1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
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
29#ifndef _SYS_LINKER_H_
30#define _SYS_LINKER_H_
31
32#include <sys/param.h>
33
34#ifdef _KERNEL
35
36#include <machine/elf.h>
37#include <sys/kobj.h>
38
39#ifdef MALLOC_DECLARE
40MALLOC_DECLARE(M_LINKER);
41#endif
42
43struct mod_depend;
44
45/*
46 * Object representing a file which has been loaded by the linker.
47 */
48typedef struct linker_file* linker_file_t;
49typedef TAILQ_HEAD(, linker_file) linker_file_list_t;
50
51typedef caddr_t linker_sym_t; /* opaque symbol */
52typedef c_caddr_t c_linker_sym_t; /* const opaque symbol */
53typedef int (*linker_function_name_callback_t)(const char *, void *);
54
55/*
56 * expanded out linker_sym_t
57 */
58typedef struct linker_symval {
59 const char* name;
60 caddr_t value;
61 size_t size;
62} linker_symval_t;
63
64typedef int (*linker_function_nameval_callback_t)(linker_file_t, int, linker_symval_t *, void *);
65
66struct common_symbol {
67 STAILQ_ENTRY(common_symbol) link;
68 char* name;
69 caddr_t address;
70};
71
72struct 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/.init_array */
86 size_t ctors_size; /* size of .ctors/.init_array */
87 enum {
88 LF_NONE = 0,
89 LF_CTORS,
90 LF_DTORS,
91 } ctors_invoked; /* have we run ctors yet? */
92 caddr_t dtors_addr; /* address of .dtors/.fini_array */
93 size_t dtors_size; /* size of .dtors/.fini_array */
94 int ndeps; /* number of dependencies */
95 linker_file_t* deps; /* list of dependencies */
96 STAILQ_HEAD(, common_symbol) common; /* list of common symbols */
97 TAILQ_HEAD(, module) modules; /* modules in this file */
98 TAILQ_ENTRY(linker_file) loaded; /* preload dependency support */
99 int loadcnt; /* load counter value */
100
101 /*
102 * Function Boundary Tracing (FBT) or Statically Defined Tracing (SDT)
103 * fields.
104 */
105 int nenabled; /* number of enabled probes. */
106 int fbt_nentries; /* number of fbt entries created. */
107
108#ifdef __arm__
109 caddr_t exidx_addr; /* Unwind data index table start */
110 size_t exidx_size; /* Unwind data index table size */
111#endif
112};
113
114/*
115 * Object implementing a class of file (a.out, elf, etc.)
116 */
117typedef struct linker_class *linker_class_t;
118typedef TAILQ_HEAD(, linker_class) linker_class_list_t;
119
120struct linker_class {
121 KOBJ_CLASS_FIELDS;
122 TAILQ_ENTRY(linker_class) link; /* list of all file classes */
123};
124
125/*
126 * Function type used when iterating over the list of linker files.
127 */
128typedef int linker_predicate_t(linker_file_t, void *);
129
130/*
131 * The "file" for the kernel.
132 */
133extern linker_file_t linker_kernel_file;
134
135/*
136 * Special symbol which will be replaced by a reference to the linker_file_t
137 * of the module it is used in.
138 */
139extern linker_file_t __this_linker_file;
140
141/*
142 * Obtain a reference to a module, loading it if required.
143 */
144int linker_reference_module(const char* _modname, struct mod_depend *_verinfo,
145 linker_file_t* _result);
146
147/*
148 * Release a reference to a module, unloading it if there are no more
149 * references. Note that one should either provide a module name and
150 * optional version info or a linker file, but not both.
151 */
152int linker_release_module(const char *_modname, struct mod_depend *_verinfo,
153 linker_file_t _file);
154
155/*
156 * Iterate over all of the currently loaded linker files calling the
157 * predicate function while the function returns 0. Returns the value
158 * returned by the last predicate function.
159 */
160int linker_file_foreach(linker_predicate_t *_predicate, void *_context);
161
162/*
163 * Lookup a symbol in a file. If deps is TRUE, look in dependencies
164 * if not found in file.
165 */
166caddr_t linker_file_lookup_symbol(linker_file_t _file, const char* _name,
167 int _deps);
168
169/*
170 * Lookup a linker set in a file. Return pointers to the first entry,
171 * last + 1, and count of entries. Use: for (p = start; p < stop; p++) {}
172 * void *start is really: "struct yoursetmember ***start;"
173 */
174int linker_file_lookup_set(linker_file_t _file, const char *_name,
175 void *_start, void *_stop, int *_count);
176
177/*
178 * List all functions in a file.
179 */
180int linker_file_function_listall(linker_file_t,
181 linker_function_nameval_callback_t, void *);
182
183/*
184 * Functions solely for use by the linker class handlers.
185 */
186int linker_add_class(linker_class_t _cls);
187int linker_file_unload(linker_file_t _file, int flags);
188int linker_load_dependencies(linker_file_t _lf);
189linker_file_t linker_make_file(const char* _filename, linker_class_t _cls);
190
191/*
192 * DDB Helpers, tuned specifically for ddb/db_kld.c
193 */
194int linker_ddb_lookup(const char *_symstr, c_linker_sym_t *_sym);
195int linker_ddb_search_symbol(caddr_t _value, c_linker_sym_t *_sym,
196 long *_diffp);
197int linker_ddb_symbol_values(c_linker_sym_t _sym, linker_symval_t *_symval);
198int linker_ddb_search_symbol_name(caddr_t value, char *buf, u_int buflen,
199 long *offset);
200
201/*
202 * stack(9) helper for situations where kernel locking is required.
203 */
204int linker_search_symbol_name_flags(caddr_t value, char *buf, u_int buflen,
205 long *offset, int flags);
206int linker_search_symbol_name(caddr_t value, char *buf, u_int buflen,
207 long *offset);
208
209/* HWPMC helper */
210void *linker_hwpmc_list_objects(void);
211
212/* kldload/kldunload syscalls blocking */
213#define LINKER_UB_UNLOCK 0x0001 /* busy: unlock kld_sx locked on
214 return */
215#define LINKER_UB_LOCKED 0x0002 /* busy/unbusy: kld_sx locked on
216 entry */
217#define LINKER_UB_PCATCH 0x0004 /* busy: sleep interruptible */
218int linker_kldload_busy(int flags);
219void linker_kldload_unbusy(int flags);
220
221#endif /* _KERNEL */
222
223/*
224 * ELF file types
225 */
226#define KERNTYPE_MB "elf multiboot kernel"
227#define KERNTYPE "elf kernel"
228#define MODTYPE_OBJ "elf obj module"
229#define MODTYPE "elf module"
230
231/*
232 * Module information subtypes
233 */
234#define MODINFO_END 0x0000 /* End of list */
235#define MODINFO_NAME 0x0001 /* Name of module (string) */
236#define MODINFO_TYPE 0x0002 /* Type of module (string) */
237#define MODINFO_ADDR 0x0003 /* Loaded address */
238#define MODINFO_SIZE 0x0004 /* Size of module */
239#define MODINFO_EMPTY 0x0005 /* Has been deleted */
240#define MODINFO_ARGS 0x0006 /* Parameters string */
241#define MODINFO_METADATA 0x8000 /* Module-specfic */
242
243#define MODINFOMD_AOUTEXEC 0x0001 /* a.out exec header */
244#define MODINFOMD_ELFHDR 0x0002 /* ELF header */
245#define MODINFOMD_SSYM 0x0003 /* start of symbols */
246#define MODINFOMD_ESYM 0x0004 /* end of symbols */
247#define MODINFOMD_DYNAMIC 0x0005 /* _DYNAMIC pointer */
248#define MODINFOMD_MB2HDR 0x0006 /* MB2 header info */
249/* These values are MD on PowerPC */
250#if !defined(__powerpc__)
251#define MODINFOMD_ENVP 0x0006 /* envp[] */
252#define MODINFOMD_HOWTO 0x0007 /* boothowto */
253#define MODINFOMD_KERNEND 0x0008 /* kernend */
254#endif
255#define MODINFOMD_SHDR 0x0009 /* section header table */
256#define MODINFOMD_CTORS_ADDR 0x000a /* address of .ctors */
257#define MODINFOMD_CTORS_SIZE 0x000b /* size of .ctors */
258#define MODINFOMD_FW_HANDLE 0x000c /* Firmware dependent handle */
259#define MODINFOMD_KEYBUF 0x000d /* Crypto key intake buffer */
260#define MODINFOMD_FONT 0x000e /* Console font */
261#define MODINFOMD_SPLASH 0x000f /* Console splash screen */
262#define MODINFOMD_NOCOPY 0x8000 /* don't copy this metadata to the kernel */
263
264#define MODINFOMD_DEPLIST (0x4001 | MODINFOMD_NOCOPY) /* depends on */
265
266#ifdef _KERNEL
267#define MD_FETCH(mdp, info, type) ({ \
268 type *__p; \
269 __p = (type *)preload_search_info((mdp), MODINFO_METADATA | (info)); \
270 __p ? *__p : 0; \
271})
272#endif
273
274#define LINKER_HINTS_VERSION 1 /* linker.hints file version */
275#define LINKER_HINTS_MAX (1 << 20) /* Allow at most 1MB for linker.hints */
276
277#ifdef _KERNEL
278
279/*
280 * Module lookup
281 */
282extern vm_offset_t preload_addr_relocate;
283extern caddr_t preload_metadata, preload_kmdp;
284extern const char preload_modtype[];
285extern const char preload_kerntype[];
286extern const char preload_modtype_obj[];
287
288extern void * preload_fetch_addr(caddr_t _mod);
289extern size_t preload_fetch_size(caddr_t _mod);
290extern caddr_t preload_search_by_name(const char *_name);
291extern caddr_t preload_search_by_type(const char *_type);
292extern caddr_t preload_search_next_name(caddr_t _base);
293extern caddr_t preload_search_info(caddr_t _mod, int _inf);
294extern void preload_initkmdp(bool _fatal);
295extern void preload_delete_name(const char *_name);
296extern void preload_bootstrap_relocate(vm_offset_t _offset);
297extern void preload_dump(void);
298
299#ifdef KLD_DEBUG
300
301extern int kld_debug;
302#define KLD_DEBUG_FILE 1 /* file load/unload */
303#define KLD_DEBUG_SYM 2 /* symbol lookup */
304
305#define KLD_DPF(cat, args) \
306 do { \
307 if (kld_debug & KLD_DEBUG_##cat) printf args; \
308 } while (0)
309
310#else
311
312#define KLD_DPF(cat, args)
313
314#endif
315
316typedef int elf_lookup_fn(linker_file_t, Elf_Size, int, Elf_Addr *);
317
318/* Support functions */
319bool elf_is_ifunc_reloc(Elf_Size r_info);
320int elf_reloc(linker_file_t _lf, Elf_Addr base, const void *_rel,
321 int _type, elf_lookup_fn _lu);
322int elf_reloc_local(linker_file_t _lf, Elf_Addr base, const void *_rel,
323 int _type, elf_lookup_fn _lu);
324Elf_Addr elf_relocaddr(linker_file_t _lf, Elf_Addr addr);
325const Elf_Sym *elf_get_sym(linker_file_t _lf, Elf_Size _symidx);
326const char *elf_get_symname(linker_file_t _lf, Elf_Size _symidx);
327void link_elf_ireloc(void);
328
329#if defined(__aarch64__) || defined(__amd64__)
330int elf_reloc_late(linker_file_t _lf, Elf_Addr base, const void *_rel,
331 int _type, elf_lookup_fn _lu);
332void link_elf_late_ireloc(void);
333#endif
334
335typedef struct linker_ctf {
336 const uint8_t *ctftab; /* Decompressed CTF data. */
337 int ctfcnt; /* Number of CTF data bytes. */
338 const Elf_Sym *symtab; /* Ptr to the symbol table. */
339 int nsym; /* Number of symbols. */
340 const char *strtab; /* Ptr to the string table. */
341 int strcnt; /* Number of string bytes. */
342 uint32_t **ctfoffp; /* Ptr to array of obj/fnc offsets. */
343 uint32_t **typoffp; /* Ptr to array of type offsets. */
344 long *typlenp; /* Ptr to number of type data entries. */
345} linker_ctf_t;
346
347int linker_ctf_get(linker_file_t, linker_ctf_t *);
348int linker_ctf_lookup_sym_ddb(const char *symname, c_linker_sym_t *sym,
349 linker_ctf_t *lc);
350int linker_ctf_lookup_typename_ddb(linker_ctf_t *lc, const char *typename);
351
352int elf_cpu_load_file(linker_file_t);
353int elf_cpu_unload_file(linker_file_t);
354int elf_cpu_parse_dynamic(caddr_t, Elf_Dyn *);
355
356/* values for type */
357#define ELF_RELOC_REL 1
358#define ELF_RELOC_RELA 2
359
360/*
361 * This is version 1 of the KLD file status structure. It is identified
362 * by its _size_ in the version field.
363 */
364struct kld_file_stat_1 {
365 int version; /* set to sizeof(struct kld_file_stat_1) */
366 char name[MAXPATHLEN];
367 int refs;
368 int id;
369 caddr_t address; /* load address */
370 size_t size; /* size in bytes */
371};
372#endif /* _KERNEL */
373
374struct kld_file_stat {
375 int version; /* set to sizeof(struct kld_file_stat) */
376 char name[MAXPATHLEN];
377 int refs;
378 int id;
379 caddr_t address; /* load address */
380 size_t size; /* size in bytes */
381 char pathname[MAXPATHLEN];
382};
383
384struct kld_sym_lookup {
385 int version; /* set to sizeof(struct kld_sym_lookup) */
386 char *symname; /* Symbol name we are looking up */
387 u_long symvalue;
388 size_t symsize;
389};
390#define KLDSYM_LOOKUP 1
391
392/*
393 * Flags for kldunloadf() and linker_file_unload()
394 */
395#define LINKER_UNLOAD_NORMAL 0
396#define LINKER_UNLOAD_FORCE 1
397
398#ifndef _KERNEL
399
400#include <sys/cdefs.h>
401
402__BEGIN_DECLS
403int kldload(const char* _file);
404int kldunload(int _fileid);
405int kldunloadf(int _fileid, int flags);
406int kldfind(const char* _file);
407int kldnext(int _fileid);
408int kldstat(int _fileid, struct kld_file_stat* _stat);
409int kldfirstmod(int _fileid);
410int kldsym(int _fileid, int _cmd, void *_data);
411__END_DECLS
412
413#endif
414
415#endif /* !_SYS_LINKER_H_ */