xref: /freebsd/sys/sys/linker.h (revision 817420dc8eac7df799c78f5309b75092b7f7cd40)
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 /*
42  * Object representing a file which has been loaded by the linker.
43  */
44 typedef struct linker_file* linker_file_t;
45 typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
46 
47 typedef caddr_t linker_sym_t;		/* opaque symbol */
48 typedef c_caddr_t c_linker_sym_t;	/* const opaque symbol */
49 
50 /*
51  * expanded out linker_sym_t
52  */
53 typedef struct linker_symval {
54     const char*		name;
55     caddr_t		value;
56     size_t		size;
57 } linker_symval_t;
58 
59 struct common_symbol {
60     STAILQ_ENTRY(common_symbol) link;
61     char*		name;
62     caddr_t		address;
63 };
64 
65 struct linker_file {
66     KOBJ_FIELDS;
67     int			refs;		/* reference count */
68     int			userrefs;	/* kldload(2) count */
69     int			flags;
70 #define LINKER_FILE_LINKED	0x1	/* file has been fully linked */
71     TAILQ_ENTRY(linker_file) link;	/* list of all loaded files */
72     char*		filename;	/* file which was loaded */
73     int			id;		/* unique id */
74     caddr_t		address;	/* load address */
75     size_t		size;		/* size of file */
76     int			ndeps;		/* number of dependancies */
77     linker_file_t*	deps;		/* list of dependancies */
78     STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
79     TAILQ_HEAD(, module) modules;	/* modules in this file */
80     TAILQ_ENTRY(linker_file) loaded;	/* preload dependency support */
81 };
82 
83 /*
84  * Object implementing a class of file (a.out, elf, etc.)
85  */
86 typedef struct linker_class *linker_class_t;
87 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
88 
89 struct linker_class {
90     KOBJ_CLASS_FIELDS;
91     TAILQ_ENTRY(linker_class) link;	/* list of all file classes */
92 };
93 
94 /*
95  * The "file" for the kernel.
96  */
97 extern linker_file_t	linker_kernel_file;
98 
99 /*
100  * Add a new file class to the linker.
101  */
102 int linker_add_class(linker_class_t _cls);
103 
104 /*
105  * Load a file, trying each file class until one succeeds.
106  */
107 int linker_load_file(const char* _filename, linker_file_t* _result);
108 
109 /*
110  * Find a currently loaded file given its filename.
111  */
112 linker_file_t linker_find_file_by_name(const char* _filename);
113 
114 /*
115  * Find a currently loaded file given its file id.
116  */
117 linker_file_t linker_find_file_by_id(int _fileid);
118 
119 /*
120  * Called from a class handler when a file is laoded.
121  */
122 linker_file_t linker_make_file(const char* _filename, linker_class_t _cls);
123 
124 /*
125  * Unload a file, freeing up memory.
126  */
127 int linker_file_unload(linker_file_t _file);
128 
129 /*
130  * Add a dependancy to a file.
131  */
132 int linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep);
133 
134 /*
135  * Lookup a symbol in a file.  If deps is TRUE, look in dependancies
136  * if not found in file.
137  */
138 caddr_t linker_file_lookup_symbol(linker_file_t _file, const char* _name,
139 				  int _deps);
140 
141 /*
142  * This routine is responsible for finding dependencies of userland
143  * initiated kldload(2)'s of files.
144  */
145 int linker_load_dependancies(linker_file_t _lf);
146 
147 /*
148  * DDB Helpers, tuned specifically for ddb/db_kld.c
149  */
150 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
151 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
152 			     long *_diffp);
153 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
154 
155 
156 #endif	/* _KERNEL */
157 
158 /*
159  * Module information subtypes
160  */
161 #define MODINFO_END		0x0000		/* End of list */
162 #define MODINFO_NAME		0x0001		/* Name of module (string) */
163 #define MODINFO_TYPE		0x0002		/* Type of module (string) */
164 #define MODINFO_ADDR		0x0003		/* Loaded address */
165 #define MODINFO_SIZE		0x0004		/* Size of module */
166 #define MODINFO_EMPTY		0x0005		/* Has been deleted */
167 #define MODINFO_ARGS		0x0006		/* Parameters string */
168 #define MODINFO_METADATA	0x8000		/* Module-specfic */
169 
170 #define MODINFOMD_AOUTEXEC	0x0001		/* a.out exec header */
171 #define MODINFOMD_ELFHDR	0x0002		/* ELF header */
172 #define MODINFOMD_SSYM		0x0003		/* start of symbols */
173 #define MODINFOMD_ESYM		0x0004		/* end of symbols */
174 #define MODINFOMD_DYNAMIC	0x0005		/* _DYNAMIC pointer */
175 #define MODINFOMD_NOCOPY	0x8000		/* don't copy this metadata to the kernel */
176 
177 #define MODINFOMD_DEPLIST	(0x4001 | MODINFOMD_NOCOPY)	/* depends on */
178 
179 #ifdef _KERNEL
180 
181 /*
182  * Module lookup
183  */
184 extern caddr_t		preload_metadata;
185 extern caddr_t		preload_search_by_name(const char *_name);
186 extern caddr_t		preload_search_by_type(const char *_type);
187 extern caddr_t		preload_search_next_name(caddr_t _base);
188 extern caddr_t		preload_search_info(caddr_t _mod, int _inf);
189 extern void		preload_delete_name(const char *_name);
190 extern void		preload_bootstrap_relocate(vm_offset_t _offset);
191 
192 #ifdef KLD_DEBUG
193 
194 extern int kld_debug;
195 #define KLD_DEBUG_FILE	1	/* file load/unload */
196 #define KLD_DEBUG_SYM	2	/* symbol lookup */
197 
198 #define KLD_DPF(cat, args)					\
199 	do {							\
200 		if (kld_debug & KLD_DEBUG_##cat) printf args;	\
201 	} while (0)
202 
203 #else
204 
205 #define KLD_DPF(cat, args)
206 
207 #endif
208 
209 /* Support functions */
210 int	elf_reloc(linker_file_t _lf, const void *_rel, int _type,
211 		  const char *_sym);
212 /* values for type */
213 #define ELF_RELOC_REL	1
214 #define ELF_RELOC_RELA	2
215 
216 #endif /* _KERNEL */
217 
218 struct kld_file_stat {
219     int		version;	/* set to sizeof(linker_file_stat) */
220     char        name[MAXPATHLEN];
221     int		refs;
222     int		id;
223     caddr_t	address;	/* load address */
224     size_t	size;		/* size in bytes */
225 };
226 
227 struct kld_sym_lookup {
228     int		version;	/* set to sizeof(struct kld_sym_lookup) */
229     char	*symname;	/* Symbol name we are looking up */
230     u_long	symvalue;
231     size_t	symsize;
232 };
233 #define KLDSYM_LOOKUP	1
234 
235 #ifndef _KERNEL
236 
237 #include <sys/cdefs.h>
238 
239 __BEGIN_DECLS
240 int	kldload(const char* _file);
241 int	kldunload(int _fileid);
242 int	kldfind(const char* _file);
243 int	kldnext(int _fileid);
244 int	kldstat(int _fileid, struct kld_file_stat* _stat);
245 int	kldfirstmod(int _fileid);
246 int	kldsym(int _fileid, int _cmd, void *_data);
247 __END_DECLS
248 
249 #endif
250 
251 #endif /* !_SYS_LINKER_H_ */
252