2 * Copyright (c) 1997 Doug Rabson
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
26 * $FreeBSD: src/sys/sys/linker.h,v 1.17.2.1 2002/03/11 01:13:53 dd Exp $
27 * $DragonFly: src/sys/sys/linker.h,v 1.11 2008/02/06 22:37:46 nth Exp $
30 #ifndef _SYS_LINKER_H_
31 #define _SYS_LINKER_H_
34 #include <sys/types.h>
37 #include <sys/param.h>
43 #include <sys/queue.h>
45 #ifndef _MACHINE_ELF_H_
46 #include <machine/elf.h>
49 #include <sys/module.h>
52 MALLOC_DECLARE(M_LINKER);
56 * Object representing a file which has been loaded by the linker.
58 typedef struct linker_file* linker_file_t;
59 typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
61 typedef caddr_t linker_sym_t; /* opaque symbol */
62 typedef c_caddr_t c_linker_sym_t; /* const opaque symbol */
65 * expanded out linker_sym_t
67 typedef struct linker_symval {
73 struct linker_file_ops {
75 * Lookup a symbol in the file's symbol table. If the symbol is
76 * not found then return ENOENT, otherwise zero. If the symbol
77 * found is a common symbol, return with *address set to zero and
78 * *size set to the size of the common space required. Otherwise
79 * set *address the value of the symbol.
81 int (*lookup_symbol)(linker_file_t, const char* name,
84 int (*symbol_values)(linker_file_t, c_linker_sym_t,
87 int (*search_symbol)(linker_file_t, caddr_t value,
88 c_linker_sym_t* sym, long* diffp);
91 * Completes the loading task started in preload_file.
93 int (*preload_finish)(linker_file_t);
96 * Unload a file, releasing dependancies and freeing storage.
98 void (*unload)(linker_file_t);
100 int (*lookup_set)(linker_file_t, const char *name,
101 void ***firstp, void ***lastp, int *countp);
104 struct common_symbol {
105 STAILQ_ENTRY(common_symbol) link;
111 int refs; /* reference count */
112 int userrefs; /* kldload(2) count */
114 #define LINKER_FILE_LINKED 0x1 /* file has been fully linked */
115 TAILQ_ENTRY(linker_file) link; /* list of all loaded files */
116 char* filename; /* file which was loaded */
117 int id; /* unique id */
118 caddr_t address; /* load address */
119 size_t size; /* size of file */
120 int ndeps; /* number of dependancies */
121 linker_file_t* deps; /* list of dependancies */
122 STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
123 TAILQ_HEAD(, module) modules; /* modules in this file */
124 TAILQ_ENTRY(linker_file) loaded; /* preload dependency support */
125 void* priv; /* implementation data */
127 struct linker_file_ops* ops;
131 * Object implementing a class of file (a.out, elf, etc.)
133 typedef struct linker_class *linker_class_t;
134 typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
136 struct linker_class_ops {
138 * Load a file, returning the new linker_file_t in *result. If
139 * the class does not recognise the file type, zero should be
140 * returned, without modifying *result. If the file is
141 * recognised, the file should be loaded, *result set to the new
142 * file and zero returned. If some other error is detected an
143 * appropriate errno should be returned.
145 int (*load_file)(const char *filename, linker_file_t *result);
147 * Same as load_file, but does not load dependencies. Necessary
148 * for tentatively loading (loader-)preloaded modules.
150 int (*preload_file)(const char *filename, linker_file_t *result);
153 struct linker_class {
154 TAILQ_ENTRY(linker_class) link; /* list of all file classes */
155 const char* desc; /* description (e.g. "a.out") */
156 void* priv; /* implementation data */
158 struct linker_class_ops *ops;
162 * The file which is currently loading. Used to register modules with
163 * the files which contain them.
165 extern linker_file_t linker_current_file;
168 * The "file" for the kernel.
170 extern linker_file_t linker_kernel_file;
173 * Add a new file class to the linker.
175 int linker_add_class(const char* _desc, void* _priv,
176 struct linker_class_ops* _ops);
179 * Load a file, trying each file class until one succeeds.
181 int linker_load_file(const char *_filename, linker_file_t *_result);
184 * Find a currently loaded file given its filename.
186 linker_file_t linker_find_file_by_name(const char* _filename);
189 * Find a currently loaded file given its file id.
191 linker_file_t linker_find_file_by_id(int _fileid);
194 * Called from a class handler when a file is laoded.
196 linker_file_t linker_make_file(const char* _filename, void* _priv,
197 struct linker_file_ops* _ops);
200 * Unload a file, freeing up memory.
202 int linker_file_unload(linker_file_t _file);
205 * Add a dependancy to a file.
207 void linker_file_add_dependancy(linker_file_t _file, linker_file_t _dep);
209 int linker_load_dependencies(linker_file_t lf);
212 * Lookup a symbol in a file. If deps is TRUE, look in dependancies
213 * if not found in file. The symbol's value is returned in the
214 * caddr_t. An error is returned, 0 if no error occured.
216 int linker_file_lookup_symbol(linker_file_t _file, const char* _name,
217 int _deps, caddr_t *);
221 * Lookup a linker set in a file. Return pointers to the first entry,
222 * last + 1, and count of entries. Use: for (p = start; p < stop; p++) {}
223 * void *start is really: "struct yoursetmember ***start;"
225 int linker_file_lookup_set(linker_file_t _file, const char *_name,
226 void *_start, void *_stop, int *_count);
229 * Search the linker path for the module. Return the full pathname in
230 * a malloc'ed buffer.
232 char *linker_search_path(const char *_filename);
234 int linker_reference_module(const char *modname, struct mod_depend *verinfo,
235 linker_file_t *retult);
236 int linker_release_module(const char *modname, struct mod_depend *verinfo,
240 * DDB Helpers, tuned specifically for ddb/db_kld.c
242 int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
243 int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
245 int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
251 * Module information subtypes
253 #define MODINFO_END 0x0000 /* End of list */
254 #define MODINFO_NAME 0x0001 /* Name of module (string) */
255 #define MODINFO_TYPE 0x0002 /* Type of module (string) */
256 #define MODINFO_ADDR 0x0003 /* Loaded address */
257 #define MODINFO_SIZE 0x0004 /* Size of module */
258 #define MODINFO_EMPTY 0x0005 /* Has been deleted */
259 #define MODINFO_ARGS 0x0006 /* Parameters string */
260 #define MODINFO_METADATA 0x8000 /* Module-specfic */
262 #define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */
263 #define MODINFOMD_ELFHDR 0x0002 /* ELF header */
264 #define MODINFOMD_SSYM 0x0003 /* start of symbols */
265 #define MODINFOMD_ESYM 0x0004 /* end of symbols */
266 #define MODINFOMD_DYNAMIC 0x0005 /* _DYNAMIC pointer */
267 #define MODINFOMD_ENVP 0x0006 /* (from 5.x) envp[] */
268 #define MODINFOMD_HOWTO 0x0007 /* (from 5.x) boothowto */
269 #define MODINFOMD_KERNEND 0x0008 /* (from 5.x) kernend */
270 #define MODINFOMD_SHDR 0x0009 /* section header table */
271 #define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */
273 #define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */
276 #define MD_FETCH(mdp, info, type) ({ \
278 __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
283 #define LINKER_HINTS_VERSION 1 /* linker.hints file version */
290 extern caddr_t preload_metadata;
291 extern caddr_t preload_search_by_name(const char *);
292 extern caddr_t preload_search_by_type(const char *);
293 extern caddr_t preload_search_next_name(caddr_t);
294 extern caddr_t preload_search_info(caddr_t, int);
295 extern void preload_delete_name(const char *);
296 extern void preload_bootstrap_relocate(vm_offset_t);
297 extern struct mod_metadata *find_mod_metadata(const char *);
301 extern int kld_debug;
302 #define KLD_DEBUG_FILE 1 /* file load/unload */
303 #define KLD_DEBUG_SYM 2 /* symbol lookup */
305 #define KLD_DPF(cat, args) \
307 if (kld_debug & KLD_DEBUG_##cat) kprintf args; \
312 #define KLD_DPF(cat, args)
316 typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *);
318 /* Support functions */
319 int elf_reloc(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn);
320 int elf_reloc_local(linker_file_t, Elf_Addr, const void *, int, elf_lookup_fn);
321 Elf_Addr elf_relocaddr(linker_file_t, Elf_Addr);
323 /* values for type */
324 #define ELF_RELOC_REL 1
325 #define ELF_RELOC_RELA 2
329 struct kld_file_stat {
330 int version; /* set to sizeof(linker_file_stat) */
331 char name[MAXPATHLEN];
334 caddr_t address; /* load address */
335 size_t size; /* size in bytes */
338 struct kld_sym_lookup {
339 int version; /* set to sizeof(struct kld_sym_lookup) */
340 const char *symname; /* Symbol name we are looking up */
345 #define KLDSYM_LOOKUP 1
349 #ifndef _SYS_CDEFS_H_
350 #include <sys/cdefs.h>
354 int kldload(const char *);
356 int kldfind(const char *);
358 int kldstat(int, struct kld_file_stat *);
359 int kldfirstmod(int);
360 int kldsym(int, int, void *);
365 #endif /* !_SYS_LINKER_H_ */