ARGS		0x0006		/* Parameters string */
190 #define MODINFO_METADATA	0x8000		/* Module-specfic */
191 
192 #define MODINFOMD_AOUTEXEC	0x0001		/* a.out exec header */
193 #define MODINFOMD_ELFHDR	0x0002		/* ELF header */
194 #define MODINFOMD_SSYM		0x0003		/* start of symbols */
195 #define MODINFOMD_ESYM		0x0004		/* end of symbols */
196 #define MODINFOMD_DYNAMIC	0x0005		/* _DYNAMIC pointer */
197 /* These values are MD on these two platforms */
198 #if !defined(__sparc64__) && !defined(__powerpc__)
199 #define MODINFOMD_ENVP		0x0006		/* envp[] */
200 #define MODINFOMD_HOWTO		0x0007		/* boothowto */
201 #define MODINFOMD_KERNEND	0x0008		/* kernend */
202 #endif
203 #define MODINFOMD_SHDR		0x0009		/* section header table */
204 #define MODINFOMD_NOCOPY	0x8000		/* don't copy this metadata to the kernel */
205 
206 #define MODINFOMD_DEPLIST	(0x4001 | MODINFOMD_NOCOPY)	/* depends on */
207 
208 #ifdef _KERNEL
209 #define MD_FETCH(mdp, info, type) ({ \
210 	type *__p; \
211 	__p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
212 	__p ? *__p : 0; \
213 })
214 #endif
215 
216 #define	LINKER_HINTS_VERSION	1		/* linker.hints file version */
217 
218 #ifdef _KERNEL
219 
220 /*
221  * Module lookup
222  */
223 extern caddr_t		preload_metadata;
224 extern caddr_t		preload_search_by_name(const char *_name);
225 extern caddr_t		preload_search_by_type(const char *_type);
226 extern caddr_t		preload_search_next_name(caddr_t _base);
227 extern caddr_t		preload_search_info(caddr_t _mod, int _inf);
228 extern void		preload_delete_name(const char *_name);
229 extern void		preload_bootstrap_relocate(vm_offset_t _offset);
230 
231 #ifdef KLD_DEBUG
232 
233 extern int kld_debug;
234 #define KLD_DEBUG_FILE	1	/* file load/unload */
235 #define KLD_DEBUG_SYM	2	/* symbol lookup */
236 
237 #define KLD_DPF(cat, args)					\
238 	do {							\
239 		if (kld_debug & KLD_DEBUG_##cat) printf args;	\
240 	} while (0)
241 
242 #else
243 
244 #define KLD_DPF(cat, args)
245 
246 #endif
247 
248 typedef Elf_Addr elf_lookup_fn(linker_file_t, Elf_Size, int);
249 
250 /* Support functions */
251 int	elf_reloc(linker_file_t _lf, Elf_Addr base, const void *_rel, int _type, elf_lookup_fn _lu);
252 int	elf_reloc_local(linker_file_t _lf, Elf_Addr base, const void *_rel, int _type, elf_lookup_fn _lu);
253 const Elf_Sym *elf_get_sym(linker_file_t _lf, Elf_Size _symidx);
254 const char *elf_get_symname(linker_file_t _lf, Elf_Size _symidx);
255 
256 int elf_cpu_load_file(linker_file_t);
257 int elf_cpu_unload_file(linker_file_t);
258 
259 /* values for type */
260 #define ELF_RELOC_REL	1
261 #define ELF_RELOC_RELA	2
262 
263 #endif /* _KERNEL */
264 
265 struct kld_file_stat {
266     int		version;	/* set to sizeof(linker_file_stat) */
267     char        name[MAXPATHLEN];
268     int		refs;
269     int		id;
270     caddr_t	address;	/* load address */
271     size_t	size;		/* size in bytes */
272 };
273 
274 struct kld_sym_lookup {
275     int		version;	/* set to sizeof(struct kld_sym_lookup) */
276     char	*symname;	/* Symbol name we are looking up */
277     u_long	symvalue;
278     size_t	symsize;
279 };
280 #define KLDSYM_LOOKUP	1
281 
282 /*
283  * Flags for kldunloadf() and linker_file_unload()
284  */
285 #define LINKER_UNLOAD_NORMAL	0
286 #define LINKER_UNLOAD_FORCE	1
287 
288 #ifndef _KERNEL
289 
290 #include <sys/cdefs.h>
291 
292 __BEGIN_DECLS
293 int	kldload(const char* _file);
294 int	kldunload(int _fileid);
295 int	kldunloadf(int _fileid, int flags);
296 int	kldfind(const char* _file);
297 int	kldnext(int _fileid);
298 int	kldstat(int _fileid, struct kld_file_stat* _stat);
299 int	kldfirstmod(int _fileid);
300 int	kldsym(int _fileid, int _cmd, void *_data);
301 __END_DECLS
302 
303 #endif
304 
305 #endif /* !_SYS_LINKER_H_ */
306