summaryrefslogtreecommitdiff
path: root/libexec/ld.so/resolve.h
blob: 2930fd9fbb99cd527bcb79718b3d7904b1eee376 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
/*	$OpenBSD: resolve.h,v 1.39 2005/09/21 23:12:09 drahn Exp $ */

/*
 * Copyright (c) 1998 Per Fogelstrom, Opsycon AB
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 */

#ifndef _RESOLVE_H_
#define _RESOLVE_H_

#include <sys/queue.h>
#include <link.h>
#include <dlfcn.h>

struct load_list {
	struct load_list *next;
	void		*start;
	size_t		size;
	int		prot;
	Elf_Addr	moff;
	long		foff;
};

/*
 *  Structure describing a loaded object.
 *  The head of this struct must be compatible
 *  with struct link_map in sys/link.h
 */
typedef struct elf_object elf_object_t;
struct elf_object {
	Elf_Addr load_addr;		/* Real load address */
	char	*load_name;		/* Pointer to object name */
	Elf_Dyn *load_dyn;		/* Pointer to object dynamic data */
	struct elf_object *next;
	struct elf_object *prev;
/* End struct link_map compatible */
	Elf_Addr load_offs;		/* Load offset from link address */

	struct load_list *load_list;

	u_int32_t  load_size;
	Elf_Addr	got_addr;
	Elf_Addr	got_start;
	size_t		got_size;
	Elf_Addr	plt_start;
	size_t		plt_size;

	union {
		u_long		info[DT_NUM + DT_PROCNUM];
		struct {
			Elf_Addr	null;		/* Not used */
			Elf_Addr	needed;		/* Not used */
			Elf_Addr	pltrelsz;
			Elf_Addr	*pltgot;
			Elf_Addr	*hash;
			const char	*strtab;
			const Elf_Sym	*symtab;
			Elf_RelA	*rela;
			Elf_Addr	relasz;
			Elf_Addr	relaent;
			Elf_Addr	strsz;
			Elf_Addr	syment;
			void		(*init)(void);
			void		(*fini)(void);
			const char	*soname;
			const char	*rpath;
			Elf_Addr	symbolic;
			Elf_Rel	*rel;
			Elf_Addr	relsz;
			Elf_Addr	relent;
			Elf_Addr	pltrel;
			Elf_Addr	debug;
			Elf_Addr	textrel;
			Elf_Addr	jmprel;
			Elf_Addr	bind_now;
		} u;
	} Dyn;
#define dyn Dyn.u

	struct elf_object *dep_next;	/* Shadow objects for resolve search */

	int		status;
#define	STAT_RELOC_DONE	0x01
#define	STAT_GOT_DONE	0x02
#define	STAT_INIT_DONE	0x04
#define	STAT_FINI_DONE	0x08
#define	STAT_FINI_READY	0x10

	Elf_Phdr	*phdrp;
	int		phdrc;

	int		refcount;
	int		obj_type;
#define	OBJTYPE_LDR	1
#define	OBJTYPE_EXE	2
#define	OBJTYPE_LIB	3
#define	OBJTYPE_DLO	4
	int		obj_flags;

	Elf_Word	*buckets;
	u_int32_t	nbuckets;
	Elf_Word	*chains;
	u_int32_t	nchains;
	Elf_Dyn		*dynamic;

	TAILQ_HEAD(,dep_node)	child_list;
	TAILQ_HEAD(,dep_node)	dload_list;

	/* object that caused this module to be loaded, used in symbol lookup */
	elf_object_t	*load_object;

	/* for object confirmation */
	dev_t	dev;
	ino_t inode;
};

struct dep_node {
	TAILQ_ENTRY(dep_node) next_sib;
	elf_object_t *data;
};

void _dl_rt_resolve(void);

void _dl_add_object(elf_object_t *object);
elf_object_t *_dl_finalize_object(const char *objname, Elf_Dyn *dynp,
    const long *, const int objtype, const long laddr, const long loff);
void	_dl_remove_object(elf_object_t *object);

elf_object_t *_dl_lookup_object(const char *objname);
elf_object_t *_dl_load_shlib(const char *, elf_object_t *, int, int);
elf_object_t *_dl_tryload_shlib(const char *libname, int type, int flags);

int  _dl_md_reloc(elf_object_t *object, int rel, int relsz);
void _dl_md_reloc_got(elf_object_t *object, int lazy);

Elf_Addr _dl_find_symbol(const char *name, const Elf_Sym **this,
    int flags, const Elf_Sym *ref_sym, elf_object_t *object,
    const elf_object_t **pobj);
Elf_Addr _dl_find_symbol_bysym(elf_object_t *req_obj, unsigned int symidx,
    const Elf_Sym **ref, int flags, const Elf_Sym *ref_sym,
    const elf_object_t **pobj);
/*
 * defines for _dl_find_symbol() flag field, three bits of meaning
 * myself	- clear: search all objects,	set: search only this object
 * warnnotfound - clear: no warning,		set: warn if not found
 * inplt	- clear: possible plt ref	set: real matching function.
 *
 * inplt - due to how ELF handles function addresses in shared libraries
 * &func may actually refer to the plt entry in the main program
 * rather than the actual function address in the .so file.
 * This rather bizarre behavior is documented in the SVR4 ABI.
 * when getting the function address to relocate a PLT entry
 * the 'real' function address is necessary, not the possible PLT address.
 */
/* myself */
#define SYM_SEARCH_ALL		0x00
#define SYM_SEARCH_SELF		0x01
#define SYM_SEARCH_OTHER	0x02
#define SYM_SEARCH_NEXT		0x04
#define SYM_SEARCH_OBJ		0x08
/* warnnotfound */
#define SYM_NOWARNNOTFOUND	0x00
#define SYM_WARNNOTFOUND	0x10
/* inplt */
#define SYM_NOTPLT		0x00
#define SYM_PLT			0x20

#define SYM_DLSYM		0x40

void _dl_rtld(elf_object_t *object);
void _dl_call_init(elf_object_t *object);
void _dl_link_sub(elf_object_t *dep, elf_object_t *p);
void _dl_link_dlopen(elf_object_t *dep);
void _dl_unlink_dlopen(elf_object_t *dep);
void _dl_notify_unload_shlib(elf_object_t *object);
void _dl_unload_shlib(elf_object_t *object);
void _dl_unload_dlopen(void);

void _dl_run_dtors(elf_object_t *object);
void _dl_run_all_dtors(void);

Elf_Addr _dl_bind(elf_object_t *object, int index);

int	_dl_match_file(struct sod *sodp, char *name, int namelen);
char	*_dl_find_shlib(struct sod *sodp, const char *searchpath, int nohints);
void	_dl_load_list_free(struct load_list *load_list);

void	_dl_thread_kern_go(void);
void	_dl_thread_kern_stop(void);

extern elf_object_t *_dl_objects;
extern elf_object_t *_dl_last_object;

extern elf_object_t *_dl_loading_object;

extern const char *_dl_progname;
extern struct r_debug *_dl_debug_map;

extern int  _dl_pagesz;
extern int  _dl_errno;
extern int  _dl_exiting;

extern char *_dl_libpath;
extern char *_dl_preload;
extern char *_dl_bindnow;
extern char *_dl_traceld;
extern char *_dl_debug;

#define DL_DEB(P) do { if (_dl_debug) _dl_printf P ; } while (0)

#define	DL_NOT_FOUND		1
#define	DL_CANT_OPEN		2
#define	DL_NOT_ELF		3
#define	DL_CANT_OPEN_REF	4
#define	DL_CANT_MMAP		5
#define	DL_NO_SYMBOL		6
#define	DL_INVALID_HANDLE	7
#define	DL_INVALID_CTL		8
#define	DL_NO_OBJECT		9
#define	DL_CANT_FIND_OBJ	10
#define	DL_CANT_LOAD_OBJ	11

#define ELF_ROUND(x,malign) (((x) + (malign)-1) & ~((malign)-1))
#define ELF_TRUNC(x,malign) ((x) & ~((malign)-1))

/* symbol lookup cache */
typedef struct sym_cache {
	const elf_object_t *obj;
	const Elf_Sym	*sym;
	int flags;
} sym_cache;

extern sym_cache *_dl_symcache;
extern int _dl_symcachestat_hits;
extern int _dl_symcachestat_lookups;
TAILQ_HEAD(dlochld, dep_node);
extern struct dlochld _dlopened_child_list;


#endif /* _RESOLVE_H_ */